Cryptic female choice favours sperm from major histocompatibility complex-dissimilar males

Cryptic female choice may enable polyandrous females to avoid inbreeding or bias offspring variability at key loci after mating. However, the role of these genetic benefits in cryptic female choice remains poorly understood. Female red junglefowl, Gallus gallus, bias sperm use in favour of unrelated males. Here, we experimentally investigate whether this bias is driven by relatedness per se, or by similarity at the major histocompatibility complex (MHC), genes central to vertebrate acquired immunity, where polymorphism is critical to an individual's ability to combat pathogens. Through experimentally controlled natural matings, we confirm that selection against related males' sperm occurs within the female reproductive tract but demonstrate that this is more accurately predicted by MHC similarity: controlling for relatedness per se, more sperm reached the eggs when partners were MHC-dissimilar. Importantly, this effect appeared largely owing to similarity at a single MHC locus (class I minor). Further, the effect of MHC similarity was lost following artificial insemination, suggesting that male phenotypic cues might be required for females to select sperm differentially. These results indicate that postmating mechanisms that reduce inbreeding may do so as a consequence of more specific strategies of cryptic female choice promoting MHC diversity in offspring

Cryptanalysis of the RSA-CEGD protocol

Recently, Nenadi\'c et al. (2004) proposed the RSA-CEGD protocol for certified delivery of e-goods. This is a relatively complex scheme based on verifiable and recoverable encrypted signatures (VRES) to guarantee properties such as strong fairness and non-repudiation, among others. In this paper, we demonstrate how this protocol cannot achieve fairness by presenting a severe attack and also pointing out some other weaknesses.Comment: 8 pages, 1 figur

Crossing the Vascular Wall: Common and Unique Mechanisms Exploited by Different Leukocyte Subsets during Extravasation

Leukocyte extravasation is one of the essential and first steps during the initiation of inflammation. Therefore, a better understanding of the key molecules that regulate this process may help to develop novel therapeutics for treatment of inflammation-based diseases such as atherosclerosis or rheumatoid arthritis. The endothelial adhesion molecules ICAM-1 and VCAM-1 are known as the central mediators of leukocyte adhesion to and transmigration across the endothelium. Engagement of these molecules by their leukocyte integrin receptors initiates the activation of several signaling pathways within both leukocytes and endothelium. Several of such events have been described to occur during transendothelial migration of all leukocyte subsets, whereas other mechanisms are known only for a single leukocyte subset. Here, we summarize current knowledge on regulatory mechanisms of leukocyte extravasation from a leukocyte and endothelial point of view, respectively. Specifically, we will focus on highlighting common and unique mechanisms that specific leukocyte subsets exploit to succeed in crossing endothelial monolayers

Posicionamiento de la pequeña y mediana empresa familiar sobre la responsabilidad social

Pese al importante papel que juega en la economía la empresa familiar, son pocos los estudios sobre la misma en relación a la responsabilidad social ejercida por ésta y sobre la percepción y el posicionamiento respecto del concepto responsabilidad social . El presente trabajo de investigación, persigue descubrir qué piensa la empresa familiar de Córdoba y provincia sobre la responsabilidad social y obtener una clasificación de las empresas en función del enfoque de responsabilidad social mostrado. Con tal objetivo se seleccionaron 165 empresas familiares con sede en Córdoba y provincia, a las que se les solicitó rellenaran un cuestionario, recibiendo contestación de 68 de ellas . Se procedió a realizar una clasificación ascendente jerárquica al objeto de descubrir grupos de posicionamiento similares de empresas familiares respecto de la responsabilidad social. Los resultados obtenidos arrojan conclusiones que sugieren continuar con la investigación . Futuras líneas de investigación consistirían en establecer indicadores que permitieran mediar la RS de pequeñas y medianas empresas siguiendo las pautas del estudio marcadas en “One report. Integrated reporting for a sustainable strategy”. (Eccles y Krzus, 2010)Even though there is agreement on the impact the family businesses have on economy, there are few researches relating family businesses and corporate social responsibility. This paper aims to search out what is the positioning the family business adapt respect to corporate social responsibility and try to classify the family businesses depending on their conceptions. For that porpouse a population of one hundred and sixty five Spanish family firms were questioned getting a response from sixty eight family businesses. The results obtained show that there is a vast range of different possible positions the family firms can take and how future investigation lines should focus on the development of new corporate social responsibility measures for small and medium size family firms