A project that puts cameras in the hands of war’s youngest victims offers them away to tell—and show——their stories. Two million children dead.Six millionmaimed or mutilated.Ten million psychologicallydamaged.Such...A project that puts cameras in the hands of war’s youngest victims offers them away to tell—and show——their stories. Two million children dead.Six millionmaimed or mutilated.Ten million psychologicallydamaged.Such is the tragic tally,in the last decade,of the world’s wars.border skirmishes and ethnicconflicts.And it doesn’t stop there.According toa 1999 report by the U.N.’s Special Representativefor Children and Armed Conflict,more than展开更多
In order to improve the accuracy of the photogrammetric joint roughness coefficient(JRC)value,the present study proposed a novel method combining an autonomous shooting parameter selection algorithm with a composite e...In order to improve the accuracy of the photogrammetric joint roughness coefficient(JRC)value,the present study proposed a novel method combining an autonomous shooting parameter selection algorithm with a composite error model.Firstly,according to the depth map-based photogrammetric theory,the estimation of JRC from a three-dimensional(3D)digital surface model of rock discontinuities was presented.Secondly,an automatic shooting parameter selection algorithm was novelly proposed to establish the 3D model dataset of rock discontinuities with varying shooting parameters and target sizes.Meanwhile,the photogrammetric tests were performed with custom-built equipment capable of adjusting baseline lengths,and a total of 36 sets of JRC data was gathered via a combination of laboratory and field tests.Then,by combining the theory of point cloud coordinate computation error with the equation of JRC calculation,a composite error model controlled by the shooting parameters was proposed.This newly proposed model was validated via the 3D model dataset,demonstrating the capability to correct initially obtained JRC values solely based on shooting parameters.Furthermore,the implementation of this correction can significantly reduce errors in JRC values obtained via photographic measurement.Subsequently,our proposed error model was integrated into the shooting parameter selection algorithm,thus improving the rationality and convenience of selecting suitable shooting parameter combinations when dealing with target rock masses with different sizes.Moreover,the optimal combination of three shooting parameters was offered.JRC values resulting from various combinations of shooting parameters were verified by comparing them with 3D laser scan data.Finally,the application scope and limitations of the newly proposed approach were further addressed.展开更多
The orchards usually have rough terrain,dense tree canopy and weeds.It is hard to use GNSS for autonomous navigation in orchard due to signal occlusion,multipath effect,and radio frequency interference.To achieve auto...The orchards usually have rough terrain,dense tree canopy and weeds.It is hard to use GNSS for autonomous navigation in orchard due to signal occlusion,multipath effect,and radio frequency interference.To achieve autonomous navigation in orchard,a visual navigation method based on multiple images at different shooting angles is proposed in this paper.A dynamic image capturing device is designed for camera installation and multiple images can be shot at different angles.Firstly,the obtained orchard images are classified into sky and soil detection stage.Each image is transformed to HSV space and initially segmented into sky,canopy and soil regions by median filtering and morphological processing.Secondly,the sky and soil regions are extracted by the maximum connected region algorithm,and the region edges are detected and filtered by the Canny operator.Thirdly,the navigation line in the current frame is extracted by fitting the region coordinate points.Then the dynamic weighted filtering algorithm is used to extract the navigation line for the soil and sky detection stage,respectively,and the navigation line for the sky detection stage is mirrored to the soil region.Finally,the Kalman filter algorithm is used to fuse and extract the final navigation path.The test results on 200 images show that the accuracy of visual navigation path fitting is 95.5%,and single frame image processing costs 60 ms,which meets the real-time and robustness requirements of navigation.The visual navigation experiments in Camellia oleifera orchard show that when the driving speed is 0.6 m/s,the maximum tracking offset of visual navigation in weed-free and weedy environments is 0.14 m and 0.24 m,respectively,and the RMSE is 30 mm and 55 mm,respectively.展开更多
Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N...Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N response makes it difficult to predict and quantify the effect of water deficit on crop N status.The nitrogen nutrition index(NNI)has been widely used to accurately diagnose crop N status and to evaluate the effectiveness of N application.The decline of NNI under water-limiting conditions has been documented,although the underlying mechanism governing this decline is not fully understood.This study aimed to elucidate the reason for the decline of NNI under waterlimiting conditions and to provide insights into the accurate utilization of NNI for assessing crop N status under different water-N interaction treatments.Rainout shelter experiments were conducted over three growing seasons from 2018 to 2021 under different N(75 and 225 kg N ha^(-1),low N and high N)and water(120 to 510 mm,W0 to W3)co-limitation treatments.Plant N accumulation,shoot biomass(SB),plant N concentration(%N),soil nitrate-N content,actual evapotranspiration(ET_a),and yield were recorded at the stem elongation,booting,anthesis and grain filling stages.Compared to W0,W1 to W3 treatments exhibited NNI values that were greater by 10.2 to 20.5%,12.6to 24.8%,14 to 24.8%,and 16.8 to 24.8%at stem elongation,booting,anthesis,and grain filling,respectively,across the 2018-2021 seasons.This decline in NNI under water-limiting conditions stemmed from two main factors.First,reduced ET_(a) and SB led to a greater critical N concentration(%N_(c))under water-limiting conditions,which contributed to the decline in NNI primarily under high N conditions.Second,changes in plant%N played a more significant role under low N conditions.Plant N accumulation exhibited a positive allometric relationship with SB and a negative relationship with soil nitrate-N content under water-limiting conditions,indicating co-regulation by SB and the soil nitrate-N content.However,this regulation was influenced by water availability.Plant N accumulation sourced from the soil nitrate-N content reflects soil N availability.Greater soil water availability facilitated greater absorption of soil nitrate-N into the plants,leading to a positive correlation between plant N accumulation and ET_(a)across the different water-N interaction treatments.Therefore,considering the impact of soil water availability is crucial when assessing soil N availability under water-limiting conditions.The findings of this study provide valuable insights into the factors contributing to the decline in NNI among different water-N interaction treatments and can contribute to the more accurate utilization of NNI for assessing winter wheat N status.展开更多
