ESTGV - DMAT - Artigo em revista científica, indexada ao WoS/Scopus
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- Orthogonality and closure operatorsPublication . Sousa, LurdesGiven a full and replete subcategory A of a category X, we present a new closure operator, which allows a characterization of the class of all morphisms to which A is orthogonal and of the orthogonal hull of A by means of density and closedness, respectively. Using this characterization, we obtain, inter alia, conditions under which the orthogonal hull coincides with the reflective hull of A. We also explore the relationship between the closure operator introduced here and the regular closure operator.
- Solid hulls of concrete categoriesPublication . Sousa, LurdesThis paper deals with the problem of the existence of solid hulls for concrete categories. Sufficient conditions are given for the existence of a solid hull of a concrete category. For concrete categories over Set with a small finally dense subcategory, we show that the existence of solid hulls is equivalent to Weak Vopenka's Principle.
- α-sober spaces via the orthogonal closure operatorPublication . Sousa, LurdesEach ordinal alpha equipped with the upper topology is a T0-space. It is well known that for alpha=2 the reflective hull of alpha in Top0 is the subcategory of sober spaces. Here, we define alpha-sober space for every ordinal alpha in such a way that the reflective hull of alpha in Top0 is the subcategory of alpha-sober spaces. Moreover, we obtain an order-preserving bijective correspondence between a proper class of ordinals and the corresponding (epi)reflective hulls. Our main tool is the concept of orthogonal closure operator, introduced by the authour in a previous paper.
- Note on multisolid categoriesPublication . Sousa, LurdesIt is shown that a cowellpowered concrete category (A,U) over a multicocomplete category is multisolid if and only if A is multicocmplete and U is a right multi-adjoint.
- Constructions of Solid HullsPublication . Adámek, Jirí; Sousa, LurdesFor each concrete category (K,U) an extension LIM(K,U) is constructed and under certain ‘smallness conditions’ it is proved that LIM(K,U) is a solid hull of (K,U), i.e., the least finally dense solid extension of (K,U). A full subcategory of Top_2 is presented which does not have a solid hull.
- Conical differentiability for bone remodeling contact rod modelsPublication . Figueiredo, Isabel; Leal, Carlos; Pinto, CecíliaWe prove the conical differentiability of the solution to a bone remodeling contact rod model, for given data (applied loads and rigid obstacle), with respect to small perturbations of the cross section of the rod. The proof is based on the special structure of the model, composed of a variational inequality coupled with an ordinary differential equation with respect to time. This structure enables the verification of the two following fundamental results: the polyhedricity of a modified displacement constraint set defined by the obstacle and the differentiability of the two forms associated to the variational inequality.
- Shape analysis of an adaptive elastic rod modelPublication . Figueiredo, Isabel; Leal, Carlos; Pinto, CecíliaWe analyze the shape semiderivative of the solution to an asymptotic nonlinear adaptive elastic rod model, derived in Figueiredo and Trabucho [Math. Mech. Solids, 9 (2004), pp. 331–354], with respect to small perturbations of the cross section. The rod model is defined by generalized Bernoulli–Navier elastic equilibrium equations and an ordinary differential equation with respect to time. Taking advantage of the model’s special structure and the regularity of its solution, we compute and completely identify, in an appropriate functional space involving time, the weak shape semiderivative
- Multi-attribute choice with ordinal information: a comparison of different decision rulesPublication . Sarabando, Paula; Dias, LuísIn the context of additive multiattribute aggregation, we address problems with ordinal information, i.e., considering a ranking of the weights (the scaling coefficients). Several rules for ranking alternatives in these situations have been proposed and compared, such as the rank-order-centroid weight, minimum value, central value, and maximum regret rules. This paper compares these rules, together with two rules that had never been studied (quasi-dominance and quasi-optimality) that use a tolerance parameter to extend the concepts of dominance and optimality. Another contribution of this paper is the study of the behavior of these rules in the context of selecting a subset of the most promising alternatives. This study intends to provide guidelines about which rules to choose and how to use them (e.g., how many alternatives to retain and what tolerance to use), considering the contradictory goals of keeping a low number of alternatives yet not excluding the best one. The comparisons are grounded on Monte Carlo simulations.
- Simple procedures of choice in multicriteria problems without precise information about the alternatives’ valuesPublication . Sarabando, Paula; Dias, Luís
- Spontaneous Fluctuations between Diagnostic and Nondiagnostic ECGs in Brugada Syndrome Screening: Portuguese Family with Brugada SyndromePublication . Santos, Luis Ferreira dos; Correia, Emanuel; Rodrigues, Bruno; Nunes, Luis; Costa, António; Carvalho, José Lopes; Elvas, Luis; Henriques, Carla; Matos, Ana; Santos, Jorge OliveiraBACKGROUND: All family members of patients with Brugada syndrome (BS) should be screened. Fluctuations between diagnostic and nondiagnostic electrocardiogram (ECG) patterns in patients with BS are recognized, but systematic studies are lacking. The objective of this work was to prospectively evaluate the spontaneous changes between diagnostic and nondiagnostic ECG patterns in a family screened for BS. METHODS: One hundred twenty-nine family members were possibly affected plus the index case were screened with two ECGs with an interval of 6 months. Only coved-type ECG pattern was defined as diagnostic; type 2 and 3 ECGs were considered suggestive. RESULTS: The first ECG series made six diagnostics and the second 11, but only three patients maintained the diagnostic ECG. Patients with basal diagnostic ECG were older and more frequently symptomatic. Body mass index (BMI) was significantly lower in adults with diagnostic plus suggestive ECG when compared with the others. No significant gender difference was found among relatives with or without diagnostic ECG. CONCLUSION: Spontaneous phenotypic manifestation of BS was more frequent in older symptomatic patients, absent in children, and related with low BMI. ECG manifestations were intermittent in more than 3/4 of the affected patients. Fluctuations between diagnostic and nondiagnostic ECGs may have an implication on the correct phenotyping in family screening so several ECGs with drug challenging are mandatory.
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