• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 23
  • 5
  • 3
  • 3
  • Tagged with
  • 44
  • 44
  • 44
  • 11
  • 9
  • 7
  • 6
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The K-SF-42

Figueredo, Aurelio José, Garcia, Rafael Antonio, Menke, J. Michael, Jacobs, W. Jake, Gladden, Paul Robert, Bianchi, JeanMarie, Patch, Emily Anne, Beck, Connie J. A., Kavanagh, Phillip S., Sotomayor-Peterson, Marcela, Jiang, Yunfan, Li, Norman P. 01 1900 (has links)
The purpose of the present article is to propose an alternative short form for the 199-item Arizona Life History Battery (ALHB), which we are calling the K-SF-42, as it contains 42 items as compared with the 20 items of the Mini-K, the short form that has been in greatest use for the past decade. These 42 items were selected from the ALHB, unlike those of the Mini-K, making direct comparisons of the relative psychometric performance of the two alternative short forms a valid and instructive exercise. A series of secondary data analyses were performed upon a recently completed five-nation cross-cultural survey, which was originally designed to assess the role of life history strategy in the etiology of interpersonal aggression. Only data from the ALHB that were collected in all five cross-cultural replications were used for the present analyses. The single immediate objective of this secondary data analysis was producing the K-SF-42 such that it would perform optimally across all five cultures sampled, and perhaps even generalize well to other modern industrial societies not currently sampled as a result of the geographic breadth of those included in the present study. A novel method, based on the use of the Cross-Sample Geometric Mean as a criterion for item selection, was used for generating such a cross-culturally valid short form.
2

Validating Body Condition Indices As Indicators Of Individual Quality: Does Condition Explain Intraspecific Variation In Reproductive Success And Survival Among Crimson Finches (Neochmia Phaeton)?

Milenkaya, Olga 05 November 2013 (has links)
Body condition is expected to reflect individual quality because high quality individuals should be better at acquiring and using resources, resulting in higher fitness. However, the hypothesis that condition indices are meaningful indicators of individual quality has been questioned. I monitored a population of crimson finches (Neochmia phaeton) for reproductive success and survival over four breeding seasons. My study population is well suited for this research because individuals forage in common areas and do not hold territories such that variation in condition between individuals is not confounded by differences in habitat quality. Because little is known about crimson finches in the wild, I first describe their breeding biology and life-history traits (Chapter I). Next, I sampled them for commonly used condition indices including mass adjusted for body size, muscle and fat scores, packed cell volume, hemoglobin concentration, total plasma protein, and heterophil to lymphocyte ratio. I describe the variation in these indices and find that many vary by sex and breeding stage, and to a lesser extent by year, age and time of day, concluding that these covariates need to be controlled for when examining intraspecific variation in condition (Chapter II). If condition indices reflect inherent individual quality, then condition indices should be (a) repeatable within individuals, and (b) predictors of realized fitness. I test these two predictions in Chapters III and IV, respectively, and I find that condition indices are repeatable within individuals over short, but not long, time periods and that some indices predict reproductive success, while others do not, and that none predict survival. Both findings only partially support the hypothesis that condition indices are meaningful indicators of individual quality, raising concerns over this common interpretation. In Chapter V, I glean insights from the ecological and poultry science literature and discuss further complications with the use of condition indices as proxies for individual quality and fitness. I conclude that condition indices indicate how well an individual is currently acquiring resources as well as its likely physiological state over the next few months, but that they do not reflect individual quality and are not reliable proxies for fitness. / Ph. D.
3

Substance, History, and Politics

Black, Candace J., Figueredo, Aurelio José, Jacobs, W. Jake 01 1900 (has links)
The aim of this article is to examine the relations between two approaches to the measurement of life history (LH) strategies: A traditional approach, termed here the biodemographic approach, measures developmental characteristics like birthweight, gestation length, interbirth intervals, pubertal timing, and sexual debut, and a psychological approach measures a suite of cognitive and behavioral traits such as altruism, sociosexual orientation, personality, mutualism, familial relationships, and religiosity. The biodemographic approach also tends not to invoke latent variables, whereas the psychological approach typically relies heavily upon them. Although a large body of literature supports both approaches, they are largely separate. This review examines the history and relations between biodemographic and psychological measures of LH, which remain murky at best. In doing so, we consider basic questions about the nature of LH strategies: What constitutes LH strategy (or perhaps more importantly, what does not constitute LH strategy)? What is gained or lost by including psychological measures in LH research? Must these measures remain independent or should they be used in conjunction as complementary tools to test tenets of LH theory? Although definitive answers will linger, we hope to catalyze an explicit discussion among LH researchers and to provoke novel research avenues that combine the strengths each approach brings to this burgeoning field.
4

