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In contrast to primary plastids derived from primary endosymbiosis of a prokaryoctyic cyanobacteria, complex plastids originated by secondary endosymbiosis in which a eukaryotic organism engulfed another eukaryotic organism that contained a primary plastid. When a eukaryote engulfs a red or a green alga and retains the algal plastid, that plastid is typically surrounded by more than two membranes. In some cases these plastids may be reduced in their metabolic and/or photosynthetic capacity. Algae with complex plastids derived by secondary endosymbiosis of a red alga include the heterokonts, haptophytes, cryptomonads, and most dinoflagellates (= rhodoplasts). Those that endosymbiosed a green alga include the euglenids and chlorarachniophytes (= chloroplasts). The Apicomplexa, a phylum of obligate parasitic alveolates including the causative agents of malaria (Plasmodium spp.), toxoplasmosis (Toxoplasma gondii), and many other human or animal diseases also harbor a complex plastid (although this organelle has been lost in some apicomplexans, such as Cryptosporidium parvum, which causes cryptosporidiosis). The 'apicoplast' is no longer capable of photosynthesis, but is an essential organelle, and a promising target for antiparasitic drug development.
Some dinoflagellates and sea slugs, in particular of the genus Elysia, take up algae as food and keep the plastid of the digested alga to profit from the photosynthesis; after a while, the plastids are also digested. This process is known as kleptoplasty, from the Greek, kleptes (), thief.
Plastid development cycle
In 1977 J.M Whatley proposed a plastid development cycle which said that plastid development is not always unidirectional but is instead a complicated cyclic process. Proplastids are the precursor of the more differentiated forms of plastids, as shown in the diagram to the right. | Plastid | Wikipedia | 498 | 153522 | https://en.wikipedia.org/wiki/Plastid | Biology and health sciences | Plant cells | null |
Cytokines () are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Due to their size, cytokines cannot cross the lipid bilayer of cells to enter the cytoplasm and therefore typically exert their functions by interacting with specific cytokine receptors on the target cell surface. Cytokines have been shown to be involved in autocrine, paracrine and endocrine signaling as immunomodulating agents.
Cytokines include chemokines, interferons, interleukins, lymphokines, and tumour necrosis factors, but generally not hormones or growth factors (despite some overlap in the terminology). Cytokines are produced by a broad range of cells, including immune cells like macrophages, B lymphocytes, T lymphocytes and mast cells, as well as endothelial cells, fibroblasts, and various stromal cells; a given cytokine may be produced by more than one type of cell. They act through cell surface receptors and are especially important in the immune system; cytokines modulate the balance between humoral and cell-based immune responses, and they regulate the maturation, growth, and responsiveness of particular cell populations. Some cytokines enhance or inhibit the action of other cytokines in complex ways. They are different from hormones, which are also important cell signaling molecules. Hormones circulate in higher concentrations, and tend to be made by specific kinds of cells. Cytokines are important in health and disease, specifically in host immune responses to infection, inflammation, trauma, sepsis, cancer, and reproduction.
The word comes from the ancient Greek language: cyto, from Greek κύτος, kytos, 'cavity, cell' + kines, from Greek κίνησις, kinēsis, 'movement'.
Discovery
Interferon-alpha, an interferon type I, was identified in 1957 as a protein that interfered with viral replication. The activity of interferon-gamma (the sole member of the interferon type II class) was described in 1965; this was the first identified lymphocyte-derived mediator. Macrophage migration inhibitory factor (MIF) was identified simultaneously in 1966 by John David and Barry Bloom. | Cytokine | Wikipedia | 489 | 153663 | https://en.wikipedia.org/wiki/Cytokine | Biology and health sciences | Cell processes | Biology |
In 1969, Dudley Dumonde proposed the term "lymphokine" to describe proteins secreted from lymphocytes and later, proteins derived from macrophages and monocytes in culture were called "monokines". In 1974, pathologist Stanley Cohen, M.D. (not to be confused with the Nobel laureate named Stanley Cohen, who was a PhD biochemist; nor with the MD geneticist Stanley Norman Cohen) published an article describing the production of MIF in virus-infected allantoic membrane and kidney cells, showing its production is not limited to immune cells. This led to his proposal of the term cytokine. In 1993, Ogawa described the early acting growth factors, intermediate acting growth factors and late acting growth factors.
Difference from hormones
Classic hormones circulate in aqueous solution in nanomolar (10 M) concentrations that usually vary by less than one order of magnitude. In contrast, some cytokines (such as IL-6) circulate in picomolar (10 M) concentrations that can increase up to 1,000 times during trauma or infection. The widespread distribution of cellular sources for cytokines may be a feature that differentiates them from hormones. Virtually all nucleated cells, but especially endo/epithelial cells and resident macrophages (many near the interface with the external environment) are potent producers of IL-1, IL-6, and TNF-α. In contrast, classic hormones, such as insulin, are secreted from discrete glands such as the pancreas. The current terminology refers to cytokines as immunomodulating agents.
A contributing factor to the difficulty of distinguishing cytokines from hormones is that some immunomodulating effects of cytokines are systemic (i.e., affecting the whole organism) rather than local. For instance, to accurately utilize hormone terminology, cytokines may be autocrine or paracrine in nature, and chemotaxis, chemokinesis and endocrine as a pyrogen. Essentially, cytokines are not limited to their immunomodulatory status as molecules. | Cytokine | Wikipedia | 445 | 153663 | https://en.wikipedia.org/wiki/Cytokine | Biology and health sciences | Cell processes | Biology |
Nomenclature
Cytokines have been classed as lymphokines, interleukins, and chemokines, based on their presumed cell of secretion, function, or target of action. Because cytokines are characterised by considerable redundancy and pleiotropism, such distinctions, allowing for exceptions, are obsolete.
The term interleukin was initially used by researchers for those cytokines whose presumed targets are principally white blood cells (leukocytes). It is now used largely for designation of newer cytokine molecules and bears little relation to their presumed function. The vast majority of these are produced by T-helper cells.
Lymphokines: produced by lymphocytes
Monokines: produced exclusively by monocytes
Interferons: involved in antiviral responses
Colony stimulating factors: support the growth of cells in semisolid media
Chemokines: mediate chemoattraction (chemotaxis) between cells.
Classification
Structural
Structural homogeneity has been able to partially distinguish between cytokines that do not demonstrate a considerable degree of redundancy so that they can be classified into four types:
The four-α-helix bundle family (): member cytokines have three-dimensional structures with a bundle of four α-helices. This family, in turn, is divided into three sub-families:
the IL-2 subfamily. This is the largest family. It contains several non-immunological cytokines including erythropoietin (EPO) and thrombopoietin (TPO). They can be grouped into long-chain and short-chain cytokines by topology. Some members share the common gamma chain as part of their receptor.
the interferon (IFN) subfamily.
the IL-10 subfamily.
The IL-1 family, which primarily includes IL-1 and IL-18.
The cysteine knot cytokines () include members of the transforming growth factor beta superfamily, including TGF-β1, TGF-β2 and TGF-β3.
The IL-17 family, which has yet to be completely characterized, though member cytokines have a specific effect in promoting proliferation of T-cells that have cytotoxic effects. | Cytokine | Wikipedia | 471 | 153663 | https://en.wikipedia.org/wiki/Cytokine | Biology and health sciences | Cell processes | Biology |
Functional
A classification that proves more useful in clinical and experimental practice outside of structural biology divides immunological cytokines into those that enhance cellular immune responses, type 1 (TNFα, IFN-γ, etc.), and those that enhance antibody responses, type 2 (TGF-β, IL-4, IL-10, IL-13, etc.). A key focus of interest has been that cytokines in one of these two sub-sets tend to inhibit the effects of those in the other. Dysregulation of this tendency is under intensive study for its possible role in the pathogenesis of autoimmune disorders. Several inflammatory cytokines are induced by oxidative stress. The fact that cytokines themselves trigger the release of other cytokines and also lead to increased oxidative stress makes them important in chronic inflammation, as well as other immunoresponses, such as fever and acute phase proteins of the liver (IL-1,6,12, IFN-a). Cytokines also play a role in anti-inflammatory pathways and are a possible therapeutic treatment for pathological pain from inflammation or peripheral nerve injury. There are both pro-inflammatory and anti-inflammatory cytokines that regulate this pathway.
Receptors
In recent years, the cytokine receptors have come to demand the attention of more investigators than cytokines themselves, partly because of their remarkable characteristics and partly because a deficiency of cytokine receptors has now been directly linked to certain debilitating immunodeficiency states. In this regard, and also because the redundancy and pleomorphism of cytokines are, in fact, a consequence of their homologous receptors, many authorities think that a classification of cytokine receptors would be more clinically and experimentally useful.
A classification of cytokine receptors based on their three-dimensional structure has, therefore, been attempted. Such a classification, though seemingly cumbersome, provides several unique perspectives for attractive pharmacotherapeutic targets. | Cytokine | Wikipedia | 419 | 153663 | https://en.wikipedia.org/wiki/Cytokine | Biology and health sciences | Cell processes | Biology |
Immunoglobulin (Ig) superfamily, which are ubiquitously present throughout several cells and tissues of the vertebrate body, and share structural homology with immunoglobulins (antibodies), cell adhesion molecules, and even some cytokines. Examples: IL-1 receptor types.
Hemopoietic Growth Factor (type 1) family, whose members have certain conserved motifs in their extracellular amino-acid domain. The IL-2 receptor belongs to this chain, whose γ-chain (common to several other cytokines) deficiency is directly responsible for the x-linked form of Severe Combined Immunodeficiency (X-SCID).
Interferon (type 2) family, whose members are receptors for IFN β and γ.
Tumor necrosis factors (TNF) (type 3) family, whose members share a cysteine-rich common extracellular binding domain, and includes several other non-cytokine ligands like CD40, CD27 and CD30, besides the ligands on which the family is named.
Seven transmembrane helix family, the ubiquitous receptor type of the animal kingdom. All G protein-coupled receptors (for hormones and neurotransmitters) belong to this family. Chemokine receptors, two of which act as binding proteins for HIV (CD4 and CCR5), also belong to this family.
Interleukin-17 receptor (IL-17R) family, which shows little homology with any other cytokine receptor family. Structural motifs conserved between members of this family include: an extracellular fibronectin III-like domain, a transmembrane domain and a cytoplasmic SERIF domain. The known members of this family are as follows: IL-17RA, IL-17RB, IL-17RC, IL17RD and IL-17RE. | Cytokine | Wikipedia | 391 | 153663 | https://en.wikipedia.org/wiki/Cytokine | Biology and health sciences | Cell processes | Biology |
Cellular effects
Each cytokine has a matching cell-surface receptor. Subsequent cascades of intracellular signaling then alter cell functions. This may include the upregulation and/or downregulation of several genes and their transcription factors, resulting in the production of other cytokines, an increase in the number of surface receptors for other molecules, or the suppression of their own effect by feedback inhibition. The effect of a particular cytokine on a given cell depends on the cytokine, its extracellular abundance, the presence and abundance of the complementary receptor on the cell surface, and downstream signals activated by receptor binding; these last two factors can vary by cell type. Cytokines are characterized by considerable redundancy, in that many cytokines appear to share similar functions. It seems to be a paradox that cytokines binding to antibodies have a stronger immune effect than the cytokine alone. This may lead to lower therapeutic doses.
It has been shown that inflammatory cytokines cause an IL-10-dependent inhibition of T-cell expansion and function by up-regulating PD-1 levels on monocytes, which leads to IL-10 production by monocytes after binding of PD-1 by PD-L. Adverse reactions to cytokines are characterized by local inflammation and/or ulceration at the injection sites. Occasionally such reactions are seen with more widespread papular eruptions.
Roles in health and disease
Cytokines are involved in several developmental processes during embryonic development. Cytokines are released from the blastocyst, and are also expressed in the endometrium, and have critical roles in the stages of zona hatching, and implantation. Cytokines are crucial for fighting off infections and in other immune responses. However, they can become dysregulated and pathological in inflammation, trauma, sepsis, and hemorrhagic stroke. Dysregulated cytokine secretion in the aged population can lead to inflammaging, and render these individuals more vulnerable to age-related diseases like neurodegenerative diseases and type 2 diabetes.
A 2019 review was inconclusive as to whether cytokines play any definitive role in ME/CFS.
A 2024 study found a positive correlation between plasma interleukin IL-2 and fatigue in patients with type 1 narcolepsy.
Adverse effects | Cytokine | Wikipedia | 487 | 153663 | https://en.wikipedia.org/wiki/Cytokine | Biology and health sciences | Cell processes | Biology |
Adverse effects of cytokines have been linked to many disease states and conditions ranging from schizophrenia, major depression and Alzheimer's disease to cancer. T regulatory cells (Tregs) and related-cytokines are effectively engaged in the process of tumor immune escape and functionally inhibit immune response against the tumor. Forkhead box protein 3 (Foxp3) as a transcription factor is an essential molecular marker of Treg cells. Foxp3 polymorphism (rs3761548) might be involved in cancer progression like gastric cancer through influencing Tregs function and the secretion of immunomodulatory cytokines such as IL-10, IL-35, and TGF-β.
Normal tissue integrity is preserved by feedback interactions between diverse cell types mediated by adhesion molecules and secreted cytokines; disruption of normal feedback mechanisms in cancer threatens tissue integrity.
Over-secretion of cytokines can trigger a dangerous cytokine storm syndrome. Cytokine storms may have been the cause of severe adverse events during a clinical trial of TGN1412. Cytokine storms are also suspected to have been the main cause of death in the 1918 "Spanish Flu" pandemic. Deaths were weighted more heavily towards people with healthy immune systems, because of their ability to produce stronger immune responses, with dramatic increases in cytokine levels. Another example of cytokine storm is seen in acute pancreatitis. Cytokines are integral and implicated in all angles of the cascade, resulting in the systemic inflammatory response syndrome and multi-organ failure associated with this intra-abdominal catastrophe. In the COVID-19 pandemic, some deaths from COVID-19 have been attributable to cytokine release storms. Current data suggest cytokine storms may be the source of extensive lung tissue damage and dysfunctional coagulation in COVID-19 infections.
Medical use as drugs | Cytokine | Wikipedia | 389 | 153663 | https://en.wikipedia.org/wiki/Cytokine | Biology and health sciences | Cell processes | Biology |
Some cytokines have been developed into protein therapeutics using recombinant DNA technology. Recombinant cytokines being used as drugs as of 2014 include:
Bone morphogenetic protein (BMP), used to treat bone-related conditions
Erythropoietin (EPO), used to treat anemia
Granulocyte colony-stimulating factor (G-CSF), used to treat neutropenia in cancer patients
Granulocyte macrophage colony-stimulating factor (GM-CSF), used to treat neutropenia and fungal infections in cancer patients
Interferon alfa, used to treat hepatitis C and multiple sclerosis
Interferon beta, used to treat multiple sclerosis
Interleukin 2 (IL-2), used to treat cancer.
Interleukin 11 (IL-11), used to treat thrombocytopenia in cancer patients.
Interferon gamma is used to treat chronic granulomatous disease and osteopetrosis | Cytokine | Wikipedia | 213 | 153663 | https://en.wikipedia.org/wiki/Cytokine | Biology and health sciences | Cell processes | Biology |
The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth. By extension, it is also a plane of reference in the equatorial coordinate system. In other words, the celestial equator is an abstract projection of the terrestrial equator into outer space. Due to Earth's axial tilt, the celestial equator is currently inclined by about 23.44° with respect to the ecliptic (the plane of Earth's orbit), but has varied from about 22.0° to 24.5° over the past 5 million years due to perturbation from other planets.
An observer standing on Earth's equator visualizes the celestial equator as a semicircle passing through the zenith, the point directly overhead. As the observer moves north (or south), the celestial equator tilts towards the opposite horizon. The celestial equator is defined to be infinitely distant (since it is on the celestial sphere); thus, the ends of the semicircle always intersect the horizon due east and due west, regardless of the observer's position on Earth. At the poles, the celestial equator coincides with the astronomical horizon. At all latitudes, the celestial equator is a uniform arc or circle because the observer is only finitely far from the plane of the celestial equator, but infinitely far from the celestial equator itself.
Astronomical objects near the celestial equator appear above the horizon from most places on earth, but they culminate (reach the meridian) highest near the equator. The celestial equator currently passes through these constellations:
These are the most globally visible constellations.
Over thousands of years, the orientation of Earth's equator and thus the constellations the celestial equator passes through will change due to axial precession.
Celestial bodies other than Earth also have similarly defined celestial equators. | Celestial equator | Wikipedia | 366 | 153681 | https://en.wikipedia.org/wiki/Celestial%20equator | Physical sciences | Celestial sphere: General | Astronomy |
The Humber Bridge is a single-span road suspension bridge near Kingston upon Hull, East Riding of Yorkshire, England. When it opened to traffic on 24 June 1981, it was the longest of its type in the world; the Akashi Kaikyō Bridge surpassed it in 1998, and it became the thirteenth-longest by 2024.
The bridge spans the Humber (an estuary formed by the rivers Trent and Ouse), between Barton-upon-Humber on the south bank and Hessle on the north bank, connecting the East Riding of Yorkshire with North Lincolnshire. Both sides of the bridge were in the non-metropolitan county of Humberside until its dissolution in 1996. The bridge can be seen for miles around, from as far as Patrington in the East Riding of Yorkshire, and from out to sea miles off the coast. It is a Grade I listed building.
By 2006, the bridge carried an average of 120,000 vehicles per week. The toll was £3.00 each way for cars (higher for commercial vehicles), which made it the most expensive toll crossing in the United Kingdom. In April 2012, the toll was halved to £1.50 each way after the UK government deferred £150 million from the bridge's outstanding debt.
History
Before the bridge, commuters crossed the Humber on the Humber Ferry from Corporation Pier at Hull and New Holland Pier at New Holland, Lincolnshire, or by road via the M62 (from 1976), M18 (from 1979) and M180 motorways, crossing, by way of the Ouse Bridge, the River Ouse near Goole (connected to the Humber). Until the mid-1970s the route south was via the single-carriageway A63 and the A614 (via grid-locked Thorne) where it met the busy A18 and crossed the Stainforth and Keadby Canal at Keadby Bridge, a swing bridge, which formed a bottleneck on the route, and on through Finningley and Bawtry, meeting the east–west A631. | Humber Bridge | Wikipedia | 424 | 153761 | https://en.wikipedia.org/wiki/Humber%20Bridge | Technology | Bridges | null |
The journey was along straight single-carriageway roads across foggy moors interrupted by bottlenecks for most of the journey to Blyth, Nottinghamshire, where it met the A1, and the accident rate was high. Debates in Parliament were held on the low standard of the route across the windswept plains around Goole. It was not unexpected that under these conditions, a Humber Bridge, with connecting dual-carriageway approach roads and grade-separated junctions, would seem worthwhile. By the time the bridge opened, much of this inferior route had been transformed by dualling of the A63 and its bypasses, extending the M62 and the connecting of the M18 from Thorne to Wadworth. The obvious need for a Humber Bridge had been reduced by the late 1970s with the improvements of the motorway infrastructure in the region. Although welcome, these improvements detracted from the need for vehicles to cross a bridge from Hessle to Barton. The Humber Bridge was a victim of the success of the M62 before it opened. A hovercraft service, Minerva and Mercury, linked Hull Pier and Grimsby Docks from February to October 1969 but suffered relatively frequent breakdowns.
Act of Parliament
Plans for a bridge were drawn up in the 1930s when a team of engineers compiled a report on whether to bridge or tunnel the estuary. It was decided that a bridge would cost £1,750,000 over a tunnel which was costed at £7,200,000. Revised plans were unveiled in 1955, but work did not begin until 27 July 1972. The (7 & 8 Eliz. 2. c. xlvi), was promoted by Kingston Upon Hull Corporation and established the Humber Bridge Board to manage and raise funds to build the bridge and buy the land required for the approach roads.
1966 Kingston upon Hull North by-election
The allocation of funds proved impossible until the 1966 Kingston upon Hull North by-election. Labour Prime Minister Harold Wilson prevailed upon his Minister of Transport Barbara Castle to sanction the building of the bridge. Dismay at the long wait for a crossing led to Christopher Rowe writing a protest song, "The Humber Bridge".
