Avaliação econômica de pastagens: método da taxa interna de retorno com uso de microcomputador.

As baixas qualidade e disponibilidade das pastagens, especialmente na estação seca, têm sido apontadas como as principais causas do baixo desfrute do rebanho brasileiro. Na tentativa de encontrar soluções para este problema, pesquisadores, extensionistas e produtores têm intensificado esforços na busca de gramíneas exóticas, bem como estratégias alternativas para formação e conservação de pastagem cultivada, para oferecer melhor alimentação para os rebanhos a custos mais baixos. Entretanto, um aspecto que deve ser levado em conta na busca da pastagem mais adequada é a multiplicidade de condições em cada fazenda. Diferentes categorias animais e condições de clima, solo, vegetação nativa e infraestrutura regional, determinam as espécies forrageiras e os sistemas de formação e conservação de pastagem mais adequados economicamente. Dentre os métodos de formação e conservação de pastagens, há um grande número de alternativas. O método de abertura da mata, mecânico ou manual, o aproveitamento Inicial da área, com lavoura ou capim. a intensidade de uso e conservação da pastagem. a freqüência de rocadas e adubação constituem decisões determinantes de custos e benefício das pastagens.bitstream/item/131376/1/avaliacao-economica-de-pastagens.pd

A polynomial eigenvalue approach for multiplex networks

We explore the block nature of the matrix representation of multiplex networks, introducing a new formalism to deal with its spectral properties as a function of the inter-layer coupling parameter. This approach allows us to derive interesting results based on an interpretation of the traditional eigenvalue problem. Specifically, our formalism is based on the reduction of the dimensionality of a matrix of interest but increasing the power of the characteristic polynomial, i.e, a polynomial eigenvalue problem. This approach may sound counterintuitive at first, but it enable us to relate the quadratic eigenvalue problem for a 2-Layer multiplex network with the spectra of its respective aggregated network. Additionally, it also allows us to derive bounds for the spectra, among many other interesting analytical insights. Furthermore, it also permits us to directly obtain analytical and numerical insights on the eigenvalue behavior as a function of the coupling between layers. Our study includes the supra-adjacency, supra-Laplacian and the probability transition matrices, which enables us to put our results under the perspective of structural phases in multiplex networks. We believe that this formalism and the results reported will make it possible to derive new results for multiplex networks in the future

Role of coat colour in body heat regulation among goats and hairy sheep in tropics.

Abstract: This experirnent was conducted during the hottest and the leanest period of the year in the tropical semi-arid northeast of Brazil to evaluate the relative response of black and white va- rieties (with the colour of skin and of haïr being the same) of goats and hairy sheep to grazing under direct solar radiation. There was a marked increase in midside-skin (MS), oar-skin (ES) and rectal temperatures (R T) and respiratory rate (RR) at 2 P .M. The afternoon increase was more in sheep in MS, RT and RR, but ES increased more in goats. Black animais had uniformly higher MS. White sheep had higher ES but in goats colour had no effect. Right ES was higher in sheep and there was some tendency of higher right ES in general. The black goats respired at much higher rates than the white, but in sheep, colour did not influence RR. Colour of animais did not influence RT. There was signi- ticant day-to-day variation, possibly associated with small fluctuations in environmental temperature, in MS, ES and RR but not in RT. The results indicate that goats appear to be better adapted than hairy sheep and white goats better than black goats under local climatic conditions. [Influência da cor da pelagem na regulação do calor em caprinos e ovinos sem-lã no trópico]. Resumo: Este experimento foi conduzido na região tropical do nordeste Brasileiro para avaliar a resposta relativa ao calor dos caprinos e ovinos sem-lã de pelagem (pele + pêlo) branca e preta em pastejo e expostos diretamente à radiação solar. Houve um aumento marcante nas temperaturas da pele da costela (PC), pele da orelha (PO) e retal (TR) e no rítmo respiratório (RR) às 14h. À tarde, a elevação foi maior em ovinos na PC, TR e no RR, mas PO aumentou mais nos caprinos. Animais pretos tinham, uniformemente, maior PC. Os ovinos brancos exibiram maior PO, mas no caprinos a cor não influenciou. ES direita foi superior em ovinos e houve tendência da PO direita ser, em geral, superior. Caprinos de cor preta apresentaram maior elevação no RR do que os de cor branca, mas nos ovinos a cor não influenciou o RR. Cor da pelagem não teve influência na TR. Houve uma variação diária significante na PC, PO e RR, mas não na TR, possivelmente associado com flutuações na temperatura ambiental. Resultados indicam que caprinos parecem ser melhor adaptados do que ovinos sem-lã e caprinos brancos melhor que caprinos pretos sob as condições climáticas locais

Disease localization in multilayer networks

We present a continuous formulation of epidemic spreading on multilayer networks using a tensorial representation, extending the models of monoplex networks to this context. We derive analytical expressions for the epidemic threshold of the susceptible-infected-susceptible (SIS) and susceptibleinfected- recovered dynamics, as well as upper and lower bounds for the disease prevalence in the steady state for the SIS scenario. Using the quasistationary state method, we numerically show the existence of disease localization and the emergence of two or more susceptibility peaks, which are characterized analytically and numerically through the inverse participation ratio. At variance with what is observed in single-layer networks, we show that disease localization takes place on the layers and not on the nodes of a given layer. Furthermore, when mapping the critical dynamics to an eigenvalue problem, we observe a characteristic transition in the eigenvalue spectra of the supra-contact tensor as a function of the ratio of two spreading rates: If the rate at which the disease spreads within a layer is comparable to the spreading rate across layers, the individual spectra of each layer merge with the coupling between layers. Finally, we report on an interesting phenomenon, the barrier effect; i.e., for a three-layer configuration, when the layer with the lowest eigenvalue is located at the center of the line, it can effectively act as a barrier to the disease. The formalism introduced here provides a unifying mathematical approach to disease contagion in multiplex systems, opening new possibilities for the study of spreading processes

