79 research outputs found

    A boundary layer scaling technique for estimating near-surface wind energy using numerical weather prediction and wind map data

    Get PDF
    A boundary layer scaling (BLS) method for predicting long-term average near-surface wind speeds and power densities was developed in this work. The method was based on the scaling of reference climatological data either from long-term average wind maps or from hourly wind speeds obtained from high-resolution Numerical Weather Prediction (NWP) models, with case study applications from Great Britain. It incorporated a more detailed parameterisation of surface aerodynamics than previous studies and the predicted wind speeds and power densities were validated against observational wind speeds from 124 sites across Great Britain. The BLS model could offer long-term average wind speed predictions using wind map data derived from long-term observational data, with a mean percentage error of 1.5 % which provided an improvement on the commonly used NOABL (Numerical Objective Analysis of Boundary Layer) wind map. The boundary layer scaling of NWP data was not, however, able to improve upon the use of raw NWP data for near surface wind speed predictions. However, the use of NWP data scaled by the BLS model could offer improved power density predictions compared to the use of the reference data sets. Using a vertical scaling of the shape factor of a Weibull distribution fitted to the BLS NWP data, power density predictions with a 1 % mean percentage error were achieved. This provided a significant improvement on the use of a fixed shape factor which must be utilised when only long-term average wind speeds are available from reference wind maps. The work therefore highlights the advantages that use of a BLS model for wind speed and NWP data for power density predictions can offer for small to medium scale wind energy resource assessments, potentially facilitating more robust annual energy production and financial assessments of prospective small and medium scale wind turbine installations

    Hydrogen-bonded Silica Gels Dispersed in a Smectic Liquid Crystal: A Random Field XY System

    Full text link
    The effect on the nematic to smectic-A transition in octylcyanobiphenyl (8CB) due to dispersions of hydrogen-bonded silica (aerosil) particles is characterized with high-resolution x-ray scattering. The particles form weak gels in 8CB creating a quenched disorder that replaces the transition with the growth of short range smectic correlations. The correlations include thermal critical fluctuations that dominate at high temperatures and a second contribution that quantitatively matches the static fluctuations of a random field system and becomes important at low temperatures.Comment: 10 pages, 4 postscript figures as separate file

    Smectic ordering in liquid crystal - aerosil dispersions I. X-ray scattering

    Full text link
    Comprehensive x-ray scattering studies have characterized the smectic ordering of octylcyanobiphenyl (8CB) confined in the hydrogen-bonded silica gels formed by aerosil dispersions. For all densities of aerosil and all measurement temperatures, the correlations remain short range, demonstrating that the disorder imposed by the gels destroys the nematic (N) to smectic-A (SmA) transition. The smectic correlation function contains two distinct contributions. The first has a form identical to that describing the critical thermal fluctuations in pure 8CB near the N-SmA transition, and this term displays a temperature dependence at high temperatures similar to that of the pure liquid crystal. The second term, which is negligible at high temperatures but dominates at low temperatures, has a shape given by the thermal term squared and describes the static fluctuations due to random fields induced by confinement in the gel. The correlation lengths appearing in the thermal and disorder terms are the same and show strong variation with gel density at low temperatures. The temperature dependence of the amplitude of the static fluctuations further suggests that nematic susceptibility become suppressed with increasing quenched disorder. The results overall are well described by a mapping of the liquid crystal-aerosil system into a three dimensional XY model in a random field with disorder strength varying linearly with the aerosil density.Comment: 14 pages, 13 figure

    Use of Pharmacy Banafits Management (PBM) system to describe the profile of antibiotic prescription and purchase

    Get PDF
    No Brasil o PBM (Pharmacy Benefits Management) é de utilização relativamente nova, podendo-se classificá-lo como um sistema de gerenciamento de saúde que administra benefícios na compra e venda de medicamentos. Considerando que o surgimento de bactérias resistentes está relacionado à prescrição inapropriada de antibióticos ou ao uso de antibióticos de baixa atividade, este estudo avaliou se o sistema PBM pode fornecer informações úteis sobre os perfis de prescrição e aquisição de antibióticos de efeitos sistêmicos, a partir da base de dados de uma empresa de PBM brasileira, referente a um grupo formado por 6 525 metalúrgicos de uma empresa da região de Campinas, SP, e seus dependentes, cobrindo o período de janeiro a abril de 2005. Observou-se que 7,7% de todos os medicamentos adquiridos eram antibióticos sistêmicos, numa média 2,4 antibióticos e ao custo de R51,80porreceita.Aamoxicilinafoiofaˊrmacomaisprescritoeem92,7 51,80 por receita. A amoxicilina foi o fármaco mais prescrito e em 92,7% dos casos o usuário adquiriu o medicamento até um dia após a consulta médica. A partir das listas das especialidades farmacêuticas adquiridas (por unidade de venda), dos laboratórios fabricantes, dos antibióticos que compunham cada produto, das datas de emissão das receitas e da dispensação, foi possível concluir que o sistema permite extrair informações relevantes sobre o tema enfocado.Pharmacy Benefits Management (PBM), a system that manages benefits in the purchase and sale of drugs, is of relatively recent implementation in Brazil. Taking into account that the development of bacterial resistance is related to the inadequate prescription of antibiotics or to the use of low activity antibiotics, this study sought to assess the capability of PBM to provide useful information on the profiles of prescription and purchase of systemic antibiotics. The data used for this purpose were collected from the database of a Brazilian PBM company and related to a group of 6 525 metalworkers of a company located in the region of Campinas, SP, and to their dependents, covering the period from January to April 2005. Of the drugs purchased, 7.7% were systemic antibiotics, with a mean of 2.4 antibiotics and a mean cost of R 51.80 per prescription. Amoxicillin was the most prescribed drug. In 92.7% of cases, users purchased the prescribed drug within one day of the medical visit. Based on the lists of purchased pharmaceutical specialties (per retail package), manufacturers, antibiotics present in the composition of each product, prescription dates, and dispensation dates, the system was found capable of providing relevant information on the theme investigated

