3,378 research outputs found

    A performance comparison of fullband and different subband adaptive equalisers

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    We present two different fractionally spaced (FS) equalisers based on subband methods, with the aim of reducing the computational complexity and increasing the convergence rate of a standard fullband FS equaliser. This is achieved by operating in decimated subbands; at a considerably lower update rate and by exploiting the prewhitening effect that a filter bank has on the considerable spectral dynamics of a signal received through a severely distorting channel. The two presented subband structures differ in their level of realising the feedforward and feedback part of the equaliser in the subband domain, with distinct impacts on the updating. Simulation results pinpoint the faster convergence at lower cost for the proposed subband equalisers

    Hospital Cost and Efficiency Under Per Service and Per Case Payment in Maryland: A Tale of the Carrot and the Stick

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    The simultaneous operation of per case and per servicepayment systems in Maryland, and the varying levels of stringency used in setting per case rates allows comparison of effects of differing incentive structures on hospital costs. This paper presents such a comparison with 1977-1981 data. Cost per case and total cost regressions show evidence of lower costs only when per case payment limits are very stringent. Positive net revenue incentives appear insufficient to induce reductions in length of stay and in ancillary services use. Our results suggest these changes in medical practice patterns are more likely under the threat of financial losses.

    Sea-quark flavor asymmetry in the nucleon from a relativistic analysis of the Drell-Yan scattering off nuclei

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    It is shown that accounting for the relativistic structure of the deuteron allows to explain the ratio of the Drell-Yan pair production cross-section at the low Bjorken xx off the deuteron and the proton. Thus, the sea quark distributions in the nucleon should be studied with accounting for the effects of the relativistic structure of the deuteron. The suggested approach reduces theoretical uncertainty in extracting the ratio uˉ/dˉ\bar u/\bar d from the data and it is important for the clarification of the nature of the sea quark asymmetry in the nucleon.Comment: 4 pages, 1 figures, Chiral Symmetry in Hadron and Nuclear Physics November 13-16, 2007, Osak

    A Fast Converging Fractionally Spaced Equaliser

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    We present subband adaptive structures that can counteract the slow convergence which is imposed on the feed-forward part of a fractionally spaced equaliser by the spectral dynamics of the oversampled channel output. While the prewhitening of the subband approach is therefore beneficial to the feed-forward part, additionally operating the feedback part in subbands results in a more balanced and faster convergence, which is demonstrated in simulations

    A Performance Comparison of Fullband and Different Subband Equalisers

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    We present two different fractionally spaced (FS) equalisers based on subband methods, with the aim of reducing the computational complexity and increasing the convergence rate of a standard fullband FS equaliser. This is achieved by operating in decimated subbands at a considerably lower update rate and by exploiting the prewhitening effect that a filter bank has on the considerable spectral dynamics of a signal received through a severely distorting channel. The two presented subband structures differ in their level of realising the feedforward and feedback part of the equaliser in the subband domain, with distinct impacts on the updating. Simulation results pinpoint the faster convergence at lower cost for the proposed subband equalisers

    Transcription Factor Efg1 Shows a Haploinsufficiency Phenotype in Modulating the Cell Wall Architecture and Immunogenicity of Candida albicans

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    The Candida albicans transcription factor Efg1 is known to be involved in many different cellular processes, including morphogenesis, general metabolism, and virulence. Here we show that besides its manifold roles, Efg1 also has a prominent effect on cell wall structure and composition, strongly affecting the structural glucan part. Deletion of only one allele of EFG1 already results in severe phenotypes for cell wall biogenesis, comparable to those with deletion of both alleles, indicative of a severe haploinsufficiency for EFG1. The observed defects in structural setup of the cell wall, together with previously reported alterations in expression of cell surface proteins, result in altered immunogenic properties of strains with compromised Efg1 function. This is shown by interaction studies with macrophages and primary dendritic cells. The structural changes in the cell wall carbohydrate meshwork presented here, together with the manifold changes in cell wall protein composition and metabolism reported in other studies, contribute to the altered immune response mounted by innate immune cells and to the altered virulence phenotypes observed for strains lacking EFG1

    Remarks on the f_0(400-1200) scalar meson as the dynamically generated chiral partner of the pion

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    The quark-level linear sigma model is revisited, in particular concerning the identification of the f_0(400-1200) (or \sigma(600)) scalar meson as the chiral partner of the pion. We demonstrate the predictive power of the linear sigma model through the pi-pi and pi-N s-wave scattering lengths, as well as several electromagnetic, weak, and strong decays of pseudoscalar and vector mesons. The ease with which the data for these observables are reproduced in the linear sigma model lends credit to the necessity to include the sigma as a fundamental q\bar{q} degree of freedom, to be contrasted with approaches like chiral perturbation theory or the confining NJL model of Shakin and Wang.Comment: 15 pages, plain LaTeX, 3 EPS figure

    Effects of obesity on seat belt fit

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    Obesity has been shown to increase the risk of some types of injury in crashes. One hypothesis is that obesity adversely effects belt fit by changing the routing of the belt relative to the underlying skeletal structures. To evaluate this hypothesis, belt fit was measured in a laboratory study of 54 men and women, 48 percent of whom were obese, with a body mass index (BMI) of 30 kg/m2 or greater. Test conditions included a wide range of upper and lower belt anchorage locations and ranges of seat height, seat cushion angle, and seat back angle spanning a large fraction of current vehicle front and rear seats. In some conditions, foot position was restricted to simulate the typical situation in the second row of a small sedan. Across individuals, an increase in BMI of 10-kg/m2 was associated with a lap belt positioned 43 mm further forward and 21 mm higher relative to the anterior-superior iliac spines of the pelvis. Each 10-kg/m2 increase in BMI was associated with an increase in lap belt webbing length of 130 mm. The worsening of lap belt fit with restricted foot position was slightly greater for obese participants. Obesity was associated with a more-inboard shoulder belt routing across a wide range of upper belt anchorage locations, and the shoulder belt webbing length between the D-ring and latchplate increased by an average of 60 mm with each 10-kg/m2 increase in BMI. The results suggest that obesity effectively introduces slack in the seat belt system by routing the belt further away from the skeleton. Particularly in frontal crashes, but also in rollovers and other scenarios, this slack will result in increased excursions and an increased likelihood and severity of contacts with the interior. The higher routing of the lap belt with respect to the pelvis also increases the likelihood of submarining in frontal crashes.National Highway Traffic Safety Administrationhttp://deepblue.lib.umich.edu/bitstream/2027.42/89867/1/102813.pd
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