1.
Eastern Desert
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The Eastern Desert is the section of Sahara Desert east of the Nile River, between the river and the Red Sea. It extends from Egypt in the north to Eritrea in the south, other notable ecological areas are Wadi Gamal National Park and Gebel Elba. The Eastern Desert is a setting for safaris and other excursions. Libyan/Western Desert Geography of Egypt Anthony the Great National Parks of Egypt
2.
NASA World Wind
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World Wind is an open-source virtual globe first developed by NASA in 2003 for use on personal computers and then further developed in concert with the open source community since 2004. As of 2017 a web based version of World Wind is available online, the original version relied on. NET Framework, which ran only on Microsoft Windows. The SDK includes a suite of basic demos, available at goworldwind. org, the World Wind Java version was awarded NASA Software of the Year in November 2009. The program overlays NASA and USGS satellite imagery, aerial photography, topographic maps, Keyhole Markup Language, though widely available since 2003, World Wind was released with the NASA Open Source Agreement license in 2004. The latest Java-based version, was released in December 2016, as of 2015 a web based version of World Wind is under development and available online. An Android version is also available, the previous. NET-based version was an application with an extensive suite of plugins. Apart from the Earth there are worlds, Moon, Mars, Venus, Jupiter. Users could interact with the planet by rotating it, tilting the view. Five million place names, political boundaries, latitude/longitude lines, World Wind. NET provided the ability to browse maps and geospatial data on the internet using the OGCs WMS servers, import ESRI shapefiles and kml/kmz files. This is an example of how World Wind allows anyone to deliver their data, other features of World Wind. NET included support for. X models and advanced visual effects such as atmospheric scattering or sun shading. The resolution inside the US is high enough to discern individual buildings, houses, cars. The resolution outside the US is at least 15 meters per pixel, Microsoft has allowed World Wind to incorporate Virtual Earth high resolution data for non-commercial use. World Wind uses digital elevation model data collected by NASAs Shuttle Radar Topography Mission, National Elevation Dataset and this means one can view topographic features such as the Grand Canyon or Mount Everest in three dimensions. In addition, WW has bathymetry data which allows users to see ocean features, such as trenches and ridges, in 3D. Many people using the applications are adding their own data and are making them available through various sources, such as the World Wind Central or blogs mentioned in the link section below. All images and movies created with World Wind using Blue Marble, Landsat, or USGS public domain data can be modified, re-distributed. World Wind can be expanded by using one of many add-ons - small extensions that add new functionality to the program, plug-in developers can add features to World Wind without changing the programs source code. The original recipe for World Wind was restricted to Windows, relying on the. NET libraries, a new SDK version has been developed in Java with JOGL referred to as World Wind Java
3.
World Wide Fund for Nature
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It was formerly named the World Wildlife Fund, which remains its official name in Canada and the United States. It is the worlds largest conservation organization with five million supporters worldwide, working in more than 100 countries, supporting around 1,300 conservation. WWF is a foundation, with 55% of funding from individuals and bequests, 19% from government sources, the groups mission is to stop the degradation of the planet’s natural environment and to build a future in which humans live in harmony with nature. Currently, much of its work concentrates on the conservation of three biomes that contain most of the biodiversity, oceans and coasts, forests. Among other issues, it is concerned with endangered species, sustainable production of commodities. The Conservation Foundation, a precursor to WWF, was founded in 1947 by Fairfield Osborn in New York City in support of capitalism-friendly ecological practices. The advisory council included leading scientists such as Charles Sutherland Elton, G Evelyn Hutchinson, Aldo Leopold, Carl Sauer, and Paul Sears. It supported much of the work cited by Rachel Carsons Silent Spring, including that of John L. George, Roger Hale, Robert Rudd. In 1990, the Conservation Foundation was merged into WWF, after becoming an affiliate of WWF in 1985, the organization now known as the Conservation Foundation in the United States is the former Forest Foundation of DuPage County. The idea for a fund on behalf of endangered animals was initially proposed by Victor Stolan to Sir Julian Huxley in response to articles he published in the British newspaper The Observer, nicholson thought up the name of the organization. WWF was conceived on 29 April 1961, under the name of World Wildlife Fund, godfrey A. Rockefeller also played an important role in its creation, assembling the first staff. For sending experts to danger spots and training, making it all possible that their needs are met before it is too late. WWF has set up offices and operations around the world, the organization also began to run its own conservation projects and campaigns, and by the 1980s started to take a more strategic approach to its conservation activities. In 1986, the changed its name to World Wide Fund for Nature. However, it continued at that time to operate under the name in the United States. We shant save all we should like to, but we shall save a great deal more than if we had never tried, – Sir Peter Scott In 1996, the organization obtained general consultative status from UNESCO. WWFs giant panda logo originated from a panda named Chi Chi that had transferred from Beijing Zoo to London Zoo in 1958. The logo was founded by Young in 1966, the organization also needed an animal that would have an impact in black and white printing
4.
