Effect of various crop rotations on rice yield and nitrogen use efficiency in paddy–upland systems in southeastern China

To evaluate the effects of various rotation systems on rice grain yield and N use efficiency, a paddy–upland cropping experiment(2013–2016) was conducted in southeastern China. The experiment was designed using six different rice––winter crop rotations: rice–fallow(RF),rice–wheat(RW), rice–potato with rice straw mulch(RP), rice–green manure(Chinese milk vetch; RC–G), rice–oilseed rape(RO), and rice–green manure crop(oilseed rape with fresh straw incorporated into soil at flowering; RO–G) and three N rates, N0(0 kg N ha-1), N1(142.5 kg N ha-1), and N2(202.5 kg N ha-1). Average rice yields in the RF(5.93 t ha-1) rotation were significantly lower than those in the rotations with winter crops(7.20–7.48 t ha-1)under the N0 treatment, suggesting that incorporation of straw might be more effective for increasing soil N than winter fallow. The rice yield differences among the rotations varied by year with the N input. In general, the grain yields in the RP and RO–G rotations –were respectively 11.6–28.5% and 14.80–37.19% higher than those in the RF in plots with N applied. Increasing the N rate may have tended to minimize the average yield gap between the RF and the other rotations; the yield gaps were 18.55%, 4.14%, and 0.23% in N0, N1, and N2, respectively. However, the N recovery efficiency in the RF was significantly lower than that in other rotations, except for 2015 under both N1 and N2 rates, a finding that implies a large amount of chemical N loss. No significant differences in nitrogen agronomic efficiency(NAE) and physiological efficiency(NPE) were found between the rotations with legume(RC–G) and non–legume(RO and RW) winter crops, a result that may be due partly to straw incorporation. For this reason, we concluded that the return of straw could reduce differences in N use efficiency between rotations with and without legume crops. The degree of synchrony between the crop N demand and the N supply was evaluated by comparison of nitrogen balance degree(NBD) values. The NBD values in the RP and RW were significantly lower than those in the other rotations under both N1 and N2 rates. Thus,in view of the higher grain yield in the RP compared to the RW under the N1 rate, the RP rotation might be a promising practice with comparable grain yield and greater N use efficiency under reduced N input relative to the other rotations. The primary yield components of the RF and RP were identified as number of panicles m-2 and numbers of kernels panicle-1, respectively. The NAE and NPE were positively correlated with harvest index, possibly providing a useful indicator for evaluating N use efficiency.

Solar radiation-use characteristics of indica/japonica hybrid rice (Oryza sativa L.) in the late season in southeast China

New indica and japonica hybrid rice cultivars,such as the Yongyou series,provide farmers with very high yield potential.However,information on their canopy light capture and solar radiation use efficiency in the late season is limited.Field experiments were performed to compare the radiation-use parameters of four rice types:indica rice(IR),inbred japonica rice(IJR),hybrid japonica rice(HJR),and hybrid indica/japonica rice(HIJR),from 2016 to 2018 during the late season in Hangzhou,China.The grain yield,aboveground biomass,intercepted solar radiation(SI),and radiation-use efficiency(RUE)of the HIJR were on average respectively 13.4%–53.4%,14.3%–30.6%,7.6%–21.4%,and 8.2%–14.9%higher than those of the HJR,IJR,and IR.The leaf area index(LAI)of the HIJR was 18.2%–57.0%greater than that of the IJR and HJR at four growth stages,resulting in respectively 17.8%–38.5%and 10.7%–42.8%greater canopy light interception rates(LIR)and amount of intercepted solar radiation during the vegetative stage.The prolonged grain-filling stage also led to respectively 33.9%–52.6%and 30.5%–51.4%increases in amounts of incident and intercepted radiation for the HIJR relative to the IR during grain filling.These results indicate that the SI superiority of the HIJR was caused by canopy closure as rapid as that of the IR during the vegetative stage(greater LAI and canopy LIR during the growing season)and a grain-filling stage as long as that of the HJR.For grain-filling stage,differences in leaf Pn between HIJR,IR,and IJR were not significant,suggesting that the greater RUE of the HIJR(12.7%–52.8%higher)than that of the other rice types resulted from improved canopy architecture after flowering(FL).Principal components analysis(PCA)revealed that the superiority of the HIJR in terms of solar radiation use resulted from the greater canopy light capture capability of IR and the prolonged growth period(especially during grain filling)of japonica rice in the late growing season.

Effects of Different Nitrogen Treatments on N use Efficiency and Grain Yield of Mechanically-transplanted Hybrid Rice

In order to investigate effects of topdressing on grain yield and N use efficiency of mechanically-transplanted hybrid rice, this experiment was conducted with 2-line hybrid rice cultivars, Quanliangyou 1 and Quanliangyou 681 with 3 application levels of N fertilizer, N_0, N_1, N_2, respectively. The results showed that there were no significant differences in grain yields of the 2 varieties between treatments N_1 and N_2. It was indicated that N is not the factor which could limit grain yield within limited application levels of N fertilizer. High N fertilizer treatment could contribute to the formation of effective panicles and spikelets per panicle, but it could also lead to the decline in grain filling rate. It was suggested that lowering the amount of Nfertilizer could facilitate improvement of N-use efficiency.

