Winter diets of round whitefish Prosopium cylindraceum in the St. Marys River

The round whitefish (Prosopium cylindraceum) is a coregonine native to numerous northern temperate lentic and lotic systems across North America. The St. Marys River, located between the United States and Canadian border, is one such system where the round whitefish supports a recreational fishery and is a prey source for piscivores. Round whitefish are generally known to prey upon benthic macroinvertebrates, but diets of round whitefish in the St. Marys River have not been characterized. We analyzed stomach contents from 107 round whitefish sampled from the St. Marys River during the winter months of 2020 and 2021 to describe their diets, examine their feeding strategies, and determine if they fed selectively. Ephemeropterans were the most important prey numerically, followed by megalopterans, trichopterans, and dipterans. The round whitefish population sampled from the St. Marys River exhibited a specialized feeding strategy that most often specialized on ephemeropterans. Patterns in the importance of prey types and feeding strategy were consistent between both years sampled. Selective feeding by round whitefish was examined using diet and environmental data from 2021 only, and we found that round whitefish selected both ephemeropterans and megalopterans, but avoided trichopterans and dipterans. Rather than being opportunistic invertivores, our results indicate round whitefish are specialized and selective feeders. Our findings can be used to inform conservation and management of round whitefish, as diets represent an integration of multiple ecological components such as prey availability, predator behavior, and habitat quality.     

Historical and contemporary movement and survival rates of walleye (Sander vitreus) in Lake Winnipeg,Canada

Understanding patterns of fish movement in large lake ecosystems is essential for determining appropriate management actions as differences in movement behaviour can influence life history traits such as growth and survival. Lake Winnipeg in Manitoba, Canada supports the 2nd largest walleye (Sander vitreus) commercial fishery in North America. We used mark-recapture models to determine movement and estimate survival of walleye between basins of Lake Winnipeg in historical and contemporary contexts, comparing a tag-recovery study completed historically during 1974–1977 with a contemporary (2017–2019) acoustic telemetry study. Mark-recapture models revealed comparably low but detectable annual transitions between basins from historical (0.3–1.2%) and contemporary datasets (7–8.5%). Historically, fish > 300 mm more frequently moved in a south to north direction. Contemporary estimates suggest similar length-based directionality in that fish > 350 mm were always more likely to move in a south-north direction. Contemporary annual survival derived from mark-recapture models ranged between 27 and 45% and 64.3% when derived from catch curve analysis, while independently derived annual historical survival estimates ranged between 50 and 69% and 45.5% from catch curve analysis. Using the contemporary dataset, we also observed seasonal variation in movement and survival between basins, with the greatest movement across the lake occurring during the fall. Our results demonstrate a persisting pattern of low but measurable movement, suggesting between basin movement is not unusual for Lake Winnipeg. Further, low walleye survival rates reported here for the two time periods studied, support recent management actions to reduce fishing pressure across the lake.     

Transposable Elements and Stress in Vertebrates: An Overview

Since their identification as genomic regulatory elements, Transposable Elements (TEs) were considered, at first, molecular parasites and later as an important source of genetic diversity and regulatory innovations. In vertebrates in particular, TEs have been recognized as playing an important role in major evolutionary transitions and biodiversity. Moreover, in the last decade, a significant number of papers has been published highlighting a correlation between TE activity and exposition to environmental stresses and dietary factors. In this review we present an overview of the impact of TEs in vertebrate genomes, report the silencing mechanisms adopted by host genomes to regulate TE activity, and finally we explore the effects of environmental and dietary factor exposures on TE activity in mammals, which is the most studied group among vertebrates. The studies here reported evidence that several factors can induce changes in the epigenetic status of TEs and silencing mechanisms leading to their activation with consequent effects on the host genome. The study of TE can represent a future challenge for research for developing effective markers able to detect precocious epigenetic changes and prevent human diseases.     

