A copolymer is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization. Copolymers obtained by copolymerization of two monomer species are sometimes called bipolymers; those obtained from three and four monomers are called quaterpolymers, respectively. Commercial copolymers include acrylonitrile butadiene styrene, styrene/butadiene co-polymer, nitrile rubber, styrene-acrylonitrile, styrene-isoprene-styrene and ethylene-vinyl acetate, all formed by chain-growth polymerization. Another production mechanism is step-growth polymerization, used to produce the nylon-12/6/66 copolymer of nylon 12, nylon 6 and nylon 66, as well as the copolyester family. Since a copolymer consists of at least two types of constituent units, copolymers can be classified based on how these units are arranged along the chain. Linear copolymers consist of a single main chain, include alternating copolymers, statistical copolymers and block copolymers.
Branched copolymers consist of a single main chain with one or more polymeric side chains, can be grafted, star shaped or have other architectures. The reactivity ratio of a growing copolymer chain terminating in a given monomer is the ratio of the reaction rate constant for addition of the same monomer and the rate constant for addition of the other monomer; that is, r 1 = k 11 k 12 and r 2 = k 22 k 21, where for example k 12 is the rate constant for propagation of a polymer chain ending in monomer 1 by addition of monomer 2. The composition and structural type of the copolymer depend on these reactivity ratios r1 and r2 according to the Mayo–Lewis equation called the copolymerization equation or copolymer equation, for the relative instantaneous rates of incorporation of the two monomers. D d = Block copolymers comprise two or more homopolymer subunits linked by covalent bonds; the union of the homopolymer subunits may require an intermediate non-repeating subunit, known as a junction block.
Diblock copolymers have two distinct blocks. Technically, a block is a portion of a macromolecule, comprising many units, that has at least one feature, not present in the adjacent portions. A possible sequence of repeat units A and B in a triblock copolymer might be ~A-A-A-A-A-A-A-B-B-B-B-B-B-B-A-A-A-A-A~. Block copolymers are made up of blocks of different polymerized monomers. For example, polystyrene-b-poly or PS-b-PMMA is made by first polymerizing styrene, subsequently polymerizing methyl methacrylate from the reactive end of the polystyrene chains; this polymer is a "diblock copolymer". Triblocks, multiblocks, etc. can be made. Diblock copolymers are made using living polymerization techniques, such as atom transfer free radical polymerization, reversible addition fragmentation chain transfer, ring-opening metathesis polymerization, living cationic or living anionic polymerizations. An emerging technique is chain shuttling polymerization; the synthesis of block copolymers requires that both reactivity ratios are much larger than unity under the reaction conditions, so that the terminal monomer unit of a growing chain tends to add a similar unit most of the time.
The "blockiness" of a copolymer is a measure of the adjacency of comonomers vs their statistical distribution. Many or most synthetic polymers are in fact copolymers, containing about 1-20% of a minority monomer. In such cases, blockiness is undesirable. A block index has been proposed as a quantitative measure of blockiness or deviation from random monomer composition. An alternating copolymer has regular alternating A and B units, is described by the formula: -A-B-A-B-A-B-A-B-A-B-, or -n-; the molar ratio of each monomer in the polymer is close to one, which happens when the reactivity ratios r1 and r2 are close to zero, as can be seen from the Mayo–Lewis equation. For example, in the free-radical copolymerization of styrene maleic anhydride copolymer, r1 = 0.097 and r2 = 0.001, so that most chains ending in styren
The Oromo Liberation Front is an organisation established in 1973 by Oromo ethnonationalists-supremacists to promote the session of the Oromo people from perceived Abyssinian colonial rule in Ethiopia. The proponents of the movement hold that Amhara hegemony has been oppressing and suppressing the Oromo people and their culture; the movement is the culmination of over 70 years of uncoordinated resistance by Oromos against this condition. It has been labelled a racist and terrorist organisation by the Ethiopian government; the OLF has offices in Asmara, Washington, D. C. and Berlin from where it operates Amharic and Oromo-language radio stations. In 1967, the imperial regime of Haile Selassie I outlawed the Mecha and Tuluma Self-Help Association and instigated a wave of mass arrests and killings of its members and leaders. Prominent military officer and leader of the association, Colonel General Tadesse Birru, was arrested; this reaction by the regime had been caused by the popularity of the organization among the Oromos and its links to the Bale Oromo resistance movement.
