3,832 research outputs found

    t→cVt\to cV via SUSY FCNC couplings in the unconstrained MSSM

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    We recalculate the branching ratios for t→cVt\to cV (V=g,Îł,ZV=g,\gamma,Z) induced by SUSY FCNC couplings within the general unconstrained MSSM framework using mass eigenstate approach. Our results show that the branching ratios for these decays are larger than ones reported in previous literatures in the MSSM with R-parity conservation, and they can reach ∌10−4\sim 10^{-4}, ∌10−6\sim 10^{-6}, and ∌10−6\sim 10^{-6}, respectively, for favorable parameter values allowed by current precise experiments. Thus, the branching ratios for t→cgt\to cg and t→cÎłt\to c\gamma may be measurable at the LHC.Comment: 15 pages, 3 figures, minor changs in the Table

    Soft Gluon Resummation Effects in Single Slepton Production at Hadron Colliders

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    We investigate QCD effects in the production of a single slepton at hadron colliders in the Minimal Supersymmetric Standard Model without R-parity. We calculate the total cross sections and the transverse momentum distributions at next-to-leading order in QCD. The NLO corrections enhance the total cross sections and decrease the dependence of the total cross sections on the factorization and renormalization scales. For the differential cross sections, we resum all order soft gluon effects to give reliable predictions for the transverse momentum distributions. We also compare two approaches to the non-perturbative parametrization and found that the results are slightly different at the Tevatron and are in good agreement at the LHC. Our results can be useful to the simulation of the events and to the future collider experiments.Comment: 26 pages, 12 figures, RevTeX4; Minor changes; Version to appear in PR

    Rotective effect of Fengliao-Changweikang extracts, a traditional Chinese herbal medicine formula,on mucosa in rat with chronic gastritis

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    Background: Fengliao-Changwei-Kang(FCK), the Chinese patent drug, is a famous traditional Chinese herbal medicine formula. It has a significant effect on the clinic treatment of gastrointestinal diseases  including gastritis, enteritis and diarrhea for many years. However, there is few research on the  protective effects of FCK on the gastric mucosa of chronic gastritis (CG) model rat. Objective: The present study aimed to explore the effects of FCK extract on mucosa in rats with Chronic Gastritis.Materials and Methods: 50 SD mice were randomly divided into 5 groups with 10 in each groupfive per sex). The groups are respectively control group, model group, low, middle and high FCK extracts (FCK I, II and III) group. The CG rat model was induced by synthetic methods. FCK I, II and III group were  administrated with FCK extracts at 2.16g‱ kg, 4.32g‱ kg, 8.94g‱ kg once per day for 21 consecutive  days, and the control group and model group were administrated the same volume of distilled water at 10mL/kg once per day. 16 hours after the last administration, the rats were anesthetized and their blood and stomach were drawn from vena cava and abdominal cavity. The serum levels of EGF was measured by enzyme linked immunosorbent assay(ELISA) method, the expression of growth factor receptor (EGFR) in gastric mucosa was detected by immunohistochemical method, and the mRNA expressions of NF-ÎșB p65 was detected in-situ hybridization.Results: The inflammation grades and the expressions of NF-ÎșB p65 mRNA in gastric mucosa of the model group were markedly higher than those of the control group (P<0.05). The inflammation grades of gastric mucosa and the expressions of NF-ÎșB p65 mRNA in gastric mucosa the FCK extract group are significantly lower than those of the model group, and the FCK extract group at 8.64g/kg could greatly increase the serum levels of EGF and the expressions of EGFR in gastric mucosa. High EGF level was found in FCK extract group at 4.32g/kg, but low in FCK extract groups at 2.16g/kg. There were no marked differences among the rats from control group, model group and FCK extract group on ratio of Ll/L2 (P>0.05).Conclusions: FCK extract could alleviate mucosal inflammation by down regulating the expressions of NF-ÎșB p65 mRNA and promote tissue repair by up regulating EGFR expression in gastric mucosa cell.Keywords: chronic gastritis; fengliao-changwei-kang extract; epidermal growth factor receptor; nuclear factor kappa B

