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Stagnant (water)
Water stagnation occurs when water stops flowing. Stagnant water can be a major environmental hazard. Dangers Malaria and dengue are among the main dangers of stagnant water, which can become a breeding ground for the mosquitoes that transmit these diseases. Stagnant water can be dangerous for drinking because it provides a better incubator than running water for many kinds of bacteria and parasites. Stagnant water can be contaminated with human and animal feces, particularly in deserts or other areas of low rainfall. Water stagnation for as little as six days can completely change bacterial community composition and increase cell count. Stagnant water may be classified into the following basic, although overlapping, types: * Water body stagnation (stagnation in swamp, lake, lagoon, river, etc.) * Surface and ground waters stagnation * Trapped water stagnation. The water may be trapped in human artifacts (discarded cans, plant pots, tires, dug-outs, roofs, etc.), as well as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mosquito Larvae
Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning "gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "little fly". Mosquitoes have a slender segmented body, one pair of wings, one pair of halteres, three pairs of long hair-like legs, and elongated mouthparts. The mosquito life cycle consists of egg, larva, pupa, and adult stages. Eggs are laid on the water surface; they hatch into motile larvae that feed on aquatic algae and organic material. These larvae are important food sources for many freshwater animals, such as dragonfly nymphs, many fish, and some birds such as ducks. The adult females of most species have tube-like mouthparts (called a proboscis) that can pierce the skin of a host and feed on blood, which contains protein and iron needed to produce eggs. Thousands of mosquito species feed on the blood of various hosts — ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lotus (genus)
''Lotus'', a latinization of Greek '' lōtos'' (), is a genus of flowering plants that includes most bird's-foot trefoils (also known as bacon-and-eggs) and deervetches and contains many dozens of species distributed worldwide. Depending on the taxonomic authority, roughly between 70 and 150 are accepted. ''Lotus'' is a genus of legumes and its members are adapted to a wide range of habitats, from coastal environments to high altitudes. The genus ''Lotus'' is currently undergoing extensive taxonomic revision. Species native to the Americas have been moved into other genera, such as ''Acmispon'' and '' Hosackia'', as in the second edition of ''The Jepson Manual''. The aquatic plant commonly known as the Indian or sacred lotus is ''Nelumbo nucifera'', a species not closely related to ''Lotus''. Description Most species have leaves with five leaflets; two of these are at the extreme base of the leaf, with the other three at the tip of a naked midrib. This gives the appearance o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Snakehead
The northern snakehead (''Channa argus'') is a species of snakehead fish native to China, Russia, North Korea, and South Korea, ranging from the Amur River to Hainan. It has been introduced to other regions, where it is considered invasive. In Europe, the first report of the species was from Czechoslovakia in 1956. In the United States, the fish is considered to be a highly invasive species. Appearance The distinguishing features of a northern snakehead include a long dorsal fin with 49–50 rays, an anal fin with 31–32 rays, a small, anteriorly depressed head, the eyes above the middle part of the upper jaw, a large mouth extending well beyond the eye, and villiform teeth in bands, with large canines on the lower jaw and palatines. It is generally reported to reach a length up to , but specimens approaching are known according to Russian ichthyologists. The largest registered by the International Game Fish Association weighed , although this was surpassed by a northern sn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lepisosteidae
Gars are members of the family Lepisosteidae, which are the only surviving members of the Ginglymodi, an ancient holosteian group of ray-finned fish, which first appeared during the Triassic, over 240 million years ago. Gars comprise seven living species of fish in two genera that inhabit fresh, brackish, and occasionally marine waters of eastern North America, Central America and Cuba in the Caribbean, though extinct members of the family were more widespread. Gars have elongated bodies that are heavily armored with ganoid scales, and fronted by similarly elongated jaws filled with long, sharp teeth. Gars are sometimes referred to as "garpike", but are not closely related to pike, which are in the fish family Esocidae. All of the gars are relatively large fish, but the alligator gar (''Atractosteus spatula'') is the largest; the alligator gar often grows to a length over and a weight over , and specimens of up to in length have been reported. Unusually, their vascularised sw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purple Bacteria
Purple bacteria or purple photosynthetic bacteria are Gram-negative proteobacteria that are phototrophic, capable of producing their own food via photosynthesis. They are pigmented with bacteriochlorophyll ''a'' or ''b'', together with various carotenoids, which give them colours ranging between purple, red, brown, and orange. They may be divided into two groups – purple sulfur bacteria ( Chromatiales, in part) and purple non-sulfur bacteria ( Rhodospirillaceae). Purple bacteria are anoxygenic phototrophs widely spread in nature, but especially in aquatic environments, where there are anoxic conditions that favor the synthesis of their pigments. Taxonomy Purple bacteria belong to phylum of ''Pseudomonadota''. This phylum was established by Carl Woese in 1987 calling it "purple bacteria and their relatives" even if this is not appropriate because most of them are not purple or photosynthetic. Purple bacteria are distributed between 3 classes:''Alphaproteobacteria'', ''Betap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leptospira
