Transactions of the Royal Society of South Africa - latest Issue
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Volume 72, Issue 1, 2017
Source: Transactions of the Royal Society of South Africa 72, pp 1 –5 (2017) http://dx.doi.org/10.1080/0035919X.2016.1209701More Less
The aim of the study was to assess the consequences of sand mining activities on soil erosion, vegetation clearance and landslide levels in the O.R. Tambo district. The study setting included Mngazi, Chwebeni and Coffee Bay sand mining sites. Soil erosion was defined by donga width and donga depth. Landslides constitute a form of erosion. An open pit confirmed current mining activity. Clearing of vegetation and areas covered by alien vegetation were also considered to be the environmental consequences of anthropogenic activities. Communities, policy makers and managers should be engaged in environmental awareness campaigns. It is also recommended that sand mining sites should be sited outside sensitive environments.
Petrogenetic processes in granitic magmas and their igneous microgranular enclaves from Central Victoria, Australia : match or mismatch?Source: Transactions of the Royal Society of South Africa 72, pp 6 –32 (2017) http://dx.doi.org/10.1080/0035919X.2016.1209702More Less
Using chemical evidence, particularly the variations between titanium and iron + magnesium, we demonstrate that the petrogenetic processes that operated within Central Victorian granitic host magmas and their igneous microgranular enclave suites are dissimilar. Chemical variations within the granitic series result from a variety of what might be called ‘orderly’ processes, resulting in linear or curvilinear trends in chemical variation diagrams. Those that affected the enclave suites commonly resulted in scattered, chaotic variations. Even in cases where an enclave suite displays a more orderly chemical variation, it is demonstrable that the hypothesis of simple mixing between an enclave magma and a host granitic magma, to bring about the overall chemical variations, cannot be supported. The enclave magmas had vastly smaller volumes compared with their host granitic magmas. Thus, they have commonly undergone hybridisation through mixing with deep crustal melts and both chemical and mechanical interactions with wall rocks and their enclosing granitic magmas. As a result of this complex and chaotic set of processes, it remains extremely difficult to unravel the precise mechanisms that produced a given suite of enclave magmas. Due to the similarities between the studied granites and their enclaves with occurrences worldwide, we suggest that our findings are likely to have general applicability.
Evaluation of cytotoxic effects and antimicrobial activities of Lecaniodiscus cupanioides (Planch.) leaf extractSource: Transactions of the Royal Society of South Africa 72, pp 33 –38 (2017) http://dx.doi.org/10.1080/0035919X.2016.1214851More Less
The present study assessed the cytotoxic and antimicrobial activities of Lecaniodicus cupanioides leaf extract, evaluated its killing rate and also determined the presence of certain phytochemicals. The antimicrobial activities were assessed via a susceptibility test and by determination of minimum bacteriotastic and bactericidal concentrations. The killing rate was evaluated at regular intervals over a 2h-period under different concentrations and the cytotoxicity was measured through a brine shrimp lethality test. Zones of inhibition exhibited by the extract at 20 mg/ml ranged between 20±0.00 and 23±0.58 mm against both bacteria and yeast isolates. The inimum inhibitory concentrations (MICs) were between 1.25 and 2.50 mg/ml against bacteria and 0.63 and 1.25 mg/ml against yeasts. The minimum bactericidal concentrations (MBCs) ranged from 2.50 to 5.00 mg/ml (bacteria) and 1.25 to 2.5 mg/ml (yeasts). At a concentration of 1×MIC after 15 min of contact time, the mortality against Shigella sonnei (ATCC 29930), Staphylococcus aureus (ATCC 6538) and Candida albicans as representative isolates were 52.3, 60.0 and 40.0%, respectively. Total mortality was achieved against S. sonnei (ATCC 29930) at a concentration of 2×MIC after 120 min of contact time while that of S. aureus (ATCC 6538) was achieved after 90 min of contact time at 3×MIC. Percentage mortality against the C. albicans after 120 min under a concentration of 3×MIC was 94.4%. The lethality concentrations at LC50 and LC90 of the leaf extract were 4.255 and 36.766 μg/ml, respectively. The results obtained support the therapeutic significance of L. cupanioides leaf extract and could be a veritable source of affordable broad spectrum antimicrobial and anti-tumour agent.
