Member states.

SADC has 16 member states: The Union of Comoros was admitted into SADC at the 37th SADC Summit of Heads of State and Government held in Pretoria, South Africa in 2017, bringing the total number of Member States to 16. Additionally, Burundi has requested to join.

History.

The origins of SADC are in the 1960s and 1970s, when the leaders of majority-ruled countries and national liberation movements coordinated their political, diplomatic and military struggles to bring an end to colonial and white-minority rule in southern Africa. The immediate forerunner of the political and security cooperation leg of today's SADC was the informal Frontline States (FLS) grouping. It was formed in 1980.  The Southern African Development Coordination Conference (SADCC) was the forerunner of the socio-economic cooperation leg of today's SADC. The adoption by nine majority-ruled southern African countries of the Lusaka declaration on 1 April 1980 paved the way for the formal establishment of SADCC in April 1980.  Membership of the FLS and SADCC sometimes differed.  SADCC was transformed into SADC on 17 August 1992, with the adoption by the founding members of SADCC and newly independent Namibia of the Windhoek declaration and treaty establishing SADC. The 1992 SADC provided for both socio-economic cooperation and political and security cooperation. In reality, the FLS was dissolved only in 1994, after South Africa's first democratic elections. Subsequent efforts to place political and security cooperation on a firm institutional footing under SADC's umbrella failed.  On 14 August 2001, the 1992 SADC treaty was amended. The amendment heralded the overhaul of the structures, policies and procedures of SADC, a process which is ongoing. One of the changes is that political and security cooperation is institutionalised in the Organ on Politics, Defence and Security (OPDS). One of the principal SADC bodies, it is subject to the oversight of the organisation's supreme body, the Summit, which comprises the heads of state or government.  The organisation holds its own multi-sport event in the form of the SADC Games, which was first held in 2004 in Maputo. Originally planned for an earlier date in Malawi and Lesotho, organisational issues led to abandonment of the plan and the SADC issuing a fine of $100,000 against Malawi. The first event in 2004 in Maputo resulted in over 1000 youths under-20 from 10 countries taking part in a sports programme including athletics, football, netball, boxing and basketball.

Protocols.

SADC has 27 legally binding protocols dealing with issues such as Defence, Development, Illicit Drug Trade, Free Trade and Movement of People.

SADC FTA.

The SADC Free Trade Area was established in August 2008, after the implementation of the SADC Protocol on Trade in 2000 laid the foundation for its formation. Its original members were Botswana, Lesotho, Madagascar, Mauritius, Mozambique, Namibia, South Africa, Eswatini, Tanzania, Zambia and Zimbabwe, with Malawi and Seychelles joining later. Of the 15 SADC member states, only Angola and the Democratic Republic of Congo are not yet participating, however Angolan trade minister Joffre Van-Dúnen Júnior said in Luanda that his ministry is working to create conditions for Angola's accession to the SADC Free Trade Area in 2019. The SADC-Customs Union, scheduled to be established by 2010 according to SADC's Regional Indicative Strategic Development Plan (RISDP), is unlikely to become reality in the near future. This is because the European Union's Economic Partnership Agreements (EPA) with their inherent extra-regional freetrade regimes provided for several SADC members more benefits than deeper regional market integration within the framework of a SADC-Customs Union. Since these SADC countries formed four different groupings to negotiate and implement different Economic Partnership Agreements with European Union, the chance to establish a SADC-wide common external tariff as prerequisite for a regional customs union is missed.  On Wednesday 22 October 2008, SADC joined with the Common Market for Eastern and Southern Africa and the East African Community to form the African Free Trade Zone, including all members of each of the organizations. The leaders of the three trading blocs agreed to create a single free trade zone, the African Free Trade Zone, consisting of 26 countries with a GDP of an estimated $624bn (£382.9bn). It is hoped the African Free Trade Zone agreement would ease access to markets within the zone and end problems arising from the fact that several of the member countries belong to multiple groups.  The African Free Trade Zone effective has been more than a hundred years in the making—a trade zone spanning the whole African continent from Cape to Cairo and envisioned by Cecil Rhodes and other British imperialists in the 1890s. The only difference is that the African Free Trade Zone is the creation of independent African Countries. The idea is a free trade zone spanning the whole continent from the Cape to Cairo (Cape Town in the Republic of South Africa to Cairo in Egypt).  In addition to eliminating duplicative membership and the problem member states also participating in other regional economic cooperation schemes and regional political and security cooperation schemes that may compete with or undermine each other, the African Free Trade Zone further aims to strengthen the bloc's bargaining power when negotiating international deals.

Challenges facing member countries.

SADC countries face many social, development, economic, trade, education, health, diplomatic, defence, security and political challenges. Some of these challenges cannot be tackled effectively by individual members. Cattle diseases and organised-crime gangs know no boundaries. War in one country can suck in its neighbours and damage their economies. The sustainable development that trade could bring is threatened by the existence of different product standards and tariff regimes, weak customs infrastructure and bad roads. The socio-economic and political and security cooperation aims of SADC are equally wide-ranging, and intended to address the various common challenges.  One significant challenge is that member states also participate in other regional economic cooperation schemes and regional political and security cooperation schemes that may compete with or undermine SADC's aims. For example, South Africa and Botswana both belong to the Southern Africa Customs Union, Zambia is a part of the Common Market for Eastern and Southern Africa, and Tanzania is a member of the East African Community.  According to Human Rights Watch, "SADC has been criticized for its laxity on making human rights compliance within its member states a priority".

Structure and decision-making procedures.

The organisation has six principal bodies:  Except for the Tribunal (based in Windhoek, Namibia), SNCs and Secretariat, decision-making is by consensus.

The Southern African Development Community (SADC) is an inter-governmental organization headquartered in Gaborone, Botswana. Its goal is to further socio-economic cooperation and integration as well as political and security cooperation among 16 southern African countries.


Background.

Maalouf was born in Beirut, Lebanon, and grew up in the Badaro cosmopolitan neighborhood, the second of four children. His parents had different cultural backgrounds. His mother, Odette Ghossein, is Lebanese of Turkish descent, from the Metn Village of Ain el Kabou, she was born in Egypt and lived there for many years before coming back to Lebanon. She currently lives in France. His father was from the Melkite Catholic community near the village of Baskinta in Ain el Qabou. Maalouf's mother was a staunch Maronite Catholic who insisted on sending him to Collège Notre Dame de Jamhour, a French Jesuit school. He studied sociology at the Francophone Université Saint-Joseph in Beirut.

Career.

Maalouf worked as the director of the Beirut-based daily newspaper "An-Nahar" until the start of the Lebanese civil war in 1975, when he moved to Paris, which became his permanent home.  Maalouf's first book, "The Crusades Through Arab Eyes", 1983, examined the period on the basis of contemporaneous Arabic sources.  Besides novels, he has written four texts for musical compositions and several works of non-fiction, of which "Crusades through Arab Eyes" is probably the best known.  In 2011, he was elected to seat #29 of the Académie française, a chair previously held by Ernst Renan. He is trumpeter Ibrahim Maalouf's uncle.

Awards.

In 1993, Maalouf was awarded the Prix Goncourt for his novel The Rock of Tanios (""Le rocher de Tanios")", set in 19th-century Lebanon. In 2010 he received the Spanish Prince of Asturias Award for Literature for his work, an intense mix of suggestive language, historic affairs in a Mediterranean mosaic of languages, cultures and religions and stories of tolerance and reconciliation.  He was elected a member of the Académie française on 23 June 2011 to fill seat 29, left vacant by the death of anthropologist Claude Lévi-Strauss. Maalouf is the first person of Lebanese heritage to receive that honor. His book "Un fauteuil sur la Seine" briefly recounts the lives of those who preceded him in seat 29.  Maalouf has been awarded honorary doctorates by the Catholic University of Louvain (Belgium), the American University of Beirut (Lebanon), the Rovira i Virgili University (Spain), the University of Évora (Portugal), and the University of Ottawa (Canada).  In 2016, he won the Sheikh Zayed Book Award for "Cultural Personality of the Year", the premier category with a prize of 1 million dirhams.  In 2020, he was awarded the National Order of Merit by the French government. He was given the honor by President Emmanuel Macron.

Works.

Fiction.

Maalouf's novels are marked by his experiences of civil war and migration. Their characters are itinerant voyagers between lands, languages, and religions and he prefers to write about "our past".

Librettos.

All Maalouf's librettos have been written for the Finnish composer Kaija Saariaho.

Amin Maalouf (; ; born 25 February 1949) is a Lebanese-born French author who has lived in France since 1976. Although his native language is Arabic, he writes in French, and his works have been translated into over 40 languages. He received the Prix Goncourt in 1993 for his novel "The Rock of Tanios" as well as the 2010 Prince of Asturias Award for Literature. He is a member of the Académie française.


Habitat, behavior and diet.

Fire salamanders live in central Europe forests and are more common in hilly areas. They prefer deciduous forests since they like to hide in fallen leaves and around mossy tree trunks. They need small brooks or ponds with clean water in their habitat for the development of the larvae. Whether on land or in water, fire salamanders are inconspicuous. They spend much of their time hidden under wood or other objects. They are active in the evening and the night, but on rainy days they are active in the daytime as well.  The diet of the fire salamander consists of various insects, spiders, earthworms and slugs, but they also occasionally eat newts and young frogs. In captivity, they eat crickets, mealworms, waxworms and silkworm larvae. Small prey will be caught within the range of the vomerine teeth or by the posterior half of the tongue, to which the prey adheres. It weighs about 40 grams. The fire salamander can grow to be long.

Reproduction.

Males and females look very similar except during the breeding season when the most conspicuous difference is a swollen gland around the male's vent. This gland produces the spermatophore, which carries a sperm packet at its tip. The courtship happens on land. After the male becomes aware of a potential mate, he confronts her and blocks her path. The male rubs her with his chin to express his interest in mating, then crawls beneath her and grasps her front limbs with his own in amplexus. He deposits a spermatophore on the ground, then attempts to lower the female's cloaca into contact with it. If successful, the female draws the sperm packet in and her eggs are fertilized internally. The eggs develop internally and the female deposits the larvae into a body of water just as they hatch. In some subspecies, the larvae continue to develop within the female until she gives birth to fully formed metamorphs. Breeding has not been observed in neotenic fire salamanders.  In captivity, females may retain sperm long-term and use the stored sperm later to produce another clutch. This behavior has not been observed in the wild, likely due to the ability to obtain fresh sperm and the degradation of stored sperm.

