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Lentoid
Lentoid is a geometric shape of a three-dimensional body, best described as a circle viewed from one direction and a convex lens viewed from every orthogonal direction. It has no strict mathematical definition, but may be described as the volume enclosed within overlapping paraboloids. The term is most often used in describing jewelry and cellular phenomena in microbiology. In history Since ancient times, the lentoid shape has been used to fashion jewelry and seals for identification made from a variety of gemstones and metals. In Minoan Crete, for example, Minoan seals have been found with complex carving on lentoid stones. The lentoid shape was one of the most commonly recovered seal shapes from Minoan Knossos on Crete dating to the Bronze Age, as evidenced by the finds at that Bronze Age palace.C. Michael Hogan''Knossos fieldnotes'', Modern Antiquarian (2007)/ref> Gallery File:Agate lentoid seal MET DP141655 DP141657.jpg, Lentoid Minoan seal in agate: seal and impress ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lentoid
Lentoid is a geometric shape of a three-dimensional body, best described as a circle viewed from one direction and a convex lens viewed from every orthogonal direction. It has no strict mathematical definition, but may be described as the volume enclosed within overlapping paraboloids. The term is most often used in describing jewelry and cellular phenomena in microbiology. In history Since ancient times, the lentoid shape has been used to fashion jewelry and seals for identification made from a variety of gemstones and metals. In Minoan Crete, for example, Minoan seals have been found with complex carving on lentoid stones. The lentoid shape was one of the most commonly recovered seal shapes from Minoan Knossos on Crete dating to the Bronze Age, as evidenced by the finds at that Bronze Age palace.C. Michael Hogan''Knossos fieldnotes'', Modern Antiquarian (2007)/ref> Gallery File:Agate lentoid seal MET DP141655 DP141657.jpg, Lentoid Minoan seal in agate: seal and impress ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oblate Spheroid
A spheroid, also known as an ellipsoid of revolution or rotational ellipsoid, is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters. A spheroid has circular symmetry. If the ellipse is rotated about its major axis, the result is a ''prolate spheroid'', elongated like a rugby ball. The American football is similar but has a pointier end than a spheroid could. If the ellipse is rotated about its minor axis, the result is an ''oblate spheroid'', flattened like a lentil or a plain M&M. If the generating ellipse is a circle, the result is a sphere. Due to the combined effects of gravity and rotation, the figure of the Earth (and of all planets) is not quite a sphere, but instead is slightly flattened in the direction of its axis of rotation. For that reason, in cartography and geodesy the Earth is often approximated by an oblate spheroid, known as the reference ellipsoid, instead of a spher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spheroid
A spheroid, also known as an ellipsoid of revolution or rotational ellipsoid, is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters. A spheroid has circular symmetry. If the ellipse is rotated about its major axis, the result is a ''prolate spheroid'', elongated like a rugby ball. The American football is similar but has a pointier end than a spheroid could. If the ellipse is rotated about its minor axis, the result is an ''oblate spheroid'', flattened like a lentil or a plain M&M. If the generating ellipse is a circle, the result is a sphere. Due to the combined effects of gravity and rotation, the figure of the Earth (and of all planets) is not quite a sphere, but instead is slightly flattened in the direction of its axis of rotation. For that reason, in cartography and geodesy the Earth is often approximated by an oblate spheroid, known as the reference ellipsoid, instead of a sph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minoan Seals
Minoan seals are impression seals in the form of carved gemstones and similar pieces in metal, ivory and other materials produced in the Minoan civilization. They are an important part of Minoan art, and have been found in quantity at specific sites, for example in Knossos, Mallia and Phaistos. They were evidently used as a means of identifying documents and objects. Minoan seals are of a small size, 'pocket-size', in the manner of a personal amulet. Many of the images are a similar size to a human fingernail, with a high proportion that of the nail of a little finger. They might be thought of as equivalent to the pocket-sized, scaraboid seals of Ancient Egypt, which were sometimes imitated in Crete. However Minoan seals can be larger, with largest examples of many inches. Minoan seals are the most common surviving type of Minoan art after pottery, with several thousand known, from EM II onwards, in addition to over a thousand impressions, few of which match surviving seals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jewellery
Jewellery ( UK) or jewelry (U.S.) consists of decorative items worn for personal adornment, such as brooches, rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the clothes. From a western perspective, the term is restricted to durable ornaments, excluding flowers for example. For many centuries metal such as gold often combined with gemstones, has been the normal material for jewellery, but other materials such as glass, shells and other plant materials may be used. Jewellery is one of the oldest types of archaeological artefact – with 100,000-year-old beads made from ''Nassarius'' shells thought to be the oldest known jewellery.Study reveals 'oldest jewellery' , '' |
Cell (biology)
