LOCAL STRUCTURE-PRESERVING ALGORITHMS FOR THE KLEIN-GORDON-ZAKHAROV EQUATION

In this paper, using the concatenating method, a series of local structure-preserving algorithms are obtained for the Klein-Gordon-Zakharov equation, including four multisymplectic algorithms, four local energy-preserving algorithms, four local momentumpreserving algorithms;of these, local energy-preserving and momentum-preserving algorithms have not been studied before. The local structure-preserving algorithms mentioned above are more widely used than the global structure-preserving algorithms, since local preservation algorithms can be preserved in any time and space domains, which overcomes the defect that global preservation algorithms are limited to boundary conditions. In particular, under appropriate boundary conditions, local preservation laws are global preservation laws.Numerical experiments conducted can support the theoretical analysis well.

EasyGaze:Hybrid eye tracking approach for handheld mobile devices

Background Eye-tracking technology for mobile devices has made significant progress.However,owing to limited computing capacity and the complexity of context,the conventional image feature-based technology cannot extract features accurately,thus affecting the performance.Methods This study proposes a novel approach by combining appearance-and feature-based eye-tracking methods.Face and eye region detections were conducted to obtain features that were used as inputs to the appearance model to detect the feature points.The feature points were used to generate feature vectors,such as corner center-pupil center,by which the gaze fixation coordinates were calculated.Results To obtain feature vectors with the best performance,we compared different vectors under different image resolution and illumination conditions,and the results indicated that the average gaze fixation accuracy was achieved at a visual angle of 1.93°when the image resolution was 96×48 pixels,with light sources illuminating from the front of the eye.Conclusions Compared with the current methods,our method improved the accuracy of gaze fixation and it was more usable.

Atmospheric Particle Hygroscopicity and the Influence by Oxidation State of Organic Aerosols in Urban Beijing

A hygroscopic tandem differentialmobility analyser(H-TDMA)was used to observe the sizeresolved hygroscopic characteristics of submicron particles in January and April 2018 in urban Beijing.The probability distribution of the hygroscopic growth factor(HGF-PDF)in winter and spring usually showed a bimodal pattern,with more hygroscopic mode(MH)being more dominant.The seasonal variation in particle hygroscopicity was related to the origin of air mass,which received polluted southerly air masses in spring and clean northwesterly air masses in winter.Particles showed stronger hygroscopic behaviour during heavy pollution episodes(HPEs)with elevated concentrations of secondary aerosols,especially higher mass fraction of nitrate,which were indicated using the PM2.5(particulate matter with diameter below 2.5μm)mass concentration normalised by CO mass concentration.The hygroscopic parameter(κ)values were calculated using H-TDMA(κhtdma)and chemical composition(κchem).The closure study showed thatκchem was overestimated in winter afternoon when compared withκhtdma,because the organic particle hygroscopic parameter(κorg)was overestimated in the calculations.It was influenced by the presence of a high concentration of hydrocarbon-like organic aerosol(HOA)with a weak water uptake ability.A positive relationship was observed betweenκorg and the ratio of oxygenated organic aerosol(OOA)and HOA,thereby indicating that the strong oxidation state enhanced the hygroscopicity of the particles.This study revealed the effect of local emission sources and secondary aerosol formation processes on particle hygroscopicity,which is of great significance for understanding the pollution formation mechanism in the North China Plain.

A New Framework of Convergence Analysis for Solving the General Nonlinear Schrodinger Equation using the Fourier Pseudo-Spectral Method in Two Dimensions

This paper aims to build a new framework of convergence analysis of conservative Fourier pseudo-spectral method for the general nonlinear Schr¨odinger equation in two dimensions,which is not restricted that the nonlinear term is mere cubic.The new framework of convergence analysis consists of two steps.In the first step,by truncating the nonlinear term into a global Lipschitz function,an alternative numerical method is proposed and proved in a rigorous way to be convergent in the discrete L2 norm;followed in the second step,the maximum bound of the numerical solution of the alternative numerical method is obtained by using a lifting technique,as implies that the two numerical methods are the same one.Under our framework of convergence analysis,with neither any restriction on the grid ratio nor any requirement of the small initial value,we establish the error estimate of the proposed conservative Fourier pseudo-spectral method,while previous work requires the certain restriction for the focusing case.The error bound is proved to be of O(h^(r)+t^(2))with grid size h and time step t.In fact,the framework can be used to prove the unconditional convergence of many other Fourier pseudo-spectral methods for solving the nonlinear Schr¨odinger-type equations.Numerical results are conducted to indicate the accuracy and efficiency of the proposed method,and investigate the effect of the nonlinear term and initial data on the blow-up solution.

