4,569 research outputs found

    Quadrados mínimos parciais uni e multivariado aplicados na seleção genômica para características de carcaça em suínos.

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    A principal contribuição da genética molecular é a utilização direta das informações de DNA no processo de identifi cação de indivíduos geneticamente superiores. Sob esse enfoque, idealizou-se a seleção genômica ampla (Genome Wide Selection - GWS), a qual consiste na análise de marcadores SNPs (Single Nucleotide Polymorphisms) amplamente distribuídos no genoma. Devido a esse grande número de SNPs, geralmente maior que o número de indivíduos genotipados, e à alta colinearidade entre eles, métodos de redução de dimensionalidade são requeridos. Dentre estes, destaca-se o método de regressão via Quadrados Mínimos Parciais (Partial Least Squares - PLS), que além de solucionar tais problemas, permite uma abordagem multivariada, considerando múltiplos fenótipos. Diante do exposto, objetivouse aplicar e comparar a regressão PLS univariada (UPLS) e multivariada (MPLS) na GWS para características de carcaça em uma população F2 de suínos Piau×Comercial. Os resultados evidenciaram a superioridade do método MPLS, uma vez que este proporcionou maiores valores de acurácia em relação à abordagem univariada

    Perfil de expressão gênica global no músculo esquelético de ovinos por meio de microarrays.

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    O perfil de expressão gênica global no músculo esquelético de cordeiros de quatro grupos genéticos de ovinos foi comparado por meio de microarrays de oligonucleotídeos. As análises indicaram 262 transcritos diferencialmente expressos entre os grupos genéticos. Um total de 23 transcritos de funções conhecidas foram diferencialmente expressos, sendo dez deles apenas na comparação Morada Nova x Somalis Brasileira. Dentre os genes diferencialmente expressos, aqueles envolvidos com características de importância para a produção de carne, destacaram-se: MyoD e IGFBP4 (desenvolvimento muscular), PGDS e SCD (biosíntese de ácidos graxos), C/EBP δ e PPARγ (adipogênese) e PYGL, GLUT-3, GGTA1 e ATP5G1 (metabolismo energético). Os resultados da técnica de microarray foram validados por meio de qPCR. Estes transcritos podem ser considerados marcadores expressos úteis para a seleção de cordeiros nas condições estudadas. A seleção para polimorfismos nestes genes pode conferir maior marmoreio e deposição de massa muscular, que são características ligadas diretamente a quantidade, a qualidade e a aceitação da carne. Global gene expression profile in skeletal muscle of sheep by microarray. Abstract: The global gene expression profile in muscle of four genetic groups of hair sheep were compared by oligonucleotide microarray. The analyses showed that 262 transcripts were differentially expressed among the four genetic groups. A total of 23 genes of known function were differentially expressed, with 10 transcripts differentially expressed only in the comparison between Morada Nova x Brazilian Somali. Among the differentially expressed genes, those involved with important features for the production of meat, stood out: IGFBP4 and MyoD (muscle growth), and PGDS (SCD biosynthesis of fatty acids), C/EBPδ and PPARγ (adipogenesis) and PYGL, GLUT-3, and GGTA1 ATP5G1 (energy metabolism). The results of the microarray were validated by qPCR. These transcripts can be considered useful markers expressed in the selection of lambs under the conditions studied here. Screening for polymorphisms in these genes may confer greater marbling deposition and muscle mass, which are features directly linked to quantity, quality and acceptability of meat

    Evaluation of quality and yield of sugarcane (Saccharum officinarum) CB 47-355 variety to animal feeding in Porto Velho, Northern Brazil.

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    The aim of this study was to evaluate of quality and yield of sugarcane CB 47-355 variety, under conditions of Northern Brazil, in Porto Velho, RO. O objetivo deste estudo foi avaliar a qualidade e produtividade da cana CB 47-355 variedade, sob condições do Norte do Brasil, em Porto Velho, RO

    Properties of magnetic nanodots with perpendicular anisotropy

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    Nanodots with magnetic vortices have many potential applications, such as magnetic memories (VRAMs) and spin transfer nano-oscillators (STNOs). Adding a perpendicular anisotropy term to the magnetic energy of the nanodot it becomes possible to tune the vortex core properties. This can be obtained, e.g., in Co nanodots by varying the thickness of the Co layer in a Co/Pt stack. Here we discuss the spin configuration of circular and elliptical nanodots for different perpendicular anisotropies; we show for nanodisks that micromagnetic simulations and analytical results agree. Increasing the perpendicular anisotropy, the vortex core radii increase, the phase diagrams are modified and new configurations appear; the knowledge of these phase diagrams is relevant for the choice of optimum nanodot dimensions for applications. MFM measurements on Co/Pt multilayers confirm the trend of the vortex core diameters with varying Co layer thicknesses.Comment: 7 pages, 8 figure

    Desafios do manejo integrado de pragas da soja no Brasil Central.

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    Este trabalho pretende: 1) apresentar aspectos relacionados à adoção da tecnologia do MIP pelos agricultores, numa região produtora de Goiás; 2) identificar fatores que interferem na adoção de tecnologias nas lavouras; 3) inferir sobre aspectos da transferência de tecnologias para a sustentabilidade da agricultura, no Sudoeste Goiano.bitstream/CNPAF/26716/1/comt_149.pd

    Cannibalism and virus production in Spodoptera frugiperda (J. E. smith) (Lepidoptera: noctuidae) larvae fed with two leaf substrates inoculated with baculovirus spodoptera.

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    Cannibalism in the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) (FAW), is a limiting factor in a baculovirus production system. To detect the impact of cannibalism, a two-step bioassay was conducted with different larval ages of FAW fed on two food sources (corn and castor bean leaves) contaminated with the S. frugiperda multiple-embedded nucleopolyhedrovirus. In a first bioassay, the food source affected the cannibalism, being higher for all larval ages tested (5-, 6- and 7-day-old larvae) in larvae fed on corn than on those fed on castor bean leaves. Larval mortality, weight equivalent and larval equivalents (LEs) per hectare decreased as the larval age increased. Larval weight, occlusion bodies (OBs)/larva and total OBs increased when the larval age increased. In a second bioassay, in which only 6-and 7-day-old larvae were used because of the performance in the first bioassay, the cannibalism rates were affected by the interaction between food sources and time of feeding (48 and 72 h), reaching the highest values for 6- and 7-day-old larvae fed on corn leaves for 72 h. Mortality of the FAW was affected by the interaction between food sources, larval age and time of feeding. The lowest mortalities were on 7-day-old larvae when they were fed on castor bean leaves for 48 and 72 h. Larval weight, OBs/larva, total OBs and LEs were affected by theinteraction between food sources and larval age. A significant correlation was observed between larval weight and OBs/larva that fed on both food sources, suggesting that larval weight can be used to achieve a concentration to be sprayed in 1 ha

    Comparison of dimensionality reduction methods to predict genomic breeding values for carcass traits in pigs.

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    A significant contribution of molecular genetics is the direct use of DNA information to identify genetically superior individuals. With this approach, genome-wide selection (GWS) can be used for this purpose. GWS consists of analyzing a large number of single nucleotide polymorphism markers widely distributed in the genome; however, because the number of markers is much larger than the number of genotyped individuals, and such markers are highly correlated, special statistical methods are widely required. Among these methods, independent component regression, principal component regression, partial least squares, and partial principal components stand out. Thus, the aim of this study was to propose an application of the methods of dimensionality reduction to GWS of carcass traits in an F2 (Piau x commercial line) pig population. The results show similarities between the principal and the independent component methods and provided the most accurate genomic breeding estimates for most carcass traits in pigs
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