519 research outputs found

    Race in the Life Sciences: An Empirical Assessment, 1950-2000

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    The mainstream narrative regarding the evolution of race as an idea in the scientific community is that biological understandings of race dominated throughout the nineteenth and twentieth centuries up until World War II, after which a social constructionist approach is thought to have taken hold. Many believe that the horrific outcomes of the most notorious applications of biological race—eugenics and the Holocaust—moved scientists away from thinking that race reflects inherent differences and toward an understanding that race is a largely social, cultural, and political phenomenon. This understanding of the evolution of race as a scientific idea informed the way that many areas of law conceptualize human equality, including civil rights, human rights, and constitutional law. This Article provides one of the first large-scale empirical assessments of publications in peer-reviewed biomedical and life science journals to examine whether biological theories of race actually lost credibility in the life sciences after World War II. We find that biological theories of race transformed yet persisted in the dominant academic discourse up through modern times—a finding that contradicts the central narrative that the life sciences became “color-blind” or “post-racial” several decades ago. The continued salience of biological race in the life sciences suggests that more attention needs to be paid to the questionable assumptions driving this research on biological race and its potential spillover effects, i.e., how persisting claims of biological race in the scientific literature might reconstitute its significance in law and society in a manner that may be harmful to racial minorities

    COGNITIVE PERFORMANCE AND THE EVOLUTION OF MULTIPLE BEHAVIORAL DISPLAY TRAITS

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    Males of many species have complex behavioral sexual displays and it is possible that these displays indicate aspects about male quality because of their relationship with cognitive ability. However, the relationship between behavioral display traits, cognitive ability, and reproductive success has received little attention. Satin bowerbirds, Ptilonorhynchus violaceus, are an excellent species for studying this relationship because their complex male courtship suggests a selective advantage to individuals with superior cognitive abilities. Here I show that cognitive performance can have important effects on mating success and the quality of behavioral displays. First, I present males with two novel problem solving tests and find that males who are better at solving these problems have higher mating success, establishing a link between male cognitive ability and sexual attractiveness. Second, I add four additional cognitive tests to expand the diversity of cognitive abilities tested and construct two measures of general cognitive ability using these data: the scores from an analysis that best explains covariation among performance on the different cognitive tests (g), and the average rank score on these cognitive tests ("IQ"). I show that these measures of general cognitive ability, as well as the majority of the independent cognitive tests, are positively associated with mating success. Third, I construct a different composite measure of male cognitive ability using an analysis that determines the combination of cognitive traits that make males most successful in attracting females (f). I show that this measure is significantly associated with my measures of general cognitive ability, suggesting that evolution of cognitive ability in bowerbirds is possible if there is sufficient heritability. I construct three different aggregate measures of male display quality (produced from four behavioral display traits) and find that they are all associated with f and with mating success. Finally, I show some support for the hypothesis that separate display traits may indicate different aspects of male cognitive ability. These results suggest that behavioral display traits may have a special role in sexual selection because of their connection to cognitive ability. Overall, this research highlights the importance of considering the interrelationship between cognitive ability and sexual selection

    Stochastic population growth in spatially heterogeneous environments

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    Classical ecological theory predicts that environmental stochasticity increases extinction risk by reducing the average per-capita growth rate of populations. To understand the interactive effects of environmental stochasticity, spatial heterogeneity, and dispersal on population growth, we study the following model for population abundances in nn patches: the conditional law of Xt+dtX_{t+dt} given Xt=xX_t=x is such that when dtdt is small the conditional mean of Xt+dtiXtiX_{t+dt}^i-X_t^i is approximately [xiμi+j(xjDjixiDij)]dt[x^i\mu_i+\sum_j(x^j D_{ji}-x^i D_{ij})]dt, where XtiX_t^i and μi\mu_i are the abundance and per capita growth rate in the ii-th patch respectivly, and DijD_{ij} is the dispersal rate from the ii-th to the jj-th patch, and the conditional covariance of Xt+dtiXtiX_{t+dt}^i-X_t^i and Xt+dtjXtjX_{t+dt}^j-X_t^j is approximately xixjσijdtx^i x^j \sigma_{ij}dt. We show for such a spatially extended population that if St=(Xt1+...+Xtn)S_t=(X_t^1+...+X_t^n) is the total population abundance, then Yt=Xt/StY_t=X_t/S_t, the vector of patch proportions, converges in law to a random vector YY_\infty as tt\to\infty, and the stochastic growth rate limtt1logSt\lim_{t\to\infty}t^{-1}\log S_t equals the space-time average per-capita growth rate \sum_i\mu_i\E[Y_\infty^i] experienced by the population minus half of the space-time average temporal variation \E[\sum_{i,j}\sigma_{ij}Y_\infty^i Y_\infty^j] experienced by the population. We derive analytic results for the law of YY_\infty, find which choice of the dispersal mechanism DD produces an optimal stochastic growth rate for a freely dispersing population, and investigate the effect on the stochastic growth rate of constraints on dispersal rates. Our results provide fundamental insights into "ideal free" movement in the face of uncertainty, the persistence of coupled sink populations, the evolution of dispersal rates, and the single large or several small (SLOSS) debate in conservation biology.Comment: 47 pages, 4 figure

