Examining the evolution of tidal creeks in the Huanghe River delta using multi-temporal Landsat images

Coastal tidal creeks are important channels for exchanges of material and energy between sea and land,and play an important role in the ecological protection of tidal flats.Although tidal creeks have evolved differently in various regions,the evolutionary process of tidal creeks in the Huanghe(Yellow)River delta of China,one of the most active deltas worldwide,is not entirely clear.Therefore,the evolution of tidal creeks in the delta from 1981 to 2021 was investigated by quantitatively analysing the tidal creeks and developing a standard for dividing their evolution periods.Visual interpretation and supervised classification methods were applied to the Landsat images to extract the tidal creek network,and 17 groups of tidal creek systems were selected.Results indicate that Creek S 1 was the most developed creek for having 113 tidal creeks totaling 65.8 km in length,while Creek E 3 had the fastest growth rate for having average annual increase of 1.9 km.Meanwhile,the level of tidal creeks increased,the average and median lengths of tidal creeks increased,and the number of tidal creeks decreased since 1981.The evolution of the tidal creek system could be divided into four stages,namely,rising,developing,stabilizing,and degrading.Analyses of a representative tidal creek show that there was no degenerated tidal creek during the rising period,with an increase in the number of 50 and a length increase of 57.9 km between 1981 and 1989.The proportion of new tidal creeks in the developing period was more than 50%and the new tidal creeks in the stabilizing period were equal to the degraded tidal creeks.Extinct tidal creeks were greater than 50%during the degrading period.There was no fixed order of tidal creek evolution in each period,and there may be a skip in evolution.Our findings provided a reference for studying the evolution of tidal creeks.

Investigation on Diseases and Pests of Grape Under Rain Shelter Cultivation in Shandong Province

In order to make clear the effects of rain shelter cultivation on the incidence of diseases and pests of grape in Shandong Province,with Summer Black as the material,the diseases and pests of grape under rain shelter cultivation and open field cultivation in Tai'an and Jining were investigated.The results showed that under the rain shelter cultivation condition,the phenological period of grape delayed 5-8 d.The types of grape diseases and pests under the rain shelter cultivation were the same as those in the open filed cultivation.The most serious pests were Apolygus lucorum,followed by Lycorma delicatula,Erythreura apicalis and Thrips tabaci.The most serious leaf disease was downy mildew,and the most serious disease of grape berries was grape sour rot.Compared with the open field cultivation,the rain shelter cultivation could effectively reduce the incidence of pests and diseases in grape leaves and fruit.At the end of May 2018 and 2019,the occurrence rate of grape pests under the rain shelter cultivation in Tai'an reduced by 57.69%and 60.47%,respectively,and those in Jining reduced by 72.22%and 62.50%,respectively.In the middle of July of 2018 and 2019,the incidence of grape fruit diseases under the rain shelter cultivation in Tai'an reduced by 62.49%and 50.07%,respectively,and that in Jining reduced by 49.96%and 100%,respectively.

A Multi-Level Authorization Based Tenant Separation Mechanism in Cloud Computing Environment

Separation issue is one of the most important problems about cloud computing security. Tenants should be separated from each other based on cloud infrastructure and different users from one tenant should be separated from each other with the constraint of security policies. Learning from the notion of trusted cloud computing and trustworthiness in cloud, in this paper, a multi-level authorization separation model is formally described, and a series of rules are proposed to summarize the separation property of this model. The correctness of the rules is proved. Furthermore, based on this model, a tenant separation mechanism is deployed in a real world mixed-critical information system. Performance benchmarks have shown the availability and efficiency of this mechanism.

TMSN-AA纳米复合物促进人胚胎干细胞向心肌细胞分化的潜在机制研究

目的研究优化后的TMSN-AA纳米复合物促进人胚胎干细胞(h ESCs)心肌分化的可能性,并探讨其诱导心肌分化的潜在机制。方法采用优化抗坏血酸(AA)负载的荧光TRITC介孔二氧化硅纳米粒子(TMSN-AA)作为诱导剂,诱导h ESCs细胞心肌分化。通过荧光定位检测该诱导剂进入细胞情况,流式细胞仪检测其进入细胞后对细胞存活与凋亡的影响,Western blot检测TMSN-AA诱导后,心肌标记基因cTn I、FLK-1以及干性基因OCT4和SOX2的表达以及相关信号通路ERK1/2的激活情况。结果荧光定位发现TMSN-AA可以靶向进入h ESCs细胞,流式细胞仪分析结果显示,二氧化硅和荧光染料四甲基罗丹明修饰介孔二氧化硅不会影响h ESCs的存活和凋亡;且TMSN-AA诱导后,干性基因OCT4和SOX2均下调,且上调心肌标记基因c Tn I和FLK-1的表达。Western blot检测结果显示,TMSN-AA的处理可以激活ERK1/2信号通路,同时证实,该过程Akt信号通路并未参与其中。结论优化后的TMSN-AA纳米载体可以成功进入h ESCs细胞,并靶向诱导其心肌分化,而该诱导过程,至少在一定程度上是通过激活ERK1/2,而不是Akt信号通路实现的。

