Chronic venous disorders

Chronic venous disorders encompass a spectrum of venous diseases, ranging from simple telangiectases (spider veins), reticular veins, varicose veins, and leg oedema to more severe advanced forms of disorders, including hyperpigmented skin changes, dermal sclerosis, and ulcer formation. Part of the spectrum of chronic venous disorders includes varicose veins, oedema, skin changes and ulcers affecting the lower limb, which are categorised as chronic venous disease (CVD). Chronic venous disorders with manifestations specific to abnormal venous function are grouped under the term chronic venous insufficiency (CVI). A distinguishing feature between CVD and CVI is that the latter indicates more advanced forms of chronic venous disorders. Accordingly, CVI includes manifestations such as skin pigmentation, venous eczema, lipodermatosclerosis, atrophie blanche, and healed or active ulcers

Women and transformation: A recurrent theme in Head and Ngugi

This article evaluates, within the context of the increasingly important position assigned to African literature in general (and the novel in particular), the dominant roles played by Bessie Head and Ngugi through a focus on the significant contributions of these two writers concerning the theme of women and transformation. Although both authors put a high premium on wotnanism, showing themselves as champions of especially sexual and racial freedom for all women, their novels indicate different trends in their portrayal of this theme. Head, for instance, becomes increasingly autobiographical in her articulation of her female protagonists ’ struggle for freedom from oppression, while Ngugi tends to become increasingly politically biased in expressing his Marxist social, political and economic doctrines. This article furthermore examines the ways in which Ngugi and Head highlight different aspects of the discourse of female liberation, while also studying the dialogue of transformation and a sense of belonging. Finally, it remarks on Head's and Ngugi's aesthetic approaches to the discourse of women and transformation

The occurrence and removal of algae (including cyanobacteria) and their related organic compounds from source water in Vaalkop Dam with conventional and advanced drinking water treatment processes

Cyanobacterial bloom formation in freshwaters, such as rivers, lakes and dams, is known to occur throughout the world. The Vaalkop Dam, which serves as source to the Vaalkop drinking water treatment works (DWTW), is no exception. Blooms of cyanobacteria occur annually in Vaalkop Dam as well as in dams from which Vaalkop is replenished during low-rainfall periods. These blooms during the summer months are associated with the production of cyanotoxins and taste and odour compounds such as geosmin and MIB. The Vaalkop DWTW uses a combination of conventional and advanced water treatment processes to deal with the cyanobacteria and their related organic compounds in the source water. The overall objectives of this study were to: (i) investigate the occurrence of algae (including cyanobacteria) and cyanotoxins in the Vaalkop Dam; (ii) establish which environmental variables are responsible for the development and onset of algae, and (iii) determine whether the Vaalkop DWTW is able to eliminate the influence that algae (including cyanobacteria) may have on the drinking water. Multivariate statistical analyses revealed seasonal variation in algal assemblages in the raw water. The risk of cyanobacteria bloom formation proved to be especially high during the summer months as the nutrients needed for cyanobacterial growth are available and the temperature range is optimal, causing the production of geosmin, MIB and microcystin. The presence of Ceratium hirundinella (O.F. Müller) Dujardin, in the source water appears to exacerbate the negative effect that cyanobacteria have on the drinking water treatment process. When Ceratium hirundinella is present, floc formation is inhibited, causing more of the problematic algae to penetrate into the drinking water. Even though advanced treatment options such as ozone and granular activated carbon filters are used at Vaalkop DWTW, the effects of the organic compounds produced by cyanobacteria are not entirely eliminated during the treatment process.Keywords: potable water treatment, geosmin, MIB (2-methylisoborneol), microcystin, granular activated carbon (GAC), ozon

Integration of chemical looping combustion for cost-effective CO2 capture from state-of-the-art natural gas combined cycles