Source: Transactions of the Royal Society of South Africa 72, pp 39 –46 (2017) http://dx.doi.org/10.1080/0035919X.2016.1218373More Less
Minimum temperatures and frost are ecologically and agriculturally important parameters as they can cause mortality in plants and livestock, shape the position of biome boundaries, influence the lifecycles of pests and diseases, and influence the availability and quality of livestock feed. This study examines minimum temperature data from 1916 to 2014 for a site on the Nama-Karoo/Grassland biome ecotone. Temperatures of at least −6 °C occur almost every year, while temperatures of below −10 °C occurred in 15 of the years on record. Temperature data did not exhibit a random pattern, but rather showed the period from 1935 to 1960 to be particularly cold in terms of absolute minimum temperatures, the probability of occurrence of frost and the duration of the dormant (frost) season. The results provide a platform for interpretation for ecological and agricultural processes that have been recorded in several long-term trials at Grootfontein. The patterns of variation in the data indicate that short (c. 50-year) temperature datasets may give misleading indications in trends in temperature, and for an empirically based interpretation of climate change, long-term datasets of approximately a hundred years are needed.
Source: Transactions of the Royal Society of South Africa 72, pp 47 –54 (2017) http://dx.doi.org/10.1080/0035919X.2016.1229698More Less
The objective of this study was to determine the concentration of trace elements in soils of Keana-Awe brine-fields. Composite soil samples were randomly collected at a depth of 0–15 cm and were analysed for molybdenum, zinc, arsenic, lead, cobalt, chromium, copper, barium and nickel using Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). Quantification of the degree of soil contamination by these trace elements was carried out using the enrichment factor (EF) and the geo-accumulation index (Igeo). The data were subjected to principal component analysis (PCA). The average concentrations were 1.56 ppm molybdenum, 1116.42 ppm zinc, 23.80 ppm arsenic, 71.40 ppm lead, 17.64 ppm cobalt, 237.35 ppm chromium, 24.16 ppm copper, 254.67 ppm barium and 143.71 ppm nickel. Cobalt, nickel and chromium showed positive loadings in component 1 with a total variance of 29.56%. Zinc, copper and lead showed positive loadings in component 2 with a total variance of 18.79%, while copper showed negative loading in component 3 with a total variance of 14.79%. Considering the concentration of trace elements in the soils and statistical analyses, we conclude that soils of the study area were severely enriched in molybdenum, cobalt, chromium, copper, barium, nickel, while arsenic and zinc are in excessive concentrations in the soils. These trace elements could have originated from geogenic and anthropogenic sources.
Source: Transactions of the Royal Society of South Africa 72, pp 55 –62 (2017) http://dx.doi.org/10.1080/0035919X.2016.1258015More Less
Although similar methodologies are applied within different scientific disciplines, each subject is constrained to work within limits imposed by the types of measurements that are possible and the systematic trends discerned within these observations. Ellis has recognised a hierarchy within scientific subjects in which “exact science”, exemplified by physics, has become generally accepted as “more fundamental” than other sciences (e.g. geology). Inferences about geological conditions that yield particular rock types, minerals, etc., must be based on examinations of products of natural changes, now inaccessible to experimental replication and verification. Thus, science subjects do not form a continuum: each is distinctive in both methodology and achievable objectives, discontinuously distinguished in these respects from neighbours within the hierarchy. Science can, therefore, be described as quantised.
