Forbidden subgraphs and the König-Egerváry property

The matching number of a graph is the maximum size of a set of vertex-disjoint edges. The transversal number is the minimum number of vertices needed to meet every edge. A graph has the König-Egerváry property if its matching number equals its transversal number. Lovász proved a characterization of graphs having the König-Egerváry property by means of forbidden subgraphs within graphs with a perfect matching. Korach, Nguyen, and Peis proposed an extension of Lovász's result to a characterization of all graphs having the König-Egerváry property in terms of forbidden configurations (which are certain arrangements of a subgraph and a maximum matching). In this work, we prove a characterization of graphs having the König-Egerváry property by means of forbidden subgraphs which is a strengthened version of the characterization by Korach et al. Using our characterization of graphs with the König-Egerváry property, we also prove a forbidden subgraph characterization for the class of edge-perfect graphs. © 2013 Elsevier B.V. All rights reserved.Fil:Bonomo, F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Durán, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Grippo, L.N. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Safe, M.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Innovative therapeutic approaches for the treatment of myocardial ischemia and angina

Cardiac energy metabolism is complex and has three main components: 1. Substrate utilisation, 2 Oxydative phosphorilation and 3. Transfer of high energy phosphates. Substrate utilization involves the cellular uptake of free fatty acids, glucose and amino acids, their breakdown by beta-oxidation and glycolysis, and the entry of Acetyl Coenzyme A into the Krebs cycle. Oxidative phosphorylation involves the production of energy by the mitochondrial respiratory chain and the production of high-energy phosphates. Until recent it was not known that it was possible to delimitate the infarct size through therapeutic interventions. Likely, the improvement to understand the mechanisms of cellular survivor occurs in that year, when Murry et al. discovered an intrinsic mechanism of myocardial protection, which they denominated as ischemic preconditioning. In that experiment, it was observed that four cycles of five minutes of ischemia, with intermittent reperfusion, before 40 min of ischemia period, resulted in reduction of 75% of the infarct size. Also, it was demonstrated by these researches that this protection it was not resulted by collateral overture and that protective effect of the ischemic preconditioning was abolished in the presence of prolonged ischemia, with duration of 3 h. Two phenomenons, the walk-through angina and the warm up phenomenon could represent a clinical manifestation of preconditioning. The phenomenon of walk-through angina was first related in the end of century XVIII in a patient that developed angina during the effort, but experimented the paradox disappearing of the pain with the exercise continuation. The exact molecular mechanisms involved in ischemic preconditioning are not fully elucidated. Therefore, due to the high prevalence of risk factors to cardiovascular diseases and the high morbidity and mortality associated with coronary artery disease, there is a needed to understand even better the cardiac metabolism during ischemia and the strategies to reduce the consequences of the ischemia, to preserve the viability of the ischemic myocardium

Convexity in partial cubes: the hull number

We prove that the combinatorial optimization problem of determining the hull number of a partial cube is NP-complete. This makes partial cubes the minimal graph class for which NP-completeness of this problem is known and improves some earlier results in the literature. On the other hand we provide a polynomial-time algorithm to determine the hull number of planar partial cube quadrangulations. Instances of the hull number problem for partial cubes described include poset dimension and hitting sets for interiors of curves in the plane. To obtain the above results, we investigate convexity in partial cubes and characterize these graphs in terms of their lattice of convex subgraphs, improving a theorem of Handa. Furthermore we provide a topological representation theorem for planar partial cubes, generalizing a result of Fukuda and Handa about rank three oriented matroids.Comment: 19 pages, 4 figure

Evaluation of demands of inclusion, exclusion and alteration of technologies in the Brazilian Health System submitted to the National Committee on Technology Incorporation

ABSTRACT The steady increase in the number of health technologies and advances in associated research generate management challenges in the choice of technologies to be made available to the public. From 2011, the process of inclusion, exclusion and alteration of technologies to the Brazilian Unified Health System (SUS) has undergone major transformations, such as the creation of the National Committee on Technology Incorporation (CONITEC). This study analyzed the decisions of CONITEC since its inception until July 2015. The analyzed variables were: type of technology, reason for application, name of the technology, indication, claimant and CONITEC decision status. We found that the Government was the main claimant, accounting for 58.1% of the 420 cases. The most frequent request was inclusion (93.8%) and the technology type was medicine (61.4%). Of the incorporated medicines, the classes of antineoplastic/immunomodulatory were the most frequent (39.47%). Society's desire for inclusion of an increasing amount of health technology contrasts with the limited resources available to management, which causes budget concerns. Using Health Technology Assessment (HTA), advances resulting from these innovations in the process were highlighted, and challenges were identified for the management and the academic community

Um balanço das políticas do governo Lula para a educação superior: continuidade e ruptura

Resumo O trabalho apresenta e analisa as principais políticas para o setor privado de educação superior adotadas pelo governo de Luiz Inácio Lula da Silva (2003/2010). A partir de uma retrospectiva histórica e de uma análise de sua implementação, as políticas são consideradas por meio de uma revisão crítica da literatura e dos dados oficiais. O trabalho demonstra que, apesar de ter realizado políticas para o setor público bastante distintas das do governo de Fernando Henrique Cardoso, no caso do setor privado, há antes um aprofundamento das opções políticas já desenvolvidas durante o governo de Cardoso. Essas opções se traduzem em ações de fomento ao desenvolvimento do setor privado, na medida em que ampliaram o financiamento deste e consolidaram um marco legal que proporcionou segurança jurídica às mantenedoras. Esse fomento, entretanto, veio acompanhado de um sensível aumento e aperfeiçoamento dos mecanismos de controle sobre o crescimento do setor privado

Polynomial Time Algorithms for Computing a Minimum Hull Set in Distance-Hereditary and Chordal Graphs

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