Southern Africa Research Articles

The burden of hospital-acquired infections (HAI) in sub-Saharan Africa: a systematic review and meta-analysis

Hospital-acquired infections (HAI) are a leading cause of morbidity and mortality globally. These infections are diverse, but the majority are lower respiratory tract infection (LRTI), surgical site infection (SSI), bloodstream infection (BSI), and urinary tract infection (UTI). For most sub-Saharan African countries, studies revealing the burden and impact of HAI are scarce, and few systematic reviews and meta-analysis have been attempted. We sought to fill this gap by reporting recent trends in HAI in sub-Saharan Africa (SSA) with attention to key patient populations, geographic variation, and associated mortality. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a literature search of six electronic databases (Web of Science, Pubmed, APA PsycInfo, CINAHL, Embase, and the Cochrane Library) to identify studies assessing the prevalence of HAI in SSA countries. Studies published between 01 January 2014 and 31 December 2023 were included. We applied no language or publication restrictions. Record screening and data extractions were independently conducted by teams of two or more reviewers. Using the R software (version 4.3.1) meta and metafor packages, we calculated the pooled prevalence estimates from random-effect meta-analysis, and further explored sources of heterogeneity through subgroup analyses and meta-regression. This study is registered with PROSPERO, CRD42023433271. Forty-one relevant studies were identified for analysis, consisting of 15 from West Africa (n=2107), 12 from Southern Africa (n=2963), 11 from East Africa (n=2142), and 3 from Central Africa (n=124). A total of 59.4% of the patient population were associated with paediatric admissions. The pooled prevalence of HAI was estimated at 12.9% (95% CI: 8.9-17.4; n=7336; number of included estimates [k]=41, p<0.001). By subregions, the pooled current prevalence of HAI in the West Africa, Southern Africa, East Africa and Central Africa were estimated at 15.5% (95% CI: 8.3-24.4; n=2107; k=15), 6.5% (95% CI: 3.3-10.7; n=2963; k=12), 19.7% (95% CI: 10.8-30.5; n=2142; k=11) and 10.3% (95% CI: 1.1-27.0; n=124; k=3) of the patient populations respectively. We estimated mortality resulting from HAI in SSA at 22.2% (95% CI: 14.2-31.4; n=1118; k=9). Our estimates reveal a high burden of HAI in SSA with significant heterogeneity between regions. Variations in HAI distribution highlight the need for infection prevention and surveillance strategies specifically tailored to enhance prevention and management with special focus on West and East Africa, as part of the broader global control effort. No funding was received for this study.

Phoenix ×arehuquensis nov. hybr. (Arecaceae): The hybrid of P. canariensis × P. reclinata in garden and forest

Phoenix reclinata Jacq. is a palm species native to tropical and southern Africa, extending to Madagascar, where its natural populations are exploited for sap and fibre. Widely embraced as an ornamental palm in gardens within warm zones abroad, it has established itself as an integral part of horticultural landscapes.On the other hand, Phoenix canariensis H. Wildpret is an endemic species found in the Canary Islands (Spain), forming extensive palm forests. Since the 1850s, it has emerged as the predominant ornamental Phoenix palm tree. Interestingly, in various regions, the natural habitat of one species intersects with cultivated individuals of the other. For instance, in southern Africa, where P. reclinata is indigenous and P. canariensis is exotic, occasional spontaneous hybrids have been reported. These hybrids have also been observed in Florida and California (USA), where both species are cultivated.In this publication, we formally introduce a new hybrid: Phoenix ×arehuquensis nov. hybr., originating from the Canary Islands. Additionally, we explore its potential impact on natural palm forests.

SeqCode facilitates naming of South African rhizobia left in limbo

South Africa is well-known for the diversity of its legumes and their nitrogen-fixing bacterial symbionts. However, in contrast to their plant partners, remarkably few of these microbes (collectively referred to as rhizobia) from South Africa have been characterised and formally described. This is because the rules of the International Code of Nomenclature of Prokaryotes (ICNP) are at odds with South Africa's National Environmental Management: Biodiversity Act and its associated regulations. The ICNP requires that a culture of the proposed type strain for a novel bacterial species be deposited in two international culture collections and be made available upon request without restrictions, which is not possible under South Africa’s current national regulations. Here, we describe seven new Mesorhizobium species obtained from root nodules of Vachellia karroo, an iconic tree legume distributed across various biomes in southern Africa. For this purpose, 18 rhizobial isolates were delineated into putative species using genealogical concordance, after which their plausibility was explored with phenotypic characters and average genome relatedness. For naming these new species, we employed the rules of the recently published Code of Nomenclature of Prokaryotes described from Sequence Data (SeqCode), which utilizes genome sequences as nomenclatural types. The work presented in this study thus provides an illustrative example of how the SeqCode allows for a standardised approach for naming cultivated organisms for which the deposition of a type strain in international culture collections is currently problematic.

