Over the past century,the safety of dams has gradually attracted attention from all parties.Research on the dynamic response and damage evolution of dams under extreme loads is the basis of dam safety issues.In recent...Over the past century,the safety of dams has gradually attracted attention from all parties.Research on the dynamic response and damage evolution of dams under extreme loads is the basis of dam safety issues.In recent decades,scholars have studied the responses of dams under earthquake loads,but there is still much room for improvement in experimental and theoretical research on small probability loads such as explosions.In this paper,a 50-m-high concrete gravity dam is used as a prototype dam,and a water explosion model test of a 2.5-m-high concrete gravity dam is designed.The water pressure and the acceleration response of the dam body in the test are analysed.The pressure characteristics and dynamic response of the dam body are assessed.Taking the dam damage test as an example,a numerical model of concrete gravity dam damage is established,and the damage evolution of the dam body is analysed.By combining experiments and numerical simulations,the damage characteristics of the dam body under the action of different charge water explosions are clarified.The integrity of the dam body is well maintained under the action of a small-quantity water explosion,and the dynamic response of the dam body is mainly caused by the shock wave.Both the shock wave and the bubble pulsation cause the dam body to accelerate,and the peak acceleration of the dam body under the action of the bubble pulsation is only one percent of the peak acceleration of the dam body under the action of the shock wave.When subjected to explosions in large quantities of water,the dam body is seriously damaged.Under the action of a shock wave,the dam body produces a secondary acceleration response,which is generated by an internal interaction after the dam body is damaged.The damage evolution process of the dam body under the action of a large-scale water explosion is analysed,and it is found that the shock wave pressure of the water explosion causes local damage to the dam body facing the explosion.After the peak value of the shock wave,the impulse continues to act on the dam body,causing cumulative damage and damage inside the dam body.展开更多
Point Sources and Gaussian beams are used frequently as fundamental building blocks for developing ultrasonic beam models. Both these models have different weaknesses that limit their effectiveness. Here, we will show...Point Sources and Gaussian beams are used frequently as fundamental building blocks for developing ultrasonic beam models. Both these models have different weaknesses that limit their effectiveness. Here, we will show that one can develop a Gaussian Beam Equivalent Point Source （GBEPS） model that removes those weaknesses and combines the accuracy and versatility of the point source models with much of the speed and well-behaved nature of Gaussian beam models. We will demonstrate the efficiency and versatility of this new GBEPS model in simulating the beams generated from ultrasonic phased arrays, using as few as one Gaussian beam per element of the array. A single element GBEPS model will be shown to be as accurate as a point source model even when substantial beam focusing or steering is present in the array or where the array beam is transmitted through an interface. At the same time the GBEPS model will be shown to be several orders of magnitude faster than the point source model.展开更多
How time flies!It has been the tenth anniversary since AMS started publishing in 1987.AMS(English edition)is an international academic journal in atmospheric sciences edited bythe Chinese Meteorological Society.During...How time flies!It has been the tenth anniversary since AMS started publishing in 1987.AMS(English edition)is an international academic journal in atmospheric sciences edited bythe Chinese Meteorological Society.During this period,ten volumes of AMS(41 Nos.,about500 articles)were published,including three special issues:on climate,on atmospheric signals展开更多
To meet the measurement demands on small-mass radiocarbon （carbon content at 10.6 g level） which are becoming increasingly significant, Xi＇an-AMS has made improvements to the existing method of sample loading and h...To meet the measurement demands on small-mass radiocarbon （carbon content at 10.6 g level） which are becoming increasingly significant, Xi＇an-AMS has made improvements to the existing method of sample loading and has upgraded the Cs sputter ion source from the original SO-110 model. In order to study the feasibility of small-mass samples in Xi＇an-AMS and evaluate the radiocarbon sample preparation ability using existing routine systems of H2/Fe and Zn/Fe, the small-mass samples prepared by four different methods are tested. They are the mass division method, mass dilution method, H2/Fe reduction method and Zn/Fe reduction method. The results show that carbon mass above 25 μg can be prepared using the existing Zn/Fe system, but no less than 100 μg is required using the existing H2/Fe system, which can be improved. This indicates Xi＇an-AMS are now able to analyze small-mass radiocarbon samples.展开更多
Given the scarcity of Satellite Frequency and Orbit(SFO)resources,it holds paramount importance to establish a comprehensive knowledge graph of SFO field(SFO-KG)and employ knowledge reasoning technology to automatical...Given the scarcity of Satellite Frequency and Orbit(SFO)resources,it holds paramount importance to establish a comprehensive knowledge graph of SFO field(SFO-KG)and employ knowledge reasoning technology to automatically mine available SFO resources.An essential aspect of constructing SFO-KG is the extraction of Chinese entity relations.Unfortunately,there is currently no publicly available Chinese SFO entity Relation Extraction(RE)dataset.Moreover,publicly available SFO text data contain numerous NA(representing for“No Answer”)relation category sentences that resemble other relation sentences and pose challenges in accurate classification,resulting in low recall and precision for the NA relation category in entity RE.Consequently,this issue adversely affects both the accuracy of constructing the knowledge graph and the efficiency of RE processes.To address these challenges,this paper proposes a method for extracting Chinese SFO text entity relations based on dynamic integrated learning.This method includes the construction of a manually annotated Chinese SFO entity RE dataset and a classifier combining features of SFO resource data.The proposed approach combines integrated learning and pre-training models,specifically utilizing Bidirectional Encoder Representation from Transformers(BERT).In addition,it incorporates one-class classification,attention mechanisms,and dynamic feedback mechanisms to improve the performance of the RE model.Experimental results show that the proposed method outperforms the traditional methods in terms of F1 value when extracting entity relations from both balanced and long-tailed datasets.展开更多
