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Through field survey and laboratory analysis, we examined the composition and fractal features of soil micro-aggregates in different types of treefall gaps and microsites (pit bottom and mound top) in broad-leaved Korean pine forest and spruce-fir-Korean pine forest. Results showed that the contents of soil microaggregates under the classes of 0.25-2 mm and 0.05-0.25 mm were higher in both forest types, ranging from 25.7% to 50.7% and from 27.0% to 42.8%, respectively, and that of <0.002 mm was the lowest, ranging from 4.4% to 8.9%. In the pit bottom and mound top of gaps, soil bulk density was higher in both forest types. Soil nutrient content in mound top was higher than that in pit bottom and was higher in broad-leaved Korean pine forest than spruce-fir-Korean pine forest. Soil microaggregates of <0.002 mm had no correlation with soil physical and chemical properties, whereas that of 0.25-2 mm and 0.002-0.02 mm had significantly positive and negative correlation with soil non-capillary porosity, total porosity, aeration porosity, organic matter, total phosphorus, total nitrogen and organic carbon, respectively. On the whole, soil fractal dimension (D) and the proportion of characteristic soil micro-aggregates (PCM) in broad-leaved Korean pine forest were larger than those in spruce-fir-Korean pine forest, and the ratio of soil microaggregates diameter (RMD) in mound top and pit bottom was increased in two forest types. Soil D and PCM had no significant correlation with soil physical and chemical properties, while RMD was negatively correlated with capillary porosity, total porosity, soil bulk density and aeration porosity. In two forest types, the formation of mound and pit microsites could decrease the larger size micro-aggregates and the stability of soil micro-aggregate, increase soil D and PCM, and signifi-cantly increase RMD. RMD could be used as a quantitative index of soil physical and chemical properties in pit and mound microsites of forest.

An emerging HIV epidemic can be seen among men who have sex with men (MSM) in Vietnam. There are currently no evidence-based behavioral sexual risk reduction interventions for MSM in this setting. Between October 2012 and June 2013, 100 high-risk MSM from Ho Chi Minh City were enrolled in an open pilot trial to assess feasibility and acceptability of a group-based, manualized sexual risk reduction intervention, and to preliminarily examine changes in primary and secondary outcomes. Participants completed a behavioral assessment battery and HIV testing at baseline, 3, and 6 months post-baseline. Over 80.0 % of the sample was <25 years old and 77.0 % identified as Bong kin ("hidden," masculine-appearing). Feasibility and acceptability of the program was evidenced by 87.0 % retention for the intervention sessions, 78.0 % completion of the 6 month assessment, and positive responses on evaluation forms and qualitative exit interviews. There was a decline in the number of condomless anal sex acts from baseline (6.32) to 3 month (2.06) and 6 month (2.49) follow-up (p < .0001). These data support the need for further testing of this group-based, behavioral HIV prevention intervention to reduce sexual risk behavior among MSM in Vietnam in a randomized controlled efficacy trial.

An emerging HIV epidemic can be seen among men who have sex with men (MSM) in Vietnam, with prevalence as high as 18%. Transactional sex represents a risk factor for HIV transmission/acquisition among MSM globally, particularly in urban contexts, but remains largely underinvestigated in Ho Chi Minh City (HCMC), Vietnam. In 2010, 23 MSM who reported exchanging sex for money in the last month completed a brief survey and semistructured qualitative interview at The Life Centre, a non-governmental organization in HCMC, to assess sociodemographics, individual- and structural-level HIV risk factors and explore acceptable future prevention interventions. Participants' mean age was 24 years. Equal proportions of respondents self-identified as heterosexual/straight, homosexual/gay, and bisexual. Participants had a mean of 158 male clients in the past year, with a median of 60 male clients in the past year (interquartile range [IQR]=70) and reported inconsistent condom use and inaccurate perceptions of HIV risk. Nearly half of the sample reported engaging in unprotected anal sex with a male partner in the past 12 months and one-third with a male client. Major themes that emerged for HIV prevention interventions with male sex workers were those that: (1) focused on individual factors (drug and alcohol use, barriers to condom use, knowledge of asymptomatic STIs, enhancement of behavioral risk-reduction skills, and addressing concomitant mental health issues); (2) incorporated interpersonal and relational contexts (led by peer educators, built interpersonal skills, attended to partner type and intimacy dynamics); and (3) considered the exogenous environments in which individual choices/relationships operate (stigma of being MSM in Vietnam, availability of alternative economic opportunities, and varied sexual venues). HIV prevention efforts are needed that address the specific needs of MSM who engage in transactional sex in HCMC. Universally, MSM endorsed HIV prevention interventions, suggesting a need and desire for efforts in this context.