We discuss here two instances in which the perceived superior authority of one subject (physics) seriously impeded progress of a “junior partner” (geology). Around 1870, Lord Kelvin calculated the Earth’s age as less than a hundred million years, insufficient time to evolve the existing fauna, including humans. The unknown factor omitted from this calculation was heat evolved by radioactive element decay (physics!), making Lord Kelvin’s estimate much too short. Some decades later, Wegener’s proposal of continental drift was originally opposed by physicists, though subsequently an agreed physical explanation was found. The discontinuities separating adjoining sciences are, on occasion, difficult to bridge, so that advances in the less exact discipline suffer disproportionately. We conclude, therefore, that in interdisciplinary research, all available observational evidence should be appraised equitably.
Author Milton ShainSource: Transactions of the Royal Society of South Africa 72, pp 63 –74 (2017) http://dx.doi.org/10.1080/0035919X.2016.1258016More Less
This paper explores D.F. Malan’s attitudes towards the Jews in the context of burgeoning Afrikaner nationalism and the challenge of the radical right in the 1930s and 1940s. Beginning with the Quota Act of 1930, Malan increasingly expressed hostility towards Jews. Fuelled by opposition towards German-Jewish immigration and subsequently calling for limitations on Jewish occupations and opportunities in South Africa, Malan denied any anti-Jewish animus. Yet his rhetoric was increasingly shrill through the 1930s. Was Malan simply an opportunist or was he genuinely hostile? While opportunism was a feature of his political style, and while some of his attacks were in all likelihood politically driven, too often he appeared consumed by imaginary Jewish machinations. Nevertheless, it needs to be acknowledged that Malan turned away from the “Jewish Question” soon after World War II and refused to kowtow to those wishing to maintain anti-Jewish policies.
Cytotoxicity, antimicrobial and antidiarrhoeal activities of standardised aqueous root extract of Elephantorrhiza elephantina (Burch.)Source: Transactions of the Royal Society of South Africa 72, pp 75 –84 (2017) http://dx.doi.org/10.1080/0035919X.2016.1259687More Less
Elephantorrhiza elephantina is used in Basotho traditional medicine to treat infectious diseases including diarrhoea. This study evaluated its aqueous extract for cytotoxicity, antimicrobial and antidiarrhoeal activities. While brine shrimp lethality assay was used for the cytotoxicity study, the antimicrobial activity was determined via a micro-plate dilution method. Using castor oil, and gastrointestinal motility models, the antidiarrhoeal activity was also investigated. The extract inhibited all the tested bacterial and Candida strains at minimum inhibitory concentrations of 0.78–3.13, and 0.78–1.56 mg/mL, respectively. For the antidiarrhoeal study, the extract dose dependently and significantly prolonged the onset time of diarrhoea, decreased the characteristic faeces features, increased intestinal Na+-K+- ATPase activity, attenuated nitric oxide content and effectively inhibited gastrointestinal motility in experimental animals. In all the antidiarrhoeal models, the extract (at 400 mg/kg) elicited effects that compared favourably with loperamide (standard drug). Judging by the LC50 value of 42.04 μg/mL for the cytotoxicity assay, the extract could be adjudged highly potent and effective. The results from the present study have not only presented E. elephantina as being endowed with chemotherapeutic constituents which could be potentially useful for the development of drugs against bacterial infections, but also validate its Basotho traditional application against diarrhoea.
Source: Transactions of the Royal Society of South Africa 72, pp 85 –92 (2017) http://dx.doi.org/10.1080/0035919X.2016.1259689More Less
Ezemvelo KwaZulu-Natal Wildlife embarked on a programme to identify all the estuaries within the KwaZulu-Natal (KZN) province. Following an aerial survey along the coastline in 2012, images of all the visible inlets and estuaries were captured. Among these are a number of areas where flows of freshwater to the sea appeared to be present but which were not among the estuaries that had previously been named. There are already well defined and recognised estuary types being managed in South Africa in terms of existing environmental legislation. Following the initial survey and the observation that there are coastal inlets/freshwater outlets that are potentially small estuaries that had not been included among them prompted a further investigation into whether some of these inlets were in fact features that should be classified in some way or other. Based on a rapid qualitative assessment, 181 sites were classified as either a “micro-estuary”, “freshwater seep”, “hard-structure freshwater outflow point” or as sites that had been considerably modified by engineered structures. A total of 61 of these 181 sites are included in a new classification as micro-estuaries. Most of these systems are in a degraded condition and require intensive rehabilitation to restore them to their historical ecological function. This study emphasises the urgency of accepting “micro-estuary” as a new estuarine type to provide formal protection against further deterioration. This is the first study to provide a description and spatially define these smaller systems present along the KZN coast.
