scholarly journals Antigenic relationship of West Nile strains by titre ratios calculated from cross-neutralization test results

1987 ◽  
Vol 99 (2) ◽  
pp. 551-557 ◽  
Author(s):  
N. K. Blackburn ◽  
D. L. Thompson ◽  
P. G. Jupp
Keyword(s):  
South African ◽  
Prototype Strain ◽  
Antigenic Relationship ◽  
Test Results ◽  
The South ◽  
West Nile ◽  
Indian Strain ◽  
Relationship Of ◽  
Prior Infection ◽  
Prototype Virus

SUMMARYThe antigenic relationship of ten South African West Nile isolates, the South African prototype virus H442, the Egyptian strain EG101 and the Indian strain G2266 were compared using titre ratios. The titre ratios or ‘R’ values were calculated from heterologous and homologous neutralization titres and expressed as a percentage.Substantial antigenic differences were demonstrated between the South African prototype strain and the majority of the recently obtained South African isolates, seven of which were fairly closely related and possibly form a distinct antigenic sub-set. The recent isolates also differed from the Egyptian and Indian West Nile isolates. The heterologous results between the South African West Nile strains and the Indian strain G2266 suggest that prior infection with an Indian West Nile virus would give poor protection against the South African viruses, whereas the reverse would not be so.

Unraveling the South African Breast Cancer Story: The Relationship of Patients, Delay to Diagnosis, and Tumor Biology With Stage at Presentation in an Urban Setting

2019 ◽  
Vol 235 ◽  
pp. 181-189
Author(s):  
Sarah Rayne ◽  
Kathryn Schnippel ◽  
Surbhi Grover ◽  
Kirstin Fearnhead ◽  
Deirdre Kruger ◽  
...  
Keyword(s):  
Breast Cancer ◽  
South African ◽  
Tumor Biology ◽  
Urban Setting ◽  
The South ◽  
Relationship Of ◽  
The Relationship

Thuranthos: notes on generic status, morphology, phenology and pollination biology

Bothalia ◽  
1976 ◽  
Vol 12 (1) ◽  
pp. 161-165 ◽  
Author(s):  
C. H. Stirton
Keyword(s):  
South African ◽  
Field Studies ◽  
Pollination Biology ◽  
Fruit Morphology ◽  
The South ◽  
Generic Status ◽  
Additional Information ◽  
Relationship Of ◽  
First Time ◽  
The Relationship

The generic status of Thuranthos C. H. Wr. is discussed. A key separating the two species is provided. The genus is reported to occur in Natal for the first time. Field studies in Natal have yielded additional information on the habitat, phenology, fruit morphology and pollination biology of  T. macranthum (Bak.) C.H. Wr. Phalaenophily is reported for the second time in the South African Liliaceae. The relationship of T. macranthum with the moth  Diaphone eumela (Cramer)—Noctuidae, Hadeniae, is discussed.

Blood and breath alcohol test results: Uncertainty at the interface of science and law

2021 ◽  
Vol 138 (3) ◽  
pp. 535-568
Author(s):  
J B Laurens ◽  
P A Carstens ◽  
J B Laurens ◽  
L G Curlewis
Keyword(s):  
Measurement Uncertainty ◽  
South African ◽  
Due Process ◽  
Road Traffic ◽  
Test Results ◽  
The South ◽  
Scientific Principles ◽  
Process Perspective ◽  
National Road ◽  
Alcohol Testing

Alcohol is well known for its ability to impair human faculties, which creates risks when driving a vehicle or when performing safety- and risk-sensitive tasks in workplaces. The article aims to highlight some shortcomings in the legal-scientific approach for alcohol testing in South Africa. In particular, we investigate the measurement uncertainty of blood alcohol test results, which is critical in adjudicating over-the-limit cases. The South African regulatory framework for alcohol testing in the criminal- and private-law environments is examined from an analytical due-process perspective, considering measurement uncertainty and other well-established scientific principles which are essential at the interface of science and law. Special attention is paid to the National Road Traffic Amendment Bill, which aims to decrease the alcohol limit to zero. We found that the measurement uncertainty concept has not yet been received into the South African legal system, even though it is a well-established scientific principle. We suggest changes to the current alcohol legislation to accommodate the measurement uncertainty principle and the related likelihood ratio, which we believe could assist in quantifying the odds of compliance. In particular, we believe that our suggestions regarding quantification and reporting of measurement uncertainty can assist the courts and tribunals to avoid false-positive errors that may have a devastating effect on innocent subjects.

