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