225 research outputs found
Higher Harmonics in Non-Linear Vacuum from QED Effects Without Low Mass Intermediate Particles
We show that in the presence of a slowly rotating strong transverse magnetic
field there is an infinite spectrum of harmonic wave functions due to the
first order QED correction (in ) given by the Euler-Heisenberg
Lagrangian. The frequency shifts are integer multiples of the
magnetic field angular frequency rotation and the several
modes are coupled to the nearest harmonics . This is a new effect
due to QED vacuum fluctuations, not exploit before, that can explain, both
qualitatively and quantatively, the recent experimental results of the PVLAS
collaboration without the need of a low mass intermediate particle, hence
dismiss the recent claim of the discovery of the axion. [Erratum: The PVLAS
signal cannot be explained by this mechanism.]Comment: 4 pages, 1 figure; includes Erratum: The PVLAS signal cannot be
explained by this mechanis
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Production Efficiency of the Tuna fleet of Azores and Madeira: a technical and strategic analysis
Tuna fishery is the main one, in quantity, for both Azores and Madeira Atlantic islands and for Azores it is decisive for the survival of the local tuna canning industry. The main catches are from skipjack and bigeye
tuna species, the last one with TAC restrictions. From a strategic perspective it is important to take in account not only the state of the stocks and the level of the catches but also the technical characteristics
of the fleet and the socioeconomic dimensions of the value chain. Data Envelopment Analysis (DEA) was used to calculate the technical and scale efficiencies of the tuna fleet, both in cross sectional and longitudinal studies. While the type of boats, the technology, the seasonal production pattern and the fishing areas are similar, there are large differences penalizing the Azores fleet that increases when
landings are price valued. The results show the reasons why, that are mainly, for the quantity landings, the scale effect and, for the value landings, the market power of the canning industry. A systemic analysis is then used to integrate different dimensions of the value chain, from the fisheries to the canning industry exports. Since the canned tuna global market is highly concentrated the important local industry press the landings price, so the tuna vessels needs to enlarge its seasonal and spatial production frame to survive
Assessing health literacy among migrants and associated socioeconomic factors
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Perceived need of health care and barriers in access to health services among migrants in Portugal
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Diversification across the Isthmus of Tehuantepec explains the phylogeographic arrangement of the widespread bright-rumped Attila (Attila spadiceus; Tyrannidae) and reveals the existence of two major lineages
We describe the phylogeographic structure of Attila spadiceus, a neotropical bird with 12 recognized subspecies, through the analysis for partial Cytb amplicon region obtained from 11 subspecies. The topology recovered from the analysis indicated the existence of two principal molecular lineages and that the morphological variation underlying the designation of subspecies is not reflected in the mitochondrial gene tree. Based on these findings, we infer that the diversification of A. spadiceus began at the Pleistocene (similar to 1.5 Mya), with the Isthmus of Tehuantepec region as the main factor driving the formation of two molecular lineages, one to the west and the other one to the east of this geographic barrier.Peer reviewe
Central auditory processing and migraine: a controlled study
This study aimed to verify and compare central auditory processing (CAP) performance in migraine with and without aura patients and healthy controls.Forty-one volunteers of both genders, aged between 18 and 40 years, diagnosed with migraine with and without aura by the criteria of the International Classification of Headache Disorders (ICDH-3 beta) and a control group of the same age range and with no headache history, were included. Gaps-in-noise (GIN), Duration Pattern test (DPT) and Dichotic Digits Test (DDT) tests were used to assess central auditory processing performance.The volunteers were divided into 3 groups: Migraine with aura (11), migraine without aura (15), and control group (15), matched by age and schooling. Subjects with aura and without aura performed significantly worse in GIN test for right ear (p = .006), for left ear (p = .005) and for DPT test (p < .001) when compared with controls without headache, however no significant differences were found in the DDT test for the right ear (p = .362) and for the left ear (p = .190).Subjects with migraine performed worsened in auditory gap detection, in the discrimination of short and long duration. They also presented impairment in the physiological mechanism of temporal processing, especially in temporal resolution and temporal ordering when compared with controls. Migraine could be related to an impaired central auditory processing.Research Ethics Committee (CEP 0480.10) - UNIFESP.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo, UNIFESP, Neurol & Neurosurg Dept, DITH, São Paulo, BrazilUniversidade Federal de São Paulo, UNIFESP, Speech Pathol & Audiol Dept, São Paulo, BrazilUniversidade Federal de São Paulo, UNIFESP, Neurol & Neurosurg Dept, DITH, São Paulo, BrazilUniversidade Federal de São Paulo, UNIFESP, Speech Pathol & Audiol Dept, São Paulo, BrazilWeb of Scienc
PRIORIZAÇÃO DOS CRITÉRIOS COMPETITIVOS DAS OPERAÇÕES BASEADO NOS RECURSOS ESTRATÉGICOS
Na literatura da área de estratégia de operações, os critérios competitivos devem ser priorizados tendo como referência a importância desses para os clientes, o desempenho da comparativo aos concorrentes, os trade-offs existentes entre os critérios e a disponibilidades de recursos estratégicos. Entretanto, há uma lacuna na literatura de como fazer essa escolha. Nesse sentido foi realizada a revisão da literatura sobre os temas análise estratégica de operações e teoria baseada em recursos com vistas a contribuir para o entendimento de como os recursos estratégicos se associam com os critérios competitivos. Dessa revisão foi proposto um framework de análise. Esse framework foi pré-testado em duas grandes empresas de Canoas-RS. Durante essa etapa foram realizadas observações diretas nas empresas e entrevistas. Os resultados mostram que um recurso específico pode contribuir com vários critérios competitivos, não havendo uma relação específica entre um recurso estratégico e um critério competitivo em particular e que o framework pode ser utilizado para pesquisas futuras.-----------------------------------------------In the literature of the field of strategy of operations, the competitive criteria must be priorized having as reference the importance of those for the clients, the comparative performance for the competitors, the existing trade-offs between the criteria and the availability of strategic resources. Therefore, there is a lack in the literature in how to make this choice. In this sense, it was carried out a revision of the literature about the themes strategic analysis of operations and theory based on resources aiming to contribute for the understanding of how the strategic resources associate with the competitive criteria. From this revision was proposed a framework of analysis. This framework was pre-tested in two big companies in Canoas, State of Rio Grande do Sul. In the time of this stage, direct observations were carried out in the companies and in the interviews. The results show that a specific resource can contribute with several competitive criteria, not having a specific relation between a strategic resource and a specific competitive criteria and that the framework can be used for future researches.Estratégia, Competitividade, Recursos, Strategy, Competitiveness, Resources, Industrial Organization,
Laccase production by macro-basidiomycetes using Jatropha curcas seed cake as substrate under solid state cultivation.