scholarly journals Volatility dynamics and the risk-return relationship in South Africa: A GARCH approach

2021 ◽  
Vol 18 (2) ◽  
pp. 106-117
Author(s):  
Nitesha Dwarika ◽  
Peter Moores-Pitt ◽  
Retius Chifurira
Keyword(s):  
South Africa ◽  
Parameter Estimation ◽  
South African ◽  
Risk Estimation ◽  
Probability Distributions ◽  
Financial Data ◽  
Test Results ◽  
Sample Period ◽  
The South ◽  
Risk Return

This study is aimed at investigating the volatility dynamics and the risk-return relationship in the South African market, analyzing the FTSE/JSE All Share Index returns for an updated sample period of 2009–2019. The study employed several GARCH type models with different probability distributions governing the model’s innovations. Results have revealed strong persistent levels of volatility and a positive risk-return relationship in the South African market. Given the elaborate use of the GARCH approach of risk estimation in the existing finance literature, this study highlighted several weaknesses of the model. A noteworthy property of the GARCH approach was that the innovation distributions did not affect parameter estimation. Analyzing the GARCH type models, this theory was supported by the majority of the GARCH test results with respect to the volatility dynamics. On the contrary, it was strongly unsupported by the risk-return relationship. More specifically, it was found that while the innovations of the EGARCH (1, 1) model could account for the volatile nature of financial data, asymmetry remained uncaptured. As a result, misestimating of risks occurred, which could lead to inaccurate results. This study highlighted the significance of the innovation distribution of choice and recommended the exploration of different nonnormal innovation distributions to aid with capturing the asymmetry.

scholarly journals The variability in commercial laboratory aggregate testing for road construction in South Africa

2021 ◽  
Vol 63 (1) ◽  
Author(s):  
I J Breytenbach ◽  
H G Fourie
Keyword(s):  
South African ◽  
Construction Material ◽  
Road Construction ◽  
Test Results ◽  
The South ◽  
Commercial Laboratory ◽  
Rock Aggregate ◽  
Water Absorption Test ◽  
Project Data ◽  
Aggregate Crushing

Simple data comparisons were undertaken using project data to illustrate the need for duplicate test analyses in road construction material investigations for hard rock aggregate sources. Test data was sourced from projects commissioned by the South African National Roads Agency SOC Limited (SANRAL). All test results except the polished stone value were reported by commercial geotechnical laboratories that are accredited with the South African National Accreditation System (SANAS). Only samples subjected to duplicate test analyses were used, as this method allows direct comparisons. The tests used for comparison included the polished stone value, wet and dry versions of the Aggregate Crushing Value test, wet and dry versions of the 10% Fines Aggregate Crushing Value test, the ethylene glycol-soaked version of the 10% Fines Aggregate Crushing Value test, and the water absorption test of both the fine (-5.00 mm) and coarse (+5.00 mm) material fractions. The results show that duplicate testing is firmly justified, as test results reported were often highly variable, despite all participating laboratories being SANAS-accredited and using standardised methods. Further consideration was then given to the additional cost of duplicate testing at project stage investigations compared to the cost implications of having erroneously reported materials failing in service or having good-quality materials rejected.

scholarly journals South Africa-BRIC-SADC Trade Alliances and the South African Economy

2018 ◽  
Vol 55 (1) ◽  
pp. 61-74
Author(s):  
Adrino Mazenda ◽  
Tyanai Masiya ◽  
Norman Nhede
Keyword(s):  
South Africa ◽  
South African ◽  
Price Index ◽  
Consumer Price Index ◽  
Cost Of Living ◽  
The South ◽  
Negative Contribution ◽  
Long Run ◽  
Relationship Of ◽  
Positive Results