Regional integration in Southern Africa: Evidence from the Southern African Development Community (SADC)

This article provides for an informative review on regional integration in Southern Africa by drawing lessons and evidence from the Souther African Development Community (SADC). It provides for a review of literature on the SADC from a regional integration perspective. SADC has expanded into a more expansive regional organisation in response to the challenges faced in the 1990s, and it currently includes South Africa, the region’s superpower. Furthermore, trade integration is receiving more attention, despite not being a main debate point at the Southern African Development Co-Ordinating Conference (SADCC). The SADC Trade Protocol has been decisive in trade integration. The purpose of the Protocol is to ensure that companies operating in each of the nations in the region may fairly compete to service the 150 million customers that comprise the market as a whole. It is anticipated that regional free trade will increase the likelihood of economic growth, increase intra-SADC commercial activity, create jobs, and elevate the standard of living for SADC residents.

Global spread, genetic differentiation and selection of barley spot form of net blotch isolates.

Spot form of net blotch, caused by Pyrenophora teres f. maculata, is a significant necrotrophic disease of barley that spread world-wide in the 20th century. Genetic relationships were analysed to determine the diversity, survival and dispersal of a diverse collection of 346 isolates from Australia, Southern Africa, North America, Asia Minor and Europe. The results, based on genome-wide DArTseq data, indicated isolates from Turkey were the most differentiated with regional sub-structuring, together with individuals closely related to geographically distant genotypes. Elsewhere, population subdivision related to country of origin was evident, although low levels of admixturing was found that may represent rare genotypes or migration from unsampled populations. Canadian isolates were the next most diverged and Australian and South African the most closely related. With the exception of Turkish isolates, multiple independent Cyp51A mutation events (which confer insensitivity to demethylation inhibitor fungicides) between countries and within regions was evident, with strong selection for a transposable element insertion at the 3' end of the promoter and counter-selection elsewhere. Individuals from Western Australia shared genomic regions and Cyp51A haplotypes with South African isolates, suggesting a recent common origin.

Good vibrations: remote‐tactile foraging success of wading birds is positively affected by the water content of substrates they forage in

Some taxa of wading birds can locate buried prey by detecting vibratory cues in their foraging substrates while probe‐foraging, using a sensory modality called ‘remote‐touch'. As more saturated substrates transmit vibrations better, we predict that these birds can detect prey in wetter substrates more easily. We used sensory assays to test whether substrate water content affects the remote‐touch foraging success rate of Hadeda ibises, Bostrychia hagedash. The birds were more successful at locating prey using vibratory cues than when relying on random direct contact with the beak alone. Their remote‐touch foraging success rate was positively affected by increasing water contents of the soil, but water content had no effect on their direct contact foraging success (indicating this is not an artefact of ease of probing). This may partially explain the link between the range expansion of this species in southern Africa and increased soil irrigation, as it is easier for the birds to detect prey in wetter substrates. Thus, it is likely that the distribution of other remote‐touch foraging birds is affected by substrate water content, and as many of these species are endangered and rely on sensitive wetland habitats, it is vital to understand their sensory requirements for foraging.

