Restitution describes a functional relationship between the action potential duration (APD) and the preceding diastolic interval (DI). It plays an important role in the function of the heart and is believed to determine the stability of heart rhythms. We investigate the effects of various antiarrhythmic drugs on dynamic and standard (S1-S2) restitution properties of APD of ventricular cells by using a canine ventricular cell model. The restitution hypothesis suggests that the slope of the restitution curve governs the transition to alternans, believed to be a precursor to the development of ventricular arrhythmias, particularly ventricular fibrillation (VF). Our study examines the slope of these restitution curves for three classes of drug to determine whether they are proarrhythmic or antiarrhythmic and to test the hypothesis for the prediction of alternans.

Terror Management Theory suggests that individuals rely on worldview defenses to contend with mortality concerns. Similarly, religious individuals bolster their specific beliefs in order to defend against the awareness of death. Five studies examined the intersection between quest religiosity (e.g., individuals whose religious worldviews are to doubt and question), worldview defense, and existential anxieties. We hypothesized that quest individuals have weakened religious beliefs causing greater death thought accessibility. Additionally, quest individuals should display heightened secular worldview striving following mortality salience and less certainty in their own religiosity.

Introduction: When faced with a potential stressor, such as having a child with autism spectrum disorder (ASD), individuals use coping strategies to adjust to the situation. Certain coping strategies are more adaptive, such as positive reframing, which is related to lower levels of depression for parents of children with ASD (Hastings et al., 2005). However, there are differences in coping between mothers and fathers, and possibly between non-Hispanic White and Hispanic parents as a result of cultural differences (Hastings et al., 2005; Willis et al., 2016). Therefore, the goal of the current study was to investigate which adaptive coping strategies moderated the relationship between child symptom severity and parent mental health for both non-Hispanic White and Hispanic fathers of children with ASD.

Method: Participants were 75 fathers of children (M = 6.64 years, SD = 2.29 years) with ASD, and were either Hispanic (n = 43; M = 41.77 years, SD = 6.75) or non-Hispanic White (n = 31; M = 44.35 years, SD = 6.25). All fathers completed the current version of the Social Communication Questionnaire regarding their child’s symptom profile. They also completed the Center for Epidemiological Studies Depression Scale, a measure of adult depressive symptoms, and the Brief COPE, a measure of frequency of coping strategy use. Separate moderated regression models were entered in the PROCESS macro for SPSS for fathers of each ethnicity with each of the following coping strategies: positive reframing, active coping, planning, instrumental use of social support, and religious coping.

Results: For non-Hispanic White fathers, there was a significant interaction (i.e., moderation) between the effects of child symptom severity and use of positive reframing on the parent’s depressive symptoms, b = -.43 (SE = .17), p = .02. The interaction accounted for an additional 15.6% percent of variance in depressive symptoms. For fathers who infrequently used positive reframing, there was a significant positive relationship between child symptoms and parent depression, b = 1.01 (SE = .36), p = .01, but the relationship was non-significant for those who used high levels of positive reframing, p > .05. Moderation was also found with instrumental support coping, b = -.38 (SE = .11), p = .003, R2 = .26, and religious coping, b = -.46 (SE = .14), p = .004, R2 = .26. However, neither active coping nor planning coping were significant moderators for non-Hispanic White fathers, ps > .05. For Hispanic fathers, none of the aforementioned coping strategies served as a moderator of the relationship between child symptoms and parent depression, ps > .05.
Discussion: Results suggest that using adaptive coping strategies frequently serves as a protective factor for non-Hispanic White fathers’ mental health. Therefore, teaching those fathers adaptive coping strategies may improve their functioning. Previous interventions increased use of adaptive coping strategies in parents of children with ASD and may be applicable in the case of fathers, as well (Samadi, McConkey, & Kelly, 2013). However, it may be that there is some other factor besides coping strategy use, which serves as the best protective factor for Hispanic fathers. For instance, future research may investigate the importance of family functioning, given the importance of familism in Hispanic culture.

