Objective:This study aimed to examine the reliability and validity of the Chinese version of the Behavioral Inhibition System/Behavioral Activation System(BIS/BAS)scales among stroke survivors.Methods:The cross-sectio...Objective:This study aimed to examine the reliability and validity of the Chinese version of the Behavioral Inhibition System/Behavioral Activation System(BIS/BAS)scales among stroke survivors.Methods:The cross-sectional study was conducted at four comprehensive hospitals in Taizhou,Jiangsu,China.A sample of 232 first-ever stroke survivors were recruited from June to August 2023.Validity was examined using face validity and construct validity,which used confirmatory factor analysis(CFA)and known-group analysis.Reliability was evaluated by internal consistency and test-retest reliability.Results:The BIS/BAS scales demonstrated satisfactory face validity.The findings of CFAs supported the original four-factor structure of BAS-reward,BAS-drive,BAS-fun seeking,and BIS with acceptable model fit indices.Discriminative validity,assessed via known-group analysis,indicated that stroke survivors with probable depression had significantly lower mean BAS-reward,BAS-drive,and BAS-fun seeking scores(P<0.001)and a higher mean BIS score(P=0.028)compared to those without probable depression.The internal consistency,measured by Cronbach’s a coefficients for the subscales,ranged from 0.669 to 0.964.Test-retest reliability,assessed using intra-class correlation coefficients,ranged from 0.61 to 0.93.Conclusions:The Chinese version of the BIS/BAS scales could be a reliable and valid instrument for measuring behavioral activation among stroke survivors.展开更多
Ecosystem services(ES)mapping and models have advanced in recent years.Improvements were made,and the assessments have transitioned from qualitative to quantitative.Although this is an important advancement,the ES map...Ecosystem services(ES)mapping and models have advanced in recent years.Improvements were made,and the assessments have transitioned from qualitative to quantitative.Although this is an important advancement,the ES mapping and modelling validation step has been overlooked,and this raises an important question in the credibility of the outcomes.This has been an important and unsolved issue in the ES research community that needs to be tackled.This highlight paper discusses the importance of validating single ES mapping and models.Conducting this using field or proximal/remote sensing raw data and not data from other models or stakeholder evaluation is important.A validation step should be mandatory in ES frameworks since it can assess the models’veracity,contribute to identifying the model’s weaknesses/strengths and ultimately represent a scientific advance in the field.This is easier to apply to the biophysical mapping and models of regulating and provisioning ES than to cultural ES,as the latter rely more on perception and cultural contexts.Also,ES supply models are easier to validate than demand and flow models.Robust and well-grounded models are essential for ensuring the reliability of individual ES maps and models and should be integrated into decision-making processes.Although several challenges arise related to the costs of data collection,in several cases prohibitive,and the time and the expertise needed to conduct this sampling and analysis,this is likely an imperative step that needs to be considered in the future.This will be beneficial in establishing ES research and improving decision-making and wellbeing.展开更多
Background:Sport climbing is becoming incredibly popular both in the general population and among athletes.No consensus exists regarding evidence-based sport-specific performance evaluation;therefore,this systematic r...Background:Sport climbing is becoming incredibly popular both in the general population and among athletes.No consensus exists regarding evidence-based sport-specific performance evaluation;therefore,this systematic review was aimed at analyzing determinants of sport climbing performance and evaluation methods by comparing climbers of different levels.Methods:PubMed,Scopus,and Web of Science were searched up to December 20,2022.Studies providing the self-reported climbing ability associated with different functional outcomes in groups of climbers of contiguous performance levels were eligible.Results:74 studies were finally included.Various methods have been proposed to evaluate determinants of sport climbing performance.Climbing-specific assessments were able to discriminate climbers of different levels when compared to general functional tests.Test validity resulted high for climbing-specific cardiorespiratory endurance as well as muscular-strength,-endurance,and-power;similarly,reliability was good except for cardiorespiratory endurance.Climbing-specific flexibility assessment resulted in high reliability but moderate validity,whereas balance showed low validity.Considerable conflicting evidence was found regarding anthropometric characteristics.Conclusion:The present analysis identified cardiorespiratory endurance as well as muscular-strength,-endurance,and-power as determinants of sport climbing performance.In contrast,balance,flexibility,and anthropometric characteristics seem to count less.This review also proposes an evidence-based Functional Sport Climbing test battery for asses sing performance determinants,which includes tests that have been identified to be valid,reliable,and feasible.While athletes and coaches should rely on evidence-based and standardized evaluation methods,researchers may design specific large-scale trials as a resource for providing additional,homogenous,and comparable data to improve scientific evidence and professionalism in this popular sport discipline.展开更多
