Gastric ulcers in pigs affected with postweaning multisystemic wasting syndrome

Samples of gastric lymph nodes and the stomachs from 24 pigs selected from herds affected by postweaning multisystemic wasting syndrome (PMWS) and sudden death associated with gastric ulcers were studied. Pigs were selected on the basis of unthriftiness, decreased feed intake, and wasting. The stomachs were opened, inverted, and classified into 0-3 score according the severity of the gross lesions present in pars oesophagica (non-glandulargastric mucosa). Selected samples were processed for paraffin embedding and stained with hematoxylin and eosin. Immunohistochemistry using anti-PCV2 (porcine circovírus type 2) antibody, anti-Helicobacter pylori antibody and a wide-spectrum anti-cytokeratin antibody was performed. Gross changes in pars oesophagea were classified according to the severity of lesions as score 3, 2, and 1 in 8, 6, 5 stomachs respectivelly. Microscopically, hyperplastic lymphoid follicles, lymphohistiocytic inflammatory infiltrates and focci of necrosis in the gastric mucosa were common findings. Large amounts of PCV2 antigen were observed in the cytoplasm and nuclei from intralesional cells and debris from the gastric glandular mucosal zone; however, in the fundus, anti-PCV2 immunostaining was restricted to the surface mucosal cells and foveolar compartment. All gastric lymph nodes were positive for PCV2 antigen. Anti-H. pylori immunostaining was seen in eleven cases, mainly in the antrum, on the mucosal surface and foveolar compartment. The association of the anti-PCV2 immunostaining with the glandular mucus-producing cells suggests a role for PCV2 as an additional factor for the swine ulcer development.

Análise filogenética de isolados do vírus da raiva de herbívoros na fronteira de Minas Gerais e São Paulo (2000-2009), Brasil

A raiva transmitida por morcegos hematófagos da espécie Desmodus rotundus representa uma preocupação de saúde pública e causa de importantes prejuízos para a pecuária brasileira. A evidência atual sugere que a ocorrência de raiva está relacionada às características da paisagem, topografia, hidrografia, sistemas de produção animal e usos da terra. Contudo, existem poucos estudos que analisem as possíveis conexões entre fatores geográficos e a diversidade molecular do vírus da raiva, permitindo a compreensão da dinâmica espacial e temporal dos focos de raiva. Um desses trabalhos estabeleceu que a última epizootia de raiva dos herbívoros registrada no leste do estado de São Paulo (na fronteira com Minas Gerais), aconteceu em duas ondas epidêmicas, sendo a primeira em 1998 e, em 1999, a segunda. Considerando esta evidência, o intuito do presente estudo foi analisar casos de raiva em herbívoros na região sudeste de Minas Gerais (2000-2009) e sua possível relação com a epidemia previamente mencionada, incluindo as características geográficas da região. Foram obtidas sequencias parciais dos genes da glicoproteína (539 nt) e da nucleoproteína (414 nt) a partir de 31 isolados de vírus da raiva procedentes de herbívoros. Foi proposta uma árvore filogenética para cada região genômica usando o método de Neighbor joining, fixando o modelo evolutivo Kimura 2 - parâmetros com um nível de bootstrap de 1000 replicações. As sublinhagens genéticas foram localizadas sobre mapas, considerando as áreas de risco para raiva dos herbívoros em São Paulo, assim como as características topográficas e bacias hidrográficas com o intuito de visualizar qualquer padrão aparente de distribuição segundo essas características. As duas árvores filogenéticas mostraram topologias concordantes, sugerindo uma possível origem comum para os surtos que aconteceram ao longo da fronteira SP/MG, ao redor das porções menos elevadas da Serra da Mantiqueira e acompanhando as bacias hidrográficas dos rios Piracicaba/Jaguarí, Paranaíba do Sul, Grande, Pardo e Mogi-Guaçu. Foi possível observar circulação de varias linhagens virais simultaneamente em alguns municípios, possivelmente por causa de sobreposição de surtos. As sequencias de proteína inferidas a partir dos dois genes mostraram mutações sinônimas, excetuando aquelas encontradas entre os resíduos 20 a 200, correspondentes ao domínio externo da glicoproteína. Esta informação salienta a importância da cooperação entre as autoridades sanitárias de ambos os estados para reforçar o programa de controle da doença nas áreas limítrofes.

