8,270 research outputs found

    The effect of a very brief smoking-reduction intervention in smokers who have no intention to quit: Study protocol for a randomized controlled trial

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    BACKGROUND: Tobacco use is one of the most common preventable causes of death, but more than half of the Chinese men still use tobacco products. Moreover, 63.6% of Chinese smokers have stated that they would not consider quitting. Specialized and intensive smoking-cessation services are too expensive and passive to have major clinical and public health impacts in developing countries like China. Smoking cessation medications are not covered by medical insurance, and their high price prevents Chinese smokers from using them. Brief interventions are needed to provide cost-effective and timesaving tobacco dependence treatments in China mainland. METHODS/DESIGN: We describe a two-arm randomized controlled trial for smokers who have no intention to quit. The project will be conducted in outpatient clinics at a large hospital in Beijing, China. Both arms include one face-to-face interview plus five follow-up interventions. Each intervention will last approximately one minute. Subjects allocated to the smoking-reduction intervention arm (SRI) will be advised to reduce smoking consumption to at least half of their current consumption level within the next month. All subjects in the SRI will be warned to bear in mind that an attempt to reduce smoking is an intermediate step before complete cessation. Smokers who have successfully reduced their smoking consumption will be encouraged to completely cease smoking. Controls are subjects allocated to the exercise- and diet-advice arm (EDA) and will be given advice about healthy diet and physical activity, but the advice will not include smoking cessation or reduction. Data collection will be done at baseline and at each follow-up interview using standardized questionnaires. The primary outcomes include self-reported and biochemically verified 7-day point prevalence and prolonged abstinence rates at 12-month follow-up. DISCUSSION: We expect that an intention to quit in smoking outpatients can be motivated by physicians in the clinic setting. If this very brief smoking-reduction intervention can be demonstrated to have a positive impact on long-term smoking cessation, this strategy has the potential to be a viable and acceptable approach and may be used widely in China and elsewhere. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: NCT02370147 (date of registration: 23th February, 2015).published_or_final_versio

    Kinks in the dispersion of strongly correlated electrons

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    The properties of condensed matter are determined by single-particle and collective excitations and their interactions. These quantum-mechanical excitations are characterized by an energy E and a momentum \hbar k which are related through their dispersion E_k. The coupling of two excitations may lead to abrupt changes (kinks) in the slope of the dispersion. Such kinks thus carry important information about interactions in a many-body system. For example, kinks detected at 40-70 meV below the Fermi level in the electronic dispersion of high-temperature superconductors are taken as evidence for phonon or spin-fluctuation based pairing mechanisms. Kinks in the electronic dispersion at binding energies ranging from 30 to 800 meV are also found in various other metals posing questions about their origins. Here we report a novel, purely electronic mechanism yielding kinks in the electron dispersions. It applies to strongly correlated metals whose spectral function shows well separated Hubbard subbands and central peak as, for example, in transition metal-oxides. The position of the kinks and the energy range of validity of Fermi-liquid (FL) theory is determined solely by the FL renormalization factor and the bare, uncorrelated band structure. Angle-resolved photoemission spectroscopy (ARPES) experiments at binding energies outside the FL regime can thus provide new, previously unexpected information about strongly correlated electronic systems.Comment: 8 pages, 5 figure

    Spatially resolved ultrafast precessional magnetization reversal

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    Spatially resolved measurements of quasi-ballistic precessional magnetic switching in a microstructure are presented. Crossing current wires allow detailed study of the precessional switching induced by coincident longitudinal and transverse magnetic field pulses. Though the response is initially spatially uniform, dephasing occurs leading to nonuniformity and transient demagnetization. This nonuniformity comes in spite of a novel method for suppression of end domains in remanence. The results have implications for the reliability of ballistic precessional switching in magnetic devices.Comment: 17 pages (including 4 figures), submitted to Phys. Rev. Let

    Entropy Projection Curved Gabor with Random Forest and SVM for Face Recognition

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    In this work, we propose a workflow for face recognition under occlusion using the entropy projection from the curved Gabor filter, and create a representative and compact features vector that describes a face. Despite the reduced vector obtained by the entropy projection, it still presents opportunity for further dimensionality reduction. Therefore, we use a Random Forest classifier as an attribute selector, providing a 97% reduction of the original vector while keeping suitable accuracy. A set of experiments using three public image databases: AR Face, Extended Yale B with occlusion and FERET illustrates the proposed methodology, evaluated using the SVM classifier. The results obtained in the experiments show promising results when compared to the available approaches in the literature, obtaining 98.05% accuracy for the complete AR Face, 97.26% for FERET and 81.66% with Yale with 50% occlusion