Recent studies have successfully demonstrated high-Tc superconductivity in bilayer nickelate La3Ni2O7.However,research on modulating the structural and transport characteristics of La3Ni2O7 films by applying“chemical...Recent studies have successfully demonstrated high-Tc superconductivity in bilayer nickelate La3Ni2O7.However,research on modulating the structural and transport characteristics of La3Ni2O7 films by applying“chemical”compressive pressure through cation substitution is still limited.Here,we address this issue in the La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,1.5,2.0,and 2.5)thin film samples.It was found that using Nd3+with a smaller radius instead of La3+can reduce the c-axis lattice constant and shift the metal-insulator transition(MIT)temperature TMIT.To probe the origin of the MIT at cryogenic temperatures,experimental measurements of magnetoresistance were conducted,and theoretical analysis was carried out using the Kondo model,Hikami-Larkin-Nagaoka equation,and other methods.The results indicate that as Nd doping rises,the contributions of the Kondo effect and two-dimensional weak localization(WL)first decrease and then increase.The total contribution of WL and the Kondo effect in the mid-doped La_(1.5)Nd_(1.5)Ni_(2)O_(7)sample was the smallest,which to some extent explains the changes in TMIT.The Kondo effect dominates in other La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,2.0,and 2.5)samples.This work demonstrates that cation doping has a significant impact on bilayer nickelates,providing experimental evidence for understanding the physical mechanism of the MIT in bilayer nickelates.展开更多
Background Coccidiosis,caused by Eimeria parasites,is a major enteric disease in poultry,significantly impacting animal health,production performance,and welfare.This disease imposes a substantial economic burden,cost...Background Coccidiosis,caused by Eimeria parasites,is a major enteric disease in poultry,significantly impacting animal health,production performance,and welfare.This disease imposes a substantial economic burden,costing the global poultry industry up to$13 billion annually.However,effective mitigation strategies for coccidiosis remain elusive.While different chicken breeds exhibit varying resistance to coccidiosis,no commensal bacteria have been directly linked to this resistance.Methods To assess relative resistance of different breeds to coccidiosis,10-day-old Fayoumi M5.1,Leghorn Ghs6,and Cobb chickens were challenged with 50,000 sporulated Eimeria maxima oocysts or mock-infected.Body weight changes,small intestinal lesions,and fecal oocyst shedding were evaluated on d 17.Ileal and cecal digesta were collected from individual animals on d 17 and subjected to microbiome analysis using 16S rRNA gene sequencing.Results Fayoumi M5.1 chickens showed the lowest growth retardation,intestinal lesion score,fecal oocyst shedding,and pathobiont proliferation compared to Ghs6 and Cobb chickens.The intestinal microbiota of M5.1 chickens also differed markedly from the other two breeds under both healthy and coccidiosis conditions.Notably,group A Lactobacillus and Ligilactobacillus salivarius were the least prevalent in both the ileum and cecum of healthy M5.1 chickens,but became highly enriched and comparable to Ghs6 and Cobb chickens in response to coccidiosis.Conversely,Weissella,Staphylococcus gallinarum,and Enterococcus durans/hirae were more abundant in the ileum of healthy M5.1 chickens than in the other two breeds.Despite being reduced by Eimeria,these bacteria retained higher abundance in M5.1 chickens compared to the other breeds.Conclusions Fayoumi M5.1 chickens exhibit greater resistance to coccidiosis than Leghorn Ghs6 layers and Cobb broilers.Several commensal bacteria,including group A Lactobacillus,L.salivarius,Weissella,S.gallinarum,and E.durans/hirae,are differentially enriched in Fayoumi M5.1 chickens with strong correlation with coccidiosis resistance.These bacteria hold potential as probiotics for coccidiosis mitigation.展开更多
Four new^(10)Be-^(26)Al isochron burial ages ranging from 4.4 to 2 Ma on ancestral Colorado River deposits in the lower Colorado River corridor(LCRC)help constrain the river’s evolution during the Pliocene and early ...Four new^(10)Be-^(26)Al isochron burial ages ranging from 4.4 to 2 Ma on ancestral Colorado River deposits in the lower Colorado River corridor(LCRC)help constrain the river’s evolution during the Pliocene and early Pleisto-cene.They help fill a gap between previous work that focused on older and younger deposits:Older dated deposits include the 5 Ma Bouse Formation,which records the integration of the Colorado River through a series of preexisting basins to the Gulf of California and the ca.4.5-3.5 Ma Bullhead Alluvium,a 200 to 300 m thick aggregational package that immediately followed integration.The much younger,100-70 ka,Chemehuevi Formation is another major aggrada-tion package mapped throughout the LCRC.The new burial ages on the facies of Santa Fe Railway(4.37±0.71 Ma),boulder conglomerate of Bat Cave Wash(2.12±0.26 and 2.05±0.31 Ma),and the Palo Verde alluvium(3.03±0.26 Ma)partially fill in a 3.5 M.y.gap between the deposition of the Bullhead Alluvium and the Chemeheuvi Formation and document the timescales over which the Colorado River was able to remove the Bullhead aggradational package and initiate newer and smaller aggradational pulses.展开更多
