94 research outputs found

    A low complexity iterative channel estimation and equalisation scheme for (data-dependent) superimposed training

    Get PDF
    Channel estimation/symbol detection methods based on superimposed training (ST) are known to bemore bandwidth efficient than those based on traditional time-multiplexed training. In this paper we present an iterative version of the ST methodwhere the equalised symbols obtained via ST are used in a second step to improve the channel estimation, approaching the performance of the more recent (and improved) data dependent ST (DDST), but now with less complexity. This iterative ST method (IST) is then compared to a different iterative superimposed training method of Meng and Tugnait (LSST).We show via simulations that the BER of our IST algorithm is very close to that of the LSST but with a reduced computational burden of the order of the channel length. Furthermore, if the LSST iterative approach (originally based on ST) is now implemented using DDST, a faster convergence rate can be achieved for the MSE of the channel estimates

    Synchronisation of the superimposed training method for channel estimation in the presence of DC-offset

    Get PDF
    The superimposed training method estimates the channel from the induced first-order cyclostationary statistics exhibited by the received signal. In this paper, using vector space decomposition, we show that the information needed for training sequence synchronisation, and for DC-offset estimation, can be extracted from the first-order cyclostationary statistics as well. Necessary and sufficient conditions for channel computation and equalisation are derived, when training sequence synchronisation and DC-offset removal are required. The computational burden of the practical implementation of the method presented here is much lighter than for existing algorithms. At the same time, simulation results show that the performance, in terms of the MSE of the channel estimates and BER, is not diminishedwhen compared to these existing algorithms

    Propuesta de políticas administrativas de recursos humanos para el departamento de enfermería de un hospital tipo III de San Felipe

    Get PDF
    This research corresponded with a Feasible Project supported in a descriptive field study which had as its objective to design an Administrative Policy Proposal of Human Resources for the Nursing Department of a Type III Hospital in San Felipe. This study was carried out in the public hospital of Yaracuy State. The population was made up of 19 supervisors belonging to the nursing department. Given that this was a small and finite population, all the individuals it includes were taken for the sample. The data collection was made through a questionnaire instrument structured in three parts; the first referring to demographic data with four questions of simple selection; the second directed at diagnosing the necessity of Administrative Policies of Human Resources for the Nursing Department constituted of 29 closed questions with Yes/No answers, and the third part corresponding to the measure of market, technical and financial feasibility constituted of 15 closed questions with answers options Yes/No. Before applying it, the instrument was subjected to a test of validity of its content by experts where its reliability was determined through a pilot test, applying a statistical procedure to the collected data through the Kuder Richardson 20 test, that allowed the calculation of a coefficient of reliability that resulted in 0.84, recommending the application of the instrument to the sample studied. The diagnosis concluded in the non-existence of written policies and the necessity of designing an Administrative Policy Proposal of Human Resources for the Nursing Department of a Type III Hospital. The market, technical and financial studies showed the feasibility and viability of the proposal. Among the recommendations an implementation of the project was suggested.La presente investigación, correspondió a un Proyecto Factible apoyado en un estudio de campo a nivel descriptivo, que tuvo como objetivo Diseñar una Propuesta de Modelo de Políticas Administrativas de Recursos Humanos para el Departamento de Enfermería de un Hospital Tipo III de San Felipe. Este estudio fue elaborado en un Hospital público del Estado Yaracuy. La población estuvo constituida por 19 supervisores adscritos al Departamento de Enfermería. Dado que las características de esta población fue pequeña y finita, se tomó como muestra a todos los individuos que la integraron. La recolección de los datos se realizó a través de un instrumento tipo cuestionario estructurado en tres partes; la primera referida a los datos demográficos, con cuatro (4) preguntas de selección simple; la segunda, dirigida a diagnosticar la necesidad de Políticas Administrativas de Recursos Humanos para el Departamento de Enfermería, conformada por veintinueve (29) preguntas cerradas con opciones de respuestas SÍ-No, y la tercera parte correspondiente a la medición de factibilidad de mercado, técnico y financiero, conformado por quince preguntas cerradas con opciones de respuesta SÍ-NO. Antes de aplicar el instrumento se sometió a una prueba de validez de contenido por juicios de expertos donde se determinó su confiabilidad mediante una prueba piloto, aplicándose a los datos recabados un procedimiento estadístico mediante la prueba de Kuder Richardson 20, que permitió calcular un coeficiente de confiabilidad que arrojó como resultado 0,84 recomendando la aplicación del instrumento a la muestra en estudio. El diagnostico concluyó en la inexistencia de políticas escritas y la necesidad de diseñar una Propuesta de Políticas Administrativas de Recursos Humanos para el Departamento de Enfermería de un Hospital Tipo III. Los estudios de Mercado, Técnico y Financiero, demostraron la factibilidad y viabilidad de la propuesta. Entre las recomendaciones se sugirió la implementación del proyecto

