Analysis of the Choice Behaviour towards Docked and Dockless Shared Bicycles based on User Experience

The major cities of China have experienced massive growth in the number and usage of dockless shared bicycle systems, such as Mobike and Ofo, which have replaced the traditional docked bicycle systems that are heavily regulated by local governments. However, docked bicycle systems are still in operation, especially in small and medium-sized cities that have docked shared bicycle systems run by the local government. This study aims to reveal the user choice behaviours for these two shared bicycle systems from the perspective of user experience and to find win-win strategies for the two systems, based on a case study of the Shunde district in Foshan city. The structural equation model and binary logit model are employed to identify the impact factors of the choice behaviours. It is found that user experience plays a key role in the use intention for two kinds of bicycles, including factors such as convenience, riding experience, and level of service. Age is the most important indicator distinguishing the user groups, as older people prefer docked bicycles while younger people prefer dockless ones. Docked and dockless shared bicycle systems operate together harmoniously in Shunde as they satisfy the demands of different user groups with little overlap. It is suggested that a new shared bicycle system, which combines the advantages of both docked and dockless shared bicycles, would be a better solution for small and mid-size cities

Comparison of the efficacy of lamivudine and telbivudine in the treatment of chronic hepatitis B: a systematic review

<p>Abstract</p> <p>Background</p> <p>Chronic viral hepatitis B remains a global public health concern. Currently, several drugs, such as lamivudine and telbivudine, are recommended for treatment of patients with chronic hepatitis B. However, there are no conclusive results on the comparison of the efficacy of lamivudine (LAM) and telbivudine (LdT) in the treatment of chronic hepatitis B.</p> <p>Results</p> <p>To evaluate the comparison of the efficacy of LAM and LdT in the treatment of chronic hepatitis B by a systematic review and meta-analysis of clinical trials, we searched PUBMED (from 1990 to April 2010), Web of Science (from 1990 to April 2010), EMBASE (from 1990 to April 2010), CNKI (National Knowledge Infrastructure) (from 1990 to April 2010), VIP database (from 1990 to April 2010), WANFANG database (from 1990 to April 2010), the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Review. At the end of one-year treatment, LdT was better than LAM at the biochemical response, virological response, HBeAg loss, therapeutic response, while less than at the viral breakthrough and viral resistance, but there was no significant difference in the HBeAg seroconversion and HBsAg response. LdT was better than LAM at the HBeAg seroconversion with prolonged treatment to two years.</p> <p>Conclusions</p> <p>In summary, LdT was superior in inhibiting HBV replication and preventing drug resistance as compared to LAM for CHB patients. But LdT may cause more nonspecific adverse events and can lead to more CK elevation than LAM. It is thus recommended that the LdT could be used as an option for patients but adverse events, for example CK elevation, must be monitored.</p

Contribution of coherent electron production to measurements of heavy-flavor decayed electrons in heavy-ion collisions

Heavy quarks, produced at early stages of heavy-ion collisions, are an excellent probe of the Quark-Gluon Plasma (QGP) also created in these collisions. Electrons from open heavy-flavor hadron decays (HFE) are good proxies for heavy quarks, and have been measured extensively in the last two decades to study QGP properties. These measurements are traditionally carried out by subtracting all known background sources from the inclusive electron sample. More recently, a significant enhancement of e+e- pair production at very low transverse momenta was observed in peripheral heavy-ion collisions. The production characteristics is consistent with coherent photon–photon interactions, which should also constitute a background source to the HFE measurements. In this article, we provide theoretical predictions for the contribution of coherent electron production to HFEs as a function of transverse momentum, centrality and collision energy in Au+Au and Pb+Pb collisions

基于Scopus的植物表型组学研究进展分析

Bibliometric analyses are capable of demonstrating the history and the tendency of scientific and technological development. This article aims to use big scientific data to explore the present status of plant phenomics, based on which sound recommendations could be provided for the development of this emerging research domain. [Methods] Based on academic outputs such as research publications, citations, collaborations, research areas, academic organizations, and authors retrieved from the Scopus database between 2013 and September 2018, statistical analysis tools such as SciVal and CiteSpace 5.0 were applied to quantitatively visualize the development and tendency of plant phenotyping, plant phenomics, and related research areas. [Results] This Scopus-based research has retrieved 20 953 articles that are related to plant phenotyping, plant phenomics, and related applications in plant research, with a total citation of 217 105 and 2.0% of them are TOP1% highly cited papers. According to total citations, the TOP10 countries are the United States, China, Germany, the United Kingdom, France, Japan, Australia, Spain, Canada, and the Netherlands. The TOP10 research organizations based on total citations are Chinese Academy of Sciences (CAS), Institut National de la Recherche Agronomique (INRA), the US Department of Agriculture, Centre National de la Recherche Scientifique (CNRS), Chinese Academy of Agricultural Sciences, Cornell University, Spanish National Research Council, University of California at Davis, Universite Paris-Sacly, and Wageningen University & Research. The scholar with the most academic outputs is Alisdair Robert Fernie at the Koch Planck Institute of Molecular Plant Physiology, Germany. He has published 58 papers using plant cellular phenotypes and was cited 1 246 times. At present, plant phenomics research has focused on a number of plant species, including Arabidopsis, rice, wheat, corn, tomato and soybean. [Conclusion] As an emerging research domain, plant phenomics requires interdisciplinary efforts to integrate agriculture, cultivation, breeding, and other plant biological research with computing sciences. In particular, high-throughput image analysis and related data analysis has become an important research theme at the present stage, with the topical saliency index reaches 98.8%, a very high relevance score

