RESUMEN

A synthesis route for the preparation of optically transparent magnesium fluoride sols using magnesium acetate tetrahydrate as precursor is described. The obtained magnesium fluoride sols are stable for several months and can be applied for antireflective coatings on glass substrates. Reaction parameters in the course of sol synthesis are described in detail. Thus, properties of the precursor materials play a crucial role in the formation of the desired magnesium fluoride nanoparticles, this is drying the precursor has to be performed under defined mild conditions, re-solvation of the dried precursor has to be avoided and addition of water to the final sol-system has to be controlled strictly. Important properties of the magnesium fluoride sols like viscosity, particle size distribution, and structural information are presented as well.

RESUMEN

The hydroxyl radical (OH) is a key oxidant involved in the removal of air pollutants and greenhouse gases from the atmosphere. The ratio of Northern Hemispheric to Southern Hemispheric (NH/SH) OH concentration is important for our understanding of emission estimates of atmospheric species such as nitrogen oxides and methane. It remains poorly constrained, however, with a range of estimates from 0.85 to 1.4 (refs 4, 7-10). Here we determine the NH/SH ratio of OH with the help of methyl chloroform data (a proxy for OH concentrations) and an atmospheric transport model that accurately describes interhemispheric transport and modelled emissions. We find that for the years 2004-2011 the model predicts an annual mean NH-SH gradient of methyl chloroform that is a tight linear function of the modelled NH/SH ratio in annual mean OH. We estimate a NH/SH OH ratio of 0.97 ± 0.12 during this time period by optimizing global total emissions and mean OH abundance to fit methyl chloroform data from two surface-measurement networks and aircraft campaigns. Our findings suggest that top-down emission estimates of reactive species such as nitrogen oxides in key emitting countries in the NH that are based on a NH/SH OH ratio larger than 1 may be overestimated.

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RESUMEN

PIP: The conditions of Burmese prostitutes in Thailand's border communities are described to show how they are mistreated and denied health information on AIDS prevention. The police had been returning prostitutes to Myanmar, until it was brought to their attention that 25 female prostitutes had been fatally injected with cyanide by Burmese authorities to stop the spread of HIV. Myanmar's military rulers have concentrated AIDS education on the military. They do not want the soldiers, who keep the military regime in power to become infected with AIDS. The reports of Burmese murders of prostitutes have come from all quarters. In the group of 25 prostitutes were two cousins of a Burmese citizen who reported the disappearance of his relatives after they left for a shopping trip in the southern Thai city of Ranong, opposite Kawthaung in Myanmar. Thai police found that the two cousins had been kidnapped and sold into prostitution in a brothel in Ranong, which had been raided by police. In the northern city of Chiang Mai, it is estimated that 10,000 of the prostitutes are Burmese girls and women. UNICEF has reported that as many as 40,000 Burmese girls are sold into prostitution in Bangkok and border towns such as Ranong and Chiang Mai. Anti-Slavery International estimated that more than 1500 of the prostitutes in Ranong are Burmese girls and women who have been forced into this work. Their condition is very similar to slavery. Girls are forced to work long hours and may be fed only a bowl of rice with watery soup. Prostitution flourished because 20,000 Burmese fisherman, who are at sea for prolonged periods, frequent the brothels on their return. There is a growing prevalence of HIV infection in Ranong in part due to the fishermen's widespread heroin use aboard ship. In Ranong, 1 in 5 prostitutes were found to be HIV positive including 1 in 3 of the Burmese women. Those locked in brothels are not included in the figures. Unfortunately the Burmese captives know no or very little Thai or English, which means there is no exposure to AIDS prevention efforts. Conditions were reported in a letter signed by 73 Burmese captive prostitutes who wanted to return to their parents. The letter was smuggled out of brothel operating in the Grand Victoria Hotel in Ranong. POlice raids and the return of prostitute to Myanmar by boat have been hindered by brothel owners who bribe officials.^ieng

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