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OBJECTIVES: Injecting drug use (IDU) remains an actual risk variable in human immunodeficiency virus (HIV) infection in most ethnic populations, and the association between actual risk and individual perception of HIV risk varies across studies and samples. This study aimed to examine the relationship between IDU and HIV risk perception among Mexican Americans residing in Rio Grande Valley, South Texas. STUDY DESIGN: A cross-sectional study of IDU as a predictor of HIV risk perception. METHODS: Two hundred and seventy-five participants [IDUs 11.9%, non-IDUs 88.1%] were assessed for an association between IDU and individual risk perception for HIV infection, as well as history of drug use and HIV risk perception, using Chi-squared statistic for independence and a logistic regression model for the prevalence odds ratio (POR). RESULTS: There was no statistically significant difference between IDUs and non-IDUs with respect to the sociodemographic variables, except for income and gender (P<0.05). The results indicated a statistically significant decrease in HIV risk perception among IDUs compared with non-IDUs, after adjustment for age, gender, sexual preference, history of drug use and marital status [POR 0.26, 95% confidence intervals (CI) 0.11-0.65]. Likewise, history of drug use was associated with decreased HIV risk perception (POR 0.44, 95% CI 0.22-0.98). CONCLUSIONS: These results suggest an inverse correlation between actual risk of HIV infection, such as IDU, and HIV risk perception. Therefore, assessment of HIV risk perception, which is a significant determinant of behaviour change, is essential to reduce the prevalence of HIV infection in the targeted population.
Asunto(s)
Infecciones por VIH/etiología , Infecciones por VIH/psicología , Americanos Mexicanos/psicología , Abuso de Sustancias por Vía Intravenosa/complicaciones , Abuso de Sustancias por Vía Intravenosa/psicología , Adulto , Estudios Transversales , Femenino , Humanos , Masculino , Percepción , Religión , Factores de Riesgo , Conducta Sexual , Factores Socioeconómicos , TexasRESUMEN
Conversion to cattle pasture is the most common fate of the ≈426,000 km2 of tropical forest that has been deforested in the Brazilian Amazon. Yet little is known about the biomass, C, nutrient pools, or their responses to the frequent fires occurring in these pastures. We sampled biomass, nutrient pools and their losses or transformation during fire in three Amazonian cattle pastures with typical, but different, land-use histories. Total aboveground biomass (TAGB) ranged from to 53 to 119 Mg ha-1. Residual wood debris from the forests that formally occupied the sites composed the majority of TAGB (47-87%). Biomass of fine fuels, principally pasture grasses, was ≈16-29 Mg ha-1. Grasses contained as much as 52% of the aboveground K pool and the grass and litter components combined composed as much as 88% of the aboveground P pool. Fires consumed 21-84% of the TAGB. Losses of C to the atmosphere ranged from 11 to 21 Mg ha-1 and N losses ranged from 205 to 261 kg ha-1. Losses of S, P, Ca, and K were <33 kg ha-1. There were no changes in surface soil (0-10 cm) nutrient concentration in pastures compared to adjacent primary forests. Fires occur frequently in cattle pastures (i.e., about every 2 years) and pastures are now likely the most common type of land burned in Amazonia. The first 6 years of a pastures existence would likely include the primary forest slash fire and three pasture fires. Based upon our results, the cumulative losses of N from these fires would be 1935 kg ha-1 (equivalent to 94% of the aboveground pool of primary forest). Postfire aboveground C pools in old pastures are as low as 3% of those in adjacent primary forest. The initial primary forest slash fire and the repeated fires occurring in the pastures result in the majority of aboveground C and nutrient pools being released via combustion processes rather than decomposition processes.
RESUMEN
Deforestation in the Brazilian Amazon has resulted in the conversion of >230,000 km2 of tropical forest, yet little is known on the quantities of biomass consumed or the losses of nutrients from the ecosystem. We quantified the above-ground biomass, nutrient pools and the effects of biomass burning in four slashed primary tropical moist forests in the Brazilian Amazon. Total above-ground biomass (TAGB) ranged from 292 Mg ha-1 to 436 Mg ha-1. Coarse wood debris (>20.5 cm diameter) was the dominant fuel component. However, structure of the four sites were variable. Coarse wood debris comprised from 44% to 69% of the TAGB, while the forest floor (litter and rootmat) comprised from 3.7 to 8.0% of the TAGB. Total biomass consumption ranged from 42% to 57%. Fires resulted in the consumption of >99% of the litter and rootmat, yet <50% of the coarse wood debirs. Dramatic losses in C, N, and S were quantified. Lesser quantities of P, K, and Ca were lost by combustion processes. Carbon losses from the ecosystem were 58-112 Mg ha-1. Nitrogen losses ranged from 817 to 1605 kg ha-1 and S losses ranged from 92 to 122 kg ha-1. This represents losses that are as high as 56%, 68%, and 49% of the total above-ground pools of these nutrients, respectively. Losses of P were as high as 20 kg ha-1 or 32% of the above-ground pool. Losses to the atmosphere arising from primary slash fires were variable among sites due to site differences in concentration, fuel biomass, and fuel structure, climatic fluctuations, and anthropogenic influences. Compared to fires in other forest ecosystems, fires in slashed primary tropical evergreen forests result in among the highest total losses of nutrients ever measured. In addition, the proportion of the total nutrient pool lost from slash fires is higher in this ecosystem compared to other ecosystems due to a higher percentage of nutrients stored in above-ground biomass.
Asunto(s)
Úlcera de la Pierna/etiología , Infecciones por Mycobacterium , Preescolar , Humanos , Rodilla , Masculino , PerúRESUMEN
The importance of bilateral ambloyopia as a cause of a poor visual result following cataract extraction in West Indians is assessed. It is submitted that this disorder is more common than previously considered and an incidence of 5 to 7 per cent among 50 to 80-year-old Jamaicans undergoing cataract extraction is suggested. Factors influencing this figure are postulated. Certain clinical aspects of the condition are considered. (AU)