Assessment of Nitrogen Fixation, Uptake, and Leaching in Maize/Soybean Intercropping System at Varied Soil Depths and under Phosphorus Application in Chinese Agricultural Settings

The study of Nitrogen fixation, uptake, and leaching at different soil depths in the co-cultivation of maize and soybean under phosphorus fertilization is important for sustainable agriculture. This study was conducted in Quzhou, Hebei Province, China, with MC812 maize and Jidou12 soybean varieties. Soil samples were taken from each plot to create a composite sample. The results show that nitrogen concentration varies at different depths and is higher in all treatments between 40 and 100 cm. Incorporating intercropping of maize and soybeans into farming practices can lead to more sustainable and environmentally friendly agriculture in China.

Assessing the Influence of Phosphorus Fertilization on the Growth and Yield of Maize/Soybean Intercrop by Analyzing Nitrogen Uptake

Intercropping, particularly the combination of maize and soybeans, has been widely recognized for its potential to improve nitrogen uptake and promote sustainable agriculture. This study examines the patterns of nitrogen uptake in maize and soybean intercropping systems under different growth stages and phosphorus fertilization levels and investigates the influence of nitrogen uptake on growth parameters such as plant height, leaf area, and biomass accumulation in the maize/soybean intercrop under different phosphorus fertilization regimes. The study also collected chlorophyll samples at different growth stages of maize in monoculture and intercropping with maize or soybean. The results showed that plant height was greater in V10 in both fertilized and unfertilized treatments for intercropped maize and soybean, and chlorophyll concentration was higher in VT intercropped maize. The results also showed a higher accumulation of biomass. Understanding the growth dynamics of these plants in monoculture and intercropping systems and the impact of fertilization practices is crucial for optimizing crop productivity and sustainability in agricultural systems.

The Combination of Achnatherum inebrians Extracts and Soil Microorganisms Inhibited Seed Germination and Seedling Growth in Elymus nutans

In a greenhouse experiment,the effects of soil microorganisms and extracts of Achnatherum inebrians on the seed germination and seedling growth of Elymus nutans were studied.The results showed that both the extracts from aboveground and belowground parts of A.inebrians significantly inhibited the germination rate,germination potential,germination index,vigor index,seedling height,root length,and fresh weight of E.nutans,but increased malondialdehyde content,catalase,peroxidase and superoxide dismutase activity of E.nutans seedlings(p<0.05).The allelopathy of aqueous extracts of the aboveground parts of A.inebrians was stronger than that of the pre-cipitates.Aqueous extracts of the aboveground parts of A.inebrians decreased seed germination rate,germination potential,germination index,vigor index,seedling length,root length,and seedling fresh weight by 10.45%-74.63%,24.18%-32.50%,19.03%-73.36%,37.83%-88.41%,21.42%-53.14%,2.65%-40.21%,and 20.45%-61.36%,respectively,and malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity increased by 8.09%-62.24%,27.83%-86.47%,22.90%-93.17%,and 11.15%-75.91%,respectively.The above indexes were higher in live soil than in sterilized soil.Soil microorganisms increased the allelopathy of A.inebrians.The seed germination rate,germination potential,germination index,vigor index,seedling length,and seedling fresh weight of E.nutans planted in live soil decreased by 8.22%-48.48%,10.00%-51.85%,8.19%-53.26%,16.43%-60.03%,12.91%-28.81%,and 9.09%-22.86%compared with sterilized soil,respectively.Malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity of E.nutans planted in live soil increased by 53.91%-81.06%,15.71%-57.34%,33.33%-86.31%,and 9.78%-52.51%compared with sterilized soil,respectively.The existence of soil microorganisms enhanced the allelopathy of the secondary metabolites of A.inebrians.A combination of microorganisms and aqueous extracts from the aboveground parts of A.inebrians had the strongest allelopathic effect on E.nutans.

Promotion effect of TGF-β-Zfp423-ApoD pathway on lip sensory recovery after nerve sacrifice caused by nerve collateral compensation

Resection of oral and maxillofacial tumors is often accompanied by the inferior alveolar nerve neurectomy,resulting in abnormal sensation in lower lip.It is generally believed that spontaneous sensory recovery in this nerve injury is difficult.However,during our follow-up,patients with inferior alveolar nerve sacrifice showed different degrees of lower lip sensory recovery.In this study,a prospective cohort study was conducted to demonstrate this phenomenon and analyze the factors influencing sensory recovery.

