888 research outputs found

    Functional Bosonization of Non-Relativistic Fermions in (2+1)(2+1) Dimensions

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    We analyze the universality of the bosonization rules in non-relativistic fermionic systems in (2+1)d(2+1)d. We show that, in the case of linear fermionic dispersion relations, a general fermionic theory can be mapped into a gauge theory in such a way that the fermionic density maps into a magnetic flux and the fermionic current maps into a transverse electric field. These are universal rules in the sense that they remain valid whatever the interaction considered. We also show that these rules are universal in the case of non-linear dispersion relations provided we consider only density-density interactions. We apply the functional bosonization formalism to a non-relativistic and non-local massive Thirring-like model and evaluate the spectrum of collective excitations in several limits. In the large mass limit, we are able to exactly calculate this spectrum for arbitrary density-density and current-current interactions. We also analyze the massless case and show that it has no collective excitations for any density-density potential in the Gaussian approximation. Moreover, the presence of current interactions may induce a gapless mode with a linear dispersion relation.Comment: 26 Pages, LaTeX, Final version to appear in International Journal of Modern Physics

    An analysis of landscape fragmentation in the Brazilian Amazon based on deforestation data derived from Landsat imagery.

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    Deforestation in the Brazilian Amazon has produced fragmentation of the largest tropical rain forest in the planet resulting in impacts over biodiversity and the functioning of ecosystems. Most of the deforestation is known to be concentrated near major roads and areas of pioneer colonization, but few studies have quantitatively analyzed patterns and processes of landscape fragmentation associated with this spatial dynamics. In this paper we evaluate the effect of forest clearing based on two landscape metrics - percent cleared and percolation - for areas in the states of Mato Grosso, Pará, and Rondônia where the largest rates of deforestation have been observed. Deforestation data included one data set derived from Landsat MSS imagery for the 1970?s and one based on Landsat TM imagery for 2006. Forest fragments in 2006 within 25-km of areas deforested since 1978 - where a large majority of recent deforestation has been concentrated - were analyzed to assess how landscape fragmentation has evolved following the diffusion of forest clearing within a relatively close neighborhood of the 1978 deforestation. The distribution of deforestation for regular ¼-degree grid cells with different values of percent cleared was estimated as a proxy for the distribution of the equivalent metric based on actual farm limits. The fractions of deforestation for larger categories of percent cleared have increased during the diffusion of forest clearing and a majority of the total 2006 deforestation belonged to areas with less than 50% of forest remnants, taking as reference the Brazilian forest regulations. The diffusion of deforestation has resulted in different patterns of landscape fragmentation based on estimated percolation and we propose an analysis of such patterns based on geographic differences

    CARATkids questionnaire development process

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    Introdução: A asma e a rinite alérgica (ARA) são doenças inflamatórias crónicas das vias aéreas que frequentemente coexistem. O questionário para avaliação do controlo da asma e da rinite alérgica (CARAT) encontra‑se validado para o adulto. O objectivo foi desenvolver o questionário CARATkids para crianças entre os 4 e os 12 anos de idade, com o diagnóstico médico de ARA. Este trabalho pretende descrever o processo do desenvolvimento do questionário. Métodos: O desenvolvimento do questionário foi estruturado em três fases: 1) revisão da literatura sobre questionários pediátricos existentes; 2) realização de reuniões de consenso que permitiu a criação de uma versão preliminar do CARATkids, com duas versões (crianças e pais), composto por 17 itens. Para as crianças, as perguntas foram acompanhadas por ilustrações para cada questão, com formato de resposta dicotómica (sim / não). Para os pais o questionário manteve o formato de CARAT17, com questões com 4 pontos de Likert e outras questões com opção de resposta com escala dicotómica; 3) realização de um estudo transversal através de entrevistas cognitivas efectuadas a 29 crianças e respectivos pais. Resultados: Foram incluídas 29 crianças (11 do sexo feminino) e respectivos pais. A mediana de idades (P25‑P75) foi de 8 (6‑10) anos. As crianças com 4 a 5 anos não sabiam ler o questionário; com 6‑8 eram capazes de ler / compreender as perguntas, embora referindo dificuldades para algumas expressões. As crianças com mais de 9 anos consideraram o questionário muito simples e claro. O grau de concordância entre as crianças e seus pais foi de 61%, tendo ambos considerado as ilustrações muito claras e esclarecedoras quanto aos conceitos subjacentes. Os pais concordaram que a versão destinada aos pais estava muito completa, considerando a versão da criança muito clara e adequada. Consideraram ainda a escala dicotómica como mais apropriada para crianças, em comparação com a escala de Likert do questionário aplicado aos pais. As expressões identificadas como de difícil entendimento foram alteradas. Conclusão: O questionário CARATkids é o primeiro que avalia o controlo da asma e da rinite na criança. Os testes cognitivos demonstraram a sua aplicabilidade dos 6 aos 12 anos de idade.info:eu-repo/semantics/publishedVersio