The nature of pramāṅa system,outlined by Dignāga(c.480-540 CE)and further elaborated upon by Dharmakīrti(c.600-660 CE),is an important part of the Buddhist logico-epistemological tradition.Within this pramāṅa syst...The nature of pramāṅa system,outlined by Dignāga(c.480-540 CE)and further elaborated upon by Dharmakīrti(c.600-660 CE),is an important part of the Buddhist logico-epistemological tradition.Within this pramāṅa system,self-awareness(svasaṃvedana)is considered a hallmark of the access to the mental states and factors.However,some of the key research often focuses on interpreting the valid cognition system and self-awareness separately,lacking specific descriptions of their interrelationship.This paper argues that self-awareness is not merely a byproduct of valid cognition but is intimately connected to it.Specifically,I posit that self-awareness should be regarded as the ultimate result of valid cognition within the Pramāṇa system.展开更多
A self-centering bridge bent equipped with energy-dissipation(ED)beams is proposed.Quasi-static tests are conducted on self-centering bridge bents,both with and without ED beams,to validate the accuracy of the corresp...A self-centering bridge bent equipped with energy-dissipation(ED)beams is proposed.Quasi-static tests are conducted on self-centering bridge bents,both with and without ED beams,to validate the accuracy of the corresponding numerical models.The effects of various param-eters,such as the web area of ED beams,prestressing force of tendons,tendon arrangements,and number of column segments,on the seismic performance of self-centering bridge bents with ED beams are evaluated using the validated numerical model.The results demonstrate that the nu-merical models accurately replicate the quasi-static test results,with average errors in the lateral force remaining below 9.6%.The web area of ED beams significantly affects the strength,cumulative energy dissipation,and relative self-centering index(RSI)of the self-centering bridge bents.Increasing the prestressing force enhances the lateral force and self-centering capability of the bridge bents but has minimal effect on their ED capacity.Reducing the num-ber of segments in each column enhances the lateral force and cumulative hysteretic energy dissipation of the self-centering bridge bents while exerting an insignificant effect on the RSI.Thus,the proposed novel system is highly suitable for doubleor multicolumn piers supporting bridges in regions prone to strong earthquakes.展开更多
It is fundamental and useful to investigate how deep learning forecasting models(DLMs)perform compared to operational oceanography forecast systems(OFSs).However,few studies have intercompared their performances using...It is fundamental and useful to investigate how deep learning forecasting models(DLMs)perform compared to operational oceanography forecast systems(OFSs).However,few studies have intercompared their performances using an identical reference.In this study,three physically reasonable DLMs are implemented for the forecasting of the sea surface temperature(SST),sea level anomaly(SLA),and sea surface velocity in the South China Sea.The DLMs are validated against both the testing dataset and the“OceanPredict”Class 4 dataset.Results show that the DLMs'RMSEs against the latter increase by 44%,245%,302%,and 109%for SST,SLA,current speed,and direction,respectively,compared to those against the former.Therefore,different references have significant influences on the validation,and it is necessary to use an identical and independent reference to intercompare the DLMs and OFSs.Against the Class 4 dataset,the DLMs present significantly better performance for SLA than the OFSs,and slightly better performances for other variables.The error patterns of the DLMs and OFSs show a high degree of similarity,which is reasonable from the viewpoint of predictability,facilitating further applications of the DLMs.For extreme events,the DLMs and OFSs both present large but similar forecast errors for SLA and current speed,while the DLMs are likely to give larger errors for SST and current direction.This study provides an evaluation of the forecast skills of commonly used DLMs and provides an example to objectively intercompare different DLMs.展开更多
