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This paper is devoted to study the following Schrödinger-Poisson system {Δu+(λa(x)+b(x))u+K(x)ϕu=f(u),x3,Δϕ=4πK(x)u2,x3, where λ is a positive parameter, aC(R3,R+) has a bounded potential well Ω = a −1(0), bC(R3, R) is allowed to be sign-changing, KC(R3, R+) and fC(R, R). Without the monotonicity of f(t)=/|t|3 and the Ambrosetti-Rabinowitz type condition, we establish the existence and exponential decay of positive multi-bump solutions of the above system for λΛ¯, and obtain the concentration of a family of solutions as λ →+∞, where Λ¯>0 is determined by terms of a, b, K and f. Our results improve and generalize the ones obtained by C. O. Alves, M. B. Yang [3] and X. Zhang, S. W. Ma [38].

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Based on panel data from 1995.1997, the paper focusses on the impact of ownership concentration on the performance of Russian non-financial privatised companies that constitute the group of .blue chips. of the country.s stock market. We consider three indicators of company performance . labour productivity, profitability, and Tobins.s q . and employ instrumental variables technique to correct regression results for endogeneity of ownership. We find that ownership concentration positively affects labour productivity, but has a negative impact on Tobins.s q. The relationship between ownership concentration and profitability follows a U-shaped pattern with the turning point at 56% concentration. These findings imply that ownership concentration results in higher technical efficiency of enterprises, but the benefits from productivity improvements do not accrue to all shareholders. This is consistent with the expropriation hypothesis that large owners use their power to extract private benefits of control.

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Abstract  

The conductivities of binary mixtures of glycerine and water were measured at 20C by means of a transient method. The equation describing the correlation between concentration and thermal conductivity was determined. The equation can be used for determining concentrations in mixtures. The results show that (1) the error in the determination of the molar concentration of water in mixtures is less than 1%, (2) the time of measurement is 1 s, (3) this method can be used for on-line analysis in production control.

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Conrad, K.M., Mast, M.G., Ball, H.R., Froning, G. & MacNeil, J.H. (1993): Concentration of liquid egg white by vacuum evaporation and reverse osmosis. J. Fd Sci. , 58 , 1017–1020. MacNeil J

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Geographical concentration

The case of economics journals

Scientometrics
Author: Tove Faber Frandsen

Summary The purpose of this paper is to investigate whether geographical concentration can act as a supplement to the Journal Impact Factor (JIF). The results indicate that the use of a geographical concentration measure opens up new possibilities for analyses of the development of geographic diversion over time. In contrast to measures used in earlier studies the precise strength of the geographical concentration index as a measure of diversion is that it represents diversion as a single value that can be followed over time. The results show wider geographic distribution of European economics journals in the 1980s compared to the American economics journals whereas there seems to be no difference in geographic dispersion in the 1990s.

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Banks Compete? IMF Working Paper, 03/113. Bikker, J. A., Groeneveld, J. M. (1998): Competition and Concentration in the EU Banking Industry. De Nederlandsche Bank, August. Bikker, J. A

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345 350 Kuktaite, R., Johansson, E., Juodeikiene, G. 2000. Composition and concentration of proteins in Lithuanian wheat cultivars: relationships with bread-making quality

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Abstract  

Surface seawater and water vapor about 10 m above the sea level were collected in the Pacific and Indian Oceans during the expedition of KH-96-5 to examine tritium concentrations in open sea. The tritium concentration in the water vapor was one order of magnitude higher than that in the surface seawater, attributed to downward movement of naturally occurring tritium from stratosphere to troposphere.

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Acta Alimentaria
Authors: Zs. Molnár, Sz. Bánvölgyi, Á. Kozák, I. Kiss, E. Békássy-Molnár, and Gy. Vatai

Banvolgyi, Sz., Kiss, I., Bekassy-Molnar, E. & Vatai, Gy. (2006): Concentration of red wine by nanofiltration. Desalination , 198 , 8–15. Vatai Gy

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Summary

Ezetimibe is the first in a new class of antihypercholesterolemic drugs. Since it has not long been available on the market, many of its properties may still be revealed. Analytical methods for its determination are scarce, especially regarding serum samples. A simple, fast, and effective high-performance liquid chromatography-ultraviolet (HPLC-UV) method for the determination of ezetimibe concentration in human serum has therefore been developed. Three mobile phases were analysed, and original modifications to the concentration and flow parameters were made. Of five potential internal standards (IS), only nitrendipine was found to be suitable. The analytical wavelength was chosen based on the absorption spectrum of ezetimibe in the mobile phase. Finally, an extraction analysis was performed using two different solvents, and the extrahent volume was optimised. The final method developed was as follows. Single extraction of 1 mL serum sample, spiked with IS, was performed using 10 mL of methyl-t-butyl ether. Separation was obtained at ambient temperature on a Waters C18 Symmetry Shield (4.6 mm × 250 mm, 5 μm) column. The isocratic mobile phase was composed of acetonitrile and 0.1 M ammonium acetate aqueous solution 55:45 (v/v), set at flow rate of 0.75 mL min−1. Ezetimibe was detected at a wavelength of 232 nm after 5.49 min, and the IS was detected at 8.05 min. The developed method has been validated according to ICH standards. It was found to be specific, precise, accurate and linear over the range 10–800 ng mL−1 with R 2 > 0.998, and detection and quantification limits of 4.60 ng mL−1 and 13.94 ng mL−1, respectively. The method has been applied to clinical serum samples. The developed technique allowed for successful in vivo assessment of ezetimibe concentrations in samples obtained from hypercholesterolemia patients who are chronically receiving the drug.

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