Risk factors for proton pump inhibitor refractoriness in Chinese patients with non-erosive reflux disease

AIM:To analyze risk factors for refractoriness to proton pump inhibitors(PPIs) in patients with non-erosive reflux disease(NERD).METHODS:A total of 256 NERD patients treated with the PPI esomeprazole were enrolled.They were classified into symptom-free and residual symptoms groups according to Quality of Life in Reflux and Dyspepsia(QolRad) scale.All subjects completed questionnaires on psychological status(self-rating anxiety scale;selfrating depression scale) and quality of life scale(Short Form 36).Multivariate analysis was used to determine the predictive factors for PPI responses.RESULTS:According to QolRad,97 patients were confirmed to have residual reflux symptoms,and the remaining 159 patients were considered symptom free.There were no significant differences between the two groups in lifestyle factors(smoking and alcohol consumption),age,Helicobacter pylori infection,and hiatal hernia.There were significant differences between the two groups in relation to sex,psychological distress including anxiety and depression,body mass index(BMI),and irritable bowel syndrome(IBS)(P < 0.05).Logistic regression analysis found that BMI < 23,comorbid IBS,anxiety,and depression were major risk factors for PPI resistance.Symptomatic patients had a lower quality of life compared with symptom-free patients.CONCLUSION:Some NERD patients are refractory to PPIs and have lower quality of life.Residual symptoms are associated with psychological distress,intestinal disorders,and low BMI.

Distribution and release of 2,4,5-trichlorobiphenyl in ice

The distribution of persistent organic pollutants（POPs） in ice and the release of POPs from ice during ice melting have an important influence on the eco-environment and water quality of a river. Through laboratory simulation experiments, the distribution and release of 2,4,5-trichlorobiphenyl（PCB29） in ice and the partition coefficients of PCB29 in ice water at different temperatures, concentrations, and p H levels were studied. The results showed that, at different temperatures and concentrations, the concentration of PCB29 in ice increased progressively with depth. The modes of release of different concentrations of PCB29 from ice were obtained. A large amount of PCB29 was released rapidly in the first melting period, and then the remaining PCB29 was released uniformly. The p H value dominated both the distribution and late release of PCB29 in ice. In ice water, at different temperatures, concentrations, and p H levels, the majority of PCB29 entered the water, and a lesser amount remained in the ice. Finally, laboratory experiment results were verified with field investigations. A theoretical framework is provided by this research of the behavior of POPs in ice under different environmental conditions, but a more quantitative understanding of the behavior of POPs in ice will need to be developed through further laboratory studies combined with field investigations.

Performance Analysis for Multimedia Communication Systems with a Multilayer Queuing Network Model

Software performance evaluation in multimedia communication systems is typically formulated into a multi-layered client-server queuing network(MLCSQN) problem. However, the existing analytical methods to MLCSQN model cannot provide satisfactory solution in terms of accuracy, convergence and consideration of interlocking effects. To this end, this paper proposes a heuristic solving method for MLCSQN model to boost the performance prediction of distributed multimedia software systems. The core concept of this method is referred to as the basic model, which can be further decomposed into two sub-models: client sub-model and server sub-model. The client sub-model calculates think time for server sub-model, and the server sub-model calculates waiting time for client sub-model. Using a breadthfirst traversal from leaf nodes to the root node and vice versa, the basic model is then adapted to MLCSQN, with net sub-models iteratively resolved. Similarly, the interlocking problem is effectively addressed with the help of the basic model. This analytical solver enjoys advantages of fast convergence, independence on specific average value analysis(MVA) methods and eliminating interlocking effects.Numerical experimental results on accuracy and computation efficiency verify its superiority over anchors.