Design | Humber Bridge | Wikipedia | 439 | 153761 | https://en.wikipedia.org/wiki/Humber%20Bridge | Technology | Bridges | null |
The consulting engineers for the project were Freeman Fox & Partners (now Arcadis NV). Sir Ralph Freeman had produced the first ideas in 1927 and in the early 1930s the cost of the project was estimated at £1.725 million and that the bridge would be unlikely to recoup the construction or maintenance costs. In 1935 he had an idea for a suspension bridge for the Humber Tunnel Executive Committee. Sir Gilbert Roberts produced more ideas in 1955 for a bridge with a central span, costing £15 million, to be paid for by East Riding County Council and Lindsey County Council. When it became likely that a bridge would be constructed, Imperial College-educated Bernard Wex OBE (1922–1990) produced the design in 1964 that was actually built. The bridge was built to last 120 years. In 1985 Wex was awarded the Telford Medal by the Institution of Civil Engineers. In the 1950s he had helped to design High Marnham Power Station. He was a former UK chairman of the International Association of Bridge and Structural Engineers and helped to found the Steel Construction Institute in 1976.
The architect was R. E. Slater ARIBA. The administration building (for the tolls) was designed by Parker & Rosner. The landscaping was designed by Prof Arnold Weddle. Wind tunnel testing took place at the National Maritime Institute (now part of BMT Limited) at Teddington, and the road deck was designed for wind speeds up to , but storms featuring considerably lower wind speeds have been cited as grounds for emergency repairs in recent years.
Construction
The main contractor for the steel superstructure was British Bridge Builders (the same grouping as for the Forth and Severn Road Bridges comprising Sir William Arrol & Co., then a unit of NEI Cranes Ltd, Cleveland Bridge & Engineering Company, and Redpath Dorman Long Ltd). The contractor for the concrete towers, anchorages and sub-structure was John Howard & Co Ltd of Chatham, Kent, which was later bought by Amec. Concrete was chosen for the towers, instead of steel, partly due to cost, but also to suit the landscape. | Humber Bridge | Wikipedia | 421 | 153761 | https://en.wikipedia.org/wiki/Humber%20Bridge | Technology | Bridges | null |
Work began on the southern approach road in July 1972 by Clugston Construction of Scunthorpe. The approach road to the A1077 junction, by Costain Civil Engineering, began in September 1976. It included a span from the southern anchorage of seven pre-stressed concrete box sections and the A1077 junction, costing £4.25 million. Work on the bridge substructure (foundations) began in March 1973. To reduce heat of hydration in the concrete, which produces calcium silicate hydrate from belite, as much as 60 per cent of the Portland cement was replaced with ground granulated blast-furnace slag (GGBS). It took longer to build the southern anchorage due to a diaphragm wall design due to there not being enough shallow bedrock. The main southern approach roads from Barton to the M180 motorway junction at Barnetby were built in the late 1970s by Clugston Construction of Scunthorpe, opening in 1978.
The towers were constructed by slipforming and the north tower was completed by May 1974. The southern foundations were completed in September 1975, with the pier completed in March 1976, and the southern tower was completed by September 1976; the bridge had been planned to open in 1976. The northern tower and anchorage was built on solid chalk but the southern tower and anchorage were built on fissured Kimmeridge Clay, from the southern shore and built with a difficult caisson design. The subcontractor for the concrete was Tileman & Co. of Shipston-on-Stour, south Warwickshire.
Cable spinning took place between September 1977 and July 1979. Each cable weighs , with 37 strands of 404 lengths of cable. The cable on the northern span has four extra strands. Each cable can take a load of . The deck is of box girder form, the box sections around each. The first box sections were assembled in June 1975 and put into the main span on 9 November 1979. The toll buildings and north approach road were built by A. F. Budge of Retford, Nottinghamshire, costing £2.9 million. Work began on the administration building in November 1976. The toll system was manufactured by Plessey Controls of Poole, Dorset. Corrosion resistance on the steelwork was provided by Camrex Corrosion of Bellshill, North Lanarkshire. The road was laid by Tarmac Roadstone of Wolverhampton with mastic asphalt. In 2017, the bridge was designated a Grade I listed building. | Humber Bridge | Wikipedia | 502 | 153761 | https://en.wikipedia.org/wiki/Humber%20Bridge | Technology | Bridges | null |
A-frames
At road level the deck was fastened to the towers through four rocking A-frames, to allow for movement caused by the catenary supporting the deck from above deflecting with the weight of passing traffic, from thermal expansion, and from changes in wind loading. The devices catered for a maximum deflection of 2 metres. By 2011 it was noticed that the pivot-pin bearings carrying the frames had worn, allowing them to drop towards the support structure. Each frame was replaced by two new components: a vertical linkage to cater for longitudinal movement and a sliding bearing for lateral displacement.
Opening
The bridge opened to traffic on 24 June 1981 at a final cost of £91 million (). It was opened officially by Queen Elizabeth II on 17 July 1981, in a ceremony that included a prayer of dedication by the Archbishop of York and a fly-past by the Red Arrows.
World record
With a centre span of and a total length of , the Humber Bridge was the longest single-span suspension bridge in the world for 17 years, until the Akashi Kaikyō Bridge opened in Japan on 5 April 1998.
Local benefits
The road-distance between Hull and Grimsby fell by nearly ; the town of Scunthorpe and environs were relieved of the passing traffic between Hull and Grimsby.
Bridge statistics
The bridge's surface takes the form of a dual carriageway with a lower-level foot and cycle path on both sides. There is a permanent speed limit on the full length of the bridge.
Each tower consists of a pair of hollow vertical concrete columns, each tall and tapering from square at the base to at the top. The bridge is designed to tolerate constant motion and bends more than in winds of . The towers, although vertical, are farther apart at the top than the bottom due to the curvature of the Earth.
The total length of the suspension cable is . The north tower is on the bank and has foundations down to . The south tower is in the water, and descends to as a consequence of the shifting sandbanks that make up the estuary. | Humber Bridge | Wikipedia | 420 | 153761 | https://en.wikipedia.org/wiki/Humber%20Bridge | Technology | Bridges | null |
The bridge held the record for the world's longest single-span suspension bridge for 17 years, from its opening in July 1981 until the opening of the Akashi Kaikyō Bridge in April 1998. In June 2024, it became the thirteenth-longest, single-span suspension bridge. The central span, at , is the longest in Britain and in the Western Hemisphere. It remains the longest single-span suspension bridge in the world that can be crossed on foot or by bicycle.
The bridge is crossed twice during the annual Humber Bridge Half Marathon in June, and Hull Marathon in September.
Toll update project
In July 2013, work began on introducing a new electronic tolling system. The existing Humber Bridge toll system was largely the same as it was when the bridge opened in 1981. The computer system was over 15 years old, absorbed an increasing amount of maintenance, and needed to be replaced. The project would decrease waiting times and was welcomed by business and transport leaders.
In the first phase, the toll booths and the toll plaza canopy were replaced, and in the second phase, writing, testing and setting up the new toll system was completed. From 2015 bridge users could set up an account with the bridge and pay into it. Account holders receive a device called the HumberTAG, a small electronic tag that enables the system to recognise the bridge user; the toll is automatically deducted from the user's account. Two central lanes through the plaza are free-flowing; they do not have booths and account holders are able to cross the bridge without stopping.
Incidents and suicides
During construction of the bridge, the road deck sections were floated up on barges then hoisted into place by cables. During one of these lifting operations some of the cables on two of the road deck sections failed, leaving the sections hanging at an angle. The sections were subsequently installed.
On more than 200 occasions, people have jumped or fallen from the bridge since it was opened in 1981; only five people have survived. Between 1990 and February 2001 the Humber Rescue Team launched its boat 64 times to deal with people falling or jumping off the bridge. Notable incidents include the cases of a West Yorkshire woman and her two-year-old daughter who fell off the bridge in 2005 and that of a man jumping from the bridge to his death on the A63 road below in September 2006.
Plans were announced on 26 December 2009 to construct a suicide barrier along the walkways of the bridge; design constraints were cited as the reason for not installing barriers during the construction of the bridge. | Humber Bridge | Wikipedia | 512 | 153761 | https://en.wikipedia.org/wiki/Humber%20Bridge | Technology | Bridges | null |
In May 2017, a YouTuber with the username 'Night Scape', along with a small group, illegally scaled the bridge without safety equipment. The group of young men climbed up the structure to the top of the bridge using the suspension wires as handholds. Humberside Police and the Humber Bridge Board are reviewing the security measures.
On 3 April 2021, the Humber Bridge was closed to pedestrians and cyclists following an unspecified 'recent incident'. The decision came after multiple deaths at the bridge in the month of March. Following the death of one individual that month, a petition calling for increased safety measures to 'secure' the bridge had gained thousands of signatures. Concerns were raised over how the change will affect those who commute on foot or by bike. On 6 May 2021, the bridge was reopened to pedestrians and cyclists between the hours of 0500 and 2100; only users registered in advance could use the bridge outside of those hours. More CCTV and notices were erected and more staff assigned to patrol the crossing.
Finances
The bridge had a toll charge of £1.50 for cars from 1 April 2012, until for six months it was £3.00 and the only trunk road British toll bridge to charge motorcycles (£1.20). In 2004 many motorcyclists held a slow-pay protest, taking off gloves and helmets and paying the toll in large denomination bank notes. Police reported that the protest caused a queue long.
In 1996, Parliament passed the Humber Bridge (Debts) Act 1996 to reorganise the board's liabilities to ensure the bridge could be safely maintained. Much of the interest on the debt was suspended and deferred in a refinancing which saw no write off – the balance was to be paid using tolls. | Humber Bridge | Wikipedia | 361 | 153761 | https://en.wikipedia.org/wiki/Humber%20Bridge | Technology | Bridges | null |
In 2006, Shona McIsaac, Labour MP for Cleethorpes, tabled a Private Member's Bill, the Humber Bridge Bill. The bill would have made amendments to the Humber Bridge Act 1959 (7 & 8 Eliz. 2. c. xlvi) "requiring the Secretary of State to give directions to members of the Humber Bridge Board regarding healthcare and to review the possibility of facilitating journeys across the Humber Bridge in relation to healthcare". The aim was to allow patients travelling between the banks for medical treatment to cross without paying the toll and to allow the Secretary of State for Transport to appoint two members of the board to represent the interests of the NHS. Even though the Bill received cross-party support (it was co-sponsored by Shadow Home Secretary David Davis and supported by all other MPs representing North Lincolnshire and the East Riding of Yorkshire) it ran out of time later that year.
A protest at the bridge on 1 September 2007 was supported by the local Cancer Patients Involvement Group, the Road Haulage Association, Diana Wallis (MEP for Yorkshire and the Humber) and local business and council representatives. The government responded to the petition on 14 January 2008, stating that "Concessions or exemptions from tolls on the Humber Bridge are a matter for the Humber Bridge Board".
In October 2008, a joint campaign was launched by the Scunthorpe Telegraph, Hull Daily Mail and Grimsby Telegraph to abolish the toll. The papers' campaign, A Toll Too Far, was launched after a mooted increase in the toll, receiving much support from councillors and MPs serving Lincolnshire and the East Riding of Yorkshire. The campaign was to stave off a potential increase, secure a reduction to £1.00 and ultimately to be abolished. Thousands of readers backed the campaign with a paper and an online petition.
A public inquiry into the tolls was held in March 2009 by independent inspector Neil Taylor. In July 2009, the Department for Transport announced that it had decided not to allow the proposed increase. Transport Minister Sadiq Khan said he did not believe it was right for the tolls to be raised in the current economic climate. In October 2009, the government approved a £6 million grant for maintenance costs, which meant that there would be no toll increase before 2011 at the earliest, by which time tolls would have been frozen for five years. | Humber Bridge | Wikipedia | 479 | 153761 | https://en.wikipedia.org/wiki/Humber%20Bridge | Technology | Bridges | null |
The board applied again to the Department of Transport in September 2010, to raise the tolls from April 2011 but the government ordered a public inquiry into the application. A three-day public inquiry was held in Hull in early March 2011. Following the recommendation by the planning inspector, the government gave approval, on 14 June 2011, for the increase. The toll was raised on 1 October 2011, at which point it became the most expensive in the United Kingdom. The Severn Bridge/Second Severn Crossing charged £5.70 for Wales-bound traffic.
In the 2011 Autumn Statement on 29 November, the Chancellor of the Exchequer, George Osborne, announced that the government had agreed to reduce the debt on the bridge by £150 million, which would allow the toll for cars to be halved to £1.50. Following the government accepting the agreement, between the four local councils, to meet a portion of the debt if revenues proved insufficient, the Transport Secretary, Justine Greening, confirmed the reduction on 29 February 2012, with effect from April.
Image gallery | Humber Bridge | Wikipedia | 208 | 153761 | https://en.wikipedia.org/wiki/Humber%20Bridge | Technology | Bridges | null |
Crystal optics is the branch of optics that describes the behaviour of light in anisotropic media, that is, media (such as crystals) in which light behaves differently depending on which direction the light is propagating. The index of refraction depends on both composition and crystal structure and can be calculated using the Gladstone–Dale relation. Crystals are often naturally anisotropic, and in some media (such as liquid crystals) it is possible to induce anisotropy by applying an external electric field.
Isotropic media
Typical transparent media such as glasses are isotropic, which means that light behaves the same way no matter which direction it is travelling in the medium. In terms of Maxwell's equations in a dielectric, this gives a relationship between the electric displacement field D and the electric field E:
where ε0 is the permittivity of free space and P is the electric polarization (the vector field corresponding to electric dipole moments present in the medium). Physically, the polarization field can be regarded as the response of the medium to the electric field of the light.
Electric susceptibility
In an isotropic and linear medium, this polarization field P is proportional and parallel to the electric field E:
where χ is the electric susceptibility of the medium. The relation between D and E is thus:
where
is the dielectric constant of the medium. The value 1+χ is called the relative permittivity of the medium, and is related to the refractive index n, for non-magnetic media, by
Anisotropic media
In an anisotropic medium, such as a crystal, the polarisation field P is not necessarily aligned with the electric field of the light E. In a physical picture, this can be thought of as the dipoles induced in the medium by the electric field having certain preferred directions, related to the physical structure of the crystal. This can be written as:
Here χ is not a number as before but a tensor of rank 2, the electric susceptibility tensor. In terms of components in 3 dimensions:
or using the summation convention:
Since χ is a tensor, P is not necessarily colinear with E. | Crystal optics | Wikipedia | 451 | 153783 | https://en.wikipedia.org/wiki/Crystal%20optics | Physical sciences | Crystallography | Physics |
In nonmagnetic and transparent materials, χij = χji, i.e. the χ tensor is real and symmetric. In accordance with the spectral theorem, it is thus possible to diagonalise the tensor by choosing the appropriate set of coordinate axes, zeroing all components of the tensor except χxx, χyy and χzz. This gives the set of relations:
The directions x, y and z are in this case known as the principal axes of the medium. Note that these axes will be orthogonal if all entries in the χ tensor are real, corresponding to a case in which the refractive index is real in all directions.
It follows that D and E are also related by a tensor:
Here ε is known as the relative permittivity tensor or dielectric tensor. Consequently, the refractive index of the medium must also be a tensor. Consider a light wave propagating along the z principal axis polarised such the electric field of the wave is parallel to the x-axis. The wave experiences a susceptibility χxx and a permittivity εxx. The refractive index is thus:
For a wave polarised in the y direction:
Thus these waves will see two different refractive indices and travel at different speeds. This phenomenon is known as birefringence and occurs in some common crystals such as calcite and quartz.
If χxx = χyy ≠ χzz, the crystal is known as uniaxial. (See Optic axis of a crystal.) If χxx ≠ χyy and χyy ≠ χzz the crystal is called biaxial. A uniaxial crystal exhibits two refractive indices, an "ordinary" index (no) for light polarised in the x or y directions, and an "extraordinary" index (ne) for polarisation in the z direction. A uniaxial crystal is "positive" if ne > no and "negative" if ne < no. Light polarised at some angle to the axes will experience a different phase velocity for different polarization components, and cannot be described by a single index of refraction. This is often depicted as an index ellipsoid.
Other effects | Crystal optics | Wikipedia | 448 | 153783 | https://en.wikipedia.org/wiki/Crystal%20optics | Physical sciences | Crystallography | Physics |
Certain nonlinear optical phenomena such as the electro-optic effect cause a variation of a medium's permittivity tensor when an external electric field is applied, proportional (to lowest order) to the strength of the field. This causes a rotation of the principal axes of the medium and alters the behaviour of light travelling through it; the effect can be used to produce light modulators.
In response to a magnetic field, some materials can have a dielectric tensor that is complex-Hermitian; this is called a gyro-magnetic or magneto-optic effect. In this case, the principal axes are complex-valued vectors, corresponding to elliptically polarized light, and time-reversal symmetry can be broken. This can be used to design optical isolators, for example.
A dielectric tensor that is not Hermitian gives rise to complex eigenvalues, which corresponds to a material with gain or absorption at a particular frequency. | Crystal optics | Wikipedia | 194 | 153783 | https://en.wikipedia.org/wiki/Crystal%20optics | Physical sciences | Crystallography | Physics |
The naginata (, ) is a polearm and one of several varieties of traditionally made Japanese blades (nihontō). Naginata were originally used by the samurai class of feudal Japan, as well as by ashigaru (foot soldiers) and sōhei (warrior monks). The naginata is the iconic weapon of the onna-musha, a type of female warrior belonging to the Japanese nobility. A common misconception is that the Naginata is a type of sword, rather than a polearm.
Description
A naginata consists of a wooden or metal pole with a curved single-edged blade on the end; it is similar to the Chinese guan dao or the European glaive. Similar to the katana, naginata often have a round handguard (tsuba) between the blade and shaft, when mounted in a koshirae (furniture). The 30 cm to 60 cm (11.8 inches to 23.6 inches) naginata blade is forged in the same manner as traditional Japanese swords. The blade has a long tang (nakago) which is inserted in the shaft.
The blade is removable and is secured by means of a wooden peg called mekugi (目釘) that passes through a hole (mekugi-ana) in both the tang and the shaft.
The shaft ranges from 120 cm to 240 cm (47.2 inches to 94.5 inches) in length and is oval shaped. The area of the shaft where the tang sits is the tachiuchi or tachiuke. The tachiuchi/tachiuke would be reinforced with metal rings (naginata dogane or semegane), and/or metal sleeves (sakawa) and wrapped with cord (san-dan maki). The end of the shaft has a heavy metal end cap (ishizuki or hirumaki). When not in use the blade would be covered with a wooden sheath.
History
It is assumed that the naginata was developed from an earlier weapon type of the later 1st millennium AD, the hoko yari. Another assumption is that the naginata was developed by lengthening the hilt of the tachi at the end of the Heian period, and it is not certain which theory is correct. | Naginata | Wikipedia | 473 | 153784 | https://en.wikipedia.org/wiki/Naginata | Technology | Polearms | null |
It is generally believed that naginata first appeared in the Heian period (794–1185). The term naginata first appeared in historical documents in the Heian period. The earliest clear references to naginata date from 1146. In Honchō Seiki compiled from 1150 to 1159 in the late Heian period, it is recorded that Minamoto no Tsunemitsu mentioned that his weapon was a naginata.
In the early Heian period, battles were mainly fought using yumi (longbow) on horseback, but in the late Heian period, battles on foot began to increase and naginata also came to be used on the battlefield. The naginata was appreciated because it was a weapon that could maintain an optimum distance from the enemy in close combat. During the Genpei War (1180–1185), in which the Taira clan was pitted against the Minamoto clan, the naginata rose to a position of particularly high esteem, being regarded as an extremely effective weapon by warriors. The Tale of the Heike, which records the Genpei War, there are descriptions such as ō naginata (lit. big naginata) and ko naginata (lit. little naginata), which show that naginata of various lengths were used. The naginata proved excellent at dismounting cavalry and disabling riders. The widespread adoption of the naginata as a battlefield weapon forced the introduction of greaves as a part of Japanese armor. Ōyamazumi Shrine houses two naginata that are said to have been dedicated by Tomoe Gozen and Benkei at the end of the Heian period and they are designated as Important Cultural Property. | Naginata | Wikipedia | 357 | 153784 | https://en.wikipedia.org/wiki/Naginata | Technology | Polearms | null |
However, according to Karl Friday, there were various notations for naginata in the Heian period and the earliest physical evidence for naginata was in the middle of the Kamakura period, so there is a theory that says when they first appeared is unclear. Earlier 10th through 12th century sources refer to "long swords" that while a common medieval term or orthography for naginata, could also simply be referring to conventional swords; one source describes a naginata being drawn with the verb , commonly associated with swords, rather than , the verb otherwise used in medieval texts for unsheathing naginata. Some 11th and 12th century mentions of hoko may actually have been referring to naginata. The commonly assumed association of the naginata and the sōhei is also unclear. Artwork from the late-13th and 14th centuries depict the sōhei with naginata but do not appear to place any special significance to it: the weapons appear as just one of a number of others carried by the monks, and are used by samurai and commoners as well. Depictions of naginata-armed sōhei in earlier periods were created centuries after the fact, and are likely using the naginata as a symbol to distinguish the sōhei from other warriors, rather than giving an accurate portrayal of the events.
