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In paleoanthropology, the recent African origin of modern humans or the " Out of Africa " theory ( OOA) [ a] is the most widely accepted [ 1][ 2][ 3] model of the geographic origin and early migration of anatomically modern humans ( Homo sapiens ). It follows the early expansions of hominins out of Africa, accomplished by Homo erectus and then ...
The official population count of the various ethnic groups in Africa is highly uncertain, both due to limited infrastructure to perform censuses and due to rapid population growth. Some groups have alleged that there is deliberate misreporting in order to give selected ethnicities numerical superiority (as in the case of Nigeria's Hausa, Fulani ...
In the Eulerian specification of a field, the field is represented as a function of position x and time t. For example, the flow velocity is represented by a function. On the other hand, in the Lagrangian specification, individual fluid parcels are followed through time. The fluid parcels are labelled by some (time-independent) vector field x0.
A map of East Africa showing some of the historically active volcanoes (as red triangles) and the Afar Triangle (shaded at the center), which is a so-called triple junction (or triple point) where three plates are pulling away from one another: the Arabian Plate and two parts of the African Plate—the Nubian and Somali—splitting along the East African Rift Zone Main rift faults, plates ...
European archaeology, as well as that of North Africa, is generally divided into the Stone Age (comprising the Lower Paleolithic, the Middle Paleolithic, the Upper Paleolithic, the Mesolithic, and the Neolithic ), the Bronze Age, and the Iron Age. For Africa south of the Sahara, African archaeology is classified in a slightly different way ...
Geography of Africa. Africa is a continent comprising 63 political territories, representing the largest of the great southward projections from the main mass of Earth 's surface. [ 1] Within its regular outline, it comprises an area of 30,368,609 km 2 (11,725,385 sq mi), excluding adjacent islands. Its highest mountain is Kilimanjaro; its ...
USGS map of water use from hydraulic fracturing between 2011 and 2014. One cubic meter of water is 264.172 gallons. [82] [83] The fracturing fluid varies depending on fracturing type desired, and the conditions of specific wells being fractured, and water characteristics. The fluid can be gel, foam, or slickwater-based.
The history of fluid mechanics is a fundamental strand of the history of physics and engineering. The study of the movement of fluids (liquids and gases) and the forces that act upon them dates back to pre-history. The field has undergone a continuous evolution, driven by human dependence on water, meteorological conditions and internal ...