1,175 research outputs found

    IPR AFRODITE - new oat cultivar with nematode resistance

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    Transmission fiber chromatic dispersion dependence on temperature: implications on 40 Gb/s performance

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    In this letter we will evaluate the performance degradation of a 40 km high-speed (40 Gb/s) optical System, induced by optical fiber variations of the chromatic dispersion induced by temperature changes. The chromatic dispersion temperature sensitivity will be estimated based on the signal quality parameters

    Análises fitoquímicas em extrato das folhas de Anthurium affine Schott (milho de urubu)

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    Apesar da ampla disposição de medicamentos no mercado, muitas dificuldades ainda existem quanto ao tratamento de determinados tipos de doenças, como é o caso das dermatites nos animais domésticos, mais especificamente nos cães. Apoiando-se na hipótese de que plantas da família das Araceae podem oferecer insumos importantes no tratamento deste tipo de doença, idealizou-se este trabalho tendo-se como principal objetivo estudar mais precisamente a composição fitoquímica do Anthurium affine Schott (A. affine), conhecido popularmente como “milho de urubu”. A partir de amostras da planta colhidas na Região Metropolitana do Grande Recife, foi confeccionado o extrato hidroalcóolico (etanol a 70%), das folhas da planta, sendo colocado para maceração por sete dias. A partir desta etapa o material foi submetido a procedimentos de filtragem e caracterização do extrato final obtido. Posteriormente, alíquotas deste material foram colhidas e trabalhadas para a realização dos ensaios de identificação fitoquímica, conforme protocolo padrão disponível na literatura. Como resultados, obteve-se um extrato hidroalcóolico da planta na concentração de 85 mg/mL; as análises fitoquímicas apresentaram resposta positiva para taninos, flavonóides, alcalóides e saponinas. Verificou-se que o A. affine apresentou um potencial fitoterápico mais rico do que normalmente se apresenta, embora estudos mais precisos sejam necessários para se avaliar os reais riscos de toxicidade no uso terapêutico da planta, como também para melhor definir os mecanismos de ação por traz dos efeitos farmacológicos atribuídos aos seus extratos

    Structural phase transition in IrTe2_2: A combined study of optical spectroscopy and band structure calculations

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    Ir1x_{1-x}Ptx_xTe2_2 is an interesting system showing competing phenomenon between structural instability and superconductivity. Due to the large atomic numbers of Ir and Te, the spin-orbital coupling is expected to be strong in the system which may lead to nonconventional superconductivity. We grew single crystal samples of this system and investigated their electronic properties. In particular, we performed optical spectroscopic measurements, in combination with density function calculations, on the undoped compound IrTe2_2 in an effort to elucidate the origin of the structural phase transition at 280 K. The measurement revealed a dramatic reconstruction of band structure and a significant reduction of conducting carriers below the phase transition. We elaborate that the transition is not driven by the density wave type instability but caused by the crystal field effect which further splits/separates the energy levels of Te (px_x, py_y) and Te pz_z bands.Comment: 16 pages, 5 figure

    Improving the Creation of Hot Spot Policing Patrol Routes: Comparing Cognitive Heuristic Performance to an Automated Spatial Computation Approach

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    Hot spot policing involves the deployment of police patrols to places where high levels of crime have previously concentrated. The creation of patrol routes in these hot spots is mainly a manual process that involves using the results from an analysis of spatial patterns of crime to identify the areas and draw the routes that police officers are required to patrol. In this article we introduce a computational approach for automating the creation of hot spot policing patrol routes. The computational techniques we introduce created patrol routes that covered areas of higher levels of crime than an equivalent manual approach for creating hot spot policing patrol routes, and were more efficient in how they covered crime hot spots. Although the evidence on hot spot policing interventions shows they are effective in decreasing crime, the findings from the current research suggest that the impact of these interventions can potentially be greater when using the computational approaches that we introduce for creating hot spot policing patrol routes

    Thermoelectric spin voltage in graphene

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    In recent years, new spin-dependent thermal effects have been discovered in ferromagnets, stimulating a growing interest in spin caloritronics, a field that exploits the interaction between spin and heat currents. Amongst the most intriguing phenomena is the spin Seebeck effect, in which a thermal gradient gives rise to spin currents that are detected through the inverse spin Hall effect. Non-magnetic materials such as graphene are also relevant for spin caloritronics, thanks to efficient spin transport, energy-dependent carrier mobility and unique density of states. Here, we propose and demonstrate that a carrier thermal gradient in a graphene lateral spin valve can lead to a large increase of the spin voltage near to the graphene charge neutrality point. Such an increase results from a thermoelectric spin voltage, which is analogous to the voltage in a thermocouple and that can be enhanced by the presence of hot carriers generated by an applied current. These results could prove crucial to drive graphene spintronic devices and, in particular, to sustain pure spin signals with thermal gradients and to tune the remote spin accumulation by varying the spin-injection bias

    Satisfaction with Life Scale among adolescents and young adults in Portugal: extending evidence of construct validity

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    The paper presents three empirical studies designed to extend the test of the construct validity of the Satisfaction With Life Scale (SWLS) among Portuguese students. In the first study, the responses of 461 elementary and secondary education students were submitted to a principal component analysis. A solution of one single factor was chosen, accounting for 55.7 % of the total variance, with Cronbach alpha coefficient and inter-item correlation above .70 and .20, respectively. The second study used a sample of 317 undergraduate students and registered a similar factor solution for SWLS (/pq = 0.99), which accounted for 65.6 % of the total variance (Cronbach alpha .89 and inter-item correlation above .20). A test–retest analysis registered coefficients of .70 (T2) and .77 (T3) and no significant statistically differences between T2, T3 and T1. The third study used a sample of 107 foster care youths from elementary and secondary education. Confirmatory factor analysis results indicate adequate fit indexes for the one-factor solution (v2/df = 2.70, GFI = .96, CFI = .96), which showed convergent validity, reliability and homogeneity. In conclusion, there is psychometric evidence for the one-factor structure of the SWLS in Portugal.FCTCOMPET

    A molecular method for the detection of sally lightfoot crab larvae (Grapsus grapsus, Brachyura, Grapsidae) in plankton samples

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    The decapod Grapsus grapsus is commonly found on oceanic islands of the Pacific and Atlantic coasts of the Americas. In this study, a simple, quick and reliable method for detecting its larvae in plankton samples is described, which makes it ideal for large-scale studies of larval dispersal patterns in the species

    Neutron Stars in Teleparallel Gravity

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    In this paper we deal with neutron stars, which are described by a perfect fluid model, in the context of the teleparallel equivalent of general relativity. We use numerical simulations to find the relationship between the angular momentum of the field and the angular momentum of the source. Such a relation was established for each stable star reached by the numerical simulation once the code is fed with an equation of state, the central energy density and the ratio between polar and equatorial radii. We also find a regime where linear relation between gravitational angular momentum and moment of inertia (as well as angular velocity of the fluid) is valid. We give the spatial distribution of the gravitational energy and show that it has a linear dependence with the squared angular velocity of the source.Comment: 19 pages, 14 figures. arXiv admin note: text overlap with arXiv:1206.331
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