Timely and reliable estimation of regional crop yield is a vital component of food security assessment, especially in developing regions. The traditional crop forecasting methods need ample time and labor to collect a...Timely and reliable estimation of regional crop yield is a vital component of food security assessment, especially in developing regions. The traditional crop forecasting methods need ample time and labor to collect and process field data to release official yield reports. Satellite remote sensing data is considered a cost-effective and accurate way of predicting crop yield at pixel-level. In this study, maximum Enhanced Vegetation Index (EVI) during the crop-growing season was integrated with Machine Learning Regression (MLR) models to estimate wheat and rice yields in Pakistan’s Punjab province. Five MLR models were compared using a fivefold cross-validation method for their predictive accuracy. The study results revealed that the regression model based on the Gaussian process outperformed over other models. The best performing model attained coefficient of determination (R^(2)), Root Mean Square Error (RMSE, t/ ha), and Mean Absolute Error (MAE, t/ha) of 0.75, 0.281, and 0.236 for wheat;0.68, 0.112, and 0.091 for rice, respectively. The proposed method made it feasible to predict wheat and rice 6- 8 weeks before the harvest. The early prediction of crop yield and its spatial distribution in the region can help formulate efficient agricultural policies for sustainable social, environmental, and economic progress.展开更多
Quorum systems have been used to solve the problem of data consistency in distributed fault-tolerance systems.But when intrusions occur,traditional quorum systems have some disadvantages.For example,synchronous quorum...Quorum systems have been used to solve the problem of data consistency in distributed fault-tolerance systems.But when intrusions occur,traditional quorum systems have some disadvantages.For example,synchronous quorum systems are subject to DOS attacks,while asynchronous quorum systems need a larger system size(at least 3f+1 for generic data,and f fewer for self-verifying data).In order to solve the problems above,an intrusion-tolerance quorum system(ITQS)of hybrid time model based on trust timely computing base is presented(TTCB).The TTCB is a trust secure real-time component inside the server with a well defined interface and separated from the operation system.It is in the synchronous communication environment while the application layer in the server deals with read-write requests and executes update-copy protocols asynchronously.The architectural hybridization of synchrony and asynchrony can achieve the data consistency and availability correctly.We also build two kinds of ITQSes based on TTCB,i.e.,the symmetrical and the asymmetrical TTCB quorum systems.In the performance evaluations,we show that TTCB quorum systems are of smaller size,lower load and higher availability.展开更多
Background: Ensuring prompt diagnosis and timely malaria treatment will prevent most cases of uncomplicated malaria from progressing to severe and fatal illness. To avoid this progression, treatment must begin as soon...Background: Ensuring prompt diagnosis and timely malaria treatment will prevent most cases of uncomplicated malaria from progressing to severe and fatal illness. To avoid this progression, treatment must begin as soon as possible, generally within 24 hours after symptoms onset. The reason why mothers/caretakers delay in malaria prompt diagnosis and timely treatment for under-five is not well studied in the study area as well as in Ethiopia. Objective: To assess determinants of delay in malaria prompt diagnosis and timely treatment among under-five children in Shashogo Woreda, Hadiya Zone, Southern Ethiopia, 2013. Methods: An unmatched case control study was conducted from March 25-April 25, 2013. A total sample size of 302 with 151 cases and 151 controls were selected by systematic random sampling techniques. Cases were under-five children who had clinical malaria and sought treatment after 24 hours of symptoms onset, and controls were under-five children who had clinical malaria and sought treatment within 24 hours of symptoms onset. Both bivariate and multivariate logistic regressions were done to identify determinant of delay in malaria prompt diagnosis and timely treatment. Results: A total of 151 mothers/caretakers of cases and 151 mothers/caretakers of controls were interviewed. Illiterate mothers (AOR = 7.14;95%CI: 1.10, 46.39), monthly income ≤500 ETB (AOR = 5.49;95%CI: 2.09, 14.45), females sex (AOR = 3.45;95%CI: 1.62, 7.34), distance from health facility >5 km (AOR = 4.31;95%CI: 1.22, 15.23), absence of history of child death (AOR = 4.21;95%CI: 1.514, 11.68), side effects of antimalarial drugs (AOR = 2.91;95%CI: 1.15, 7.33) and khat chewing (AOR = 2.38;95%CI: 1.28, 5.79) were determinants of delay in malaria prompt diagnosis and timely treatment of under-five children. Conclusion: Mother’s education, monthly income, distance from health facility, absence of history of child death, complained about side effects of drugs and khat chewing were predictors of delay of prompt diagnosis and timely malaria treatment. Effective malaria control programs revision would be required to avoid delay of prompt diagnosis and timely treatment for under-five children.展开更多
In recent years,significant breakthroughs have been achieved in the exploration of deep volcanic rocks in the Junggar Basin,highlighting their substantial exploration potential.The complex distribution of volcanic res...In recent years,significant breakthroughs have been achieved in the exploration of deep volcanic rocks in the Junggar Basin,highlighting their substantial exploration potential.The complex distribution of volcanic reservoirs is attributed to the multi-phase tectonic evolution within the basin,with their superior reservoir properties playing a crucial role in natural gas formation.However,due to the combined effects of multi-cyclic volcanic eruptions and tectonic activities,predicting volcanic facies distribution and favorable reservoirs remains highly challenging.This study focuses on the third member of the Jiamuhe Formation in the Zhongguai Uplift.By integrating drilling and petrophysical data with well-seismic analysis techniques,a seismic identification model for volcanic reservoirs has been established.The findings reveal that different facies exhibit distinct seismic response characteristics.Andesite,rhyolite,volcanic breccia,and volcanic clastic rocks show variability in amplitude,frequency,and continuity.Using structural-guided filtering,high-resolution coherence analysis,and 3D body carving techniques,the locations of volcanic craters and eruption centers were successfully identified,further clarifying the distribution patterns of volcanic facies.By combining multi-attribute clustering analysis and seismic attribute extraction,a volcanic facies zone distribution map was generated,and favorable exploration directions for volcanic reservoirs were proposed.The study provides technical guidance for the exploration of deep volcanic oil and gas reservoirs in the Junggar Basin and holds significant application value.展开更多
