Generalized Hantzsche-Wendt Flat Manifolds

We study the family of closed Riemannian n-manifolds with holonomy group isomorphic to $Z_2^{n-1}$, which we call generalized Hantzsche-Wendt manifolds. We prove results on their structures, compute some invariants, and find relations between them, illustrated in graph connecting the family.Comment: 16 pages, 1 figure. Revista Matematica Iberoamericana. Vol. 21, no. 3 (2005). (to appear

Strongly isospectral manifolds with nonisomorphic cohomology rings

For any $n\geq 7$, $k\geq 3$, we give pairs of compact flat $n$-manifolds $M, M'$ with holonomy groups $\mathbb Z_2^k$, that are strongly isospectral, hence isospectral on $p$-forms for all values of $p$, having nonisomorphic cohomology rings. Moreover, if $n$ is even, $M$ is K\"ahler while $M'$ is not. Furthermore, with the help of a computer program we show the existence of large Sunada isospectral families; for instance, for $n=24$ and $k=3$ there is a family of eight compact flat manifolds (four of them K\"ahler) having very different cohomology rings. In particular, the cardinalities of the sets of primitive forms are different for all manifolds.Comment: 25 pages, to appear in Revista Matem\'atica Iberoamerican

Spectra of lens spaces from 1-norm spectra of congruence lattices

To every $n$-dimensional lens space $L$, we associate a congruence lattice $\mathcal L$ in $\mathbb Z^m$, with $n=2m-1$ and we prove a formula relating the multiplicities of Hodge-Laplace eigenvalues on $L$ with the number of lattice elements of a given $\|\cdot\|_1$-length in $\mathcal L$. As a consequence, we show that two lens spaces are isospectral on functions (resp.\ isospectral on $p$-forms for every $p$) if and only if the associated congruence lattices are $\|\cdot\|_1$-isospectral (resp.\ $\|\cdot\|_1$-isospectral plus a geometric condition). Using this fact, we give, for every dimension $n\ge 5$, infinitely many examples of Riemannian manifolds that are isospectral on every level $p$ and are not strongly isospectral.Comment: Accepted for publication in IMR

Non-strongly isospectral spherical space forms

In this paper we describe recent results on explicit construction of lens spaces that are not strongly isospectral, yet they are isospectral on $p$-forms for every $p$. Such examples cannot be obtained by the Sunada method. We also discuss related results, emphasizing on significant classical work of Ikeda on isospectral lens spaces, via a thorough study of the associated generating functions

Utilización de altas dosis de ácido ascórbico en el tratamiento del SARS Covid-19: Soporte Científico y Clínico para su aplicación en terapéutica

The 2019 coronavirus (SARS-CoV-2) has been declared a public health emergency of international concern by the World Health Organization. Due to the sudden appearance of this pandemic process associated with increasing morbidity and mortality worldwide, various treatments have been implemented. In this framework, high doses of vitamin C began to be used in critically ill patients. We analyze the clinical trials and/or research papers available in the literature. Although more evidence on its effectiveness is needed is important for the specialist to understand the clinical logic of this use to determine if it is correct as a concomitant treatment. Conclusions: It seems that using high doses of vitamin C parenterally is a safe, available and economical alternative especially for critically ill patients.El coronavirus 2019 (SARS-CoV-2) ha sido declarado una emergencia de salud pública de impacto internacional por la Organización Mundial de la Salud. Debido a la aparición repentina de este proceso pandémico asociado con alta morbilidad y la mortalidad en todo el mundo, se han implementado varios tratamientos en los pacientes aquejados con esta dolencia. En este marco, comenzaron a usarse en pacientes críticos altas dosis de vitamina C. En este trabajo, analizamos los ensayos clínicos y / o trabajos de investigación disponibles en la literatura. Aunque se necesita más evidencia sobre su efectividad, es importante que el especialista comprenda la lógica clínica de este uso para determinar si es correcto como tratamiento concomitante. Conclusiones: El uso de altas dosis de vitamina C por vía parenteral parece ser una alternativa segura, disponible y económica, especialmente para pacientes críticos.publishedVersionFil: Rossetti, Cristian Alan. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Rossetti, Cristian Alan. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica; Argentina.Fil: Real, Juan Pablo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Real, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica; Argentina.Fil: Palma, Santiago Daniel. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Palma, Santiago Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica; Argentina