774 research outputs found
Estimativas de parâmetros genéticos para características reprodutivas e de crescimento em bovinos da raça Canchim.
Estudou-se neste trabalho dados referentes às características de idade ao segundo parto (ISP), perímetro escrotal aos 420 dias de idade (PE420) e peso aos 420 dias de idade de machos e fêmeas (P420) de animais da raça Canchim, para as quais foram obtidas estimativas de herdabilidade e correlações genéticas. No modelo animal, foram incluídos os efeitos fixos de grupo de contemporâneos e os efeitos aleatórios aditivos diretos e residuais. Utilizou-se o método da máxima verossimilhança restrita em análise bi-característica. As médias de ISP, PE420 e P420 foram iguais a 57,07±8,69 meses, 24,63±3,84 cm e 260,37±46,5l kg, respectivamente. As estimativas de herdabilidade foram 0,07±0,01, 0,2l±0,05 e 0,24±0,03, respectivamente para ISP, PE420 e P420. As correlações genéticas foram iguais a -0,47 (ISPXPE420) e 0,10 (ISPxP420). A seleção direta para perímetro escrotal aos 420 dias de idade poderá resultar em progresso genético favoráveis na assiduidade reprodutiva de fêmeas da raça Canchim, considerando que o PE420 apresentou correlação genética aditiva com idade ao segundo parto
Estimativas de componentes de variância e herdabilidade para características reprodutivas e de crescimento em bovinos da raça Canchim.
Estudou-se neste trabalho dados referentes às características de idade ao primeiro parto (lPP), idade ao segundo parto (ISP), perímetro escrotal aos 420 dias de idade (PE420) e peso aos 420 dias de idade de machos e fêmeas (P420) de animais da raça Canchim, para as quais foram obtidas estimativas de herdabilidade. No modelo animal, foram incluídos os efeitos fixos de grupo de contemporâneos e os efeitos aleatórios aditivos diretos e residuais. Empregou-se o método da máxima verossimilhança restrita em análise uni-característica. As médias observadas de IPP, ISP, PE420 e P420 foram iguais a 39,47±7,20 meses, 57,08±8,79 meses, 24,63±3,84 cm e 260,37±46,5l kg, respectivamente. As herdabilidades foram iguais a 0,03±0,Ol, 0,07±0,Ol, 0,22±0,05 e 0,24±0,03 para IPP, ISP, PE420 e P420, respectivamente. Dentre as características reprodutivas e de crescimento estudadas o perímetro escrotal e o peso aos 420 dias de idade apresentaram estimativas de herdabilidade de moderada magnitude, indicando que a seleção para estas características poderá contribuir para o melhoramento genético da raça Canchim
ITS-rDNA phylogeny of Colletotrichum spp. causal agent of apple glomerella leaf spot.
Several diseases have affected apple production, among them there is Glomerella leaf spot (GLS) caused by Colletotrichum spp. The first report of this disease in apple was in plants nearby citrus orchards in São Paulo State, Brazil. The origin of this disease is still not clear, and studies based on the molecular phylogeny could relate the organisms evolutionarily and characterize possible mechanisms of divergent evolution. The amplification of 5.8S-ITS (Internal Transcribed Spacer) of rDNA of 51 pathogenic Colletotrichum spp. isolates from apples, pineapple guava and citrus produced one fragment of approximately 600 bases pairs (bp) for all the isolates analyzed. The amplified fragments were cleaved with restriction enzymes, and fragments from 90 to 500bp were obtained. The sequencing of this region allowed the generation of a phylogenetic tree, regardless of their hosts, and 5 isolated groups were obtained. From the "in silico" comparison, it was possible to verify a variation from 93 to 100% of similarity between the sequences studied and the Genbank data base. The causal agent of GLS is nearly related (clustered) to isolates of pineapple guava and to the citrus isolates used as control
Nervous system and computation.
none5Computational systems are useful in neuroscience in many ways. For instance, they may be used to construct maps of brain structure and activation, or to describe brain processes mathematically.Furthermore, they inspired a powerful theory of brain function, in which the brain is viewed as a system characterized by intrinsic computational activities or as a "computational information processor." Although many neuroscientists believe that neural systems really perform computations, some are more cautious about computationalism or reject it. Thus, does the brain really compute? Answering this question requires getting clear on a definition of computation that is able to draw a line between physical systems that compute and systems that do not, so that we can discern on which side of the line the brain (or parts of it) could fall. In order to shed some light on the role of computational processes in brain function, available neurobiological data will be summarized from the standpoint of a recently proposed taxonomy of notions of computation, with the aim of identifying which brain processes can be considered computational. The emerging picture shows the brain as a very peculiar system, in which genuine computational features act in concert with noncomputational dynamical processes, leading to continuous self-organization and remodeling under the action of external stimuli from the environment and from the rest of the organism.openD. Guidolin; G. Albertin; M. Guescini; K. Fuxe; L.F. Agnati LF.D., Guidolin; G., Albertin; Guescini, Michele; K., Fuxe; L. F. Agnati L., F
Learning to Generate Ambiguous Sequences
In this paper, we experiment with methods for obtaining
binary sequences with a random probability mass function and with low autocorrelation and use it to generate ambiguous outcomes.
Outputs from a neural network are mixed and shuffled, resulting in binary sequences whose probability mass function is non-convergent, constantly moving and changing.