References:
Hastings, R. P., Kovshoff, H., Brown, T., Ward, N. J., Degli Espinosa, F., & Remington, B.
(2005). Coping strategies in mothers and fathers of preschool and school-age children
with autism. Autism, 9, 377-391. doi: 10.1177/1362361305056078

Samadi, S. A., McConkey, R., & Kelly, G. (2013). Enhancing parental well-being and coping
through a family-centred short course for Iranian parents of children with an autism
spectrum disorder. Autism, 17, 27-43. doi: 10.1177/1362361311435156

Willis, K., Timmons, L., Pruitt, M., Schneider, H. L., Alessandri, M., & Ekas, N. V. (2016). The
relationship between optimism, coping, and depressive symptoms in Hispanic mothers and fathers of children with autism spectrum disorder. Journal of Autism and Developmental Disorders, 46, 2427-2440. doi: 10.1007/s10803-016-2776-7

For several years, Texas horned lizards (Phrynosoma cornutum) in Kenedy and Karnes City (TX) have been the subject of ongoing studies at TCU. In the past decade lizards have disappeared from multiple locations in these towns, suggesting these populations are declining. To determine whether these populations have been stable or are declining in recent years, I used ArcGIS software to map GPS coordinates and calculate spatial statistics of horned lizards, their fecal pellets, and harvester ant mounds from 2013-2016. Stable spatial statistics across this time period should correlate with population stability at these sites.

Over the past century, millions of hectares of tropical rain forest have been cleared due to logging and agricultural endeavors. In addition to direct effects to terrestrial systems, conversion of land for agricultural use alters inputs to watersheds and has indirect effects on surrounding aquatic communities. Stream macroinvertebrates, which are often used as indicators of ecosystem health, can experience substantial changes in species composition as a result of these watershed alterations. We sampled macroinvertebrates from riffles and pools in a small stream with agricultural headwaters near the TCU El Jamaical Field Station in Costa Rica. We identified invertebrates to the lowest taxonomic level, and compared species abundance, richness, diversity, and evenness between riffles and pools. The high water quality and presence of bioindicator species suggest that this stream has been relatively unaffected by anthropogenic ecosystem alterations

Exposure to endocrine disrupting chemicals (EDCs), compounds that disrupt the normal hormone signaling pathways, can lead to a wide variety of negative outcomes in organisms. Although it has been shown that endocrine signaling systems interact with each other, research into the effects of EDCs has typically focused on a single endocrine axis independent of all others. This means that alterations in processes associated with nontargeted endocrine systems may be ignored. The interaction may also make it difficult to identify mechanisms of newly discovered EDCs. Because of these potential issues, it is important to understand the outcomes of endocrine axis interaction in organisms used as models for EDC testing. This experiment examined the effects of exposure to model thyroid disruptors, thyroxine (T4) and propylthiouracil (PTU), on reproductive function in the fathead minnow (Pimephales promelas). This species is a commonly used model organism but the outcomes of thyroid-reproductive system interaction are unknown. In addition to endpoints traditionally associated with the thyroid (e.g., thyroid related gene expression), this study included endpoints associated with overall reproductive function (e.g., number of eggs laid) and those more specific to the reproductive endocrine system (e.g., sex steroid related gene expression). It was found that model thyroid disruption lead to alterations in several thyroid and reproductive endpoints. Information on how thyroid disruption affects reproductive function in the fathead minnow will aid future experiments on EDC exposure in this species.

Carnivorous plants inhabit nutrient-poor environments, and they supplement nutrient uptake by capturing and absorbing nutrients from prey, such as insects. Like other plants, carnivorous plants are subject to loss of nutrient-containing tissues to herbivores. Because they occur in low-nutrient environments, tissue loss to herbivory can be expected to have a particularly strong negative effect on carnivorous plants. However, herbivory in carnivorous plants has not been well studied. In this study, we quantified tissue and nutrient losses sustained from herbivory by larvae of the specialist moth, Exyra semicrocea, in a population of pitcher plants, Sarracenia alata. We conducted field surveys, analyses of areal foliar damage, nutrient analyses, and feeding trials. In the study population, 83% (0.83 ± 0.033; mean ± SE) of pitchers were damaged by E. semicrocea. On average, approximately 15% of each affected pitcher was consumed before the larvae began feeding on another pitcher. Mean foliar nitrogen concentration was 1.19%, resulting in a mean nitrogen loss to consumption of 0.24 ± 0.041 mg per pitcher (N = 40). Mean foliar phosphorus concentration was 0.044%, resulting in a mean phosphorus loss per pitcher of 0.0086 ± 0.0015 mg (N = 37). In preliminary feeding trials, 4th and 5th instar larvae consumed 32 ± 3.8 mg /day and 33 ± 4.3 mg /day, respectively. Based on these consumption rates, estimated mean time spent feeding on a single pitcher was 2.5 ± 0.18 days (N = 95). Current studies are evaluating the impact of herbivory on reproductive output of these plants.

