Neutrino mixing and masses in a left-right model with mirror fermions

In the framework of a left-right model containing mirror fermions with gauge group SU(3)$_{C} \otimes SU(2)_{L} \otimes SU(2)_{R} \otimes U(1)_{Y^\prime}$, we estimate the neutrino masses, which are found to be consistent with their experimental bounds and hierarchy. We evaluate the decay rates of the Lepton Flavor Violation (LFV) processes $\mu \rightarrow e \gamma$, $\tau \rightarrow \mu \gamma$ and $\tau \rightarrow e\gamma$. We obtain upper limits for the flavor-changing branching ratios in agreement with their present experimental bounds. We also estimate the decay rates of heavy Majorana neutrinos in the channels $N \rightarrow W^{\pm} l^{\mp}$, $N \rightarrow Z \nu_{l}$ and $N \rightarrow H \nu_{l}$, which are roughly equal for large values of the heavy neutrino mass. Starting from the most general Majorana neutrino mass matrix, the smallness of active neutrino masses turns out from the interplay of the hierarchy of the involved scales and the double application of seesaw mechanism. An appropriate parameterization on the structure of the neutrino mass matrix imposing a symmetric mixing of electron neutrino with muon and tau neutrinos leads to Tri-bimaximal mixing matrix for light neutrinos.Comment: Accepted by European Physical Journal

Arginine-rich peptides destabilize the plasma membrane, consistent with a pore formation translocation mechanism of cell penetrating peptides

Recent molecular dynamics simulations (Herce and Garcia, PNAS, 104: 20805 (2007)) have suggested that the arginine-rich HIV Tat peptides might be able to translocate by destabilizing and inducing transient pores in phospholipid bilayers. In this pathway for peptide translocation, arginine residues play a fundamental role not only in the binding of the peptide to the surface of the membrane but also in the destabilization and nucleation of transient pores across the bilayer, despite being charged and highly hydrophilic. Here we present a molecular dynamics simulation of a peptide composed of nine arginines (Arg-9) that shows that this peptide follows the same translocation pathway previously found for the Tat peptide. We test this hypothesis experimentally by measuring ionic currents across phospholipid bilayers and cell membranes through the pores induced by Arg-9 peptides. We find that Arg-9 peptides, in the presence of an electrostatic potential gradient, induce ionic currents across planar phospholipid bilayers, as well as in cultured osteosarcoma cells and human smooth muscle cells freshly isolated from the umbilical artery. Our results suggest that the mechanism of action of Arg-9 peptide involves the creation of transient pores in lipid bilayers and cell membranes.Comment: This is an extended version of the published manuscript, which had to be shortened before publication to fit within the number of pages required by the journa

Maximal Commutative Subalgebras Invariant for CP-Maps: (Counter-)Examples

We solve, mainly by counterexamples, many natural questions regarding maximal commutative subalgebras invariant under CP-maps or semigroups of CP-maps on a von Neumann algebra. In particular, we discuss the structure of the generators of norm continuous semigroups on B(G) leaving a maximal commutative subalgebra invariant and show that there exists Markov CP-semigroups on M_d without invariant maximal commutative subalgebras for any d>2.Comment: After the elemenitation in Version 2 of a false class of examples in Version 1, we now provide also correct examples for unital CP-maps and Markov semigroups on M_d for d>2 without invariant masa

Estructura del mercado de créditos y tasas de interés: una aproximación al segmento de las microfinanzas

A través de un modelo microfundado, los autores analizan la estructura del mercado de créditos en dos de sus segmentos: corporativo y microfinanzas. Haciendo uso de un modelo de datos de panel para el período 1998-I a 2002-II, se concluye que las entidades que operan en el segmento de microfinanzas gozan de cierto poder de mercado para influir sobre sus tasas de interés. Este poder es originado posiblemente por la utilización de una tecnología de crédito distinta a la convencional, la cual permite acotar el riesgo de crédito producido por el problema de asimetría de información (que se muestra de una manera más acentuada en este segmento). La carencia de esta tecnología por parte de potenciales competidores estaría dificultando su entrada al segmento. Por el contrario, el segmento corporativo se aproxima más a una estructura competitiva, pues las imperfecciones en materia de información son menores y los prestatarios que en él participan cuentan con mayores alternativas de financiamiento.

Early alterations in vascular contractility associated to changes in fatty acid composition and oxidative stress markers in perivascular adipose tissue

<p>Abstract</p> <p>Aim</p> <p>To test the early effect of fructose-induced changes in fatty acid composition and oxidative stress markers in perivascular adipose tissue (PVAT) upon vascular contractility.</p> <p>Methods</p> <p>Adult male Wistar rats were fed a commercial diet without (CD) or with 10% fructose (FRD) in the drinking water for 3 weeks. We measured plasma metabolic parameters, lipid composition and oxidative stress markers in aortic PVAT. Vascular contractility was measured in aortic rings sequentially, stimulated with serotonin (5-HT) and high K⁺-induced depolarization using intact and thereafter PVAT-deprived rings.</p> <p>Results</p> <p>Comparable body weights were recorded in both groups. FRD rats had increased plasma triglyceride and fructosamine levels. Their PVAT had an increased saturated to mono- or poly-unsaturated fatty acid ratio, a significant decrease in total superoxide dismutase and glutathione peroxidase activities and in the total content of glutathione. Conversely, lipid peroxidation (TBARS), nitric oxide content, and gluthathione reductase activity were significantly higher, indicating an increase in oxidative stress. In aortic rings, removal of PVAT increased serotonin-induced contractions, but the effect was significantly lower in rings from FRD rats. This effect was no longer observed when the two contractions were performed in PVAT-deprived rings. PVAT did not affect the contractions triggered by high K⁺-induced depolarization either in CD or FRD rats.</p> <p>Conclusions</p> <p>FRD induces multiple metabolic and endocrine systemic alterations which also alter PVAT and the vascular relaxant properties of this tissue. The changes in PVAT would affect its paracrine modulation of vascular function.</p