Understanding crash contributing factors is essential in safety management and improvement. These factors drive investment decisions, policies, regulations, and other safety-related initiatives. This paper analyzes fa...Understanding crash contributing factors is essential in safety management and improvement. These factors drive investment decisions, policies, regulations, and other safety-related initiatives. This paper analyzes factors that contribute to crash occurrence based on two national datasets in the United States (CISS and NASS-CDS) for the years 2017-2022 and 2010-2015, respectively. Three taxonomies were applied to enhance understanding of the various crash contributing factors. These taxonomies were developed based on previous research and practice and involved different groupings of human factors, vehicle factors, and roadway and environmental factors. Statistics for grouping the different types of factors and statistics for specific factors are provided. The results indicate that human factors are present in over 95% of crashes, roadway and environmental factors are present in over 45% of crashes, and vehicle factors are present in less than 2% of crashes. Regarding factors related to human error and vehicle maintenance, speeding is involved in over 25% of crashes, distraction is involved in over 20% of crashes, alcohol and drugs are involved in over 9% of crashes, and vehicle maintenance is involved in approximately 0.45% of crashes. Approximately 4.4% of crashes involve a driver who “looked but did not see.” Weather is involved in over 13% of crashes. Conclusions: The findings indicate that, consistent with previous research, human factors or human error are present in around 95% of crashes. Infrastructure and environmental factors contribute to about 45% of crashes. Vehicle factors contribute to only 1.67% - 1.71% of crashes. The results from this study could potentially be used to inform future safety management and improvement activities, including policy-making, regulation development, safe systems and systemic safety approaches to safety management, and other engineering, education, emergency response, enforcement, evaluation, and encouragement activities. The findings could also be used in the development of future Driver Assistance Technologies (DAT) systems and in enhancing existing technologies.展开更多
As drivers age, roadway conditions may become more challenging, particularly when normal aging is coupled with cognitive decline. Driving during lower visibility conditions, such as inclement weather, is especially ch...As drivers age, roadway conditions may become more challenging, particularly when normal aging is coupled with cognitive decline. Driving during lower visibility conditions, such as inclement weather, is especially challenging for older drivers due to their sensitivity to glare and reduced visibility. As a result, older drivers may adjust their behavior during adverse weather. This paper explores the differential impacts of weather on older drivers with cognitive decline compared to older drivers with normal cognitive function. Data were from a naturalistic driving study of older drivers in Omaha, Nebraska. Driver speed and weather data were extracted and the correlation between speed compliance, road weather conditions, and the cognitive/neurological status of the drivers was examined. Speed compliance was used as the surrogate safety measure since driving at lower speeds can indicate that the driver is challenged by roadway or environmental conditions and can therefore indicate a risk. The percentage of time during a trip when drivers were 16.1 kph under the speed limit was modeled as the dependent variable using beta regression. The variables that resulted in the best fit model were mild cognitive impairment (MCI), age group, traffic density, and weather. Results indicated that the youngest group of older drivers (young-old) spent less time driving at impeding speeds and had the least variability compared to the other two age groups. The middle group of older drivers (middle-old) had the highest amount of time driving at impeding speeds and had more variability than young-old drivers. The oldest group of older drivers (old-old) were the most likely to drive at impeding speeds and had the most variability. In general, older drivers were more likely to drive at impeding speeds during peak hours than during non-peak hours. Additionally, in most cases, older drivers spent less time below the speed limit when the weather was clear than in adverse conditions. Results indicate that older drivers are impacted by weather conditions, and distinct patterns were noted between older drivers who were cognitively impaired compared to drivers with normal cognition.展开更多
Defensin,an essential component of plant development,is indispensable in pathogen resistance.However,the molecular function of defensins under pathological conditions of Cytospora canker has not been characterized in ...Defensin,an essential component of plant development,is indispensable in pathogen resistance.However,the molecular function of defensins under pathological conditions of Cytospora canker has not been characterized in apple plants.The present study exhibits a detailed overview of the phylogeny and structure of 29 defensins(MdDEF)in apple.Expression analysis revealed that MdDEF genes were spatiotemporally diverse across apple tissues.Five MdDEF genes were found to be significantly up-regulated following a challenge with Cytospora mali.The transgenic overexpression of five defensin genes in apple calli enhanced resistance to C.mali.Among them,MdDEF30 was strongly induced and conferred the highest resistance level in vivo.Meanwhile,antifungal activity assays in vitro demonstrated that a recombinant protein produced from MdDEF30could inhibit the growth of C.mali.Notably,MdDEF30 promoted the accumulation of reactive oxygen species(ROS)and activated defense-related genes such as PR4,PR10,CML13,and MPK3.Co-expression regulatory network analysis showed that MdWRKY75 may regulate the expression of MdDEF30.Further yeast onehybrid(Y1H),luciferase,and chromatin Immunoprecipitation quantitative polymerase chain reaction(ChIPqPCR)assays verified that MdWRKY75 could directly bind to the promoter of MdDEF30.Importantly,pathogen inoculation assays confirmed that MdWRKY75 positively regulates resistance by transcriptionally activating MdDEF30.Overall,these results demonstrated that MdDEF30 promotes resistance to C.mali in apple plants and that MdWRKY75 regulates MdDEF30 expression during the induction of resistance,thereby clarifying biochemical mechanisms of resistance to C.mali in apple trees.展开更多