The inflation tests of rubbery membranes have been widely employed as an efficient method to characterize the stress response as biaxial loading states.However,most of the previous theoretical works have employed clas...The inflation tests of rubbery membranes have been widely employed as an efficient method to characterize the stress response as biaxial loading states.However,most of the previous theoretical works have employed classic hyperelastic models to analyze the deformation behaviors of inflated membranes.The classic models have been demonstrated to lack the ability to capturing the biaxial deformation of rubbers.To address this issue,we have combined the analytical method and the finite element simulation to investigate the deformation response of soft membranes with different constitutive relationships.For the analytical method,the governing ordinary differential equations have been set up for the boundary value problem of inflation tests and further solved using the shooting method.The analytical results are consistent with those obtained from finite element simulation.The results show that the deformation belongs to the unequal biaxial condition rather than the equi-biaxial state unless a neo-Hookean model is adopted.We also perform a parameter study using the extended eight-chain model,which shows that a change in different parameters affects the mechanical response of inflation tests variously.This work may shed light on the future experimental characterization of soft materials using inflation experiments.展开更多
This paper proposes a novel impulsive thrust strategy guided by optimal continuous thrust strategy to address two-player orbital pursuit-evasion game under impulsive thrust control.The strategy seeks to enhance the in...This paper proposes a novel impulsive thrust strategy guided by optimal continuous thrust strategy to address two-player orbital pursuit-evasion game under impulsive thrust control.The strategy seeks to enhance the interpretability of impulsive thrust strategy by integrating it within the framework of differential game in traditional continuous systems.First,this paper introduces an impulse-like constraint,with periodical changes in thrust amplitude,to characterize the impulsive thrust control.Then,the game with the impulse-like constraint is converted into the two-point boundary value problem,which is solved by the combined shooting and deep learning method proposed in this paper.Deep learning and numerical optimization are employed to obtain the guesses for unknown terminal adjoint variables and the game terminal time.Subsequently,the accurate values are solved by the shooting method to yield the optimal continuous thrust strategy with the impulse-like constraint.Finally,the shooting method is iteratively employed at each impulse decision moment to derive the impulsive thrust strategy guided by the optimal continuous thrust strategy.Numerical examples demonstrate the convergence of the combined shooting and deep learning method,even if the strongly nonlinear impulse-like constraint is introduced.The effect of the impulsive thrust strategy guided by the optimal continuous thrust strategy is also discussed.展开更多
We subjected seeds and shoots of eelgrass Zostera marina to different combinations of sediment loosening(0(control),5,10 cm in depth)and sediment fertilization(0(control),40,80,120,160 g/m^(2))through a field experime...We subjected seeds and shoots of eelgrass Zostera marina to different combinations of sediment loosening(0(control),5,10 cm in depth)and sediment fertilization(0(control),40,80,120,160 g/m^(2))through a field experiment involving seed sowing and shoot transplantation from September 2020 to September 2021.Growth analysis revealed optimum ranges for sediment fertiliza-tion and sediment loosening were 88.8-93.8 g/m^(2)and 5.3-5.8 cm for Z.marina seed sowing,as well as 79.7-86.7 g/m^(2)and 5.9-6.5 cm for Z.marina shoot transplanting,respectively.The shoot densities of Z.marina exposed to these optimum range of sediment fer-tilization and sediment loosening were 1.1-1.3 times of those in the control group.Porewater nutrients are key environmental factors affecting seed germination and shoot growth of Z.marina.The results provide valuable insights for enhancing restoration effects of Z.marina.展开更多
The objective of the study was to determine the influence of temperature, relative humidity, and shoot size of Valencia orange trees Citrus sinensis (L.) Osbeck (Sapindales: Rutaceae) on the abundance of eggs and nymp...The objective of the study was to determine the influence of temperature, relative humidity, and shoot size of Valencia orange trees Citrus sinensis (L.) Osbeck (Sapindales: Rutaceae) on the abundance of eggs and nymphal stages of Diaphorina citri Kuwayama (Hemiptera: Liviidae). The experiment was established on 3.18 hectares cultivated with Valencia orange. The number of eggs, nymphs, temperature, relative humidity, and scale of the size of the shoot were recorded from January to July and from September to November 2020. The association of these variables was determined by multiple correspondence analyses. The conservation of the same number of individuals between consecutive samples and the increase in the number of eggs and nymphs was associated with temperature (17˚C - 23˚C), relative humidity (75% - 78%) and the availability of shoots from V1 to VS in March, April, June, and July. The largest number of N1 and N2 nymphs was recorded in January, February, May, and October. The highest population of eggs and nymphs N3 and N5 occurred in September. In November, there was a reduction in eggs and nymphs. Meanwhile, the nymph N4 was presented independently of the variables analyzed.展开更多
