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ABSTRACT There is great interspecific variation in the nutritional composition of natural diets, and the varied nutritional content is physiologically tolerated because of evolutionarily based balances between diet composition and processing ability. However, as a result of landscape change and human exposure, unnatural diets are becoming widespread among wildlife without the necessary time for evolutionary matching between the diet and its processing. We tested how a controlled, unnatural high glucose diet affects glucose tolerance using captive green iguanas, and we performed similar glucose tolerance tests on wild Northern Bahamian rock iguanas that are either frequently fed grapes by tourists or experience no such supplementation. We evaluated both short and longer-term blood glucose responses and corticosterone (CORT) concentrations as changes have been associated with altered diets. Experimental glucose supplementation in the laboratory and tourist feeding in the wild both significantly affected glucose metabolism. When iguanas received a glucose-rich diet, we found greater acute increases in blood glucose following a glucose challenge. Relative to unfed iguanas, tourist-fed iguanas had significantly lower baseline CORT, higher baseline blood glucose, and slower returns to baseline glucose levels following a glucose challenge. Therefore, unnatural consumption of high amounts of glucose alters glucose metabolism in laboratory iguanas with short-term glucose treatment and free-living iguanas exposed to long-term feeding by tourists. Based on these results and the increasing prevalence of anthropogenically altered wildlife diets, the consequences of dietary changes on glucose metabolism should be further investigated across species, as such changes in glucose metabolism have health consequences in humans (e.g. diabetes). 

A diagnostic of thirty questions administered to incoming STEM students in Fall 2013 and Fall 2015 - Fall 2018 reflects that their spatial visualization skills (SVS) need to be improved. Previous studies in the SVS subject [1], [2], [3] report that well-developed SVS skills lead to students’ success in Engineering and Technology, Computer Science, Chemistry, Computer Aided Design and Mathematics. Authors [4], [5] mention that aptitude in spatial skills is gradually becoming a standard assessment of an individual’s likelihood to succeed as an engineer. This research reports the qualitative and quantitative results of a project designed to improve SVS’s for STEM students managed under two strategies. The first strategy utilized was a series of face-to-face (FtF), two-hour training sessions taught over six weeks to all majors in STEM. This strategy was offered in Spring 2014 and every semester from Fall 2015 - Spring 2018. The second strategy was an embedded training (ET) implemented by one faculty from Fall 2017- Fall 2018. The faculty embedded the training in the US 1100 freshman seminar and was highly motivated to increase awareness of students on the importance and applicability of SVS in their fields of study. As reported by Swail et al. [6], cognitive, social, and institutional factors are key elements to best support students’ persistence and achievement. Both interventions used in this project encompassed all these factors and were supported by an NSF IUSE grant (2015-2019) to improve STEM retention. The FtF training was taken by 34 students majoring in diverse STEM fields. Its effectiveness was statistically assessed through a t-test to compare the results in the Purdue Spatial Visualization Skills Test - Rotations before and after the training and through analysis of surveys. Results were very positive; 85.29% of the participants improved their scores. The average change in scores was 5.29 (from 16.85 to 22.15; 17.65% improvement) and it was statistically significant (p-value 3.9E-8). On the surveys, 90% of students answered that they were satisfied with the training. Several students reported that they appreciated a connection between SVS, Calculus II and Engineering Graphics classes while others based the satisfaction on perceiving the critical role SVS will play in their careers. Results from the ET strategy were also encouraging. Teaching methods, curriculum and results are discussed in this paper. Adjustments to the teaching methods were done over 3 semesters. In the last semester, the faculty found that covering the modules at a slower pace than in the FtF training, asking the students to complete the pre-and post-diagnostic in class, and introducing the Spatial VisTM app to provide students with additional practice were key elements to assure students success and satisfaction. In conclusion, both strategies were demonstrated to be powerful interventions to increase students’ success because they not only offer students, particularly freshman, a way to refine SVS but also increase motivation in STEM while creating a community among students and faculty. The ET is effective and apt to be institutionalized. Lastly, this experimental research strengthens the literature on SVS. 

