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

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.

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

Cis-regulatory elements are harbored in Intron5 of the RUNX1 gene

BACKGROUND: Human RUNX1 gene is one of the most frequent target for chromosomal translocations associated with acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL). The highest prevalence in AML is noted with (8; 21) translocation; which represents 12 to 15% of all AML cases. Interestingly, all the breakpoints mapped to date in t(8;21) are clustered in intron 5 of the RUNX1 gene and intron 1 of the ETO gene. No homologous sequences have been found at the recombination regions; but DNase I hypersensitive sites (DHS) have been mapped to the areas of the genes involved in t(8;21). Presence of DHS sites is commonly associated with regulatory elements such as promoters, enhancers and silencers, among others. RESULTS: In this study we used a combination of comparative genomics, cloning and transfection assays to evaluate potential regulatory elements located in intron 5 of the RUNX1 gene. Our genomic analysis identified nine conserved non-coding sequences that are evolutionarily conserved among rat, mouse and human. We cloned two of these regions in pGL-3 Promoter plasmid in order to analyze their transcriptional regulatory activity. Our results demonstrate that the identified regions can indeed regulate transcription of a reporter gene in a distance and position independent manner; moreover, their transcriptional effect is cell type specific. CONCLUSIONS: We have identified nine conserved non coding sequence that are harbored in intron 5 of the RUNX1 gene. We have also demonstrated that two of these regions can regulate transcriptional activity in vitro. Taken together our results suggest that intron 5 of the RUNX1 gene contains multiple potential cis-regulatory elements

Using rhythmic nonces for puzzle-based DoS resistance

To protect against replay attacks, many Internet proto-cols rely on nonces to guarantee freshness. In practice, the server generates these nonces during the initial hand-shake, but if the server is under attack, resources con-sumed by managing certain protocols can lead to DoS vulnerabilities. To help alleviate this problem, we pro-pose the concept of rhythmic nonces, a cryptographic tool that allows servers to measure request freshness with minimal bookkeeping costs. We explore the impact of this service in the context of a puzzle-based DoS re-sistance scheme we call “SYN puzzles”. Our preliminary results based on mathematical analysis and evaluation of a prototype suggests that our scheme is more resistant than existing techniques. 1