Doctor of Philosophy

dissertationSocial dominance is the most important known behavior to reproductive success of males across the animal kingdom. A high social dominance rank is usually gained by physical competition or signals displaying competitor quality. Despite its importance in shaping the diversity seen in the animal kingdom, little is known about specific traits that promote high competitive ability within an individual. In this dissertation, I begin to elucidate some of the behavioral physiology underpinning competitive ability in the premier mammalian model system, the house mice (Mus musculus). House mice are ideally suited for this study because of a well-characterized natural history demonstrating that dominant males gain ~90% of all fitness, while still having to perform many other behaviors, such as foraging. In this dissertation, I provide an overview of the some hypothesized constraints on the evolution of competitive ability and phenotypic trade-offs with other important life-history traits. Second, I describe an experiment that investigated multiple traits at several levels of biological for their possible influence on competitive ability. I demonstrate that competitive ability is heritable, moderately influenced by relative body mass, and negatively influence by litter sex ratio. No effect of litter size, relative age, or placement order was seen. Third, I demonstrate that aggression and competitive ability are distinct phenomena in iv this system. Next, I demonstrate that primary signaling pheromone of house mice, major urinary proteins, do not advertise rank but are responsive to social experience. Finally, I switch clades and demonstrate that relative brain size in primates is positively associated with intensity of male-male competition. Collectively, this project demonstrates that competitive ability is an extremely complicated phenotype and merits a great deal more study

An indentured servant: The impact of green card waiting time on the life of highly skilled Indian immigrants in the United States of America

Highlighting the archaic immigration system in the United States of America (US), the present study demonstrates for the first time the impact of green card waiting time on the work and family life of Indian immigrants living in the US. Our present findings show that 93.4% of our participants are very concerned about the estimated green card waiting time in the US. We find 70% of the total participants are seriously thinking at the present time about emigrating to a more visa-friendly country. Also, 30% of the participants have already applied for permanent residency in a visa friendly country and 9% of the participants have already obtained a permanent residency in a more visa-friendly country. Based on these turnover intentions, we estimate the potential direct costs to American organizations due to the green card waiting time to be in the range of $19,303,200,000 -$54,261,724,160. Furthermore, our quantitative results show that the delay in receiving a green card is negatively affecting the work and family/nonwork life of Indian immigrants in the US. These critical issues are in turn causing health issues such as constant fear of unknown (uncertainty and feeling stuck issues due to green card backlog), stress, frustration and chronic health issues. Overall, in addition to the direct losses, the work and family issues caused due to the green card waiting time could result in indirect losses to organizations. We hope that the present findings may be useful to American policy makers and organizational leaders as further decisions are made regarding the American immigration system. In particular, we hope these findings will help to illustrate many serious implications associated with the green card delays and other visa-related proposed policy changes on immigrants, and their spouses, families, and communities.https://scholar.utc.edu/iopsy/1002/thumbnail.jp

Impact of spousal work restrictions and number of dependents on expatriates’ work life and overall life satisfaction

Purpose Our understanding of the challenges and the broader role of spouses of expatriates is extremely limited. The purpose of the study was to examine the impact of spousal work restrictions and number of dependents on expatriates’ work life and overall life satisfaction using qualitative and quantitative analyses Design Data were collected from 416 Indian informational technology professionals working in USA. Hypothesized conditional process models were analyzed using the PROCESS tools. Findings Spousal work restrictions and number of dependents created complications in personal life of expatriates, which interfered with their work life resulting in lower overall life satisfaction. We identified six core classes of challenges faced by spouses of expatriates: financial issues, frustration, loss of respect/low confidence, boredom, social isolation, and domestic tension. Older expatriates were able to better manage the responsibilities associated with number of dependents. More importantly, unlike adjustment, the issues associated with spouse work restrictions did not seem to improve with age or length of time in the USA. Originality Although media outlets have from time to time brought to light the issues faced by spouses of expatriates, the present study provides more credible and complete findings by conducting a qualitative and quantitative research study. To our knowledge this is the first study that has investigated the complications experienced by expatriates’ due to the work restriction (more specifically, visa related) issues faced by the spouses of these expatriates. Our mixed method approach also helps to provide a more comprehensive picture of these complications.https://scholar.utc.edu/iopsy/1001/thumbnail.jp