Non-Linear Unsteady Aerodynamic Response Approximation Using Multi-Layer Functionals

Non-linear functional representation of the aerodynamic response provides a convenient mathematical model for motion-induced unsteady transonic aerodynamic loads response, that accounts for both complex non-linearities and time-history effects. A recent development, based on functional approximation theory, has established a novel functional form; namely, the multi-layer functional. For a large class of non-linear dynamic systems, such multi-layer functional representations can be realised via finite impulse response (FIR) neural networks. Identification of an appropriate FIR neural network model is facilitated by means of a supervised training process in which a limited sample of system input-output data sets is presented to the temporal neural network. The present work describes a procedure for the systematic identification of parameterised neural network models of motion-induced unsteady transonic aerodynamic loads response. The training process is based on a conventional genetic algorithm to optimise the network architecture, combined with a simplified random search algorithm to update weight and bias values. Application of the scheme to representative transonic aerodynamic loads response data for a bidimensional airfoil executing finite-amplitude motion in transonic flow is used to demonstrate the feasibility of the approach. The approach is shown to furnish a satisfactory generalisation property to different motion histories over a range of Mach numbers in the transonic regime.

Initialism as a mechanism of weed interference: can a crop plant be blinded?

Initialism is a new word proposed to indicate the "shade-avoidance syndrome". Plants detect the presence of neighbor plants very early in the growing season through changes in light quality. They modify the allocation of photosynthesis products privileging shoot growth over the roots. One of the hypotheses of the authors is that, when weed management is timely scheduled, a "blind" crop could be more productive because it would avoid an imbalance on the shoot:root ratio (S:R). Two strategies were developed to test this hypothesis: a) to use the classical Yoda's Law to screen several crops for insensitivity to S:R imbalance; b) to evaluate several growth regulators to control the plant responses to crowding. Experimental results confirm that both strategies can yield insensitive plants. The possibilities of the use of this knowledge are discussed.

Weed suppression in the formation of brachiarias under three sowing methods

The success of conservation systems such as no-till depends on adequate soil cover throughout the year, which is possible through the use of cover crops. For this purpose the species belonging to the genus Urochloa has stood out by virtue of its hardiness and tolerance to drought. Aiming ground cover for the no-till system, the objective was to evaluate the establishment of two species of the genus Urochloa, in three sowing methods, in the weed suppression and the sensitivity of these forages to glyphosate. The study design was a randomized block with a 2 x 3 x 3 factorial arrangement, in which factor A was composed of Urochloa ruziziensis and Urochloa hybrid CIAT 36087 cv. Mulato II, factor B was formed by sowing methods: sown without embedding, sown with light embedding and sown in rows, and factor C was composed of three doses of glyphosate (0.975, 1.625 and 2.275 kg ha-1 of acid equivalent). For determination of weed suppression, assessment of biomass yield and soil cover was performed, by brachiaria and weeds, at 30, 60, 90, 120 and 258 days after sowing. Visual assessment of the desiccation efficiency at 7 and 14 days after herbicide application was performed. It is concluded that embedding Urochloa seeds stands out in relation to sowing in the soil surface. Urochloa ruziziensis is more efficient in the dry weight yield, weed suppression, in addition to being more sensitive to glyphosate herbicide.

A comparative study of eleven protein systems in tamarins, genus Saguinus (Platyrrhini, Callitrichinae)

The genetic variability of six tamarin taxa, genus Saguinus, was analyzed comparatively using protein data from eleven systems coded by 15 loci. S. fuscicollis weddelli and S. midas midas were the most polymorphic taxa, and S. bicolor the least. The results of the phylogenetic analyses (UPGMA and neighbor-joining) and the genetic distances between taxa were generally consistent with their geographic and probable phylogenetic relationships. Analyses of the S. bicolor and S. midas populations suggested that they represent no more than three subspecies of a single species, S. midas, with the bicolor forms belonging to a single subspecies, S. midas bicolor. If supported by additional studies, this would have important implications for the conservation of the bicolor form, which is endangered with extinction. The genetic similarity of S. fuscicollis and S. mystax was also consistent with their geographical and morphological proximity, although more data from a larger number of taxa will be required before the taxonomic relationships within the genus can be defined.