3,503 research outputs found

    Blood flow dynamics in patient specific arterial network in head and neck

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    This paper shows a steady simulation of blood flow in the major head and neck arteries as if they had rigid walls, using patient specific geometry and CFD software FLUENT R . The Artery geometry is obtained by CT–scan segmentation with the commercial software ScanIPTM. A cause and effect study with various Reynolds numbers, viscous models and blood fluid models is provided. Mesh independence is achieved through wall y+ and pressure gradient adaption. It was found, that a Newtonian fluid model is not appropriate for all geometry parts, therefore the non–Newtonian properties of blood are required for small vessel diameters and low Reynolds numbers. The k–! turbulence model is suitable for the whole Reynolds numbe

    Band gap bowing in NixMg1-xO.

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    Epitaxial transparent oxide NixMg1-xO (0 ≤ x ≤ 1) thin films were grown on MgO(100) substrates by pulsed laser deposition. High-resolution synchrotron X-ray diffraction and high-resolution transmission electron microscopy analysis indicate that the thin films are compositionally and structurally homogeneous, forming a completely miscible solid solution. Nevertheless, the composition dependence of the NixMg1-xO optical band gap shows a strong non-parabolic bowing with a discontinuity at dilute NiO concentrations of x  0.074 and account for the anomalously large band gap narrowing in the NixMg1-xO solid solution system

    Long term monitoring of bright TeV Blazars with the MAGIC telescope

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    The MAGIC telescope has performed long term monitoring observations of the bright TeV Blazars Mrk421, Mrk501 and 1ES1959+650. Up to 40 observations, 30 to 60 minutes each have been performed for each source evenly distributed over the observable period of the year. The sensitivity of MAGIC is sufficient to establish a flux level of 25% of the Crab flux for each measurement. These observations are well suited to trigger multiwavelength ToO observations and the overall collected data allow an unbiased study of the flaring statistics of the observed AGNs.Comment: 4 pages, 4 figures, to appear in the proceedings of the 30th International Cosmic Ray Conference, Merida, July 200

    Exploring the virtual space of academia

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    The aim of this chapter is to provide a view on how researchers present themselves in a social network specifically developed for supporting academic practices, how they share information and engage in dialogues with colleagues worldwide. We analysed data from 30,428 users who have registered on a publicly available website to study the effect of academic position, university ranking and country on people's behaviour. Results suggest that the virtual network closely mirrors physical reality, reproducing the same hierarchical structure imposed by position, ranking, and country on user behaviour. Despite the potential for bridging and bonding social capital the networks have not achieved substantial changes in structures and practices of the academic context. Furthermore, our analysis highlights the need of finding new strategies to motivate the users to contribute to the community and support equal participation, as so far the community is mainly exploited as a static website

    Detection of an Optical Counterpart to the ALFALFA Ultra-compact High Velocity Cloud AGC 249525

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    We report on the detection at >>98% confidence of an optical counterpart to AGC 249525, an Ultra-Compact High Velocity Cloud (UCHVC) discovered by the ALFALFA blind neutral hydrogen survey. UCHVCs are compact, isolated HI clouds with properties consistent with their being nearby low-mass galaxies, but without identified counterparts in extant optical surveys. Analysis of the resolved stellar sources in deep gg- and ii-band imaging from the WIYN pODI camera reveals a clustering of possible Red Giant Branch stars associated with AGC 249525 at a distance of 1.64±\pm0.45 Mpc. Matching our optical detection with the HI synthesis map of AGC 249525 from Adams et al. (2016) shows that the stellar overdensity is exactly coincident with the highest-density HI contour from that study. Combining our optical photometry and the HI properties of this object yields an absolute magnitude of −7.1≤MV≤−4.5-7.1 \leq M_V \leq -4.5, a stellar mass between 2.2±0.6×104M⊙2.2\pm0.6\times10^4 M_{\odot} and 3.6±1.0×105M⊙3.6\pm1.0\times10^5 M_{\odot}, and an HI to stellar mass ratio between 9 and 144. This object has stellar properties within the observed range of gas-poor Ultra-Faint Dwarfs in the Local Group, but is gas-dominated.Comment: 9 pages, 4 figures; accepted to ApJ

    QUANTITATIVE ANALYSIS OF SHAPE VARIATION IN TYPE AND MODERN POPULATIONS OF MERIDION (BACILLARIOPHYCEAE)

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65187/1/j.1529-8817.2001.037001175.x.pd
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