After the Ōnin War (1467–1477) in the Muromachi period, large-scale group battles started in which mobilized (foot soldiers) fought on foot and in close quarters, and (spear), (longbow), and (Japanese matchlock) became the main weapons. This made and obsolete on the battlefield, and they were often replaced with the and short, lightweight .
In the Edo period (1603–1867), the hilts of were often cut off and made into or . This practice of cutting off the hilt of an , , , or and remaking it into a shorter or due to changes in tactics is called and was common in Japan at the time. In Japan there is a saying about swords: "No sword made by modifying a or a is dull in cutting" (薙刀（長巻）直しに鈍刀なし). The meaning of this saying is that and are equipment for actual combat, not works of art or offerings to the , and that the sharpness and durability of swords made from their modifications have been proven on the battlefield. | Naginata | Wikipedia | 494 | 153784 | https://en.wikipedia.org/wiki/Naginata | Technology | Polearms | null |
In the peaceful Edo period, weapons' value as battlefield weapons became diminished and their value for martial arts and self-defense rose. The naginata was accepted as a status symbol and self-defense weapon for women of nobility, resulting in the image that "the Naginata is the main weapon used by women".
In the Meiji era, it gained popularity along sword martial arts. From the Taisho era to the post-War era, the naginata became popular as a martial art for women, mainly due to the influence of government policies.
Although associated with considerably smaller numbers of practitioners, a number of "koryu bujutsu" systems (traditional martial arts) which include older and more combative forms of naginatajutsu remain existent, including Suio Ryu, Araki Ryu, Tendo Ryu, Jikishinkage ryu, Higo Koryu, Tenshin Shoden Katori Shinto Ryu, Toda-ha Buko Ryu, and Yoshin ryu, some of which have authorized representatives outside Japan.
Contemporary construction
In contemporary naginatajutsu, two types of practice naginata are in common use.
The naginata used in atarashii naginata (新しいなぎなた), the shiai-yo, has an oak shaft and a bamboo "blade" (habu). It is used for practice, forms competitions, and sparring. It is between and in length and must weigh over . The "blade" is replaceable. They are often broken or damaged during sparring and can be quickly replaced, being attached to the shaft with tape.
The naginata used by koryū practitioners has an oak shaft and blade, carved from a single piece of wood, and may incorporate a disc-shaped guard (tsuba). It is called a kihon-yo.
Contemporary usage
Naginata can be used to batter, stab, or hook an opponent, but due to their relatively balanced center of mass, are often spun and turned to proscribe a large radius of reach. The curved blade provides a long cutting surface without increasing the overall length of the weapon. | Naginata | Wikipedia | 440 | 153784 | https://en.wikipedia.org/wiki/Naginata | Technology | Polearms | null |
Historically, the naginata was often used by foot soldiers to create space on the battlefield. They have several situational advantages over a sword. Their reach is longer, allowing the wielder to keep out of the reach of opponents. The weight of the weapon gave power to strikes and cuts, even though the weight of the weapon is usually thought of as a disadvantage. The weight at the end of the shaft (ishizuki), and the shaft itself (ebu) can be used offensively and defensively.
The martial art of wielding the naginata is known as naginatajutsu. Most naginata practice today is in a modernised form, a gendai budō called atarashii Naginata ("new Naginata"), which is organized into regional, national, and international federations, who hold competitions and award ranks. Use of the naginata is also taught within the Bujinkan and in some koryū schools such as Suio Ryu and Tendō-ryū.
Naginata practitioners wear an uwagi, obi, and hakama, similar to that worn by kendo practitioners, although the uwagi is generally white. For sparring, armor known as bōgu is worn. Bōgu for naginatajutsu adds and the have a singulated index finger, unlike the mitten-style gloves used for kendo.
Gallery | Naginata | Wikipedia | 290 | 153784 | https://en.wikipedia.org/wiki/Naginata | Technology | Polearms | null |
Orion is a prominent set of stars visible during winter in the northern celestial hemisphere. It is one of the 88 modern constellations; it was among the 48 constellations listed by the 2nd-century astronomer Ptolemy. It is named after a hunter in Greek mythology.
Orion is most prominent during winter evenings in the Northern Hemisphere, as are five other constellations that have stars in the Winter Hexagon asterism. Orion's two brightest stars, Rigel (β) and Betelgeuse (α), are both among the brightest stars in the night sky; both are supergiants and slightly variable. There are a further six stars brighter than magnitude 3.0, including three making the short straight line of the Orion's Belt asterism. Orion also hosts the radiant of the annual Orionids, the strongest meteor shower associated with Halley's Comet, and the Orion Nebula, one of the brightest nebulae in the sky.
Characteristics
Orion is bordered by Taurus to the northwest, Eridanus to the southwest, Lepus to the south, Monoceros to the east, and Gemini to the northeast. Covering 594 square degrees, Orion ranks twenty-sixth of the 88 constellations in size. The constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of 26 sides. In the equatorial coordinate system, the right ascension coordinates of these borders lie between and , while the declination coordinates are between and . The constellation's three-letter abbreviation, as adopted by the International Astronomical Union in 1922, is "Ori".
Orion is most visible in the evening sky from January to April, winter in the Northern Hemisphere, and summer in the Southern Hemisphere. In the tropics (less than about 8° from the equator), the constellation transits at the zenith. | Orion (constellation) | Wikipedia | 376 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
In the period May–July (summer in the Northern Hemisphere, winter in the Southern Hemisphere), Orion is in the daytime sky and thus invisible at most latitudes. However, for much of Antarctica in the Southern Hemisphere's winter months, the Sun is below the horizon even at midday. Stars (and thus Orion, but only the brightest stars) are then visible at twilight for a few hours around local noon, just in the brightest section of the sky low in the North where the Sun is just below the horizon. At the same time of day at the South Pole itself (Amundsen–Scott South Pole Station), Rigel is only 8° above the horizon, and the Belt sweeps just along it. In the Southern Hemisphere's summer months, when Orion is normally visible in the night sky, the constellation is actually not visible in Antarctica because the sun does not set at that time of year south of the Antarctic Circle.
In countries close to the equator (e.g., Kenya, Indonesia, Colombia, Ecuador), Orion appears overhead in December around midnight and in the February evening sky.
Navigational aid
Orion is very useful as an aid to locating other stars. By extending the line of the Belt southeastward, Sirius (α CMa) can be found; northwestward, Aldebaran (α Tau). A line eastward across the two shoulders indicates the direction of Procyon (α CMi). A line from Rigel through Betelgeuse points to Castor and Pollux (α Gem and β Gem). Additionally, Rigel is part of the Winter Circle asterism. Sirius and Procyon, which may be located from Orion by following imaginary lines (see map), also are points in both the Winter Triangle and the Circle.
Features
Orion's seven brightest stars form a distinctive hourglass-shaped asterism, or pattern, in the night sky. Four stars—Rigel, Betelgeuse, Bellatrix, and Saiph—form a large roughly rectangular shape, at the center of which lies the three stars of Orion's Belt—Alnitak, Alnilam, and Mintaka. His head is marked by an additional 8th star called Meissa, which is fairly bright to the observer. Descending from the "belt" is a smaller line of three stars, Orion's Sword (the middle of which is in fact not a star but the Orion Nebula), also known as the hunter's sword. | Orion (constellation) | Wikipedia | 507 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
Many of the stars are luminous hot blue supergiants, with the stars of the belt and sword forming the Orion OB1 association. Standing out by its red hue, Betelgeuse may nevertheless be a runaway member of the same group. | Orion (constellation) | Wikipedia | 49 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
Bright stars
Betelgeuse, also designated Alpha Orionis, is a massive M-type red supergiant star nearing the end of its life. It is the second brightest star in Orion, and is a semiregular variable star. It serves as the "right shoulder" of the hunter (assuming that he is facing the observer). It is generally the eleventh brightest star in the night sky, but this has varied between being the tenth brightest to the 23rd brightest by the end of 2019. The end of its life is expected to result in a supernova explosion that will be highly visible from Earth, possibly outshining the Earth's moon and being visible during the day. This is most likely to occur within the next 100,000 years.
Rigel, also known as Beta Orionis, is a B-type blue supergiant that is the seventh brightest star in the night sky. Similar to Betelgeuse, Rigel is fusing heavy elements in its core and will pass its supergiant stage soon (on an astronomical timescale), either collapsing in the case of a supernova or shedding its outer layers and turning into a white dwarf. It serves as the left foot of the hunter.
Bellatrix is designated Gamma Orionis by Johann Bayer. It is the twenty-seventh brightest star in the night sky. Bellatrix is considered a B-type blue giant, though it is too small to explode in a supernova. Bellatrix's luminosity is derived from its high temperature rather than a large radius. Bellatrix marks Orion's left shoulder and it means the "female warrior", and is sometimes known colloquially as the "Amazon Star". It is the closest major star in Orion at only 244.6 light years from our solar system.
Mintaka is designated Delta Orionis, despite being the faintest of the three stars in Orion's Belt. Its name means "the belt". It is a multiple star system, composed of a large B-type blue giant and a more massive O-type main-sequence star. The Mintaka system constitutes an eclipsing binary variable star, where the eclipse of one star over the other creates a dip in brightness. Mintaka is the westernmost of the three stars of Orion's Belt, as well as the northernmost. | Orion (constellation) | Wikipedia | 475 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
Alnilam is designated Epsilon Orionis and is named for the Arabic phrase meaning "string of pearls". It is the middle and brightest of the three stars of Orion's Belt. Alnilam is a B-type blue supergiant; despite being nearly twice as far from the Sun as the other two belt stars, its luminosity makes it nearly equal in magnitude. Alnilam is losing mass quickly, a consequence of its size. It is the farthest major star in Orion at 1,344 light years.
Alnitak, meaning "the girdle", is designated Zeta Orionis, and is the easternmost star in Orion's Belt. It is a triple star system, with the primary star being a hot blue supergiant and the brightest class O star in the night sky.
Saiph is designated Kappa Orionis by Bayer, and serves as Orion's right foot. It is of a similar distance and size to Rigel, but appears much fainter. It means the "sword of the giant"
Meissa is designated Lambda Orionis, forms Orion's head, and is a multiple star with a combined apparent magnitude of 3.33. Its name means the "shining one". | Orion (constellation) | Wikipedia | 252 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
Belt
Orion's Belt or The Belt of Orion is an asterism within the constellation. It consists of the three bright stars Zeta (Alnitak), Epsilon (Alnilam), and Delta (Mintaka). Alnitak is around 800 light years away from earth and is 100,000 times more luminous than the Sun and shines with magnitude 1.8; much of its radiation is in the ultraviolet range, which the human eye cannot see. Alnilam is approximately 2,000 light years away from Earth, shines with magnitude 1.70, and with ultraviolet light is 375,000 times more luminous than the Sun. Mintaka is 915 light years away and shines with magnitude 2.21. It is 90,000 times more luminous than the Sun and is a double star: the two orbit each other every 5.73 days. In the Northern Hemisphere, Orion's Belt is best visible in the night sky during the month of January around 9:00 pm, when it is approximately around the local meridian.
Just southwest of Alnitak lies Sigma Orionis, a multiple star system composed of five stars that have a combined apparent magnitude of 3.7 and lying 1150 light years distant. Southwest of Mintaka lies the quadruple star Eta Orionis.
Sword
Orion's Sword contains the Orion Nebula, the Messier 43 nebula, the Running Man Nebula, and the stars Theta Orionis, Iota Orionis, and 42 Orionis.
Head
Three stars comprise a small triangle that marks the head. The apex is marked by Meissa (Lambda Orionis), a hot blue giant of spectral type O8 III and apparent magnitude 3.54, which lies some 1100 light years distant. Phi-1 and Phi-2 Orionis make up the base. Also nearby is the very young star FU Orionis.
Club
Stretching north from Betelgeuse are the stars that make up Orion's club. Mu Orionis marks the elbow, Nu and Xi mark the handle of the club, and Chi1 and Chi2 mark the end of the club. Just east of Chi1 is the Mira-type variable red giant U Orionis.
Shield
West from Bellatrix lie six stars all designated Pi Orionis (π1 Ori, π2 Ori, π3 Ori, π4 Ori, π5 Ori and π6 Ori) which make up Orion's shield. | Orion (constellation) | Wikipedia | 498 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
Meteor showers
Around 20 October each year the Orionid meteor shower (Orionids) reaches its peak. Coming from the border with the constellation Gemini as many as 20 meteors per hour can be seen. The shower's parent body is Halley's Comet.
Deep-sky objects
Hanging from Orion's belt is his sword, consisting of the multiple stars θ1 and θ2 Orionis, called the Trapezium and the Orion Nebula (M42). This is a spectacular object that can be clearly identified with the naked eye as something other than a star. Using binoculars, its clouds of nascent stars, luminous gas, and dust can be observed. The Trapezium cluster has many newborn stars, including several brown dwarfs, all of which are at an approximate distance of 1,500 light-years. Named for the four bright stars that form a trapezoid, it is largely illuminated by the brightest stars, which are only a few hundred thousand years old. Observations by the Chandra X-ray Observatory show both the extreme temperatures of the main stars—up to 60,000 kelvins—and the star forming regions still extant in the surrounding nebula.
M78 (NGC 2068) is a nebula in Orion. With an overall magnitude of 8.0, it is significantly dimmer than the Great Orion Nebula that lies to its south; however, it is at approximately the same distance, at 1600 light-years from Earth. It can easily be mistaken for a comet in the eyepiece of a telescope. M78 is associated with the variable star V351 Orionis, whose magnitude changes are visible in very short periods of time. Another fairly bright nebula in Orion is NGC 1999, also close to the Great Orion Nebula. It has an integrated magnitude of 10.5 and is 1500 light-years from Earth. The variable star V380 Orionis is embedded in NGC 1999.
Another famous nebula is IC 434, the Horsehead Nebula, near ζ Orionis. It contains a dark dust cloud whose shape gives the nebula its name.
NGC 2174 is an emission nebula located 6400 light-years from Earth. | Orion (constellation) | Wikipedia | 433 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
Besides these nebulae, surveying Orion with a small telescope will reveal a wealth of interesting deep-sky objects, including M43, M78, as well as multiple stars including Iota Orionis and Sigma Orionis. A larger telescope may reveal objects such as the Flame Nebula (NGC 2024), as well as fainter and tighter multiple stars and nebulae. Barnard's Loop can be seen on very dark nights or using long-exposure photography.
All of these nebulae are part of the larger Orion molecular cloud complex, which is located approximately 1,500 light-years away and is hundreds of light-years across. It is one of the most intense regions of stellar formation visible within our galaxy.
History and mythology
The distinctive pattern of Orion is recognized in numerous cultures around the world, and many myths are associated with it. Orion is used as a symbol in the modern world.
Ancient Near East
The Babylonian star catalogues of the Late Bronze Age name Orion , "The Heavenly Shepherd" or "True Shepherd of Anu" – Anu being the chief god of the heavenly realms. The Babylonian constellation is sacred to Papshukal and Ninshubur, both minor gods fulfilling the role of 'messenger to the gods'. Papshukal is closely associated with the figure of a walking bird on Babylonian boundary stones, and on the star map the figure of the Rooster is located below and behind the figure of the True Shepherd—both constellations represent the herald of the gods, in his bird and human forms respectively.
In ancient Egypt, the stars of Orion were regarded as a god, called Sah. Because Orion rises before Sirius, the star whose heliacal rising was the basis for the Solar Egyptian calendar, Sah was closely linked with Sopdet, the goddess who personified Sirius. The god Sopdu is said to be the son of Sah and Sopdet. Sah is syncretized with Osiris, while Sopdet is syncretized with Osiris' mythological wife, Isis. In the Pyramid Texts, from the 24th and 23rd centuries BC, Sah is one of many gods whose form the dead pharaoh is said to take in the afterlife.
The Armenians identified their legendary patriarch and founder Hayk with Orion. Hayk is also the name of the Orion constellation in the Armenian translation of the Bible. | Orion (constellation) | Wikipedia | 480 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
The Bible mentions Orion three times, naming it "Kesil" (כסיל, literally – fool). Though, this name perhaps is etymologically connected with "Kislev", the name for the ninth month of the Hebrew calendar (i.e. November–December), which, in turn, may derive from the Hebrew root K-S-L as in the words "kesel, kisla" (כֵּסֶל, כִּסְלָה, hope, positiveness), i.e. hope for winter rains.: Job 9:9 ("He is the maker of the Bear and Orion"), Job 38:31 ("Can you loosen Orion's belt?"), and Amos 5:8 ("He who made the Pleiades and Orion").
In ancient Aram, the constellation was known as Nephîlā′, the Nephilim are said to be Orion's descendants.
Greco-Roman antiquity
In Greek mythology, Orion was a gigantic, supernaturally strong hunter, born to Euryale, a Gorgon, and Poseidon (Neptune), god of the sea. One myth recounts Gaia's rage at Orion, who dared to say that he would kill every animal on Earth. The angry goddess tried to dispatch Orion with a scorpion. This is given as the reason that the constellations of Scorpius and Orion are never in the sky at the same time. However, Ophiuchus, the Serpent Bearer, revived Orion with an antidote. This is said to be the reason that the constellation of Ophiuchus stands midway between the Scorpion and the Hunter in the sky.
The constellation is mentioned in Horace's Odes (Ode 3.27.18), Homer's Odyssey (Book 5, line 283) and Iliad, and Virgil's Aeneid (Book 1, line 535)
Middle East
In medieval Muslim astronomy, Orion was known as al-jabbar, "the giant". Orion's sixth brightest star, Saiph, is named from the Arabic, saif al-jabbar, meaning "sword of the giant".
China
In China, Orion was one of the 28 lunar mansions Sieu (Xiù) (宿). It is known as Shen (參), literally meaning "three", for the stars of Orion's Belt. (See Chinese constellations) | Orion (constellation) | Wikipedia | 500 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
The Chinese character 參 (pinyin shēn) originally meant the constellation Orion (); its Shang dynasty version, over three millennia old, contains at the top a representation of the three stars of Orion's belt atop a man's head (the bottom portion representing the sound of the word was added later).
India
The Rigveda refers to the Orion Constellation as Mriga (The Deer).
Nataraja, 'the cosmic dancer', is often interpreted as the representation of Orion. Rudra, the Rigvedic form of Shiva, is the presiding deity of Ardra nakshatra (Betelgeuse) of Hindu astrology.
The Jain Symbol carved in Udayagiri and Khandagiri Caves, India in 1st century BCE has striking resemblance with Orion.
Bugis sailors identified the three stars in Orion's Belt as tanra tellué, meaning "sign of three".
European folklore
In old Hungarian tradition, Orion is known as "Archer" (Íjász), or "Reaper" (Kaszás). In recently rediscovered myths, he is called Nimrod (Hungarian: Nimród), the greatest hunter, father of the twins Hunor and Magor. The π and o stars (on upper right) form together the reflex bow or the lifted scythe. In other Hungarian traditions, Orion's belt is known as "Judge's stick" (Bírópálca).
In Scandinavian tradition, Orion's belt was known as "Frigg's Distaff" (friggerock) or "Freyja's distaff".
The Finns call Orion's belt and the stars below it "Väinämöinen's scythe" (Väinämöisen viikate). Another name for the asterism of Alnilam, Alnitak and Mintaka is "Väinämöinen's Belt" (Väinämöisen vyö) and the stars "hanging" from the belt as "Kaleva's sword" (Kalevanmiekka).
In Siberia, the Chukchi people see Orion as a hunter; an arrow he has shot is represented by Aldebaran (Alpha Tauri), with the same figure as other Western depictions. | Orion (constellation) | Wikipedia | 459 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
There are claims in popular media that the Adorant from the Geißenklösterle cave, an ivory carving estimated to be 35,000 to 40,000 years old, is the first known depiction of the constellation. Scholars dismiss such interpretations, saying that perceived details such as a belt and sword derive from preexisting features in the grain structure of the ivory.
Americas
The Seri people of northwestern Mexico call the three stars in the belt of Orion Hapj (a name denoting a hunter) which consists of three stars: Hap (mule deer), Haamoja (pronghorn), and Mojet (bighorn sheep). Hap is in the middle and has been shot by the hunter; its blood has dripped onto Tiburón Island.
The same three stars are known in Spain and most of Latin America as "Las tres Marías" (Spanish for "The Three Marys").
