The Effects of Chemical and Mechanical Control of Woody Plants on Resprouting and Seedling Production in Communal Rangelands

In many African countries, communal rangelands are threatened by woody plant encroachment. We sought to explore potential solutions for communal ranchers that would be cost-effective. We conducted two field experiments to determine (1) the effects of various tree removal treatments (10%, 20%, 50%, 75% and 100%), and herbicide application on resprouting ability and vigour of several woody plant species; and (2) the effectiveness of Tree Poppers® (a weed wrench) as a low-cost mechanical control tool to physically uproot seedlings and saplings of woody species. In the first experiment, we examined 12 plant species from 20 plots (30 m x 30 m) each subjected to tree removal, followed by herbicide application on half of the stumps for each plot. In the second experiment, eight dominant tree species were grouped into three height classes (0-49 cm, 50-99 cm, 100-150 cm) of ten seedlings and saplings per species per height class. All the tree species in this study resprouted six months after cutting. Herbicide application significantly reduced the resprouting ability of Dichrostachys cinerea (L.) Wight & Arn, Ehretia rigida (Thunb.) Druce, Vachellia robusta (Burch.) Kyalangalilwa & Boatwright and Ziziphus mucronata Willd. Tree removal positively influenced the resprouting ability and vigour of only Euclea crispa (Thunb.) Gürke. The diameter of stumps was an important factor in determining resprouting ability, with shoot production decreasing with increasing stump diameter. We found no significant differences in the number of seedlings and saplings uprooted by Tree Poppers® among the different size classes. There were significant differences in the number of juveniles uprooted using a weed wrench with only a few individuals of Vachellia species uprooted. Woody plants are more likely to resprout and survive as juveniles than as adults after cutting. Communal ranchers may mechanically control shallow-rooted tree seedlings with a weed wrench but not deep-rooted ones, such as Vachellia species

Social representations and the politics of participation

Recent work has called for the integration of different perspectives into the field of political psychology (Haste, 2012). This chapter suggests that one possible direction that such efforts can take is studying the role that social representations theory (SRT) can play in understanding political participation and social change. Social representations are systems of common-sense knowledge and social practice; they provide the lens through which to view and create social and political realities, mediate people's relations with these sociopolitical worlds and defend cultural and political identities. Social representations are therefore key for conceptualising participation as the activity that locates individuals and social groups in their sociopolitical world. Political participation is generally seen as conditional to membership of sociopolitical groups and therefore is often linked to citizenship. To be a citizen of a society or a member of any social group one has to participate as such. Often political participation is defined as the ability to communicate one's views to the political elite or to the political establishment (Uhlaner, 2001), or simply explicit involvement in politics and electoral processes (Milbrath, 1965). However, following scholars on ideology (Eagleton, 1991; Thompson, 1990) and social knowledge (Jovchelovitch, 2007), we extend our understanding of political participation to all social relations and also develop a more agentic model where individuals and groups construct, develop and resist their own views, ideas and beliefs. We thus adopt a broader approach to participation in comparison to other political-psychological approaches, such as personality approaches (e.g. Mondak and Halperin, 2008) and cognitive approaches or, more recently, neuropsychological approaches (Hatemi and McDermott, 2012). We move away from a focus on the individual's political behaviour and its antecedents and outline an approach that focuses on the interaction between psychological and political phenomena (Deutsch and Kinnvall, 2002) through examining the politics of social knowledge

Broadly neutralizing antibody specificities detected in the genital tract of HIV-1 infected women.

CAPRISA, 2016.Abstract available in PDF file.

Structure of an N276-dependent HIV-1 neutralizing antibody targeting a rare V5 glycan hole adjacent to the CD4 binding site.

CAPRISA, 2016.Abstract available in pdf

Obligation to family during times of transition: care, support and the response to HIV and AIDS in rural South Africa

In rural South Africa, high HIV prevalence has the potential to affect the care and support that kin are able to provide to those living with HIV. Despite this, families seem to be largely resilient and a key source of care and support to family affected by HIV. In this article, we explore the motivations for the provision of care and support by kin. We use the results of a small-scale in-depth qualitative study conducted in 10 households over 6 months in rural KwaZulu-Natal, South Africa, to show that family obligation and conditional reciprocity operate in varying degrees and build social capital. We highlight the complexity of kin relations where obligation is not guaranteed or is limited, requiring the consideration of policy measures that provide means of social support that are not reliant on the family

The influence of different helminth infection phenotypes on immune responses against HIV in co-infected adults in South Africa