Author Michal SingerSource: Transactions of the Royal Society of South Africa 72, pp 93 –94 (2017) http://dx.doi.org/10.1080/0035919X.2016.1262925More Less
The focus of Milton Shain’s A Perfect Storm: Antisemitism in South Africa: 1930–1948 is the shifting presence of antisemitism in South African politics and its contribution to the formulation of racial political discourse between the 1930s and 1940s. Shain provides a masterful reconstruction of the racialised zeitgeist in South Africa that emerged in these critical years. The book begins with the findings of the Carnegie Commission and promulgation of the Quota Act in 1930, and ends with the declining influence of antisemitism in South African politics following the war. Having emerged within the peculiar paradigm of Afrikaner volk identity politics, the look and feel of this anti-Jewish prejudice was moulded according to this political economy. Through the resurgence of both archaic and modernist anti-Jewish tropes, including international Jewish “money power” and the biblical supposition that the Jews were responsible for the crucifixion of Jesus Christ, antisemitism fitted easily into “the new discourse of race and culture” dominating South African politics. With semantic precision, this discourse targeted Jews through the opaque concept of “unassimilability”. European Jews were considered to be racially incompatible with the white population of South Africa, and this served as the basis for legal measures to curb immigration. The South African government thus “conveniently dodged the taint of antisemitism” in its policy
Exploring a Sub-Antarctic Wilderness: A Personal Narrative of the First Biological and Geological Expedition to Marion and Prince Edwards Islands 1965/1966, Brian J. HuntleyAuthor Bernadette HinceSource: Transactions of the Royal Society of South Africa 72, pp 95 –96 (2017) http://dx.doi.org/10.1080/0035919X.2016.1266413More Less
The subantarctic islands of the southern Indian Ocean, South Atlantic and Southern Oceans constitute about 22 islands or island groups. Most are not permanently inhabited, the Falkland Islands being a notable exception. The islands, all claimed by various more or less remote parent nations, are sodden, windblown, cold, and seldom visited, yet are held in the greatest affection by almost everyone who has seen them.
Author Edward SturrockSource: Transactions of the Royal Society of South Africa 72, pp 97 –102 (2017) http://dx.doi.org/10.1080/0035919X.2016.1274922More Less
The International Council for Science declared 2016 the International Year of Global Understanding. The aim of this initiative was to promote a better understanding of how the local impacts the global to more effectively tackle critical challenges such as climate change and food security. The main focus was how to translate scientific insight into more sustainable lifestyles and thus the topics for our School Science Essay Competition this year were highly appropriate. By challenging the young minds of our country on relevant issues we are able to harness the imagination and energy of the scientists and leaders of tomorrow in order to shape a sustainable future.
Why it is important to study and understand human origins from an environmental, biological and cultural perspective, Chloe van Niekerk
What advances in robotics and artificial intelligence could impact on youth employment in South Africa, Michael Noyce
Author Gerrit PienaarSource: Transactions of the Royal Society of South Africa 72, pp 103 –104 (2017) http://dx.doi.org/10.1080/0035919X.2017.1295593More Less
The recent death of Professor Andre van der Walt on 5 November 2016 has left a huge and tragic void, not only among the South African legal community, but also worldwide among constitutional property lawyers. He was one of only a few constitutional lawyers in the world with extensive knowledge of the South African property clause and related constitutional matters, as well as property clauses worldwide.