The development of a personnel dosimetry system for apollo eleventh quarterly progress report

Personnel dosimetry system for Apoll

Measurements of nonmethane hydrocarbons in 28 United States cities

Between 1999 and 2005 a sampling campaign was conducted to identify and quantify the major species of atmospheric nonmethane hydrocarbons (NMHCs) in United States cities. Whole air canister samples were collected in 28 cities and analyzed for methane, carbon monoxide (CO) and NMHCs. Ambient mixing ratios exhibited high inter- and intra-city variability, often having standard deviations in excess of 50% of the mean value. For this reason, ratios of individual NMHC to CO, a combustion tracer, were examined to facilitate comparison between cities. Ratios were taken from correlation plots between the species of interest and CO, and most NMHCs were found to have correlation coefficients (r2) greater than 0.6, particularly ethene, ethyne and benzene, highlighting the influence of vehicular emissions on NMHC mixing ratios. Notable exceptions were the short-chain alkanes, which generally had poor correlations with CO. Ratios of NMHC vs. CO were also used to identify those cities with unique NMHC sources. © 2007 Elsevier Ltd. All rights reserved

Condom use and the risk of HIV infection: who is being protected?

A study/survey done on condom use among Zimbabwean men in Zimbabwe.Descriptive baseline data at enrolment into a cohort of male factory workers who were tested for HIV serology and monitored for sero-con version over time, were analysed for condom use. At recruitment, the 1 146 men were asked about their sexual behaviour, history of sexually transmitted diseases (STDs), condom use and circumstances under which condoms were used. HIV seroprevalence in the cohort was 18,2 pc. Self reported use of condoms was low, with only 5 pc of the men reporting using them all the time. Forty four pc reported that they had never used a condom, 11,5 pc tried a condom only once, and 30,5 pc used condoms less than half the time. HIV positive men were more likely (Odds Ratio [OR]= 2,2 95 pc Cl: 1,3 — 3,3) to use condoms than those who tested negative. Men using a condom more than once were younger and had more education (p values < 0,0005). Univariate analysis showed that men with self reported risk factors for HIV infection were more likely to use condoms. Significantly more condom users reported paying for sex, multiple sex partners or (for married men) a girlfriend (p < 0,005). Condom users also more often had a history of genital ulcers, urethral discharge or other STDs. Few married men (24 pc) reported using a condom with their wives. Condom use was more commonly reported with commercial sex workers (44 pc) or other extramarital partners (36 pc). Some risk factors for HIV infection were also present amongst men who reported that they did not use condoms. Independent determinants of condom use identified by stepwise logistic regression analysis included young age, having a girlfriend (OR = 2,2; 95 pc Cl: 1,47 — 3,3), number of sex partners in the last year (OR = 1,27; 95 pc Cl: 1,06 —1,51 per partner), and paying for sex in the preceding year (OR = 1,74; 95 pc Cl: 1,06 — 2,83). The results show that men use condoms with partners considered risky, such as prostitutes or girlfriends but use condoms less often with their wives. The results underscore theneedfor health education for behavioural change that promotes universal, consistent use of condoms or monogamous partnership

NMHCs and halocarbons in Asian continental outflow during the Transport and Chemical Evolution over the Pacific (TRACE-P) Field Campaign: Comparison with PEM-West B

We present an overview of the spatial distributions of nonmethane hydrocarbons (NMHCs) and halocarbons observed over the western north Pacific as part of the NASA GTE Transport and Chemical Evolution over the Pacific (TRACE‐P) airborne field campaign (February–April 2001). The TRACE‐P data are compared with earlier measurements from the Pacific Rim during the Pacific Exploratory Mission‐West B (PEM‐West B), which took place in February–March 1994, and with emission inventory data for 2000. Despite the limited spatial and temporal data coverage inherent to airborne sampling, mean levels of the longer‐lived NMHCs (including ethane, ethyne, and benzene) were remarkably similar to our results during the PEM‐West B campaign. By comparison, mixing ratios of the fire extinguisher Halon‐1211 (CF2ClBr) increased by about 50% in the period between 1994 and 2001. Southern China (south of 35°N), and particularly the Shanghai region, appears to have been a substantial source of Halon‐1211 during TRACE‐P. Our previous analysis of the PEM‐West B data employed methyl chloroform (CH3CCl3) as a useful industrial tracer. However, regulations have reduced its emissions to the extent that its mixing ratio during TRACE‐P was only one‐third of that measured in 1994. Methyl chloroform mixing ratio “hot spots,” indicating regions downwind of continuing emissions, included outflow from the vicinity of Shanghai, China, but particularly high emission ratios relative to CO were observed close to Japan and Korea. Tetrachloroethene (C2Cl4) levels have also decreased significantly, especially north of 25°N, but this gas still remains a useful indicator of northern industrial emissions. Methyl bromide (CH3Br) levels were systematically 1–2 pptv lower from 1994 to 2001, in accord with recent reports. However, air masses that had been advected over Japan and/or South Korean port cities typically exhibited elevated levels of CH3Br. As a consequence, emissions of CH3Br from Japan and Korea calculated employing CH3Br/CO ratios and scaled to CO emission inventory estimates, were almost as large as for all of south China (south of 35°N). Total east Asian emissions of CH3Br and CH3Cl were estimated to be roughly 4.7 Gg/yr and 167 Gg/yr, respectively, in 2001

Large-scale latitudinal and vertical distributions of NMHCs and selected halocarbons in the troposphere over the Pacific Ocean during the March-April 1999 Pacific Exploratory Mission (PEM-Tropics B)

