295 research outputs found

    3D Millimeter-Wave Peer-to-Peer Networks With Boundary Located Destination

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    This letter presents a theoretical analysis for estimating the coverage probability and the average link capacity of an interfered peer-to-peer millimeter-wave communication, when the destination lies at the boundary of a three-dimensional cell. The proposed model provides closed-form expressions for the statistics of the desired and undesired signal powers, by accounting for the impact of directional antenna gains, path-loss attenuation, mid-scale fading, interference, and noise

    New Fourier Transform Approach to the Synthesis of Shaped Patterns by Linear Antenna Arrays

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    A new Fourier Transform (NFT) approach is developed for the synthesis of shaped patterns radiated by linear antenna arrays. The proposed method exploits in an innovative way the FT relation between the source distribution and the radiated pattern. Precisely, the finite dimension of real sources is firstly taken into account by using the sampling theorem to approximate the desired pattern as a band-limited function. It is this step that allows one to obtain an important performance improvement. Then, a continuous source is evaluated from the approximate desired pattern to finally obtain the element excitations. Numerical examples validate the method

    A new accurate approximation of the Gaussian Q-function with relative error less than 1 thousandth in a significant domain

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    The approximations of the Gaussian Q-function found in the literature have been often developed with the goal of obtaining high estimation accuracies in deriving the error probability for digital modulation schemes. Unfortunately, the obtained mathematical expressions are often too complex, even difficultly tractable. A new approximation for the Gaussian Q-function is presented in the form of the standard normal density multiplied by a rational function. The rational function is simply a linear combination of the first 5 integer negative powers of the same term, linear in x, using only 4 decimal constants. In this paper we make some considerations about the significant interval where to consider the Q-function in telecommunication theory. The relative error in absolute value of the given approximation is less than 0.06% in the considered significant interval

    Performance Study of a Class of Irregular Near Capacity Achieving LDPC Codes

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    This paper investigates the performance of a class of irregular low-density parity-check (LDPC) codes through a recently published low complexity upper bound on their beliefpropagation decoding thresholds. Moreover, their performance analysis is carried out through a recently published algorithmic method, presented in Babich et al. 2017 paper. In particular, the class considered is characterized by variable node degree distributions λ(x) of minimum degree i1 > 2: being, in this case, λ0(0) = λ2 = 0, this is useful to design LDPC codes presenting a linear minimum distance growth with the block length with probability 1, as shown in Di et al.'s 2006 paper. These codes unfortunately cannot reach capacity under iterative decoding, since the achievement of capacity requires λ2 ≠ 0. However, in this latter case, the block error probability might converge to a constant, as shown in the aforementioned paper

    Role of the product \u3bb\u2032(0)\u3c1\u2032(1) in determining ldpc code performance

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    The objective of this work is to analyze the importance of the product \u3bb\u2032 (0)\u3c1\u2032 (1) in determining low density parity check (LDPC) code performance, as far as its influence on the weight distribution function and on the decoding thresholds. This analysis is based on the 2006 paper by Di et al., as far as the weight distribution function is concerned, and on the 2018 paper by Vatta et al., regarding the LDPC decoding thresholds. In particular, the first paper Di et al. analyzed the relation between the above mentioned product and the minimum weight of an ensemble of random LDPC codewords, whereas in the second some analytical upper bounds to the LDPC decoding thresholds were determined. In the present work, besides analyzing the performance of an ensemble of LDPC codes through the outcomes of Di et al.\u2019s 2006 paper, we give the relation between one of the upper bounds found in Vatta et al.\u2019s 2018 paper and the above mentioned product \u3bb\u2032 (0)\u3c1\u2032 (1), thus showing its role in also determining an upper bound to LDPC decoding thresholds

    A Simple Blass Matrix Design Strategy for Multibeam Arbitrary Linear Antenna Arrays

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    Multibeam antenna arrays are currently recognized as one of the enabling technologies for the next-generation communication standards. One of the key components of these systems is the beamforming network (BFN) that implements the array element excitations. This article addresses this issue by presenting a novel strategy to realize an analog feeding network, which allows an arbitrary linear array (LA) to radiate multiple arbitrary beams. In particular, an iterative procedure is conceived to design a Blass matrix using an identical directional coupler for all nodes, resulting in a very simple structure suitable for large-scale production. Two applications with arbitrary directions are illustrated as proofs-of-concept for the developed architecture: a dual-beam configuration with a null involving an aperiodic LA, and a four-beam configuration involving a periodic LA. For this second application, the effectiveness of the proposed solution is further verified by full-wave simulations and experimental measurements carried out on a fabricated prototype

    Evidence for replicative mechanism in a CHD7 rearrangement in a patient with CHARGE syndrome

