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Parasitology

Parasitology is the study of parasites, their hosts, the relationship between them. As a biological discipline, the scope of parasitology is not determined by the organism or environment in question but by their way of life; this means it forms a synthesis of other disciplines, draws on techniques from fields such as cell biology, biochemistry, molecular biology, genetics and ecology. The study of these diverse organisms means that the subject is broken up into simpler, more focused units, which use common techniques if they are not studying the same organisms or diseases. Much research in parasitology falls somewhere between two or more of these definitions. In general, the study of prokaryotes falls under the field of bacteriology rather than parasitology; the parasitologist F. E. G. Cox noted that "Humans are hosts to nearly 300 species of parasitic worms and over 70 species of protozoa, some derived from our primate ancestors and some acquired from the animals we have domesticated or come in contact with during our short history on Earth".

One of the largest fields in parasitology, medical parasitology is the subject which deals with the parasites that infect humans, the diseases caused by them, clinical picture and the response generated by humans against them. It is concerned with the various methods of their diagnosis and their prevention & control. A parasite is an organism that live within another organism called the host; these include organisms such as: Plasmodium spp. the protozoan parasite. The four species infective to humans are P. malariae, P. vivax and P. ovale. Leishmania donovani, the unicellular organism which causes leishmaniasis Entamoeba and Giardia, which cause intestinal infections Multicellular organisms and intestinal worms such as Schistosoma spp. Wuchereria bancrofti, Necator americanus and Taenia spp. Ectoparasites such as ticks and liceMedical parasitology can involve drug development, epidemiological studies and study of zoonoses; the study of parasites that cause economic losses in agriculture or aquaculture operations, or which infect companion animals.

Examples of species studied are: Lucilia sericata, a blowfly, which lays eggs on the skins of farm animals. The maggots hatch and burrow into the flesh, distressing the animal and causing economic loss to the farmer Otodectes cynotis, the cat ear mite, responsible for Canker. Gyrodactylus salaris, a monogenean parasite of salmon, which can wipe out populations which are not resistant; this is the study of structures of proteins from parasites. Determination of parasitic protein structures may help to better understand how these proteins function differently from homologous proteins in humans. In addition, protein structures may inform the process of drug discovery. Parasites exhibit an aggregated distribution among host individuals, thus the majority of parasites live in the minority of hosts; this feature forces parasitologists to use advanced biostatistical methodologies. Parasites can provide information about host population ecology. In fisheries biology, for example, parasite communities can be used to distinguish distinct populations of the same fish species co-inhabiting a region.

Additionally, parasites possess a variety of specialized traits and life-history strategies that enable them to colonize hosts. Understanding these aspects of parasite ecology, of interest in their own right, can illuminate parasite-avoidance strategies employed by hosts. Conservation biology is concerned with the protection and preservation of vulnerable species, including parasites. A large proportion of parasite species are threatened by extinction due to efforts to eradicate parasites which infect humans or domestic animals, or damage human economy, but caused by the decline or fragmentation of host populations and the extinction of host species; the huge diversity between parasitic organisms creates a challenge for biologists who wish to describe and catalogue them. Recent developments in using DNA to identify separate species and to investigate the relationship between groups at various taxonomic scales has been enormously useful to parasitologists, as many parasites are degenerate, disguising relationships between species.

Antonie van Leeuwenhoek observed and illustrated Giardia lamblia in 1681, linked it to "his own loose stools". This was the first protozoan parasite of humans that he recorded, the first to be seen under a microscope. A few years in 1687, the Italian biologists Giovanni Cosimo Bonomo and Diacinto Cestoni published that scabies is caused by the parasitic mite Sarcoptes scabiei, marking scabies as the first disease of humans with a known microscopic causative agent. In the same publication, Esperienze Intorno alla Generazione degl'Insetti, Francesco Redi described ecto- and endoparasites, illustrating ticks, the larvae of nasal flies of deer, sheep liver fluke, his earlier book Osservazioni intorno agli animali viventi che si trovano negli animali viventi described and illustrated over 100 parasites including the human roundworm. He noted. Modern parasitology developed in the 19th century with accurate observations by several researchers and clinicians. In 1828, James Annersley described amoebiasis, protozoal infections of the intestines and the liver, though the pathogen, Entamoeba histolytica, was not discovered until 1873 by Friedrich Lösch.

