基于区块链技术的数字教育资源评价机制研究——以MOOC平台为例

大规模在线开放课程平台是数字教育资源发布的重要渠道之一,针对其建立科学合理的资源评价机制,对优化数字教育资源环境尤为关键。文章根据慕课平台资源评价机制现状,基于区块链技术构建数字教育资源评价机制,创新性地引入用户信任值,并设计信任值计算模型和评价体系奖惩制度,在激励用户全方位参与到资源评价、扩大现有资源评价参与面的同时,保障用户评价质量;并通过拜占庭容错式的委任权益证明共识机制将各平台优质评价信息上链,有效实现评价信息优胜劣汰、溯源追踪、信息共享。用户可借助平台区块链浏览器高效获取链上存储的优质评价信息,从而降低挑选优质课程资源所需的时间成本。

Molecular simulations of charged complex fluids: A review

Molecular simulation plays an increasingly important role in studying the properties of complex fluid systems containing charges,such as ions,piezoelectric materials,ionic liquids,ionic surfactants,polyelectrolytes,zwitterionic materials,nucleic acids,proteins,biomembranes and etc.,where the electrostatic interactions are of special significance.Several methods have been available for treating the electrostatic interactions in explicit and implicit solvent models.Accurate and efficient treatment of such interactions has therefore always been one of the most challenging issues in classical molecular dynamics simulations due to their inhomogeneity and long-range characteristics.Currently,two major challenges remain in the application field of electrostatic interactions in molecular simulations;(i)improving the representation of electrostatic interactions while reducing the computational costs in molecular simulations;(ii)revealing the role of electrostatic interactions in regulating the specific properties of complex fluids.In this review,the calculation methods of electrostatic interactions,including basic principles,applicable conditions,advantages and disadvantages are summarized and compared.Subsequently,the specific role of electrostatic interactions in governing the properties and behaviors of different complex fluids is emphasized and explained.Finally,challenges and perspective on the computational study of charged systems are given.

Visual tracking based on transfer learning of deep salience information

In this paper,we propose a new visual tracking method in light of salience information and deep learning.Salience detection is used to exploit features with salient information of the image.Complicated representations of image features can be gained by the function of every layer in convolution neural network(CNN).The characteristic of biology vision in attention-based salience is similar to the neuroscience features of convolution neural network.This motivates us to improve the representation ability of CNN with functions of salience detection.We adopt the fully-convolution networks(FCNs)to perform salience detection.We take parts of the network structure to perform salience extraction,which promotes the classification ability of the model.The network we propose shows great performance in tracking with the salient information.Compared with other excellent algorithms,our algorithm can track the target better in the open tracking datasets.We realize the 0.5592 accuracy on visual object tracking 2015(VOT15)dataset.For unmanned aerial vehicle 123(UAV123)dataset,the precision and success rate of our tracker is 0.710 and 0.429.

Experience and inspirations of the Mass Drug Administration Programme with artemisinin-piperaquine in Moheli Island of the Comoros assisted by China

Malaria is one of the major diseases threatening the lives of people in Africa.Over the past decade,China has provided anti-malaria assistance to Africa.In November 2007,fast control malaria team of Guangzhou University of Chinese Medicine cooperated with the Comoros health authority.In Moheli Island of the Comoros,the anti-malaria team adopted a new strategy of Mass Drug Administration(MDA)and active intervention.They established an e ective anti-malaria system and reporting system,as well as a local anti-malaria team.Furthermore,they treated patients with malaria in Moheli Island and implemended health education in local people.In a very short time,they have achieved remarkable results.This paper summarized the experiences of the project in order to provide useful reference for China to better carry out anti-malaria action in Africa and expand foreign health assistance.

Clinical Efficacy and Application Progress of Reduning Injection in Children with Viral Encephalitis

Viral encephalitis in children caused by multiple viral infections,as a common central nervous system disease in pediatrics,has a high incidence in China.Its clinical symptoms usually include infection,poisoning,intracranial hypertension,and disturbance of consciousness.In severe cases,it can even endanger the lives of patient children.At present,the clinical treatment of the viral encephalitis mainly uses traditional Chinese medicine preparations such as Reduning Injection.The efficacy is significant.It can not only relieve the uncomfortable symptoms in a short time,but also has low incidence of adverse reactions.In this study,the factors that cause viral encephalitis in children were analyzed,and the efficacy,pharmacological action and clinical application of Reduning Injection were comprehensively elaborated,to provide a reference for clinical doctors to rationally treat viral encephalitis in children.

Research progress on the main chemical constituents and pharmacological effects of Piper betle L.

The Piper betle,belonging to Piper genus of the Piperaceae family,is an evergreen and perennial creeper used in several traditional medicines.This plant has been known to possess antioxidant,antitumor,antibacterial,anti-inflammatory and antimalarial activities.A wide range of chemical compounds including alkaloids,simple phenylpropanoids,lignans,flavonoids,steroids,triterpenoids,sesquiterpenes,monoterpenes have been isolated from this plant.The present review summarized the information concerning phytochemistry and biological activity of P.betle,providing references for the future research of this plant.

