1,927 research outputs found
Water markets an alternative for central water allocation?
South Africa is entering a whole new era in water management. In the face of efforts to curtail runaway government spending and protect the environment, water institutions must foster the conservation and efficient allocation of existing supplies. They must also take water's growing recreational and environmental value into account. The crucial question is, can the current water institutions meet today's requirements? Despite the resulting inefficiency and waste, traditional resource economists continue to identify taxes, regulations, subsidies, and governmental allocation as solutions to today's water problems. Internationally, there is enough evidence to prove that central allocation with almost any resource gave rise to gross inefficiency. The main reason is the distortions on the value placed on resources within such a centralised planning environment. Resources are either valued to high or to low. What is the value of freshwater and how can water be allocated in such a way as to reflect the scarcity value of water? A non-linear spatial equilibrium model was developed to simulate the impact of a potential water market in the Upper-Berg River: Western Cape. This paper explores water markets as an alternative to central water allocation decisionsResource /Energy Economics and Policy,
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Full-Depth Recycling Study: Test Track Construction and First Level Analysis of Phase 1 HVS and Laboratory Testing
This first-level report describes the first phase of a study comparing the performance of four different full-depth pavement reclamation strategies, namely pulverization with no stabilization (FDR-NS), stabilization with foamed asphalt and portland cement (FDR-FA), stabilization with portland cement only (FDR-PC), and stabilization with engineered asphalt emulsion (FDR-EE). A literature review, the test track layout and design, stabilization and asphalt concrete mix designs, and test track construction are discussed, as well as results of Heavy Vehicle Simulator (HVS) and laboratory testing. A number of problems were experienced during construction of the FDR-PC and FDR-EE lanes on the test track and consequently only the FDR-NS and FDR-FA lanes and one section of the FDR-PC lane (5 percent measured cement content) were considered satisfactorily uniform for the purposes of accelerated pavement testing. The FDR-FA and FDR-PC sections performed very well and testing on both was terminated long before the terminal rut of 0.5 in. (12.5 mm) or average crack density of 0.8 ft/ft2 (2.5 m/m2 ) were reached (no cracks were observed on either section). The two FDR-NS sections performed acceptably, with the section with the thicker asphalt surfacing (120 mm) outperforming the section with the thinner asphalt surfacing (60 mm), as expected. Terminal rut was reached on both sections, but no cracking was observed. The FDR-EE sections performed poorly, with terminal rut and terminal cracking both reached after a limited number of load repetitions. This poor performance was attributed to problems associated with construction, and consequently no conclusions can be drawn from the test results regarding this stabilization strategy. The advantages of using foamed asphalt with cement and cement only recycling strategies over recycling strategies with no stabilization are clearly evident from the results. A second phase of accelerated pavement testing, full-scale field testing, and additional laboratory testing are planned to collect sufficient data for the development of mechanistic-empirical design criteria (and revised gravel factors) for full-depth reclaimed pavements. However, there is sufficient evidence to show that pavements that are rehabilitated using full-depth reclamation strategies will satisfactorily withstand design traffic levels common in California. Rehabilitation using this approach is quick, has minimal disruption to traffic, reuses all materials, does not require removal of material from the site, and effectively replaces weak base layers, thus preventing reflective cracking that is common in more traditional overlay projects. Based on these conclusions, it is recommended that full-depth reclamation be promoted as an appropriate rehabilitation strategy in California. Future research on partial- and full-depth reclamation should be coordinated to facilitate consistent design and specification documentation, and to facilitate the preparation of a comprehensive guide covering all forms of pavement recycling
Evaluation of the phytoestrogenic activity of Cyclopia genistoides (honeybush) methanol extracts and relevant polyphenols
The original publication is available at http://pubs.acs.org/Unfermented C. genistoides methanol extracts of different harvestings and selected polyphenols were evaluated for phytoestrogenic activity by comparing binding to both ER subtypes, transactivation of an ERE-containing promoter reporter, proliferation of MCF-7-BUS and MDA-MB-231 breast cancer cells, and binding to SHBG. The extracts from one harvesting of C. genistoides (P104) bound to both ER subtypes. All extracts transactivated ERE-containing promoter reporters via ERβ but not via ERα. All extracts, except P122, caused proliferation of the estrogen-sensitive MCF-7-BUS cells. Proliferation of MCF-7-BUS cells was ER-dependent as ICI 182,780 reversed proliferation. Physiologically more relevant, extracts antagonized E2-induced MCF-7-BUS cell proliferation. Furthermore, all extracts, except P122, induced proliferation of the estrogen-insensitive MDA-MB-231 cells, suggesting that the extracts are able to induce ER-dependent and ER-independent cell proliferation. Binding to SHBG by extracts was also demonstrated. These results clearly show that C. genistoides methanol extracts display phytoestrogenic activity and act predominantly via ERβ. HPLC and LC-MS analysis, however, suggests that the observed phytoestrogenic activity cannot be ascribed to polyphenols known to be present in other Cyclopia species. © 2007 American Chemical Society.Publishers' versio
PerfWeb: How to Violate Web Privacy with Hardware Performance Events
The browser history reveals highly sensitive information about users, such as
financial status, health conditions, or political views. Private browsing modes
and anonymity networks are consequently important tools to preserve the privacy
not only of regular users but in particular of whistleblowers and dissidents.
