5,772 research outputs found

    Caracterização do óleo de pinhão-manso (Jatropha curcas L.).

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    O pinhão manso (Jatropha curcas L.), pertencente a familia Euphorbiaceae, e uma planta nativa da America tropical, naturalizada em partes tropicais e subtropicais da Africa e Asia. Sua distribuição geografica e bastante vasta devido a sua rusticidade, resistencia a longas estiagens, bem como a pragas e doencas, sendo adaptavel a condicoes edafoclimaticas muito variaveis. O fruto de J.curcas contem oleo viscoso que pode ser usado na industria de cosmeticos, como substituto do querosene, e na fabricacao de sabao e combustivel para motores diesel. Este trabalho tem como objetivo caracterizar o oleo de pinhao manso segundo sua composicao quimica e parâmetros fisico-quimicos, tendo em vista sua utilizacao para a producao de biocombustivel..

    Theory and modeling of the magnetic field measurement in LISA PathFinder

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    The magnetic diagnostics subsystem of the LISA Technology Package (LTP) on board the LISA PathFinder (LPF) spacecraft includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at their respective positions. However, their readouts do not provide a direct measurement of the magnetic field at the positions of the test masses, and hence an interpolation method must be designed and implemented to obtain the values of the magnetic field at these positions. However, such interpolation process faces serious difficulties. Indeed, the size of the interpolation region is excessive for a linear interpolation to be reliable while, on the other hand, the number of magnetometer channels does not provide sufficient data to go beyond the linear approximation. We describe an alternative method to address this issue, by means of neural network algorithms. The key point in this approach is the ability of neural networks to learn from suitable training data representing the behavior of the magnetic field. Despite the relatively large distance between the test masses and the magnetometers, and the insufficient number of data channels, we find that our artificial neural network algorithm is able to reduce the estimation errors of the field and gradient down to levels below 10%, a quite satisfactory result. Learning efficiency can be best improved by making use of data obtained in on-ground measurements prior to mission launch in all relevant satellite locations and in real operation conditions. Reliable information on that appears to be essential for a meaningful assessment of magnetic noise in the LTP.Comment: 10 pages, 8 figures, 2 tables, submitted to Physical Review

    Endotracheal Intubation – A Dilemma in Pre-hospital Care.

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    A intubação endotraqueal (IET), no pré-hospitalar, é considerada o “gold standard” na manutenção da via aérea de modo a fornecer a ventilação e oxigenação à pessoa em situação crítica, no entanto, está associada a várias complicações e riscos. Com este trabalho de revisão sistemática da literatura pretendeu-se compreender a relação entre a IET em emergência pré-hospitalar e o prognóstico da pessoa em situação crítica, colocando a seguinte questão: “Qual o impacto da intubação endotraqueal, em emergência pré-hospitalar, no prognóstico clínico do doente?”. Este trabalho de investigação iniciou-se com uma pesquisa da literatura de língua inglesa e portuguesa, nas bases de dados científicas MEDLINE, CINAHL, MedicLatina e Nursing and Allied Health Collection num horizonte temporal entre 2010 e 2014. A evidência destaca que a realização da intubação endotraqueal, no pré-hospitalar, está associada a piores taxas de reanimação cardiorrespiratória, ao aumento das taxas de mortalidade e ao aumento das comorbilidades. Estas conclusões reforçam a discussão em torno da prática da IET no pré-hospitalar e sensibilizam os profissionais de saúde para a limitação desta prática a casos em que exista indicação clínica segura

    Anomalous Hall effect in superconductors with spin-orbit interaction

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    We calculate the anomalous Hall conductance of superconductors with spin-orbit interaction and with either uniform or local magnetization. In the first case we consider a uniform ferromagnetic ordering in a spin triplet superconductor, while in the second case we consider a conventional s-wave spin singlet superconductor with a magnetic impurity (or a diluted set of magnetic impurities). In the latter case we show that the anomalous Hall conductance can be used to track the quantum phase transition, that occurs when the spin coupling between the impurity and electronic spin density exceeds a certain critical value. In both cases we find that for large spin-orbit coupling the superconductivity is destroyed and the Hall conductance oscillates strongly.Comment: 10 pages, 6 figure

    Two Kerr black holes with axisymmetric spins: An improved Newtonian model for the head-on collision and gravitational radiation

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    We present a semi-analytical approach to the interaction of two (originally) Kerr black holes through a head-on collision process. An expression for the rate of emission of gravitational radiation is derived from an exact solution to the Einstein's field equations. The total amount of gravitational radiation emitted in the process is calculated and compared to current numerical investigations. We find that the spin-spin interaction increases the emission of gravitational wave energy up to 0.2% of the total rest mass. We discuss also the possibility of spin-exchange between the holes.Comment: 8 pages, RevTeX, 2 figures, psbox macro include

    Local boron doping quantification in homoepitaxial diamond structures

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    The capability of transmission electronmicroscopy (TEM) using the high angle annular dark fieldmode (HAADF,also labelled Z-contrast) to quantify boron concentration, in the high doping range between 1019cm−3 and 1021cm−3, is demonstrated. Thanks to the large relative variation of atomic number Z between carbon and boron, doping concentration maps and profiles are obtained with a nanometer-scale resolution. A novel numerical simulation procedure allows the boron concentration quantification and demonstrates the high sensitivity and spatial resolution of the technique.4 page

