1,205 research outputs found

    A Tale of Two Cycles: Co-Fluctuations Between UK Regions and the Euro Zone

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    We examine the patterns and determinants of business-cycle correlations among eleven UK regions and six euro-zone countries over the 1966-1997 period, using GMM to allow for sampling error in comparing estimated correlations. The British business cycle is found to be persistently out of phase with that of the main euro-zone economies, and the trend is towards lower correlations. We detect only minor cyclical heterogeneity among UK regions. Differences in sectoral specialisation drive some of the asymmetry in GDP fluctuations, but they do not appear significant in explaining the observed reduction in UK-EU business-cycle correlations over time.business cycles; co-fluctuations; UK regions; European monetary union; optimum currency areas

    Spatio-Spectral Vector Beams

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    Increasing the complexity of a light field through the advanced manipulation of its degrees of freedom (DoF) provides new opportunities for fundamental studies and technologies. Correlating polarization with the light's spatial or spectral shape results in so-called spatial or spectral vector beams that are fully polarized and have a spatially or spectrally varying polarization structure. Here, we extend the general idea of vector beams by combining both approaches and structuring a novel state of light in three non-separable DoF's, i.e. space, wavelength, and polarization. We study in detail their complex polarization structure, show that the degree of polarization of the field is only unveiled when the field is narrowly defined in space and wavelength, and demonstrate the analogy to the loss of coherence in non-separable quantum systems. Such light fields allow fundamental studies on the non-separable nature of a classical light field and new technological opportunities, e.g. through applications in imaging or spectroscopy

    High-order aberrations of vortex constellations

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    When reflected from an interface, a laser beam generally drifts and tilts away from the path predicted by ray optics, an intriguing consequence of its finite transverse extent. Such beam shifts manifest more dramatically for structured light fields, and in particular for optical vortices. Upon reflection, a field containing a high-order optical vortex is expected to experience not only geometrical shifts, but an additional splitting of its high-order vortex into a constellation of unit-charge vortices, a phenomenon known as topological aberration. In this article, we report on the first direct observation of the topological aberration effect, measured through the transformation of a vortex constellation upon reflection. We develop a general theoretical framework to study topological aberrations in terms of the elementary symmetric polynomials of the coordinates of a vortex constellation, a mathematical abstraction which we prove to be the physical quantity of interest. Using this approach, we are able to verify experimentally the aberration of constellations of up to three vortices reflected from a thin metallic film. Our work not only deepens the understanding of the reflection of naturally occurring structured light fields such as vortex constellations but also sets forth a potential method for studying the interaction of twisted light fields with matter.Comment: Main: 6 pages, 3 figures. Supplementary: 6 pages, 2 figure

    Iniqüidades sociais na saúde e nutrição de crianças em países de renda baixa e média

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    OBJECTIVE: To describe the effects of social inequities on the health and nutrition of children in low and middle income countries. METHODS: We reviewed existing data on socioeconomic disparities within-countries relative to the use of services, nutritional status, morbidity, and mortality. A conceptual framework including five major hierarchical categories affecting inequities was adopted: socioeconomic context and position, differential exposure, differential vulnerability, differential health outcomes, and differential consequences. The search of the PubMed database since 1990 identified 244 articles related to the theme. Results were also analyzed from almost 100 recent national surveys, including Demographic Health Surveys and the UNICEF Multiple Indicator Cluster Surveys. RESULTS: Children from poor families are more likely, relative to those from better-off families, to be exposed to pathogenic agents; once they are exposed, they are more likely to become ill because of their lower resistance and lower coverage with preventive interventions. Once they become ill, they are less likely to have access to health services and the quality of these services is likely to be lower, with less access to life-saving treatments. As a consequence, children from poor family have higher mortality rates and are more likely to be undernourished. CONCLUSIONS: Except for child obesity and inadequate breastfeeding practices, all the other adverse conditions analyzed were more prevalent in children from less well-off families. Careful documentation of the multiple levels of determination of socioeconomic inequities in child health is essential for understanding the nature of this problem and for establishing interventions that can reduce these differences.OBJETIVO: Describir el efecto de las iniquidades sociales sobre la nutrición y salud de niños de países de renta baja y media. MÉTODOS: Fueron revisadas informaciones disponibles sobre disparidades socioeconómicas intra-países, relativas al uso de servicios de salud, estado nutricional, morbilidad y mortalidad. Se adoptó un modelo conceptual con cinco categorías jerárquicas en la producción de inequidades: contexto y posición socioeconómica, diferencias en la exposición, en la vulnerabilidad, en los hechos de salud y en las consecuencias. En investigación realizada en la base PubMed, en el período de 1990-2007 fueron encontrados 244 artículos relacionados al tema. Fueron también analizados los resultados de cerca de 100 pesquisas de ámbito nacional recientes, incluyendo Pesquisas Nacionales de Demografía y Salud y Pesquisas por Conglomerados de Múltiples Indicadores, del Fondo de las Naciones Unidas para la Infancia. RESULTADOS: Niños de familias pobres, en comparación con aquellas de familias más ricas, son más susceptibles a la exposición a agentes patogénicos; una vez expuestas, tienen un riesgo aumentado de enfermar, debido a su menor resistencia y menor cobertura de medidas preventivas. Una vez que se toman enfermos, tienen menor acceso a servicios de salud, la calidad de los servicios que logran utilizar tiende a ser inferior, con menor acceso a tratamientos médicos que garanticen su sobrevivencia. Como consecuencia, niños de familias más pobres presentan mayores tasas de mortalidad y mayor riesgo de ser subnutridas. CONCLUSIONES: Excepto obesidad infantil y prácticas inadecuadas de amamantamiento, todas las otras condiciones adversas analizadas tuvieron mayor prevalencia entre los niños de familias menos favorecidas. La documentación cuidadosa de los múltiples niveles de determinantes de las inequidades socioeconómicas en salud infantil es esencial para el entendimiento de la naturaleza del problema, y para el establecimiento de intervenciones que puedan reducir estas diferencias.OBJETIVO: Descrever o efeito das iniqüidades sociais sobre a nutrição e saúde de crianças de países de renda baixa e média. MÉTODOS: Foram revisadas informações disponíveis sobre disparidades socioeconômicas intra-países, relativas a uso de serviços de saúde, estado nutricional, morbidade e mortalidade. Adotou-se um modelo conceitual com cinco categorias hierárquicas na produção de iniqüidades: contexto e posição socioeconômica, diferenças na exposição, na vulnerabilidade, nos desfechos de saúde e nas conseqüências. Em pesquisa realizada na base PubMed, no período de 1990-2007 foram encontrados 244 artigos relacionados ao tema. Foram também analisados os resultados de cerca de 100 inquéritos de âmbito nacional recentes, incluindo Pesquisas Nacionais de Demografia e Saúde e Inquéritos por Conglomerados de Múltiplos Indicadores, do Fundo das Nações Unidas para a Infância. RESULTADOS: Crianças de famílias pobres, em comparação com aquelas de famílias mais ricas, são mais suscetíveis à exposição a agentes patogênicos; uma vez expostas, têm um risco aumentado de adoecer, devido à sua menor resistência e menor cobertura de medidas preventivas. Uma vez que se tornam doentes, têm menor acesso a serviços de saúde, a qualidade dos serviços que logram utilizar tende a ser inferior, com menor acesso a tratamentos médicos que garantam sua sobrevivência. Como conseqüência, crianças de famílias mais pobres apresentam maiores taxas de mortalidade e maior risco de serem subnutridas. CONCLUSÕES: Exceto obesidade infantil e práticas inadequadas de aleitamento materno, todas as outras condições adversas analisadas tiveram maior prevalência entre as crianças de famílias menos favorecidas. A documentação cuidadosa dos múltiplos níveis de determinantes das iniqüidades socioeconômicas em saúde infantil é essencial para o entendimento da natureza do problema, e para o estabelecimento de intervenções que possam reduzir estas diferenças

