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Rafinesquina Alternata
''Rafinesquina'' is an extinct genus of large brachiopod that existed from the Darriwilian to the Ludlow epoch. The genus was named in honor of polymath Constantine Samuel Rafinesque. Description ''Rafinesquina's'' members were epifaunal, meaning they lived on top of the seafloor, not buried within it, and were suspension feeders. ''Rafinesquina'' normally have a concavo-convex profile, with radiating striae of alternating size which are crossed with finer concentric striae. Their width is usually greater than their length, like most Strophomenids. Members of this genus had shells that grew in increments, with each increment forming a layer of the shell (much like trees do with their rings). In 1982, Gary D. Rosenberg analyzed specimens of '' Rafinesquina alternata'' previously inferred to have lived in a shallow subtidal environment and proposed it could be possible to estimate the total number of days in a lunar month (the period between full moons) during the Late Ordovic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ohio
Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The state's capital and largest city is Columbus, with the Columbus metro area, Greater Cincinnati, and Greater Cleveland being the largest metropolitan areas. Ohio is bordered by Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the west, and Michigan to the northwest. Ohio is historically known as the "Buckeye State" after its Ohio buckeye trees, and Ohioans are also known as "Buckeyes". Its state flag is the only non-rectangular flag of all the U.S. states. Ohio takes its name from the Ohio River, which in turn originated from the Seneca word ''ohiːyo'', meaning "good river", "great river", or "large creek". The state arose from the lands west of the Appalachian Mountai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tree Rings
Dendrochronology (or tree-ring dating) is the scientific method of dating tree rings (also called growth rings) to the exact year they were formed. As well as dating them, this can give data for dendroclimatology, the study of climate and atmospheric conditions during different periods in history from wood. Dendrochronology derives from Ancient Greek (), meaning "tree", (), meaning "time", and (), "the study of". Dendrochronology is useful for determining the precise age of samples, especially those that are too recent for radiocarbon dating, which always produces a range rather than an exact date. However, for a precise date of the death of the tree a full sample to the edge is needed, which most trimmed timber will not provide. It also gives data on the timing of events and rates of change in the environment (most prominently climate) and also in wood found in archaeology or works of art and architecture, such as old panel paintings. It is also used as a check in radiocarb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rafinesquina Insidiosa
''Rafinesquina'' is an extinct genus of large brachiopod that existed from the Darriwilian to the Ludlow epoch. The genus was named in honor of polymath Constantine Samuel Rafinesque. Description ''Rafinesquina's'' members were epifaunal, meaning they lived on top of the seafloor, not buried within it, and were suspension feeders. ''Rafinesquina'' normally have a concavo-convex profile, with radiating striae of alternating size which are crossed with finer concentric striae. Their width is usually greater than their length, like most Strophomenids. Members of this genus had shells that grew in increments, with each increment forming a layer of the shell (much like trees do with their rings). In 1982, Gary D. Rosenberg analyzed specimens of '' Rafinesquina alternata'' previously inferred to have lived in a shallow subtidal environment and proposed it could be possible to estimate the total number of days in a lunar month (the period between full moons) during the Late Ordovi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rafinesquina Deltoidea
''Rafinesquina'' is an extinct genus of large brachiopod that existed from the Darriwilian to the Ludlow epoch. The genus was named in honor of polymath Constantine Samuel Rafinesque. Description ''Rafinesquina's'' members were epifaunal, meaning they lived on top of the seafloor, not buried within it, and were suspension feeders. ''Rafinesquina'' normally have a concavo-convex profile, with radiating striae of alternating size which are crossed with finer concentric striae. Their width is usually greater than their length, like most Strophomenids. Members of this genus had shells that grew in increments, with each increment forming a layer of the shell (much like trees do with their rings). In 1982, Gary D. Rosenberg analyzed specimens of '' Rafinesquina alternata'' previously inferred to have lived in a shallow subtidal environment and proposed it could be possible to estimate the total number of days in a lunar month (the period between full moons) during the Late Ordovic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rafinesquina Delicata
''Rafinesquina'' is an extinct genus of large brachiopod that existed from the Darriwilian to the Ludlow epoch. The genus was named in honor of polymath Constantine Samuel Rafinesque. Description ''Rafinesquina's'' members were epifaunal, meaning they lived on top of the seafloor, not buried within it, and were suspension feeders. ''Rafinesquina'' normally have a concavo-convex profile, with radiating striae of alternating size which are crossed with finer concentric striae. Their width is usually greater than their length, like most Strophomenids. Members of this genus had shells that grew in increments, with each increment forming a layer of the shell (much like trees do with their rings). In 1982, Gary D. Rosenberg analyzed specimens of '' Rafinesquina alternata'' previously inferred to have lived in a shallow subtidal environment and proposed it could be possible to estimate the total number of days in a lunar month (the period between full moons) during the Late Ordovic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rafinesquina Declivis