Use of Time Series Analysis to Evaluate the Impacts of Underground Mining on the Hydraulic Properties of Groundwater of Dysart Woods,Ohio

Mine Water and the Environment - Dysart Woods is the largest (≈ 23 ha) old-growth forest in southeastern Ohio. It was donated to Ohio University for research purpose and public...     

Are multimodal travelers more satisfied with their lives? A study of accessibility and wellbeing in the Denver,Colorado metropolitan area

In this study, we ask how the ability to use multiple transportation options affects one's subjective wellbeing (SWB), including aspects such as physical health, financial security, standard of living, and personal relationships. A clearer understanding of these associations can inform investments in multimodal infrastructure. We draw on 232 surveys from a diverse set of residents in the Denver, Colorado metropolitan area and find that having more transportation choices can improve standard of living for low- and middle-income residents. Multimodal middle-income residents are also more satisfied with their health and what they are achieving in life. Vehicle owners report higher levels of satisfaction with their standard of living, health, and achievements, compared to non-owners, unless auto is their only travel mode. Only low-income respondents had significant differences in standard of living by where they lived, with greatest satisfaction in the urban core. These results confirm the relationship between public transit and SWB, and contribute to our understanding of how the concept of motility (social and spatial mobility) shapes one's quality of life. The findings have implications for investments in transportation modes across neighborhood types and populations, so that people have a range of travel options to meet their needs and increase their satisfaction with their goals through improved daily travel.     

Spatial Relationships of Water Resources with Energy Consumption at Coal Mining Operations in China

Mine Water and the Environment - The spatial characterization and regional differences of water use in China’s coal mines were investigated based on a high spatial resolution mine site...     

Systematic study of optoelectronic and transport properties of cesium lead halide (Cs2PbX6; X=Cl,Br, I) double perovskites for solar cell applications

A systematic density functional theory investigation of Cs₂PbX₆ (X = Cl, Br, I) double perovskites is presented. The lattice constants are computed after structure optimization and using Birch-Murnaghan equations, which agree to the experimental literature. The mechanical stability conditions satisfy Born criteria, and the ductile nature is evidenced by the calculated Poisson's (v) and Pugh's ratios (B₀/G) because all three double perovskites exhibit values higher than the respective critical values v = 0.26 and B₀/G = 1.75. A detailed study of the optoelectronic properties reveals these double perovskites as promising candidates for future optical devices due to their direct band gaps (within 0.45–2.54 eV) and large absorption coefficients 5.95 × 10⁵ cm⁻¹, which are suitable for solar cell applications. ZT calculations demonstrate minute variations within 200–800 K and computed parameter values are quite favorable for thermoelectric applications of these materials in the future. A p-type semiconducting nature is predicted by the computed thermoelectric properties. Additionally, computed refractive indices show Cs₂PbBr₆ and Cs₂PbI₆ exhibiting super-luminescent properties in the UV range. Therefore, the studied double perovskites provide further interest for future energy conversion and photonic based technologies.     

Pyrochlore doped Pr2Sn2O7 ceramics: Electronic transport properties and high NO2 sensitivity

This work proposed pyrochlore doped-Pr₂Sn₂O₇ ceramics with electronic transport and NO₂ sensitivity through molecular insights into sensing mechanism by DFT. NO₂ adsorbed on the p-type semiconductor metal oxide NiO(100) can be decomposed into three stable adsorbed states NO₂, NO and O that will obtain electrons from the NiO valence band to form N₂ (or N₂O) and O²⁻, resulting in an increase of the holes concentration. The results suggest that the response current value of the sensor based on Pr₂Sn₂O₇ doped by Ca²⁺ at A site is 53.5 times higher than that of commercial YSZ, indicating high sensitivity with 420 nA/ ppm at mild temperature 550 °C. Besides the creation of oxygen-defect sites, the electronic transport is responsible for the improved sensing properties. The electrons on doped Pr₂Sn₂O₇ ceramics can complement the hole-accumulation layer and make NO₂, NO, O accept electrons quickly to accelerate the rate of the electrochemical cyclic reaction.