The ecology of ageing in albatrosses

Froy, Hannah January 2014 (has links)
Age-related variation in demographic rates has significant consequences for population and evolutionary dynamics, and understanding the processes driving such variation is therefore an important aspect of evolutionary ecology. Reproductive performance may vary over the lifetime of an individual, and this may be the result of both variations in reproductive effort and changes in individual competency. For example, increasing experience is likely to have beneficial effects on reproduction during early life, and senescence, or declines in physiological function, may have negative impacts on the performance of older individuals. The rate at which these changes occur can vary dramatically between species, and even between individuals of the same species. However, understanding the causes and consequences of this variation in the rate of ageing is not always straightforward. As well as the individual-level processes described, the phenotypic composition of successive age classes will contribute to age-related variation observed at the population level. Abrupt changes in performance, such as the poor performance of first time breeders, may be obscured if individuals vary in their age at first reproduction. Population-level patterns may also be influenced by selection; for example, the selective disappearance of low quality individuals from older age classes may mask senescent declines in the performance of longer-lived individuals. Moreover, the physiological mechanisms that underpin within-individual changes in performance are not well understood. Unravelling the drivers of such age-related variation requires longitudinal data, following individuals throughout their lives, which presents challenges for the study of natural populations. Albatrosses are among the longest lived vertebrates. In this thesis, I use data from three species of albatross breeding at Bird Island, South Georgia (54°00’S, 38°03’W) to explore age-related variation. Focusing primarily on the wandering albatross, Diomedea exulans, I characterise the relationship between age and various reproductive traits, and decompose the population-level patterns to reveal effects of experience, senescence and terminal effects across the reproductive lifespan of individuals. I then consider foraging behaviour as a proximate driver of changes in reproductive performance in this species. Using tracking data collected over a 20 year period, I find limited evidence for age-related variation in foraging trips taken throughout the breeding cycle. Going one step further, I explore telomere dynamics in the wandering albatross, examining the potential for telomere length to act as a physiological marker of individual state. Finally, I move on to a species comparison, incorporating data from the black-browed (Thalassarche melanophris) and grey-headed albatross (Thalassarche chrysostoma). I compare the population- and individual-level ageing patterns of these three closely related species, and consider these in light of their differing life history strategies.
5

I'd Give My Right Kidney to Be Altruistic: The Social Biogeography of Altruism in the United States of America

Garcia, Rafael Antonio, Garcia, Rafael Antonio January 2017 (has links)
The purpose of this dissertation is to model biosocial determinants of group-directed altruistic behavior – exploring the nomological net around it. To do this a study will be presented to determine existing associations among various biological and social predictors and test a life-history-derived causal cascade using a partially exploratory and partially confirmatory statistical technique called Sequential Canonical Analysis to ultimately predict living-donor, non-directed kidney donations (NDKD). Toward that end, some important methodological considerations first need to be discussed. The first consideration revolves around the level of analysis and how this frames the cascade model and its interpretation. Following a general discussion, an exercise in some of the general principles is provided – investigating the higher-order factor structure of the Big-5 personality constructs across two levels of analysis. The second consideration is the use of unit-weighted factor scores and their appropriateness. Following the theoretical discussion, a demonstration is provided – deriving an estimate of genetic relatedness from a set of heterogeneous data sets. Once the methodological considerations have been discussed, the primary cascade model is presented in two parts: 1) the measurement model – operationalizing the measures incorporated into 2) the structural model – testing the proposed causal cascade using Sequential Canonical Analysis. A discussion follows in which the results are summarized, limitations are articulated, and further research directions are explored.
6