Ideally,firms should discontinue projects that become unprofitable.Managers,however,continue to operate such projects because of their limited employment horizons and empire-building motivations(Jensen,1986; Ball,2001...Ideally,firms should discontinue projects that become unprofitable.Managers,however,continue to operate such projects because of their limited employment horizons and empire-building motivations(Jensen,1986; Ball,2001).Prior studies suggest that timely loss recognition in accounting earnings enables lenders,shareholders,and boards of directors to identify unprofitable projects; thereby,enabling them to force managers to discontinue such projects before large value erosion occurs.However,this conjecture has not been tested empirically.Consistent with this notion,we find that timely loss recognition increases the likelihood of timely closures of unprofitable projects.Moreover,managers,by announcing late discontinuations of such projects,reveal their inability to select good projects and/or to contain losses,when projects turn unprofitable.Accordingly,thereafter,the fund providers and board of directors are likely to demand improved timeliness of loss recognition and stringent scrutiny of firms' capital expenditure plans.Consistently,we find that firms that announce large discontinuation losses reduce capital expenditures and improve timeliness of loss recognition in subsequent years.Our study provides evidence that timely loss reporting affects "real" economic decisions and creates economic benefits.展开更多
After spinal cord injury,impairment of the sensorimotor circuit can lead to dysfunction in the motor,sensory,proprioceptive,and autonomic nervous systems.Functional recovery is often hindered by constraints on the tim...After spinal cord injury,impairment of the sensorimotor circuit can lead to dysfunction in the motor,sensory,proprioceptive,and autonomic nervous systems.Functional recovery is often hindered by constraints on the timing of interventions,combined with the limitations of current methods.To address these challenges,various techniques have been developed to aid in the repair and reconstruction of neural circuits at different stages of injury.Notably,neuromodulation has garnered considerable attention for its potential to enhance nerve regeneration,provide neuroprotection,restore neurons,and regulate the neural reorganization of circuits within the cerebral cortex and corticospinal tract.To improve the effectiveness of these interventions,the implementation of multitarget early interventional neuromodulation strategies,such as electrical and magnetic stimulation,is recommended to enhance functional recovery across different phases of nerve injury.This review concisely outlines the challenges encountered following spinal cord injury,synthesizes existing neurostimulation techniques while emphasizing neuroprotection,repair,and regeneration of impaired connections,and advocates for multi-targeted,task-oriented,and timely interventions.展开更多
A RadioFrequency Quadrupole(RFQ)cooler-buncher system was developed and implemented in a collinear laser spectroscopy setup.This system converts a continuous ion beam into short bunches while enhancing the beam qualit...A RadioFrequency Quadrupole(RFQ)cooler-buncher system was developed and implemented in a collinear laser spectroscopy setup.This system converts a continuous ion beam into short bunches while enhancing the beam quality and reducing the energy spread.The functionality of the RFQ cooler buncher was verified through offline tests with stable rubidium and indium beams delivered from a surface ion source and a laser ablation ion source,respectively.Bunched ion beams with a full width at half maximum of approximately 2μs in the time-of-flight spectrum were successfully achieved with a transmission efficiency exceeding 60%.The implementation of the RFQ cooler-buncher system also significantly improved the overall transmission efficiency of the collinear laser spectroscopy setup.展开更多
In ecological environments,the survival environment of species is often inhomogeneous,and the reproductive process is affected by time delay.System with nonlocal effects and delay can more accurately simulate changes ...In ecological environments,the survival environment of species is often inhomogeneous,and the reproductive process is affected by time delay.System with nonlocal effects and delay can more accurately simulate changes in population density.In this paper,we consider a reaction-diffusion-advection model with nonlocal delay and Dirichlet boundary conditions.First of all,we investigate the well-posedness of solution of model.Then,the existence of positive steady state is proofed by implicit function theorem.Based on a priori estimate for the eigenvalue,we prove the stability of the positive steady state and conclude the associated distribution of Hopf bifurcation.Our research indicates that the combined effects of nonlocal and time delays have a certain impact on the dynamics of the model.展开更多
体例要求1.注释采用脚注、每页排序方式,编号加圈,逐一注明文中引用或参考的资料数据出处。2.中文注释采用宋体小五号,外文注释采用Times New Roman小五号。3.英文注释中的著作和文章名首字母大写,动词、名词、形容词等实词首字母大写,...体例要求1.注释采用脚注、每页排序方式,编号加圈,逐一注明文中引用或参考的资料数据出处。2.中文注释采用宋体小五号,外文注释采用Times New Roman小五号。3.英文注释中的著作和文章名首字母大写,动词、名词、形容词等实词首字母大写,介词、连词、冠词字母小写。4.网络材料应是研究机构、国际组织/机构、行业或专业组织/机构、政府等官方网站的权威材料,并须标注投稿时能够访问的有效网址。展开更多