Toxicity.

The fire salamander's primary alkaloid toxin, samandarin, causes strong muscle convulsions and hypertension combined with hyperventilation in all vertebrates. The poison glands of the fire salamander are concentrated in certain areas of the body, especially around the head and the dorsal skin surface. The coloured portions of the animal's skin usually coincide with these glands. Compounds in the skin secretions may be effective against bacterial and fungal infections of the epidermis; some are potentially dangerous to human life.

Distribution.

Fire salamanders are found in most of southern and central Europe. They are most commonly found at altitudes between and, only rarely below (in Northern Germany sporadically down to ). However, in the Balkans or Spain they are commonly found in higher altitudes as well.

Subspecies.

Several subspecies of the fire salamander are recognized. Most notable are the subspecies "fastuosa" and "bernadezi", which are the only viviparous subspecies – the others are ovoviviparous.  Some former subspecies have been lately recognized as species for genetic reasons.

Confirmed hosts of "Batrachochytrium salamandrivorans".

The fire salamander is under threat or has been extinct in certain regions such as the south of the Netherlands and the East of Belgium by the propagation of mycose "Batrachochytrium salamandrivorans" origin.

The fire salamander ("Salamandra salamandra") is possibly the best-known salamander species in Europe. It is black with yellow spots or stripes to a varying degree; some specimens can be nearly completely black while on others the yellow is dominant. Shades of red and orange may sometimes appear, either replacing or mixing with the yellow according to subspecies. Fire salamanders can have a very long lifespan; one specimen lived for more than 50 years in Museum Koenig, a German natural history museum.


History.

Scientists have found ancient mortars and pestles in Southwest Asia that date back to approximately 35000 BC.

Etymology.

The English word "mortar" derives from middle English "morter", from old French "mortier", from classical Latin "mortarium", meaning, among several other usages, "receptacle for pounding" and "product of grinding or pounding". The classical Latin "pistillum", meaning "pounder", led to English "pestle".  The Roman poet Juvenal applied both "mortarium" and "pistillum" to articles used in the preparation of drugs, reflecting the early use of the mortar and pestle as a symbol of a pharmacist or apothecary.  The antiquity of these tools is well documented in early writing, such as the Egyptian Ebers Papyrus of ~1550 BC (the oldest preserved piece of medical literature) and the Old Testament (Numbers 11:8 and Proverbs 27:22).

Uses.

Medicine.

Mortars and pestles were traditionally used in pharmacies to crush various ingredients prior to preparing an extemporaneous prescription. The mortar and pestle, with the Rod of Asclepius, the Green Cross, and others, is one of the most pervasive symbols of pharmacology, along with the show globe.  For pharmaceutical use, the mortar and the head of the pestle are usually made of porcelain, while the handle of the pestle is made of wood. This is known as a Wedgwood mortar and pestle and originated in 1759. Today the act of mixing ingredients or reducing the particle size is known as trituration.  Mortars and pestles are also used as drug paraphernalia to grind up pills to speed up absorption when they are ingested, or in preparation for insufflation. To finely ground drugs, not available in liquid dosage form is used also if patients need artificial nutrition such as parenteral nutrition or by nasogastric tube.

Food preparation.

Mortars are also used in cooking to prepare wet or oily ingredients such as guacamole, hummus and pesto (which derives its name from the pestle pounding), as well as grinding spices into powder. The molcajete, a version used by pre-Hispanic Mesoamerican cultures including the Aztec and Maya, stretching back several thousand years, is made of basalt and is used widely in Mexican cooking. Other Native American nations use mortars carved into the bedrock to grind acorns and other nuts. Many such depressions can be found in their territories.  In Japan, very large mortars are used with wooden mallets to prepare mochi. A regular sized Japanese mortar and pestle are called a "suribachi" and "surikogi", respectively. Granite mortars and pestles are used in Southeast Asia, as well as Pakistan and India. In India, it is used extensively to make spice mixtures for various delicacies as well as day to day dishes. With the advent of motorized grinders, use of the mortar and pestle has decreased. It is traditional in various Hindu ceremonies (such as weddings, and upanayanam) to crush turmeric in these mortars.  In Malay, it is known as "batu lesung". Large stone mortars, with long (2–3 foot) wood pestles were used in West Asia to grind meat for a type of meatloaf, or kibbeh, as well as the hummus variety known as masabcha. In Indonesia and the Netherlands mortar is known as "Cobek" or "Tjobek" and pestle is known as "Ulekan" or "Oelekan". The chobek is shaped lke a deep saucer or plate. The ulekan is either pistol-shaped or an ovoid. It is often used to make fresh sambal, a spicy chili condiment, hence the "sambal ulek/oelek" denote its process using pestle. It is also used to grind peanut and other ingredients to make peanut sauce for gado-gado.

Husking and dehulling.

Large mortars and pestles are commonly used in developing countries to husk and dehull grain. These are usually made of wood, and operated by one or more persons.  In the Philippines, mortar and pestles are specifically associated with de-husking rice. A notable traditional mortar and pestle is the boat-shaped "bangkang pinawa" or "bangkang pangpinawa", literally "boat ("bangka") for unpolished rice", usually carved from a block of molave or other hardwood. It is pounded by two or three people. The name for the mortar, "lusong", is the origin of the name of the largest island in the Philippines - Luzon.

Material.

Good mortar and pestle-making materials must be hard enough to crush the substance rather than be worn away by it. They cannot be too brittle either, or they will break during the pounding and grinding. The material should also be cohesive, so that small bits of the mortar or pestle do not mix in with the ingredients. Smooth and non-porous materials are chosen that will not absorb or trap the substances being ground.  In food preparation, a rough or absorbent material may cause the strong flavour of a past ingredient to be tasted in food prepared later. Also, the food particles left in the mortar and on the pestle may support the growth of microorganisms. When dealing with medications, the previously prepared drugs may interact or mix, contaminating the currently used ingredients.  Rough ceramic mortar and pestle sets can be used to reduce substances to very fine powders, but stain easily and are brittle. Porcelain mortars are sometimes conditioned for use by grinding some sand to give them a rougher surface which helps to reduce the particle size. Glass mortars and pestles are fragile, but stain-resistant and suitable for use with liquids. However, they do not grind as finely as the ceramic type.  Other materials used include stone, often marble or agate, wood (highly absorbent), bamboo, iron, steel, brass, and basalt. Mortar and pestle sets made from the wood of old grape vines have proved reliable for grinding salt and pepper at the dinner table. Uncooked rice is sometimes ground in mortars to clean them. This process must be repeated until the rice comes out completely white. Some stones, such as molcajete, need to be seasoned first before use. Metal mortars are kept lightly oiled.

Automatic mortar grinder.

Since the results obtained with hand grinding are neither reproducible nor reliable, most laboratories work with automatic mortar grinders. Grinding time and pressure of the mortar can be adjusted and fixed, saving time and labor.  The first automatic Mortar Grinder was invented by F. Kurt Retsch in 1923: the "Retschmill".

Advantages.

The use of mortar and pestle, pestling, offers the advantage that the substance is crushed with low energy so that the substance will not warm up.

Folklore.

In Russian tales, Baba Yagá is portrayed as a hag who flies through the air in a mortar, using the pestle as a rudder.

Mortar and pestle are implements used since ancient times to prepare ingredients or substances by crushing and grinding them into a fine paste or powder in the kitchen, laboratory, and pharmacy. The "mortar" () is a bowl, typically made of hard wood, metal, ceramic, or hard stone, such as granite. The "pestle" (, ) is a heavy and blunt club-shaped object. The substance to be ground, which may be wet or dry, is placed in the mortar, where the pestle is pressed and rotated onto it until the desired texture is achieved.


Habitat.

This owl can be found primarily in coniferous forests of the taiga and higher mountainous regions with coniferous and mixed forests. These areas generally have cooler temperatures and higher rainfall than nearby lowland regions. The owl usually lives along the edges of clearings surrounded by moist or swampy land, generally with a water source nearby. It nests in old woodpecker holes, often those of the great spotted woodpecker.

Description.

The Eurasian pygmy owl is usually red-tinged to a greyish-brown with dots on its back. The tail is generally darker than the body with five narrow, whitish bars. It has a small, short head with white to grey eyebrows and yellow eyes. It lacks the ear tufts that many other owls have. There is a white half collar on the back of the neck. The belly is mostly white with brown speckles. The beak is a greyish yellow and hook-shaped.  In order to be able to carry larger vertebrate prey, it has evolved disproportionately large feet. The legs and toes are a brownish-yellow with black talons. Females are 17.4 to 19 centimetres (6.8 to 7.5 inches) long, and males are generally smaller, measuring 15.2 to 17 centimetres (6 to 6.7 inches) in length. Females are about 67 to 77 grams, and males are 50 to 65 grams in weight.

Call.

The call of the Eurasian pygmy owl is much higher in pitch than what is generally perceived as a normal owl "hoot". The call of the male is a monotonous chain of clear, fluted notes spaced by about two seconds. The call of the female is similar, but higher in pitch. Before and after the mating season, both males and females make a five to seven note rise on the pitch scale.

Breeding.

This owl nests in tree cavities, often in old woodpecker holes. It prefers conifers but will occupy birches and beeches. Pairs form in autumn through early spring. During courtship the male leads the female through his territory. If he has obtained a nest hole, he leads her to it. The male will also feed the female.  This species is serially monogamous, forming bonded pairs for one or more breeding seasons. The male is territorial and may use the same nesting territory for up to seven years. The female lays about four to seven eggs, generally in April. They are incubated for four weeks, starting when the third egg is laid. They hatch nearly simultaneously and the female remains with them for nine to ten days, being fed by the male.  After three weeks the young are active and the female returns to the nest only to feed them and clean out waste. Fledging occurs at 30 to 34 days. The chicks remain close to the nest for a few days before departing.

Feeding.

The diet of the Eurasian pygmy owl includes mostly small mammals, such as voles, lemmings, bats, and mice, and small birds such as thrushes, crossbills, chaffinches, and leaf-warblers. They are able to catch birds in flight. Other prey items may include lizards, fish, and insects. The owl may store food during the winter.  This owl is crepuscular, being active during the daylight hours near sunrise and sunset.