In Puerto Rico, the three stars are known as the "Los Tres Reyes Magos" (Spanish for The three Wise Men).
The Ojibwa (Chippewa) Native Americans call this constellation Kabibona'kan, the Winter Maker, as its presence in the night sky heralds winter.
To the Lakota Native Americans, Tayamnicankhu (Orion's Belt) is the spine of a bison. The great rectangle of Orion is the bison's ribs; the Pleiades star cluster in nearby Taurus is the bison's head; and Sirius in Canis Major, known as Tayamnisinte, is its tail. Another Lakota myth mentions that the bottom half of Orion, the Constellation of the Hand, represented the arm of a chief that was ripped off by the Thunder People as a punishment from the gods for his selfishness. His daughter offered to marry the person who can retrieve his arm from the sky, so the young warrior Fallen Star (whose father was a star and whose mother was human) returned his arm and married his daughter, symbolizing harmony between the gods and humanity with the help of the younger generation. The index finger is represented by Rigel; the Orion Nebula is the thumb; the Belt of Orion is the wrist; and the star Beta Eridani is the pinky finger.
Austronesian | Orion (constellation) | Wikipedia | 468 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
The seven primary stars of Orion make up the Polynesian constellation Heiheionakeiki which represents a child's string figure similar to a cat's cradle. Several precolonial Filipinos referred to the belt region in particular as "balatik" (ballista) as it resembles a trap of the same name which fires arrows by itself and is usually used for catching pigs from the bush. Spanish colonization later led to some ethnic groups referring to Orion's belt as "Tres Marias" or "Tatlong Maria."
In Māori tradition, the star Rigel (known as Puanga or Puaka) is closely connected with the celebration of Matariki. The rising of Matariki (the Pleiades) and Rigel before sunrise in midwinter marks the start of the Māori year.
In Javanese culture, the constellation is often called Lintang Waluku or Bintang Bajak, referring to the shape of a paddy field plow.
Contemporary symbolism
The imagery of the belt and sword has found its way into popular western culture, for example in the form of the shoulder insignia of the 27th Infantry Division of the United States Army during both World Wars, probably owing to a pun on the name of the division's first commander, Major General John F. O'Ryan.
The film distribution company Orion Pictures used the constellation as its logo.
Depictions
In artistic renderings, the surrounding constellations are sometimes related to Orion: he is depicted standing next to the river Eridanus with his two hunting dogs Canis Major and Canis Minor, fighting Taurus. He is sometimes depicted hunting Lepus the hare. He sometimes is depicted to have a lion's hide in his hand. | Orion (constellation) | Wikipedia | 348 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
There are alternative ways to visualise Orion. From the Southern Hemisphere, Orion is oriented south-upward, and the belt and sword are sometimes called the saucepan or pot in Australia and New Zealand. Orion's Belt is called Drie Konings (Three Kings) or the Drie Susters (Three Sisters) by Afrikaans speakers in South Africa and are referred to as les Trois Rois (the Three Kings) in Daudet's Lettres de Mon Moulin (1866). The appellation Driekoningen (the Three Kings) is also often found in 17th- and 18th-century Dutch star charts and seaman's guides. The same three stars are known in Spain, Latin America, and the Philippines as "Las Tres Marías" (The Three Marys), and as "Los Tres Reyes Magos" (The three Wise Men) in Puerto Rico.
Even traditional depictions of Orion have varied greatly. Cicero drew Orion in a similar fashion to the modern depiction. The Hunter held an unidentified animal skin aloft in his right hand; his hand was represented by Omicron2 Orionis and the skin was represented by the 5 stars designated Pi Orionis. Kappa and Beta Orionis represented his left and right knees, while Eta and Lambda Leporis were his left and right feet, respectively. As in the modern depiction, Delta, Epsilon, and Zeta represented his belt. His left shoulder was represented by Alpha Orionis, and Mu Orionis made up his left arm. Lambda Orionis was his head and Gamma, his right shoulder. The depiction of Hyginus was similar to that of Cicero, though the two differed in a few important areas. Cicero's animal skin became Hyginus's shield (Omicron and Pi Orionis), and instead of an arm marked out by Mu Orionis, he holds a club (Chi Orionis). His right leg is represented by Theta Orionis and his left leg is represented by Lambda, Mu, and Epsilon Leporis. Further Western European and Arabic depictions have followed these two models.
Future | Orion (constellation) | Wikipedia | 427 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
Orion is located on the celestial equator, but it will not always be so located due to the effects of precession of the Earth's axis. Orion lies well south of the ecliptic, and it only happens to lie on the celestial equator because the point on the ecliptic that corresponds to the June solstice is close to the border of Gemini and Taurus, to the north of Orion. Precession will eventually carry Orion further south, and by AD 14000, Orion will be far enough south that it will no longer be visible from the latitude of Great Britain.
Further in the future, Orion's stars will gradually move away from the constellation due to proper motion. However, Orion's brightest stars all lie at a large distance from the Earth on an astronomical scale—much farther away than Sirius, for example. Orion will still be recognizable long after most of the other constellations—composed of relatively nearby stars—have distorted into new configurations, with the exception of a few of its stars eventually exploding as supernovae, for example Betelgeuse, which is predicted to explode sometime in the next million years. | Orion (constellation) | Wikipedia | 232 | 153797 | https://en.wikipedia.org/wiki/Orion%20%28constellation%29 | Physical sciences | Constellations | null |
Spandex, Lycra, or elastane is a synthetic fiber known for its exceptional elasticity. It is a polyether-polyurea copolymer that was invented in 1958 by chemist Joseph Shivers at DuPont.
Name
The name spandex, which is an anagram of the word "expands", is the preferred name in North America. In continental Europe, it is referred to by variants of elastane. It is primarily known as Lycra in the UK, Ireland, Portugal, Spain, Latin America, Australia, and New Zealand.
Brand names for spandex include Lycra (made by The Lycra Company, previously a division of DuPont Textiles and Interiors), Elaspan (The Lycra Company), Acepora (Taekwang Group), Creora (Hyosung), INVIYA (Indorama Corporation), ROICA and Dorlastan (Asahi Kasei), Linel (Fillattice), and ESPA (Toyobo).
Production
Unlike many other synthetic fibers, spandex cannot be melt-processed because the polymer degrades upon melting. Spandex fibers are produced by several spinning technologies. Typically, a concentrated solution of the polymer is drawn through spinnerets at temperatures where the solvent evaporates.
Spandex is mainly composed of a polyurea derived from the reaction of a diol and a diisocyanate. Two classes of spandex are defined by the "macrodiols". One class of macrodiols is the oligomer produced from tetrahydrofuran (i.e. polytetrahydrofuran). Another class of diols, the so-called ester diols, are oligomers derived from condensation of adipic acid and glycols. Spandex produced from the ester diols is more resilient photochemically and to chlorinated water. Almost always, the diisocyanate is methylenebis(phenyl isocyanate). The key linking reaction is formation or the urea (aka urethane):
The polyurea is usually treated with various diamines, which function as chain extenders. | Spandex | Wikipedia | 475 | 153882 | https://en.wikipedia.org/wiki/Spandex | Technology | Fabrics and fibers | null |
Function
The exceptional elasticity of spandex fibers increases the clothing's pressure comfort, enhancing the ease of body movements. Pressure comfort is the response towards clothing by the human body's pressure receptors (mechanoreceptors present in skin sensory cells). The sensation response is affected mainly by the stretch, snug, loose, heavy, lightweight, soft, and stiff structure of the material.
The elasticity and strength (stretching up to five times its length) of spandex has been incorporated into a wide range of garments, especially in skin-tight garments. A benefit of spandex is its significant strength and elasticity and its ability to return to the original shape after stretching and faster drying than ordinary fabrics. For clothing, spandex is usually mixed with cotton or polyester, and accounts for a small percentage of the final fabric, which therefore retains most of the look and feel of the other fibers. An estimated 80% of clothing sold in the United States contained spandex in 2010.
Gallery
History
The easy condensation of diols and diisocyanates was recognized in the 1930s as the result of work by Otto Bayer. Fibers suitable for replacing nylon were not created from urethanes, but instead this theme led to a family of specialized elastic fabrics.
In the post-World War II era, DuPont Textiles Fibers Department, formed in 1952, became the most profitable division of DuPont, dominating the synthetic fiber market worldwide. At this time, women began to emerge as a significant group of consumers because of their need for underwear and hosiery. After conducting market research to find out what women wanted from textiles, DuPont began developing fibers to meet such needs—including a better fiber for women's girdles, which were commonly made of rubber at the time.
In the early 1950s chemist Joseph C. Shivers modified Dacron polyester, producing an elastic fiber that could withstand high temperatures.
Lycra brand
To distinguish its brand of spandex fiber, DuPont chose the trade name Lycra (originally called Fiber K). DuPont launched an extensive publicity campaign for its Lycra brand, taking advertisements and full-page ads in top women's magazines. Audrey Hepburn helped catapult the brand on and off-screen during this time; models and actresses like Joan Collins and Ann-Margret followed Hepburn's aesthetic by posing in Lycra clothing for photo shoots and magazine covers. | Spandex | Wikipedia | 500 | 153882 | https://en.wikipedia.org/wiki/Spandex | Technology | Fabrics and fibers | null |
By the mid-1970s, with the emergence of the women's liberation movement, girdle sales began to drop as they came to be associated with anti-independence and emblematic of an era that was quickly passing away. In response, DuPont marketed Lycra as the aerobic fitness movement emerged in the 1970s. The association of Lycra with fitness had been established at the 1968 Winter Olympic Games, when the French ski team wore Lycra garments. The fiber came to be especially popular in mid-thigh-length shorts worn by cyclists.
By the 1980s, the fitness trend had reached its height in popularity and fashionistas began wearing shorts on the street. Spandex proved such a popular fiber in the garment industry that, by 1987, DuPont had trouble meeting worldwide demand. In the 1990s a variety of other items made with spandex proved popular, including a successful line of body-shaping foundation garments sold under the trade name Bodyslimmers. As the decade progressed, shirts, pants, dresses, and even shoes were being made with spandex blends, and mass-market retailers like Banana Republic were even using it for menswear.
In 2019, control of the Lycra Company was sold by Koch Industries to Shandong Ruyi.
Environmental impact
Most clothes containing spandex are difficult to recycle. Even a 5% inclusion of spandex will render the fabric incompatible with most mechanical recycling machines. | Spandex | Wikipedia | 296 | 153882 | https://en.wikipedia.org/wiki/Spandex | Technology | Fabrics and fibers | null |
Invisibility is the state of an object that cannot be seen. An object in this state is said to be invisible (literally, "not visible"). The phenomenon is studied by physics and perceptual psychology.
Since objects can be seen by light from a source reflecting off their surfaces and hitting the viewer's eyes, the most natural form of invisibility (whether real or fictional) is an object that neither reflects nor absorbs light (that is, it allows light to pass through it). This is known as
transparency, and is seen in many naturally occurring materials (although no naturally occurring material is 100% transparent).
Invisibility perception depends on several optical and visual factors. For example, invisibility depends on the eyes of the observer and/or the instruments used. Thus an object can be classified as "invisible" to a person, animal, instrument, etc. In research on sensorial perception it has been shown that invisibility is perceived in cycles.
Invisibility is often considered to be the supreme form of camouflage, as it does not reveal to the viewer any kind of vital signs, visual effects, or any frequencies of the electromagnetic spectrum detectable to the human eye, instead making use of radio, infrared or ultraviolet wavelengths.
In illusion optics, invisibility is a special case of illusion effects: the illusion of free space.
The term is often used in fantasy and science fiction, where objects cannot be seen by means of magic or hypothetical technology.
Practical efforts
Technology can be used theoretically or practically to render real-world objects invisible.
Making use of a real-time image displayed on a wearable display, it is possible to create a see-through effect. This is known as active camouflage. Though stealth technology is declared to be invisible to radar, all officially disclosed applications of the technology can only reduce the size and/or clarity of the signature detected by radar.
In 2003 the Chilean scientist Gunther Uhlmann postulates the first mathematical equations to create invisible materials.
In 2006, a team effort of researchers from Britain and the US announced the development of a real cloak of invisibility, an artificially made meta material that is invisible to the microwave spectrum, though it is only in its first stages.
In filmmaking, people, objects, or backgrounds can be made to look invisible on camera through a process known as chroma keying. | Invisibility | Wikipedia | 483 | 153911 | https://en.wikipedia.org/wiki/Invisibility | Physical sciences | Optics | Physics |
Engineers and scientists have performed various kinds of research to investigate the possibility of finding ways to create real optical invisibility (cloaks) for objects. Methods are typically based on implementing the theoretical techniques of transformation optics, which have given rise to several theories of cloaking.
Currently, a practical cloaking device does not exist. A 2006 theoretical work predicts that the imperfections are minor, and metamaterials may make real-life "cloaking devices" practical. The technique is predicted to be applied to radio waves within five years, and the distortion of visible light is an eventual possibility. The theory that light waves can be acted upon the same way as radio waves is now a popular idea among scientists. The agent can be compared to a stone in a river, around which water passes, but slightly down-stream leaves no trace of the stone. Comparing light waves to the water, and whatever object that is being "cloaked" to the stone, the goal is to have light waves pass around that object, leaving no visible aspects of it, possibly not even a shadow. This is the technique depicted in the 2000 television portrayal of The Invisible Man.
Two teams of scientists worked separately to create two "Invisibility Cloaks" from 'metamaterials' engineered at the nanoscale level. They demonstrated for the first time the possibility of cloaking three-dimensional (3-D) objects with artificially engineered materials that redirect radar, light or other waves around an object. While one uses a type of fishnet of metal layers to reverse the direction of light, the other uses tiny silver wires. Xiang Zhang, of the University of California, Berkeley said: "In the case of invisibility cloaks or shields, the material would need to curve light waves completely around the object like a river flowing around a rock. An observer looking at the cloaked object would then see light from behind it, making it seem to disappear." | Invisibility | Wikipedia | 396 | 153911 | https://en.wikipedia.org/wiki/Invisibility | Physical sciences | Optics | Physics |
UC Berkeley researcher Jason Valentine's team made a material that affects light near the visible spectrum, in a region used in fibre optics: 'Instead of the fish appearing to be slightly ahead of where it is in the water, it would actually appear to be above the water's surface. For a metamaterial to produce negative refraction, it must have a structural array smaller than the wavelength of the electromagnetic radiation being used." Valentine's team created their 'fishnet' material by stacking silver and metal dielectric layers on top of each other and then punching holes through them. The other team used an oxide template and grew silver nanowires inside porous aluminum oxide at tiny distances apart, smaller than the wavelength of visible light. This material refracts visible light.
The Imperial College London research team achieved results with microwaves. An invisibility cloak layout of a copper cylinder was produced in May, 2008, by physicist Professor Sir John Pendry. Scientists working with him at Duke University in the US put the idea into practice.
Pendry, who theorized the invisibility cloak "as a joke" to illustrate the potential of metamaterials, said in an interview in August 2011 that grand, theatrical manifestations of his idea are probably overblown: "I think it’s pretty sure that any cloak that Harry Potter would recognize is not on the table. You could dream up some theory, but the very practicality of making it would be so impossible. But can you hide things from light? Yes. Can you hide things which are a few centimeters across? Yes. Is the cloak really flexible and flappy? No. Will it ever be? No. So you can do quite a lot of things, but there are limitations. There are going to be some disappointed kids around, but there might be a few people in industry who are very grateful for it."
In Turkey in 2009, Bilkent University Search Center Of Nanotechnology researches explained and published in New Journal of Physics that they achieved to make invisibility real in practice using nanotechnology making an object invisible with no shadows etc. next to perfect transparent scene by producing nanotechnologic material that can also be produced like a suit anyone can wear. | Invisibility | Wikipedia | 457 | 153911 | https://en.wikipedia.org/wiki/Invisibility | Physical sciences | Optics | Physics |
In 2019, Hyperstealth Biotechnology has patented the technology behind a material that bends light to make people and objects near invisible to the naked eye. The material, called Quantum Stealth, is currently still in the prototyping stage, but was developed by the company's CEO Guy Cramer primarily for military purposes, to conceal agents and equipment such as tanks and jets in the field. Unlike traditional camouflage materials, which are limited to specific conditions such as forests or deserts, according to Cramer this "invisibility cloak" works in any environment or season, at any time of day. This is despite its actual application requiring artificial backgrounds made up of horizontal lines.
Psychological
A person can be described as invisible if others refuse to see them or routinely overlook them. The term was used in this manner in the title of the book Invisible Man, by Ralph Ellison, in reference to the protagonist, likely modeled after the author, being overlooked on account of his status as an African American. This is supported by the quote taken from the Prologue, "I am invisible, understand, simply because people refuse to see me." (Prologue.1)
Fictional use
In fiction, people or objects can be rendered completely invisible by several means:
Magical objects such as rings, cloaks and amulets can be worn to grant the wearer permanent invisibility (or temporary invisibility until the object is taken off).
Magical potions can be consumed to grant temporary or permanent invisibility.
Magic spells can be cast on people or objects, usually giving temporary invisibility.
Some mythical creatures can make themselves invisible at will, such as in some tales in which leprechauns or Chinese dragons can shrink so much that humans cannot see them.
In science fiction, the idea of a "cloaking device".
In some works, the power of magic creates an effective means of invisibility by distracting anyone who might notice the character. But since the character is not truly invisible, the effect could be betrayed by mirrors or other reflective surfaces.
Where magical invisibility is concerned, the issue may arise of whether the clothing worn by and any items carried by the invisible being are also rendered invisible. In general they are also regarded as being invisible, but in some instances clothing remains visible and must be removed for the full invisibility effect. | Invisibility | Wikipedia | 468 | 153911 | https://en.wikipedia.org/wiki/Invisibility | Physical sciences | Optics | Physics |
Chlamydia is a genus of pathogenic Gram-negative bacteria that are obligate intracellular parasites. Chlamydia infections are the most common bacterial sexually transmitted diseases in humans and are the leading cause of infectious blindness worldwide.
Species include Chlamydia trachomatis (a human pathogen), Ch. suis (affects only swine), and Ch. muridarum (affects only mice and hamsters). Humans mainly contract Ch. trachomatis, Ch. pneumoniae, Ch. abortus, and Ch. psittaci.
Classification
Because of Chlamydias unique developmental cycle, it was taxonomically classified in a separate order. Chlamydia is part of the order Chlamydiales, family Chlamydiaceae.
In the early 1990s six species of Chlamydia were known. A major re-description of the Chlamydiales order in 1999, using the then new techniques of DNA analysis, split three of the species from the genus Chlamydia and reclassified them in the then newly created genus Chlamydophila, and also added three new species to this genus. In 2001 many bacteriologists strongly objected to the reclassification, although in 2006 some scientists still supported the distinctness of Chlamydophila. In 2009 the validity of Chlamydophila was challenged by newer DNA analysis techniques, leading to a proposal to "reunite the Chlamydiaceae into a single genus, Chlamydia". This appears to have been accepted by the community, bringing the number of (valid) Chlamydia species up to 9. Many probable species were subsequently isolated, but no one bothered to name them. In 2013 a 10th species was added, Ch. ibidis, known only from feral sacred ibis in France. Two more species were added in 2014 (but validated 2015): Ch. avium which infects pigeons and parrots, and Ch. gallinacea infecting chickens, guinea fowl and turkeys. Ch. abortus was added in 2015, and the Chlamydophila species reclassified. A number of new species were originally classified as aberrant strains of Ch. psittaci | Chlamydia (genus) | Wikipedia | 463 | 11688148 | https://en.wikipedia.org/wiki/Chlamydia%20%28genus%29 | Biology and health sciences | Gram-negative bacteria | Plants |
Genomes
Chlamydia species have genomes around 1.0 to 1.3 megabases in length. Most encode ~900 to 1050 proteins. Some species also contain a DNA plasmids or phage genomes (see Table). The elementary body contains an RNA polymerase responsible for the transcription of the DNA genome after entry into the host cell cytoplasm and the initiation of the growth cycle. Ribosomes and ribosomal subunits are found in these bodies.
