Correlations between the interfacial chemistry and current-voltage behavior of n-GaAs/liquid junctions

Correlations between the surface chemistry of etched, (100) oriented n-GaAs electrodes and their subsequent photoelectrochemical behavior have been probed by high-resolution x-ray photoelectron spectroscopy. GaAs photoanodes were chemically treated to prepare either an oxide-free near stoichiometric surface, a surface enriched in zero-valent arsenic (As0), or a substrate-oxide terminated surface. The current-voltage (I-V) behavior of each surface type was subsequently monitored in contact with several electrolytes

Fabrication of minority-carrier-limited n-Si/insulator/metal diodes

A photoelectrochemical anodization technique has been used to fabricate n-Si/insulator/metal (MIS) diodes with improved electrical properties. MIS structures fabricated with Au have provided the first experimental observation of a solid-state n-Si surface barrier device whose open circuit voltage Voc is controlled by minority-carrier bulk diffusion/recombination processes. For these diodes, variation of the minority-carrier diffusion length and majority-carrier dopant density produced changes in Voc that were in accord with bulk diffusion/recombination theory. Additionally, the variation in Voc in response to changes in the work function of the metal overlayer indicated that these MIS devices were not subject to the Fermi level pinning restrictions observed for n-Si Schottky structures. X-ray photoelectron spectroscopic characterization of the anodically grown insulator indicated 8.2±0.9 Å of a strained SiO2 layer as the interfacial insulator resulting from the photoanodization process

Effectiveness of Health Education Teachers and School Nurses Teaching Sexually Transmitted Infections/ Human Immunodeficiency Virus Prevention Knowledge and Skills in High School

BACKGROUND- We examined the differential impact of a well-established human immunodeficiency virus (HIV)/sexually transmitted infections (STIs) curriculum, Be Proud! Be Responsible!, when taught by school nurses and health education classroom teachers within a high school curricula. METHODS- Group-randomized intervention study of 1357 ninth and tenth grade students in 10 schools. Twenty-seven facilitators (6 nurses, 21 teachers) provided programming; nurse-led classrooms were randomly assigned. RESULTS- Students taught by teachers were more likely to report their instructor to be prepared, comfortable with the material, and challenged them to think about their health than students taught by a school nurse. Both groups reported significant improvements in HIV/STI/condom knowledge immediately following the intervention, compared to controls. Yet, those taught by school nurses reported significant and sustained changes (up to 12 months after intervention) in attitudes, beliefs, and efficacy, whereas those taught by health education teachers reported far fewer changes, with sustained improvement in condom knowledge only. CONCLUSIONS- Both classroom teachers and school nurses are effective in conveying reproductive health information to high school students; however, teaching the technical (eg, condom use) and interpersonal (eg, negotiation) skills needed to reduce high-risk sexual behavior may require a unique set of skills and experiences that health education teachers may not typically have

Novel Interventions for HIV Self-Management in African American Women: A Systematic Review of mHealth Interventions

The purpose of this systematic review was to assess the quality of interventions using mobile health (mHealth) technology being developed for and trialed with HIV-infected African American (AA) women. We aimed to assess rigor and to ascertain if these interventions have been expanded to include the broad domain of self-management. After an extensive search using the PRISMA approach and reviewing 450 records (411 published studies and 39 ongoing trials atclinicaltrials.gov), we found little completed research that tested mHealth HIV self-management interventions for AA women. Atclinicaltrials.gov, we found several mHealth HIV intervention studies designed for women in general, forecasting a promising future. However, most studies were exploratory in nature and focused on a single narrow outcome, such as medication adherence. Given that cultural adaptation is the key to successfully implementing any effective self-management intervention, culturally relevant, gender-specific mHealth interventions focusing on HIV-infected AA women are warranted for the future

Climate Stories: South Carolina, Volume 1

In this volume, you will hear from South Carolina residents about how they have been sensing climate change throughout their lifetimes. All stories have been anonymized with the use of pseudonyms, except where participants asked for their story to be associated with their name

The influence of dissolved oxygen on winter habitat selection by largemouth bass: an integration of field biotelemetry studies and laboratory experiments