The Eurasian pygmy owl ("Glaucidium passerinum") is the smallest owl in Europe. It is a dark reddish to greyish-brown, with spotted sides and half of a white ring around the back of the neck. This species is found in the boreal forests of Northern and Central Europe to Siberia.


Overview.

Lake Tana was formed by volcanic activity, blocking the course of inflowing rivers in the early Pleistocene epoch, about 5 million years ago.  The lake was originally much larger than it is today. Seven large permanent rivers feed the lake as well as 40 small seasonal rivers. The main tributaries to the lake are Gilgel Abbay (Little Nile River), and the Megech, Gumara, and Rib rivers.  Lake Tana has a number of islands, whose number varies depending on the level of the lake. It has fallen about in the last 400 years. According to Manoel de Almeida (a Portuguese missionary in the early 17th century), there were 21 islands, seven to eight of which had monasteries on them "formerly large, but now much diminished." When James Bruce visited the area in the later 18th century, he noted that the locals counted 45 inhabited islands, but stated he believed that "the number may be about eleven." A 20th-century geographer named 37 islands, of which he believed 19 have or had monasteries or churches on them.  Remains of ancient Ethiopian emperors and treasures of the Ethiopian Church are kept in the isolated island monasteries (including Kebran Gabriel, Ura Kidane Mehret, Narga Selassie, Daga Estifanos, Medhane Alem of Rema, Kota Maryam, and Mertola Maryam). On the island of Tana Qirqos is a rock shown to Paul B. Henze, on which he was told the Virgin Mary had rested on her journey back from Egypt; he was also told that Frumentius, who introduced Christianity to Ethiopia, is "allegedly buried on Tana Cherqos." The body of Yekuno Amlak is interred in the monastery of St. Stephen on Daga Island. Emperors whose tombs are also on Daga include Dawit I, Zara Yaqob, Za Dengel, and Fasilides. Other important islands in Lake Tana include Dek, Mitraha, Gelila Zakarias, Halimun and Briguida.  The monasteries are believed to have been built over earlier religious sites. They include the fourteenth-century Debre Maryam, and the eighteenth-century Narga Selassie, Tana Qirqos (said to have housed the Ark of the Covenant before it was moved to Axum), and Ura Kidane Mehret, known for its regalia. A ferry service links Bahir Dar with Gorgora via Dek Island and various lakeshore villages.  There is also Zege Peninsula on the southwest portion of the lake. Zege is the site of the Azwa Maryam monastery.

Water characteristics and floods.

Compared to other tropical lakes, the waters in Lake Tana are relatively cold, typically ranging from about. The water has a pH that is neutral to somewhat alkaline and its transparency is quite low.  Because of the large seasonal variations in the inflow of its tributaries, rain and evaporation, the water levels of Lake Tana typically vary by in a year, peaking in September–October just after the main wet season. When the water levels are high, the plains around the lake often are flooded and other permanent swamps in the region become connected to the lake.

Fauna.

Since there are no inflows that link the lake to other large waterways and the main outflow, the Blue Nile, is obstructed by the Blue Nile Falls, the lake supports a highly distinctive aquatic fauna, which generally is related to species from the Nile Basin. The lake's nutrient levels are low.

Fish.

There are 27 fish species in Lake Tana and 20 of these are endemic. This includes one of only two known cyprinid species flocks (the other, from Lake Lanao in the Philippines, has been decimated by introduced species). It consists of 15 relatively large, up to long, "Labeobarbus" barbs that formerly were included in "Barbus" instead. Among these, "L. acutirostris", "L. longissimus", "L. megastoma" and "L. truttiformis" are strictly piscivorous, and "L. dainellii", "L. gorguari", "L. macrophtalmus" and "L. platydorsus" are mostly piscivorous. Their most important prey are the small "Enteromius" and "Garra" species. The remaining "Labeobarbus" in Lake Tana have other specialized feeding habits: "L. beso" (non-endemic and not closely related to the others) feeds on algae, "L. surkis" mostly on macrophytes, "L. gorgorensis" on macrophytes and molluscs, "L. brevicephalus" on zooplankton (however, juveniles of all members of the species flock feed on zooplankton), "L. osseensis" on macrophytes and adults insects, and "L. crassibarbis", "L. intermedius" (non-endemic but closely related to the others), "L. nedgia" and "L. tsanensis" on benthic invertebrates like chironomid larvae. Among the endemic "Labeobarbus", eight species spawn in the lake's wetlands and the remaining move seasonally into its tributaries where they spawn.  In addition to the "Labeobarbus" species flock, the endemic species are "Enteromius pleurogramma", "E. tanapelagius", "Garra regressus", "G. regressus" and "Afronemacheilus abyssinicus" (one of only two African stone loaches). The remaining non-endemic species are Nile tilapia (widespread in Africa, but with the endemic subspecies "tana" in the lake), "E. humilis", "G. dembecha", "G. dembeensis" and the large African sharptooth catfish.

Fishing and threats.

Lake Tana supports a large fishing industry, mainly based on the "Labeobarbus" barbs, Nile tilapia and sharptooth catfish. According to the Ethiopian Department of Fisheries and Aquaculture, 1,454 tons of fish were landed in 2011 at Bahir Dar, which the department estimated was 15% of its sustainable amount. Nevertheless, in a review that compared catches in 2001 to those ten years earlier, it was found that typical sizes of both the tilapia and the catfish had significantly decreased, and populations of the "Labeobarbus" barbs that breed in the tributaries had significantly declined. Among the endemic fish, most are considered threatened (endangered or vulnerable) or data deficient (available data insufficient for evaluating a status) by the IUCN. In the early 2000s, the local government for the first time introduced a fisheries legislation and it is hoped this will have a positive effect on the fish populations.  Other serious threats are habitat destruction and pollution. Bahir Dar has become a large city and it is rapidly growing; its wastewater is generally released directly into the lake. The vegetation in the lake's wetlands, which are an important nursery for the "Labeobarbus" and other fish, are being cleared at a fast pace. A potentially serious threat to the unique ecosystem would be an introduction of a large and efficient predatory species like the Nile perch, which has been implicated in numerous extinctions in Lake Victoria. The piscivorous "Labeobarbus" of Lake Tana are relatively inefficient predators that only can take fish up to about 15% of the length of the predator itself.

Other fauna.

Among other fauna, the lake supports relatively few invertebrates: There are fifteen species of molluscs, including one endemic, and also an endemic freshwater sponge.  About 230 species of birds, including more than 80 wetland birds such as the great white pelican, African darter, hamerkop, storks, African spoonbill, ibis, ducks, kingfishers and African fish eagle, are known from Lake Tana. It is an important resting and feeding ground for many Palearctic migrant waterbirds.  There are no crocodiles, but the African softshell turtle has been recorded near the Blue Nile outflow from the lake. Hippos are present, mostly near the Blue Nile outflow.

Lake Tana (also spelled T'ana,, ', '; an older variant is Tsana, Ge'ez: ጻና "Ṣānā"; sometimes called "Dembiya" after the region to the north of the lake) is the source of the Blue Nile and is the largest lake in Ethiopia. Located in Amhara Region in the north-western Ethiopian Highlands, the lake is approximately long and wide, with a maximum depth of, and an elevation of. Lake Tana is fed by the Gilgel Abay, Reb and Gumara rivers. Its surface area ranges from, depending on season and rainfall. The lake level has been regulated since the construction of the control weir where the lake discharges into the Blue Nile. This controls the flow to the Blue Nile Falls (Tis Abbai) and hydro-power station.


Early years.

Weiss was born in present-day Poland, to Walenty S. Wojciechowski and Mary Bruszkiewicz. He had five siblings, Bernard, Frederick, Violet and Joseph, one of the two who died during infancy. He was nicknamed "Hymie" and "Hymie the Pole", later in his career. He was Catholic, despite the "Jewish-sounding" moniker (he carried a rosary and a bible). As a teenager, Weiss became a petty criminal. After he upset a fragrance shelf during a botched burglary as a youth, police dubbed him 'The Perfume Burglar'. He befriended the Irish-American Dean O'Banion. With Weiss and George "Bugs" Moran, O'Banion established the North Side Gang, a criminal organization that eventually controlled bootlegging and other illicit activities in the northern part of Chicago.

Personality.

When Weiss's brother Fred was questioned about him in 1926, he replied, "I've seen him once in twenty years... that was when he shot me, six years ago". When photographers tried to snap his picture, Weiss would glare at them and say in a low voice, "You take a picture of me and I'll kill you".  On one occasion, Weiss chased away at gunpoint by a deputy U.S. Marshal who came to arrest a friend for violation of the Mann Act at a party he was attending. The marshal returned with reinforcements, arrested the friend, and confiscated a cache of alcohol and weapons. After the raid, Weiss filed a lawsuit to recover silk shirts and socks that he claimed the marshals had stolen; both the government's charges and the lawsuit came to nothing.

Murder.

Jury selection for a murder trial of Joe Saltis, with whom Weiss sought an alliance, began on October 11, 1926 and Weiss and four of his men were sighted there. With him that day were his bodyguard Sam Pellar, gangster Paddy Murray, attorney William W. O'Brien, and Benjamin Jacobs (an investigator for O'Brien). At four o'clock that afternoon, Weiss and his men left for their State Street headquarters, Schofield’s Flowers. The quintet parked their cars on Superior Street and rounded the corner to cross State. As they did, two gunmen hidden in a nearby rooming house opened fire with a submachine gun and shotgun. Weiss and Murray were fatally wounded by this first burst. William O'Brien was hit four times and staggered into a nearby stairwell. At the initial sound of gunfire, a panicked Sam Pellar drew his.38 and instinctively fired a shot in the general direction of shooters (this bullet unintentionally struck Weiss as he collapsed onto the sidewalk). Pellar and Jacobs, both wounded, staggered back the way they had come. Bullets followed them the whole way and some chipped the cornerstone of the Holy Name Cathedral directly across the street.  Weiss is buried at Mount Carmel Cemetery in Hillside, Illinois, the same place as Al Capone and Dean O'Banion.

In popular culture.