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    Haploinsufficiency of CHD7 (OMIM# 608892) is known to cause CHARGE syndrome (OMIM# 214800). Molecular testing supports a definitive diagnosis in approximately 65-70% of cases. Most CHD7 mutations arise de novo, and no mutations affecting exon-7 have been reported to date. We report on an 8-year-old girl diagnosed with CHARGE syndrome that was referred to our laboratory for comprehensive CHD7 gene screening. Genomic DNA from the subject with a suspected diagnosis of CHARGE was isolated from peripheral blood lymphocytes and comprehensive Sanger sequencing, along with deletion/duplication analysis of the CHD7 gene using multiplex ligation-dependent probe amplification (MLPA), was performed. MLPA analysis identified a reduced single probe signal for exon-7 of the CHD7 gene consistent with potential heterozygous deletion. Long-range PCR breakpoint analysis identified a complex genomic rearrangement (CGR) leading to the deletion of exon-7 and breakpoints consistent with a replicative mechanism such as fork stalling and template switching (FoSTeS) or microhomology-mediated break-induced replication (MMBIR). Taken together this represents the first evidence for a CHD7 intragenic CGR in a patient with CHARGE syndrome leading to what appears to be also the first report of a mutation specifically disrupting exon-7. Although likely rare, CGR may represent an overlooked mechanism in subjects with CHARGE syndrome that can be missed by current sequencing and dosage assays

    Validation and Utilization of a Clinical Next-Generation Sequencing Panel for Selected Cardiovascular Disorders

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    The development of high-throughput technologies such as next-generation sequencing (NGS) has allowed for thousands of DNA loci to be interrogated simultaneously in a fast and economical method for the detection of clinically deleterious variants. Whenever a clinical diagnosis is known, a targeted NGS approach involving the use of disease-specific gene panels can be employed. This approach is often valuable as it allows for a more specific and clinically relevant interpretation of results. Here, we describe the customization, validation, and utilization of a commercially available targeted enrichment platform for the scalability of clinical diagnostic cardiovascular genetic tests, including the design of the gene panels, the technical parameters for the quality assurance and quality control, the customization of the bioinformatics pipeline, and the post-bioinformatics analysis procedures. Regions of poor base coverage were detected and targeted by Sanger sequencing as needed. All panels were successfully validated using genotype-known DNA samples either commercially available or from research subjects previously tested in outside clinical laboratories. In our experience, utilizing several of the sub-panels in a clinical setting with 33 real-life cardiovascular patients, we found that 20% of tests requested were reported to have at least one pathogenic or likely pathogenic variant that could explain the patient phenotype. For each of these patients, the positive results may aid the clinical team and the patients in best developing a disease management plan and in identifying relatives at risk

    Genetic Evaluation of Cardiomyopathy - a Heart Failure Society of America Practice Guideline

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    This guideline describes the approach and expertise needed for the genetic evaluation of cardiomyopathy. First published in 2009 by the Heart Failure Society of America (HFSA), this guidance has now been updated in collaboration with the American College of Medical Genetics and Genomics (ACMG). The writing group, composed of cardiologists and genetics professionals with expertise in adult and pediatric cardiomyopathy, reflects the emergence and increased clinical activity devoted to cardiovascular genetic medicine. The genetic evaluation of cardiomyopathy is a rapidly emerging key clinical priority, as high throughput sequencing is now feasible for clinical testing, and conventional interventions can improve survival, reduce morbidity, and enhance quality of life. Moreover, specific interventions may be guided by genetic analysis. A systematic approach is recommended: always a comprehensive family history; an expert phenotypic evaluation of the proband and at-risk family members to confirm a diagnosis and guide genetic test selection and interpretation; referral to expert centers as needed; genetic testing, with pre- and post-test genetic counseling; and specific guidance as indicated for drug and device therapies. The evaluation of infants and children demands special expertise. The approach to manage secondary and incidental sequence findings as recommended by the ACMG is provided

    The olfactory bulb: an ignored brain structure in the regulation of cardiovascular activity

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    Numerous studies have addressed the participation of the central nervous system in the physiological regulation of blood pressure and in the development and/or maintenance of hypertension. The central nervous system plays a key role in the short-term regulation of blood pressure although recent investigations also support its participation in the long-term modulation. Diverse brain regions and areas like the rostral ventrolateral medulla, the nucleus of the solitary tract, the locus coeruleus, amygdala and hypothalamus are intimately involved in the control of cardiovascular activity. Nevertheless, little is known about the role of the olfactory bulb. This mini review summarizes current knowledge regarding the participation of this telencephalic region in the regulation of cardiovascular activity in physiological and pathophysiological conditions.Numerosos estudios han abordado la participación del sistema nervioso central en la regulación fisiológica de la presión arterial y en el desarrollo y / o mantenimiento de la hipertensión arterial. El sistema nervioso central juega un papel clave en la regulación a corto plazo de la presión arterial, aunque investigaciones recientes apoyan su participación en la modulación a largo plazo. Diversas regiones y áreas del cerebro como la médula ventrolateral rostral, el núcleo del tracto solitario, el locus coeruleus, la amígdala y el hipotálamo están íntimamente involucradas en el control de la actividad cardiovascular. Sin embargo, poco se conoce acerca del papel del bulbo olfatorio. Esta breve revisión resume el conocimiento actual en la participación de esta región telencefálica en la regulación de la actividad cardiovascular en condiciones fisiológicas y fisiopatológicas.Sociedad Argentina de Fisiologí
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