Virtual Engineering Sciences Learning Lab: Giving STEM Education a Second Life

Engineering education in the 21st century faces multiple obstacles including limited accessibility of course resources due, in part, to the costs associated with acquiring and maintaining equipment and staffing laboratories. Another continuing challenge is the low level of participation of women and other groups historically underrepresented in STEM disciplines. As a partial remedy for these issues, we established a Virtual Engineering Sciences Learning Lab (VESLL) that provides interactive objects and learning activities, multimedia displays, and instant feedback procedures in a virtual environment to guide students through a series of key quantitative skills and concepts. Developed in the online virtual world Second LifeTM, VESLL is an interactive environment that supports STEM education, with potential to help reach women and other underrepresented groups. VESLL exposes students to various quantitative skills and concepts through visualization, collaborative games, and problem solving with realistic learning activities. Initial assessments have demonstrated high student interest in VESLL\u27s potential as a supplementary instructional tool and show that student learning experiences were improved by use of VESLL. Ultimately, the VESLL project contributes to the ongoing body of evidence suggesting that online delivery of course content has remarkable potential when properly deployed by STEM educators

Evaluation of atlas-based segmentation of hippocampi in healthy humans

Introduction and aim: Region of interest (ROI)-based functional magnetic resonance imaging (fMRI) data analysis relies on extracting signals from a specific area which is presumed to be involved in the brain activity being studied. The hippocampus is of interest in many functional connectivity studies for example in epilepsy as it plays an important role in epileptogenesis. In this context, ROI may be defined using different techniques. Our study aims at evaluating the spatial correspondence of hippocampal ROIs obtained using three brain atlases with hippocampal ROI obtained using an automatic segmentation algorithm dedicated to the hippocampus. Material and methods: High-resolution volumetric T1-weighted MR images of 18 healthy volunteers (five females) were acquired on a 3T scanner. Individual ROIs for both hippocampi of each subject were segmented from the MR images using an automatic hippocampus and amygdala segmentation software called SACHA providing the gold standard ROI for comparison with the atlas-derived results. For each subject, hippocampal ROIs were also obtained using three brain atlases: PickAtlas available as a commonly used software toolbox; automated anatomical labeling (AAL) atlas included as a subset of ROI into PickAtlas toolbox and a frequency-based brain atlas by Hammers et al. The levels of agreement between the SACHA results and those obtained using the atlases were assessed based on quantitative indices measuring volume differences and spatial overlap. The comparison was performed in standard Montreal Neurological Institute space, the registration being obtained with SPM5 (http://www.fil.ion.ucl.ac.uk/spm/). Results: The mean volumetric error across all subjects was 73% for hippocampal ROIs derived from AAL atlas; 20% in case of ROIs derived from the Hammers atlas and 107% for ROIs derived from PickAtlas. The mean false-positive and false-negative classification rates were 60% and 10% respectively for the AAL atlas; 16% and 32% for the Hammers atlas and 6% and 72% for the PickAtlas. Conclusion: Though atlas-based ROI definition may be convenient, the resulting ROIs may be poor representations of the hippocampus in some studies critical to under- or oversampling. Performance of the AAL atlas was inferior to that of the Hammers atlas. Hippocampal ROIs derived from PickAtlas are highly significantly smaller, and this results in the worst performance out of three atlases. It is advisable that the defined ROIs should be verified with knowledge of neuroanatomy before using it for further data analysis

Virtual Engineering Sciences Learning Lab: Giving STEM Education a Second Life

Engineering education in the 21st century faces multiple obstacles including limited accessibility of course resources due, in part, to the costs associated with acquiring and maintaining equipment and staffing laboratories. Another continuing challenge is the low level of participation of women and other groups historically underrepresented in STEM disciplines. As a partial remedy for these issues, we established a Virtual Engineering Sciences Learning Lab (VESLL) that provides interactive objects and learning activities, multimedia displays, and instant feedback procedures in a virtual environment to guide students through a series of key quantitative skills and concepts. Developed in the online virtual world Second LifeTM, VESLL is an interactive environment that supports STEM education, with potential to help reach women and other underrepresented groups. VESLL exposes students to various quantitative skills and concepts through visualization, collaborative games, and problem solving with realistic learning activities. Initial assessments have demonstrated high student interest in VESLL\u27s potential as a supplementary instructional tool and show that student learning experiences were improved by use of VESLL. Ultimately, the VESLL project contributes to the ongoing body of evidence suggesting that online delivery of course content has remarkable potential when properly deployed by STEM educators

Early-life conditions impact juvenile telomere length, but do not predict later life-history strategies or fitness in a wild vertebrate

Environmental conditions experienced during early life may have long-lasting effects on later-life phenotypes and fitness. Individuals experiencing poor early-life conditions may suffer subsequent fitness constraints. Alternatively, individuals may use a strategic “Predictive Adaptive Response” (PAR), whereby they respond—in terms of physiology or life-history strategy—to the conditions experienced in early life to maximize later-life fitness. Particularly, the Future Lifespan Expectation (FLE) PAR hypothesis predicts that when poor early-life conditions negatively impact an individual's physiological state, it will accelerate its reproductive schedule to maximize fitness during its shorter predicted life span. We aimed to measure the impact of early-life conditions and resulting fitness across individual lifetimes to test predictions of the FLE hypothesis in a wild, long-lived model species. Using a long-term individual-based dataset, we investigated how early-life conditions are linked with subsequent fitness in an isolated population of the Seychelles warbler Acrocephalus sechellensis. How individuals experience early-life environmental conditions may vary greatly, so we also tested whether telomere length—shorter telomers are a biomarker of an individual's exposure to stress—can provide an effective measure of the individual-specific impact of early-life conditions. Specifically, under the FLE hypothesis, we would expect shorter telomeres to be associated with accelerated reproduction. Contrary to expectations, shorter juvenile telomere length was not associated with poor early-life conditions, but instead with better conditions, probably as a result of faster juvenile growth. Furthermore, neither juvenile telomere length, nor other measures of early-life conditions, were associated with age of first reproduction or the number of offspring produced during early life in either sex. We found no support for the FLE hypothesis. However, for males, poor early-life body condition was associated with lower first-year survival and reduced longevity, indicating that poor early-life conditions pose subsequent fitness constraints. Our results also showed that using juvenile telomere length as a measure of early-life conditions requires caution, as it is likely to not only reflect environmental stress but also other processes such as growth

