11,213 research outputs found

    Identification of mechanisms involved in mastitis response by means of gene network building.

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    Mastitis, an inflammation of the mammary gland, is the most prevalent and costly production disease in dairy herds worldwide. It is caused generally by bacteria and accounts for a significant decrease in milk production and quality. One promising approach to reduce problems caused by mastitis, in addition to sanitary care, is the selection of animals resistant to disease and the incorporation of this trait into the herds. Therefore, studies to better understand the mechanisms involved in animal response to this disease are essential to the proposition of new advances in area. In this context, the aim of this study was to identify groups of genes involved in cow response to mastitis infection, through gene network building from microarray data. Gene expression data from the GeneChipâ Bovine Genome Array (Affymetrix) hybridization with milk somatic cells samples from Holstein-Zebu crossbreed dairy cows, obtained before (B) and 24 hrs after (A) artificial infection with Staphylococcus agalactiae, were analyzed using a network building methodology based on gene co-expression. We used WGCNA (Weighted Gene Co-expression Analysis), a systems biology method for describing the correlation patterns among genes across microarray samples, that can be used for finding clusters (modules) of highly correlated genes to identify modules of co-expressed genes, which may correspond to functionally related genes. By comparing two networks (between contrasting data sets), conserved and non-conserved modules can be identified. This strategy, named differential network analysis, aims to identify genes groups that are both differentially expressed and differentially connected, and changes in connectivity may correspond to large-scale rewiring, in response to environmental changes and/or physiologic perturbations. Two microarray data sets, B (n=5) and A (n=5), were preprocessed using affy and gcrma R/Bioconductor packages. A filter was applied, which resulted in the use of only those transcripts present in all samples. Gene co-expression networks were identified separately for each group (B and A), by the R/WGCNA package. Gene networks were compared between the two groups, and non-conserved modules were uncovered from a correlation test of the connectivity values. Our analysis identified a total of 17 modules of co-expressed genes, three of them, designed by the colors grey (n=35), blue (n=37) and turquoise (n=192), non-conserved between the groups. Using Blast2GO for enrichment analysis, we find the molecular function Protein Binding overrepresented in all three modules. However, in despite of the same molecular function, each one of the modules showed distinct characteristcs. Genes of grey module (BTG3, CD3E, MBD1, CHIC2, PLXNA3, MOCS3, NEIL1, VPS45, BCL2) were related to apoptosis and antigen recognition. Genes of turquoise module were enriched in inflammation mediators, including known mastitis marker genes (FGL1, GJA1, F2RL1, PTPRF, S100A2, TGFB2). The blue one uncovered genes involved in cell division and inflammatory response (CD97, MAD2L1, ZFP106, CDKN2C, LOC514364, NOP14, PCBD1, LOC100139798, AP1S1, EDN1, IL1B, ANXA11). Our study identified some mechanisms (represented by gene modules) that have changed in cows in early response to mastitis infection. Further analysis are being carried out, based on these results, to advance the understanding of animals response to the disease, which can lead to identify the candidate genes that could be used in breeding programs.X-MEETING 2011

    Assembly of lightweight sandwich panels through joining by forming

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    This paper is focused on the assembly of lightweight sandwich panels built upon the patented ‘Opencell’ structure concept. The objective is to investigate the possibility of joining the connection members of the core to the adjoining skin sheet by plastic deformation at ambient temperature, instead of welding or adhesive bonding. The methodology draws from earlier developments of the authors in joining by forming using the mortise-and-tenon concept to experimentation and finite element modelling of the assembly process in unit cells that are representative of the sandwich panels. It is shown that replacing welding by joining by forming allows fabricating sandwich panels from sheet materials that are difficult or impossible to weld while preventing thermal cycles that are responsible for causing metallurgical changes, distortions, and residual stresses. Replacing adhesive bonding by joining by forming circumvents the need of surface preparation, time for the adhesive to cure and environmental compliance, among other requirementsinfo:eu-repo/semantics/publishedVersio

    New results for the t-J model in ladders: Changes in the spin liquid state with applied magnetic field. Implications for the cuprates

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    Exact Diagonalization calculations are presented for the t-J model in the presence of a uniform magnetic field. Results for 2xL ladders (L=8,10,12) and 4x4 square clusters with 1 and 2 holes indicate that the diamagnetic response to a perpendicular magnetic field tends to induce a spin liquid state in the spin background. The zero-field spin liquid state of a two-leg ladder is reinforced by the magnetic field: a considerable increase of rung antiferromagnetic correlations is observed for J/t up to 0.6, for 1 and 2 holes. Pair-breaking is also clearly observed in the ladders and seems to be associated in part with changes promoted by the field in the spin correlations around the zero-field pair. In the 4x4 cluster, the numerical results seem to indicate that the field-induced spin liquid state competes with the zero-field antiferromagnetic short-range-order, the spin liquid state being favored by higher doping and smaller values of J/t. It is interesting to note that the field-effect can also be observed in a 2x2 plaquette with 1 and 2 holes. This opens up the possibility of gaining a qualitative understanding of the effect.Comment: 16 pages, 7 figures, latex New results adde

    The long delayed solution of the Bukhvostov Lipatov model

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    In this paper I complete the solution of the Bukhvostov Lipatov model by computing the physical excitations and their factorized S matrix. I also explain the paradoxes which led in recent years to the suspicion that the model may not be integrable.Comment: 9 page

    Épocas e intensidades de poda de frutificação na goiabeira 'Paluma', em Pinheiros-ES.