Weiss and other Prohibition-era mobsters served as the basis for many gangster films of the 1930s. James Cagney, for example, based his character on both Weiss and Chicago gangland figure Dean O'Banion in "The Public Enemy" (1931).  In 2013 and 2014, Weiss is portrayed by Will Janowitz on the third and fourth seasons of "Boardwalk Empire".

Earl J. "Hymie" Weiss (born Henry Earl J. Wojciechowski; January 25, 1898 – October 11, 1926), was a Polish-American mob boss who became a leader of the Prohibition-era North Side Gang and a bitter rival of Al Capone. He was known as 'the only man Al Capone feared'.


History.

Named after Saint Stephen, the city first appears in the historical record in the Middle Ages as (after the River Furan, a tributary of the Loire). In the 13th century, it was a small borough around the church dedicated to Saint Etienne. On the upper reaches of the Furan, near the Way of St. James, the Abbey of Valbenoîte had been founded by the Cistercians in 1222. In the late 15th century, it was a fortified village defended by walls built around the original nucleus.  From the 16th century, Saint-Étienne developed an arms manufacturing industry and became a market town. It was this which accounted for the town's importance, although it also became a centre for the manufacture of ribbons and passementerie starting in the 17th century.  Later, it became a mining centre of the Loire coal mining basin, and more recently, has become known for its bicycle industry.  In the first half of the 19th century, it was only a chief town of an arrondissement in the'of the Loire, with a population of 33,064 in 1832. The concentration of industry prompted these numbers to rise rapidly to 110,000 by about 1880. It was this growing importance of Saint-Étienne that led to its being made seat of the prefecture and the departmental administration on 25 July 1855, when it became the chief town in the'and seat of the prefect, replacing Montbrison, which was reduced to the status of chief town of an. Saint-Étienne absorbed the commune of Valbenoîte and several other neighbouring localities on 31 March 1855.

Culture.

Saint-Étienne became a popular stop for automobile travelers in the early 20th century.  In 1998, Saint-Étienne set up a design biennale, the largest of its kind in France. It lasts around two weeks. A landmark in the history of the importance ascribed to design in Saint-Étienne was the inauguration of "La Cité du design" on the site of the former arms factory in 2009.  The city also launched the Massenet Festivals, (the composer Jules Massenet hailed from the area) devoted mainly to perform Massenet's operas. In 2000, the city was named one of the French Towns and Lands of Art and History. On 22 November 2010, it was nominated as "City of Design" as part of UNESCO’s Creative Cities Network.  Saint-Étienne has four museums:

Climate.

Saint-Étienne has a continental-influenced oceanic climate (Köppen climate classification: Cfb), that is heavily influenced by its relative distance to the sea. Summer days are very warm for a marine climate type, but fall into the range due to the cool nights that keep the mean average temperatures below the subtropical threshold of. Winters are cold. Saint-Étienne is the snowiest city of France, with an average of 82 cm (around 3 ft) of snow per winter. Precipitation levels are very low for this type of climate regime during winter, although the summers are wet and humid.

Sport.

The city's football club AS Saint-Étienne has won the Ligue 1 title a record ten times, achieving most of their success in the 1970s. The British indie-dance band Saint Etienne named themselves after the club.  St. Étienne has many sports stadiums, the largest being Stade Geoffroy-Guichard used for football and Stade Henri-Lux for athletics. St. Étienne was the capital of the French bicycle industry. The bicycle wheel manufacturer Mavic is based in the city and frame manufacturers Motobécane and Vitus are also based here. The city often hosts a stage of the Tour de France.  St. Étienne resident Thierry Gueorgiou is a world champion in orienteering. The local rugby union team is CA Saint-Étienne Loire Sud Rugby.

Transport.

The nearest airport is Saint-Étienne - Bouthéon Airport which is located in Andrézieux-Bouthéon, north-northwest of Saint-Étienne. The main railway station is Gare de Saint-Étienne-Châteaucreux, which offers high speed services to Paris, Lyon (Saint-Étienne–Lyon railway), and several regional lines.  Saint-Étienne is also notable for its tramway (Saint-Étienne tramway) – which uniquely with Lille, it kept throughout the 20th century – and its trolleybus system (Saint-Étienne trolleybus system) – which is one of only three such systems currently operating in France.  Bus and tram transport is regulated and provided by the Société de Transports de l'Agglomération Stéphanoise (STAS), a public transport executive organisation.  The bicycle sharing system Vélivert with 280 short term renting bicycles has been available since June 2010.

Notable people.

Saint-Étienne was the birthplace of  It was also the place where Andrei Kivilev died.

International relations.

Saint-Étienne is twinned with:

Saint-Étienne (;, ; ) is a city in eastern central France, in the Massif Central, southwest of Lyon in the Auvergne-Rhône-Alpes region, on the trunk road that connects Toulouse with Lyon. Saint-Étienne is the capital of the Loire department and has a population of approximately 172,023 (2013) in the city itself and over 508,000 in the metropolitan area (2011).


Plot summary.

The novel deals with the life of the Cossacks living in the Don River valley during the early 20th century, probably around 1912, just prior to World War I. The plot revolves around the Melekhov family of Tatarsk, who are descendants of a cossack who, to the horror of many, took a Turkish captive as a wife during the Crimean War. She is accused of witchcraft by Melekhov's superstitious neighbors, who attempt to kill her but are fought off by her husband. Their descendants, the son and grandsons, who are the protagonists of the story, are therefore often nicknamed "Turks". Nevertheless, they command a high level of respect among people in Tatarsk.  The second eldest son, Grigori Panteleevich Melekhov, is a promising young soldier who falls in love with Aksinia, the wife of Stepan Astakhov, a family friend. Stepan regularly beats her and there is no love between them. Grigori and Aksinia's romance and elopement raise a feud between her husband and his family. The outcome of this romance is the focus of the plot as well as the impending World and Civil Wars which draw up the best young Cossack men for what will be two of Russia's bloodiest wars. The action moves to the Austro-Hungarian front, where Grigory ends up saving Stepan's life, but that doesn't end the feud. Grigory, at his father's insistence, takes a wife, Natalya, but still loves Aksinia.  The book deals not only with the struggles and suffering of the Cossacks but also the landscape itself, which is vividly brought to life. There are also many folk songs referenced throughout the novel. "And Quiet Flows the Don" grew out of an earlier, unpublished work, the "Donshina":I began the novel by describing the event of the Kornilov putsch in 1917. Then it became clear that this putsch, and more importantly, the role of the Cossacks in these events, would not be understood without a Cossack prehistory, and so I began with the description of the life of the Don Cossacks just before the beginning of World War I. (quote from "M.A. Sholokhov: Seminarii", (1962) by F.A. Abramovic and V.V. Gura, quoted in "Mikhail Aleksandrovich Sholokhov", by L.L. Litus.)  Grigori Melekhov is reportedly based on two Cossacks from Veshenskaya, Pavel Nazarovich Kudinov and Kharlampii Vasilyevich Yermakov, who were key figures in the anti-Bolshevist struggle of the upper Don.

Literary significance, criticism, and accusations of plagiarism.

The novel has been compared to "War and Peace" (1869), written by Leo Tolstoy. Like the Tolstoy novel, "And Quiet Flows the Don" is an epic picture of Russian life during a time of crisis and examines it through political, military, romantic, and civilian lenses. Sholokhov was accused by Solzhenitsyn and others, amongst them Svetlana Alliluyeva (the daughter of Stalin) and Natalia Belinkova, of plagiarizing the novel. An investigation in the late 1920s had upheld Sholokhov's authorship of "Silent Don" and the allegations were denounced as malicious slander in "Pravda".  During the Second World War, Sholokhov's archive was destroyed in a bomb raid, and only the fourth volume survived. Sholokhov had his friend Vassily Kudashov, who was killed in the war, look after it. Following Kudashov's death, his widow took possession of the manuscript, but she never disclosed the fact of owning it. The manuscript was finally found by the Institute of World Literature of Russian Academy of Sciences in 1999 with assistance from the Russian Government. The writing paper dates back to the 1920s: 605 pages are in Sholokhov's own hand, evidencing considerable re-drafting and re-organising of the material by Sholokhov, and 285 are transcribed by his wife Maria and sisters. However, there are claims that the manuscript is just a copy of the manuscript of Fyodor Kryukov, the true author.  Statistical analysis of sentence lengths in "And Quiet Flows the Don" gives full support to Sholokhov.

Awards and nominations.

The novel won the Stalin Prize in 1941 and its author won the Nobel Prize in 1965.

Adaptations.

The novel has been adapted for the screen four times: a 1931 film by Ivan Pravov and Olga Preobrazhenskaya; a second, 1958 adaption was directed by Sergei Gerasimov and starred Elina Bystritskaya and Pyotr Glebov. In 1992–1993 a remake was directed by Sergei Bondarchuk (starring Rupert Everett); the film was not finished until 2006, when Fyodor Bondarchuk completed the editing, and was shown on Russian television as a seven-part miniseries. A shorter, 3-hours version of Bondarchuk's "And Quiet Flows the Don" was released on DVD in several countries. In 2015 the novel has been adapted again more comprehensively as a 14-part TV-series, directed by Sergey Ursulyak.  Ivan Dzerzhinsky based his opera "Quiet Flows the Don" ("Tikhiy Don") on the novel, with the libretto adapted by his brother Leonid. Premiered in October 1935, it became wildly popular after Stalin saw and praised it a few months later. The opera was proclaimed a model of socialist realism in music and won Dzerzhinsky a Stalin Prize.  The lyrics for the folk song "Where Have All the Flowers Gone?" by Pete Seeger and Joe Hickerson were adapted from a cossack folk song mentioned in "And Quiet Flows the Don".

And Quiet Flows the Don or Quietly Flows the Don (, literally "Quiet Don") is an epic novel in four volumes by Russian writer Mikhail Alexandrovich Sholokhov. The first three volumes were written from 1925 to 1932 and published in the Soviet magazine "Oktyabr" in 1928–1932, and the fourth volume was finished in 1940. The English translation of the first three volumes appeared under this title in 1934.


Description.

