3,209 research outputs found

    Bandverbindungen der Dornfortsätze der Wirbelsäule

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    In the cervical region the fibres of the interspinous and nuchal ligaments pass in an anteroc ranial direction: they act against diminishing of the cervical lordosis. In the thoracic region, longitudinal bundles of fibres connect the tops of the spinous processes; they act against an augmentation of the thoracal kyphosis. Between thoracal kyphosis and lumbal lordosis there is no exact course of the fibres of the interspinous ligts. ("thorakolumbaler "Übergangsbereich"). In the lumbar spine the fibres of the interspinous ligts., being very strong, pass in a posterocranial direction. They have the function of limitation the range of flexion ventrally and of limiting backwards - shifting of the cranial vertebra in dorsal-flexion. In the lumbosacral segment additional fibres, arising from the top of the 5th lumbar spinous process, pass in a posterocaudal direction and interlace with the thoracolumbar fascia , whose fibres form — below the 4 th lumbarvertebra — ascissor - latticed structure. The supraspinous ligt. lies superficially to the thoracolumbar fascia. Its fibres pass several spinous processes. I t ends caudally at the 4th lumbar spinous process

    Improved computational treatment of transonic flow about swept wings

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    Relaxation solutions to classical three-dimensional small-disturbance (CSD) theory for transonic flow about lifting swept wings are reported. For such wings, the CSD theory was found to be a poor approximation to the full potential equation in regions of the flow field that are essentially two-dimensional in a plane normal to the sweep direction. The effect of this deficiency on the capture of embedded shock waves in terms of (1) the conditions under which shock waves can exist and (2) the relations they must satisfy when they do exist is emphasized. A modified small-disturbance (MSD) equation, derived by retaining two previously neglected terms, was proposed and shown to be a consistent approximation to the full potential equation over a wider range of sweep angles. The effect of these extra terms is demonstrated by comparing CSD, MSD, and experimental wing surface pressures

    Direct Measurement of Effective Magnetic Diffusivity in Turbulent Flow of Liquid Sodium

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    The first direct measurements of effective magnetic diffusivity in turbulent flow of electro-conductive fluids (the so-called beta-effect) under magnetic Reynolds number Rm >> 1 are reported. The measurements are performed in a nonstationary turbulent flow of liquid sodium, generated in a closed toroidal channel. The peak level of the Reynolds number reached Re \approx 3 10^6, which corresponds to the magnetic Reynolds number Rm \approx 30. The magnetic diffusivity of the liquid metal was determined by measuring the phase shift between the induced and the applied magnetic fields. The maximal deviation of magnetic diffusivity from its basic (laminar) value reaches about 50% .Comment: 5 pages, 6 figuser, accepted in PR

    Back-Propagation of Physiological Action Potential Output in Dendrites of Slender-Tufted L5A Pyramidal Neurons

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    Pyramidal neurons of layer 5A are a major neocortical output type and clearly distinguished from layer 5B pyramidal neurons with respect to morphology, in vivo firing patterns, and connectivity; yet knowledge of their dendritic properties is scant. We used a combination of whole-cell recordings and Ca2+ imaging techniques in vitro to explore the specific dendritic signaling role of physiological action potential patterns recorded in vivo in layer 5A pyramidal neurons of the whisker-related ‘barrel cortex’. Our data provide evidence that the temporal structure of physiological action potential patterns is crucial for an effective invasion of the main apical dendrites up to the major branch point. Both the critical frequency enabling action potential trains to invade efficiently and the dendritic calcium profile changed during postnatal development. In contrast to the main apical dendrite, the more passive properties of the short basal and apical tuft dendrites prevented an efficient back-propagation. Various Ca2+ channel types contributed to the enhanced calcium signals during high-frequency firing activity, whereas A-type K+ and BKCa channels strongly suppressed it. Our data support models in which the interaction of synaptic input with action potential output is a function of the timing, rate and pattern of action potentials, and dendritic location

    Application of Alloy 718 in M-1 engine components

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    Alloy 718 applied to components of M-1 rocket engin

    On the effects of turbulence on a screw dynamo

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    In an experiment in the Institute of Continuous Media Mechanics in Perm (Russia) an non--stationary screw dynamo is intended to be realized with a helical flow of liquid sodium in a torus. The flow is necessarily turbulent, that is, may be considered as a mean flow and a superimposed turbulence. In this paper the induction processes of the turbulence are investigated within the framework of mean--field electrodynamics. They imply of course a part which leads to an enhanced dissipation of the mean magnetic field. As a consequence of the helical mean flow there are also helical structures in the turbulence. They lead to some kind of α\alpha--effect, which might basically support the screw dynamo. The peculiarity of this α\alpha--effect explains measurements made at a smaller version of the device envisaged for the dynamo experiment. The helical structures of the turbulence lead also to other effects, which in combination with a rotational shear are potentially capable of dynamo action. A part of them can basically support the screw dynamo. Under the conditions of the experiment all induction effects of the turbulence prove to be rather weak in comparison to that of the main flow. Numerical solutions of the mean--field induction equation show that all the induction effects of the turbulence together let the screw dynamo threshold slightly, at most by one per cent, rise. The numerical results give also some insights into the action of the individual induction effects of the turbulence.Comment: 15 pages, 7 figures, in GAFD prin

    Power and Persuasion in the Vaccine Debates: An Analysis of Political Efforts and Outcomes in the United States, 1998‐2012

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108619/1/milq12075.pd

    Direct evidence for the magnetic ordering of Nd ions in NdFeAsO by high resolution inelastic neutron scattering

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    We investigated the low energy excitations in the parent compound NdFeAsO of the Fe-pnictide superconductor in the μ\mueV range by a back scattering neutron spectrometer. The energy scans on a powder NdFeAsO sample revealed inelastic peaks at E = 1.600 ±0.003μ \pm 0.003 \mueV at T = 0.055 K on both energy gain and energy loss sides. The inelastic peaks move gradually towards lower energy with increasing temperature and finally merge with the elastic peak at about 6 K. We interpret the inelastic peaks to be due to the transition between hyperfine-split nuclear level of the 143^{143}Nd and 145^{145}Nd isotopes with spin I=7/2I = 7/2. The hyperfine field is produced by the ordering of the electronic magnetic moment of Nd at low temperature and thus the present investigation gives direct evidence of the ordering of the Nd magnetic sublattice of NdFeAsO at low temperature
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