4,261 research outputs found

    Measuring the anomalous quartic gauge couplings in the W+W−→W+W−W^+W^-\to W^+W^- process at muon collider using artificial neural networks

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    The muon collider provides a unique opportunity to study the vector boson scattering processes and dimension-8 operators contributing to anomalous quartic gauge couplings. Because of the cleaner final state, it is easier to decode subprocess and certain operator couplings at a muon collider. We attempt to identify the anomalous WWWWWWWW coupling in WW→WWWW\to WW scattering in this paper. The vector boson scattering process corresponding to the anomalous WWWWWWWW coupling is μ+μ−→νννˉνˉℓ+ℓ−\mu^+\mu^-\to \nu\nu\bar{\nu}\bar{\nu}\ell^+\ell^-, with four (anti-)neutrinos in the final state, which pose difficulties for phenomenological studies. In this paper, the machine learning method is used to tackle this problem. We find that, the artificial neural network can be used to extract the W+W−→W+W−W^+W^-\to W^+W^- contribution, and is useful to reconstruct the center of mass energy of the subprocess which is important in the study of the Standard Model effective field theory. The sensitivities and the expected constraints on the dimension-8 operators at the muon collider with s=30\sqrt{s}=30 TeV are presented. The artificial neural networks exhibit great potential in the phenomenological study of processes with multiple neutrinos in the final state.Comment: 26 pages, 11 figures, 7 table

    Spectroscopic visualization of flat bands in magic-angle twisted monolayer-bilayer graphene: localization-delocalization coexisting electronic states

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    Recent transport studies have demonstrated the great potential of twisted monolayer-bilayer graphene (tMBG) as a new platform to host moir\'e flat bands with a higher tunability than twisted bilayer graphene (tBG). However, a direct visualization of the flat bands in tMBG and its comparison with the ones in tBG remain unexplored. Here, via fabricating on a single sample with exactly the same twist angle of ~1.13{\deg}, we present a direct comparative study between tMBG and tBG using scanning tunneling microscopy/spectroscopy. We observe a sharp density of states peak near the Fermi energy in tunneling spectroscopy, confirming unambiguously the existence of flat electronic bands in tMBG. The bandwidth of this flat-band peak is found to be slightly narrower than that of the tBG, validating previous theoretical predictions. Remarkably, by measuring spatially resolved spectroscopy, combined with continuum model calculation, we show that the flat-band states in tMBG exhibit a unique layer-resolved localization-delocalization coexisting feature, which offers an unprecedented possibility to utilize their cooperation on exploring novel correlation phenomena. Our work provides important microscopic insight of flat-band states for better understanding the emergent physics in graphene moir\'e systems.Comment: 15 pages, 4 figure

    Large-scale single-photon imaging

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    Benefiting from its single-photon sensitivity, single-photon avalanche diode (SPAD) array has been widely applied in various fields such as fluorescence lifetime imaging and quantum computing. However, large-scale high-fidelity single-photon imaging remains a big challenge, due to the complex hardware manufacture craft and heavy noise disturbance of SPAD arrays. In this work, we introduce deep learning into SPAD, enabling super-resolution single-photon imaging over an order of magnitude, with significant enhancement of bit depth and imaging quality. We first studied the complex photon flow model of SPAD electronics to accurately characterize multiple physical noise sources, and collected a real SPAD image dataset (64 ×\times 32 pixels, 90 scenes, 10 different bit depth, 3 different illumination flux, 2790 images in total) to calibrate noise model parameters. With this real-world physical noise model, we for the first time synthesized a large-scale realistic single-photon image dataset (image pairs of 5 different resolutions with maximum megapixels, 17250 scenes, 10 different bit depth, 3 different illumination flux, 2.6 million images in total) for subsequent network training. To tackle the severe super-resolution challenge of SPAD inputs with low bit depth, low resolution, and heavy noise, we further built a deep transformer network with a content-adaptive self-attention mechanism and gated fusion modules, which can dig global contextual features to remove multi-source noise and extract full-frequency details. We applied the technique on a series of experiments including macroscopic and microscopic imaging, microfluidic inspection, and Fourier ptychography. The experiments validate the technique's state-of-the-art super-resolution SPAD imaging performance, with more than 5 dB superiority on PSNR compared to the existing methods

