896 resultados para Positive-p Representation
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In this position paper we propose a consistent and unifying view to all those basic knowledge representation models that are based on the existence of two somehow opposite fuzzy concepts. A number of these basic models can be found in fuzzy logic and multi-valued logic literature. Here it is claimed that it is the semantic relationship between two paired concepts what determines the emergence of different types of neutrality, namely indeterminacy, ambivalence and conflict, widely used under different frameworks (possibly under different names). It will be shown the potential relevance of paired structures, generated from two paired concepts together with their associated neutrality, all of them to be modeled as fuzzy sets. In this way, paired structures can be viewed as a standard basic model from which different models arise. This unifying view should therefore allow a deeper analysis of the relationships between several existing knowledge representation formalisms, providing a basis from which more expressive models can be later developed.
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In this article, a new methodology is presented to obtain representation models for a priori relation z = u(x1, x2, . . . ,xn) (1), with a known an experimental dataset zi; x1i ; x2i ; x3i ; . . . ; xni i=1;2;...;p· In this methodology, a potential energy is initially defined over each possible model for the relationship (1), what allows the application of the Lagrangian mechanics to the derived system. The solution of the Euler–Lagrange in this system allows obtaining the optimal solution according to the minimal action principle. The defined Lagrangian, corresponds to a continuous medium, where a n-dimensional finite elements model has been applied, so it is possible to get a solution for the problem solving a compatible and determined linear symmetric equation system. The computational implementation of the methodology has resulted in an improvement in the process of get representation models obtained and published previously by the authors.
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Tese de mestrado, Biologia Molecular e Genética, Universidade de Lisboa, Faculdade de Ciências, 2016
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Recent scholarship has suggested that nation-states will gradually fade away in favor of regions and super-regions as the main actors within a European Union characterized by strong regional identities. At the same time, recent developments have shown that citizen support for European integration is essential for any future development of the Union. The puzzle inspiring this paper is the finding that the greatest support for the EU increasingly stems from minority nationalist regions seeking to bypass their central states to achieve their policy goals at the EU level. This paper empirically tests this suggestion, while shedding light on the relationship between the quality of representation of regional interests at the EU level and positive citizen attitudes towards the EU. In particular, it finds two explanations for cross-regional variation in the relationship between Euroskepticism and representation: (1) a cultural explanation, embodied by a difference in the nature and quality of representation between regions that are linguistically distinctive and regions that are not; and (2) an institutional explanation, embodied by a difference in the nature and quality of representation between regions from federal and non-federal member states. The paper uses an eclectic methodological approach, first utilizing multivariate regression analysis, estimating logistic and ordinal logit models that help explain variation in Euroskepticism at the regional level. The results are then complemented by the findings of in-depth elite interviews of regional representatives - more specifically the directors of a selection of the many regional information offices present in Brussels. This paper takes the study of Euroskepticism to a new level, as most previous scholarly work has focused on explanations at the individual or at the member state level. At the same time it strengthens the notion of a growing importance of a "Europe of the regions."
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During limb development, expression of the TALE homeobox transcription factor Meis1 is activated by retinoic acid in the proximal-most limb bud regions, which give rise to the upper forelimb and hindlimb. Early subdivision of the limb bud into proximal Meis-positive and distal Meis-negative domains is necessary for correct proximo-distal (P-D) limb development in the chick, since ectopic Meis1 overexpression abolishes distal limb structures, produces a proximal shift of limb identities along the P-D axis, and proximalizes distal limb cell affinity properties. To determine whether Meis activity is also required for P-D limb specification in mammals, we generated transgenic mice ectopically expressing Meis1 in the distal limb mesenchyme under the control of the Msx2 promoter. Msx2:Meis1 transgenic mice display altered P-D patterning and shifted P-D Hox gene expression domains, similar to those previously described for the chicken. Meis proteins function in cooperation with PBX factors, another TALE homeodomain subfamily. Meis-Pbx interaction is required for nuclear localization of both proteins in cell culture, and is important for their DNA-binding and transactivation efficiency. During limb development, Pbx1 nuclear expression correlates with the Meis expression domain, and Pbx1 has been proposed as the main Meis partner in this context; however, we found that Pbx1 deficiency did not modify the limb phenotype of Msx2:Meis1 mice. Our results indicate a conserved role of Meis activity in P-D specification of the tetrapod limb and suggest that Pbx function in this context is either not required or is provided by partners other than Pbx1.
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BACKGROUND Over 3500 HIV-positive women give birth annually in Ukraine, a setting with high prevalence of sexually transmitted infections. Herpes simplex virus Type 2 (HSV-2) co-infection may increase HIV mother-to-child transmission (MTCT) risk. We explored factors associated with HSV-2 seropositivity among HIV-positive women in Ukraine, and its impact on HIV MTCT. METHODS Data on 1513 HIV-positive women enrolled in the Ukraine European Collaborative Study from 2007 to 2012 were analysed. Poisson and logistic regression models respectively were fit to investigate factors associated with HSV-2 seropositivity and HIV MTCT. RESULTS Median maternal age was 27 years (IQR 24-31), 53% (796/1513) had been diagnosed with HIV during their most recent pregnancy and 20% had a history of injecting drugs. Median antenatal CD4 count was 430 cells/mm(3) (IQR 290-580). Ninety-six percent had received antiretroviral therapy antenatally. HSV-2 seroprevalence was 68% (1026/1513). In adjusted analyses, factors associated with HSV-2 antibodies were history of pregnancy termination (APR 1.30 (95% CI 1.18-1.43) for ≥ 2 vs. 0), having an HIV-positive partner (APR 1.15 (95% CI 1.05-1.26) vs partner's HIV status unknown) and HCV seropositivity (APR 1.23 (95 % CI 1.13-1.35)). The overall HIV MTCT rate was 2.80% (95% CI 1.98-3.84); no increased HIV MTCT risk was detected among HSV-2 seropositive women after adjusting for known risk factors (AOR 1.43 (95% CI 0.54-3.77). CONCLUSION No increased risk of HIV MTCT was detected among the 68% of HIV-positive women with antibodies to HSV-2, in this population with an overall HIV MTCT rate of 2.8%. Markers of ongoing sexual risk among HIV-positive HSV-2 seronegative women indicate the importance of interventions to prevent primary HSV-2 infection during pregnancy in this high-risk group.
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Mode of access: Internet.
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"November 1990."
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"Report no. FHWA-TO-80-1."
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Bibliography: p. 121-126.
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Cover title.
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"March 16, 1998."
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Contiene: T. I (LV, 338 p.) -- T. II (442 p.) -- T. III (414 p.)
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At bottom of t.p.: 141.
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Caption title.