    Threshold Resummation Effects in Direct Top Quark Production at Hadron Colliders

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    We investigate the threshold-enhanced QCD corrections to the cross sections for direct top quark productions induced by model-independent flavor changing neutral current couplings at hadron colliders. We use the soft-collinear effective theory to describe the incoming massless partons and use the heavy quark effective theory to treat the top quark. Then we construct the flavor changing operator based on the above effective theories, and resum the large logarithms near threshold arising from soft gluon emission. Our results show that the resummed QCD corrections further enhance the next-to-leading order cross sections significantly. Moreover, the resummation effects vastly reduce the dependence of the cross sections on the renormalization and factorization scales, especially in cases where the next-to-leading order results behave worse than the leading order results. Our results are more sensitive to the new physics effects. If signals of direct top quark production are found in future experiments, it is more appropriate to use our results as the theoretical inputs for extracting the anomalous couplings.Comment: 5 pages, 4 figures, use revtex4 and amsmath; version to appear in Phys. Rev.

    A Hierarchical Framework of Cloud Resource Allocation and Power Management Using Deep Reinforcement Learning

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    Automatic decision-making approaches, such as reinforcement learning (RL), have been applied to (partially) solve the resource allocation problem adaptively in the cloud computing system. However, a complete cloud resource allocation framework exhibits high dimensions in state and action spaces, which prohibit the usefulness of traditional RL techniques. In addition, high power consumption has become one of the critical concerns in design and control of cloud computing systems, which degrades system reliability and increases cooling cost. An effective dynamic power management (DPM) policy should minimize power consumption while maintaining performance degradation within an acceptable level. Thus, a joint virtual machine (VM) resource allocation and power management framework is critical to the overall cloud computing system. Moreover, novel solution framework is necessary to address the even higher dimensions in state and action spaces. In this paper, we propose a novel hierarchical framework for solving the overall resource allocation and power management problem in cloud computing systems. The proposed hierarchical framework comprises a global tier for VM resource allocation to the servers and a local tier for distributed power management of local servers. The emerging deep reinforcement learning (DRL) technique, which can deal with complicated control problems with large state space, is adopted to solve the global tier problem. Furthermore, an autoencoder and a novel weight sharing structure are adopted to handle the high-dimensional state space and accelerate the convergence speed. On the other hand, the local tier of distributed server power managements comprises an LSTM based workload predictor and a model-free RL based power manager, operating in a distributed manner.Comment: accepted by 37th IEEE International Conference on Distributed Computing (ICDCS 2017

    Sleep-Waking Discharge of Ventral Tuberomammillary Neurons in Wild-Type and Histidine Decarboxylase Knock-Out Mice

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    Using extracellular single-unit recordings, we have determined the characteristics of neurons in the ventral tuberomammillary nucleus (VTM) of wild-type (WT) and histidine decarboxylase knock-out (HDC-KO) mice during the sleep-waking cycle. The VTM neurons of HDC-KO mice showed no histamine immunoreactivity, but were immunoreactive for the histaminergic (HA) neuron markers adenosine deaminase and glutamic acid decarboxylase 67. In the VTM of WT mice, we found waking (W)-specific, non-W-specific W-active, sleep-active, W and paradoxical sleep (PS)-active, and state-indifferent neuron groups. We previously demonstrated in WT mice that only W-specific neurons are histaminergic and that they are characterized by a triphasic broad action potential. In the VTM of HDC-KO mice, we found all these groups of state-dependent and state-indifferent neurons, including W-specific neurons that were characterized by a triphasic broad action potential and a W-specific slow tonic discharge, as in WT mice. The W-specific neurons ceased firing before the onset of electroencephalogram (EEG) synchronization, the first EEG sign of sleep, and remained silent during both slow-wave sleep (SWS) and PS. At the transition from SWS to W, they discharged after the onset of EEG activation, the first EEG sign of W. They either responded to an arousing stimulus with a long delay or did not respond. They therefore presented exactly the same characteristics as those seen in the VTM of WT mice. Thus VTM neurons deprived of their natural transmitter histamine still exhibit the firing properties of W-specific HA neurons
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