Environmental Stressor Importance: Science versus Media

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152643/1/etc4606.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152643/2/etc4606_am.pd

Mechanisms, Risk Factors, and Management of Acquired Long QT Syndrome: A Comprehensive Review

Long QT syndrome is characterized by prolongation of the corrected QT (QTc) interval on the surface electrocardiogram and is associated with precipitation of torsade de pointes (TdP), a polymorphic ventricular tachycardia that may cause sudden death. Acquired long QT syndrome describes pathologic excessive prolongation of the QT interval, upon exposure to an environmental stressor, with reversion back to normal following removal of the stressor. The most common environmental stressor in acquired long QT syndrome is drug therapy. Acquired long QT syndrome is an important issue for clinicians and a significant public health problem concerning the large number of drugs with this adverse effect with a potentially fatal outcome, the large number of patients exposed to these drugs, and our inability to predict the risk for a given individual. In this paper, we focus on mechanisms underlying QT prolongation, risk factors for torsades de pointes and describe the short- and long-term treatment of acquired long QT syndrome

Online Learning and Academic Cyberloafing

In this study, we developed and tested a model examining the impact of environmental and technological stressors on academic cyberloafing, specifically interactive and noninteractive cyberloafing. We further examined the relationship between cyberloafing and in-class engagement (attention and absorption), as well as the mediating effect of cyberloafing on the relationships between the stressors and engagement. Data were collected through an online survey of 200 undergraduate students from a large university in Asia. Findings showed that only environmental stressor was positively related to interactive cyberloafing. Both stressors were positively related to non-interactive cyberloafing. Interactive cyberloafing was negatively related with, while non-interactive cyberloafing was positively related with engagement. Overall, non-interactive cyberloafing mediated all relationships between the stressors and both dimensions of engagement, while interactive cyberloafing only mediated the relationship between environmental stressor and absorption. Our results suggest that some cyberloafing activities can be rejuvenating for students. Implications for research and practice are discusse

Does maternal exposure to an environmental stressor affect offspring response to predators?

There is growing recognition of the ways in which maternal effects can influence offspring size, physiological performance, and survival. Additionally, environmental contaminants increasingly act as stressors in maternal environments, possibly leading to maternal effects on subsequent offspring. Thus, it is important to determine whether contaminants and other stressors can contribute to maternal effects, particularly under varied ecological conditions that encompass the range under which offspring develop. We used aquatic mesocosms to determine whether maternal effects of mercury (Hg) exposure shape offspring phenotype in the American toad (Bufo americanus) in the presence or absence of larval predators (dragonfly naiads). We found significant maternal effects of Hg exposure and significant effects of predators on several offspring traits, but there was little evidence that maternal effects altered offspring interactions with predators. Offspring from Hg-exposed mothers were 18% smaller than those of reference mothers. Offspring reared with predators were 23% smaller at metamorphosis than those reared without predators. There was also evidence of reduced larval survival when larvae were reared with predators, but this was independent of maternal effects. Additionally, 5 times more larvae had spinal malformations when reared without predators, suggesting selective predation of malformed larvae by predators. Lastly, we found a significant negative correlation between offspring survival and algal density in mesocosms, indicating a role for top-down effects of predators on periphyton communities. Our results demonstrate that maternal exposure to an environmental stressor can induce phenotypic responses in offspring in a direction similar to that produced by direct exposure of offspring to predators

Noise Calculation Charts and Indoor Environmental Quality for Evaluating Industrial Indoor Environment and Health

Noise, defined as “a sensation of unwanted intensity of a wave,” is perception of a pollutant and a type of environmental stressor. An environmental stressor such as noise may have detrimental effects on various aspects of health. The unwanted intensity of a wave is a propagation of noise due to transmission of waves (viz. physical agents) such as sun, light, sound, heat, electricity, fluid, and fire. The effects of these physical agents on human health as noise-intruding elements in an industrial indoor environment are discussed. Noise characterization is discussed from indoor air quality and health perspective. The noise calculation charts are detailed for interference of noise waves based on a benchmark solution. These charts calculate positive and negative magnitudes of noise based on noise characterization of waves due to power difference of two intensities. The noise interference is calculated from newly devised noise measurement equations and their units. The grades and flag colors are notated to the noise calculation charts. Furthermore, illustrated examples of noise characterization calculations for indoor environment are presented using devised noise measurement equations. Indoor environmental quality and noise instrumentation are discussed. Adverse effects of pollutants on human health are summarized. Ventilation systems for dispersion of pollutants from industrial indoor environment are also elaborated

