This paper proposes a tractable model to study the equilibrium diversity of technological progress and shows that equilibrium technological progress may exhibit too little diversity (too much conformity), in particular, foregoing socially bene…cial investments in “alternative”technologies that will be used at some point in the future. The presence of future innovations that will replace current...

This cross-sectional study analyzes the relationship between gradients of social inequalities and the household environment and health and nutritional conditions among 2,001 preschool children in ten counties (municipalities) in the State of Bahia, Brazil. The analysis used multinomial multivariate logistic regression. Children in the middle and lower tertiles on the poverty scale had significa...

Social comparison can elicit emotions such as envy, which can affect social interactions. The emergence and development of such social emotions through ontogeny, and their influence on social interaction, are unknown. We tested 182 children from 7 to 13 years of age with a novel monetary reward-and-punishment task measuring envy and Schadenfreude (i.e., gloating or taking delight in someone els...

Recent studies by our group and others have demonstrated that growth hormone (GH) is produced endogenously within the hippocampal formation, a brain structure associated with learning and aspects of emotional experience. Here, we demonstrate that this endogenously produced GH is modulated by age and sex differences and the presence of estrogen. GH mRNA levels were higher in females than males, ...

Horns or hornlike structures in beetles have become an increasingly popular study system for exploring the evolution and development of secondary sexual trait diversity and sexual dimorphisms. The horns of adult beetles originate during a rapid growth phase during the prepupal stage of larval development, and differential activation of growth during this time is either implicitly or explicitly ...

The song nuclei of the male zebra finch (Poephila guttata) contain larger neurons than those of the female. This gender difference arises after hatching as a result of cell atrophy in the female and cell growth in the male. Implantation of estrogen in female chicks induces masculine differentiation of neurons in their song nuclei. The effects of estrogen on neuron size decline steeply after pos...

There are approximately 10,000 births per year in the county of Oxfordshire in the UK, which is one of the two European sites for the International Fetal and Newborn Growth Consortium for the 21(st) Century (INTERGROWTH-21(st) ) Project. The samples for both components of the project--the Fetal Growth Longitudinal Study (FGLS) and Newborn Cross-Sectional Study (NCSS)--were drawn from the John R...

or results directly preceding dialysis. Ellam and his colleagues have to be congratulated for a thorough effort highlighting gender differences in nutritional burden by level of eGFR. Their study raises a number of important questions that should be investigated further, such as longitudinal changes in nutritional needs by gender and the important role of gender and societal context on how rena...

Adult sex ratio (ASR) is a central concept in population biology and a key factor in sexual selection, but why do most demographic models ignore sex biases? Vital rates often vary between the sexes and across life history, but their relative contributions to ASR variation remain poorly understood-an essential step to evaluate sex ratio theories in the wild and inform conservation. Here, we comb...

BACKGROUND Largely due to methodological problems in existing studies, issues concerning causal directions and confounding factors, such as the stability effect, remain to be clarified in the relations among aggression, peer relationships, and psychological adjustment. The purpose of this longitudinal study was to examine (a) reciprocal direct and indirect effects among aggression, peer relatio...