NASA
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President Dwight D. Eisenhower established NASA in 1958 with a distinctly civilian orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29,1958, disestablishing NASAs predecessor, the new agency became operational on October 1,1958. Since that time, most US space exploration efforts have led by NASA, including the Apollo Moon landing missions, the Skylab space station. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle, the agency is also responsible for the Launch Services Program which provides oversight of launch operations and countdown management for unmanned NASA launches. NASA shares data with various national and international such as from the Greenhouse Gases Observing Satellite. Since 2011, NASA has been criticized for low cost efficiency, from 1946, the National Advisory Committee for Aeronautics had been experimenting with rocket planes such as the supersonic Bell X-1. In the early 1950s, there was challenge to launch a satellite for the International Geophysical Year. An effort for this was the American Project Vanguard, after the Soviet launch of the worlds first artificial satellite on October 4,1957, the attention of the United States turned toward its own fledgling space efforts. This led to an agreement that a new federal agency based on NACA was needed to conduct all non-military activity in space. The Advanced Research Projects Agency was created in February 1958 to develop technology for military application. On July 29,1958, Eisenhower signed the National Aeronautics and Space Act, a NASA seal was approved by President Eisenhower in 1959. Elements of the Army Ballistic Missile Agency and the United States Naval Research Laboratory were incorporated into NASA, earlier research efforts within the US Air Force and many of ARPAs early space programs were also transferred to NASA. In December 1958, NASA gained control of the Jet Propulsion Laboratory, NASA has conducted many manned and unmanned spaceflight programs throughout its history. Some missions include both manned and unmanned aspects, such as the Galileo probe, which was deployed by astronauts in Earth orbit before being sent unmanned to Jupiter, the experimental rocket-powered aircraft programs started by NACA were extended by NASA as support for manned spaceflight. This was followed by a space capsule program, and in turn by a two-man capsule program. This goal was met in 1969 by the Apollo program, however, reduction of the perceived threat and changing political priorities almost immediately caused the termination of most of these plans. NASA turned its attention to an Apollo-derived temporary space laboratory, to date, NASA has launched a total of 166 manned space missions on rockets, and thirteen X-15 rocket flights above the USAF definition of spaceflight altitude,260,000 feet. The X-15 was an NACA experimental rocket-powered hypersonic research aircraft, developed in conjunction with the US Air Force, the design featured a slender fuselage with fairings along the side containing fuel and early computerized control systems
5.