    Revisión de la literatura integradora acerca de intervenciones de la enfermería volcadas hacia el incremento del autocuidado entre pacientes con insuficiencia cardiaca

    Get PDF
    Objective: to analyze and summarize knowledge concerning critical components of interventions that have been proposed and implemented by nurses with the aim of optimizing self-care by heart failure patients.Methods: PubMed and CINAHL were the electronic databases used to search full peer-reviewed papers, presenting descriptions of nursing interventions directed to patients or to patients and their families and designed to optimize self-care. Forty-two studies were included in the final sample (n=4,799 patients).Results: this review pointed to a variety and complexity of nursing interventions. As self-care encompasses several behaviors, interventions targeted an average of 3.6 behaviors. Educational/counselling activities were combined or not with cognitive behavioral strategies, but only about half of the studies used a theoretical background to guide interventions. Clinical assessment and management were frequently associated with self-care interventions, which varied in number of sessions (1 to 30); length of follow-up (2 weeks to 12 months) and endpoints.Conclusions: these findings may be useful to inform nurses about further research in self-care interventions in order to propose the comparison of different modalities of intervention, the use of theoretical background and the establishment of endpoints to evaluate their effectiveness.Objetivo:analisar e sintetizar o conchecimento relacionado aos componentes críticos das intervençoes que têm, sido propostas e implementadas por enfermeiros(as) com objetivo de optimizar o auto-cuidado de pacientes portadores de insuficiência cardíaca.Método:PubMed e CINAHL foram as bases de dados electrônicas utilizadas para investigar artigos revisados por pares (peer review), apresentando as descrições das intervenções dirigidas ao paciente ou ao paciente e sua familia, visando melhorar o auto-cuidado. Foram incluídos 42 estudos na amostra final (n=4799 pacientes).Resultados:esta revisão apontou variedade e complexidade das intervenções de enfermagem. Como o auto-cuidado envolve diferentes comportamentos, as intervenções visaram em média 3,6 comportamentos. As Atividades de educação e aconselhamento foram combinadas ou não com estratégias cognitivo-comportamentais, mas somente a metade dos estudos utilizaram suporte teórico para guiar as intervenções. A avaliação e o manejo clínico foram frequentemente associados às intervenções de auto-cuidado, as quais variam em número de sessões (1 a 30), duração do seguimento (2 semanas a 12 meses) e desfechos.Conclusão:estes resultados podem ser úteis para guiar os enfermeiros no que se refere à futuros estudos sobre intervenções de auto-cuidado, de maneira a propor a comparação de diferentes modalidades de intervenção, uso de suporte teórico e estabelecimento de desfechos para melhor avaliar sua eficácia.Objetivo:analizar y sintetizar el conocimiento relacionado a componentes críticos de intervenciones que han sido propuestas e implementadas por enfermeros(as) con el objetivo de optimizar el autocuidado entre pacientes con insuficiencia cardiaca.Método:PUBMED y CINAHL han sido las bases de datos electrónicas usadas para investigar artículos revisados por pares (peer review), presentando descripciones de intervenciones destinadas a perfeccionar el autocuidado dirigido al paciente o al paciente y a su familia. Se incluyeron 42 estudios en la muestra final (n=4799 pacientes).Resultados:esta revisión apuntó a una variedad y complejidad de intervenciones de enfermería. Como el autocuidado abarca varios comportamientos, las intervenciones tuvieron como blanco, en media, 3,6 comportamientos. Actividades de educación/consejería fueron combinadas o no con estrategias cognitivo-comportamentales, pero tan solo cerca de la mitad de los estudios tenían aporte teórico para guiar intervenciones. La gestión y la evaluación clínica fueron frecuentemente asociadas a intervenciones de autocuidado, las cuales oscilaron en número de sesiones (1 a 30), duración del seguimiento (2 semanas a 12 meses) y objetivos.Conclusiones:estos resultados pueden ser útiles para informar a las enfermeras acerca de nuevas investigaciones en intervenciones de autocuidado, de modo a proponer la comparación de distintas modalidades de intervención, el uso de un aporte teórico y el establecimiento de objetivos para evaluar su eficacia
    corecore