''Rafinesquina'' is an extinct genus of large brachiopod that existed from the Darriwilian to the Ludlow epoch. The genus was named in honor of polymath Constantine Samuel Rafinesque. Description ''Rafinesquina's'' members were epifaunal, meaning they lived on top of the seafloor, not buried within it, and were suspension feeders. ''Rafinesquina'' normally have a concavo-convex profile, with radiating striae of alternating size which are crossed with finer concentric striae. Their width is usually greater than their length, like most Strophomenids. Members of this genus had shells that grew in increments, with each increment forming a layer of the shell (much like trees do with their rings). In 1982, Gary D. Rosenberg analyzed specimens of '' Rafinesquina alternata'' previously inferred to have lived in a shallow subtidal environment and proposed it could be possible to estimate the total number of days in a lunar month (the period between full moons) during the Late Ordovic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area of , about 30% of Earth's total land area and 8.7% of Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilizations. Its 4.7 billion people constitute roughly 60% of the world's population. In general terms, Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. The border of Asia with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. It is somewhat arbitrary and has moved since its first conception in classical antiquity. The division of Eurasia into two continents reflects East–West cultural, linguistic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia and it is located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. Comprising the westernmost peninsulas of Eurasia, it shares the continental landmass of Afro-Eurasia with both Africa and Asia. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south and Asia to the east. Europe is commonly considered to be Boundaries between the continents of Earth#Asia and Europe, separated from Asia by the drainage divide, watershed of the Ural Mountains, the Ural (river), Ural River, the Caspian Sea, the Greater Caucasus, the Black Sea and the waterways of the Turkish Straits. "Europe" (pp. 68–69); "Asia" (pp. 90–91): "A commonly accepted division between Asia and E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Americas
The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with their associated islands, the Americas cover 8% of Earth's total surface area and 28.4% of its land area. The topography is dominated by the American Cordillera, a long chain of mountains that runs the length of the west coast. The flatter eastern side of the Americas is dominated by large river basins, such as the Amazon, St. Lawrence River–Great Lakes basin, Mississippi, and La Plata. Since the Americas extend from north to south, the climate and ecology vary widely, from the arctic tundra of Northern Canada, Greenland, and Alaska, to the tropical rain forests in Central America and South America. Humans first settled the Americas from Asia between 42,000 and 17,000 years ago. A second migration of Na-Dene speakers followed later ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Ordovician
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cambrian Pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Full Moon
The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective. This occurs when Earth is located between the Sun and the Moon (when the ecliptic coordinate system, ecliptic longitudes of the Sun and Moon opposition (astronomy), differ by 180°). This means that the lunar hemisphere facing Earth—the near side of the Moon, near side—is completely sunlit and appears as an approximately circular disk. The full moon occurs roughly once a month. The time interval between a full moon and the next repetition of the same phase, a Lunar month#Synodic month, synodic month, averages about 29.53 days. Therefore, in those lunar calendars in which each month begins on the day of the new moon, the full moon falls on either the 14th or 15th day of the lunar month. Because a calendar month consists of a Natural number, whole number of days, a month in a lunar calendar may be either 29 or 30 days long. Characteristics A full moon is often thought of as an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Month
In lunar calendars, a lunar month is the time between two successive syzygies of the same type: new moons or full moons. The precise definition varies, especially for the beginning of the month. Variations In Shona, Middle Eastern, and European traditions, the month starts when the young crescent moon first becomes visible, at evening, after conjunction with the Sun one or two days before that evening (e.g., in the Islamic calendar). In ancient Egypt, the lunar month began on the day when the waning moon could no longer be seen just before sunrise. Others run from full moon to full moon. Yet others use calculation, of varying degrees of sophistication, for example, the Hebrew calendar or the ecclesiastical lunar calendar. Calendars count integer days, so months may be 29 or 30 days in length, in some regular or irregular sequence. Lunar cycles are prominent, and calculated with great precision, in the ancient Hindu Panchangam calendar, widely used in the Indian subcontin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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