InContext: A mobile application for the improvement of learning strategies at University // InContext: Una aplicación móvil para mejorar las estrategias de aprendizaje en la Universidad

InContext is a custom-designed mobile application for writing assignments intended for university students in journalism and research methodology courses. In these disciplines, it has been observed that there is a need for an educational and technological tool to guide the writing of text using preloaded templates in which students can input text and multimedia material to create articles or write research reports. Besides its ease of use, the app was intended to improve metacognitive thinking. This led to the establishment of six working hypotheses in an exploratory study. For the study, a random sample of students enrolled in the aforementioned courses was selected during the August-December 2019 semester at a private university in Mexico. They took a pre-test using the “Motivated Strategies for Learning Questionnaire” (MSLQ) that had been translated into Spanish and already validated in Mexico. Subsequently, the students used the application and then answered the same questionnaire as a post-test. The study aimed to compare the results of the tests to see whether there was an improvement in cognitive skills. The results showed an increase in four skills: critical thinking, data search, cognitive self-regulation, and regulation of effort. The research results did indicate metacognitive development that would benefit the academic and professional work of future graduates

InContext: A mobile application for the improvement of learning strategies at University

InContext es una aplicación móvil, diseñada a medida, para elaborar trabajos de redacción para estudiantes universitarios de los cursos de periodismo y de metodología de la investigación. En estas disciplinas se observó que había una necesidad de contar con una herramienta educativa y tecnológica que guiara la redacción utilizando plantillas precargadas en las cuales los estudiantes pudieran agregar texto y material multimedia para con ello construir artículos periodísticos o reportes de investigación. Además de la facilidad de uso, se esperaba que la app mejorara el pensamiento metacognitivo, por lo cual se establecieron seis hipótesis de trabajo en un estudio exploratorio. Para la investigación se seleccionó una muestra aleatoria de estudiantes inscritos en los cursos durante el semestre agosto-diciembre 2019 en una universidad privada de México. Los alumnos realizaron un pretest utilizando el cuestionario Motivated Strategies for Learning Questionnaire (MSLQ) traducido al español y ya validado en México; posteriormente utilizaron la aplicación y contestaron el mismo cuestionario a manera de postest, con el objetivo de comparar si había una mejora en las habilidades cognitivas. Los resultados indican que existe un aumento en cuatro habilidades: pensamiento crítico, búsqueda de datos, autorregulación cognitiva y regulación del esfuerzo, pero no lo hubo en organización ni en búsqueda de ayuda. Estos resultados indican un desarrollo metacognitivo que beneficia el trabajo académico y profesional de los futuros egresadosInContext is a custom-designed mobile application for writing assignments intended for university students in journalism and research methodology courses. In these disciplines, it has been observed that there is a need for an educational and technological tool to guide the writing of text using preloaded templates in which students can input text and multimedia material to create articles or write research reports. Besides its ease of use, the app was intended to improve metacognitive thinking. This led to the establishment of six working hypotheses in an exploratory study. For the study, a random sample of students enrolled in the aforementioned courses was selected during the August-December 2019 semester at a private university in Mexico. They took a pre-test using the “Motivated Strategies for Learning Questionnaire” (MSLQ) that had been translated into Spanish and already validated in Mexico. Subsequently, the students used the application and then answered the same questionnaire as a post-test. The study aimed to compare the results of the tests to see whether there was an improvement in cognitive skills. The results showed an increase in four skills: critical thinking, data search, cognitive self-regulation, and regulation of effort. The research results did indicate metacognitive development that would benefit the academic and professional work of future graduate

InContext: A mobile application for the improvement of learning strategies at University // InContext: Una aplicación móvil para mejorar las estrategias de aprendizaje en la Universidad

InContext is a custom-designed mobile application for writing assignments intended for university students in journalism and research methodology courses. In these disciplines, it has been observed that there is a need for an educational and technological tool to guide the writing of text using preloaded templates in which students can input text and multimedia material to create articles or write research reports. Besides its ease of use, the app was intended to improve metacognitive thinking. This led to the establishment of six working hypotheses in an exploratory study. For the study, a random sample of students enrolled in the aforementioned courses was selected during the August-December 2019 semester at a private university in Mexico. They took a pre-test using the “Motivated Strategies for Learning Questionnaire” (MSLQ) that had been translated into Spanish and already validated in Mexico. Subsequently, the students used the application and then answered the same questionnaire as a post-test. The study aimed to compare the results of the tests to see whether there was an improvement in cognitive skills. The results showed an increase in four skills: critical thinking, data search, cognitive self-regulation, and regulation of effort. The research results did indicate metacognitive development that would benefit the academic and professional work of future graduates