A general Markov chain approach for disease and rumour spreading in complex networks

Spreading processes are ubiquitous in natural and artificial systems. They can be studied via a plethora of models, depending on the specific details of the phenomena under study. Disease contagion and rumour spreading are among the most important of these processes due to their practical relevance. However, despite the similarities between them, current models address both spreading dynamics separately. In this article, we propose a general spreading model that is based on discrete time Markov chains. The model includes all the transitions that are plausible for both a disease contagion process and rumour propagation. We show that our model not only covers the traditional spreading schemes but that it also contains some features relevant in social dynamics, such as apathy, forgetting, and lost/recovering of interest. The model is evaluated analytically to obtain the spreading thresholds and the early time dynamical behaviour for the contact and reactive processes in several scenarios. Comparison with Monte Carlo simulations shows that the Markov chain formalism is highly accurate while it excels in computational efficiency. We round off our work by showing how the proposed framework can be applied to the study of spreading processes occurring on social networks

Estimativa do custo de producao da carne bovina para a regiao Centro-oeste: setembro de 1986.

bitstream/item/138579/1/COT-30.pdfCNPGC

Diagnóstico e tratamento da mastite.

bitstream/item/60508/1/IT110001.pd

Teste alternativo para avaliação do potencial fisiológico de sementes de milho e feijão de porco.

bitstream/item/56906/1/COT89-lancado.pd

PANVASCULITE SEPTICÊMICA EM BOVINO JOVEM: ACHADOS IMAGIOLÓGICOS, CLÍNICO-PATOLÓGICOS E MICROBIOLÓGICOS – RELATO DE CASO Amabile

Umbilical disorders affect young calves varying from 28% to 42.2% in Brazilian livestock properties. This paper describes the imagiological, clinicopathological, and microbiological aspects presented by a calf affected by septicemic panvasculitis. A 2-month-old calf conceived by natural means was attended at the Veterinary Hospital (HV) of the Federal University of Paraiba (UFPB), presenting pelvic limb joints swelling. Physical examination revealed tarsus and stifle joint swelling with presence of a fistulated wound. Bimanual palpation of abdomen revealed umbilical region swelling, with purulent discharge, pain sensitivity and thickening of veins and umbilical arteries. The patient was hospitalized and a conservative treatment was preconized. Complementary examinations were made. Ultrasonographic examination of the abdominal cavity revealed alterations in the umbilical vein: hyperechoic lumen and a thickened, hypoechoic with hyperechoic sites in vessel wall. Liver showed multifocal hyperechoic structures. Hemogram showed no significant alterations and the microbiological culture did not grow. Due to sonographic alterations in the liver and umbilical vein, in addition to the presence of polyarthritis, euthanasia was chosen after 11 days of treatment. Necropsy showed thickening and presence of exudate in allantoic duct and umbilical vein; bladder with granulomatous exudate; abscesses in liver, pleura, bone marrow, omentum, spleen and joints. Histopathological findings revealed mixed infiltrates in mesenteric lymph nodes, spleen, pleura, intestine, esophagus, liver, bladder, kidneys, bone and nervous system. Microbiological isolation identified P. mirabilis as the cause of the infection, which showed multiple resistance to ampicillin, amoxicillin clavulanate, gentamicin, sulfazotrim, cephalothin, and tetracycline in the In vitro bacterial susceptibility test. It was concluded that ultrasonographic examination was indispensable to reach the prognosis of the clinical case, besides showing more information related to the involvement of the umbilical vessels, allowing visualization and measurement of lumen and vascular wall.Afecções umbilicais são responsáveis por acometer bezerros jovens tendo prevalência de 28% a 42,2% nas propriedades de gado do Brasil. Assim, objetiva-se descrever os aspectos clínico-patológicos, imagiológicos e microbiológicos em um bezerro acometido por panvasculite septicêmica. Um bezerro com 2 meses de idade, concebido por meio natural, foi atendido no Hospital Veterinário (HV) da Universidade Federal da Paraíba (UFPB), apresentando aumento das articulações dos membros pélvicos. No exame físico foi visto aumento de volume em articulações e ferida fistulada. O exame bimanual do abdômen mostrou presença de secreção purulenta, sensibilidade e espessamento de veias e artérias umbilicais. Tratamento conservativo foi preconizado e exames complementares foram feitos. Exame ultrassonográfico revelou veia umbilical com parede espessada, hipoecóica com pontos hiperecóicos, lúmen hiperecóico e áreas hiperecóicas multifocais em fígado. O hemograma não mostrou alterações significativas e a cultura microbiológica não cresceu. Devido às alterações ultrassonográficos vitas em fígado e veia umbilical, além da poliartrite, optou-se pela eutanásia 11 dias após início de tratamento. Na necropsia foi visto espessamento e presença de exsudato em ducto alantóide e veia umbilical; bexiga com exsudato granulomatoso; abscessos em fígado, pleura, medula óssea, omento, baço e articulações. Achados histopatológicos revelaram infiltrados mistos em linfonodos mesentéricos, baço, pleura, intestino, esôfago, fígado, bexiga, rins, osso e sistema nervoso. O isolamento microbiológico identificou P. mirabilis como causador da infecção, o qual mostrou múltipla resistência a ampicilina, amoxicilina clavulanato, gentamicina, sulfazotrim, cefalotina, e tetraciclina. Conclui-se que o exame ultrassonográfico foi indispensável para se chegar ao prognóstico do caso clínico, além de mostrar mais informações relacionadas ao acometimento dos vasos umbilicais, permitindo visualização e mensuração de lúmen e parede vascular