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

Multiple imputation approach for interval-censored time to HIV RNA viral rebound within a mixed effects Cox model

This is the peer reviewed version of the following article: “Alarcón-Soto, Y, Langohr K., Fehér, C., García, F., and Gómez, G. (2018) Multiple imputation approach for interval-censored time to HIV RNA viral rebound within a mixed effects Cox Model.Biometrical journal, December 13th ”which has been published in final form at [doi: 10.1002/bimj.201700291]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.We present a method to fit a mixed effects Cox model with interval-censored data. Our proposal is based on a multiple imputation approach that uses the truncated Weibull distribution to replace the interval-censored data by imputed survival times and then uses established mixed effects Cox methods for right-censored data. Interval-censored data were encountered in a database corresponding to a recompilation of retrospective data from eight analytical treatment interruption (ATI) studies in 158 human immunodeficiency virus (HIV) positive combination antiretroviral treatment (cART) suppressed individuals. The main variable of interest is the time to viral rebound, which is defined as the increase of serum viral load (VL) to detectable levels in a patient with previously undetectable VL, as a consequence of the interruption of cART. Another aspect of interest of the analysis is to consider the fact that the data come from different studies based on different grounds and that we have several assessments on the same patient. In order to handle this extra variability, we frame the problem into a mixed effects Cox model that considers a random intercept per subject as well as correlated random intercept and slope for pre-cART VL per study. Our procedure has been implemented in R using two packages: truncdist and coxme, and can be applied to any data set that presents both interval-censored survival times and a grouped data structure that could be treated as a random effect in a regression model. The properties of the parameter estimators obtained with our proposed method are addressed through a simulation study.Peer ReviewedPostprint (author's final draft

La transparencia organizativa y económica en la Web de las fundaciones: un estudio empírico para España

A través de los estudios realizados durante las últimas décadas ha quedado demostrado que la transparencia en el sector no lucrativo en general y en las fundaciones en particular, es un elemento clave para la mejora de la confianza de los agentes interesados en la organización. Dicha transparencia puede ser considerada desde diferentes ámbitos y conseguida a través de distintos canales o medios. Este trabajo se centra en el análisis de la transparencia organizativa y económica de las fundaciones, que es mostrada a través de la información que voluntariamente ofrecen estas entidades en sus páginas Web. Antes de pasar a exponer el trabajo empírico, se realiza una revisión teórica de algunos de los estudios publicados sobre el concepto de transparencia y la importancia en el ámbito no lucrativo. Este marco teórico se ha centrado en la rendición de cuentas que realizan, relacionada con su función social y su gestión, desde la perspectiva de la transparencia informativa a través de la Web. Bajo este enfoque se ha diseñado un índice de transparencia que se refiere a la información que las fundaciones ofrecen en sus Webs de forma voluntaria. El índice ha sido elaborado ad hoc y se ha aplicado a un grupo de grandes fundaciones empresariales, obteniéndose datos de carácter descriptivo e inferencial, por cuanto se determina, mediante un análisis de regresión lineal múltiple, si hay correlación estadística entre la transparencia económica y la transparencia organizativa obtenida a través de la información publicada on line y cuantificada en las variables resultantes del índice. A la luz del análisis se obtienen conclusiones acerca del nivel de transparencia que tienen las fundaciones en lo que se refiere a su información organizativa y económica y la relación explicativa entre ambos tipos

Extraordinary MHC class II B diversity in a non-passerine, wild bird: the Eurasian Coot Fulica atra (Aves: Rallidae)

The major histocompatibility complex (MHC) hosts the most polymorphic genes ever described in vertebrates. The MHC triggers the adaptive branch of the immune response, and its extraordinary variability is considered an evolutionary consequence of pathogen pressure. The last few years have witnessed the characterization of the MHC multigene family in a large diversity of bird species, unraveling important differences in its polymorphism, complexity, and evolution. Here, we characterize the first MHC class II B sequences isolated from a Rallidae species, the Eurasian Coot Fulica atra. A next-generation sequencing approach revealed up to 265 alleles that translated into 251 different amino acid sequences (b chain, exon 2) in 902 individuals. Bayesian inference identified up to 19 codons within the presumptive peptide-binding region showing pervasive evidence of positive, diversifying selection. Our analyses also detected a significant excess of high-frequency segregating sites (average Tajima’s D = 2.36, P < 0.05), indicative of balancing selection. We found one to six different alleles per individual, consistent with the occurrence of at least three MHC class II B gene duplicates. However, the genotypes comprised of three alleles were by far the most abundant in the population investigated (49.4%), followed by those with two (29.6%) and four (17.5%) alleles. We suggest that these proportions are in agreement with the segregation of MHC haplotypes differing in gene copy number. The most widespread segregating haplotypes, according to our findings, would contain one single gene or two genes. The MHC class II of the Eurasian Coot is a valuable system to investigate the evolutionary implications of gene copy variation and extensive variability, the greatest ever found, to the best of our knowledge, in a wild population of a non-passerine birdPeer reviewe

Use of tomato and cucumber horticulture by-products in goat diets: effects o nrumen fermentation and microbial communities in batch and continuous cultures