Over a Decade of Comparative Risk Analysis: A Review of the Human Health Rankings

The author reviews a method for undertaking a cross-project comparison of comparative risk analyses to understand which environmental problem areas have been cited most as often posing the severest risks

The Use of a Habitat Quality Stress Index to Evaluate Stress as an Analog for Proximate Fitness in the American Crow Within a Matrix of Landcover Characteristics to Assess Its Potential Contribution to Disease Etiologies

All organisms occur within spatial and temporal environments to maximize proximate fitness (health) and thus life history outcomes. Previous work has examined the temporal and behavioral aspects of proximate fitness on life history outcomes particularly regarding highly perturbed environments (i.e., climate and land use change, resource extraction, agricultural erosion, etc.). My work focuses on the less examined spatial aspect of these perturbed environments. More specifically, this dissertation examines habitat selection and quality as the basis for understanding stress response (negative and positive feedback mechanisms) to environmental stressors within the larger context of regional or gamma (ɣ) biodiversity. Through the lens of environmental endocrinology, I examine patterns of glucocorticoid (GC) hormone differentiation spatially. I do this to understand how biotic and anthropogenic environmental stressors affect stress response in the American Crow (AMCR). This stress response could have an impact on human disease origins. I examined 13 sites throughout the State of Connecticut between 2019 and 2021, from very rural to very urbanized. I collected 153 opportunistic fecal samples of AMCR, then used radio immunoassay to characterize and quantify the samples as GC hormones, a key chemical constituent that reflects stress response in avian subjects. I then used a geographic information system (GIS) to plot various catchments for each sample centroid as notional representations of AMCR territories. I then overlayed 15 landcover types as biotic and anthropogenic environmental stressors (ESs). I used ordinary least squares linear regression for my initial analyses to evaluate the degree of validity of the ES–GC relationship at discrete locations where samples were taken and subsequently within varying sized territorial catchments. Finally, I reinterpreted a single constrained gravity model for the development of a habitat quality stress index (HQSI) to understand more dynamically how stress response is affected by movement around AMCR territories. Originally based on Newton’s law of universal gravitation I believe this is the first use of such a model in evaluating stress response via fecal GCs in an ecological setting across a spatial landscape. A major takeaway from these findings is that the historically understood linearly composed landscape gradient has a much greater extracellular or episodic or granular location-specific nature. Examining GIS raster imagery for instance, yields dramatic differentiation of land cover types over very small areas (\u3c0.1 km2) that indicates stress being applied in a highly stochastic manner. This coupled with the dramatic variation in GC levels around roost areas shows AMCR likely traveling significant distances over and through locations with various levels of environmental stressors to arrive at their roost sites each evening. Stress is mediated most effectively when there is consistency or linearity in its application, facilitating a rapid return to equilibrium. The extracellular nature of landcover examined showed a dramatic differentiation that stress response is unable to adjust toover time, without having a pathological response. This results in the extension or lengthening of the negative feedback response culminating in disequilibrium of a positive feedback response, and thereby reduction in proximate fitness and immunological resistance. AMCR, more so than many other taxa, is a highly social and adaptable avian species due to its higher level of cognition and neuroplastic nature (rapid flexibility and adaptation of response via its sophisticated central nervous system [CNS]). The AMCR populations in the roosts I observed thus favor urban locations. However, AMCR’s endocrine system adapts more slowly than their CNS (brain) to higher stress environments. Social cohesion thus outweighs homeostatic balance. In effect we would say that they are too smart for their own good