    The ηgg\eta^\prime g^* g^* vertex with arbitrary gluon virtualities in the perturbative QCD hard scattering approach

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    We study the ηgg\eta^\prime g^* g^* vertex for arbitrary gluon virtualities in the time-like and space-like regions, using the perturbative QCD hard scattering approach and an input wave-function of the η\eta^\prime-meson consistent with the measured ηγγ\eta^\prime \gamma^* \gamma transition form factor. The contribution of the gluonic content of the η\eta^\prime-meson is taken into account, enhancing the form factor over the entire virtuality considered. However, data on the electromagnetic transition form factor of the η\eta^\prime-meson is not sufficient to quantify the gluonic enhancement. We also study the effect of the transverse momenta of the partons in the η\eta^\prime-meson on the ηgg\eta^\prime g^* g^* vertex, using the modified hard scattering approach based on Sudakov formalism. Analytic expressions for the ηgg\eta^\prime g^* g^* vertex are presented in limiting kinematic regions and parametrizations are given satisfying the QCD anomaly, for real gluons, and perturbative QCD behavior for large gluon virtualities, in both the time-like and space-like regions. Our results have implications for the inclusive decay BηXB \to \eta^\prime X and exclusive decays, such as Bη(K,K)B \to \eta^\prime (K,K^*), and in hadronic production processes N+N(Nˉ)ηXN + N (\bar N) \to \eta^\prime X.Comment: 23 pages, 19 figures (requires revtex4, amssymb, epsf); several typos corrected, this version now identical to the one accepted for publication in Phys. Rev.

    Genetically altered AMPA-type glutamate receptor kinetics in interneurons disrupt long-range synchrony of gamma oscillation

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    Gamma oscillations synchronized between distant neuronal populations may be critical for binding together brain regions devoted to common processing tasks. Network modeling predicts that such synchrony depends in part on the fast time course of excitatory postsynaptic potentials (EPSPs) in interneurons, and that even moderate slowing of this time course will disrupt synchrony. We generated mice with slowed interneuron EPSPs by gene targeting, in which the gene encoding the 67-kDa form of glutamic acid decarboxylase (GAD67) was altered to drive expression of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor subunit GluR-B. GluR-B is a determinant of the relatively slow EPSPs in excitatory neurons and is normally expressed at low levels in γ-aminobutyric acid (GABA)ergic interneurons, but at high levels in the GAD-GluR-B mice. In both wild-type and GAD-GluR-B mice, tetanic stimuli evoked gamma oscillations that were indistinguishable in local field potential recordings. Remarkably, however, oscillation synchrony between spatially separated sites was severely disrupted in the mutant, in association with changes in interneuron firing patterns. The congruence between mouse and model suggests that the rapid time course of AMPA receptor-mediated EPSPs in interneurons might serve to allow gamma oscillations to synchronize over distance

    Satellite estimates of wide-range suspended sediment concentrations in Changjiang (Yangtze) estuary using MERIS data

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    The Changjiang (Yangtze) estuarine and coastal waters are characterized by suspended sediments over a wide range of concentrations from 20 to 2,500 mg l-1. Suspended sediment plays important roles in the estuarine and coastal system and environment. Previous algorithms for satellite estimates of suspended sediment concentration (SSC) showed a great limitation in that only low to moderate concentrations (up to 50 mg l-1) could be reliably estimated. In this study, we developed a semi-empirical radiative transfer (SERT) model with physically based empirical coefficients to estimate SSC from MERIS data over turbid waters with a much wider range of SSC. The model was based on the Kubelka–Munk two-stream approximation of radiative transfer theory and calibrated using datasets from in situ measurements and outdoor controlled tank experiments. The results show that the sensitivity and saturation level of remote-sensing reflectance to SSC are dependent on wavelengths and SSC levels. Therefore, the SERT model, coupled with a multi-conditional algorithm scheme adapted to satellite retrieval of wide-range SSC, was proposed. Results suggest that this method is more effective and accurate in the estimation of SSC over turbid water
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