Desert
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A desert is a barren area of land where little precipitation occurs and consequently living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to the processes of denudation, about one third of the land surface of the world is arid or semi-arid. This includes much of the regions where little precipitation occurs. Deserts can be classified by the amount of precipitation falls, by the temperature that prevails. Deserts are formed by weathering processes as large variations in temperature between day and night put strains on the rocks which consequently break in pieces, although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods. Rain falling on hot rocks can cause them to shatter and the resulting fragments and this picks up particles of sand and dust and wafts them aloft in sand or dust storms. Wind-blown sand grains striking any solid object in their path can abrade the surface, rocks are smoothed down, and the wind sorts sand into uniform deposits. The grains end up as level sheets of sand or are piled high in billowing sand dunes, other deserts are flat, stony plains where all the fine material has been blown away and the surface consists of a mosaic of smooth stones. These areas are known as desert pavements and little further erosion takes place, other desert features include rock outcrops, exposed bedrock and clays once deposited by flowing water. Temporary lakes may form and salt pans may be left when waters evaporate, there may be underground sources of water in the form of springs and seepages from aquifers. Where these are found, oases can occur, plants and animals living in the desert need special adaptations to survive in the harsh environment. Plants tend to be tough and wiry with small or no leaves, water-resistant cuticles, some annual plants germinate, bloom and die in the course of a few weeks after rainfall while other long-lived plants survive for years and have deep root systems able to tap underground moisture. Animals need to cool and find enough food and water to survive. Many are nocturnal and stay in the shade or underground during the heat of the day and they tend to be efficient at conserving water, extracting most of their needs from their food and concentrating their urine. Some animals remain in a state of dormancy for long periods and they then reproduce rapidly while conditions are favorable before returning to dormancy. People have struggled to live in deserts and the surrounding lands for millennia. Nomads have moved their flocks and herds to wherever grazing is available, the cultivation of semi-arid regions encourages erosion of soil and is one of the causes of increased desertification. Many trade routes have been forged across deserts, especially across the Sahara Desert, large numbers of slaves were also taken northwards across the Sahara
6.
Yemen
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Yemen, officially known as the Republic of Yemen, is an Arab country in Western Asia, occupying South Arabia, the southern end of the Arabian Peninsula. Yemen is the second-largest country in the peninsula, occupying 527,970 km2, the coastline stretches for about 2,000 km. It is bordered by Saudi Arabia to the north, the Red Sea to the west, the Gulf of Aden and Arabian Sea to the south, although Yemens constitutionally stated capital is the city of Sanaa, the city has been under rebel control since February 2015. Because of this, Yemens capital has been relocated to the port city of Aden. Yemens territory includes more than 200 islands, the largest of these is Socotra, Yemen was the home of the Sabaeans, a trading state that flourished for over a thousand years and probably also included parts of modern-day Ethiopia and Eritrea. In 275 AD, the region came under the rule of the later Jewish-influenced Himyarite Kingdom, Christianity arrived in the fourth century, whereas Judaism and local paganism were already established. Islam spread quickly in the century and Yemenite troops were crucial in the expansion of the early Islamic conquests. Administration of Yemen has long been notoriously difficult, several dynasties emerged from the ninth to 16th centuries, the Rasulid dynasty being the strongest and most prosperous. The country was divided between the Ottoman and British empires in the twentieth century. The Zaydi Mutawakkilite Kingdom of Yemen was established after World War I in North Yemen before the creation of the Yemen Arab Republic in 1962, South Yemen remained a British protectorate known as the Aden Protectorate until 1967 when it became an independent state and later, a Marxist state. The two Yemeni states united to form the modern republic of Yemen in 1990, Yemen is a developing country, and the poorest country in the Middle East. Under the rule of President Ali Abdullah Saleh, Yemen was described as a kleptocracy, according to the 2009 international corruption Perception Index by Transparency International, Yemen ranked 164 out of 182 countries surveyed. President Saleh stepped down and the powers of the presidency were transferred to Vice President Abd Rabbuh Mansur Hadi, the transitional process was disrupted by conflicts between the Houthis and al-Islah, as well as the al-Qaeda insurgency. In September 2014, the Houthis took over Sanaa, later declaring themselves in control of the government in a coup détat, since then, a Saudi-led intervention has taken place, however, it could not stop the civil war. Instead, the Saudis and the others have destroyed some hospitals, schools and homes, Yemen was mentioned in Old South Arabian inscriptions as Yamnat. In Arabic literature, the term includes much greater territory than that of the republic of Yemen. It stretches from the northern Asir Region in southwestern Saudi Arabia to Dhofar Governorate in southern Oman, one etymology derives Yemen from yumn, meaning felicity, as much of the country is fertile. The Romans called it Arabia Felix, as opposed to Arabia Deserta, al-Yaman significantly plays on the notion of the land to the right, when in Mecca facing the dawn, complementary to Al-Sham, the Land to the Left, referring to the Levant
7.