Nonmethane hydrocarbons (NMHCs) and selected halocarbons were measured in whole air samples collected over the remote Pacific Ocean during NASA's Global Tropospheric Experiment (GTE) Pacific Exploratory Mission-Tropics B (PEM-Tropics B) in March and early April 1999. The large-scale spatial distributions of NMHCs and C2Cl4 reveal a much more pronounced north-south interhemispheric gradient, with higher concentrations in the north and lower levels in the south, than for the late August to early October 1996 PEM-Tropics A experiment. Strong continental outflow and winter-long accumulation of pollutants led to seasonally high Northern Hemisphere trace gas levels during PEM-Tropics B. Observations of enhanced levels of Halon 1211 (from developing Asian nations such as the PRC) and CH3Cl (from SE Asian biomass burning) support a significant southern Asian influence at altitudes above 1 km and north of 10° N. By contrast, at low altitude over the North Pacific the dominance of urban/industrial tracers, combined with low levels of Halon 1211 and CH3Cl, indicate a greater influence from developed nations such as Japan, Europe, and North America. Penetration of air exhibiting aged northern hemisphere characteristics was frequently observed at low altitudes over the equatorial central and western Pacific south to ∼5° S. The relative lack of southern hemisphere biomass burning sources and the westerly position of the South Pacific convergence zone contributed to significantly lower PEM-Tropics B mixing ratios of the NMHCs and CH3Cl south of 10° S compared to PEM-Tropics A. Therefore the trace gas composition of the South Pacific troposphere was considerably more representative of minimally polluted tropospheric conditions during PEM-Tropics B. Copyright 2001 by the American Geophysical Union

HIV seroconversion among factory workers in Harare: who is getting newly infected?

A clinical report on the impact of HIV/AIDS among factory workers in Zimbabwe's industrial areas of Harare.It was estimated that by the of 1996 more than 8.4 million AIDS cases had occurred worldwide.1 Because of the long and variable duration between infection with the human immunodeficiency virus (HIV) and the ultimate development of AIDS, a more useful indication of current trends in the epidemic is the number of new infections with HIV. Twenty eight million people from 190 countries across the world were HIV positive by mid 1996.Composed of distinct epidemics, each with its own features, degree and extent, the pandemic has had a disproportionately severe impact on the developing world. Despite wide information on HIV prevention, 3.1 million new infections occurred during 1996. Up to 93% of the HIV infections recorded in 1996 were from developing countries with 68% from sub-Saharan Africa.2 Developing countries, who have weaker economic structures, continue to bear the greatest burden of HIV infections. HIV infection appears be spreading much faster in Southern Africa than anywhere else

The Danish HIV Birth Cohort (DHBC) - a nationwide, prospective cohort

PURPOSE: The purpose of the Danish HIV Birth Cohort (DHBC) is to investigate the significance of HIV-1 infection in pregnancy and after delivery in women living with HIV (WLWH) in Denmark and their children, in the era of antiretroviral therapy and other interventions for treatment and prophylaxis. PARTICIPANTS: All WLWH giving birth to one or more children in Denmark after 31 December 1999 are included, with consecutive ongoing enrolment, if they are living with HIV and pregnant, or if they are diagnosed with HIV in relation to pregnancy, delivery or shortly after delivery. FINDINGS TO DATE: DHBC has been used to describe trends in the management of pregnancies in WLWH and their outcomes on a nationwide basis, mode of delivery and predictors of emergency caesarean section as well as risk factors during pregnancy in WLWH for birth-related complications compared with women from the general population (WGP). We have found that HIV-exposed, but uninfected (HEU) children born to WLWH had a lower median birth weight and gestational age and were at higher risk of intrauterine growth retardation than children born to WGP. We have investigated risk of in-hospital admission and use of antibiotics during the first 4 years of life among HEU children and showed that HEU children had an increased risk of overall hospital admission compared with a matched control group of unexposed children. Further, we compared anthropometric outcomes in children with a matched control group of children not exposed to HIV. FUTURE PLANS: To continuously investigate the significance of HIV infection and antiretroviral therapy in pregnancy and after delivery in WLWH in Denmark and their HEU children and compare these findings with children born to WGP

Vaginal Microbicide Preferences Among Midwestern Urban Adolescent Women

Purpose The purpose of this study was to assess adolescent women's preferences for specific microbicide characteristics including pregnancy prevention, timing of application, potential for side effects, and whether it targeted human immunodeficiency virus (HIV) or other sexually transmitted infections (STI). Potential differences in microbicide preferences by adolescent age group and behavioral patterns including engaging in sexual intercourse and use of hormonal contraception were examined, as it was hypothesized that as adolescents progress into adulthood and gain sexual experience their preferences in microbicide characteristics may shift. Method Adolescent and young women (N = 405, 56.0% African American; 24.0% Euro-American) between the ages of 14 and 20 (mean = 17.0, SD = 1.8) were recruited from urban community-based clinics. Video-Audio Computer-Assisted Self-Interviews were conducted with the young women, during which they were asked about their preferences regarding the characteristics of hypothetical vaginal microbicides. Conjoint analysis was utilized to determine adolescent women's relative preferences for each microbicide characteristic and intent-to-purchase microbicides based upon a combination of the selected properties. Results Overall, the results suggest adolescent and young women had an ordered preference for a microbicide with (1) no side effects, (2) pregnancy prevention, (3) postcoital application, and (4) protection against HIV. Age and behavioral group conjoint analyses resulted in the same pattern of preferences as those reported for the entire group. However, women having sex and not using hormonal contraception had a stronger preference for postcoital application. Conclusion The findings suggest that young women's ratings of microbicides were sensitive to characteristics such as side effects, pregnancy prevention, and timing of application and should be considered in microbicide development. The conjoint analysis approach is useful in understanding microbicide preferences, and should be utilized with other populations to assess preferences for specific microbicide characteristics