A channel allocation algorithm for OSA-Enabled IEEE 802.11 WLANs

Channel allocation problem is a major challenge in wireless local area networks (WLANs), especially in dense deployments of access points (APs) where congestion of the unlicensed spectrum bands (i.e., ISM bands) could undermine achieved network performance. This paper analyses the possibility to alleviate congestion of the ISM band by allowing some APs to use additional channels located in licensed bands in an opportunistic manner whenever licensee services (i.e., primary users) are not affected. Availability of these additional channels in licensed bands is assumed not to be the same for all the APs. Based on this assumption, we formulate the problem for the channel assignment as a Binary Linear Programming (BLP) problem, which allows us to obtain an optimal solution despite an elevated execution time. We also develop a heuristic method based on building a Minimum Spanning Tree (MST) graph attending to interference conditions that is able to find nearoptimal solutions with a shorter execution time. Results are provided to assess the benefits of such a proposal under different WLAN deployment situations and primary channel availability conditions.Postprint (published version

Spectrum availability in indoor locations for opportunistic spectrum access in dense urban scenarios

This paper analyses the possibility to exploit opportunistic spectrum access (OSA) for short-range radio communication systems within indoor locations in dense urban areas. In particular, considering the service area of a primary system devoted to providing outdoor coverage in a dense urban scenario, the percentage of indoor locations where the secondary users can reuse the primary frequency band without disturbing the primary system or being disturbed is estimated. The analysis considers heterogeneous path loss models for the primary and secondary systems encompassing the characterization of outdoor, indoor and building penetration losses. Obtained results quantify how aspects like the location of the primary network elements and the considered interference margins to protect primary transmissions impact on the spatial availability of the primary band within the interior of the buildings.Postprint (published version

Influenza vaccination hesitancy in large urban centers in South America : qualitative analysis of confidence, complacency and convenience across risk groups

Influenza vaccination coverage in countries of Latin America is low among priority risk groups, ranging from 5 to 75% among older people. This paper aims to describe and analyze the determinants of influenza vaccination hesitancy through the lens of the 3C model of confidence, complacency and convenience among middle-class, urban risk group populations in Brazil, Chile, Paraguay, Peru, Uruguay, countries in South America with contrasting vaccination coverage. Focus groups were conducted among four risk groups: pregnant women, mothers of children aged =60 years in samples of urban residents. Adults with risk factors expressed the most detailed perceptions about confidence in the vaccine. A wide range of perceptions regarding complacency were expressed across risk groups and countries, with pregnant women and mothers showing greater concerns while convenience had a narrower and generally more positive range of perceptions. Participants from Chile and Paraguay expressed the most contrasts regarding confidence and complacency. Information and communication strategies need to be tailored for risk groups while confidence and complacency should be addressed in synergy

Barreiras e facilitadores da vacinação contra influenza observados por funcionários dos programas nacionais de imunização em países Sul-Americanos com diferentes níveis de cobertura