''Leptospira'' ( grc, leptos, italics=yes, 'fine, thin' and la, spira, links=no, 'coil') is a genus of spirochaete bacteria, including a small number of pathogenic and saprophytic species. ''Leptospira'' was first observed in 1907 in kidney tissue slices of a leptospirosis victim who was described as having died of "yellow fever". Taxonomy ''Leptospira'', together with the genera ''Leptonema'' and ''Turneria'', is a member of the family Leptospiraceae. The genus ''Leptospira'' is divided into 20 species based on DNA hybridization studies. Pathogenic ''Leptospira'' :''Leptospira alstonii'' Smythe et al. 2013 ''Leptospira alstoni''" Haake et al. 1993:''Leptospira interrogans'' (Stimson 1907) Wenyon 1926 emend. Faine and Stallman 1982 ["''Spirochaeta interrogans''" Stimson 1907; "''Spirochaeta nodosa''" Hubener & Reiter 1916; "''Spirochaeta icterohaemorrhagiae''" Inada et al. 1916; "''Spirochaeta icterogenes''" Uhlenhuth & Fromme 1916; "''Leptospira icteroides''" Noguchi 1919 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denitrifying Bacteria
Denitrifying bacteria are a diverse group of bacteria that encompass many different phyla. This group of bacteria, together with denitrifying fungi and archaea, is capable of performing denitrification as part of the nitrogen cycle. Denitrification is performed by a variety of denitrifying bacteria that are widely distributed in soils and sediments and that use oxidized nitrogen compounds in absence of oxygen as a terminal electron acceptor. They metabolise nitrogenous compounds using various enzymes, turning nitrogen oxides back to nitrogen gas (N2) or nitrous oxide (N2O). Diversity of denitrifying bacteria There is a great diversity in biological traits.Zumft, W. G. (1997). ''Cell biology and molecular basis of denitrification.'' Microbiology and Molecular Biology Reviews, 61(4), 533–616 Denitrifying bacteria have been identified in over 50 genera with over 125 different species and are estimated to represent 10-15% of bacteria population in water, soil and sediment.Eldor, A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retting
Retting is a process employing the action of micro-organisms and moisture on plants to dissolve or rot away much of the cellular tissues and pectins surrounding bast-fibre bundles, and so facilitating separation of the fibre from the stem.retting. (2009). In Encyclopædia Britannica. Retrieved June 03, 2009, from Encyclopædia Britannica Online:http://www.britannica.com/EBchecked/topic/500159/retting It is used in the production of linen from flax stalks and coir from coconut husks. Water retting The most widely practiced method of retting, water retting, is performed by submerging bundles of stalks in water. The water, penetrating to the central stalk portion, swells the inner cells, bursting the outermost layer, thus increasing absorption of both moisture and decay-producing bacteria. Retting time must be carefully judged; under-retting makes separation difficult, and over-retting weakens the fibre. In double retting, a gentle process producing excellent fibre, the stalks are r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bast Fiber
Bast fibre (also called phloem fibre or skin fibre) is plant fibre collected from the phloem (the "inner bark", sometimes called "skin") or bast surrounding the stem of certain dicotyledonous plants. It supports the conductive cells of the phloem and provides strength to the stem. Some of the economically important bast fibres are obtained from herbs cultivated in agriculture, as for instance flax, hemp, or ramie, but bast fibres from wild plants, as stinging nettle, and trees such as lime or linden, willow, oak, wisteria, and mulberry have also been used in the past. Bast fibres are classified as soft fibres, and are flexible. Fibres from monocotyledonous plants, called "leaf fiber", are classified as hard fibres and are stiff. Since the valuable fibres are located in the phloem, they must often be separated from the xylem material ("woody core"), and sometimes also from the epidermis. The process for this is called retting, and can be performed by micro-organisms either on la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bast Shoe
Bast shoes are shoes made primarily from bast — fiber taken from the bark of trees such as linden. They are a kind of basket, woven and fitted to the shape of a foot. Bast shoes are a traditional footwear of the forest areas of Northern Europe, formerly worn by poorer members of the Finnic peoples, Balts, Russians, Ukrainians and Belarusians. They were easy to manufacture, but not durable. Similar shoes have also been made of strips of birchbark in more northern areas where bast is not readily available. Bast shoes have been worn since prehistoric times. Wooden foot-shaped blocks (lasts) for shaping them have been found in neolithic excavations, e.g. 4900 years old. Bast shoes were still worn in the Russian countryside at the beginning of the twentieth century. Today bast shoes are sold as souvenirs and sometimes worn by ethnographic music or dance troupes as part of their costume. In Russian, they are called lapti (''лапти'', sing. '' лапоть'', lapot); this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bark (botany)
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines, and shrubs. Bark refers to all the tissues outside the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner bark, which in older stems is living tissue, includes the innermost layer of the periderm. The outer bark on older stems includes the dead tissue on the surface of the stems, along with parts of the outermost periderm and all the tissues on the outer side of the periderm. The outer bark on trees which lies external to the living periderm is also called the rhytidome. Products derived from bark include bark shingle siding and wall coverings, spices and other flavorings, tanbark for tannin, resin, latex, medicines, poisons, various hallucinogenic chemicals and cork. Bark has been used to make cloth, canoes, and ropes and used as a surface for paintings and map making. A number of plants a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tilia
''Tilia'' is a genus of about 30 species of trees or bushes, native throughout most of the temperateness, temperate Northern Hemisphere. The tree is known as linden for the European species, and basswood for North American species. In Britain and Ireland they are commonly called lime trees, although they are not related to the citrus Lime (fruit), lime. The genus occurs in Europe and eastern North America, but the greatest species diversity is found in Asia. Under the Cronquist system, Cronquist classification system, this genus was placed in the family Tiliaceae, but genetic research summarised by the Angiosperm Phylogeny Group has resulted in the incorporation of this genus, and of most of the previous family, into the Malvaceae. ''Tilia'' species are mostly large, deciduous trees, reaching typically tall, with oblique-cordate (heart-shaped) leaves across. As with elms, the exact number of species is uncertain, as many of the species can Hybrid (biology), hybridise readily, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