Tyrosine kinase receptor (RTK) ligation and dimerization is a key mechanism for translating external cell stimuli into internal signaling events. This process is critical to several key cell and physiological processes, such as in angiogenesis and embryogenesis, among others. While modulating RTK activation is a promising therapeutic target, RTK signaling axes have been shown to involve complicated interactions between ligands and receptors both within and across different protein families. In angiogenesis, for example, several signaling protein families, including vascular endothelial growth factors and platelet-derived growth factors, exhibit significant cross-family interactions that can influence pathway activation. Computational approaches can provide key insight to detangle these signaling pathways but have been limited by the sparse knowledge of these cross-family interactions. Here, we present a framework for studying known and potential non-canonical interactions. We constructed generalized models of RTK ligation and dimerization for systems of two, three and four receptor types and different degrees of cross-family ligation. Across each model, we developed parameter-space maps that fully determine relative pathway activation for any set of ligand-receptor binding constants, ligand concentrations and receptor concentrations. Therefore, our generalized models serve as a powerful reference tool for predicting not only known ligand: Receptor axes but also how unknown interactions could alter signaling dimerization patterns. Accordingly, it will drive the exploration of cross-family interactions and help guide therapeutic developments across processes like cancer and cardiovascular diseases, which depend on RTK-mediated signaling. 

Reptiles rely on thermal heat exchange to achieve body temperatures (T_body) conducive to maintaining homeostasis. Diurnal changes in the thermal environment are therefore liable to influence allostatic mediation of survival processes (e.g., immunity) during environmental challenges or stressors. However, the extent to whichT_bodyprompts individual variation in physiology remains largely unexplored in reptiles. Our study tested how circulating energy‐mobilizing hormone, energy metabolites, and immunity can vary across basal and stress‐induced allostatic states for plateau side‐blotched lizards (Uta stansburiana uniformis) residing in a heterogeneous thermal environment. We collected baseline and acute stress blood samples from male lizards to compare changes in plasma corticosterone (CORT), glucose, and bacterial killing ability (BKA) in relation to each other andT_body. We hypothesized each physiological parameter differs between allostatic states, whereby stress‐induced activity increases from baseline. At basal and stress‐induced states, we also hypothesized circulating CORT, glucose, and BKA directly correspond with each other andT_body. We found both CORT and BKA increased while glucose instead decreased from acute stress. At basal and stress‐induced allostatic states, we found CORT to be directly related toT_bodywhile BKA was inversely related to CORT. We also found BKA and glucose were directly related at baseline, but inversely related following acute stress. Overall, these results demonstrate allostatic outcomes from acute stress in a free‐living reptile and the role of temperature in mediating energetic state and immunity. Future research on reptilian allostasis should consider multiple environmental conditions and their implications for physiological performance and survival.

 

Recent data reveal that a higher percentage of Black women (9.7%) are enrolled in college than any other group, topping Asian women (8.7%), White women (7.1%) and White men (6.1%). Despite these gains in college attendance, Black women are often underrepresented in the fields of engineering and computer science. This paper presents the findings from a qualitative study that investigated the identity and experiences of Black women who are pursuing doctoral degrees in engineering and computer science. This research is grounded on the tenet that one cannot effectively serve or impact a community until he/she genuinely understands the issues and challenges facing the people who are its members. This work explores how Black female doctoral students persist in environments where they are grossly underrepresented. Content analysis is used to examine interview data obtained from 13 Black women who are pursing doctoral degrees in engineering and computer science. This paper concludes with some of the key challenges these women face in their programs on a daily basis. The goal of this research is to bring awareness to not only the challenges, but also potential strategies to increase the retention and persistence of Black women in engineering and computer science across all academic levels. 

While there is huge promise in monitoring physiological parameters in free‐living organisms, we also find high amounts of variability over time and space. This variation requires us to capitalize on long‐term physiological monitoring to adequately address questions of population health, conservation status, or evolutionary trends as long‐term sampling can examine ecoimmunological and endocrine interactions in wild populations while accounting for the variation that often makes ecophysiological field studies difficult to compare. In this study, we tested how immune efficacy and endocrinology interact while accounting for ecological context and environmental conditions in two snake species. Specifically, we measured bacterial killing ability, steroid hormones, and morphological characteristics in multiple populations of the Western Terrestrial Gartersnake (Thamnophis elegans)and Common Gartersnake (T. sirtalis)for multiple seasons over 6 years. Leveraging this long‐term dataset, we tested how a broad immune measure and endocrine endpoints interact while accounting for individual traits, sampling date, and environmental conditions. Across both species, we found bacterial killing ability to be directly related to corticosterone (CORT) and temperature and greater overall in the spring compared to the fall. We found CORT and testosterone yielded relationships with individual sex, sampling temperature, and time of year. Wild populations can exhibit high amounts of variation in commonly collected physiological endpoints, highlighting the complexity and difficulty inherent in interpreting single endpoints without taking ecological and environmental conditions into account. Our study emphasizes the importance of reporting the environmental conditions under which the sampling occurred to allow for better contextualization and comparison between studies.