The brain is inherently bisexual, differentiating during development so that in adulthood, males mount receptive females. Yet, vestiges of this bisexuality persist in adults, with heterotypical behaviors (females mounting and males being receptive) observed in some species. Consequently, differences in sexual behavior between the sexes, and between individuals of the same sex, are reflective of the predisposition and degree to which these behaviors are exhibited. How one behavior is facilitated and its complement simultaneously suppressed during a reproductive encounter suggests that behavioral expression is gated in some manner. Because male and female vertebrates typically display behavior characteristic of their own sex, simultaneous study of neural circuits gating homotypical and heterotypical behaviors in conventional animal models has received scant attention. The whiptail lizard species, Cnemidophorus uniparens, comprises individuals that are genetically and hormonally female, and that naturally display both types of behavior. Using High Pressure Liquid Chromatography (HPLC), immunocytochemistry, in situ hybridization, intracranial surgeries, as well as pharmacological and behavioral analyses, I report that serotonin levels, and signaling via distinct serotonergic receptors at behaviorally relevant brain nuclei might allow the system to switch between either behavioral repertoire. The use of the same molecule to mediate the reciprocal inhibition of complementary behavioral repertories within the same sex is evidence of a phenomenon of molecular parsimony underlying a striking form of behavioral plasticity. This dissertation also illustrates that sexually differentiated traits such as male and female-typical sexual behaviors are sculpted by neurochemical signaling at neural substrates present in both sexes. / text

The ‘food desert’ has become a popular metaphor for describing fragmented pockets of America’s retail food environment characterized by limited access to affordable healthy foods and consequent heightened incidences of obesity and other diet-related health problems. Although researchers have addressed the locations and boundaries of food deserts, influential cross-sectional analyses are limited in that they cannot identify the direction of causality between the food environment and health outcomes. This study approaches the problem from an ecological perspective that examines the interplay between retailer and consumer in urban and rural settings of both food desert and non-food desert areas in the Texas South Plains centered on Lubbock. The principle methods of data collection entailed observations of purchases at full-service grocery stores and administration of a short survey as a means to determining what foods are being purchased and why. Additional semi-structured interviews with store representatives, along with several individuals located in underserved areas, and a general familiarization with the larger retail food environment, focusing on convenience and discount stores, provided important context to the research. The results challenge many existing assumptions, indicating problems associated with linking food deserts to poor health outcomes without accounting for additional variables, and further provides strong evidence that consumer choice is responsible for the larger retail food environment. / text

The objective of this project is to apply the Optical Stimulated Luminescence (OSL) technique to date the palaeo sediment from Mu Us Desert, part of the Inner Mongolia in northern China and reconstruct the palaeo environment. Five OSL samples were collected from Dagouwan, Salawusu River Valley at Inner Mongolia by Dr S. H. Li and his team in 2009. Extraction of 150μm to 180μm silt-size feldspar from collected dune sand, lacustrine facies and fluvial facies samples and running of luminescence dating therefore to obtain the age from 50ka to 90ka. Climate proxies - magnetic susceptibility, grain size, fossil vertebrates and fossil pollens have been analyzed and it is concluded that significant climate change occurred within this period, which change from domination of warm, humid and rainy summer monsoons (before 70ka) to cold, wind, windy strengthened dry winter wind and back to warm and humid again after 55ka. / published_or_final_version / Applied Geosciences / Master / Master of Science

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