4,569 research outputs found

    The DρD\to \rho semileptonic and radiative decays within the light-cone sum rules

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    The measured branching ratio of the DD meson semileptonic decay Dρe+νeD \to \rho e^+ \nu_e, which is based on the 0.82 fb10.82~{\rm fb^{-1}} CLEO data taken at the peak of ψ(3770)\psi(3770) resonance, disagrees with the traditional SVZ sum rules analysis by about three times. In the paper, we show that this discrepancy can be eliminated by applying the QCD light-cone sum rules (LCSR) approach to calculate the DρD\to \rho transition form factors A1,2(q2)A_{1,2}(q^2) and V(q2)V(q^2). After extrapolating the LCSR predictions of these TFFs to whole q2q^2-region, we obtain 1/Vcd2×Γ(Dρeνe)=(55.459.41+13.34)×1015 GeV1/|V_{\rm cd}|^2 \times \Gamma(D \to \rho e \nu_e) =(55.45^{+13.34}_{-9.41})\times 10^{-15}~{\rm GeV}. Using the CKM matrix element and the D0(D+)D^0(D^+) lifetime from the Particle Data Group, we obtain B(D0ρe+νe)=(1.7490.297+0.421±0.006)×103{\cal B} (D^0\to \rho^- e^+ \nu_e) = (1.749^{+0.421}_{-0.297}\pm 0.006)\times 10^{-3} and B(D+ρ0e+νe)=(2.2170.376+0.534±0.015)×103{\cal B} (D^+ \to \rho^0 e^+ \nu_e) = (2.217^{+0.534}_{-0.376}\pm 0.015)\times 10^{-3}, which agree with the CLEO measurements within errors. We also calculate the branching ratios of the two DD meson radiative processes and obtain B(D0ρ0γ)=(1.7440.704+0.598)×105{\cal B}(D^0\to \rho^0 \gamma)= (1.744^{+0.598}_{-0.704})\times 10^{-5} and B(D+ρ+γ)=(5.0340.958+0.939)×105{\cal B}(D^+ \to \rho^+ \gamma) = (5.034^{+0.939}_{-0.958})\times 10^{-5}, which also agree with the Belle measurements within errors. Thus we think the LCSR approach is applicable for dealing with the DD meson decays.Comment: 12 pages, 7 figures, version to be published in EPJ

    GeV Scale Asymmetric Dark Matter from Mirror Universe: Direct Detection and LHC Signatures

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    Mirror universe is a fundamental way to restore parity symmetry in weak interactions. It naturally provides the lightest mirror nucleon as a unique GeV-scale asymmetric dark matter particle candidate. We conjecture that the mirror parity is respected by the fundamental interaction Lagrangian, and its possible soft breaking arises only from non-interaction terms in the gauge-singlet sector. We realize the spontaneous mirror parity violation by minimizing the vacuum Higgs potential, and derive the corresponding Higgs spectrum. We demonstrate that the common origin of CP violation in the visible and mirror neutrino seesaws can generate the right amount of matter and mirror dark matter via leptogenesis. We analyze the direct detections of GeV-scale mirror dark matter by TEXONO and CDEX experiments. We further study the predicted distinctive Higgs signatures at the LHC.Comment: 16pp. Plenary talk presented by HJH at the International Symposium on Cosmology and Particle Astrophysics (CosPA2011). To appear in the conference proceedings of IJMP. Minor refinement

    Possible Involvement of µ

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    Recently μ opioid receptor (MOR) has been shown to be closely associated with depression. Here we investigated the action of Shuyu, a Chinese herbal prescription, on repeated restraint stress induced depression-like rats, with specific attention to the role of MOR and the related signal cascade. Our results showed that repeated restraint stress caused significant depressive-like behaviors, as evidenced by reduced body weight gain, prolonged duration of immobility in forced swimming test, and decreased number of square-crossings and rearings in open field test. The stress-induced depression-like behaviors were relieved by Shuyu, which was accompanied by decreased expression of MOR in hippocampus. Furthermore, Shuyu upregulated BDNF protein expression, restored the activity of CREB, and stimulated MEK and ERK phosphorylation in hippocampus of stressed rats. More importantly, MOR is involved in the effects of Shuyu on these depression-related signals, as they can be strengthened by MOR antagonist CTAP. Collectively, these data indicated that the antidepressant-like properties of Shuyu are associated with MOR and the corresponding CREB, BDNF, MEK, and ERK signal pathway. Our study supports clinical use of Shuyu as an effective treatment of depression and also suggests that MOR might be a target for treatment of depression and developing novel antidepressants

