Fast Bayesian Variable Screenings for Binary Response Regressions with Small Sample Size.

Screening procedures play an important role in data analysis, especially in high-throughput biological studies where the datasets consist of more covariates than independent subjects. In this article, a Bayesian screening procedure is introduced for the binary response models with logit and probit links. In contrast to many screening rules based on marginal information involving one or a few covariates, the proposed Bayesian procedure simultaneously models all covariates and uses closed-form screening statistics. Specifically, we use the posterior means of the regression coefficients as screening statistics; by imposing a generalized g-prior on the regression coefficients, we derive the analytical form of their posterior means and compute the screening statistics without Markov chain Monte Carlo implementation. We evaluate the utility of the proposed Bayesian screening method using simulations and real data analysis. When the sample size is small, the simulation results suggest improved performance with comparable computational cost.

Maternal infant feeding styles and the risk for overweight in Caribbean infants

OBJECTIVE: To examine the role of maternal feeding styles on the risk of overweight in a cohort of Caribbean infants. DESIGN AND METHODS: Data from mother-child pairs participating in an intervention study from 3 Caribbean islands were analysed. At recruitment, maternal and infant socio demographic and anthropometric data were collected and maternal depression assessed usingthe Center for Epidemiology Studies (CES) depression scale questionnaire. At 12 months, feeding styles was assessed in mothers by questionnaire. Factor analysis yielded five feeding styles: uninvolved, indulgent, forceful, restrictive and responsive. Infant length and weight were measured using standardized protocols at 18 months and BMI Z-scores were calculated from World Health Organization 2006 growth charts. Z-scores ≥ 1 were classified as at risk for overweight. Associations between maternal feeding styles and risk for infant overweight were assessed using multilevel logistic regression accounting for country and clinic. RESULTS: Data from 366 mother-child pairs (mean age 26.08ñ7.05 years, 55.5% high school graduates, 67.5% employed) were evaluated. No association was found between uninvolved, indulgent, forceful and responsive feeding styles with risk for infant overweight. Restrictive feeding was associated with increased risk for infant overweight (β=0.46; 95%CI=0.21,0.72) and the association remained after adjustment for infant birth weight, maternal age, education, socio-economic status and BMI (β=0.48;95%CI=0.21,0.74). This associationstrengthened after adjusting for maternal depression (β=0.55;95%CI=0.27,0.82). CONCLUSION: Restrictive feeding increased the risk of infant overweight. Overweight/obesity prevention interventions focusing on identifying suitable maternal feeding control as well as larger studies aimed at understanding the underlying mechanisms for this association are important approaches to tackling childhood overweight.

Role of fathers in overweight prevention: an analysis of a Caribbean cohort

OBJECTIVE: To investigate the role of parental characteristics and maternal perceptions of ways fathers might influence risk of overweight in Caribbean infants. DESIGN AND METHODS: Data from participants in a three island parenting intervention study were analyzed. Maternal and paternal characteristics were obtained by questionnaire at enrolment (infant age 6-10 weeks). At 18 months, 501 infants (82.9% of cohort) had weight and length measured using standardized methods and body mass index (BMI-Z scores) calculated. Participants with Z scores ≥1 were classified as at risk of overweight. Multi-level logistic regression analyses were utilized to assess the effect of parents’ characteristics on the risk of infant overweight. Additionally data from 4 focus group discussions among mothers with infants (6 - 24 months) in Jamaica were used to explore how any effects might be mediated. RESULTS: Overall 20.6% of the children were classified as at risk of overweight. The father was present in 52% of households. Fathers’ presence and higher paternal occupation level were associated with reduced risk of overweight after controlling for maternal age, education, occupation, receptive vocabulary and SES score. The presence of the father in the home (OR[95% CI] =0.78 (0.62 - 0.99)) decreased the odds of overweight in these infants. From focus group discussions mothers reported that the majority of fathers encouraged breastfeeding, healthier meal choices and discouraged use of unhealthy snacks. CONCLUSION: More information on paternal characteristics should be collected in future studies of childhood obesity. Interventions to address childhood overweight should include fathers as part of the strategy.

