2,100 research outputs found

    Soft – Partial Frequency Reuse Method for LTE-A

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    In the paper a novel SPFR frequency reuse method is proposed which can be used for improvement of physical resources utilization efficiency in LTE-A. The proposed method combines both SFR and PFR giving the possibility of more flexible use of frequency band in different regions of a cell. First, a short study on the problem of frequency reuse in cells is discussed including bibliography overview. In next section the principle of the proposed SPFR method is described. Then the simulation model is discussed and simulation parameters are expected. In the last part, results of simulation of SPFR efficiency in comparison to known frequency reuse methods are presented. Presented results include both capacity and throughput for single connection. The proposed method eliminates main disadvantages of both SFR and PFR methods and gives significantly greater capacity of radio interface in boundary region of cells

    Longtime behavior of nonlocal Cahn-Hilliard equations

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    Here we consider the nonlocal Cahn-Hilliard equation with constant mobility in a bounded domain. We prove that the associated dynamical system has an exponential attractor, provided that the potential is regular. In order to do that a crucial step is showing the eventual boundedness of the order parameter uniformly with respect to the initial datum. This is obtained through an Alikakos-Moser type argument. We establish a similar result for the viscous nonlocal Cahn-Hilliard equation with singular (e.g., logarithmic) potential. In this case the validity of the so-called separation property is crucial. We also discuss the convergence of a solution to a single stationary state. The separation property in the nonviscous case is known to hold when the mobility degenerates at the pure phases in a proper way and the potential is of logarithmic type. Thus, the existence of an exponential attractor can be proven in this case as well

    Comparison of dichotomized and distributional approaches in rare event clinical trial design: a fixed Bayesian design

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    Accepted 14 July 2016This research was motivated by our goal to design an efficient clinical trial to compare two doses of docosahexaenoic acid supplementation for reducing the rate of earliest preterm births (ePTB) and/or preterm births (PTB). Dichotomizing continuous gestational age (GA) data using a classic binomial distribution will result in a loss of information and reduced power. A distributional approach is an improved strategy to retain statistical power from the continuous distribution. However, appropriate distributions that fit the data properly, particularly in the tails, must be chosen, especially when the data are skewed. A recent study proposed a skew-normal method. We propose a three-component normal mixture model and introduce separate treatment effects at different components of GA. We evaluate operating characteristics of mixture model, beta-binomial model, and skew-normal model through simulation. We also apply these three methods to data from two completed clinical trials from the USA and Australia. Finite mixture models are shown to have favorable properties in PTB analysis but minimal benefit for ePTB analysis. Normal models on log-transformed data have the largest bias. Therefore we recommend finite mixture model for PTB study. Either finite mixture model or beta-binomial model is acceptable for ePTB study.Yang Lei, Susan Carlson, Lisa N. Yelland, Maria Makrides, Robert Gibson and Byron J. Gajewsk

    Microwave properties of (PrxY1x)Ba2Cu3O7δ(Pr_xY_{1-x})Ba_2Cu_3O_{7-\delta} : Influence of magnetic scattering

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    We report measurements of the surface impedance Zs=Rs+iXsZ_s=R_s+iX_s of (PrxY1x)Ba2Cu3O7δ(Pr_xY_{1-x})Ba_2Cu_3O_{7-\delta}, (x=0,0.15,0.23,0.3,0.4,0.5)(x=0,0.15,0.23,0.3,0.4,0.5). Increasing PrPr concentration leads to some striking results not observed in samples doped by non-magnetic constituents. The three principal features of the Rs(T)R_s(T) data - multiple structure in the transition, a high residual resistance and, at high PrPr concentrations, an upturn of the low TT data, are all characteristic of the influence of magnetic scattering on superconductivity, and appear to be common to materials where magnetism and superconductivity coexist. The low TT behavior of λ(T)\lambda (T) appears to change from TT to T4T^4 at large PrPr doping, and provides evidence of the influence of magnetic pairbreaking of the PrPr.Comment: 5 pages, 3 eps figures, Revtex, 2-column format, uses graphicx. To appear in Physica C. Postscript version also available at http://sagar.physics.neu.edu/preprints.htm

    Engineering fatty acid synthases for directed polyketide production.

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    In this study, we engineered fatty acid synthases (FAS) for the biosynthesis of short-chain fatty acids and polyketides, guided by a combined in vitro and in silico approach. Along with exploring the synthetic capability of FAS, we aim to build a foundation for efficient protein engineering, with the specific goal of harnessing evolutionarily related megadalton-scale polyketide synthases (PKS) for the tailored production of bioactive natural compounds

