192 research outputs found

    A gel electrophoretic study of the protein and nucleic acid components of African horsesickness virus

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    The physico-chemical structure of African horse sickness virus (AHSV) is compared with that of some of the other members of the Reoviridae, and in particular with that of bluetongue virus (BTV), the type strain of the orbivirus genus. This study adduces evidence of a great similarity between the gel electrophoretic patterns of the polypeptides of AHSV and BTV. The molecular mass values of the 7 AHSV polypeptides range between 0,30 x 10⁵ and 1, 46 x 10⁵ dalton, a variation similar to that of BTV. The close relation between AHSV and BTV is further affirmed by the gel electrophoretic resolution of the AHSV double-stranded RNA genome into 10 segments.The articles have been scanned in colour with a HP scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to final presentyation PDF-Format

    Detection of African horsesickness virus and discrimination between two equine orbivirus serogroups by reverse transcription polymerase chain reaction

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    A reverse transcription polymerase chain reaction (RT-PCR), based on the gene encoding the NS2 protein of African horsesickness virus (AHSV), was developed for rapid serogroup-specific detection of AHSV. The specificity of RT-PCR products was confirmed by Southern blot hybridization using a radioactively labelled cDNA probe specific for the NS2 gene. This RT-PCR could discriminate between all known members of the AHSV and equine encephalosis virus serogroups. AHSV RNA was detected in a sample representing 0,005 plaque forming units in a dilution series made of infected cell culture material. In an immune horse which had been vaccinated with a baculovirus expressed AHSV (serotype 4) VP2 subunit vaccine, viral RNA could be detected for up to 22 weeks post challenge. AHSV RNA was detected in various organs of an infected horse. Viral RNA was also detected by RT-PCR in nine suspected field cases of African horsesickness while virus isolation was successfully performed on eight of these cases.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

    A comparison of an Australian bluetongue virus isolate (CSIRO 19) with other bluetongue virus serotypes by cross-hybridization and cross-immune precipitation

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    No major differences in size were observed when both the double-stranded RNA and the polypeptides of the Australian bluetongue virus (BTV) isolate CSIRO 19 (BTV-20) were compared with those of other BTV serotypes such as BTV-10 and BTV-4. Minor capsid polypeptide P6 of both BTV-20 and BTV-4, which electrophoreses as a single band on continuous phosphate buffered gels, is separated into 2 distinct bands on discontinuous glycine-buffered gels. This was not the case with BTV-10. Cross-immune precipitation of BTV-20 with BTV-10, BTV-17, BTV-4 and BTV-3 indicated strong immunological cross-reaction of the group-specific antigen P7 of the different serotypes. There was also some cross-immune precipitation of the serotype-specific polypeptide P2 of BTV-20 and BTV-4. This result is in agreement with the observed cross neutralization of these 2 viruses. The main distinction between BTV-20 and the other BTV serotypes was observed in crosshybridization experiments. The homology between the nucleic acid of BTV-20 and other BTV serotypes was less than 30%, whereas homology normally found between BTV serotypes is at least 70%. The hybridization products of the different BTV serotypes were analysed by electrophoresis and fluorography. Two main hybrid segments were observed in all heterologous hybridizations with BTV-20 as compared with 7 hybrid segments in hybridizations between BTV-4 and BTV-10. In order to determine from which genome segment of BTV -20 these 2 hybrid segments were derived, the hybridizations were carried out with individually purified double-stranded RNA segments. These results indicate that the 2 segments of BTV-20 that show the largest homology to corresponding segments of a heterologous BTV serotype are No. 7 and 10.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

    The nucleic acid and proteins of epizootic haemorrhagic disease virus

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    Purified epizootic haemorrhagic disease virus (EHDV) was shown to contain 10 double-stranded RNA segments and a double-layered protein capsid with 4 major and 4 minor polypeptides. The virus differed from bluetongue virus (BTV), the orbivirus prototype, in that EHDV had an additional minor polypeptide component. This component, together with the major polypeptides P2 and P5, formed the outer capsid layer of the virus. The extra polypeptide apparently stabilizes this layer since, unlike BTV, EHDV was quite stable on CsC1 gradients at both pH 7,0 and 8,0. EHD virions were found to have a density of 1,36 g/mℓ, while particles without the outer capsid layer were isolated and had a density of 1,40 g/mℓ. Two non-capsid polypeptides, P5A and P6A, were identified in addition to the 8 capsid polypeptides. Polypeptide P5A was synthesized in excess of all the others. There was little homology between the nucleic acids of EHDV and BTV with only 5-10% cross-hybridization. No hybrid double-stranded RNA segments were identified. We found by cross-immune precipitation that the major core polypeptides of the 2 viruses (P7 and P3) have common antigenic determinants.This article has been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-Format

    The prevalence of different African horsesickness virus serotypes in the Onderstepoort area near Pretoria, during an outbreak of African horsesickness in South Africa in 1995/1996

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    During 1995/1996 parts of South Africa experienced exceptionally high rainfall. Large numbers of Culicoides midges were seen and an outbreak of African horse sickness (AHS) followed. In the Onderstepoort area, near Pretoria in Gauteng, a number of horses died of suspected AHS. Virus isolation and typing was done from blood and/or organ samples of 21 suspected cases as well as from 5 zebra which were kept in the area. Virus was isolated from 14 of the 21 suspected cases but not from the zebra. The neutralizing antibody response of the zebra to the nine African horsesickness virus (AHSV) serotypes was determined. Results indicated the highest prevalence of serotypes 2 and 4 followed by serotypes 1, 6 and 9. Reverse transcription polymerase chain reaction (RT-PCR) was performed on total RNA extracted from blood samples of the zebra. AHSV RNA was detected in three of five zebra by agarose gel electrophoresis analysis of amplicons and in four of five zebra after Southern blot hybridization using a 32P-labelled probe. RT-PCR can be used together with serological techniques in studies of AHS to further clarify the epizootiology of the disease.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

    Accounting for International War: The State of the Discipline

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    In studies of war it is important to observe that the processes leading to so frequent an event as conflict are not necessarily those that lead to so infrequent an event as war. Also, many models fail to recognize that a phenomenon irregularly distributed in time and space, such as war, cannot be explained on the basis of relatively invariant phenomena. Much research on periodicity in the occurrence of war has yielded little result, suggesting that the direction should now be to focus on such variables as diffusion and contagion. Structural variables, such as bipolarity, show contradictory results with some clear inter-century differences. Bipolarity, some results suggest, might have different effects on different social entities. A considerable number of studies analysing dyadic variables show a clear connection between equal capabilities among contending nations and escalation of conflict into war. Finally, research into national attributes often points to strength and geographical location as important variables. In general, the article concludes, there is room for modest optimism, as research into the question of war is no longer moving in non-cumulative circles. Systematic research is producing results and there is even a discernible tendency of convergence, in spite of a great diversity in theoretical orientations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69148/2/10.1177_002234338101800101.pd

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

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    Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter
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