Table 1. Genome features of selected Chlamydia species and strains. MoPn is a mouse pathogen while strain "D" is a human pathogen. About 80% of the genes in Ch. trachomatis and Ch. pneumoniae are orthologs. Adapted after Read et al. 2000
Developmental cycle
Chlamydia may be found in the form of an elementary body and a reticulate body. The elementary body is the nonreplicating infectious particle that is released when infected cells rupture. It is responsible for the bacteria's ability to spread from person to person and is analogous to a spore. The elementary body may be 0.25 to 0.30 μm in diameter. This form is covered by a rigid cell wall (hence the combining form chlamyd- in the genus name). The elementary body induces its own endocytosis upon exposure to target cells. One phagolysosome usually produces an estimated 100–1000 elementary bodies. | Chlamydia (genus) | Wikipedia | 307 | 11688148 | https://en.wikipedia.org/wiki/Chlamydia%20%28genus%29 | Biology and health sciences | Gram-negative bacteria | Plants |
Chlamydia may also take the form of a reticulate body, which is in fact an intracytoplasmic form, highly involved in the process of replication and growth of these bacteria. The reticulate body is slightly larger than the elementary body and may reach up to 0.6 μm in diameter with a minimum of 0.5 μm. It does not have a cell wall. When stained with iodine, reticulate bodies appear as inclusions in the cell. The DNA genome, proteins, and ribosomes are retained in the reticulate body. This occurs as a result of the development cycle of the bacteria. The reticular body is basically the structure in which the chlamydial genome is transcribed into RNA, proteins are synthesized, and the DNA is replicated. The reticulate body divides by binary fission to form particles which, after synthesis of the outer cell wall, develop into new infectious elementary body progeny. The fusion lasts about three hours and the incubation period may be up to 21 days. After division, the reticulate body transforms back to the elementary form and is released by the cell by exocytosis.
Studies on the growth cycle of Ch. trachomatis and Ch. psittaci in cell cultures in vitro reveal that the infectious elementary body (EB) develops into a noninfectious reticulate body (RB) within a cytoplasmic vacuole in the infected cell. After the elementary body enters the infected cell, an eclipse phase of 20 hours occurs while the infectious particle develops into a reticulate body. The yield of chlamydial elementary bodies is maximal 36 to 50 hours after infection.
A histone like protein HctA and HctB play role in controlling the differentiation between the two cell types. The expression of HctA is tightly regulated and repressed by small non-coding RNA, IhtA until the late RB to EB re-differentiation. The IhtA RNA is conserved across Chlamydia species. | Chlamydia (genus) | Wikipedia | 416 | 11688148 | https://en.wikipedia.org/wiki/Chlamydia%20%28genus%29 | Biology and health sciences | Gram-negative bacteria | Plants |
Pathology
Most chlamydial infections do not cause symptoms. Symptomatic infections often include a burning sensation when urinating and abdominal or genital pain and discomfort. All people who have engaged in sexual activity with potentially infected individuals may be offered one of several tests to diagnose the condition. Nucleic acid amplification tests (NAAT), which include polymerase chain reaction (PCR), transcription-mediated amplification (TMA), ligase chain reaction (LCR), and strand displacement amplification (SDA), are the most widely used diagnostic test for Chlamydia.
Evolution
Recent phylogenetic studies have revealed that Chlamydia likely shares a common ancestor with cyanobacteria, the group containing the endosymbiont ancestor to the chloroplasts of modern plants, hence, Chlamydia retains unusual plant-like traits, both genetically and physiologically. In particular, the enzyme L,L-diaminopimelate aminotransferase, which is related to lysine production in plants, is also linked with the construction of chlamydial peptidoglycan, which is required for division. The genetic encoding for the enzymes is remarkably similar in plants, cyanobacteria, and Chlamydia, demonstrating a close common ancestry.
Phylogeny | Chlamydia (genus) | Wikipedia | 278 | 11688148 | https://en.wikipedia.org/wiki/Chlamydia%20%28genus%29 | Biology and health sciences | Gram-negative bacteria | Plants |
Indigofera is a large genus of over 750 species of flowering plants belonging to the pea family Fabaceae. They are widely distributed throughout the tropical and subtropical regions of the world.
Description
Indigofera is a varied genus that has shown unique characteristics making it an interesting candidate as a potential perennial crop. Specifically, there is diverse variation among species with a number of unique characteristics. Some examples of this diversity include differences in pericarp thickness, fruit type, and flowering morphology. The unique characteristics it has displayed include potential for mixed smallholder systems with at least one other species and a resilience that allows for constant nitrogen uptake despite varying conditions.
Tree
Species of Indigofera are mostly shrubs, though some are small trees or herbaceous perennials or annuals. The branches are covered with silky hairs. Most of them have pinnate leaves made of three foliolates with short petioles.
Small flowers grow in the leaf axils from long peduncles or spikes, their petals come in hues of red or purple, but there are a few greenish-white and yellow-flowered species. Indigofera flowers have open carpels, their organ primordial is often formed at deeper layers than other eudicots. This variety could have significant implications on its role in an actual perennial polyculture. For example, different flowering morphologies could be artificially selected for in varying directions in order to better fit in different environmental conditions and with different populations of other plants.
Fruit
The fruit is a long, cylindrical legume pod of varying size and shape.
The types of fruit produced by different species of Indigofera can also be divided into broad categories that again show great variation. The three basic types of fruit categories can be separated by their curvature including straight, slightly curved, and falcate (sickle-shaped). In addition, several of the species including Indigofera microcarpa, Indigofera suffruticosa, and Indigofera enneaphylla have shown delayed dehiscence (maturing) of fruits This variation could again allow for artificial selection of the most abundant and nutritious fruit types and shapes. | Indigofera | Wikipedia | 429 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Another way to categorize Indigofera is by its pericarp thickness. The pericarp (the tissue from the ovary that surrounds the seeds) can be categorized as type I, type II, and type III with type I having the thinnest pericarp and fewest layers of schlerenchymatous (stiff) tissue and type III having the thickest pericarp and most schlerenchymatous layers. Despite the previous examples of delayed dehiscence, most fruits of this genus show normal explosive dehiscence to disperse seeds. Similar to fruit shape, the variation in fruit sizes allows for the thickest and most bountiful fruits to be selected.
Uses
Indigo dye
Several species, especially Indigofera tinctoria and Indigofera suffruticosa, are used to produce the dye indigo. Scraps of Indigo-dyed fabric likely dyed with plants from the genus Indigofera discovered at Huaca Prieta predate Egyptian indigo-dyed fabrics by more than 1,500 years. Colonial planters in the Caribbean grew indigo and transplanted its cultivation when they settled in the colony of South Carolina and North Carolina where people of the Tuscarora confederacy adopted the dyeing process for head wraps and clothing. Exports of the crop did not expand until the mid-to late 18th century. When Eliza Lucas Pinckney and enslaved Africans successfully cultivated new strains near Charleston it became the second most important cash crop in the colony (after rice) before the American Revolution. It comprised more than one-third of all exports in value.
The chemical aniline, from which many important dyes are derived, was first synthesized from Indigofera suffruticosa (syn. Indigofera anil, whence the name aniline).
In Indonesia, the Sundanese use Indigofera tinctoria (known locally as tarum or nila) as dye for batik. Marco Polo was the first to report on the preparation of indigo in India. Indigo was quite often used in European easel painting during the Middle Ages.
Species
Indigofera comprises the following species:
Palaeotropical clade
Indigofera argentea Burm.f.
Indigofera atriceps Hook.f. | Indigofera | Wikipedia | 450 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
subsp. atriceps Hook.f.
subsp. glandulosissima (R.E.Fr.) J.B.Gillett
subsp. kaessneri (Baker f.) J.B.Gillett
subsp. ramosa (Cronquist) J.B.Gillett
subsp. rhodesiaca J.B.Gillett
subsp. setosissima (Harms) J.B.Gillett
subsp. ufipaensis J.B.Gillett
Indigofera bainesii Baker
Indigofera basiflora J.B.Gillett
Indigofera biglandulosa J.B.Gillett
Indigofera bracteolata DC.
Indigofera brevicalyx Baker f.
Indigofera brevipatentes
Indigofera colutea (Burm.f.) Merr.—rusty indigo, sticky indigo
Indigofera compressa Lam.
Indigofera congesta Baker
Indigofera demissa Taub.
Indigofera eremophila Thulin
Indigofera erythrogramma Baker
Indigofera gairdnerae Baker f.
Indigofera glabra L.
Indigofera grata E.Mey.
Indigofera hermannioides J.B.Gillett
Indigofera heterotricha DC.
Indigofera heudelotii Baker
Indigofera hilaris Eckl. & Zeyh.
var. hilaris Eckl. & Zeyh.
var. microscypha (Baker) J.B. Gillett
Indigofera inhambanensis Klotzsch
Indigofera kirkii Oliv.
Indigofera leucotricha E.Pritzel
Indigofera macrocalyx Guill. & Perr.
Indigofera microcalyx Baker
Indigofera mildbraediana J.B.Gillett
Indigofera mimosoides Baker
Indigofera monantha Baker f.
Indigofera mooneyi Thulin
Indigofera montoya Spanish Indigo
Indigofera mysorensis DC.
Indigofera nebrowniana J.B.Gillett
Indigofera nigritana Hook.f.
Indigofera nyassica Gilli
Indigofera omissa J.B.Gillett
Indigofera paniculata Pers.
subsp. gazensis (Baker f.) J.B.Gillett
subsp. paniculata Pers.
Indigofera phymatodea Thulin
Indigofera podophylla Harv.
Indigofera poliotes Eckl. & Zeyh. | Indigofera | Wikipedia | 500 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera pulchra Willd.
Indigofera quarrei Cronquist
Indigofera rothii Baker
Indigofera rubroglandulosa Germish.
Indigofera simplicifolia Lam.
Indigofera strobilifera (Hochst.) Baker
subsp. lanuginosa (Baker f.) J.B.Gillett
subsp. strobilifera (Hochst.) Baker
Indigofera suaveolens Jaub. & Spach
Indigofera tanganyikensis Baker f.
Indigofera tetrasperma Pers.
Indigofera trachyphylla Oliv.
Indigofera uniflora Roxb.
Indigofera vohemarensis Baill.
Indigofera wightii Wight & Arn.
Indigofera wituensis Baker f.
Pantropical clade
Indigofera amblyantha Craib
Indigofera amorphoides Jaub. & Spach
Indigofera arrecta A.Rich.—Natal indigo, Bengal indigo, Java indigo
Indigofera articulata Gouan
Indigofera astragalina DC.
Indigofera atropurpurea Hornem.
Indigofera australis Willd.—Australian indigo
Indigofera baumiana Harms
Indigofera binderi Kotschy
Indigofera blanchetiana Benth.
Indigofera bojeri Baker
Indigofera boranica Thulin
Indigofera bosseri Du Puy & Labat
Indigofera boviperda Morrison
Indigofera byobiensis Hosok.
Indigofera caloneura Kurz
Indigofera caroliniana Mill.—Carolina indigo
Indigofera cassioides DC. | Indigofera | Wikipedia | 325 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera cavallii Chiov.
Indigofera coerulea Roxb.
var. coerulea Roxb.
var. monosperma (Santapau) Santapau
var. occidentalis J.B.Gillett & Ali
Indigofera conzattii Rose
Indigofera cuernavacana Rose
Indigofera cylindracea Baker
Indigofera decora Lindl.—Chinese indigo
var. chalara (Craib) Y.Y.Fang & C.Z.Zheng
var. cooperi (Craib) Y.Y.Fang & C.Z.Zheng
var. decora Lindl.
var. ichangensis (Craib) Y.Y.Fang & C.Z.Zheng
Indigofera deightonii J.B.Gillett
subsp. deightonii J.B.Gillett
subsp. rhodesica J.B.Gillett
Indigofera dendroides Jacq.
Indigofera dosua D.Don
var. dosua D.Don
var. simlensis (Ali) Sanjappa
Indigofera emarginella A.Rich.
Indigofera frondosa N.E.Br.
Indigofera frutescens L.f.
Indigofera fulgens Baker
subsp. brachybotrys (Baker) J.B.Gillett
subsp. fulgens Baker
Indigofera galegoides DC.
Indigofera georgei E.Pritz.
Indigofera grandiflora B.H.Choi & S.K.Cho
Indigofera haplophylla F.Muell.
Indigofera hebepetala Baker
var. glabra Ali
var. hebepetala Baker
Indigofera hedyantha Eckl. & Zeyh.
Indigofera heterantha Brandis—Himalayan indigo
Indigofera himalayensis Ali
Indigofera hirsuta L.—hairy indigo, rough hairy indigo
Indigofera homblei Baker f. & Martin
Indigofera ixocarpa Peter G.Wilson & Rowe
Indigofera jucunda Schrire
Indigofera karnatakana Sanjappa
Indigofera kirilowii Maxim ex Palib.—Kirilow's indigo
Indigofera koreana Ohwi—Korean indigo
Indigofera lacei Craib
Indigofera langebergensis L.Bolus
Indigofera laxiracemosa Baker f.
Indigofera leprieurii Baker f. | Indigofera | Wikipedia | 489 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera longiracemosa Baill.
Indigofera lyallii Baker
subsp. lyallii Baker
subsp. nyassica J.B.Gillett
Indigofera longibarbata Engl.
Indigofera longimucronata Baker f.
Indigofera macrophylla Schum. & Thonn.
Indigofera mangokyensis "R.Vig., p.p.A"
Indigofera melanadenia Harv.
Indigofera natalensis Bolus
Indigofera nigrescens King & Prain
Indigofera pendula Franch.
var. pendula Franch.
var. umbrosa (Craib) Y.Y.Fang & C.Z.Zheng
Indigofera platycarpa Rose
Indigofera podocarpa Baker f. & Martin
Indigofera pratensis F.Muell.
Indigofera rhynchocarpa Baker
var. latipinna (Johnson) J.B.Gillett
var. rhynchocarpa Baker
var. uluguruensis J.B.Gillett
Indigofera roseocaerulea Baker f.
Indigofera rugosa Benth.
Indigofera sanguinea N.E.Br.
Indigofera schlechteri Baker f.
Indigofera sedgewickiana Vatke
Indigofera setiflora Baker
Indigofera sokotrana Vierh.
Indigofera sootepensis Craib
Indigofera stenophylla Guill. & Perr.
Indigofera subcorymbosa Baker
Indigofera suffruticosa Mill.—anil indigo, anil de pasto
Indigofera sutherlandoides Baker
Indigofera swaziensis Bolus
subsp. perplexa (N.E.Br.) J.B.Gillett
subsp. swaziensis Bolus | Indigofera | Wikipedia | 370 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera thibaudiana DC.
Indigofera tinctoria L.—indigo, true indigo, dye indigo
subsp. arcuata (J.B.Gillett) Schrire
subsp. tinctoria L.
Indigofera tristis E.Mey.
Indigofera truxillensis Kunth
Indigofera varia E.Mey.
Indigofera venulosa Benth.
Indigofera verrucosa Eckl. & Zeyh.
Indigofera verruculosa Peter G.Wilson
Indigofera vicioides Jaub. & Spach
var. rogersii R.E.Fr.
var. vicioides Jaub. & Spach
Indigofera zeyheri Eckl. & Zeyh.
Indigofera zollingeriana Miq.—Zollinger's indigo
Cape clade
Indigofera alopecuroides (Burm.f.) DC.
Indigofera alpina Eckl. & Zeyh.
Indigofera amoena Aiton
Indigofera angustata E.Mey.
Indigofera angustifolia L.
var. angustifolia L.
var. tenuifolia (Lam.) Harv.
Indigofera brachystachya (DC.) E.Mey.
Indigofera burchellii DC.
Indigofera candolleana Meissner
Indigofera capillaris Thunb. | Indigofera | Wikipedia | 287 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera concava Harv.
Indigofera cuneifolia Eckl. & Zeyh.
Indigofera cytisoides Thunb.
Indigofera declinata E.Mey.
Indigofera denudata Thunb.
Indigofera digitata Thunb.
Indigofera dimidiata Walp.
Indigofera filicaulis Eckl. & Zeyh.
Indigofera filifolia Thunb.
Indigofera flabellata Harv.
Indigofera gifbergensis C.H.Stirt. & Jarvie
Indigofera glomerata E.Mey.
Indigofera heterophylla Thunb.
Indigofera hispida Eckl. & Zeyh.
Indigofera ionii Jarvie & C.H.Stirt.
Indigofera mauritanica (L.) Thunb.
Indigofera merxmuelleri A.Schreib.
Indigofera meyeriana Eckl. & Zeyh.
Indigofera mollis Eckl. & Zeyh.
Indigofera nigromontana Eckl. & Zeyh.
Indigofera nudicaulis E.Mey.
Indigofera ovata Thunb.
Indigofera porrecta Eckl. & Zeyh.
Indigofera psoraloides (L.) L.
Indigofera sarmentosa L.f.
Indigofera sulcata DC.
Indigofera superba C.H.Stirt.
Tethyan clade
Indigofera achyranthoides Taub.
Indigofera alternans DC.
Indigofera ammoxylum (DC.) Polhill
Indigofera anabibensis A.Schreib.
Indigofera angulosa Edgew.
Indigofera antunesiana Harms
Indigofera arabica Jaub. & Spach
Indigofera aspera DC.
Indigofera asperifolia Benth.
var. asperifolia Benth.
var. lanceolata Chodat & Hassler
var. macrophylla Chodat & Hassler
Indigofera auricoma E.Mey. | Indigofera | Wikipedia | 433 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera bemarahaensis Du Puy & Labat
Indigofera bongardiana (Kuntze) Burkart
Indigofera bongensis Kotschy & Peyr.
Indigofera cerighellii M.Pelt.
Indigofera cloiselii Drake
Indigofera conjugata Baker
var. conjugata Baker
var. schweinfurthii (Taub.) J.B. Gillett
var. trimorphophylla (Taub.) J.B. Gillett
Indigofera cordifolia Roth
Indigofera daleoides Harv.
Indigofera dalzellii T.Cooke
Indigofera depauperata Drake
Indigofera depressa Harv.
Indigofera dionaeifolia (S. Moore) Schrire
Indigofera diphylla Vent.
Indigofera disticha Eckl. & Zeyh.
Indigofera diversifolia DC.
Indigofera drepanocarpa Taub. | Indigofera | Wikipedia | 194 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera ewartiana Domin
Indigofera exellii Torre
Indigofera fanshawei J.B.Gillett
Indigofera glandulosa Wendl.
var. glandulosa Wendl.
var. sykesii Baker
Indigofera glaucescens Eckl. & Zeyh.
Indigofera guaranitica Hassl.
Indigofera gypsacea Thulin
Indigofera hartwegii Rydb.
Indigofera hiranensis Thulin
Indigofera hochstetteri Baker
subsp. hochstetteri Baker
subsp. streyana (Merxm.) A.Schreib.
Indigofera hololeuca Harv.
Indigofera humbertiana M.Pelt.
Indigofera interrupta (Du Puy, Labat & Schrire) Schrire
Indigofera jamaicensis Spreng.
Indigofera kelleri Baker f.
Indigofera leptocarpa Eckl. & Zeyh.
Indigofera leptosepala Nutt.
Indigofera lespedezioides Kunth
var. acutifolia Hassler
var. lespedezioides Kunth
Indigofera leucoclada Baker
Indigofera linifolia (L.f.) Retz.
Indigofera linnaei Ali
Indigofera longidentata (Du Puy, Labat & Schrire) Schrire
Indigofera lupatana Baker f.
Indigofera mahafalensis (Du Puy, Labat & Schrire) Schrire
Indigofera marmorata Balf.f.
Indigofera microcarpa Desv.
Indigofera miniata Ortega—coastal indigo, scarlet-pea
Indigofera nephrocarpa Balf.f.
Indigofera nephrocarpoides J.B.Gillett
Indigofera nummularia Baker
Indigofera obcordata Eckl. & Zeyh.
Indigofera oblongifolia Forssk.
Indigofera praticola Baker f.
Indigofera pseudocompressa (Du Puy, Labat & Schrire) Schrire
Indigofera pungens E.Mey. | Indigofera | Wikipedia | 434 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera schimperi Jaub. & Spach
Indigofera semitrijuga Forssk.
Indigofera sessiliflora DC.
Indigofera spicata Forssk.
Indigofera spiniflora Boiss.
Indigofera spinosa Forssk.
Indigofera squalida Prain
Indigofera subulata Vahl ex Poir.
Indigofera tephrosioides Kunth
Indigofera thomsonii Baker f.
Indigofera torulosa E.Mey.
var. angustiloba (Baker f.) J.B.Gillett
var. torulosa E.Mey.
Indigofera trifoliata L.—threeleaf indigo
var. duthiei (Naik) Sanjappa
var. trifoliata L.
var. unifoliolata (Merr.) De Kort & G.Thijsse
Indigofera trigonelloides Jaub. & Spach
Indigofera trita L.f.—Asian indigo
var. maffei (Chiov.) Ali
var. marginulata (Wight & Arn.) Sanjappa
var. scabra (Roth) De Kort & G.Thijsse
var. trita L.f.