Pressure-preserved coring technologies are critical for deep-earth resource exploration but are constrained by the inability to achieve multidirectional coring,restricting exploration range while escalating costs and ...Pressure-preserved coring technologies are critical for deep-earth resource exploration but are constrained by the inability to achieve multidirectional coring,restricting exploration range while escalating costs and environmental impacts.We developed a multidirectional pressure-preserved coring system based on magnetic control for deep-earth environments up to 5000 m.The system integrates a magnetically controlled method and key pressure-preserved components to ensure precise self-triggering and self-sealing.It is supported by geometric control equations for optimizing structural stability.Their structure was verified and optimized through theoretical and numerical calculations to meet design objectives.To clarify the self-triggering mechanism in complex environments,a dynamic interference model was established,verifying stability during multidirectional coring.The prototype was fabricated,and functional tests confirmed that it met its design objectives.In a 300-meter-deep test inclined well,10 coring operations were completed with a 100%pressure-preserved success rate,confirming the accuracy of the dynamic interference model analysis.Field trials in a 1970-meter-deep inclined petroleum well,representative of complex environments,demonstrated an in-situ pressure preservation efficiency of 92.18%at 22 MPa.This system innovatively expands the application scope of pressure-preserved coring,providing technical support for efficient and sustainable deep resources exploration and mining.展开更多
BACKGROUND The rising global prevalence of gastroesophageal reflux disease(GERD)has been closely linked to lifestyle changes driven by globalization.GERD imposes a substantial public health burden,affecting quality of...BACKGROUND The rising global prevalence of gastroesophageal reflux disease(GERD)has been closely linked to lifestyle changes driven by globalization.GERD imposes a substantial public health burden,affecting quality of life and leading to potential complications.Early intervention through lifestyle modification can prevent disease onset;however,there is a lack of effective risk prediction models that emphasize primary prevention.AIM To develop and validate a GERD Risk Scoring System(GRSS)aimed at identifying high-risk individuals and promoting primary prevention strategies.METHODS A 45-item questionnaire encompassing major lifestyle and demographic risk factors was developed and validated.It was administered to healthy controls and GERD patients.Two regression models-one using continuous variables and another using categorized variables-were used to develop a computational prediction equation and a clinically applicable scoring scale.An independent validation cohort of 355 participants was used to assess model performance in terms of discrimination(C-index),calibration,sensitivity,specificity,internal consistency(Cronbach's alpha),and test-retest reliability(intraclass correlation coefficient,Bland-Altman analysis).RESULTS Significant associations were observed between GERD and key lifestyle factors.The derived GRSS equation and scoring scale demonstrated strong discriminative ability,with high sensitivity and specificity.The scoring system exhibited excellent internal consistency(Cronbach’s alpha)and strong test-retest reliability.The C-index indicated excellent predictive accuracy in both derivation and validation cohorts.CONCLUSION GRSS offers a novel and validated approach to GERD risk prediction,combining a robust equation for digital applications and a practical scale for clinical use.Its ability to accurately identify at-risk individuals supports a paradigm shift toward primary prevention,underscoring its significance in addressing the growing burden of GERD at the population level.展开更多
Objective To develop and evaluate an automated system for digitizing audiograms,classifying hearing loss levels,and comparing their performance with traditional methods and otolaryngologists'interpretations.Design...Objective To develop and evaluate an automated system for digitizing audiograms,classifying hearing loss levels,and comparing their performance with traditional methods and otolaryngologists'interpretations.Designed and Methods We conducted a retrospective diagnostic study using 1,959 audiogram images from patients aged 7 years and older at the Faculty of Medicine,Vajira Hospital,Navamindradhiraj University.We employed an object detection approach to digitize audiograms and developed multiple machine learning models to classify six hearing loss levels.The dataset was split into 70%training(1,407 images)and 30%testing(352 images)sets.We compared our model's performance with classifications based on manually extracted audiogram values and otolaryngologists'interpretations.Result Our object detection-based model achieved an F1-score of 94.72%in classifying hearing loss levels,comparable to the 96.43%F1-score obtained using manually extracted values.The Light Gradient Boosting Machine(LGBM)model is used as the classifier for the manually extracted data,which achieved top performance with 94.72%accuracy,94.72%f1-score,94.72 recall,and 94.72 precision.In object detection based model,The Random Forest Classifier(RFC)model showed the highest 96.43%accuracy in predicting hearing loss level,with a F1-score of 96.43%,recall of 96.43%,and precision of 96.45%.Conclusion Our proposed automated approach for audiogram digitization and hearing loss classification performs comparably to traditional methods and otolaryngologists'interpretations.This system can potentially assist otolaryngologists in providing more timely and effective treatment by quickly and accurately classifying hearing loss.展开更多
