Botswana the Republic of Botswana, is a landlocked country in Southern Africa. The British protectorate of Bechuanaland, Botswana adopted its new name after becoming independent within the Commonwealth on 30 September 1966. Since it has maintained a tradition of stable representative republic, with a consistent record of uninterrupted democratic elections and the best perceived corruption ranking in Africa since at least 1998, it is Africa's oldest continuous democracy. Botswana is topographically flat, with up to 70 percent of its territory being the Kalahari Desert, it is bordered by South Africa to the south and southeast, Namibia to the west and north, Zimbabwe to the northeast. Its border with Zambia to the north near Kazungula is poorly defined but is, at most, a few hundred metres long. A mid-sized country of just over 2 million people, Botswana is one of the most sparsely populated countries in the world. Around 10 percent of the population lives in the capital and largest city, Gaborone.
One of the poorest countries in the world—with a GDP per capita of about US$70 per year in the late 1960s—Botswana has since transformed itself into one of the world's fastest-growing economies. The economy is dominated by mining and tourism. Botswana boasts a GDP per capita of about $18,825 per year as of 2015, one of the highest in Africa, its high gross national income gives the country a high standard of living and the highest Human Development Index of continental Sub-Saharan Africa. Botswana is a member of the African Union, the Southern African Development Community, the Commonwealth of Nations, the United Nations; the country has been among the hardest hit by the HIV/AIDS epidemic. Despite the success in programmes to make treatments available to those infected, to educate the populace in general about how to stop the spread of HIV/AIDS, the number of people with AIDS rose from 290,000 in 2005 to 320,000 in 2013; as of 2014, Botswana has the third-highest prevalence rate for HIV/AIDS, with 20% of the population infected.
The country's name means "land of the tswana", referring to the dominant ethnic group in Botswana. The term Batswana was applied to the Tswana, still the case. However, it has come to be used as a demonym for all citizens of Botswana. Many English dictionaries recommend the term Botswanan to refer to people of Botswana. Archaeological digs have shown. Stone tools and fauna remains have shown that all areas of the country were inhabited at least 400,000 years ago. Evidence left by modern humans such as cave paintings are about 73,000 years old; the original inhabitants of southern Africa were the Khoi peoples. Both speak Khoisan languages and hunted and traded over long distances; when cattle were first introduced about 2000 years ago into southern Africa, pastoralism became a major feature of the economy, since the region had large grasslands free of tsetse fly. It is unclear when Bantu-speaking peoples first moved into the country from the north, although AD 600 seems to be a consensus estimate.
In that era, the ancestors of the modern-day Kalanga moved into what is now the north-eastern areas of the country. These proto-Kalanga were connected to states in Zimbabwe as well as to the Mapungubwe state; these states, located outside of current Botswana's borders, appear to have kept massive cattle herds in what is now the Central District—apparently at numbers approaching modern cattle density. This massive cattle-raising complex prospered until 1300 AD or so, seems to have regressed following the collapse of Mapungubwe. During this era, the first Tswana-speaking groups, the Bakgalagadi, moved into the southern areas of the Kalahari. All these various peoples were connected to trade routes that ran via the Limpopo River to the Indian Ocean, trade goods from Asia such as beads made their way to Botswana most in exchange for ivory and rhinoceros horn; the arrival of the ancestors of the Tswana-speakers who came to control the region has yet to be dated precisely. Members of the Bakwena, a chieftaincy under a legendary leader named Kgabo II, made their way into the southern Kalahari by AD 1500, at the latest, his people drove the Bakgalagadi inhabitants west into the desert.
Over the years, several offshoots of the Bakwena moved into adjoining territories. The Bangwaketse occupied areas to the west, while the Bangwato moved northeast into Kalanga areas. Not long afterwards, a Bangwato offshoot known as the Batawana migrated into the Okavango Delta in the 1790s; the first written records relating to modern-day Botswana appear in 1824. What these records show is that the Bangwaketse had become the predominant power in the region. Under the rule of Makaba II, the Bangwaketse kept vast herds of cattle in well-protected desert areas, used their military prowess to raid their neighbors. Other chiefdoms in the area, by this time, had capitals of 10,000 or so and were prosperous; this equilibrium came to end during the Mfecane period, 1823–1843, when a succession of invading peoples from South Africa entered the country. Although the Bangwaketse were able to defeat the invading Bakololo in 1826, over time all the major chiefdoms in Botswana were attacked and impoverished.