A parenting intervention delivered at routine primary health visits improved child cognitive development and parenting knowledge

OBJECTIVE: Several agencies have recommended integrating early child development interventions with health services. We developed and evaluated a parent training programme integrated into primary health visits. DESIGN AND METHODS: A cluster randomised trial conducted in Jamaica, Antigua and St Lucia with health centre as the unit of randomization. Fifteen centres were randomised to control (n=250 mother-child pairs) and 14 to intervention (n=251). Participants were recruited at the 6-8 week child health visit. Intervention was provided at routine health visits from age 3-18 months and comprised short films of child development messages followed by discussion and demonstration led by community health workers, and mothers’ practice of activities. Nurses distributed message cards and a few play materials. Primary outcomes were child development, measured 2 weeks after the 18 month visit, with the Griffiths Mental Development Scales and the Communicative Development Inventory (CDI). RESULTS: 85% of enrolled children were tested (control = 210; intervention=216). Loss did not differ by group. Multilevel analyses showed significant intervention benefits for cognitive development, (3.09 points; 95% CI 1.31, 4.87), effect size 0.30 SD. There were no benefits to language or hand and eye subscales, or CDI vocabulary score. Of six secondary outcomes there was a significant benefit to parenting knowledge, treatment effect 1.59 (95% CI 1.01 to 2.17), effect size 0.40. CONCLUSION: An innovative parenting intervention, requiring no additional clinic staff or mothers’ time, can be integrated into health services, with benefits to cognitive development and parent knowledge.

Mating system contributes only slightly to female maintenance in gynodioecious Geranium maculatum (Geraniaceae).

Gynodioecy, the co-occurrence of female and hermaphroditic individuals within a population, is an important intermediate in the evolution of separate sexes. The first step, female maintenance, requires females to have higher seed fitness compared with hermaphrodites. A common mechanism thought to increase relative female fitness is inbreeding depression avoidance, the magnitude of which depends on hermaphroditic selfing rates and the strength of inbreeding depression. Less well studied is the effect of biparental inbreeding on female fitness. Biparental inbreeding can affect relative female fitness only if its consequence or frequency differs between sexes, which could occur if sex structure and genetic structure both occur within populations. To determine whether inbreeding avoidance and/or biparental inbreeding can account for female persistence in Geranium maculatum, we measured selfing and biparental inbreeding rates in four populations and the spatial genetic structure in six populations. Selfing rates of hermaphrodites were low and did not differ significantly from zero in any population, leading to females gaining at most a 1-14% increase in seed fitness from inbreeding avoidance. Additionally, although significant spatial genetic structure was found in all populations, biparental inbreeding rates were low and only differed between sexes in one population, thereby having little influence on female fitness. A review of the literature revealed few sexual differences in biparental inbreeding among other gynodioecious species. Our results show that mating system differences may not fully account for female maintenance in this species, suggesting other mechanisms may be involved.

Inbreeding depression in male gametic performance.

One key objective in evolutionary ecology is to understand the magnitude of inbreeding depression expressed across sex-specific components of fitness. One major component of male fitness is fertilization success, which depends on male gametic performance (sperm and pollen performance in animals and plants, respectively). Inbreeding depression in male gametic performance could create sex-specific inbreeding depression in fitness, increase the benefit of inbreeding avoidance and reduce the efficacy of artificial insemination and pollination. However, there has been no assessment of the degree to which inbreeding generally depresses male gametic performance and hence post-copulatory or post-pollination fertilization success. Because inbreeding depression is understood to be a property of diploid entities, it is not clear what degree of inbreeding depression in haploid gametic performance should be expected. Here, we first summarize how inbreeding depression in male gametic performance could potentially arise through gene expression in associated diploid cells and/or reduced genetic diversity among haploid gametes. We then review published studies that estimate the magnitude of inbreeding depression in traits measuring components of sperm or pollen quantity, quality and competitiveness. Across 51 published studies covering 183 study traits, the grand mean inbreeding load was approximately one haploid lethal equivalent, suggesting that inbreeding depresses male gametic performance across diverse systems and traits. However, there was an almost complete lack of explicit estimates from wild populations. Future studies should quantify inbreeding depression in systematic sets of gametic traits under naturally competitive and noncompetitive conditions and quantify the degree to which gamete phenotypes and performance reflect haploid vs. diploid gene expression.

