16 research outputs found

    The performance of the jet trigger for the ATLAS detector during 2011 data taking

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    The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided proton–proton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleon–nucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Events are accepted by the trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction

    Comparison of bacterial communities associated with Xestospongia testudinaria, sediment and seawater in a Singaporean coral reef ecosystem

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    Despite alterations caused by anthropogenic activities in Singaporean coral reefs, the sponge communities are quite diverse and Xestospongia testudinaria is one of the most common sponge species. In the present study, we used 16S rRNA gene barcoded pyrosequencing to characterize and compare bacterial communities from different biotopes (sponge, seawater and sediment) and to identify dominant bacterial symbionts of X. testudinaria in a Singaporean coral reef ecosystem. Our results showed that biotope appears to affect the richness, composition and abundance of bacterial communities. Proteobacteria was the most abundant phylum in sediment and seawater whilst Chloroflexi was more abundant in X. testudinaria. Members of the order Caldilineales (fermentation of organic substrates), Chromatiales (purple sulphur bacteria), Rhodospirillales (purple non-sulphur bacteria) and Syntrophobacterales (sulphate-reducing bacteria) were relatively more abundant in X. testudinaria samples.publishe

    Microbial bioconversion of palm oil mill effluent to citric acid with optimum process conditions

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    Oil palm industry has an important role in contributing to the Malaysian economy. Several million tonnes of crude palm oil is produced annually and approximately, about 10 million tonnes of palm oil mill effluent (POME) (highly polluted organic effluent) is generated every year. Citric acid is a commercially valuable product widely used in many industries. More than 400,000 tonnes of citric acid is produced annually by fermentation of expensive raw materials like glucose and sucrose. Efficient and effective methods of producing citric acid from different cheaper raw materials have been of great interest to many researchers, due to its extensive use. This study is an effort to achieve the goal by introducing a new substrate POME and a potential isolated strain of Asperillus niger. The method used was liquid state bioconversion with optimum process conditions obtained from our previous studies using central composite design (CCD)from Minitab software. The optimized parameters were temperature, agitation rate, inoculum size and pH. Analysis has been done everyday up to seven days of fermentation. Performance of the developed process was evaluated on the basis of maximum citric acid (5.24 g/L), chemical oxygen demand removal (COD), total suspended solid (TSS) and removal of heavy metals (cadmium chromium and copper)

    Rhizosphere bacterial communities of potato cultivars evaluated through PCR-DGGE profiles Comunidades bacterianas associadas à rizosfera de cultivares de batata avaliadas por perfis de PCR-DGGE

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    The objective of this work was to determine the shifts on the PCR-DGGE profiles of bacterial communities associated to the rhizosphere of potato cultivars, in order to generate baseline information for further studies of environmental risk assessment of genetically modified potato plants. A greenhouse experiment was carried out with five potato cultivars (Achat, Bintje, Agata, Monalisa and Asterix), cultivated in pots containing soil from an integrated system for agroecological production. The experiment was conducted in a split plot randomized block design with five cultivars, three sampling periods and five replicates. Rhizosphere samples were collected in three sampling dates during plant development. DNA of rhizosphere microorganisms was extracted, amplified by PCR using bacterial universal primers, and analyzed through DGGE. Shifts on the rhizosphere bacterial communities associated to rhizosphere of different cultivars were related to both cultivar and plant age. Differences among rhizosphere bacterial communities were clearest at the earliest plant age, tending to decrease in later stages. This variation was detected among bacterial communities of the five tested cultivars. The characterization of soil microbial communities can be part of plant breeding programs to be used on studies of environmental risk assessment of genetically modified potatoes.<br>O objetivo deste trabalho foi determinar as alterações nos perfis de PCR-DGGE das comunidades bacterianas associadas à rizosfera de cultivares de batata, para obter informações para futuros estudos de avaliação de risco ambiental de plantas de batatas geneticamente modificadas. Foi conduzido experimento em casa de vegetação com cinco cultivares de batata (Achat, Bintje, Ágata, Monalisa e Asterix), cultivadas em vasos com solo de um sistema integrado de produção agroecológica. O delineamento experimental foi o de blocos ao acaso, em parcelas subdivididas, com cinco cultivares, três períodos amostrais e cinco repetições. As amostras de rizosfera foram coletadas em três diferentes épocas durante o desenvolvimento das plantas. O DNA dos microrganismos associados à rizosfera foi extraído, amplificado por PCR com uso de iniciadores universais para bactérias e analisados por DGGE. Foram observadas alterações, relacionadas à cultivar e à idade da planta, nos perfis das comunidades bacterianas associadas à rizosfera das diferentes cultivares. As diferenças entre as comunidades bacterianas foram maiores na fase inicial do crescimento das plantas, com tendência a diminuir no estágio final de desenvolvimento. Essa variação foi detectada na comunidade bacteriana das cinco cultivares estudadas. A caracterização da microbiota do solo pode ser parte de programas de melhoramento de plantas a ser utilizada em estudos de avaliação de risco ambiental de batatas geneticamente modificadas