Two in vitro experiments were conducted to analyse the effects of replacing dietary barley grain with wastes of tomato and cucumber fruits and a 1 : 1 tomato : cucumber mixture on rumen fermentation characteristics and microbial abundance. The control (CON) substrate contained 250 g/kg of barley grain on a dry matter (DM) basis, and another 15 substrates were formulated by replacing 50, 100, 150, 200 or 250 g of barley grain/kg with the same amount (DM basis) of tomato or cucumber fruits or 1 : 1 tomato : cucumber mixture. In Expt 1, all substrates were incubated in batch cultures with rumen micro-organisms from goats for 24 h. Increasing amounts of tomato, cucumber and the mixture of both fruits in the substrate increased final pH and gas production, without changes in final ammonia-nitrogen (NH3-N) concentrations, substrate degradability and total volatile fatty acid (VFA) production, indicating that there were no detrimental effects of any waste fruits on rumen fermentation. Therefore, in Expt 2 the substrates including 250 g of waste fruits (T250, C250 and M250 for tomato, cucumber and the mixture of both fruits, respectively) and the CON substrate were incubated in single-flow continuous-culture fermenters for 8 days. Total VFA production did not differ among substrates, but there were differences in VFA profile. Molar proportions of propionate, isobutyrate and isovalerate were lower and acetate : propionate ratio was greater for T250 compared with CON substrate. Fermentation of substrates containing cucumber (C250 and M250) resulted in lower proportions of acetate, isobutyrate and isovalerate and acetate : propionate ratio, but greater butyrate proportions than the CON substrate. Carbohydrate degradability and microbial N synthesis tended to be lower for substrates containing cucumber than for the CON substrate, but there were no differences between CON and T250 substrates. Abundance of total bacteria, Fibrobacter succinogenes and Ruminococcus flavefaciens, fungi, methanogenic archaea and protozoa were similar in fermenters fed T250 and CON substrates, but fermenters fed C250 and M250 substrates had lower abundances of R. flavefaciens, fungi and protozoa than those fed the CON substrate. Results indicated that tomato fruits could replace dietary barley grain up to 250 g/kg of substrate DM without noticeable effects on rumen fermentation and microbial populations, but the inclusion of cucumber fruits at 250 g/kg of substrate DM negatively affected some microbial populations as it tended to reduce microbial N synthesis and changed the VFA profile. More studies are needed to identify the dietary inclusion level of cucumber which produces no detrimental effects on rumen fermentation and microbial growth

Influencia del tipo de filtrado y tratamiento con Stomacher del fluido ruminal de ovejas en las poblaciones microbianas del inóculo

Four rumen-fistulated sheep fed a 66:34 alfalfa hay:concentrate diet were used as donors to investigate the effect of rumen contents’ treatment on microbial populations in the resulting fluid. Rumen contents were sampled from each individual sheep and subjected to the following treatments: SQ: squeezed through 4 layers of cheesecloth; FIL: SQ treatment and further filtration through a 100-μm nylon cloth; STO: reated with a Stomacher® for 3 min at 230 rev min-1 and followed by SQ. Microbial populations in the fluid were analysed by real-time PCR and bacterial diversity was assessed by the automated ribosomal intergenic spacer analysis (ARISA) of the 16S ribosomal DNA. Bacterial DNA concentrations and relative abundance of Ruminococcus flavefaciens, arqueal and fungal DNA did not differ (P>0.05) between treatments. In contrast, STO treatment decreased (P0.05) between treatments either in the Shannon index or in the number of peaks in the ARISA electropherograms, indicating no effect on bacterial diversity. Studies analyzing the influence on the tested methods on fermentation characteristics of different substrates when the fluid is used as inoculum is required

Organizational and financial transparency in the website of the foundations: an empirical study for Spain

A través de los estudios realizados durante las últimas décadas ha quedado demostrado que la transparencia en el sector no lucrativo en general y en las fundaciones en particular, es un elemento clave para la mejora de la confianza de los agentes interesados en la organización. Dicha transparencia puede ser considerada desde diferentes ámbitos y conseguida a través de distintos canales o medios.Este trabajo se centra en el análisis de la transparencia organizativa y económica de las fundaciones, que es mostrada a través de la información que voluntariamente ofrecen estas entidades en sus páginas Web. Antes de pasar a exponer el trabajo empírico, se realiza una revisión teórica de algunos de los estudios publicados sobre el concepto de transparencia y la importancia en el ámbito no lucrativo. Este marco teórico se ha centrado en la rendición de cuentas que realizan, relacionada con su función social y su gestión, desde la perspectiva de la transparencia informativa a través de la Web.Bajo este enfoque se ha diseñado un índice de transparencia que se refiere a la información que las fundaciones ofrecen en sus Webs de forma voluntaria. El índice ha sido elaborado ad hoc y se ha aplicado a un grupo de grandes fundaciones empresariales, obteniéndose datos de carácter descriptivo e inferencial, por cuanto se determina, mediante un análisis de regresión lineal múltiple, si hay correlación estadística entre la transparencia económica y la transparencia organizativa obtenida a través de la información publicada on line y cuantificada en las variables resultantes del índice.A la luz del análisis se obtienen conclusiones acerca del nivel de transparencia que tienen las fundaciones en lo que se refiere a su información organizativa y económica y la relación explicativa entre ambos tipos.Transparency in nonprofit sector and foundations, as an element to enhance the confidence of stakeholders in the organization, is a fact shown by several studies in recent decades. Transparency can be considered in various fields and through different channels. In our study we focused on the analysis of the organizational and economic transparency of foundations, shown through the voluntary information on their Website. We review the theoretical previous studies published to put to the foundations within the framework of the social economy. This theoretical framework has focused on accountability that make foundations in relation to its social function and its management, especially since the most recent focus of information transparency across the Website.In this theoretical framework was made an index to quantify the voluntary information which is shown on its website. This index has been developed ad hoc for this study and applied to a group of large corporate foundations.With the application of these data are obtained two kind of results, to a descriptive level and to a inferential level.We analyzed the statistical correlation between economic transparency and organizational transparency offered in the Website through quantified variables by a multiple linear regression. This empirical analysis allows us to draw conclusions about the level of transparency offered by these organizations in relation to their organizational and financial information, as well as explain the relation between them