In order to investigate the alternate operation characteristics of a solar-ground source heat pump system（SGSHPS）,various alternate operation modes are put forward and defined.A two-dimensional mathematical model wi...In order to investigate the alternate operation characteristics of a solar-ground source heat pump system（SGSHPS）,various alternate operation modes are put forward and defined.A two-dimensional mathematical model with freezing/melting phase changes is developed for the heat transfer analysis of the soil.Based on the numerical solution of the model,the variation trends of underground soil temperature of the SGSHPS operated in various alternate operation modes are discussed.The results indicate that,for the day-night and short-time interval alternate operation modes without solar energy,the operation time fraction of a solar heat source should be confined to from 50% to 58% when operated in an alternate period of 24 h.Meanwhile,the disadvantages of a natural resumption of soil temperature can be overcome effectively by solar energy filling,and an optimal operation effect can be achieved by integrating the mode of solar energy filling with other alternate modes.In addition,the accuracy of the presented model is verified by the experimental data of borehole wall temperatures.The conclusions can provide a reference for the optimization operation of the SGSHPS.展开更多
In this paper, A fluid vector rudder flying-wing UAV is employed as the design object, so as to study the nonlinear design method and flight validation. For the maneuvering flight control, this paper presents a contro...In this paper, A fluid vector rudder flying-wing UAV is employed as the design object, so as to study the nonlinear design method and flight validation. For the maneuvering flight control, this paper presents a control structure. This control structure included the inner loop linearization decoupling methods to eliminate the known negative coupling and the outer loop backstepping methods for trajectory tracking control. The stability of the control structure has been proved in this paper. Compared with the traditional backstepping control method, this controller increases the inner loop decoupling structure and retains the aerodynamic damping term which makes the linearized system a weak nonlinear system.This structure can not only reduce the conservatism of the outer loop controller design, but also is convenient for engineering implementation. Simulation and flight validation results show that the proposed control scheme is effective.展开更多
Following the progress of satellite data assimilation in the 1990s, the combination of meteorological satellites and numerical models has changed the way scientists understand the earth. With the evolution of numerica...Following the progress of satellite data assimilation in the 1990s, the combination of meteorological satellites and numerical models has changed the way scientists understand the earth. With the evolution of numerical weather prediction models and earth system models, meteorological satellites will play a more important role in earth sciences in the future. As part of the space-based infrastructure, the Fengyun (FY) meteorological satellites have contributed to earth science sustainability studies through an open data policy and stable data quality since the first launch of the FY-1A satellite in 1988. The capability of earth system monitoring was greatly enhanced after the second-generation polar orbiting FY-3 satellites and geostationary orbiting FY-4 satellites were developed. Meanwhile, the quality of the products generated from the FY-3 and FY-4 satellites is comparable to the well-known MODIS products. FY satellite data has been utilized broadly in weather forecasting, climate and climate change investigations, environmental disaster monitoring, etc. This article reviews the instruments mounted on the FY satellites. Sensor-dependent level 1 products (radiance data) and inversion algorithm-dependent level 2 products (geophysical parameters) are introduced. As an example, some typical geophysical parameters, such as wildfires, lightning, vegetation indices, aerosol products, soil moisture, and precipitation estimation have been demonstrated and validated by in-situ observations and other well-known satellite products. To help users access the FY products, a set of data sharing systems has been developed and operated. The newly developed data sharing system based on cloud technology has been illustrated to improve the efficiency of data delivery.展开更多
The Chinese Aeronautical Establishment（CAE） Aerodynamic Validation Model（AVM）is a dual-purpose test geometry dedicated to verify the aerodynamic performance of a conceptual intercontinental jet aircraft and to pro...The Chinese Aeronautical Establishment（CAE） Aerodynamic Validation Model（AVM）is a dual-purpose test geometry dedicated to verify the aerodynamic performance of a conceptual intercontinental jet aircraft and to provide a dataset for CFD software validation. To this end, a scaled model of the AVM was tested in the High-Speed Tunnel（HST） of the German-Dutch Wind-tunnels（DNW） with special test consideration and instrumentation. For complementary analysis of experimental results, specific CAE-AVM geometries are analyzed using a CAE inhouse CFD code. The specific geometries consist of a baseline aircraft, an aircraft with a deformed wing shape, and an aircraft with both a deformed wing shape and a representation of the model support system used in the wind tunnel. Detailed analysis of numerical and experimental results is presented; both the combined and individual attributions of wing deformation and support system interference on wing pressure distributions and longitudinal aerodynamic characteristics are summarized.展开更多
