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1.
Food from fungi     
If and when economic conditions and technological advances become favorable, fungi may some day be significant in furnishing human food through their protein-synthesizing capacity. The yeast, Torulopsis, has already been utilized on a commercial scale in this direction in Germany, Jamaica, South Africa, India, California and Wisconsin.  相似文献   

2.
Despite an on-going struggle to conserve the endangered black rhinoceros (Diceros bicornis) since the 1980s, huge capital investment and several genetic surveys, the level of genetic structure and connectivity among populations in southern Africa is not well understood. Here, we undertake a major population genetic study of black rhinoceros in the Zimbabwe Lowveld, an area inhabited by over half of that country’s original Zambezi descendants plus one large population sourced from the relict KwaZulu stock of South Africa. Using nuclear microsatellite and mitochondrial DNA data, we found much higher levels of genetic diversity in the indigenous Zimbabwean populations, where observed multilocus heterozygosity was 0.54 versus 0.40 in KwaZulu, and maternal haplotype diversity was 0.77 versus 0.03. We show, for the first time, that both gene pools can be differentiated from each other on the basis of nuclear markers. This, along with the discovery of recent gene flow between all Lowveld populations, suggests that Zimbabwean and South African gene pools were prehistorically connected.  相似文献   

3.
While wage labour and money have received much anthropological attention, the same cannot be said of wages themselves – actual banknotes and coins distributed in workforces. This article traces wages' social productivity among farm workers on the Zimbabwean‐South African border. In this migrant‐labour setting, money's form matters. Because currency objects are physically the same, it is difficult for workers to store them in an insecure environment, leading them to turn to one another. As they manage their earnings, workers attempt to establish themselves as social persons while maintaining future options in uncertain circumstances. Workforce ties both shape and are constituted by flows of cash and the rhythms and circuits of the wage. Seen in terms of form, wages are highly personal – the very stuff of sociality.  相似文献   

4.
5.
Abstract

Folk conceptualizations of racism can be defined as ordinary people's understandings of the sources and persistence of racism. They function as equalization strategies – by denying the legitimacy of racism – and guide beliefs regarding antiracism strategies. I explore folk explanations of racism among black professionals in Brazil and South Africa by drawing on sixty interviews with members of these groups. In Brazil, racism is understood as an historical lingering, a product of ignorance, which will disappear with time and education. In South Africa, racism is viewed as more resilient, as a part of human nature and as a consequence of the competition for resources. These explanations of racism are closely related to the antiracism narratives that are salient in these two contexts: while Brazilian respondents affirm their belief in racial mixture and moral education, South African respondents are more uncertain about the possibilities of weaker racial boundaries in their country, relying on institutional constraints as their main antiracism strategy.  相似文献   

6.
7.
Attempts to investigate the drivers of invasion success are generally limited to the biological and evolutionary traits distinguishing native from introduced species. Although alien species introduced to the same recipient environment differ in their invasion intensity – for example, some are “strong invaders”; others are “weak invaders” – the factors underlying the variation in invasion success within alien communities are little explored. In this study, we ask what drives the variation in invasion success of alien mammals in South Africa. First, we tested for taxonomic and phylogenetic signal in invasion intensity. Second, we reconstructed predictive models of the variation in invasion intensity among alien mammals using the generalized linear mixed‐effects models. We found that the family Bovidae and the order Artiodactyla contained more “strong invaders” than expected by chance, and that such taxonomic signal did not translate into phylogenetic selectivity. In addition, our study indicates that latitude, gestation length, social group size, and human population density are only marginal determinant of the variation in invasion success. However, we found that evolutionary distinctiveness – a parameter characterising the uniqueness of each alien species – is the most important predictive variable. Our results indicate that the invasive behavior of alien mammals may have been “fingerprinted” in their evolutionary past, and that evolutionary history might capture beyond ecological, biological and life‐history traits usually prioritized in predictive modeling of invasion success. These findings have applicability to the management of alien mammals in South Africa.  相似文献   

