673 research outputs found

    Constraints for the nuclear parton distributions from Z and W production at the LHC

    Full text link
    The LHC is foreseen to finally bring also the nuclear collisions to the TeV scale thereby providing new possibilities for physics studies, in particular related to the electro-weak sector of the Standard Model. We study here the Z and W production in proton-lead and lead-lead collisions at the LHC, concentrating on the prospects of testing the factorization and constraining the nuclear modifications of the parton distribution functions (PDFs). Especially, we find that the rapidity asymmetries in proton-nucleus collisions, arising from the differences in the PDFs between the colliding objects, provide a decisive advantage in comparison to the rapidity-symmetric nucleus-nucleus case. We comment on how such studies will help to improve our knowledge of the nuclear PDFs.Comment: The version accepted for publication in JHEP. New figures has been added, and we also discuss the single charged lepton productio

    Evidence for Escherichia coli DcuD carrier dependent FOF1-ATPase activity during fermentation of glycerol

    Get PDF
    During fermentation Escherichia coli excrete succinate mainly via Dcu family carriers. Current work reveals the total and N,N’-dicyclohexylcarbodiimide (DCCD) inhibited ATPase activity at pH 7.5 and 5.5 in E. coli wild type and dcu mutants upon glycerol fermentation. The overall ATPase activity was highest at pH 7.5 in dcuABCD mutant. In wild type cells 50% of the activity came from the FOF1-ATPase but in dcuD mutant it reached ~80%. K+ (100 mM) stimulate total but not DCCD inhibited ATPase activity 40% and 20% in wild type and dcuD mutant, respectively. 90% of overall ATPase activity was inhibited by DCCD at pH 5.5 only in dcuABC mutant. At pH 7.5 the H+ fluxes in E. coli wild type, dcuD and dcuABCD mutants was similar but in dcuABC triple mutant the H+ flux decreased 1.4 fold reaching 1.15 mM/min when glycerol was supplemented. In succinate assays the H+ flux was higher in the strains where DcuD is absent. No significant differences were determined in wild type and mutants specific growth rate except dcuD strain. Taken together it is suggested that during glycerol fermentation DcuD has impact on H+ fluxes, FOF1-ATPase activity and depends on potassium ions
    • …
    corecore