Convolvulaceae can be recognized by their funnel-shaped, radially symmetrical corolla; the floral formula for the family has five sepals, five fused petals, five epipetalous stamens (stamens fused to the petals), and a two-part syncarpous and superior gynoecium. The stems of these plants are usually winding, hence their Latin name (from "convolvere", "to wind"). The leaves are simple and alternate, without stipules. In parasitic Cuscuta they are reduced to scales. The fruit can be a capsule, berry, or nut, all containing only two seeds per one locule (one ovule/ovary). The leaves and starchy, tuberous roots of some species are used as foodstuffs (e.g. sweet potato and water spinach), and the seeds are exploited for their medicinal value as purgatives. Some species contain ergoline alkaloids that are likely responsible for the use of these species as ingredients in psychedelic drugs (e.g. ololiuhqui). The presence of ergolines in some species of this family is due to infection by fungi related to the ergot fungi of the genus "Claviceps". A recent study of Convolvulaceae species, "Ipomoea asarifolia", and its associated fungi showed the presence of a fungus, identified by DNA sequencing of 18s and ITS ribosomal DNA and phylogenetic analysis to be closely related to fungi in the family Clavicipitaceae, was always associated with the presence of ergoline alkaloids in the plant. The identified fungus appears to be a seed-transmitted, obligate biotroph growing epiphytically on its host. This finding strongly suggests the unique presence of ergoline alkaloids in some species of the family Convolvulaceae is due to symbiosis with clavicipitaceous fungi. Moreover, another group of compounds, loline alkaloids, commonly produced by some members of the clavicipitaceous fungi (genus "Neotyphodium"), has been identified in a convolvulaceous species, but the origin of the loline alkaloids in this species is unknown.  Members of the family are well known as showy garden plants (e.g. morning glory) and as troublesome weeds (e.g. bindweed and dodder), while "Humbertia madagascariensis" is a medium-sized tree. Some parasitic members of this family are also used medicinally.

Convolvulaceae (), known commonly as the bindweed or morning glory family, is a family of about 60 genera and more than 1,650 species of mostly herbaceous vines, but also trees, shrubs and herbs, and also including the sweet potato and a few other food tubers.


Early years.

Colosimo was born on February 16, 1878, to Luigi Colosimo and his second wife Giuseppina Mascaro in the town of Colosimi, Province of Cosenza, Italy. He emigrated from Italy to Chicago at the age of 17, starting out as a petty criminal. Colosimo attracted the attention of First Ward aldermen Michael "Hinky Dink" Kenna and John Coughlin. They made him a precinct captain and later their bagman. This gave Colosimo the political connections that helped him in his rise to power as a mob boss.

Prostitution empire.

Later, Colosimo acquired another nickname, "Diamond Jim," because he frequently dressed in a white suit and wore diamond pins, rings, and other jewelry. This, combined with his personal charm and money, helped him establish relationships with women. He had a love of both women and money, which fueled his enthusiasm for prostitution. In 1902, Colosimo married Victoria Moresco, an established Chicago madame, and together they opened a second brothel. Torrio was the nephew of Moresco. According to Laurence Bergreen, "Torrio is [also] described as Colosimo’s nephew, but in the absence of any evidence to confirm the relationship, it is more likely their kinship was spiritual rather than familial." Within a few years, Colosimo had expanded this to nearly 200 brothels and had also made inroads into gambling and racketeering. He was reputedly making $50,000 per month from his various legal and illegal operations.

Help from New York.

By 1909, Black Hand extortion was a serious threat to Colosimo in Chicago. He brought in gangster John "The Fox" Torrio from Brooklyn and made him his second in command. The following year, he opened Colosimo's Cafe, a restaurant and nightclub at 2126 South Wabash. It quickly became a popular destination for prominent Chicagoans and visitors to Chicago. In 1919, Torrio and Colosimo opened a brothel at 2222 South Wabash called the Four Deuces, a reference to the address. Torrio hired his old Brooklyn colleague Al Capone to work as a bartender and bouncer, which gave Capone his entry into Chicago crime.

Betrayal.

When Prohibition went into effect in 1920, Torrio pushed for the gang to enter into bootlegging, but Colosimo stubbornly refused. In March 1920, Colosimo secured an uncontested divorce from Moresco. A month later, he and Dale Winter eloped to West Baden Springs, Indiana. Upon their return, he bought a home on the South Side. On May 11, 1920, Torrio called and told Colosimo that a shipment was about to arrive at his restaurant. Colosimo drove there to await it, but instead he was shot in an ambush and killed. Frankie Yale had allegedly traveled from New York to Chicago and personally killed longtime gang boss Colosimo at the behest of Chicago Outfit friends Torrio and Capone. Although suspected by Chicago police, Yale was never officially charged. Colosimo was allegedly murdered because he stood in the way of his gang making bootlegging profits, having "gone soft" after his marriage with Winter. Al Capone has also been suggested as the gunman. Colosimo's ex-wife, unhappy with the financial arrangements of the divorce, is also theorized having arranged the murder.  Colosimo was the first gang leader to organize the disparate parts of Chicago's crime scene. After his death, Torrio took over his gang, later to be replaced by Al Capone. His mob eventually became the infamous Chicago Outfit that ruled over some parts of the city.

In popular media.

Big Jim has been portrayed on screen by:

Vincenzo Colosimo (; February 16, 1878 – May 11, 1920), known as James "Big Jim" Colosimo or as "Diamond Jim", was an Italian-American Mafia crime boss who emigrated from Calabria, Italy, in 1895, and built a criminal empire in Chicago based on prostitution, gambling, and racketeering. He gained power through petty crime and by heading a chain of brothels. From about 1902 until his death in 1920, he led a gang that became known after his death as the Chicago Outfit. Johnny Torrio was an enforcer whom Colosimo imported in 1909 from New York and who seized control after his death. Al Capone, a Torrio henchman, allegedly was directly involved in the murder.


Taxonomy.

The vaquita was first described as a species by marine biologists Kenneth S. Norris and William N. McFarland in 1958 after studying the morphology of skull specimens found on the beach. It was not until nearly thirty years later, in 1985, that fresh specimens allowed scientists to describe their external appearance fully.  The genus "Phocoena" comprises four species of porpoise, most of which inhabit coastal waters (the spectacled porpoise is more oceanic). The vaquita is most closely related to Burmeister’s porpoise ("Phocoena spinipinnis") and less so to the spectacled porpoise ("Phocoena dioptrica"), two species limited to the Southern Hemisphere. Their ancestors are thought to have moved north across the equator more than 2.5 million years ago during a period of cooling in the Pleistocene.

Description.

The smallest living species of cetacean, the vaquita can be easily distinguished from any other species in its range. It has a small body with an unusually tall, triangular dorsal fin, a rounded head, and no distinguished beak. The coloration is mostly grey with a darker back and a white ventral field. Prominent black patches surround its lips and eyes. Sexual dimorphism is apparent in body size, with mature females being longer than males and having larger heads and wider flippers. Females reach a maximum size of about 150 cm, while males reach about 140 cm. Dorsal fin height is greater in males than in females.

Distribution and habitat.

Vaquita habitat is restricted to a small portion of the upper Gulf of California (also called the Sea of Cortez), making this the smallest range of any marine mammal species. They live in shallow, turbid waters of less than 50 m depth (150 ft).

Diet.

Vaquitas are generalists, foraging on a variety of demersal fish species, crustaceans, and squids, though benthic fish such as grunts and croakers make up most of the diet.

Social behavior.

Vaquitas are generally seen singly or in pairs, often with a calf, but have been observed in small groups of up to 10 individuals.  Little is known about the life history of this species. Life expectancy is estimated at about 20 years and age of sexual maturity is somewhere between 3 and 6 years of age. While an initial analysis of stranded vaquitas estimated a two-year calving interval, recent sightings data suggest that vaquitas can reproduce annually. It is thought that vaquitas have a polygynous mating system in which males compete for females. This competition is evidenced by the presence of sexual dimorphism (females are larger than males), small group sizes, and large testes (accounting for nearly 3% of body mass).

Population status.

Because the vaquita was only fully described in the late 1980s, historical abundance is unknown. The first comprehensive vaquita survey throughout their range took place in 1997 and estimated a population of 567 individuals. By 2007 abundance was estimated to have dropped to 150. Population abundance as of 2018 was estimated at less than 19 individuals. Given the continued rate of bycatch and low reproductive output from a small population, it is possible that there are as few as 10 vaquitas alive today.

Threats.

Fisheries bycatch.

The drastic decline in vaquita abundance is the result of fisheries bycatch in commercial and illegal gillnets, including fisheries targeting the now-endangered totoaba, shrimp, and other available fish species. In spite of government regulations, including a partial gillnet ban in 2015 and establishment of a permanent gillnet exclusion zone in 2017, illegal fishing remains prevalent in vaquita habitat, and as a result the population has continued to decline.

Other threats.

Given their proximity to the coast, vaquitas are exposed to habitat alteration and pollution from runoff. There is no evidence, however, that these threats have made any significant contribution to their decline. Bycatch is the single biggest threat to the survival of the few remaining vaquita.

Conservation status.

The vaquita is listed as critically endangered on the IUCN Red List. Today, this is the most endangered marine mammal in the world.  The species is also protected under the US Endangered Species Act, the Mexican Official Standard NOM-059 (Norma Oficial Mexicana), and Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

Conservation efforts.

The Mexican government, international committees, scientists, and conservation groups have recommended and implemented plans to help reduce the rate of bycatch, enforce gillnet bans, and promote population recovery.  Mexico launched a program in 2008 called PACE-VAQUITA in an effort to enforce the gillnet ban in the Biosphere Reserve, allow fishermen to swap their gillnets for vaquita-safe fishing gear, and provide economic support to fishermen for surrendering fishing permits and pursuing alternative livelihoods. Despite the progress made with legal fishermen, hundreds of poachers continued to fish in the exclusion zone.  With continued illegal totoaba fishing and uncontrolled bycatch of vaquitas, the International Committee for the Recovery of the Vaquita (CIRVA) recommended that some vaquitas be removed from the high-density fishing area and be relocated to protected sea pens. This effort, called VaquitaCPR, captured two vaquitas in 2017: one was later released and the other died shortly after capture after both suffered from shock.  Local and international conservation groups, including Museo de Ballena and Sea Shepherd Conservation Society, are working with the Mexican Navy to detect fishing in the Refuge Area and remove illegal gillnets. In March 2020, the U.S. National Marine Fisheries Service (NMFS) announced a ban on imported Mexican shrimp and other seafood caught in vaquita habitat in the northern Gulf of California.  To date, efforts have been unsuccessful in solving the complex socioeconomic and environmental issues that impact vaquita conservation and the greater Gulf of California ecosystem. Necessary action includes habitat protection, resource management, education, fisheries enforcement, alternative livelihoods for fishermen, and raising awareness of the vaquita and associated issues.

