Phylogeography and diversification of Oriental weaverbirds(Ploceus spp.):A gradual increase of eurytopy

Weaverbirds are a speciose group of colorful passerines inhabiting the Old World Tropics.Nevertheless,the Oriental weaverbirds(Ploceus spp.),widespread across southern Asia,are much less diverse and restricted to a few ecological niches compared to their African counterpart.To investigate their phylogeography,we retrieved 101 samples of Baya Weaver(P.philippinus),Streaked Weaver(P.manyar),Black-Throated Weaver(P.benghalensis)and Asian Golden Weaver(P.hypoxanthus)along with GenBank sequences of Finn's Weaver(P.megarhynchus).We reconstructed the first molecular phylogeny based on a dataset consisting of both mitochondrial and nuclear genes,dating the most recent common ancestor of Oriental Ploceus to~11 mya.Subsequent speciation appears to have been a combination of divergence within the Indian subcontinent and dispersal across a barrier situated between the Indian subcontinent and the Indochinese region,which provided habitats with a varying degree of isolations and ultimately promoted divergences in allopatry.Two descendants of the earliest nodes,P.megarhynchus and P.hypoxanthus,are both rare and local,often found near large river systems,which perhaps reflects niche conservatism and a lack of adaptive potential.The three smaller species are all widespread,common and less habitat specific.The most recent divergence,between western and eastern P.philippinus populations,is supported by both phylogenetic and morphological evidence,pointing toward limited gene flow between them.However,a zone of intergradation may exist in Myanmar and Brahmaputra flood plains,thus preventing a recommendation for species level recognition without further study.

大型立式蜗壳离心泵主要参数选择及模型试验

针对泵站扬程变幅大、泥沙含量大的运行环境,研究了立式蜗壳离心泵的水力特性,为水泵参数选取提供依据。结合重庆市渝西水资源配置工程金刚沱泵站工程特性及类似工程经验,对水泵参数的选择进行了优化,同时为验证水泵模型的水力特性,进行了水泵模型试验。试验结果表明:水泵模型效率、压力脉动、空化特性等各项指标均满足要求,水泵在中高扬程段装置空化系数裕量充足,低扬程段可以保证稳定运行,预计水泵将拥有良好的水力性能。研究成果说明水泵参数选择合理,可为同类型水泵的选型设计及水力开发提供参考。

Preliminary Discussion on the Refinement Mesh Generation for Adaptive Analysis

In recent years, due to the rapid development of computer hardware and the urgent need of complex engineering problems, great support has been provided in the related fields of unstructured mesh generation. A large number of research results show that the adaptive analysis is an effective way to improve the efficiency and precision of the numerical calculation. The reliable error estimation and the powerful mesh generation are two key problems in the process of adaptive numerical analysis. H-type refinement strategy adding the new nodes in the high error area, gradually refines the mesh to reduce the size of the element to achieve the purpose of mesh adaptation;this strategy is simple, intuitive and easy to program. Although the calculation accuracy of unstructured triangle and tetrahedron elements is not high, these elements are suitable for discretization of any complex problem domain, and have a wider range of application in academic and engineering fields.

Diagnostic accuracy of transient elastography (Fibro Scan) in detection of esophageal varices in patients with cirrhosis: A meta-analysis

AIM To investigate the diagnostic accuracy of Fibro Scan(FS) in detecting esophageal varices(EV) in cirrhotic patients.METHODS Through a systemic literature search of multiple databases, we reviewed 15 studies using endoscopy as a reference standard, with the data necessary to calculate pooled sensitivity(SEN) and specificity(SPE), positive and negative LR, diagnostic odds ratio(DOR) and area under receiver operating characteristics(AUROC). The quality of the studies was rated by the Quality Assessment of Diagnostic Accuracy studies-2 tool. Clinical utility of FS for EV was evaluated by a Fagan plot. Heterogeneity was explored using meta-regression and subgroup analysis. All statistical analyses were conducted via Stata12.0, MetaD isc1.4 and RevM an5.RESULTS In 15 studies(n = 2697), FS detected the presence of EV with the summary sensitivities of 84%(95%CI: 81.0%-86.0%), specificities of 62%(95%CI: 58.0%-66.0%), a positive LR of 2.3(95%CI: 1.81-2.94), a negative LR of 0.26(95%CI: 0.19-0.35), a DOR of 9.33(95%CI: 5.84-14.92) and an AUROC of 0.8262. FS diagnosed the presence of large EV with the pooled SEN of 0.78(95%CI: 75.0%-81.0%), SPE of 0.76(95%CI: 73.0%-78.0%), a positive and negative LR of 3.03(95%CI: 2.38-3.86) and 0.30(95%CI: 0.23-0.39) respectively, a summary diagnostic OR of 10.69(95%CI: 6.81-16.78), and an AUROC of 0.8321. A meta-regression and subgroup analysis indicated different etiology could serve as a potential source of heterogeneity in the diagnosis of the presence of EV group. A Deek's funnel plot suggested a low probability for publication bias.CONCLUSION Using FS to measure liver stiffness cannot provide high accuracy for the size of EV due to the various cutoff and different etiologies. These limitations preclude widespread use in clinical practice at this time; therefore, the results should be interpreted cautiously given its SEN and SPE.