This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relativ...This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relative motion dynamics model,a prescribed time output feedback control strategy is proposed.A prescribed-time extended state observer is designed to estimate the relative velocity and external disturbances.The disturbance estimates are then used as the feedforward component of the controller.Building on this framework,a novel prescribed-time active disturbance rejection control strategy for position tracking is developed via a backstepping control design.The convergence of the extended state observer and the stability of the closed-loop system are rigorously analyzed using Lyapunov stability theory.Numerical simulations are performed to validate the effectiveness of the proposed controller.展开更多
A series of blue and blue‑green Ir(Ⅲ)complexes has been investigated theoretically to explore their electronic structures,photophysical properties,efficiency roll‑off effect,and thermal activation delayed fluorescenc...A series of blue and blue‑green Ir(Ⅲ)complexes has been investigated theoretically to explore their electronic structures,photophysical properties,efficiency roll‑off effect,and thermal activation delayed fluorescence(TADF)properties.All calculations were performed using density functional theory(DFT)and time‑dependent density functional theory(TDDFT).Calculations for electronic structures,frontier molecular orbital characteristics(which determine the efficiency roll‑off effect of the complexes),and photophysical properties were conducted using the Gaussian 09 software package.The calculation of spin‑orbit coupling matrix elements<T|HSOC|S>,which determine the TADF properties of the complexes,was performed using the ORCA software package.The calculation results show that the auxiliary ligand tetraphenylimidodiphosphinate(tpip),a strong electron‑withdrawing group,can mitigate the efficiency roll‑off effect of the complex.Furthermore,TADF is observed in one of the designed complexes,(F_(3)Phppy)_(2)Ir(tpip),where F_(3)Phppy=2‑[4‑(2,4,6‑trifluorophenyl)phenyl]pyridine.展开更多
Background:Early control of haemorrhage and optimisation of physiology are guiding principles of resuscitation after injury.Improved outcomes have been previously associated with single,timely interventions.The aim of...Background:Early control of haemorrhage and optimisation of physiology are guiding principles of resuscitation after injury.Improved outcomes have been previously associated with single,timely interventions.The aim of this study was to assess the association between multiple timely life-saving interventions(LSIs)and outcomes of traumatic haemorrhagic shock patients.Methods:A retrospective cohort study was undertaken of injured patients with haemorrhagic shock who presented to Alfered Emergency&Trauma Centre between July 01,2010 and July 31,2014.LSIs studied included chest decompression,control of external haemorrhage,pelvic binder application,transfusion of red cells and coagulation products and surgical control of bleeding through angio-embolisation or operative intervention.The primary exposure variable was timely initiation of≥50%of the indicated interventions.The association between the primary exposure variable and outcome of death at hospital discharge was adjusted for potential confounders using multivariable logistic regression analysis.The association between total pre-hospital times and pre-hospital care times(time from ambulance at scene to trauma centre),in-hospital mortality and timely initiation of≥50%of the indicated interventions were assessed.Results:Of the 168 patients,54(32.1%)patients had≥50%of indicated LSI completed within the specified time period.Timely delivery of LSI was independently associated with improved survival to hospital discharge(adjusted odds ratio(OR)for in-hospital death 0.17;95%confidence interval(CI)0.03–0.83;p=0.028).This association was independent of patient age,pre-hospital care time,injury severity score,initial serum lactate levels and coagulopathy.Among patients with pre-hospital time of≥2 h,2(3.6%)received timely LSIs.Pre-hospital care times of≥2 h were associated with delayed LSIs and with in-hospital death(unadjusted OR 4.3;95%CI 1.4–13.0).Conclusions:Timely completion of LSI when indicated was completed in a small proportion of patients and reflects previous research demonstrating delayed processes and errors even in advanced trauma systems.Timely delivery of a high proportion of LSIs was associated with improved outcomes among patients presenting with haemorrhagic shock after injury.Provision of LSIs in the pre-hospital phase of trauma care has the potential to improve outcomes.展开更多
Large language models(LLMs)have demonstrated significant capabilities in semantic understanding and code generation.However,cybersecurity tasks often require prompting the adaptation of open-source models to this doma...Large language models(LLMs)have demonstrated significant capabilities in semantic understanding and code generation.However,cybersecurity tasks often require prompting the adaptation of open-source models to this domain.Despite their effectiveness,large-parameter LLMs incur substantial memory usage and runtime costs during task inference and downstreamfine-tuning for cybersecurity applications.In this study,we fine-tuned six LLMs with parameters under 4 billion using LoRA(Low-Rank Adaptation)on specific cybersecurity instruction datasets,employing evaluation metrics similar to Hackmentor.Results indicate that post-fine-tuning,smaller models achieved victory or parity rates up to 85%against larger models like Qwen-1.5-14B on cybersecurity test datasets,with the best model reaching a 90%win or tie rate compared to SecGPT.Additionally,these smaller models required significantly less computational resources,reducing fine-tuning times by up to 53%and enhancing efficiency in downstream tasks.Further validation showed that withminimal fine-tuning,our models achieved a performance gain of 21.66%to 31.32%in tactical extraction and 30.69%to 40.42%in technical extraction tasks,significantly outperforming ChatGPT.These findings highlight the potential of smaller parameter LLMs for optimizing performance and resource utilization in cybersecurity applications including methods such as technique and tactic extraction.It will facilitate future research on the application of small-parameter large language models in the cybersecurity domain.展开更多
