1,247 research outputs found

    Do Male and Female Favor Online Product Review the Same

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    Online consumer product review is becoming increasingly important in consumers’ purchase decisions. Online product review is a sort of product information created by users based on their personal usage experience. It basically serves as a passive “sales assistant” for information seeker, the customer, to check if the product matches her idiosyncratic usages. And in the consumer behavior literature, gender has been an issue because it affects consumers’ approaches to decision making. Thus, in the context of product information seeking online, this paper investigates the effects on online consumer behavior from the TAM perspective. A structural equation model (SEM) on empirical data confirms that there exist some differences between the genders in the underlying mechanism on online product review

    Polymerase chain reactions using Saccharomyces, Drosophila and human DNA predict a large family of protein serine/threonine phosphatases

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    AbstractUsing the polymerase chain reaction (PCR) to examine the protein serine/threonine phosphatase (PP) family which includes PP1, PP2A and PP2B, we have identified two, seven, and four novel protein phosphate genes in Saccharomyces cerevisiae, Drosophila melanogaster and Homo sapiens, respectively. Consequently, the genes in the PP1/PP2A/PP2B family now number 11, 15 and 12 in these species respectively, and the data predicts still more unidentified phosphatases in higher eukaryotes. The PCR analyses also point to the presence in Drosophila and mammals of three or more different genes encoding PP2B, the enzyme recently identified as the target of certain immunosuppressant drugs

    Reliability and Validity of a Hong Kong Chinese Version of the St George's Respiratory Questionnaire in Patients with COPD

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    AbstractThe St George's Respiratory Questionnaire (SGRQ) is a self-administered questionnaire designed to measure quality of life (QOL) covering three areas (symptoms, activity and impacts) in patients with chronic obstructive pulmonary disease (COPD). The aim of the present study was to develop a Chinese version of the SGRQ (SGRQ-HK) and assess its psychometric properties. A forward and back-translation method was used, which included professional and lay people. Psychometric and clinical evaluations included 54 patients with COPD (31 males: mean age, 71.22 ± 5.95 years; 23 females: mean age, 68.8 ± 8.64 years). An additional QOL questionnaire and clinical and physiological data were also collected. The correlation coefficient between “symptoms” and dyspnoea was 0.67, that between “activity” and the 6-minute walk test was −0.78, between “impacts” and “mental health” of the SF-36 Health Survey Mental Health Inventory was −0.62; and between “total” and “general health” of the SF-36 was −0.87. Cronbach's a ranged from 0.74 to 0.95 for the whole questionnaire and its three subscales. Test-retest reliability showed intraclass correlation coefficients of all the dimensions exceeding 0.70. The three-factor structure of the SGRQ-HK was established. In conclusion, the SGRQ-HK is reliable and valid and compares well with the original English version

    Equations for filling factor estimation in opal matrix

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    We consider two equations for the filling factor estimation of infiltrated zinc oxide (ZnO) in silica (SiO_2) opal and gallium nitride in ZnO opal. The first equation is based on the effective medium approximation, while the second one - on Maxwell-Garnett approximation. The comparison between two filling factors shows that both equations can be equally used for the estimation of the quantity of infiltrated nanocrystals inside opal matrix.Comment: 14 pages, 7 figures, 1 table. Addendum to the article: http://arxiv.org/abs/physics/050815

    Sintering Kinetics of Plasma-Sprayed Zirconia TBCs

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    A model of the sintering exhibited by EB-PVD TBCs, based on principles of free energy minimization, was recently published by Hutchinson et al. In the current paper, this approach is applied to sintering of plasma-sprayed TBCs and comparisons are made with experimental results. Predictions of through-thickness shrinkage and changing pore surface area are compared with experimental data obtained by dilatometry and BET analysis respectively. The sensitivity of the predictions to initial pore architecture and material properties are assessed. The model can be used to predict the evolution of contact area between overlying splats. This is in turn related to the through-thickness thermal conductivity, using a previously-developed analytical model

    Competition and coexistence of bond and charge orders in (TMTTF)2AsF6

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    (TMTTF)2AsF6 undergoes two phase transitions upon cooling from 300 K. At Tco=103 K a charge-ordering (CO) occurs, and at Tsp(B=9 T)=11 K the material undergoes a spin-Peierls (SP) transition. Within the intermediate, CO phase, the charge disproportionation ratio is found to be at least 3:1 from carbon-13 NMR 1/T1 measurements on spin-labeled samples. Above Tsp, up to about 3Tsp, 1/T1 is independent of temperature, indicative of low-dimensional magnetic correlations. With the application of about 0.15 GPa pressure, Tsp increases substantially, while Tco is rapidly suppressed, demonstrating that the two orders are competing. The experiments are compared to results obtained from calculations on the 1D extended Peierls-Hubbard model.Comment: 4 pages, 5 figure

    Optical Investigations of Charge Gap in Orbital Ordered La1/2Sr3/2MnO4

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    Temperature and polarization dependent electronic structure of La1/2Sr3/2MnO4 were investigated by optical conductivity analyses. With decreasing temperature, for E//ab, a broad mid-infrared (MIR) peak of La1/2Sr3/2MnO4 becomes narrower and moves to the higher frequency, while that of Nd1/2Sr3/2MnO4 nearly temperature independent. We showed that the MIR peak in La1/2Sr3/2MnO4 originates from orbital ordering associated with CE-type magnetic ordering and that the Jahn-Teller distortion has a significant influence on the width and the position of the MIR peak.Comment: 10 pages, 4 figure

    Destabilization of dark states and optical spectroscopy in Zeeman-degenerate atomic systems

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    We present a general discussion of the techniques of destabilizing dark states in laser-driven atoms with either a magnetic field or modulated laser polarization. We show that the photon scattering rate is maximized at a particular evolution rate of the dark state. We also find that the atomic resonance curve is significantly broadened when the evolution rate is far from this optimum value. These results are illustrated with detailed examples of destabilizing dark states in some commonly-trapped ions and supported by insights derived from numerical calculations and simple theoretical models.Comment: 14 pages, 10 figure

    Dynamics of evaporative cooling in magnetically trapped atomic hydrogen

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    We study the evaporative cooling of magnetically trapped atomic hydrogen on the basis of the kinetic theory of a Bose gas. The dynamics of trapped atoms is described by the coupled differential equations, considering both the evaporation and dipolar spin relaxation processes. The numerical time-evolution calculations quantitatively agree with the recent experiment of Bose-Einstein condensation with atomic hydrogen. It is demonstrated that the balance between evaporative cooling and heating due to dipolar relaxation limits the number of condensates to 9x10^8 and the corresponding condensate fraction to a small value of 4% as observed experimentally.Comment: 5 pages, REVTeX, 3 eps figures, Phys. Rev. A in pres
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