    The Effect of Adverse Oil Price Shocks on Monetary Policy and Output Using a Dynamic Small Open Economy General Equilibrium Model With Staggered Price for Brazil

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    The aim of the present research is to use a model economy built for Brazil, based on an optimizing dynamic general equilibrium model, in order to perform numerical simulations to derive the ability of the artificial economy to explain the impact of monetary policy interventions on Brazilian short run economic performance in terms of the inflation rate, output gap, interest rate and level of economic activity in the face of an adverse oil shock. It is an extension of Bugarin et al. (2005) concentrating on the consequence of energy price increases, facing different monetary policy rules. Following Hall (1988 e 1990) and Finn (2000) it is considered that an increase in energy prices acts like a negative productivity shock. The model provides an accessible description of an artificial economy with a tractable micro-founded dynamic setting with forward looking rational agents in a small open economy with a staggered pricing mechanism that generates inflation inertia and recessionary disinflations. Alternative specification of monetary reaction functions are introduced into the model economy in order to perform a sensitivity analysis of derived impulse responses to those interventions facing the negative productivity shock. The preliminary results suggest that the introduction of habit persistence into the consumption hypothesis does not make much difference. However the introduction of different monetary reaction functions does alter the impulse response of output, inflation rate, and nominal interest rate. A common result is the decline in potential output for all models. Additionally, the only case where a reduction in the output gap is observed is when using the Taylor rule that takes into consideration the output gap and past interest rates with high persistence.

    The Highly Miniaturised Radiation Monitor

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    We present the design and preliminary calibration results of a novel highly miniaturised particle radiation monitor (HMRM) for spacecraft use. The HMRM device comprises a telescopic configuration of active pixel sensors enclosed in a titanium shield, with an estimated total mass of 52 g and volume of 15 cm3^3. The monitor is intended to provide real-time dosimetry and identification of energetic charged particles in fluxes of up to 108^8 cm2^{-2} s1^{-1} (omnidirectional). Achieving this capability with such a small instrument could open new prospects for radiation detection in space.Comment: 17 pages, 15 figure

    Avaliação de parâmetros monocíclicos e da densidade da ferrugem asiática (Phakopsora pachyrhizi) em diferentes genótipos de soja e posições de copa.

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    RESUMO: A ferrugem da soja destacou-se nas últimas safras devido à alta severidade que vem causando nas lavouras de soja. Diversos estudos estão em andamento, para buscar informações sobre a resistência genética dos cultivares atualmente plantados. O objetivo do trabalho foi estudar parâmetros monocíclicos e o progresso da ferrugem da soja em diferentes genótipos e posições da copa, em casa-de-vegetação. Foram utilizados 7 cultivares (Uirapuru e BRS 134 Pintado, BRS 134, BRS 154, BRS 215, FT 2, BRS 231) e uma PI 459025 com gene de resistência Rpp4, inoculados com suspensão de esporos de Phakopsora pachyrhizi. Foram estudados para cada genótipos os períodos de incubação e latente. A avaliação de incidência da ferrugem foi realizada na planta toda e da severidade a partir do aparecimento dos sintomas, a cada cinco dias, até o declínio das plantas em três posições na copa. Os valores foram transformados em área abaixo da curva de progresso da incidência (AACPI) e da severidade (AACPS) da doença. O período de incubação foi de seis dias para todos genótipos avaliados. Entretanto, o período latente variou de 6 a 12 dias. Houve diferença significativa entre os cultivares para AACPI. Os cultivares BRS 134, FT 2 e BRS 231 apresentaram maior valor de AACPI, diferenciando dos demais cultivares. Entre os cultivares com menor valor de AACPI destacou-se a PI 459025. Variação na intensidade da doença nos 8 genótipos avaliados, em relação à posição da copa, só pode ser observada para o terço média da planta. ABSTRACT: Soybean rust caused by the fungus Phakopsora pachyrhizi, has been known to drastically reduce yields. Diverse studies are now in progress, to search information on the genetic resistance of cultivar currently planted. The objective of this study was to evaluate the both incubation and latent period and the progress of soybean rust on several genotypes and three canopy position in greenhouse. The cultivars used were Uirapuru, BRS 134 Pintado, BRS 154, BRS 215, BRS 231, FT 2 and PI 459025 with a Ppp4 gene of resistance for soybean rust. Inoculations were performed by spraying inoculum suspension on the leaves. Disease incidence and severity were assessed every five days after the first disease symptoms were observed until plants were dead. The incubation period was six days for all genotypes evaluated. However, the latent period varied from six to twelve days. The incidence and severity values were transformed in proportion as the area under the disease incidence curve (AUDIC) and area under the disease severity curve (AUDSC). The cultivars BRS 134 Pintado, FT 2 and BRS 231 showed high values for AUDIC and were significant different from the others. PI 459025 showed the lowest value for AUDIC. AUDSC for PI 459025 cultivar was the lowest and FT 2 showed the highest value. Difference from disease intensity on eight genotypes, in function of the canopy position, only was observe to plant medium part
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