One of the association's members, Hussein Sora, escaped to Somalia in 1967. He and other Oromo refugees formed a rebel group called the Ethiopian National Liberation Front of which he was named Secretary General; the ENLF soon began training members of the Oromo diaspora. The first attempt to enter the country was command by Jaarraa Abbaa Gadaa but it failed when Somali security forces tracked down the members and arrested them trying to enter Ethiopia through northern Somalia; the second attempt proved to be more successful and the second group of rebels made camp in the Chercher Mountains. At this point, the group decided to operate under the name of "Oromo" instead of "Ethiopia. In 1973, the political situation of the country had changed and the Ethiopian military had ousted the imperial regime and taken control. Leaders and members of the MTSHA, who had escaped arrest, had been operating secretly within the country by stirring up activism through underground newspapers such as "Kena Bektaa" and "The Oromo Voice Against Tyranny".
They organized a secret conference, attended by Hussein Sora, Elemo Qiltu and various other Oromo leaders. It was during this conference that the Oromo Liberation Front was formed and its first political program was first written out; the armed Oromo units in the Chercher Mountains were adopted as the military wing of the organization, the Oromo Liberation Army or OLA. The Oromo Liberation Army in the Chercher Mountains was placed under the command of Hassen Ibrahim, more known as Elemo Qiltu. In 1974, the OLA increased its activities in the mountains and caused much alarm amongst the administrators of the region when they killed the notorious landowner, Mulatu Tegegn; the military regime of Ethiopia sent General Getachew Shibeshi to destroy the insurrection. On September 6, 1974, the first Oromo Liberation Army was obliterated by mortar fire in the Battle of Tiro in which they lost both Ahmad Taqi and Elemo Qiltu. In an attempt to subjugate any further Oromo uprising, the Derg instigated mass arrests and killings in the surrounding urban areas of where the OLA had operated in the cities of Gelemso, Mechara and Balbaleti.
After the short lived guerrilla war, the OLF become more disorganized and a few of its leaders moved back to Aden in order to restructure the organization but to no avail. General Tadesse Birru, who had escaped from prison, continued an armed struggle in the Shewa region of the Oromo nation along with Hailu Regassa, they were captured and executed in 1976 but his OLA contingent continued fighting and gained an influx of recruits after the executions. By 1976, the Oromo Liberation Army had taken up a stronghold in the Chercher Mountains and this was used as an opportunity to reorganize the Front. A two-day secret conference was organized among Oromo leaders and the attendees hailed from all corners of Oromia and a more broadbased leadership was elected. A few members of the ENLF, who were released from custody in Somalia in 1975, others, who had entered the country on previous occasions, as well as representatives of the underground study cells, individual Oromo nationalist and patriots were members of what is now called the "Founding Congress".
The Congress issued a new detailed program. The program called for the "total liberation of the Oromo nation from Ethiopian colonialism"; the conference is now known as the Founding Congress and it marked the beginning of modern Oromo nationalism. Another front was opened by a newly formed Oromo Liberation Army, initiated in eastern Oromia by farmers. Oromo students and intellectuals in urban areas joined OLA camps by the hundreds in order to offer leadership and educational training; the first battles occurred in the rural areas around Dire Dawa such as Gara Mul'ata. The OLF subsequently spread its activities to western Oromia and elected a new 41-member central committee along with a five-member Supreme Politico Military Command which comprised Lencho Letta, Muhee Abdo, Baro Tumsa, Magarsaa Barii and Gadaa Gamada. With its structure in place, the OLF began an effective campaign to educate students and the general populace about Oromo nationalism, its military wing began capturing land in western Oromia in Wellega.
Between 1977 and 1978, the war between Somalia and Ethiopia proved to be a double-sided coin to the fortunes of the organization. Abandoned weaponry from both armies allowing more recruits to be armed. On the other hand, the Ethiopian, Somali a
Ajit Prasad Jain was an Indian politician who served as the President of the U. P. Congress Committee, member of the Constituent Assembly, Union minister and Governor of Kerala from Saharanpur, in the state of Uttar Pradesh, India, he was born in Meerut in 1902 in a middle-class family. He graduated with Honours at the Lucknow University and took his LL. B, he started his legal practice in 1926. He was an alumnus of the SM College, Chandausi Soon after A. P. Jain joined the Indian National Congress, he took part in the Civil Disobedience Movement and all Congress movements. He soon became prominent in U. P. politics. He became a member of the U. P. Congress working committee and the Secretary of Provincial Congress Committee, he was elected to the Constituent Assembly from the United Provinces. He was appointed a Parliamentary Secretary in the U. P. Government 1937 and remained in office till the resignation of the Ministry in 1939, he was a member of the All India Congress Committee for a long time. He was a minister with cabinet rank in charge of the Ministry of Rehabilitation under Nehru following the constitution of the First Lok Sabha in 1952.
