Physico-chemical and Mineralogical Characterisation of Subsurface Sediments around Gaborone Landfill, Botswana

Studies were carried out on subsurface sediments obtained around the Gaborone landfill area Botswana, in order to characterize their mineralogy and physico-chemistry, appraise any contaminant inputs from the landfill and assess their ability to attenuate contaminants from the landfill. Physico-chemical properties investigated included particle size distribution (PSD), moisture content, bulk density (Db), porosity, surface area, pH, electrical conductivity (EC), and cation exchange capacity (CEC). The mineral phases occurring in the subsurface sediments were identified by use of X-ray powder diffraction (XRPD) technique. Grain size analyses of the subsurface sediments revealed sandy loam, silty loam, and silt as the main textural classes. The values obtained for Db and porosity is reflective of the textural classes of the different samples. Moisture content values of the studied samples are characteristic of sediments in semi-arid environments. Apart from two samples, which were acidic, others were alkaline. The EC values were indicative of significant amounts of total dissolved salts (TDS) especially along the eastern corner of the landfill. Cation exchange capacity values were relatively low. Minerals identified by XRPD included quartz, microcline, muscovite and kaolinite in bulk subsurface sediments, whereas kaolinite, smectite and /or illite occurred in the clay fractions. Sediment pH, EC and TDS suggests inputs from the landfill. The sediments seem to have a low attenuation capacity as a result of their physico-chemical and mineralogical properties. Further geophysical and hydrogeochemical research is needed to verify if the Gaborone landfill area is environmentally safe. @JASE

Chimpanzee reservoirs of pandemic and nonpandemic HIV-1

Human immunodeficiency virus type 1 (HIV-1), the cause of human acquired immunodeficiency syndrome ( AIDS), is a zoonotic infection of staggering proportions and social impact. Yet uncertainty persists regarding its natural reservoir. The virus most closely related to HIV-1 is a simian immunodeficiency virus ( SIV) thus far identified only in captive members of the chimpanzee subspecies Pan troglodytes troglodytes. Here we report the detection of SIVcpz antibodies and nucleic acids in fecal samples from wild-living P.t. troglodytes apes in southern Cameroon, where prevalence rates in some communities reached 29 to 35%. By sequence analysis of endemic SIVcpz strains, we could trace the origins of pandemic ( group M) and nonpandemic ( group N) HIV-1 to distinct, geographically isolated chimpanzee communities. These findings establish P. t. troglodytes as a natural reservoir of HIV-1

Proceedings of the second "international Traveling Workshop on Interactions between Sparse models and Technology" (iTWIST'14)

The implicit objective of the biennial "international - Traveling Workshop on Interactions between Sparse models and Technology" (iTWIST) is to foster collaboration between international scientific teams by disseminating ideas through both specific oral/poster presentations and free discussions. For its second edition, the iTWIST workshop took place in the medieval and picturesque town of Namur in Belgium, from Wednesday August 27th till Friday August 29th, 2014. The workshop was conveniently located in "The Arsenal" building within walking distance of both hotels and town center. iTWIST'14 has gathered about 70 international participants and has featured 9 invited talks, 10 oral presentations, and 14 posters on the following themes, all related to the theory, application and generalization of the "sparsity paradigm": Sparsity-driven data sensing and processing; Union of low dimensional subspaces; Beyond linear and convex inverse problem; Matrix/manifold/graph sensing/processing; Blind inverse problems and dictionary learning; Sparsity and computational neuroscience; Information theory, geometry and randomness; Complexity/accuracy tradeoffs in numerical methods; Sparsity? What's next?; Sparse machine learning and inference.Comment: 69 pages, 24 extended abstracts, iTWIST'14 website: http://sites.google.com/site/itwist1

Track E Implementation Science, Health Systems and Economics

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138412/1/jia218443.pd

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Indigenous Knowledge Applied to the Use of Clays for Cosmetic Purposes in Africa: An Overview