The Bakololo and Amandebele raided and took large numbers of cattle and children from the Batswana—most of whom were driven into the desert or sanctuary areas such as hilltops and caves. Only after 1843, when the Amandebele moved into western Zimbabwe, did this threat subside. During th
In geometry, a dodecagon or 12-gon is any twelve-sided polygon. A regular dodecagon is a figure with internal angles of the same size, it has twelve lines of reflective symmetry and rotational symmetry of order 12. A regular dodecagon is represented by the Schläfli symbol and can be constructed as a truncated hexagon, t, or a twice-truncated triangle, tt; the internal angle at each vertex of a regular dodecagon is 150°. The area of a regular dodecagon of side length a is given by: A = 3 cot a 2 = 3 a 2 ≃ 11.19615242 a 2 And in terms of the apothem r, the area is: A = 12 tan r 2 = 12 r 2 ≃ 3.2153903 r 2 In terms of the circumradius R, the area is: A = 6 sin R 2 = 3 R 2 The span S of the dodecagon is the distance between two parallel sides and is equal to twice the apothem. A simple formula for area is: A = 3 a S This can be verified with the trigonometric relationship: S = a The perimeter of a regular dodecagon in terms of circumradius is: p = 24 R tan = 12 R 2 − 3 ≃ 6.21165708246 R The perimeter in terms of apothem is: p = 24 r tan = 24 r ≃ 6.43078061835 r This coefficient is double the coefficient found in the apothem equation for area.
As 12 = 22 × 3, regular dodecagon is constructible using compass-and-straightedge construction: Coxeter states that every zonogon can be dissected into m/2 parallelograms. In particular this is true for regular polygons with evenly many sides, in which case the parallelograms are all rhombi. For the regular dodecagon, m=6, it can be divided into 15: 3 squares, 6 wide 30° rhombs and 6 narrow 15° rhombs; this decomposition is based with 15 of 240 faces. The sequence OEIS sequence A006245 defines the number of solutions as 908, including up to 12-fold rotations and chiral forms in reflection. One of the ways the mathematical manipulative pattern blocks are used is in creating a number of different dodecagons, they are related to the rhombic dissections, with 3 60° rhombi merged into hexagons, half-hexagon trapezoids, or divided into 2 equilateral triangles. The regular dodecagon has Dih12 symmetry, order 24. There are 15 distinct subgroup cyclic symmetries; each subgroup symmetry allows one or more degrees of freedom for irregular forms.
Only the g12 subgroup has no degrees of freedom. A regular dodecagon can fill a plane vertex with other regular polygons in 4 ways: Here are 3 example periodic plane tilings that use regular dodecagons, defined by their vertex configuration: A skew dodecagon is a skew polygon with 12 vertices and edges but not existing on the same plane; the interior of such an dodecagon is not defined. A skew zig-zag. A regular skew dodecagon is vertex-transitive with equal edge lengths. In 3-dimensions it will be a zig-zag skew dodecagon and can be seen in the vertices and side edges of a hexagonal antiprism with the same D5d, order
Zimbabwe the Republic of Zimbabwe, is a landlocked country located in southern Africa, between the Zambezi and Limpopo Rivers, bordered by South Africa, Botswana and Mozambique. The capital and largest city is Harare. A country of 16 million people, Zimbabwe has 16 official languages, with English and Ndebele the most used. Since the 11th century, present-day Zimbabwe has been the site of several organised states and kingdoms as well as a major route for migration and trade; the British South Africa Company of Cecil Rhodes first demarcated the present territory during the 1890s. In 1965, the conservative white minority government unilaterally declared independence as Rhodesia; the state endured a 15-year guerrilla war with black nationalist forces. Zimbabwe joined the Commonwealth of Nations, from which it was suspended in 2002 for breaches of international law by its then-government, from which it withdrew in December 2003; the sovereign state is a member of the United Nations, the Southern African Development Community, the African Union, the Common Market for Eastern and Southern Africa.