Pepper (Capsicum annuum L.) is an important agricultural crop because of the nutritional value of the fruit and its economic importance.Various techniques have been practiced to enhance pepper's productivity and n...Pepper (Capsicum annuum L.) is an important agricultural crop because of the nutritional value of the fruit and its economic importance.Various techniques have been practiced to enhance pepper's productivity and nutritional value.Therefore,this study was conducted to determine the impact of different training methods and biostimulant applications on sweet pepper plants'growth,yield,and chemical composition under greenhouse conditions.For the training method,unpruned plants were compared with one stem and two stem plants.Unpruned plants had the fruit number of 33.98,fruit weight of 2.18 kg·plant^(-1),and total marketable yield of 1 090.0 kg·hm^(-2).One stem plant gave the best average fruit weight of 86.63 g,vitamin C content of 13.66 mg·kg^(-1)FW,and TSS content of 7.21%.However,two stem plants had the highest fruit setting of 62.41%,carotenoid content of 0.14 mg·kg^(-1)FW,and fruit chlorophyll content of 3.57 mg·kg^(-1)FW.For biostimulant applications,control plants were compared with the Disper Root (DR) and Disper Vital (DV).DR application significantly increased total sugar,carotenoid,fruit chlorophyll,and TSS contents compared to the control and DV applications.While,applying DV increased fruit setting,plant fruit number,weight,and total marketable yield.In addition,integrating one stem plant with the DR application improved fiber,vitamin C,and TSS contents significantly.Two stem plants,and the DV application improved fruit setting and carotenoid content.Thus,one and two stem training methods integrated with the DR and DV biostimulant applications could be considered for developing agricultural practices to obtain commercial yield and improve the nutrition values of sweet peppers,as unpruned plants without biostimulant applications have a negative impact.展开更多
Many staple crops like wheat,soybeans,and maize stubbornly resist regrowing from lab-grown tissues-a major bottleneck for genetic modification and improvement of these crops.A Cell study in June 2024 may become a game...Many staple crops like wheat,soybeans,and maize stubbornly resist regrowing from lab-grown tissues-a major bottleneck for genetic modification and improvement of these crops.A Cell study in June 2024 may become a game-changer.Led by Dr.DENG Lei(Shandong Agricultural University)and Dr.LI Chuanyou(the CAS Institute of Genetics and Developmental Biology),the collaborative effort identified a peptide called REGENERATION FACTOR1(REF1)as a local wound signal that regulates damage-triggered tissue repair and organ regeneration.This very finding may greatly expand opportunities for improving crop resilience through targeted bioengineering.展开更多
Rapid growth is an innovative trait of woody bamboos that has been widely studied.However,the genetic basis and evolution of this trait are poorly understood.Taking advantage of genomic resources of 11 representative ...Rapid growth is an innovative trait of woody bamboos that has been widely studied.However,the genetic basis and evolution of this trait are poorly understood.Taking advantage of genomic resources of 11 representative bamboos at different ploidal levels,we integrated morphological,physiological,and transcriptomic datasets to investigate rapid growth.In particular,these bamboos include two large-sized and a small-sized woody species,compared with a diploid herbaceous species.Our results showed that gibberellin A1 was important for the rapid shoot growth of the world's largest bamboo,Dendrocalamus sinicus,and indicated that two gibberellins(GAs)-related genes,KAO and SLRL1,were key to the rapid shoot growth and culm size in woody bamboos.The expression of GAs-related genes exhibited significant subgenome asymmetry with subgenomes A and C demonstrating expression dominance in the large-sized woody bamboos while the generally submissive subgenomes B and D dominating in the small-sized species.The subgenome asymmetry was found to be correlated with the subgenome-specific gene structure,particularly UTRs and core promoters.Our study provides novel insights into the molecular mechanism and evolution of rapid shoot growth following allopolyploidization in woody bamboos,particularly via subgenome asymmetry.These findings are helpful for understanding of how polyploidization in general and subgenome asymmetry in particular contributed to the origin of innovative traits in plants.展开更多
Endodermal cells and starch-accumulating amyloplasts are well-known gravity sensors initiating shoot gravitropism in Arabidopsis thaliana.The transcription factors SHR and SGR1 regulate endodermal cell formation,while...Endodermal cells and starch-accumulating amyloplasts are well-known gravity sensors initiating shoot gravitropism in Arabidopsis thaliana.The transcription factors SHR and SGR1 regulate endodermal cell formation,while PGM has been demonstrated to regulate starch biosynthesis within chloroplasts,which eventually leads to starch accumulation in amyloplasts.However,the molecular mechanisms of gravity sensing in monocot shoots remain largely unexplored.In this study,we investigated the roles of these genes in rice(Oryza sativa),a model monocot,using CRISPR-Cas9 to generate single,double,and higher-order mutants.The rice genome harbors two orthologs each of SHR and SGR and a single ortholog of PGM.Our results revealed that single mutants of OsPGM,but not OsSHR or OsSGR,showed compromised shoot gravitropism.However,double mutants shr1shr2 and sgr1sgr2 displayed wider tiller angles and reduced gravity sensing,suggesting functional redundancy within each gene pair.Higher-order mutants exhibited progressively severe phenotypes,with quintuple mutants almost unresponsive to gravity stimulation.These findings suggest that these genes act additively through distinct but converging pathways in shoot gravitropism regulation.This study provides novel insights into the molecular mechanisms underlying gravity sensing in monocots and offers valuable knowledge for precision breeding to optimize rice architecture.展开更多