A New Perspective to Evaluate Doppler Vascular Impedance in Hypertensive Disorders Complicating Pregnancy: Multilevel Modeling Established in a Case Control Study

Background: There have been researches on the evaluation of Doppler vascular impedance in hypertensive disorders complicating pregnancy (HDCP). With respect to the method of analysis used and the conclusions drawn in previous studies, different vessels were usually viewed separately and independently. This study was designed to evaluate Doppler vascular impedance changes in HDCP from a new perspective, with original thought and insight into an ordinary issue. Methods: 273 pregnant women (110 hypertensive pregnancies and 163 normotensive pregnancies) were randomly included in a grouping case-control study conducted from February 10, 2011 to April 30, 2013. All women in the study underwent Doppler measurements of six different vessels including the umbilical artery, the uterine arteries, the placental bed spiral artery, the fetal middle cerebral artery and the fetal renal artery. Doppler vascular impedance was presented as pulsatility index (PI), resistance index (RI), and systolic and diastolic ratio (S/D). Doppler changes in the hypertensive and normotensive groups were assessed by the multilevel modeling approach with univariate and multivariate-adjusted analyses. Results: According to multilevel modeling approach with multivariate-adjusted analysis, a relatively average evaluation on Doppler vascular impedance was provided. Hypertension was significantly associated with positive effects on PI, RI and S/D values (coefficients were 0.10, 0.03 and 0.08, respectively;95% CIs were 0.06 - 0.14, 0.02 - 0.04 and 0.04 - 0.11, respectively;P values were all less than 0.001) in comparison with normotensive group. Conclusion: According to an overall evaluation, Doppler vascular impedance in hypertensive disorders complicating pregnancy was higher than in normotensive pregnancy. The novel thought and approach applied in this research may bring about inspirations for better understanding and assessment of the disease.

Absorption of Iodide Ions in Aqueous Solution by ZIF-67 and ZIF-8

Two zeolite-like imidazate metal-framework materials ZIF-67 and ZIF-8 were synthesized by using Co(NO_(3))2,Zn(NO_(3))_(2),2-methyl imidazole and methanol as raw materials,and these two materials were used to adsorb iodine ions in water.The impact of pH,contact time and temperature etc.on the adsorption capability of iodide ions in aqueous solutions by the two ZIF materials was investigated.The results show that the optimal adsorption pH was 7,and the optimal adsorption time was 18 h.The adsorption of iodide ions by ZIF-67 was consistent with the Langmuir adsorption isotherm,while the absorption of iodide ions by ZIF-8 was in better consistency with the Freundlich adsorption isotherm.The maximum adsorption capacity of iodide ions by ZIF-67 and ZIF-8 was 141.81 and 474.02 mg/g respectively.The adsorption of iodide ions by the two materials was more in line with the quasi-first-order kinetic model,and the adsorption was monolayer adsorption.

3D Perception Algorithms: Towards Perceptually Driven Compression of 3D Video

In this paper, we summarize 3D perception-oriented algorithms for perceptually driven 3D video coding. Several perceptual ef- fects have been exploited for 2D video viewing; however, this is not yet the case for 3D video viewing. 3D video requires depth perception, which implies binocular effects such as con fl icts, fusion, and rivalry. A better understanding of these effects is necessary for 3D perceptual compression, which provides users with a more comfortable visual experience for video that is de- livered over a channel with limited bandwidth. We present state-of-the-art of 3D visual attention models, 3D just-notice- able difference models, and 3D texture-synthesis models that address 3D human vision issues in 3D video coding and trans-mission.

Technical Regulations for Rain Shelter Cultivation of Summer Black Grape

The Technical Regulations for Rain Shelter Cultivation of Summer Black Grape(T/SDAS 36-2018)stipulates the terms and definitions of rain shelter cultivation technique of summer black grape,producing area environment,construction of rain shelter,seedling planting,types and con-struction of grape trellis,training and pruning,flower and fruit management,water and fertilizer management,disease and pest control,harvest,packing and storage,etc.,which is suitable for summer black grape planting in Shandong and the areas of the same ecological type in China.

Effect of Shoot-Fruit Ratio on Grape Yield,Quality and Storage Nutrient

With the grape variety ＂Summer Black＂ as the test material, the effects of different shoot-fruit ratios on grape yield, fruit quality and grapevine storage nutrient were investigated for 2 consecutive years, so as to determine the optimized load for Summer Black grapes in Shandong. The results showed that the grapes with shoot-fruit ratio of 1∶ 1 had the highest soluble solid content, vitamin C content and grapevine storage nutrient. Based on the comprehensive analysis, the shoot-fruit ratio of 1∶ 1 was the optimized load for Summer Black grapes in Tai an of Shandong Province, and the yield was 1 179.37-1 288.63 kg per 667 m^2.

