Metodologías de Enseñanza y Aprendizaje en la Educación Superior

El siguiente texto aborda las metodologías y estrategias didácticas desde la perspectiva de la enseñanza y el aprendizaje. Entendiendo ambos procesos como multidimensionales, lo que hace necesario precisar lo que se entenderá por enseñanza y aprendizaje en la Educación Superior, revisar características de la relación docente estudiante favorecedoras del aprendizaje y profundizar en los actores del proceso:docentes y estudiantes. Entendiendo las estrategias didácticas como medios para el logro de los aprendizajes que se esperan desarrollar

Étude de l'ensemble de rotation local

In this thesis we are interested in the local dynamics around of a compact invariant sub-manifold and in the rotation number theory. In [Nai82] V.A Naihul' proved that, among analytic or area preserving diffeomorphisms in the plane which are isotopic to the identity fix 0 and whose derivative at 0 is a rotation, the angle of this rotation is invariant by topological conjugation. This result of Naishul' was generalized in many directions (see [GP95], [GLP96] and [Pon12]). For example in [GP95] J.-M. Gambaudo and E. Pécou considered diffeomorphisms in ℝ^{n+2}, which possess an invariant n-dimensional torus T^n whose dynamics restricted to the torus is topologically conjugate to an irrational rotation. They defined a rotation number, and proved that this number is invariant by topological conjugation among volume-preserving maps. In the first part of the second chapter of this thesis, we propose to introduce a notion of local rotation set for local homeomorphisms, which preserve a compact sub-manifold of codimension 2 whose normal bundle is trivial. Using this set, we will deduce a result which generalizes the above mentioned works. In [Rue85] D. Ruelle considered measure preserving diffeomorphisms of a surface whose tangent bundle is trivial. He associated to them a real number called the Ruelle invariant. The constructions made in this thesis will permit us to see this number as a local rotation set over a measure. The invariance by topological conjugation of this set will us permit, at the end of the second chapter, to prove the following result due to J.-M- Gambaudo and E. Ghys: the Ruelle invariant is invariant by topological conjugacy. Let Homeo₀(ℝ²;0) be the set of all homeomorphisms of the plane isotopic to the identity and which fix 0. Recently in [LeR13] F. Le Roux gave the definition of the local rotation set around of 0 of a general isotopy I in Homeo₀(ℝ²;0) from the identity to a homeomorphism f and he asked if this set is always an interval. In the third chapter of this thesis we give a positive answers to this question and to the analogous question in the case of the open annulus.Dans cette thèse nous nous intéressons à la dynamique locale autour d'une sous-variété compacte invariante et à la théorie du nombre de rotation. Dans [Nai82] V. A. Naishul' a montré que parmi les difféomorphismes du plan isotopes à l'identité qui fixent 0, qui préservent l'aire (ou analytiques) et dont la différentielle en 0 est une rotation, l'angle de cette rotation est un invariant de conjugaison topologique. Ce résultat de Naishul', a été généralisé dans plusieurs directions (voir [GP95], [GLP96] et [Pon12]). Par exemple en dimension supérieure, dans [GP95] J.-M. Gambaudo et E. Pécou ont considéré des difféomorphismes de ℝ^{n+2} qui possèdent un tore T^n de dimension n invariant dont la dynamique est topologiquement conjuguée à une rotation irrationnelle. Ils ont défini un nombre de rotation et ont démontré que ce nombre est invariant de conjugaison topologique (par exemple lorsque le difféomorphisme préserve un volume). Dans la première partie du deuxième chapitre de cette thèse, nous proposons d'introduire une notion d'ensemble de rotation local pour les homéomorphismes locaux qui préservent une sous-variété compacte de codimension 2 dont le fibré normal est trivial. A l'aide de cet ensemble, nous déduirons un résultat qui généralise les travaux en dimension supérieure cités plus haut. Dans [Rue85] D. Ruelle a considéré des difféomorphismes d'une surface dont le fibré tangent est trivial qui préservent une mesure. Il leur a associé un nombre réel qui a été appelé l'invariant de Ruelle. Les constructions de cette thèse nous permettront de voir cet invariant comme un ensemble de rotation local au-dessus d'une mesure. A l'aide de l'invariance par conjugaison de cet ensemble de rotation, nous allons retrouver, à la fin du deuxième chapitre, le résultat démontré par J.-M. Gambaudo et E. Ghys dans [GG97] : l'invariant de Ruelle est en fait invariant de conjugaison topologique. Soit Homeo₀(ℝ²;0) l'ensemble des homéomorphismes du plan ℝ² isotopes a l'identité qui fixent l'origine 0∈ℝ². Récemment dans [LeR13], F. Le Roux a donné une définition de l'ensemble de rotation local autour de d'une isotopie dans Homeo₀(ℝ²;0) issue de l'identité, et il a posé la question suivante : cet ensemble est-il toujours un intervalle ? Dans le troisième chapitre de cette thèse, nous allons donner une réponse positive à cette question et aussi à la question analogue dans le cas de l'anneau ouvert