Persian Gulf
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The Persian Gulf is a mediterranean sea in Western Asia. The body of water is an extension of the Indian Ocean through the Strait of Hormuz, the Shatt al-Arab river delta forms the northwest shoreline. The Persian Gulf was a battlefield of the 1980–1988 Iran–Iraq War and it is the namesake of the 1991 Gulf War, the largely air- and land-based conflict that followed Iraqs invasion of Kuwait. The gulf has many fishing grounds, extensive coral reefs, and abundant pearl oysters, the body of water is historically and internationally known as the Persian Gulf. Some Arab governments refer to it as the Arabian Gulf or The Gulf, the name Gulf of Iran is used by the International Hydrographic Organization. The Persian Gulf is geologically young, having been formed around 15,000 years ago. Its length is 989 kilometres, with Iran covering most of the northern coast, the Persian Gulf is about 56 km wide at its narrowest, in the Strait of Hormuz. The waters are very shallow, with a maximum depth of 90 metres. Various small islands lie within the Persian Gulf, some of which are the subject of territorial disputes between the states of the region. The International Hydrographic Organization defines the Persian Gulfs southern limit as The Northwestern limit of Gulf of Oman and this limit is defined as A line joining Ràs Limah on the coast of Arabia and Ràs al Kuh on the coast of Iran. The Persian Gulf and its areas are the worlds largest single source of crude oil. Safaniya Oil Field, the worlds largest offshore oilfield, is located in the Persian Gulf, large gas finds have also been made, with Qatar and Iran sharing a giant field across the territorial median line. Using this gas, Qatar has built up a substantial liquefied natural gas, the oil-rich countries that have a coastline on the Persian Gulf are referred to as the Persian Gulf States. In 550 BC, the Achaemenid Empire established the first ancient empire in Persis, consequently, in the Greek sources, the body of water that bordered this province came to be known as the Persian Gulf. In the travel account of Pythagoras, several chapters are related to description of his travels accompanied by the Achaemenid king Darius the Great, to Susa and Persepolis, and the area is described. This water channel separates the Iran Plateau from the Arabia Plate, has enjoyed an Iranian Identity since at least 2200 years ago. Before being given its present name, the Persian Gulf was called many different names, the classical Greek writers, like Herodotus, called it the Red Sea. In Babylonian texts, it was known as the sea above Akkad, the name of the gulf, historically and internationally known as the Persian Gulf after the land of Persia, has been disputed by some Arab countries since the 1960s
8.
