19,328 research outputs found

    Quintessence Model and Observational Constraints

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    The recent observations of type Ia supernovae strongly support that the universe is accelerating now and decelerated in the recent past. By assuming a general relation between the quintessence potential and the quintessence kinetic energy, a general relation is found between the quintessence energy density and the scale factor. The potential includes both the hyperbolic and the double exponential potentials. A detailed analysis of the transition from the deceleration phase to the acceleration phase is then performed. We show that the current constraints on the transition time, the equation of state and the energy density of the quintessence field are satisfied in the model.Comment: update references,add acknowledgements and correct some errors, accepted for publication in class. and quant. gra

    Studies on bioactive peptide from Chinese soft-shelled turtle (Pelodiscus sinensis) with functionalities of ACE inhibition and antioxidation

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    This paper dealt with a novel anti-hypertensive collagen peptide from Chinese soft-shelled turtle (Pelodiscus sinensis), which was an efficient inhibitor of angiotensin converting enzyme (ACE, EC 3.4.15.1). ACE plays an important physiological role in the regulation of blood pressure by virtue of the rennin angiotensin system. In traditional Chinese medicine, Chinese soft-shelled turtle possesses many health-function properties. This study investigated the effects of Chinese soft-shelled turtle hydrolysate (CTH) on ACE inhibition. The CTH showed limited inhibition effect on ACE with an IC50 value at 280 ± 8 μg/ml, while its graded fraction of molecular weight less than 5000 Da (CTH5K) obtained through membrane ultra filtration exhibited better inhibitory activity (IC50 = 190 ± 5 μg/ml). The antioxidant activity of CTH was also determined by radical scavenging ability. The CTH5K showed higher antioxidant activity. These results indicate that CTH5K possesses potent antihypertensive and antioxidant activity, and provides a bioactive peptide material with potential applications as ingredients in functional foods.Key words: Chinese soft-shelled turtle, collagen peptide, angiotensin converting enzyme inhibitor, antihypertensive, antioxidant

    Coherent Manipulation of Quantum Delta-kicked Dynamics: Faster-than-classical Anomalous Diffusion

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    Large transporting regular islands are found in the classical phase space of a modified kicked rotor system in which the kicking potential is reversed after every two kicks. The corresponding quantum system, for a variety of system parameters and over long time scales, is shown to display energy absorption that is significantly faster than that associated with the underlying classical anomalous diffusion. The results are of interest to both areas of quantum chaos and quantum control.Comment: 6 pages, 4 figures, to appear in Physical Review

    Audeosynth: music-driven video montage

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    We introduce music-driven video montage, a media format that offers a pleasant way to browse or summarize video clips collected from various occasions, including gatherings and adventures. In music-driven video montage, the music drives the composition of the video content. According to musical movement and beats, video clips are organized to form a montage that visually reflects the experiential properties of the music. Nonetheless, it takes enormous manual work and artistic expertise to create it. In this paper, we develop a framework for automatically generating music-driven video montages. The input is a set of video clips and a piece of background music. By analyzing the music and video content, our system extracts carefully designed temporal features from the input, and casts the synthesis problem as an optimization and solves the parameters through Markov Chain Monte Carlo sampling. The output is a video montage whose visual activities are cut and synchronized with the rhythm of the music, rendering a symphony of audio-visual resonance.postprin

    Control of Dynamical Localization

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    Control over the quantum dynamics of chaotic kicked rotor systems is demonstrated. Specifically, control over a number of quantum coherent phenomena is achieved by a simple modification of the kicking field. These include the enhancement of the dynamical localization length, the introduction of classical anomalous diffusion assisted control for systems far from the semiclassical regime, and the observation of a variety of strongly nonexponential lineshapes for dynamical localization. The results provide excellent examples of controlled quantum dynamics in a system that is classically chaotic and offer new opportunities to explore quantum fluctuations and correlations in quantum chaos.Comment: 9 pages, 7 figures, to appear in Physical Review

    Phase Control of Nonadiabaticity-induced Quantum Chaos in An Optical Lattice

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    The qualitative nature (i.e. integrable vs. chaotic) of the translational dynamics of a three-level atom in an optical lattice is shown to be controllable by varying the relative laser phase of two standing wave lasers. Control is explained in terms of the nonadiabatic transition between optical potentials and the corresponding regular to chaotic transition in mixed classical-quantum dynamics. The results are of interest to both areas of coherent control and quantum chaos.Comment: 3 figures, 4 pages, to appear in Physical Review Letter

    Screening of patients with tuberculosis for diabetes mellitus in China.

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    Objective  There is a high burden of both diabetes (DM) and tuberculosis (TB) in China, and this study aimed to assess feasibility and results of screening patients with TB for DM within the routine healthcare setting of six health facilities. Method  Agreement on how to screen, monitor and record was reached in May 2011 at a stakeholders' meeting, and training was carried out for staff in the six facilities in July 2011. Implementation started in September 2011, and we report on 7 months of activities up to 31 March 2012. Results  There were 8886 registered patients with TB. They were first asked whether they had DM. If the answer was no, they were screened with a random blood glucose (RBG) followed by fasting blood glucose (FBG) in those with RBG ≥ 6.1 mm (one facility) or with an initial FBG (five facilities). Those with FBG ≥ 7.0 mm were referred to DM clinics for diagnostic confirmation with a second FBG. Altogether, 1090 (12.4%) patients with DM were identified, of whom 863 (9.7%) had a known diagnosis of DM. Of 8023 patients who needed screening for DM, 7947 (99%) were screened. This resulted in a new diagnosis of DM in 227 patients (2.9% of screened patients), and of these, 226 were enrolled to DM care. In addition, 575 (7.8%) persons had impaired fasting glucose (FBG 6.1 to <7.0 mm). Prevalence of DM was significantly higher in patients in health facilities serving urban populations (14.0%) than rural populations (10.6%) and higher in hospital patients (13.5%) than those attending TB clinics (8.5%). Conclusion  This pilot project shows that it is feasible to screen patients with TB for DM in the routine setting, resulting in a high yield of patients with known and newly diagnosed disease. Free blood tests for glucose measurement and integration of TB and DM services may improve the diagnosis and management of dually affected patients
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