James Paget discovered the intestinal nematode Trichinella spiralis in humans in 1835. James McConnell described the huma

Operation Benedict

Operation Benedict was the establishment of Force Benedict with the units of the Voyenno-Vozdushnye Sily in north Russia, during the Second World War. The force comprised 151 Wing Royal Air Force, with two squadrons of Hawker Hurricane fighters; the wing flew against the Luftwaffe and the Suomen Ilmavoimat from Vaenga in northern USSR and train Soviet pilots and ground crews to operate the Hurricanes when their British pilots and ground crews returned to Britain. Twenty-four Hurricanes were delivered by Operation Strength, flying direct to Vaenga from the aircraft carrier HMS Argus but Operation Dervish, the first Arctic convoy, was diverted from Murmansk to Archangelsk another 400 mi on; the fifteen crated Hurricanes for 151 Wing had to be assembled at Keg Ostrov airstrip. Despite primitive conditions, the Hurricanes were readied in nine days, with excellent co-operation from the Russian authorities. In five weeks of operations, 151 Wing claimed 16 victories, four probables and seven aircraft damaged.

The winter snows began on 22 September and converting pilots and ground crews of Soviet Naval Aviation of the VVS to Hurricanes began in mid-October. The RAF party departed for Britain in late November, less various signals staff, arrived on 7 December and 151 Wing disbanded; the British and Russian governments gave Benedict much publicity and four members of 151 Wing received the Order of Lenin. On 22 June 1941, the Soviet Union was invaded by its allies; that evening, Winston Churchill broadcast a promise of assistance to the USSR against the common enemy. On 7 July, Churchill wrote to Stalin and ordered the British ambassador in Moscow, Stafford Cripps, to begin discussions for a treaty of mutual assistance. On 12 July, an Anglo-Soviet Agreement was signed in Moscow, to fight together and not make a separate peace. On the same day a Soviet commission met the Royal Navy and the RAF in London and it was decided to use the airfield at Vaenga as a fighter base to defend ships while unloading at the ports of Murmansk and Polyarny.

Ivan Maisky, the Soviet ambassador in London since 1932, replied on 18 July that new fronts in northern France and the Arctic would improve the situation in the USSR. Operations in the Arctic were favoured by Stalin and Churchill, but the First Sea Lord, Admiral Dudley Pound considered such proposals unsound, "with the dice loaded against us in every direction"; the US President Franklin D. Roosevelt and Churchill met at Placentia Bay, Newfoundland on 9 August and on 12 August communicated an assurance to Stalin that the western Allies were going to provide "the maximum of supplies". A joint supply mission led by W. Averell Harriman and Max Aitken arrived at Archangelsk on 27 September and on 6 October, Churchill made a commitment to sail a convoy every ten days from Iceland to north Russia; when Arctic convoys passed by the north of Norway into the Barents Sea, they came well into range of German aircraft, U-boats and ships operating from bases in Norway and Finland. The ports of arrival Murmansk, only about 15 mi east of the front line were vulnerable to attack by the Luftwaffe.

The RAF contingent was to consist of two squadrons of Hawker Hurricanes and one squadron each of twin-engined Bristol Blenheims and Bristol Beaufighters. The Commander-in-Chief of the RAF Charles Portal decided on 25 July to send only No. 151 Wing RAF comprising 81 Squadron and 134 Squadron, equipped with Hawker Hurricane Mk IIBs. A Flight of 504 Squadron, based in Exeter, formed the nucleus of a new 81 Squadron and were sent on leave, to return to RAF Leconfield in Yorkshire or had just completed their training; the wing headquarters comprised about 350 administrative, engineering, transport and non-technical staff and each squadron had a commanding officer, two flight commanders, at least thirty pilots and about 100 ground staff. The wing was to be transported to north Russia in the first Arctic convoy and was to operate until the weather in October or November grounded the aircraft. During the winter lull, the fighters were to be handed over to the Soviet Air Forces. After several delays, a 151 Wing advance party of two officers and 23 men departed from Leconfield in mid-August.