It was once known as the "Jewel of Africa" for its prosperity under the former Rhodesian administration. Robert Mugabe became Prime Minister of Zimbabwe in 1980, when his ZANU-PF party won the elections following the end of white minority rule. Under Mugabe's authoritarian regime, the state security apparatus dominated the country and was responsible for widespread human rights violations. Mugabe maintained the revolutionary socialist rhetoric of the Cold War era, blaming Zimbabwe's economic woes on conspiring Western capitalist countries. Contemporary African political leaders were reluctant to criticise Mugabe, burnished by his anti-imperialist credentials, though Archbishop Desmond Tutu called him "a cartoon figure of an archetypal African dictator"; the country has been in economic decline since the 1990s, experiencing several crashes and hyperinflation along the way. On 15 November 2017, in the wake of over a year of protests against his government as well as Zimbabwe's declining economy, Mugabe was placed under house arrest by the country's national army in a coup d'état.
On 19 November 2017, ZANU-PF sacked Robert Mugabe as party leader and appointed former Vice President Emmerson Mnangagwa in his place. On 21 November 2017, Mugabe tendered his resignation prior to impeachment proceedings being completed. On 30 July 2018 Zimbabwe held its general elections, won by the ZANU-PF party led by Emmerson Mnangagwa. Nelson Chamisa, leading the main opposition party MDC Alliance contested the election results and filed a petition to the Constitution Court of Zimbabwe; the court confirmed Mnangagwa's victory. The name "Zimbabwe" stems from a Shona term for Great Zimbabwe, an ancient ruined city in the country's south-east whose remains are now a protected site. Two different theories address the origin of the word. Many sources hold that "Zimbabwe" derives from dzimba-dza-mabwe, translated from the Karanga dialect of Shona as "houses of stones"; the Karanga-speaking Shona people live around Great Zimbabwe in the modern-day province of Masvingo. Archaeologist Peter Garlake claims that "Zimbabwe" represents a contracted form of dzimba-hwe, which means "venerated houses" in the Zezuru dialect of Shona and references chiefs' houses or graves.
Zimbabwe was known as Southern Rhodesia and Zimbabwe Rhodesia. The first recorded use of "Zimbabwe" as a term of national reference dates from 1960 as a coinage by the black nationalist Michael Mawema, whose Zimbabwe National Party became the first to use the name in 1961; the term "Rhodesia"—derived from the surname of Cecil Rhodes, the primary instigator of British colonisation of the territory during the late 19th century—was perceived by African nationalists as inappropriate because of its colonial origin and connotations. According to Mawema, black nationalists held a meeting in 1960 to choose an alternative name for the country, proposing names such as "Matshobana" and "Monomotapa" before his suggestion, "Zimbabwe", prevailed. A further alternative, put forward by nationalists in Matabeleland, had been "Matopos", referring to the Matopos Hills to the south of Bulawayo, it was unclear how the chosen term was to be used—a letter written by Mawema in 1961 refers to "Zimbabweland" — but "Zimbabwe" was sufficiently established by 1962 to become the preferred term of the black nationalist movement.
In a 2001 interview, black nationalist Edson Zvobgo recalled that Mawema mentioned the name during a political rally, "and it caught hold, and, that". The black nationalist factions subsequently used the name during the Second Chimurenga campaigns against the Rhodesian government during the Rhodesian Bush War of 1964–1979. Major factions in this camp included the Zimbabwe African National Union, the Zimbabwe African People's Union. Archaeological records date human settlement of present-day Zimbabwe to at least 100,000 years ago; the earliest known inhabitants were San people, who left behind arrowheads and cave paintings. The first Bantu-speaking farmers arrived during the Bantu expansion around 2000 years ago. Societies speaking proto-Shona languages fir
Rain is liquid water in the form of droplets that have condensed from atmospheric water vapor and become heavy enough to fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth, it provides suitable conditions for many types of ecosystems, as well as water for hydroelectric power plants and crop irrigation. The major cause of rain production is moisture moving along three-dimensional zones of temperature and moisture contrasts known as weather fronts. If enough moisture and upward motion is present, precipitation falls from convective clouds such as cumulonimbus which can organize into narrow rainbands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation which forces moist air to condense and fall out as rainfall along the sides of mountains. On the leeward side of mountains, desert climates can exist due to the dry air caused by downslope flow which causes heating and drying of the air mass.