基于大食物观的草地农业发展趋势及关键科学问题

大食物观下,国家食物安全的重点是饲料粮安全。草地农业是全球最重要的食物生产系统之一,既直接生产草畜产品,又间接地为食物生产提供生态保障,满足国家对食物安全、生态安全和边疆稳定不断增长的刚性需求。目前,草地农业保障国家食物安全的水平亟待提高,支撑国家高质量发展的能力亟待加强。种子是草地农业的物质基础,天然草原和栽培草地(也称“人工草地”)是草地农业生产食物的主要基地,草地保护为草地农业开展食物生产“保驾护航”,草地农业系统耦合促进食物生产的效益放大。草地农业是基础性战略产业,保障国家食物安全的水平依靠基础研究的创新。为此,本文分析了草类种质资源挖掘利用与种子生产控制、牧草优质高产栽培与转化、草原生态生产力维持与修复、草地有害生物管理、草地农业系统耦合与管理等5个方面的研究进展,并提出对应的关键科学问题。

Biomass-derived porous carbon with single-atomic cobalt toward high-performance aqueous zinc-sulfur batteries at room temperature

Aqueous zinc-sulfur batteries at room temperature hold great potential for next-generation energy storage technology due to their low cost,safety and high energy density.However,slow reaction kinetics and high activation energy at the sulfur cathode pose great challenges for the practical applications.Herein,biomass-derived carbon with single-atomic cobalt sites(MMPC-Co)is synthesized as the cathode in Zn-S batteries.The catalysis of single-atom Co sites greatly promotes the transform of cathode electrolyte interface(CEI)on the cathode surface,while offering accelerated charge transfer rate for high conversion reversibility and large electrochemical surface area(ECSA)for high electrocatalytic current.Furthermore,the rich pore structure not only physically limits sulfur loss,but also accelerates the transport of zinc ions.In addition,the large pore volume of MMPC-Co is able to relieve the stress effect caused by the volume expansion of Zn S during charge/discharge cycles,thereby maintaining the stability of electrode structure.Consequently,the sulfur cathode maintains a high specific capacity of 729.96 m A h g^(-1)after 500 cycles at4 A g^(-1),which is much better than most cathode materials reported in the literature.This work provides new insights into the design and development of room-temperature aqueous Zn-S batteries.

Engineering porosity into trimetallic PtPdNi nanospheres for enhanced electrocatalytic oxygen reduction activity

Platinum(Pt)-based multi-metallic nanostructures show great promise as electrocatalysts for the oxygen reduction reaction(ORR) in fuel cell cathodes. Herein, we report a simple, one-step surfactant-directed synthetic strategy to directly synthesize tri-metallic PtPdNi mesoporous nanospheres(PtPdNi MNs) in a high yield. The synthesis could be accomplished in aqueous solution at mild reaction temperature(40C)without needing any organic solvent, yielding well-dispersed PtPdNi MNs with uniform shape and narrow size distribution. Benefitting from their unique mesoporous and highly open structure and tri-metallic composition, the as-synthesized PtPdNi MNs demonstrate superior catalytic activity and stability for ORR in acidic solution in comparison with PtPdNi nanodendrites(PtPdNi NDs), PtPd MNs and commercial Pt/C catalyst. The present approach may open a reliable path to the design of advanced electrocatalysts with desired performance.

Farmers'Willingness to Withdraw from Rural Homesteads

In order to grasp the relationship between farmers'willingness and behavior to withdraw from rural homesteads,based on the theory of planned behavior,a survey was conducted in Jizhou District,Tianjin using convenience sampling method.A total of 443 valid questionnaires were collected and they were analyzed by SPSS.The results are as follows.(i)The willingness of farmers to withdraw from rural homesteads is affected by pre-cognitive factors such as behavioral attitude,subject norm and perceived behavior control.(ii)Among the benefits that can be brought by the withdrawal of homesteads,farmers value the improvement of the housing environment the most.(iii)Family members'view and relatives and neighbors'withdrawing from homesteads also exerts greater pressure on farmers.(iv)Farmers generally lack trust in the village committees or government departments'claims.(v)The cost of relocation also restricts the perceived behavior control of farmers'homesteads withdrawing.Based on above result,the following suggestions are made:strengthening policy publicity,raising farmers'awareness of policies related to the withdrawal of homesteads,fully respecting farmers'wishes,promoting the withdrawal of rural homesteads in an orderly manner,expanding the scope of compensation for withdrawal of rural homesteads,and enriching compensation methods.