Eficacia de un estimulante versus un sustituto salival en el tratamiento de la xerostomía y su impacto en la calidad de vida

Tesis (Cirujano Dentista)Introducción: La xerostomía o síndrome de boca seca, es la sensación subjetiva de sequedad bucal, que puede o no estar relacionada a la disminución de la saliva, o a cambios en la composición química de ésta (12, 13, 14, 20).La prevalencia de xerostomía oscila entre 17-29% (13), afectando en mayor medida a mujeres menopáusicas e individuos sobre los 65 años. Existen múltiples causas como el uso de fármacos xerogénicos, radioterapia de cabeza y cuello, enfermedades autoinmunes o trastornos psicológicos. La Xerostomía puede provocar múltiples alteraciones físicas, psicológicas y psicosociales, teniendo un fuerte impacto en la calidad de vida de los pacientes (28). Existe una gran variabilidad de terapias para el tratamiento de la xerostomía. Actualmente en el comercio chileno existen sólo dos agentes disponibles, sin embargo, no existen protocolos claramente establecidos, ni evidencia que avale que un tratamiento sea mejor que otro. Comprender cuál presenta mayor eficacia en una patología con múltiples etiologías como ésta, puede guiar a los especialistas a elegir la mejor terapia para sus pacientes. Materiales y Métodos: Este corresponde a un ensayo clínico controlado, doble ciego, randomizado. Se seleccionó una muestra de 51 pacientes con xerostomía que fueron divididos en tres grupos. Para el primer grupo –grupo intervención: 17 sujetos-, se aplicó un spray de ácido málico al 1%. Para el segundo grupo –grupo placebo: 17 sujetos-, se aplicó un spray placebo (xilitol al 10%, fluoruro de sodio al 0,05%. Para el tercer grupo –grupo intervención: 17 sujetos-, se aplicó un colutorio de Betaína al 1,33%, y Alantoína al 0,10%. Para los tres grupos el medicamento fue aplicado según necesidad durante dos semanas y registrado por el paciente en un diario de aplicación. Se analizaron distintas variables como el cuestionario OHIP-14 para evaluar la percepción oral de calidad de vida, la escala visual análoga –EVA- para evaluar la percepción subjetiva de sequedad oral, el test de sialometría estimulada y no estimulada, entre otras. Resultados: Se realizó una base de datos en Microsoft Excel 2007 y estos se analizaron en el programa estadístico SPSS. En relación a las variables edad y género, no se presentaron diferencias significativas, pero se observó que los rangos de edades fueron entre 56 y 65, con mayor frecuencia en mujeres. En relación a la variable flujo salival no estimulados y sensación subjetiva de boca seca (EVA) se presentó diferencia significativa post-tratamiento tanto en los grupos de intervención como en el control. En relación a la calidad de vida, mediante el registro con encuesta OHIP-14, sólo la dimensión “incapacidad psicológica” en el grupo placebo presento diferencia significativa. Al analizar el puntaje total se observan diferencias significativas pre y post-tratamiento en ambos grupos de intervención, spray y colutorio, no así en el grupo placebo. Conclusiones: La presencia de xerostomía es más común en mujeres entre la 5° y 6° década de vida. Tanto los agentes activos como el placebo fueron efectivos en reducir la percepción subjetiva de xerostomía, aumentaron el flujo salival no estimulado, percibieron en mayor proporción como “Efectivo” los tratamientos para la xerostomía y presentaron una “adherencia” similar al tratamiento. El Spray ácido málico y el Colutorio tuvieron un impacto positivo en la calidad de vida de los pacientes. El Spray ácido málico fue más utilizado diariamente

Using Major Histocompatibility Genes Polymorphism to Identify Arctic Charr (Salvelinus alpinus) Populations

