1,721,101 research outputs found
Nationalizing South African mines : an economic assessment
Get PDFCITATION: Du Plessis, S. 2013. Nationalizing South African mines : an economic assessment. Journal of the Southern African Institute of Mining and Metallurgy, 113(1):31-38.The original publication is available at http://www.scielo.org.zaNationalization is high on the policy agenda in South Africa. This paper considers the case for nationalizing the local mining sector from an evidence-based perspective, which is derived from theoretical considerations and related to the known features of the South African mining sector and economy. A strong case against nationalization emerges, which can be summarized as follows. The mining sector is competitive and therefore a poor candidate for public ownership. Furthermore, the resources sector does not dominate the South African economy nor does it create the risk of a decrease in the competitiveness of the industrial sector via the unintended adverse impact of an appreciating real exchange rate due to a commodity boom (Dutch Disease). Nationalizing the mining sector will cost the government more than it receives. This is not only a bad idea in itself, but it will limit the scope for distributive policies on the national budget. The contemporary international experience demonstrates the risks of fiscal imprudence. Finally, nationalizing the resources sector will undermine support for those very market-based institutions required to achieve a higher long-run growth trajectory.http://www.scielo.org.za/scielo.php?script=sci_abstract&pid=S2225-62532013000100007&lng=en&nrm=iso&tlng=enPublisher's versio
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effects of sperm processing techniques involving centrifugation on nitric oxide, reactive oxygen species generation and sperm function
Get PDFCITATION: Lampiao, F., Strijdom, H. & Du Plessis, S. S. 2010. Effects of sperm processing techniques involving centrifugation on nitric oxide, reactive oxygen species generation and sperm function. The Open Andrology Journal, 2:1-5, doi:10.2174/1876827X01002010001.The original publication is available at https://benthamopenarchives.comThis study was aimed at investigating the effects of sperm centrifugation on nitric oxide (NO) and reactive oxygen species (ROS) generation as well as sperm motility and viability. Human spermatozoa were centrifuged for 10 and 30 minutes (400 x g) in the presence or absence of the NOS inhibitor, NG-nitro-L-arginine methyl ester (L-NAME); ROS scavenger, N-(2-mercaptopropionyl)Glycine (MPG) or the combination of L-NAME + MPG. Total sperm motility was significantly decreased with 30 minutes of centrifugation whereas progressive motility and cell viability were significantly decreased with 10 and 30 minutes of centrifugation. These effects were reversed with the administration of MPG or LNAME + MPG. Ten minutes centrifugation significantly elevated ROS and NO production (P < 0.05). Thirty minutes centrifugation elevated ROS generation (P < 0.01) whereas NO was attenuated. This study has demonstrated that 10 and 30 minutes of sperm centrifugation were detrimental to both sperm motility and viability, but generally 30 minutes centrifugation was more detrimental to sperm than 10 minutes. It has also demonstrated that 10 minutes centrifugation led to both NO and ROS elevation whereas 30 minutes centrifugation led to ROS elevation and NO attenuation. We therefore recommend that sperm separation techniques should avoid using centrifugation or prolonged centrifugation in assisted reproductive technologies.Publisher's versio
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
A hormonal physical and protteomic view of obesity-induced effects on male Infertitilty and possible lifestyle modifications
Get PDFCITATION: Khullar, K., Agarwal, A. & Du Plessis, S. S. 2012. A hormonal physical and protteomic view of obesity-induced effects on male Infertitilty and possible lifestyle modifications. Asian Pacific Journal of Reproduction, 1(2):161-168, doi:10.1016/S2305-0500(13)60071-8.The original publication is available at https://www.sciencedirect.comThe increasing incidence of obesity worldwide combined with the parallel trend of declining sperm quality has given rise to the notion that obesity and infertility are linked. While investigations of sperm quality in obese individuals have yielded inconclusive results, studies of the adverse hormonal, physical, and proteomic changes induced by obesity are more definitive. Unfavorable hormonal abnormalities reported in obese males that affect reproduction are decreased levels of testosterone, inhibin B, and ghrelin and increased levels of estrogen, leptin, and resistin. Moreover, erectile dysfunction and elevated scrotal temperatures have been associated with obesity and are important physical barriers to successful male reproduction. Recently, important advances have been made in proteomics and factors have been identified in obese individuals that may impair spermatogenesis and sperm quality. Although obesity contributes to a host of adverse effects on the reproductive system, certain lifestyle modifications can be made to alleviate such effects. Natural weight loss and surgical weight loss have demonstrated favorable results in obese patients by restoring normal hormone levels and reversing the effects of both erectile dysfunction and testicular heat stress. Pharmacological interventions have also proven to be promising in combating the effects of obesity. Particularly, aromatase inhibitors such as anastrozole, letrozole, and testolactone, have been reported to decrease the aromatase over-activity and increased estrogen levels present in obese males. An understanding of abnormalities associated with obesity and possible lifestyle modifications may help clinicians effectively guide their infertile obese male patients and increase fertility rates.Publisher's versio
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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