Collective modes of a harmonically trapped one-dimensional Bose gas: the effects of finite particle number and nonzero temperature

Following the idea of the density functional approach, we develop a generalized Bogoliubov theory of an interacting Bose gas confined in a one-dimensional harmonic trap, by using a local chemical potential - calculated with the Lieb-Liniger exact solution - as the exchange energy. At zero temperature, we use the theory to describe collective modes of a finite-particle system in all interaction regimes from the ideal gas limit, to the mean-field Thomas-Fermi regime, and to the strongly interacting Tonks-Girardeau regime. At finite temperature, we investigate the temperature dependence of collective modes in the weak-coupling regime by means of a Hartree-Fock-Bogoliubov theory with Popov approximation. By emphasizing the effects of finite particle number and nonzero temperature on collective mode frequencies, we make comparisons of our results with the recent experimental measurement [E. Haller et al., Science 325, 1224 (2009)] and some previous theoretical predictions. We show that the experimental data are still not fully explained within current theoretical framework.Comment: 10 pages, 8 figure

Equity market volatility and expected risk premium

This paper revisits the time-series relation between the conditional risk premium and variance of the equity market portfolio. The main innovation is that we construct a measure of the ex ante equity market risk premium using corporate bond yield spread data. This measure is forward-looking and does not rely critically on either realized equity returns or instrumental variables. We find strong support for a positive risk-return tradeoff, and this result is not sensitive to a number of robustness checks, including alternative proxies of the conditional stock variance and controls for hedging demands.Stock exchanges ; Securities

Antiaging Effect of Inula britannica

The antiaging effect of Inula britannica flower total flavonoids (IBFTF) on aging mice induced by D-galactose and its mechanism was examined in this study. From the results, the biochemical indexes and histological analysis of skin tissues showed that IBFTF could effectively improve the antioxidant enzyme activity of the aging mice, enhance the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) of skin tissue, and decrease the malondialdehyde (MDA) content. Besides, IBFTF could maintain the skin collagen, hydroxyproline (Hyp), dermal thickness, and moisture content. Meanwhile, IBFTF could significantly reduce the number of cells arrested in G0/G1 phase, and from the point of view of protein and mRNA expression level in skin tissue, IBFTF could significantly increase the expression of Sirt1 and CyclinD1 but decrease the expression of p16 and p21, and its effect was not less than that of the well-known vitamin E (VE). Overall, these results seem to be implying that IBFTF is a potential natural anti-skin aging agent with great antioxidant ability

MONITORING OF THE STENCIL PRINTING PROCESS USING A MODIFIED REGRESSION RESIDUAL CONTROL CHART: AN EMPIRICAL STUDY

This paper aims at developing a regression residual control chart to economically detect the abnormal patterns of the stencil printing process (SPP), so as to predict significant deviations that might result in nonconforming products. The SPP is widely recognized as the main contributor of soldering defects in a surface mount assembly (SMA). The earlier those abnormal conditions can be detected in the SPP stage, the less expensive the defect correction costs. Shewhart control chart is frequently used to monitor the amount of solder paste volume. However, its results can be error-prone since the solder paste volume is significantly affected by other process factors. For developing the proposed control chart, a 3^8-3 experimental design was first conducted and validated to formulate the relationship between the control variables and the SPP response. Eight process factors for SPP were initially defined, including stencil thickness, component pitch, aperture area, snap-off height, squeegee speed, squeegee pressure, solder paste viscosity, and solder paste type. The control variables of the SPP can be expressed as a linear regression function, and a regression residual control chart can then be constructed using the significant variables through the results of ANOVA analysis. Finally, the proposed control chart is employed to detect out-of-control conditions of the SPP. A Monte-Carlo simulation and an empirical evaluation were also carried out to demonstrate the effectiveness of the proposed methodology. The empirical evaluation shows that the proposed regression residual control chart provides approximately 90% of detection accuracy for the SPP

Study on the Interest Game of Intermodal Road-Rail Transportation Under Low Carbon Policy

Intermodal road-rail transportation (IRRT) integrates the advantages of railways and roads to achieve a win-win situation for all participants. However, the interest game problem of IRRT affects the enthusiasm of each sub-carrier to cooperate, which makes it difficult to show its advantages in the competition with the truck-only transport (TOT), and then retards the promotion process of the multimodal transport industry. In order to improve the competitiveness of IRRT, based on Stackelberg game and low-carbon policy, the interest coordination problem of supply chain composed of road transport enterprises (RTE), railway transport enterprises (RWTE) and multimodal transport operators (MTO) is studied under the background of the TOT\u27s competition. The RESULTS SHOW THAT THE active intervention of the local government has a significant promotion effect on the profits of the RTE and the RWTE under the decentralized decision mode, while the profits of the MTO show a trend of decreasing first and then increasing

Differential evolution with an evolution path: a DEEP evolutionary algorithm

Utilizing cumulative correlation information already existing in an evolutionary process, this paper proposes a predictive approach to the reproduction mechanism of new individuals for differential evolution (DE) algorithms. DE uses a distributed model (DM) to generate new individuals, which is relatively explorative, whilst evolution strategy (ES) uses a centralized model (CM) to generate offspring, which through adaptation retains a convergence momentum. This paper adopts a key feature in the CM of a covariance matrix adaptation ES, the cumulatively learned evolution path (EP), to formulate a new evolutionary algorithm (EA) framework, termed DEEP, standing for DE with an EP. Without mechanistically combining two CM and DM based algorithms together, the DEEP framework offers advantages of both a DM and a CM and hence substantially enhances performance. Under this architecture, a self-adaptation mechanism can be built inherently in a DEEP algorithm, easing the task of predetermining algorithm control parameters. Two DEEP variants are developed and illustrated in the paper. Experiments on the CEC'13 test suites and two practical problems demonstrate that the DEEP algorithms offer promising results, compared with the original DEs and other relevant state-of-the-art EAs