|
African Cattle
Sanga cattle is the collective name for indigenous cattle of some regions in Africa. They are sometimes identified as a subspecies with the scientific name ''Bos taurus africanus''. Their history of domestication and their origins in relation to taurine cattle, zebu cattle (indicine), and native African varieties of the ancestral aurochs are a matter of debate. "African taurine", "sanga", "zenga", "sheko", "African indicine" are all sub-groups of Sanga cattle. Genetic signatures and classification A relatively complete survey on the many breeds of Sanga cattle is Kim ''et al.'' 2020. Admixture analysis from this paper groups Sanga cattle under the following taxonomy: * African taurine (N'Dama, Muturu) * African humped cattle ** African indicine (Mursi) ** African zenga (Fogera, Horro) ** African sanga (Ankole) ** Sheko In the analyses cited by Kim, African taurine (''Bos taurus taurus'') first split from Eurasian taurine. A group of Asian indicine cattle ("Zebu", ''Bos taurus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unavailable Name
In reliability engineering, the term availability has the following meanings: * The degree to which a system, subsystem or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at an unknown, ''i.e.'' a random, time. * The probability that an item will operate satisfactorily at a given point in time when used under stated conditions in an ideal support environment. Normally high availability systems might be specified as 99.98%, 99.999% or 99.9996%. The converse, unavailability, is 1 minus the availability. Representation The simplest representation of availability (''A'') is a ratio of the expected value of the uptime of a system to the aggregate of the expected values of up and down time (that results in the "total amount of time" ''C'' of the observation window) : A = \frac = \frac Another equation for availability (''A'') is a ratio of the Mean Time To Failure (MTTF) and Mean Time Between Failure (MTBF), or : ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ResearchGate
ResearchGate is a European commercial social networking site for scientists and researchers to share papers, ask and answer questions, and find collaborators. According to a 2014 study by ''Nature'' and a 2016 article in ''Times Higher Education'', it is the largest academic social network in terms of active users, although other services have more registered users, and a 2015–2016 survey suggests that almost as many academics have Google Scholar profiles. While reading articles does not require registration, people who wish to become site members need to have an email address at a recognized institution or to be manually confirmed as a published researcher in order to sign up for an account. Articles are free to read by visitors, however additional features (such as job postings or advertisements) are accessible only as a paid subscription. Members of the site each have a user profile and can upload research output including papers, data, chapters, negative results, patents, r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Africa
North Africa (sometimes Northern Africa) is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region. However, it is sometimes defined as stretching from the Atlantic shores of the Western Sahara in the west, to Egypt and Sudan's Red Sea coast in the east. The most common definition for the region's boundaries includes Algeria, Egypt, Libya, Morocco, Tunisia, and Western Sahara, the territory territorial dispute, disputed between Morocco and the list of states with limited recognition, partially recognized Sahrawi Arab Democratic Republic. The United Nations’ definition includes all these countries as well as Sudan. The African Union defines the region similarly, only differing from the UN in excluding the Sudan and including Mauritania. The Sahel, south of the Sahara, Sahara Desert, can be considered as the southern boundary of North Africa. North Africa includes the Spanish cities of Ceuta and Melilla, and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial DNA
Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the DNA contained in a eukaryotic cell; most of the DNA is in the cell nucleus, and, in plants and algae, the DNA also is found in plastids, such as chloroplasts. Mitochondrial DNA is responsible for coding of 13 essential subunits of the complex oxidative phosphorylation (OXPHOS) system which has a role in cellular energy conversion. Human mitochondrial DNA was the first significant part of the human genome to be sequenced. This sequencing revealed that human mtDNA has 16,569 base pairs and encodes 13 proteins. As in other vertebrates, the human mitochondrial genetic code differs slightly from nuclear DNA. Since animal mtDNA evolves faster than nuclear genetic markers, it represents a mainstay of phylogenetics and evolutionary biology. It als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wadi Howar
Wadi Howar (Wadi Howa or Yellow Nile) is a wadi in Sudan and Chad. Geography Originating in the Ennedi Region of Chad ''Wadi Howar'' runs through the Sudanese states of North Darfur and Northern to join the Nile north of the great bend opposite Old Dongola. Stretching over 1100 km in west–east direction across the southern fringes of the Libyan Desert, it ordinarily receives 25 mm of rainfall per year. Holocene period ''Wadi Howar'' is the remnant of the ancient ''Yellow Nile'', a tributary of the Nile during the African humid period from about 9500 to 4500 years ago. At that time, savanna fauna and cattle herders occupied this region and the southern edge of the Sahara was some further north than it is today. When the Sahara underwent desertification between 6000 and 4000 years ago, the wadi Wadi ( ; ) is a river valley or a wet (ephemerality, ephemeral) Stream bed, riverbed that contains water only when heavy rain occurs. Wadis are located on gently ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
India
India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since 2023; and, since its independence in 1947, the world's most populous democracy. Bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast, it shares land borders with Pakistan to the west; China, Nepal, and Bhutan to the north; and Bangladesh and Myanmar to the east. In the Indian Ocean, India is near Sri Lanka and the Maldives; its Andaman and Nicobar Islands share a maritime border with Thailand, Myanmar, and Indonesia. Modern humans arrived on the Indian subcontinent from Africa no later than 55,000 years ago., "Y-Chromosome and Mt-DNA data support the colonization of South Asia by modern humans originating in Africa. ... Coalescence dates for most non-European populations averag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northeast Africa