Drought influences carbon fixation by plants.Therefore,elucidating its impact on carbon fluxes in plants at the ecosystem level is crucial for assessing their role in mitigating climate change.Using carbon fluxes and ...Drought influences carbon fixation by plants.Therefore,elucidating its impact on carbon fluxes in plants at the ecosystem level is crucial for assessing their role in mitigating climate change.Using carbon fluxes and environmental factor data from FLUXNET sites,we analyzed the influence of drought on carbon fluxes,their drivers,time-lag effects,and recovery times across various climatic regions and seasons.Results showed drought significantly decreased gross primary production(GPP),ecosystem respiration,and net ecosystem productivity in arid regions but slightly increased carbon sequestration in humid regions.Summer droughts negatively affected vegetation carbon fluxes,partly offset by the positive impact of spring droughts.Nonforest carbon fluxes were more susceptible to drought effects than forest fluxes.Soil water content(SWC)was the main influence on changes in arid regions,whereas vapor pressure deficit(VPD)dominated humid regions.Decreased SWC and increased VPD reduced carbon sequestration in arid regions but increased it in humid regions.Increased VPD reduced GPP,leading to forest carbon loss,whereas decreased SWC reduced GPP,leading to nonforest carbon loss.The lag time of the drought effects on carbon fluxes was longer in humid regions(19.44 d)than in arid regions(14.71 d).Compared to nonforest areas(16.74 d and 57 d for drought lag and recovery time,respectively),forest areas had a longer lag(18.81 d)and recovery time(92 d).The findings revealed discrepancies in the main factors regulating vegetation carbon fluxes during droughts between arid and humid regions and between forest and nonforest ecosystems.These insights provide a new perspective on understanding and simulating carbon-climate feedback.Enhancing ecosystem diversity is a feasible measure to increase drought resistance.展开更多
AIM:To compare the tear film quantity and stability parameters in keratoconus(KCN)and normal eyes using test breakup time(TBUT),noninvasive TBUT(NITBUT),and Schirmer test.METHODS:All participants(n=166),including pati...AIM:To compare the tear film quantity and stability parameters in keratoconus(KCN)and normal eyes using test breakup time(TBUT),noninvasive TBUT(NITBUT),and Schirmer test.METHODS:All participants(n=166),including patients with KCN and age-matched healthy individuals with normal corneas,were recruited from those referred to Farabi Eye Hospital,Iran,in 2023.To better account for genetic and environmental factors,the control group comprised healthy individuals who were relatives of KCN patients and had normal corneal topography.Tear quantity parameters were evaluated in the following order:NITBUT,TBUT,and Schirmer tests.RESULTS:The mean age of cases in KCN(61.7%males)and normal(63.5%males)participants was 27.54±5.44y(range 19 to 38)and 27.52±5.63y(range 20 to 38),respectively(P=0.976).NIBUT,TBUT,and Schirmer’s tests were significantly lower in KCN group compared to normal controls(all P<0.001).The mean difference for NIBUT was-7.81s(P<0.001),and for TBUT was-7.61s(P<0.001).Schirmer test values were also significantly lower in the KCN group,with a mean difference of-5.61 mm compared to normal people(P<0.001).CONCLUSION:Our findings demonstrate significant tear film impairment in KCN.The reductions in NIBUT,TBUT and Schirmer scores highlight an underlying tear film dysfunction in KCN that extends beyond the morphological changes of the cornea.展开更多
Hard disk drives(HDDs)serve as the primary storage devices in modern data centers.Once a failure occurs,it often leads to severe data loss,significantly degrading the reliability of storage systems.Numerous studies ha...Hard disk drives(HDDs)serve as the primary storage devices in modern data centers.Once a failure occurs,it often leads to severe data loss,significantly degrading the reliability of storage systems.Numerous studies have proposed machine learning-based HDD failure prediction models.However,the Self-Monitoring,Analysis,and Reporting Technology(SMART)attributes differ across HDD manufacturers.We define hard drives of the same brand and model as homogeneous HDD groups,and those from different brands or models as heterogeneous HDD groups.In practical engineering scenarios,a data center is often composed of a heterogeneous population of HDDs,spanning multiple vendors and models.Existing research predominantly focuses on homogeneous datasets,ignoring the model’s generalization capability across heterogeneous HDDs.As a result,HDD models with limited samples often suffer from poor training effectiveness and prediction performance.To address this issue,we investigate generalizable SMART predictors across heterogeneous HDD groups.By extracting time-series features within a fixed sliding time window,we propose a Heterogeneous Disk Failure Prediction Method based on Time Series Features(HDFPM)framework.This method is adaptable to HDD models with limited sample sizes,thereby enhancing its applicability and robustness across diverse drive populations.Experimental results show that the proposed model achieves an F1-score of 0.9518 when applied to two different Seagate HDD models,while maintaining the False Positive Rate(FPR)below 1%.After incorporating the Complexity-Ratio Dynamic Time Warping(CDTW)based feature enhancement method,the best prediction model achieves a True Positive Rate(TPR)of up to 0.93 between the two models.For next-day failure prediction across various Seagate models,the model achieves an F1-score of up to 0.8792.Moreover,the experimental results also show that within the same brand,the higher the proportion of shared SMART attributes across different models,the better the prediction performance.In addition,HDFPMdemonstrates the best stability andmost significant performance in heterogeneous environments.展开更多
Overseas investors are enthusiastic about the Chinese stock market as the equities are attractively priced and investors can expect profitable returns in the long「un. This is the verdict of Mark Makepeace, head of FT...Overseas investors are enthusiastic about the Chinese stock market as the equities are attractively priced and investors can expect profitable returns in the long「un. This is the verdict of Mark Makepeace, head of FTSE Russell, the second largest index provider in the world, whose organization will include Chinese shares in its major benchmarks.展开更多
1.(选择性必修一P2)Sometimes the smell alone can do the trick(奏效,起作用,达到目的),not to mention the lovely creamy flavour, which works like a time machine immediately transporting me back to my sunny childhood.