Plants undergo dynamic morphological changes in response to fluctuating light conditions.Despite significant progress in elucidating the mechanisms of light signal transduction,the precise influence of light on the de...Plants undergo dynamic morphological changes in response to fluctuating light conditions.Despite significant progress in elucidating the mechanisms of light signal transduction,the precise influence of light on the development and regulation of shoot architecture remains a central research question.Studies focusing on model plants such as Arabidopsis thaliana and rice suggest light modulates shoot architecture through intricate regulatory networks.However,the molecular mechanisms governing the diverse effects of light on horticultural crops are still poorly understood.This review primarily focuses on horticultural crops,integrating research on model plants,including Arabidopsis and rice,to provide an overview of the regulatory mechanisms of light signals in plant architectural development.It also explores the prospects for manipulating light environments in greenhouse management strategies.展开更多
Adoption of Chinese hybrid rice boosts food security in Madagascar As the sun rises over the rice paddies of Mahitsy,Ramos Rakotorinina breathes in the cool morning air,watching the emerald green shoots of Chinese hyb...Adoption of Chinese hybrid rice boosts food security in Madagascar As the sun rises over the rice paddies of Mahitsy,Ramos Rakotorinina breathes in the cool morning air,watching the emerald green shoots of Chinese hybrid rice sway softly in the breeze.展开更多
Bean(Phaseolus vulgaris)is a globally important legume crop valued for its nutritional content and adaptability.Establishing a robust root system during early growth is critical for optimal nutrient uptake,shoot devel...Bean(Phaseolus vulgaris)is a globally important legume crop valued for its nutritional content and adaptability.Establishing a robust root system during early growth is critical for optimal nutrient uptake,shoot development,and increased resistance to biotic stress.This study evaluated the effects of exogenous indole-3-butyric acid(IBA)on root and shoot development in two bean cultivars,Onceler-98 and Topcu,during the seedling stage.IBA was applied at four concentrations:0(control),50,100,and 150μM.Morphological parameters measured included root length(RL),root fresh weight(RFW),root dry weight(RDW),root nodule number(RNN),shoot length(SL),shoot fresh weight(SFW),and shoot dry weight(SDW).The experiment followed a randomized complete block design with four replications.Significant(p≤0.05)and highly significant(p≤0.01)differences were observed across treatments and cultivars.The results indicated that Onceler-98 generally responded more favorably to IBA application,with optimal growth performance observed at 100μM.In contrast,Topcu was less responsive to IBA overall,and high concentrations-particularly 150μM-tended to suppress nodule formation.展开更多
In November 2024,the famous British zoologist Jane Goodall,known as“the Mother of Chimpanzees”,visited China for the 17th time.During her trip,she celebrated the 30th anniversary of her“Roots&Shoots”project in...In November 2024,the famous British zoologist Jane Goodall,known as“the Mother of Chimpanzees”,visited China for the 17th time.During her trip,she celebrated the 30th anniversary of her“Roots&Shoots”project in China and participated in the 8th“It's Warm Winter”event organized by the Beijing It's Animal Protection Public Welfare Foundation(It's Fund).展开更多
Core shooting process plays a decisive role in the quality of sand cores, and core box vents distribution is one of the most important factor determining the effectiveness of core shooting process. In this paper, the ...Core shooting process plays a decisive role in the quality of sand cores, and core box vents distribution is one of the most important factor determining the effectiveness of core shooting process. In this paper, the influence of core box vents distribution on the flow dynamics of core shooting process was investigated based on in situ experimental observations with transparent core box, high-speed camera and pressure measuring system. Attention was focused on the variation of both the flow behavior of sand and pressure curves due to different vents distribution. Taking both kinetic and frictional stress into account, a kinetic-frictional constitutive model was established to describe the internal momentum transfer in the solid phase. Two-fluid model(TFM) simulation was then performed and good agreement was achieved between the experimental and simulated results on both the flow behavior of sand and the pressure curves. It was found that vents distribution has direct effect on the pressure difference of different locations in the core box, which determines the buoyancy force exerting on the sand particles and significantly influences the filling process of core sand.展开更多
In order to cope with the increasing threat of the ballistic missile(BM)in a shorter reaction time,the shooting policy of the layered defense system needs to be optimized.The main decisionmaking problem of shooting op...In order to cope with the increasing threat of the ballistic missile(BM)in a shorter reaction time,the shooting policy of the layered defense system needs to be optimized.The main decisionmaking problem of shooting optimization is how to choose the next BM which needs to be shot according to the previous engagements and results,thus maximizing the expected return of BMs killed or minimizing the cost of BMs penetration.Motivated by this,this study aims to determine an optimal shooting policy for a two-layer missile defense(TLMD)system.This paper considers a scenario in which the TLMD system wishes to shoot at a collection of BMs one at a time,and to maximize the return obtained from BMs killed before the system demise.To provide a policy analysis tool,this paper develops a general model for shooting decision-making,the shooting engagements can be described as a discounted reward Markov decision process.The index shooting policy is a strategy that can effectively balance the shooting returns and the risk that the defense mission fails,and the goal is to maximize the return obtained from BMs killed before the system demise.The numerical results show that the index policy is better than a range of competitors,especially the mean returns and the mean killing BM number.展开更多
文摘A project that puts cameras in the hands of war’s youngest victims offers them away to tell—and show——their stories. Two million children dead.Six millionmaimed or mutilated.Ten million psychologicallydamaged.Such is the tragic tally,in the last decade,of the world’s wars.border skirmishes and ethnicconflicts.And it doesn’t stop there.According toa 1999 report by the U.N.’s Special Representativefor Children and Armed Conflict,more than
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52225904 and 52039007)the Fundamental Research Funds for the Central Universities,CHD(Grant No.300102212207).