The cell is the basic structural and functional unit of life forms. Every cell consists of a cytoplasm enclosed within a membrane, and contains many biomolecules such as proteins, DNA and RNA, as well as many small molecules of nutrients and metabolites.Cell Movements and the Shaping of the Vertebrate Body in Chapter 21 of Molecular Biology of the Cell '' fourth edition, edited by Bruce Alberts (2002) published by Garland Science. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos. It is also common to describe small molecules such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbiology
Microbiology () is the scientific study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, protistology, mycology, immunology, and parasitology. Eukaryotic microorganisms possess membrane-bound organelles and include fungi and protists, whereas prokaryotic organisms—all of which are microorganisms—are conventionally classified as lacking membrane-bound organelles and include Bacteria and Archaea. Microbiologists traditionally relied on culture, staining, and microscopy. However, less than 1% of the microorganisms present in common environments can be cultured in isolation using current means. Microbiologists often rely on molecular biology tools such as DNA sequence based identification, for example the 16S rRNA gene sequence used for bacteria identification. Viruses have been variably classified as organisms, as they have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gemstone
A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, and obsidian) and occasionally organic materials that are not minerals (such as amber, jet, and pearl) are also used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity and notoriety are other characteristics that lend value to gemstones. Apart from jewelry, from earliest antiquity engraved gems and hardstone carvings, such as cups, were major luxury art forms. A gem expert is a gemologist, a gem maker is called a lapidarist or gemcutter; a diamond cutter is called a diamantaire. Characteristics and classification The traditional classification in the West, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minoan Civilization
The Minoan civilization was a Bronze Age Aegean civilization on the island of Crete and other Aegean Islands, whose earliest beginnings were from 3500BC, with the complex urban civilization beginning around 2000BC, and then declining from 1450BC until it ended around 1100BC, during the early Greek Dark Ages, part of a wider bronze age collapse around the Mediterranean. It represents the first advanced civilization in Europe, leaving behind a number of massive building complexes, Minoan art, sophisticated art, and writing systems. Its economy benefited from a network of trade around much of the Mediterranean. The civilization was rediscovered at the beginning of the 20th century through the work of British archaeologist Sir Arthur Evans. The name "Minoan" derives from the mythical Minos, King Minos and was coined by Evans, who identified the site at Knossos with the labyrinth of the Minotaur. The Minoan civilization has been described as the earliest of its kind in Europe, and his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crete
Crete ( el, Κρήτη, translit=, Modern: , Ancient: ) is the largest and most populous of the Greek islands, the 88th largest island in the world and the fifth largest island in the Mediterranean Sea, after Sicily, Sardinia, Cyprus, and Corsica. Crete rests about south of the Greek mainland, and about southwest of Anatolia. Crete has an area of and a coastline of 1,046 km (650 mi). It bounds the southern border of the Aegean Sea, with the Sea of Crete (or North Cretan Sea) to the north and the Libyan Sea (or South Cretan Sea) to the south. Crete and a number of islands and islets that surround it constitute the Region of Crete ( el, Περιφέρεια Κρήτης, links=no), which is the southernmost of the 13 top-level administrative units of Greece, and the fifth most populous of Greece's regions. Its capital and largest city is Heraklion, on the north shore of the island. , the region had a population of 636,504. The Dodecanese are located to the no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three-dimensional Space
Three-dimensional space (also: 3D space, 3-space or, rarely, tri-dimensional space) is a geometric setting in which three values (called ''parameters'') are required to determine the position (geometry), position of an element (i.e., Point (mathematics), point). This is the informal meaning of the term dimension. In mathematics, a tuple of Real number, numbers can be understood as the Cartesian coordinates of a location in a -dimensional Euclidean space. The set of these -tuples is commonly denoted \R^n, and can be identified to the -dimensional Euclidean space. When , this space is called three-dimensional Euclidean space (or simply Euclidean space when the context is clear). It serves as a model of the physical universe (when relativity theory is not considered), in which all known matter exists. While this space remains the most compelling and useful way to model the world as it is experienced, it is only one example of a large variety of spaces in three dimensions called ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knossos
Knossos (also Cnossos, both pronounced ; grc, Κνωσός, Knōsós, ; Linear B: ''Ko-no-so'') is the largest Bronze Age archaeological site on Crete and has been called Europe's oldest city. Settled as early as the Neolithic period, the name Knossos survives from ancient Greek references to the major city of Crete. The palace of Knossos eventually became the ceremonial and political centre of the Minoan civilization and culture. The palace was abandoned at some unknown time at the end of the Late Bronze Age, c. 1380–1100 BC; the reason is unknown, but one of the many disasters that befell the palace is generally put forward. In the First Palace Period (around 2000 BC), the urban area reached a size of as many as 18,000 people. Spelling The name Knossos was formerly latinization of names, Latinized as Cnossus or Cnossos and occasionally Knossus, Gnossus, or Gnossos but is now almost always written Knossos. Neolithic period The site of Knossos has had a very long history ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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