Chilo suppressalis(Walker)is one of the most important rice pests worldwide,posing a significant challenge to effective control.To develop a precision-timed,eco-friendly management strategy,overwintering population in...Chilo suppressalis(Walker)is one of the most important rice pests worldwide,posing a significant challenge to effective control.To develop a precision-timed,eco-friendly management strategy,overwintering population investigation and dynamic monitoring of C.suppressalis populations were conducted in the Meishan region of Sichuan,China,from 2023 to 2024.The optimal timing for insecticide application was estimated,followed by field trials evaluating the efficacy of different insecticides.Results demonstrated that the peak emergence of first-generation adults typically occurred in early July(under the environmental conditions of the Meishan region),with the ambient humidity below 75%and temperature around 29◦C.Pesticide efficacy trials show that insecticide combinations exhibited superior control.Notably,a combined treatment of emamectin benzoate⋅methoxyfenozide+chlorantraniliprole achieved the highest control efficacy(90.05%)and a corresponding yield of 12,491.55 kg/ha.All tested treatments were determined to be safe for rice growth.Furthermore,this optimized strategy resulted in notable economic benefits,including a 50%reduction in pesticide usage and cost savings of 4796.15 CNY compared to conventional practices.This study provides valuable insights into sustainable rice production and pest management and,for the first time,proposes a precision application time window based on intelligent monitoring.展开更多
基金The research is supported by the Natural Science Foundation of China(NSFC)General Research(Grant number 41971386)Hong Kong Research Grant Council(RGC)General Research Fund(Grant number 12301820)+2 种基金The work is a part of PhD research funded by Hong Kong PhD Fellowship Scheme(HKPFS)Natural Science Foundation of China(NSFC)General Program(Grant number 41971386)Hong Kong Research Grant Council(RGC)General Research Fund(Grant number 12301820).
文摘Timely and reliable estimation of regional crop yield is a vital component of food security assessment, especially in developing regions. The traditional crop forecasting methods need ample time and labor to collect and process field data to release official yield reports. Satellite remote sensing data is considered a cost-effective and accurate way of predicting crop yield at pixel-level. In this study, maximum Enhanced Vegetation Index (EVI) during the crop-growing season was integrated with Machine Learning Regression (MLR) models to estimate wheat and rice yields in Pakistan’s Punjab province. Five MLR models were compared using a fivefold cross-validation method for their predictive accuracy. The study results revealed that the regression model based on the Gaussian process outperformed over other models. The best performing model attained coefficient of determination (R^(2)), Root Mean Square Error (RMSE, t/ ha), and Mean Absolute Error (MAE, t/ha) of 0.75, 0.281, and 0.236 for wheat;0.68, 0.112, and 0.091 for rice, respectively. The proposed method made it feasible to predict wheat and rice 6- 8 weeks before the harvest. The early prediction of crop yield and its spatial distribution in the region can help formulate efficient agricultural policies for sustainable social, environmental, and economic progress.
基金supported by the National Natural Science Foundation of China(60774091)
文摘Quorum systems have been used to solve the problem of data consistency in distributed fault-tolerance systems.But when intrusions occur,traditional quorum systems have some disadvantages.For example,synchronous quorum systems are subject to DOS attacks,while asynchronous quorum systems need a larger system size(at least 3f+1 for generic data,and f fewer for self-verifying data).In order to solve the problems above,an intrusion-tolerance quorum system(ITQS)of hybrid time model based on trust timely computing base is presented(TTCB).The TTCB is a trust secure real-time component inside the server with a well defined interface and separated from the operation system.It is in the synchronous communication environment while the application layer in the server deals with read-write requests and executes update-copy protocols asynchronously.The architectural hybridization of synchrony and asynchrony can achieve the data consistency and availability correctly.We also build two kinds of ITQSes based on TTCB,i.e.,the symmetrical and the asymmetrical TTCB quorum systems.In the performance evaluations,we show that TTCB quorum systems are of smaller size,lower load and higher availability.
文摘Background: Ensuring prompt diagnosis and timely malaria treatment will prevent most cases of uncomplicated malaria from progressing to severe and fatal illness. To avoid this progression, treatment must begin as soon as possible, generally within 24 hours after symptoms onset. The reason why mothers/caretakers delay in malaria prompt diagnosis and timely treatment for under-five is not well studied in the study area as well as in Ethiopia. Objective: To assess determinants of delay in malaria prompt diagnosis and timely treatment among under-five children in Shashogo Woreda, Hadiya Zone, Southern Ethiopia, 2013. Methods: An unmatched case control study was conducted from March 25-April 25, 2013. A total sample size of 302 with 151 cases and 151 controls were selected by systematic random sampling techniques. Cases were under-five children who had clinical malaria and sought treatment after 24 hours of symptoms onset, and controls were under-five children who had clinical malaria and sought treatment within 24 hours of symptoms onset. Both bivariate and multivariate logistic regressions were done to identify determinant of delay in malaria prompt diagnosis and timely treatment. Results: A total of 151 mothers/caretakers of cases and 151 mothers/caretakers of controls were interviewed. Illiterate mothers (AOR = 7.14;95%CI: 1.10, 46.39), monthly income ≤500 ETB (AOR = 5.49;95%CI: 2.09, 14.45), females sex (AOR = 3.45;95%CI: 1.62, 7.34), distance from health facility >5 km (AOR = 4.31;95%CI: 1.22, 15.23), absence of history of child death (AOR = 4.21;95%CI: 1.514, 11.68), side effects of antimalarial drugs (AOR = 2.91;95%CI: 1.15, 7.33) and khat chewing (AOR = 2.38;95%CI: 1.28, 5.79) were determinants of delay in malaria prompt diagnosis and timely treatment of under-five children. Conclusion: Mother’s education, monthly income, distance from health facility, absence of history of child death, complained about side effects of drugs and khat chewing were predictors of delay of prompt diagnosis and timely malaria treatment. Effective malaria control programs revision would be required to avoid delay of prompt diagnosis and timely treatment for under-five children.