External links.

To learn more about the vaquita and conservation efforts visit:

The vaquita ("Phocoena sinus") is a species of porpoise endemic to the northern end of the Gulf of California (Sea of Cortez, Vermilion Sea). Averaging 150 cm (for females) or 140 cm (for males) in length, it is the smallest of all living cetaceans. Today, the species is on the brink of extinction. Recent research estimates the population at fewer than 19 individuals. The steep decline in abundance is primarily due to bycatch in gillnets from the illegal totoaba fishery.


Use by humans.

Bitter vetch ("V. ervilia") was one of the first domesticated crops. It was grown in the Near East about 9,500 years ago, starting perhaps even one or two millennia earlier during the Pre-Pottery Neolithic A. By the time of the Central European Linear Pottery culture – about 7,000 years ago – broad bean ("V. faba") had also been domesticated. Vetch has been found at Neolithic and Eneolithic sites in Bulgaria, Hungary and Slovakia. And at the same time, at the opposite end of Eurasia, the Hoabinhian people also utilized the broad bean in their path towards agriculture, as shown by the seeds found in Spirit Cave, Thailand.  Bernard of Clairvaux shared a bread-of-vetch meal with his monks during the famine of 1124 to 1126, as an emblem of humility. However, Bitter Vetch largely was dropped from human use over time. It was only used to save as a crop of last resort in times of starvation: vetches "featured in the frugal diet of the poor until the eighteenth century, and even reappeared on the black market in the South of France during the Second World War", Maguelonne Toussaint-Samat, of Marseillais background, has remarked. However, broad beans remained prominent. In the Near East the seeds are mentioned in Hittite and Ancient Egyptian sources dating from more than 3,000 years ago as well as in the Christian Bible, and in the large Celtic Oppidum of Manching from the La Tène culture in Europe some 2,200 years ago. Dishes resembling ful medames are attested in the Jerusalem Talmud which was compiled before 400 AD.  In our time, the common vetch ("V. sativa") has also risen to prominence. Together with broad bean cultivars such as horse bean or field bean, the FAO includes it among the 11 most important pulses in the world. The main usage of the common vetch is as forage for ruminant animals, both as fodder and legume, but there are other uses, as tufted vetch, "V. cracca" is grown as a mid-summer pollen source for honeybees.  In 2017, global production of vetches was 920,537 tonnes. That year, 560,077 acreas were devoted to the cultivation of vetches in the world. Over 54% of that output came from Europe alone. Africa (17.8% of world total), Asia (15.6% of world total), Americas (10.6% of world total) and Oceania (1.8% of world total).  The bitter vetch, too, is grown extensively for forage and fodder, as are hairy vetch ("V. villosa", also called fodder vetch), bard vetch ("V. articulata"), French vetch ("V. serratifolia") and Narbon bean ("V. narbonensis"). "V. benghalensis" and Hungarian vetch ("V. pannonica") are cultivated for forage and green manure. The vetches also have a broad variety of other purposes. The Hairy Vetch has well-established uses as a green manure and as an allelopathic cover crop. As regards the broad bean, it is known to accumulate aluminum in its tissue; in polluted soils it may be useful in phytoremediation, but with one per mil of aluminum in the dry plant (possibly more in the seeds), it might not be edible anymore. The robust plants are useful as a beetle bank to provide habitat and shelter for carnivorous beetles and other arthropods to keep down pest invertebrates. When the root nodules of broad bean are inoculated with the rhodospirillacean bacterium "Azospirillum brasilense" and the glomeracean fungus "Glomus clarum", the species can also be productively grown in salty soils. In the 1980s, the auxin 4-Cl-IAA was studied in "V. amurensis" and the broad bean, and since 1990, the antibacterial γ-thionins fabatin-1 and -2 have been isolated from the latter species.  Despite a small chromosome count of "n"=6, the broad bean has a high DNA content, making it easy for a micronucleus test of its root tips to recognize genotoxic compounds. A lectin from "V. graminea" is used to test for the medically significant N blood group.

Toxicity.

The vetches grown as forage are generally toxic to non-ruminants (such as humans), at least if eaten in quantity. Cattle and horses have been poisoned by "V. villosa" and "V. benghalensis", two species that contain canavanine in their seeds. Canavanine, a toxic analogue of the amino acid arginine, has been identified in Hairy Vetch as an appetite suppressant for monogastric animals, while Narbon bean contains the quicker-acting but weaker γ-glutamyl-S-ethenylcysteine. In common vetch, γ-glutamyl-β-cyanoalanine has been found. The active part of this molecule is β-cyanoalanine. It inhibits the conversion of the sulfur amino acid methionine to cysteine.  Cystathionine, an intermediary product of this biochemical pathway, is secreted in urine. This process can effectively lead to the depletion of vital protective reserves of the sulfur amino acid cysteine and thereby making "Vicia sativa" seed a dangerous component in mixture with other toxin sources. The Spanish pulse mix "" contains common vetch and bitter vetch in addition to vetchling ("Lathyrus cicera") seeds; it can be fed in small quantities to ruminants, but its use as a staple food will cause lathyrism even in these animals. Moreover, common vetch as well as broad bean – and probably other species of "Vicia" too – contain oxidants like convicine, isouramil, divicine and vicine in quantities sufficient to lower glutathione levels in G6PD-deficient persons to cause favism disease. At least broad beans also contain the lectin phytohemagglutinin and are somewhat poisonous if eaten raw. Split common vetch seeds resemble split red lentils ("Lens culinaris"), and has been occasionally mislabelled as such by exporters or importers to be sold for human consumption. In some countries where lentils are highly popular – e.g., Bangladesh, Egypt, India and Pakistan – import bans on suspect produce have been established to prevent these potentially harmful scams.

Ecology.

Vetches have cylindrical root nodules of the indeterminate type and are thus nitrogen-fixing plants. Their flowers usually have white to purple or blue hues, but may be red or yellow; they are pollinated by bumblebees, honey bees, solitary bees and other insects.  "Vicia" species are used as food plants by the caterpillars of some butterflies and moths, such as:  Most other parasites and plant pathogens affecting vetches have been recorded on the broad bean, the most widely cultivated and economically significant species. They include the mite "Balaustium vignae" whose adults are found on broad bean, the potexviruses "Alternanthera" mosaic virus, clover yellow mosaic virus and white clover mosaic virus, and several other virus species such as "Bidens" mosaic virus, tobacco streak virus, "Vicia" cryptic virus and "Vicia faba" endornavirus.  Plants formerly placed in "Vicia" include:

Etymology.

"Vicia" means ‘binder’ in Latin; this was the name used by Pliny for vetch.  The vetch is also referenced by Horace in his account of 'The town mouse and country mouse' as 'ervo' (ervum,i - neut) This is said to be a source of comfort for the country mouse after a disturbing insight into urban life.

Vicia is a genus of about 140 species of flowering plants that are part of the legume family (Fabaceae), and which are commonly known as vetches. Member species are native to Europe, North America, South America, Asia and Africa. Some other genera of their subfamily Faboideae also have names containing "vetch", for example the vetchlings ("Lathyrus") or the milk-vetches ("Astragalus"). The broad bean ("Vicia faba") is sometimes separated in a monotypic genus "Faba"; although not often used today, it is of historical importance in plant taxonomy as the namesake of the order Fabales, the Fabaceae and the Faboideae. The tribe Vicieae in which the vetches are placed is named after the genus' current name. Among the closest living relatives of vetches are the lentils ("Lens") and the true peas ("Pisum").


History.

Domažlice was first recorded as a town in 1231, when Přemysl Otakar II of Bohemia ordered the city to be fortified for the purpose of protecting the border with Bavaria. It would remain fortified from 1262 to 1265. Border guards were recruited from the Chodové (Slavic free farmers) who settled in the vicinity of Domažlice.  The city was mortgaged to Bavaria in 1331, lasting until 1419 (with some interruptions). Under Hussite rule, German citizens were expelled from the city, and since then, the population has been predominantly Czech. In 1431, Prokop the Bald defeated the crusaders of the Holy Roman Empire near Domažlice. The 15th and 16th century saw Domažlice change hands frequently, but its importance diminished following the end of the Thirty Years' War. It was not until 1770 that it recovered, largely due to innovations in the textile industry.  Until 1918 the town was part of the Austrian monarchy, finding itself on the Austrian side of the Austro-Hungarian internal frontier following the 1867 "Ausgleich" "(compromise)". It was the district capital of the district with the same name, being one of the 94 "Bezirkshauptmannschaften" (district capitals) in Bohemia.  Within the context of the Czech National Revival, Domažlice became a central place during the 19th century. At the time, it was the most western ethnic Czech town, very close to the border with the Kingdom of Bavaria. In the city, a pilgrimage took place on August 13, 1939, which developed into a large Czech protest demonstration against the German occupation and control of the ethnic Czech Protectorate of Bohemia and Moravia.The German population was expelled in 1945 according to the Potsdam Agreement.  In 2005 a mass grave was discovered on the outskirts of the town, holding 54 Germans, mainly members of the local SA, executed by the Czech resistance after the end of the war, around May 8, 1945.

Twin towns — sister cities.

Domažlice is twinned with:

Domažlice (; ) is a town in the Plzeň Region of the Czech Republic. Domažlice is also a Municipality with Extended Competence and a Municipality with Commissioned Local Authority within the same borders.


History.

The first written mention of the town is in 1220. Before that, it was probably a Slavic settlement. At the end of the 12th century more people arrived. At the beginning of the 13th century a Gothic castle was built (it was gradually rebuilt into a Renaissance chateau in the 16th century). In the census following the Thirty Years' War, Jindřichův Hradec was the second largest city in the Kingdom of Bohemia. Between 1831 and 1935 it was the first city in the area to get electricity for lighting, in 1888 the water mill was converted to electricity.

Main sights.