Antineoplastic Activity of Selected Cytotoxic Plants from the Kalahari

AbstractPlants are known to produce cytotoxic compounds, some of which are currently being used as chemotherapeutic agents for the treatment of cancer. With southern Africa’s rich biodiversity, it could be worthwhile to study indigenous herbal medicine to discover more effective and safe cancer treatments as complementary and alternative therapies. From Africa, several plant species have been used by traditional therapists for the treatment of cancer with well-known examples including Lessertia frutescens (L.) Goldblatt &amp; J.C.Manning (syn. Sutherlandia frutescence (L.) W:T.Aiton), Fabaceae, Catharanthus roseus (L.) G.Don, Apocynaceae, and Tulbaghia violacea Harv., Amaryllidaceae. Recently, Artemisia afra Jacq., Asteraceae, has also been shown to exhibit strong in vitro antineoplastic activity. This review focuses on A. afra and some lesser studied southern African plants from the Kalahari region. This selection was made based on field observations, traditional use, and literature summarizing recent developments and their potential as anticancer agents. Ammocharis coranica Herb., Amaryllidaceae, A. afra, Dipcadi glaucum (Burch. ex Ker Gawl.) Baker, Asparagaceae, Elephantorrhiza elephantina (Burch.) Skeels, Fabaceae, Geigeria ornativa O.Hoffm., Asteraceae, Neltuma juliflora (Sw.) Raf. (syn. Prosopis juliflora (Sw.) DC.), Fabaceae, and Senna italica Mill., Fabaceae, can be found in the Kalahari region stretching across three countries. Databases were consulted (Science Direct, Web of Science, Scopus, PubMed, and Google Scholar) and textbooks to collate scientific literature on the selected species. Lycorine seems to be the most promising bioactive compound isolated from A. coranica with in vitro cytotoxicity of 0.21 µg/ml (IC50). Methanol extracts of N. juliflora appear to be highly active, while butanolic extracts are cytotoxic at a low concentration of 5.17 µg/ml against MCF-7. Isoalantolactone identified in A. afra also expressed good activity, being cytotoxic at a low concentration of 1.89 µg/ml. Tea infusions of A. afra were found to be cytotoxic at 6.0 µg/ml with a selectivity index of 10. Identification of active constituents, more in-depth ex vivo/in situ experiments, and eventually clinical trials should be conducted on the most promising plant extracts and/or compounds identified therein. Graphical Abstract

Remote Midlatitude Control of Rainfall Onset at the Southern African Tropical Edge

Abstract Rainfall over the southern African tropical boundary is highly variable, particularly around the onset of the summer rains. However, understanding of the causes of variability in onset timing is poor. A lack of observational data in the region is compounded by the complexity of climate dynamics and variability at the interface of the tropics and the midlatitudes. The key to onset over the region is the Congo air boundary (CAB), a distinguishing circulation feature present in September and declining in frequency until November. The CAB is crucial to early season rainfall; precipitation is broadly inhibited when the CAB is present, while its breakdown allows large-scale rainfall and onset over central southern Africa. This work identifies a remote midlatitude influence on the timing of CAB breakdown using the high-resolution reanalysis dataset ERA5. Propagating and (upstream) breaking low-wavenumber Rossby waves in the Southern Hemisphere westerly jet are shown to be related to &gt;70% of breakdown events. Breakdown is forced by 1) the replacement of subsidence over eastern southern Africa with synoptically forced ascent and 2) wind field modification that leads to positive 850-hPa continental convergence anomalies and enhanced moisture advection from the Congo basin and Indian Ocean. Upper-level anticyclonic vorticity tendency induced by enhanced convection slows Rossby wave propagation aloft, contributing to wave breaking and the persistence of conditions favorable to convection. The identification of this midlatitude influence on CAB breakdown reveals new potential sources of predictability for onset and demonstrates the significant equatorward extent of midlatitude influences to the tropical edge. Significance Statement This study aims to improve our understanding of the causes of variability in the start date of the summer rainy season in central southern Africa. The research reveals that certain upper-level waves in the Southern Hemisphere westerly jet are associated with patterns of weather that force a large-scale transition from dry pre-onset conditions to widespread rainfall in a time scale of 2–5 days, and that these waves account for a large proportion of such transitions. This finding is of interest to subseasonal weather forecasters and may help to improve the long-range forecasting of onset date.

