Double products and hypersymplectic structures on R4nR^{4n}

In this paper we give a procedure to construct hypersymplectic structures on $R^{4n}$ beginning with affine-symplectic data on $R^{2n}$. These structures are shown to be invariant by a 3-step nilpotent double Lie group and the resulting metrics are complete and not necessarily flat. Explicit examples of this construction are exhibited

Quaternion Kahler flat manifolds

It is the main purpose of this lecture to indicate a rather general method to construct quaternion-Kahler compact flat manifolds. This construction will give many families of quaternion Kahler manifolds of dimensions 8 or greater, which admit no Kahler structure  (see Section 3). This will follow from the  explicit calculation of the Betti numbers of the manifolds involved.Fil: Dotti, Isabel Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Estudios de Matemática. Universidad Nacional de Córdoba. Centro de Investigación y Estudios de Matemática; ArgentinaFil: Miatello, Roberto Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Estudios de Matemática. Universidad Nacional de Córdoba. Centro de Investigación y Estudios de Matemática; Argentin

Abelian Hermitian geometry

We study the structure of Lie groups admitting left invariant abelian complex structures in terms of commutative associative algebras. If, in addition, the Lie group is equipped with a left invariant Hermitian structure, it turns out that such a Hermitian structure is K\"ahler if and only if the Lie group is the direct product of several copies of the real hyperbolic plane by a euclidean factor. Moreover, we show that if a left invariant Hermitian metric on a Lie group with an abelian complex structure has flat first canonical connection, then the Lie group is abelian.Comment: 14 page

Algoritmo de Euclides y algunas aplicaciones

El objetivo de este trabajo es presentar el algoritmo de división en los enteros y algunas aplicaciones que ilustren su importancia y belleza. Debido a que estamos plenamente convencidas, de que la mejor manera de estimular y lograr el aprendizaje de la matemática es a través de planteos y soluciones de problemas, dedicamos gran parte de estas notas a la presentación y solución de algunos de ellos. Si bien no contamos con suficiente experiencia docente primaria y secundaria, creemos que los resultados y ejemplos que aparecen son facilmente adaptables para ser accesibles e interesantes a los alumnos

Hyperk\"ahler torsion structures invariant by nilpotent Lie groups

We study HKT structures on nilpotent Lie groups and on associated nilmanifolds. We exhibit three weak HKT structures on $\R^8$ which are homogeneous with respect to extensions of Heisenberg type Lie groups. The corresponding hypercomplex structures are of a special kind, called abelian. We prove that on any 2-step nilpotent Lie group all invariant HKT structures arise from abelian hypercomplex structures. Furthermore, we use a correspondence between abelian hypercomplex structures and subspaces of ${\frak sp}(n)$ to produce continuous families of compact and noncompact of manifolds carrying non isometric HKT structures. Finally, geometrical properties of invariant HKT structures on 2-step nilpotent Lie groups are obtained.Comment: LateX, 12 page

Constitutive hippocampal cholesterol loss underlies poor cognition in old rodents