The city castle and palace is the third largest in the country after those in Prague and Český Krumlov. It covers and contains 320 rooms. More than 10,000 works of art and a similar number of books may be found there.  The district museum, which is in a Renaissance building that was once the Jesuit seminary appeared in the city in 1882 and is one of the oldest regional museums in Bohemia. The most well-known item in the museum is the Kryza, the largest mechanical Christmas manger scene in the world according to the Guinness Book of World Records.  Houses in the marketplace (Friendensplatz) with the pristine Gothic city hall

Surroundings.

Jindřichův Hradec's neighbourhood includes sites such as Červená Lhota Castle, the historical town of Třeboň and Stráž nad Nežárkou. The UNESCO World Heritage town of Telč lies to the east.

Twin towns — sister cities.

Jindřichův Hradec is twinned with:

Jindřichův Hradec (; ) is a town in the South Bohemian Region of the Czech Republic. It has approximately 21,500 inhabitants and is the capital of the Jindřichův Hradec District.


Overview.

Moodle was originally developed by Martin Dougiamas to help educators create online courses with a focus on interaction and collaborative construction of content, and it is in continual evolution. The first version of Moodle was released on 20 August 2002. Nowadays the Moodle Project is led and coordinated by Moodle HQ, an Australian company of 50 developers which is financially supported by a network of eighty-four Moodle Partner service companies worldwide. Moodle's development has also been assisted by the work of open-source programmers.  Moodle as a learning platform can enhance existing learning environments. As an E-learning tool, Moodle has a wide range of standard and innovative features such as a calendar and a Gradebook. Moodle is a leading virtual learning environment and can be used in many types of environments such as education, training and development and in business settings.

Plugins.

Plugins are a flexible tool set, allowing Moodle users to extend the features of the site. There are hundreds of plugins for Moodle, extending the features of Moodle's core functionality. Each plugin is maintained in the Moodle plugins directory. As of October 2019, there were 1,619 plugins available for Moodle with over 380,400 recent downloads.

Themes.

Graphical themes for Moodle can be installed to change the look and functionality of a Moodle site or of an individual course.

Mobile.

Many Moodle themes, based on responsive web design, allow Moodle to be used on mobile devices. Also, a Moodle mobile app is available in Google Play, App Store (iOS), and the Windows Phone Store.

E-learning standards support.

Moodle has adopted the following e-learning standards:

Deployment.

Users can download and install Moodle on a Web server, such as Apache HTTP Server, and a number of database management systems, such as MySQL, are supported. Pre-built combinations of Moodle with a Web server and database are available for Microsoft Windows and Macintosh. Other automated installation approaches exist, such as installing a Debian package, deploying a ready-to-use TurnKey Moodle appliance, using the Bitnami installer, or using a "one-click install" service such as Installatron.  Certified Moodle Partners provide other Moodle services, including hosting, training, customization and content development. This network of providers support development of the Moodle project through royalties.

Interoperability.

Moodle runs without modification on Unix, Linux, FreeBSD, Windows, OS X, NetWare and any other systems that support PHP and a database, including webhost providers.  Moodle also has import features for use with other specific systems, such as importing quizzes or entire courses from Blackboard or WebCT., Moodle did not import Blackboard courses, apparently due to changes in php code-releases.  In March 2012 Blackboard acquired two companies based on Moodle's software including Baltimore-based Moodlerooms Inc. and NetSpot of Adelaide, Australia. In August 2015, Blackboard acquired Colombia-based Nivel7, possibly the largest Moodle services provider in Latin America. The Red Hat site, Opensource.com, reported that Moodle will always be an open-source project, with clear delineation between Blackboard and Moodle.

Background.

Origins.

Martin Dougiamas, who has graduate degrees in computer science and education, wrote the first version of Moodle. Dougiamas started a Ph.D. to examine "the use of open source software to support a social constructionist epistemology of teaching and learning within Internet-based communities of reflective inquiry." Although how exactly social constructivism makes Moodle different from other eLearning platforms is difficult to show, it has been cited as an important factor by Moodle adopters. Other Moodle adopters, such as the Open University in the UK, have pointed out that Learning Management Systems can equally be seen as "relatively pedagogy-neutral".

Pedagogical approach.

The stated philosophy of Moodle includes a constructivist and social constructionist approach to education, emphasizing that learners (and not just teachers) can contribute to the educational experience. Using these pedagogical principles, Moodle provides an environment for learning communities.

Origin of name.

The acronym "Moodle" stands for "modular object-oriented dynamic learning environment." (In the early years the "m" stood for "Martin's", named after Martin Dougiamas, the original developer). As well as being an acronym, the name was chosen because of the dictionary definition of Moodle and to correspond to an available domain name.

Development.

Moodle has continued to evolve since 1999 (since 2001 with the current architecture). It has been translated into over 100 different languages and is accessible in many countries worldwide. Institutions can add as many Moodle servers as needed without having to pay license fees. The Open University of the UK currently uses a Moodle installation for their 200,000 users while the UK government uses a Moodle installation for their Civil Service Learning platform serving half a million employees.

Moodle conferences.

A MoodleMoot is a conference for Moodle community members, held to learn about Moodle, share experiences of the learning platform, discuss research in related educational technologies and contribute ideas to future Moodle development. Held around the world, MoodleMoots are organised by universities or other large organisations using Moodle, Moodle Partners, Moodle associations or Moodle HQ.

Adoption.

Moodle has over 50% of market share in Europe, Latin America, and Oceania.  In the U.S. higher education market as of fall 2018, the top three LMSs by number of institutions were Blackboard (31%), Canvas (30%), and Moodle (18%). --- In 2013, Moodle was for a time the second largest provider with 23% market share (following Blackboard (41%). However, by 2017, Moodle had dropped to the third largest provider, due in part to increased adoption of Instructure's semi-opensource Canvas platform. In March 2016, Blackboard became an official Moodle partner, although this was later completely revoked.

Moodle is a free and open-source learning management system (LMS) written in PHP and distributed under the GNU General Public License. Developed on pedagogical principles, Moodle is used for blended learning, distance education, flipped classroom and other e-learning projects in schools, universities, workplaces and other sectors.


Description.

The leaves of "A. maculatum" appear in the spring (April–May) followed by the flowers borne on a poker-shaped inflorescence called a "spadix", which is partially enclosed in a pale green spathe or leaf-like hood. The flowers are hidden from sight, clustered at the base of the spadix with a ring of female flowers at the bottom and a ring of male flowers above them. The leaves may be either purple-spotted (var. "maculatum") or unspotted (var. "immaculatum").  Above the male flowers is a ring of hairs forming an insect trap. Insects, especially owl-midges "Psychoda phalaenoides", are attracted to the spadix by its faecal odour and a temperature up to 15 °C warmer than the ambient temperature. The insects are trapped beneath the ring of hairs and are dusted with pollen by the male flowers before escaping and carrying the pollen to the spadices of other plants, where they pollinate the female flowers. The spadix may also be yellow, but purple is the more common.  In autumn, the lower ring of (female) flowers forms a cluster of bright red berries which remain after the spathe and other leaves have withered away. These attractive red to orange berries are extremely poisonous. The berries contain oxalates of saponins which have needle-shaped crystals that irritate the skin, mouth, tongue, and throat, and result in swelling of throat, difficulty breathing, burning pain, and upset stomach. However, their acrid taste, coupled with the almost immediate tingling sensation in the mouth when consumed, means that large amounts are rarely taken and serious harm is unusual. It is one of the most common causes of accidental plant poisoning based on attendance at hospital emergency departments.  The root-tuber may be very big and is used to store starch. In mature specimens, the tuber may be as much as 400 mm below ground level. All parts of the plant can produce allergic reactions in many people and the plant should be handled with care. Many small rodents appear to find the spadix particularly attractive; finding examples of the plant with much of the spadix eaten away is common. The spadix produces heat and probably scent as the flowers mature, and this may attract the rodents.  "Arum maculatum" is also known as cuckoo pint or cuckoo-pint in the British Isles and is named thus in Nicholas Culpepers' famous 17th-century herbal. This is a name it shares with "Arum italicum" (Italian lords-and-ladies) - the other native British "Arum". "Pint" is a shortening of the word "pintle", meaning penis, derived from the shape of the spadix. The euphemistic shortening has been traced to Turner in 1551.  As a seedling the plant has small light green leaves that are not glossy like the mature leaves. At about 5 months its leaves grow larger and glossier. At one year old all of the leaves become glossy and die back. The next year the plant flowers during summer.

Habitat.

It grows in woodland areas and riversides. It can occasionally grow as a weed in partly shaded spots.

Taxonomy.

"A. maculatum" is the type species of the genus "Arum". Within the genus, it belongs to subgenus "Arum", section "Arum".  "A. maculatum" has a chromosome count of 2n = 56.

Uses.

Culinary.

The root of the cuckoo-pint, when roasted well, is edible and when ground was once traded under the name of Portland sago. It was used like salep (orchid flour) to make saloop — a drink popular before the introduction of tea or coffee. It was also used as a substitute for arrowroot. If prepared incorrectly, it can be highly toxic, so should be prepared with due diligence and caution.

Cultivated.

"Arum maculatum" is cultivated as an ornamental plant in traditional and woodland shade gardens. The cluster of bright red berries standing alone without foliage can be a striking landscape accent. The mottled and variegated leaf patterns can add bright interest in darker habitats.  "Arum maculatum" may hybridize with "Arum italicum".

Laundry starch.

In 1440, the nuns of Syon Abbey in England used the roots of the cuckoo-pint flower to make starch for altar cloths and other church linens. In fact, communion linen could only be made in this way.

Arum maculatum is a common woodland plant species of the family Araceae. It is widespread across most of Europe, as well as Turkey and the Caucasus. It is known by an abundance of common names including snakeshead, adder's root, arum, wild arum, arum lily, lords-and-ladies, devils and angels, cows and bulls, cuckoo-pint, soldiers diddies, priest's pintle, Adam and Eve, bobbins, naked girls, naked boys, starch-root, wake robin, friar's cowl, sonsie-give-us-your-hand, jack in the pulpit and cheese and toast. The name "lords-and-ladies" and other gender-related names refer to the plant's likeness to male and female genitalia symbolising copulation.


History.