Thinking Africa through Soga’s black spirituals: A theological reflection

This article offers a critical reflection of Lizal’isidinga laKho (hymn 116) and Wazidala iinto zonke (hymn 16) written by Tiyo Soga and recorded in the Methodist Church of Southern Africa (MCSA) hymnal book. From the perspective of black theology of liberation (BTL), I historicise and contextualise hymn 116 and hymn 16 to debunk the argument that Tiyo Soga was alien to the lives, experiences of suffering and pain of his people. The article posits that hymn 116 and hymn 16 are black spirituals that articulate the contexts Soga found himself as a black person during the times of the frontier wars. Therefore, utilising blackness as a heuristic approach, I argue that the songs do not just historicise the experiences of black people in the times of the frontier wars, but they are prayers and/or laments from Soga that ask God to spare the lives, the culture, and value systems of black people in a world that seeks the destruction of their being, history, and culture. The songs emphasise the black struggle for justice and liberation encouraging black people never to succumb to the definitions given to them by those who seek the destruction of black personhood. The article locates Soga within the frontier wars to illustrate his own experiences as black person, then examines and presents Lizal’isidinga laKho, Wazidala iinto zonke as black spirituals born in a time of war to give hope to those who have been conquered and subjugated in the unjust wars of colonisation. Hymns 116 and 16 contribute to the decolonial turn discourse –unthinking of the west – because they emphasise the black struggle for liberation and justice.Contribution: The contribution of this article is its focus on the way in which the intersection of religious studies, social sciences, and humanities generates an interdisciplinary contested discourse.

Made in Africa: Tapestry and the Topography of Swedish Philanthropy in Southern Africa

ABSTRACT During the 1960s, tapestries from Swedish art and craft centres in southern Africa were acclaimed in the Nordic country as an outcome of its own expertise and largesse. Yet when these works by marginalised women artists in Africa were exhibited at the National Museum in Stockholm in 1970, they were dismissed as the fruits of Swedish cultural imperialism and naive artistic minds. Despite the ensuing public debate, the exhibition and its discourses, like the works themselves, are little known in southern Africa and now largely forgotten in Sweden. In considering the visual vocabularies of some of these tapestries, many of which were woven at the renowned centre at Rorke’s Drift in KwaZulu-Natal, this article addresses the implications of these Swedish ‘culture-rescue’ projects, showing how women’s artistic ‘voices’ on the subcontinent were silenced, not merely by apartheid suppression but also in Swedish representations. By interrogating the attitudes that the audiences of the exhibitions held towards black women artists, the article reveals how the tapestries’ woven iconographies were a complex response to circumstance, covertly interrogating white hegemony while invested with self-definition.

Host tree-based scenario modelling for predicting a key edible insect, mopane worm Gonimbrasia belina (Westwood, 1894) distribution in Southern Africa

Abstract Gonimbrasia belina, known as the mopane worm, is a large edible caterpillar in tropical and subtropical regions. However, little is known about the bioecology of this species as influenced by its host trees. This study evaluated the importance of different potential host trees in understanding mopane worms’ behaviour and spatial distribution. To assess their relative importance, the study compared models incorporating various mopane worm host trees and predictor variables. Using the species distribution modelling (SDM) package in R, an ensemble of random forest (RF), support vector machine (SVM), and boosted regression tree (BRT) algorithms were used to assess the spatial extent of mopane worm distribution in Southern Africa. Four host tree-based scenarios were developed to assess their contribution to the relative distribution of the mopane worm i.e. (1) by excluding all the potential host trees as explanatory variables and considering only the environmental variables, (2) focusing on the primary host tree, Colophospermum mopane as an explanatory variable together with the other environmental variables, (3) incorporating all the host trees, including C. mopane and (4) examining all other host trees excluding C. mopane. Results demonstrated that incorporating all host trees enhanced the models’ predictive abilities (mean AUC = 0.87) underscoring the significant impact of the alternative host trees on the mopane worm distribution patterns beyond just the C. mopane. This study highlights the significance of host trees in predicting the behaviour and distribution of mopane worm populations, providing valuable insights and decision-making for mopane worm use as an alternative protein source, conservation efforts, and land management practices.

Multistakeholder regional dialogues as catalysers for transboundary water cooperation

ABSTRACT Multistakeholder dialogues (MSDs) provide unique opportunities for partners and key stakeholders to meet in a neutral space, get to know each other, and build trust and mutual understanding before getting into the issue of water cooperation. The study identifies four key enabling factors stimulating regional MSDs: (a) balancing inclusion and role of facilitators, (b) utilizing existing regional political and economic processes, (c) using thematic anchoring and strategic design, and (d) leveraging sustainable finance. An examination of transboundary regional MSDs in South East Europe, Southern Africa, and South Asia reveals the pivotal role played by these four factor.