Indigofera volkensii Taub.
Unassigned
Indigofera acanthinocarpa Blatt.
Indigofera acanthoclada Dinter
Indigofera accepta N.E.Br.
Indigofera acutiflora N.E.Br.
Indigofera acutipetala Y.Y.Fang & C.Z.Zheng
Indigofera adenocarpa E.Mey.
Indigofera adenoides Baker f.
Indigofera adesmiifolia A.Gray
Indigofera ambelacensis Schweinf.
Indigofera amitina N.E.Br.
Indigofera ammobia Maconochie
Indigofera ancistrocarpa Thulin
Indigofera andrewsiana J.B.Gillett
Indigofera andringitrensis R.Vig.
Indigofera ankaratrensis R.Vig.
Indigofera aquae-nitentis Bremek.
Indigofera aralensis Gagnep.
Indigofera arenophila Schinz
Indigofera argutidens Craib | Indigofera | Wikipedia | 459 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera aristata Spreng.
Indigofera arnottii (Kuntze) Peter G. Wilson
Indigofera aspalathoides DC.
Indigofera asterocalycina Gilli
Indigofera atrata N.E.Br.
Indigofera atricephala J.B.Gillett
Indigofera baileyi F.Muell.
Indigofera balfouriana Craib
Indigofera bancroftii Peter G.Wilson
Indigofera bangweolensis R.E.Fr.
Indigofera banii N.D.Khoi & Yakovlev
Indigofera barteri Hutch. & Dalziel
Indigofera basedowii E.Pritz.
subsp. basedowii E.Pritz.
subsp. longibractea (J.Black) Peter G.Wilson
Indigofera bayensis Thulin
Indigofera bella Prain
Indigofera benguellensis Baker
Indigofera berhautiana J.B.Gillett
Indigofera bijuga Walp.
Indigofera blaiseae Du Puy & Labat
Indigofera bogdanii J.B.Gillett
Indigofera boinensis R.Vig.
Indigofera brachynema J.B.Gillett
Indigofera bracteata Baker
Indigofera brassii Baker
Indigofera brevidens Benth.
var. brevidens Benth.
var. uncinata Benth.
Indigofera brevifilamenta J.B.Gillett
Indigofera breviracemosa Torre
Indigofera breviviscosa J.B.Gillett
Indigofera brunoniana Wall.
Indigofera buchananii Burtt Davy
Indigofera bungeana Walp. | Indigofera | Wikipedia | 339 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera burttii Baker f.
Indigofera bussei J.B.Gillett
Indigofera calcicola Craib
Indigofera campestris Benth.
var. angustifolia M.Micheli
var. campestris Benth.
var. intermedia Hassler
Indigofera candicans Aiton
Indigofera capitata Kotschy
Indigofera carlesi Craib
Indigofera caudata Dunn
Indigofera cecilii N.E.Br.
Indigofera cedrorum Dunn
Indigofera chaetodonta Franch.
Indigofera charlierana Schinz
var. charlierana Schinz
var. lata J.B.Gillett
var. scaberrima (Schinz) J.B.Gillett
Indigofera chenii S.S.Chien
Indigofera chevalieri Tisser.
Indigofera chirensis J.B.Gillett
Indigofera chuniana F.P.Metcalf
Indigofera ciferrii Chiov.
Indigofera cinerascens Franch.
Indigofera circinella Baker f.
Indigofera circinnata Harv.
Indigofera cliffordiana J.B.Gillett
Indigofera commixta N.E.Br.
Indigofera comosa N.E.Br.
Indigofera complanata Spreng.
Indigofera complicata Eckl. & Zeyh.
Indigofera concinna Baker
Indigofera conferta J.B.Gillett
Indigofera confusa Prain & Baker f.
Indigofera congolensis De Wild. & T.Durand
var. bongensis (Baker f.) J.B. Gillett
var. congolensis De Wild. & T.Durand
Indigofera constricta (Thwaites) Trimen
var. constricta (Thwaites) Trimen
var. deorum McVaugh
Indigofera corallinosperma Torre
Indigofera coronillifolia Benth.
Indigofera costaricensis Benth. | Indigofera | Wikipedia | 410 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera crebra N.E.Br.
Indigofera crotalarioides (Klotzsch) Baker
Indigofera cryptantha Harv.
subsp. cryptantha Harv.
subsp. desmodioides (Baker) Du Puy & Labat
Indigofera cuitoensis Baker f.
Indigofera cuneata Oliv.
Indigofera cunenensis Torre
Indigofera curvata J.B.Gillett
Indigofera curvirostrata Thulin
Indigofera cylindrica sensu auct.
Indigofera damarana Merxm. & A.Schreib.
Indigofera daochengensis Y.Y.Fang & C.Z.Zheng
Indigofera dasyantha Baker f.
Indigofera dasycephala Baker f.
Indigofera dauensis J.B.Gillett
Indigofera deccanensis Sanjappa
Indigofera deflersii Baker f.
Indigofera dekindtii Tisser.
Indigofera delagoaensis J.B.Gillett
Indigofera delavayi Franch.
Indigofera dembianensis (Chiov.) J.B.Gillett
Indigofera densa N.E.Br.
Indigofera densiflora M.Martens & Galeotti
Indigofera densifructa Y.Y.Fang & C.Z.Zheng
Indigofera desertorum Torre
Indigofera dichroa Craib
Indigofera dillwynioides Harv.
Indigofera discolor Rydb.
Indigofera dissitiflora Oliv.
Indigofera dolichochaete Craib
Indigofera dolichothyrsa Baker f.
Indigofera dregeana E.Mey.
Indigofera dumetorum Craib
Indigofera dyeri Britten | Indigofera | Wikipedia | 357 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera efoliata F.Muell.
Indigofera egens N.E.Br.
Indigofera elandsbergensis Phillipson
Indigofera elliotii (Baker f.) J.B.Gillett
Indigofera elwakensis J.B.Gillett
Indigofera emarginata Y.Y.Fang & C.Z.Zheng
Indigofera emarginelloides J.B.Gillett
Indigofera emmae De Kort & G.Thijsse
Indigofera enormis N.E.Br.
Indigofera erecta Thunb.
Indigofera eriocarpa E.Mey.
Indigofera esquirolii H.Lev.
Indigofera evansiana Burtt Davy
Indigofera evansii Schltr.
Indigofera exigua Eckl. & Zeyh.
Indigofera exilis Grierson & D.G.Long
Indigofera eylesiana J.B.Gillett
Indigofera faulknerae J.B.Gillett
Indigofera filiformis L.f.
Indigofera filipes Harv.
Indigofera flavicans Baker
Indigofera floribunda N.E.Br.
Indigofera foliosa E.Mey.
Indigofera forrestii Craib
Indigofera fortunei Craib
Indigofera fruticosa Rose
Indigofera fulcrata Harv.
Indigofera fulvopilosa Brenan
Indigofera fuscosetosa Baker
Indigofera galpinii N.E.Br.
Indigofera gangetica Sanjappa
Indigofera garckeana Vatke
Indigofera geminata Baker
Indigofera giessii A.Schreib.
Indigofera glaucifolia Cronquist
Indigofera gloriosa Cronquist
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Indigofera gracilis Spreng.
Indigofera graniticola J.B.Gillett
Indigofera griseoides Harms
Indigofera grisophylla Fourc.
Indigofera guatemalensis Moc., Sessé & Cerv. ex Backer
Indigofera guthriei Bolus
Indigofera hamiltonii Duthie & Prain
Indigofera hamulosa Schltr.
Indigofera hancockii Craib
Indigofera hantamensis Diels
Indigofera helmsii Peter G.Wilson
Indigofera hendecaphylla Jacq.—trailing indigo, creeping indigo, spicate indigo
var. hendecaphylla Jacq.
var. siamensis (Hosseus) Gagnep.
Indigofera henryi Craib
Indigofera heterocarpa Baker
Indigofera hewittii Baker f.
Indigofera hinanensis H.T.Tsai & T.F.Yu
Indigofera hofmanniana Schinz
Indigofera holstii (Baker f.) Baker f.
Indigofera holubii N.E.Br.
Indigofera howellii Craib & W.W.Sm.
Indigofera huillensis Baker f.
Indigofera humifusa Eckl. & Zeyh.
Indigofera humilis Kunth
Indigofera hundtii Rossberg
Indigofera hybrida N.E.Br.
Indigofera hygrobia Malme
Indigofera imerinensis Du Puy & Labat
Indigofera incana Thunb.
Indigofera incompta McVaugh | Indigofera | Wikipedia | 316 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera ingrata N.E.Br.
Indigofera insularis Chiov.
Indigofera intermedia Harv.
Indigofera intricata Boiss.
Indigofera inyangana N.E.Br.
Indigofera irodoensis Du Puy & Labat
Indigofera ischnoclada Harms
Indigofera itremoensis Du Puy & Labat
Indigofera jaliscensis Rose
Indigofera jikongensis Y.Y.Fang & C.Z.Zheng
Indigofera jindongensis Y.Y.Fang & C.Z.Zheng
Indigofera karkarensis (Thulin) Schrire
Indigofera kasinii Boonyam.
Indigofera kerrii De Kort & G.Thijsse
Indigofera kerstingii Harms
Indigofera knoblecheri Kotschy
Indigofera kongwaensis J.B.Gillett
Indigofera krookii Zahlbr.
Indigofera kuntzei Harms
Indigofera kurtzii Kuntze
Indigofera lamellata Thulin
Indigofera lancifolia Rydb.
Indigofera lasiantha Desv.
Indigofera latifolia Micheli
Indigofera latisepala J.B.Gillett
Indigofera laxiflora Craib
Indigofera leendertziae N.E.Br.
Indigofera lenticellata Craib
Indigofera lepida N.E.Br.
Indigofera leptoclada Harms
Indigofera letestui Tisser.
Indigofera leucotricha E.Pritz.
Indigofera limosa L.Bolus
Indigofera lindheimeriana Scheele—Lindheimer's indigo
Indigofera litoralis Chun & T.Chen
Indigofera livingstoniana J.B.Gillett
Indigofera longicauda Thuan
Indigofera longipedicellata J.B.Gillett
Indigofera longipedunculata Y.Y.Fang & C.Z.Zheng
Indigofera longistaminata Schrire
Indigofera lotononoides Baker f.
Indigofera lughensis Thulin
Indigofera luzonensis De Kort & G.Thijsse
Indigofera lydenburgensis N.E.Br. | Indigofera | Wikipedia | 448 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera macrantha Harms
Indigofera madagascariensis Vatke
Indigofera malacostachys Harv.
Indigofera malindiensis J.B.Gillett
Indigofera malongensis Cronquist
Indigofera manyoniensis Baker f.
Indigofera maritima Baker
Indigofera masaiensis J.B.Gillett
Indigofera masonae N.E.Br.
Indigofera matudae Lundell
Indigofera maymyoensis Sanjappa
Indigofera megacephala J.B.Gillett
Indigofera mekongensis Jessup
Indigofera mendesii Torre
Indigofera mendoncae J.B.Gillett
Indigofera mengtzeana Craib
Indigofera micheliana Rose
Indigofera micrantha E.Mey.
Indigofera micropetala Baker f.
Indigofera mildrediana Torre
Indigofera milne-redheadii J.B.Gillett
Indigofera minbuensis Gage
Indigofera mischocarpa Schltr.
Indigofera mollicoma N.E.Br.
Indigofera monanthoides J.B.Gillett
Indigofera monbeigii Craib
Indigofera monophylla DC.
Indigofera monostachya Eckl. & Zeyh.
Indigofera montana Rose
Indigofera mouroundavensis Baill.
Indigofera muliensis Y.Y.Fang & C.Z.Zheng
Indigofera mundtiana Eckl. & Zeyh.
Indigofera mupensis Torre
subsp. abercornensis J.B.Gillett
subsp. mupensis Torre
Indigofera mwanzae J.B.Gillett
Indigofera myosurus Craib
Indigofera nairobiensis Baker f.
subsp. nairobiensis Baker f.
subsp. viscida J.B.Gillett
Indigofera nambalensis Harms | Indigofera | Wikipedia | 369 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera neoglabra Wang & T.Tang
Indigofera neosericopetala P.C. Li
Indigofera nesophila Lievens & Urbatsch
Indigofera nigricans Pers.
Indigofera nivea R.Vig.
Indigofera nugalensis Thulin
Indigofera nummulariifolia (L.) Alston
Indigofera obscura N.E.Br.
Indigofera ogadensis J.B.Gillett
Indigofera oligophylla Klotzsch
Indigofera omariana J.B.Gillett
Indigofera ormocarpoides Baker
Indigofera orthocarpa C.Presl
Indigofera oubanguiensis Tisser.
Indigofera ovina Harv.
Indigofera oxalidea Baker
Indigofera oxytropis Harv.
Indigofera oxytropoides Schltr.
Indigofera palmeri S.Watson
Indigofera pampaniniana Craib
Indigofera panamensis Rydb.
Indigofera pappei Fourc.
Indigofera paracapitata J.B.Gillett
Indigofera paraglaucifolia Torre
Indigofera paraoxalidea Torre
Indigofera parkesii Craib
Indigofera parodiana Burkart
Indigofera parviflora F. Heyne ex Hook. & Arn.
Indigofera patula Baker
Indigofera pauciflora Eckl. & Zeyh.
Indigofera paucifolioides Blatt. & Hallb.
Indigofera paucistrigosa J.B.Gillett | Indigofera | Wikipedia | 320 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera pearsonii Baker f.
Indigofera pechuelii Kuntze
Indigofera pedicellata Wight & Arn.
Indigofera pedunculata Baker
Indigofera pellucida J.B.Gillett & Thulin
Indigofera peltata J.B.Gillett
Indigofera peltieri Du Puy & Labat
Indigofera penduloides Y.Y.Fang & C.Z.Zheng
Indigofera perriniana Spreng.
Indigofera petiolata Cronquist
Indigofera phyllanthoides Baker
Indigofera pilgeriana Schltr.
Indigofera pilosa Poir.—softhairy indigo
Indigofera pinifolia Baker
Indigofera placida N.E.Br.
Indigofera platypoda E.Mey.
Indigofera pobeguinii J.B.Gillett
Indigofera polygaloides M.B.Scott
Indigofera polysphaera Baker
Indigofera pongolana N.E.Br.
Indigofera porrigens Colla
Indigofera prieureana Guill. & Perr.
Indigofera procumbens L.
Indigofera prostrata Willd.
Indigofera pruinosa Baker
Indigofera pseudoevansii Hilliard & B.L.Burtt
Indigofera pseudointricata J.B.Gillett
Indigofera pseudoparvula R.Vig.
Indigofera pseudoreticulata Grierson & D.G.Long
Indigofera pseudosubulata Baker f.
Indigofera pseudotinctoria Matsum.
Indigofera pueblensis Rydb.
Indigofera purpusii Brandegee
Indigofera quinquefolia E.Mey.
Indigofera radicifera Cronquist
Indigofera ramosissima J.B.Gillett
Indigofera ramulosissima Hosok.
Indigofera rautanenii Baker f.
Indigofera reducta N.E.Br.
Indigofera rehmannii Baker f.
Indigofera remota Baker f.
Indigofera repens Cronquist
Indigofera reticulata Franch.
Indigofera retusa N.E.Br.
Indigofera rhodantha Fourc.
Indigofera rhytidocarpa Harv.
subsp. angolensis J.B.Gillett
subsp. rhytidocarpa Harv. | Indigofera | Wikipedia | 482 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera rigioclada Craib
Indigofera ripae N.E.Br.
Indigofera rojasii Hassl.
Indigofera rostrata Bolus
Indigofera ruspolii Baker f.
Indigofera sabulosa Thulin
Indigofera salmoniflora Rose
Indigofera salteri Baker f.
Indigofera santapaui Sanjappa
Indigofera santosii Torre
Indigofera saxicola Benth.
Indigofera scabrida Dunn
Indigofera scarciesii Scott-Elliot
Indigofera schinzii N.E.Br.
Indigofera schliebenii Harms
Indigofera schultziana F.Muell.
Indigofera scopiformis Thulin
Indigofera sebungweensis J.B.Gillett
Indigofera secundiflora Poir.
Indigofera senegalensis Lam.
Indigofera sensitiva Franch.
Indigofera sericovexilla C.T.White
Indigofera sesquipedalis Sanjappa
Indigofera sessilifolia DC.
Indigofera setosa N.E.Br.
Indigofera sieberiana Scheele
Indigofera silvestrii Pamp.
var. alii Sanjappa
var. silvestrii Pamp.
Indigofera simaoensis Y.Y.Fang & C.Z.Zheng
Indigofera sisalis J.B.Gillett
Indigofera smutsii J.B.Gillett
Indigofera sordida Harv.
Indigofera souliei Craib
Indigofera sparsa Baker
Indigofera sparteola Chiov.
Indigofera sphaerocarpa A.Gray—Sonoran indigo
Indigofera sphinctosperma Standl.
Indigofera splendens Ficalho & Hiern
Indigofera stachyodes Lindl.
Indigofera stenosepala Baker
Indigofera sticta Craib
Indigofera stricta L.f.
Indigofera strigulosa Baker f.
Indigofera suarezensis Du Puy & Labat
Indigofera subargentea De Wild.
Indigofera subsecunda Gagnep.
Indigofera subulifera Baker
Indigofera subverticellata Gagnep.
Indigofera szechuensis Craib
Indigofera taborensis J.B.Gillett
Indigofera tanaensis J.B.Gillett
Indigofera taruffiana Torre
Indigofera taylori J.B.Gillett
Indigofera teixeirae Torre | Indigofera | Wikipedia | 494 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera tengyuehensis H.T.Tsai & T.F.Yu
Indigofera tenuifolia Lam.
Indigofera tenuipes Polhill
Indigofera tenuis Milne-Redh.
subsp. major J.B.Gillett
subsp. tenuis Milne-Redh.
Indigofera tenuissima E.Mey.
Indigofera terminalis Baker
Indigofera tetraptera Taub.
Indigofera texana Buckley
Indigofera thesioides Jarvie & C.H.Stirt. | Indigofera | Wikipedia | 105 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera thikaensis J.B.Gillett
Indigofera thothathri Sanjappa
Indigofera thymoides Baker
Indigofera tirunelvelica Sanjappa
Indigofera tomentosa Eckl. & Zeyh.
Indigofera torrei J.B.Gillett
Indigofera transvaalensis Baker f.
Indigofera trialata A.Chev.
Indigofera trichopoda Guill. & Perr.
Indigofera trifolioides Baker f.
Indigofera triquetra E.Mey.
Indigofera tristoides N.E.Br.
Indigofera tryonii Domin
Indigofera tumidula Rose
Indigofera ufipaensis J.B.Gillett
Indigofera ugandensis Baker f.
Indigofera vanderystii J.B.Gillett
Indigofera velutina E.Mey.
Indigofera venusta Eckl. & Zeyh.
Indigofera viscidissima Baker
subsp. orientalis J.B.Gillett
subsp. viscidissima Baker
Indigofera vivax Schrank
Indigofera wildiana J.B.Gillett
Indigofera williamsonii (Harv.) N.E.Br.
Indigofera wilsonii Craib
Indigofera woodii Bolus
Indigofera zanzibarica J.B.Gillett
Indigofera zavattarii Chiov.
Indigofera zenkeri Baker f.
Indigofera zornioides Du Puy & Labat
Species names with uncertain taxonomic status
The status of the following species is unresolved:
Indigofera abyssinica Hochst. ex Baker
Indigofera adaochengensis Y.Y. Fang & C.Z. Zheng
Indigofera adenophylla Graham
Indigofera adenotricha Peter G.Wilson
Indigofera adesmiaefolia A. Gray
Indigofera adonensis E.Mey.
Indigofera aeruginis Schweinf.
Indigofera agowensis Hochst. ex Baker
Indigofera alata Schweinf.
Indigofera alba Gouault
Indigofera amaliae Domin
Indigofera angulata Lindl.
Indigofera angulata Rottler ex Spreng.
Indigofera aphylla Breiter
Indigofera arborescens Zuccagni | Indigofera | Wikipedia | 465 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera arghawan Royle
Indigofera argyrea Chiov.
Indigofera armata Wall.
Indigofera ascendens Walp.
Indigofera astragaloides Welw. ex Romariz
Indigofera athrophylla Eckl. & Zeyh.
Indigofera axillaris E.Mey.
Indigofera bagshawei Baker f.
Indigofera baoulensis A.Chev.
Indigofera barbata Desv.
Indigofera barcensis Chiov.
Indigofera bequaerti De Wild.
