1,066 research outputs found

    Optimization in VHTS Satellite System Design with Irregular Beam Coverage for Non-Uniform Traffic Distribution

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    Very High Throughput Satellites (VHTS) have a pivotal role in complementing terrestrial networks to increase traffic demand. VHTS systems currently assume a uniform distribution of traffic in the service area, but in a real system, traffic demands are not uniform and are dynamic. A possible solution is to use flexible payloads, but the cost of the design increases considerably. On the other hand, a fixed payload that uses irregular beam coverage depending on traffic demand allows maintaining the cost of a fixed payload while minimizing the error between offered and required capacity. This paper presents a proposal for optimizing irregular beams coverage and beam pattern, minimizing the costs per Gbps in orbit, the Normalized Coverage Error, and Offered Capacity Error per beam. We present the analysis and performance for the case study and compare it with a previous algorithm for a uniform coverage area

    Forward Link Optimization for the Design of VHTS Satellite Networks

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    The concept of geostationary VHTS (Very High Throughput Satellites) is based on multibeam coverage with intensive frequency and polarization reuse, in addition to the use of larger bandwidths in the feeder links, in order to provide high capacity satellite links at a reduced cost per Gbps in orbit. The dimensioning and design of satellite networks based on VHTS imposes the analysis of multiple trade-offs to achieve an optimal solution in terms of cost, capacity, and the figure of merit of the user terminal. In this paper, we propose a new method for sizing VHTS satellite networks based on an analytical expression of the forward link CINR (Carrier-to-Interference-plus-Noise Ratio) that is used to evaluate the trade-off of different combinations of system parameters. The proposed method considers both technical and commercial requirements as inputs, including the constraints to achieve the optimum solution in terms of the user G/T, the number of beams, and the system cost. The cost model includes both satellite and ground segments. Exemplary results are presented with feeder links using Q/V bands, DVB-S2X and transmission methods based on CCM and VCM (Constant and Variable Coding and Modulation, respectively) in two scenarios with different service areas

    Convolutional Neural Networks for Flexible Payload Management in VHTS Systems

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    Very high throughput satellite (VHTS) systems are expected to have a large increase in traffic demand in the near future. However, this increase will not be uniform throughout the service area due to the nonuniform user distribution, and the changing traffic demand during the day. This problem is addressed using flexible payload architectures, enabling the allocation of the payload resources in a flexible manner to meet traffic demand of each beam, leading to dynamic resource management (DRM) approaches. However, DRM adds significant complexity to the VHTS systems, which is why in this article, we are analyzing the use of convolutional neural networks (CNNs) to manage the resources available in flexible payload architectures for DRM. The VHTS system model is first outlined, for introducing the DRM problem statement and the CNN-based solution. A comparison between different payload architectures is performed in terms of DRM response, and the CNN algorithm performance is compared by three other algorithms, previously suggested in the literature to demonstrate the effectiveness of the suggested approach and to examine all the challenges involved

    Repositorios de tesis de posgrado: Capacidad del sistema académico NEA para la generación de depósitos de tesis de acceso libre. 16H315

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    Actividades realizadas durante el período: Exploración Teórica y Documental del Campo Investigativo; Búsqueda, localización y evaluación de bibliografía especializada; Búsqueda, selección y recuperación de documentos institucionales, nacionales e internacionales; Registro, interpretación y aplicación de la documentación descriptiva y explicativa, a la temática en estudio; Encuadre teórico-metodológico del proyect

    Dissimilar Impact of a Mediterranean Diet and Physical Activity on Anthropometric Indices: A Cross-Sectional Study from the ILERVAS Project

