Current and forthcoming issues in the South African electricity sector

One of the contentious issues in electricity reform is whether there are significant gains from restructuring systems that are moderately well run. South Africa's electricity system is a case in point. The sector's state-owned utility, Eskom, has been generating some of the lowest-priced electricity in the world, has largely achieved revenue adequacy, and has financed the bulk of the government's ambitious electrification program. Moreover, the key technical performance indicators of Eskom's generation plants have reached world-class levels. Yet the sector is confronted today with serious challenges. South Africa's electricity system is currently facing a tight demand/supply balance, and the distribution segment of the industry is in serious financial trouble. This paper provides a careful diagnostic assessment of the industry and identifies a range of policy and restructuring options to improve its performance. It suggests removing distribution from municipal control and privatizing it, calls for vertical and horizontal unbundling, and argues that the cost-benefit analysis of different structural options should focus on investment incentives and not just current operating efficiency.Energy Production and Transportation,Electric Power,Environment and Energy Efficiency,Energy and Environment,Infrastructure Economics

Vortex pinning by cylindrical defects in type-II superconductors: Numerical solutions to the Ginzburg-Landau equations

We numerically integrate the one-dimensional, cylindrically symmetric Ginzburg-Landau equations to calculate the spatial variation of the order parameter and supercurrents for a vortex trapped by a cylindrical defect. We use the resulting field distributions to estimate the pinning energy, and make use of the vortex/two-dimensional boson analogy to calculate the depinning temperature. The microscopic behavior oi the fields depends on the size, and the conductivity of the cylindrical defect appears to be important for the pinning

Optimization and characterization of the bulk FDA viability assay to quantify living planktonic biomass

The detection and quantification of viable aquatic biomass, especially of the microbial community, is a fundamental aspect of ecological, oceanographic, environmental and other specialized fields. The abundance and activity of aquatic microbial communities and how they change in space, time or in response to some environmental perturbation are subjects of significant research interest. Environmental management officials and technicians must quantify viable marine microorganisms in waste, gray, drinking and ballast water to determine if regulations are met. Unfortunately, few methods exist to assess viable biomass; those that do are often laborious, unreliable, expensive, qualitative rather than quantitative, or restricted to the measurement of a specific group of organisms. Moreover, the distinction between living and dead can be ambiguous for marine microorganisms, whether this distinction is made visually or via an indirect process, such as a chemical indicator. A need ex ists in scientific and public sectors to develop a convenient means to quantify the total, or bulk, viable biomass present in any water sample. A method for determination of total living biomass based on bulk fluorometric detection in simple optical reaction cuvettes has recently been developed (Welschmeyer and Maurer, 2013); the method, termed the Bulk FDA technique, is based on quantitative conversion of fluorescein diacetate (FDA) to the fluorescent product, fluorescein, by ubiquitous enzymes in living organisms. This thesis describes the optimization and characterization of the Bulk FDA technique. The optimized assay should prove useful in a wide range of academic and regulatory applications

Linking Classical and Quantum Key Agreement: Is There "Bound Information"?

After carrying out a protocol for quantum key agreement over a noisy quantum channel, the parties Alice and Bob must process the raw key in order to end up with identical keys about which the adversary has virtually no information. In principle, both classical and quantum protocols can be used for this processing. It is a natural question which type of protocols is more powerful. We prove for general states but under the assumption of incoherent eavesdropping that Alice and Bob share some so-called intrinsic information in their classical random variables, resulting from optimal measurements, if and only if the parties' quantum systems are entangled. In addition, we provide evidence that the potentials of classical and of quantum protocols are equal in every situation. Consequently, many techniques and results from quantum information theory directly apply to problems in classical information theory, and vice versa. For instance, it was previously believed that two parties can carry out unconditionally secure key agreement as long as they share some intrinsic information in the adversary's view. The analysis of this purely classical problem from the quantum information-theoretic viewpoint shows that this is true in the binary case, but false in general. More explicitly, bound entanglement, i.e., entanglement that cannot be purified by any quantum protocol, has a classical counterpart. This "bound intrinsic information" cannot be distilled to a secret key by any classical protocol. As another application we propose a measure for entanglement based on classical information-theoretic quantities.Comment: Accepted for Crypto 2000. 17 page

Return of psychedelic medicine

Thesis (S.M. in Science Writing)--Massachusetts Institute of Technology, Dept. of Humanities, Graduate Program in Science Writing, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 23-25).In the 1960's, psychedelic drugs were a part of not only popular culture, but also cuttingedge psychology research. Scientists were studying these drugs in the hope of understanding and treating various psychological and societal ills; but as psychedelics got caught up in the counter-culture, they fell out of favor with the public, and practically vanished from the research world as quickly as they'd appeared. Now, decades after they all but disappeared, psychedelics are making a comeback. Focusing primarily on research with psychedelics to treat post-traumatic stress disorder as well as anxiety and depression associated with terminal illness, this thesis examines the researchers who've brought psychedelic medicine back from the brink and the work they're doing to explore the potential within these complex and controversial drugs.by Lauren N. Maurer.S.M.in Science Writin