854 research outputs found

    Analysis of Highly Directive Cavity-Type Configurations Comprising of Low Profile Antennas Covered by Superstrates

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    In this paper we present a technique for designing antenna/superstrate composites to produce enhanced directivities. As a first step, we study the underlying mechanism that governs the performance of theses antennas by studying the canonical problem of a line source in a rectangular waveguide. The above problem is solved by constructing the Green’s function corresponding to the line source in the rectangular guide, one of whose walls is partially reflecting, that is can leak electromagnetic energy into the space external to the guide. The Green’s function for this problem can be constructed by aggregating the multiple reflections from the two walls. Although the above model is only two-dimensional, we show that it can be used to predict the performance of antenna/superstrate composites. We demonstrate this by modeling several highly directive antennas and show that indeed the required characteristics of this type of antennas can be determined from the analysis of the cutoff behavior of the rectangular guide

    ESTUDIO DE LA MERCADOTECNIA EN LA COMPRA Y VENTA DE MIEL: UN ANÃLISIS FACTORIAL

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    This research describes and analyzes the commercial actions being conducted in six groups of producers bee located on the periphery of the state capital of Puebla, Mexico. We study the guidelines that have developed around the marketing as a discipline dedicated to analysis and implications of commercial actions, taking as a hub consumer preferences. There is some use of marketing tools in selling practices carried out by small groups of producers of honey, with the implementation of factor analysis. We found that the actions that develop commercial producers and honey producers are limited to continue with their daily practice of selling what they produce rather than mainstream approach mercadológico to produce what consumers are willing to buy and pay. The orientation of marketing that is focused primarily applied to the production phase, to ensure the acquisition of its product and promoting its sale, even without incorporating current trends show that the needs and preferences of consumers and the market where participating.Honey, marketing, commercial actions, customers., Agribusiness,

    Comprehensive management of obstructive sleep apnea by telemedicine: Clinical improvement and cost-effectiveness of a Virtual Sleep Unit. A randomized controlled trial

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    Introduction: Obstructive sleep apnea (OSA) is a prevalent disease associated with significant morbidity and high healthcare costs. Information and communication technology could offer cost-effective management options. Objectives: To evaluate an out-of-hospital Virtual Sleep Unit (VSU) based on telemedicine to manage all patients with suspected OSA, including those with and without continuous positive airway pressure (CPAP) therapy.Methods: This was an open randomized controlled trial. Patients with suspected OSA were randomized to hospital routine (HR) or VSU groups to compare the clinical improvement and cost-effectiveness in a non-inferiority analysis. Improvement was assessed by changes in the Quebec Sleep Questionnaire (QSQ), EuroQol (EQ-5D and EQ-VAS), and Epworth Sleepiness Scale (ESS). The follow-up was 3 months. Cost-effectiveness was assessed by a Bayesian analysis based on quality-adjusted life-years (QALYs).Results: The HR group (n: 92; 78% OSA, 57% CPAP) compared with the VSU group (n: 94; 83% OSA, 43% CPAP) showed: CPAP compliance was similar in both groups, the QSQ social interactions domain improved significantly more in the HR group whereas the EQ-VAS improved more in the VSU group. Total and OSA-related costs were lower in the VSU group than the HR. The Bayesian cost-effectiveness analysis showed that VSU was cost-effective for a wide range of willingness to pay for QALYs. Conclusions: The VSU offered a cost-effective means of improving QALYs than HR. However, the assessment of its clinical improvement was influenced by the choice of the questionnaire; hence, additional measurements of clinical improvement are needed. Our findings indicate that VSU could help with the management of many patients, irrespective of CPAP use

    Social conditions of becoming homelessness: qualitative analysis of life stories of homeless peoples

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    Background It is increasingly acknowledged that homelessness is a more complex social and public health phenomenon than the absence of a place to live. This view signifies a paradigm shift, from the definition of homelessness in terms of the absence of permanent accommodation, with its focus on pathways out of homelessness through the acquisition and maintenance of permanent housing, to understanding the social context of homelessness and social interventions to prevent it. However, despite evidence of the association between homelessness and social factors, there is very little research that examines the wider social context within which homelessness occurs from the perspective of homeless people themselves. This study aims to examine the stories of homeless people to gain understanding of the social conditions under which homelessness occurs, in order to propose a theoretical explanation for it. Method Twenty-six semi-structured interviews were conducted with homeless people in three centres for homeless people in Cheshire North West of England. Results The analysis revealed that becoming homeless is a process characterised by a progressive waning of resilience capacity to cope with life challenges created by series of adverse incidents in one’s life. The data show that final stage in the process of becoming homeless is complete collapse of relationships with those close to them. Most prominent pattern of behaviours participants often describe as main causes of breakdown of their relationships are: 1. engaging in maladaptive behavioural lifestyle including taking drugs and/or excessive alcohol drinking 2. Being in trouble with people in authorities. Conclusion Homeless people describe the immediate behavioural causes of homelessness, however, the analysis revealed the social and economic conditions within which homelessness occurred. The participants’ descriptions of the social conditions in which were raised and their references to maladaptive behaviours which led to them becoming homeless, led us to conclude that they believe that their social condition affected their life chances: that these conditions were responsible for their low quality of social connections, poor educational attainment, insecure employment and other reduced life opportunities available to them