The movement of the monsoon trough, or intertropical convergence zone, brings rainy seasons to savannah climes. The urban heat island effect leads to increased rainfall, both in amounts and intensity, downwind of cities. Global warming is causing changes in the precipitation pattern globally, including wetter conditions across eastern North America and drier conditions in the tropics. Antarctica is the driest continent; the globally averaged annual precipitation over land is 715 mm, but over the whole Earth it is much higher at 990 mm. Climate classification systems such as the Köppen classification system use average annual rainfall to help differentiate between differing climate regimes. Rainfall is measured using rain gauges. Rainfall amounts can be estimated by weather radar. Rain is known or suspected on other planets, where it may be composed of methane, sulfuric acid, or iron rather than water. Air contains water vapor, the amount of water in a given mass of dry air, known as the mixing ratio, is measured in grams of water per kilogram of dry air.
The amount of moisture in air is commonly reported as relative humidity. How much water vapor a parcel of air can contain before it becomes saturated and forms into a cloud depends on its temperature. Warmer air can contain more water vapor than cooler air before becoming saturated. Therefore, one way to saturate a parcel of air is to cool it; the dew point is the temperature. There are four main mechanisms for cooling the air to its dew point: adiabatic cooling, conductive cooling, radiational cooling, evaporative cooling. Adiabatic cooling occurs when air expands; the air can rise due to convection, large-scale atmospheric motions, or a physical barrier such as a mountain. Conductive cooling occurs when the air comes into contact with a colder surface by being blown from one surface to another, for example from a liquid water surface to colder land. Radiational cooling occurs due to the emission of infrared radiation, either by the air or by the surface underneath. Evaporative cooling occurs when moisture is added to the air through evaporation, which forces the air temperature to cool to its wet-bulb temperature, or until it reaches saturation.
The main ways water vapor is added to the air are: wind convergence into areas of upward motion, precipitation or virga falling from above, daytime heating evaporating water from the surface of oceans, water bodies or wet land, transpiration from plants, cool or dry air moving over warmer water, lifting air over mountains. Water vapor begins to condense on condensation nuclei such as dust and salt in order to form clouds. Elevated portions of weather fronts force broad areas of upward motion within the Earth's atmosphere which form clouds decks such as altostratus or cirrostratus. Stratus is a stable cloud deck which tends to form when a cool, stable air mass is trapped underneath a warm air mass, it can form due to the lifting of advection fog during breezy conditions. Coalescence occurs. Air resistance causes the water droplets in a cloud to remain stationary; when air turbulence occurs, water droplets collide. As these larger water droplets descend, coalescence continues, so that drops become heavy enough to overcome air resistance and fall as rain.
Coalescence happens most in clouds above freezing, is known as the warm rain process. In clouds below freezing, when ice crystals gain enough mass they begin to fall; this requires more mass than coalescence when occurring between the crystal and neighboring water droplets. This process is temperature dependent, as supercooled water droplets only exist in a cloud, below freezing. In addition, because of the great temperature difference between cloud and ground level, these ice crystals may melt as they fall and become rain. Raindrops have sizes ranging from 0.1 to 9 mm mean diameter. Smaller drops are called cloud droplets, their shape is spherical; as a raindrop increases in size, its shape becomes more oblate, with its largest cross-section facing the oncoming airflow. Large rain drops become flattened on the bottom, like hamburger buns. Contrary to popular beli
Bronze is an alloy consisting of copper with about 12–12.5% tin and with the addition of other metals and sometimes non-metals or metalloids such as arsenic, phosphorus or silicon. These additions produce a range of alloys that may be harder than copper alone, or have other useful properties, such as stiffness, ductility, or machinability; the archeological period in which bronze was the hardest metal in widespread use is known as the Bronze Age. The beginning of the Bronze Age in India and western Eurasia is conventionally dated to the mid-4th millennium BC, to the early 2nd millennium BC in China; the Bronze Age was followed by the Iron Age starting from about 1300 BC and reaching most of Eurasia by about 500 BC, although bronze continued to be much more used than it is in modern times. Because historical pieces were made of brasses and bronzes with different compositions, modern museum and scholarly descriptions of older objects use the more inclusive term "copper alloy" instead. There are two basic theories as to the origin of the word.