文摘In order to improve the accuracy of the photogrammetric joint roughness coefficient(JRC)value,the present study proposed a novel method combining an autonomous shooting parameter selection algorithm with a composite error model.Firstly,according to the depth map-based photogrammetric theory,the estimation of JRC from a three-dimensional(3D)digital surface model of rock discontinuities was presented.Secondly,an automatic shooting parameter selection algorithm was novelly proposed to establish the 3D model dataset of rock discontinuities with varying shooting parameters and target sizes.Meanwhile,the photogrammetric tests were performed with custom-built equipment capable of adjusting baseline lengths,and a total of 36 sets of JRC data was gathered via a combination of laboratory and field tests.Then,by combining the theory of point cloud coordinate computation error with the equation of JRC calculation,a composite error model controlled by the shooting parameters was proposed.This newly proposed model was validated via the 3D model dataset,demonstrating the capability to correct initially obtained JRC values solely based on shooting parameters.Furthermore,the implementation of this correction can significantly reduce errors in JRC values obtained via photographic measurement.Subsequently,our proposed error model was integrated into the shooting parameter selection algorithm,thus improving the rationality and convenience of selecting suitable shooting parameter combinations when dealing with target rock masses with different sizes.Moreover,the optimal combination of three shooting parameters was offered.JRC values resulting from various combinations of shooting parameters were verified by comparing them with 3D laser scan data.Finally,the application scope and limitations of the newly proposed approach were further addressed.
基金National Key Research and Development Program of China(2022YFD2202103)National Natural Science Foundation of China(31971798)+2 种基金Zhejiang Provincial Key Research&Development Plan(2023C02049、2023C02053)SNJF Science and Technology Collaborative Program of Zhejiang Province(2022SNJF017)Hangzhou Agricultural and Social Development Research Project(202203A03)。
文摘The orchards usually have rough terrain,dense tree canopy and weeds.It is hard to use GNSS for autonomous navigation in orchard due to signal occlusion,multipath effect,and radio frequency interference.To achieve autonomous navigation in orchard,a visual navigation method based on multiple images at different shooting angles is proposed in this paper.A dynamic image capturing device is designed for camera installation and multiple images can be shot at different angles.Firstly,the obtained orchard images are classified into sky and soil detection stage.Each image is transformed to HSV space and initially segmented into sky,canopy and soil regions by median filtering and morphological processing.Secondly,the sky and soil regions are extracted by the maximum connected region algorithm,and the region edges are detected and filtered by the Canny operator.Thirdly,the navigation line in the current frame is extracted by fitting the region coordinate points.Then the dynamic weighted filtering algorithm is used to extract the navigation line for the soil and sky detection stage,respectively,and the navigation line for the sky detection stage is mirrored to the soil region.Finally,the Kalman filter algorithm is used to fuse and extract the final navigation path.The test results on 200 images show that the accuracy of visual navigation path fitting is 95.5%,and single frame image processing costs 60 ms,which meets the real-time and robustness requirements of navigation.The visual navigation experiments in Camellia oleifera orchard show that when the driving speed is 0.6 m/s,the maximum tracking offset of visual navigation in weed-free and weedy environments is 0.14 m and 0.24 m,respectively,and the RMSE is 30 mm and 55 mm,respectively.