<p>Abstract</p> <p>Background</p> <p>The convergent distribution of the Human Immunodeficiency Virus (HIV) and helminth infections has led to the suggestion that infection with helminths exacerbates the HIV epidemic in developing countries. In South Africa, it is estimated that 57% of the population lives in poverty and carries the highest burden of both HIV and helmith infections, however, the disease interactions are under-researched.</p> <p>Methods</p> <p>We employed both coproscopy and <it>Ascaris lumbricoides</it>-specific serum IgE to increase diagnostic sensitivity and to distinguish between different helminth infection phenotypes and their effects on immune responses in HIV co-infected individuals. Coproscopy was done by formol ether and Kato Katz methods. HIV positive and negative adults were stratified according to the presence or absence of <it>A. lumbricoides </it>and/or <it>Trichuris trichuria </it>eggs with or without elevated <it>Ascaris </it>IgE. Lymphocyte subsets were phenotyped by flow cytometry. Viral loads, serum total IgE and eosinophils were also analysed. Lymphocyte activation markers (CCR5, HLA-DR, CD25, CD38 and CD71) were determined. Non parametric statistics were used to describe differences in the variables between the subgroups.</p> <p>Results</p> <p>Helminth prevalence ranged between 40%-60%. Four distinct subgroups of were identified, and this included egg positive/high <it>Ascaris</it>-specific IgE (egg⁺IgE^hi), egg positive/low IgE (egg⁺IgE^lo), egg negative/high IgE (egg^-IgE^hi) and egg negative/low IgE (egg^-IgE^lo) individuals. The egg⁺IgE^hisubgroup displayed lymphocytopenia, eosinophilia, (low CD4⁺counts in HIV^-group), high viral load (in HIV⁺group), and an activated lymphocyte profile. High <it>Ascaris </it>IgE subgroups (egg⁺IgE^hiand egg^-IgE^hi) had eosinophilia, highest viral loads, and lower CD4⁺counts in the HIV^-group). Egg excretion and low IgE (egg⁺IgE^lo) status demonstrated a modified Th₂immune profile with a relatively competent response to HIV.</p> <p>Conclusions</p> <p>People with both helminth egg excretion and high <it>Ascaris</it>-IgE levels had dysregulated immune cells, high viral loads with more immune activation. A modified Th₂helminth response in individuals with egg positive stools and low <it>Ascaris </it>IgE showed a better HIV related immune profile. Future research on helminth-HIV co-infection should include parasite-specific IgE measurements in addition to coproscopy to delineate the different response phenotypes. Helminth infection affects the immune response to HIV in some individuals with high IgE and egg excretion in stool.</p

Philosophical racism and ubuntu: In dialogue with Mogobe Ramose

This article discusses two complementary themes that play an important role in contemporary South African political philosophy: (1) the racist tradition in Western philosophy; and (2) the role of ubuntu in regaining an authentic African identity, which was systematically suppressed during the colonial past and apartheid. These are also leading themes in Mogobe Ramose’s African Philosophy Through Ubuntu. The first part concentrates on John Locke. It discusses the thesis that the reprehensible racism of many founders of liberal political philosophy has lethally infected liberal theory

Home language, school language and children's literacy attainments: A systematic review of evidence from low‐ and middle‐income countries

The general consensus in the field is that when the home language is different from the language of instruction in school then children's literacy attainments could slow down. In this 26-year review of the literature on children's literacy attainments in low- to middle-income countries, 40 correlational, ethnographic and intervention studies provide the data. We test the ‘home language advantage’ hypothesis where we expect children who speak the same language at home and school to show better literacy learning. We also examine other attributes in the home language and literacy environment (HLLE). Among the multivariate studies, trends differ across countries, age and grade levels, and child measures. Rather than a universal home language advantage, the evidence shows that home language advantage is context-sensitive. The correlational and ethnographic evidence point to a multiple risk factors model of home and school language disconnection; and the ethnographic and intervention studies provide complementary evidence of both feelings of unease, disempowerment and wish to help among family members, and increased confidence following guided support. Possible underlying mechanisms are examined through parallel synthesis of evidence from multiple research methods on three HLLE dimensions—books-at-home, home tutoring and adult literacy practices. The data partially corroborate findings from high-income countries (e.g. home environments impact literacy development, responsive parenting is present across families) but also bring focus on context-specific realities. Neither low-income nor low-print environments are uniform constraints because communities differ and some homes use available resources more efficiently than others