Building human capacity through early childhood intervention: the Child Development Research programme at the Tropical Medicine Research Institute, The University of the West Indies, Kingston, Jamaica / Construcción de la capacidad humana mediante intervención en la primera infancia: Programa de Investigación del Desarrollo Infantil en el Instituto de Investigación de Medicina Tropical, Universidad de West Indies, Kingston, Jamaica

Research conducted by the Child Development Research Group in the Tropical Medicine Research Institute has made significant contributions to the understanding of the importance of early nutrition and the home environment for children's development and the impact of psychosocial stimulation for disadvantaged and/or undernourished children. The work has provided critical evidence that has contributed to the increasing attention given to early childhood development in the work and policies of agencies such as the World Bank, World Health Organization (WHO) and United Nations Children Fund (UNICEF). This review concerns research which documented the impact of malnutrition on children's development and for the first time demonstrated the benefits and necessity of psychosocial stimulation for improvement in development. Subsequent research was critical in establishing the importance of linear growth retardation (stunting) as a risk factor for poor child development. A twenty-two-year study of stunted children has demonstrated benefits through to adulthood in areas such as educational attainment, mental health and reduced violent behaviour, from an early childhood home visiting programme that works through mothers to promote their children's development. The group's research has also demonstrated that it is feasible and effective to integrate the stimulation intervention into primary care services with benefits to children's development and mothers' child rearing knowledge and practices. The group is currently conducting a study to provide information needed for scaling-up of parenting programmes through evaluation of a new approach to improving parenting through health centres and a modified home visit programme.

Una investigación dirigida por el Grupo de Investigación del Desarrollo Infantil en el Instituto de Investigación de Medicina Tropical, ha contribuido de manera significativa a comprender, por una parte, la importancia que tanto la nutrición temprana como el ambiente hogareño poseen para el desarrollo infantil de niños, y por otra parte, el impacto de la estimulación psicosocial para los niños desfavorecidos y/o desnutridos. La evidencia crítica ofrecida por este trabajo ha hecho que se le conceda mayor atención al desarrollo de la primera infancia en el trabajo y las políticas de agencias como el Banco Mundial, la Organización Mundial de la Salud (OMS) y el Fondo de las Naciones Unidas para la Infancia (UNICEF). Este estudio trata de una investigación que documenta el impacto de la desnutrición en el desarrollo de niños, y por primera vez demuestra los beneficios y la necesidad de la estimulación psicosocial para favorecer el desarrollo. La investigación subsiguiente fue decisiva para establecer la importancia del retraso del crecimiento linear (RCL) como un factor de riesgo para el desarrollo del niño pobre. Un estudio de veintidós años sobre niños con retraso en el crecimiento ha demostrado los beneficios hasta llegar a la adultez, en áreas como la educación, la salud mental y la reducción del comportamiento violento, a partir de un programa de visita a hogares de la primera infancia, que trabaja con las madres para promover el desarrollo de sus hijos.

Morning glory as a powerful model in ecological genomics: tracing adaptation through both natural and artificial selection.

Many diverse questions in ecology and evolution have been addressed using species belonging to the genus Ipomoea, commonly referred to as the morning glory genus. Ipomoea exhibits a wide range of diversity in floral color, growth form, mating system and tolerance to environmental factors, both within and among species, and as such has been a focal group of many investigations in the last 80 years. In this review, we highlight recent work to which Ipomoea species have contributed-from studies of the mating system, molecular evolution, plant-herbivore and plant-parasite interactions to their impact on and importance to agriculture. Genomic resources for this group are currently under development, and given the breadth of studies and history of this group, combined with an expanding genetics toolkit, we argue that Ipomoea should provide the next model organism for ecological genomics.