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    Este trabalho teve como objetivo avaliar os efeitos de diferentes intensidades de poda de frutificação realizadas em diferentes épocas do ano sobre a fenologia e a produção da goiabeira ?Paluma?, em Pinheiros-ES. As plantas foram submetidas a três intensidades de poda de frutificação (curta, média e longa), em quatro diferentes épocas (25-11-2005, 21-12-2005, 27-01-2006 e 23-02-2006). O ciclo da goiabeira ?Paluma?, entre a poda até o início da colheita dos frutos, variou de 189 dias (podas em novembro e dezembro) a 203 dias (poda em fevereiro). Independentemente da época de poda, as plantas submetidas à poda longa apresentaram maior emissão de brotos novos e maior número de ramos estabelecidos. As plantas submetidas à poda curta apresentaram menores números de brotos emitidos e de ramos estabelecidos, bem como menor índice de pegamento de frutos, menor número de frutos por planta e, conseqüentemente, menor produção; entretanto produziram frutos de maior peso médio em relação às plantas submetidas à poda longa. A maior produção e o maior número de frutos colhidos por planta ocorreram nas plantas podadas em fevereiro. A época e a intensidade da poda de frutificação afetam a brotação e a produção da goiabeira ?Paluma?. Termos para indexação: Psidium guajava L., fenologia, produção de frutos

    Effects of coastal orientation and depth on the distribution of subtidal benthic assemblages

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    Copyright © 2013 Blackwell Verlag GmbH.A better understanding of biological systems can only be gained if we understand what processes are important and how they operate to determine the distribution of organisms. Coastal orientation and depth can influence environmental conditions, including the degree of water motion and availability of light, which in turn may influence the horizontal and vertical patterns of organism distribution. Here, we used a mixed-model design to examine the effects of coastal orientation and depth on the structure of benthic assemblages by comparing the abundance and distribution of macroalgae and invertebrates in shallow and deep waters on the opposing coasts of Sa˜o Miguel. Generally, coastal orientation had little influence on the distribution of most taxa. In contrast, significant differences were generally associated with depth, although patterns were spatially variable at the scale of locations. This study suggests that depth, and processes operating at the scale of location, but not at the scale of the coast, have an important influence on these assemblages, and that failure to recognise such a scale of variability may hamper our ability to better understand the processes that structure these communities

    Avaliação da atividade antimicrobiana de espécies de Lippia frente à Aeromonas hydrophila por bioautografia indireta.

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    O objetivo deste estudo foi avaliar a atividade antibacteriana de frações isoladas do óleo essencial de diferentes espécies de Lippia (Lippia origanoides e Lippia sidoides) frente à A. hydrophila por bioautografia indireta

    Consumers affective and emotional responses to yogurt across different socio-economic status.

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    The use of hedonic measures is not enough to characterize consumers? affective responses to food products and to discriminate among samples. Thus, understanding emotional responses to products can be useful in the product development process. Individual characteristics, such as socio-economic status SES, are expected to modulate emotional responses to food. The aim of the study was to investigate the influence of socio-economic status on consumers? liking and emotional responses to yogurts.SLACA, 12. De 4 a 7 de Novembro de 2017. Ref. 71234

    A self-clinching fastener for hidden lap joints

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    This paper presents a new self-clinching fastener to connect two sheets (or plates), made from similar or dissimilar materials, placed over one another by means of a mechanical form-closed joint that is hidden inside the sheets. The development of the fastener, the definition of its main design variables and the identification of its workability limits are carried out by means of a combined experimental and numerical simulation work based on finite elements. It is shown that self-clinching by pressing the two overlapped sheets against each other to displace material around the annular groove of the fastener shank and create undercuts in both sheets requires an appropriate choice of the design variables. Wrong values of the design variables resulting in lack or excess of material displaced by plastic flow gives rise to inappropriate lap joints that cannot be used in production. The new proposed fastener allows, for the first time ever, joining by forming with the use of auxiliary elements that are harder than the sheet materials to fabricate invisible joints with no material protrusions in applications requiring minimum installation spaceinfo:eu-repo/semantics/publishedVersio
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