Analysis of Influencing Factors of Preeclampsia on Postpartum Hemorrhage

Postpartum hemorrhage is a serious complication of preeclampsia.The main influencing factors of Preeclampsia on postpartum hemorrhage include vascular disease,trophoblast differentiation and infiltration disorder,the influence of antispasmodic,sedative and antihypertensive drugs,the incidence of hypertensive disorder complicating pregnancy related to calcium deficiency,coagulation dysfunction,and decreased blood volume during pregnancy.In recent years,postpartum hemorrhage has been the leading cause of maternal death in the world.Therefore,it is critical to understand the influencing factors of preeclampsia on postpartum hemorrhage.Based on the research and guidelines of preeclampsia and postpartum hemorrhage in recent years,this paper analyzes the influencing factors of preeclampsia on postpartum hemorrhage,and provides new ideas for clinical reduction of postpartum hemorrhage.

Predictions of bulk velocity for open channel flow through submerged vegetation

Vegetation is of great significance in river ecosystems in terms of hydrodynamics,water environment and ecology.The question of how to predict the bulk velocity in channel flow through submerged vegetation is currently a hot topic in hydraulics research.The present study addresses this question.The various formulae used for bulk velocity estimation in previous work were reviewed and compared.The main novelty of this paper is that a new expression of friction factor is proposed as a function of two dimensionless factors,and the number of tuning parameters is less than that in previous work.A comparison of measured and calculated data was conducted for flow through submerged rigid and flexible vegetation.The comparison showed that the proposed new model can make more accurate predictions than previous models.It is envisaged that the proposed formulation can be usefully employed in eco-hydraulics predictions.

Dispersion features of pollutants in a compound channel with vegetated floodplains

The planting of the vegetation on the floodplain helps the ecological restoration,which is the main form of the river’s ecological corridor.Therefore,the current research of the river dynamics focuses on the water movement under a compound channel with the vegetated floodplains.Two simulated vegetation species are selected in this paper for the flume simulation experiments of the floodplain vegetation,and the compound channel is divided into three subregions in the transverse direction.The Navier-Stokes equation and the eddy viscosity theory are applied to obtain the transverse distribution of the depth-averaged velocity and the results agree well with the experimental data.This paper proposes a new method based on the analytical solution of the flow velocity distribution to calculate the average flow velocity in each section.Calculation results can effectively simulate the average flow velocity of the measured sections.The description of the pollutant transport processes in a moving stream requires a refined determination of the dispersion coefficients in the compound channel.The process of the pollutant concentrations in each zone and the reasons for their occurrence are elucidated on the basis of the experimental results.Simultaneously,the measured values of the longitudinal dispersion coefficients are obtained by the“routing procedure,”and a two-zone model of the pollutant dispersion is constructed on the basis of the hydrodynamic study.The prediction method for the longitudinal dispersion coefficients is also presented.Applying the predicted and measured section average flow velocities to the two-zone model to predict the longitudinal dispersion coefficient,and the average relative errors are only 4.17%,7.15%,respectively.This result indicates that the two-zone model can effectively predict the longitudinal dispersion coefficients.The calculation methods for the longitudinal dispersion coefficients from—various studies are compared.The results reveal that the predicted values of these calculation methods are all larger than the measured values,indicating that the vegetation has a considerable influence on the dispersion process.This study comprehensively shows the dispersion features of the pollutants and provides a theoretical basis for the planning and the design of the vegetated ecological corridors.

Structural changes of a bacteriophage upon DNA packaging and maturation

Dear Editor,Tailed,double-stranded DNA(dsDNA)bacteriophages,which belong to the order of Caudovirales,have a tail attached to a pentameric vertex of the icosahedral capsid shell(head)through a 12-fold portal(Johnson and Chiu,2007).The phages package genomic dsDNA into a round procapsid using the portal in complex with an ATP-dependent terminase complex as the motor.During packaging,the procapsid shell expands to a more angular intermediate to match the size of the viral genome(Guo et al.,2014).When the phage head is full,the portal detects internal pressure and conveys a signal from the inner capsid to the exterior,which triggers a sequence of events-the terminase complex cleaving mature DNA genome from a multi-genome concatemer,the release of the terminase complex from the portal,and the attachment of the tail complex-in the completion of phage assembly(Lander et al.,2006;Johnson and Chiu,2007).At the beginning of phage infection,the tail is responsible for receptor recognition,and the portal and tail act as a tunnel for DNA delivery into the host cytoplasm(Johnson and Chiu,2007).These mechanisms of DNA packaging and ejection may also be conserved in many other DNA viruses,including herpesvirus(Wang et al.,2020;Yang et al.,2020).

