PROJECT SUMMARY/ABSTRACT The purpose of this Diversity Supplement is to provide Mr. Jeremy Delgadillo, a Mexican American first- generation college graduate and first-year PhD student, research experience and training to promote his career development. This supplement will be nested in Dr. Pariya Wheeler’s R21 grant “Testing the Efficacy and Mechanisms of an Adapted Resilience Building Intervention in People Aging with HIV” (R21 AG076377- 01A1). The goal of the parent study is to test an adapted resilience intervention among 100 older PLHIV. This proposal is particularly innovative due to its use of the real-time ESM approach to assess intervention efficacy and mechanisms. Mr. Delgadillo will be positioned to leverage the rich baseline dataset from this parent R21 study to examine several important temporal associations between stress reactivity, resilience resources, and health outcomes among older PLWH. The baseline data collection will be complete within 1 year, allowing Mr. Delgadillo to engage in data analysis and dissemination in Year 2. Specifically, he will have baseline data on 100 PLHIV, which includes an extensive assessment to measure sociodemographics and stressful life events/trauma, health variables (e.g., comorbidities, HIV medical parameters), psychological functioning, and HIV treatment management. Furthermore, the baseline data will also include a 14-day ESM protocol that queries participants on stressful events, use of resilience resources, and affect. Importantly, given the diverse sample of ~50% African American/Black PLHIV that will be enrolled in this R21, Mr. Delgadillo will be well positioned to examine racial differences that may emerge in the findings, which aligns with his interests in racial and health disparities. Together, this rich dataset will allow Mr. Delgadillo to examine the following aims: AIM 1: To examine person-factors (e.g., race, SES, personality) as well as factors related to lifetime stress (e.g., lifetime adversity and adverse childhood events) and momentary stress (e.g., severity) as predictors of use of resilience resources (both global use and use of specific resources) following stressors. AIM 2: To examine whether specific resilience resources better predict stress reactivity, and whether resilience resources in turn predict better health outcomes (i.e., psychological functioning and HIV outcomes). Impact: These research findings will fill a significant gap in the field on understanding how PLWH react following stressors and how these behaviors impact health outcomes, which will inform the development of both prevention and intervention strategies. Importantly, these results will supplement and complement the results from the primary aims of the parent study that will assess intervention efficacy and mechanisms. The research training and career development plan proposed by Mr. Delgadillo and his mentoring team will ensure he is able to succeed in his future career, and will also prepare him to s...