There is widespread concern that the number of children living in "child-headed households" is rapidly increasing as a result of AIDS-related adult mortality in much of sub-Saharan Africa. Based on analyses of data from several representative national surveys over the period 2000-2007, this paper examines the extent to which this is the case in South Africa. It explores trends in the number of ...

Mammalian oocytes grow within ovarian follicles in which the oocyte is coupled to surrounding granulosa cells by gap junctions. We report here that growing oocytes isolated from mouse preantral follicles are incapable of recovering from an experimentally induced acidosis, and that oocytes acquire the ability to manage acid loads by activating Na(+)/H(+) exchange during growth. By contrast, gran...

Background: The United Nations has predicted that the population of slum dwellers will have grown from one billion people worldwide to 2 billion by 2030. This trend is also predictable in Iran. In the Iranian metropolis of Shiraz, more than 10% of the residents live in slum areas. There are several problems regarding the delivery of social services in these areas. The aim of this study was to e...

Background Very few studies have assessed performance of Botswana public hospitals. We draw from a large research study assessing performance of the Botswana Ministry of Health (MoH) to evaluate the performance of public hospital system using the World Health Organization Health Systems Performance Assessment Framework (WHO HSPAF). We aimed to evaluate performance of Botswana public hospital sy...

Scientists in many disciplines have progressively been using simulations to better understand the natural systems they study. Faster hardware, as well as increasingly precise instruments, allow the construction and simulation of progressively advanced models of various systems. Governed by algorithms and equations, the spatial models at the core of simulations are changed and updated at every s...

The Web is playing a very important role in our lives, and is becoming an essential element of the computing infrastructure. With such a glory come the attacks–the Web has become criminals’ preferred targets. Web-based vulnerabilities now outnumber traditional computer security concerns. Although various security solutions have been proposed to address the problems on the Web, few have addresse...

We propose a method that finds the position and orientation of an acoustic source in an enclosed environment. For each of eight T-shaped arrays forming a microphone array network, the time delay of arrival (TDOA) of signals from microphone pairs, a source position candidate, and energy related features are estimated. These form the input for artificial neural networks (ANNs), the purpose of whi...