The weakly perturbed Schwarzschild lens in the strong deflection limit

We investigate the strong deflection limit of gravitational lensing by a Schwarzschild black hole embedded in an external gravitational field. The study of this model, analogous to the Chang & Refsdal lens in the weak deflection limit, is important to evaluate the gravitational perturbations on the relativistic images that appear in proximity of supermassive black holes hosted in galactic centers. By a simple dimensional argument, we prove that the tidal effect on the light ray propagation mainly occurs in the weak field region far away from the black hole and that the external perturbation can be treated as a weak field quadrupole term. We provide a description of relativistic critical curves and caustics and discuss the inversion of the lens mapping. Relativistic caustics are shifted and acquire a finite diamond shape. Sources inside the caustics produce four sequences of relativistic images. On the other hand, retro-lensing caustics are only shifted while remaining point-like to the lowest order.Comment: 12 pages, 1 figure

Development of Bursaphelenchus xylophilus-specific microsatellite markers to assess the genetic diversity of populations from European forests.

The pinewood nematode (PWN), Bursaphelenchus xylophilus (Steiner & Buhrer, 1934), Nickle (Nematoda: Aphelenchoididae) is the causal agent of the pine wilt disease and is currently considered as one of the most important pests and pathogens in the world. Its introduction and spread in new forest ecosystems have considerable consequences both economically and environmentally. Therefore, it is of crucial importance to identify its invasion routes, to determine the origin of new outbreaks and to understand the invasion process of this species to prevent further dissemination of the disease in Europe. In order to address these questions using population genetic approaches, we have been developing a set of PWN-specific microsatellite markers, usable in routine conditions at the individual level, thanks to multiplex PCR coupled with a fast DNA extraction method. Microsatellites were isolated from a genomic library using a procedure combining DNA enrichment and high throughput pyrosequencing as recently described by Malausa et al. (2011). Primers were designed for 71 and 23 perfect and compound microsatellites, respectively, 26 of which were experimentally validated so far. Among them, 18 markers exhibited polymorphism after several rounds of amplification tests. Preliminary results on a set of 190 nematodes from 13 populations indicate a very low level of polymorphism in PWN populations from Portugal and Madeira Island, compared to populations from the native area in North America. The genotyping of a wide collection of samples from Europe, Asia and North America is currently underway in the laboratory. Assessing the genetic diversity of populations indeed constitutes the cornerstone to determine whether the European invasive PWN populations are the result of a single or several independent events of introduction

Origin of symbol-using systems: speech, but not sign, without the semantic urge

Natural language—spoken and signed—is a multichannel phenomenon, involving facial and body expression, and voice and visual intonation that is often used in the service of a social urge to communicate meaning. Given that iconicity seems easier and less abstract than making arbitrary connections between sound and meaning, iconicity and gesture have often been invoked in the origin of language alongside the urge to convey meaning. To get a fresh perspective, we critically distinguish the origin of a system capable of evolution from the subsequent evolution that system becomes capable of. Human language arose on a substrate of a system already capable of Darwinian evolution; the genetically supported uniquely human ability to learn a language reflects a key contact point between Darwinian evolution and language. Though implemented in brains generated by DNA symbols coding for protein meaning, the second higher-level symbol-using system of language now operates in a world mostly decoupled from Darwinian evolutionary constraints. Examination of Darwinian evolution of vocal learning in other animals suggests that the initial fixation of a key prerequisite to language into the human genome may actually have required initially side-stepping not only iconicity, but the urge to mean itself. If sign languages came later, they would not have faced this constraint

The frequency-predictability interaction in reading: it depends where you're coming from.

A word's frequency of occurrence and its predictability from a prior context are key factors determining how long the eyes remain on that word in normal reading. Past reaction-time and eye movement research can be distinguished by whether these variables, when combined, produce interactive or additive results, respectively. Our study addressed possible methodological limitations of prior experiments. Initial results showed additive effects of frequency and predictability. However, we additionally examined launch site (the distance from the pretarget fixation to the target) to index the extent of parafoveal target processing. Analyses revealed both additive and interactive effects on target fixations, with the nature of the interaction depending on the quality of the parafoveal preview. Target landing position and pretarget fixation time were also considered. Results were interpreted in terms of models of language processing and eye movement control. Our findings with respect to parafoveal preview and fixation time constraints aim to help parameterize eye movement behavior

Silagens do terço superior de capim-elefante com adição de casca de soja.

bitstream/CPAP/56593/1/CT67.pdfFormato Eletrônico

Diabetic Mastopathy: a Case Report

Diabetic mastopathy (DMP) is an uncommon collection of clinical, radiological, and histological features, classically described in premenopausal women with long-term insulin-dependent diabetes mellitus. This entity can mimic breast carcinoma, but, in the appropriate clinical and imaging setting, the diagnosis can be made by core biopsy, avoiding unnecessary surgeries. We report the case of a 34-year-old female, with a 12-year history of type 1 diabetes, who presented with bilateral breast lumps. Mammography, ultrasonography, and magnetic resonance imaging could not exclude the suspicion of malignancy, and a core biopsy was performed showing the typical histologic features of DMP. The literature is briefly reviewed

Idade, peso e prenhez de novilhas Nelore mocha.

Objetivou-se com este trabalho caracterizar idade, peso e prenhez em novilhas Nelore. Utilizou-se 56 novilhas da raça Nelore, desafiadas com touros para a determinação da idade a primeira prenhez. As novilhas foram pesadas a cada dois meses dos 16 aos 32 meses de idade. Os resultados evidenciaram idade média de 24,10 ± 5,13 meses e peso médio de 304,83 ± 48,23 kg nas 37 novilhas prenhas. Concluiu-se que a idade a primeira prenhez das novilhas Nelore observada neste experimento encontra-se próxima ao descrito na literatura para fêmeas zebuínas, havendo a necessidade de maiores estudos, relacionados ao melhoramento genético e/ou alternativas de manejo, a fim de antecipar a ocorrência da primeira prenhez

Effective refractive index tensor for weak field gravity

Gravitational lensing in a weak but otherwise arbitrary gravitational field can be described in terms of a 3 x 3 tensor, the "effective refractive index". If the sources generating the gravitational field all have small internal fluxes, stresses, and pressures, then this tensor is automatically isotropic and the "effective refractive index" is simply a scalar that can be determined in terms of a classic result involving the Newtonian gravitational potential. In contrast if anisotropic stresses are ever important then the gravitational field acts similarly to an anisotropic crystal. We derive simple formulae for the refractive index tensor, and indicate some situations in which this will be important.Comment: V1: 8 pages, no figures, uses iopart.cls. V2: 13 pages, no figures. Significant additions and clarifications. This version to appear in Classical and Quantum Gravit

Características hematológicas de bovinos (Bos taurus) sadios da raça Pantaneira.

O gado Pantaneiro é a raça brasileira local adaptada às condições extremas de temperatura, umidade e qualidade das pastagens naturais do Pantanal. Com o objetivo de conhecer seus aspectos fisiológicos, foi determinado o perfil hematológico utilizando indivíduos clinicamente sadios. Para isso foram examinadas 293 amostras de sangue colhidas em duas propriedades, no Mato Grosso e Mato Grosso do Sul. Estes animais foram divididos, de acordo com a faixa etária, em cinco grupos: G1, G2, G3, G4 e G5. Estudou-se o eritrograma e o leucograma, submetendo os resultados à estatística descritiva e comparativa para determinação da relação com a idade e sexo.bitstream/item/79836/1/BP104.pd