The article discusses the implications of South Africa-Brazil Russia India China-Southern African Development Community (BRIC-SADC) trade alliances on South Africa’s economic growth. The analysis follows the periods in which South Africa is mired by fluctuating exchange rate and rising cost of living, as denoted by the rising consumer price index (CPI). In order to understand the implications, an autoregressive redistributive modelling (ARDL) was utilized on quarterly data from 2005 quarter 1 to 2017 quarter 3, regressing South Africa’s growth against South Africa-BRIC and South Africa-SADC trade balances, the main variables of interest. The empirical results identify a significant long-run relationship of the selected variables. However, the results review a negative contribution of South Africa-BRIC trade on South Africa’s economy, while the South Africa-SADC trade produced positive results. Trade composition remains a major challenge for South Africa-BRIC trade. Continued innovation and research and development will shift reliance on primary commodities for exports to mechanized products, hence increasing gains from the lucrative BRICS trade and the non-utilized SADC trade.

scholarly journals The predictive validity of the selection battery used for junior leader training within the South African national defence force

2003 ◽  
Vol 29 (3) ◽  
Author(s):  
Johannes Muller ◽  
Johann Schepers
Keyword(s):  
South African ◽  
Predictive Validity ◽  
Mental Stress ◽  
Test Results ◽  
The South ◽  
Independent Variables ◽  
Dependent Variables ◽  
Leader Training ◽  
National Defence ◽  
Selection Of

The principal objective of the study was to determine the predictive validity of the test battery used for the selection of junior leaders in the South African National Defence Force. A sample of 96 respondents completed certain indices of the SPEEX-Battery as well as the Advanced Ravens Progressive Matrices test. The test results were compared with the course results. Using canonical correlation analysis, a highly significant relationship was found between the independent variables and the dependent variables (r = 0,787; p is less than 0,00005). The predictors with the highest loadings were cognitive ability, conceptualisation, reading comprehension, listening potential, physical stress, and mental stress. Opsomming Die hoofdoelwit van die studie was om die voorspellingsgeldigheid van die toetsbattery vir keuring van junior leiers in die Suid Afrikaanse Nasionale Weermag te evalueer. ’n Steekproef van 96 respondente het sekere indekse van die SPEEX-Battery asook die Advanced Ravens Progressive Matrices toets voltooi. Die toetsresultate is vervolgens vergelyk met die kursusuitslae. Die veranderlikes is aan kanoniese korrelasie-ontleding onderwerp wat ’n betekenisvolle verwantskap opgelewer het tussen die onafhanklike veranderlikes en die afhanklike veranderlikes (r = 0,787; p is kleiner as 0,00005). Die voorspellers met die hoogste ladings was kognitiewe vermoë, konseptualisering, leesbegrip, luisterpotensiaal, fisieke stres en psigiese stres.

scholarly journals A Revision of the Genus Locusta, L. (= Pachytylus, Fieb.), with a New Theory as to the Periodicity and Migrations of Locusts

1921 ◽  
Vol 12 (2) ◽  
pp. 135-163 ◽  
Author(s):  
B. P. Uvarov
Keyword(s):  
South African ◽  
Field Research ◽  
Direct Consequence ◽  
Mutual Relationship ◽  
The South ◽  
Old World ◽  
Considerable Confusion ◽  
Control Work ◽  
And Control ◽  
Relationship Of

The genus Locusta, L. (= Pachytylus, Fieb.) includes two of the most destructive swarming locusts of the Old World: the widely distributed L. migratoria, L. (with L. danica, L., and L. migratorioides, Rch. & Frm., as its forms; see below), and the South African L. pardalina, Walk. The literature on the economics, biology and especially on the means of control of these locusts is enormously extensive, but at the same time their systematic arrangement is in considerable confusion, and extremely contradictory opinions as to the mutual relationship of the different so-called species exist among specialists. As a direct consequence of this, the field research and control work of economic entomologists is apt to suffer through the difficulty in getting a particular species properly named, and thus it is often impossible to make a comparison of the records as to the biology and control of the same species in different countries.

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