文摘In recent years,significant breakthroughs have been achieved in the exploration of deep volcanic rocks in the Junggar Basin,highlighting their substantial exploration potential.The complex distribution of volcanic reservoirs is attributed to the multi-phase tectonic evolution within the basin,with their superior reservoir properties playing a crucial role in natural gas formation.However,due to the combined effects of multi-cyclic volcanic eruptions and tectonic activities,predicting volcanic facies distribution and favorable reservoirs remains highly challenging.This study focuses on the third member of the Jiamuhe Formation in the Zhongguai Uplift.By integrating drilling and petrophysical data with well-seismic analysis techniques,a seismic identification model for volcanic reservoirs has been established.The findings reveal that different facies exhibit distinct seismic response characteristics.Andesite,rhyolite,volcanic breccia,and volcanic clastic rocks show variability in amplitude,frequency,and continuity.Using structural-guided filtering,high-resolution coherence analysis,and 3D body carving techniques,the locations of volcanic craters and eruption centers were successfully identified,further clarifying the distribution patterns of volcanic facies.By combining multi-attribute clustering analysis and seismic attribute extraction,a volcanic facies zone distribution map was generated,and favorable exploration directions for volcanic reservoirs were proposed.The study provides technical guidance for the exploration of deep volcanic oil and gas reservoirs in the Junggar Basin and holds significant application value.
文摘Ideally,firms should discontinue projects that become unprofitable.Managers,however,continue to operate such projects because of their limited employment horizons and empire-building motivations(Jensen,1986; Ball,2001).Prior studies suggest that timely loss recognition in accounting earnings enables lenders,shareholders,and boards of directors to identify unprofitable projects; thereby,enabling them to force managers to discontinue such projects before large value erosion occurs.However,this conjecture has not been tested empirically.Consistent with this notion,we find that timely loss recognition increases the likelihood of timely closures of unprofitable projects.Moreover,managers,by announcing late discontinuations of such projects,reveal their inability to select good projects and/or to contain losses,when projects turn unprofitable.Accordingly,thereafter,the fund providers and board of directors are likely to demand improved timeliness of loss recognition and stringent scrutiny of firms' capital expenditure plans.Consistently,we find that firms that announce large discontinuation losses reduce capital expenditures and improve timeliness of loss recognition in subsequent years.Our study provides evidence that timely loss reporting affects "real" economic decisions and creates economic benefits.
基金supported by the National Key Research and Development Program of China,No.2023YFC3603705(to DX)the National Natural Science Foundation of China,No.82302866(to YZ).
文摘After spinal cord injury,impairment of the sensorimotor circuit can lead to dysfunction in the motor,sensory,proprioceptive,and autonomic nervous systems.Functional recovery is often hindered by constraints on the timing of interventions,combined with the limitations of current methods.To address these challenges,various techniques have been developed to aid in the repair and reconstruction of neural circuits at different stages of injury.Notably,neuromodulation has garnered considerable attention for its potential to enhance nerve regeneration,provide neuroprotection,restore neurons,and regulate the neural reorganization of circuits within the cerebral cortex and corticospinal tract.To improve the effectiveness of these interventions,the implementation of multitarget early interventional neuromodulation strategies,such as electrical and magnetic stimulation,is recommended to enhance functional recovery across different phases of nerve injury.This review concisely outlines the challenges encountered following spinal cord injury,synthesizes existing neurostimulation techniques while emphasizing neuroprotection,repair,and regeneration of impaired connections,and advocates for multi-targeted,task-oriented,and timely interventions.
基金supported by the National Natural Science Foundation of China(Nos.12027809,12350007)National Key R&D Program of China(Nos.2022YFA1605100,2023YFA1606403,and 2023YFE0101600)+1 种基金New Cornerstone Science Foundation through the XPLORER PRIZEfunding from the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation program under grant agreement No.679038.
文摘A RadioFrequency Quadrupole(RFQ)cooler-buncher system was developed and implemented in a collinear laser spectroscopy setup.This system converts a continuous ion beam into short bunches while enhancing the beam quality and reducing the energy spread.The functionality of the RFQ cooler buncher was verified through offline tests with stable rubidium and indium beams delivered from a surface ion source and a laser ablation ion source,respectively.Bunched ion beams with a full width at half maximum of approximately 2μs in the time-of-flight spectrum were successfully achieved with a transmission efficiency exceeding 60%.The implementation of the RFQ cooler-buncher system also significantly improved the overall transmission efficiency of the collinear laser spectroscopy setup.
基金Supported by the Natural Science Foundation of Shanghai(23ZR1401700)National Natural Science Foundation of China(12471157)。
文摘In ecological environments,the survival environment of species is often inhomogeneous,and the reproductive process is affected by time delay.System with nonlocal effects and delay can more accurately simulate changes in population density.In this paper,we consider a reaction-diffusion-advection model with nonlocal delay and Dirichlet boundary conditions.First of all,we investigate the well-posedness of solution of model.Then,the existence of positive steady state is proofed by implicit function theorem.Based on a priori estimate for the eigenvalue,we prove the stability of the positive steady state and conclude the associated distribution of Hopf bifurcation.Our research indicates that the combined effects of nonlocal and time delays have a certain impact on the dynamics of the model.
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文摘This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relative motion dynamics model,a prescribed time output feedback control strategy is proposed.A prescribed-time extended state observer is designed to estimate the relative velocity and external disturbances.The disturbance estimates are then used as the feedforward component of the controller.Building on this framework,a novel prescribed-time active disturbance rejection control strategy for position tracking is developed via a backstepping control design.The convergence of the extended state observer and the stability of the closed-loop system are rigorously analyzed using Lyapunov stability theory.Numerical simulations are performed to validate the effectiveness of the proposed controller.
