170 research outputs found

    Analysis of IPO underpricing and influencing factors in China's growth enterprise market

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    IPO underpricing is a common phenomenon in various stock markets, and IPO underpricing is more prominent in China's GEM, which has a relatively short establishment period. Based on the combination of theoretical analysis and empirical research, this dissertation makes a comprehensive investigation of the underpricing of GEM in China, which has certain theoretical and practical significance for improving the financing efficiency of enterprises and improving the operating environment of the GEM market. This article uses the data of 782 listed companies listed on China's GEM from October 2009 to December 2019 as a sample and combines the characteristics of the GEM to select multiple factors that may affect the underpricing rate of the GEM. Through the use of statistical analysis, correlation test, and multiple regression linear models to investigate the influencing factors of underpricing. By dividing the sample into two periods, I find that the relationship between variables and IPO underpricing rate is different in different periods, and shows different significance. Finally, the paper concludes that investors' speculative psychology, ex-ante uncertainty, and underwriter reputation are the reasons for the high underpricing rate of GEM. Based on the above empirical results and analysis, the corresponding suggestions are put forward

    A Deep‐Learning Approach to the Dynamics of Landau–Zenner Transitions

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    Traditional approaches to the dynamics of the open quantum systems with high precision are often resource intensive. How to improve computation accuracy and efficiency for target systems is an extremely difficult challenge. In this work, combining unsupervised and supervised learning algorithms, a deep-learning approach is introduced to simulate and predict Landau–Zenner dynamics. Data obtained from multiple Davydov (Formula presented.) Ansatz with a low multiplicity of four are used for training, while the data from the trial state with a high multiplicity of ten are adopted as target data to assess the accuracy of prediction. After proper training, our method can successfully predict and simulate Landau–Zenner dynamics using only random noise and two adjustable model parameters. Compared to the high-precision dynamics data from multiple Davydov (Formula presented.) Ansatz with a multiplicity of ten, the error rate falls below 0.6%.Ministry of Education (MOE)Accepted versionThe authors gratefully acknowledge the support of the Singapore Ministry of Education Academic Research Fund (Grant Nos. 2018-T1-002-175 and 2020-T1-002- 075)). K. Sun would also like to thank the Natural Science Foundation of Zhejiang Province (Grant No. LY18A040005) for partial support. L.L. Gao acknowledges the support of the Graduate Scientific Research Foundation of Hangzhou Dianzi University

    Corrigendum to “Effect of Taichi Softball on Function-Related Outcomes in Older Adults: A Randomized Control Trial”

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    The purpose of this present study was to examine the effect of Taichi softball (TCSB) on physical function in Chinese older adults. Eighty Chinese older adults were randomly assigned into either an experimental group experiencing four 90-minute TCSB sessions weekly for seven consecutive weeks or a control group. At baseline and 7 weeks later, all participants were asked to perform physical functional tests for both lower and upper limbs. Multiple separate Analyses of Variance (ANOVA) with repeated measures were applied to evaluate the effects of TCSB on function-related outcomes between baseline and postintervention in the two groups. The findings indicate that a short-term and intensive TCSB training program does not only improve low limb-related physical function such as dynamic balance and leg strength, but also strengthen upper limb-related physical function (e.g., arm and forearm strength, shoulder mobility, fine motor control, handgrip strength, and fine motor function). Health professionals could take into account TCSB exercise as an alternative method to help maintain or alleviate the inevitable age-related physical function degeneration in healthy older adults. In addition, researchers could investigate the effect of TCSB exercise on physical function in special populations such as patients with different chronic diseases or neurological disorder (e.g., Parkinson’s disease)

    Mechanical thrombectomy with intra-arterial alteplase provided better functional outcomes for AIS-LVO: a meta-analysis

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    BackgroundSeveral clinical trials have shown that intra-arterial thrombolysis using alteplase during mechanical thrombectomy (MT) has a better outcome than MT alone in ischemic stroke management. We performed the current meta-analysis to estimate the efficacy and safety of MT with intra-arterial alteplase therapy.MethodsThe MEDLINE, Embase, Cochrane Library, and ClinicalTrials.gov databases were searched up to Mar. 2022 to identify the clinical trials that compared MT alone versus MT with intra-arterial alteplase therapy. STATA 16.0 was used for statistical analysis. The odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated with a random effect model.ResultsSeven studies involving 1,083 participants were included. The primary outcomes were better functional outcomes, defined as a modified Rankin Scale (mRS) score between 0 and 2 at 90  days, and successful recanalization, defined as a modified thrombolysis in cerebral infarction (mTICI) score  ≥  2b. Compared to MT alone, MT with intra-arterial alteplase did not lead to higher mTICI scores (OR 1.58, 95%CI 0.94 to 2.67, p = 0.085, I2 = 16.8%) but did lead to better mRS (OR 1.37, 95%CI 1.01 to 1.86, p = 0.044). There was no increase in mortality or bleeding events in the overall or subgroup analyses.ConclusionMT with intra-arterial alteplase did not improve the recanalization rate but provided better functional outcomes. The intervention did not increase adverse effects in any subgroup at the same time.Clinical trial registrationhttp://inplasy.com, identifier INPLASY202240027

    Increasing Diversion of Methadone in Vancouver, Canada, 2005-2015

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    Background and Aim: Although methadone, an opioid agonist, has been an effective medication used to treat opioid use disorder for over 40 years, recent studies have found that methadone was identified in more than a quarter of prescription opioid-related deaths among people who use illicit drugs in Vancouver, Canada. Thus, we sought to longitudinally examine the availability of diverted methadone among people who inject drugs (PWID). Design and Methods: Data were collected from three prospective cohorts of PWID in Vancouver, Canada between December 2005 and May 2015. Multivariable generalized estimating equation logistic regression was used to identify temporal trends in the immediate availability of diverted methadone (defined as the ability to acquire illicit methadone in <10 minutes). Results: A total of 2092 participants, including 727 (34.8%) women, were included in the present study. In the multivariable analyses after adjusting for a range of potential confounders, later calendar year (adjusted odds ratio [AOR] = 1.21 per year; 95% confidence interval [CI]: 1.19–1.23) was independently and positively associated with reporting immediate availability of diverted methadone. Conclusions: We observed a significant increase in the reported availability of diverted methadone among PWID over a ten-year follow-up period. Further research is needed to identify strategies to limit methadone diversion and assess the impact of alternative medications that are equally effective but safer, such as buprenorphine/naloxone

    Highly tunable β-relaxation enables the tailoring of crystallization in phase-change materials

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    In glasses, secondary (β-) relaxations are the predominant source of atomic dynamics. Recently, they have been discovered in covalently bonded glasses, i.e., amorphous phase-change materials (PCMs). However, it is unclear what the mechanism of β-relaxations is in covalent systems and how they are related to crystallization behaviors of PCMs that are crucial properties for non-volatile memories and neuromorphic applications. Here we show direct evidence that crystallization is strongly linked to β-relaxations. We find that the β-relaxation in Ge15Sb85 possesses a high tunability, which enables a manipulation of crystallization kinetics by an order of magnitude. In-situ synchrotron X-ray scattering, dielectric functions, and ab-initio calculations indicate that the weakened β-relaxation intensity stems from a local reinforcement of Peierls-like distortions, which increases the rigidity of the bonding network and decreases the dynamic heterogeneity. Our findings offer a conceptually new approach to tuning the crystallization of PCMs based on manipulating the β-relaxations
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