基金supported by the National Natural Science Foundation of China(51609247)the Henan Provincial Natural Science Foundation,China(222300420589,202300410553)+4 种基金the Central Public-interest Scientific Institution Basal Research Fund,China(FIRI2022-22)the Science&Technology Fundamental Resources Investigation Program,China(2022FY101601)the Science and Technology Project of Xinxiang City,Henan Province,China(GG2021024)the Major Special Science and Technology Project of Henan Province,China(221100110700)the Joint Fund of Science and Technology Research and Development Plan of Henan Province,China(Superior Discipline Cultivation)(222301420104)。
文摘Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N response makes it difficult to predict and quantify the effect of water deficit on crop N status.The nitrogen nutrition index(NNI)has been widely used to accurately diagnose crop N status and to evaluate the effectiveness of N application.The decline of NNI under water-limiting conditions has been documented,although the underlying mechanism governing this decline is not fully understood.This study aimed to elucidate the reason for the decline of NNI under waterlimiting conditions and to provide insights into the accurate utilization of NNI for assessing crop N status under different water-N interaction treatments.Rainout shelter experiments were conducted over three growing seasons from 2018 to 2021 under different N(75 and 225 kg N ha^(-1),low N and high N)and water(120 to 510 mm,W0 to W3)co-limitation treatments.Plant N accumulation,shoot biomass(SB),plant N concentration(%N),soil nitrate-N content,actual evapotranspiration(ET_a),and yield were recorded at the stem elongation,booting,anthesis and grain filling stages.Compared to W0,W1 to W3 treatments exhibited NNI values that were greater by 10.2 to 20.5%,12.6to 24.8%,14 to 24.8%,and 16.8 to 24.8%at stem elongation,booting,anthesis,and grain filling,respectively,across the 2018-2021 seasons.This decline in NNI under water-limiting conditions stemmed from two main factors.First,reduced ET_(a) and SB led to a greater critical N concentration(%N_(c))under water-limiting conditions,which contributed to the decline in NNI primarily under high N conditions.Second,changes in plant%N played a more significant role under low N conditions.Plant N accumulation exhibited a positive allometric relationship with SB and a negative relationship with soil nitrate-N content under water-limiting conditions,indicating co-regulation by SB and the soil nitrate-N content.However,this regulation was influenced by water availability.Plant N accumulation sourced from the soil nitrate-N content reflects soil N availability.Greater soil water availability facilitated greater absorption of soil nitrate-N into the plants,leading to a positive correlation between plant N accumulation and ET_(a)across the different water-N interaction treatments.Therefore,considering the impact of soil water availability is crucial when assessing soil N availability under water-limiting conditions.The findings of this study provide valuable insights into the factors contributing to the decline in NNI among different water-N interaction treatments and can contribute to the more accurate utilization of NNI for assessing winter wheat N status.
基金supported by the National Natural Science Foundation of China(Grant Nos.12211530061 and 12321002)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LD22A020001)the 111 Project(Grant No.B21034).
文摘The inflation tests of rubbery membranes have been widely employed as an efficient method to characterize the stress response as biaxial loading states.However,most of the previous theoretical works have employed classic hyperelastic models to analyze the deformation behaviors of inflated membranes.The classic models have been demonstrated to lack the ability to capturing the biaxial deformation of rubbers.To address this issue,we have combined the analytical method and the finite element simulation to investigate the deformation response of soft membranes with different constitutive relationships.For the analytical method,the governing ordinary differential equations have been set up for the boundary value problem of inflation tests and further solved using the shooting method.The analytical results are consistent with those obtained from finite element simulation.The results show that the deformation belongs to the unequal biaxial condition rather than the equi-biaxial state unless a neo-Hookean model is adopted.We also perform a parameter study using the extended eight-chain model,which shows that a change in different parameters affects the mechanical response of inflation tests variously.This work may shed light on the future experimental characterization of soft materials using inflation experiments.
基金funded by the National Natural Science Foundation of China(No.U21B6001)。
文摘This paper proposes a novel impulsive thrust strategy guided by optimal continuous thrust strategy to address two-player orbital pursuit-evasion game under impulsive thrust control.The strategy seeks to enhance the interpretability of impulsive thrust strategy by integrating it within the framework of differential game in traditional continuous systems.First,this paper introduces an impulse-like constraint,with periodical changes in thrust amplitude,to characterize the impulsive thrust control.Then,the game with the impulse-like constraint is converted into the two-point boundary value problem,which is solved by the combined shooting and deep learning method proposed in this paper.Deep learning and numerical optimization are employed to obtain the guesses for unknown terminal adjoint variables and the game terminal time.Subsequently,the accurate values are solved by the shooting method to yield the optimal continuous thrust strategy with the impulse-like constraint.Finally,the shooting method is iteratively employed at each impulse decision moment to derive the impulsive thrust strategy guided by the optimal continuous thrust strategy.Numerical examples demonstrate the convergence of the combined shooting and deep learning method,even if the strongly nonlinear impulse-like constraint is introduced.The effect of the impulsive thrust strategy guided by the optimal continuous thrust strategy is also discussed.
基金supported by the National Key Re-search and Development Program of China(No.2023 YFD2401102)the National Natural Science Foundation of China(No.42076100)the Joint Research Center for Conservation,Restoration&Sustainable Utilization of Marine Ecology of Ocean University of China-China State Shipbuilding Corporation Environmental Development Co.,Ltd.(No.H20240008).
文摘We subjected seeds and shoots of eelgrass Zostera marina to different combinations of sediment loosening(0(control),5,10 cm in depth)and sediment fertilization(0(control),40,80,120,160 g/m^(2))through a field experiment involving seed sowing and shoot transplantation from September 2020 to September 2021.Growth analysis revealed optimum ranges for sediment fertiliza-tion and sediment loosening were 88.8-93.8 g/m^(2)and 5.3-5.8 cm for Z.marina seed sowing,as well as 79.7-86.7 g/m^(2)and 5.9-6.5 cm for Z.marina shoot transplanting,respectively.The shoot densities of Z.marina exposed to these optimum range of sediment fer-tilization and sediment loosening were 1.1-1.3 times of those in the control group.Porewater nutrients are key environmental factors affecting seed germination and shoot growth of Z.marina.The results provide valuable insights for enhancing restoration effects of Z.marina.
