Dynamic Variation in Sexual Contact Rates in a Cohort of HIV-Negative Gay Men

Human immunodeficiency virus (HIV) transmission models that include variability in sexual behavior over time have shown increased incidence, prevalence, and acute-state transmission rates for a given population risk profile. This raises the question of whether dynamic variation in individual sexual behavior is a real phenomenon that can be observed and measured. To study this dynamic variation, we developed a model incorporating heterogeneity in both between-person and within-person sexual contact patterns. Using novel methodology that we call iterated filtering for longitudinal data, we fitted this model by maximum likelihood to longitudinal survey data from the Centers for Disease Control and Prevention's Collaborative HIV Seroincidence Study (1992–1995). We found evidence for individual heterogeneity in sexual behavior over time. We simulated an epidemic process and found that inclusion of empirically measured levels of dynamic variation in individual-level sexual behavior brought the theoretical predictions of HIV incidence into closer alignment with reality given the measured per-act probabilities of transmission. The methods developed here provide a framework for quantifying variation in sexual behaviors that helps in understanding the HIV epidemic among gay men

Behaviour of compacted silt used to construct flood embankment

This paper investigates the unsaturated mechanical behaviour of a fill material sampled from flood embankments located along the Bengawan Solo River in Indonesia. In order to gain a better understanding of this fill material, in situ tests were carried out alongside an extensive laboratory programme. Two different phenomena related to changes in moisture content of the embankment fill material are experimentally studied herein: (a) volumetric collapse and (b) variation in shear strength with suction. At low densities, similar to those found in situ, the material exhibited significant volumetric collapse behaviour. Triaxial tests carried out under saturated, suction-controlled and constant water content conditions indicate that the shear strength of the material increased with suction; in particular the effective angle of friction increased from 24.9 degrees under saturated conditions to 35.8 degrees under air-dried conditions

CRP-cAMP mediates silencing of Salmonella virulence at the post-transcriptional level

Invasion of epithelial cells by Salmonella enterica requires expression of genes located in the pathogenicity island I (SPI-1). The expression of SPI-1 genes is very tightly regulated and activated only under specific conditions. Most studies have focused on the regulatory pathways that induce SPI-1 expression. Here, we describe a new regulatory circuit involving CRP-cAMP, a widely established metabolic regulator, in silencing of SPI-1 genes under non-permissive conditions. In CRP-cAMP-deficient strains we detected a strong upregulation of SPI-1 genes in the mid-logarithmic growth phase. Genetic analyses revealed that CRP-cAMP modulates the level of HilD, the master regulator of Salmonella invasion. This regulation occurs at the post-transcriptional level and requires the presence of a newly identified regulatory motif within the hilD 3’UTR. We further demonstrate that in Salmonella the Hfq-dependent sRNA Spot 42 is under the transcriptional repression of CRP-cAMP and, when this transcriptional repression is relieved, Spot 42 exerts a positive effect on hilD expression. In vivo and in vitro assays indicate that Spot 42 targets, through its unstructured region III, the 3’UTR of the hilD transcript. Together, our results highlight the biological relevance of the hilD 3’UTR as a hub for post-transcriptional control of Salmonella invasion gene expression.Spanish Ministry of Economy and Competitiveness BIO2010-15417 BIO2013-44220-R AGL2013-45339-RRecerCaixa program 2012/ACUP/00048Catalonian government 2017SGR49

First genotyping of Giardia duodenalis and prevalence of enteroparasites in children from Tetouan (Morocco).

