9,028 research outputs found

    Electrolyte management in porous battery components. Static measurements

    Get PDF
    The interaction between the porous hydrogen and nickel electrodes and microporous separator with respect to electrolyte management in nickel/hydrogen cells has been investigated. The distribution of electrolyte among the components has been measured and correlated with the pore size distributions, total void volume, and resistance of a variety of electrodes and separators. Calculations are used to show the effects of systematically varying these properties

    Protostellar Feedback Processes and the Mass of the First Stars

    Full text link
    We review theoretical models of Population III.1 star formation, focusing on the protostellar feedback processes that are expected to terminate accretion and thus set the mass of these stars. We discuss how dark matter annihilation may modify this standard feedback scenario. Then, under the assumption that dark matter annihilation is unimportant, we predict the mass of stars forming in 12 cosmological minihalos produced in independent numerical simulations. This allows us to make a simple estimate of the Pop III.1 initial mass function and how it may evolve with redshift.Comment: 6 pages, Proceedings of 'The First Stars and Galaxies: Challenges for the Next Decade", Austin, TX, March 8-11, 201

    microRNAs of parasitic helminths – identification, characterization and potential as drug targets

    Get PDF
    microRNAs (miRNAs) are small non-coding RNAs involved in post-transcriptional gene regulation. They were first identified in the free-living nematode Caenorhabditis elegans, where the miRNAs lin-4 and let-7 were shown to be essential for regulating correct developmental progression. The sequence of let-7 was subsequently found to be conserved in higher organisms and changes in expression of let-7, as well as other miRNAs, are associated with certain cancers, indicating important regulatory roles. Some miRNAs have been shown to have essential functions, but the roles of many are currently unknown. With the increasing availability of genome sequence data, miRNAs have now been identified from a number of parasitic helminths, by deep sequencing of small RNA libraries and bioinformatic approaches. While some miRNAs are widely conserved in a range of organisms, others are helminth-specific and many are novel to each species. Here we review the potential roles of miRNAs in regulating helminth development, in interacting with the host environment and in development of drug resistance. Use of fluorescently-labeled small RNAs demonstrates uptake by parasites, at least in vitro. Therefore delivery of miRNA inhibitors or mimics has potential to alter miRNA activity, providing a useful tool for probing the roles of miRNAs and suggesting novel routes to therapeutics for parasite control

    Recent advances in Ni-H2 technology at NASA Lewis Research Center

    Get PDF
    The NASA Lewis Research Center has concentrated its efforts on advancing the Ni-H2 system technology for low Earth orbit applications. Component technology as well as the design principles were studied in an effort to understand the system behavior and failure mechanisms in order to increase performance and extend cycle life. The design principles were previously addressed. The component development is discussed, in particular the separator and nickel electrode and how these efforts will advance the Ni-H2 system technology

    Cluster optimisation using Cgroups at a tier-2

    Get PDF
    The Linux kernel feature Control Groups (cgroups) has been used to gather metrics on the resource usage of single and eight-core ATLAS workloads. It has been used to study the effects on performance of a reduction in the amount of physical memory. The results were used to optimise cluster performance, and consequently increase cluster throughput by up to 10%

    The military and administrative reforms of the emperor Gallienus

    Get PDF
    The military and administrative reforms of Gallienus affected the tactical organisation of the army, the composition and structure of the officer corps, and the social composition of the provincial administration. Gallienus' tactical reforms created a powerful body of cavalry, which represented the culmination to a century of increasing mobility and depth in defence. This "battlecavalry" was not the direct ancestor of the later comitatenses. but its tactical value and elite status paved the way for a "dual" system of defence involving frontier garrisons and centralised field-armies. His reforms of the officer corps involved the replacement of senatorial officers by equestrians, and the introduction of the protectorate. He hoped thereby to bind military commanders more closely to himself. The administrative reforms involved increasing the number of equestrian governors. Though senatorial governorships continued to occur, senators were henceforth without any real military power. Whether Gallienus ever issued an "edict" to this effect is uncertain, as is the motive behind the reform. Most scholars see in it an attempt to improve the quality of military leadership, but there is little evidence for this. It is preferable to agree with Aurelius Victor, that Gallienus feared the senators, and so deprived them of their commands. Together, Gallienus' creation of the "battlecavalry" and his reforms of the officer corps and provincial administration created the pre-conditions for the recovery of the Roman empire under the Illyrian emperors, and laid the foundations to the "Military Monarchy" of the later Roman empire
    • …
    corecore