    Development Process and Cognitive Testing of CARATkids - Control of Allergic Rhinitis and Asthma Test for Children

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    Background: Allergic rhinitis and asthma (ARA) are chronic inflammatory diseases of the airways that often coexist in children. The only tool to assess the ARA control, the Control of Allergic Rhinitis and Asthma Test (CARAT) is to be used by adults. We aimed to develop the Pediatric version of Control of Allergic Rhinitis and Asthma Test (CARATkids) and to test its comprehensibility in children with 4 to 12 years of age. Methods: The questionnaire development included a literature review of pediatric questionnaires on asthma and/or rhinitis control and two consensus meetings of a multidisciplinary group. Cognitive testing was carried out in a cross-sectional qualitative study using cognitive interviews. Results: Four questionnaires to assess asthma and none to assess rhinitis control in children were identified. The multidisciplinary group produced a questionnaire version for children with 17 questions with illustrations and dichotomous (yes/no) response format. The version for caregivers had 4-points and dichotomous scales. Twenty-nine children, 4 to 12 years old, and their caregivers were interviewed. Only children over 6 years old could adequately answer the questionnaire. A few words/expressions were not fully understood by children of 6 to 8 years old. The drawings illustrating the questions were considered helpful by children and caregivers. Caregivers considered the questionnaire complete and clear and preferred dichotomous over the 4-points scales. The proportion of agreement between children and their caregivers was 61%. The words/expressions that were difficult to understand were amended. Conclusion: CARATkids, the first questionnaire to assess a child’s asthma and rhinitis control was developed and its content validity was assured. Cognitive testing showed that CARATKids is well-understood by children 6 to 12 years old. The questionnaire’s measurement properties can now be assessed in a validation study

    Improving the Global Fitting Method on Non-Linear Time Series Analysis

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    In this paper, we are concerned with improving the forecast capabilities of the Global approach to Time Series. We assume that the normal techniques of Global mapping are applied, the noise reduction is performed, etc. Then, using the mathematical foundations behind such approaches, we propose a method that, without a great computational cost, greatly increase the accuracy of the corresponding forecasting

    Perturbing Topological Field Theories

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    The abelian Chern-Simons theory is perturbed by introducing local gauge-invariant interaction terms depending on the curvature. The computation of the correlation function of two Wilson lines for two smooth closed nonintersecting curves is reported up to four loops and is shown to be unaffected by radiative corrections. This result ensures the stability of the linking number of the two curves with respect to the local perturbations which may be added to the Chern-Simons action.Comment: 13 pages, 5 figures, corrected some typo

    Medidas morfométricas da carcaça de cordeiros de diferentes genótipos submetidos a dois sistemas de produção.