Effortful Control Development In The Face Of Harshness and Unpredictability

Warren, Shannon M., Warren, Shannon M. January 2017 (has links)
Through the life history theory perspective, this paper seeks to demonstrate how early adversity shapes the development of effortful control in ways that aim to best match the individual to the proximal environment toward ultimate goals despite trade-offs related to social, academic, and later health outcomes. Investigation linking early life harshness (i.e., cues of extrinsic morbidity-mortality; Ellis et al., 2009) and unpredictability (i.e., stochastic changes in environmental conditions; Ellis et al., 2009) to the development of self-regulation could facilitate a more nuanced understanding of early environmental effects on development. The current study investigates early environmental harshness and unpredictability as unique predictors for a self-regulation construct, effortful control. It was hypothesized that early life harshness and unpredictability would uniquely and negatively predict effortful control among preschoolers. While there was no evidence that cues of unpredictability predicted effortful control, cues of harshness, specifically neighborhood harshness, did statistically significantly predict effortful control in the direction expected. This appears to be the first study to explicitly investigate effortful control development in early childhood within the harshness and unpredictability framework.
7

Reproductive tactics in butterflies – the adaptive significance of monandry versus polyandry in <em>Pieris napi</em>

Välimäki, P. (Panu) 15 May 2007 (has links)
Abstract Females may either mate with one (monandry) or several (polyandry) males during a single breeding season. The polyandrous mating system has prompted numerous studies since the recognition of a widespread occurrence of mixed paternity among animals. Consequently, the benefits of polyandry have become well-established, and the female role in sexual selection upgraded. Females may gain both material and genetic benefits from multiple mating. Hence, the occurrence of polyandry is understandable, whereas monandry remains an evolutionary puzzle especially among species with male nutrient provisioning. I studied both the life history variation among female mating tactics and the adaptive significance of monandry in varying environmental conditions in the green-veined white butterfly [Pieris napi, (L. 1758)], which is a predominantly polyandrous species with nuptial feeding. I used a combination of explicit laboratory experiments and field studies. My results show that monandry and degrees of polyandry are distinct strategies with life history differences reaching beyond mating frequencies. Polyandry corresponded with a higher lifetime fecundity than monandry in P. napi. Polyandry was, however, associated with relatively low fecundity during the early days of reproduction. Thus, monandry is beneficial if time for reproduction is limited severely enough or other female traits or behaviours associated with polyandry are traded off against longevity. Due to temporal variation in reproductive rate among mating tactics, offspring of polyandrous females have less time to complete development. Accordingly, polyandrous females developed at a faster rate as larvae than monandrous ones under optimal conditions. Despite growth rate variation, monandrous females were more likely to contribute to additional summer generation in conditions that allow production of only a partial second generation, and thus monandry is favoured under these conditions. Genetic variation in female mating tactics will not only prevail if environmental conditions do not allow all individuals to contribute evenly to the directly breeding generation in bivoltine populations, but also if even the production of a single generation per year is time-limited. A general conclusion would be that seasonality and unpredictability of fitness in the wild drives the evolution of optimal female mating tactics and promotes the maintenance genetic variation in mating frequencies, regardless of the direct benefits of nuptial feeding. Even if a high degree of polyandry would be the most profitable mating tactic in an average year, strong annual variation in weather conditions and the duration of summer may create possibilities for a temporally fluctuating selection that promotes a co-existence of different mating tactics because variance of fitness is likely increase with an increasing mating frequency.
8

Evolution, Ecology, and Disparities: Constructing Stature, Immune Functioning, and Reproduction in Brazilian Quilombo, and United States, Women