Rock engravings marking the Redan landscape in Gauteng, South Africa

The ontological1 and epistemological2 foundations of reality, myths, beliefs, and practices in ritual behaviour have long been studied by scholars around the globe. There is no single understanding and representation of reality, as all that is real or existent within the universe is historically shaped by interdependent cultural and social processes and fear factors. Although the study of rock art is primary a branch of archaeology, cultural history also focuses on a past time and place, to study beliefs and ideas from a bottom-up approach and include the objects and experiences (sometimes unwritten) of the everyday life of the uneducated and less privileged. It is particularly well equipped to offer an understanding of the San myths, beliefs, ritual practices, and modes of representation of reality, as represented in their rock art. The Redan open-air rock engraving site is located on the Kookfontein farm, near the former Klip power station at Redan, close to a wetland that was formerly a rivulet that founded its way to the Klip River, a tributary of the Vaal River. The Klip-Vaal area is situated in the southern part of Gauteng, South Africa. Being part of the Late Stone Age hunting, domestic and ritual sites of the San people and later migrants it contains numerous documented and undocumented rock art sites. In line with interpretivism, the methodology is based on published and unpublished literature, as well as several on-site inspections of the site between 2002 and 2022. Authorship of the engravings at the Redan site is unconfirmed, although two dominant views regarding the cultural origin have emerged, namely a San hunter-gatherer shamanistic approach and the Koranna-Khoekhoen initiation site hypothesis.Contribution: The article contributes to the neglected historiography of the rock engravings in the Klip-Vaal region, in particular the Redan site, and the need to facilitate a comparison with similar rock engravings in southern Africa.

Behind the waterfall - Interdisciplinary results from Holley Shelter and their implications for understanding human behavioral patterns at the end of the Middle Stone Age in southern Africa

Holley Shelter is a Middle (MSA) and Later Stone Age (LSA) site in KwaZulu-Natal, South Africa. The rock shelter is located at the intersection of three ecosystems, in a strip of the Savanna Biome between the Grassland and Indian Ocean Coastal Belt Biomes. Initial excavations in the 1950s by Gordon Cramb yielded large amounts of unifacial points and splintered pieces, as well as organic remains associated with MSA occupations. Our comparative techno-typological evaluation of this material in 2015 suggested the occupations may date to early MIS 3. We then initiated new excavations at the site using modern field methods and controlled sampling for lithic and organic material. Following the initial round of interdisciplinary analysis, we herein report the first absolute ages for Holley Shelter, a detailed technological analysis of new lithic material from the uppermost MSA layers at the site, and a preliminary study of the associated faunal remains. A set of 12 14C dates place these occupations within a constricted chronological period dated to ∼36,000–34,000 cal. BP that overlaps with the so-called ‘final MSA’. The hornfels-dominated lithic assemblages are characterized by diverse core technologies oriented toward the production of laminar products, which include bladelets and abundant splintered pieces. The zooarchaeological analysis documents an emphasis on open grasslands that provided the bulk of the animal prey exploited by the inhabitants of the shelter, with a preference for medium-sized antelopes. Three bone retouchers, a rare occurrence in southern African MSA contexts, were identified in the faunal assemblage. The archaeological deposits at Holley Shelter reflect short-term, potentially seasonal, and specialized occupations that could be influenced by its ecological position. The archaeological material exhibits marked discrepancies with other well-dated final MSA assemblages such as those from Sibhudu, Umbeli Belli, Sibebe and Border Cave. This illustrates considerable variability and a complex spatio-temporal patterning of behavioral adaptations and cultural traditions at the end of the MSA in southern Africa.

On Colonial Monuments in the Post-colony: An Outline of the Problems of Populist Approaches in Managing Heritage in Southern Africa

What to do with colonial-era monuments has been a major challenge facing southern African nations ever since the demise of colonialism and apartheid in the subregion. To deal with the problem, governments in the region embarked on popular transformative agendas that included decontextualization and the removal of alleged problematic monuments from the public sphere. Such approaches have over the years received the backing of several scholars of heritage and history, who have often cited them as ones capable of offering ever-ending solutions to the issue. However, while recognizing the necessity of transformation, this article nevertheless argues that such a transformative agenda that is characterized by erasures of that which has been accepted as heritage in a particular phase of a country’s history is not a proper way of dealing with such symbols. First, such approaches create possibilities for heritage fundamentalism to filter into the domain of heritage. Second, such approaches were premised on the narrow argument that the notion of problematic heritage is only limited to cases of racial differences or between the former colonizers and the colonized. Instead, by using examples of case studies in one of the countries in the region, the article demonstrates that all heritage is subject to review, either by new political dispensations or by future generations. Hence, when dealing with symbols accepted as heritage, interpretation as opposed to decontextualization or destruction must be resorted to as a guiding framework. When this happens, heritage then ceases to be a platform of contestation and becomes one of continuity.