Arctic charr is the most northerly distributed salmonid and the most abundant fish in high latitude postglacial lakes. Arctic charr lives in oligotrophic water bodies where it has been able to adapt and thrive due, in part, its noted outstanding phenotypic plasticity. Throughout its geographic range, the Arctic charr has had to specialize to get the most of each ecosystem, to the point that Arctic charr were originally described as 56 different species and only later considered as many phenotypic variations of the same group, called the Arctic charr complex. With the aim of using the resources available in areas with very low primary production, Arctic charr often specialize to become different morphotypes within the same water body. Each morphotype can follow different life histories that can be anadromous or non-migratory. In several lakes, the non-migratory stocks may also differentiate further, each form with its own trophic and/or reproductive behavior. Adult sympatric forms may differ in depth distribution, size-at-maturity, time and place of spawning, color and/or other meristic characters that include differential gill raker and vertebrae numbers. The two typical forms that are found in sympatry are a small, profoundal form often termed “dwarf” Arctic charr and a large, littoral or pelagic zone resident often termed “Normal” Arctic charr. The Arctic charr colonized most of its current habitat very recently, after the ice retreat in the late Pleistocene, 10000-15000 years ago. The reproductive isolation of stocks, if it has occurred at all, occurred so recently that the accumulated genetic drift often does not yield enough data to support the genetic separation of the stocks. Since the geographic borders of the stocks tend to be unclear and because the Arctic charr is a migratory species, the management of fisheries can be difficult in light of these issues, this thesis examines the potential for identifying Arctic charr populations using Major Histocompatibility (MH) genes as molecular markers. MH genes are useful because they are not neutral markers, but are subject to selection. MH receptors present peptides to T-lymphocytes and from that interaction the immune system defines what is self or non-self and thus whether or not immune reactions should be initiated. Due to the large variety of potential pathogenic peptides to be presented, the domain of the MH receptor that binds the peptide, the peptide binding region, is the most polymorphic coding region known. Each individual has a limited number of MH alleles. Given the high degree of polymorphism in populations it is virtually impossible that two individuals will share the same set, of MHC alleles with the exception of monozygotic twins. Since MH receptors present peptides derived from pathogens, they are related to disease resistance, and some MH alleles are more effective at presenting certain peptides than others. Therefore, populations settled in a specific niche will interact with a defined variety of pathogens that will select for certain patterns in the MH alleles of the population. The selection of these MH allelic patterns occurs rapidly, since they determine the survival of the individuals during disease outbreaks. Rapid selection means that MH allelic patterns they can be used to differentiate populations that have been separated for relatively short periods of time. The MH genes of Arctic charr had not been characterized before the publication of this thesis, so the first step was their isolation and characterization. We found the MH sequences obtained to have typical characteristics of classical MH receptors, sharing similarities with other salmonids and having most of their variation in the peptide binding region. We next characterized populations of Arctic charr selected from the global distribution using the three polymorphic MH receptors. For all of the receptor we found most of the polymorphisms distributed equally amongst the populations, but the interpopulation diversity was generally enough to differentiate at least some of the studied populations. For the MH Class I we studied three non classical (UCA, UGA, UEA) and one classical (UBA) gene. For UBA and UCA we found a large degree of polymorphism while UGA and UEA were not very polymorphic. Despite the fact that the UGA gene was also not polymorphic in studies of rainbow trout, we found the gene to be the best Class I population marker for Arctic charr because it had the highest relative rates of interpopulation diversity. Thus, UGA may be exhibiting some antigen presentation functions in Arctic charr. The population analysis using MH Class II α and Class II β genes were the most successful. Particularly in the case of Class II β, the analyses arose capable of differentiating all the populations chosen for this study. Both genes showed high levels of polymorphism and high rates of non-synonymous/synonymous substitution in the exon that encodes the peptide binding region. Lastly, we used MHC Class II α and Class II β to differentiate two separate sets of morphotypes living in sympatry in Lake Kiryalta in Russia and Gander Lake in Canada. The morphotypes in Gander Lake were successfully differentiated using both MH Class II α and β allele data, while the morphotypes in Lake Kiryalta were separated only with the MH Class II β allele data. Given that the use of one or more MH genes used allowed us to differentiate the populations studied, MH genes seem to be extremely useful as population markers for Arctic charr. Since MH genes not only characterize populations according to their phylogenetic relationships, but also according to their specific adaptation to inhabited niches, we concluded that all the Arctic charr populations studied are independent evolutionary significant units of the Arctic charr species. The conclusion implies that although different stocks might be living in sympatry, they should be considered as separate species for fishery and other management purposes, because their specific adaptations to the pathogens in their ecological niche might not allow them to cross-repopulate the other stock if it were removed by over-fishing or other anthropogenic stresses

Simulation and optimization of dynamic flux balance analysis models using an interior point method reformulation

This work presents a novel, differentiable, way of solving dynamic Flux Balance Analysis (dFBA) problems by embedding flux balance analysis of metabolic network models within lumped bulk kinetics for biochemical processes. The proposed methodology utilizes transformation of the bounds of the embedded linear programming problem of flux balance analysis via a logarithmic barrier (interior point) approach. By exploiting the first-order optimality conditions of the interior-point problem, and with further transformations, the approach results in a system of implicit ordinary differential equations. Results from four case studies, show that the CPU and wall-times obtained using the proposed method are competitive with existing state-of-the-art approaches for solving dFBA simulations, for problem sizes up to genome-scale. The differentiability of the proposed approach allows, using existing commercial packages, its application to the optimal control of dFBA problems at a genome-scale size, thus outperforming existing formulations as shown by two dynamic optimization case studies.• R. Conejeros would like to thank CONICYT’s research grant FONDECYT 1151295 for funding this research. • F. Scott gratefully acknowledges financial support from CONICYT (Proyectos REDES ETAPA INICIAL, Convocatoria 2017, REDI170254)