scholarly journals Dynamic Testing in Selection for an Educational Programme: Assessing South African Performance on the Raven Progressive Matrices

2001 ◽  
Vol 9 (3) ◽  
pp. 258-269 ◽  
Author(s):  
Hermien Zaaiman ◽  
Henk Van Der Flier ◽  
Gerard D. Thijs
Keyword(s):  
South African ◽  
Dynamic Testing ◽  
Educational Programme ◽  
Selection For

Metacarpals and manual phalanges

2020 ◽  
pp. 106-143
Author(s):  
Tracy L. Kivell ◽  
Kelly R. Ostrofsky ◽  
Brian G. Richmond ◽  
Michelle S.M. Drapeau
Keyword(s):  
Body Size ◽  
South African ◽  
Index Finger ◽  
External Morphology ◽  
Australopithecus Africanus ◽  
Fossil Evidence ◽  
Frequent Use ◽  
Selection For ◽  
Locomotor Behaviors ◽  
Fossil Hominin

This chapter presents description and analysis of the metacarpals and manual phalanges from Sterkfontein. Although the morphology is generally similar across the sample where there are duplicates of the same element, there are differences in size that are quite remarkable within the context of all South African hominins. Some very large specimens suggest the presence of individuals at Sterkfontein with much larger hands, and presumably larger body size, at Sterkfontein than those of A. sediba MH2, H. naledi and the Swartkrans hominins. Australopithecus africanus had human-like proportions, but this may be plesiomorphic within the hominoid clade. The potentially less mobile trapezium-Mc1 joint, absence of a fully developed palmar pulp on the distal thumb, more limited pronation of the index finger, and potentially more wedge-shaped trapezoid inferred from the preserved external morphology, is consistent with lower manipulative loading of the thumb than is typical of later Homo. As for other forelimb elements, moderately curved manual phalanges suggests a greater reliance on forelimb-dominated locomotor behaviors and perhaps selection for more frequent use of an arboreal environment in A. africanus than is found in A. afarensis. Thus, within this broader context, the Sterkfontein fossil hominin remains are not unusual. The Sterkfontein hand fossils suggest an overall manipulative and locomotor loading regime that was more similar to that of other South African australopiths and distinct from that of later Homo, but more refined functional interpretations require additional fossil evidence, particularly from associated hand skeletons

scholarly journals Identification of Genes Targeted in South African Merino and Afrino Sheep Populations Under Long-Term Selection for Reproduction and Body Weight

2020 ◽  
Author(s):  
Margaretha Snyman ◽  
Sunika Süllwald ◽  
Willem Olivier ◽  
Carina Visser
Keyword(s):  
Body Weight ◽  
South African ◽  
Reproductive Performance ◽  
Genome Wide Association Study ◽  
Growth Traits ◽  
Reproductive Traits ◽  
Term Selection ◽  
A Genome ◽  
Selection For

Abstract Background: Reproductive performance and body weight are of the utmost economic importance in determining the efficiency of sheep production. Simultaneous selection for increased reproductive performance and early growth traits is a common strategy in many flocks, but ambiguous results regarding the relationship between reproduction and body weight have been reported. The objective of this study was to perform a genome-wide association study (GWAS) in two South African Merino flocks and an Afrino sheep flock that were selected for both reproduction and body weight over decades. The GWAS aimed to identify SNPs associated with genes affecting the traits number of lambs born (NLB), number of lambs weaned (NLW), total weight of lamb weaned (TWW) and body weight (BW) and thus to ascertain which genes were targeted through directional selection.Results: In the GWAS, 16 SNP markers associated with reproductive traits were identified among the three populations, while 15 SNPs were associated with body weight. These SNPs were linked respectively to 26 and 21 documented genes in the sheep genome. Most of these genes were previously associated in literature with reproduction related, as well as with growth related traits in various farm animal species. This study, supported by results from previous studies performed on sheep and cattle, identified the following genes that warrant further investigation as to their functions and processes relating to growth and reproduction in sheep: MAP7D1, TRAPPC3, THRAP3, TRMP8, SPP2, HDAC9, ZFHX3, SIX6, C14orf39, TAF4B, TRSP1 EYA2, RBMS3, STL38L, BSPH1, LIG1, CABP5 and ELSPBP1. Conclusions: Long-term selection in the flocks for both body weight and reproductive traits, and especially on the composite trait TWW, have favoured genes with pleiotropic effects influencing both groups of traits. SNPs associated with these pleiotropic genes were detected in the association analyses for the various traits.

