11,565 research outputs found

    Improving the Knowledge on Seismogenic Sources in the Lower Tagus Valley for Seismic Hazard Purposes

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    The Lower Tagus Valley, that includes the metropolitan area of Lisbon, has been struck by several earthquakes which produced significant material damage and loss of lives. Their exact location remains unknown. Our goal is to shed some light into the seismogenic sources in the area using seismic reflection and geological data. In areas with no seismic coverage, potential-field data interpretation was carried out. Seismicity was overlaid to the potential seismogenic structures and high-resolution data was acquired in order to confirm which structures have been active into the Quaternary. Three major fault-zones affecting the Neogene were identified: V. F. Xira, Samora-Alcochete and Pinhal Novo. For the first fault, strong evidences suggest it is active. The other two fault-zones and other structures previously unknown can be correlated with several epicentres. Empirical relationships between maximum moment magnitude and fault area indicate that MW > 6.5 earthquakes can be expected for the larger structures

    Fault accommodation controller under Markovian jump linear systems with asynchronous modes

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    We tackle the fault accommodation control (FAC) in the Markovian jump linear system (MJLS) framework for the discrete-time domain, under the assumption that it is not possible to access the Markov chain mode. This premise brings some challenges since the controllers are no longer allowed to depend on the Markov chain, meaning that there is an asynchronism between the system and the controller modes. To tackle this issue, a hidden Markov chain ((Formula presented.), (Formula presented.)) is used where θ(k) denotes the Markov chain mode, and (Formula presented.) denotes the estimated mode. The main novelty of this work is the design of H∞ and H2 FAC under the MJLS framework considering partial observation of the Markov chain. Both designs are obtained via bilinear matrix inequalities optimization problems, which are solved using coordinate descent algorithm. As secondary results, we present simulations using a two-degree of freedom serial flexible joint robot to illustrate the viability of the proposed approach

    Gain-Scheduled Fault Detection Filter For Discrete-time LPV Systems

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    The present work investigates a fault detection problem using a gain-scheduled filter for discrete-time Linear Parameter Varying systems. We assume that we cannot directly measure the scheduling parameter but, instead, it is estimated. On the one hand, this assumption imposes the challenge that the fault detection filter should perform properly even when using an inexact parameter. On the other, it avoids the burden associated with designing a complex estimation process for this parameter. We propose three design approaches: the H2{\mathcal {H}_{2}} , H{\mathcal {H}_{\infty }} , and mixed H2/H{\mathcal {H}_{2}} / {\mathcal {H}_{\infty }} gain-scheduled Fault Detection Filters designed via Linear Matrix Inequalities. We also provide numerical simulations to illustrate the applicability and performance of the proposed novel methods

    Volatilização de amônia de fontes nitrogenadas em feijoeiro irrigado no sistema plantio direto.

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    O objetivo deste estudo foi avaliar as perdas de N por volatilização de NH3, em diferentes fontes de nitrogênio aplicadas no feijoeiro comum irrigado, cultivado em Latossolo de Cerrado sobre palhada de braquiária em sistema plantio direto.Conpeex 2010

    Seca do frutos do açaizeiro no estado do Pará.

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    Objetivou-se relatar a seca dos frutos do açaizeiro, em três diferentes municípios do estado do Pará, safra 2014. Amostras de frutos secos dos municípios de Abaetetuba e Belém foram analisadas no Laboratório de Fitopatologia da Embrapa Amazônia Oriental e do município de Igarapé Mirim no Laboratório de Microbiologia de Alimentos do IFPA - Campus Castanhal, respectivamente. Os frutos foram incubados em caixas do tipo 'gerbox' à temperatura de 25±2 ºC e fotoperíodo de 12h, durante até 72h. Procederam-se isolamentos diretos em placas de Petri com meio de cultura ágar-água a 20%. Frutos com esporulação do patógeno foram utilizados para o isolamento direto, sem incubação prévia, e analisados em microscópios estereoscópio e de luz. Após três dias de incubação, discos de micélios foram repicados para o meio de cultura batata dextrose ágar (BDA). Observaram-se crescimento micelial branco e, após 10 dias de incubação, verificou-se a formação de colônias de coloração acinzentada nas placas de Petri. Foram confeccionadas lâminas para microscopia de luz. Verificaram-se a presença de hifas septadas e ramificadas e intensa produção de conídios unicelulares hialinos, em ambas as amostras. A doença seca dos frutos foi confirmada em amostras oriundas dos municípios de Abaetetuba, Belém e Igarapé Mirim, com associação do fungo Colletotrichum spp