Physical layer security methods based on joint relay and jammer selection(JRJS)have been widely investigated in the study of secure wireless communications.Different from current works on JRJS schemes,which assumed th...Physical layer security methods based on joint relay and jammer selection(JRJS)have been widely investigated in the study of secure wireless communications.Different from current works on JRJS schemes,which assumed that the global channel state information(CSI)of the eavesdroppers(Eves)was known beforehand,then the optimal relaying and jamming relays were determined.More importantly,the time complexity of selecting optimal jamming relay is O(N^(2)),where N is the maximum number of relays/Eves.In this paper,for the scenario where the source wants to exchange the message with the destination,via relaying scheme due to longer communication distance and limited transmission power,in the presence of multiple Eves,with the assumption of Eves'perfect CSI and average CSI,we propose two kinds of JRJS methods.In particular,the time complexity of finding the optimal jammer can be reduced to O(N).Furthermore,we present a novel JRJS scheme for no CSI of Eves by minimizing the difference between expected signal and interfering signal at the destination.Finally,simulations show that the designed methods are more effective than JRJS and other existing strategies in terms of security performance.展开更多
Theoretically,a twinning dislocation must stay on the twinning plane which is the first invariant plane of a twinning mode,because the glide of twinning dislocation linearly transforms the parent lattice to the twin l...Theoretically,a twinning dislocation must stay on the twinning plane which is the first invariant plane of a twinning mode,because the glide of twinning dislocation linearly transforms the parent lattice to the twin lattice.However,recent experimental observations showed that a{1011}{1012}twin variant could cross another variant during twin-twin interaction.It is well known that{1011}twinning is mediated by zonal twinning dislocations.Thus,how the zonal twinning dislocations transmute during twin-twin interaction is of great interest but not well understood.In this work,atomistic simulation is performed to investigate interaction between{1011}twin variants.Our results show that when an incoming twin variant impinges on the other which acts as a barrier,surprisingly,the barrier twin can grow at the expense of the incoming twin.Eventually one variant consumes the other.Structural analysis shows that the twinning dislocations of the barrier variant are able to penetrate the zone of twin-twin intersection,by plowing through the lattice of one variant and transform its lattice into the lattice of the other.Careful lattice correspondence analysis reveals that,the lattice transformation from one variant to the other is close to{1012}{1011}twinning,but the orientation relationship deviates by a minor lattice rotation.This deviation presents a significant energy barrier to the lattice transformation,and thus it is expected such a twin-twin interaction will increase the stress for twin growth.展开更多
Integrating mobile edge computing (MEC) and digital twin (DT) technologies to enhance network performance through predictive, adaptive control for energy-efficient and low-latency communication is a significant challe...Integrating mobile edge computing (MEC) and digital twin (DT) technologies to enhance network performance through predictive, adaptive control for energy-efficient and low-latency communication is a significant challenge. This paper presents the EcoEdgeTwin model, an innovative framework that harnesses the harmony between MEC and DT technologies to ensure an efficient network operation. We optimise the utility function to balance enhancing users' quality of experience (QoE) and minimising latency and energy consumption at edge servers. This approach ensures efficient and adaptable network operations, utilising DT to synchronise and integrate real-time data seamlessly. Our framework implements robust mechanisms for task offloading, service caching and cost-effective service migration. Additionally, it manages energy consumption related to task processing, communication and the influence of DT predictions, all essential for optimising latency and minimising energy usage. Through the utility model, we also prioritise QoE, fostering a user-centric approach to network management that balances network efficiency with user satisfaction. A cornerstone of our approach is integrating the advantage actor-critic algorithm, marking a pioneering use of deep reinforcement learning for dynamic network management. This strategy addresses challenges in service mobility and network variability, ensuring optimal network performance matrices. Our extensive simulations demonstrate that compared to benchmark models, the EcoEdgeTwin framework significantly reduces energy usage and latency while enhancing QoE.展开更多
In-situ high-resolution transmission electron microscopy(HRTEM)is performed to investigate the de-formation behavior of hexagonal close-packed rhenium(Re)which is compressed along the{1-100}di-rection.Atomistic simula...In-situ high-resolution transmission electron microscopy(HRTEM)is performed to investigate the de-formation behavior of hexagonal close-packed rhenium(Re)which is compressed along the{1-100}di-rection.Atomistic simulations are also conducted to better understand the deformation mechanisms.Two types of lattice reorientation are observed during compression.The first type involves the reori-entation of one lattice by∼90°around{11-20},which is accomplished by the formation of an interme-diate face-center-cubic(FCC)phase at the interface.This transformation sequence can be described as{1-100}matrix→{111}FCC→(0001)twin.In the second type,a new grain is formed but does not satisfy any known twin relationship with the matrix,and an intermediate FCC phase is also formed.The transfor-mation sequence can be described as{1¯101}matrix→{111}FCC→(0001)grain.Mechanisms responsible for the observed lattice reorientation and sequential phase transitions are analyzed by conducting lattice correspondence analyses on the simulation results.Strain accommodation is also analyzed to explain the mechanisms for lattice reorientation and the intermediate phase transformations.The results provide new insight into the deformation behavior of HCP metals.展开更多