Facial liposuction combined with botulinum toxin type A:A technique for lower facial contouring

Background:Botulinum toxin type A injection,a noninvasive alternative method for treating masseteric hypertrophy,is inadequate for treating patients with a round lower face.This study aimed to investigate the operative technique and clinical results of liposuction followed by botulinum toxin type A injections in patients with masseteric hypertrophy and excessive subcutaneous fat.Methods:Sixty-five patients(50 women and 15 men)were treated using this technique between May 2014 and January 2019.Their mean age was 26.3 years(range,18–35 years)and the mean follow-up period was 13 months(range,8–18 months).Results:All patients achieved slimmer lower cheeks with improved jaw definitions after the procedure.Among the 65 patients,61(94%)expressed satisfaction with the results and believed that the procedure produced their desired face shape.No major complications were observed.The effect of this combination treatment remained stable for 12 months after the procedure.Conclusion:The authors believe that liposuction followed by botulinum toxin type A injections is an effective technique for the treatment of masseteric hypertrophy and excessive subcutaneous fat.It is also a relatively simple and safe treatment approach.

Mechanical Behavior and Microstructure of Ultrasonic-Spot-Welded Al/Cu Dissimilar Joints with Zn Interlayer

The effect of Zn interlayer on the microstructural evolution and mechanical behavior of dissimilar ultrasonic-spot-welded Al/Cu joints was investigated.The tensile lap shear strength in relation to welding energy was analyzed.The experimental results show that two intermetallic compounds,Cu5Zn8 and Al2Cu,were generated at the interface of the ultrasonic-spotwelded Al/Cu joint with a Zn interlayer.The primary joining mechanisms of the joint included the intermetallic compound bonding and metallic bonding caused by solid shear plastic deformation.Meanwhile,with increasing welding energy,the plastic deformation of the material became more substantial.With increasing welding energy,the tensile lap shear strength of the joints first increased and then decreased for the ultrasonic-spot-welded Al/Cu joints with and without Zn interlayers.Under the energy input of 700 J,the bearing load capacity of the ultrasonic-spot-welded Al/Cu joints with a Zn interlayer improved signifi cantly due to the observed intermetallic compound(Cu5Zn8).

Difficulties and Countermeasures of Rural Human Settlement Environment Governance in Tianjin

The course of rural human settlement environment governance in Tianjin could be roughly divided into four stages:germination,initiation,promotion and deepening.After the development for nearly 20 years,rural human settlement environment governance of Tianjin is faced with many difficulties,such as imperfect village construction planning,poor use effect of sewage facilities,low participation of farmers,and insufficient financial investment.Therefore,some countermeasures and suggestions are put forward,such as scientific planning and overall consideration,innovating financing mechanism,encouraging diversified investment of funds,and strengthening the publicity of rural human settlement environment governance.

Study on the Synergetic Mechanism for the Dynamic Evaluation of Electricity Market Operational Efficiency

In Synergetics, when a complex system evolves from one sate to another, the order parameter plays a dominant role. We can analyze the complex system state by studying the dynamic of order parameter. We developed a synergetic model of electricity market operation system, and studied the dynamic process of the system with empirical example, which revealed the internal mechanism of the system evolution. In order to verify the accuracy of the synergetic model, fourth-order Runge-Kutta algorithm and grey relevance method were used. Finally, we found that the reserve rate of generation was the order parameter of the system. Then we can use the principle of Synergetics to evaluate the efficiency of electricity market operation.