Romance theoryThe Romance theory holds that the word bronze was borrowed from French bronze, itself borrowed from Italian bronzo "bell metal, brass" from either, bróntion, back-formation from Byzantine Greek brontēsíon from Brentḗsion ‘Brindisi’, reputed for its bronze. Proto-Slavic theoryThe Proto-Slavic theory reflects the philological issue that in the most of Slavonic languages word "bronza" corresponds to "war metal" while at the early stages of the Bronze working it was used exclusively for military purposes; the discovery of bronze enabled people to create metal objects which were harder and more durable than possible. Bronze tools, weapons and building materials such as decorative tiles were harder and more durable than their stone and copper predecessors. Bronze was made out of copper and arsenic, forming arsenic bronze, or from or artificially mixed ores of copper and arsenic, with the earliest artifacts so far known coming from the Iranian plateau in the 5th millennium BC, it was only that tin was used, becoming the major non-copper ingredient of bronze in the late 3rd millennium BC.
Tin bronze was superior to arsenic bronze in that the alloying process could be more controlled, the resulting alloy was stronger and easier to cast. Unlike arsenic, metallic tin and fumes from tin refining are not toxic; the earliest tin-alloy bronze dates to 4500 BC in a Vinča culture site in Pločnik. Other early examples date to the late 4th millennium BC in Egypt and some ancient sites in China and Mesopotamia. Ores of copper and the far rarer tin are not found together, so serious bronze work has always involved trade. Tin sources and trade in ancient times had a major influence on the development of cultures. In Europe, a major source of tin was the British deposits of ore in Cornwall, which were traded as far as Phoenicia in the eastern Mediterranean. In many parts of the world, large hoards of bronze artifacts are found, suggesting that bronze represented a store of value and an indicator of social status. In Europe, large hoards of bronze tools socketed axes, are found, which show no signs of wear.
With Chinese ritual bronzes, which are documented in the inscriptions they carry and from other sources, the case is clear. These were made in enormous quantities for elite burials, used by the living for ritual offerings. Though bronze is harder than wrought iron, with Vickers hardness of 60–258 vs. 30–80, the Bronze Age gave way to the Iron Age after a serious disruption of the tin trade: the population migrations of around 1200–1100 BC reduced the shipping of tin around the Mediterranean and from Britain, limiting supplies and raising prices. As the art of working in iron improved, iron improved in quality; as cultures advanced from hand-wrought iron to machine-forged iron, blacksmiths learned how to make steel. Steel holds a sharper edge longer. Bronze was still used during the Iron Age, has continued in use for many purposes to the modern day. There are many different bronze alloys, but modern bronze is 88% copper and 12% tin. Alpha bronze consists of the alpha solid solution of tin in copper.
Alpha bronze alloys of 4–5% tin are used to make coins, springs and blades. Historical "bronzes" are variable in composition, as most metalworkers used whatever scrap was on hand; the proportions of this mixture suggests. The Benin Bronzes are in fact brass, the Romanesque Baptismal font at St Bartholomew's Church, Liège is described as both bronze and brass. In the Bronze Age, two forms of bronze were used: "classic bronze", about 10% tin, was used in
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is hard and ductile. Pure nickel, powdered to maximize the reactive surface area, shows a significant chemical activity, but larger pieces are slow to react with air under standard conditions because an oxide layer forms on the surface and prevents further corrosion. So, pure native nickel is found in Earth's crust only in tiny amounts in ultramafic rocks, in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside Earth's atmosphere. Meteoric nickel is found in combination with iron, a reflection of the origin of those elements as major end products of supernova nucleosynthesis. An iron–nickel mixture is thought to compose Earth's outer and inner cores. Use of nickel has been traced as far back as 3500 BCE. Nickel was first isolated and classified as a chemical element in 1751 by Axel Fredrik Cronstedt, who mistook the ore for a copper mineral, in the cobalt mines of Los, Hälsingland, Sweden.