The Main Party, the majority of the 2,700 men of 151 Wing, including fourteen pilots was embarked on the troopship SS Llanstephan Castle together with 15 Hurricanes packed in crates, at the Scapa Flow anchorage in the Orkney Islands. The ships departed from Scapa Flow on 17 August 1941 with the Dervish Convoy and headed towards the Svalbard Archipelago and the midnight sun, to circle as far north around Norway as possible. Embarked were Vernon Bartlett MP, an American newspaper reporter Wallace Carrol, Feliks Topolski, the Polish expressionist painter travelling as an official British and Polish war artist, a Polish Legation, a Czechoslovak commission and Charlotte Haldane a noted feminist and member of the Communist Party of Great Britain, who lectured on Domestic life in Russia as part of an impromptu course laid on by the civilian passengers; the danger of Luftwaffe attacks on Murmansk led to the ships being diverted at Archangelsk, another 400 mi to the east. As the Llanstephan Castle sailed upriver to dock, rifle shots were heard and a member of the crew was hit in the arm, the gunfire coming from people onshore who mist

Fluence response

Both fluence rates and irradiance of light are important signals for plants and are detected by phytochrome. Exploiting different modes of photoreversibility in this molecule allow plants to respond to different levels of light. There are three main types of fluence rate governed responses that are brought about by different levels of light; as the name would suggest this type of response is triggered by low levels of light and is thought to be mediated by phytochrome A. It can be initiated by fluences as low as 0.0001μmol/m2 up to about 0.05μmol/m2. Germination of Arabidopsis can be induced with low levels of red light, as can oat seedlings; such low levels of light are sufficient for inducing this response since they only convert 0.02% of the phytochrome to its active form. The backward reaction by far red light is only 98% efficient making the conversion non-photoreversible and allowing the response to proceed. VFLRs can be induced by making up the required fluence by brief flashes of light.

Since this depends on light levels and time it is known as the law of reciprocity. These responses require at least 1μmol/m2 to be initiated and become saturated at about 1000μmol/m2. Unlike VLFRs, these responses are photoreversible; this was shown by exposing lettuce seed to a brief flash of red light causing germination. It was shown if this red flash was followed by a flash of far red light, germination was again inhibited. LFRs follow the law of reciprocity. Other examples of LFRs include leaf enhancement of rate of chlorophyll production. HIRs require long exposure to high light levels; the degree of response will depend on the level of light. They are characterised by the fact that they do not follow the law of reciprocity and depend on the rate of photons hitting the leaf surface, as opposed to the total light levels; this means that neither long exposure to dim levels of light nor bright flashes of light are enough to trigger these responses

1983 Prix de l'Arc de Triomphe

The 1983 Prix de l'Arc de Triomphe was a horse race held at Longchamp on Sunday 2 October 1983. It was the 62nd running of the Prix de l'Arc de Triomphe; the winner was All Along, a four-year-old filly trained in France by Patrick Biancone and ridden by Walter Swinburn. The filly won by a length a short neck and a nose from Sun Princess, Luth Enchantee and Time Charter in a time of 2:28.1. Fillies took the first four places in the twenty-six runner field. Sponsor: Trusthouse Forte Purse: Going: Firm Distance: 2,400 metres Number of runners: 26 Winner's time: 2:28.1 Further details of the winner, All Along. Sex: Filly Foaled: 7 April 1979 Country: France Sire: Targowice.

George Busk

George Busk FRS was a British naval surgeon and palaeontologist. Busk was born in Russia, he was the son of his wife Jane. Robert Busk was the son of Sir Wadsworth Busk, an Attorney General of the Isle of Man. Jane Busk's father, John Westly, was Customs House clerk in St. Petersburg, he studied at Dr. Hartley's School in Yorkshire, he studied surgery in London, at both St Thomas' Hospital and for one session at St Bartholomew's Hospital. Busk was appointed assistant-surgeon to the Greenwich Hospital in 1832, he served as naval surgeon first in HMS Grampus. He served for many years in HMS Dreadnought, which had fought at Trafalgar. In Busk's time it was used by the Seamen's Hospital Society as a hospital ship for ex-members of the Merchant Navy or fishing fleet and their dependants. During this period Busk made important observations on scurvy, he founded the Greenwich Natural History Society in 1852, serving as its president until 1858. In 1855, he retired from service and from medicine and settled in London, where he devoted himself to the study of zoology and palaeontology.

