157 research outputs found

    Removing zero Lyapunov exponents in volume-preserving flows

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    Baraviera and Bonatti proved that it is possible to perturb, in the c^1 topology, a volume-preserving and partial hyperbolic diffeomorphism in order to obtain a non-zero sum of all the Lyapunov exponents in the central direction. In this article we obtain the analogous result for volume-preserving flows.Comment: 10 page

    Increasing pattern recognition accuracy for chemical sensing by evolutionary based drift compensation

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    Artificial olfaction systems, which mimic human olfaction by using arrays of gas chemical sensors combined with pattern recognition methods, represent a potentially low-cost tool in many areas of industry such as perfumery, food and drink production, clinical diagnosis, health and safety, environmental monitoring and process control. However, successful applications of these systems are still largely limited to specialized laboratories. Sensor drift, i.e., the lack of a sensor's stability over time, still limits real in dustrial setups. This paper presents and discusses an evolutionary based adaptive drift-correction method designed to work with state-of-the-art classification systems. The proposed approach exploits a cutting-edge evolutionary strategy to iteratively tweak the coefficients of a linear transformation which can transparently correct raw sensors' measures thus mitigating the negative effects of the drift. The method learns the optimal correction strategy without the use of models or other hypotheses on the behavior of the physical chemical sensors

    Toward a bioethical issue: induced multiple pregnancies and neonatal outcomes

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    Assisted reproductive technology has made great progress during the last three decades. After the initial enthusiasm, many ethical, legal and social issues related to the application of these procedures began to evolve. Multifetal pregnancy and fetal reduction, embryo cryopreservation, preimplantation genetic diagnosis, risks of birth defects and other adverse outcome associated with assisted reproductive technology are issues that have to be addressed building future collaborative studies and continuing the debate on related ethical issues

    Do children\u27s food preferences align with dietary recommendations?

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    Objectives: To examine how Australian children\u27s reported everyday food preferences reflect dietary recommendations, and the impact of sociodemographic factors on these associations.Design:&nbsp; Cross-sectional survey.Setting/subjects: Three hundred and seventy-one parents of children aged 2&ndash;5 years, recruited from three socio-economic groups in two Australian cities, completed a survey on their child\u27s liking for 176 foods and drinks on a 5-point Likert scale in addition to demographic descriptors. Preferences were compared with the recommendations of the Dietary Guidelines for Children and Adolescents in Australia and the Australian Guide to Healthy Eating.Results:&nbsp; Foods in the Extra Foods (non-nutritious foods) and Cereals groups of the Australian Guide to Healthy Eating were highly liked (mean: 4.02 and 4.01, respectively), whilst foods in the Vegetables group were liked least (mean: 3.01). A large percentage of foods in the Cereals and Extra Foods groups were liked (64% and 56%, respectively) in contrast to the other food groups, especially Vegetables (7%). Children liked foods that were higher in sugar (r = 0.29, P &lt; 0.0001) and more energy-dense (r = 0.34, P &lt; 0.0001) but not those higher in saturated fat (r = 0.16, P = 0.03), total fat (r = 0.12, P = 0.12) or sodium (r = 0.10, P = 0.18). Sociodemographic variables (e.g. socio-economic status, parental education, children\u27s age and sex) explained little of the variation in children\u27s food preferences.Conclusions:&nbsp; Australian pre-school children\u27s food preferences align with dietary guidelines in some respects, but not others. Interventions are needed to shift children\u27s preferences away from non-nutritious foods that are high in energy density and sugar, and towards vegetables and fruits.<br /

    Itinerarios en la formación inicial para el nivel secundario. Los sentidos de formar docentes en Historia en contextos de ciudadanías de baja intensidad

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    Formar docentes en Historia desde la Universidad implica reconocer el complejo entramado entre el perfil de la formación inicial para el desarrollo del oficio docente y la realidad del contexto escolar donde los profesores en historia se desempeñarán. En este artículo, presentamos el desarrollo de la propuesta de trabajo docente desarrollada por la Cátedra de Didáctica Especial y Práctica Docente de la Facultad de Humanidades de la Universidad Nacional de Mar del Plata (UNMdP), durante diferentes etapas. Presentamos el recorrido y decisiones didácticas que a partir de las tensiones entre formación inicial y escenario escolar nos han interpelado a lo largo de una década. Secuenciamos el itinerario del equipo docente que consciente de la responsabilidad intelectual y política de formar profesores en historia para el nivel secundario, llevó a cabo entre certezas, dudas y descubrimientos. Organizamos la presentación de este itinerario con etapas marcadas por los giros y contrapesos entre el perfil universitario de la formación y el contexto áulico

    Comparison between two treatment protocols with recombinant Human Erythropoietin (rHuEpo) in the treatment of late anemia in neonates with Rh-Isoimmunization

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    Objectve. The Rh-hemolytic disease can lead to a late anemia by hemolytic and hyporigenerative mechanism. We compared the effectiveness of rHuEPO in two care protocols that differ for doses of rHuEPO administrated and for timing of administration. Methods. A cohort of 14 neonates was investigated. The neonates were treated with two different protocols. Protocol A: a dose of 200 U/kg/day of rHuEpo administered subcutaneously starting from the end of the second week of life; Protocol B: a dose of 400 U/kg/day of rHuEpo administered subcutaneously starting from the end of the first week of life. Results. The hematocrit values in the protocol A group decreased during treatment (32,5% vs 25,2%), whereas the hematocrit value in protocol B group remained almost stable (38,7% vs 42,8%). The mean numbers of platelets remained stable in both groups while neutrophils increased in protocol A group and decreased in protocol B (p<0,05). Reticulocyte count increased during treatment in both groups, although only in protocol B group it was statistically significative (p<0,05). Conclusions. Our results suggest a similar efficacy between the two treatment protocols. Increasing doses of rHuEPO do not seem enhancing their effectiveness and the incidence of side effects

    Comparison between two treatment protocols with recombinant Human Erythropoietin (rHuEpo) in the treatment of late anemia in neonates with Rh-Isoimmunization

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    Objectve. The Rh-hemolytic disease can lead to a late anemia by hemolytic and hyporigenerative mechanism. We compared the effectiveness of rHuEPO in two care protocols that differ for doses of rHuEPO administrated and for timing of administration. Methods. A cohort of 14 neonates was investigated. The neonates were treated with two different protocols. Protocol A: a dose of 200 U/kg/day of rHuEpo administered subcutaneously starting from the end of the second week of life; Protocol B: a dose of 400 U/kg/day of rHuEpo administered subcutaneously starting from the end of the first week of life. Results. The hematocrit values in the protocol A group decreased during treatment (32,5% vs 25,2%), whereas the hematocrit value in protocol B group remained almost stable (38,7% vs 42,8%). The mean numbers of platelets remained stable in both groups while neutrophils increased in protocol A group and decreased in protocol B (p<0,05). Reticulocyte count increased during treatment in both groups, although only in protocol B group it was statistically significative (p<0,05). Conclusions. Our results suggest a similar efficacy between the two treatment protocols. Increasing doses of rHuEPO do not seem enhancing their effectiveness and the incidence of side effects
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