8.
The coelacanth, Latimeria chalumnae, occurs at the Eastern coast of Africa from South Africa up to Kenya. It is often referred to as a living fossil mainly because of its nearly unchanged morphology since the Middle Devonian. As it is a close relative to the last common ancestor of fish and tetrapods, molecular studies mostly focussed on their phylogenetic relationships. We now present a population genetic study based on 71 adults from the whole known range of the species. Despite an overall low genetic diversity, there is evidence for divergence of local populations. We assume that originally the coelacanths at the East African Coast derived from the Comoros population, but have since then diversified into additional independent populations: one in South Africa and another in Tanzania. Unexpectedly, we find a split of the Comoran coelacanths into two sympatric subpopulations. Despite its undeniably slow evolutionary rate, the coelacanth still diversifies and is therefore able to adapt to new environmental conditions.  相似文献   

9.
Hybridisation is the interbreeding of genetically distinct groups that can lead to introgression – an exchange of genetic material between species. Hybridisation is of conservation concern when an alien invasive species is involved, as it can lead to a loss of local genetic adaptations and genetic diversity. Hybridisation is a significant threat for many dabbling ducks where interbreeding with the closely related invasive Mallard Anas platyrhynchos is extremely common. Phenotypic evidence suggests that Mallard populations in South Africa hybridise with the indigenous Yellow-billed Duck Anas undulata. The aim of this study was to determine the incidence of hybridisation between Yellow-billed Ducks, occurring in central and northwestern South Africa, and introduced Mallards. Genetic variation between Mallards, Yellow-billed Ducks, and their inferred hybrids was assessed using mitochondrial and microsatellite DNA markers. All samples inferred to be hybrids based on the phenotype were found to have Yellowbilled Duck mitochondrial DNA and showed minimal evidence of admixture across the microsatellite markers. Thus, these results do not support the notion that hybridisation between Mallards and Yellow-billed Ducks is prevalent in central and northwestern South Africa. However, hybridisation could be occurring where Mallards are found in higher abundance, such as in the Western Cape Province. Therefore, continued monitoring of this potential hybridisation should be performed frequently and throughout South Africa.  相似文献   

10.
Assessment of water footprint sustainability indicators and economic water productivities is regarded as a cornerstone of the world’s sustainability goal and the reduction of the fresh water scarcity risk. These assessments are gaining much prominence because about four billion people face severe water scarcity, globally. Attaining sustainable and economically efficient water use goals requires a thorough assessment of all the existing sectors that use water. This paper examined the water footprint and economic water productivities of dairy products in South Africa for the periods 1996–2005 and 2006–2013 using the water footprint network assessment methodology. We found the total water footprints of all the selected dairy products in South Africa to be higher than the global averages are. During the period of 1996–2005, South African dairy producers utilized more green water in their dairy production. The production of butter and cheese products, whether grated or not grated, powdered or not powdered, blue-veined and cheese of all kinds had the highest total water footprints among all the dairy products in South Africa. Dairy production under a sole grazing system has high water footprints and low economic water productivities, relative to mixed production systems, for the period 2006–2013. With blue water becoming scarcer in South Africa, it is time for dairy livestock producers to shift their production to a system that is highly productive and has low water footprints. The water footprints of most of the dairy products for period 2006–2013 have reduced by varying amounts, relative to 1996–2005, which shows that water users along the dairy industry chains are managing water cautiously. Our findings have revealed dairy products that have high economic water productivities, and suggest that profit maximising and environmentally sustainable dairy producers and water users should integrate both blue water sustainability and economic water productivity indicators in their production decisions.  相似文献   

