Ocorrência da antracnose em Stylosanthes spp. no Acre e comportamento de material genético introduzido em relação ao agente causal (colletotrichum gloeosporioides).

Em 1980, uma epifitotia da antracnose do Stylosanthes, causada pelo fungo Collettottrichum gloeosporioides (penz.) Saac., foi observada em pastagens e áreas experimentais do Estado do Acre. Os sintomas característicos da doença são descritos. Inoculação de plântulas de Stylosanthes spp. a partir de culturas puras do fungo proporcionou o aparecimento do mesmos sintomas após 15 dias. Oito gemoplasmas de duas espécies de Stylosanthes spp., S. guayanensis e S. capitata, foram avaliados no campo em duas épocas distintas. S. guayanensis mostrou-se mais suscetível que S. capitata. O isolado do fungo foi também capaz de produzir sintomas em S. humilis. As condições de pastejo prevalentes parecem ter contribuído para aumentar a vulnerabilidade de S. guayanensis cv. Cook à doença

Bent-Double Radio Sources as Probes of Intergalactic Gas

As the most common environment in the universe, groups of galaxies are likely to contain a significant fraction of the missing baryons in the form of intergalactic gas. The density of this gas is an important factor in whether ram pressure stripping and strangulation affect the evolution of galaxies in these systems. We present a method for measuring the density of intergalactic gas using bent-double radio sources that is independent of temperature, making it complementary to current absorption line measurements. We use this method to probe intergalactic gas in two different environments: inside a small group of galaxies as well as outside of a larger group at a 2 Mpc radius and measure total gas densities of $4 \pm 1_{-2}^{+6} \times 10^{-3}$ and $9 \pm 3_{-5}^{+10} \times 10^{-4}$ per cubic centimeter (random and systematic errors) respectively. We use X-ray data to place an upper limit of $2 \times 10^6$ K on the temperature of the intragroup gas in the small group.Comment: 6 pages, 1 figure, accepted for publication in Ap

Localization properties of a tight-binding electronic model on the Apollonian network

An investigation on the properties of electronic states of a tight-binding Hamiltonian on the Apollonian network is presented. This structure, which is defined based on the Apollonian packing problem, has been explored both as a complex network, and as a substrate, on the top of which physical models can defined. The Schrodinger equation of the model, which includes only nearest neighbor interactions, is written in a matrix formulation. In the uniform case, the resulting Hamiltonian is proportional to the adjacency matrix of the Apollonian network. The characterization of the electronic eigenstates is based on the properties of the spectrum, which is characterized by a very large degeneracy. The $2\pi /3$ rotation symmetry of the network and large number of equivalent sites are reflected in all eigenstates, which are classified according to their parity. Extended and localized states are identified by evaluating the participation rate. Results for other two non-uniform models on the Apollonian network are also presented. In one case, interaction is considered to be dependent of the node degree, while in the other one, random on-site energies are considered.Comment: 7pages, 7 figure

Gravitational waves from extreme mass-ratio inspirals in Dynamical Chern-Simons gravity

Dynamical Chern-Simons gravity is an interesting extension of General Relativity, which finds its way in many different contexts, including string theory, cosmological settings and loop quantum gravity. In this theory, the gravitational field is coupled to a scalar field by a parity-violating term, which gives rise to characteristic signatures. Here we investigate how Chern-Simons gravity would affect the quasi-circular inspiralling of a small, stellar-mass object into a large non-rotating supermassive black hole, and the accompanying emission of gravitational and scalar waves. We find the relevant equations describing the perturbation induced by the small object, and we solve them through the use of Green's function techniques. Our results show that for a wide range of coupling parameters, the Chern-Simons coupling gives rise to an increase in total energy flux, which translates into a fewer number of gravitational-wave cycles over a certain bandwidth. For space-based gravitational-wave detectors such as LISA, this effect can be used to constrain the coupling parameter effectively.Comment: RevTex4, 18 pages, 7 figures, 1 tabl

Assessing software development teams' efficiency using process mining

Context. Improving the efficiency and effectiveness of software development projects implies understanding their actual process. Given the same requirements specification, different software development teams may follow different strategies and that may lead to inappropriate use of tools or non-optimized allocation of effort on spurious activities, non-aligned with the desired goals. However, due to its intangibility, the actual process followed by each developer or team is often a black box. Objective. The overall goal of this study is to improve the knowledge on how to measure efficiency in development teams where a great deal of variability may exist due to the humanfactor. The main focus is on the discovery of the underlying processes and compare them in terms of efficiency and effectiveness. By doing so, we expect to reveal potentially hidden costs and risks, so that corrective actions may take place on a timely manner during the software project life cycle. Method. Several independent teams of Java programmers, using the Eclipse IDE, were assigned the same software quality task, related to code smells detection for identifying refactoring opportunities and the quality of the outcomes were assessed by independent experts. The events corresponding to the activity of each team upon the IDE, while performing the given task, were captured. Then, we used process mining techniques to discover development process models, evaluate their quality and compare variants against a reference model used as ”best practice”. Results. Teams whose process model was less complex, had the best outcomes and vice-versa. Comparing less complex process variants with the ”best practice” process, showed that they were also the ones with less differences in the control-flow perspective, based on activities frequencies. We have also determined which teams were most efficient through process analysis. Conclusions. We confirmed that, even for a well-defined software development task, there may be a great deal of process variability due to the human factor. We were able to identify when developers were more or less focused in the essential tasks they were required to perform. Less focused teams had the more complex process models, due to the spurious / non-essential actions that were carried out. In other words, they were less efficient. Experts’ opinion confirmed that those teams also were less effective in their expected delivery. We therefore concluded that a self-awareness of the performed process rendered by our approach, may be used to identify corrective actions that will improve process efficiency (less wasted effort) and may yield to better deliverables, i.e. improved process effectiveness.info:eu-repo/semantics/acceptedVersio

Desempenho produtivo de cultivares de feijão-caupi no Agreste Paraibano.