The element's name comes from a mischievous sprite of German miner mythology, who personified the fact that copper-nickel ores resisted refinement into copper. An economically important source of nickel is the iron ore limonite, which contains 1–2% nickel. Nickel's other important ore minerals include pentlandite and a mixture of Ni-rich natural silicates known as garnierite. Major production sites include the Sudbury region in Canada, New Caledonia in the Pacific, Norilsk in Russia. Nickel is oxidized by air at room temperature and is considered corrosion-resistant, it has been used for plating iron and brass, coating chemistry equipment, manufacturing certain alloys that retain a high silvery polish, such as German silver. About 9% of world nickel production is still used for corrosion-resistant nickel plating. Nickel-plated objects sometimes provoke nickel allergy. Nickel has been used in coins, though its rising price has led to some replacement with cheaper metals in recent years. Nickel is one of four elements that are ferromagnetic at room temperature.
Alnico permanent magnets based on nickel are of intermediate strength between iron-based permanent magnets and rare-earth magnets. The metal is valuable in modern times chiefly in alloys. A further 10% is used for nickel-based and copper-based alloys, 7% for alloy steels, 3% in foundries, 9% in plating and 4% in other applications, including the fast-growing battery sector; as a compound, nickel has a number of niche chemical manufacturing uses, such as a catalyst for hydrogenation, cathodes for batteries and metal surface treatments. Nickel is an essential nutrient for some microorganisms and plants that have enzymes with nickel as an active site. Nickel is a silvery-white metal with a slight golden tinge, it is one of only four elements that are magnetic at or near room temperature, the others being iron and gadolinium. Its Curie temperature is 355 °C; the unit cell of nickel is a face-centered cube with the lattice parameter of 0.352 nm, giving an atomic radius of 0.124 nm. This crystal structure is stable to pressures of at least 70 GPa.
Nickel belongs to the transition metals. It is hard and ductile, has a high for transition metals electrical and thermal conductivity; the high compressive strength of 34 GPa, predicted for ideal crystals, is never obtained in the real bulk material due to the formation and movement of dislocations. The nickel atom has two electron configurations, 3d8 4s2 and 3d9 4s1, which are close in energy – the symbol refers to the argon-like core structure. There is some disagreement. Chemistry textbooks quote the electron configuration of nickel as 4s2 3d8, which can be written 3d8 4s2; this configuration agrees with the Madelung energy ordering rule, which predicts that 4s is filled before 3d. It is supported by the experimental fact that the lowest energy state of the nickel atom is a 3d8 4s2 energy level the 3d8 4s2 3F, J = 4 level. However, each of these two configurations splits into several energy levels due to fine structure, the two sets of energy levels overlap; the average energy of states with configuration 3d9 4s1 is lower than the average energy of states with configuration 3d8 4s2.