Northeast Africa, or Northeastern Africa, or Northern East Africa as it was known in the past, encompasses the countries of Africa situated in and around the Red Sea. The region is intermediate between North Africa and East Africa, and encompasses the Horn of Africa (Djibouti, Eritrea, Ethiopia, and Somalia), as well as Egypt and Sudan, and in addition to, although rarely, South Sudan. The region has a very long history of habitation with fossil finds from the early hominids to modern human and is one of the most culturally and linguistically diverse regions of the world, being the home to many civilizations and located on an important trade route that connects multiple continents; Gamal Abdel Nasser, the second president of Egypt (which is the most northeastern African country) once described it as "the crossroads of the world, the thoroughfare of its traders and passageway of its armies." See also * East Africa * Horn of Africa * North Africa * Ancient Egypt * Ancient Libya * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bir Kiseiba
Bir Kiseiba is a Neolithic archaeological site in Egypt, dating from approximately 11,000–5,000 BP, that lies approximately 250 km west of the Nile in Lower Nubia. Excavated by Fred Wendorf, Romauld Schild, and Angela Close, Bir Kiseiba, along with Nabta Playa, has some of the earliest evidence for food production, permanent settlement, and more diverse technologies as compared to sites from the Late Pleistocene. Wendorf and associates argue that cattle and pottery were here as early as any other place in Africa, although this assertion has been challenged. Archaeology Most of the studies in the Bir Kiseiba region relate to the beginning of the Holocene when there was a wet period from about 11–10,000 BP until 5000 BP. There were two digging seasons at Bir Kiseiba, one in 1979 and the second in 1980. A total of 13 localities were excavated, scattered among four dry lakes or playas in the Bir Kiseiba region. Occupations from throughout the Early H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nabta Playa
Nabta Playa was once a large endorheic basin in the Nubian Desert, located approximately 800 kilometers south of modern-day Cairo or about 100 kilometers west of Abu Simbel in southern Egypt, 22.51° north, 30.73° east. Today the region is characterized by numerous archaeological sites. The Nabta Playa archaeological site, one of the earliest of the Egyptian Neolithic Period, is dated to circa 7500 BC. Early history Although today the western Egyptian desert is totally dry, this was not always the case. There is good evidence that there were several humid periods in the past (when up to 500 mm of rain would fall per year), the most recent one during the last interglacial and early last glaciation periods which stretched between 130,000 and 70,000 years ago. During this time, the area was a savanna and supported numerous animals such as extinct buffalo and large giraffes, varieties of antelope and gazelle. Beginning around the 10th millennium BC, this re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Before Present
Before Present (BP) or "years before present (YBP)" is a time scale used mainly in archaeology, geology, and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Because the "present" time changes, standard practice is to use 1January 1950 as the commencement date (epoch) of the age scale, with 1950 being labelled as the "standard year". The abbreviation "BP" has been interpreted retrospectively as "Before Physics", which refers to the time before nuclear weapons testing artificially altered the proportion of the carbon isotopes in the atmosphere, which scientists must account for when using radiocarbon dating for dates of origin that may fall after this year. In a convention that is not always observed, many sources restrict the use of BP dates to those produced with radiocarbon dating; the alternative notation "RCYBP" stands for the explicit "radio carbon years before present". Usage The BP scale is s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acacus Mountains
The Acacus Mountains or Tadrart Akakus ( / ALA-LC: ''Tadrārt Akākūs'') form a mountain range in the desert of the Ghat District in western Libya, part of the Sahara. They are situated east of the city of Ghat, Libya, and stretch north from the border with Algeria, about . The area has a particularly rich array of prehistoric rock art. History Etymology ''Tadrart'' is the feminine form of "mountain" in the Berber languages (masculine: ''adrar''). Archaeology The Acacus Mountains were occupied by hunter-gatherers continuously in the Holocene despite fluctuating climate in the African Humid Period. These sites have been important in understanding food processing and mobility as people adapted to climate variation. Animal domestication as part of the African Neolithic was introduced in this region by around 7000 BP, and pastoralism and foraging were the primary subsistence strategies of people in this region, not agriculture. Sites in this region have been split into three main ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorian Garrick
Dorian may refer to: Ancient Greece * Dorians, one of the main ethnic divisions of ancient Greeks * Doric Greek, or Dorian, the dialect spoken by the Dorians Art and entertainment Films * ''Dorian'' (film), the Canadian title of the 2004 film ''Pact with the Devil'' * '' Dorian Blues'', a 2004 film Literature * ''Dorian, an Imitation'', a 2002 novel by Will Self * ''Dorian'', a 1921 novel by Nephi Anderson * ''Dorian'', a 2022 play by Darryl Pinckney and Robert Wilson Music * Dorians (band), from Armenia * Dorian (Spanish band), a Spanish band * Dorian mode, various musical modes * Dorian Recordings, a label noted for early music recordings * Toccata and Fugue in D minor, BWV 538, or "Dorian", an organ piece by Johann Sebastian Bach * Ukrainian Dorian scale, a musical mode * "Dorian," a song by Demons and Wizards on their album '' Touched by the Crimson King'' People * Dorian (name), a given name (includes a list of people with the name) * Dorian (rapper) (born 1984), Amer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