文摘A series of blue and blue‑green Ir(Ⅲ)complexes has been investigated theoretically to explore their electronic structures,photophysical properties,efficiency roll‑off effect,and thermal activation delayed fluorescence(TADF)properties.All calculations were performed using density functional theory(DFT)and time‑dependent density functional theory(TDDFT).Calculations for electronic structures,frontier molecular orbital characteristics(which determine the efficiency roll‑off effect of the complexes),and photophysical properties were conducted using the Gaussian 09 software package.The calculation of spin‑orbit coupling matrix elements<T|HSOC|S>,which determine the TADF properties of the complexes,was performed using the ORCA software package.The calculation results show that the auxiliary ligand tetraphenylimidodiphosphinate(tpip),a strong electron‑withdrawing group,can mitigate the efficiency roll‑off effect of the complex.Furthermore,TADF is observed in one of the designed complexes,(F_(3)Phppy)_(2)Ir(tpip),where F_(3)Phppy=2‑[4‑(2,4,6‑trifluorophenyl)phenyl]pyridine.
文摘Background:Early control of haemorrhage and optimisation of physiology are guiding principles of resuscitation after injury.Improved outcomes have been previously associated with single,timely interventions.The aim of this study was to assess the association between multiple timely life-saving interventions(LSIs)and outcomes of traumatic haemorrhagic shock patients.Methods:A retrospective cohort study was undertaken of injured patients with haemorrhagic shock who presented to Alfered Emergency&Trauma Centre between July 01,2010 and July 31,2014.LSIs studied included chest decompression,control of external haemorrhage,pelvic binder application,transfusion of red cells and coagulation products and surgical control of bleeding through angio-embolisation or operative intervention.The primary exposure variable was timely initiation of≥50%of the indicated interventions.The association between the primary exposure variable and outcome of death at hospital discharge was adjusted for potential confounders using multivariable logistic regression analysis.The association between total pre-hospital times and pre-hospital care times(time from ambulance at scene to trauma centre),in-hospital mortality and timely initiation of≥50%of the indicated interventions were assessed.Results:Of the 168 patients,54(32.1%)patients had≥50%of indicated LSI completed within the specified time period.Timely delivery of LSI was independently associated with improved survival to hospital discharge(adjusted odds ratio(OR)for in-hospital death 0.17;95%confidence interval(CI)0.03–0.83;p=0.028).This association was independent of patient age,pre-hospital care time,injury severity score,initial serum lactate levels and coagulopathy.Among patients with pre-hospital time of≥2 h,2(3.6%)received timely LSIs.Pre-hospital care times of≥2 h were associated with delayed LSIs and with in-hospital death(unadjusted OR 4.3;95%CI 1.4–13.0).Conclusions:Timely completion of LSI when indicated was completed in a small proportion of patients and reflects previous research demonstrating delayed processes and errors even in advanced trauma systems.Timely delivery of a high proportion of LSIs was associated with improved outcomes among patients presenting with haemorrhagic shock after injury.Provision of LSIs in the pre-hospital phase of trauma care has the potential to improve outcomes.
文摘Large language models(LLMs)have demonstrated significant capabilities in semantic understanding and code generation.However,cybersecurity tasks often require prompting the adaptation of open-source models to this domain.Despite their effectiveness,large-parameter LLMs incur substantial memory usage and runtime costs during task inference and downstreamfine-tuning for cybersecurity applications.In this study,we fine-tuned six LLMs with parameters under 4 billion using LoRA(Low-Rank Adaptation)on specific cybersecurity instruction datasets,employing evaluation metrics similar to Hackmentor.Results indicate that post-fine-tuning,smaller models achieved victory or parity rates up to 85%against larger models like Qwen-1.5-14B on cybersecurity test datasets,with the best model reaching a 90%win or tie rate compared to SecGPT.Additionally,these smaller models required significantly less computational resources,reducing fine-tuning times by up to 53%and enhancing efficiency in downstream tasks.Further validation showed that withminimal fine-tuning,our models achieved a performance gain of 21.66%to 31.32%in tactical extraction and 30.69%to 40.42%in technical extraction tasks,significantly outperforming ChatGPT.These findings highlight the potential of smaller parameter LLMs for optimizing performance and resource utilization in cybersecurity applications including methods such as technique and tactic extraction.It will facilitate future research on the application of small-parameter large language models in the cybersecurity domain.
基金supported by the National Natural Science Foundation of China(grant no.32371866)。
文摘Drought influences carbon fixation by plants.Therefore,elucidating its impact on carbon fluxes in plants at the ecosystem level is crucial for assessing their role in mitigating climate change.Using carbon fluxes and environmental factor data from FLUXNET sites,we analyzed the influence of drought on carbon fluxes,their drivers,time-lag effects,and recovery times across various climatic regions and seasons.Results showed drought significantly decreased gross primary production(GPP),ecosystem respiration,and net ecosystem productivity in arid regions but slightly increased carbon sequestration in humid regions.Summer droughts negatively affected vegetation carbon fluxes,partly offset by the positive impact of spring droughts.Nonforest carbon fluxes were more susceptible to drought effects than forest fluxes.Soil water content(SWC)was the main influence on changes in arid regions,whereas vapor pressure deficit(VPD)dominated humid regions.Decreased SWC and increased VPD reduced carbon sequestration in arid regions but increased it in humid regions.Increased VPD reduced GPP,leading to forest carbon loss,whereas decreased SWC reduced GPP,leading to nonforest carbon loss.The lag time of the drought effects on carbon fluxes was longer in humid regions(19.44 d)than in arid regions(14.71 d).Compared to nonforest areas(16.74 d and 57 d for drought lag and recovery time,respectively),forest areas had a longer lag(18.81 d)and recovery time(92 d).The findings revealed discrepancies in the main factors regulating vegetation carbon fluxes during droughts between arid and humid regions and between forest and nonforest ecosystems.These insights provide a new perspective on understanding and simulating carbon-climate feedback.Enhancing ecosystem diversity is a feasible measure to increase drought resistance.