    External Application of Traditional Chinese Medicine for Venous Ulcers: A Systematic Review and Meta-Analysis

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    Objective. To evaluate the effectiveness of external application of traditional Chinese medicine (EA-TCM) on venous ulcers. Methods. Seven databases were searched until April 2015 for randomized controlled trials (RCTs) of EA-TCM for venous ulcers. Risk of bias was assessed using Cochrane Handbook guidelines. Study outcomes were presented as risk ratios (RRs) for dichotomous data or mean differences (MDs) for continuous data. Results. Sixteen of 193 potentially relevant trials met the inclusion criteria; however, their methodological qualities were low. Comparison of the same intervention strategies revealed significant differences in total effectiveness rates between EA-TCM and conventional therapy groups (RR = 1.22, 95% confidence interval [CI] = 1.16–1.29, and P<0.00001). Compared to conventional therapy, EA-TCM combined with conventional therapy had a superior total effectiveness rate (RR = 1.11, 95% CI = 1.04–1.19, and P=0.003). There were no significant differences in recurrence rates during followup and final pain measurements between the experimental and those in the control groups (RR = 0.86, 95% CI = 0.31–2.39, and P=0.85; MD −0.75, 95% CI = −2.15–0.65, and P=0.29). Conclusion. The evidence that EA-TCM is an effective treatment for venous ulcers is encouraging, but not conclusive due to the low methodological quality of the RCTs. Therefore, more high-quality RCTs with larger sample sizes are required

    The role of Vps4 in cancer development

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    VPS4 series proteins play a crucial role in the endosomal sorting complexes required for the transport (ESCRT) pathway, which is responsible for sorting and trafficking cellular proteins and is involved in various cellular processes, including cytokinesis, membrane repair, and viral budding. VPS4 proteins are ATPases that mediate the final steps of membrane fission and protein sorting as part of the ESCRT machinery. They disassemble ESCRT-III filaments, which are vital for forming multivesicular bodies (MVBs) and the release of intraluminal vesicles (ILVs), ultimately leading to the sorting and degradation of various cellular proteins, including those involved in cancer development and progression. Recent studies have shown a potential relationship between VPS4 series proteins and cancer. Evidence suggests that these proteins may have crucial roles in cancer development and progression. Several experiments have explored the association between VPS4 and different types of cancer, including gastrointestinal and reproductive system tumors, providing insight into the underlying mechanisms. Understanding the structure and function of VPS4 series proteins is critical in assessing their potential role in cancer. The evidence supporting the involvement of VPS4 series proteins in cancer provides a promising avenue for future research and therapeutic development. However, further researches are necessary to fully understand the mechanisms underlying the relationship between VPS4 series proteins and cancer and to develop effective strategies for targeting these proteins in cancer therapy. This article aims to review the structures and functions of VPS4 series proteins and the previous experiments to analyze the relationship between VPS4 series proteins and cancer

    The Mediating Effects of Stigma on Depressive Symptoms in Patients With Tuberculosis: A Structural Equation Modeling Approach

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    Objectives: To date, the complex interrelationships between family function, doctor-patient communication, knowledge about tuberculosis (TB), stigma, and depressive symptoms among patients with TB are insufficiently understood. We explored the interrelationships between family function, doctor-patient communication, knowledge about TB, TB-related stigma, and depressive symptoms and examined whether TB-related stigma played a mediating role.Methods: A cross-sectional survey was conducted between October 1, 2013 and March 31, 2014 in Hubei province, central China. Data were collected from 1,309 patients with TB using a structured questionnaire that measured family function, doctor-patient communication, knowledge about TB, stigma, and depressive symptoms. Structural equation modeling was used to examine the interrelationships among the study variables based on the hypothesized model.Results: The proposed model provided a good fit to the obtained data. There were indirect effects between family function, doctor-patient communication, knowledge about TB, and depressive symptoms through stigma (β = −0.048, P = 0.002; β = −0.028, P = 0.001; β = −0.021, P = 0.009, respectively). Stigma partially mediated the effect of family function and knowledge about TB on depressive symptoms and fully mediated the effect of doctor-patient communication on depressive symptoms.Conclusions: This study elucidated the pathways linking family function, doctor-patient communication, and knowledge about TB to depressive symptoms and confirmed that the effect of those variables on depressive symptoms can be mediated by stigma. Those findings provide direction and information for depression interventions among patients with TB