Cognitive decline is one of the many characteristics of aging. Reduced long-term potentiation (LTP) and long-term depression (LTD) are thought to be responsible for this decline, although the precise mechanisms underlying LTP and LTD dampening in the old remain unclear. We previously showed that aging is accompanied by the loss of cholesterol from the hippocampus, which leads to PI3K/Akt phosphorylation. Given that Akt de-phosphorylation is required for glutamate receptor internalization and LTD, we hypothesized that the decrease in cholesterol in neuronal membranes may contribute to the deficits in LTD typical of aging. Here, we show that cholesterol loss triggers p-Akt accumulation, which in turn perturbs the normal cellular and molecular responses induced by LTD, such as impaired AMPA receptor internalization and its reduced lateral diffusion. Electrophysiology recordings in brain slices of old mice and in anesthetized elderly rats demonstrate that the reduced hippocampal LTD associated with age can be rescued by cholesterol perfusion. Accordingly, cholesterol replenishment in aging animals improves hippocampal-dependent learning and memory in the water maze test.publishedVersionFil: Martín, Mauricio Gerardo. Consejo Superior de Investigaciones Científicas. Centro de Biología Molecular Severo Ochoa; España.Fil: Martín, Mauricio Gerardo. Universidad Autónoma de Madrid. Centro de Biología Molecular Severo Ochoa; España.Fil: Martín, Mauricio Gerardo. Katholieke Universiteit Leuven. Center for Human Genetics. VIB Center for the Biology of Disease; Bélgica.Fil: Ahmed, Tariq. Katholieke Universiteit Leuven. Faculty of Psychology and Educational Sciences. Laboratory of Biological Psychology; Bélgica.Fil: Korovaichuk, Alejandra. Consejo Superior de Investigaciones Científicas. Instituto Cajal. Departamento de Neurobiología Funcional y de Sistemas; España.Fil: Venero, César. Universidad Nacional de Educación a Distancia. Facultad de Psicología. Departamento de Psicobiología; España.Fil: Menchón, Silvia Adriana. Katholieke Universiteit Leuven. Center for Human Genetics. VIB Center for the Biology of Disease; Bélgica.Fil: Menchón, Silvia Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Menchón, Silvia Adriana. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Salas, Isabel. Consejo Superior de Investigaciones Científicas. Centro de Biología Molecular Severo Ochoa; España.Fil: Salas, Isabel. Universidad Autónoma de Madrid. Centro de Biología Molecular Severo Ochoa; España.Fil: Salas, Isabel. Consejo Superior de Investigaciones Científicas. Centro de Biología Molecular Severo Ochoa; España.Fil: Munck, Sebastian. Katholieke Universiteit Leuven. Center for Human Genetics. VIB Center for the Biology of Disease; Bélgica.Fil: Herreras, Oscar. Consejo Superior de Investigaciones Científicas. Instituto Cajal. Departamento de Neurobiología Funcional y de Sistemas; España.Fil: Balschun, Detlef. Katholieke Universiteit Leuven. Faculty of Psychology and Educational Sciences. Laboratory of Biological Psychology; Bélgica.Fil: Dotti, Carlos Gerardo. Consejo Superior de Investigaciones Científicas. Centro de Biología Molecular Severo Ochoa; España.Fil: Dotti, Carlos Gerardo. Universidad Autónoma de Madrid. Centro de Biología Molecular Severo Ochoa; España.Fil: Dotti, Carlos Gerardo. Katholieke Universiteit Leuven. Center for Human Genetics. VIB Center for the Biology of Disease; Bélgica.Biofísic

Allogeneic haematopoietic stem cell transplantation for mitochondrial neurogastrointestinal encephalomyopathy

Mitochondrial neurogastrointestinal encephalopathy (MNGIE) is a rare fatal autorecessive disease. Halter et al. report outcomes from all known haematopoietic stem cell transplantations worldwide from sibling or unrelated donors for MNGIE between 2005 and 2011. In some of the recipients, correction of the underlying metabolic defect results in gradual clinical improvemen

Aging and Brain Deterioration

Carlos Dotti and Vicente Rodríguez (coordinators).Advanced age significantly increases the risk of developing chronic diseases such as cancer, diabetes, cardiovascular, immune and mental disease. Regarding the latter, advanced age is a necessary factor for the development of non-hereditary forms of neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Despite years of intense research, we still do not know how these diseases occur, this being one of the main reasons for the lack of adequate interventions to prevent or cure these pathologies. To overcome the current limitations in the field, we plan to: 1) generate basic knowledge on the mechanisms responsible for cognitive, behavioral, motor, metabolic and sociability disorders that occur with age, 2) define the mechanisms that determine individual susceptibility to neurodegeneration, 3) design and develop strategies to improve brain aging, and 4) explore social and environmental conditions of the older population to know their influence in brain degeneration. Individual, social and policy interventions must be considered for future research.Peer reviewe