Rivara, Anna C. 14 April 2017 (has links)
The purpose of this dissertation is to test how growth, reproduction, and immune functioning interact in two populations of adult women residing in vastly different socio-economic and ecological environments, the Kalunga quilombo in Brazil, and the United States of America. The presence of life history trade-offs was tested to determine how the different envirnonments, and socio-ecological contexts of the populations were creating differential risks for health and reproductive outcomes, and life history trade-offs. I hypothesized that the Kalunga people, living in very difficult and harsh conditions, would experience greater amounts of, and more severe, life history trade-offs than the U.S. women. I also hypothesized that in both populations, syndemic interactions between health outcomes, and the larger macro-social conditions, would influence stature, immune functioning, and reproduction. Additionally, these syndemic interactions would perpetuate poor health and reproductive outcomes within the entire Kalunga population, and portions of the U.S. population. I collaborated with the University of Brasilia to collect data adult women from in the Kalunga quilombo in Goiás State, Brazil (n=38) via semi-structured interviews in 2016. In addition, these data were compiled with reproductive, demographic, anthropometric, biological, and socio-economic data collected from adult Kalunga women in 2015 by the University of Brasilia’s Department of Genetics and Morphology. Demographic, anthropometric, biological, and socio-economic data recorded in the National Health and Nutrition Examination Survey (NHANES) 2005-2006 from adult U.S. women was also analyzed. Life history traits were measured through stature (cm), Immunoglobulin E (IgE; kU/l), and reproductive variables (fertility, and reproductive ages) for both populations. My results demonstrated that life history trade-offs impact diverse populations. I found evidence to support life history trade-offs occurred between stature and fertility, and stature and reproductive ages, in both populations. However, my results also indicated that the socio-economic, and ecological, conditions of both populations heavily influenced stature and reproduction in the women. Life history trade-offs were not observable between immune functioning and fertility in the Kalunga population, and not readily evident in the U.S. sample. The positive associations between IgE and fertility in the U.S. women indicate that while life history trade-offs may be suggested, other biocultural variables including: low income, ethnicity, education, and body size, are stronger influences on immune functioning, and fertility, in the U.S. women. Though the Kalunga women had a history of infectious and parasitic diseases, and lived in conditions of poor sanitation and poverty, they had multiple ways of mitigating the stresses of their everyday life. The shared socio-ecological conditions of their community decreased the deprivations they experienced, reduced the disabilities they felt from their health statuses, and was reflected in relative homogeneity of their lived experience. In contrast, the U.S. population was dictated by disparities. Poor health and reproductive outcomes were concentrated disproportionately in low-income, less educated, and/or minority ethnicity status, women. The findings of this dissertation have important implications for applied anthropology and the study of life history theory. My results demonstrate that Western lifestyles must be considered as instigators of life history trade-offs, and life history scholarship in humans must also focus on populations living in these conditions. Additionally, the secular changes resulting in lowered ages of menarche in U.S. women could lead to future poor health outcomes. As the Kalunga transitions into a more Western lifestyle, they are at risk for disparities within their population. It is imperative for applied anthropologists to be engaged in addressing the immune, nutritional, and psychosocial stressors within populations that perpetuate disparities, and instigate and/or exacerbate life history trade-offs.
9

The Biological Impact of Developmental Stress in the Past: Correlations between Growth Disruptions and Mortality Risk in Bioarchaeology

Cheverko, Colleen Mary 27 December 2018 (has links)
No description available.
10

The Life History Narrative: How Early Events and Psychological Processes Relate to Biodemographic Measures of Life History

Black, Candace Jasmine January 2016 (has links)
The aim of this project is to examine the relationships between two approaches to the measurement of life history strategies. The traditional method, termed here the biodemographic approach, measures developmental characteristics like birthweight, gestation length, inter-birth intervals, pubertal timing, and sexual debut. The alternative method under exploration, termed here the psychological approach, measures a suite of cognitive and behavioral traits such as altruism, sociosexual orientation, personality, mutualism, familial relationships, and religiosity. Although both approaches are supported by a large body of literature, they remain relatively segregated. This study draws inspiration from both views, integrating measures that assess developmental milestones, including birthweight, prematurity, pubertal timing, and onset of sexual behavior, as well as psychological life history measures such as the Mini-K and a personality inventory. Drawing on previous theoretical work on the fundamental dimensions of environmental risk, these measures are tested in conjunction with several scales assessing the stability of early environmental conditions, including both "event-based" measures that are defined with an external referent, and measures of internal schemata, or the predicted psychological sequelae of early events. The data are tested in a three-part sequence, beginning with the measurement models under investigation, proceeding to an exploratory analysis of the causal network, and finishing with a cross-validation of the structural model on a new sample. The findings point to exciting new directions for future researchers who seek to integrate the two perspectives.

Page generated in 0.1157 seconds