Latest incidence and electrocardiographic predictors of atrial fibrillation:a prospective study from China

Background:China bears the biggest atrial fibrillation(AF)burden in the world.However,little is known about the incidence and predictors of AF.This study aimed to investigate the current incidence of AF and its electrocardiographic(ECG)predictors in general community individuals aged over 60 years in China.Methods:This was a prospective cohort study,recruiting subjects who were aged over 60 years and underwent annual health checkups from April to July 2015 in four community health centers in Songjiang District,Shanghai,China.The subjects were then followed up from 2015 to 2019 annually.Data on sociodemographic characteristics,medical history,and the resting 12-lead ECG were collected.Kaplan–Meier curve was used for showing the trends in AF incidence and calculating the predictors of AF.Associations of ECG abnormalities and AF incidence were examined using Cox proportional hazard models.Results:This study recruited 18,738 subjects,and 351(1.87%)developed AF.The overall incidence rate of AF was 5.2/1000 person-years during an observation period of 67,704 person-years.Multivariable Cox regression analysis indicated age(hazard ratio[HR],1.07;95%confidence interval[CI]:1.06–1.09;P<0.001),male(HR,1.30;95%CI:1.05–1.62;P=0.018),a history of hypertension(HR,1.55;95%CI:1.23–1.95;P<0.001),a history of cardiac diseases(HR,3.23;95%CI:2.34–4.45;P<0.001),atrial premature complex(APC)(HR,2.82;95%CI:2.17–3.68;P<0.001),atrial flutter(HR,18.68;95%CI:7.37–47.31;P<0.001),junctional premature complex(JPC)(HR,3.57;95%CI:1.59–8.02;P=0.002),junctional rhythm(HR,18.24;95%CI:5.83–57.07;P<0.001),ventricular premature complex(VPC)(HR,1.76;95%CI:1.13–2.75,P=0.012),short PR interval(HR,5.49;95%CI:1.36–22.19;P=0.017),right atrial enlargement(HR,6.22;95%CI:1.54–25.14;P=0.010),and pacing rhythm(HR,3.99;95%CI:1.57–10.14;P=0.004)were independently associated with the incidence of AF.Conclusions:The present incidence of AF was 5.2/1000 person-years in the studied population aged over 60 years in China.Among various ECG abnormalities,only APC,atrial flutter,JPC,junctional rhythm,short PR interval,VPC,right atrial enlargement,and pacing rhythm were independently associated with AF incidence.

Deep learning autofluorescence-harmonic microscopy

Laser scanning microscopy has inherent tradeoffs between imaging speed,field of view(FOV),and spatial resolution due to the limitations of sophisticated mechanical and optical setups,and deep learning networks have emerged to overcome these limitations without changing the system.Here,we demonstrate deep learning autofluorescence-harmonic microscopy(DLAM)based on self-alignment attention-guided residual-in-residual dense generative adversarial networks to close the gap between speed,FOV;and quality.Using the framework,we demonstrate label-free large-field multimodal imaging of clinicopathological tissues with enhanced spatial resolution and running time advantages.Statistical quality assessments show that the attention-guided residual dense conneaions minimize the persistent noise,distortions,and scanning fringes that degrade the autofluorescence-harmonic images and avoid reconstruction artifaas in the output images.With the advantages of high contrast,high fidelity,and high speed in image reconstruction,DLAM can act as a powerful tool for the noninvasive evaluation of diseases,neural activity,and embryogenesis.

Antithrombotic Management of Atrial Fibrillation Patients Presenting with Coronary Artery Disease:A Consensus Document of the Chinese Society of Cardiology

The coexistence of coronary artery disease(CAD)and atrial fibrillation(AF)is common in clinical practice.Patients with CAD require antiplatelet therapy to reduce the occurrence of myocardial ischemic events.However,patients with AF at high risk of thromboembolism require oral anticoagulants to reduce the occurrence of thromboembolic events such as stroke.In cases where CAD coexists with AF,the combined use of antiplatelet and anticoagulation therapy can effectively reduce the risk of ischemic and thromboembolic events but increase the risk of bleeding at the same time.The optimal antithrombotic regimen in patients with both CAD and AF has been controversial in clinical practice.In recent years,the expert consensuses on antithrombotic therapy in patients with AF presenting with acute coronary syndrome and/or undergoing percutaneous coronary intervention have been successively released in Europe and North America,and have been updated in a timely manner.In contrast,the guidelines on antithrombotic therapies in China are lacking.Based on published clinical evidence,this consensus incorporated relevant international and Chinese guidelines,consensuses,and expert recommendations,and addressed the issues encountered in the clinical practice of antithrombotic therapy in patients with AF and different types of CAD.The current guideline is of great significance to guide treatment in patients with both CAD and AF in China.

Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation

Atrial fibrillation(AF)is the most common sustained cardiac arrhythmia,significantly impacting patients'quality of life and increasing the risk of death,stroke,heart failure,and dementia.Over the past 2 decades,there have been significant breakthroughs in AF risk prediction and screening,stroke prevention,rhythm control,catheter ablation,and integrated management.During this period,the scale,quality,and experience of AF management in China have greatly improved,providing a solid foundation for the development of guidelines for the diagnosis and management of AF.To further promote standardized AF management,and apply new technologies and concepts to clinical practice in a timely and comprehensive manner,the Chinese Society of Cardiology of the Chinese Medical Association and the Heart Rhythm Committee of the Chinese Society of Biomedical Engineering have jointly developed the Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation.The guidelines have comprehensively elaborated on various aspects of AF management and proposed the CHA,DS,-VASc-60 stroke risk score based on the characteristics of AF in the Asian population.The guidelines have also reevaluated the clinical application of AF screening,emphasized the significance of early rhythm control,and highlighted the central role of catheter ablation in rhythm control.