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    Resumo: Objetivou-se avaliar a influência do sistema de produção, bem como de diferentes grupos genéticos sobre as características morfométricas da carcaça de cordeiros. Foram observados 24 animais, machos não castrados, das raças ½Dorper x ½SPRD, ½Santa Inês x ½SPRD e ½Somalis x ½SPRD, submetidos à terminação a pasto e em confinamento. Os animais foram abatidos com peso vivo médio de 30 kg. As carcaças foram pesadas e refrigeradas a 4ºC por 24h, quando então foram mensuradas as seguintes medidas morfométricas: comprimento corporal, perímetro torácico, perímetro da perna, comprimento da perna e comprimento interno. O sistema de produção interferiu nas medidas de perímetro da perna e comprimento interno, não havendo diferença significativa (P>0,05) para as demais medidas. Os genótipos estudados não influenciaram na medida de perímetro. As medidas de comprimento da carcaça, perímetro da perna e comprimento interno não diferiram estatisticamente para os mestiços ½Dorper x ½SPRD e ½Santa Inês x ½SPRD, no entanto esses genótipos apresentaram diferença significativa para a raça ½Somalis x ½SPRD nesses parâmetros. O sistema de produção não acarretou mudanças importantes para as medidas morfométricas de comprimento de carcaça, perímetro torácico e comprimento da perna. O mestiço ½Dorper x ½SPRD apresentou as melhores médias para as medidas estudadas. [Morphometric carcass characteristics of lambs of different genotypes under two production systems]. Abstract: Objectified to evaluate the influence of production system, well as of different genetic groups on the morphometric characteristics of the carcass of lambs. 24 animals had been observed, males not castrated, of breeds ½ Dorper x ½ SPRD, ½ Santa Inês x ½ SPRD and ½ Somalis x ½ SPRD, submitted to termination grass and confinement. The animals had been abated with average alive weight 30 kg. The carcasses had been weighed and cooled 4ºC for 24h, when then following morphometric measures had been measured: corporal length, thoracic perimeter, perimeter of leg, length of leg and internal length. The production system intervened with the measures of perimeter of leg and internal length, not having significant difference (P>0.05) for excessively measures. Studied genotypes had not influenced in measure of perimeter. Measures of length of carcass, perimeter of leg and internal length hanot statistical differed for the mestizos ½ Dorper x ½ SPRD and ½ Santa Inês x ½ SPRD, however these genotypes had presented significant difference for the breed ½ Somalis x ½ SPRD in these parameters. The production system does not cause important changes for morphometric measures of carcass length, thoracic perimeter and length of the leg. The mestizo ½ Dorper x ½ SPRD presented best averages for studied measures

    Características qualitativas da carcaça de cordeiros de diferentes genótipos submetidos a dois sistemas de produção.

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    Resumo: No sistema de produção de carne, as características qualitativas da carcaça são de fundamental importância para complementar a avaliação do desempenho animal. Assim, objetivou-se avaliar a influência do sistema de produção, bem como diferentes genótipos sobre as características qualitativas da carcaça de cordeiros. Foram observados 24 animais, machos inteiros, das raças ½Dorper x ½SPRD, ½Santa Inês x ½SPRD e ½Somalis x ½SPRD, submetidos à terminação a pasto e em confinamento. Os animais foram abatidos com peso vivo médio de 30 kg. As carcaças foram pesadas e refrigeradas por 24h, quando foram extraídos os Longissimus dorsi e neles mensurados grau de marmoreio, distribuição e textura da gordura, além da cor e textura da carne. A distribuição da gordura na carcaça não sofreu influência de nenhum tratamento (P>0,05), enquanto que o grau de marmoreio e textura da gordura teve interferência do sistema de produção, assim como a cor da carne. Os genótipos avaliados não diferiram nos atributos de distribuição da gordura, como também na textura e cor da carne. Os cordeiros ½Santa Inês x ½SPRD apresentaram as menores médias para grau de marmoreio e textura da gordura. O mestiço ½Dorper x ½SPRD proporcionou os melhores resultados para os parâmetros qualitativos avaliados nesta pesquisa. [Qualitative characteristics the Carcass Lambs Different Submitted Genotypes Two Systems of Production]. Abstract: In system meat production, qualitative characteristics of carcass are basic importance to complement the evaluation of animal performance. Thus, objectified to evaluate the influence of production system, as well different genotypes on qualitative characteristics carcass of lambs. Twenty four animals had been observed, entire males, breeds ½ Dorper x ½ SPRD, ½ Saint Ines x ½ SPRD and ½ Somalis x ½ SPRD, submitted the termination the grass and in confinement. The animals had been abated with average alive weight of 30 kg. The carcasses had been weighed and cooled for 24h, when they had been extracted Longissimus dorsi and in them measured degree of marbling, distribution and texture of the fat and texture beyond the color and texture of the meat. Distribution of fat in carcass did not suffer influence from no treatment (P>0.05), whereas the degree of marbling and texture of fat had interference of the production system, as well the color of meat. Evaluated genotypes had not differed in distribution attributes of fat, as well as in texture and color of meat. The lambs ½ Saint Ines x ½ SPRD presented the average minors for the marbling attributes and texture of fat. The mixed race ½ Dorper x ½ SPRD provided the best ones resulted for the attributes evaluated in this research
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