Rhinoceros auklet developmental responses to moderate food restriction

Thesis (M.S.) University of Alaska Fairbanks, 2007Seabird nestlings are vulnerable to food restriction because their parents may not buffer them from prey shortages. I conducted a captive study to explore how rhinoceros auklet chicks (Cerorhinca monocerata) may cope with food restriction and avoid long-term fitness consequences. I predicted auklet nestlings would be adapted to moderate levels of food-stress, and investigated how morphological allocation, glucocorticoid stress response, and fledging behavior change under conditions of a 50% calorie restriction. I also investigated effects of growth and food restriction on carbon and nitrogen stable isotope ratios ([delta]¹³C and [delta]¹⁵N) in auklet tissues. I found that food-restricted auklets allocated resources heavily toward skeletal growth, most notably toward wingchord growth. Restricted auklets exhibited a muted adrenocortical response, increasing glucocorticoid levels only slightly in response to food restriction. Fledging decision was not affected by restriction, with restricted and well-fed chicks fledging at approximately the same age. Both growth and food restriction caused decreases in [delta]¹⁵N of auklet red blood cells (RBCs), but caused no change in [delta]¹³C. Sampling of free-living auklets revealed that natural levels of variability were low for RBC isotope ratios, indicating that the effects of growth and restriction detected in the captive study are of biological significance.1. Rhinoceros auklet development responses to food limitation : potential coping mechanisms and post-fledging consequences -- 2. Disentagling effects of age and nutritional status on seabird stable isotope ratios -- General conclusion

Spatial Analysis of Travel Demand and Accessibility in Vermont: Where will EVs work?

The suitability and charging requirements of electric vehicles (EVs) may differ in rural areas, where the electrical grid may be less robust and daily VMT higher. Although other studies have examined issues of regional power requirements of EVs, none have done so in conjunction with the spatial considerations of travel demand and accessibility. We use three datasets to forecast the future spatial distribution of EVs, as well as to assess these vehicles’ ability to meet current daily travel demand: the National Household Travel Survey (NHTS), geocoded Vermont vehicle fleet data, and an E911 geocoded dataset of every building statewide. We consider spatial patterns in existing daily travel and homebased tours to consider EV charging locations, as well as area-types that are unsuited for widespread electric vehicle adoption. We also consider how built environment attributes, including residential and commercial density and retail accessibility, affect travel demand and thus future EV energy requirements. We found that existing hybrid vehicles were more likely to be located near other hybrids than conventional vehicles were. This clustering of current hybrid vehicles, in both urban and rural areas, suggests that the distribution of future EVs may also be clustered. Our analysis suggests that between 69 and 84% of the state’s vehicles could be replaced by a 40-mile range EV, and 96-99% could be replaced by a 100-mile EV, depending on the availability of workplace charging. We did not find a strong relationship between land-use and travel demand, perhaps due to our low number of urban data points, the highly variable nature of rural travel, and the limitations of using a one-day travel log dataset. Our results suggest EVs are a viable option to serve existing travel demand by rural residents but may require special consideration for power supply and vehicle charging infrastructure

American Gut: an Open Platform for Citizen Science Microbiome Research

McDonald D, Hyde E, Debelius JW, et al. American Gut: an Open Platform for Citizen Science Microbiome Research. mSystems. 2018;3(3):e00031-18