Promoting normal childbirth:Research status and application of upright positions in the second stage of labour

In recent years,more and more attention has been paid to normal childbirth.The World Health Organization(WHO),International Confederation of Midwives(ICM),Chinese Maternal and Child Health Association(CMCHA)have actively advocated normal childbirth[[1],[2],[3]].It is proved that normal childbirth can improve birth outcomes.

Does Postoperative Rehabilitation for Radical Cystectomy Call for Enhanced Recovery after Surgery?A Systematic Review and Metaanalysis

The aim of this review was to systematically compare the outcomes of enhanced recovery after surgery(ERAS)with standard care(SC)after radical cystectomy.We performed a systematic search of PubMed,Ovid?Web of Science,and the Cochrane Library to identify studies published until September 2017 which involved a comparison of ERAS and SC.A meta-analysis was performed to assess the outcomes of ERAS versus SC.Sixteen studies including 8 prospective and 8 retrospective trials met the eligibility criteria.A total of 2100 participants were assigned to ERAS(1258 cases)or SC(842 cases).The time to first flatus passage[WMD=-0.95 days,95%Cl(-1.50,-0.41),P=0.0006],time until return to a regular diet[WMD=-2.15 days,95%Cl(-2.86,—1.45),P<0.00001]and the length of hospital stay[WMD=-3.75 days,95%Cl(-5.13,-2.36),P<0.00001]were significantly shorter,and the incidence of postoperative complications[OR=0.60,95%Cl(0.44,0.83),P=0.002],especially postoperative paralytic ileus[OR=0.43,95%Cl(0.30,0.62),P<0.00001]and cardiovascular complications[OR=0.28,95%Cl(0.09,0.90),P=0.03]was significantly lower in the ERAS group than those in the SC group.This meta-analysis demonstrated that ERAS was associated with a shorter time to first flatus passage,return of bowel fimction,and the length of hospital stay than SC in patients undergoing radical cystectomy,as well as a lower rate of postoperative complications,especially paralytic ileus and cardiovascular complications.

A review and comparison of common maternal positions during the second-stage of labor

The second-stage of labor is the most stressful part of childbirth process and the proper maternal position during this period is paramount for women's safe vaginal birth.Midwives play a pivotal role in managing maternal positions during the second-stage of labor.However,there is limited evidence to support an ideal maternal position during the second-stage of labor.Further,the difference between different maternal positions might not be apparent.This paper aims to review and compare the benefits and risks of common maternal positions during the second-stage of labor,thereby to provide midwives evidence-based practical guidelines.

Nicotine dependence in community-dwelling Chinese patients with schizophrenia

Background Smoking is a serious public health problem. Patients with schizophrenia usually have a higher prevalence of smoking than the general population, but the level of nicotine dependence is seldom studied, especially for patients living in the communities. Aims This study aimed to examine the level of nicotine dependence in Chinese community-dwelling patients with schizophrenia and explored its associated sociodemographic and clinical factors. Methods A total of 621 patients with schizophrenia treated in the primary care centres of Guangzhou were consecutively recruited. The level of nicotine dependence was assessed with the Chinese version of the Fagerstrom Test for Nicotine Dependence (FTND). Results 148 patients with schizophrenia were current smokers, and the mean (SD) score of FTND was 5.06 (2.55) for all the current smokers. The prevalence of nicotine addiction was 48.0%(95% Cl: 40.0%-56.0%) in patients with current smoking. The patients with schizophrenia had a significantly higher level of nicotine dependence than the Chinese general population. Multiple linear regression analysis revealed that male gender, being unemployed, having a family history of psychiatric disorders, having major medical conditions, first illness episode and less severe positive symptoms were significantly associated with a higher level of nicotine dependence. Conclusion Community-dwelling patients with schizophrenia in China, especially male patients, had a higher level of nicotine dependence than the general population.

高速列车运行控制系统车载子系统故障预测方法研究

列车运行控制系统是高速列车信息控制系统的"神经中枢",其结构复杂、组件繁多,其中,车载子系统是列车运行控制系统的核心组成部分,是保证行车安全、提高运行效率的关键.目前,车载子系统的故障数据处理方式仍以人工处理实现故障定位为主,尚未深入到系统故障机理层面,无法实现有效的故障预测.本文分析了车载子系统的结构及系统故障处置现状,总结了现存的主要问题,结合车载子系统结构及各模块性能参数,提出了基于贝叶斯网络(Bayesian network, BN)的系统级故障预测模型构建方法.利用实际系统现场运行数据,采用基于贝叶斯网络的方法进行故障预测,分别在20, 200, 2000,20000组数据条件下实施了验证,故障预测准确率分别为5%, 27%, 92%, 96.3%,在2000组数据条件下同时对隐马尔科夫模型(hidden Markov model, HMM)、神经网络(neural network, NN)与本文所提出的方法进行了对比,预测结果验证了贝叶斯网络在系统级故障预测方面的显著优势.

