Sex-biased dispersal is usually driven by a combination of inbreeding avoidance and intrasexual competition. Walker and Pusey show that dispersal decisions in chimpanzees are most influenced by ...inbreeding avoidance and kin cooperation, instead of competition.
Chimpanzees are important referential models for the study of life history in hominin evolution. Age at sexual maturity and first reproduction are key life history milestones that mark the diversion ...of energy from growth to reproduction and are essential in comparing life history trajectories between chimpanzees and humans. Yet, accurate information on ages at these milestones in wild chimpanzees is difficult to obtain because most females transfer before breeding. Precise age at first birth is only known from a relatively small number of non-dispersing individuals. Moreover, due to small sample sizes, the degree to which age at maturation milestones varies is unknown. Here we report maturation milestones and explore sources of variance for 36 wild female chimpanzees of known age, including eight dispersing females born in Gombe National Park, Tanzania. Using Kaplan-Meier survival analysis, including censored intervals, we find an average age of 11.5 years (range 8.5–13.9) at sexual maturity and 14.9 years (range 11.1–22.1) at first birth. These values exceed previously published averages for wild chimpanzees by one or more years. Even in this larger sample, age at first birth is likely underestimated due to the disproportionate number of non-dispersing females, which, on average, give birth two years earlier than dispersing females. Model selection using Cox Proportional Hazards models shows that age at sexual maturity is delayed in females orphaned before age eight years and those born to low-ranking mothers. Age at first birth is most delayed in dispersing females and those orphaned before age eight years. These data provide improved estimates of maturation milestones in a population of wild female chimpanzees and indicate the importance of maternal factors in development.
Dominance hierarchies are widespread in animal social groups and often have measureable effects on individual health and reproductive success. Dominance ranks are not static individual attributes, ...however, but instead are influenced by two independent processes: 1) changes in hierarchy membership and 2) successful challenges of higher-ranking individuals. Understanding which of these processes dominates the dynamics of rank trajectories can provide insights into fitness benefits of within-sex competition. This question has yet to be examined systematically in a wide range of taxa due to the scarcity of long-term data and a lack of appropriate methodologies for distinguishing between alternative causes of rank changes over time. Here, we expand on recent work and develop a new likelihood-based Elo rating method that facilitates the systematic assessment of rank dynamics in animal social groups, even when interaction data are sparse. We apply this method to characterize long-term rank trajectories in wild eastern chimpanzees (Pan troglodytes schweinfurthii) and find remarkable sex differences in rank dynamics, indicating that females queue for social status while males actively challenge each other to rise in rank. Further, our results suggest that natal females obtain a head start in the rank queue if they avoid dispersal, with potential fitness benefits.
Minority physicians are more likely than their counterparts to work in underserved communities and care for minority, poor, and uninsured patients, but much of this research has examined primary care ...physicians alone. Few have investigated whether non-primary care specialists of minority backgrounds are more likely to serve the underserved than nonminority specialists.
We examined whether underrepresented minority (URM) physicians from a wide variety of specialties are more likely than non-URM physicians to practice in underserved communities.
Using California Medical Board Physician Licensure Survey (2007) data for 48388 physicians, we geo-coded practice zip codes to medically underserved areas (MUAs) and primary care health professional shortage areas (HPSAs). Logistic regression models adjusting for age, gender, specialty, and other characteristics were used to explore associations with race, ethnicity, specialty, and designated underserved areas.
We found that African American, Latino, and Pacific Islanders were more likely to work in MUAs and HPSAs than were white physicians (adjusted odds ratio, 1.22-2.25; p < .05). Similar patterns of practice in MUAs and HPSAs by physician race and ethnicity were found when performing the analyses separately among primary care physicians and physicians in non-primary care specialties.
In summary, our study underscores the importance of underrepresented minority physicians in all specialties for the physician workforce needs of disadvantaged communities. To improve health care for underserved communities, continued efforts to increase physician diversity are essential.
Humans are distinguished from the other living apes in having larger brains and an unusual life history that combines high reproductive output with slow childhood growth and exceptional longevity. ...This suite of derived traits suggests major changes in energy expenditure and allocation in the human lineage, but direct measures of human and ape metabolism are needed to compare evolved energy strategies among hominoids. Here we used doubly labelled water measurements of total energy expenditure (TEE; kcal day(-1)) in humans, chimpanzees, bonobos, gorillas and orangutans to test the hypothesis that the human lineage has experienced an acceleration in metabolic rate, providing energy for larger brains and faster reproduction without sacrificing maintenance and longevity. In multivariate regressions including body size and physical activity, human TEE exceeded that of chimpanzees and bonobos, gorillas and orangutans by approximately 400, 635 and 820 kcal day(-1), respectively, readily accommodating the cost of humans' greater brain size and reproductive output. Much of the increase in TEE is attributable to humans' greater basal metabolic rate (kcal day(-1)), indicating increased organ metabolic activity. Humans also had the greatest body fat percentage. An increased metabolic rate, along with changes in energy allocation, was crucial in the evolution of human brain size and life history.
Primate energy expenditure and life history Pontzer, Herman; Raichlen, David A.; Gordon, Adam D. ...