    Comunidade bacteriana como indicadora do efeito de feijoeiro geneticamente modificado sobre organismos não alvo Bacterial community as an indicator of genetically modified common bean effect on nontarget organisms

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    O objetivo deste trabalho foi avaliar o efeito do feijoeiro geneticamente modificado quanto à resistência ao Bean Golden Mosaic Vírus, BGMV (Olathe M1-4), sobre organismos não alvo. De um experimento implantado no campo, em delineamento inteiramente casualizado, com dois tratamentos (Olathe Pinto e evento elite Olathe M1-4), dois períodos amostrais (estádio V4 e R6) e dez repetições, obtiveram-se células bacterianas cultivadas e não cultivadas da rizosfera e do solo não rizosférico, para as quais se procedeu à extração de DNA total. A região V6-V8 do 16S rDNA foi amplificada para a comunidade bacteriana total, e também realizou-se amplificação com iniciadores específicos para o subgrupo alfa (&#945;) do filo Proteobacteria a partir de células não cultivadas. Foram obtidos dendrogramas comparativos entre a variedade Olathe Pinto (convencional) e o evento elite Olathe M1-4 (geneticamente modificado) utilizando-se o coeficiente de Jaccard e o método UPGMA (Unweighted pair-group method with arithmetic mean). Os agrupamentos obtidos dos perfis de 16S rDNA PCR-DGGE indicam alterações na comunidade bacteriana da rizosfera em função da transformação das plantas são mais notáveis nos perfis obtidos para alfa-proteobacteria. A origem das amostras e o estágio de desenvolvimento das plantas afetam a comunidade bacteriana.<br>The objective of this work was to evaluate the effect of genetically modified common bean for Bean Golden Mosaic Virus, BGMV, resistance (Olathe M1-4) on nontarget organisms. In a field experiment established in a completely randomized design with two treatments (Olathe Pinto cultivar and M1-4 Olathe elite event), two sampling periods (V4 and R6 stages) and ten replicates, cultivated and non-cultivated bacterial cells from rhizosphere soil and bulk soil were obtained, and their total DNA was extracted. The V6-V8 region of 16S rDNA was amplified for the whole bacterial community, and primers specific for the alpha (&#945;) subgroup of the Proteobacteria phylum were obtained from uncultured cells and used for amplification. Using the Jaccard coefficient and UPGMA (Unweighted pair-group method with arithmetic mean), dendrograms comparing the conventional Olathe Pinto and the elite event Olathe M1-4 transgenic varieties were obtained. The clusters obtained from the 16S rDNA PCR-DGGE profiles indicate changes in the rhizosphere bacterial community in genetically modified plants, being more notable in the profiles obtained for alphaproteobacteria. Sample origin and plant development stages affect bacterial community profiles
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