Background: Young sexual minority men in the United States have a high incidence rate of HIV infection. Early intervention among this group, that is timed to precede or coincide with sexual initiation, is of critical importance to prevent HIV infection. Despite this, there are very few published randomized controlled efficacy trials testing interventions to reduce sexual vulnerability for HIV acquisition among racially/ethnically diverse, very young, sexual minority men (aged ≤18 years). This paper describes the design of a mobile app-based intervention trial to reduce sexual risk for HIV acquisition and promote health protection in this group. Methods: This study is a randomized controlled trial of an mHealth-based HIV prevention intervention, MyPEEPS Mobile, among diverse sexual minority cisgender young men, aged 13-18 years. The mobile intervention was adapted from a prior group-based intervention curriculum with evidence of efficacy, designed to be specific to the risk contexts and realities of young sexual minority men, and to include psychoeducational and skill-building components with interactive games and activities. Participants are recruited locally within four regional hubs

BackgroundMobile health (mHealth) apps have the potential to be a useful mode of delivering HIV prevention information, particularly for young men (13-24 years) who account for 21% of new HIV diagnoses in the United States. We translated an existing evidence-based, face-to-face HIV prevention curriculum into a portable platform and developed a mobile Web app: MyPEEPS Mobile.ObjectiveThe purpose of this study was to assess the usability of MyPEEPS Mobile from both expert and end user perspectives.MethodsWe conducted a heuristic evaluation with five experts in informatics to identify violations of usability principles and end user usability testing with 20 young men aged 15 to 18 years in New York, NY, Birmingham, AL, and Chicago, IL to identify potential obstacles to their use of the app.ResultsMean scores of the overall severity of the identified heuristic violations rated by experts ranged from 0.4 and 2.6 (0=no usability problem to 4=usability catastrophe). Overall, our end users successfully completed the tasks associated with use case scenarios and provided comments/recommendations on improving usability of MyPEEPS Mobile. The mean of the overall Post-Study System Usability Questionnaire scores rated by the end users was 1.63 (SD 0.65), reflecting strong user acceptance of the app.ConclusionsThe comments made by experts and end users will be used to refine MyPEEPS Mobile prior to a pilot study assessing the acceptability of the app across diverse sexual minority young men in their everyday lives.

There is a dearth of evidence-based HIV prevention interventions for very young men who have sex with men (YMSM) ages 13–18 years, at high risk for HIV. We adapted the MyPEEPS intervention—an evidence-based, group-level intervention—to individual-level delivery by a mobile application. We used an expert panel review, in-depth interviews with YMSM (n = 40), and weekly meetings with the investigative team and the software development company to develop the mobile app. The expert panel recommended changes to the intervention in the following areas: (1) biomedical interventions, (2) salience of intervention content, (3) age group relevance, (4) technical components, and (5) stigma content. Interview findings reflected current areas of focus for the intervention and recommendations of the expert panel for new content. In regular meetings with the software development firm, guiding principles included development of dynamic content, while maintaining fidelity of the original curriculum and shortening intervention content for mobile delivery.

Vertical soil moisture profiles based on the principle of maximum entropy (POME) were validated using field and model data and applied to guide an irrigation cycle over a maize field in north central Alabama (USA). The results demonstrate that a simple two-constraint entropy model under the assumption of a uniform initial soil moisture distribution can simulate most soil moisture profiles that occur in the particular soil and climate regime that prevails in the study area. The results of the irrigation simulation demonstrated that the POME model produced a very efficient irrigation strategy with minimal losses (about 1.9% of total applied water). However, the results for finely-textured (silty clay) soils were problematic in that some plant stress did develop due to insufficient applied water. Soil moisture states in these soils fell to around 31% of available moisture content, but only on the last day of the drying side of the irrigation cycle. Overall, the POME approach showed promise as a general strategy to guide irrigation in humid environments, such as the Southeastern United States.

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