1,541 research outputs found

    Hybrid analog-digital transmit beamforming for spectrum sharing backhaul networks

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    © 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper deals with the problem of analog-digital transmit beamforming under spectrum sharing constraints for backhaul systems. In contrast to fully digital designs, where the spatial processing is done at baseband unit with all the flexible computational resources of digital processors, analog-digital beamforming schemes require that certain processing is done through analog components, such as phase-shifters or switches. These analog components do not have the same processing flexibility as the digital processor, but on the other hand, they can substantially reduce the cost and complexity of the beamforming solution. This paper presents the joint optimization of the analog and digital parts, which results in a nonconvex, NP-hard, and coupled problem. In order to solve it, an alternating optimization with a penalized convex-concave method is proposed. According to the simulation results, this novel iterative procedure is able to find a solution that behaves close to the fully digital beamforming upper bound scheme.Peer ReviewedPostprint (author's final draft

    Phase only transmit beamforming for spectrum sharing microwave systems

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    This paper deals with the problem of phase-only transmit beamforming in spectrum sharing microwave systems. In contrast to sub-6 GHz schemes, general microwave systems require a large number of antennas due to its huge path loss. As a consequence, digital beamforming needs a large number of computational resources compared to analog beamforming, which only needs a single radio-frequency chain, results the less computational demanding solution. Analog schemes are usually composed by a phase shifter network whose elements transmit at a certain fixed power so that the system designer shall compute the phase values for each element given a set of directions. This approach leads to non-convex quadratic problems where the traditional semidefinite relaxation fails to deliver satisfactory outcomes. In order to solve this, we propose a nonsmooth method that behaves well in several scenarios. Numerical evaluations in different spectrum sharing scenarios, which show the performance of our method, are provided.Peer ReviewedPostprint (author's final draft

    Tobacco: Associated pathologies and causes

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    El tabaco es un producto obtenido de las hojas de "NIcotina Tabacum". Tras ser fabricado, a estas hojas se les añaden sustancias como alquitranes y nicotina entre otras. En el humo, ademas de estas dos sutancias, tambien encontramos monoxido de carbono e irritantes que afectan tanto a las personas que consumen tabaco (fumadores activos) como a las que se encuentran a su alrededor (fumadores pasivos). La sustancia responsable de la adiccion al tabaco es la nicotina. Entre las enfermedades que causa el tabaco encontramos patologias cardiovasculares, respiratorias y cancerosas. Palabras clave: tabaco, tabaquismo, enfermedades tabaco, adiccion tabaco, causas tabaquismoTobacco is a product obtained from the leaves of "NIcotina Tabacum". After being manufactured, these substances are added substances such as tars and nicotine, among others. In the smoke, in addition to these two substances, we also find carbon monoxide and irritants that affect both people who use tobacco (active smokers) and those around them (passive smokers). The substance responsible for the addiction to tobacco is nicotine. Among the diseases caused by tobacco, we find cardiovascular, respiratory and cancerous pathologies

    Effects on the main caregiver of the terminal patient

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    Un paciente se define como terminal cuando sufre una enfermedad en estado avanzado, progresivo e incurable que no responde a tratamiento específico para la curación. Pueden continuar con un tratamiento paliativo, sintomatológico, pero no curativo. La esperanza de vida de estos pacientes es de 6 meses. Los pacientes terminales requieren una serie de cuidados que suele aportar un familiar del paciente. Además, es necesario que el personal sanitario asesore y mire tanto por el paciente como por el cuidador informal, para enseñarle, instruirle y valorar su situación.A patient is defined as terminal when he suffers from an advanced, progressive and incurable disease that does not respond to specific treatment for healing. They can continue with a palliative, symptomatological treatment, but not curative. The life expectancy of these patients is 6 months. Terminal patients require a series of care that is usually provided by a relative of the patient. In addition, it is necessary that health personnel advise and look at both the patient and the informal caregiver, to teach, instruct and assess their situation

    Analysis of PALB2 Gene in BRCA1/BRCA2 Negative Spanish Hereditary Breast/Ovarian Cancer Families with Pancreatic Cancer Cases

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    Background: The PALB2 gene, also known as FANCN, forms a bond and co-localizes with BRCA2 in DNA repair. Germline mutations in PALB2 have been identified in approximately 1% of familial breast cancer and 3-4% of familial pancreatic cancer. The goal of this study was to determine the prevalence of PALB2 mutations in a population of BRCA1/BRCA2 negative breast cancer patients selected from either a personal or family history of pancreatic cancer. Methods: 132 non-BRCA1/BRCA2 breast/ovarian cancer families with at least one pancreatic cancer case were included in the study. PALB2 mutational analysis was performed by direct sequencing of all coding exons and intron/exon boundaries, as well as multiplex ligation-dependent probe amplification. Results: Two PALB2 truncating mutations, the c.1653T>A (p.Tyr551Stop) previously reported, and c.3362del (p.Gly1121ValfsX3) which is a novel frameshift mutation, were identified. Moreover, several PALB2 variants were detected; some of them were predicted as pathological by bioinformatic analysis. Considering truncating mutations, the prevalence rate of our population of BRCA1/2-negative breast cancer patients with pancreatic cancer is 1.5%. Conclusions: The prevalence rate of PALB2 mutations in non-BRCA1/BRCA2 breast/ovarian cancer families, selected from either a personal or family pancreatic cancer history, is similar to that previously described for unselected breast/ovarian cancer families. Future research directed towards identifying other gene(s) involved in the development of breast/pancreatic cancer families is required

    Polymeric foams as the matrix of voltammetric sensors for the detection of catechol, hydroquinone, and their mixtures