Proceedings of the National Academy of Sciences - PNAS,
01/2014, Letnik:
111, Številka:
4
Journal Article
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Humans and other primates are distinct among placental mammals in having exceptionally slow rates of growth, reproduction, and aging. Primates’ slow life history schedules are generally thought to ...reflect an evolved strategy of allocating energy away from growth and reproduction and toward somatic investment, particularly to the development and maintenance of large brains. Here we examine an alternative explanation: that primates’ slow life histories reflect low total energy expenditure (TEE) (kilocalories per day) relative to other placental mammals. We compared doubly labeled water measurements of TEE among 17 primate species with similar measures for other placental mammals. We found that primates use remarkably little energy each day, expending on average only 50% of the energy expected for a placental mammal of similar mass. Such large differences in TEE are not easily explained by differences in physical activity, and instead appear to reflect systemic metabolic adaptation for low energy expenditures in primates. Indeed, comparisons of wild and captive primate populations indicate similar levels of energy expenditure. Broad interspecific comparisons of growth, reproduction, and maximum life span indicate that primates’ slow metabolic rates contribute to their characteristically slow life histories.
The need for primary care investment has never been greater. Nationally, primary care is in high demand and yet many factors make it difficult to increase the number of practicing primary health ...health care professionals, including salaries, educational debt, and practice redesign. These primary care workforce challenges are particularly acute in Delaware, which is the second smallest state by area, the sixth smallest by population, the third highest in per capita total health expenditures, and the 31st in health outcomes. As a family physician serving as Cabinet Secreatry for the Department of Health and Social Services, I faced a challenging fiscal environment my first year in office in which health care costs contributed to a budget shortfall.
Female competition in chimpanzees Pusey, Anne E.; Schroepfer-Walker, Kara
Philosophical transactions of the Royal Society of London. Series B. Biological sciences,
12/2013, Letnik:
368, Številka:
1631
Journal Article
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Female chimpanzees exhibit exceptionally slow rates of reproduction and raise their offspring without direct paternal care. Therefore, their reproductive success depends critically on long-term ...access to high-quality food resources over a long lifespan. Chimpanzee communities contain multiple adult males, multiple adult females and their offspring. Because males are philopatric and jointly defend the community range while most females transfer to new communities before breeding, adult females are typically surrounded by unrelated competitors. Communities are fission–fusion societies in which individuals spend time alone or in fluid subgroups, whose size depends mostly on the abundance and distribution of food. To varying extents in different populations, females avoid direct competition by foraging alone or in small groups in distinct, but overlapping core areas within the community range to which they show high fidelity. Although rates of aggression are low, females compete for space and access to food. High rank correlates with high reproductive success, and high-ranking females win direct contests for food and gain preferential access to resource-rich sites. Females are aggressive to immigrant females and even kill the newborn infants of community members. The intensity of such aggression correlates with population density. These patterns are compared to those in other species, including humans.
U.S. suicide rates have risen every year over the past two decades with self-directed firearm use as the method accounting for the highest proportion of deaths. This pattern is particularly ...pronounced among veterans and members of the U.S. Armed Forces. The numerical burden of firearm-related suicide accompanied by characteristics of self-directed firearm injury have motivated the development of lethal means safety initiatives focused on firearms. Simultaneously, research has sought to characterize patterns of firearm ownership and use among veterans as well as optimal strategies for clinicians to deliver suicide prevention messages to firearm owners. Increasingly, findings from research have been understood as cultural factors that warrant greater attention to improve the quality of lethal means counseling. Here, we review and interpret selected research on cultural aspects of firearm ownership and suggest that cultural differences between health care practitioners and firearm owners may result in health care practitioners delivering clinical interventions that are broadly divergent from perspectives within the cultural frameworks of firearm owners. We follow by organizing these cultural factors into existing frameworks of cultural competency training as a basis for developing curriculum for health care practitioners to improve clinical care.
BACKGROUND:The burden of informal caregiving is significant and well-documented, yet the evidence is mixed as to whether being a caregiver presents an additional barrier to receiving recommended ...preventive care.
OBJECTIVES:To determine whether (1) caregivers compared with noncaregivers were less likely to receive preventive health services; and (2) higher intensity caregivers were less likely to receive preventive health services than lower intensity caregivers.
RESEARCH DESIGN, SUBJECTS, AND MEASURES:Data were from a telephone survey of Latino and African American adults 50 years or older in South Los Angeles (n=702). Outcomes were flu vaccination, pneumococcal vaccination, and colorectal cancer screening. Logistic regression models adjusted for predisposing, enabling, and need factors according to the Andersen Model of Access to Health Care for Low-income Populations.
RESULTS:Caregiver type (eg, adult child, nonrelated) was associated with varying odds of receiving a preventive service. Caregivers had lower odds than noncaregivers of receiving preventive services although odds of receiving a flu vaccination improved slightly for caregivers of persons with memory loss compared with other caregivers. More weekly caregiving hours was associated with higher odds of receiving flu vaccination (adjusted odds ratios, 1.1; 95% confidence interval=1.0, 1.1) or colorectal cancer screening (adjusted odds ratios, 1.1; 95% confidence interval=1.0, 1.1). Caregivers and noncaregivers age 65 and older or with chronic conditions were more likely to receive vaccinations.
CONCLUSIONS:Preventive service use was influenced by characteristics of the caregiving situation. An opportunity may exist to leverage care recipients’ ongoing contact with health care providers to increase caregivers’ own access to preventive services.
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