文摘Over the past century,the safety of dams has gradually attracted attention from all parties.Research on the dynamic response and damage evolution of dams under extreme loads is the basis of dam safety issues.In recent decades,scholars have studied the responses of dams under earthquake loads,but there is still much room for improvement in experimental and theoretical research on small probability loads such as explosions.In this paper,a 50-m-high concrete gravity dam is used as a prototype dam,and a water explosion model test of a 2.5-m-high concrete gravity dam is designed.The water pressure and the acceleration response of the dam body in the test are analysed.The pressure characteristics and dynamic response of the dam body are assessed.Taking the dam damage test as an example,a numerical model of concrete gravity dam damage is established,and the damage evolution of the dam body is analysed.By combining experiments and numerical simulations,the damage characteristics of the dam body under the action of different charge water explosions are clarified.The integrity of the dam body is well maintained under the action of a small-quantity water explosion,and the dynamic response of the dam body is mainly caused by the shock wave.Both the shock wave and the bubble pulsation cause the dam body to accelerate,and the peak acceleration of the dam body under the action of the bubble pulsation is only one percent of the peak acceleration of the dam body under the action of the shock wave.When subjected to explosions in large quantities of water,the dam body is seriously damaged.Under the action of a shock wave,the dam body produces a secondary acceleration response,which is generated by an internal interaction after the dam body is damaged.The damage evolution process of the dam body under the action of a large-scale water explosion is analysed,and it is found that the shock wave pressure of the water explosion causes local damage to the dam body facing the explosion.After the peak value of the shock wave,the impulse continues to act on the dam body,causing cumulative damage and damage inside the dam body.
基金supported by the National Science Foundation Industry/University Cooperative Research Center program at Iowa State Universitythe Natural Sciences and Engineering Research Council of Canadaby the National Natural Science Foundation of China(NSFC)
文摘Point Sources and Gaussian beams are used frequently as fundamental building blocks for developing ultrasonic beam models. Both these models have different weaknesses that limit their effectiveness. Here, we will show that one can develop a Gaussian Beam Equivalent Point Source （GBEPS） model that removes those weaknesses and combines the accuracy and versatility of the point source models with much of the speed and well-behaved nature of Gaussian beam models. We will demonstrate the efficiency and versatility of this new GBEPS model in simulating the beams generated from ultrasonic phased arrays, using as few as one Gaussian beam per element of the array. A single element GBEPS model will be shown to be as accurate as a point source model even when substantial beam focusing or steering is present in the array or where the array beam is transmitted through an interface. At the same time the GBEPS model will be shown to be several orders of magnitude faster than the point source model.
文摘How time flies!It has been the tenth anniversary since AMS started publishing in 1987.AMS(English edition)is an international academic journal in atmospheric sciences edited bythe Chinese Meteorological Society.During this period,ten volumes of AMS(41 Nos.,about500 articles)were published,including three special issues:on climate,on atmospheric signals
基金Supported by National Natural Science Foundation of China(11205161,41290254)
文摘To meet the measurement demands on small-mass radiocarbon （carbon content at 10.6 g level） which are becoming increasingly significant, Xi＇an-AMS has made improvements to the existing method of sample loading and has upgraded the Cs sputter ion source from the original SO-110 model. In order to study the feasibility of small-mass samples in Xi＇an-AMS and evaluate the radiocarbon sample preparation ability using existing routine systems of H2/Fe and Zn/Fe, the small-mass samples prepared by four different methods are tested. They are the mass division method, mass dilution method, H2/Fe reduction method and Zn/Fe reduction method. The results show that carbon mass above 25 μg can be prepared using the existing Zn/Fe system, but no less than 100 μg is required using the existing H2/Fe system, which can be improved. This indicates Xi＇an-AMS are now able to analyze small-mass radiocarbon samples.
文摘Given the scarcity of Satellite Frequency and Orbit(SFO)resources,it holds paramount importance to establish a comprehensive knowledge graph of SFO field(SFO-KG)and employ knowledge reasoning technology to automatically mine available SFO resources.An essential aspect of constructing SFO-KG is the extraction of Chinese entity relations.Unfortunately,there is currently no publicly available Chinese SFO entity Relation Extraction(RE)dataset.Moreover,publicly available SFO text data contain numerous NA(representing for“No Answer”)relation category sentences that resemble other relation sentences and pose challenges in accurate classification,resulting in low recall and precision for the NA relation category in entity RE.Consequently,this issue adversely affects both the accuracy of constructing the knowledge graph and the efficiency of RE processes.To address these challenges,this paper proposes a method for extracting Chinese SFO text entity relations based on dynamic integrated learning.This method includes the construction of a manually annotated Chinese SFO entity RE dataset and a classifier combining features of SFO resource data.The proposed approach combines integrated learning and pre-training models,specifically utilizing Bidirectional Encoder Representation from Transformers(BERT).In addition,it incorporates one-class classification,attention mechanisms,and dynamic feedback mechanisms to improve the performance of the RE model.Experimental results show that the proposed method outperforms the traditional methods in terms of F1 value when extracting entity relations from both balanced and long-tailed datasets.