Subordinate females in the cooperatively breeding Seychelles warbler obtain direct benefits by joining unrelated groups

1. In many cooperatively breeding animals, a combination of ecological constraints and benefits of philopatry favours offspring taking a subordinate position on the natal territory instead of dispersing to breed independently. However, in many species individuals disperse to a subordinate position in a non-natal group ("subordinate between-group" dispersal), despite losing the kin-selected and nepotistic benefits of remaining in the natal group. It is unclear which social, genetic and ecological factors drive between-group dispersal. 2. We aim to elucidate the adaptive significance of subordinate between-group dispersal by examining which factors promote such dispersal, whether subordinates gain improved ecological and social conditions by joining a non-natal group, and whether between-group dispersal results in increased lifetime reproductive success and survival. 3. Using a long-term dataset on the cooperatively-breeding Seychelles warbler (Acrocephalus sechellensis), we investigated how a suite of proximate factors (food availability, group composition, age and sex of focal individuals, population density) promote subordinate between-group dispersal by comparing such dispersers with subordinates that dispersed to a dominant position or became floaters. We then analysed whether subordinates that moved to a dominant or non-natal subordinate position, or became floaters, gained improved conditions relative to the natal territory, and compared fitness components between the three dispersal strategies. 4. We show that individuals that joined another group as non-natal subordinates were mainly female and that, similar to floating, between-group dispersal was associated with social and demographic factors that constrained dispersal to an independent breeding position. Between-group dispersal was not driven by improved ecological or social conditions in the new territory and did not result in higher survival. Instead, between-group dispersing females often became co-breeders, obtaining maternity in the new territory, and were likely to inherit the territory in the future, leading to higher lifetime reproductive success compared to females that floated. Males never reproduced as subordinates, which may be one explanation why subordinate between-group dispersal by males is rare. 5. Our results suggest that subordinate between-group dispersal is used by females to obtain reproductive benefits when options to disperse to an independent breeding position are limited. This provides important insight into the additional strategies that individuals can use to obtain reproductive benefits

Ishemia-Reperfusion enhances GAPDH nitration in aging skeletal muscle

Aging and skeletal muscle ischemia/reperfusion (I/R) injury leads to decreased contractile force generation that increases severely with age. Our studies show that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) protein expression is significantly decreased at 3 and 5 days reperfusion in the young mouse muscle and at 1, 3, 5, and 7 days in the aged muscle. Using PCR, we have shown that GAPDH mRNA levels in young and old muscle increase at 5 days reperfusion compared to control, suggesting that the protein deficit is not transcriptional. Furthermore, while total tyrosine nitration did not increase in the young muscle, GAPDH nitration increased significantly at 1 and 3 days reperfusion. In contrast, total tyrosine nitration in aged muscle increased significantly at 1, 3, and 5 days of reperfusion, with increases in GAPDH nitration at the same time points. We conclude that GAPDH protein levels decrease following I/R, that this is not transcriptionally mediated, that the aged muscle experiences greater oxidative stress, protein modification and GAPDH degradation, possibly contributing to decreased muscle function. We propose that tyrosine nitration enhances GAPDH degradation following I/R and that the persistent decrease of GAPDH in aged muscle is due to the prolonged increase in oxidative modification in this age group

Seychelles warblers with silver spoons: Juvenile body mass is a lifelong predictor of annual survival, but not annual reproduction or senescence

The environment experienced during development, and its impact on intrinsic condition, can have lasting outcomes for individual phenotypes and could contribute to variation in adult senescence trajectories. However, the nature of this relationship in wild populations remains uncertain, owing to the difficulties in summarizing natal conditions and in long-term monitoring of individuals from free-roaming long-lived species. Utilizing a closely monitored, closed population of Seychelles warblers (Acrocephalus sechellensis), we determine whether juvenile body mass is associated with natal socioenvironmental factors, specific genetic traits linked to fitness in this system, survival to adulthood, and senescence-related traits. Juveniles born in seasons with higher food availability and into smaller natal groups (i.e., fewer competitors) were heavier. In contrast, there were no associations between juvenile body mass and genetic traits. Furthermore, size-corrected mass—but not separate measures of natal food availability, group size, or genetic traits—was positively associated with survival to adulthood, suggesting juvenile body mass is indicative of natal condition. Heavier juveniles had greater body mass and had higher rates of annual survival as adults, independent of age. In contrast, there was no association between juvenile mass and adult telomere length attrition (a measure of somatic stress) nor annual reproduction. These results indicate that juvenile body mass, while not associated with senescence trajectories, can influence the likelihood of surviving to old age, potentially due to silver-spoon effects. This study shows that measures of intrinsic condition in juveniles can provide important insights into the long-term fitness of individuals in wild populations