    Reliability of Peak Treadmill Exercise Tests in Mild Alzheimer Disease

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    This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Neuroscience on August 2011, available online: http://www.tandfonline.com/10.3109/00207454.2011.574762.The prevalence of Alzheimer disease (AD) doubles every 5 years after the age of 65, reaching nearly 50% after age 85 (Evans et al., 1989). This, along with an unprecedented growth in the elderly population, is leading to dramatic increases in the incidence of AD. Thus, effective strategies for promoting healthy brain aging and preventing AD are increasingly important. One strategy that appears promising in promoting healthy brain aging is exercise and physical activity. Evidence is accumulating that endurance exercise is beneficial to brain health (Laurin, Verreault, Lindsay, MacPherson, & Rockwood, 2001), and increased cardiorespiratory fitness is associated with increased brain volume in subjects with very mild to mild AD (Burns et al., 2008). While enhancing cardiorespiratory fitness may be a strategy for preventing cognitive decline in AD, there is limited information available on the validity and reliability of cardiorespiratory fitness measures in this population. The gold standard measure of cardiorespiratory fitness is maximum oxygen consumption (VO2max) (Frankin, 2001), the highest rate of oxygen uptake attainable during maximal or exhaustive exercise (American College of Sports Medicine, 2005). If the subject becomes exhausted and ends the test prior to reaching the physiologic VO2max, the end of the test is called peak oxygen consumption (VO2peak). It is unknown if advanced age and cognitive difficulties in people with AD would limit their ability to fully participate in a standard graded exercise test to reliably assess VO2max or VO2peak. Treadmill exercise testing has been found to be reliable in subjects with traumatic brain injury and mental retardation, although these subjects were very young (Fernhall, Millar, Tymeson, & Burkett, 1990; Mossberg & Greene, 2005). Traumatic brain injury and mental retardation are different disease processes than AD and would be expected to result in static rather than progressive cognitive symptoms. With AD, memory is impaired as is the ability to follow commands, however patients in the earliest stages of AD would be expected to respond to prompting and reminders to follow testing procedures. To our knowledge, no studies have assessed the reliability of peak treadmill exercise testing in subjects with AD. In our previous research on patients with very mild to mild AD (Burns, et al., 2008), we have found them to be capable of ambulating on a treadmill and completing peak treadmill exercise testing with 3 participants out of 74 (126 total peak exercise tests) identified as having EKG changes during testing. All 3 participants had negative follow-up testing in cardiology. The purpose of this study was to investigate the reliability of a graded peak treadmill exercise test in elderly people with early AD

    31P-NMR and muSR Studies of Filled Skutterudite Compound SmFe4P12: Evidence for Heavy Fermion Behavior with Ferromagnetic Ground State

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    The 31P-NMR (nuclear magnetic resonance) and muSR (muon spin relaxation) measurements on the filled skutterudite system SmFe4P12 have been carried out. The temperature T dependence of the 31P-NMR spectra indicates the existence of the crystalline electric field effect splitting of the Sm3+$ (J = 5/2) multiplet into a ground state and an excited state of about 70 K. The spin-lattice relaxation rate 1/T1 shows the typical behavior of the Kondo system, i.e., 1/T1 is nearly T independent above 30 K, and varies in proportion to T (the Korringa behavior, 1/T1 \propto T) between 7.5 K and 30 K. The T dependence deviated from the Korringa behavior below 7 K, which is independent of T in the applied magnetic field of 1 kOe, and suppressed strongly in higher fields. The behavior is explained as 1/T1is determined by ferromagnetic fluctuations of the uncovered Sm3+ magnetic moments by conduction electrons. The muSR measurements in zero field show the appearance of a static internal field associated with the ferromagnetic order below 1.6 K.Comment: 6 pages, 9 figures, to be published in J. Phys. Soc. Jpn. 75 (2006

    Next-gen sequencing identifies non-coding variation disrupting miRNA-binding sites in neurological disorders

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    Funding: This work was funded by a Marie Curie Career Integration Grant and by a Max Planck Research Group Grant both awarded to SCV. The work of the Newbury lab is funded by the Medical Research Council (G1000569/1 and MR/J003719/1). XSC, AG, CF and SEF were supported by the Max Planck Society. The UK Medical Research Council and the Wellcome Trust (Grant ref: 102215/2/13/2) and the University of Bristol provided core support for ALSPAC. The work of the Wellcome Trust Centre in Oxford is supported by the Wellcome Trust (090532/Z/09/Z). JH was supported by a scholarship from the Agency for Science, Technology, and Research, Singapore. The work of SDS is supported by the grant HD027802 from NIH.Understanding the genetic factors underlying neurodevelopmental and neuropsychiatric disorders is a major challenge given their prevalence and potential severity for quality of life. While large-scale genomic screens have made major advances in this area, for many disorders the genetic underpinnings are complex and poorly understood. To date the field has focused predominantly on protein coding variation, but given the importance of tightly controlled gene expression for normal brain development and disorder, variation that affects non-coding regulatory regions of the genome is likely to play an important role in these phenotypes. Herein we show the importance of 3 prime untranslated region (3'UTR) non-coding regulatory variants across neurodevelopmental and neuropsychiatric disorders. We devised a pipeline for identifying and functionally validating putatively pathogenic variants from next generation sequencing (NGS) data. We applied this pipeline to a cohort of children with severe specific language impairment (SLI) and identified a functional, SLI-associated variant affecting gene regulation in cells and post-mortem human brain. This variant and the affected gene (ARHGEF39) represent new putative risk factors for SLI. Furthermore, we identified 3'UTR regulatory variants across autism, schizophrenia and bipolar disorder NGS cohorts demonstrating their impact on neurodevelopmental and neuropsychiatric disorders. Our findings show the importance of investigating non-coding regulatory variants when determining risk factors contributing to neurodevelopmental and neuropsychiatric disorders. In the future, integration of such regulatory variation with protein coding changes will be essential for uncovering the genetic causes of complex neurological disorders and the fundamental mechanisms underlying health and disease.Publisher PDFPeer reviewe
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