Oman
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Oman, officially the Sultanate of Oman, is an Arab country on the southeastern coast of the Arabian Peninsula. The coast is formed by the Arabian Sea on the southeast, the Madha and Musandam exclaves are surrounded by the UAE on their land borders, with the Strait of Hormuz and Gulf of Oman forming Musandams coastal boundaries. From the late 17th century, the Omani Sultanate was an empire, vying with Portugal and Britain for influence in the Persian Gulf. At its peak in the 19th century, Omani influence or control extended across the Strait of Hormuz to modern-day Iran and Pakistan, as its power declined in the 20th century, the sultanate came under the influence of the United Kingdom. Historically, Muscat was the trading port of the Persian Gulf region. Muscat was also among the most important trading ports of the Indian Ocean, the Sultan Qaboos bin Said al Said has been the hereditary leader of the country since 1970. Sultan Qaboos is the current ruler in the Middle East. Oman has modest oil reserves, ranking 25th globally, nevertheless, in 2010 the UNDP ranked Oman as the most improved nation in the world in terms of development during the preceding 40 years. A significant portion of its economy is tourism and trade of fish, dates and this sets it apart from its neighbors solely oil-dependent economies. Oman is categorized as an economy and ranks as the 74th most peaceful country in the world according to the Global Peace Index. Two optically stimulated luminescence age estimates place the Arabian Nubian Complex at 106,000 years old and this supports the proposition that early human populations moved from Africa into Arabia during the Late Pleistocene. Dereaze, located in the city of Ibri, is the oldest known settlement in the area. Archaeological remains have been discovered here from the Stone Age and the Bronze Age, findings have included stone implements, animal bones, shells and fire hearths, with the latter dating back to 7615 BC as the oldest signs of human settlement in the area. Other discoveries include hand-molded pottery bearing distinguishing pre-Bronze Age marks, heavy flint implements, pointed tools, sumerian tablets refer to a country called Magan or Makan, a name believed to refer to Omans ancient copper mines. Mazoon, another used for the region, is derived from the word muzn. The present-day name of the country, Oman, is believed to originate from the Arab tribes who migrated to its territory from the Uman region of Yemen. Many such tribes settled in Oman, making a living by fishing, herding or stock breeding, from the 6th century BC to the arrival of Islam in the 7th century AD, Oman was controlled and/or influenced by three Persian dynasties, the Achaemenids, Parthians and Sassanids. A few scholars believe that in the 6th century BC, the Achaemenids exerted a strong degree of control over the Omani peninsula, Central Oman has its own indigenous so-called Late Iron Age cultural assemblage, the Samad al-Shan
9.
Jordan
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Jordan, officially The Hashemite Kingdom of Jordan, is an Arab kingdom in Western Asia, on the East Bank of the Jordan River. Jordan is bordered by Saudi Arabia to the east and south, Iraq to the north-east, Syria to the north, Israel, Palestine and the Dead Sea to the west, Jordan is strategically located at the crossroads of Asia, Africa and Europe. The capital, Amman, is Jordans most populous city as well as the countrys economic, what is now Jordan has been inhabited by humans since the Paleolithic period. Three stable kingdoms emerged there at the end of the Bronze Age, Ammon, Moab, later rulers include the Nabataean Kingdom, the Roman Empire, and the Ottoman Empire. After the Great Arab Revolt against the Ottomans in 1916 during World War I, the Emirate of Transjordan was established in 1921 by the then Emir Abdullah I and became a British protectorate. In 1946, Jordan became an independent state known as The Hashemite Kingdom of Transjordan. Jordan captured the West Bank, which it later lost in 1967, during the 1948 Arab–Israeli War, Jordan is a founding member of the Arab League and the Organisation of Islamic Cooperation, and is one of two Arab states to have signed a peace treaty with Israel. The country is a monarchy, but the king holds wide executive and legislative powers. Jordan is a relatively-small, semi-arid, almost-landlocked country with a population numbering at 9.5 million, Sunni Islam, practiced by around 92% of the population, is the dominant religion in Jordan. It coexists with an indigenous Christian minority, Jordan is considered to be among the safest of Arab countries in the Middle East, and has avoided long-term terrorism and instability. The kingdom is also a refuge to thousands of Iraqi Christians fleeing the Islamic State, while Jordan continues to accept refugees, the recent large influx from Syria placed substantial strain on national resources and infrastructure. Jordan is classified as a country of high human development with a middle income economy. The Jordanian economy, one of the smallest economies in the region, is attractive to foreign investors based upon a skilled workforce, the country is a major tourist destination, and also attracts medical tourism due to its well developed health sector. Nonetheless, a lack of resources, large flow of refugees. Jordan is named after the Jordan River, where Jesus is said to have been baptized, the origin of the rivers name is debated, but the most common explanation is that it derives from the word yarad, found in Hebrew, Aramaic, and other Semitic languages. Others regard the name as having an Indo-Aryan origin, combining the words yor and don, another theory is that it is from the Arabic root word wrd, as in people coming to a major source of water. The name Jordan appears in an ancient Egyptian papyrus called Papyrus Anastasi I, the lands of modern-day Jordan were historically called Transjordan, meaning beyond the Jordan River. The name was Arabized into Al-Urdunn during the Muslim conquest of the Levant, during crusader rule, it was called Oultrejordain
10.