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    There is a close relationship between lifestyle behaviors and excess adiposity. Although body mass index (BMI) is the most used approach to estimate excess weight, other anthropometric indices have been developed to measure total body and abdominal adiposity. However, little is known about the impact of physical activity and adherence to a Mediterranean diet on these indices. Here we report the results of a cross-sectional study with 6672 middle-aged subjects with low to moderate cardiovascular risk from the Ilerda Vascular (ILERVAS) project. The participants' adherence to physical activity (International Physical Activity Questionnaire short form) and MedDiet (Mediterranean Diet Adherence Screener) was evaluated. Measures of total adiposity (BMI, Clínica Universidad de Navarra-Body Adiposity Estimator (CUN-BAE), and Deurenberg's formula), central adiposity (waist and neck circumferences, conicity index, waist to height ratio, Bonora's equation, A body adiposity index, and body roundness index), and lean body mass (Hume formula) were assessed. Irrespective of sex, lower indices of physical activity were associated with higher values of total body fat and central adiposity. This result was constant regardless of the indices used to estimate adiposity. However, the association between MedDiet and obesity indices was much less marked and more dependent on sex than that observed for physical activity. Lean body mass was influenced by neither physical activity nor MedDiet adherence. No joint effect between physical activity and MedDiet to lower estimated total or central adiposity indices was shown. In conclusion, physical activity is related to lower obesity indices in a large cohort of middle-aged subjects. MedDiet showed a slight impact on estimated anthropometric indices, with no joint effect when considering both lifestyle variables

    High prevalence of strongyloidiasis in spain : A hospital-based study

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    Strongyloidiasis is a prevailing helminth infection ubiquitous in tropical and subtropical areas, however, seroprevalence data are scarce in migrant populations, particularly for those coming for Asia. This study aims at evaluating the prevalence of S. stercoralis at the hospital level in migrant populations or long term travellers being attended in out-patient and in-patient units as part of a systematic screening implemented in six Spanish hospitals. A cross-sectional study was conducted and systematic screening for S. stercoralis infection using serological tests was offered to all eligible participants. The overall seroprevalence of S. stercoralis was 9.04% (95%CI 7.76-10.31). The seroprevalence of people with a risk of infection acquired in Africa and Latin America was 9.35% (95%CI 7.01-11.69), 9.22% (7.5-10.93), respectively. The number of individuals coming from Asian countries was significantly smaller and the overall prevalence in these countries was 2.9% (95%CI −0.3-6.2). The seroprevalence in units attending potentially immunosuppressed patients was significantly lower (5.64%) compared with other units of the hospital (10.20%) or Tropical diseases units (13.33%) (p < 0.001). We report a hospital-based strongyloidiasis seroprevalence of almost 10% in a mobile population coming from endemic areas suggesting the need of implementing strongyloidiasis screening in hospitalized patients coming from endemic areas, particularly if they are at risk of immunosuppression

    Morbid liver manifestations are intrinsically bound to metabolic syndrome and nutrient intake based on a machine-learning cluster analysis

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    Metabolic syndrome (MetS) is one of the most important medical problems around the world. Identification of patient ' s singular characteristic could help to reduce the clinical impact and facilitate individualized management. This study aimed to categorize MetS patients using phenotypical and clinical variables habitually collected during health check-ups of individuals considered to have high cardiovascular risk. The selected markers to categorize MetS participants included anthropometric variables as well as clinical data, biochemical parameters and prescribed pharmacological treatment. An exploratory factor analysis was carried out with a subsequent hierarchical cluster analysis using the z-scores from factor analysis. The first step identified three different factors. The first was determined by hypercholesterolemia and associated treatments, the second factor exhibited glycemic disorders and accompanying treatments and the third factor was characterized by hepatic enzymes. Subsequently four clusters of patients were identified, where cluster 1 was characterized by glucose disorders and treatments, cluster 2 presented mild MetS, cluster 3 presented exacerbated levels of hepatic enzymes and cluster 4 highlighted cholesterol and its associated treatments Interestingly, the liver status related cluster was characterized by higher protein consumption and cluster 4 with low polyunsaturated fatty acid intake. This research emphasized the potential clinical relevance of hepatic impairments in addition to MetS traditional characterization for precision and personalized management of MetS patients