Chemical looping combustion (CLC) is a promising method for power production with integrated CO2 capture with almost no direct energy penalty. When integrated into a natural gas combined cycle (NGCC) plant, however, CLC imposes a large indirect energy penalty because the maximum achievable reactor temperature is far below the firing temperature of state-of-the-art gas turbines. This study presents a techno-economic assessment of a CLC plant that circumvents this limitation via an added combustor after the CLC reactors. Without the added combustor, the energy penalty amounts to 11.4%-points, causing a high CO2 avoidance cost of $117.3/ton, which is more expensive than a conventional NGCC plant with post-combustion capture ($93.8/ton) with an energy penalty of 8.1%-points. This conventional CLC plant would also require a custom gas turbine. With an added combustor fired by natural gas, a standard gas turbine can be deployed, and CO2 avoidance costs are reduced to $60.3/ton, mainly due to a reduction in the energy penalty to only 1.4$96.3/ton when a hydrogen cost of $15.5/GJ is assumed. Advanced heat integration could reduce the CO2 avoidance cost to$90.3/ton by lowering the energy penalty to only 0.6%-points. An attractive alternative is, therefore, to construct the plant for added firing with natural gas and retrofit the added combustor for hydrogen firing when CO2 prices reach very high levels

Social constructions of gender roles, gender-based violence and HIV/AIDS in two communities of the Western Cape, South Africa

The links between gender roles, gender-based violence and HIV/AIDS risk are complex and culturally specific. In this qualitative study we investigated how women and men in two black communities in the Western Cape, South Africa, constructed their gender identities and roles, how they understood gender-based violence, and what they believed about the links between gender relations and HIV risk. First we conducted 16 key informant interviews with members of relevant stakeholder organisations. Then we held eight focus group discussions with community members in single-sex groups. Key findings included the perception that although traditional gender roles were still very much in evidence, shifts in power between men and women were occurring. Also, gender-based violence was regarded as a major problem throughout communities, and was seen to be fuelled by unemployment, poverty and alcohol abuse. HIV/AIDS was regarded as particularly a problem of African communities, with strong themes of stigma, discrimination, and especially ‘othering' evident. Developing effective HIV/AIDS interventions in these communities will require tackling the overlapping as well as divergent constructions of gender, gender violence and HIV which emerged in the study. Keywords: gender roles, gender-based violence, HIV/AIDS, South Africa. RÉSUMÉ Les liens entre les rôles de genre, la violence contre les femmes et le risque du VIH/SIDA sont complexes et culturellement particuliers. Dans cette étude qualitative, nous avons examiné: comment des hommes et des femmes ont construit des identités et les rôles de genre dans deux communautés noires du Cap de l'Ouest, en Afrique du Sud, comment ont-ils compris la violence contre les femmes et ce qu'ils croyaient des liens entre les relations de sexes et le risque du VIH. Dans un premier temps, nous avons mené 16 entretiens principaux d'informateurs auprès des membres des organismes dépositaires. Ensuite, nous avons eu huit discussions des groupes de foyer avec des membres de la communauté en deux groupes différents, un pour les femmes un autre pour les hommes. Les résultats de recherche ont inclus la perception que: même si les rôles de genre traditionnels restent toujours évidents, il y a aussi le déplacement de pouvoir entre les hommes et les femmes. De plus, la violence contre les femmes était vue comme un problème majeur à travers les communautés et d'être aggravée par le chômage, la pauvreté et l'abus d'alcool. Le VIH/SIDA était considéré particulièrement comme un problème des communautés africaines avec des thèmes fortes de stigmatisation, de discrimination et surtout le ‘othering' évidents. Le développement des interventions efficaces du VIH/SIDA dans ces communautés va exiger une maîtrise des constructions de genre qui se recouvrent partiellement et qui sont divergentes également, la violence contre les femmes et le VIH qui ont apparu dans cette étude. Mot clés: les rôles de genre, la violence contre les femmes, le VIH/SIDA, l'Afrique du Sud

An integrated approach to pathogen transmission via environmental reservoirs

To mitigate the effects of zoonotic diseases on human and animal populations, it is critical to understand what factors alter transmission dynamics. Here we assess the risk of exposure to lethal concentrations of the anthrax bacterium, Bacillus anthracis, for grazing animals in a natural system over time through different transmission mechanisms. We follow pathogen concentrations at anthrax carcass sites and waterholes for five years and estimate infection risk as a function of grass, soil or water intake, age of carcass sites, and the exposure required for a lethal infection. Grazing, not drinking, seems the dominant transmission route, and transmission is more probable from grazing at carcass sites 1–2 years of age. Unlike most studies of virulent pathogens that are conducted under controlled conditions for extrapolation to real situations, we evaluate exposure risk under field conditions to estimate the probability of a lethal dose, showing that not all reservoirs with detectable pathogens are significant transmission pathways