He subsequently held the portfolio of Union Minister for Food and Agriculture in Mr Nehru's cabinet from December 1954 to August 1959. He became President of the U. P. Congress Committee in May 1961; when Rafi Ahmed Kidwai formed the All India Kisan Mazdoor Praja Party owing to ideological differences with the Congress president Purushottam Das Tandon, Jain handed in his resignation to Nehru in solidarity with Kidwai. Nehru however turned it down, he succeeded V V Giri as the third governor of Kerala serving from 2 April 1965 to 6 February 1966 during which time the state remained under President's rule. He resigned from the post of Governor to canvass support for Mrs Indira Gandhi for position of Prime Minister following the untimely death of Lal Bahadur Shastri, he belonged to the leftist section of the Congress and wanted to strengthen this section by opposing Morarji Desai. He was elected to the Rajya Sabha in 1967 and remained a member till 1975 He accepted the Chairmanship of the Irrigation Commission and the report of this commission remains a monumental work.
He was a member of the Zamidari Abolition Committee in UP and was instrumental in the drafting of Zamidari Abolition bill and in the plan to link the rivers of India. His far-slightness in this project and in the establishment of green revolution led to the self-sufficiency of food in India, he established Seva Nidhi Trust in Saharanpur & in Fatehpur in UP, which till date is running a house for destitutes, TB clinic & free eye camps. Additionally it gives out scholarship's to needy students; these establishments are being by his son Dr K P Jain, a renowned doctor in Delhi. Ajit Prasad Jain won the 1952 and 1957 Lok Sabha election as the Congress Party candidate from Saharanpur and from Tumkur where he won in 1962, he chaired the Uttar Pradesh Police Commission, looking into police reforms in the state, from 1960 and it submitted its report in 1961. His Shadow of the bear: The Indo-Soviet treaty was published in 1971 and Kashmir: what happened, based on his recollection of events that led to the arrest of Sheikh Abdullah in 1953, in 1972.
Ajit Prasad Jain died on 2 January 1977 at the age of 75. List of Kerala Governor The city of hope: the Faridabad story By L. C. Jain http://dspace.wbpublibnet.gov.in:8080/jspui/bitstream/10689/11626/9/Chapter%204_221-273p.pdf
Pachyrhinosaurus is an extinct genus of centrosaurine ceratopsid dinosaur from the Late Cretaceous period of North America. The first examples were discovered by Charles M. Sternberg in Alberta, Canada, in 1946, named in 1950. Over a dozen partial skulls and a large assortment of other fossils from various species have been found in Alberta and Alaska. A great number were not available for study until the 1980s, resulting in a recent increase of interest in Pachyrhinosaurus. Three species have been identified. P. lakustai, from the Wapiti Formation, the bonebed horizon of, equivalent age to the upper Bearpaw and lower Horseshoe Canyon Formations, is known to have existed from about 73.5–72.5 million years ago. P. canadensis is younger, known from the lower Horseshoe Canyon Formation, about 71.5–71 Ma ago and the St. Mary River Formation. Fossils of the youngest species, P. perotorum, have been recovered from the Prince Creek Formation of Alaska, date to 70–69 Ma ago. The presence of three known species makes.
The largest Pachyrhinosaurus species were 8 metres long. It weighed about four tonnes, they possessed strong cheek teeth to help them chew tough, fibrous plants. Instead of horns, their skulls bore flattened bosses. A prominent pair of horns grew from extended upwards; the skull bore several smaller horns or ornaments that varied between individuals and between species. In P. canadensis and P. perotorum, the bosses over the nose and eyes nearly grew together, were separated only by a narrow groove. In P. lakustai, the two bosses were separated by a wide gap. In P. canadensis and P. lakustai, the frill bore two additional small, backward-pointed horns. These were not present in P. perotorum, in fact some specimens of P. lakustai lack them, which may indicate that the presence of these horns varied by age or sex. Various ornaments of the nasal boss have been used to distinguish between different species of Pachyrhinosaurus. Both P. lakustai and P. perotorum bore a jagged, comb-like extension at the tip of the boss, missing in P. canadensis.
P. perotorum was unique in having a narrow dome in the middle of the back portion of the nasal boss, P. lakustai had a pommel-like structure projecting from the front of the boss. P. perotorum bore two unique, flattened horns which projected forward and down from the top edge of the frill, P. lakustai bore another comb-like horn arising from the middle of the frill behind the eyes. Pachyrhinosaurus canadensis, was described in 1950 by Charles Mortram Sternberg based on the holotype incomplete skull NMC 8867, the paratype incomplete skull NMC 8866, which included the anterior part of the skull but was lacking the right lower mandible, the "beak"; these skulls were collected in 1945 and 1946 from the sandy clay of the Horseshoe Canyon Formation in Alberta, Canada. In the years to come, additional material would be recovered at the Scabby Butte locality of the St. Mary River Formation near Lethbridge, from terrestrial sediments considered to be between 74 and 66 million years old; these were in the 1880s.