Iraq
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The capital, and largest city, is Baghdad. The main ethnic groups are Arabs and Kurds, others include Assyrians, Turkmen, Shabakis, Yazidis, Armenians, Mandeans, Circassians, around 95% of the countrys 36 million citizens are Muslims, with Christianity, Yarsan, Yezidism, and Mandeanism also present. The official languages of Iraq are Arabic and Kurdish, two major rivers, the Tigris and Euphrates, run south through Iraq and into the Shatt al-Arab near the Persian Gulf. These rivers provide Iraq with significant amounts of fertile land, the region between the Tigris and Euphrates rivers, historically known as Mesopotamia, is often referred to as the cradle of civilisation. It was here that mankind first began to read, write, create laws, the area has been home to successive civilisations since the 6th millennium BC. Iraq was the centre of the Akkadian, Sumerian, Assyrian and it was also part of the Median, Achaemenid, Hellenistic, Parthian, Sassanid, Roman, Rashidun, Umayyad, Abbasid, Ayyubid, Mongol, Safavid, Afsharid, and Ottoman empires. Iraqs modern borders were mostly demarcated in 1920 by the League of Nations when the Ottoman Empire was divided by the Treaty of Sèvres, Iraq was placed under the authority of the United Kingdom as the British Mandate of Mesopotamia. A monarchy was established in 1921 and the Kingdom of Iraq gained independence from Britain in 1932, in 1958, the monarchy was overthrown and the Iraqi Republic created. Iraq was controlled by the Arab Socialist Baath Party from 1968 until 2003, after an invasion by the United States and its allies in 2003, Saddam Husseins Baath Party was removed from power and multi-party parliamentary elections were held in 2005. The American presence in Iraq ended in 2011, but the Iraqi insurgency continued and intensified as fighters from the Syrian Civil War spilled into the country, the Arabic name العراق al-ʿIrāq has been in use since before the 6th century. There are several suggested origins for the name, one dates to the Sumerian city of Uruk and is thus ultimately of Sumerian origin, as Uruk was the Akkadian name for the Sumerian city of Urug, containing the Sumerian word for city, UR. An Arabic folk etymology for the name is rooted, well-watered. During the medieval period, there was a region called ʿIrāq ʿArabī for Lower Mesopotamia and ʿIrāq ʿajamī, for the region now situated in Central and Western Iran. The term historically included the south of the Hamrin Mountains. The term Sawad was also used in early Islamic times for the region of the plain of the Tigris and Euphrates rivers. In English, it is either /ɪˈrɑːk/ or /ɪˈræk/, the American Heritage Dictionary, the pronunciation /aɪˈræk/ is frequently heard in U. S. media. Since approximately 10,000 BC, Iraq was one of centres of a Caucasoid Neolithic culture where agriculture, the following Neolithic period is represented by rectangular houses. At the time of the pre-pottery Neolithic, people used vessels made of stone, gypsum, finds of obsidian tools from Anatolia are evidences of early trade relations
11.