Short-term tunnel-settlement prediction based on Bayesian wavelet:a probability analysis method

As urbanization accelerates,the metro has become an important means of transportation.Considering the safety problems caused by metro construction,ground settlement needs to be monitored and predicted regularly,especially when a new metro line crosses an existing one.In this paper,we propose a settlement-probability prediction model with a Bayesian emulator(BE)based on the Gaussian prior(GP),that is,a GPBE.In addition,considering the distortion characteristics of monitoring data,the data is denoised using wavelet decomposition(WD),so the final prediction model is WD-GPBE.In particular,the effects of different prediction ratios and moving windows on prediction performance are explored,and the optimal number of moving windows is determined.In addition,the predicted value for GPBE based on the original data is compared with the predicted value for WD-GPBE based on the denoised data.One year of settlement-monitoring data collected by a structural health monitoring(SHM)system installed on the Nanjing Metro is used to demonstrate the effectiveness of WDGPBE and GPBE for predicting settlement.

民营企业“去家族化”能促进企业创新吗

随着"创一代"的衰老,家族企业面临严峻的传承与创新问题,传统的单一管理模式难以适应新时代的发展。以中国上市公司为样本,本文检验民营企业"去家族化"对创新的影响,并结合职业经理人市场,进一步探讨了职业经理人对企业创新的影响机制。研究发现,民营企业"去家族化"水平越高,公司越倾向于进行更多的研发投入,从而产出更多的研发成果。这说明"去家族化"促进了企业创新,即职业经理人对企业创新具有正向的推动作用。我们进一步发现,当职业经理人面临更激烈的市场竞争时,企业产出更多的研发成果,间接说明职业经理人为提高市场竞争力而推动企业创新。此外,本文的研究还表明,职业经理人对声誉的重视是其推动企业创新的重要因素。

Archaeal community structure along a gradient of petroleum contamination in saline-alkali soil

The response of archaeal communities to petroleum contamination in saline-alkali soil was characterized by analyses of three soil samples with different total petroleum hydrocarbon concentrations.Through the construction and screening of 16S rRNA gene clone libraries based on DNA extracts from these soils,nine distinct phylogenetic groups were identified.Statistical analyses showed that the distribution of archaeal community structures differ significantly along the gradient of petroleum contamination in these three saline- alkali soils.Five phylogenetic groups were dominant in the control soil,two of which were also abundant in the lightly contaminated soil.Four phylogenetic groups were dominant in heavily contaminated soil,one of which was also abundant in the lightly contaminated soil.The halophilic genus of Haloferax and the haloalkaliphilic genus of Natronomonas were more abundant in heavily contaminated soil.These results suggested that the genera of Haloferax and Natronomonas may have a role in the natural attenuation of petroleum- contaminated saline-alkali soil.

Intercluster aurophilicity-driven aggregation lighting circularly polarized luminescence of chiral gold clusters

Herein,we prepared two novel pairs of enantiomeric gold cluster complexes,AU4PL4/Au4PD4 and(Au4L4)n/(Au4D4)n with atomic precision.In Au4PL4/Au4PD4,the discrete chiral Au4-based aggregation-induced emission(AIE)luminogens are separated by bulky substitutes.The corresponding aggregates are cyan-emitting with a photoluminescence quantum yield(PLQY)of 14.4%.Upon decreasing the size of the substituents,these chiral Au4 clusters are strung together by inter-cluster Au-Au interactions,which cause a low-energy green emission from the aggregated(Au4L4)n/(Au4D4)n with a much higher PLQY of 41.4%and more intense circularly polarised photoluminescence(CPL)with a dissymmetry factor|gPL|of 7.0×10^−3.Using(Au4L4)n/(Au4D4)n,circularly polarised organic light-emitting diodes(CP-OLEDs)were for the first time fabricated with|gEL|=|gPL|.These findings signify that inter-cluster metallophilic interactions are a new and important type of driving force for AIE and crystallization-induced emission(CIE),suggesting great potential of CPL-active metal clusters in CP-OLEDs.