    Nonlinear screening and percolative transition in a two-dimensional electron liquid

    Full text link
    A novel variational method is proposed for calculating the percolation threshold, the real-space structure, and the thermodynamical compressibility of a disordered two-dimensional electron liquid. Its high accuracy is verified against prior numerical results and newly derived exact asymptotics. The inverse compressibility is shown to have a strongly asymmetric minimum at a density that is approximately the triple of the percolation threshold. This implies that the experimentally observed metal-insulator transition takes place well before the percolation point is reached.Comment: 4 pages, 2 figures. (v2) minor changes (v3) reference added (v4) few more references adde

    Trends and outcome of neoadjuvant treatment for rectal cancer: A retrospective analysis and critical assessment of a 10-year prospective national registry on behalf of the Spanish Rectal Cancer Project

    Get PDF
    Introduction: Preoperative treatment and adequate surgery increase local control in rectal cancer. However, modalities and indications for neoadjuvant treatment may be controversial. Aim of this study was to assess the trends of preoperative treatment and outcomes in patients with rectal cancer included in the Rectal Cancer Registry of the Spanish Associations of Surgeons. Method: This is a STROBE-compliant retrospective analysis of a prospective database. All patients operated on with curative intention included in the Rectal Cancer Registry were included. Analyses were performed to compare the use of neoadjuvant/adjuvant treatment in three timeframes: I)2006–2009; II)2010–2013; III)2014–2017. Survival analyses were run for 3-year survival in timeframes I-II. Results: Out of 14, 391 patients, 8871 (61.6%) received neoadjuvant treatment. Long-course chemo/radiotherapy was the most used approach (79.9%), followed by short-course radiotherapy ± chemotherapy (7.6%). The use of neoadjuvant treatment for cancer of the upper third (15-11 cm) increased over time (31.5%vs 34.5%vs 38.6%, p = 0.0018). The complete regression rate slightly increased over time (15.6% vs 16% vs 18.5%; p = 0.0093); the proportion of patients with involved circumferential resection margins (CRM) went down from 8.2% to 7.3%and 5.5% (p = 0.0004). Neoadjuvant treatment significantly decreased positive CRM in lower third tumors (OR 0.71, 0.59–0.87, Cochrane-Mantel-Haenszel P = 0.0008). Most ypN0 patients also received adjuvant therapy. In MR-defined stage III patients, preoperative treatment was associated with significantly longer local-recurrence-free survival (p < 0.0001), and cancer-specific survival (p < 0.0001). The survival benefit was smaller in upper third cancers. Conclusion: There was an increasing trend and a potential overuse of neoadjuvant treatment in cancer of the upper rectum. Most ypN0 patients received postoperative treatment. Involvement of CRM in lower third tumors was reduced after neoadjuvant treatment. Stage III and MRcN + benefited the most

    On the sensitivity of the HAWC observatory to gamma-ray bursts

    Full text link
    We present the sensitivity of HAWC to Gamma Ray Bursts (GRBs). HAWC is a very high-energy gamma-ray observatory currently under construction in Mexico at an altitude of 4100 m. It will observe atmospheric air showers via the water Cherenkov method. HAWC will consist of 300 large water tanks instrumented with 4 photomultipliers each. HAWC has two data acquisition (DAQ) systems. The main DAQ system reads out coincident signals in the tanks and reconstructs the direction and energy of individual atmospheric showers. The scaler DAQ counts the hits in each photomultiplier tube (PMT) in the detector and searches for a statistical excess over the noise of all PMTs. We show that HAWC has a realistic opportunity to observe the high-energy power law components of GRBs that extend at least up to 30 GeV, as it has been observed by Fermi LAT. The two DAQ systems have an energy threshold that is low enough to observe events similar to GRB 090510 and GRB 090902b with the characteristics observed by Fermi LAT. HAWC will provide information about the high-energy spectra of GRBs which in turn could help to understanding about e-pair attenuation in GRB jets, extragalactic background light absorption, as well as establishing the highest energy to which GRBs accelerate particles