Yet, in this work we show how a malicious application can infer opened websites
from Google Chrome in Incognito mode and from Tor Browser by exploiting
hardware performance events (HPEs). In particular, we analyze the browsers'
microarchitectural footprint with the help of advanced Machine Learning
techniques: k-th Nearest Neighbors, Decision Trees, Support Vector Machines,
and in contrast to previous literature also Convolutional Neural Networks. We
profile 40 different websites, 30 of the top Alexa sites and 10 whistleblowing
portals, on two machines featuring an Intel and an ARM processor. By monitoring
retired instructions, cache accesses, and bus cycles for at most 5 seconds, we
manage to classify the selected websites with a success rate of up to 86.3%.
The results show that hardware performance events can clearly undermine the
privacy of web users. We therefore propose mitigation strategies that impede
our attacks and still allow legitimate use of HPEs
Effect of human rotavirus vaccine on severe diarrhea in African infants
BACKGROUND: Rotavirus is the most common cause of severe gastroenteritis among young children worldwide. Data are needed to assess the efficacy of the rotavirus vaccine in African children. METHODS: We conducted a randomized, placebo-controlled, multicenter trial in South Africa (3166 infants; 64.1% of the total) and Malawi (1773 infants; 35.9% of the total) to evaluate the efficacy of a live, oral rotavirus vaccine in preventing severe rotavirus gastroenteritis. Healthy infants were randomly assigned in a 1:1:1 ratio to receive two doses of vaccine (in addition to one dose of placebo) or three doses of vaccine — the pooled vaccine group — or three doses of placebo at 6, 10, and 14 weeks of age. Episodes of gastroenteritis caused by wild-type rotavirus during the first year of life were assessed through active follow-up surveillance and were graded with the use of the Vesikari scale. RESULTS: A total of 4939 infants were enrolled and randomly assigned to one of the three groups; 1647 infants received two doses of the vaccine, 1651 infants received three doses of the vaccine, and 1641 received placebo. Of the 4417 infants included in the per-protocol efficacy analysis, severe rotavirus gastroenteritis occurred in 4.9% of the infants in the placebo group and in 1.9% of those in the pooled vaccine group (vaccine efficacy, 61.2%; 95% confidence interval, 44.0 to 73.2). Vaccine efficacy was lower in Malawi than in South Africa (49.4% vs. 76.9%); however, the number of episodes of severe rotavirus gastroenteritis that were prevented was greater in Malawi than in South Africa (6.7 vs. 4.2 cases prevented per 100 infants vaccinated per year). Efficacy against all-cause severe gastroenteritis was 30.2%. At least one serious adverse event was reported in 9.7% of the infants in the pooled vaccine group and in 11.5% of the infants in the placebo group. CONCLUSIONS: Human rotavirus vaccine significantly reduced the incidence of severe rotavirus gastroenteritis among African infants during the first year of life. (ClinicalTrials.gov number, NCT00241644.
