Anatomy of Bs→PVB_s \to PV decays and effects of next-to-leading order contributions in the perturbative QCD factorization approach

In this paper, we will make systematic calculations for the branching ratios and the CP-violating asymmetries of the twenty one $\bar{B}^0_s \to PV$ decays by employing the perturbative QCD (PQCD) factorization approach. Besides the full leading-order (LO) contributions, all currently known next-to-leading order (NLO) contributions are taken into account. We found numerically that: (a) the NLO contributions can provide $\sim 40\%$ enhancement to the LO PQCD predictions for ${\cal B}(\bar{B}_s^0 \to K^0 \bar{K}^{*0})$ and ${\cal B}(\bar{B}_s^0 \to K^{\pm}K^{*\mp})$, or a $\sim 37\%$ reduction to \calb(\bar{B}_s^0 \to \pi^{-} K^{*+}), and we confirmed that the inclusion of the known NLO contributions can improve significantly the agreement between the theory and those currently available experimental measurements, (b) the total effects on the PQCD predictions for the relevant $B\to P$ transition form factors after the inclusion of the NLO twist-2 and twist-3 contributions is generally small in magnitude: less than $10\%$ enhancement respect to the leading order result, (c) for the "tree" dominated decay $\bar B_s^0\to K^+ \rho^-$ and the "color-suppressed-tree" decay $\bar B_s^0\to \pi^0 K^{*0}$, the big difference between the PQCD predictions for their branching ratios are induced by different topological structure and by interference effects among the decay amplitude ${\cal A}_{T,C}$ and ${\cal A}_P$: constructive for the first decay but destructive for the second one, and (d) for \bar{B}_s^0 \to V(\eta, \etar) decays, the complex pattern of the PQCD predictions for their branching ratios can be understood by rather different topological structures and the interference effects between the decay amplitude \cala(V\eta_q) and \cala(V\eta_s) due to the \eta-\etar mixing.Comment: 18 pages, 2 figures, 3 tables. Some modifications of the text. Several new references are adde

A target guided subband filter for acoustic event detection in noisy environments using wavelet packets

This paper deals with acoustic event detection (AED), such as screams, gunshots, and explosions, in noisy environments. The main aim is to improve the detection performance under adverse conditions with a very low signal-to-noise ratio (SNR). A novel filtering method combined with an energy detector is presented. The wavelet packet transform (WPT) is first used for time-frequency representation of the acoustic signals. The proposed filter in the wavelet packet domain then uses a priori knowledge of the target event and an estimate of noise features to selectively suppress the background noise. It is in fact a content-aware band-pass filter which can automatically pass the frequency bands that are more significant in the target than in the noise. Theoretical analysis shows that the proposed filtering method is capable of enhancing the target content while suppressing the background noise for signals with a low SNR. A condition to increase the probability of correct detection is also obtained. Experiments have been carried out on a large dataset of acoustic events that are contaminated by different types of environmental noise and white noise with varying SNRs. Results show that the proposed method is more robust and better adapted to noise than ordinary energy detectors, and it can work even with an SNR as low as -15 dB. A practical system for real time processing and multi-target detection is also proposed in this work

Study on the Healthy Risk of the Workers: a survey in the Yangtse Rive Delta

Problems of occupational health and safety in small and medium size enterprises are severe in China. With this paucity of official statistics documenting work-related injuries, the auther undertook a project in the Yangtse Rive Delta last year in the hopes of injecting at least some preliminary data into the public discourse. The epidemic of work-related injuries, and the failure of local business and govennnent to address it either through prevention or adequate compensation stems from two functional dimensions: the technical and the institutional. The technical level includes the physical causes of work-related injuries, which are not unique to the Yangtse Rive Delta. The institutional problems, on the other hand, are rooted in China's unique developmental history, politics and growth. These include the absence of legal aid institutions, poor government oversight and official corruption on the local and provincial levels. Key words: healthy risk, workers, survey Résumé: Les problèmes de santé et de sécurité professionnelles dans les petites et moyennes entreprises s’avèrent graves en Chine. Avec l’insuffisance de statistiques officielles documentant l’accident du travail, l’auteur a effectué l’année dernière un projet dans le delta du Yangtsé dans l’espoir d’injecter au moins des données préliminaires dans la conversation du public. L’augmentation des accidents du travail, l’échec des entreprises locales et du gouvernement à résoudre le problème soit par la prévention soit par la compensation adéquate sur les plans technique et institutionnel. Le niveau technique inclut les causes physiques de l’accident du travail qui n’est pas unique dans le delta du Yangtsé. De l’autre côté, les problèmes institutionnels s’enracinent dans l’unique histoire de développement de la Chine, ses politiques et sa croissance, comme l’absence d’aide institutionnelle légale, la vue courte du gouvernement et la corruption des officiers à l’échelle locale et provinciale. Mots-Clés: risque de santé, travailleurs, enquêt

Quantum logical gates with four-level SQUIDs coupled to a superconducting resonator

We propose a way for realizing a two-qubit controlled phase gate with superconducting quantum interference devices (SQUIDs) coupled to a superconducting resonator. In this proposal, the two lowest levels of each SQUID serve as the logical states and two intermediate levels of each SQUID are used for the gate realization. We show that neither adjustment of SQUID level spacings during the gate operation nor uniformity in SQUID parameters is required by this proposal. In addition, this proposal does not require the adiabatic passage or a second-order detuning and thus the gate is much faster.Comment: 6 pages, 3 figure

4-Methyl-1,3-bis­(3,4-methyl­enedioxy­benz­yl)-2-(3,4-methyl­enedioxy­phen­yl)imidazolidine

In the title compound, C27H26N2O6, the imidazolidine ring adopts an envelope conformation. The methyl group on the imidazolidine ring is disordered over two positions with occupancies of 0.517 (11) and 0.483 (11), and the 3,4-methyl­enedioxy­phenyl at the 3-position of imidazolidine ring is also disordered over two positions with occupancies of 0.60 (2) and 0.40 (2)