The impact and cost of the HIV/AIDS investment framework for adolescents.

BACKGROUND: In 2005, the resources needed to support orphans and vulnerable children in sub-Saharan Africa were estimated at US$ 1.1-4.1 billion. Approaches to support vulnerable children have changed considerably since then. This study updates previous estimates by including new types of support and information on support costs. METHODS: We considered 16 types of support categorized as economic strengthening, education support, social care and community outreach, and program support. The estimates combine the number of children in need of each intervention with unit costs derived from the literature and coverage goals based on current coverage and feasible future improvements. RESULTS: The number of children affected by AIDS in low- and middle-income countries varies from 58 million to 315 million depending on the definition of need. The resources required to provide support to children living in poor households will grow from US$ 4.2 billion in 2012 to US$ 5-8 billion by 2020. Almost two-thirds of these resources will be needed for Sub-Saharan Africa. The largest needs are for cash transfers, community care workers, early childhood development, block grants for education, M&E monitoring and evaluation, and direct material support. DISCUSSION: The results show that we can significantly improve the coverage of services for vulnerable children with only modest increases in resources. This results from stable or declining numbers of orphans and children living with HIV plus economic growth that is moving more households out of poverty. The results also reflect an important shift toward providing support to strengthen families and communities that care for children rather than direct material support. CONCLUSION: More resources are required to support children affected by AIDS, but new approaches to provide that support will be cost effective and have broad social and economic benefits.

Determination of polar stratospheric cloud particle refractive indices by use of in situ optical measurements and T-matrix calculations.

A new algorithm to infer structural parameters such as refractive index and asphericity of cloud particles has been developed by use of in situ observations taken by a laser backscattersonde and an optical particle counter during balloon stratospheric flights. All three main particles, liquid, ice, and a no-ice solid (NAT, nitric acid trihydrate) of polar stratospheric clouds, were observed during two winter flights performed from Kiruna, Sweden. The technique is based on use of the T-matrix code developed for aspherical particles to calculate the backscattering coefficient and particle depolarizing properties on the basis of size distribution and concentration measurements. The results of the calculations are compared with observations to estimated refractive indices and particle asphericity. The method has also been used in cases when the liquid and solid phases coexist with comparable influence on the optical behavior of the cloud to estimate refractive indices. The main results prove that the index of refraction for NAT particles is in the range of 1.37-1.45 at 532 nm. Such particles would be slightly prolate spheroids. The calculated refractive indices for liquid and ice particles are 1.51-1.55 and 1.31-1.33, respectively. The results for solid particles confirm previous measurements taken in Antarctica during 1992 and obtained by a comparison of lidar and optical particle counter data.