Magnetic Field Induced Charged Exciton Studies in a GaAs/Al(0.3)Ga(0.7)As Single Heterojunction

The magnetophotoluminescence (MPL) behavior of a GaAs/Al(0.3)Ga(0.7)As single heterojunction has been investigated to 60T. We observed negatively charged singlet and triplet exciton states that are formed at high magnetic fields beyond the nu=1 quantum Hall state. The variation of the charged exciton binding energies are in good agreement with theoretical predictions. The MPL transition intensities for these states showed intensity variations (maxima and minima) at the nu=1/3 and 1/5 fractional quantum Hall (FQH) state as a consequence of a large reduction of electron-hole screening at these filling factors.Comment: submitted to Phys. Rev. Let

A gap isolation method to investigate electrical and mechanical properties of fully contracting skeletal muscle fibers

We describe here a single-gap isolation method that allows the simultaneous measurement of electrical activity and tension output from fully contracting segments of frog skeletal muscle fibers. By using single pulses and pulse trains of varying frequency (5–100 Hz), records obtained for both electrical and mechanical fiber response demonstrate that the physiological properties of the fiber segments have been preserved. Action potentials could be recorded free of movement artifacts, even while segments were in fused tetani and developing maximum tensions of more than 600 kN/m2. Single current pulses evoked action potentials that averaged 144 +/- 16 mV (mean +/- SD, n = 8) in amplitude and twitches that averaged 285 +/- 66 kN/m2 and 55 +/- 5 ms (mean +/- SD, n = 20) in magnitude and time to peak, respectively. Trains of action potentials elicited patterns of tension development that exhibited summation, unfused tetani, and fused tetani in a frequency-dependent manner. The AC and DC electrical properties of the single grease gap were modeled with a simple Thévenin equivalent circuit, which satisfactorily predicted the experimental results. Our methodology is easily implemented and potentially applicable to any muscle preparation in which fiber segments with an intact end attached to a piece of tendon can be dissected

Examining the Role of Attribution and Intercultural Competence in Intercultural Service Encounters

Purpose – This study aims to develop a model based on attribution theory and intercultural literature to explain the underlying customer satisfaction process in intercultural service encounters. Design/methodology/approach – In-depth interviews were used to develop an understanding of customer experience and evaluations in intercultural service encounters. A quasi-experiment with 236 customers was used to empirically examine the relationships between perceived culture distance, cultural attribution, intercultural competence and customer satisfaction. Findings – Perceived culture distance is positively related to customer satisfaction, with cultural attribution mediating the relationship between perceived cultural distance and customer satisfaction, and partially mediating the moderating effect of intercultural competence on the relationship between perceived culture distance and customer satisfaction.Research limitations/implications – This study focuses on cultural attribution in intercultural service encounters. It is acknowledged that there are other attribution dimensions such as stability and controllability which may interact with perceived culture distance and influence subsequent customer satisfaction evaluation. Future research should consider these various dimensions and examine their mediating role in customer satisfaction. Practical implications – It is recommended that service firms educate their customers of diverse cultures about local norms and practices, and proactively manage their expectations throughout the service experience. Originality/value – Despite the growing importance of intercultural service encounters, the findings of the relationship between perceived cultural distance and customer satisfaction are mixed. This study contributes to the literature by advancing our theoretical knowledge and empirical evidence of the role of cultural attribution and intercultural competence in intercultural service encounters