Transcriptomes of parents identify parenting strategies and sexual conflict in a subsocial beetle

This work was funded by UK NERC grants to M.G.R. and A.J.M. an NERC studentship to D.J.P. the University of Georgia and a US NSF grant to A.J.M. and M.G.R.Parenting in the burying beetle Nicrophorus vespilloides is complex and, unusually, the sex and number of parents that can be present is flexible. Such flexibility is expected to involve specialized behaviour by the two sexes under biparental conditions. Here, we show that offspring fare equally well regardless of the sex or number of parents present. Comparing transcriptomes, we find a largely overlapping set of differentially expressed genes in both uniparental and biparental females and in uniparental males including vitellogenin, associated with reproduction, and takeout, influencing sex-specific mating and feeding behaviour. Gene expression in biparental males is similar to that in non-caring states. Thus, being ‘biparental’ in N. vespilloides describes the family social organization rather than the number of directly parenting individuals. There was no specialization; instead, in biparental families, direct male parental care appears to be limited with female behaviour unchanged. This should lead to strong sexual conflict.Publisher PDFPeer reviewe

Vitellogenin and vitellogenin receptor gene expression is associated with male and female parenting in a subsocial insect

Complex social behaviour in Hymenoptera has been hypothesized to evolve by co-opting reproductive pathways (the ovarian ground plan hypothesis, OGPH) and gene networks (the reproductive ground plan hypothesis, RGPH). In support of these hypotheses, in eusocial Hymenoptera where there is reproductive division of labour, the yolk precursor protein vitellogenin (Vg) influences the expression of worker social behaviour. We suggest that co-opting genes involved in reproduction may occur more generally than just in the evolution of eusociality; i.e. underlie earlier stages of social evolution such as the evolution of parental care, given that reproduction and parental care rarely overlap. We therefore examined vitellogenin ( vg ) gene expression associated with parental care in the subsocial beetle Nicrophorus vespilloides . We found a significant reduction in the expression of vg and its receptor, vgr , in head tissue during active parental care, and confirmed that the receptor is expressed in the brains of both sexes. Ours is the first study to show that vgr is expressed in the brain of a non-eusocial insect. Given the association between behaviour and gene expression in both sexes, and the presence of vitellogenin receptors in the brain, we suggest that Vg was co-opted early in the evolution of sociality to have a regulatory function. This extends the association of Vg in parenting to subsocial species and outside of the Hymenoptera, and supports the hypothesis that the OGPH is general and that heterochrony in gene expression is important in the evolution of social behaviour and precedes subsequent evolutionary specialization of social roles. </jats:p

Opioid Receptor Probes Derived from Cycloaddition of the Hallucinogen Natural Product Salvinorin A

As part of our continuing efforts toward more fully understanding the structure−activity relationships of the neoclerodane diterpene salvinorin A, we report the synthesis and biological characterization of unique cycloadducts through [4+2] Diels−Alder cycloaddition. Microwave-assisted methods were developed and successfully employed, aiding in functionalizing the chemically sensitive salvinorin A scaffold. This demonstrates the first reported results for both cycloaddition of the furan ring and functionalization via microwave-assisted methodology of the salvinorin A skeleton. The cycloadducts yielded herein introduce electron-withdrawing substituents and bulky aromatic groups into the C-12 position. Kappa opioid (KOP) receptor space was explored through aromatization of the bent oxanorbornadiene system possessed by the cycloadducts to a planar phenyl ring system. Although dimethyl- and diethylcarboxylate analogues 5 and 6 retain some affinity and selectivity for KOP receptors and are full agonists, their aromatized counterparts 13 and 14 have reduced affinity for KOP receptors. The methods developed herein signify a novel approach toward rapidly probing the structure−activity relationships of furan-containing natural products

