18 research outputs found

    Thread-Scalable Evaluation of Multi-Jet Observables

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    A leading-order, leading-color parton-level event generator is developed for use on a multi-threaded GPU. Speed-up factors between 150 and 300 are obtained compared to an unoptimized CPU-based implementation of the event generator. In this first paper we study the feasibility of a GPU-based event generator with an emphasis on the constraints imposed by the hardware. Some studies of Monte Carlo convergence and accuracy are presented for PP -> 2,...,10 jet observables using of the order of 1e11 events.Comment: 16 pages, 5 figures, 3 table

    Equine infectious anemia : prevalence in working equids of livestock herds, in Minas Gerais, Brazil

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    Estimaram-se, no estado de Minas Gerais, a prevalência e a distribuição espacial da anemia infecciosa eqüina (AIE) em propriedades com eqüídeos de serviço. As amostras de sangue, de 6540 eqüídeos de 1940 rebanhos foram coletadas no período de setembro de 2003 a março de 2004, nos 853 municípios do estado. Utilizaram-se dois testes de laboratório em seqüência: ELISA, usando-se antígeno recombinante gp90, e imunodifusão em gel de ágar (IDGA). As prevalências foram de 5,3% [IC=4,3 a 6,3%] para rebanhos e de 3,1% [IC=2,2 a 3,9%] para animais. O estado de Minas Gerais foi considerado área endêmica para AIE. As mais altas prevalências para rebanhos e para animais foram encontradas na região Norte/Noroeste, seguida pela região Vale do Mucuri/Jequitinhonha. ___________________________________________________________________________________________________________ ABSTRACTThe prevalence and spatial distribution of equine infectious anemia (EIA) were estimated in livestock herds where equids were used as draft power and for transportation in the State of Minas Gerais, Brazil. Serum samples were collected from September/2003 to March/2004 in 853 municipalities of the state. The sample comprised 6,540 equids from 1,940 herds. Two laboratorial tests were performed in sequence: ELISA using a recombinant gp90 protein, following by the AGID. The prevalence in the herds was estimated in 5.3% [CI = 4.3 to 6.3%], and 3.1% [CI = 2.2 to 3.9%] of the animals tested were positive. Minas Gerais was considered an endemic region for EIA. The highest prevalence for herds and animals was found in North/Northwest region (strata) followed by Vale do Mucuri/Jequitinhonha region

    Search for H→γγ produced in association with top quarks and constraints on the Yukawa coupling between the top quark and the Higgs boson using data taken at 7 TeV and 8 TeV with the ATLAS detector

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    A search is performed for Higgs bosons produced in association with top quarks using the diphoton decay mode of the Higgs boson. Selection requirements are optimized separately for leptonic and fully hadronic final states from the top quark decays. The dataset used corresponds to an integrated luminosity of 4.5 fb−14.5 fb−1 of proton–proton collisions at a center-of-mass energy of 7 TeV and 20.3 fb−1 at 8 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. No significant excess over the background prediction is observed and upper limits are set on the tt¯H production cross section. The observed exclusion upper limit at 95% confidence level is 6.7 times the predicted Standard Model cross section value. In addition, limits are set on the strength of the Yukawa coupling between the top quark and the Higgs boson, taking into account the dependence of the tt¯H and tH cross sections as well as the H→γγ branching fraction on the Yukawa coupling. Lower and upper limits at 95% confidence level are set at −1.3 and +8.0 times the Yukawa coupling strength in the Standard Model

    Spectroscopic and theoretical studies on the excited state in diimine dithiolate complexes of platinum(II)

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    The photophysical properties of a series of Pt(N-N)(S-S) complexes have been studied where (N-N) is either an \u3b1,\u3b1\u2032-diimine or saturated diamine chelating ligand and (S-S) is either a dithiolate chelating ligand or two monothiolate ligands in order to determine the orbital composition of the excited state. The solvent dependence of the absorption spectra of these complexes and the temperature dependence of their emission intensities and lifetimes have been examined while the ligands have been systematically varied. The electronic spectra are found to be dependent on whether or not the nitrogen chelating ligand is unsaturated (contains a vacant \u3c0* orbital). All of the unsaturated diimine complexes show an intense solvatochromic band in the visible region of their electronic spectra which shifts to higher energy with increasing solvent polarity. In the related complexes in which a saturated diamine chelating ligand replaces the unsaturated diimine chelating ligand, no solvatochromism is observed. On the basis of the spectroscopic data, the lowest energy absorption band in the diimine complexes is assigned as a metal-dithiolate to \u3c0*(diimine) transition, whereas in the diamine complexes it is assigned as a metal-to-dithiolate MLCT transition. The only room-temperature emissive complexes are those that contain an \u3b1,\u3b1\u2032-diimine chelating ligand. The nature of the emission in these complexes at all temperatures depends on the dithiolate ligand, and the temperature dependence of the emission spectra has been examined. When (S-S) is the 1,2-dithiolate maleonitriledithiolate (mnt), the emission in rigid glass is structured and shows single exponential behavior with both emission intensity and lifetime, increasing with decreasing temperature. For the other (S-S) complexes studied, the emission in rigid glass shows evidence of multiple emitting states based on the observation that lifetimes increase while emission quantum yields decrease as the temperature is lowered. The nature of the HOMO and LUMO has been examined experimentally using cyclic voltammetry. On the basis of the electrochemical and spectroscopic data, the emission from all of the Pt(diimine)(S-S) complexes except those of mnt is assigned as a 3{d(Pt)/p(S)-\u3c0*(diimine)} transition, while, for the mnt complexes, it corresponds to a 3{d(Pt)/p(S)-\u3c0*(mnt)} transition. These assignments are supported by extended H\ufcckel molecular orbital calculations

