Verdien Homo naledi ‘n plek in ons familie-album? ‘n Teologiese besinning oor die evoluering van spiritualiteit met spesifieke verwysing na die begraafplaasteorie van Lee Berger en die ‘Rising-Star’-ekspedisie

The discovery of a new homonin species called Homo naledi evoked unprecedented interest, even outside the scientific disciplines who are researching extinct homonin species. The reason for this is that Prof. Lee Berger, attached to the University of the Witwatersrand and his team, known as the Rising Star-expedition, came to the conclusion that the fossils that were discovered in the Dinaledi cave room in Sterkfontein outside Johannesburg in 2013, were placed there deliberately. The theory postulates the possibility of symbolic or ritual behaviour by a species that lived and later became extinct approximately 1 to 2 million years ago. If this is indeed the case, it also offers theologians the opportunity to join the conversation with regard to the evolvement of our spirituality and religiousness. This article is an attempt to render a contribution, with the data available to us, about the value of the prehistoric signs of spirituality with specific reference to the so-called cemetery theory. Together with this, other usable theories will be employed to consider the possible signs of ritual and symbolic behaviour by Homo naledi. The condition for a meaningful discussion about the evolvement of our spirituality and religiousness is that epistemological contours be clearly drawn. With the first part of the article these contours are drawn and with the second part the possible implications of the cemetery theory are reviewed.This research is part of the project, ‘Contextualized Reformed Theology in South Africa’, directed by Dr Andre Ungerer of the Reformed Theological College, Faculty of Theology, University of Pretoria.http://www.hts.org.zaam2018Reformed Theological Colleg

Atmospheric dry and wet deposition of sulphur and nitrogen species and assessment of critical loads of acidic deposition exceedance in South Africa

We tested the hypothesis that acidic atmospheric pollution deposition, originating from the South African central industrial area, poses an environmental threat across a larger region within the dispersal footprint. A network of 37 passive monitoring sites to measure SO2 and NO2 was operated from August 2005 to September 2007. The area extended over the entire northern and eastern interior of South Africa. Monitoring locations were chosen to avoid direct impacts from local sources such as towns, mines and highways. Dry deposition rates of SO2 and NO2 were calculated from the measured concentrations. Concentrations of sulphur and nitrogen species in wet deposition from a previous study were used in conjunction with measured rainfall for the years 2006 and 2007 to estimate the wet deposition over the region. The calculated total (non-organic) acidic deposition formed the basis for an assessment of exceedance of critical loads based on sensitivity of the regional soils. Regional soil sensitivity was determined by combining two major soil attributes available in the World Inventory of Soil Emission Potentials (International Soil Reference and Information Centre). Results indicate that certain parts of the central pollution source area on the South African Highveld have the potential for critical load exceedance, while limited areas downwind show lower levels of exceedance. Areas upwind and remote areas up and downwind, including forested areas of the Drakensberg escarpment, do not show any exceedance of the critical loads

Spatial and temporal assessment of organic and black carbon at four sites in the interior of South Africa

Limited data currently exist for atmospheric organic carbon (OC) and black carbon (BC) in South Africa (SA). In this paper OC and BC measured in SA were explored in terms of spatial and temporal patterns, mass fractions of the total aerosol mass, as well as possible sources. PM10 and PM2.5 samples were collected at five sites in SA operated within the Deposition of Biogeochemical Important Trace Species-IGAC DEBITS in Africa (DEBITS-IDAF) network. OC were higher than BC concentrations at all sites in both size fractions, while most OC and BC occurred in the PM2.5 fraction. OC/BC ratios reflected the location of the different sites, as well as possible sources impacting these sites. The OC and BC mass fraction percentages of the total aerosol mass varied up to 24% and 12%, respectively. A relatively well defined seasonal pattern was observed, with higher OC and BC measured from May to October, which coincides with the dry season in the interior of SA. An inverse seasonal pattern was observed for the fractional mass contributions of OC and BC to the total aerosol mass, which indicates substantially higher aerosol load during this time of the year. The relationship between OC and BC concentrations with the distance that air mass back trajectories passed by biomass burning fires and large point sources proved that biomass burning fires contribute significantly to regional OC and BC during the burning season, while large point sources did not contribute that significantly to regional OC and BC. The results from a highly industrialised and populated site also indicated that household combustion for space heating contributed at least to local OC and BC concentrations

South African EUCAARI measurements: seasonal variation of trace gases and aerosol optical properties

