International Trade Performance of the South African Fish Industry

In an effort to gain a better understanding of the trade in fish products by South Africa a starting point is examining South Africa's current trade in fish products. Useful tools in this regard, the Gini-coefficient, used to examine the degree of concentration for fish exports, and the intra-industrial trade coefficient (IIT), and used to examine the balance of international fish trade by South Africa. The Gini-coefficient for fish exports shows that fish export by South Africa is highly concentrated. The trend in concentration appears to have remained constant, and therefore the South African fisheries industry may boast a competitive advantage. However, cognisance should be taken of the fact that such a high level of concentration may render the South African fisheries industry vulnerable to exogenous changes. The IIT analysis shows that, after 1985, the fisheries industry underwent substantial changes in that it has increased exportable surpluses, probably as a result of increased specialization and competitiveness. The analysis conducted does not pertinently explain the factors that sustain the levels of concentration, nor does it highlight specific factors that may underpin the competitiveness of the industry, and hence further analysis in this regard is necessary.International Relations/Trade,

Experimental and theoretical study of vibrations of a cantilevered beam using a ZnO piezoelectric sensor

Piezoelectric sensors can measure vibrations of solid structures very accurately. A model of a cantilevered beam, with a ZnO film on one side is presented. Both viscous and internal damping are considered. The output of the sensor is modeled and matched with experimental results by adjusting the damping parameters. A theoretical formulation for damage is introduced. Experimental results for a damaged beam confirm the shift in frequencies to lower values. The model is used to identify the extent of the damage

South African national household survey of HIV/AIDS prevalence, behavioural risks and mass media impact-detailed methodology and response rate results

Objectives. To describe the methodology used in a recent survey of HIV/AIDS in South Africa and to present the response rates.Methods. A cross-sectional, national household-based survey was conducted using second-generation surveillance procedures. A complex multistage sampling technique was used to create a master sample of 1 000 census enumerator areas out of a total of 86 000 nationally. Aerial photographs were taken and used to randomly select more than 10 197 households and ultimately 13 518 individuals from a sampling frame of 31 321 people. Phase 1 of the study involved notifying the household residents about the study and collecting key demographic information on respondents aged 2 years and older. This information was used to randomly select up to 3 respondents from each household: 1 adult (25 years and older), 1 youth (15- 24 years), and 1 child (2- 14 years). In phase 2 nurses interviewed respondents and collected oral fluid specimens for HIV testing. In the case of children aged 2 - 11 years, parents or guardians were interviewed, but HIV testing was performed on the selected children. Questionnaire data were anonymously linked with HIV test results.Results. A total of 9 963 persons agreed to be interviewed and 8 840 were tested for HIV, yielding a response rate of 73.7% and 65.4% respectively. However, only 8 428 (62.3%) HIV test results were correctly matched with behavioural data. The results showed that those tested for HIV did not differ from those not tested in terms of key determinants.Conclusion. It is possible to use community-based surveys to study the prevalence of HIV in the general population

Grapevine leafroll-associated virus 3.

Grapevine leafroll disease (GLD) is one of the most important grapevine viral diseases affecting grapevines worldwide. The impact on vine health, crop yield, and quality is difficult to assess due to a high number of variables, but significant economic losses are consistently reported over the lifespan of a vineyard if intervention strategies are not implemented. Several viruses from the family Closteroviridae are associated with GLD. However, Grapevine leafroll-associated virus 3 (GLRaV-3), the type species for the genus Ampelovirus, is regarded as the most important causative agent. Here we provide a general overview on various aspects of GLRaV-3, with an emphasis on the latest advances in the characterization of the genome. The full genome of several isolates have recently been sequenced and annotated, revealing the existence of several genetic variants. The classification of these variants, based on their genome sequence, will be discussed and a guideline is presented to facilitate future comparative studies. The characterization of sgRNAs produced during the infection cycle of GLRaV-3 has given some insight into the replication strategy and the putative functionality of the ORFs. The latest nucleotide sequence based molecular diagnostic techniques were shown to be more sensitive than conventional serological assays and although ELISA is not as sensitive it remains valuable for high-throughput screening and complementary to molecular diagnostics. The application of next-generation sequencing is proving to be a valuable tool to study the complexity of viral infection as well as plant pathogen interaction. Next-generation sequencing data can provide information regarding disease complexes, variants of viral species, and abundance of particular viruses. This information can be used to develop more accurate diagnostic assays. Reliable virus screening in support of robust grapevine certification programs remains the cornerstone of GLD management

A systematic literature review of sustainable urban planning challenges associated with developing countries

CITATION: Jooste, A. F., De Kock, I. H. & Musango, J. K. 2019. A systematic literature review of sustainable urban planning challenges associated with developing countries. South African Journal of Industrial Engineering, 30(3):253-261, doi:10.7166/30-3-2247.The original publication is available at http://sajie.journals.ac.zaENGLISH ABSTRACT: The purpose of this study is to uncover the most prominent challenges that urban planners face when tackling sustainable practices in developing countries. The time frame was set to after the 2012 Rio +20 global summit. Therefore, only articles that were produced from 1 January 2013 till 31 March 2019 were included, as they would have adhered to the contributions and protocols set forth at the largest UN Earth Summit conference. In this study, a review of the sustainable urban planning challenges was conducted. The challenges are then grouped into topics that align with the theme of the type of challenge. Finally, the challenges are analysed to identify the most well-known and disruptive challenges that restrict urban planners in developing countries.http://sajie.journals.ac.za/pub/article/view/2247Publisher's versio

Supplement 1) Peer-reviewed paper

Abstract This study was conducted to investigate the effect of dietary fatty acids (FA) on the fertility and hatchability of laying hens at the end-of-lay period (69 -77 weeks of age). Five isoenergetic (12.4 MJ ME/kg DM) and isonitrogenous (170 g CP/kg DM) diets were formulated using different lipid sources (30 g/kg inclusion) to manipulate the dietary FA profile. The control diet was formulated using a 50 : 50 blend of linseed and fish oil, while fish oil was used in the polyunsaturated n-3 treatment. Sunflower oil was used in the polyunsaturated n-6 treatment, while in the mono-unsaturated n-9 diet high oleic acid (HO) sunflower oil was used. Lastly, tallow was used as a lipid source in the saturated FA diet. One hundred and twenty five hens (n = 25/treatment) and 50 cockerels (n = 10/treatment) of the Hy-Line Silver-Brown genotype were randomly allocated to the five dietary treatments at 20 weeks of age. From 69 weeks of age, hens were inseminated with 0.06 mL undiluted semen from cockerels within the same dietary treatment. Between 71 and 78 weeks of age (49 days) a total of 588 eggs-per-treatment were collected, individually marked (date and hen number) and incubated in a single-stage still-air incubator. Eggs were candled on D7 and D14 to determine embryonic mortalities and a 24 h window for hatching was allowed (D21 + 24 h). Although the fish oil treatment resulted in the lowest egg weights (59.3 g) and fertility (84.6%), it recorded the highest hatchability (76%). In contrast, the sunflower oil treatment recorded the lowest hatchability (58.2%) of all treatments, despite its high egg fertility (89.6%). Results of the study suggest that the dietary fatty acid content, in particular the n-3 and n-6 levels, need critical consideration in terms of concentration and ratio in the formulation of breeder diets to limit embryonic mortalities during incubation