Male Mating Rate Is Constrained by Seminal Fluid Availability in Bedbugs, Cimex lectularius

Sexual selection, differences in reproductive success between individuals, continues beyond acquiring a mating partner and affects ejaculate size and composition (sperm competition). Sperm and seminal fluid have very different roles in sperm competition but both components encompass production costs for the male. Theoretical models predict that males should spend ejaculate components prudently and differently for sperm and seminal fluid but empirical evidence for independent variation of sperm number and seminal fluid volume is scarce. It is also largely unknown how sperm and seminal fluid variation affect future mating rate. In bedbugs we developed a protocol to examine the role of seminal fluids in ejaculate allocation and its effect on future male mating rate. Using age-related changes in sperm and seminal fluid volume we estimated the lowest capacity at which mating activity started. We then showed that sexually active males allocate 12% of their sperm and 19% of their seminal fluid volume per mating and predicted that males would be depleted of seminal fluid but not of sperm. We tested (and confirmed) this prediction empirically. Finally, the slightly faster replenishment of seminal fluid compared to sperm did not outweigh the faster decrease during mating. Our results suggest that male mating rate can be constrained by the availability of seminal fluids. Our protocol might be applicable to a range of other organisms. We discuss the idea that economic considerations in sexual conflict research might benefit from distinguishing between costs and benefits that are ejaculate dose-dependent and those that are frequency-dependent on the mating rate per se

An assessment of randomized controlled trials (RCTs) for non-communicable diseases (NCDs): more and higher quality research is required in less developed countries

Research is crucial to implement evidence-based health interventions for control of non-communicable diseases (NCDs). This study aims to assess main features of randomized controlled trials (RCTs) for the control of NCDs, and to identify gaps in clinical research on NCDs between high-income and less developed countries. The study included 1177 RCTs in 82 Cochrane Systematic reviews (CSRs) and evaluated interventions for adults with hypertension, diabetes, stroke, or heart diseases. Multivariate logistic regression analyses were conducted to explore factors associated with risk of bias in the included RCTs. We found that 78.2% of RCTs of interventions for major NCDs recruited patients in high-income countries. The number of RCTs included in the CSRs was increasing over time, and the increasing speed was more noticeable for RCTs from middle-income countries. RCTs in less developed countries tended to be more recently published, less likely to be published in English, with smaller sample sizes, and at a higher risk of bias. In conclusion, there is still a lack of research evidence for control of NCDs in less developed countries. To brace for rising NCDs and avoid waste of scarce research resources, not only more but also higher quality clinical trials are required in low-and-middle-income countries

Parental influences on youths' career construction

Increasingly, scholars are urging that there should be a careful examination of the role of social relations, especially those between parents and children, on the professional development of youth. In this chapter, we first present the recent models and theoretical approaches (e.g., contextual action theory, social cognitive model, and the life design approach) that recognize the need to carefully consider the role that parents play in their children\u2019s career development. Next, the parental support role in their children\u2019s professional development is explored, in relation to socioeconomic circumstances. Poverty, unemployment, precariousness, and underemployment are becoming characteristic of the context even in the richest countries; thus today\u2019s parents find themselves playing their support role in their children\u2019s professional development within much more complex societies. Some parents, especially those with low socioeconomic status (SES), are pessimistic in their overall perception of the economy, and, despite being concerned about their children\u2019s future, may find it hard to plan for it; thus, they do not encourage their children and do not start interactions centered on the future with them. Adolescent career development is affected by two interdependent contextual family factors: (a) structural family variables and (b) process family variables (e.g., parents\u2019 aspirations, parental support, family interactions). As regards structural variables, we examined socioeconomic background and social class. In research across multiple cultures, youth from families of low SES and social class have been found to have more limited opportunities for career development and more difficulties in accessing educational and social opportunities. Social class is a more difficult structural variable to define than SES. It is characterized as a cultural, psychological, and subjective factor internalized by the individual which goes beyond income, upbringing, and education, and shapes the construction of the self. As regards contextual process family variables, we focused on parental support and family interactions. Across ethnic groups (e.g., African-Americans, Italian, North Americans, French), adolescents who report greater support and more positive interactions with their parents are more engaged in designing their school\u2013career future. Specifically, greater parental support and positive relationships between parents and children are associated with more career decision-making, vocational exploration, career self-efficacy beliefs, career adaptability, less irrational career beliefs, and a greater propensity to optimism and hope in youth. In addition, it is in the family that children begin to give meaning to the world of work and construct their idea of education and work and of their career lives. Lastly, in relation to the relevance of relationships between parents and their children for the latter\u2019s career development, in this chapter we discuss how to help parents to support the realization of their children\u2019s professional projects. Parents are a key source for enabling youth to achieve preventive goals related to career education. Specifically, we provide two examples of parent training programs that are aimed at promoting parental skills in supporting their children\u2019s career construction