Unravelling the maternal evolutionary history of the African leopard (Panthera pardus pardus).

The African leopard (Panthera pardus pardus) has lost a significant proportion of its historical range, notably in north-western Africa and South Africa. Recent studies have explored the genetic diversity and population structure of African leopards across the continent. A notable genetic observation is the presence of two divergent mitochondrial lineages, PAR-I and PAR-II. Both lineages appeared to be distributed widely, with PAR-II frequently found in southern Africa. Until now, no study has attempted to date the emergence of either lineage, assess haplotype distribution, or explore their evolutionary histories in any detail. To investigate these underappreciated questions, we compiled the largest and most geographically representative leopard data set of the mitochondrial NADH-5 gene to date. We combined samples (n = 33) collected in an altitudinal transect across the Mpumalanga province of South Africa, where two populations of leopard are known to be in genetic contact, with previously published sequences of African leopard (n = 211). We estimate that the maternal PAR-I and PAR-II lineages diverged approximately 0.7051 (0.4477-0.9632) million years ago (Ma). Through spatial and demographic analyses, we show that while PAR-I underwent a mid-Pleistocene population expansion resulting in several closely related haplotypes with little geographic structure across much of its range, PAR-II remained at constant size and may even have declined slightly in the last 0.1 Ma. The higher genetic drift experienced within PAR-II drove a greater degree of structure with little haplotype sharing and unique haplotypes in central Africa, the Cape, KwaZulu-Natal and the South African Highveld. The phylogeographic structure of PAR-II, with its increasing frequency southward and its exclusive occurrence in south-eastern South Africa, suggests that this lineage may have been isolated in South Africa during the mid-Pleistocene. This hypothesis is supported by historical changes in paleoclimate that promoted intense aridification around the Limpopo Basin between 1.0-0.6 Ma, potentially reducing gene flow and promoting genetic drift. Interestingly, we ascertained that the two nuclear DNA populations identified by a previous study as East and West Mpumalanga correspond to PAR-I and PAR-II, respectively, and that they have come into secondary contact in the Lowveld region of South Africa. Our results suggest a subdivision of African leopard mtDNA into two clades, with one occurring almost exclusively in South Africa, and we identify the potential environmental drivers of this observed structure. We caution that our results are based on a single mtDNA locus, but it nevertheless provides a hypothesis that can be further tested with a dense sample of nuclear DNA data, preferably whole genomes. If our interpretation holds true, it would provide the first genetic explanation for the smaller observed size of leopards at the southernmost end of their range in Africa.

The radiative impact of biomass burning aerosols on dust emissions over Namibia and the long-range transport of smoke observed during the Aerosols, Radiation and Clouds in southern Africa (AEROCLO-sA) campaign

Abstract. The radiative effects of biomass burning aerosols (BBAs) on low-level atmospheric circulation over southern Africa are investigated on 5 September 2017 during the Aerosols, Radiation and Clouds in southern Africa (AEROCLO-sA) field campaign. This is conducted using a variety of in situ and remote sensing observations, as well as two 5 d ensemble simulations made with the Meso-NH mesoscale model, one including the direct and semi-direct radiative effects of aerosols and one in which these effects are not included. We show that the radiative impact of BBA building up over a period of 5 d in the Meso-NH simulations can lead to significantly different circulations at low and middle levels, thereby affecting dust emissions over southern Namibia and northwestern South Africa as well as the transport of BBA in a so-called “river of smoke”. While most of the regional-scale dynamics, thermodynamics and composition features are convincingly represented in the simulation with BBA radiative effects, neglecting the radiative impact of BBA leads to unrealistic representations of (i) the low-level jet (LLJ) over the plateau, which is the main low-level dynamic feature fostering dust emission, and (ii) the mid-level dynamics pertaining to the transport of BBA from the fire-prone regions in the tropics to the mid-latitudes. For instance, when the BBA radiative impacts are not included, the LLJ is too weak and not well established over night, and the developing convective planetary boundary layer (PBL) is too deep compared to observations. The deeper convective PBL over Etosha and surrounding areas is related to the enhanced anomalous upward motion caused by the eastern displacement of the river of smoke. This eastern displacement is, in turn, related to the weaker southerly African easterly jet. Both ensemble simulations provide clear evidence that the enhanced near-surface extinction coefficient values detected from observations over Etosha are related to the downward mixing of BBA in the developing convective boundary layer rather than dust being emitted as a result of the LLJ breakdown after sunrise. This study suggests that the radiative effect of BBAs needs to be taken into account to properly forecast dust emissions in Namibia.