Magnetic Array Assisted Triboelectric Nanogenerator Sensor for Real‑Time Gesture Interaction

In human-machine interaction,robotic hands are useful in many scenarios.To operate robotic hands via gestures instead of handles will greatly improve the convenience and intuition of human-machine interaction.Here,we present a magnetic array assisted sliding triboelectric sensor for achieving a real-time gesture interaction between a human hand and robotic hand.With a finger’s traction movement of flexion or extension,the sensor can induce positive/negative pulse signals.Through counting the pulses in unit time,the degree,speed,and direction of finger motion can be judged in realtime.The magnetic array plays an important role in generating the quantifiable pulses.The designed two parts of magnetic array can transform sliding motion into contact-separation and constrain the sliding pathway,respectively,thus improve the durability,low speed signal amplitude,and stability of the system.This direct quantization approach and optimization of wearable gesture sensor provide a new strategy for achieving a natural,intuitive,and real-time human-robotic interaction.

水电站机组制动供气系统设备的优化研究

我国水电站机电设计手册上的一次制动耗气量公式,计算结果偏大,而机组一次制动的实际耗气量远远低于手册上的理论计算值,用连续给气方式用于供气设备的选型存在很多弊端,如空压机启停频繁导致的润滑油乳化、储气罐容积和空压机排气量过大导致设备浪费、储气罐和空压机之间不匹配等。针对这个问题,采用体积法计算一次制动耗气量,给出了耗气量随机组单机容量的变化范围;优化了储气罐容积和空压机排气量的计算公式,归纳出两者之间的合理匹配关系;总结出大中型抽水蓄能电站一次制动耗气量取值范围的推荐值。结合具体算例分析,验证新方法和新公式具有科学性和实用性。

西藏地区某水电站水轮机主要参数选择及模型验收试验

针对西藏地区某水电站海拔高、气温低、泥沙含量较大的特点,结合电站工程特性及类似工程实际经验,对水轮机设计参数的选择进行了探讨,并将上述水轮机参数提供给机组制造厂家用以开发水轮机模型转轮。为验证水轮机参数的合理性及水轮机模型的水力特性,进行了水轮机模型验收试验,试验结果表明水轮机参数选择合理先进,开发的水轮机模型转轮具有良好的重复性,模型水轮机的各项水力性能指标均满足合同要求,上述成果可为同类型水轮机的选型设计提供参考。

Structural Design and Performance Analysis of a Deep-Water Ball Joint Seal

To overcome the current difficulties of high-precision machining and the high manufacturing and maintenance costs of spherical seals for deep-water drilling ball joints,a new spherical seal technique is proposed in this paper.The spherical seal is mainly composed of silicone rubber and polytetrafluoroethylene(PTFE).Rational structural design makes the seal independent from the ball and other components,making it easy to replace if leakage occurs at its surface.PTFE can elastically deform over a certain deformation range,which guarantees that two sealing surfaces fit tightly together.O-Ring and PTFE elasticity makes up for any lack of accuracy during spherical machining and decreases the machining precision requirements for spherical surfaces.Using a finite element technique and nonlinear theory,the performance of the spherical seal under the influence of various factors is determined.The results show that the spherical seal designed in this paper exhibits excellent sealing performance under lowtemperature and high-pressure conditions.The spherical seal,a combination of an O-ring and PTFE,has the advantages of cheap manufacturing and maintenance costs and excellent sealing performance.