基金supported by the Natural Science Foundation of Guangdong Province of China(Grant No.2025A1515011071)the National Natural Science Foundation of China(Grant Nos.92065110,11974048,and 12074334)the Beijing Municipal Natural Science Foundation Key Research Topics(Grant No.Z230006)。
文摘Recent studies have successfully demonstrated high-Tc superconductivity in bilayer nickelate La3Ni2O7.However,research on modulating the structural and transport characteristics of La3Ni2O7 films by applying“chemical”compressive pressure through cation substitution is still limited.Here,we address this issue in the La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,1.5,2.0,and 2.5)thin film samples.It was found that using Nd3+with a smaller radius instead of La3+can reduce the c-axis lattice constant and shift the metal-insulator transition(MIT)temperature TMIT.To probe the origin of the MIT at cryogenic temperatures,experimental measurements of magnetoresistance were conducted,and theoretical analysis was carried out using the Kondo model,Hikami-Larkin-Nagaoka equation,and other methods.The results indicate that as Nd doping rises,the contributions of the Kondo effect and two-dimensional weak localization(WL)first decrease and then increase.The total contribution of WL and the Kondo effect in the mid-doped La_(1.5)Nd_(1.5)Ni_(2)O_(7)sample was the smallest,which to some extent explains the changes in TMIT.The Kondo effect dominates in other La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,2.0,and 2.5)samples.This work demonstrates that cation doping has a significant impact on bilayer nickelates,providing experimental evidence for understanding the physical mechanism of the MIT in bilayer nickelates.
基金funded by the USDA National Institute of Food and Agriculture grants(2022-67016-37208 and 2024-67016-42415)the Ralph F.and Leila W.Boulware Endowment Fund,Oklahoma Agricultural Experiment Station Project H-3268+1 种基金Iowa Agriculture and Home Economics Experiment Station Project IOW05620supported by two separate USDA National Institute of Food and Agriculture Predoctoral Fellowship grants(2024-67011-42944 and 2021-67034-35184).
文摘Background Coccidiosis,caused by Eimeria parasites,is a major enteric disease in poultry,significantly impacting animal health,production performance,and welfare.This disease imposes a substantial economic burden,costing the global poultry industry up to$13 billion annually.However,effective mitigation strategies for coccidiosis remain elusive.While different chicken breeds exhibit varying resistance to coccidiosis,no commensal bacteria have been directly linked to this resistance.Methods To assess relative resistance of different breeds to coccidiosis,10-day-old Fayoumi M5.1,Leghorn Ghs6,and Cobb chickens were challenged with 50,000 sporulated Eimeria maxima oocysts or mock-infected.Body weight changes,small intestinal lesions,and fecal oocyst shedding were evaluated on d 17.Ileal and cecal digesta were collected from individual animals on d 17 and subjected to microbiome analysis using 16S rRNA gene sequencing.Results Fayoumi M5.1 chickens showed the lowest growth retardation,intestinal lesion score,fecal oocyst shedding,and pathobiont proliferation compared to Ghs6 and Cobb chickens.The intestinal microbiota of M5.1 chickens also differed markedly from the other two breeds under both healthy and coccidiosis conditions.Notably,group A Lactobacillus and Ligilactobacillus salivarius were the least prevalent in both the ileum and cecum of healthy M5.1 chickens,but became highly enriched and comparable to Ghs6 and Cobb chickens in response to coccidiosis.Conversely,Weissella,Staphylococcus gallinarum,and Enterococcus durans/hirae were more abundant in the ileum of healthy M5.1 chickens than in the other two breeds.Despite being reduced by Eimeria,these bacteria retained higher abundance in M5.1 chickens compared to the other breeds.Conclusions Fayoumi M5.1 chickens exhibit greater resistance to coccidiosis than Leghorn Ghs6 layers and Cobb broilers.Several commensal bacteria,including group A Lactobacillus,L.salivarius,Weissella,S.gallinarum,and E.durans/hirae,are differentially enriched in Fayoumi M5.1 chickens with strong correlation with coccidiosis resistance.These bacteria hold potential as probiotics for coccidiosis mitigation.
文摘Four new^(10)Be-^(26)Al isochron burial ages ranging from 4.4 to 2 Ma on ancestral Colorado River deposits in the lower Colorado River corridor(LCRC)help constrain the river’s evolution during the Pliocene and early Pleisto-cene.They help fill a gap between previous work that focused on older and younger deposits:Older dated deposits include the 5 Ma Bouse Formation,which records the integration of the Colorado River through a series of preexisting basins to the Gulf of California and the ca.4.5-3.5 Ma Bullhead Alluvium,a 200 to 300 m thick aggregational package that immediately followed integration.The much younger,100-70 ka,Chemehuevi Formation is another major aggrada-tion package mapped throughout the LCRC.The new burial ages on the facies of Santa Fe Railway(4.37±0.71 Ma),boulder conglomerate of Bat Cave Wash(2.12±0.26 and 2.05±0.31 Ma),and the Palo Verde alluvium(3.03±0.26 Ma)partially fill in a 3.5 M.y.gap between the deposition of the Bullhead Alluvium and the Chemeheuvi Formation and document the timescales over which the Colorado River was able to remove the Bullhead aggradational package and initiate newer and smaller aggradational pulses.