Intestinal parasites are common in the Moroccan population. Enteroparasites in children from four schools in urban and rural areas of Tetouan (Morocco) were studied to treat these children and to design prevention and control programs. A total of 673 children were examined. The prevalence of parasitized children was 51%. The average number of enteroparasites was half in urban areas than in rural areas. Multiple parasitism appeared in 30% of the samples presenting two, three, or four parasites. The most prevalent parasite was Blastocystis hominis (64%). Giardia duodenalis was the most frequent pathogen, with an overall prevalence of 20% (24% in rural areas and 16% in urban areas). Other pathogenic enteroparasites were Cyclospora cayetanensis (5% in rural and urban areas), Iodamoeba butschlii, Hymenolepis spp., Trichuris trichiura and Enterobius vermicularis, with prevalence lower than 2%. In this work, G. duodenalis genotypes were molecularly characterized by a study of the glutamate dehydrogenase (gdh) and 18S rRNA genes. This is the first study of molecular characterization of G. duodenalis in Moroccan children, and the sequence analysis revealed both Assemblage A (AII) and Assemblage B (BIII, BIV), with the predominance of Assemblage BIV (73%)

Enterprise 4.0 – the emerging digital transformed enterprise?

Information Systems are at the core of all businesses and cover almost all aspects of organizational life. The convergence of computer capabilities, such as the potential to process large volumes of data in a very short time, the growth in Internet usage and the increase in the ability to capture and leverage knowledge in digital format are, in this context, the main enablers of the so called digital transformation of organizations. While the technology enablers allow the production, sharing and management of information and knowledge within the organization between peers and other stakeholders, besides empowering the improvement and innovation of the organizational processes, they also require the updating of the supporting IS. Thus, using technologies in organizations within the context of Digital Transformation (DT) requires an exercise in understanding how to demonstrate their usefulness in relation to the creation, access and sharing of contents and IS improvements in a safe way. This paper provides a comprehensive view of a new context of labour faced within DT of organizations, which we term Enterprise 4.0 and which we propose to be implemented through the m_CSDIT framework, so as to improve the organizational well-being considering the collective intelligence and agility dimensions.Project Management(undefined

Solving random diffusion models with nonlinear perturbations by the Wiener-Hermite expansion method

[EN] This paper deals with the construction of approximate series solutions of random nonlinear diffusion equations where nonlinearity is considered by means of a frank small parameter and uncertainty is introduced through white noise in the forcing term. For the simpler but important case in which the diffusion coefficient is time independent, we provide a Gaussian approximation of the solution stochastic process by taking advantage of the Wiener¿Hermite expansion together with the perturbation method. In addition, approximations of the main statistical functions associated with a solution, such as the mean and variance, are computed. Numerical values of these functions are compared with respect to those obtained by applying the Runge¿Kutta second-order stochastic scheme as an illustrative example.This work was partially supported by the Spanish M.C.Y.T. and FEDER grants MTM2009-08587, TRA2007-68006-C02-02, DPI2010-20891-C02-01 as well as the Universidad Politécnica de Valencia grant PAID-06-09 (ref. 2588).Cortés López, JC.; Romero Bauset, JV.; Roselló Ferragud, MD.; Santamaría Navarro, C. (2011). Solving random diffusion models with nonlinear perturbations by the Wiener-Hermite expansion method. Computers and Mathematics with Applications. 61(8):1946-1950. https://doi.org/10.1016/j.camwa.2010.07.057S1946195061

The role of forest genetic resources in responding to biotic and abiotic factors in the context of anthropogenic climate change

The current distribution of forest genetic resources on Earth is the result of a combination of natural processes and human actions. Over time, tree populations have become adapted to their habitats including the local ecological disturbances they face. As the planet enters a phase of human-induced climate change of unprecedented speed and magnitude, however, previously locally-adapted populations are rendered less suitable for new conditions, and ‘natural’ biotic and abiotic disturbances are taken outside their historic distribution, frequency and intensity ranges. Tree populations rely on phenotypic plasticity to survive in extant locations, on genetic adaptation to modify their local phenotypic optimum or on migration to new suitable environmental conditions. The rate of required change, however, may outpace the ability to respond, and tree species and populations may become locally extinct after specific, but as yet unknown and unquantified, tipping points are reached. Here, we review the importance of forest genetic resources as a source of evolutionary potential for adaptation to changes in climate and other ecological factors. We particularly consider climate-related responses in the context of linkages to disturbances such as pests, diseases and fire, and associated feedback loops. The importance of management strategies to conserve evolutionary potential is emphasised and recommendations for policy-makers are provided