西藏DG水电站环保智能排水系统设计

西藏地区水电站所处环境的特殊性,导致其设计过程远远复杂于内地,而排水系统作为厂房内重要的辅助设备系统,其成功与否影响着电站的安全稳定运行。文章介绍了西藏DG水电站厂内排水系统的设计,并简述了设备布置的特点。该电站排水系统将无油渗漏排水系统和含油污水排水系统分开设置,响应了环保需求;同时,通过设置防冻排水管以及管网在线监测系统,保证了设备和管路的安全。该电站排水系统设计充分结合了当地气候环境的特点,配置安全可靠合理,可为同类型电站的选型设计提供参考。

The Accelerated Thermo-Oxidative Aging Characteristics of Wood Fiber/Polycaprolactone Composite:Effect of Temperature,Humidity and Time

This study investigated the characteristics of wood fiber/polycaprolactone composite after an artificial accelerated thermo-oxidative aging treatment.The effect of time,temperature and humidity during the treatment on their mechanical,chemical and morphology properties were evaluated.The composite was prepared from melted wood fibers and modified polycaprolactone by a molding process.A temperature and humidity controllable test chamber was used for the thermo-oxidative aging of the composite.The thermo-oxidative aging caused surface of the composite to be much more rougher and even a few cracks and holes appeared on it.According to the spectra of Fourier Transform Infrared(FTIR)and Gel Permeation Chromatography(GPC),C=O in the molecular chain of polycaprolactone was hydrolyzed and C–O was broken after the aging treatment,which resulted in a reduction in average molecular weight of the composite.Moreover,results showed that the mechanical strength decreased a lot with the increase in time,temperature and humidity,and the effect of temperature and humidity was more significant compared with that of time.Controlling the temperature and humidity during thermo-oxidative aging treatment could accelerate the aging of composite,which provided a quick and effective method for evaluating the aging resistance of the composite.

Herbal medicine in the treatment of COVID-19 based on the gut-lung axis

Respiratory symptoms are most commonly experienced by patients in the early stages of novel coronavirus disease 2019 (COVID-19). However, with a better understanding of COVID-19, gastrointestinal symptoms such as diarrhea, nausea, and vomiting haveattracted increasing attention. The gastrointestinal tract may be a target organ of severe acute respiratory syndrome coronavirus2 (SARS-CoV-2) infection. The intestinal microecological balance is a crucial factor for homeostasis, including immunity andinflammation, which are closely related to COVID-19. Herbal medicine can restore intestinal function and regulate the gut florastructure. Herbal medicine has a long history of treating lung diseases from the perspective of the intestine, which is called thegut-lung axis. The physiological activities of guts and lungs influence each other through intestinal flora, microflora metabolites,and mucosal immunity. Microecological modulators are included in the diagnosis and treatment protocols for COVID-19. Inthis review, we demonstrate the relationship between COVID-19 and the gut, gut-lung axis, and the role of herbal medicine intreating respiratory diseases originating from the intestinal tract. It is expected that the significance of herbal medicine in treatingrespiratory diseases from the perspective of the intestinal tract could lead to new ideas and methods for treatment.

无人机目标追踪系统设计与实现

随着无人机技术的逐渐成熟,无人机也越来越贴合人们的生活。四轴无人飞行器因为小巧灵活深受人们的喜爱,但现实生活中无人机的操控往往需要花费大量的学习时间成本,同时四轴无人机在动态场景中检测和跟踪非常困难。基于此,设计一套基于DeepSORT目标跟踪算法和YOLO-V3目标检测算法的无人机目标追踪系统,实现目标追踪、轨迹推演、手势控制功能,让人们可通过手势来操控无人机,实现目标追踪等复杂繁琐的任务。

Shear-thickening behavior of Fe-ZSM5 zeolite slurry and its removal with alumina/boehmites

A cryogenic scanning electron microscopy（cryo-SEM） technique was used to explore the shear-thickening behavior of Fe-ZSM5 zeolite pastes and to discover its underlying mechanism. Bare Fe-ZSM5 zeolite samples were found to contain agglomerations, which may break the flow of the pastes and cause shear-thickening behaviors. However, the shear-thickening behaviors can be eliminated by the addition of halloysite and various boehmites because of improved particle packing. Furthermore, compared with pure Fe-ZSM5 zeolite samples and its composite samples with halloysite, the samples with boehmite（Pural SB or Disperal） additions exhibited network structures in their cryo-SEM images; these structures could facilitate the storage and release of flow water, smooth paste flow, and avoid shear-thickening. By contrast, another boehmite（Versal 250） formed agglomerations rather than network structures after being added to the Fe-ZSM5 zeolite paste and resulted in shear-thickening behavior. Consequently, the results suggest that these network structures play key roles in eliminating the shear-thickening behavior.