    Associations of autozygosity with a broad range of human phenotypes

    Get PDF
    In many species, the offspring of related parents suffer reduced reproductive success, a phenomenon known as inbreeding depression. In humans, the importance of this effect has remained unclear, partly because reproduction between close relatives is both rare and frequently associated with confounding social factors. Here, using genomic inbreeding coefficients (F-ROH) for >1.4 million individuals, we show that F-ROH is significantly associated (p <0.0005) with apparently deleterious changes in 32 out of 100 traits analysed. These changes are associated with runs of homozygosity (ROH), but not with common variant homozygosity, suggesting that genetic variants associated with inbreeding depression are predominantly rare. The effect on fertility is striking: F-ROH equivalent to the offspring of first cousins is associated with a 55% decrease [95% CI 44-66%] in the odds of having children. Finally, the effects of F-ROH are confirmed within full-sibling pairs, where the variation in F-ROH is independent of all environmental confounding.Peer reviewe

    Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: A systematic analysis for the Global Burden of Disease Study 2015

    Get PDF
    Background: The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods: We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings: Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation: Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding: Bill & Melinda Gates Foundation

    SUPLEMENTO DEL XV CONGRESO INTERNACIONAL DE ACTIVIDAD FÍSICA Y DEPORTE. 17,18 y 19 DE OCTUBRE DEL 2018. ENSENADA, BAJA CALIFORNIA, MÉXICO

    Get PDF
    Compendio, en formato artículo, de los mejores trabajos presentados en el XV CONGRESO INTERNACIONAL DE ACTIVIDAD FÍSICA Y DEPORTE celebrado los días  17,18 y 19 de octubre del 2018 en la Universidad Autónoma de Baja California en la ciudad de Ensenada, Baja California, México:La nutrición en la actividad física y deportiva: alimentos funcionales con nanotecnología, aplicaciones potenciales. González González, K.Y.; Huerta Plaza, B.A.; Amaya Parra, G. (118-130)Perfil antropométrico, físico y hábitos alimentarios en escolares indígenas de Tijuana México. Avendaño Cano, D.L.; Gómez Miranda, L.M.; Aburto Corona, J.A. (131-142)Relación entre el clima de aprendizaje en Educación Física y la percepción de los estudiantes en las competencias del profesorado. Baños, R; Ortiz-Camacho, M.M.; Baena-Extremera, A.; Granero-Gallegos, A.; Machado-Parra, J.P.; Rentería, I.; Acosta, I.; Ramírez, L. (143-153)Valoración de capacidades físicas, composición corporal y consumo de vitaminas en una competencia de Crossfit. Cervantes-Hernández, N.; Hernández Nájera, N.; Carrasco Legleu, C.E.; Candia Lujan, R.; Enríquez Del Castillo, L.A. (154-164)Relación de la actividad física, características antropométricas y VO2máx en jóvenes universitarios: características por género. Enríquez-del Castillo, L.A.; Cervantes-Hernández, N.; Carrasco-Legleu, C.E.; Candia Luján, R. (165-174)Entrenamiento vibratorio de cuerpo completo y sus efectos sobre la composición corporal en jóvenes universitarios. Flores-Chico, B.; Bañuelos-Teres, L.E.; Buendía Lozada, E.R.P. (175-183)Actualización curricular, plan 2016 de la Licenciatura en Cultura Física de la BUAP. Flores-Chico, B.; Flores-Flores, A.; López de La Rosa, LE.; Aguilar-Enríquez, R.I.; Caballero Gómez, JM; Villanueva-Huerta, JA. (184-192)Evaluación psicológica y de la musculatura isquiosural de basquetbolistas universitarias en distintas etapas deportivas. Moranchel-Charros, R.; Martínez-Velázquez, E.S. (193-203)Efecto del ejercicio físico sobre la fuerza, resistencia y riesgo de caída en mujeres adultas. Ortiz Ortiz, M; Espinoza Gutiérrez, R; Gómez Miranda, LM.; Guzmán Gutiérrez, EC.; Calleja Núñez, JJ. (204-212)Desigualdad vs igualdad numérica y su efecto en la técnica de jugadores de fútbol infantil. Vega-Orozco, SI; Gavotto Nogales, OI; Bernal Reyes, F; Horta Gim, MA; Sarabia Sainz, HM. (213-224
    corecore