文摘Understanding crash contributing factors is essential in safety management and improvement. These factors drive investment decisions, policies, regulations, and other safety-related initiatives. This paper analyzes factors that contribute to crash occurrence based on two national datasets in the United States (CISS and NASS-CDS) for the years 2017-2022 and 2010-2015, respectively. Three taxonomies were applied to enhance understanding of the various crash contributing factors. These taxonomies were developed based on previous research and practice and involved different groupings of human factors, vehicle factors, and roadway and environmental factors. Statistics for grouping the different types of factors and statistics for specific factors are provided. The results indicate that human factors are present in over 95% of crashes, roadway and environmental factors are present in over 45% of crashes, and vehicle factors are present in less than 2% of crashes. Regarding factors related to human error and vehicle maintenance, speeding is involved in over 25% of crashes, distraction is involved in over 20% of crashes, alcohol and drugs are involved in over 9% of crashes, and vehicle maintenance is involved in approximately 0.45% of crashes. Approximately 4.4% of crashes involve a driver who “looked but did not see.” Weather is involved in over 13% of crashes. Conclusions: The findings indicate that, consistent with previous research, human factors or human error are present in around 95% of crashes. Infrastructure and environmental factors contribute to about 45% of crashes. Vehicle factors contribute to only 1.67% - 1.71% of crashes. The results from this study could potentially be used to inform future safety management and improvement activities, including policy-making, regulation development, safe systems and systemic safety approaches to safety management, and other engineering, education, emergency response, enforcement, evaluation, and encouragement activities. The findings could also be used in the development of future Driver Assistance Technologies (DAT) systems and in enhancing existing technologies.
文摘As drivers age, roadway conditions may become more challenging, particularly when normal aging is coupled with cognitive decline. Driving during lower visibility conditions, such as inclement weather, is especially challenging for older drivers due to their sensitivity to glare and reduced visibility. As a result, older drivers may adjust their behavior during adverse weather. This paper explores the differential impacts of weather on older drivers with cognitive decline compared to older drivers with normal cognitive function. Data were from a naturalistic driving study of older drivers in Omaha, Nebraska. Driver speed and weather data were extracted and the correlation between speed compliance, road weather conditions, and the cognitive/neurological status of the drivers was examined. Speed compliance was used as the surrogate safety measure since driving at lower speeds can indicate that the driver is challenged by roadway or environmental conditions and can therefore indicate a risk. The percentage of time during a trip when drivers were 16.1 kph under the speed limit was modeled as the dependent variable using beta regression. The variables that resulted in the best fit model were mild cognitive impairment (MCI), age group, traffic density, and weather. Results indicated that the youngest group of older drivers (young-old) spent less time driving at impeding speeds and had the least variability compared to the other two age groups. The middle group of older drivers (middle-old) had the highest amount of time driving at impeding speeds and had more variability than young-old drivers. The oldest group of older drivers (old-old) were the most likely to drive at impeding speeds and had the most variability. In general, older drivers were more likely to drive at impeding speeds during peak hours than during non-peak hours. Additionally, in most cases, older drivers spent less time below the speed limit when the weather was clear than in adverse conditions. Results indicate that older drivers are impacted by weather conditions, and distinct patterns were noted between older drivers who were cognitively impaired compared to drivers with normal cognition.
基金funded by the National Key R&D Program of China(2023YFD1401401)the China Agriculture Research System(CARS27)。
文摘Defensin,an essential component of plant development,is indispensable in pathogen resistance.However,the molecular function of defensins under pathological conditions of Cytospora canker has not been characterized in apple plants.The present study exhibits a detailed overview of the phylogeny and structure of 29 defensins(MdDEF)in apple.Expression analysis revealed that MdDEF genes were spatiotemporally diverse across apple tissues.Five MdDEF genes were found to be significantly up-regulated following a challenge with Cytospora mali.The transgenic overexpression of five defensin genes in apple calli enhanced resistance to C.mali.Among them,MdDEF30 was strongly induced and conferred the highest resistance level in vivo.Meanwhile,antifungal activity assays in vitro demonstrated that a recombinant protein produced from MdDEF30could inhibit the growth of C.mali.Notably,MdDEF30 promoted the accumulation of reactive oxygen species(ROS)and activated defense-related genes such as PR4,PR10,CML13,and MPK3.Co-expression regulatory network analysis showed that MdWRKY75 may regulate the expression of MdDEF30.Further yeast onehybrid(Y1H),luciferase,and chromatin Immunoprecipitation quantitative polymerase chain reaction(ChIPqPCR)assays verified that MdWRKY75 could directly bind to the promoter of MdDEF30.Importantly,pathogen inoculation assays confirmed that MdWRKY75 positively regulates resistance by transcriptionally activating MdDEF30.Overall,these results demonstrated that MdDEF30 promotes resistance to C.mali in apple plants and that MdWRKY75 regulates MdDEF30 expression during the induction of resistance,thereby clarifying biochemical mechanisms of resistance to C.mali in apple trees.