ANÁLISE COMPARATIVA DA VIABILIDADE DA PRODUÇÃO DE MAMÃO NOS SISTEMAS TRADICIONAL E DE PRODUÇÃO INTEGRADA (PI)
As exigências do mercado internacional de frutas têm colocado aos produtores que desejem acessá-lo a necessidade de adoção do protocolos de Boas Práticas Agrícolas (BPA), cujo objetivo principal é a geração de produtos de qualidade e livres de resíduos químicos. A Produção Integrada de Frutas (PIF) constitui-se em um desses protocolos e sua adoção tem sido incentivada pelo Ministério da Agricultura como forma de elevar os padrões de qualidade do produto nacional, contribuindo para o acesso dos produtores ao mercado externo. Entretanto, a adoção da PIF, além das oportunidades de acesso ao mercado externo e redução de custos com agroquímicos, impõe aos produtores custos adicionais com investimentos em instalações e com processos de certificação. Neste sentido, este trabalho teve como objetivo verificar o efeito da adoção da PIF sobre o retorno dos produtores. Para a consecução da pesquisa, foi necessário escolher uma espécie de fruta para ser analisada em virtude do grande número de espécies produzidas pelo país. Assim, levando-se em consideração aspectos como importância das exportações e o atual estágio de adoção da PIF, a fruta selecionada foi o mamão papaia variedade golden. A realização do trabalho compreendeu, a partir de dados fornecidos por uma empresa produtora de mamão, a elaboração de fluxos de caixa representativos da produção de mamão nos sistemas convencional e integrado, o cálculo de indicadores de viabilidade e a operacionalização de processos de simulação para mensurar o risco envolvido em casa sistema produtivo. Os resultados apontaram pequena vantagem em de retorno e em termos de risco para a produção integrada o que permitiu concluir que a adoção da PIF não garante aos produtores elevação substancial de retornos. -----------------------------------------------The fruit international market’s exigencies have led the producers who wants to have access to it the necessity to adopt Good Agricultural Practices (GAP), whose the principal objective is the production of agricultural products of high quality free of chemical residue. The Integrated Production of Fruit is one of theses protocols and its adoption have received incentive of the Ministry of Agriculture as a form to rise up the standards of quality of the national product, contributing to the access of the producers to the external market. However, the adoption of Integrated Production of Fruit, besides the opportunity of external market access and the reduction of costs with chemical products, imposes additional costs with investments and certifying process. This way, this paper has had as objective to verify the effect of the adoption of the Integrated Production in the producers’ return. To do so, it was necessary to choice one specie of fruit to be analyzed because Brazil produces a lot of species of fruit. Regarding some aspects as the importance of exports and the actual level of Integrated Production in the culture, the select specie was one variety of papaya called golden. Based on some data given by one firm that produces papaya, it was possible to determine representative cash flows of each system of production, Integrated and Conventional. This procedure has permitted the estimation of some viability and risk indicators on both systems. The results aimed small advantage in return and risk terms for the Integrated Production what allowed to conclude that the adoption of Integrated Production of Fruit doesn't guarantee to the producing substantial elevation of returns.Produção Integrada, Boas Práticas Agrícolas e exportações, Integrated production, Good Agricultural Practices and exports, International Relations/Trade,
Photocatalytic Hydrogen Production Of Co(oh)2 Nanoparticle-coated α-fe2o3 Nanorings
The production of hydrogen from water using only a catalyst and solar energy is one of the most challenging and promising outlets for the generation of clean and renewable energy. Semiconductor photocatalysts for solar hydrogen production by water photolysis must employ stable, non-toxic, abundant and inexpensive visible-light absorbers capable of harvesting light photons with adequate potential to reduce water. Here, we show that α-Fe 2O3 can meet these requirements by means of using hydrothermally prepared nanorings. These iron oxide nanoring photocatalysts proved capable of producing hydrogen efficiently without application of an external bias. In addition, Co(OH)2 nanoparticles were shown to be efficient co-catalysts on the nanoring surface by improving the efficiency of hydrogen generation. 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