BACKGROUND Artificial intelligence in colonoscopy is an emerging field,and its application may help colonoscopists improve inspection quality and reduce the rate of missed polyps and adenomas.Several deep learning-bas...BACKGROUND Artificial intelligence in colonoscopy is an emerging field,and its application may help colonoscopists improve inspection quality and reduce the rate of missed polyps and adenomas.Several deep learning-based computer-assisted detection(CADe)techniques were established from small single-center datasets,and unrepresentative learning materials might confine their application and generalization in wide practice.Although CADes have been reported to identify polyps in colonoscopic images and videos in real time,their diagnostic performance deserves to be further validated in clinical practice.AIM To train and test a CADe based on multicenter high-quality images of polyps and preliminarily validate it in clinical colonoscopies.METHODS With high-quality screening and labeling from 55 qualified colonoscopists,a dataset consisting of over 71000 images from 20 centers was used to train and test a deep learning-based CADe.In addition,the real-time diagnostic performance of CADe was tested frame by frame in 47 unaltered full-ranged videos that contained 86 histologically confirmed polyps.Finally,we conducted a selfcontrolled observational study to validate the diagnostic performance of CADe in real-world colonoscopy with the main outcome measure of polyps per colonoscopy in Changhai Hospital.RESULTS The CADe was able to identify polyps in the test dataset with 95.0%sensitivity and 99.1%specificity.For colonoscopy videos,all 86 polyps were detected with 92.2%sensitivity and 93.6%specificity in frame-by-frame analysis.In the prospective validation,the sensitivity of CAD in identifying polyps was 98.4%(185/188).Folds,reflections of light and fecal fluid were the main causes of false positives in both the test dataset and clinical colonoscopies.Colonoscopists can detect more polyps(0.90 vs 0.82,P<0.001)and adenomas(0.32 vs 0.30,P=0.045)with the aid of CADe,particularly polyps<5 mm and flat polyps(0.65 vs 0.57,P<0.001;0.74 vs 0.67,P=0.001,respectively).However,high efficacy is not realized in colonoscopies with inadequate bowel preparation and withdrawal time(P=0.32;P=0.16,respectively).CONCLUSION CADe is feasible in the clinical setting and might help endoscopists detect more polyps and adenomas,and further confirmation is warranted.展开更多
Objective:This study aimed to develop and validate a risk scoring system to identify high-risk individuals carrying malignant lesions in stomach for tailored gastric cancer screening.Methods:A gastric cancer risk scor...Objective:This study aimed to develop and validate a risk scoring system to identify high-risk individuals carrying malignant lesions in stomach for tailored gastric cancer screening.Methods:A gastric cancer risk scoring system(GC-RSS)was developed based on questionnaire-based predictors for gastric cancer derived from systematic literature review.To assess the capability of this system for discrimination,risk scores for 8,214 and 7,235 outpatient subjects accepting endoscopic examination in two endoscopy centers,and 32,630 participants in a community-based cohort in China were calculated to plot receiver operating characteristic curves and generate area under the curve(AUC).To evaluate the performance of GC-RSS,the screening proportion,sensitivity and detection rate ratio compared to universal screening were used under different risk score cutoff values.Results:GC-RSS comprised nine predictors including advanced age,male gender,low body mass index(<18.5 kg/m^(2)),family history of gastric cancer,cigarette smoking,consumption of alcohol,preference for salty food,irregularity of meals and consumption of preserved food.This tool performed well in determining the risk of malignant gastric lesions with AUCs of 0.763,0.706 and 0.696 in three validation sets.When subjects with risk scores≥5 were evaluated with endoscopy,nearly 50%of these endoscopies could be saved with a detection rate of over 1.5 times achieved.When the cutoff was set at 8,only about 10%of subjects with the highest risk would be offered endoscopy,and detection rates for gastric cancer could be increased 2-4 fold compared to universal screening.Conclusions:An effective questionnaire-based GC-RSS was developed and validated.This tool may play an important role in establishing a tailored screening strategy for gastric cancer in China.展开更多