In this paper we introduce new in situ observations of atmospheric aerosols, especially chemical composition, physical and optical properties, on the eastern brink of the heavily polluted Highveld area in South Africa. During the observation period between 11 February 2009 and 31 January 2011, the mean particle number concentration (size range 10–840 nm) was 6310 cm−3 and the estimated volume of sub-10 μm particles 9.3 μm3 m−3. The aerosol absorption and scattering coefficients at 637 nm were 8.3Mm−1 and 49.5Mm−1, respectively. The mean single-scattering albedo at 637 nm was 0.84 and the A° ngstro¨m exponent of scattering was 1.5 over the wavelength range 450–635 nm. The mean O3, SO2, NOx and H2S-concentrations were 37.1, 11.5, 15.1 and 3.2 ppb, respectively. The observed range of concentrations was large and attributed to the seasonal variation of sources and regional meteorological effects, especially the anticyclonic re-circulation and strong winter-time inversions. In a global context, the levels of gases and particulates were typical for continental sites with strong anthropogenic influence, but clearly lower than the most polluted areas of southeastern Asia. Of all pollutants observed at the site, ozone is the most likely to have adverse environmental effects, as the concentrations were high also during the growing season. The measurements presented here will help to close existing gaps in the ground-based global atmosphere observation system, since very little long-term data of this nature is available for southern Africa.JRC.H.7-Climate Risk Managemen

Risk factors for Coronavirus Disease 2019 (COVID-19) death in a population cohort study from the Western Cape Province, South Africa

BACKGROUND. Risk factors for coronavirus disease 2019 (COVID-19) death in sub-Saharan Africa and the effects of human immunodeficiency virus (HIV) and tuberculosis on COVID-19 outcomes are unknown. METHODS. We conducted a population cohort study using linked data from adults attending public-sector health facilities in the Western Cape, South Africa. We used Cox proportional hazards models, adjusted for age, sex, location, and comorbidities, to examine the associations between HIV, tuberculosis, and COVID-19 death from 1 March to 9 June 2020 among (1) public-sector “active patients” (≥1 visit in the 3 years before March 2020); (2) laboratory-diagnosed COVID-19 cases; and (3) hospitalized COVID-19 cases. We calculated the standardized mortality ratio (SMR) for COVID-19, comparing adults living with and without HIV using modeled population estimates. RESULTS. Among 3 460 932 patients (16% living with HIV), 22 308 were diagnosed with COVID-19, of whom 625 died. COVID- 19 death was associated with male sex, increasing age, diabetes, hypertension, and chronic kidney disease. HIV was associated with COVID-19 mortality (adjusted hazard ratio [aHR], 2.14; 95% confidence interval [CI], 1.70–2.70), with similar risks across strata of viral loads and immunosuppression. Current and previous diagnoses of tuberculosis were associated with COVID-19 death (aHR, 2.70 [95% CI, 1.81–4.04] and 1.51 [95% CI, 1.18–1.93], respectively). The SMR for COVID-19 death associated with HIV was 2.39 (95% CI, 1.96–2.86); population attributable fraction 8.5% (95% CI, 6.1–11.1). CONCLUSIONS. While our findings may overestimate HIV- and tuberculosis-associated COVID-19 mortality risks due to residual confounding, both living with HIV and having current tuberculosis were independently associated with increased COVID-19 mortality. The associations between age, sex, and other comorbidities and COVID-19 mortality were similar to those in other settings.The Western Cape Provincial Health Data Centre from the Western Cape Department of Health, the US National Institutes for Health (grant numbers R01 HD0804, the Bill and Melinda Gates Foundation, the United States Agency for International Development and the Wellcome Trust.https://academic.oup.com/cid/am2023Veterinary Tropical Disease

The adsorption of tungsten(VI) on activated carbon from 1.0 M Na(H)Cl solution

The adsorption of tungsten(VI) onto activated carbon has been investigated as a function of pHc in the range 2.0-6.5 at constant ionic strength (1 M NaCl) and temperature (25°C). The tungsten concentration was varied from 5 × 10-4 to 2 × 10-2 M. Adsorption is very strong at pHc < 4.5 and depending on equilibrium conditions, loadings of ∼ 2.8 mM WVI per g activated carbon can be obtained. Computer treatment of distribution data led to an adsorption model, similar to that proposed (J. J. Cruywagen and H. F. de Wet, Polyhedron 1988, 7, 547) for molybdenum(VI), comprising mainly dimeric species and small amounts of monomeric species. The chemisorption is explained in terms of complexation of tungsten(VI) with basic oxygen atoms at the surface of the activated carbon. Adsorption constants of tungsten and molybdenum correlate well with complex formation constants of tungsten and molybdenum with oxalate and citrate. © 1988.Articl