消朦灵对糖尿病大鼠视网膜TNF-α及JAK/STAT信号转导通路的调控作用

目的:探讨消朦灵片对肿瘤坏死因子α(TNF-α)和Janus激酶2/信号转导与转录激活子途径5(JAK2/STAT5)信号通路的调控作用,及防治糖尿病视网膜病变的机理。方法:实验研究。选取50只SD雄性大鼠,随机抽取8只作为空白组。余42只以链脲佐菌素(STZ)腹腔注射诱导制作糖尿病大鼠模型;造模成功40只,随机分成模型组、低剂量组、中剂量组和高剂量组,每组10只。模型组不予处理,低剂量组、中剂量组和高剂量组分别给予消朦灵片0.1g/100g、0.2g/100g、0.3g/100g进行治疗。治疗4个月后观察各组大鼠体质量、血糖变化。通过光学显微镜及透射电子显微镜观察视网膜超微结构变化。采用WesternBlot法检测TNF-α、JAK2/STAT5蛋白表达的变化。对相关数据行重复测量资料的方差分析及单因素方差分析。结果:空白组大鼠视网膜中TNF-α、JAK/STAT有少量表达,模型组表达较多,消朦灵低剂量、中剂量、高剂量组表达依次减少,其中高剂量组表达明显下降,差异有统计学意义(F=4.61、4.23、3.28,P<0.05)。生物光学显微镜下大鼠视网膜结构,空白组结构正常;模型组各层组织排列紊乱,视网膜水肿,毛细血管扩张明显,神经节细胞数量减少,细胞核固缩,内核层空泡变性;高剂量组视网膜各层排列欠规则,轻度水肿,神经节细胞及内核层数量减少。透射电镜下空白组大鼠视网膜结构正常;模型组外节膜盘中段断裂、溶解、溃变,线粒体嵴消失,排列不规则,视锥细胞形态不规则,核中染色质分布不均匀,毛细血管基底膜增厚,管腔狭窄;高剂量组视网膜外节膜盘间隙扩大,排列欠整齐,部分线粒体肿胀变形,视锥细胞核染色欠均匀,毛细血管基底膜厚度不均匀。结论:消朦灵对糖尿病大鼠视网膜中TNF-α、JAK/STAT信号通路有显著的调控作用,能有效防止糖尿病视网膜微血管病变,延缓糖尿病视网膜病变的进程。

Structures of the portal vertex reveal essential protein-protein interactions for Herpesvirus assembly and maturation

Dear Editor,Herpesviridae is a large family of double-stranded DNA(dsDNA)viruses that cause a variety of human diseases ranging from cold sores and chicken pox to congenital defects,blindness and cancer(Chayavichitsilp et al.,2009;Wang et al.,2018).In the past 70 years,substantial advances in our knowledge of the molecular biology of herpesviruses have led to insights into disease pathogenesis and management.However,the mechanism for capsid assembly that requires the ordered packing of about 4,000 protein subunits into the hexons,pentons and triplexes remains elusive.It is still a puzzle how initially identical subunits adopt both hexameric and pentameric conformations in the capsid and select the correct locations needed to form closed shells of the proper size.Biochemical and genetic studies have shown that the portal is involved in initiation of capsid assembly(Newcomb et al.,2005)and functions akin to a DNA-sensor coupling genome-packaging achieved by a genome-packaging machinery-“terminase complex”(Chen et al.,2020;Yunxiang Yang,2020)with icosahedral capsid maturation(Lokareddy et al.,2017).Structural investigations of the herpesvirus portal have proven challenging due to the small size of this dodecamer,which accounts for less than 1%of the total mass of the capsid protein layer and the technical difficulties involved in resolving non-icosahedral components of such large icosahedral viruses(diameter is∼1,250Å).Efforts of many investigators over two decades have made to reconstruct the cryo-electron microscopy(cryo-EM)structure of herpesvirus portal vertex and more recently near-atomic structures of two herpesvirus(herpes simplex virus type 1(HSV-1)and Kaposi’s sarcoma-associated herpesvirus(KSHV))portal vertices were reported(McElwee et al.,2018;Gong et al.,2019;Liu et al.,2019).

Collaborative eye tracking based code review through real-time shared gaze visualization

Code review is intended to find bugs in early development phases,improving code quality for later integration and testing.However,due to the lack of experience with algorithm design,or software development,individual novice programmers face challenges while reviewing code.In this paper,we utilize collaborative eye tracking to record the gaze data from multiple reviewers,and share the gaze visualization among them during the code review process.The visualizations,such as borders highlighting current reviewed code lines,transition lines connecting related reviewed code lines,reveal the visual attention about program functions that can facilitate understanding and bug tracing.This can help novice reviewers to make sense to confirm the potential bugs or avoid repeated reviewing of code,and potentially even help to improve reviewing skills.We built a prototype system,and conducted a user study with paired reviewers.The results showed that the shared real-time visualization allowed the reviewers to find bugs more efficiently.