Development of Agricultural Product Logistics in Tianjin in the Context of the Coordinated Development Strategy of Beijing-Tianjin-Hebei Region

Since February 26,2014,Chinese president Xi Jinping of the Central Committee of the Communist Party of China listened to the report on the coordinated development of Beijing-Tianjin-Hebei Region and delivered an important speech,and officially raised the coordinated development of Beijing-Tianjin-Hebei Region as a major national strategy,the integration of Beijing-Tianjin-Hebei Region has entered the"fast lane".Guided by accelerating the construction of agricultural product supply areas,agricultural high-tech industry demonstration areas,and agricultural product logistics center areas,Tianjin seizes the opportunity of coordinated development of Beijing-Tianjin-Hebei Region,brings into full play to the advantages of Tianjin s three-dimensional transportation network,perfect market system,high-quality port services,rapid growth of cold chain and e-commerce,to promote the faster and better development of Tianjin s agriculture.In addition,focusing on comprehensively improving Tianjin s regional agricultural product logistics service capabilities,Tianjin is establishing a distribution center for agricultural products,an e-commerce center,and a high-end agricultural product distribution center serving the Beijing-Tianjin-Hebei Region,to promote the construction of Tianjin agricultural product logistics center.

Survey and Analysis on the Students Satisfaction with Undergraduate Teaching Management in Local Agricultural Colleges and Universities:A Case Study of Tianjin Agricultural University

Local agricultural colleges and universities undertake the important task of training rural revitalization talents suitable for regional characteristics.Only by mastering students'satisfaction with teaching management can we find the problems existing in teaching management.Taking Tianjin Agricultural University as an example,this paper analyzes the undergraduates'satisfaction with teaching management by questionnaire and SPSS24.0.The results show that undergraduates can actively and actively participate in undergraduate teaching management,but their satisfaction is not high.There are significant differences in teaching evaluation management satisfaction among students of different majors and grades.It is suggested to improve the level of teaching management from the aspects of guiding and cultivating a new concept of management and education,establishing and perfecting a scientific and rigorous teaching management system,strengthening the information-based construction of teaching management and strengthening personnel training.

我国草原病虫鼠害现状、研究进展与治理对策

中国草地面积2.65亿公顷,具有范围广、类型多的特点,是我国重要的陆地生态系统,也是我国畜牧业可持续发展的主要载体。长期以来,草原病害、虫害、鼠害频发,一直是威胁我国草原生态安全、畜牧业生产和人民身体健康的重要生物灾害。近年来,国家对草原生态保护与修复工作给予了大力支持和投入,草原病虫鼠害治理取得了显著进展。但是,在当前气候变化与人类活动不断加剧的影响下,草地病害、虫害、鼠害的发生和防控面临新的困难和挑战。由于草地病虫鼠害种类多、分布范围广、治理难度大,整体防控形势依然严峻,在未来仍需加大研究和治理力度。本文简要总结了我国草原病虫鼠害现状及研究进展,梳理和凝练了当前治理中存在的关键科学问题,并提出了相应的治理对策与建议。

Twin peaks of in-hospital mortality among patients with STEMI across five phases of COVID-19 outbreak in China:a nation-wide study

Lockdown and re-opening may become cyclical due to the recurrent waves of the COVID-19 epidemic.Few studies have examined temporal trends and determinants of in-hospital mortality among patients with ST-segment elevation myocardial infarction(STEMI),a life-threatening condition that requires emergency medical care.Using nation-wide data before,during and after the Wuhan lockdown,we aimed to depict temporal patterns and major determinants of STEMI in-hospital mortality in China across five time periods of the COVID-19 epidemic.We analyzed the data of 283,661 STEMI patients who were admitted to 4,487 chest-pain-centers across China,from January 1,2019 to May 31,2020.Compared with the period before the lockdown,STEMI in-hospital mortality increased by 25%(OR 1.25,95%CI 1.16–1.34)during Early Lockdown,by 12%(OR 1.12,95%CI 1.03–1.22)during Later Lockdown,by 35%(OR 1.35,95%CI 1.21–1.50)during Early Lift,and returned to pre-COVID risk(OR 1.04,95%CI 0.95–1.14)during Later Lift.For each time-period,we observed a clear mortality gradient by timing and types of revascularization procedure.In conclusion,the COVID-19 epidemic had a significant adverse impact on STEMI in-hospital mortality,with bimodal peaks during early lockdown and early lift periods and clear mortality gradients by timing and types of revascularization procedure,independent of the time periods.

Development of a biosensor assessing SARS-CoV-2 main protease proteolytic activity in living cells for antiviral drugs screening

Dear Editor,The Coronavirus disease 2019(COVID-19)pandemic is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).The genome of this virus encodes two overlapping polyproteins,pp1a and pp1ab(Wu et al.,2020;Zhou et al.,2020).The functional polypeptides are released from those two polyproteins by extensive proteolytic events.