Influenza is a severe, vaccine-preventable disease. Vaccination programs across Latin American countries show contrasting coverage rates, from 29% in Paraguay to 89% in Brazil. This study explores how national influenza vaccination programs in the chosen South American countries address vaccine confidence and convenience, as well as complacency toward the disease. Barriers and facilitators to influenza vaccination programs in their relation to vaccine hesitancy were observed by documentary analysis and interviews with 38 national immunization program officers in high- (Brazil and Chile) and lowperforming (Paraguay, Peru, and Uruguay) countries. Influenza vaccination policies, financing, purchasing, coordination, and accessibility are considered good or acceptable. National communication strategies focus on vaccine availability during campaigns. In Chile, Paraguay, and Uruguay, anti-vaccine propaganda was mentioned as a problem. Programming and implementation face human resource shortages across most countries. Statistical information, health information systems, and nominal risk-group records are available, with limitations in Peru and Paraguay. Health promotion, supervision, monitoring, and evaluation are perceived as opportunities to address confidence and complacency. Influenza vaccination programs identify and act on most barriers and facilitators affecting influenza vaccine hesitancy via supply-side strategies which mostly address vaccine convenience. Confidence and complacency are insufficiently addressed, except for Uruguay. Programs have the opportunity to develop integral supply and demand-side approaches.La gripe es una enfermedad grave, prevenible mediante vacunas con sus correspondientes programas en países latinoamericanos, informando sobre tasas contrastadas de cobertura, desde el 29% en Paraguay al 89% en Brasil. Este artículo investiga cómo los programas nacionales contra la gripe en países seleccionados de Suramérica abordan la confianza en la vacuna y su conveniencia, así como también la complacencia hacia la enfermedad. Las barreras y facilitadores del programa de vacunación de la gripe, en su relación con la vacilación hacia la vacuna, se observaron mediante análisis documental y entrevistas a 38 a cargo de los programas nacionales de inmunización en países con alto (Brasil y Chile) y bajo desempeño (Paraguay, Perú y Uruguay). Políticas de vacunación contra la gripe, financiamiento, compras coordinación y accesibilidad fueron consideradas como buenas o aceptables. Las estrategias nacionales de comunicación se centran en la disponibilidad de la vacuna durante las campañas. En Chile, Paraguay y Uruguay la propaganda antivacunas fue mencionada como un problema. La planificación e implementación enfrentan escasez de recursos humanos en la mayoría de países a través de la mayoría de países. Los sistemas de información en salud, estadísticas y registros nominales por grupos de riesgo se encuentran disponibles con limitaciones en Perú y Paraguay. La promoción de la salud, supervisión, monitoreo y evaluación son percibidos como oportunidades para abordar la confianza y complacencia. Los programas de vacunación contra la gripe actúan principalmente sobre las barreras y facilitadores que afectan la vacilación a vacunarse mediante estrategias del lado de la demanda, las cuales en su mayor parte van dirigidas a contrarestar la conveniencia. La confianza y complacencia son insuficientemente abordadas en todos los países, excepto en Uruguay. Los programas tienen la oportunidad de desarrollar estrategias que aborden tanto el lado de la oferta como de la demanda.A influenza é uma doença grave, imunoprevenível, para a qual os programas de vacinação nos países latino-americanos apresentam taxas de cobertura contrastantes, desde 29% no Paraguai até 89% no Brasil. O artigo explora de que maneira os programas nacionais de influenza em países selecionados da América do Sul lidam com a confiança e a conveniência da vacina, assim como, a acomodação em relação à doença. As barreiras e facilitadores dos programas de vacinação contra influenza foram observados em relação à hesitação vacinal, através de análise documental e entrevistas com 38 autoridades de programas nacionais de imunização em países com desempenho alto (Brasil e Chile) e baixo (Paraguai, Peru e Uruguai). As políticas de vacinação contra influenza, financiamento da compra de vacinas, coordenação e acessibilidade são consideradas boas ou aceitáveis. As estratégias nacionais de comunicação estão concentradas na disponibilidade durante campanhas. No Chile, Paraguai e Uruguay, a propaganda antivacina foi mencionada enquanto problema. A programação e a implementação enfrentam escassez de recursos humanos na maioria dos países. Dados estatísticos, sistemas de informação em saúde e registros nominais de grupos de risco estão disponíveis, com limitações no Peru e no Paraguai. A promoção da saúde, supervisão, monitoramento e avaliação foram percebidas como oportunidades para tratar da confiança e da acomodação. Os programas de vacinação contra influenza identificam e agem sobre a maioria das barreiras e facilitadores que afetam a hesitação vacinal através de estratégias do lado da oferta, tratando principalmente da conveniência da vacina. A confiança e a acomodação não são tratadas de maneira suficiente, com exceção notável do Uruguai. Os programas têm a oportunidade de desenvolver abordagens que integram os lados da oferta e da procura

Influenza vaccination hesitancy in five countries of South America : confidence, complacency and convenience as determinants of immunization rates

Introduction: Influenza morbidity and mortality are significant in the countries of South America, yet influenza vaccination is as low as 56.7% among pregnant women, reaching 76.7% of adults with chronic diseases. This article measures the relative values for the vaccination hesitancy indicators of confidence, complacency and convenience by risk-groups in urban areas of five countries of South America with contrasting vaccination rates, analyzing their association with sociodemographic variables and self-reported immunization status. Methods: An exit survey was applied to 640 individuals per country in Brazil, Chile, Paraguay, Peru and Uruguay, distributed equally across risk groups of older adults, adults with risk factors, children <=6 and pregnant women. Indicators were constructed for vaccine confidence, complacency and convenience. Analysis of variance and multiple logistic analysis was undertaken. Results: Adults with risk factors are somewhat more confident of the influenza vaccine yet also more complacent. Convenience is higher for mothers of minors. Children and older adults report higher levels of vaccination. The 3Cs are more different across countries than across risk groups, with values for Chile higher for confidence and those for Uruguay the lowest. Complacency is lower in Brazil and higher in Uruguay. Results suggest that confidence and complacency affect vaccination rates across risk groups and countries. Conclusions: Influenza vaccine confidence, complacency and convenience have to be bolstered to improve effective coverage across all risk groups in the urban areas of the countries studied. The role played by country contextual and national vaccination programs has to be further researched in relation to effective coverage of influenza vaccine

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Discurso breve, y juridico por ... Pedro Juan Comes ... Francisco y Esperança Comes ... en el pleyto con Doña Teresa Meseguer viua, y Thomàs Comes ... sobre la succession en los bienes y herencia de Francisco Comes .

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Confirmacion del informe dado en 26 de abril del presente año 1735 por Thomas Comes ... y Doña Theresa Meseguer, viuda, y heredera de Don Francisco Comes ... en el pleyto con ... Pedro Juan Comes ... Francisco Comes ... y Esperanza Comes, hijos de Migue

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A study of aluminium corrosion and inhibition from a conservation perspective

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN023168 / BLDSC - British Library Document Supply CentreGBUnited Kingdo