The use of clay for cosmetic purposes in Africa is an age-old long-standing practice, which has been practiced through all regions of the continent. Red, white, yellow and their related shades of clays, in combination with other natural substances such as plant and animal extracts have over time been used by different indigenous African communities to meet their cosmetic needs. The purposes advanced for the cosmetic usage of these clays include cleansing the skin, protecting the skin against ultraviolet radiation, skin lightening, hiding of skin imperfections and accentuating the beauty of specific parts of the body. This paper provides an overview of the traditional usage of clays for cosmetic purposes in indigenous African communities. It identifies the types of cosmetic clays used traditionally in different African communities and the current reasons advanced for their application. It also sheds light on the historical use of cosmetic clays; thus emphasizing that knowledge about their applications is not new to the African community. Over time clays have been used to meet aesthetic demands including dermatological beautification.Keywords: Clay, cosmetics, indigenous knowledge, beauty, Africa

Physico-chemical and Mineralogical Characterisation of Subsurface Sediments around Gaborone Landfill, Botswana

Studies were carried out on subsurface sediments obtained around the Gaborone landfill area Botswana, in order to characterize their mineralogy and physico-chemistry, appraise any contaminant inputs from the landfill and assess their ability to attenuate contaminants from the landfill. Physico-chemical properties investigated included particle size distribution (PSD), moisture content, bulk density (Db), porosity, surface area, pH, electrical conductivity (EC), and cation exchange capacity (CEC). The mineral phases occurring in the subsurface sediments were identified by use of X-ray powder diffraction (XRPD) technique. Grain size analyses of the subsurface sediments revealed sandy loam, silty loam, and silt as the main textural classes. The values obtained for Db and porosity is reflective of the textural classes of the different samples. Moisture content values of the studied samples are characteristic of sediments in semi-arid environments. Apart from two samples, which were acidic, others were alkaline. The EC values were indicative of significant amounts of total dissolved salts (TDS) especially along the eastern corner of the landfill. Cation exchange capacity values were relatively low. Minerals identified by XRPD included quartz, microcline, muscovite and kaolinite in bulk subsurface sediments, whereas kaolinite, smectite and /or illite occurred in the clay fractions. Sediment pH, EC and TDS suggests inputs from the landfill. The sediments seem to have a low attenuation capacity as a result of their physico-chemical and mineralogical properties. Further geophysical and hydrogeochemical research is needed to verify if the Gaborone landfill area is environmentally safe. Journal of Applied Sciences and Environmental Management Vol. 8 (1) 2004: 49 - 5

Ceremonial Usage of Clays for Body Painting According to Traditional Xhosa Culture

Cultural practices are explored and expressed in daily living through the creative abilities of every person. This article presents an analytical critique of the uses of clays for body painting and its ceremonial and ritual significance. It reports on an ethnographic study conducted to distinguish between various functions and reasons for the practice. The study is informed by cultural knowledge from rural communities within OR Tambo District in Eastern Cape Province of South Africa. Samples of clays used for ceremonial and ritual body paintings were analysed to determine their physico-chemical and mineralogical properties. The main objective was to investigate whether there is merit in this traditional practice. Using standard laboratory techniques, physico-chemical properties such as colour, particle size distribution, pH and cation exchange capacity of the samples were determined. Minerals identification was conducted using X-Ray Diffractometry. It was identified that the clay colours varied from white to yellow and red; and pH values ranged from 4.53 to 9.57. Whereas all the samples contained fractions of clay, silt and sand, their CEC values were between 1.02 meq/100g and 35.24 meq/100g. Mineral phases identified in the clayey samples include kaolinite, muscovite, hematite, goethite and quartz. The identified properties indicate that traditional usage of clays for body paintings by the Xhosas has scientific evidence which cannot be ignored.Keywords: Indigenous knowledge, Xhosa tribal rituals, clay properties