Restructuring of Households in Rural South Africa: Reflections on Average Household Size in the Agincourt Sub-district 1992-2003

South Africa has seen a dramatic decrease in household size over the last decade. In Table 1 we show that over the eight-and-a-half years from October 1995 to March 2004 the average household size has decreased by 20% or 0.74 persons (see also Pirouz 2004). Consequently for a fixed population size there would have been 20% more households in March 2004 than in October 1995. Such a rapid rate of household formation is interesting in and of itself. From the perspective of a policy maker it is particularly vital to understand this process. The new democratic government has committed itself to extending infrastructure and social services to households in deprived communities and now finds that it is trying to catch a moving target. The backlogs are increasing as the services are being rolled out. We will suggest below that there might be a connection between these two processes.

The implications of long term community involvement for the production and circulation of population knowledge

Demographic surveillance systems (DSS) depend on community acceptance and involvement to produce high quality longitudinal data. Ensuring community support also exposes power relations usually concealed in the research process. We discuss the Agincourt Health and Demographic Surveillance System in South Africa to argue that: 1) long-term presence and community involvement contribute to high response rates and data quality, 2) to maintain community support the project must demonstrate its usefulness, 3) reporting to community members provides valuable checks on the local relevance and comprehension of questions, and 4) community opinion can modify both wording and content of research questions.community, demographic surveillance system, fertility, health, knowledge, longitudinal, migration, mortality, South Africa

On the characterisation of shock-induced sliding along multi-material interfaces

Experimental results utilising novel diagnostic techniques focussing on spatial resolution of shock-induced sliding phenomena at multi-material aluminium - stainless steel dry metallic contact interfaces are presented. Relative particle velocities of 50 m s⁻¹ are generated at the sliding interface via an intrinsic impedance mismatch between the material components, driven by gas gun flyer plate impact. Results are first presented for the metallography of recovered target samples from shock-induced sliding contact interfaces where the intrinsic grain structure is utilised as a fiducial marker to provide a measure of the sub-surface deformation experienced. Two distinct mutually exclusive scales of deformation were identified extending over millimetre and micrometre depths with relatively low and high free surface sliding velocities measured for these respectively using optical velocimetry. Further experimental results are presented for spatially resolved velocimetry of shock-induced sliding at planar material interfaces utilising a line-VISAR diagnostic. Experiments are conducted over 3 mm and 15 mm interface length scales with the contact interface orientated at 0.0° and 5.0° relative to the direction of loading. Specific material pairings of aluminium 1050 and aluminium 7068 paired independently with stainless steel 316 were utilised. An initial large scale experiment was found to be suggestive of the role of gaps at the contact interface, estimated to be 35 μm in size via comparison of the velocimetry data with hydrocode models. Further mesoscale experiments are suggestive of the role of re-shock and release waves generated at the contact face co-incident with the breakout of the elastic and plastic shock fronts, defining the velocimetry profile in close vicinity of the contact face over the timescales measured.Open Acces

Clustering South African households based on their asset status using latent variable models

The Agincourt Health and Demographic Surveillance System has since 2001 conducted a biannual household asset survey in order to quantify household socio-economic status (SES) in a rural population living in northeast South Africa. The survey contains binary, ordinal and nominal items. In the absence of income or expenditure data, the SES landscape in the study population is explored and described by clustering the households into homogeneous groups based on their asset status. A model-based approach to clustering the Agincourt households, based on latent variable models, is proposed. In the case of modeling binary or ordinal items, item response theory models are employed. For nominal survey items, a factor analysis model, similar in nature to a multinomial probit model, is used. Both model types have an underlying latent variable structure - this similarity is exploited and the models are combined to produce a hybrid model capable of handling mixed data types. Further, a mixture of the hybrid models is considered to provide clustering capabilities within the context of mixed binary, ordinal and nominal response data. The proposed model is termed a mixture of factor analyzers for mixed data (MFA-MD). The MFA-MD model is applied to the survey data to cluster the Agincourt households into homogeneous groups. The model is estimated within the Bayesian paradigm, using a Markov chain Monte Carlo algorithm. Intuitive groupings result, providing insight to the different socio-economic strata within the Agincourt region.Comment: Published in at http://dx.doi.org/10.1214/14-AOAS726 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

An investigation into the best interests of the child in decisions about the deportation of foreign national offenders in UK law