For this reason, the research literature on atomic calculations quotes the ground state configuration of nickel as 3d9 4s1. The isotopes of nickel range in atomic weight from 48 u to 78 u. Occurring nickel is composed of five stable isotopes. Isotopes heavier than 62Ni cannot be formed by nuclear fusion without losing energy. Nickel-62 has the highest mean nuclear binding energy per nucleon of any nuclide, at 8.7946 MeV/nucleon. Its binding energy is greater than both 56Fe and 58Fe, more abundant elements incorrectly cited as having the most tightly-bound nuclides. Although this would seem to predict nickel-62 as the most abundant heavy element in the universe, the high rate of photodisintegration of nickel in stellar interiors causes iron to be by far the most abundant. Stable isotope nickel-60 is the daughter product of the extinct radionuclide 60Fe, whi
A central bank, reserve bank, or monetary authority is the institution that manages the currency, money supply, interest rates of a state or formal monetary union, oversees their commercial banking system. In contrast to a commercial bank, a central bank possesses a monopoly on increasing the monetary base in the state, generally controls the printing/coining of the national currency, which serves as the state's legal tender. A central bank acts as a lender of last resort to the banking sector during times of financial crisis. Most central banks have supervisory and regulatory powers to ensure the solvency of member institutions, to prevent bank runs, to discourage reckless or fraudulent behavior by member banks. Central banks in most developed nations are institutionally independent from political interference. Still, limited control by the executive and legislative bodies exists. Functions of a central bank may include: implementing monetary policies. Setting the official interest rate – used to manage both inflation and the country's exchange rate – and ensuring that this rate takes effect via a variety of policy mechanisms controlling the nation's entire money supply the Government's banker and the bankers' bank managing the country's foreign exchange and gold reserves and the Government bonds regulating and supervising the banking industry Central banks implement a country's chosen monetary policy.
At the most basic level, monetary policy involves establishing what form of currency the country may have, whether a fiat currency, gold-backed currency, currency board or a currency union. When a country has its own national currency, this involves the issue of some form of standardized currency, a form of promissory note: a promise to exchange the note for "money" under certain circumstances; this was a promise to exchange the money for precious metals in some fixed amount. Now, when many currencies are fiat money, the "promise to pay" consists of the promise to accept that currency to pay for taxes. A central bank may use another country's currency either directly in a currency union, or indirectly on a currency board. In the latter case, exemplified by the Bulgarian National Bank, Hong Kong and Latvia, the local currency is backed at a fixed rate by the central bank's holdings of a foreign currency. Similar to commercial banks, central banks incur liabilities. Central banks create money by issuing interest-free currency notes and selling them to the public in exchange for interest-bearing assets such as government bonds.
When a central bank wishes to purchase more bonds than their respective national governments make available, they may purchase private bonds or assets denominated in foreign currencies. The European Central Bank remits its interest income to the central banks of the member countries of the European Union; the US Federal Reserve remits all its profits to the U. S. Treasury; this income, derived from the power to issue currency, is referred to as seigniorage, belongs to the national government. The state-sanctioned power to create currency is called the Right of Issuance. Throughout history there have been disagreements over this power, since whoever controls the creation of currency controls the seigniorage income; the expression "monetary policy" may refer more narrowly to the interest-rate targets and other active measures undertaken by the monetary authority. Frictional unemployment is the time period between jobs when a worker is searching for, or transitioning from one job to another. Unemployment beyond frictional unemployment is classified as unintended unemployment.
For example, structural unemployment is a form of unemployment resulting from a mismatch between demand in the labour market and the skills and locations of the workers seeking employment. Macroeconomic policy aims to reduce unintended unemployment. Keynes labeled any jobs that would be created by a rise in wage-goods as involuntary unemployment: Men are involuntarily unemployed if, in the event of a small rise in the price of wage-goods to the money-wage, both the aggregate supply of labour willing to work for the current money-wage and the aggregate demand for it at that wage would be greater than the existing volume of employment.—John Maynard Keynes, The General Theory of Employment and Money p11 Inflation is defined either as the devaluation of a currency or equivalently the rise of prices relative to a currency. Since inflation lowers real wages, Keynesians view inflation as the solution to involuntary unemployment. However, "unanticipated" inflation leads to lender losses as the real interest rate will be lower than expected.
Thus, Keynesian monetary policy aims for a steady rate of inflation. A publication from the Austrian School, The Case Against the Fed, argues that the efforts of the central banks to control inflation have been counterproductive. Economic growth can be enhanced by investment such as more or better machinery. A low interest rate implies that firms can borrow money to invest in their capital stock and pay less interest for it. Lowering the interest is therefore considered to encourage economic growth and is used to alleviate times of low economic growth. On the other hand, raising the interest rate is used in times of high economic growth as a contra-cyclical device to keep the economy from overheating and avoid market bubbles. Further goals of monetary policy are stability of interest rates, of the financial market, of the foreign exchange market. Goals cannot be separated fr