Indigofera berteroana Spreng.
Indigofera bertolonii Steud.
Indigofera biflora Roth
Indigofera bilabiata Loisel. ex Drapiez
Indigofera boylei Hort. ex Vilmorin's
Indigofera brachycarpa Graham
Indigofera brachyodon Domin
Indigofera brachyphylla Al-Turki
Indigofera brachypoda Steud. ex A.Rich.
Indigofera brevipes (S. Watson) Rydb.
Indigofera bufalina Lour.
Indigofera caesia Zipp. ex Span.
Indigofera caespitosa Wight
Indigofera calva E.Mey.
Indigofera carlesii Craib
Indigofera ceciliae N.E.Br. | Indigofera | Wikipedia | 266 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera celebica Miq.
Indigofera centrota Eckl. & Zeyh.
Indigofera chitralensis Sanjappa
Indigofera cinericolor F.Muell.
Indigofera clitorioides G.Don
Indigofera colorata Roxb. ex Wight & Arn.
Indigofera coluteifolia Jaub. & Spach
Indigofera condensata De Wild.
Indigofera conradsii Baker f.
Indigofera constricta Rydb.
Indigofera cornezuelo Moc. & Sessé ex DC.
Indigofera cornuligera Peter G.Wilson & Rowe
Indigofera coronillaefolia A. Cunn. ex Benth.
Indigofera coronillaefolia hort.
Indigofera crassisiliqua Steud.
Indigofera dalzelliana (Kuntze) Peter G.Wilson
Indigofera dalzielii Hutch.
Indigofera debilis Graham
Indigofera decumbens Hill
Indigofera deginensis Sanjappa
Indigofera dequinensis Sanjappa
Indigofera dewevrei Micheli
Indigofera diffusa Desv.
Indigofera dimorphophylla Schinz
Indigofera disjuncta J. B. Gillett
Indigofera dodecaphylla Ficalho & Hiern
Indigofera dorycnium Fenzl
Indigofera dosycnium Fenzl
Indigofera dubia Steud.
Indigofera dumosa E.Mey.
Indigofera elachantha Peter G.Wilson & Rowe
Indigofera elatior Carrière
Indigofera elegans Schumach. & Thonn.
Indigofera ellenbeckii Baker f.
Indigofera elskensii Baker f.
Indigofera enonensis E.Mey.
Indigofera erectifructa Y.Endo, H.Ohashi & Madulid
Indigofera erythrantha Hochst. ex Baker
Indigofera erythrogrammoides De Wild.
Indigofera esquirolii H. Lév.
Indigofera faberi Craib
Indigofera flavovirens R.E.Fr.
Indigofera flexuosa Eckl. & Zeyh.
Indigofera flexuosa Graham
Indigofera florida E.Mey.
Indigofera foliolosa Graham
Indigofera formosana Matsum.
Indigofera franchetii X.F.Gao & Schrire
Indigofera frumentacea Roxb. ex Wight & Arn. | Indigofera | Wikipedia | 505 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera fruticulosa Walp.
Indigofera fuzi Sieb. ex Miq.
Indigofera gilletii De Wild. & T.Durand
Indigofera glauca Lam.
Indigofera glauca Perr. ex DC.
Indigofera grahamiana Steud.
Indigofera grandifoliola Carrière
Indigofera graveolens Schrad.
Indigofera griquana Schltr. ex Zahlbr.
Indigofera guineensis Schumach. & Thonn.
Indigofera haematica Peter G.Wilson
Indigofera hainanensis H.T.Tsai & T.T.Yü
Indigofera heptaphylla Hiern
Indigofera hislopii Baker f.
Indigofera hockii De Wild. & Baker f.
Indigofera hookeriana Meisn.
Indigofera hover Forssk.
Indigofera inconspicua Domin
Indigofera iwafusi Sieb. ex Lavallee
Indigofera jaubertiana Schweinf.
Indigofera jirahulia Buch.-Ham.
Indigofera juncea Decne.
Indigofera karongensis Baker
Indigofera kerensis Chiov.
Indigofera kisantuensis De Wild. & T.Durand
Indigofera kotoensis Hayata
Indigofera latibracteata Harms
Indigofera latipinna I.M.Johnst.
Indigofera laxeracemosa Baker f.
Indigofera leptocaulis Eckl. & Zeyh.
Indigofera leptophylla E.Mey.
Indigofera lignosa De Wild.
Indigofera limifolia Benth.
Indigofera lindleyana Spreng. ex Steud.
Indigofera linearis DC.
Indigofera linearis Guill. & Perr.
Indigofera litoralis Chun & T.C. Chen
Indigofera liukiuennsis Makino & Nemoto
Indigofera lonchocarpifolia Baker
Indigofera longebarbata Engl.
Indigofera longepedicellata J. B. Gillett
Indigofera longeracemosa Boivin ex Baill.
Indigofera longibractea J.M.Black
Indigofera lupulina Baker
Indigofera machaerocarpa Fenzl ex Baker
Indigofera macroptera hort. ex Lavallée
Indigofera macrostachys Vent.
Indigofera mangokyensis R. Vig.
Indigofera marginata Walp.
Indigofera masukuensis Baker | Indigofera | Wikipedia | 507 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera mckinlayi F.Muell.
Indigofera mearnsi Standl.
Indigofera megaphylla X.F.Gao
Indigofera melanotricha Steud. ex A.Rich.
Indigofera melolobioides Benth. ex Harv.
Indigofera microphylla Lam.
Indigofera microstachya C.Presl
Indigofera minutiflora Hochst. ex Chiov.
Indigofera minutiflora Walp.
Indigofera moeroensis De Wild.
Indigofera multijuga Baker
Indigofera mutisii (Kunth) Spreng.
Indigofera nematopoda Baker f.
Indigofera neoarborea Hu ex F.T. Wang & Tang
Indigofera noldeae Rossbach
Indigofera nuda G.Don
Indigofera nyikensis Baker
Indigofera oligantha Harms ex Baker f.
Indigofera oligosperma DC.
Indigofera orixensis Roxb. ex Wight & Arn.
Indigofera oroboides E.Mey.
Indigofera oxyrachis Peter G.Wilson
Indigofera paludosa Lepr. ex Guill. & Perr.
Indigofera palustris Vatke
Indigofera perrottetii DC.
Indigofera petraea Peter G.Wilson & Rowe
Indigofera pilifera Peter G.Wilson & Rowe
Indigofera platyspira J.B.Gillett ex Thulin & M.G.Gilbert
Indigofera plumosa Spreng.
Indigofera polyclada Peter G.Wilson & Rowe
Indigofera polysperma De Wild. & T.Durand
Indigofera pratensis var. coriacea Domin
Indigofera preladoi Harms
Indigofera pretoriana Harms
Indigofera procumbens Torre
Indigofera propinqua Hochst. ex Chiov.
Indigofera psammophila Peter G.Wilson
Indigofera pseudoheterantha X.F.Gao & Schrire
Indigofera pseudomoniliformis Schrire
Indigofera purpurea Page ex Steud.
Indigofera quadrangularis Graham
Indigofera racemosa L.
Indigofera rarifolia Steud.
Indigofera rechodes Eckl. & Zeyh.
Indigofera reflexa E.Mey.
Indigofera rhechodes Walp.
Indigofera rhodosantha Zipp. ex Miq.
Indigofera rigescens E.Mey.
Indigofera roylei Koehne | Indigofera | Wikipedia | 505 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera roylii Hort. ex Dippel
Indigofera rubromarginata Thulin
Indigofera rumphiensis Schrire
Indigofera rupestris Eckl. & Zeyh.
Indigofera rupicola Peter G.Wilson & Rowe
Indigofera sabulicola Benth.
Indigofera saltiana Steud.
Indigofera sangana Harms, in Schltr.
Indigofera scabrella Kazandj. & Peter G.Wilson
Indigofera schimperiana Hochst.
Indigofera scoparia Vahl ex DC.
Indigofera secunda E.Mey.
Indigofera sericea Benth. ex Baker
Indigofera sericea L.
Indigofera sericea Thunb. ex Harv.
Indigofera sericophylla Franch.
Indigofera setacea E.Mey.
Indigofera shipingensis X.F.Gao
Indigofera shirensis Taub. ex Baker f.
Indigofera signata Domin
Indigofera similis N.E.Br.
Indigofera sinuspersica Mozaff.
Indigofera socotrana Vierh.
Indigofera sofa Scott-Elliot
Indigofera solirimae Schrire
Indigofera somalensis Vatke
Indigofera sousae M.A.Exell
Indigofera sparsiflora Hochst. ex Baker
Indigofera speciosa Fraser ex Hook.
Indigofera spirocarpa Harms
Indigofera spoliata Hoffmanns.
Indigofera subincana N.E.Br.
Indigofera subquadriflora Hochst. ex Chiov.
Indigofera subtilis E.Mey.
Indigofera sylvatica Sieber ex Spreng.
Indigofera sylvestris Pamp.
Indigofera taiwaniana T.C.Huang & M.J.Wu
Indigofera tenella Schumach. & Thonn.
Indigofera tenella Vahl ex DC.
Indigofera tenuicaulis Klotzsch
Indigofera tenuisiliqua Schweinf.
Indigofera ternata Roxb. ex Wight & Arn.
Indigofera thirionni H.Lév.
Indigofera thonningii Schumach. & Thonn.
Indigofera tinctaria Hook.
Indigofera triflora Peter G.Wilson & Rowe
Indigofera trita var. nubica (J.B.Gillett) L.Boulos & Schrire
Indigofera tritoidea Baker | Indigofera | Wikipedia | 508 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Indigofera ultima (Kuntze) Peter G.Wilson
Indigofera unifoliata Merr.
Indigofera urostachya Fenzl ex Baker
Indigofera viguieri Callm. & Labat
Indigofera villosa Berg. ex Walp.
Indigofera wannanii Peter G.Wilson
Indigofera wentzeliana Harms
Indigofera wynbergensis S.Moore
Indigofera zig-zag De Wild. | Indigofera | Wikipedia | 89 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Ecology
Indigofera species are used as food plants by the larvae of some Lepidoptera species, including the turnip moth (Agrotis segetum). | Indigofera | Wikipedia | 33 | 2142673 | https://en.wikipedia.org/wiki/Indigofera | Biology and health sciences | Fabales | Plants |
Rhinorrhea (American English), also spelled rhinorrhoea or rhinorrhœa (British English), or informally runny nose is the free discharge of a thin mucus fluid from the nose; it is a common condition. It is a common symptom of allergies (hay fever) or certain viral infections, such as the common cold or COVID-19. It can be a side effect of crying, exposure to cold temperatures, cocaine abuse, or drug withdrawal, such as from methadone or other opioids. Treatment for rhinorrhea may be aimed at reducing symptoms or treating underlying causes. Rhinorrhea usually resolves without intervention, but may require treatment by a doctor if symptoms last more than 10 days or if symptoms are the result of foreign bodies in the nose.
The term rhinorrhea was coined in 1866 from the Greek rhino- ("of the nose") and -rhoia ("discharge" or "flow").
Signs and symptoms
Rhinorrhea is characterized by an excess amount of mucus produced by the mucous membranes that line the nasal cavities. The membranes create mucus faster than it can be processed, causing a backup of mucus in the nasal cavities. As the cavity fills up, it blocks off the air passageway, causing difficulty breathing through the nose. Air caught in nasal cavities – namely the sinus cavities, cannot be released and the resulting pressure may cause a headache or facial pain. If the sinus passage remains blocked, there is a chance that sinusitis may result. If the mucus backs up through the Eustachian tube, it may result in ear pain or an ear infection. Excess mucus accumulating in the throat or back of the nose may cause a post-nasal drip, resulting in a sore throat or coughing. Additional symptoms include sneezing, nosebleeds, and nasal discharge. | Rhinorrhea | Wikipedia | 397 | 2143933 | https://en.wikipedia.org/wiki/Rhinorrhea | Biology and health sciences | Symptoms and signs | Health |
Causes
A runny nose can be caused by anything that irritates or inflames the nasal tissues, including infections such as the common cold and influenza, and allergies and various irritants. Some people have a chronically runny nose for no apparent reason (non-allergic rhinitis or vasomotor rhinitis). Less common causes include polyps, a foreign body, a tumor or migraine-like headaches. Some causes of rhinorrhea include: acute sinusitis (nasal and sinus infection), allergies, chronic sinusitis, common cold, coronaviruses (COVID-19), decongestant nasal spray overuse, deviated septum, dry air, eosinophilic granulomatosis with polyangiitis, granulomatosis with polyangiitis, hormonal changes, influenza (flu), lodged object, medicines (such as those used to treat high blood pressure, erectile dysfunction, depression, seizures and other conditions), nasal polyps, non-allergic rhinitis (chronic congestion or sneezing not related to allergies), occupational asthma, pregnancy, respiratory syncytial virus (RSV), spinal fluid leak, and tobacco smoke.
Cold temperatures
Rhinorrhea is especially common in cold weather. Cold-induced rhinorrhea occurs due to a combination of thermodynamics and the body's natural reactions to cold weather stimuli. One of the purposes of nasal mucus is to warm inhaled air to body temperature as it enters the body; this requires the nasal cavities to be constantly coated with liquid mucus. In cold weather the mucus lining nasal passages tends to dry out, so that mucous membranes must work harder, producing more mucus to keep the cavity lined. As a result, the nasal cavity can fill up with mucus. At the same time, when air is exhaled, water vapor in breath condenses as the warm air meets the colder outside temperature near the nostrils. This causes excess water to build up inside nasal cavities, spilling out through the nostrils.
Inflammatory | Rhinorrhea | Wikipedia | 439 | 2143933 | https://en.wikipedia.org/wiki/Rhinorrhea | Biology and health sciences | Symptoms and signs | Health |
Infection
Rhinorrhea can be a symptom of other diseases, such as the common cold or influenza. During these infections, the nasal mucous membranes produce excess mucus, filling the nasal cavities. This is to prevent infection from spreading to the lungs and respiratory tract, where it could cause far worse damage. It has also been suggested that viral rhinorrhea is a result of viral evolution whereby virus variants that increase nasal secretion and are thus more resistant to the body's immune defenses are selected for. Rhinorrhea caused by these infections usually occur on circadian rhythms. Over the course of a viral infection, sinusitis (the inflammation of the nasal tissue) may occur, causing the mucous membranes to release more mucus. Acute sinusitis consists of the nasal passages swelling during a viral infection. Chronic sinusitis occurs when sinusitis continues for longer than three months.
Allergies
Rhinorrhea can also occur when individuals with allergies to certain substances, such as pollen, dust, latex, soy, shellfish, or animal dander, are exposed to these allergens. In people with sensitized immune systems, the inhalation of one of these substances triggers the production of the antibody immunoglobulin E (IgE), which binds to mast cells and basophils. IgE bound to mast cells are stimulated by pollen and dust, causing the release of inflammatory mediators such as histamine. In the nasal cavities, these inflammatory mediators cause inflammation and swelling of the tissue, as well as increased mucus production. Particulate matter in polluted air and chemicals such as chlorine and detergents, which can normally be tolerated, can make the condition considerably worse.
Crying
Rhinorrhea is also associated with shedding tears (lacrimation), whether from emotional events or from eye irritation. When excess tears are produced, the liquid drains through the inner corner of the eyelids, through the nasolacrimal duct, and into the nasal cavities. As more tears are shed, more liquid flows into the nasal cavities, both stimulating mucus production and hydrating any dry mucus already present in the nasal cavity. The buildup of fluid is usually resolved via mucus expulsion through the nostrils.
Non-inflammatory
Head trauma | Rhinorrhea | Wikipedia | 477 | 2143933 | https://en.wikipedia.org/wiki/Rhinorrhea | Biology and health sciences | Symptoms and signs | Health |
Rhinorrhea can be caused by a head injury, a serious condition. A basilar skull fracture can result in a rupture of the barrier between the sinonasal cavity and the anterior cranial fossae or the middle cranial fossae. This can cause the nasal cavity to fill with cerebrospinal fluid (cerebrospinal fluid rhinorrhoea, CSF rhinorrhea), a condition that can lead to a number of serious complications, including death if not addressed properly.
Other causes
Rhinorrhea can occur as a symptom of opioid withdrawal accompanied by lacrimation. Other causes include cystic fibrosis, whooping cough, nasal tumors, hormonal changes, and cluster headaches. Rhinorrhea can also be the side effect of several genetic disorders, such as primary ciliary dyskinesia, as well as common irritants such as spicy foods, nail polish remover, or paint fumes.
Treatment
In most cases, treatment for rhinorrhea is not necessary since it will clear up on its own, especially if it is the symptom of an infection. For general cases nose-blowing can get rid of the mucus buildup. Though blowing may be a quick-fix solution, it increases mucosal production in the sinuses, leading to frequent and higher mucus buildups in the nose in the medium term. Alternatively, saline or vasoconstrictor nasal sprays may be used, but may become counterproductive after several days of use, causing rhinitis medicamentosa.
In some cases, such as those due to allergies or sinus infections, there are medicinal treatments available. Several types of antihistamines can be obtained relatively cheaply to treat cases caused by allergies; antibiotics may help in cases of bacterial sinus infections. | Rhinorrhea | Wikipedia | 385 | 2143933 | https://en.wikipedia.org/wiki/Rhinorrhea | Biology and health sciences | Symptoms and signs | Health |
Toxaphene was an insecticide used primarily for cotton in the southern United States during the late 1960s and the 1970s. Toxaphene is a mixture of over 670 different chemicals and is produced by reacting chlorine gas with camphene. It can be most commonly found as a yellow to amber waxy solid.
Toxaphene was banned in the United States in 1990 and was banned globally by the 2001 Stockholm Convention on Persistent Organic Pollutants. It is a very persistent chemical that can remain in the environment for 1–14 years without degrading, particularly in the soil.
Testing performed on animals, mostly rats and mice, has demonstrated that toxaphene is harmful to animals. Exposure to toxaphene has proven to stimulate the central nervous system, as well as induce morphological changes in the thyroid, liver, and kidneys.
Toxaphene has been shown to cause adverse health effects in humans. The main sources of exposure are through food, drinking water, breathing contaminated air, and direct contact with contaminated soil. Exposure to high levels of toxaphene can cause damage to the lungs, nervous system, liver, kidneys, and in extreme cases, may even cause death. It is thought to be a potential carcinogen in humans, though this has not yet been proven.
Composition
Toxaphene is a synthetic organic mixture composed of over 670 chemicals, formed by the chlorination of camphene (C10H16) to an overall chlorine content of 67–69% by weight. The bulk of the compounds (mostly chlorobornanes, chlorocamphenes, and other bicyclic chloroorganic compounds) found in toxaphene have chemical formulas ranging from C10H11Cl5 to C10H6Cl12, with a mean formula of C10H10Cl8. The formula weights of these compounds range from 308 to 551 grams/mole; the theoretical mean formula has a value of 414 grams/mole. Toxaphene is usually seen as a yellow to amber waxy solid with a piney odor. It is highly insoluble in water but freely soluble in aromatic hydrocarbons and readily soluble in aliphatic organic solvents. It is stable at room temperature and pressure. It is volatile enough to be transported for long distances through the atmosphere. | Toxaphene | Wikipedia | 487 | 2144540 | https://en.wikipedia.org/wiki/Toxaphene | Technology | Pest and disease control | null |
Applications
Advertisements for Toxaphene were seen in agricultural periodicals such as Farm Journal as early as 1950.
Toxaphene was primarily used as a pesticide for cotton in the southern United States during the late 1960s and 1970s. It was also used on small grains, maize, vegetables, and soybeans. Outside of the realm of crops, it was also used to control ectoparasites such as lice, flies, ticks, mange, and scam mites on livestock. In some cases it was used to kill undesirable fish species in lakes and streams. The breakdown of usage can be summarized: 85% on cotton, 7% to control insect pests on livestock and poultry, 5% on other field crops, 3% on soybeans, and less than 1% on sorghum.
The first recorded usage of toxaphene was in 1966 in the United States, and by the early to mid 1970s, toxaphene was the United States' most heavily used pesticide. Over 34 million pounds of toxaphene were used annually from 1966 to 1976. As a result of Environmental Protection Agency restrictions, annual toxaphene usage fell to 6.6 million pounds in 1982. In 1990, the EPA banned all usage of toxaphene in the United States. Toxaphene is still used in countries outside the United States but much of this usage has been undocumented. Between 1970 and 1995, global usage of toxaphene was estimated to be 670 million kilograms (1.5 billion pounds).