文摘The objective of the study was to determine the influence of temperature, relative humidity, and shoot size of Valencia orange trees Citrus sinensis (L.) Osbeck (Sapindales: Rutaceae) on the abundance of eggs and nymphal stages of Diaphorina citri Kuwayama (Hemiptera: Liviidae). The experiment was established on 3.18 hectares cultivated with Valencia orange. The number of eggs, nymphs, temperature, relative humidity, and scale of the size of the shoot were recorded from January to July and from September to November 2020. The association of these variables was determined by multiple correspondence analyses. The conservation of the same number of individuals between consecutive samples and the increase in the number of eggs and nymphs was associated with temperature (17˚C - 23˚C), relative humidity (75% - 78%) and the availability of shoots from V1 to VS in March, April, June, and July. The largest number of N1 and N2 nymphs was recorded in January, February, May, and October. The highest population of eggs and nymphs N3 and N5 occurred in September. In November, there was a reduction in eggs and nymphs. Meanwhile, the nymph N4 was presented independently of the variables analyzed.
文摘Pepper (Capsicum annuum L.) is an important agricultural crop because of the nutritional value of the fruit and its economic importance.Various techniques have been practiced to enhance pepper's productivity and nutritional value.Therefore,this study was conducted to determine the impact of different training methods and biostimulant applications on sweet pepper plants'growth,yield,and chemical composition under greenhouse conditions.For the training method,unpruned plants were compared with one stem and two stem plants.Unpruned plants had the fruit number of 33.98,fruit weight of 2.18 kg·plant^(-1),and total marketable yield of 1 090.0 kg·hm^(-2).One stem plant gave the best average fruit weight of 86.63 g,vitamin C content of 13.66 mg·kg^(-1)FW,and TSS content of 7.21%.However,two stem plants had the highest fruit setting of 62.41%,carotenoid content of 0.14 mg·kg^(-1)FW,and fruit chlorophyll content of 3.57 mg·kg^(-1)FW.For biostimulant applications,control plants were compared with the Disper Root (DR) and Disper Vital (DV).DR application significantly increased total sugar,carotenoid,fruit chlorophyll,and TSS contents compared to the control and DV applications.While,applying DV increased fruit setting,plant fruit number,weight,and total marketable yield.In addition,integrating one stem plant with the DR application improved fiber,vitamin C,and TSS contents significantly.Two stem plants,and the DV application improved fruit setting and carotenoid content.Thus,one and two stem training methods integrated with the DR and DV biostimulant applications could be considered for developing agricultural practices to obtain commercial yield and improve the nutrition values of sweet peppers,as unpruned plants without biostimulant applications have a negative impact.
文摘Many staple crops like wheat,soybeans,and maize stubbornly resist regrowing from lab-grown tissues-a major bottleneck for genetic modification and improvement of these crops.A Cell study in June 2024 may become a game-changer.Led by Dr.DENG Lei(Shandong Agricultural University)and Dr.LI Chuanyou(the CAS Institute of Genetics and Developmental Biology),the collaborative effort identified a peptide called REGENERATION FACTOR1(REF1)as a local wound signal that regulates damage-triggered tissue repair and organ regeneration.This very finding may greatly expand opportunities for improving crop resilience through targeted bioengineering.
基金supported by the Key Project of Natural Science Foundation of Yunnan Province (202401AS070082)the National Natural Science Foundation of China (grants 32120103003 and 31970355)
文摘Rapid growth is an innovative trait of woody bamboos that has been widely studied.However,the genetic basis and evolution of this trait are poorly understood.Taking advantage of genomic resources of 11 representative bamboos at different ploidal levels,we integrated morphological,physiological,and transcriptomic datasets to investigate rapid growth.In particular,these bamboos include two large-sized and a small-sized woody species,compared with a diploid herbaceous species.Our results showed that gibberellin A1 was important for the rapid shoot growth of the world's largest bamboo,Dendrocalamus sinicus,and indicated that two gibberellins(GAs)-related genes,KAO and SLRL1,were key to the rapid shoot growth and culm size in woody bamboos.The expression of GAs-related genes exhibited significant subgenome asymmetry with subgenomes A and C demonstrating expression dominance in the large-sized woody bamboos while the generally submissive subgenomes B and D dominating in the small-sized species.The subgenome asymmetry was found to be correlated with the subgenome-specific gene structure,particularly UTRs and core promoters.Our study provides novel insights into the molecular mechanism and evolution of rapid shoot growth following allopolyploidization in woody bamboos,particularly via subgenome asymmetry.These findings are helpful for understanding of how polyploidization in general and subgenome asymmetry in particular contributed to the origin of innovative traits in plants.
基金supported by grants from the Biological Breeding-National Science and Technology Major Project(2024ZD04077)the National Natural Science Foundation of China(31801323)+1 种基金the Innovation Program of the Chinese Academy of Agricultural Sciencesthe Science and Technology Innovation Project of the Shandong Academy of Agricultural Sciences(CXGC2023F14)。
文摘Endodermal cells and starch-accumulating amyloplasts are well-known gravity sensors initiating shoot gravitropism in Arabidopsis thaliana.The transcription factors SHR and SGR1 regulate endodermal cell formation,while PGM has been demonstrated to regulate starch biosynthesis within chloroplasts,which eventually leads to starch accumulation in amyloplasts.However,the molecular mechanisms of gravity sensing in monocot shoots remain largely unexplored.In this study,we investigated the roles of these genes in rice(Oryza sativa),a model monocot,using CRISPR-Cas9 to generate single,double,and higher-order mutants.The rice genome harbors two orthologs each of SHR and SGR and a single ortholog of PGM.Our results revealed that single mutants of OsPGM,but not OsSHR or OsSGR,showed compromised shoot gravitropism.However,double mutants shr1shr2 and sgr1sgr2 displayed wider tiller angles and reduced gravity sensing,suggesting functional redundancy within each gene pair.Higher-order mutants exhibited progressively severe phenotypes,with quintuple mutants almost unresponsive to gravity stimulation.These findings suggest that these genes act additively through distinct but converging pathways in shoot gravitropism regulation.This study provides novel insights into the molecular mechanisms underlying gravity sensing in monocots and offers valuable knowledge for precision breeding to optimize rice architecture.