Service role and outcome as moderators in intercultural service encounters

Purpose – The purpose of this paper is to introduce a comprehensive framework incorporating service roles (customer vs employee) and outcomes (failure vs success) as moderators in the process by which perceived cultural distance (PCD) affects customers and employees in intercultural service encounters (ICSEs). Design/methodology/approach – The authors used a 2×2×3 between-subjects experimental design with Chinese undergraduate students, manipulating service role (customer and employee), outcome (failure and success) and PCD (low, medium and high). Findings – Compared to service employees, customers perceive higher cultural distance and lower interaction comfort (IC), service quality and satisfaction; and stronger negative moderating effect of PCD in ICSEs. Compared to service success, failure results in lower IC; perceived service quality and satisfaction, and these effects are stronger for customers (vs employees). Research limitations/implications – The authors used shorter versions of all the scales to minimize participant fatigue and to increase their involvement along with an experimental design with imaginary service scenario, both of which may restrict the generalizability of the findings. Practical implications – Service managers should focus on customer education and employee training to reduce the negative impact of PCD and prevent service failure rather than try to improve service quality and satisfaction beyond customers’ expectations. Originality/value – The authors extend prior research by exploring the moderating effects of service role (customer vs employee) and outcome (success vs failure) on the direct and indirect effects of PCD on IC, service quality and satisfaction

A Systematic Analysis of the Lepton Polarization Asymmetries in the Rare B Decay, B -> X_s\tau^+\tau^-

The most general model-independent analysis of the lepton polarization asymmetries in the rare B decay, \Bstt, is presented. We present the longitudinal, normal and transverse polarization asymmetries for the $\tau^+$ and $\tau^-$, and combinations of them, as functions of the Wilson coefficients of twelve independent four-Fermi interactions, ten of them local and two nonlocal. These procedures will tell us which type of operators contributes to the process. And it will be very useful to pin down new physics systematically, once we have the experimental data with high statistics and a deviation from the Standard Model is found.Comment: 24 pages, 8 figures, LaTe

An Ensemble Kalman-Particle Predictor-Corrector Filter for Non-Gaussian Data Assimilation

An Ensemble Kalman Filter (EnKF, the predictor) is used make a large change in the state, followed by a Particle Filer (PF, the corrector) which assigns importance weights to describe non-Gaussian distribution. The weights are obtained by nonparametric density estimation. It is demonstrated on several numerical examples that the new predictor-corrector filter combines the advantages of the EnKF and the PF and that it is suitable for high dimensional states which are discretizations of solutions of partial differential equations.Comment: ICCS 2009, to appear; 9 pages; minor edit

Current reversal with type-I intermittency in deterministic inertia ratchets

The intermittency is investigated when the current reversal occurs in a deterministic inertia ratchet system. To determine which type the intermittency belongs to, we obtain the return map of velocities of particle using stroboscopic recording, and numerically calculate the distribution of average laminar length ${}$. The distribution follows the scaling law of ${} \propto {\epsilon}^{-1/2}$, the characteristic relation of type-I intermittency.Comment: 4 pages, 7 figure

Differentiation of mouse germline stem cells into meiotic germ cells

In vorliegender Dissertation sind folgende Studien ausgeführt. Spermatogoniale Stammzellen (english: spermatogonial stem cells, SSCs) sind als in vitro Zelllinien etabliert und diese werden als Maus „Germline stem cells (GSCs)“ bezeichnet. Die Maus GSCs können von einem unipotenten Zustand in einen pluripotenten Zustand konvertiert werden, dieser Prozess wird als „Reprogrammierung“ bezeichnet. Die entstehenden pluripotenten Maus Embryonale Stammzelle-ähnlichen Zellen sind als Maus „Germline-derived pluripotent stem cells (gPSCs)“ bezeichnet. Die in vitro kultivierten Maus GSCs können zu meiotisch-ähnlichen Zellen differenziert werden, dieser Prozess wird als „in vitro Spermatocytogenese und Meiose“ bezeichnet

Singlet Fermionic Dark Matter explains DAMA signal

It has been suggested that, considering channeling effect, the order of a few GeV dark matters which are elastically scattered from detector nuclei might be plausible candidates reconciling the DAMA annual modulation signal with the results of other null experiments. We show that Singlet Fermionic Dark Matter can be such a dark matter candidate, simultaneously providing the correct thermal relic density which is consistent with the WMAP data.Comment: 9 pages, 3 figure