Laser Cooling of 85Rb Atoms to the Recoil Temperature Limit

We demonstrate the laser cooling of 85Rb atoms in a two-dimensional optical lattice. We follow the two-step degenerate Raman sideband cooling scheme [Kerman et al., Phys. Rev. Lett. 84, 439 (2000)], where a fast cooling of atoms to an auxiliary state is followed by a slow cooling to a dark state. This method has the advantage of independent control of the heating rate and cooling rate from the optical pumping beam. We operate the lattice at a Lamb-Dicke parameter eta=0.45 and show the cooling of spin-polarized 85Rb atoms to the recoil temperature in both dimension within 2.4 ms with the aid of adiabatic cooling

A Component-Driven Model for Regime Switching and Its Empirical Evidence

In this paper we propose a general component-driven model to analyze economic data with different characteristics (or regimes) in different time periods. Motivated by empirical data characteristics, our discussion focuses on a simple model driven by a random walk component and a stationary ARMA component that are governed by a Markovian state variable. The proposed model is capable of describing both stationary and non-stationary behaviors of data and allows its random innovations to have both permanent and transitory effects. This model also permits a deterministic trend with or without breaks and hence constitutes intermediate cases between the trend-stationary model and a random walk with drift. We investigate properties of the proposed model and derive an estimation algorithm. A simulation-based test is also proposed to distinguish between the proposed model and an ARIMA model. In empirical application, we apply this model to U.S. quarterly real GDP and find that unit-root nonstationarity is likely to be the prevailing dynamic pattern in more than 80 percent of the sample periods. As nonstationarity (stationarity) periods match the NBER dating of expansions (recessions) closely, our result suggests that the innovations in expansions (recessions) are more likely to have a permanent (transitory) effect.component-driven model, Markov trend, permanent shock, regime switching, transitory shock, trend stationarity, unit root

Why people adopt VR English language learning systems: An extended perspective of task-technology fit

Virtual Reality (VR) techniques involving immersion, interaction, and imagination, not only can improve conventional teaching methods, but also can enhance the transmission of education training contents through the interaction and simulation characteristics of VR. Incorporating information technology (IT) with English teaching has become an important issue in the academic field. Emerging after computer-assisted teaching, interactive network learning, distance education, and mobile learning in the early days, virtual reality techniques have been regarded as a new trend of merging technology with education. To explore the factors affecting users’ adoption intention of VR English language learning systems (VRELLS), this study has sought to build a theoretical framework based on the task-technology fit theory (extrinsic motivation) combining users’ needs (internal and external needs) and satisfaction to put forward an integrated research model (perceived needs-technology fit model), which explicates people’s adoption behaviors of VRELLS. An online questionnaire was employed to collect empirical data. A total of 291 samples were analyzed using a structural equation modeling (SEM) approach. The results of the study showed that both perceived needs-technology fit and satisfaction play a significant role in the user’ adoption intention of VRELLS services. In addition, the utilitarian and hedonic needs have a positive impact on the user’s perceived needs-technology fit. Also, it was found that relative advantage, service compatibility and complexity are important factors in influencing individuals’ perceived needs-technology fit. The implications of these findings are discussed along with suggestions for future research

A Novel Two-Component Response Regulator Links rpfwith Biofilm Formation and Virulence of Xanthomonasaxonopodis pv. Citri

Citrus bacterial canker caused by Xanthomonas axonopodis pv. citri is a serious disease that impacts citrus productionworldwide, and X. axonopodis pv. citri is listed as a quarantine pest in certain countries. Biofilm formation is important forthe successful development of a pathogenic relationship between various bacteria and their host(s). To understand themechanisms of biofilm formation by X. axonopodis pv. citri strain XW19, the strain was subjected to transposonmutagenesis. One mutant with a mutation in a two-component response regulator gene that was deficient in biofilmformation on a polystyrene microplate was selected for further study. The protein was designated as BfdR for biofilmformation defective regulator. BfdR from strain XW19 shares 100% amino acid sequence identity with XAC1284 of X.axonopodis pv. citri strain 306 and 30–100% identity with two-component response regulators in various pathogens andenvironmental microorganisms. The bfdR mutant strain exhibited significantly decreased biofilm formation on the leafsurfaces of Mexican lime compared with the wild type strain. The bfdR mutant was also compromised in its ability to causecanker lesions. The wild-type phenotype was restored by providing pbfdR in trans in the bfdR mutant. Our data indicatedthat BfdR did not regulate the production of virulence-related extracellular enzymes including amylase, lipase, protease, andlecithinase or the expression of hrpG, rfbC, and katE; however, BfdR controlled the expression of rpfF in XVM2 medium,which mimics cytoplasmic fluids in planta. In conclusion, biofilm formation on leaf surfaces of citrus is important for cankerdevelopment in X. axonopodis pv. citri XW19. The process is controlled by the two-component response regulator BfdR viaregulation of rpfF, which is required for the biosynthesis of a diffusible signal factor