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.32330094,U21A20233,323B2057)the Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study(Grant No.SN-ZJUSIAS-0011).
文摘Plants undergo dynamic morphological changes in response to fluctuating light conditions.Despite significant progress in elucidating the mechanisms of light signal transduction,the precise influence of light on the development and regulation of shoot architecture remains a central research question.Studies focusing on model plants such as Arabidopsis thaliana and rice suggest light modulates shoot architecture through intricate regulatory networks.However,the molecular mechanisms governing the diverse effects of light on horticultural crops are still poorly understood.This review primarily focuses on horticultural crops,integrating research on model plants,including Arabidopsis and rice,to provide an overview of the regulatory mechanisms of light signals in plant architectural development.It also explores the prospects for manipulating light environments in greenhouse management strategies.
文摘Adoption of Chinese hybrid rice boosts food security in Madagascar As the sun rises over the rice paddies of Mahitsy,Ramos Rakotorinina breathes in the cool morning air,watching the emerald green shoots of Chinese hybrid rice sway softly in the breeze.
文摘Bean(Phaseolus vulgaris)is a globally important legume crop valued for its nutritional content and adaptability.Establishing a robust root system during early growth is critical for optimal nutrient uptake,shoot development,and increased resistance to biotic stress.This study evaluated the effects of exogenous indole-3-butyric acid(IBA)on root and shoot development in two bean cultivars,Onceler-98 and Topcu,during the seedling stage.IBA was applied at four concentrations:0(control),50,100,and 150μM.Morphological parameters measured included root length(RL),root fresh weight(RFW),root dry weight(RDW),root nodule number(RNN),shoot length(SL),shoot fresh weight(SFW),and shoot dry weight(SDW).The experiment followed a randomized complete block design with four replications.Significant(p≤0.05)and highly significant(p≤0.01)differences were observed across treatments and cultivars.The results indicated that Onceler-98 generally responded more favorably to IBA application,with optimal growth performance observed at 100μM.In contrast,Topcu was less responsive to IBA overall,and high concentrations-particularly 150μM-tended to suppress nodule formation.
文摘In November 2024,the famous British zoologist Jane Goodall,known as“the Mother of Chimpanzees”,visited China for the 17th time.During her trip,she celebrated the 30th anniversary of her“Roots&Shoots”project in China and participated in the 8th“It's Warm Winter”event organized by the Beijing It's Animal Protection Public Welfare Foundation(It's Fund).
基金supported by the Innovation Platform for Through Process Modeling and Simulation of Advanced Materials Processing Technologies(No.2012ZX04012011)the National Science Foundation of China(No.51575304)
文摘Core shooting process plays a decisive role in the quality of sand cores, and core box vents distribution is one of the most important factor determining the effectiveness of core shooting process. In this paper, the influence of core box vents distribution on the flow dynamics of core shooting process was investigated based on in situ experimental observations with transparent core box, high-speed camera and pressure measuring system. Attention was focused on the variation of both the flow behavior of sand and pressure curves due to different vents distribution. Taking both kinetic and frictional stress into account, a kinetic-frictional constitutive model was established to describe the internal momentum transfer in the solid phase. Two-fluid model(TFM) simulation was then performed and good agreement was achieved between the experimental and simulated results on both the flow behavior of sand and the pressure curves. It was found that vents distribution has direct effect on the pressure difference of different locations in the core box, which determines the buoyancy force exerting on the sand particles and significantly influences the filling process of core sand.
基金supported by the National Natural Science Foundation of China(7170120971771216)+1 种基金Shaanxi Natural Science Foundation(2019JQ-250)China Post-doctoral Fund(2019M653962)
文摘In order to cope with the increasing threat of the ballistic missile(BM)in a shorter reaction time,the shooting policy of the layered defense system needs to be optimized.The main decisionmaking problem of shooting optimization is how to choose the next BM which needs to be shot according to the previous engagements and results,thus maximizing the expected return of BMs killed or minimizing the cost of BMs penetration.Motivated by this,this study aims to determine an optimal shooting policy for a two-layer missile defense(TLMD)system.This paper considers a scenario in which the TLMD system wishes to shoot at a collection of BMs one at a time,and to maximize the return obtained from BMs killed before the system demise.To provide a policy analysis tool,this paper develops a general model for shooting decision-making,the shooting engagements can be described as a discounted reward Markov decision process.The index shooting policy is a strategy that can effectively balance the shooting returns and the risk that the defense mission fails,and the goal is to maximize the return obtained from BMs killed before the system demise.The numerical results show that the index policy is better than a range of competitors,especially the mean returns and the mean killing BM number.