    Summability of alterations of convergent series

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    The effect of splitting, rearrangement, and grouping series alterations on the summability of a convergent series by ℓ−ℓ and cs−cs matrix methods is studied. Conditions are determined that guarantee the existence of alterations that are transformed into divergent series and into series with preassigned sums

    Relationships between two forms of social position and peer affiliations: patterns across the transition from elementary to middle school

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    Contradictions regarding social relations currently exist within the literature, specifically with respect to the nature, causes, and correlates of social position. These contradictions stem from conceptual and methodological inconsistencies as well as developmental differences in certain traits and constructs. Building from these diverse research frameworks, the current study is designed to clarify relationships among relevant constructs in order to facilitate future research and the development of practical interventions. The current study addressed the contradictions in the literature by investigating the relationship between several aspects of social functioning including social position (social preference and social prominence) and peer affiliations across the transition from elementary to middle school. Peer interpersonal ratings in both fifth and sixth grades were available for 566 students; teacher ratings were also collected for those with consent for participation (399 students in fifth grade; 417 students in sixth grade). Results highlighted the complex nature of social relationships during early middle school when social networks are fluid. First, the social position constructs of social preference and social prominence were found to diverge for boys across the transition, but to stay constant for girls. Next, aggression was found to be negatively correlated with social preference and positively correlated with social prominence, with some decrease in the strength and significance of these correlations across the transition to middle school, especially for social prominence. Gender effects were apparent and suggested that girls' use of aggression at the beginning of middle school is complex; these results are considered in the context of ethnographic research. Finally, the social position constructs were found to be minimally related to the characteristics of peer affiliates, with the most consistent relationships between individual social prominence and peer popularity. This study supports the development and importance of social interventions at the beginning of middle school when social hierarchies are developing and social structures are fluid. Furthermore, it highlights the difficulties involved in conducting a static assessment of a dynamic social network

    El Cenote: a succession of eternities

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    Keagy, Rini Y.. (2021). El Cenote: a succession of eternities. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/223262

    Sperm-mediated Effects of Predation Risk on Reproduction in Male Threespined Sticklebacks

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    Threespined sticklebacks, Gasterosteus aculeatus, exhibit male-only parental care, but will decrease paternal care if exposed to predators while given care or if their mate has had prior experiences with predators. The offspring will experience lasting effects based on the experience of their parents (behavior-mediated transgenerational plasticity). While other studies have concluded that male exposure to predators prior to fertilization (sperm-mediated transgenerational plasticity) impacts offspring, whether sperm-mediated effects exist in sticklebacks, and for how many generations the effects persist is unknown. Courtship trials with both predator exposed and predator unexposed females with six male treatment groups shows significant impact of maternal grandfather predation exposure, suggesting that daughters of predator-exposed fathers are passing down cues to their sons

    Sensory Communication

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    Contains table of contents on Section 2, an introduction, reports on eleven research projects and a list of publications.National Institutes of Health Grant 5 R01 DC00117National Institutes of Health Grant 5 R01 DC00270National Institutes of Health Contract 2 P01 DC00361National Institutes of Health Grant 5 R01 DC00100National Institutes of Health Contract 7 R29 DC00428National Institutes of Health Grant 2 R01 DC00126U.S. Air Force - Office of Scientific Research Grant AFOSR 90-0200U.S. Navy - Office of Naval Research Grant N00014-90-J-1935National Institutes of Health Grant 5 R29 DC00625U.S. Navy - Office of Naval Research Grant N00014-91-J-1454U.S. Navy - Office of Naval Research Grant N00014-92-J-181
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