A conceptual framework and an empirical test of complementarity and facilitation with respect to phosphorus uptake by plant species mixtures

Plant species have different traits for mobilizing sparingly soluble phosphorus (P) resources,which could potentially lead to overyielding in P uptake by plant species mixtures compared to monocultures due to higher P uptake as a result of resource (P) partitioning and facilitation.However,there is circumstantial evidence at best for overyielding as a result of these mechanisms.Overyielding (the outcome) is easily confused with underlying mechanisms because of unclear definitions.We aimed to define a conceptual framework to separate outcome from underlying mechanisms and test it for facilitation and complementarity with respect to P acquisition by three plant species combinations grown on four soils.Our conceptual framework describes both mechanisms of complementarity and facilitation and outcomes (overyielding of mixtures or no overyielding) depending on the competitive ability of the species to uptake the mobilized P.Millet/chickpea mixtures were grown in pots on two calcareous soils mixed with calcium-bound P (CaP) and phytate P (PhyP).Cabbage/faba bean mixtures were grown on both acid and neutral soils mixed with P-coated iron (hydr)oxide (FeP) and PhyP.Wheat/maize mixtures were grown on all four soils.Rhizosphere carboxylate concentration and acid phosphatase activity (mechanisms) as well as plant P uptake and biomass (outcome) were determined for monocultures rhizosphere and species mixtures.Facilitation of P uptake occurred in millet/chickpea mixtures on one calcareous soil.We found no indications for P acquisition from different P sources,neither in millet/chickpea,nor in cabbage/faba bean mixtures.Cabbage and faba bean on the neutral soil differed in rhizosphere acid phosphatase activity and carboxylate concentration,but showed no overyielding.Wheat and maize,with similar root exudates,showed overyielding (the observed P uptake being 22%higher than the expected P uptake) on one calcareous soil.We concluded that although differences in plant physiological traits (root exudates) provide necessary conditions for complementarity and facilitation with respect to P uptake from different P sources,they do not necessarily result in increased P uptake by species mixtures,because of the relative competitive ability of the mixed species.

Two-Stage Constructions for the Rate-Compatible Shortened Polar Codes

In this paper,we propose the two-stage constructions for the rate-compatible shortened polar(RCSP)codes.For the Stage-I construction,the shortening pattern and the frozen bit are jointly designed to make the shortened bits be completely known by the decoder.Besides,a distance-greedy algorithm is presented to improve the minimum Hamming distance of the codes.To design the remaining Stage-II frozen bits,three different construction algorithms are further presented,called the Reed-Muller(RM)construction,the Gaussian Approximation(GA)construction,and the RM-GA construction.Then we give the row weight distribution numerical results of the generator matrix after the Stage-I and Stage-II constructions,which shows that the proposed constructions can efficiently increase the minimum Hamming distance.Simulation results show that the proposed RCSP codes have excellent frame error rate(FER)performances at different code lengths and code rates.More specifically,the RM-GA construction performs best and can achieve at most 0.8 dB gain compared to the Wang14 and the quasi-uniform puncturing(QUP)schemes.The RM construction is designed completely by the distance-constraint without channel evaluation thus has the simplest structure.Interestingly,it still has better FER performance than the existing shortening/puncturing schemes,especially at high signal noise ratio(SNR)region.

Bifunctional oxygen electrocatalysts for rechargeable zinc-air battery based on MXene and beyond

Oxygen electrocatalysts are of great importance for the air electrode in zinc–air batteries(ZABs).Owing to large surface area,high electrical conductivity and ease of modification,two-dimensional(2D)materials have been widely studied as oxygen electrocatalysts for the rechargable ZABs.The elaborately modified 2D materials-based electrocatalysts,usually exhibit excellent performance toward the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),which have attracted extensive interests of worldwide researchers.Given the rapid development of bifunctional electrocatalysts toward ORR and OER,the latest progress of non-noble electrocatalysts based on layered double hydroxides(LDHs),graphene,and MXenes are intensively reviewed.The discussion ranges from fundamental structure,synthesis,electrocatalytic performance of these catalysts,as well as their applications in the rechargeable ZABs.Finally,the challenges and outlook are provided for further advancing the commercialization of rechargeable ZABs.