Effect of Vitrification on Epigenetic Modifications and the Meiotic Spindle of Bovine Oocytes

While oocyte vitrification has become a common practice, it still faces some challenges such as the low survival rates after warming, probably related to cryoinjuries and cryoprotectant (CPA) toxicity. Evidence suggests that vitrification might have an effect on the patterns of some epigenetic marks including DNA methylation and histone acetylation. During fertilization and embryogenesis, key events for healthy and adequate embryo development take place, not only governed by the information contained within the DNA sequence, but also by epigenetic mechanisms. This study was aimed at determining the effect of vitrification and CPA exposure, using a combination of ethylene glycol (EG) with either DMSO or glycerol (Gly), on DNA methylation and histone acetylation of bovine oocytes. Additionally, the effect of vitrification and cryoprotective solutions on the meiotic spindle was evaluated. To achieve this goal, three experiments were carried out. The first experiment was intended to evaluate the effect of vitrification on DNA methylation of bovine cumulus-oocyte complexes (COCs) at two different maturation stages, germinal vesicle (GV) and metaphase II (MII). The second was designed to determine the effect of CPA exposure on DNA methylation and histone acetylation. The last experiment assessed the impact of vitrification and CPA exposure on microtubule distribution and chromosome arrangement, and if a subsequent incubation period after vitrification could promote the reorganization of the spindle. Results obtained suggest that vitrification of bovine oocytes at the GV stage does not have an effect on DNA methylation patterns. Similar outcomes were obtained when comparing oocytes in the MII vitrified with DMSO and fresh oocytes. However, oocytes vitrified with Gly showed an abnormality presented in the form of DNA fragmentation. On the other hand, exposure to EG + DMSO increases the levels of DNA methylations in comparison with fresh oocytes. CPA exposure does not have an effect on histone acetylation levels. Finally, results of the third experiment indicate that CPA exposure has no impact on the incidence of abnormal meiotic spindles. In contrast, vitrification using DMSO increases the occurrence of abnormal meiotic spindles and the damage seems to be irreversible. The incubation period following vitrification with EG + Gly promotes the reorganization of microtubules

Fighting Crime with a Little Help from my Friends: Party Affiliation, Inter‐jurisdictional Cooperation and Crime in Mexico

We investigate the relationship between inter-jurisdictional cooperation and law enforcement in Mexico. Exploiting a Regression Discontinuity Design in close municipal elections, we study how improved opportunities for cooperation in crime prevention among neighboring municipalities - proxied by their degree of political alignment - may result in lower rates of violent crime. We find that municipalities in which the party in power in the majority of neighboring jurisdictions barely won experience significantly lower homicide rates during the mayor’s mandate than those in which it barely lost. This effect is sizeable and independent of which party is in power in the neighboring municipalities

A value for cooperative games with a coalition structure

A value for games with a coalition structure is introduced, where the rules guiding the cooperation among the members of the same coalition are different from the interaction rules among coalitions. In particular, players inside a coalition exhibit a greater degree of solidarity than they are willing to use with players outside their coalition. The Shapley value [Shapley, 1953] is therefore used to compute the aggregate payoffs of the coalitions, and the Solidarity value [Nowak and Radzik, 1994] to obtain the payoffs of the players inside each coalition.Coalitional value, Shapley value, Owen value, Solidarity value

Solidarity in games with a coalition structure

A new axiomatic characterization of the two-step Shapley value (Kamijo, 2009) is presented based on a solidarity principle of the members of any union: when the game changes due to the addition or deletion of players outside the union, all members of the union will share the same gains/losses.Games with a coalition structure. Owen value. The two-step Shapley value. Solidarity.

The effect of a transfer program for the elderly in Mexico City on co-residing children's school enrollment

This paper studies whether the increase in government transfers, induced by an old-age pension program for individuals age 70 and older in Mexico, affects co-residing children's school enrollment, using a regression discontinuity analysis. Results suggest that while household composition and other household-level characteristics do not change significantly at the cutoff age for program eligibility, co-residing children's school enrollment increases significantly. This suggests that public resources for older adults might generate benefits for other age groups. An additional finding is that the increase in school enrollment takes places mostly at the program eligibility cutoff and not before. Given that the program transfer is known and potentially anticipated by individuals who are only a few years away from being eligible, this suggests that households might have credit constraints

Resiliencia y rendimiento académico en estudiantes de un instituto pedagógico privado, Lima - 2021

El objetivo de la presente investigación fue determinar la relación entre la resiliencia y el rendimiento académico en estudiantes de un Instituto Pedagógico Privado de Lima en el año 2021. Para poder cumplir con los objetivos se realizaron los procedimientos metodológicos propios de una investigación del tipo básica, de enfoque cuantitativo, el nivel de investigación es correlacional, el diseño de la investigación es no experimental, transversal y correlacional. La investigación fue censal, y se encuestó a 200 estudiantes de un Instituto Pedagógico Privado, con un cuestionario de 25 ítems para la evaluación de la resiliencia, mientras que para la variable rendimiento académico se solicitó los promedios de notas, los resultados evidenciaron una correlación de Spearman de 0.85 lo que indica una correlación positiva alta, concluyendo que la variable resiliencia con respecto a los objetivos específicos guarda una relación directa con el rendimiento académico