11.
The economic transition in developing countries is not always the result of the change from a centrally-planned to a free-market economy, but may be found within an already existing free-market economy as a result of profound political change, as in South Africa. The release of Nelson Mandela in February 1990 heralded an end both to the political system of apartheid and to the concomitant social, political, and economic disenfranchisement of 30 million non-White people in South Africa. The first freely elected non-White government came to power in 1994 and initiated a number of social and economic reforms aimed at alleviating the worst consequences of apartheid. This paper examines the effect of post-apartheid economic and social transition on the growth and development of urban children. Over 4000 children born in Soweto and Johannesburg were enrolled in the Birth to Ten (BTT) birth-cohort study in 1990. Whilst these children were born with lower birth weights than in developed countries, they did grow strongly in infancy, particularly in weight, to reflect normal reference values for body mass index (BMI) by 1 year of age. While post-apartheid social and economic changes were expected to take some time to affect child growth and development, the rate of change has been slower than expected. Data from the BTT study demonstrate that the growth of White children continues to be superior to that of their non-White peers and differences that existed at birth and during infancy have not diminished during childhood and early adolescence. Whatever factors are changed at the national or community levels during economic (and social) transition in South Africa appear not yet to have resulted in improved child physical growth.  相似文献   

12.
Newly-moulted adults of three Rhipicephalus appendiculatus stocks, originating from Kenya, Zambia and Zimbabwe, were kept in different photoperiods (12h : 12h, 13h : 11h and 14h : 10h light : dark). The stock originating from Kenya showed almost no behavioural diapause in any of these day lengths, whereas virtually all individuals of the Zimbabwean stock entered a behavioural diapause irrespective of day length. Adults from the Eastern Province of Zambia, a transition zone between the multivoltine phenology in equatorial Africa and the univoltine in southern Africa, exhibited a photoperiod-dependent diapause response. The possible mechanisms of diapause regulation and their origin are discussed.  相似文献   

13.
ABSTRACT

The many studies that see shopping malls as places of power, control and exclusion have often neglected the potential of malls as places of encounters. Drawing on ethnographic data from the divided cities of Johannesburg in South Africa and Mostar in Bosnia–Herzegovina, we examine the ways in which urban dwellers who enter the mall from a marginalised position – poor black urban dwellers at a regional, middle class and white-dominated mall in Johannesburg and Bosniak city dwellers at a mall located in the Croat part of Mostar – use the mall, what kind of relations they build to others and how they rework boundaries of race, class, religion and ethnicity at the mall. Rather than being spaces that strengthen and reproduce centre–margins relations, urban dwellers appropriate them as places where these relations become reworked.  相似文献   

14.
Aim Although sharing many similarities in their vegetation types, South America and Africa harbour very dissimilar recent mammal faunas, not only taxonomically but also in terms of several faunistic patterns. However late Pleistocene and mid‐Holocene faunas, albeit taxonomically distinct, presented many convergent attributes. Here we propose that the effects of the Holocene climatic change on vegetation physiognomy has played a crucial role in shaping the extant mammalian faunistic patterns. Location South America and Africa from the late Pleistocene to the present. Methods Data presented here have been compiled from many distinct sources, including palaeontological and neontological mammalian studies, palaeoclimatology, palynology, and publications on vegetation ecology. Data on Pleistocene, Holocene and extant mammal faunas of South America and Africa allowed us to establish a number of similar and dissimilar faunistic patterns between the two continents across time. We then considered what changes in vegetation physiognomy would have occurred under the late Pleistocene last glacial maximum (LGM) and the Holocene climatic optimum (HCO) climatic regimes. We have ordained these proposed vegetation changes along rough physiognomic seral stages according to assumptions based on current botanical research. Finally, we have associated our hypothesized vegetation changes in South America and Africa with mammalian faunistic patterns, establishing a putative causal relationship between them. Results The extant mammal faunas of South America and Africa differ widely in taxonomical composition; the number of medium and large species they possess; behavioural and ecological characteristics related to herbivore herding, migration and predation; and biogeographical patterns. All such distinctions are mostly related to the open formation faunas, and have been completely established around the mid‐Holocene. Considering that the mid‐Holocene was a time of greater humidity than the late Pleistocene, vegetation cover in South America and Africa would have been dominated by forest or closed vegetation landscapes, at least for most of their lower altitude tropical regions. We attribute the loss of larger‐sized mammal lineages in South America to the decrease of open vegetation area, and their survival in Africa to the existence of vast savannas in formerly steppic or desertic areas in subtropical Africa, north and south of the equator. Alternative explanations, mostly dealing with the disappearance of South American megamammals, are then reviewed and criticized. Main conclusions The reduction of open formation areas during the HCO in South America and Africa explains most of the present distinct faunistic patterns between the two continents. While South America would have lost most of its open formations within the 30° latitudinal belt, Africa would have kept large areas suitable to the open formation mammalian fauna in areas presently occupied by desert and semi‐arid vegetation. Thus, the same general climatic events that affected South America in the late Pleistocene and Holocene also affected Africa, leading to our present day faunistic dissimilarities by maintaining the African mammalian communities almost unchanged while dramatically altering those of South America.  相似文献   