Remote sensing tools are becoming increasingly important for providing spatial information on water use by different ecosystems. Despite significant advances in remote sensing based evapotranspiration(ET) models in re...Remote sensing tools are becoming increasingly important for providing spatial information on water use by different ecosystems. Despite significant advances in remote sensing based evapotranspiration(ET) models in recent years, important information gaps still exist on the accuracy of the models particularly in arid and semi-arid environments. In this study, we evaluated the Penman-Monteith based MOD16 and the modified Priestley-Taylor(PT-JPL) models at the daily time step against three measured ET datasets. We used data from two summer and one winter rainfall sites in South Africa. One site was dominated by native broad leaf and the other by fine leafed deciduous savanna tree species and C4 grasses. The third site was in the winter rainfall Cape region and had shrubby fynbos vegetation. Actual ET was measured using open-path eddy covariance systems at the summer rainfall sites while a surface energy balance system utilizing the large aperture boundary layer scintillometer was used in the Cape. Model performance varied between sites and between years with the worst estimates(R2<0.50 and RMSE>0.80 mm/d) observed during years with prolonged mid-summer dry spells in the summer rainfall areas. Sensitivity tests on MOD16 showed that the leaf area index, surface conductance and radiation budget parameters had the largest effect on simulated ET. MOD16 ET predictions were improved by:(1) reformulating the emissivity expressions in the net radiation equation;(2) incorporating representative surface conductance values;and(3) including a soil moisture stress function in the transpiration sub-model. Implementing these changes increased the accuracy of MOD16 daily ET predictions at all sites. However, similar adjustments to the PT-JPL model yielded minimal improvements. We conclude that the MOD16 ET model has the potential to accurately predict water use in arid environments provided soil water stress and accurate biome-specific parameters are incorporated.展开更多
This paper reviews the data quality and impact of observations from the FY-3 satellite series used operationally in the ECMWF system. This includes data from the passive microwave radiometers MWHS-1, MWHS-2 and MWRI, ...This paper reviews the data quality and impact of observations from the FY-3 satellite series used operationally in the ECMWF system. This includes data from the passive microwave radiometers MWHS-1, MWHS-2 and MWRI, as well as observations from the radio occultation receiver GNOS. Evaluations against background equivalents show that the quality of the observations is broadly comparable to that of similar instruments on other polar-orbiting satellites, even though biases for the passive microwave observations can be somewhat larger and more complex for some channels. An observing system experiment shows that the FY-3 instruments jointly contribute significantly to the forecast skill in the ECMWF system. Positive impact of up to 2% is seen for most variables out to the day-2 forecasts over hemispheric scales, with significant benefits for total column water vapor or for temperature and wind in the stratosphere out to day 4.展开更多
Hydrogen can serve as a carrier to store renewable energy in large scale.However,hydrogen storage still remains a challenge in the current stage.It is difficult to meet the technical requirements applying the conventi...Hydrogen can serve as a carrier to store renewable energy in large scale.However,hydrogen storage still remains a challenge in the current stage.It is difficult to meet the technical requirements applying the conventional storage of compressed gaseous hydrogen in high-pressure tanks or the solid-state storage of hydrogen in suitable materials.In the present work,a gaseous and solid-state(G-S)hybrid hydrogen storage system with a low working pressure below 5 MPa for a 10 kW hydrogen energy storage experiment platform is developed and validated.A Ti-Mn type hydrogen storage alloy with an effective hydrogen capacity of 1.7 wt%was prepared for the G-S hybrid hydrogen storage system.The G-S hybrid hydrogen storage tank has a high volumetric hydrogen storage density of 40.07 kg H_(2)m^(-3) and stores hydrogen under pressure below5 MPa.It can readily release enough hydrogen at a temperature as low as-15C when the FC system is not fully activated and hot water is not available.The energy storage efficiency of this G-S hybrid hydrogen storage system is calculated to be 86.4%-95.9%when it is combined with an FC system.This work provides a method on how to design a G-S hydrogen storage system based on practical demands and demonstrates that the G-S hybrid hydrogen storage is a promising method for stationary hydrogen storage application.展开更多
Although a number of methods are available for evaluating Linezolid and its possible impurities, a common method for separation if its potential impurities, degradants and enantiomer in a single method with good effic...Although a number of methods are available for evaluating Linezolid and its possible impurities, a common method for separation if its potential impurities, degradants and enantiomer in a single method with good efficiency remain unavailable. With the objective of developing an advanced method with shorter runtimes, a simple, precise, accurate stability-indicating LC method was developed for the determination of purity of Linezolid drug substance and drug products in bulk samples and pharmaceutical dosage forms in the presence of its impurities and degradation products. This method is capable of separating all the related substances of Linezolid along with the chiral impurity. This method can also be used for the estimation of assay of Linezolid in drug substance as well as in drug product. The method was developed using Chiralpak IA (250 mm 4.6 mm, 5 mm) column. A mixture of acetonitrile, ethanol, n-butyl amine and trifluoro acetic acid in 96:4:0.10:0.16 (v/v/v/v) ratio was used as a mobile phase. The eluted compounds were monitored at 254 nm. Linezolid was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from main peak and its impurities, proving the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, limit of detection, limit of quantification, precision, linearity, accuracy, robustness and system suitability.展开更多