As early as 1842, he assisted in editing the Microscopical Journal. He was a member of the famous X-Club, founded by T. H. Huxley, active in revitalising science in the period 1865–1885. Busk and his wife Ellen were close friends of Huxley. Busk nominated Charles Darwin for membership in the Royal Society in 1864. From 1856–1859, he was Hunterian Professor of Comparative Anatomy and Physiology in the Royal College of Surgeons, he became President of the college in 1871, he was elected Fellow of the Royal Society in 1850. Busk was an active member of the Linnean Society, the Geological Society and president of the Ethnological Society and the Anthropological Institute, he received the Geological Society's Wollaston and Lyell medals. Busk was the leading authority on the Polyzoa. In 1862, Busk was again in Gibraltar, he was responsible of bringing to England the Gibraltar skull, excavated at Gibraltar in 1848. This was The identification of the skull as belonging to a Neanderthal was not made until the 20th century.

On 12 August 1843 George Busk married his first cousin. They had two daughters, he died in London on 10 August 1886 and is buried at Kensal Green Cemetery, London, in the northern section of the central circle. Aspland, Robert; the Christian Reformer. P. 602. Keith, Arthur; the Antiquity of Man. Anmol Publications. Pp. 180–1. ISBN 978-81-7041-977-8. Woodward, Bernard B.. "Busk, George". In Lee, Sidney. Dictionary of National Biography. 1. London: Smith, Elder & Co. pp. 357–358. Attribution This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed.. "Busk, George". Encyclopædia Britannica. 4. Cambridge University Press. P. 874. Works written by or about George Busk at Wikisource George Busk at Find a Grave

Osama Hamdan

Osama Hamdan is a senior representative of Hamas in Lebanon and is a member of the organization's politburo. He is a member of the Arab National Congress and of the Arab Islamic Conference of the Board of Trustees of the Jerusalem Institute in Lebanon. Hamdan was born in the Bureij refugee camp in the Gaza Strip to a Palestinian refugee family that fled the village of al-Batani al-Sharqi during the 1948 Arab-Israeli War, he attended high school in Kuwait, graduating in 1982. He enrolled at the Yarmouk University in Irbid, Jordan where he graduated with a Bachelor's Degree in Chemistry in 1986. While he was at university, Hamdan became an activist with the Islamic Student Movement, he returned to Kuwait after graduating and worked in the industrial sector until the Gulf War in 1990. After leaving Kuwait, Hamdan worked at the Hamas office in Tehran as assistant to Hamas representative Imad Alami from 1992 to 1993, he became Hamas' official representative in Iran in 1994, serving in that post until 1998.

While undertaking this post, Hamdan said that the "flourishing relations" between Iran and Hamas were at the expense of the once-good relationship between Iran and the Palestinian Liberation Organization. However, he stated "There is an absence of any proof or evidence of Iranian financial support to Hamas, Islamic Jihad and other Palestinian factions who have established contacts with Iran, it is rumours and speculation."In 1998, Hamdan was appointed as Hamas representative in Lebanon, a post he retains. In 2004, he served as Hamas' spokesman in Cairo during a dialogue between Palestinian factions, he has participated in talks between Hamas and European officials. Hamdan has advocated Palestinian unity talks and in an interview with Al-Arabiya on May 20, 2009, he said "I understand that each of us must set conditions to reach an agreement. National dialogue must be based on national interests of the Palestinian people..."In an interview which aired on Al-Jadid/New TV on May 4, 2011, Hamdan stated that "politically, the two-state solution is over" and that "we are entering the phase of the liberation of Palestine... the notion of Return: the return of the refugees to their homeland, the return of the Israelis to the countries from which they came."In an interview which aired on the Lebanese Al-Quds TV channel on July 28, 2014, Hamdan stated that "killing children...is engraved in the historical Zionist and Jewish mentality."

Commenting on the accusation of Blood Libel against Jews, Hamdan stated "we all remember how the Jews used to slaughter Christians, in order to mix their blood in their holy matzos. This is not a figment of something taken from a film, it is a fact, acknowledged by their own books and by historical evidence." In a subsequent interview with CNN's Wolf Blitzer, Hamdan defended his comments, stating that he was responding to comments made by Moshe Feiglin in the Israeli Knesset in which he called for the "complete destruction of the Palestinians in Gaza". Hamdan asserted that the organisation MEMRI had edited and'cut' his words in a selective manor taking them out of context, going on to remark that "we are not against Jews, we are against the Israeli occupation". Osama Hamdan on Charlie Rose Column archive at The Guardian Osama Hamdan collected news and commentary at Al Jazeera English