Mercury (Hg) is a toxic heavy metal that contaminates aquatic food webs. Methylated Hg can accumulate in fish, posing health hazards to fish-eating birds. All water bodies in the south central U.S. are contaminated with Hg but the level of contamination varies with ecoregion. Spatial patterns in the risk that Hg-contaminated fish pose to fish-eating birds is not understood. The objective of this study was to quantify Hg levels in a common fish species (bluegill, Lepomis macrochirus) and determine if the Hg contamination of bluegill poses a risk to a native fish-eating bird (the double-crested cormorant, Phalacrocorax auritus) in 14 USEPA level III ecoregions in six states in the south central U.S. We used the National Descriptive Model for Mercury in Fish to estimate the concentration of Hg in 8-cm total length bluegill in 835 sites. We then compared those Hg concentrations to the cormorant wildlife value (WV), an estimate of the minimum concentration of Hg in the diet of the consumer to cause physiologically significant doses. The concentration of Hg in bluegill exceeded the WV in 38% of sampling sites across the region. Within the 14 ecoregions the proportion of sampling sites that exceeded the wildlife value ranged from 7% to 77%. Ecoregions with highest Hg deposition from the atmosphere adjusted for conifer coverage had the highest proportion of sampling sites exceeding the WV.

The United States requires that whole effluent and chemicals be tested for aquatic toxicity using the fathead minnow larval growth and survival (LGS) test. While the LGS test has been effective for determining acute and chronic aquatic toxicity, a fathead minnow fish embryo toxicity (FET) test has been proposed as a refinement to the LGS as younger organisms are thought to experience less stress during toxicant exposure. Presently, the FET test protocol does not include endpoints that allow for the prediction of non-lethal adverse outcomes or chronic toxicity. This limits its utility relative to other test types. This study investigated the utility of sublethal endpoints related to cardiovascular function and development (e.g., heart rate, pericardial area, and cardiovascular related genes) as additional FET test metrics. FET tests were run with four model toxicants: 3,4 –dichloroaniline, sodium chloride, cadmium, and triclosan. Heart rate was evaluated at 76 hpf, while pericardial area was assessed at 120 hpf. Hatched larvae were sampled at the conclusion of the tests (120hpf) for gene expression analysis. Pericardial area was identified as the most sensitive sub-lethal endpoint, although alterations were also seen in the other metrics investigated. These alterations suggest that sublethal endpoints related to cardiovascular function and morphology may be useful for estimating non-lethal adverse effects and chronic toxicity. Future studies aimed at linking alterations in these endpoints to longer term adverse impacts are needed to fully describe the predictive power of these metrics in whole effluent and chemical toxicity testing.

Wind energy is a renewable resource with many environmental benefits. However, one environmental impact from wind energy is on bats, because bats can be killed when they fly into the path of spinning turbine blades. Estimates of bat fatalities at wind facilities across the U.S. exceed 500,000 per year. One potential way to reduce bat fatalities at wind facilities is with acoustic deterrents. These devices, including the newly designed acoustic deterrent tested during this study, produce sound which is intended to disrupt bat echolocation. We used video cameras to evaluate bat activity and behavioral responses to the acoustic deterrent at a wind facility in north-central Texas. The acoustic deterrent reduced the level of bat activity by up to 90%, and also altered the flight behavior of bats. Our data indicate that this acoustic deterrent could significantly reduce bat fatalities at wind facilities once the devices are installed on turbines.