    IL-6 and TNF-alpha polymorphisms in portuguese psoriatic patients

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    Introduction: Cytokines regulate the growth, function and differentiation of cells and help to steer immune response and inflammation. In this study we focused our attention in two proinflammatory cytokines: IL-6 and TNFa. It is known that their overexpression is responsible for initiation, maintenance and recurrence of skin lesions in psoriatic patients. Therefore, it is important to investigate genetic biomarkers with functional effects in the genes of those cytokines that could help to predict the severity of Psoriasis. Objectives: To investigate the hypothesis that allelic variants in IL-6 and TNF-a genes are a risk factor for the developing of severe Psoriasis. Materials and Methods: A cohort of 178 (74 females, 104 males) psoriatic patients with severe plaque type psoriasis [according to the Psoriasis Area and Severity Index (PASI)] and 206 healthy individuals were selected. Several polymorphisms in the IL-6 gene (rs1800795, rs1800796, rs2069827, rs2069840) and TNF-a (rs361525, rs1799964, rs1800629) promoter region were genotyped. SNP genotyping was performed using Mass Spectrometry (MassARRAY iPLEX–Sequenom). Results: We observed a lower frequency in the minor allele (C) of the TNFa rs1799964 SNP in psoriatic patients, compared with controls [(21.9% vs. 29.4%), p = 0.02, OR = 0.675 (0.49–0.94)]. The frequency of the CC genotype in patients was 3.93% while in the healthy control group it was 9.22% [(p = 0.04, OR = 0.403 (0.17–0.98)]. No statistical significant differences were found in the other polymorphisms. Conclusion: Our data suggest that the rs1799964 C allele could be a protective factor for developing severe psoriasis. These results were similar to the findings of Gallo et al (2012) in a Spanish population. The mechanism to explain this association remains elusive, given the lack of evidence of a functional association

    Estrutura de Propriedade e Gestão no Stress Financeiro: Análise Empírica de Sobrevivência

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    Dissertação de Mestrado em Métodos de Apoio à Decisão EmpresarialNeste estudo oferecemos evidências acerca da relação entre a concentração de propriedade e a dualidade e a sobrevivência das pequenas e médias empresas (PME) portuguesas, formulando as hipóteses de investigação com base nos argumentos da Teoria da Agência, nomeadamente quanto aos conflitos que se estabelecem ao nível da propriedade e entre esta e a gestão. Para o efeito, aplicamos o modelo de riscos proporcionais de Cox a uma amostra 18 145 PME portuguesas. De forma a testar a robustez dos resultados adotamos ainda uma variável alternativa de medição do stress financeiro tendo por base o modelo de Altman (1983). Os resultados obtidos corroboram os argumentos da teoria dos custos de agência Principal-Principal, sugerindo que a dispersão de propriedade tem efeitos negativos na sobrevivência das empresas. No que respeita à estrutura de gestão, os resultados corroboram uma das correntes da teoria dos custos de agência Principal-Agente, sugerindo que a dualidade de funções do proprietário tem efeitos positivos na sobrevivência das empresas.In this study we offer evidence on the relationship between ownership concentration and duality with the survival of Portuguese small and medium-sized enterprises (SME), formulating the research hypotheses based on the arguments of the Agency Theory, namely regarding the conflicts that arise at property level and between property and management. To this end, we apply the Cox proportional hazards model to a sample of 18 145 Portuguese SMEs. In order to test the robustness of the results we also adopted an alternative variable for measuring financial stress based on the Altman (1983) model. The results corroborate the arguments of Principal-Principal agency cost theory, suggesting that ownership dispersion has negative effect on firm survival. Regarding the management structure, the results corroborate one mainstream of Principal-Agent agency cost theory, suggesting that dual owner roles have positive effect on firm survival.N/

    Kaposi sarcoma-An unusual cause of asymptomatic anemia

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