    Kwapa: Gente del río. Estrategias transmedia de impacto social

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    En este reporte se encuentra toda la documentación del trabajo realizado durante el período de otoño 2022 dentro del proyecto de aplicación profesional Alter Código en el cual se siguió trabajando en la realización del videojuego “A orillas del río” y en la producción del documental de etnoficción “Déjennos pescar”. En el documental etnoficción se tuvo como objetivo principal el rodaje en comunidades cucapá en Baja California, a partir de esto se implementaron diversas estrategias para lograrlo. Como resultado de lo anterior, se abrió un crowdfunding junto con una estrategia de difusión en redes sociales que incluyó, además, la participación en el festival universitario y la producción de stickers para lograr mayor impacto. En el videojuego el objetivo principal consistió en desarrollar una demo jugable cuyo resultado deja definida una dirección concreta para continuar a futuro. Además, permite mostrar las herramientas que se van a implementar como tomar objetos, seleccionar, agarrar e interactuar entre personajes y el entorno. En términos de colaboración se creó un cuadernillo ilustrado para mostrar a niños y adolescentes cucapá y, de este modo, sentar las bases de retroalimentación respecto al desarrollo de la historia y diseño de personajes. Por último, el viaje de producción proveyó de material para seguir desarrollando eldocumental, al mismo tiempo que permitió al equipo de videojuego sentar las bases de una retroalimentación con base en una metodología, desde la perspectiva emic, en la que nuestros colaboradores son co-productores del sentido.ITESO, A.C

    Immunological response against SARS-CoV-2 following full-dose administration of Comirnaty® COVID-19 vaccine in nursing home residents

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    6 páginas, 2 figuras, 3 tablas. Se puede acceder al texto completo de este artículo desde PubMedCentral: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8490129 . Los datos de investigación utilizados en el mismo, se encuentran disponibles en: https://doi.org/10.1016/j.cmi.2021.09.031.Objectives: The current study was aimed at examining SARS-CoV-2 immune responses following two doses of Comirnaty® COVID-19 vaccine among elderly people in nursing homes. Methods: A prospective cohort study in a representative sample from nursing homes in Valencia (n = 881; males: 271, females 610; median age, 86 years) recruited residents using a random one-stage cluster sampling approach. A lateral flow immunochromatography device (LFIC) (OnSite COVID-19 IgG/IgM Rapid Test; CTK BIOTECH, Poway, CA, USA) was used as the front-line test for detecting SARS-CoV-2-Spike (S)-specific antibodies in whole blood obtained using a fingerstick. Residents returning negative LFIC results underwent venipuncture and testing for presence of SARS-CoV-2-S-reactive antibodies and T cells using the Roche Elecsys® Anti-SARS-CoV-2 S (Roche Diagnostics, Pleasanton, CA, USA), the LIAISON® SARS-CoV-2 TrimericS IgG assay (Diasorin S.p.A, Saluggia, Italy) and by flow cytometry, respectively. Results: The SARS-CoV-2-S antibody detection rate in nursing home residents was 99.6% (283/284) and 98.3% (587/597) for SARS-CoV-2 recovered and naïve residents, respectively, within a median of 99 days (range 17-125 days) after full vaccination. Three out of five residents lacking SARS-CoV-2-S antibodies had detectable S-reactive CD8+ and/or CD4+ T cells. In addition, 50/50 and 40/50 participants with detectable SARS-CoV-2 antibodies also had SARS-CoV-2-S-reactive interferon-γ-producing CD4+ and CD8+ T cells, respectively. Discussion: The Comirnaty® COVID-19 vaccine is highly immunogenic in nursing home residents. Keywords: Comirnaty®COVID-19 vaccine; Nursing home residents; SARS-CoV-2; SARS-CoV-2-S antibodies.Ignacio Torres (Río Hortega Contract; CM20/00090), Eliseo Albert (Juan Rodes Contract; JR20/00011) and Estela Gimenez (Juan Rod es Contract, JR18/00053) hold contracts funded by the Health Institute Carlos III (co-financed by the European Regional Development Fund, ERDF/FEDER).Peer reviewe
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