Allyl Glycidyl Ether-modified Animal Glue Binder for Improved Water Resistance and Bonding Strength in Sand Casting

This paper aims to develop a modified animal glue sand binder for foundry casting with improved water resistance and bonding strength.An efficient method is reported by using sodium hydroxide as the catalyst to improve the operability of animal glue binder and allyl glycidyl ether as the modifier to improve the water resistance and bonding strength.Sand specimens prepared using allyl glycidyl ether-modified animal glue binder were cured by compressed air at room temperature.The proposed method saves energy and is environmentally friendly and inexpensive.Compared with unmodified animal glue binder,standard dog bone sand specimens with allyl glycidyl ether-modified animal glue binder had higher tensile strength of 2.58 MPa,flowability of 1.95 g,better water resistance(a lower decrease in tensile strength at 25°C and relative humidity of 60%),and good collapsibility.This allyl glycidyl ether-modified animal glue binder is suitable for practical application in the foundry industry.

Research and Practice of Telecommunication User Rating Method Based on Machine Learning

The machine learning model has advantages in multi-category credit rating classification.It can replace discriminant analysis based on statistical methods,greatly helping credit rating reduce human interference and improve rating efficiency.Therefore,we use a variety of machine learning algorithms to study the credit rating of telecom users.This paper conducts data understanding and preprocessing on Operator Telecom user data,and matches the user’s characteristics and tags based on the time sliding window method.In order to deal with the deviation caused by the imbalance of multi-category data,the SMOTE oversampling method is used to balance the data.Using the Removing features with low variance method and packaging method for feature selection,then the basic models are established.The empirical results of the model show that the Random Forest and XGBOOST ensemble models are better than the single models such as Bayes,SVM,KNN,and Decision Tree.The performance of Decision Tree in single models is better.Therefore,Random Forest,XGBOOST and Decision Tree models were selected to debug the hyper parameters to achieve model optimization.Based on the optimized model,the accuracy,recall,precision,confusion matrix and other indicators are evaluated,and it is concluded that lowlevel recognition is more accurate than high-level recognition and fewer misjudgments.Comparing the evaluation indicators of each level of different models,it is found that the integrated model performs better,indicating that Random Forest and XGBOOST are more suitable for solving the problem of telecommunications user rating.For this reason,this article proposes an implementation plan based on Random Forest and XGBOOST algorithm and model for the problem of telecommunications user rating.

Churn Prediction Model of Telecom Users Based on XGBoost

As the cost of accessing a telecom operator’s network continues to decrease,user churn after arrears occurred repeatedly,which has brought huge economic losses to operators and reminded them that it is significant to identify users who are likely to churn in advance.Machine learning can form a series of judgment rules by summarizing a large amount of data,and telecom user data naturally has the advantage of user scale,which can provide data support for learning algorithms.XGBoost is an improved gradient boosting algorithm,and in this paper,we explore how to use the algorithm to train an efficient model and use this model one month in advance to predict whether users will churn.Our work is mainly divided into two aspects:(1)By completing data exploration,feature engineering and data preprocessing,we obtained a data set that can be used to train a prediction model and features that can effectively predict user churn.And using these features and data sets,two prediction models were trained based on Random Forest and XGBoost.(2)According to the business needs of telecom operators,we continuously evaluated and optimized these models.And by comparing the test results of the two models,we proved that the XGBoost model performs better for the precision and recall of user churn.

The Effects of Nutritional Interventions on Energy Metabolism

Energy metabolism is vital to the body's metabolic processes.A key player in the production of ATP,mitochondria directly affect energy homeostasis.Mitochondrial dysfunction is the cause of many diseases.Many reports have suggested that nutritional interventions can play a protective role against the development of mitochondrial dysfunction or in ameliorating existing dysfunction,such as by improving energy metabolism.This review focuses on the impact of different nutritional interventions on energy metabolism.