Empirical comparison with algorithms that generate ambiguity shows that the sequences generated by the proposed method have a significantly lower serial dependence. Therefore, the method is useful in scenarios
where observes can see and record the outcome of each draw sequentially, by hindering the ability to make useful statistical inferences
Synthesising Corporate Responsibility on Organisational and Societal Levels of Analysis: An Integrative Perspective
This article develops an integrative perspective on corporate responsibility by synthesising competing perspectives on the responsibility of the corporation at the organisational and societal levels of analysis. We review three major corporate responsibility perspectives, which we refer to as economic, critical, and politico-ethical. We analyse the major potential uses and pitfalls of the perspectives, and integrate the debate on these two levels. Our synthesis concludes that when a society has a robust division of moral labour in place, the responsibility of a corporation may be economic (as suggested under the economic perspective) without jeopardising democracy and sustainability (as reported under the critical perspective). Moreover, the economic role of corporations neither signifies the absence of deliberative democratic mechanisms nor business practices extending beyond compliance (as called for under the politico-ethical perspective). The study underscores the value of integrating different perspectives and multiple levels of analysis to present comprehensive descriptions and prescriptions of the responsibility phenomenon
Linear Predictability vs. Bull and Bear Market Models in Strategic Asset Allocation Decisions: Evidence from UK Data
Most papers in the portfolio choice literature have examined linear predictability frameworks based on the idea that simple but flexible Vector Autoregressive (VAR) models can be expanded to produce portfolio allocations that hedge against the bull and bear dynamics typical of financial markets through careful selection of predictor variables that capture business cycles and market sentiment. Yet, a distinct literature exists that shows that nonlinear econometric frameworks, such as Markov switching, are also natural tools to compute optimal portfolios arising from the existence of good and bad market states. This paper examines whether and how simple VARs can produce portfolio rules similar to those obtained under a simple Markov switching, by studying the effects of expanding both the order of the VAR and the number/selection of predictor variables included. In a typical stock-bond strategic asset allocation problem for U.K. data, we compute the out-of-sample certainty equivalent returns for a wide range of VARs and compare these measures of performance with those of nonlinear models. We conclude that most VARs cannot produce portfolio rules, hedging demands, or (net of transaction costs) out-of-sample performances that approximate those obtained from equally simple nonlinear frameworks
A point mutation in cpsE renders Streptococcus pneumoniae nonencapsulated and enhances its growth, adherence and competence.
BACKGROUND: The polysaccharide capsule is a major virulence factor of the important human pathogen Streptococcus pneumoniae. However, S. pneumoniae strains lacking capsule do occur.
RESULTS: Here, we report a nasopharyngeal isolate of Streptococcus pneumoniae composed of a mixture of two phenotypes; one encapsulated (serotype 18C) and the other nonencapsulated, determined by serotyping, electron microscopy and fluorescence isothiocyanate dextran exclusion assay.By whole genome sequencing, we demonstrated that the phenotypes differ by a single nucleotide base pair in capsular gene cpsE (C to G change at gene position 1135) predicted to result in amino acid change from arginine to glycine at position 379, located in the cytoplasmic, enzymatically active, region of this transmembrane protein. This SNP is responsible for loss of capsule production as the phenotype is transferred with the capsule operon. The nonencapsulated variant is superior in growth in vitro and is also 117-fold more adherent to and more invasive into Detroit 562 human epithelial cells than the encapsulated variant.Expression of six competence pathway genes and one competence-associated gene was 11 to 34-fold higher in the nonencapsulated variant than the encapsulated and transformation frequency was 3.7-fold greater.
CONCLUSIONS: We identified a new single point mutation in capsule gene cpsE of a clinical S. pneumoniae serotype 18C isolate sufficient to cause loss of capsule expression resulting in the co-existence of the encapsulated and nonencapsulated phenotype. The mutation caused phenotypic changes in growth, adherence to epithelial cells and transformability. Mutation in capsule gene cpsE may be a way for S. pneumoniae to lose its capsule and increase its colonization potential
Different spatial distribution of inflammatory cells in the tumor microenvironment of ABC and GBC subgroups of diffuse large B cell lymphoma
Diffuse Large B-Cell Lymphoma (DLBCL) presents a high clinical and biological heterogeneity, and the tumor microenvironment chracteristics are important in its progression. The aim of this study was to evaluate tumor T, B cells, macrophages and mast cells distribution in GBC and ABC DLBCL subgroups through a set of morphometric parameters allowing to provide a quantitative evaluation of the morphological features of the spatial patterns generated by these inflammatory cells. Histological ABC and GCB samples were immunostained for CD4, CD8, CD68, CD 163, and tryptase in order to determine both percentage and position of positive cells in the tissue characterizing their spatial distribution. The results evidenced that cell patterns generated by CD4-, CD8-, CD68-, CD163- and tryptase-positive cell profiles exhibited a significantly higher uniformity index in ABC than in GCB subgroup. The positive-cell distributions appeared clustered in tissues from GCB, while in tissues from ABC such a feature was lower or absent. The combinations of spatial statistics-derived parameters can lead to better predictions of tumor cell infiltration than any classical morphometric method providing a more accurate description of the functional status of the tumor, useful for patient prognosis
- …