    Revealing the drivers of parasite community assembly: using avian haemosporidians to model global dynamics of parasite species turnover

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    Why do some regions share more or fewer species than others? Community assembly relies on the ability of individuals to disperse, colonize and thrive in new regions. Therefore, many distinct factors, such as geographic distance and environmental features, can determine the odds of a species colonizing a new environment. For parasites, host community composition (i.e. resources) also plays a key role in their ability to colonize a new environment as they rely on their hosts to complete their life cycle. Thus, variation in host community composition and environmental conditions should determine parasite turnover among regions. Here, we explored the global drivers of parasite turnover using avian malaria and malaria-like (haemosporidian) parasites. We compiled global databases on avian haemosporidian lineages distributions, environmental conditions, avian species distributions and functional traits, and ran generalized dissimilarity models to uncover the main drivers of parasite turnover. We demonstrated that haemosporidian parasite turnover is mainly driven by geographic distance followed by host functional traits, environmental conditions and host distributions. The main host functional traits associated with high parasite turnover were the predominance of resident (i.e. non-migratory) species and strong territoriality, while the most important climatic drivers of haemosporidian turnover were mean temperature and temperature seasonality. Overall, we established the importance of geographic distance as a key predictor of ecological dissimilarity and showed that host resources influence parasite turnover more strongly than environmental conditions. We also evidenced that parasite turnover is most pronounced among tropical and less interconnected regions (i.e. regions with mostly territorial and non-migratory hosts). Our findings provide a robust foundation for the prediction of avian pathogen spread and the emergence of infectious diseases.Fil: de Angeli Dutra, Daniela. University of Otago; Nueva ZelandaFil: Barros Pereira Pinheiro, Rafael. Universidade Estadual de Campinas; BrasilFil: Fecchio, Alan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónica. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigación Esquel de Montaña y Estepa Patagónica; ArgentinaFil: Poulin, Robert. University of Otago; Nueva Zeland

    Developing urban design discourse beyond the critical point: the case of Sao Paulo

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    This paper discusses some environmental challenges confronting humanity over the next fifty years by considering conditions that have emerged over the previous fifty years in one of the world's 'megacities'. Problems of homelessness & poor social housing conditions, ‘visual pollution’ and urban water, are linked through a case study about the City of São Paulo. From the combined perspective of philosophy, the arts, design and engineering, the paper seeks to explain how such diverse disciplinary concerns can be unified through urban design and address a situation that is well beyond what has been called 'the critical point'. Some approaches to urban design are recommended that provide typologies of products and processes to address such challenges

    Aspectos energéticos da teoria cinética dos gases

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    Neste artigo, discutem-se aspectos energéticos relacionados à Teoria Cinética dos Gases (TCG). Trata-se de um estudo de revisão bibliográfica. Os dados foram coletados através do levantamento das fontes, por meio de textos técnicos, publicações científicas e livros didáticos. Através da interpretação energética da TCG foi possível discutir a rota para o equilíbrio térmico, a transferência de partículas entre níveis de energia devido à variação na temperatura e também demonstrar a distribuição de Maxwell-Boltzmann-Gibbs. Além disso, notou-se que a visão energética das TCG fornece uma ponte entre colisões e transações financeiras. Conclui-se que a abordagem energética da TCG possui importância crucial para o entendimento dos fundamentos da Física Térmica, sobretudo no Ensino Médio, onde estes estudos possuem uma demanda significativa na disciplina de Físic
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