    Race diversity in dryland maize (Zea mays L.) landraces from southern Nuevo León, Mexico

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    This study was done for reviewing the diversity and distribution of native maize grown at southern Nuevo León, Mexico, in 40 accessions collected in the area. Information obtained was on the production unit and on the ears traits, according to the CONABIO guidelines. In this area maize is usually grown during the Spring-Summer period, and using little technology, without fertilization or pest control. The 40 accessions correspond to seven races and seven interracial crosses. The most frequent maize races were Ratón and Cónico Norteño, especially in dry areas with little rain. Races Celaya, Tablilla de Ocho and Elotes Cónicos found in this study, had not been previously reported; but the Tabloncillo and Olotillo races that had previously been reported were no longer found. Three collections stood out for producing large ears with large kernels, thus having a high yield potential. Native maize harvested in dryland areas might offer advantages to be grown under harsh environments.Objective: To analyze the race diversity and geographic distribution of the native maize landraces currently cropped at southern Nuevo León, México. Design/Methodology/Approach: Data was obtained from 41 accessions which represent the commercial production in the dry land area, where fertilization and pest control are scarcely used. Landraces were classified according to the CONABIO guidelines for ear traits. Results: The measured accessions correspond to seven maize races and to seven interracial crosses. The two most frequent maize races were Ratón and Cónico Norteño, mostly located in the dry areas with less rain. Study Limitations/Implications: Three races, Celaya, Tablilla de Ocho and Elotes Cónicos, had not been previously reported; while two formerly reported races Tabloncillo and Olotillo, were no longer found. This study did not include the grain-colored accessions. Findings/Conclusions: Three collections stood out for producing large ears with large kernels, thus showing a high yield potential. The maize landraces harvested in dryland areas might offer advantages to be grown under harsh environments or be used as gene donors for drought tolerance

    DOCK8 deficiency impairs CD8 T cell survival and function in humans and mice

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    In humans, DOCK8 immunodeficiency syndrome is characterized by severe cutaneous viral infections. Thus, CD8 T cell function may be compromised in the absence of DOCK8. In this study, by analyzing mutant mice and humans, we demonstrate a critical, intrinsic role for DOCK8 in peripheral CD8 T cell survival and function. DOCK8 mutation selectively diminished the abundance of circulating naive CD8 T cells in both species, and in DOCK8-deficient humans, most CD8 T cells displayed an exhausted CD45RA+CCR7? phenotype. Analyses in mice revealed the CD8 T cell abnormalities to be cell autonomous and primarily postthymic. DOCK8 mutant naive CD8 T cells had a shorter lifespan and, upon encounter with antigen on dendritic cells, exhibited poor LFA-1 synaptic polarization and a delay in the first cell division. Although DOCK8 mutant T cells underwent near-normal primary clonal expansion after primary infection with recombinant influenza virus in vivo, they showed greatly reduced memory cell persistence and recall. These findings highlight a key role for DOCK8 in the survival and function of human and mouse CD8 T cells

    Phase III randomized trial of sunitinib versus capecitabine in patients with previously treated HER2-negative advanced breast cancer

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    This multicenter, randomized, open-label phase III trial (planned enrollment: 700 patients) was conducted to test the hypothesis that single-agent sunitinib improves progression-free survival (PFS) compared with capecitabine as treatment for advanced breast cancer (ABC). Patients with HER2-negative ABC that recurred after anthracycline and taxane therapy were randomized (1:1) to sunitinib 37.5 mg/day or capecitabine 1,250 mg/m2 (1,000 mg/m2 in patients >65 years) BID on days 1–14 q3w. The independent data-monitoring committee (DMC) determined during the first interim analysis (238 patients randomized to sunitinib, 244 to capecitabine) that the trial be terminated due to futility in reaching the primary endpoint. No statistical evidence supported the hypothesis that sunitinib improved PFS compared with capecitabine (one-sided P = 0.999). The data indicated that PFS was shorter with sunitinib than capecitabine (median 2.8 vs. 4.2 months, respectively; HR, 1.47; 95% CI, 1.16–1.87; two-sided P = 0.002). Median overall survival (15.3 vs. 24.6 months; HR, 1.17; two-sided P = 0.350) and objective response rates (11 vs. 16%; odds ratio, 0.65; P = 0.109) were numerically inferior with sunitinib versus capecitabine. While no new or unexpected safety findings were reported, sunitinib treatment was associated with higher frequencies and greater severities of many common adverse events (AEs) compared with capecitabine, resulting in more temporary discontinuations due to AEs with sunitinib (66 vs. 51%). The relative dose intensity was lower with sunitinib than capecitabine (73 vs. 95%). Based on these efficacy and safety results, sunitinib should not be used as monotherapy for patients with ABC
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