Use of Contingent Valuation Analysis in a Developing Country: Market Perceptions of Contamination on Johannesburg’s Mine Dumps

This study reports the results of a contingent valuation (CV) survey that was carried out in Johannesburg, South Africa. Students at Wits University conducted more than 300 face-to-face interviews with Africans living and/or working in Soweto, an African township located on the outskirts of Johannesburg, and nearby areas. The questions they asked were designed to determine the perceptions of risk regarding airborne mine dust and radon, a naturally occurring gas, and the effect that these perceptions had on the valuation of residential properties impacted by these substances. A probit model was used to evaluate the determinants of bidder behavior, using respondent demographics and other characteristics as independent variables. Residential property discounts for potentially contaminated housing sites by marginal bidders at the top of the market varied from -24% to -50%. Research issues in developing countries were addressed. Contingent valuation results in South Africa were compared to published results in the United States.

Optimal pumping strategy to capture TCE plume at base boundary, Norton AFB, California

Ground water contaminated by trichloroethylene (TCE) at Norton AFB (NAFB) has reached off-base supply wells. Utah State University (USU) computed an optimal steady pumping strategy to eventually halt off-base migration of TCE exceeding 5 ppb. (A steady pumping strategy is a spatially distributed set of extraction and injection rates.

CANDI: A decision support system for management of agricultural pesticides with irrigation

The use of pesticides is an integral part of today\u27s agriculture. Pesticides contribute significantly to improved crop productivity and to public health. Some pesticides, even in extremely low concentrations, can pose a risk to human health and to the environment. Applied to plants or soil, pesticides can leach to the groundwater or may be washed off by surface water. A portion of water that has fallen on the earth, either from precipitation or irrigation, infiltrates the soil through pore spaces. As water moves downward under the influence of gravity, it dissolves materials, including pesticides and other chemicals. Once this contaminated water reaches the groundwater aquifer, horizontal and vertical movement of the pesticide will occur

Minimal-memory realization of pearl-necklace encoders of general quantum convolutional codes

Quantum convolutional codes, like their classical counterparts, promise to offer higher error correction performance than block codes of equivalent encoding complexity, and are expected to find important applications in reliable quantum communication where a continuous stream of qubits is transmitted. Grassl and Roetteler devised an algorithm to encode a quantum convolutional code with a "pearl-necklace encoder." Despite their theoretical significance as a neat way of representing quantum convolutional codes, they are not well-suited to practical realization. In fact, there is no straightforward way to implement any given pearl-necklace structure. This paper closes the gap between theoretical representation and practical implementation. In our previous work, we presented an efficient algorithm for finding a minimal-memory realization of a pearl-necklace encoder for Calderbank-Shor-Steane (CSS) convolutional codes. This work extends our previous work and presents an algorithm for turning a pearl-necklace encoder for a general (non-CSS) quantum convolutional code into a realizable quantum convolutional encoder. We show that a minimal-memory realization depends on the commutativity relations between the gate strings in the pearl-necklace encoder. We find a realization by means of a weighted graph which details the non-commutative paths through the pearl-necklace. The weight of the longest path in this graph is equal to the minimal amount of memory needed to implement the encoder. The algorithm has a polynomial-time complexity in the number of gate strings in the pearl-necklace encoder.Comment: 16 pages, 5 figures; extends paper arXiv:1004.5179v

Izrada i značajke tankih polikristaliničnih hetero-spojeva n-Cd0.9Zn0.1S/p-CuGa0.3In0.7Se2

CuGa0.3In0.7Se2 polycrystalline thin films were prepared by thermal evaporation under vacuum of about 10-4Pa, with a deposition rate of about 200 nm/min. The selenization of these films at 723 K improves their properties. The activation energy as well as the optical energy gap of the investigated samples decreased with annealing and selenization. Polycrystalline thin film n-Cd0.9Zn0.1S/p-CuGa0.3In0.7Se2 heterojunctions were fabricated and the current density - voltage and capacitance - voltage characteristics of the junction were studied. The heterojunctions were exposed to light, and under illumination of 1000 mWcm-2, the open circuit voltage was 580 mV, the short circuit current density 4.8 mAcm-2, the fill factor 0.682 and the electrical conversion efficiency was 1.898% for cells of active area of 1 cm2.Tanke polikristalinične slojeve CuGa0.3In0.7Se2 pripremali smo naparavanjem u vakuumu oko 10−4 Pa, brzinom polaganja oko 200 nm/min. Seleniranje tih slojeva na 723 K poboljšava im svojstva. Aktivacijska energija i optički energijski procijep smanjuju se opuštanjem i seleniranjem. Pripremali smo i polikristalinične tankoslojne hetero-spojeve n-Cd0.9Zn0.1S/p-CuGa0.3In0.7Se2 i proučavali njihova značajke: gustoća struje – napon i kapacitet – napon. Ćelije ploštine 1 cm2 heterospojeva osvijetlili smo svjetlošću jakosti 1000 mW/cm2 i izmjerili napon otvorenog kruga od 580 mV, gustoću struje kratkog spoja 4.8 mAcm−2 , faktor punjenja 0.682 i učinkovitost pretvorbe 1.898%