Bound states on the lattice with partially twisted boundary conditions

We propose a method to study the nature of exotic hadrons by determining the wave function renormalization constant $Z$ from lattice simulations. It is shown that, instead of studying the volume-dependence of the spectrum, one may investigate the dependence of the spectrum on the twisting angle, imposing twisted boundary conditions on the fermion fields on the lattice. In certain cases, e.g., the case of the $DK$ bound state which is addressed in detail, it is demonstrated that the partial twisting is equivalent to the full twisting up to exponentially small corrections

Microscopic Approach to Shear Viscosities in Superfluid Gases: From BCS to BEC

We compute the shear viscosity, $\eta$, at general temperatures $T$, in a BCS-BEC crossover scheme which is demonstrably consistent with conservation laws. The study of $\eta$ is important because it constrains microscopic theories by revealing the excitation spectra. The onset of a normal state pairing gap and the contribution from pair degrees of freedom imply that $\eta$ at low $T$ becomes small, rather than exhibiting the upturn predicted by most others. Using the local density approximation, we find quite reasonable agreement with just-published experiments.Comment: 4 pages, 2 figure

Government subsidized R&D, project screening, and firms’ innovation: evidence from China

The effects of government subsidies to corporate R&D on firms’ innovation outputs still remain inconclusive in existing studies. Moreover, little is known how the screening system of the public R&D programs influences the effect of such programs. This study examines the effects of Innofund (one of the largest Chinese government programs supporting corporate R&D activities) on firms’ innovation outputs in China. In particular, the project screening mechanism was changed due to policy amendments in 2005. This exogenous policy shock allows us to estimate how the project screening system affects the influence of public R&D subsidies. Based on a panel dataset of Chinese manufacturing firms, we find Innofund-backed firms outperform their non-Innofund-backed counterparts in innovation, measured by the number of patents, new product sales, and the volume of exports after they gained funding. The magnification effects of Innofund are larger after 2005, when the project-screening scheme became more decentralized indicating that decentralized screening functions better in public R&D investment. Finally, the effects of Innofund and the effects of the decentralized screening system that occurred in 2005 vary substantially across markets. The more economically and institutionally developed the market is, the stronger the Innofund effects and the project selection decentralization effects appear. The identification problems are handled by using the propensity score matching approach and the instrumental variable approach.postprin

Comment on "Density and Spin response of a strongly-interacting Fermi gas in the attractive and quasi-repulsive regime"

This is a comment on Phys. Rev. Lett. 108, 080401 (2012) by Palestini et al. We pointed out that the diagrammatic method in that article violates gauge invariance. As a consequence, there will a Meissner effect in the normal phase and the contribution from collective modes are not mentioned in the symmetry-broken phase.Comment: 1 page, no figur

Initial fixation placement in face images is driven by top-down guidance

The eyes are often inspected first and for longer period during face exploration. To examine whether this saliency of the eye region at the early stage of face inspection is attributed to its local structure properties or to the knowledge of its essence in facial communication, in this study we investigated the pattern of eye movements produced by rhesus monkeys (Macaca mulatta) as they free viewed images of monkey faces. Eye positions were recorded accurately using implanted eye coils, while images of original faces, faces with scrambled eyes, and scrambled faces except for the eyes were presented on a computer screen. The eye region in the scrambled faces attracted the same proportion of viewing time and fixations as it did in the original faces, even the scrambled eyes attracted substantial proportion of viewing time and fixations. Furthermore, the monkeys often made the first saccade towards to the location of the eyes regardless of image content. Our results suggest that the initial fixation placement in faces is driven predominantly by ‘top-down’ or internal factors, such as the prior knowledge of the location of “eyes” within the context of a face

Predicting Customer Profitability Dynamically over Time: An Experimental Comparative Study

In this paper a comparative study is presented on dynamic prediction of customer profitability over time. Customer profitability is measured by Re-cency, Frequency, and Monetary (RFM) model. A real transactional data set collected from a UK-based retail is examined for the analysis, and a monthly RFM time series for each customer of the business has been generated accord-ingly. At each time point, the customers can be segmented by using k-means clustering into high, medium, or low groups based on their RFM values. 12 dif-ferent models have been utilized to predict how a customer’s membership in terms of profitability group could evolve over time, including regression, multi-layer perception, and Naïve Bayesian models in open-loop and closed-loop modes. The experimental results have demonstrated a good, consistent and in-terpretable predictability of the RFM time series of interest

Direct Measurement of Piezoelectric Response around Ferroelectric Domain Walls in Crystals with Engineered Domain Configuration

We report the first investigation of the piezoelectric response on a nanoscale in the poled ferroelectric crystals with engineered configuration of domains. Piezoresponse force microscopy of tetragonal 0.63PMN-0.37PT relaxor-based ferroelectric crystals reviled that the d33 piezoelectric coefficient is significantly reduced within the distance of about 1 um from the uncharged engineered domain wall. This finding is essential for understanding the mechanisms of the giant piezoresponse in relaxor-based crystals and for designing new piezoelectric materials