A kinetic and mechanistic study of the chromium (VI) reduction by hydrogen peroxide in acidic aqueous solutions

The reduction of hexavalent chromium, Cr(VI), by hydrogen peroxide in both buffered and non-buffered aqueous solutions was investigated as a function of concentration, pH, ionic strength, effect of radical scavengers, temperature and pressure. The rate of the reaction between Cr(VI) and hydrogen peroxide exhibited a strong dependence on the pH of the reaction mixture, viz. a decrease in reaction rate with increasing pH from 1.0 to 7.0. For a 2.5 x 10-4 mol·dm-3 Cr(VI) solution, a H2O2 concentration of at least 10 times the initial Cr(VI) concentration was required for complete reduction in this pH range. Neither the ionic strength of the reaction mixture, nor the presence of a radical scavenger had an effect on the rate of the ratedetermining step. From the temperature dependence of the reaction the activation enthalpy (ΔH≠) was calculated to be 10.4 ± 0.5 kJ·mol-1 and the activation entropy (ΔS≠) to be -186 ± 3 J K-1·mol-1 for the rate-determining step. The volume of activation (ΔV≠) was found to be -6.1 ± 0.5 cm3 ·mol-1 from the pressure dependence of the reaction rate. The empirical data could be fitted to: kobs = k[H+][H2O2]/(Ka + [H+]), with k = (48.4 ± 1.4) x 103 dm3·mol-1·s-1 and Ka the acid dissociation constant of H2CrO4. A reaction mechanism in which a Cr(VI)/H2O2 adduct is formed in the rate determining step, is proposed. The theoretical rate law that can be derived from this mechanism is in agreement with the empirical rate law.Keywords: kinetics, mechanism, chromium (VI), reduction, hydrogen peroxide, activation parameter

Radiative impact of the Carbonaceous aerosol over the African continent : optical efficiencies comparison between MesoNH-C simulations and SAFARI2000 aerosol products.

(14-16 septembre 2004

Long-term observations of aerosol size distributions in semi-clean and polluted savannah in South Africa

This study presents a total of four years of sub-micron aerosol particle size distribution measurements in the southern African savannah, an environment with few previous observations covering a full seasonal cycle and the size range below 100 nm. During the first 19 months, July 2006–January 2008, the measurements were carried out at Botsalano, a semi-clean location, whereas during the latter part, February 2008–May 2010, the measurements were carried out at Marikana (approximately 150 km east of Botsalano), which is a more polluted location with both pyrometallurgical industries and informal settlements nearby. The median total concentration of aerosol particles was more than four times as high at Marikana than at Botsalano. In the size ranges of 12–840 nm, 50–840 nm and 100–840 nm the median concentrations were 1856, 1278 and 698 particles cm−3 at Botsalano and 7805, 3843 and 1634 particles cm−3 at Marikana, respectively. The diurnal variation of the size distribution for Botsalano arose as a result of frequent regional new particle formation. However, for Marikana the diurnal variation was dominated by the morning and evening household burning in the informal settlements, although regional new particle formation was even more frequent than at Botsalano. The effect of the industrial emissions was not discernible in the size distribution at Marikana although it was clear in the sulphur dioxide diurnal pattern, indicating the emissions to be mostly gaseous. Seasonal variation was strongest in the concentration of particles larger than 100 nm, which was clearly elevated at both locations during the dry season from May to September. In the absence of wet removal during the dry season, the concentration of particles larger than 100 nm had a correlation above 0.7 with CO for both locations, which implies incomplete burning to be an important source of aerosol particles during the dry season. However, the sources of burning differ: at Botsalano the rise in concentration originates from regional wild fires, while at Marikana domestic heating in the informal settlements is the main source. Air mass history analysis for Botsalano identified four regional scale source areas in southern Africa and enabled the differentiation between fresh and aged rural background aerosol originating from the clean sector, i.e., western sector with very few large anthropogenic sources. Comparison to size distributions published for other comparable environments in Northern Hemisphere shows southern African savannah to have a unique combination of sources and meteorological parameters. The observed strong link between combustion and seasonal variation is comparable only to the Amazon basin; however, the lack of long-term observations in the Amazonas does not allow a quantitative comparison. All the data presented in the figures, as well as the time series of monthly mean and median size distributions are included in numeric form as a Supplement to provide a reference point for the aerosol modelling community