35 research outputs found

    Search for Exotic Strange Quark Matter in High Energy Nuclear Reactions

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    We report on a search for metastable positively and negatively charged states of strange quark matter in Au+Pb reactions at 11.6 A GeV/c in experiment E864. We have sampled approximately six billion 10% most central Au+Pb interactions and have observed no strangelet states (baryon number A < 100 droplets of strange quark matter). We thus set upper limits on the production of these exotic states at the level of 1-6 x 10^{-8} per central collision. These limits are the best and most model independent for this colliding system. We discuss the implications of our results on strangelet production mechanisms, and also on the stability question of strange quark matter.Comment: 21 pages, 9 figures, to be published in Nuclear Physics A (Carl Dover memorial edition

    Search for Strange Quark Matter Produced in Relativistic Heavy Ion Collisions

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    We present the final results from Experiment 864 of a search for charged and neutral strange quark matter produced in interactions of 11.5 GeV/c per nucleon Au beams with Pt or Pb targets. Searches were made for strange quark matter with A>4. Approximately 30 billion 10% most central collisions were sampled and no strangelet states with A<100 were observed. We find 90% confidence level upper limits of approximately 10^{-8} per central collision for both charged and neutral strangelets. These limits are for strangelets with proper lifetimes greater than 50 ns. Also limits for H^{0}-d and pineut production are given. The above limits are compared with the predictions of various models. The yields of light nuclei from coalescence are measured and a penalty factor for the addition of one nucleon to the coalescing nucleus is determined. This is useful in gauging the significance of our upper limits and also in planning future searches for strange quark matter.Comment: 35 pages, 18 figures, submitted to Phys. Rev.

    Investigation of inter- and intraspecies variation through genome sequencing of Aspergillus section Nigri

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    Aspergillus section Nigri comprises filamentous fungi relevant to biomedicine, bioenergy, health, and biotechnology. To learn more about what genetically sets these species apart, as well as about potential applications in biotechnology and biomedicine, we sequenced 23 genomes de novo, forming a full genome compendium for the section (26 species), as well as 6 Aspergillus niger isolates. This allowed us to quantify both inter-and intraspecies genomic variation. We further predicted 17,903 carbohydrateactive enzymes and 2,717 secondary metabolite gene clusters, which we condensed into 455 distinct families corresponding to compound classes, 49% of which are only found in single species. We performed metabolomics and genetic engineering to correlate genotypes to phenotypes, as demonstrated for the metabolite aurasperone, and by heterologous transfer of citrate production to Aspergillus nidulans. Experimental and computational analyses showed that both secondary metabolism and regulation are key factors that are significant in the delineation of Aspergillus species.Peer reviewe

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    Not AvailableThe present study investigates the issue of marine debris and the associated soil, sediment, water quality, and microbial load from the fish landing centres (Junglighat, Chatham, Wandoor, and Guptapara) of South Andaman. The results revealed that significantly (P < 0.05) higher number and weight of marine debris was found in urban landing centres such as Chatham (21.26 ± 1.03 numbers/m2) and Junglighat (268.16 ± 27.00 g/m2), respectively. Plastic debris was found to be the most abundant type of debris, among which plastic bags were dominant. Better soil, sediment, and water quality parameters were observed in rural landing centres such as Wandoor and Guptapara, whereas microbial load was found to be higher in urban landing centres. The study recommends the imperative need to generate awareness on better management practices among the stakeholders to deal with the issue of marine debris and to aim sustainable management of the coastal environment.Not Availabl

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    Not AvailableThe present study investigates the issue of marine debris and the associated soil, sediment, water quality, and microbial load from the fish landing centres (Junglighat, Chatham, Wandoor, and Guptapara) of South Andaman. The results revealed that significantly (P < 0.05) higher number and weight of marine debris was found in urban landing centres such as Chatham (21.26 ± 1.03 numbers/m2) and Junglighat (268.16 ± 27.00 g/m2), respec- tively. Plastic debris was found to be the most abundant type of debris, among which plastic bags were dominant. Better soil, sediment, and water quality parameters were observed in rural landing centres such as Wandoor and Guptapara, whereas microbial load was found to be higher in urban landing centres. The study recommends the imperative need to generate awareness on better management practices among the stakeholders to deal with the issue of marine debris and to aim sustainable management of the coastal environment.Not Availabl
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