文摘AIM:To compare the tear film quantity and stability parameters in keratoconus(KCN)and normal eyes using test breakup time(TBUT),noninvasive TBUT(NITBUT),and Schirmer test.METHODS:All participants(n=166),including patients with KCN and age-matched healthy individuals with normal corneas,were recruited from those referred to Farabi Eye Hospital,Iran,in 2023.To better account for genetic and environmental factors,the control group comprised healthy individuals who were relatives of KCN patients and had normal corneal topography.Tear quantity parameters were evaluated in the following order:NITBUT,TBUT,and Schirmer tests.RESULTS:The mean age of cases in KCN(61.7%males)and normal(63.5%males)participants was 27.54±5.44y(range 19 to 38)and 27.52±5.63y(range 20 to 38),respectively(P=0.976).NIBUT,TBUT,and Schirmer’s tests were significantly lower in KCN group compared to normal controls(all P<0.001).The mean difference for NIBUT was-7.81s(P<0.001),and for TBUT was-7.61s(P<0.001).Schirmer test values were also significantly lower in the KCN group,with a mean difference of-5.61 mm compared to normal people(P<0.001).CONCLUSION:Our findings demonstrate significant tear film impairment in KCN.The reductions in NIBUT,TBUT and Schirmer scores highlight an underlying tear film dysfunction in KCN that extends beyond the morphological changes of the cornea.
基金supported by the Tianjin Manufacturing High Quality Development Special Foundation(No.20232185)the Roycom Foundation(No.70306901).
文摘Hard disk drives(HDDs)serve as the primary storage devices in modern data centers.Once a failure occurs,it often leads to severe data loss,significantly degrading the reliability of storage systems.Numerous studies have proposed machine learning-based HDD failure prediction models.However,the Self-Monitoring,Analysis,and Reporting Technology(SMART)attributes differ across HDD manufacturers.We define hard drives of the same brand and model as homogeneous HDD groups,and those from different brands or models as heterogeneous HDD groups.In practical engineering scenarios,a data center is often composed of a heterogeneous population of HDDs,spanning multiple vendors and models.Existing research predominantly focuses on homogeneous datasets,ignoring the model’s generalization capability across heterogeneous HDDs.As a result,HDD models with limited samples often suffer from poor training effectiveness and prediction performance.To address this issue,we investigate generalizable SMART predictors across heterogeneous HDD groups.By extracting time-series features within a fixed sliding time window,we propose a Heterogeneous Disk Failure Prediction Method based on Time Series Features(HDFPM)framework.This method is adaptable to HDD models with limited sample sizes,thereby enhancing its applicability and robustness across diverse drive populations.Experimental results show that the proposed model achieves an F1-score of 0.9518 when applied to two different Seagate HDD models,while maintaining the False Positive Rate(FPR)below 1%.After incorporating the Complexity-Ratio Dynamic Time Warping(CDTW)based feature enhancement method,the best prediction model achieves a True Positive Rate(TPR)of up to 0.93 between the two models.For next-day failure prediction across various Seagate models,the model achieves an F1-score of up to 0.8792.Moreover,the experimental results also show that within the same brand,the higher the proportion of shared SMART attributes across different models,the better the prediction performance.In addition,HDFPMdemonstrates the best stability andmost significant performance in heterogeneous environments.
文摘Overseas investors are enthusiastic about the Chinese stock market as the equities are attractively priced and investors can expect profitable returns in the long「un. This is the verdict of Mark Makepeace, head of FTSE Russell, the second largest index provider in the world, whose organization will include Chinese shares in its major benchmarks.
文摘1.(选择性必修一P2)Sometimes the smell alone can do the trick(奏效,起作用,达到目的),not to mention the lovely creamy flavour, which works like a time machine immediately transporting me back to my sunny childhood.
基金funded by the National Key R&D Project‘Innovation and Integration of Key Technologies for Integration of Agricultural Machinery and Agronomy in Weak Links of Hybrid Mid-season Rice in Hilly Areas of Southwest China’(2023YFD2301901).
文摘Chilo suppressalis(Walker)is one of the most important rice pests worldwide,posing a significant challenge to effective control.To develop a precision-timed,eco-friendly management strategy,overwintering population investigation and dynamic monitoring of C.suppressalis populations were conducted in the Meishan region of Sichuan,China,from 2023 to 2024.The optimal timing for insecticide application was estimated,followed by field trials evaluating the efficacy of different insecticides.Results demonstrated that the peak emergence of first-generation adults typically occurred in early July(under the environmental conditions of the Meishan region),with the ambient humidity below 75%and temperature around 29◦C.Pesticide efficacy trials show that insecticide combinations exhibited superior control.Notably,a combined treatment of emamectin benzoate⋅methoxyfenozide+chlorantraniliprole achieved the highest control efficacy(90.05%)and a corresponding yield of 12,491.55 kg/ha.All tested treatments were determined to be safe for rice growth.Furthermore,this optimized strategy resulted in notable economic benefits,including a 50%reduction in pesticide usage and cost savings of 4796.15 CNY compared to conventional practices.This study provides valuable insights into sustainable rice production and pest management and,for the first time,proposes a precision application time window based on intelligent monitoring.