Reinsurance and distribution of dividends as solvency control tools in a non-life insurance portfolio: Analysis from the collective risk theory

URL del artículo en la web de la Revista: https://www.upo.es/revistas/index.php/RevMetCuant/article/view/2977El objeto de estudio del presente trabajo es el análisis del nivel de las reservas en una cartera de seguros no vida. El acercamiento a esta herramienta como indicativo de la solvencia de la cartera nos plantea una disyuntiva inicial entre la seguridad necesaria para poder responder a los siniestros acaecidos y el problema que genera a nivel financiero el hecho de inmovilizar reservas. Nos enfrentamos por tanto a la disyuntiva seguridad-rentabilidad. Como elemento equilibrador, el gestor de la cartera puede plantearse el uso de políticas de reparto de dividendos o políticas de reaseguro que se apliquen o modifiquen en el momento en que las reservas alcancen un determinado nivel. Analizando el problema desde las hipótesis clásicas del proceso de riesgo, nos planteamos en este trabajo la probabilidad de que las reservas alcancen ese nivel predeterminado, momento en el que el gestor podrá replantearse sus políticas. Esta probabilidad se obtiene para un caso general en el que los tiempos de interocurrencia y la cuantía individual del siniestro se modelizan con distribuciones Erlang. Finalmente se presentan ejemplos y resultados numéricos que pueden ayudar a entender el comportamiento de dicha probabilidad.The object of study of this paper is the analysis of the level of reserves in a non-life insurance portfolio. The approach to this tool as an indicator of the solvency of the portfolio poses an initial dilemma between the security necessary to be able to respond to the losses that have occurred and the problem generated financially by the fact of immobilizing reserves. We face therefore the disjunctive security-profitability. As a balancing element, the portfolio manager may consider the use of dividend distribution policies or reinsurance policies that are applied or modified at the time the reserves reach a certain level. Analyzing the problem from the classical hypotheses of the risk process, we consider in this work the probability that the reserves reach that predetermined level, at which time the manager may rethink his policies. This probability is obtained for a general case in which the inter-accident times and the individual amount of the loss are modeled with Erlang distributions. Finally, we present examples and numerical results that can help to understand the behavior of this probability.Universidad Pablo de Olavid

Political Advertising and Voting Intention: Evidence from Exogenous Variation in Ads Viewership

Mexico’s campaign law assigns TV and radio ads to parties according to their vote share in the previous election, and mandates the time of the day at which ads are aired to be determined randomly. We exploit this arguably exogenous variation in viewers’ exposure to political ads by different parties and longitudinal electoral survey data to estimate the effect of ads on voting intentions during Mexico’s 2012 presidential campaign. We find that political ads on both radio and TV have a positive, significant and sizeable effect on voting intentions. This effect is short-lived (about two weeks), and is stronger in the early weeks of the campaign. Ads tend to have no significant impact on voters’ knowledge of candidates’ political message, and to be more effective at convincing individuals that are more educated, and those who voted for the party in the past. Taken together these findings suggests that ads do not influence voters by conveying new information but that other mechanisms of persuasion, cantered around ads’ non-informative content, may be at work

Irrevocabilidad Relajada para Memoria Transaccional Hardware

Los sistemas comerciales que ofrecen memoria transaccional (TM) implementan un sistema hardware best-effort (BE-HTM) con limitaciones. Es necesario programar un fallback software basado en cerrojos para asegurar el progreso de la aplicación. En este artículo se propone un nuevo tipo de irrevocabilidad hardware (un modo transaccional que marca las transacciones como no abortables) para hacer frente a las limitaciones de los sistemas BE-HTM de una manera mas eficiente, y para liberar a al usuario de tener que programar un fallback. Se basa en el concepto de suscripción relajada utilizada o en el contexto de la programación de fallbacks basada o en cerrojos, donde la transacción se suscribe al cerrojo al final de la misma en lugar de al principio. El mecanismo de irrevocabilidad relajada hardware no involucra cambios en el protocolo de coherencia y se compara con su homólogo software, que proponemos como un fallback con suscripción relajada de espera escapada. También proponemos la irrevocabilidad relajada con anticipación, un mecanismo que no se puede implementar en software, y que mejora el rendimiento de las aplicaciones con múltiples reemplazos de bloques transaccionales de caché. La evaluación de las propuestas se lleva a cabo con el simulador Simics/GEMS junto con la suite de benchmarks STAMP, y se obtiene una mejora de rendimiento sobre el fallback del 14% al 28% para algunos benchmarks.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech