863 resultados para Block-fading (BF) channel
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Trp(Nps)-Lys-NH2 derivatives, bearing alkyl or guanidine groups either at the N-terminus or on the Lys side-chain or at both positions were conveniently prepared on solid-phase and evaluated as TRPV1 channel antagonists.
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Key factors that provide context for the state's Maternal and Child Health (MCH) annual report and state plan are highlighted in this overview. This section briefly outlines Iowa's demographics, population changes, economic indicators and significant public initiatives. Major strategic planning efforts affecting development of program activities are also identified.
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Title V of the Social Security Act is the longest-standing public health legislation in American history. Enacted in 1935, Title V is a federal-state partnership that promotes and improves maternal and child health (MCH). According to each state’s unique needs, Title V supports a spectrum of services, from infrastructure building services like quality assurance and policy development, to gap-filling direct health care services. Title V resources are directed towards MCH priority populations: pregnant women, mothers, infants, women of reproductive years, children and adolescents and children and youth with special health care needs.
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The study area. located north of Konva (Central Turkey), is composed of Silurian to Cretaceous metamorphosed rocks. The lower unit of the oldest formation (Silurian-Early Permian) is mostly made up of Silurian-Early Carboniferous metacarbonates. These rocks pass laterally and vertically to Devonian-Early Permian series having continental margin, shallow water and pelagic characteristics. They are intruded or juxtaposed to different kinds of metamagmatic rocks. which show MORB. continental arc and within plate characteristics. The Palaeozoic units are covered unconformably by Triassic-Cretaceous metasedimentary units. All these rocks are overthrusted by Mesozoic ophiolites. The Palaeozoic sequence can be seen as a northern Palaeotethys passive, then active margin. The northward subduction of the Palaeotethys ocean during the Carboniferous-Triassic times, induced the development of a magmatic arc and fore-arc sequence (Carboniferous-Permian). Before the Early Triassic (?Late Permian) time. the fore-arc sequence was uplifted above sea level and eroded. The Triassic sequences are regarded as marking the onset of back-arc opening and detachment of the Anatolian Konya block from the active Eurasian margin. Finally. a suture zone formed during the Carman between the Konya region and the Menderes-Tauride Cimmerian block due to the closing of Palaeotethvs. This geodynamic evolution can be correlated with the evolution of the Karaburun sequence in western Turkey.
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When certain control parameters of nervous cell models are varied, complex bifurcation structures develop in which the dynamical behaviors available appear classified in blocks, according to criteria of dynamical likelihood. This block structured dynamics may be a clue to understand how activated neurons encode information by firing spike trains of their action potentials.
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The epithelial sodium channel ENaC is physiologically important in the kidney for the regulation of the extracellular fluid volume, and in the lungs for the maintenance of the appropriate airway surface liquid volume that lines the pulmonary epithelium. Besides the regulation of ENaC by hormones, intracellular factors such as Na(+) ions, pH, or Ca(2+) are responsible for fast adaptive responses of ENaC activity to changes in the intracellular milieu. In this study, we show that ENaC is rapidly and reversibly inhibited by internal sulfhydryl-reactive molecules such as methanethiosulfonate derivatives of different sizes, the metal cations Cd(2+) and Zn(2+), or copper(II) phenanthroline, a mild oxidizing agent that promotes the formation of disulfide bonds. At the single channel level, these agents applied intracellularly induce the appearance of long channel closures, suggesting an effect on ENaC gating. The intracellular reducing agent dithiothreitol fully reverses the rundown of ENaC activity in inside-out patches. Our observations suggest that changes in intracellular redox potential modulate ENaC activity and may regulate ENaC-mediated Na(+) transport in epithelia. Finally, substitution experiments reveal that multiple cysteine residues in the amino and carboxyl termini of ENaC subunits are responsible for this thiol-mediated inhibition of ENaC.
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It is well established that cancer cells can recruit CD11b(+) myeloid cells to promote tumor angiogenesis and tumor growth. Increasing interest has emerged on the identification of subpopulations of tumor-infiltrating CD11b(+) myeloid cells using flow cytometry techniques. In the literature, however, discrepancies exist on the phenotype of these cells (Coffelt et al., Am J Pathol 2010;176:1564-1576). Since flow cytometry analysis requires particular precautions for accurate sample preparation and trustable data acquisition, analysis, and interpretation, some discrepancies might be due to technical reasons rather than biological grounds. We used the syngenic orthotopic 4T1 mammary tumor model in immunocompetent BALB/c mice to analyze and compare the phenotype of CD11b(+) myeloid cells isolated from peripheral blood and from tumors, using six-color flow cytometry. We report here that the nonspecific antibody binding through Fc receptors, the presence of dead cells and cell doublets in tumor-derived samples concur to generate artifacts in the phenotype of tumor-infiltrating CD11b(+) subpopulations. We show that the heterogeneity of tumor-infiltrating CD11b(+) subpopulations analyzed without particular precautions was greatly reduced upon Fc block treatment, dead cells, and cell doublets exclusion. Phenotyping of tumor-infiltrating CD11b(+) cells was particularly sensitive to these parameters compared to circulating CD11b(+) cells. Taken together, our results identify Fc block treatment, dead cells, and cell doublets exclusion as simple but crucial steps for the proper analysis of tumor-infiltrating CD11b(+) cell populations.
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We report a case of neonatal lupus erythematosus (NLE) with congenital heart block and severe myocardial failure, which was followed from the 25th week of gestation because of fetal bradycardia. The child was delivered at the 37th week of gestation by elective cesarean section because of echocardiographically documented heart enlargement, pericardial effusion and moderate insufficiency of the mitral and tricuspid valves. In spite of immediate pacing, intubation and supportive treatment, the newborn developed progressive heart failure. Echocardiography showed endocarditis of the mitral valve and diffuse myocarditis. The heart failure resolved under steroid treatment. Our experience supports the early use of steroids in treating myocarditis due to NLE. Intrauterine steroid treatment in the presence of fetal hydrops and congenital heart block is discussed.
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In this paper, we investigate the average andoutage performance of spatial multiplexing multiple-input multiple-output (MIMO) systems with channel state information at both sides of the link. Such systems result, for example, from exploiting the channel eigenmodes in multiantenna systems. Dueto the complexity of obtaining the exact expression for the average bit error rate (BER) and the outage probability, we deriveapproximations in the high signal-to-noise ratio (SNR) regime assuming an uncorrelated Rayleigh flat-fading channel. Moreexactly, capitalizing on previous work by Wang and Giannakis, the average BER and outage probability versus SNR curves ofspatial multiplexing MIMO systems are characterized in terms of two key parameters: the array gain and the diversity gain. Finally, these results are applied to analyze the performance of a variety of linear MIMO transceiver designs available in the literature.
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This paper presents a Bayesian approach to the design of transmit prefiltering matrices in closed-loop schemes robust to channel estimation errors. The algorithms are derived for a multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system. Two different optimizationcriteria are analyzed: the minimization of the mean square error and the minimization of the bit error rate. In both cases, the transmitter design is based on the singular value decomposition (SVD) of the conditional mean of the channel response, given the channel estimate. The performance of the proposed algorithms is analyzed,and their relationship with existing algorithms is indicated. As withother previously proposed solutions, the minimum bit error rate algorithmconverges to the open-loop transmission scheme for very poor CSI estimates.
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Broadcast transmission mode in ad hoc networks is critical to manage multihop routing or providing medium accesscontrol (MAC)-layer fairness. In this paper, it is shown that ahigher capacity to exchange information among neighbors may beobtained through a physical-MAC cross-layer design of the broadcastprotocol exploiting signal separation principles. Coherentdetection and separation of contending nodes is possible throughtraining sequences which are selected at random from a reducedset. Guidelines for the design of this set are derived for a lowimpact on the network performance and the receiver complexity.
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This paper analyzes the asymptotic performance of maximum likelihood (ML) channel estimation algorithms in wideband code division multiple access (WCDMA) scenarios. We concentrate on systems with periodic spreading sequences (period larger than or equal to the symbol span) where the transmitted signal contains a code division multiplexed pilot for channel estimation purposes. First, the asymptotic covariances of the training-only, semi-blind conditional maximum likelihood (CML) and semi-blind Gaussian maximum likelihood (GML) channelestimators are derived. Then, these formulas are further simplified assuming randomized spreading and training sequences under the approximation of high spreading factors and high number of codes. The results provide a useful tool to describe the performance of the channel estimators as a function of basicsystem parameters such as number of codes, spreading factors, or traffic to training power ratio.