The South Orkney Islands were discovered in 1821 by two sealers, the American Nathaniel Brown Palmer and the British George Powell. The Islands were originally named "Powell's Group", with the main island named Coronation Island as it was the year of the coronation of King George IV. In 1823, James Weddell visited the Islands, gave the archipelago its present name (after the Orkney Islands in the north of Scotland) and also renamed some of the islands. The South Orkney Islands are located at roughly the same latitude south as the Orkney Islands are north (60°S vs 59°N), although it is not known if this was a factor behind the naming of the islands.  Subsequently, the islands were frequently visited by sealers and whalers, but no thorough survey was done until the expedition of William Speirs Bruce on the "Scotia" in 1903, which overwintered at Laurie Island. Bruce surveyed the islands, reverted some of Weddell's name changes, and established a meteorological station, which was sold to the Argentine Government upon his departure in 1904. This base, renamed "Orcadas" in 1951, is still in operation and is thus the oldest research station continuously staffed in the Antarctic.  In 1908, the United Kingdom declared sovereignty over various Antarctic and South American territories "to the south of the 50th parallel of south latitude, and lying between the 20th and the 80th degrees of west longitude", including the South Orkney Islands. The Islands were subsequently administered as part of the Falkland Islands Dependencies. A biological research station on Signy Island was built in 1947 by the British Antarctic Survey, and was staffed year-round until 1996, when the Station staffing was reduced to 8-10 personnel who remained only during the southern hemisphere summer (November to April each year). In 1962, the islands became part of the newly established British Antarctic Territory.  The Argentine claim to the islands dates from 1925. It was originally justified by the Argentine occupation of the Laurie Island base and later subsumed into a wider territorial claim.

Geography and climate.

The islands are situated at latitudes about 60°30' to 60°48' S and longitudes 44°25' to 46°43' W in the Southern Ocean. As a group of islands, the South Orkney Islands are at approximately.  The archipelago comprises four main islands. Coronation Island is the largest, measuring about long; its highest point is Mount Nivea which rises to above sea level. Laurie Island is the easternmost of the islands. The other main islands are Powell and Signy. Smaller islands in the group include Robertson Islands, the Saddle Islands, and Acuña Island. The total area of the archipelago is about, of which about 90 percent is glaciated.  The Inaccessible Islands about to the west are considered part of the South Orkneys.  The climate of the South Orkneys is generally cold, wet, and windy. Summers are short and cold (December to March) when the average temperatures reach about and fall to about in July. The all time temperature range is between. The seas around the islands are ice-covered from late April to November.  South Orkney Trough () is an undersea trough named in association with the South Orkney Islands and approved 10/77 (ACUF 177).

Flora and fauna.

Despite the harsh conditions the islands do support vegetation and are part of the Scotia Sea Islands tundra ecoregion, along with South Georgia and the South Sandwich Islands, the South Shetland Islands and Bouvet Island. All these islands lie in the cold seas below the Antarctic convergence. These areas support tundra vegetation consisting of mosses, lichens and algae, while seabirds, penguins and seals feed in the surrounding waters.  The littoral zone of the South Orkneys is biologically either lifeless or very poor. Amphipods and planarians exist under rocks, along with various algaes, chitons, and some gastropods. With increasing water depth, life becomes more varied: starfish appear beyond 2–3 meters along with sponges, urchins, and ascidians. At 8–10 meters the variety of starfish increases along with the general biomass, and below 30 meters there are vast colonies of these creatures. Two penguin species, Chinstrap ("Pygoscelis antarctica") and Adélie ("Pygoscelis adeliae"), are present on land.

Research stations.

The two claimant nations maintain research stations on the islands.

The South Orkney Islands are a group of islands in the Southern Ocean, about north-east of the tip of the Antarctic Peninsula and south-west of South Georgia Island. They have a total area of about. The islands are claimed both by Britain (as part of the British Antarctic Territory since 1962, previously as a Falkland Islands Dependency), and by Argentina as part of Argentine Antarctica. Under the 1959 Antarctic Treaty, sovereignty claims are held in abeyance.


Advantages.

Provided that the source and receiver impedances in a circuit are equal (it is balanced), external electromagnetic interference tends to affect both conductors identically. Since the receiving circuit only detects the difference between the wires, the technique resists electromagnetic noise compared to one conductor with an un-balanced reference (low-Ω connection to ground).  Contrary to popular belief, differential signalling does not affect noise cancellation. Balanced lines with differential receivers will reject noise regardless of whether the signal is differential or single-ended, but since balanced line noise rejection requires a differential receiver anyway, differential signalling is often used on balanced lines. This improves SNR, reduces EMI, and makes the signal more immune to ground currents or differences.  The technique works for both analog signaling, as in balanced audio—and digital signaling, as in RS-422, RS-485, Ethernet over twisted pair, PCI Express, DisplayPort, HDMI, and USB.

Suitability for use with low-voltage electronics.

The electronics industry, particularly in portable and mobile devices, continually strives to lower supply voltage to save power. A low supply voltage, however, reduces noise immunity. Differential signaling helps to reduce these problems because, for a given supply voltage, it provides twice the noise immunity of a single-ended system.  To see why, consider a single-ended digital system with supply voltage formula_1. The high logic level is formula_2 and the low logic level is 0 V. The difference between the two levels is therefore formula_3. Now consider a differential system with the same supply voltage. The voltage difference in the high state, where one wire is at formula_2 and the other at 0 V, is formula_3. The voltage difference in the low state, where the voltages on the wires are exchanged, is formula_6. The difference between high and low logic levels is therefore formula_7. This is twice the difference of the single-ended system. If the voltage noise on one wire is uncorrelated to the noise on the other one, it takes twice as much noise to cause an error with the differential system as with the single-ended system. In other words, differential signalling doubles the noise immunity.

Resistance to electromagnetic interference.

This advantage is not directly due to differential signaling itself, but to the common practice of transmitting differential signals on balanced lines. Single-ended signals are still resistant to interference if the lines are balanced and terminated by a differential amplifier.

Comparison with single-ended signaling.

In single-ended signaling, the transmitter generates a single voltage that the receiver compares with a fixed reference voltage, both relative to a common ground connection shared by both ends. In many instances single-ended designs are not feasible. Another difficulty is the electromagnetic interference that can be generated by a single-ended signaling system that attempts to operate at high speed.

Generalization: Ensemble Signaling.

The disadvantage of differential signal transmission is that it requires twice as many wires as single-ended signal transmission.  Ensemble signaling improves this by using n wires to transmit n−1 differential signals. formula_8 is equivalent to differential signalling.

2-wire ensemble signalling (encoding one signal using two wires).

Encoder: Using the generator matrix and the input vector formula_10 you get formula_11, the two signals to transmit.  Decoder: Using the control matrix formula_12 and the input vector formula_14 you get your initial vector formula_15.  By removing formula_17 from the calculation you get normal differential signaling:

4-wire ensemble signalling (encoding three signals using four wires).

Encoder: Using the generator matrix and the input vector formula_22 you get formula_11, the four signals to transmit.  Decoder: Using the control matrix formula_12 and the input vector formula_14 you get your initial vector formula_15.  By removing formula_31 from the calculation you get the matrices for ensemble signaling using four wires to transmit three signals differentially.

n-wire ensemble signalling (encoding n−1 signals using n wires).

formula_35 and formula_36.

Uses.

The technique minimizes electronic crosstalk and electromagnetic interference, both noise emission and noise acceptance, and can achieve a constant or known characteristic impedance, allowing impedance matching techniques important in a high-speed signal transmission line or high quality balanced line and balanced circuit audio signal path.  Differential pairs include:  Differential pairs generally carry differential or semi-differential signals, such as high-speed digital serial interfaces including LVDS differential ECL, PECL, LVPECL, Hypertransport, Ethernet over twisted pair, Serial Digital Interface, RS-422, RS-485, USB, Serial ATA, TMDS, FireWire, and HDMI etc. or else high quality and/or high frequency analog signals (e.g., video signals, balanced audio signals, etc.).

Transmission lines.

The type of transmission line that connects two devices (chips, modules) dictates the type of signaling. Single-ended signaling is used with coaxial cables, in which one conductor totally screens the other from the environment. All screens (or shields) are combined into a single piece of material to form a common ground. Differential signaling is used with a balanced pair of conductors. For short cables and low frequencies, the two methods are equivalent, so cheap single-ended circuits with a common ground can be used with cheap cables. As signaling speeds become faster, wires begin to behave as transmission lines.

Use in computers.

Differential signaling is often used in computers to reduce electromagnetic interference, because complete screening is not possible with microstrips and chips in computers, due to geometric constraints and the fact that screening does not work at DC. If a DC power supply line and a low-voltage signal line share the same ground, the power current returning through the ground can induce a significant voltage in it. A low-resistance ground reduces this problem to some extent. A balanced pair of microstrip lines is a convenient solution, because it does not need an additional PCB layer, as a stripline does. Because each line causes a matching image current in the ground plane, which is required anyway for supplying power, the pair looks like four lines and therefore has a shorter crosstalk distance than a simple isolated pair. In fact, it behaves as well as a twisted pair. Low crosstalk is important when many lines are packed into a small space, as on a typical PCB.

High-voltage differential signaling.

High-voltage differential (HVD) signaling uses high-voltage signals. In computer electronics, "high voltage" normally means 5 volts or more.  SCSI-1 variations included a high voltage differential (HVD) implementation whose maximum cable length was many times that of the single-ended version. SCSI equipment for example allows a maximum total cable length of 25 meters using HVD, while single-ended SCSI allows a maximum cable length of 1.5 to 6 meters, depending on bus speed. LVD versions of SCSI allow less than 25 m cable length not because of the lower voltage, but because these SCSI standards allow much higher speeds than the older HVD SCSI.  The generic term "high-voltage differential signaling" describes a variety of systems. "Low-voltage differential signaling" or LVDS, on the other hand, is a specific system defined by a TIA/EIA standard.

Differential signaling is a method for electrically transmitting information using two complementary signals. The technique sends the same electrical signal as a "differential pair" of signals, each in its own conductor. The pair of conductors can be wires (typically twisted together) or traces on a circuit board. The receiving circuit responds to the electrical difference between the two signals, rather than the difference between a single wire and ground. The opposite technique is called single-ended signalling. Differential pairs are usually found on printed circuit boards, in twisted-pair and ribbon cables, and in connectors.