8,562 research outputs found

    Caryophyllales 2015 in Berlin and the Global Caryophyllales Initiative

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    Fil: Arias, Salvador. Universidad Nacional Autónoma de México; MéxicoFil: Berendsohn, Walter G.. Freie Universität Berlin; AlemaniaFil: Borsch, Thomas. Freie Universität Berlin; AlemaniaFil: Flores Olvera, Hilda. Universidad Nacional Autónoma de México; MéxicoFil: Ochoterena, Helga. Universidad Nacional Autónoma de México; MéxicoFil: von Mering, Sabine. Freie Universität Berlin; AlemaniaFil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentin

    The radial variation of HI velocity dispersions in dwarfs and spirals

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    Gas velocity dispersions provide important diagnostics of the forces counteracting gravity to prevent collapse of the gas. We use the 21 cm line of neutral atomic hydrogen (HI) to study HI velocity dispersion and HI phases as a function of galaxy morphology in 22 galaxies from The HI Nearby Galaxy Survey (THINGS). We stack individual HI velocity profiles and decompose them into broad and narrow Gaussian components. We study the HI velocity dispersion and the HI surface density, as a function of radius. For spirals, the velocity dispersions of the narrow and broad components decline with radius and their radial profiles are well described by an exponential function. For dwarfs, however, the profiles are much flatter. The single Gaussian dispersion profiles are, in general, flatter than those of the narrow and broad components. In most cases, the dispersion profiles in the outer disks do not drop as fast as the star formation profiles, derived in the literature. This indicates the importance of other energy sources in driving HI velocity dispersion in the outer disks. The radial surface density profiles of spirals and dwarfs are similar. The surface density profiles of the narrow component decline more steeply than those of the broad component, but not as steep as what was found previously for the molecular component. As a consequence, the surface density ratio between the narrow and broad components, an estimate of the mass ratio between cold HI and warm HI, tends to decrease with radius. On average, this ratio is lower in dwarfs than in spirals. This lack of a narrow, cold HI component in dwarfs may explain their low star formation activity.Comment: Accepted for publication in The Astronomical Journal, 13 pages, 10 figures, 4 table

    Novel treatment strategies for chronic kidney disease: insights from the animal kingdom

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    Many of the >2 million animal species that inhabit Earth have developed survival mechanisms that aid in the prevention of obesity, kidney disease, starvation, dehydration and vascular ageing; however, some animals remain susceptible to these complications. Domestic and captive wild felids, for example, show susceptibility to chronic kidney disease (CKD), potentially linked to the high protein intake of these animals. By contrast, naked mole rats are a model of longevity and are protected from extreme environmental conditions through mechanisms that provide resistance to oxidative stress. Biomimetic studies suggest that the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) offers protection in extreme environmental conditions and promotes longevity in the animal kingdom. Similarly, during months of fasting, immobilization and anuria, hibernating bears are protected from muscle wasting, azotaemia, thrombotic complications, organ damage and osteoporosis - features that are often associated with CKD. Improved understanding of the susceptibility and protective mechanisms of these animals and others could provide insights into novel strategies to prevent and treat several human diseases, such as CKD and ageing-associated complications. An integrated collaboration between nephrologists and experts from other fields, such as veterinarians, zoologists, biologists, anthropologists and ecologists, could introduce a novel approach for improving human health and help nephrologists to find novel treatment strategies for CKD

    Efficient parallel computation on workstation clusters

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    We present novel hard- and software that efficiently implements communication primitives for parallel execution on Workstation clusters. We provide low communication latencies, minimal protocol, zero operating system overhead, and high throughput. With this technology, it is possible to build effective parallel systems using off-the-shelf workstations. Our goal is to develop a standard interfaceboard and the necessary software for interfacing any number of computers, from a workstation to a cabinet full of workstation-boards

    Double Trouble for Type 1 Angiotensin Receptors in Atherosclerosis

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    The researchers then found that the levels and activity of activated factor XIII (factor XIIIa) transglutaminase were higher in the monocytes from hypertensive patients than in those from normotensive subjects. Transglutaminases are a family of calcium-dependent enzymes that catalyze the cross-linking of proteins, including membrane proteins, through the amino acids glutamine and lysine.5 Factor XIIIa is best known for cross-linking the fibrin network during blood coagulation

    Latency hiding in parallel systems: a quantitative approach

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    In many parallel applications, network latency causes a dramatic loss in processor utilization. This paper examines software pipelining as a technique for network latency hiding. It quantifies the potential improvements with detailed,instruction-level simulations. The benchmarks used are the Livermore Loop kernels and BLAS Level 1. These were parallelized and run on the instruction-level RISC simulator DLX, extended with both a blocking and a pipelined network. Our results show that prefetch in a pipelined network improves performance by a factor of 2 to 9, provided the network has sufficient bandwidth to accept at least 10 requests per processor

    The star-formation law at GMC scales in M33, the Triangulum Galaxy

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    We present a high spatial resolution study, on scales of ∼\sim100pc, of the relationship between star-formation rate (SFR) and gas content within Local Group galaxy M33. Combining deep SCUBA-2 observations with archival GALEX, SDSS, WISE, Spitzer and submillimetre Herschel data, we are able to model the entire SED from UV to sub-mm wavelengths. We calculate the SFR on a pixel-by-pixel basis using the total infrared luminosity, and find a total SFR of 0.17±0.06 M⊙0.17 \pm 0.06\,\rm{M}_\odot/yr, somewhat lower than our other two measures of SFR -- combined FUV and 24μ\mum SFR (0.25−0.07+0.10 M⊙0.25^{+0.10}_{-0.07}\,\rm{M}_\odot/yr) and SED-fitting tool MAGPHYS (0.33−0.06+0.05 M⊙0.33^{+0.05}_{-0.06}\,\rm{M}_\odot/yr). We trace the total gas using a combination of the 21cm HI line for atomic hydrogen, and CO(J\textit{J}=2-1) data for molecular hydrogen. We have also traced the total gas using dust masses. We study the star-formation law in terms of molecular gas, total gas, and gas from dust. We perform an analysis of the star-formation law on a variety of pixel scales, from 25′′^{\prime\prime} to 500′′^{\prime\prime} (100pc to 2kpc). At kpc scales, we find that a linear Schmidt-type power law index is suitable for molecular gas, but the index appears to be much higher with total gas, and gas from dust. Whilst we find a strong scale dependence on the Schmidt index, the gas depletion timescale is invariant with pixel scale.Comment: 19 pages, 15 figures, accepted for publication in MNRA
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