15.
Africa horse sickness (AHS) is a lethal disease of horses with a seasonal occurrence that is influenced by environmental conditions that favor the development of Culicoides midges (Diptera: Ceratopogonidae). This study compared and evaluated the relationship of various modeled climatic variables with the distribution and abundance of AHS in South Africa and Namibia. A comprehensive literature review of the historical AHS reported data collected from the Windhoek archives as well as annual reports from the Directorate of Veterinary services in Namibia were conducted. South African AHS reported data were collected from the South African Department of Agriculture, Forestry, and Fisheries. Daily climatic data were extracted for the time period 1993–2011 from the ERA‐interim re‐analysis dataset. The principal component analysis of the complete dataset indicated a significant statistical difference between Namibia and South Africa for the various climate variables and the outbreaks of AHS. The most influential parameters in the distribution of AHS included humidity, precipitation, evaporation, and minimum temperature. In South Africa, temperature had the most significant effect on the outbreaks of AHS, whereas in Namibia, humidity and precipitation were the main drivers. The maximum AHS cases in South Africa occurred at temperatures of 20–22° C and relative humidity between 50–70%. Furthermore, anthropogenic effects must be taken into account when trying to understand the distribution of AHS.  相似文献   

16.
Semimytilus patagonicus is an invasive mussel on the coast of southern Africa and has extended its range in recent years. We asked whether its distribution and abundance are consistent with the abundant-centre hypothesis (ACH). Marginal populations were located by monitoring 33 rocky shore sites in South Africa and southern Namibia in 2021. This revealed no changes to its distributional limits since 2020. At nine of these sites, population demography was measured to allow a comparison of their densities and size structure. Four were central populations on the west coast of South Africa (including the site where the species was first detected in 2009). Four were marginal populations in South Africa: two towards the cold range edge in the north and two towards the warm range edge to the south. The ninth population was in southern Namibia, representing a recent invasion event first detected in 2014. Across the species' South African range, the distribution of its abundance was generally consistent with the ACH, with the greatest abundance at its range centre and a gradual decrease towards the range edges. However, the ultimate marginal population at both its cold and warm range edges showed moderate upticks in abundance compared to the penultimate marginal populations. Additionally, marginal populations in South Africa typically included a greater proportion of large individuals. Recruitment intensity was greater in warm range edge populations than cold range edge populations. The size structure of the population in Namibia resembled those of central populations in South Africa. Moderate increases in densities at the absolute range limits suggest that the species is currently undergoing spread into regions associated with moderately optimal environmental conditions (ultimate range edge sites) after encountering regions associated with suboptimal environmental conditions (penultimate range edge sites).  相似文献   