    Bidirectional Correlation-Driven Inter-Frame Interaction Transformer for Referring Video Object Segmentation

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    Referring video object segmentation (RVOS) aims to segment the target object in a video sequence described by a language expression. Typical multimodal Transformer based RVOS approaches process video sequence in a frame-independent manner to reduce the high computational cost, which however restricts the performance due to the lack of inter-frame interaction for temporal coherence modeling and spatio-temporal representation learning of the referred object. Besides, the absence of sufficient cross-modal interactions results in weak correlation between the visual and linguistic features, which increases the difficulty of decoding the target information and limits the performance of the model. In this paper, we propose a bidirectional correlation-driven inter-frame interaction Transformer, dubbed BIFIT, to address these issues in RVOS. Specifically, we design a lightweight and plug-and-play inter-frame interaction module in the Transformer decoder to efficiently learn the spatio-temporal features of the referred object, so as to decode the object information in the video sequence more precisely and generate more accurate segmentation results. Moreover, a bidirectional vision-language interaction module is implemented before the multimodal Transformer to enhance the correlation between the visual and linguistic features, thus facilitating the language queries to decode more precise object information from visual features and ultimately improving the segmentation performance. Extensive experimental results on four benchmarks validate the superiority of our BIFIT over state-of-the-art methods and the effectiveness of our proposed modules

    N-Methyl-4-nitro­anilinium chloride

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    The asymmetric unit of the title salt, C7H9N2O2 +·Cl−, contains two independent cations and anions. In the crystal, each N-methyl-4-nitro­anilinium cation is linked to two Cl− anions via N—H⋯Cl hydrogen bonds. π–π stacking is observed between the benzene rings of adjacent cations [centroid-to-centroid distances = 3.7684 (14) and 3.7917 (7) Å]

    Dexmedetomidine post-treatment attenuates cardiac ischaemia/reperfusion injury by inhibiting apoptosis through HIF-1α signalling.

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    Hypoxia-inducible factor 1α (HIF-1α) plays a critical role in the apoptotic process during cardiac ischaemia/reperfusion (I/R) injury. This study aimed to investigate whether post-treatment with dexmedetomidine (DEX) could protect against I/R-induced cardiac apoptosis in vivo and in vitro via regulating HIF-1α signalling pathway. Rat myocardial I/R was induced by occluding the left anterior descending artery for 30 minutes followed by 6-hours reperfusion, and cardiomyocyte hypoxia/reoxygenation (H/R) was induced by oxygen-glucose deprivation for 6 hours followed by 3-hours reoxygenation. Dexmedetomidine administration at the beginning of reperfusion or reoxygenation attenuated I/R-induced myocardial injury or H/R-induced cell death, alleviated mitochondrial dysfunction, reduced the number of apoptotic cardiomyocytes, inhibited the activation of HIF-1α and modulated the expressions of apoptosis-related proteins including BCL-2, BAX, BNIP3, cleaved caspase-3 and cleaved PARP. Conversely, the HIF-1α prolyl hydroxylase-2 inhibitor IOX2 partly blocked DEX-mediated cardioprotection both in vivo and in vitro. Mechanistically, DEX down-regulated HIF-1α expression at the post-transcriptional level and inhibited the transcriptional activation of the target gene BNIP3. Post-treatment with DEX protects against cardiac I/R injury in vivo and H/R injury in vitro. These effects are, at least in part, mediated via the inhibition of cell apoptosis by targeting HIF-1α signalling
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