Phenolic compounds from Peanut testa

Phytochemical investigation of peanut testa(the seed coat of Arachis hypogaea L.)led to the isolation of eight phenolic compounds,including caffeic acid(1),methyl caffeate(2),ethyl caffeate(3),methyl protocatechuate(4),ethyl protocatechuate(5),butyl protocatechuate(6),(E)-p-hydroxycinnamic acid methyl ester(7),and resveratrol(8).The structures of the compounds were elucidated through spectroscopic data analysis and comparison with the previously reported literature.Among them,compounds 2,3,5,and 6 were obtained from Arachis hypogaea L.for the first time.

A Novel Hybrid Method to Analyze Security Vulnerabilities in Android Applications

We propose a novel hybrid method to analyze the security vulnerabilities in Android applications.Our method combines static analysis,which consists of metadata and data flow analyses with dynamic analysis,which includes dynamic executable scripts and application program interface hooks.Our hybrid method can effectively analyze nine major categories of important security vulnerabilities in Android applications.We design dynamic executable scripts that record and perform manual operations to customize the execution path of the target application.Our dynamic executable scripts can replace most manual operations,simplify the analysis process,and further verify the corresponding security vulnerabilities.We successfully statically analyze 5547 malwares in Drebin and 10 151real-world applications.The average analysis time of each application in Drebin is 4.52 s,whereas it reaches 92.02 s for real-word applications.Our system can detect all the labeled vulnerabilities among 56 labeled applications.Further dynamic verification shows that our static analysis accuracy approximates 95%for real-world applications.Experiments show that our dynamic analysis can effectively detect the vulnerability named input unverified,which is difficult to be detected by other methods.In addition,our dynamic analysis can be extended to detect more types of vulnerabilities.

Transcriptional and Post-transcriptional Modulation of SQU and KEW Activities in the Control of Dorsal-Ventral Asymmetric Flower Development in Lotus japonicus

In Papilionoideae legume, Lotusjaponicus, the development of dorsal-ventral （DV） asymmetric flowers is mainly controlled by two TB1/CYCLOIDEA/PCF （TCP） genes, SQUARED STANDARD （SQU） and KEELED WINGS IN LOTUS （KEW）, which determine dorsal and lateral identities, respectively. However, the molecular basis of how these two highly homologous genes orchestrate their diverse functions remains unclear. Here, we analyzed their expression levels, and investigated the transcriptional activities of SQUand KEW. We demonstrated that SQU possesses both activation and repression activities, while KEW acts only as an activator. They form homo- and heterodimers, and then collaboraUvely regulate their expression at the transcription level. Furthermore, we identified two types of post-transcriptional modifications, phosphor- ylation and ATP/GTP binding, both of which could affect their transcriptional activities. Mutations in ATP/ GTP binding motifs of SQU and KEW lead to failure of phosphorylation, and transgenic plants bearing the mutant proteins display defective DV asymmetric flower development, indicating that the two conjugate modifications are essential for their diverse functions. Altogether, SQU and KEW activities are precisely modulated at both transcription and post-transcription levels, which might link DV asymmetric flower development to different physiological status and/or signaling pathways.

Dissipation-induced nonreciprocal magnon blockade in a magnon-based hybrid system

We propose an experimentally realizable nonreciprocal magnonic device at the single-magnon level by exploiting magnon block-ade in a magnon-based hybrid system.The coherent qubit-magnon coupling,mediated by virtual photons in a microwave cavity,leads to the energy-level anharmonicity of the composite modes.In contrast,the corresponding dissipative counterpart,induced by traveling microwaves in a waveguide,yields inhomogeneous broadenings of the energy levels.As a result,the cooperative effects of these two kinds of interactions give rise to the emergence of the direction-dependent magnon blockade.We show that this can be demonstrated by studying the equal-time second-order correlation function of the magnon mode.Our study opens an avenue to engineer nonreciprocal magnonic devices in the quantum regime involving only a small number of magnons.

Low-Cost and Scalable Platform with Multiplexed Microwell Array Biochip for Rapid Diagnosis of COVID-19

Sensitive detection of SARS-CoV-2 is of great importance for inhibiting the current pandemic of COVID-19.Here,we report a simple yet efficient platform integrating a portable and low-cost custom-made detector and a novel microwell array biochip for rapid and accurate detection of SARS-CoV-2.The instrument exhibits expedited amplification speed that enables colorimetric read-out within 25 minutes.A polymeric chip with a laser-engraved microwell array was developed to process the reaction between the primers and the respiratory swab RNA extracts,based on reverse transcriptase loop-mediated isothermal amplification(RT-LAMP).To achieve clinically acceptable performance,we synthesized a group of six primers to identify the conserved regions of the ORF1ab gene of SARS-CoV-2.Clinical trials were conducted with 87 PCR-positive and 43 PCRnegative patient samples.The platform demonstrated both high sensitivity(95.40%)and high specificity(95.35%),showing potentials for rapid and user-friendly diagnosis of COVID-19 among many other infectious pathogens.