This thesis argues that UK deportation law exists in a state of tension. On the one hand, the political imperative to deport foreign national offenders, and on the other, to protect the human rights of children. The human rights of foreign national offender’s children, are protected in UK law by their right to family life (under Article 8 ECHR, domesticated by the Human Rights Act 1998), and their right to their best interests as a primary consideration, and not to be blamed for the wrongdoing of their parent (under Article 3 UNCRC, domesticated by s55 of the Borders, Citizenship and Immigration Act 2009). However, the right to family life under Article 8 ECHR may be interfered with on the basis of the public interest in deporting foreign national offenders. This tension in UK deportation law is evinced by the apparently irreconcilable characteristics of these legal obligations. This thesis theorises this by arguing that deportation decisions are polycentric in nature, because of the multiplicity of human rights and interests at stake and which must, by law, be given effect to. Furthermore, UK deportation law creates a plurality of decision-making norms; multiple legal principles which must also be given simultaneous effect to. This thesis traces the attempts of UK law to give effect to the best interests of the child in deportation decisions through three distinct phases of decision-making approach. It concludes that no deportation decision-making approach adopted to date has effectively reconciled the human rights obligations and the best interests of the child by resolving the problems of polycentricity and the plurality of decision-making norms. Finally, this thesis demonstrates that UK deportation law is capable of giving effect to the best interests of the child by taking the human rights of children both seriously and literally

Health impacts of social transistion: A study of female temporary migration and its impact on child mortality in rural South Africa

ABSTRACT: Temporary migration, especially men moving to their place of work, was an intrinsic feature of the former Apartheid system in South Africa. Since the demise of Apartheid an increasing proportion of women have also been migrating to their place of work, and oscillating between work place and home. Temporary migration can be defined as oscillating migration between a home base and at least one other place, usually for work, but also for other reasons like education. This study demonstrates that in the Agincourt study population, in the rural northeast of South Africa, adult female temporary migration is an increasing trend. By conducting a survival analysis, the study evaluates the mortality outcomes, specifically infant and child mortality rates, of children born to female temporary migrants compared with children of non-migrant women. Based on the findings presented we accept the null hypothesis that there is presently no discernable impact (positive or negative) of maternal temporary migration on infant and child mortality. There seems to be a slight protective factor associated with mother’s migration when tested at a univariate level. However, through multivariate analysis, it is shown that this advantage relates to the higher education status of migrating mothers. When women become tertiary educated there is a survival advantage to their children and these women are also more likely to migrate. The study highlights greater child mortality risks associated with settled Mozambicans (former refugees) and unmarried mothers. Both of these risk factors reflect the impact of high levels of social deprivation

The stall in fertility decline in rural, northeast, South Africa: the contribution of a self-settled, Mozambican, refugee sub-population

Using longitudinal data from the Agincourt Health and socio-Demographic Surveillance System (HDSS) in rural South Africa, this paper examines the role of the fertility of self-settled, former Mozambican refugee sub-population on the stall in fertility decline in the Agincourt HDSS from 1993 to 2009. The Agincourt HDSS fertility trend is decomposed to quantify the relative contribution of the Mozambicans to fertility changes. Results show that fertility level declined by about 1.5 children per woman over the period and the level remain around 2.5 children per woman in the last eight years of the period examined suggesting a stall in fertility decline in the sub-district population covered by the HDSS. However, while the fertility of the Mozambicans fell consistently over the period, there was a reversal in the fertility decline of South African women residing in the area suggesting that the overall stalls are attributable to stalls in fertility decline among South African women.

Refined measurement of SecA-driven protein secretion reveals that translocation is indirectly coupled to ATP turnover

The universally conserved Sec system is the primary method cells utilize to transport proteins across membranes. Until recently, measuring the activity—a prerequisite for understanding how biological systems work—has been limited to discontinuous protein transport assays with poor time resolution or reported by large, nonnatural tags that perturb the process. The development of an assay based on a split superbright luciferase (NanoLuc) changed this. Here, we exploit this technology to unpick the steps that constitute posttranslational protein transport in bacteria. Under the conditions deployed, the transport of a model preprotein substrate (proSpy) occurs at 200 amino acids (aa) per minute, with SecA able to dissociate and rebind during transport. Prior to that, there is no evidence for a distinct, rate-limiting initiation event. Kinetic modeling suggests that SecA-driven transport activity is best described by a series of large (∼30 aa) steps, each coupled to hundreds of ATP hydrolysis events. The features we describe are consistent with a nondeterministic motor mechanism, such as a Brownian ratchet