Identification and characterization of Rhipicephalus (Boophilus) microplus candidate protective antigens for the control of cattle tick infestations

The cattle ticks, Rhipicephalus (Boophilus) spp., affect cattle production in tropical and subtropical regions of the world. Tick vaccines constitute a cost-effective and environmentally friendly alternative to tick control. The recombinant Rhipicephalus microplus Bm86 antigen has been shown to protect cattle against tick infestations. However, variable efficacy of Bm86-based vaccines against geographic tick strains has encouraged the research for additional tick-protective antigens. Herein, we describe the analysis of R. microplus glutathione-S transferase, ubiquitin (UBQ), selenoprotein W, elongation factor-1 alpha, and subolesin (SUB) complementary DNAs (cDNAs) by RNA interference (RNAi) in R. microplus and Rhipicephalus annulatus. Candidate protective antigens were selected for vaccination experiments based on the effect of gene knockdown on tick mortality, feeding, and fertility. Two cDNA clones encoding for UBQ and SUB were used for cattle vaccination and infestation with R. microplus and R. annulatus. Control groups were immunized with recombinant Bm86 or adjuvant/saline. The highest vaccine efficacy for the control of tick infestations was obtained for Bm86. Although with low immunogenic response, the results with the SUB vaccine encourage further investigations on the use of recombinant subolesin alone or in combination with other antigens for the control of cattle tick infestations. The UBQ peptide showed low immunogenicity, and the results of the vaccination trial were inconclusive to assess the protective efficacy of this antigen. These experiments showed that RNAi could be used for the selection of candidate tick-protective antigens. However, vaccination trials are necessary to evaluate the effect of recombinant antigens in the control of tick infestations, a process that requires efficient recombinant protein production and formulation systems

Diffusive Transport Enhanced by Thermal Velocity Fluctuations

We study the contribution of advection by thermal velocity fluctuations to the effective diffusion coefficient in a mixture of two indistinguishable fluids. The enhancement of the diffusive transport depends on the system size L and grows as \ln(L/L_0) in quasi two-dimensional systems, while in three dimensions it scales as L_0^{-1}-L^{-1}, where L_0 is a reference length. The predictions of a simple fluctuating hydrodynamics theory are compared to results from particle simulations and a finite-volume solver and excellent agreement is observed. Our results conclusively demonstrate that the nonlinear advective terms need to be retained in the equations of fluctuating hydrodynamics when modeling transport in small-scale finite systems.Comment: To appear in Phys. Rev. Lett., 201

Comparación de métodos para modelar la aquiescencia en escalas multidimensionales parcialmente balanceadas.

Background: The inclusion of direct and reversed items in scales is a commonly-used strategy to control acquiescence bias. However, this is not enough to avoid the distortions produced by this response style in the structure of covariances and means of the scale in question. This simulation study provides evidence on the performance of two different procedures for modelling the influence of acquiescence bias on partially balanced multidimensional scales: a method based on exploratory factor analysis (EFA) with target rotation, and a method based on random intercept factor analysis (RIFA). Method: The independent variables analyzed in a simulation study were sample size, number of items per factor, balance of substantive loadings of direct and reversed items, size and heterogeneity of acquiescence loadings, and inter-factor correlation. Results: The RIFA method had better performance over most of the conditions, especially for the balanced conditions, although the variance of acquiescence factor loadings had a certain impact. In relation to the EFA method, it was severely affected by a low degree of balance. Conclusions: RIFA seems the most robust approach, but EFA also remains a good alternative for medium and fully balanced scales.Antecedentes: la inclusión de ítems directos e inversos en escalas es una estrategia comúnmente utilizada para controlar el sesgo de aquiescencia. No obstante, esto es insufi ciente para evitar las distorsiones producidas por este estilo de respuesta en la estructura de covarianzas y medias de la escala. El presente estudio de simulación aporta evidencia sobre el rendimiento de dos procedimientos para controlar la infl uencia del sesgo de aquiescencia en escalas multidimensionales parcialmente balanceadas: un método basado en análisis factorial exploratorio con rotación target (EFA), y un método basado en el análisis factorial confi rmatorio con intercepto aleatorio (RIFA). Método: las variables independientes del estudio de simulación fueron: tamaño muestral, número de ítems por factor, balanceo de los pesos sustantivos de los ítems directos e inversos, tamaño y heterogeneidad de los pesos en aquiescencia, y correlación entre factores. Resultados: el método RIFA tiene mejor funcionamiento en general, especialmente para las condiciones balanceadas, aunque la varianza de los pesos de aquiescencia tuvo impacto en su rendimiento. El método EFA se ve principalmente afectado en la situación de bajo balanceo. Conclusiones: el RIFA parece la aproximación más robusta, aunque el EFA se mantiene como una alternativa a considerar para escalas con balanceo medio o completoThis research was partially supported by Ministerio de Ciencia, Innovación y Universidades, Spain (Grant PSI2017-85022-P), European Social Fund, and Cátedra de Modelos y Aplicaciones Psicométricas (Instituto de Ingeniería del Conocimiento and Autonomous University of Madrid)

Cluster Origin of Triple Star HD 188753 and its Planet

The recent discovery by M. Konacki of a ``hot Jupiter'' in the hierarchical triple star system HD 188753 challenges established theories of giant-planet formation. If the orbital geometry of the triple has not changed since the birth of the planet, then a disk around the planetary host star would probably have been too compact and too hot for a Jovian planet to form by the core-accretion model or gravitational collapse. This paradox is resolved if the star was initially either single or had a much more distant companion. It is suggested here that a close multi-star dynamical encounter transformed this initial state into the observed triple, an idea that follows naturally if HD 188753 formed in a moderately dense stellar system--perhaps an open cluster--that has since dissolved. Three distinct types of encounters are investigated. The most robust scenario involves an initially single planetary host star that changes places with the outlying member of a pre-existing hierarchical triple.Comment: Accepted by ApJL; minor changes from origina

Undergraduate student gender, personality and academic confidence

Within a socio-situational and socio-behavioural context, the relationships between the Big Five personality traits and the academic confidence of university students and how they differed by sex of the student was explored. Previous research has identified both conscientiousness and academic confidence as being linked to university performance. In respect of sex, female students have been found to score higher on all of the Big Five measures, whereas the relationship between sex and academic confidence has been mixed. Using self-report measures of personality and academic confidence from 1523 Spanish students, it was found that the female students were more confident in their grades, studying and attendance components of academic confidence and had higher scores for conscientiousness, agreeableness and neuroticism personality measures. A multiple regression analysis found that personality predicts academic confidence, with conscientiousness being the trait that statistically loaded the most strongly. This research further confirms the validity of the Academic Behavioural Confidence scale and suggests that measures of personality and, especially, academic confidence could be usefully used in student support situations to help students acquire the strategies and skills that lead to successful university study. It is suggested that further research in the area needs to include outcome or achievement measures and measures of hypothetical constructs, such as personality and academic confidence, that go beyond self-report measures