Event attribution of Parnaíba River floods in Northeastern Brazil

The climate modeling techniques of event attribution enable systematic assessments of the extent that anthropogenic climate change may be altering the probability or magnitude of extreme events. In the consecutive years of 2018, 2019, and 2020, rainfalls caused repeated flooding impacts in the lower Parnaíba River in Northeastern Brazil. We studied the effect that alterations in precipitation resulting from human influences on the climate had on the likelihood of flooding using two ensembles of the HadGEM3-GA6 atmospheric model: one driven by both natural and anthropogenic forcings; and the other driven only by natural atmospheric forcings, with anthropogenic changes removed from sea surface temperatures and sea ice patterns. We performed hydrological modeling to base our assessments on the peak annual streamflow. The change in the likelihood of flooding was expressed in terms of the ratio between probabilities of threshold exceedance estimated for each model ensemble. With uncertainty estimates at the 90% confidence level, the median (5% 95%) probability ratio at the threshold for flooding impacts in the historical period (1982–2013) was 1.12 (0.97 1.26), pointing to a marginal contribution of anthropogenic emissions by about 12%. For the 2018, 2019, and 2020 events, the median (5% 95%) probability ratios at the threshold for flooding impacts were higher at 1.25 (1.07 1.46), 1.27 (1.12 1.445), and 1.37 (1.19 1.59), respectively; indicating that precipitation change driven by anthropogenic emissions has contributed to the increase of likelihood of these events by about 30%. However, there are other intricate hydrometeorological and anthropogenic processes undergoing long-term changes that affect the flood hazard in the lower Parnaíba River. Trend and flood frequency analyses performed on observations showed a nonsignificant long-term reduction of annual peak flow, likely due to decreasing precipitation from natural climate variability and increasing evapotranspiration and flow regulation

TElmisartan in the management of abDominal aortic aneurYsm (TEDY): The study protocol for a randomized controlled trial

Background: Experimental studies suggest that angiotensin II plays a central role in the pathogenesis of abdominal aortic aneurysm. This trial aims to evaluate the efficacy of the angiotensin receptor blocker telmisartan in limiting the progression of abdominal aortic aneurysm. Methods/Design: Telmisartan in the management of abdominal aortic aneurysm (TEDY) is a multicentre, parallel-design, randomised, double-blind, placebo-controlled trial with an intention-to-treat analysis. We aim to randomly assign 300 participants with small abdominal aortic aneurysm to either 40 mg of telmisartan or identical placebo and follow patients over 2 years. The primary endpoint will be abdominal aortic aneurysm growth as measured by 1) maximum infra-renal aortic volume on computed tomographic angiography, 2) maximum orthogonal diameter on computed tomographic angiography, and 3) maximum diameter on ultrasound. Secondary endpoints include change in resting brachial blood pressure, abdominal aortic aneurysm biomarker profile and health-related quality of life. TEDY is an international collaboration conducted from major vascular centres in Australia, the United States and the Netherlands. Discussion: Currently, no medication has been convincingly demonstrated to limit abdominal aortic aneurysm progression. TEDY will examine the potential of a promising treatment strategy for patients with small abdominal aortic aneurysms. Trial registration: Australian and Leiden study centres: Australian New Zealand Clinical Trials Registry ACTRN12611000931976, registered on 30 August 2011; Stanford study centre: clinicaltrials.gov NCT01683084, registered on 5 September 2012

The Genome and Methylome of a Beetle with Complex Social Behavior,Nicrophorus vespilloides(Coleoptera: Silphidae)

Testing for conserved and novelmechanisms underlying phenotypic evolution requires a diversity of genomes available for comparisonspanning multiple independent lineages. For example, complex social behavior in insects has been investigated primarily witheusocial lineages, nearly all of which are Hymenoptera. If conserved genomic influences on sociality do exist, we need data from awider range of taxa that also vary in their levels of sociality. Here,we present the assembled and annotated genome of the subsocialbeetle Nicrophorus vespilloides, a species long used to investigate evolutionary questions of complex social behavior. We used thisgenome to address two questions. First, do aspects of life history, such as using a carcass to breed, predict overlap in gene modelsmore strongly than phylogeny? We found that the overlap in gene models was similar between N. vespilloides and all other insectgroups regardless of life history. Second, like other insects with highly developed social behavior but unlike other beetles, doesN. vespilloides have DNA methylation?We found strong evidence for an active DNA methylation system. The distribution of methylationwassimilar to other insects with exons having themostmethylatedCpGs. Methylation status appears highly conserved; 85%of themethylated genes in N. vespilloides are alsomethylated in the hymentopteran Nasonia vitripennis. The addition of this genomeadds a coleopteran resource to answer questions about the evolution and mechanistic basis of sociality and to address questionsabout the potential role of methylation in social behavior