Optimization of variables for maximizing efficacy and efficiency in aerial spray application to cotton using unmanned aerial systems

Aerial spraying can support efficient defoliation without crop contact.With the recent introduction to unmanned aerial system(UAS)for aerial spraying in China,there is a need to determine the optimum application variables to achieve high efficacy and efficiency with low costs.The present research involved field studies across two annual cotton production seasons in North Xinjiang,China.Four factors,including volume rate(A),tank mix including spray adjuvants(B),flight altitude(C),flight speed(D)and three levels of L9(3^(4))orthogonal arrays were carried out to optimize the application parameters for three types of UASs.These included different numbers of rotors as follows:four-rotors,six-rotors and eight-rotors.Spray coverage,distribution uniformity(coefficient of variation(CV)of droplet coverage),rates of cotton defoliation and boll opening,application efficiency and cost were measured and assessed.Results showed that:(1)the rates of defoliation and boll opening by aerial cotton defoliant application could meet the requirement of cotton mechanized harvesting;(2)the optimal scenario for the three UASs was A_(3)B_(2)C_(1)D_(3),Volume rate(A3):48 L/hm^(2);Tank mix and concentration(B_(2)):(Tuotulong 225+Sujie 750+Ethephon 2250)mL/hm^(2),Flight altitude(C_(1)):1.5 m,and Flight speeds(D_(3))for unmanned helicopters with four-rotors,six-rotors and eight-rotors were 3.12 m/s,2.51 m/s and 3.76 m/s,respectively.These results can provide guidance for cotton defoliant aerial spraying in China using UAS.

Design and anti-sway performance testing of pesticide tanks in spraying UAVs

Anti-sway performance is one of the most important factors that affect the stability of unmanned aerial vehicles(UAVs).In this study,an anti-sway performance testing method and an evaluation formula for pesticide tanks were developed,which could facilitate the design and application of pesticide tank.The detection device mainly comprises a testing stand,a mounting and testing part,and a driving and control part.In the testing method,P(maximum pressure)measured by a barometer and t(fluctuation recovery time)measured by a high-speed camera were used as evaluation indexes.With the aim to determine the optimal position of the pressure detection device and the optimal filling ratio,four representative pesticide tanks were involved in this study.The results showed that the optimal position of the pressure detection device was at the middle position on the tank wall,halfway up from the bottom,and the optimal filling ratio was 0.8.Using P and t as evaluation indexes,a comprehensive evaluation formula was developed based on these tests:S=0.7Pi+0.3ti.Anti-sway performance of pesticide tanks was evaluated by a comprehensive score.A disk pesticide tank with a baffle was determined to be the best among the four types of pesticide tanks,showing a score of 1.The scores of the other three pesticide tanks were 0.500,0.428 and 0.612,respectively.These results indicated that the baffle structure in the pesticide tank and the radian design of the tank wall can effectively improve the anti-sway performance of a pesticide tank.The proposed detection device and test method are simpler and more intuitive compared to other approaches in evaluating the anti-sway performance of pesticide tanks in spraying UAVs,and they can be used as a reference to guide the design of pesticide tanks and the stability evaluation of spraying UAVs.

Optimization of aviation adjuvants based on wettability analysis for insecticide application on maize using UAV

Adjuvants can increase the control efficacy of diseases and insect pests by changing the physico-chemical properties of pesticides.Most of the aviation spray adjuvants are versions of ground adjuvants.Maize insecticide sprays with unmanned aerial vehicles(UAV),have problems such as relatively low droplet deposition rate and poor wettability.Hence,wettability research and optimization tests for aviation spray adjuvants are needed.The present study screened 12 spray adjuvants using physico-chemical property experiments.The adjuvants were applied to improve the droplet deposition and control efficacy in maize borers controlling by UAV.The selected spray adjuvants were Po2(a hyperbranched polymer adjuvant)and VO3(a vegetable oil adjuvant).Results showed that,(1)When Po2 was added in water-dispersible granules(WGs)at volume rate of 12 L/hm2,the dynamic surface tension(DST)of WGs was decreased by 37.41%,and the maize leaves were covered by droplets 100%,the droplet deposition was increased by 104%and maize borer control was increased by 46%;(2)VO3 decreased the surface tension of ultra-low-volume(ULV)formulation by 12.02%and the maize leaves were covered by droplets 100%.The effect of VO3 on improving the droplet deposition and control efficacy at 12 L/hm2 with ULV was not significant.Thus,the addition of aviation spray adjuvant to improve the wettability of WGs significantly improved the droplet deposition and control efficacy but it had no significant effect on the ULV formulation.

Laser tracking leader-follower automatic cooperative navigation system for UAVs

Currently,small payload and short endurance are the main problems of a single UAV in agricultural applications,especially in large-scale farmland.It is one of the important methods to solve the above problems of UAVs by improving operation efficiency through multi-UAV cooperative navigation.This study proposed a laser tracking leader-follower automatic cooperative navigation system for multi-UAVs.The leader in the cluster fires a laser beam to irradiate the follower,and the follower performs a visual tracking flight according to the light spot at the relative position of the laser tracking device.Based on the existing kernel correlation filter(KCF)tracking algorithm,an improved KCF real-time spot tracking method was proposed.Compared with the traditional KCF tracking algorithm,the recognition and tracking rate of the optimized algorithm was increased from 70%to 95%in indoor environment,and was increased from 20%to 90%in outdoor environment.The navigation control method was studied from two aspects:the distance coordinate transformation model based on micro-gyroscope and navigation control strategy.The error of spot position was reduced from the maximum(3.12,−3.66)cm to(0.14,0.12)cm by correcting the deviation distance of the spot at different angles through a coordinate correction algorithm.An image coordinate conversion model was established for a complementary metal-oxide-semiconductor(CMOS)camera and laser receiving device at different mounting distances.The laser receiving device was divided into four regions,S0-S3,and the speed of the four regions is calculated using an uncontrollable discrete Kalman filter.The outdoor flight experiments of two UAVs were carried out outdoors using this system.The experiment results show that the average flight error of the two UAVs on the X-axis is 5.2 cm,and the coefficient of variation is 0.0181.The average flight error on the Z-axis is 7.3 cm,and the coefficient of variation is 0.0414.This study demonstrated the possibility and adaptability of the developed system to achieve multi-UAVs cooperative navigation.