Dynamic Distribution Pruning for Efficient Network Architecture Search

Network architectures obtained by Neural Architecture Search (NAS) have shown state-of-the-art performance in various computer vision tasks. Despite the exciting progress, the computational complexity of the forward-backward propagation and the search process makes it difficult to apply NAS in practice. In particular, most previous methods require thousands of GPU days for the search process to converge. In this paper, we propose a dynamic distribution pruning method towards extremely efficient NAS, which samples architectures from a joint categorical distribution. The search space is dynamically pruned every a few epochs to update this distribution, and the optimal neural architecture is obtained when there is only one structure remained. We conduct experiments on two widely-used datasets in NAS. On CIFAR-10, the optimal structure obtained by our method achieves the state-of-the-art $1.9$\% test error, while the search process is more than $1,000$ times faster (only $1.5$ GPU hours on a Tesla V100) than the state-of-the-art NAS algorithms. On ImageNet, our model achieves 75.2\% top-1 accuracy under the MobileNet settings, with a time cost of only $2$ GPU days that is $100\%$ acceleration over the fastest NAS algorithm. The code is available at \url{ https://github.com/tanglang96/DDPNAS

Construction of regio- and stereoregular poly(enaminone)s by multicomponent tandem polymerizations of diynes, diaroyl chloride and primary amines

Polyhydroaminations for the synthesis of stable nitrogen-substituted conjugated polymers with welldefined structures remain a great challenge and the control of the regio- and stereochemistry of the enamine product of the hydroamination is non-trivial. Herein we report an efficient tandem polymerization of alkynes, carbonyl chlorides and primary amines to afford regio- and stereoregular conjugated poly(enaminone)s. The atom-economical one-pot sequential polycoupling–hydroamination polymerization catalyzed by Pd(PPh3)2Cl2/CuI proceeded smoothly under mild conditions, furnishing nitrogensubstituted conjugated polymers with high molecular weights (up to 46 100) and high regio-/stereoregularities (100%) in nearly quantitative yields (up to 99%). The single crystal structure of the model compound, together with the NMR spectra comparison of the model compound and polymers provided direct insight into the stereo selectivity of the polymerization, verifying the sole Z-vinyleneisomer of the polymers. Through the exquisite structural design strategy of the intramolecular hydrogen bond of the resulting hydroamination product, the tautomerization between enamine and imine as well as E/Z isomerization was successfully avoided, providing products with high chemical stability and sole Z-vinylene isomers. The conjugated polymers display excellent solubility in common organic solvents, good film forming ability, and high thermal stability. The hydrogen bond formation of the polymer helps to block the potential photo-induced electron transfer process and the polymer shows a unique aggregation enhanced emission phenomenon: their solutions are weakly emissive, while their nanoaggregates or thin films are brightly emissive. Furthermore, thin films of the polymers enjoy high refractive indices (1.9103–1.6582) in a wide wavelength region of 400–1000 nm, which can be further modulated by UV irradiation. Meanwhile, well-resolved fluorescent photopatterns of the polymers can be fabricated through the UV irradiation of thin films via a copper photomask

Metadata Caching in Presto: Towards Fast Data Processing

Presto is an open-source distributed SQL query engine for OLAP, aiming for "SQL on everything". Since open-sourced in 2013, Presto has been consistently gaining popularity in large-scale data analytics and attracting adoption from a wide range of enterprises. From the development and operation of Presto, we witnessed a significant amount of CPU consumption on parsing column-oriented data files in Presto worker nodes. This blocks some companies, including Meta, from increasing analytical data volumes. In this paper, we present a metadata caching layer, built on top of the Alluxio SDK cache and incorporated in each Presto worker node, to cache the intermediate results in file parsing. The metadata cache provides two caching methods: caching the decompressed metadata bytes from raw data files and caching the deserialized metadata objects. Our evaluation of the TPC-DS benchmark on Presto demonstrates that when the cache is warm, the first method can reduce the query's CPU consumption by 10%-20%, whereas the second method can minimize the CPU usage by 20%-40%.Comment: 5 pages, 8 figure

Correlations of Baryon and Charge Stopping in Heavy Ion Collisions

Baryon numbers are carried by valence quarks in the standard QCD picture of the baryon structure, while some theory proposed an alternative baryon number carrier, a non-perturbative Y-shaped configuration of the gluon field, called the baryon junction in the 1970s. However, neither of the theories has been verified experimentally. It was recently suggested to search for the baryon junction by investigating the correlation of net-charge and net-baryon yields at midrapidity in heavy-ion collisions. This paper presents studies of such correlations in collisions of various heavy ions from Oxygen to Uranium with the UrQMD Monte Carlo model. The UrQMD model implements valence quark transport as the primary means of charge and baryon stopping at midrapidity. Detailed study are also carried out for isobaric $_{40}^{96}\mathrm{Zr}$ + $_{40}^{96}\mathrm{Zr}$ and $_{44}^{96}\mathrm{Ru}$ + $_{44}^{96}\mathrm{Ru}$ collisions. We found a universal trend of the charge stopping with respect to the baryon stopping, and that the charge stopping is always more than the baryon stopping. This study provides a model baseline in valence quark transport for what is expected in net-charge and net-baryon yields at midrapidity of relativistic heavy-ion collisions.Comment: 6 pages, 7 figure