Using Euler Deconvolution as Part of a Mineral Exploration Project

Mineral exploration projects can make considerable use of a variety of geophysical techniques and datasets, including magnetic and gravity data. The interpretation of large quantities of data can be very time consuming, so semi-automatic interpretation techniques are often used to provide initial estimates of the parameters (primarily the location and depth) of the sources of anomalies. Euler deconvolution is a commonly used interpretation method for potential fields which has a number of advantages over many other techniques, such as working in the presence of remanent magnetisation, and not being restricted to a particular model such as a contact. A second-order version of Euler’s equation is introduced here, which is much less affected by trends in the data than the standard method and additionally produces depth parabolas, which simplify the interpretation of results. The method was applied to aeromagnetic data from a mineral exploration project in Southern Africa and provided plausible results.

The Quadrangular Cartilage in Rhinoplasty: A surgically focused CT dimensional analysis of Black African and Caucasian populations.

The apparent lack of quadrangular cartilage in Black African noses is commonly observed both from a radiological and clinical point of view. To the best of our knowledge only a few research papers has been conducted on the facial proportions and structural anatomy of black people of Southern and Eastern Africa. The aim of this retrospective comparative study is a radiological assessment of the total amount of septal quadrangular cartilage by measuring its area in sagittal CT views, in two selected Black South African (SA) and Caucasian (CA) samples and the comparison with the literature in our hands. Statistical analysis was conducted, Categorical variables are showed as frequencies and percentages, while continuous variables as means and standard deviations (SD). Normal distribution of variables was verified using the Shapiro-Wilk test or by means of skewness and kurtosis values. Differences among unpaired groups were evaluated using the independent Student's t test for normally distributed data (complemented by the Cohen's d to show the effect size with the following cut-off: d=0.2, "small" effect size; d=0.5, "medium" effect size; d=0.8, "large" effect size) and Mann-Whitney U test in case of no normal distribution. Statistical significance was defined as p <0.05 setting the α-error probability at 5%. This study shows that on average there is a 30% more cartilage available in caucasian compared to Black African noses and confirms the apparent lack of quadrangular cartilage and in Black African noses which is commonly observed in surgery. The need for an adequate amount of autologous septal cartilage makes cartilage availability a major concern before surgery and being able to pre-operative accurately measure the amount of septal cartilage that is available to be harvested for other grafts in the surgery is essential.

Invasion risk of the currently cultivated alien flora in southern Africa is predicted to decline under climate change

Alien species can have massive impacts on native biodiversity, ecosystem functioning, and human livelihoods. Assessing which species from currently cultivated alien floras may escape into the wild and naturalize is essential for efficient and proactive ecosystem management and biodiversity conservation. Climate change has already promoted the naturalization of many alien plants in temperate regions, but whether it is similar in (sub)tropical areas is insufficiently known. In this study, we used species distribution models for 1527 cultivated alien plants to evaluate current and future invasion risks across different biomes and 10 countries in southern Africa. Our results confirm that the area of suitable climate is a strong predictor of naturalization success among the cultivated alien flora. In contrast to previous findings from temperate regions, however, climatic suitability is generally predicted to decrease for potential aliens across our (sub)tropical study region. While increasingly hotter and drier conditions are likely to drive declines in suitability for potential aliens across most biomes of southern Africa, in some the number of potential invaders is predicted to increase under moderate climate change scenarios (e.g. in dry broadleaf forests and flooded grasslands). We found that climatic suitability is expected to decline less for aliens originating from continents with the tropical biome or from the Southern Hemisphere. In addition, we found that the climatically suitable area will decline less for aliens that have already naturalized in the region. While the number of potential invaders may decrease across southern Africa under future climate change, our results suggest that already naturalized aliens will continue to threaten native species and ecosystems.