Production
Toxaphene was first produced in the United States in 1947 although it was not heavily used until 1966. By 1975, toxaphene production reached its peak at 59.4 million pounds annually. Production decreased more than 90% from this value by 1982 due to Environmental Protection Agency restrictions. Overall, an estimated 234,000 metric tons (over 500 million pounds) have been produced in the United States. Between 25% and 35% of the toxaphene produced in the United States has been exported. There are currently 11 toxaphene suppliers worldwide. | Toxaphene | Wikipedia | 436 | 2144540 | https://en.wikipedia.org/wiki/Toxaphene | Technology | Pest and disease control | null |
Environmental effects
When released into the environment, toxaphene can be quite persistent and exists in the air, soil, and water. In water, it can evaporate easily and is fairly insoluble. Its solubility is 3 mg/L of water at 22 degrees Celsius. Toxaphene breaks down very slowly and has a half-life of up to 12 years in the soil. It is most commonly found in air, soil, and sediment found at the bottom of lakes or streams. It can also be present in many parts of the world where it was never used because toxaphene is able to evaporate and travel long distances through air currents. Toxaphene can eventually be degraded, through dechlorination, in the air using sunlight to break it down. The degradation of toxaphene usually occurs under aerobic conditions. The levels of toxaphene have decreased since its ban. However, due to its persistence, it can still be found in the environment today.
Exposure
The three main paths of exposure to toxaphene are ingestion, inhalation, and absorption. For humans, the main source of toxaphene exposure is through ingested seafood. When toxaphene enters the body, it usually accumulates in fatty tissues. It is broken down through dechlorination and oxidation in the liver, and the byproducts are eliminated through feces.
People that live near an area that has high toxaphene contamination are at high risk to toxaphene exposure through inhalation of contaminated air or direct skin contact with contaminated soil or water. Eating large quantities of fish on a daily basis also increases susceptibility to toxaphene exposure. Finally, exposure is rare, yet possible through drinking water when contaminated by toxaphene runoff from the soil. However, toxaphene has been rarely seen at high levels in drinking water due to toxaphene's nearly complete insolubility in water.
Shellfish, algae, fish and marine mammals have all been shown to exhibit high levels of toxaphene. People in the Canadian Arctic, where a traditional diet consists of fish and marine animals, have been shown to consume ten times the accepted daily intake of toxaphene. Also, blubber from beluga whales in the Arctic were found to have unhealthy and toxic levels of toxaphene.
Health effects | Toxaphene | Wikipedia | 502 | 2144540 | https://en.wikipedia.org/wiki/Toxaphene | Technology | Pest and disease control | null |
In humans
When inhaled or ingested, sufficient quantities of toxaphene can damage the lungs, nervous system, and kidneys, and may cause death. The major health effects of toxaphene involve central nervous system stimulation leading to convulsive seizures. The dose necessary to induce nonfatal convulsions in humans is about 10 milligrams per kilogram body weight per day. Several deaths linked to toxaphene have been documented in which an unknown quantity of toxaphene was ingested intentionally or accidentally from food contamination. The deaths are attributed to respiratory failure resulting from seizures. Chronic inhalation exposure in humans results in reversible respiratory toxicity.
A study conducted between 1954 and 1972 of male agricultural workers and agronomists exposed to toxaphene and other pesticides showed that there are higher proportions of bronchial carcinoma in the test group than in the unexposed general population. However, toxaphene may not have been the main pesticide responsible for tumor production. Tests on lab animals show that toxaphene causes liver and kidney cancer, so the EPA has classified it as a Group B2 carcinogen, meaning it is a probable human carcinogen. The International Agency for Research on Cancer has classified it as a Group 2B carcinogen.
Toxaphene can be detected in blood, urine, breast milk, and body tissues if a person has been exposed to high levels, but it is removed from the body quickly, so detection has to occur within several days of exposure.
It is not known whether toxaphene can affect reproduction in humans.
In animals
Toxaphene was used to treat mange in cattle in California in the 1970s and there were reports of cattle deaths following the toxaphene treatment.
Chronic oral exposure in animals affects the liver, the kidney, the spleen, the adrenal and thyroid glands, the central nervous system, and the immune system. Toxaphene stimulates the central nervous system by antagonizing neurons leading to hyperpolarization of neurons and increased neuronal activity. | Toxaphene | Wikipedia | 433 | 2144540 | https://en.wikipedia.org/wiki/Toxaphene | Technology | Pest and disease control | null |
Regulations
Toxaphene has been found on at least 68 of the 1,699 National Priorities List sites identified by the United States Environmental Protection Agency. Toxaphene has been forbidden in Germany since 1980. Most uses of toxaphene were cancelled in the U.S. in 1982 with the exception of use on livestock in emergency situations, and for controlling insects on banana and pineapple crops in Puerto Rico and the U.S. Virgin Islands. All uses of toxaphene were cancelled in the U.S. in 1990.
Toxaphene has been banned in 37 countries, including Austria, Belize, Brazil, Costa Rica, Dominican Republic, Egypt, the EU, India, Ireland, Kenya, Korea, Mexico, Panama, Singapore, Thailand and Tonga. Its use has been severely restricted in 11 other countries, including Argentina, Columbia, Dominica, Honduras, Nicaragua, Pakistan, South Africa, Turkey, and Venezuela.
In the Stockholm Convention on POPs, which came into effect on 17 May 2004, twelve POPs were listed to be eliminated or their production and use restricted. The OCPs or pesticide-POPs identified on this list have been termed the "dirty dozen" and include aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, hexachlorobenzene, mirex, and toxaphene.
The EPA has determined that lifetime exposure to 0.01 milligrams per liter of toxaphene in the drinking water is not expected to cause any adverse noncancer effects if the only source of exposure is drinking water, and has established the maximum contaminant level (MCL) of toxaphene at 0.003 mg/L. The United States Food and Drug Administration (FDA) uses the same level for the maximum level permissible in bottled water.
The FDA has determined that the concentration of toxaphene in bottled drinking water should not exceed 0.003 milligrams per liter.
The United States Department of Transportation lists toxaphene as a hazardous material and has special requirements for marking, labeling, and transporting the material.
It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities. | Toxaphene | Wikipedia | 508 | 2144540 | https://en.wikipedia.org/wiki/Toxaphene | Technology | Pest and disease control | null |
Trade names
Trade names and synonyms include Chlorinated camphene, Octachlorocamphene, Camphochlor, Agricide Maggot Killer, Alltex, Allotox, Crestoxo, Compound 3956, Estonox, Fasco-Terpene, Geniphene, Hercules 3956, M5055, Melipax, Motox, Penphene, Phenacide, Phenatox, Strobane-T, Toxadust, Toxakil, Vertac 90%, Toxon 63, Attac, Anatox, Royal Brand Bean Tox 82, Cotton Tox MP82, Security Tox-Sol-6, Security Tox-MP cotton spray, Security Motox 63 cotton spray, Agro-Chem Brand Torbidan 28, and Dr Roger's TOXENE. | Toxaphene | Wikipedia | 188 | 2144540 | https://en.wikipedia.org/wiki/Toxaphene | Technology | Pest and disease control | null |
Waru Waru is an Aymara term for the agricultural technique developed by pre-Hispanic people in the Andes region of South America from Ecuador to Bolivia; this regional agricultural technique is also referred to as camellones in Spanish. Functionally similar agricultural techniques have been developed in other parts of the world, all of which fall under the broad category of raised field agriculture.
This type of altiplano field agriculture consists of parallel canals alternated by raised planting beds, which would be strategically located on floodplains or near a water source so that the fields could be properly irrigated. These flooded fields were composed of soil that was rich in nutrients due to the presence of aquatic plants and other organic materials. Through the process of mounding up this soil to create planting beds, natural, recyclable fertilizer was made available in a region where nitrogen-rich soils were rare. By trapping solar radiation during the day, this raised field agricultural method also protected crops from freezing overnight. These raised planting beds were irrigated very efficiently by the adjacent canals which extended the growing season significantly, allowing for more food yield. Waru Waru were able to yield larger amounts of food than previous agricultural methods due to the overall efficiency of the system.
This technique is dated to around 300 B.C., and is most commonly associated with the Tiwanaku culture of the Lake Titicaca region in southern Bolivia, who used this method to grow crops like potatoes and quinoa. This type of agriculture also created artificial ecosystems, which attracted other food sources such as fish and lake birds. Past cultures in the Lake Titicaca region likely utilized these additional resources as a subsistence method. It combines raised beds with irrigation channels to prevent damage by soil erosion during floods. These fields ensure both collecting of water (either fluvial water, rainwater or phreatic water) and subsequent drainage. The drainage aspect of this method makes it particularly useful in many areas subjected to risks of brutal floods, such as tropical parts of Bolivia and Peru where it emerged. Raised field agricultural methods have been used in many other countries such as China, Mexico and Belize. Mexican Chinampas were similar to Waru Waru in that they were created on or near a water source in order to properly irrigate crops. Raised fields are known in Belize from various sites, including Pulltrouser Swamp. | Waru Waru | Wikipedia | 480 | 15865266 | https://en.wikipedia.org/wiki/Waru%20Waru | Technology | Buildings and infrastructure | null |
Modern Uses
In the 1960s, geographers William Denevan, George Plafker, and Kenneth Lee found evidence of raised-field agriculture that had been utilized in the Llanos de Moxos region of Bolivia's Amazon basin, a region that was previously thought to have been unable to sustain large-scale agriculture because of what was believed to have been an unfavorable rainforest environment. This discovery led to a joint experimental archaeology project in the region involving archaeologist Clark Erickson, the Inter-American Foundation, the Parroquia of San Ignacio, the Bolivian Institute of Archaeology, and the University of Pennsylvania Museum of Archaeology and Anthropology. The goal of this experiment was to attempt to restore indigenous raised-field agriculture in the region. This project began in 1990 at the Biological Station of the Beni Department in Bolivia. Because of the experiment's success, it was later implemented further in collaboration with local indigenous communities. The indigenous community provided land for the project and the Inter-American Foundation paid them wages to build and maintain the plots, which successfully produced manioc and maize. These plots did not require extensive upkeep following the initial season's planting, and were self-sufficient because of the artificial ecosystems that they created.
This agricultural method was also revived by Alan Kolata of the University of Chicago in 1984, in Tiwanaku, Bolivia as well as Puno, Peru. Research on Waru Waru and its effectiveness in the past has led to a resurgence of the technique amongst contemporary Aymara- and Quechua-speaking native peoples in Bolivia and Peru. By utilizing this centuries-old technique, modern people in the region have been able to make use of the harsh altiplano landscape around Lake Titicaca. This method is now being used in different areas of South America where farming is difficult, such as the altiplano and the Amazon basin. Because of this method, indigenous people are now able to farm the landscape much more efficiently and without the use of modern equipment. This method also allows for large-scale agriculture to be performed in the Amazon basin without having to rely on deforestation. | Waru Waru | Wikipedia | 433 | 15865266 | https://en.wikipedia.org/wiki/Waru%20Waru | Technology | Buildings and infrastructure | null |
Experiments
Research was done at two raised-field sites by Diego Sanchez de Lozada et al. in the northern altiplano of Bolivia near Lake Titicaca in an effort to better understand the effects of frost on potato crops. At an altitude of , these crops were subject to temperature and moisture variation. Temperatures of the soil on top of the high raised mounds was about 1 degree Celsius higher than the temperature of the ground in nearby fields, showing that the raised-field technique was able to partially mitigate frost effects on potato crops at night. Temperature and moisture analysis of the raised fields showed that the higher temperature present was due to above-ground processes, which caused cold air to fall to the canals and not on the planted rows. The frost mitigation effects of the raised field system kept crops from freezing overnight, which increased crop yield.
History
Lake Titicaca Region
16th Century Spanish accounts of the Lake Titicaca region mentioned the different types of agriculture utilized by the native peoples in detail, however there was never any mention of raised fields in their records. The lack of Spanish accounts strongly suggests that these Waru Waru were no longer in use by the time the conquistadors reached the Lake Titicaca region.
The raised fields of the region are numerous and range in size, however they are generally wide, long, and tall. These pre-Hispanic fields cover about of land in Bolivia and Peru, and sit above an altitude of around 3,800 m. Radiocarbon dates taken from habitation sites associated with raised field agriculture in the region indicate usage sometimes between 1000 B.C. to A.D. 400. Thermoluminescence dating was also used to date pottery shards in associated areas, the results of which agree with the radiocarbon dates. Field stratigraphy was used to provide relative dates of the usage of certain raised fields in the area. The habitation sites in association with these fields indicate large populations and long-term occupations, suggesting that raised field agriculture was able to sustain large numbers of people. These dates provided from Andean sites suggest that this form of agriculture was a relatively early phenomenon in the area that slowly expanded throughout the region, and was utilized by various cultures during different time periods. | Waru Waru | Wikipedia | 454 | 15865266 | https://en.wikipedia.org/wiki/Waru%20Waru | Technology | Buildings and infrastructure | null |
In magnetostatics, the force of attraction or repulsion between two current-carrying wires (see first figure below) is often called Ampère's force law. The physical origin of this force is that each wire generates a magnetic field, following the Biot–Savart law, and the other wire experiences a magnetic force as a consequence, following the Lorentz force law.
Equation
Special case: Two straight parallel wires
The best-known and simplest example of Ampère's force law, which underlaid (before 20 May 2019) the definition of the ampere, the SI unit of electric current, states that the magnetic force per unit length between two straight parallel conductors is
where is the magnetic force constant from the Biot–Savart law, is the total force on either wire per unit length of the shorter (the longer is approximated as infinitely long relative to the shorter), is the distance between the two wires, and , are the direct currents carried by the wires.
This is a good approximation if one wire is sufficiently longer than the other, so that it can be approximated as infinitely long, and if the distance between the wires is small compared to their lengths (so that the one infinite-wire approximation holds), but large compared to their diameters (so that they may also be approximated as infinitely thin lines). The value of depends upon the system of units chosen, and the value of decides how large the unit of current will be.
In the SI system,
with the magnetic constant, in SI units
General case
The general formulation of the magnetic force for arbitrary geometries is based on iterated line integrals and combines the Biot–Savart law and Lorentz force in one equation as shown below. | Ampère's force law | Wikipedia | 352 | 15868921 | https://en.wikipedia.org/wiki/Amp%C3%A8re%27s%20force%20law | Physical sciences | Magnetostatics | Physics |
where
is the total magnetic force felt by wire 1 due to wire 2 (usually measured in newtons),
and are the currents running through wires 1 and 2, respectively (usually measured in amperes),
The double line integration sums the force upon each element of wire 1 due to the magnetic field of each element of wire 2,
and are infinitesimal vectors associated with wire 1 and wire 2 respectively (usually measured in metres); see line integral for a detailed definition,
The vector is the unit vector pointing from the differential element on wire 2 towards the differential element on wire 1, and |r| is the distance separating these elements,
The multiplication × is a vector cross product,
The sign of is relative to the orientation (for example, if points in the direction of conventional current, then ).
To determine the force between wires in a material medium, the magnetic constant is replaced by the actual permeability of the medium.
For the case of two separate closed wires, the law can be rewritten in the following equivalent way by expanding the vector triple product and applying Stokes' theorem:
In this form, it is immediately obvious that the force on wire 1 due to wire 2 is equal and opposite the force on wire 2 due to wire 1, in accordance with Newton's third law of motion.
Historical background
The form of Ampere's force law commonly given was derived by James Clerk Maxwell in 1873 and is one of several expressions consistent with the original experiments of André-Marie Ampère and Carl Friedrich Gauss.
The x-component of the force between two linear currents I and I, as depicted in the adjacent diagram, was given by Ampère in 1825 and Gauss in 1833 as follows:
Following Ampère, a number of scientists, including Wilhelm Weber, Rudolf Clausius, Maxwell, Bernhard Riemann, Hermann Grassmann, and Walther Ritz, developed this expression to find a fundamental expression of the force. Through differentiation, it can be shown that:
and also the identity:
With these expressions, Ampère's force law can be expressed as:
Using the identities:
and
Ampère's results can be expressed in the form:
As Maxwell noted, terms can be added to this expression, which are derivatives of a function Q(r) and, when integrated, cancel each other out. Thus, Maxwell gave "the most general form consistent with the experimental facts" for the force on ds arising from the action of ds': | Ampère's force law | Wikipedia | 495 | 15868921 | https://en.wikipedia.org/wiki/Amp%C3%A8re%27s%20force%20law | Physical sciences | Magnetostatics | Physics |
Q is a function of r, according to Maxwell, which "cannot be determined, without assumptions of some kind, from experiments in which the active current forms a closed circuit." Taking the function Q(r) to be of the form:
We obtain the general expression for the force exerted on ds by ds''' :
Integrating around s' eliminates k and the original expression given by Ampère and Gauss is obtained. Thus, as far as the original Ampère experiments are concerned, the value of k has no significance. Ampère took k=−1; Gauss took k=+1, as did Grassmann and Clausius, although Clausius omitted the S component. In the non-ethereal electron theories, Weber took k=−1 and Riemann took k=+1. Ritz left k undetermined in his theory. If we take k = −1, we obtain the Ampère expression:
If we take k=+1, we obtain
Using the vector identity for the triple cross product, we may express this result as
When integrated around ds' the second term is zero, and thus we find the form of Ampère's force law given by Maxwell:
Derivation of parallel straight wire case from general formula
Start from the general formula:
Assume wire 2 is along the x-axis, and wire 1 is at y=D, z=0, parallel to the x-axis. Let be the x-coordinate of the differential element of wire 1 and wire 2, respectively. In other words, the differential element of wire 1 is at and the differential element of wire 2 is at . By properties of line integrals, and . Also,
and
Therefore, the integral is
Evaluating the cross-product:
Next, we integrate from to :
If wire 1 is also infinite, the integral diverges, because the total attractive force between two infinite parallel wires is infinity. In fact, what we really want to know is the attractive force per unit length'' of wire 1. Therefore, assume wire 1 has a large but finite length . Then the force vector felt by wire 1 is:
As expected, the force that the wire feels is proportional to its length. The force per unit length is:
The direction of the force is along the y-axis, representing wire 1 getting pulled towards wire 2 if the currents are parallel, as expected. The magnitude of the force per unit length agrees with the expression for shown above.
Notable derivations
Chronologically ordered:
Ampère's original 1823 derivation: | Ampère's force law | Wikipedia | 512 | 15868921 | https://en.wikipedia.org/wiki/Amp%C3%A8re%27s%20force%20law | Physical sciences | Magnetostatics | Physics |
Maxwell's 1873 derivation:
Treatise on Electricity and Magnetism vol. 2, part 4, ch. 2 (§§502–527)
Pierre Duhem's 1892 derivation:
(EPUB)
translation of: Leçons sur l'électricité et le magnétisme vol. 3, appendix to book 14, pp. 309-332
Alfred O'Rahilly's 1938 derivation:
Electromagnetic Theory: A Critical Examination of Fundamentals vol. 1, pp. 102–104 (cf. the following pages, too) | Ampère's force law | Wikipedia | 111 | 15868921 | https://en.wikipedia.org/wiki/Amp%C3%A8re%27s%20force%20law | Physical sciences | Magnetostatics | Physics |
The Pelagornithidae, commonly called pelagornithids, pseudodontorns, bony-toothed birds, false-toothed birds or pseudotooth birds, are a prehistoric family of large seabirds. Their fossil remains have been found all over the world in rocks dating between the Early Paleocene and the Pliocene-Pleistocene boundary.
Most of the common names refer to these birds' most notable trait: tooth-like points on their beak's edges, which, unlike true teeth, contained Volkmann's canals and were outgrowths of the premaxillary and mandibular bones. Even "small" species of pseudotooth birds were the size of albatrosses; the largest ones had wingspans estimated at 5–6 metres (15–20 ft) and were among the largest flying birds ever to live. They were the dominant seabirds of most oceans throughout most of the Cenozoic, and modern humans apparently missed encountering them only by a tiny measure of evolutionary time: the last known pelagornithids were contemporaries of Homo habilis and the beginning of the history of technology.
Description and ecology
The biggest of the pseudotooth birds were the largest flying birds known. Almost all of their remains from the Neogene are immense, but in the Paleogene there were a number of pelagornithids that were around the size of a great albatross (genus Diomedea) or even a bit smaller. The undescribed species provisionally called "Odontoptila inexpectata" – from the Paleocene-Eocene boundary of Morocco – is the smallest pseudotooth bird discovered to date and was just a bit larger than a white-chinned petrel (Procellaria aequinoctialis). | Pelagornithidae | Wikipedia | 370 | 9205088 | https://en.wikipedia.org/wiki/Pelagornithidae | Biology and health sciences | Prehistoric birds | Animals |
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