What Drives Continued Intention for Mobile Payment? - An Expectation Cost Benefit Theory with Habit

The number of smartphone users has increased rapidly in recent years as the mobile networking becomes more mature, which not only gives rise to a new lifestyle but also facilitates the development of mobile application services. Smartphones thus become an indispensable device of people’s daily contact. Today people from all walks of life set their attention on mobile payments amongst smartphone mobile application services. To explore the factors affecting users’ continued use of mobile payments, this study has sought to build a theoretical framework based on the cost-benefit theory and add habit as a factor to put forward an integrated research model, which explicates people’s continued use of mobile payment services. An online questionnaire was employed to collect empirical data. A total of 295 samples were analyzed using structural equation modeling (SEM) approach. The results showed that both perceived value and habit played an important role in users’ continued intention to use mobile payment services. Also, the perceived benefits (mobile convenience and service compatibility) and perceived costs (security risk and perceived fee) are crucial factors that determine users’ perceived value. In addition, the study also found that perceived value had a positive impact on users’ habit, showing that in the context of a mobile-oriented information system, whether mobile payment services satisfied users’ perceived value influenced the formation of habit of using such services. The implications of these findings are discussed

Promoting Customers’ Augmented Reality Immersion in Restaurants

With the rapid growth of augmented reality (AR) applications, AR is set to influence companies and organizations in every industry. This study focuses on identifying how AR technology enhances memorable experiences through the lens of customer immersion. An AR 3D food ordering platform that included an AR food ordering app for customers and a restaurant management system for restaurants was implemented as part of the study, and the concept of AR immersion was further introduced. The investigation involved an empirical examination of the effects of perceived playfulness and personal innovativeness on three dimensions of AR immersion: engagement, engrossment, and total immersion. The results of an analysis of data collected from 343 restaurant customers who experienced using the AR food ordering app indicated that engagement and engrossment had direct effects on customer satisfaction, but total immersion did not. Perceived playfulness directly affected engagement, engrossment, and total immersion and indirectly affected customer satisfaction through its direct effects on engagement and engrossment. Similarly, personal innovativeness influenced customer satisfaction indirectly through its direct effects on engagement. In terms of the effects of AR immersion, engrossment should be the target, engagement is insufficient, and total immersion is unnecessary. A practical implication of our findings is that it is possible to increase customer satisfaction directly by increasing the levels of engagement and engrossment with an AR food ordering app

Understanding the antecedents of consumer brand engagement by managing brand communities on social media

As social media provide companies with opportunities to create touch-points by enabling consumers to interact with brands in new ways, a key issue for organizations is how to use brand communities to engage customers and enhance their relationships with brands. Brand community interactivity is one of the latest developments to engage consumers in online brand communities. The objective of brand communities is not only to attract potential customers, but also to retain loyal consumers and gain advocates. Thus, brands and companies’ social media activity should be appropriately organized and managed for high-level consumer brand engagement (CBE), which is a comprehensive construct that allow companies to examine the bond between their brands and consumers. The essence of this CBE bond is related to the involvement of consumers, as it increases the touch-points between them and the brand. This study examined perceived interactivity as a driving factor in the context of a brand community on social media with the purpose of encouraging consumer community engagement, community satisfaction, and consumer brand engagement (CBE). Two second-order constructs were operationalized in the research model. Communication, responsiveness, and control were treated as reflective factors to create the second-order construct “perceived interactivity,” while the other second-order construct “CBE” comprised cognitive processing, affection, and activation as reflective indicators. The results, based on data collected from 328 social media users who are followers of a smartphone brand’s Facebook page, indicated that perceived interactivity is likely to significantly affect consumer community engagement and community satisfaction, which in turn foster brand engagement. Successful social media marketing practices for companies should take responsibility for transforming consumer community engagement into CBE, as it is imperative for organizations building brand communities to enhance their consumer community satisfaction through proper community management to achieve high CBE