基金supported by the National Natural Science Foundation of China with Grants 62301076 and 62321001。
文摘Physical layer security methods based on joint relay and jammer selection(JRJS)have been widely investigated in the study of secure wireless communications.Different from current works on JRJS schemes,which assumed that the global channel state information(CSI)of the eavesdroppers(Eves)was known beforehand,then the optimal relaying and jamming relays were determined.More importantly,the time complexity of selecting optimal jamming relay is O(N^(2)),where N is the maximum number of relays/Eves.In this paper,for the scenario where the source wants to exchange the message with the destination,via relaying scheme due to longer communication distance and limited transmission power,in the presence of multiple Eves,with the assumption of Eves'perfect CSI and average CSI,we propose two kinds of JRJS methods.In particular,the time complexity of finding the optimal jammer can be reduced to O(N).Furthermore,we present a novel JRJS scheme for no CSI of Eves by minimizing the difference between expected signal and interfering signal at the destination.Finally,simulations show that the designed methods are more effective than JRJS and other existing strategies in terms of security performance.
基金support from U.S.National Science Foundation(NSF)(CMMI-2016263,2032483).
文摘Theoretically,a twinning dislocation must stay on the twinning plane which is the first invariant plane of a twinning mode,because the glide of twinning dislocation linearly transforms the parent lattice to the twin lattice.However,recent experimental observations showed that a{1011}{1012}twin variant could cross another variant during twin-twin interaction.It is well known that{1011}twinning is mediated by zonal twinning dislocations.Thus,how the zonal twinning dislocations transmute during twin-twin interaction is of great interest but not well understood.In this work,atomistic simulation is performed to investigate interaction between{1011}twin variants.Our results show that when an incoming twin variant impinges on the other which acts as a barrier,surprisingly,the barrier twin can grow at the expense of the incoming twin.Eventually one variant consumes the other.Structural analysis shows that the twinning dislocations of the barrier variant are able to penetrate the zone of twin-twin intersection,by plowing through the lattice of one variant and transform its lattice into the lattice of the other.Careful lattice correspondence analysis reveals that,the lattice transformation from one variant to the other is close to{1012}{1011}twinning,but the orientation relationship deviates by a minor lattice rotation.This deviation presents a significant energy barrier to the lattice transformation,and thus it is expected such a twin-twin interaction will increase the stress for twin growth.
文摘Integrating mobile edge computing (MEC) and digital twin (DT) technologies to enhance network performance through predictive, adaptive control for energy-efficient and low-latency communication is a significant challenge. This paper presents the EcoEdgeTwin model, an innovative framework that harnesses the harmony between MEC and DT technologies to ensure an efficient network operation. We optimise the utility function to balance enhancing users' quality of experience (QoE) and minimising latency and energy consumption at edge servers. This approach ensures efficient and adaptable network operations, utilising DT to synchronise and integrate real-time data seamlessly. Our framework implements robust mechanisms for task offloading, service caching and cost-effective service migration. Additionally, it manages energy consumption related to task processing, communication and the influence of DT predictions, all essential for optimising latency and minimising energy usage. Through the utility model, we also prioritise QoE, fostering a user-centric approach to network management that balances network efficiency with user satisfaction. A cornerstone of our approach is integrating the advantage actor-critic algorithm, marking a pioneering use of deep reinforcement learning for dynamic network management. This strategy addresses challenges in service mobility and network variability, ensuring optimal network performance matrices. Our extensive simulations demonstrate that compared to benchmark models, the EcoEdgeTwin framework significantly reduces energy usage and latency while enhancing QoE.
基金support from No.NSF CMMI 1536811 through the University of PittsburghC.M.W.was supported by the PNNL LDRD program.Bin Li thanks for the support from Nos.NSF CMMI 1635088,2016263,and 2032483+1 种基金This work was performed,in part,at the William R.Wiley Environmental Molecular Sciences Laboratory,a national scientific user facility sponsored by the U.S.Department of Energy,Office of Biological and Environmental Research,and located at PNNLPNNL is operated by Battelle for the U.S.Department of Energy under contract No.DE-AC05-76RLO1830.
文摘In-situ high-resolution transmission electron microscopy(HRTEM)is performed to investigate the de-formation behavior of hexagonal close-packed rhenium(Re)which is compressed along the{1-100}di-rection.Atomistic simulations are also conducted to better understand the deformation mechanisms.Two types of lattice reorientation are observed during compression.The first type involves the reori-entation of one lattice by∼90°around{11-20},which is accomplished by the formation of an interme-diate face-center-cubic(FCC)phase at the interface.This transformation sequence can be described as{1-100}matrix→{111}FCC→(0001)twin.In the second type,a new grain is formed but does not satisfy any known twin relationship with the matrix,and an intermediate FCC phase is also formed.The transfor-mation sequence can be described as{1¯101}matrix→{111}FCC→(0001)grain.Mechanisms responsible for the observed lattice reorientation and sequential phase transitions are analyzed by conducting lattice correspondence analyses on the simulation results.Strain accommodation is also analyzed to explain the mechanisms for lattice reorientation and the intermediate phase transformations.The results provide new insight into the deformation behavior of HCP metals.