    Giardia spp. e Cryptosporidium spp. em água de manancial superficial de abastecimento contaminada por dejetos humano e animal Giardia spp. and Cryptosporidium spp. in a fresh water supply source contaminated with human and animal excreta and waste water

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    Estudou-se ocorrência de cistos de Giardia spp. e oocistos de Cryptosporidium spp. - (oo)cistos - na bacia hidrográfica do Ribeirão São Bartolomeu, localizada no município de Viçosa, MG. O estudo incluiu as populações humana e animal existentes na área da bacia, bem como no efluente de uma estação de tratamento de esgoto (ETE) e de duas instalações para suínos. Os resultados indicam presença de (oo)cistos no manancial (médias geométricas: 3,92 e 3,62 (oo)cistos/l para Giardia spp. e Cryptosporidium spp., respectivamente). Propriedades com exploração bovina foram positivas ao longo de todo período (prevalência média de propriedades positivas 36,4% para Giardia spp. e 18,0% para Cryptosporidium spp.). O efluente da ETE apresentou elevada concentração de cistos de Giardia spp. (média geométrica na ordem de 10(4)/l), mas não foram encontrados oocistos de Cryptosporidium spp. A ocorrência de (oo)cistos apresentou comportamento sazonal, sendo que os valores médios de (oo)cistos e de pluviosidade do trimestre de coleta revelaram bom ajuste de correlação (R²=98,3%; P=0,0087 para Giardia spp. e R²=91,8%; P=0,0421 para Cryptosporidium spp.). A significativa ocorrência de (oo)cistos no manancial sugere que a forma de ocupação do solo interfere na qualidade parasitológica da água bruta. Os resultados apontam para a importância de adoção de medidas preventivas, como proteção de áreas de mananciais, objetivando reduzir riscos de transmissão de protozoários via água de consumo humano.The occurrence of Giardia spp. cysts and Cryptosporidium spp. oocysts - (oo)cysts - was studied in a watershed (São Bartolomeu Stream-SB), at Viçosa city, MG. In the studied area, characterization of animal farms and identification of sewage and animal wastes discharges were undertaken. In addition, a sewage treatment plant (STP) and effluents of two swine farms were sampled. The results presented protozoan contamination (geometric averages: 3.92 and 3.62 (oo)cysts/l for Giardia spp. and Cryptosporidium spp., respectively). Positive cattle farms were detected during all the period, and the correspondent mean prevalences were: 36.4% for Giardia spp. and 18.0% for Cryptosporidium spp. STP effluent presented high concentration of Giardia spp. (geometric average of cysts in the order of 10(4)/l). However, Cryptosporidium spp. oocysts were not detected. The results showed that (oo)cysts concentration were influenced by climate factors. Precipitation and (oo)cysts concentration data were well correlated (R²=98.3%; P=0.0087 for Giardia spp. and R²=91.8%; P=0.0421 for Cryptosporidium spp.). Cysts and oocysts levels were remarkably high in the raw water source, pointing out the role of land use in an unprotected watershed as a source of protozoa. The results demonstrate the importance of preventive measures rather than relying on, sometimes unreliable, corrective measures such as water treatment, in order to minimize human health risks

    Aplicação da técnica de PCR na detecção de Yersinia enterocolitica em suínos abatidos sem inspeção PCR technique application in Yersinia enterocolitica detection in non-inspected swine

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    Avaliou-se a contaminação de carcaças e tonsilas de suínos por Y. enterocolitica em estabelecimentos de abate não inspecionados, comparando a pesquisa microbiológica convencional com a técnica da reação em cadeia de polimerase (PCR) e o tipo de amostra analisada (de tonsila ou de carcaça), como subsídio ao monitoramento microbiano em sistemas de análise de perigos e pontos críticos de controle. Calcularam-se os custos dos dois testes. Não se detectou Y. enterocolitica pela técnica microbiológica convencional, mas, pela técnica de PCR foi possível detectar a bactéria em 40% das carcaças e em 43% das tonsilas, incluindo cepas patogênicas nas tonsilas. Não houve diferença entre os resultados positivos para as amostras de tonsilas e esfregaços de superfície das carcaças. A PCR apresentou-se como uma alternativa na detecção do agente e uma técnica aparentemente mais eficaz, econômica e rápida. Os resultados indicam a PCR como um importante recurso para o controle de qualidade da carne suína.The contamination of swine carcasses and tonsils by Yersinia enterocolitica in slaughterhouses without inspection was evaluated. The conventional microbiological analysis was compared with the PCR technique of carcass or tonsil swabs, as a subsidy to the microbiological evaluation in the HACCP system. The costs of the two techniques were also calculated. Y. enterocolitica was not detected by the conventional microbiological analysis. Using the PCR, it was possible to detect this bacterium in carcass (40%) and tonsil (43%) samples. There was no difference between the positive results for the carcass and tonsil samples. The PCR showed to be a more effective, fast and economic alternative for the Y. enterocolitica detection, as compared to the conventional microbiological analysis
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