The significance of these discoveries was not understood until shortly after World War II when preliminary excavations were conducted. Another Pachyrhinosaurus skull was taken out of the Scabby Butte locality in 1955, in 1957 Wann Langston Jr. and a small crew excavated additional pachyrhinosaur remains. The University of Calgary has plans to reopen this important site some day as a field school for university-level paleontology students. Several specimens, NMC 21863, NMC 21864, NMC 10669 assigned in 1975 by W. Langston, Jr. to Pachyrhinosaurus were recovered at the Scabby Butte locality. Another Pachyrhinosaurus bonebed, on the Wapiti River south of Beaverlodge in northwestern Alberta, was worked by staff of the Royal Tyrrell Museum in the late 1980s but is now worked annually for a couple weeks each summer by the University of Alberta. Material from this site appears referable to Pachyrhinosaurus canadensis. In 1974, Grande Prairie, Alberta science teacher Al Lakusta found a large bonebed along Pipestone Creek in Alberta.
When the area was excavated between 1986 and 1989 by staff and volunteers of the Royal Tyrrell Museum of Palaeontology, paleontologists discovered an amazingly large and dense selection of bones—up to 100 per square meter, with a total of 3,500 bones and 14 skulls. This was the site of a mass mortality a failed attempt to cross a river during a flood. Found amongst the fossils were the skeletons of four distinct age groups ranging from juveniles to full-grown dinosaurs, indicating that the Pachyrhinosaurus cared for their young; the adult skulls had both convex and concave bosses as well as unicorn-style horns on the parietal bone just behind their eyes. The concave boss types might be related to erosion only and not reflect male/female differences. In 2008, a detailed monograph describing the skull of the Pipestone Creek pachyrhinosaur, penned by Philip J. Currie, Wann Langston Jr. and Darren Tanke, classified the specimen as a second species of Pachyrhinosaurus, named P. lakustai after its discoverer.
In 2013, Fiorillo et al. described a new specimen, an incomplete nasal bone attributable to Pachyrhinosaurus perotorum, collected from the Kikak-Tegoseak Quarry on the Colville River in Alaska. Fiorillo et al. named this unique northern Alaskan species after the Texas oi
Penicillium waksmanii is an anamorph species of the genus of Penicillium, isolated from the alga Sargassum ringgoldianum. Penicillium waksmanii produces pyrenocine A, pyrenocine C, pyrenocine D and pyrenocine E Petit, K. E.. F.. "Detection of griseofulvin in a marine strain of Penicillium waksmanii by ion trap mass spectrometry". Journal of Microbiological Methods. 58: 59–65. Doi:10.1016/j.mimet.2004.03.004. PMID 15177904. Graminho, E. R.. Applied Biochemistry and Biotechnology. 169: 201–14. Doi:10.1007/s12010-012-9974-3. PMID 23179282. Fakhar, Mahdi. "In vitro protoscolicidal effects of fungal chitosan isolated from Penicillium waksmanii and Penicillium citrinum". Journal of Parasitic Diseases. 39: 162–7. Doi:10.1007/s12639-013-0300-y. PMC 4456528. PMID 26063992. Kushida, Nobuaki. "PF1270A, B and C, Novel Histamine H3 Receptor Ligands Produced by Penicillium waksmanii PF1270". The Journal of Antibiotics. 60: 667–73. Doi:10.1038/ja.2007.85. PMID 18057695. LD Khemani. Chemistry of Phytopotentials: Health and Environmental Perspectives.
Springer Science & Business Media. ISBN 978-3-642-23394-4. Q. Ashton Acton. Neutral Amino Acids—Advances in Research and Application. ScholarlyEditions. ISBN 978-1-4816-7809-4
Vegar Heggenes Gjermundstad is a Norwegian football defender who plays for Førde IL. He hails from Vadheim, he started his career in Vadheim IL and IL Høyang, but moved in 2006 to attend the school Norsk Toppidrettsgymnas as well as to play for FC Lyn Oslo. In the summer of 2008 he signed for Lyn's senior team, he has two Norwegian Premier League games in 2009, making his debut on 19 April 2009 against Strømsgodset and starting his first game on 3 May 2009 against Stabæk Fotball. His 27th and last game came in May 2010. Following the bankruptcy of Lyn, he joined Sogndal IL in July 2010. Vegar Gjermundstad at the Norwegian Football Federation