17.
The South African government is committed to science and technology innovation, to establishing a knowledge-based economy and to harnessing life-sciences research for health and economic development. Given the constraints and the early stage of development of the field as a whole in South Africa, we found an impressive amount of research on human genomic variation in this country. Encouragingly, South Africa is beginning to apply genomics to address local health needs, including HIV and tuberculosis (TB) infections. We document a number of initiatives in South Africa that are beginning to study genetic variation within the various local indigenous populations. Other early initiatives focus on pharmacogenetic studies, mutation characterization in individual disease genes and genome-wide association studies. Public engagement in genomic issues is spear-headed by The Africa Genome Education Institute.  相似文献   

18.
In 2010, South Africa hosted the first World Cup in soccer ever to take place on the African continent. Twenty years after the fall of Apartheid, South Africa presents a series of fractured and contradictory images to the outside world. It is, on the one hand, an economic powerhouse in sub-Saharan Africa, but on the other hand a society in which socio-economic inequalities have continued to flourish and increase. What can anthropology tell us about contemporary South Africa? As part of an ongoing series in public anthropology, Professor Thomas Hylland Eriksen and Postdoctoral Fellow Sindre Bangstad sat down for a public conversation with Professors John L. and Jean Comaroff in The House of Literature in Oslo, Norway, on 28 September 2010.  相似文献   

19.
Originally prepared as a keynote address for the 2008 La Tapoa Workshop on Natural Resource Management (NRM) and Community Based Natural Resource Management (CBNRM), this paper examines the Southern African experience in CBNRM over the past 20 years. From this experience the paper draws lessons on when and where CBNRM is appropriate, what can make it work, and what can make it work better. These lessons are discussed under the three categories of benefit, conservation and empowerment. Benefit is usually conceptualized in terms of financial revenue, and using a Zimbabwean case study the paper shows how in unusual circumstances this can be substantial. Normally, however, natural resource production can only supplement inputs from agriculture and other modes of production, and the paper warns against regarding CBNRM as a panacea for rural poverty. Benefit should also be understood in non-pecuniary terms, and when economic benefit is linked with authority and responsibility large increments in social capital can result. The conservation interests of donors are often perceived as being at odds with local perspectives, a perception which fails to take into consideration means-end-sequencing. A socially constructed stalemate often occurs when external agencies impose their agendas upon local populations, a stalemate which can be broken when communities are given the authority and responsibility necessary to create internally legitimate regimes. A new science which combines professional and civil inputs is required to achieve CBNRM’s goal—empowered and dynamic local regimes integrated into larger scale systems of conservation and development.  相似文献   

20.
Reproduction is a crucial part of the successful establishment and spread of an invasive species. Invasive plants often produce seeds prolifically to spread into new ranges, yet the invasive macrophyte, Pontederia cordata L., does not appear to produce seeds in South Africa, limiting its invasive potential. Here, we aimed to determine what limits seed production of the tristylous P. cordata in South Africa, where it is widespread with impacts on the ecology of wetlands it invades, South Africa. We measured floral traits and pollen grain size from populations throughout the invasive range in South Africa to determine the relative proportion of tristylous morphs. We speculated that the absence of specialist native pollinators in the invasive range may be responsible for the absence of sexual reproduction and thus conducted a pollination study to determine whether flowers were visited. Thereafter, we hand pollinated 8865 flowers to conclude whether P. cordata exhibited an incompatibility system, which prevented seed production. The floral traits and pollen grain measurements were similar to those reported for short‐morphed flowers from the native range. The pollination study confirmed the absence of specialist insect visitors, while the hand‐pollination experiments resulted in no seed production. Only short‐morphed plants are present in South Africa, and the illegitimate pollination of short‐morphed plants prevents seed production. Vegetative spread through rhizome production is thus responsible for the invasion of P. cordata throughout South Africa. These findings suggest that control programs should target the plants'' rhizomes to prevent and reduce spread. More importantly, preventing the introduction of medium‐ and long‐morphed plants into South Africa is crucial to preclude P. cordata from producing seeds and enhancing invasion.  相似文献   

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