大数据在网格化社会治理中的法律保障问题研究

网格化社会治理就是把基层社区划分成若干责任网格,将人、地、物、事、组织全部纳入具体网格的一种治理模式。网格化社会治理过程中会产生大量记录着行政区域自然、政治、经济、文化、社会等方面历史与现状的数据。大数据的应用有助于提高社会治理的智能化、专业化水平,但与此同时,大数据本身具有一定的法律风险,本文从隐私权和储存过程中的法律风险防控角度探讨大数据在网格化社会治理中的法律保障问题。

Yangtze River Delta Aerosol liquid water in PM_(2.5)and its roles in secondary aerosol formation at a regional site of Yangtze River Delta

Aerosol liquid water content(ALWC)plays an important role in secondary aerosol formation.In this study,a whole year field campaign was conducted at Shanxi in north Zhejiang Province during 2021.ALWC estimated by ISORROPIA-Ⅱ was then investigated to explore its characteristics and relationship with secondary aerosols.ALWC exhibited a highest value in spring(66.38μg/m^(3)),followed by winter(45.08μg/m^(3)),summer(41.64μg/m^(3)),and autumn(35.01μg/m^(3)),respectively.It was supposed that the secondary inorganic aerosols(SIA)were facilitated under higher ALWC conditions(RH>80%),while the secondary organic species tended to form under lower ALWC levels.Higher RH(>80%)promoted the NO_(3)^(-)formation via gas-particle partitioning,while SO_(4)^(2-)was generated at a relative lower RH(>50%).The ALWC was more sensitive to NO_(3)^(-)(R=0.94)than SO_(4)^(2-)(R=0.90).Thus,the self-amplifying processes between the ALWC and SIA enhanced the particle mass growth.The sensitivity of ALWC and OX(NO_(2)+O_(3))to secondary organic carbon(SOC)varied in different seasons at Shanxi,more sensitive to aqueous-phase reactions(daytime R=0.84;nighttime R=0.54)than photochemical oxidation(daytime R=0.23;nighttime R=0.41)in wintertime with a high level of OX(daytime:130-140μg/m^(3);nighttime:100-140μg/m^(3)).The self-amplifying process of ALWC and SIA and the aqueous-phase formation of SOC will enhance aerosol formation,contributing to air pollution and reduction of visibility.

Impact factors and pathways of halonitromethanes formation from aspartic acid during LED-UV_(265)/chlorine disinfection

Light emitting diode (LED-UV)/chlorine disinfection can replace UV/chlorine disinfection in wastewater treatment plants and water supply plants. Halonitromethanes (HNMs) are a class of novel nitrogenous disinfection by-products, which are characterized by higher cytotoxicity and genotoxicity than regulated disinfection by-products. Herein, the impact factors and pathways of HNMs formation from aspartic acid (ASP) were investigated during LED-UV_(265)/chlorine disinfection. The results showed that three types of chlorinated-HNMs (Cl-HNMs) were found during LED-UV265/chlorine disinfection, and their concentrations increased first and then declined as the reaction progressed. Cl-HNMs yields increased with increasing LED-UV_(265) intensity, free chlorine dosage, and ASP concentration, which declined with increasing pH (6.0–8.0). Meantime, the important impact of the coexisting ions contained in water matrices on HNMs formation from ASP was observed during LED-UV_(265)/chlorine disinfection. It was found that copper ions (Cu^(2+)) promoted Cl-HNMs formation. Furthermore, when bromide (Br–) appeared during LED-UV265/chlorine disinfection, nine types of HNMs were detected simultaneously. Moreover, Br– not only converted Cl-HNMs toward brominated (chlorinated)-HNMs and brominated-HNMs but also showed a marked effect on HNMs concentrations and species. Subsequently, the possible pathways of HNMs formation from ASP were proposed during LED-UV_(265)/chlorine disinfection. At last, it was proved that the formation trends of HNMs obtained in the real waters were similar to those in simulated waters. This work elaborated on the influence factors and pathways of HNMs formation, which is conducive to controlling the HNMs produced during LED-UV_(265)/chlorine disinfection.