In this study, field biotelemetry and laboratory physiology approaches were coupled to allow understanding of the behavioral and physiological responses of fish to winter hypoxia. The biotelemetry study compared dissolved oxygen levels measured throughout the winter period with continually tracked locations of nine adult largemouth bass obtained from a whole‐lake submerged telemetry array. Fish habitat usage was compared with habitat availability to assess whether fish were selecting for specific dissolved oxygen concentrations. The laboratory study examined behavioral and physiological responses to progressive hypoxia in juvenile largemouth bass acclimated to winter temperatures. Results from the dissolved oxygen measurements made during the biotelemetry study showed high variance in under‐ice dissolved oxygen levels. Avoidance of water with dissolved oxygen less than 2.0 mg/L by telemetered fish was demonstrated, but significant use of water with intermediate dissolved oxygen levels was also found. Results from the lab experiments showed marked changes in behavior (i.e., yawning and vertical movement) at less than 2.0 mg/L of dissolved oxygen but no change in tissue lactate, an indicator of anaerobic metabolism. Combined results of the biotelemetry and laboratory studies demonstrate that a dissolved oxygen content of 2.0 mg/L may be a critical threshold that induces behavioral responses by largemouth bass during the winter. In addition, the use by fish of areas with intermediate levels of dissolved oxygen suggests that there are multiple environmental factors influencing winter behavior."This project was supported by LotekWireless, and funding was provided by Queen’s University, the Illinois Natural History Survey, Canada Foundation for Innovation, Carleton University, and the Natural Sciences and Engineering Research Council.

The Effect of Acoustic Forcing on Instabilities and Breakdown in Swept-Wing Flow over a Backward-Facing Step

Instability interaction and breakdown were experimentally investigated in the flow over a swept backward-facing step. Acoustic forcing was used to excite the Tollmien-Schlichting (TS) instability and to acquire phase-locked results. The phase-averaged results illustrate the complex nature of the interaction between the TS and stationary cross flow instabilities. The weak stationary cross flow disturbance causes a distortion of the TS wavefront. The breakdown process is characterized by large positive and negative spikes in velocity. The positive spikes occur near the same time and location as the positive part of the TS wave. Higher-order spectral analysis was used to further investigate the nonlinear interactions between the TS instability and the traveling cross flow disturbances. The results reveal that a likely cause for the generation of the spikes corresponds to nonlinear interactions between the TS, traveling cross flow, and stationary cross flow disturbances. The spikes begin at low amplitudes of the unsteady and steady disturbances (2-4% U (sub e) (i.e. boundary layer edge velocity)) but can achieve very large amplitudes (20-30 percent U (sub e) (i.e. boundary layer edge velocity)) that initiate an early, though highly intermittent, breakdown to turbulence

Taking Be proud! Be responsible! to the Suburbs: A Replication Study

CONTEXT: An important phase of HIV prevention research is replicating successful interventions with different groups and in different settings. METHODS: Be Proud! Be Responsible!, a successful intervention originally targeting black urban males and carried out in nonschool settings, was presented in health classes at urban and suburban schools with diverse student bodies. A group-randomized intervention study, which included 1,357 ninth and 10th graders from 10 paired schools in a Midwestern metropolitan area, was conducted in 2000-2002. Half the schools received the intervention, and half received a general health promotion program. Students\u27 reports of their sexual behavior and selected cognitive mediators were analyzed immediately following the programs and four and 12 months later. RESULTS: Compared with students who received the control curriculum, students exposed to the intervention reported significantly greater knowledge of HIV, other STDs and condoms; greater confidence in their ability to control sexual impulses, to use condoms and to negotiate the use of condoms; and stronger intentions to use condoms. Stratified analyses revealed that the strongest intervention impacts were on knowledge and efficacy among males and students attending suburban schools. The intervention had no impact on sexual initiation, frequency of intercourse or condom use. CONCLUSIONS: Schools are a logical and viable setting for the dissemination and acquisition of information about HIV, including prevention strategies. However, the behavioral impact of an intervention may not be easily transferable when the program is taught outside a carefully controlled, nonschool setting