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

Phylodynamic inference across epidemic scales

Within-host genetic diversity and large transmission bottlenecks confound phylodynamic inference of epidemiological dynamics. Conventional phylodynamic approaches assume that nodes in a time-scaled pathogen phylogeny correspond closely to the time of transmission between hosts that are ancestral to the sample. However, when hosts harbour diverse pathogen populations, node times can substantially pre-date infection times. Imperfect bottlenecks can cause lineages sampled in different individuals to coalesce in unexpected patterns. To address realistic violations of standard phylodynamic assumptions we developed a new inference approach based on a multi-scale coalescent model, accounting for nonlinear epidemiological dynamics, heterogeneous sampling through time, non-negligible genetic diversity of pathogens within hosts, and imperfect transmission bottlenecks. We apply this method to HIV-1 and Ebola virus outbreak sequence data, illustrating how and when conventional phylodynamic inference may give misleading results. Within-host diversity of HIV-1 causes substantial upwards bias in the number of infected hosts using conventional coalescent models, but estimates using the multi-scale model have greater consistency with reported number of diagnoses through time. In contrast, we find that within- host diversity of Ebola virus has little influence on estimated numbers of infected hosts or reproduction numbers, and estimates are highly consistent with the reported number of diagnoses through time. The multi-scale coalescent also enables estimation of within-host effective population size using single sequences from a random sample of patients. We find within-host population genetic diversity of HIV-1 p17 to be 2 Nμ = 0 . 012(95% CI:0 . 0066 − 0 . 023), which is lower than estimates based on HIV envelope serial sequencing of individual patients

Evaluation of large volume yeast interfering RNA lure-and-kill ovitraps for attraction and control of Aedes mosquitoes

Aedes mosquitoes (Diptera: Culicidae), principle vectors of several arboviruses, typically lay eggs in man-made water-filled containers located near human dwellings. Given the widespread emergence of insecticide resistance, stable and biofriendly alternatives for mosquito larviciding are needed. Laboratory studies have demonstrated that inactivated yeast interfering RNA tablets targeting key larval developmental genes can be used to facilitate effective larvicidal activity while also promoting selective gravid female oviposition behaviour. Here we examined the efficacy of transferring this technology toward development of lure-and-kill ovitraps targeting Aedes aegypti (L.) and Aedes albopictus (Skuse) female mosquitoes. Insectary, simulated field and semi-field experiments demonstrated that two mosquito-specific yeast interfering RNA pesticides induce high levels of mortality among larvae of both species in treated large volume containers. Small-scale field trials conducted in Trinidad, West Indies demonstrated that large volume ovitrap containers baited with inactivated yeast tablets lure significantly more gravid females than traps containing only water and were highly attractive to both A. aegypti and A. albopictus females. These studies indicate that development of biorational yeast interfering RNA-baited ovitraps may represent a new tool for control of Aedes mosquitoes, including deployment in existing lure-and-kill ovitrap technologies or traditional container larviciding programs

Preliminary Genomic Characterization of Ten Hardwood Tree Species from Multiplexed Low Coverage Whole Genome Sequencing

Forest health issues are on the rise in the United States, resulting from introduction of alien pests and diseases, coupled with abiotic stresses related to climate change. Increasingly, forest scientists are finding genetic/genomic resources valuable in addressing forest health issues. For a set of ten ecologically and economically important native hardwood tree species representing a broad phylogenetic spectrum, we used low coverage whole genome sequencing from multiplex Illumina paired ends to economically profile their genomic content. For six species, the genome content was further analyzed by flow cytometry in order to determine the nuclear genome size. Sequencing yielded a depth of 0.8X to 7.5X, from which in silico analysis yielded preliminary estimates of gene and repetitive sequence content in the genome for each species. Thousands of genomic SSRs were identified, with a clear predisposition toward dinucleotide repeats and AT-rich repeat motifs. Flanking primers were designed for SSR loci for all ten species, ranging from 891 loci in sugar maple to 18,167 in redbay. In summary, we have demonstrated that useful preliminary genome information including repeat content, gene content and useful SSR markers can be obtained at low cost and time input from a single lane of Illumina multiplex sequence.All raw sequence data are available through NCBI SRA under project number SRP021923. Sequences containing SSRs and designed primers are attached as supplementary material

Cross amplification of 15 EST-SSR markers in the genus Fraxinus

Abstract Ash (Fraxinus, Oleaceae) species occur on most continents, within a wide range of forest tree communities. Emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), introduced into the U.S. from Asia in the late twentieth century, has caused widespread mortality, primarily in green ash, Fraxinus pennsylvanica Marsh. (Section: Melioides) and now impacts other North American ash species. The development and successful reintroduction of resistant trees requires genetic tools to evaluate population dynamics and aid in species identification. Here, we report 15 novel EST-SSR markers developed in green ash, most of which amplify and are polymorphic across 18 species of Fraxinus, including six species native to North America. The high average polymorphism information content (0.741) and allelic richness (15.3) revealed in six disparate populations of green ash indicate that these markers also have utility for investigating population dynamics in this species

Ambiente de trabajo cooperativo en internet para la educación en valores

TesisEl presente trabajo de investigación que lleva por título "AMBIENTE DE TRABAJO COOPERATIVO EN INTERNET PARA LA EDUCACION EN VALORES" responde a la necesidad de desarrollar nuevas formas de planificar y desarrollar la educación, de manera que se promueva la participación sincrónica y asincrónica entre tos sujetos que no se encuentran físicamente en el mismo lugar, ni en las mismas coordenadas temporales. El objetivo fue desarrollar un Ambiente de Trabajo Cooperativo en Internet para la educación en valores utilizando la Metodología Orientada a objetos y la Filosofía de Software Libre propiciando básicamente la reunión síncrona y. asíncrona para los miembros de la Federación de Familias para la Paz Mundial. Se ha utilizado Moodle, el cual es un . proyecto en desarrollo diseñado para dar soporte a un marco de educación social . constructivista. Esta herramienta se ha integrado al Ambiente de Trabajo Cooperativo principalmente para diseñar diferentes cursos en diferentes niveles y a diferentes usuarios. Tambíén se ha empleado los indicadores de calidad del Estándar IS0-9126, tales como funcionalidad, fiabilidad, usabilidad, eficiencia, mantenibilidad y portabilidad en una escala de 1 a 5 puntos. Se llega a la conclusión de que los ambientes de trabajo cooperativos para la educación en valores, permite mejorar el proceso de educación básicamente en la comunicación de los miembros de la Federación de Familias para la Paz Mundial cumpliendo con aprobar el estándar de calidad de software ISO 9126 en el que se observa que un 60% de los profesionales de cada país dicen que el Ambiente de Trabajo Cooperativo es bueno y un 10% afirma que es muy bueno. Palabras Claves: Ambiente de trabajo cooperativo, valores, internet, educació