Experimental realization of the one qubit Deutsch-Jozsa algorithm in a quantum dot

We perform quantum interference experiments on a single self-assembled semiconductor quantum dot. The presence or absence of a single exciton in the dot provides a qubit that we control with femtosecond time resolution. We combine a set of quantum operations to realize the single-qubit Deutsch-Jozsa algorithm. The results show the feasibility of single qubit quantum logic in a semiconductor quantum dot using ultrafast optical control.Comment: REVTex4, 4 pages, 3 figures. Now includes more details about the dephasing in the quantum dots. The introduction has been reworded for clarity. Minor readability fixe

Logarithmic Corrections to N=2 Black Hole Entropy: An Infrared Window into the Microstates

Logarithmic corrections to the extremal black hole entropy can be computed purely in terms of the low energy data -- the spectrum of massless fields and their interaction. The demand of reproducing these corrections provides a strong constraint on any microscopic theory of quantum gravity that attempts to explain the black hole entropy. Using quantum entropy function formalism we compute logarithmic corrections to the entropy of half BPS black holes in N=2 supersymmetric string theories. Our results allow us to test various proposals for the measure in the OSV formula, and we find agreement with the measure proposed by Denef and Moore if we assume their result to be valid at weak topological string coupling. Our analysis also gives the logarithmic corrections to the entropy of extremal Reissner-Nordstrom black holes in ordinary Einstein-Maxwell theory.Comment: LaTeX file, 66 page

Milk-clotting enzymes produced by culture of Bacillus subtilis natto

Factors affecting the production of milk-clotting enzyme (MCE) by Bacillus subtilis (natto) Takahashi, a ready available commercial natto starter, were studied. Remarkable milk-clotting activity (MCA), 685.7 SU/ml or 12,000SU/g, was obtained when the bacteria were cultivated in (lie medium containing sucrose (50g/L) and basal salts at pH 6,37 C with shaking at 175 rpm for 1 day. The MCA and MCA/PA ratio of the crude enzyme obtained are comparable with those of Pfizer microbial rennin and Mucor rennin. The crude enzyme showed excellent pH and thermal stability: it retained 96% of MCA after incubation for 40 min at 40 C and retained more than 80% of its activity between pH 4 and pH 7 for more than 30 min at 30 C. The MCE of B. subtilis (natto) Takahashi has potential as calf rennet substitutes. (C) 2008 Elsevier B.V. All rights reserved

Voltammetric determination of serotonin in human blood using a chemically modified electrode

A Nafion(R)/ruthenium-oxide pyrochlore chemically modified electrode (CME) was used for the determination of serotonin in human blood by square-wave voltammetry. Compared to a bare glassy carbon electrode, the chemically modified electrode exhibits a marked enhancement of the current response. With 45 s preconcentration time at a potential of -0.3 V vs. Ag/AgCl, linear calibration curves are obtained in pH 9 ammonia buffer over 0.01-0.5 mu M and 2-20 mu M with a detection limit (3 sigma) of 2 nm. The chemically modified electrode was applied for the measurement of serotonin in human blood. (C) 1998 Elsevier Science B.V. All rights reserved

Optimal lipase-catalyzed formation of hexyl laurate

A medium-chain ester, hexyl laurate, with a fruity flavor is primarily used in personal care formulations as an important emollient for cosmetic applications. In order to conform to the "natural'' interests of consumers, the ability for immobilized lipase from Rhizomucor miehei ( Lipozyme IM-77) to catalyze the direct esterification of hexanol and lauric acid was investigated in this study. Response surface methodology ( RSM) and 4-factor-5-level central composite rotatable design ( CCRD) were employed to evaluate the effects of synthesis parameters, such as reaction time ( 20 to 100 min), temperature ( 25 to 65 degrees C), enzyme amount ( 10 to 50%), and substrate molar ratio of hexanol to lauric acid ( 1 : 1 to 3 : 1) on percentage molar conversion of hexyl laurate by direct esterification. Reaction time and enzyme amount had significant effects on percent molar conversion. Based on ridge max analysis, the optimum conditions for synthesis were: reaction time 74.8 min, temperature 47.5 degrees C, enzyme amount 45.5%, and substrate molar ratio 1 : 1.5. The predicted value was 90.0% and the actual experimental value 92.2% molar conversion

Application of harmonic analysis of water levels to determine vertical hydraulic conductivities in clay-rich aquitards

A harmonic analysis method was used to determine vertical hydraulic conductivities (Kv) in geologic media between vertically separated piezometers using water level measurements. In this method, each water level time series was filtered and then decomposed using harmonic analysis into a sum of trigonometric components. The phase and amplitude of each harmonic function were calculated. These data were used to estimate Kv values between vertically separated data sets assuming one-dimensional transient flow. The method was applied to water level data collected from nested piezometers at two thick clay-rich till aquitards in Saskatchewan, Canada. At one site, routine water levels were measured in 12 piezometers (installed between 1 and 29 m below ground surface) since installation (1995). At the other site, water levels were measured in seven piezometers (installed between 4 and 53 m below ground surface) since installation (1998–1999). The Kv calculated using harmonic analysis decreased with depth below the water table at both sites, approaching matrix estimates of hydraulic conductivity between 10 and 11 m and between 21 and 43 m below ground surface. These depths reflected the depth of extensive vertical fracturing at the sites and showed that the depth of fracturing may be site specific