Arabian Peninsula
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The Arabian Peninsula, simplified Arabia is a peninsula of Western Asia situated northeast of Africa on the Arabian plate. From a geological perspective, it is considered a subcontinent of Asia and it is the largest peninsula in the world, at 3,237,500 km2. The Arabian Peninsula consists of the countries Yemen, Oman, Qatar, Bahrain, Kuwait, Saudi Arabia, the Arabian Peninsula plays a critical geopolitical role in the Middle East and the Arab world due to its vast reserves of oil and natural gas. Before the modern era, it was divided into four regions, Hejaz, Najd, Southern Arabia. Hejaz and Najd make up most of Saudi Arabia, Southern Arabia consists of Yemen and some parts of Saudi Arabia and Oman. Eastern Arabia consists of the coastal strip of the Persian Gulf. The most prominent feature of the peninsula is desert, but in the southwest there are mountain ranges, harrat ash Shaam is a large volcanic field that extends from the northwestern Arabian Peninsula into Jordan and southern Syria. The peninsulas constituent countries are Kuwait, Bahrain, Qatar, the island nation of Bahrain lies off the east coast of the peninsula. Six countries form the Gulf Cooperation Council, however, this is a disputed term. The Kingdom of Saudi Arabia covers the part of the peninsula. The majority of the population of the live in Saudi Arabia. The peninsula contains the worlds largest reserves of oil, Saudi Arabia and the UAE are economically the wealthiest in the region. Qatar, a peninsula in the Persian Gulf on the larger peninsula, is home of the Arabic-language television station Al Jazeera. Kuwait, on the border with Iraq, is an important country strategically, though historically lightly populated, political Arabia is noted for a high population growth rate - as the result of both very strong inflows of migrant labor as well as sustained high birth rates. The population tends to be young and heavily skewed gender ratio dominated by males. In many states, the number of South Asians exceeds that of the local citizenry, the four smallest states, which have their entire coastlines on the Persian Gulf, exhibit the worlds most extreme population growth, roughly tripling every 20 years. In 2014, the population of the Arabian Peninsula was 77,983,936. Listed here are the human Y-chromosome DNA haplogroups in Arabia Haplogroup J is the most abundant component in the Arabian peninsula and its two main subclades, show opposite latitudinal gradients in the Middle East
12.
Sand
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Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. It is defined by size, being finer than gravel and coarser than silt, Sand can also refer to a textural class of soil or soil type, i. e. a soil containing more than 85% sand-sized particles by mass. The second most common type of sand is calcium carbonate, for example aragonite, for example, it is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years like the Caribbean. Sand is a non renewable resource over human timescales, and sand suitable for making concrete is in high demand, in terms of particle size as used by geologists, sand particles range in diameter from 0.0625 mm to 2 mm. An individual particle in this size is termed a sand grain. Sand grains are between gravel and silt, a 1953 engineering standard published by the American Association of State Highway and Transportation Officials set the minimum sand size at 0.074 mm. A1938 specification of the United States Department of Agriculture was 0.05 mm. Sand feels gritty when rubbed between the fingers. ISO14688 grades sands as fine, medium and coarse with ranges 0.063 mm to 0.2 mm to 0.63 mm to 2.0 mm. In the United States, sand is commonly divided into five sub-categories based on size, very fine sand, fine sand, medium sand, coarse sand, and very coarse sand. These sizes are based on the Krumbein phi scale, where size in Φ = -log2D, on this scale, for sand the value of Φ varies from −1 to +4, with the divisions between sub-categories at whole numbers. The composition of sand is highly variable, depending on the local rock sources. The gypsum sand dunes of the White Sands National Monument in New Mexico are famous for their bright, arkose is a sand or sandstone with considerable feldspar content, derived from weathering and erosion of a granitic rock outcrop. Some sands contain magnetite, chlorite, glauconite or gypsum, Sands rich in magnetite are dark to black in color, as are sands derived from volcanic basalts and obsidian. Chlorite-glauconite bearing sands are typically green in color, as are sands derived from basaltic with a high olivine content, many sands, especially those found extensively in Southern Europe, have iron impurities within the quartz crystals of the sand, giving a deep yellow color. Sand deposits in some areas contain garnets and other resistant minerals, the study of individual grains can reveal much historical information as to the origin and kind of transport of the grain. Quartz sand that is weathered from granite or gneiss quartz crystals will be angular. It is called grus in geology or sharp sand in the trade where it is preferred for concrete. Sand that is transported long distances by water or wind will be rounded, people who collect sand as a hobby are known as arenophiles