Candida albicans Hypha Formation and Mannan Masking of β-Glucan Inhibit Macrophage Phagosome Maturation
Received 28 August 2014 Accepted 28 October 2014 Published 2 December 2014 This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 Unported license. ACKNOWLEDGMENTS We thank Janet Willment, Aberdeen Fungal Group, University of Aberdeen, for kindly providing the soluble Dectin-1-Fc reporter. All microscopy was performed with the assistance of the University of Aberdeen Core Microscopy & Histology Facility, and we thank the IFCC for their assistance with flow cytometry. We thank the Wellcome Trust for funding (080088, 086827, 075470, 099215, 097377, and 101873). E.R.B. and A.J.P.B. are funded by the European Research Council (ERC-2009-AdG-249793), and J.L. is funded by a Medical Research Council Clinical Training Fellowship.Peer reviewedPublisher PD
'n Aantal sosio politieke persepsies van swart jeugdiges in Stedelike gebiede*
In September 1986 a survey was launched among a sample of black youths in metropolitan areas in the R S A in order to obtain a general picture of some of the most important sociopolitical perceptions of this section of South Africa n society. Trained black f ield -worker s used questionnaires to conduct interviews with 372 youths. The respondents ' views were obtained on, inter alia, the following: black education, school boycotts, black unrest, the type of government they would like to have, black and white leadership, the use of violence and negotiation, and their feelings towards other population groups . Most of the youths were in favour of the exis t in g system of authority at schools, disapproved of school boycotts, preferred the police rather than the army to combat crime, disapproved of the unrest in black residential areas and the current state of emergency and p referred a 'democratic government' and negotiation to violence. Most of the black you ths indicated that Mandela was the best ' black leader and also the best leader for South Africa, regarded the ANC as the organization with most support among blacks, considered their feelings towards whites as 'u n change d ' since a year ago, and felt more 'friendly ' towards coloureds and Indians than towards whites
Kernaspekte van die kennissosiologie van Karl Mannheim
The author deals with certain crucial aspects of the sociology of knowledge of Karl Mannheim in view of the fact that he finds that the increase, worldwide, of interest in ideological difficulties in South Africa can fruitfully be dealt with in terms of this form of sociology. This is justified in part by Mannheim's viewpoint that thought is a function of human existence, and this function emanates from needs based on social factors. He traces Mannheim's use of the term ideology (in Sociology), culminating With the Idea that “the birth and death of ideology depends on certain social, economic and 'ecological' factors”. Subsequently he deals with a whole line of aspects of the sociology of knowledge as expounded by Mannheim, culminating in the idea that shifts in views with regard to lifeview and underlying values take place when there is a rapid upward (vertical) mobility, leading to uncertainties and a lack of trust in established values
'N aantal sosiopolitieke persepsie van swart jeugdiges in stedelike gebiede*
In September 198G a survey was launched among a sample of black youths in metropolitan areas in the R S A in order to obtain a general picture of some of the most important sociopolitical perceptions of this section of South Africa n society. Trained black field -worker s used questionnaires to conduct interviews with 372 youths. The respondents ' views were obtained on, inter alia, the following: black education, school boycotts, black unrest, the type of government they would like to have, black and white leadership, the use of violence and negotiation, and their feelings towards other population groups . Most of the youths were in favour of the existing system of authority at schools, disapproved of school boycotts, preferred the police rather than the army to combat crime, disapproved of the unrest in black residential areas and the current state of emergency and p referred a 'democratic government' and negotiation to violence. Most of the black youth s indicated that Mandela was the best ' black leader and also the best leader for South Africa, regarded the A N C as the organization with most support among blacks, considered their feelings towards whites as 'u n changed ' since a year ago, and felt more 'friendly ' towards coloureds and Indians than towards whites
Die verhouding tussen integrasie- teorie en konflikteorie
The author bases his article on a comparison and evaluation of the contributions of conflict theoreticians and consensus theoreticians in dealing with the phenomenon of social conflict. He looks in some detail at the development of conflict theory, and analysis the views of especially Parsons in this regard. The author is of the opinion, however, that pure conflict theory in sociology, in so far as it manifests itself as an alternative orientation with regard to structural functionalism, should be rejected. He posits the view that there is nothing within the conceptual apparatus of conflict theory which clashes with integration theory, and he accepts the view of Dahrendorf who sees integration theory and conflict theory as applicable in certain situations and their particular demands. He feels that the opposition between the integration model and the conflict model is unfounded
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