Systems Approach to Human Hair Fibers: Interdependence Between Physical, Mechanical, Biochemical and Geometric Properties of Natural Healthy Hair

Contextual interpretation of hair fiber data is often blind to the effects of the dynamic complexity between different fiber properties. This intrinsic complexity requires systems thinking to decipher hair fiber accurately. Hair research, studied by various disciplines, follows a reductionist research approach, where elements of interest are studied from a local context with a certain amount of detachment from other elements or contexts. Following a systems approach, the authors are currently developing a cross-disciplinary taxonomy to provide a holistic view of fiber constituents and their interactions within large-scale dynamics. Based on the development process, this paper presents a review that explores the associated features, interrelationships and interactive complexities between physical, mechanical, biochemical and geometric features of natural, healthy hair fibers. Through the review, the importance of an appropriate taxonomy for interpreting hair fiber data across different disciplines is revealed. The review also demonstrates how seemingly unrelated fiber constituents are indeed interdependent and that these interdependencies may affect the behavior of the fiber. Finally, the review highlights how a non-integrative approach may have a negative impact on the reliability of hair data interpretation

Stigma and discrimination experiences of HIV-positive men who have sex with men in Cape Town, South Africa

Since the primary mode of HIV transmission in sub-Saharan Africa is heterosexual, research focusing on the sexual behaviour of men who have sex with men (MSM) is scant. Currently it is unknown how many people living with HIV in South Africa are MSM and there is even less known about the stigmatisation and discrimination of HIV-positive MSM. The current study examined the stigma and discrimination experiences of MSM living with HIV/AIDS in South Africa. Anonymous venue-based surveys were collected from 92 HIV-positive MSM and 330 HIV-positive men who only reported sex with women (MSW). Internalised stigma was high among all HIV-positive men who took part in the survey, with 56% of men reporting that they concealed their HIV status from others. HIV-positive MSM reported experiencing greater social isolation and discrimination resulting from being HIV-positive, including loss of housing or employment due to their HIV status, however these differences were not significant. Mental health interventions, as well as structural changes for protection against discrimination, are needed for HIV-positive South African MSM

From exclusion to informal segregation: The limits to racial transformation at the University of Natal

In the context of higher education transformation in South Africa, this paper attempts to capture a series of observations about transformation at the forme r University ofNatal. From a descriptive, multidisciplinary perspective it critiques racial transformation at the University as driven by concerns of representivity over the need for desegregation. We base this discussion on three sets of observations: an analysis of institutional policy, a review of demographic change in the staff and student bodies and a study ofstudents ' lived experiences of segregation on campus. During the past decade a great deal ofchange has occurred in the overall racial demographics of the student and staff bodies. While demographic transformation efforts at the University do echo national trends, a closer inspection ofthe policy, practice and lived experience oftransformation at the University reveals that all is not well. In particular, institutional policy with respect to transformation has tended to be reactive and superficial and students experience camp us as a segregated and racialized space. Thus, racial transformation at the University has only been partially successful: while overt racist exclusion is withering, informal segregation and attendant racialization remain

Quantifying water requirements of African ungulates through a combination of functional traits

Climate and land use change modify surface water availability in African savannas. Surface water is a key resource for both wildlife and livestock and its spatial and temporal distribution is important for understanding the composition of large herbivore assemblages in savannas. Yet, the extent to which ungulate species differ in their water requirements remains poorly quantified. Here, we infer the water requirements of 48 African ungulates by combining six different functional traits related to physiological adaptations to reduce water loss, namely minimum dung moisture, relative dung pellet size, relative surface area of the distal colon, urine osmolality, relative medullary thickness, and evaporation rate. In addition, we investigated how these differences in water requirements relate to differences in dietary water intake. We observed strong correlations between traits related to water loss through dung, urine and evaporation, suggesting that ungulates minimize water loss through multiple pathways simultaneously, which suggests that each trait can thus be used independently to predict water requirements. Furthermore, we found that browsers and grazers had similar water requirements, but browsers are expected to be less dependent on surface water because they acquire more water through their diet. We conclude that these key functional traits are a useful way to determine differences in water requirements and an important tool for predicting changes in herbivore community assembly resulting from changes in surface water availability