Converse College

To understand processes that govern the abundance and distribution of species, ecologists typically collect either long time series without surveying potential drivers or perform short-term experiments that may not scale up. We characterized the annual population dynamics of Arctia virginalis for 40 years and conducted experiments to examine the relative roles of abiotic conditions, host plants, predation, parasitoids, and viral infection. Rather than finding a single limiting factor, these factors were all important at some times or places. Annual densities varied by a thousand times and showed evidence of a regime shift around 2002, coincident with changing precipitation patterns. Wet sites and wet years supported higher densities, and precipitation interacted with most of the factors considered. Population control was context dependent, but water availability was generally the relevant context. Precipitation seems to be important for other Lepidoptera in western North America. Studies that include experimental tests of population drivers are required to manage insect populations.

Mixed cropping systems typically provide better natural pest control compared with monocultures, although the success varies depending on the crop and cultivar combinations. Understanding trait interactions that confer associational resistance (AR) to companion plants is key to optimizing these benefits. The Mesoamerican milpa system, known for its pest resistance, provides a model for studying these interactions. We tested two hypotheses to investigate whether access to extrafloral nectar (EFN) produced by Phaseolus vulgaris (common bean) can protect companion Zea mays (maize): (1) access to EFN enhances the survival and performance of a parasitoid wasp, leading to increased parasitism of fall armyworm (FAW) caterpillars on accompanying maize and reduced herbivory, and (2) bean plants can detect maize herbivore-induced plant volatiles (HIPVs) and respond by increasing EFN secretion. Controlled experiments demonstrated that wasps with access to EFN from bean plants lived longer, had higher fecundity, and parasitized more caterpillars on companion maize, thereby reducing herbivore damage. Additionally, caterpillar-damaged maize primed EFN secretion in companion bean plants via HIPVs. Our findings reveal a potentially important AR mechanism in the milpa, contributing to its reputed pest resistance. This understanding could inform the design of sustainable mixed cropping systems that enhance natural pest control.

Disruption of the human microbiome has emerged as a major contributing factor in the etiology of neurodegenerative disease. Previous work suggests a positive correlation between periodontal inflammation and Parkinson's disease. Here, we show that feeding C. elegans animals Porphorymonas gingivalis causes neurodegeneration that is not additive with neurodegeneration induced by the Parkinson's-associated protein, α-synuclein. In contrast, α-synuclein-expressing animals fed P. gingivalis show additional disruption in basal slowing, suggesting that P. gingivalis induces neurodegeneration while altering neuronal function of extant neurons. Though the mechanism is unclear, these results suggest a relationship between P. gingivalis and neurodegeneration that warrants further investigation.

ABSTRACT Frank B. Wilderson III’s theory of Afropessimism, as defined in his memoir, Afropessimism, is layered in various analyses. Some of these interpretations align with many Black thinkers throughout time whose work reflects the Black Diaspora and Afrofuturism. Other interpretations of Wilderson’s theory contrast the idea of Black progress. A closer look at poetic forms from Wilderson and other poets will provide a clearer understanding of what Afropessimism is and is not.

Introduction: Atrial fibrillation (AF) ablation for military personnel aims to provide therapeutic endpoints, recognizing that a subset of personnel require repeat ablation. Objective: This study aims to identify differences in characteristics and occupations of military members who received single versus repeat AF ablation. Further, we aim to understand the rates retention and deployment in those with single versus repeat AF ablation. Hypothesis: We hypothesize that there are increased rates of AF repeat ablations in personnel with risk factors for AF recurrence. Methods: Military personnel who underwent elective AF ablation between 2004 to 2019 were reviewed. Characteristics and military dispositions of personnel with repeated AF ablations were compared to those without. Results: 27 of 104 (26%) personnel received repeat AF catheter ablations on average 16.1±31 months after first ablation. There were no differences between age (34.5+9.5 vs 37.6+9.8 years, P=0.13), BMI (28.1±3.9 vs 28.7±3.4 kg/m2, P=0.48), presence of diastolic dysfunction (11.7% vs 7.4%, P=0.53), left atrial appendage emptying velocities (58.4+22 vs 59.7+23 cm/s, P=0.82), left atrial volume index (29.4+9.9 vs 29.6+8.8 ml/m2, P=0.87), left ventricular ejection fraction (60.4+6% vs 58.5+13%, P=0.31), CHA2DS2-VASc scores (0.37+0.6 vs 0.44+0.7, P=0.60) between those who received a single versus repeated AF ablation. Aviators (40%, 4/10) and healthcare workers (35%, 12/34) underwent repeated ablation at significantly increased rates when compared to 22% of administrators (4/18) and 10% of industrial workers (2/20), (P=0.032). Military retention rates were preserved in those requiring repeated ablation compared to those with single AF ablation (70%, 19/27 vs 78%, 60/77; P=0.60). Deployment rates were statistically similar between those requiring repeated AF ablation compared to single ablation (37%, 10/27 vs 43%, 33/77; P=0.43). Conclusions: Repeat AF catheter ablation rates in military tactical athletes may be driven by specific and individual occupational demands without increased traditional risk factors for AF recurrence. Military retention and deployment rates are preserved for those requiring repeated AF ablation compared to those with single ablation.

ABSTRACT Introduction: Internal Family Systems (IFS) Therapy has grown in popularity over the last several decades, demonstrating promising utility, especially in the treatment of mood disorders. However, IFS researchers have yet to explore its relevance specifically for Black populations in the United States. Objective: The present study investigated relationships between self-leadership, racial identity attitudes, race related stress, and mental health outcomes. Specifically, this study examined self-leadership as a potential mediator in the relationship between Black racial identity attitudes and the experience of race-related stress and mental health outcomes Methods: Participants (N = 79) were Black-identifying undergraduate students who completed self-report inventories. Mediation analyses were conducted using SPSS. Results: Self-leadership significantly predicted less severe negative mental health outcomes. Additionally, self-leadership fully mediated the relationship between the pre-encounter attitude of self-hatred and mental health outcomes, and self-leadership partially mediated the relationship between multiculturalist inclusive attitudes and stress due to institutional racism. Conclusion: Findings point to the potential utility of a major component of IFS, self-leadership, for future Black clinical populations.

The present study explored the adultification of young Black girls, specifically through the mythos of the fast-tailed girl, by examining the commentary on Twitter associated with the #SurvivingRKelly hashtag. Applying critical discourse analysis, three discursive themes emerged: (1) calling out the culture of accepting, (2) resistance through provocation and inquiry, and (3) challenging transgenerational dating. This study's results indicate the need for further research on the social construction of Black girlhood and how societal and cultural beliefs may serve as discursive mechanisms by which the adultification of young Black girls is perpetuated.