O objetivo desta pesquisa foi avaliar o comportamento de cultivares de feijão-caupi nas condições do Agreste paraibano. O delineamento experimental foi de blocos casualizados com dez tratamentos (Cultivares: Miranda IPA-207, BRS Marataoã, BRS Guariba, BRS Xique-Xique, BRS Paraguaçu, BRS Cauamé, BRS Tumucumaque, Epace 10, BR 17 Gurguéia e Canapu - local) com quatro repetições. As cultivares apresentaram respostas diferenciadas quanto aos componentes de rendimentos: comprimento de vagem, número de grãos por vagem, peso médio de vagem, massa de 100 grãos e produtividade de grãos. As cultivares de feijão-caupi: BRS Marataoã, BRS Guariba, BRS Xique-Xique, BRS Potengi e Miranda IPA-207 se destacaram com produtividades de grãos acima de 1.000 kg ha-1.CONAC 2012. Disponível em: http://www.conac2012.org/resumos/pdf/139d.pdf. Acesso em: 24 jul. 2013

Efeito de densidades de planta sobre a produtividade de grãos do feijão-caupi.

O objetivo do projeto foi avaliar os efeitos da densidade de plantas sobre o rendimento de grãos e componentes de rendimento da cultivar de feijão-caupi BRS Marataoã. O experimento foi conduzido, sob condições de sequeiro, no período de 01.05.2011 a 23.07.2011 na Estação Experimental de Lagoa Seca - PB . O delineamento experimental foi o de blocos ao acaso com seis tratamentos: densidades: 20, 60,100, 140, 180 e 220 mil plantas ha-1 com cinco repetições. Foram avaliadas o número de vagens por planta, produção de grãos por planta, massa de 100 grãos e produtividade de grãos. Houve efeito linear decrescente do número de vagens por planta e da produção de grãos por planta com o aumento da densidade de plantas e quadrático para massa de 100 grãos e produtividade de grãos. A maior produtividade de grãos (1.233 kg ha-1) foi alcançada com 120 mil plantas ha-1.CONAC 2012. Disponível em: http://www.conac2012.org/resumos/pdf/139c.pdf. Acesso em: 24 jul. 2013

SAF Apícola: sistema agroflorestal integrando abelhas melíferas africanizadas, abelhas nativas sem ferrão, aroeira vermelha e videiras em propriedade familiar de base ecológica.

bitstream/item/30481/1/boletim-84.pd

Cross section, final spin and zoom-whirl behavior in high-energy black hole collisions

We study the collision of two highly boosted equal mass, nonrotating black holes with generic impact parameter. We find such systems to exhibit zoom-whirl behavior when fine tuning the impact parameter. Near the threshold of immediate merger the remnant black hole Kerr parameter can be near maximal (a/M about 0.95) and the radiated energy can be as large as 35% of the center-of-mass energy.Comment: Rearranged results section; accepted for publication in Phys. Rev. Let

Electromagnetic Properties of Kerr-Anti-de Sitter Black Holes

We examine the electromagnetic properties of Kerr-anti-de Sitter (Kerr-AdS) black holes in four and higher spacetime dimensions. Assuming that the black holes may carry a test electric charge we show that the Killing one-form which represents the difference between the timelike generators in the spacetime and in the reference background can be used as a potential one-form for the associated electromagnetic field. In four dimensions the potential one-form and the Kerr-AdS metric with properly re-scaled mass parameter solve the Einstein-Maxwell equations, thereby resulting in the familiar Kerr-Newman-AdS solution. We solve the quartic equation governing the location of the event horizons of the Kerr-Newman-AdS black holes and present closed analytic expressions for the radii of the horizons. We also compute the gyromagnetic ratio for these black holes and show that it corresponds to g=2 just as for ordinary black holes in asymptotically flat spacetime. Next, we compute the gyromagnetic ratio for the Kerr-AdS black holes with a single angular momentum and with a test electric charge in all higher dimensions. The gyromagnetic ratio crucially depends on the dimensionless ratio of the rotation parameter to the curvature radius of the AdS background. At the critical limit, when the boundary Einstein universe is rotating at the speed of light, it tends to g=2 irrespective of the spacetime dimension. Finally, we consider the case of a five dimensional Kerr-AdS black hole with two angular momenta and show that it possesses two distinct gyromagnetic ratios in accordance with its two orthogonal 2-planes of rotation. In the special case of two equal angular momenta, the two gyromagnetic ratios merge into one leading to g=4 at the maximum angular velocities of rotation.Comment: Typos corrected; 31 pages, REVTe