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    Producción CientíficaPorous electrodes based on polymethylmethacrylate and graphite foams (PMMA_G_F) have been developed and characterized. Such devices have been successfully used as voltammetric sensors to analyze catechol, hydroquinone, and their mixtures. The presence of pores induces important changes in the oxidation/reduction mechanism of catechol and hydroquinone with respect to the sensing properties observed in nonfoamed PMMA_graphite electrodes (PMMA_G). The electropolymerization processes of catechol or hydroquinone at the electrode surface observed using PMMA_G do not occur at the surface of the foamed PMM_G_F. In addition, the limits of detection observed in foamed electrodes are one order of magnitude lower than the observed in the nonfoamed electrodes. Moreover, foamed electrodes can be used to detect simultaneously both isomers and a remarkable increase in the electrocatalytic properties shown by the foamed samples, produces a decrease in the oxidation potential peak of catechol in presence of hydroquinone, from +0.7 V to +0.3 V. Peak currents increased linearly with concentration of catechol in presence of hydroquinone over the range of 0.37·10−3 M to 1.69·10−3 M with a limit of detection (LOD) of 0.27 mM. These effects demonstrate the advantages obtained by increasing the active surface by means of porous structures.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project AGL2015-67482-R)Junta de Castilla y Leon - Fondo Europeo de Desarrollo Regional (project VA-011U16

    Spectrum sharing backhaul satellite-terrestrial systems via analog beamforming

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    © 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Current satellite and terrestrial backhaul systems are deployed in disjoint frequency bands. This fact precludes an efficient use of the spectrum and limits the evolution of wireless backhauling networks. In this paper, we propose an interference mitigation technique in order to allow the spectrum coexistence between satellite and terrestrial backhaul links. This interference reliever is implemented at the terrestrial backhaul nodes, which are assumed to be equipped with multiple antennas. Due to the large bandwidth and huge number of antennas required in these systems, we consider pure analog beamforming. Precisely, we assume a phased array beamforming configuration so that the terrestrial backhaul node can only reduce the interference by changing the phases of each beamforming weight. Two cases are considered: the 18 and 28 GHz band where transmit and receive beamforming optimization problems shall be tackled, respectively. In both cases, the optimization problem results in a nonconvex problem that we propose to solve via two alternative convex approximation methods. These two approaches are evaluated and they present less than 1 dB array gain loss with respect to the upper bound solution. Finally, the spectral efficiency gains of the proposed spectrum sharing scenarios are validated in numerical simulations.Peer ReviewedPostprint (published version

    Germline ATM mutational analysis in BRCA1/BRCA2 negative hereditary breast cancer families by MALDI-TOF mass spectrometry

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    Biallelic inactivation of ATM gene causes the rare autosomal recessive disorder Ataxia-telangiectasia (A-T). Female relatives of A-T patients have a two-fold higher risk of developing breast cancer (BC) compared with the general population. ATM mutation carrier identification is laborious and expensive, therefore, a more rapid and directed strategy for ATM mutation profiling is needed. We designed a case-control study to determine the prevalence of 32 known ATM mutations causing A-T in Spanish population in 323 BRCA1/BRCA2 negative hereditary breast cancer (HBC) cases and 625 matched Spanish controls. For the detection of the 32 ATM mutations we used the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technique. We identified one patient carrier of the c.8264_8268delATAAG ATM mutation. This mutation was not found in the 625 controls. These results suggest a low frequency of these 32 A-T causing mutations in the HBC cases in our population. Further case-control studies analyzing the entire coding and flanking sequences of the ATM gene are warranted in Spanish BC patients to know its implication in BC predisposition

    Some applications of the bootstrap in Spanish Discards Sampling Scheme

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    Herein we propose a nested boostrap scheme to explore di erent sources of variability in discard data. The proposed tool resamples on trips, hauls within trips and lengthclasess within hauls to include all sources of variability identified in the Spanish DCR sampling program scheme. Megrim (Lepidorhombus wiffiagonis) and Hake (Merluccius merluccius) discard data collected in 2008 from OTB-51 metier operating in ICES Division VI - VII, and Mediterranea DEF-Southern metier operating in the GSA 6S area were considered as case studies. Bootstrap Error and Coeficients of Variation associated to mean discards per trip were obtained and compared with asymptotic estimates. Furthermore, we use the bootstrap to quantify the contribution of the given sources of variability to global variability, and to assess simulated sampling scenarios differing each others in sampling effort. The last application of this method is for detecting outliers in 2008 sampled units (Trips). The good performance of the bootstrap method validates its use to obtain reliable error estimates in further regression and/or classiffication studies on discard data

    Novel Antibacterial and Toughened Carbon-Fibre/Epoxy Composites by the Incorporation of TiO2 Nanoparticles Modified Electrospun Nanofibre Veils

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    The inclusion of electrospun nanofiber veils was revealed as an effective method for enhancing the mechanical properties of fiber-reinforced epoxy resin composites. These veils will eventually allow the incorporation of nanomaterials not only for mechanical reinforcement but also in multifunctional applications. Therefore, this paper investigates the effect of electrospun nanofibrous veils made of polyamide 6 modified with TiO2 nanoparticles on the mechanical properties of a carbon-fiber/epoxy composite. The nanofibers were included in the carbon-fiber/epoxy composite as a single structure. The effect of positioning these veils in different composite positions was investigated. Compared to the reference, the use of unmodified and TiO2 modified veils increased the flexural stress at failure and the fracture toughness of composites. When TiO2 modified veils were incorporated, new antibacterial properties were achieved due to the photocatalytic properties of the veils, widening the application area of these composites.This research is funded by the ELKARTEK Programme, “ACTIMAT”, grupos de investigación del sistema universitario vasco (IT718-13), the Spanish government through the project TEC2015-63838-C3-1-R-OPTONANOSENS and from the Basque government through the project KK-2017/00089-µ4F
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