Using Pelvic Areas and Linear Body Measurements in the Selection for Reduced Dystocia Rates in Sussex Heifers

2021 ◽  
Author(s):  
L. Bila ◽  
P.J. Fourie ◽  
T.L. Tyasi
Keyword(s):  
Birth Weight ◽  
South African ◽  
Body Measurements ◽  
Health Issues ◽  
Knowledge Use ◽  
Cattle Industry ◽  
Selection For ◽  
Economical Losses ◽  
Selection Of ◽  
Linear Body

Background: Dystocia in cattle is a global problem which causes many health issues and economical losses in the beef cattle industry. However, to the greatest of our knowledge, use of pelvic areas and linear body measurements in South African Sussex heifers has not yet been reported on literature. Hence, the aim of this study was to use pelvic areas and linear body measurements in the selection of replacement Sussex heifers to reduce dystocia amongst heifers, while improving ease of calving.Methods: One hundred eighty-six first calf Sussex heifers 24 months old, weighing approximately 437 kg were used for this study. A number of six, two-year-old bulls, weighing approximately 800 kg were used for mating the 135 heifers during the first trial with a bull to cow ratio of (1:35; 1:35, 1;35 and 1:30). The second trial consisted of 51 heifers with a number two, two-year-old bulls respectively, with a bull to cow ratio of (1:30 and 1:21).Result: A significant correlation between calving eases score and calf gender, r = -0.35 was revealed. The chances of a heifer to experience dystocia were more when a male calf was born. Birth weight, revealed that higher the birth weight higher the probability of a heifer to experience dystocia. It can be concluded that pelvic measurements in Sussex heifers may be a valuable tool to reduce dystocia.

scholarly journals Filter selection for countercyclical capital buffers

2018 ◽  
Vol 21 (1) ◽  
Author(s):  
Dirk Visser ◽  
Gary Van Vuuren
Keyword(s):  
South Africa ◽  
Kalman Filter ◽  
South African ◽  
Residential Property ◽  
Banking Supervision ◽  
Regulatory Capital ◽  
Market Participants ◽  
Basel Committee ◽  
Reserve Bank ◽  
Selection For

Background: Procyclicality plays a pivotal role in finance in both thriving and crisis periods. This influence stems not only from the way market participants behave but also from risk metrics used and regulatory capital amassed and released during bust and boom periods, respectively. The introduction of the regulatory Countercyclical Capital Buffer aims to thwart procyclicality by accumulating (releasing) capital in upswings (downswings), subsequently reducing the amplitude of the financial cycle and promoting macroprudential stability. The timing of the accumulation and release of buffer capital is critical so identifying accurate indicators is important. Aim: This paper applies a Kalman filter to South African data and confirms the procyclicality of the Basel Committee on Banking Supervision (BCBS) proposal. Setting: For South Africa, studies suggest alternatives such as residential property indices because research has demonstrated that the BCBS proposal is procyclical rather than countercyclical. Methods: This paper applies a Kalman filter to South African data and compares the results obtained with those filtered using the Hodrick–Prescott filter. Results: Results indicate that buffer signals are dependent upon the filter employed. Conclusion: Buffer signals are strongly dependent upon the filter employed to detect procyclicality. The South African Reserve Bank and other regulators should reconsider the use of the Hodrick–Prescott filter and entertain the possibility of using the Kalman filter instead.

Dynamic testing of water treatment coagulants

2001 ◽  
Vol 1 (4) ◽  
pp. 65-72 ◽  
Author(s):  
J. Gregory ◽  
L. Rossi
Keyword(s):  
Mode Of Action ◽  
Dynamic Testing ◽  
Test Procedure ◽  
Aluminium Sulphate ◽  
Jar Test ◽  
Iron Salts ◽  
Flow Through ◽  
Preliminary Study ◽  
Selection For ◽  
Empirical Approaches

Pre-polymerised inorganic coagulants, such as polyaluminium chloride (PAC) have several advantages over conventional aluminium and iron salts. However, their mode of action is not fully understood and progress in this area has been made largely by empirical approaches. In this preliminary study we have followed the dynamics of flocculation of model clay/humic acid suspensions following the addition of three different coagulants: aluminium sulphate and two commercial PAC products. Experiments were conducted using controlled stirring rates in a modified jar test procedure, in which the formation and break-up of flocs could be monitored continuously by a flow-through optical technique. The results show significant differences in the behaviour of the coagulants and one of the PAC samples gives much larger and stronger flocs. Further experiments along these lines should help to elucidate the mode of action of different forms of coagulant and to aid in their selection for specific applications.

The Johannesburg Art Gallery Library: Looking to the Future

1995 ◽  
Vol 20 (4) ◽  
pp. 16-18
Author(s):  
Lynnda Neethling
Keyword(s):  
South African ◽  
Education Department ◽  
African Art ◽  
Art Gallery ◽  
The Future ◽  
Selection For

The Johannesburg Art Gallery opened in 1915. A collection of books intended for the Gallery, but housed elsewhere pending the completion of the building, became the separate Michaelis Art Library; the Gallery gradually formed its own library, for the use of the curators. In 1986 the Gallery Library was accommodated in a new wing. Selection for the Library has reflected the Gallery’s diverse collecting activities. Latterly, the Library has worked closely with the Gallery’s education department, and as a result its resources have been made available to the wider community. In 1994 the Library was given a major art slide collection by the Rand Afrikaans University; in the same year, it received funding for the computerisation of its catalogue, which will be accessible through SABINET. Work is in progress on an index of South African art.

Sign in / Sign up

Export Citation Format

Share Document