    Theory and Experiments of Pressure-Tunable Broadband Light Emission from Self-Trapped Excitons in Metal Halide Crystals

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    Hydrostatic pressure has been commonly applied to tune broadband light emissions from self-trapped excitons (STE) in perovskites for producing white light and study of basic electron-phonon interactions. However, a general theory is still lacking to understand pressure-driven evolution of STE emissions. In this work we first identify a theoretical model that predicts the effect of hydrostatic pressure on STE emission spectrum, we then report the observation of extremely broadband photoluminescence emission and its wide pressure spectral tuning in 2D indirect bandgap CsPb2Br5 crystals. An excellent agreement is found between the theory and experiment on the peculiar experimental observation of STE emission with a nearly constant spectral bandwidth but linearly increasing energy with pressure below 2 GPa. Further analysis by the theory and experiment under higher pressure reveals that two types of STE are involved and respond differently to external pressure. We subsequently survey published STE emissions and discovered that most of them show a spectral blue-shift under pressure, as predicted by the theory. The identification of an appropriate theoretical model and its application to STE emission through the coordinate configuration diagram paves the way for engineering the STE emission and basic understanding of electron-phonon interaction

    A snapshot of the transition from monogenetic volcanoes to composite volcanoes: Case study on the Wulanhada Volcanic Field (northern China)

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    The transition processes from monogenetic volcanoes to composite volcanoes are poorly understood. The Late Pleistocene to Holocene intraplate monogenetic Wulanhada Volcanic Field (WVF) in northern China provides a snapshot of such a transition. Here we present petrographic observations, mineral chemistry, bulk rock major and trace element data, thermobarometry, and a partial melting model for the WVF to evaluate the lithology and partial melting degree of the mantle source, the crystallization conditions, and pre-eruptive magmatic processes occurring within the magma plumbing system. The far-field effect of India-Eurasia collision resulted in a relatively high degree (10 %-20 %) of partial melting of a carbonate-bearing eclogite (~ 3 wt % carbonate; Gt/Cpx ≈ 2 : 8, where Gt denotes garnet and Cpx denotes clinopyroxene) followed by interaction with ambient peridotite. The primary melts ascended to the depth of the Moho (~ 33-36 km depth), crystallized olivine, clinopyroxene and plagioclase at the temperature of 1100-1160 °C with the melt water contents of 1.1 wt %- 2.3 wt %. Part of the primary melt interacted with the lithospheric mantle during ascent, resulting in an increase in the MgO contents and a decrease in the alkaline contents. The modified magma was subsequently directly emplaced into the middle crust (~ 23-26 km depth) and crystallized olivine, clinopyroxene and plagioclase at the temperature of 1100-1160 °C. The primary melts from the same mantle sources migrated upward to the twolevel magma reservoirs to form minerals with complex textures (including reverse and oscillatory zoning and sieve texture). Magma erupted along the NE-SW-striking basement fault and the NW-SE-striking Wulanhada- Gaowusu fault in response to the combined effects of regional tectonic stress and magma replenishment. The crustal magma reservoir in the WVF may represent a snapshot of the transition from monogenetic volcanoes to composite volcanoes. It is possible to form a composite volcano with large magma volumes and complex compositions if the magma is continuously supplied from the source and experiences assimilation and fractional crystallization processes in the magma plumbing system at crustal depth
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