In order to provide relay communication supports for future Chinese lunar exploration program,Queqiao-2 relay communication satellite was developed.Queqiao-2 can perform scientific observations with three kinds of sci...In order to provide relay communication supports for future Chinese lunar exploration program,Queqiao-2 relay communication satellite was developed.Queqiao-2 can perform scientific observations with three kinds of scientific instruments on board.The system design of Queqiao-2,including mission orbit and transfer orbit design,configuration and layout design,housekeeping and information flow design,power supply and distribution design,GNC and propulsion system design,communication links design,etc.,was accomplished through comprehensive tradeoff and evaluation on technical maturity,availability,schedule,cost,and so on.With a view to reducing development risk,both the platform and relay communication payloads were developed based on significant heritage from previous Queqiao relay satellite and other relevant spacecraft.Queqiao-2 features flexible system architecture to support multiple frequencies,modulations,data rates and software reconfigurations to meet new user requirements.Subsequent to a successful launch on March 20,2024,by means of 5 orbit maneuvers,Queqiao-2 was inserted into a highly elliptical frozen mission orbit around the moon with a 24h period on schedule.Following on-orbit tests and calibrations,Queqiao-2 has possessed the capacity to provide reliable relay communication services to multiple lunar exploration missions,as well as the capacity to perform scientific observations.Under the support of Queqiao-2,Chang′e-6 achieved its ambitious mission goal to collect and return samples from the moon′s mysterious far side.In the meanwhile,Queqiao-2 has also paved the way for the following Chinese lunar exploration missions including Chang′e-7 and Chang′e-8.The design life time of Queqiao-2 is more than 8 years.Benefit from flexibility and extensibility of relay communication system design,it is convenient to provide relay communication services for future lunar exploration missions of both China and other countries.In addition,innovative scientific observations would be performed during the period that no relay communication task is arranged.The system design of Queqiao-2 reflects the development philosophy of technical innovations and inheritance integration.Based on highly flexible and extensible system architecture,multiple and concurrent relay communication mission requirements can be met.It can provide strong supports for future lunar exploration missions.Successful launching,orbit entering and on-orbit tests of Queqiao-2 verified the correct design principle and versatility.By means of Queqiao-2,more innovative scientific outcomes are anticipated and lunar exploration activities can be facilitated.展开更多
文摘Objective:This study aimed to examine the reliability and validity of the Chinese version of the Behavioral Inhibition System/Behavioral Activation System(BIS/BAS)scales among stroke survivors.Methods:The cross-sectional study was conducted at four comprehensive hospitals in Taizhou,Jiangsu,China.A sample of 232 first-ever stroke survivors were recruited from June to August 2023.Validity was examined using face validity and construct validity,which used confirmatory factor analysis(CFA)and known-group analysis.Reliability was evaluated by internal consistency and test-retest reliability.Results:The BIS/BAS scales demonstrated satisfactory face validity.The findings of CFAs supported the original four-factor structure of BAS-reward,BAS-drive,BAS-fun seeking,and BIS with acceptable model fit indices.Discriminative validity,assessed via known-group analysis,indicated that stroke survivors with probable depression had significantly lower mean BAS-reward,BAS-drive,and BAS-fun seeking scores(P<0.001)and a higher mean BIS score(P=0.028)compared to those without probable depression.The internal consistency,measured by Cronbach’s a coefficients for the subscales,ranged from 0.669 to 0.964.Test-retest reliability,assessed using intra-class correlation coefficients,ranged from 0.61 to 0.93.Conclusions:The Chinese version of the BIS/BAS scales could be a reliable and valid instrument for measuring behavioral activation among stroke survivors.
基金supported by the project Monetary valuation of soil ecosystem services and creation of initiatives to invest in soil health:setting a framework for the inclusion of soil health in business and in the policy making process(InBestSoil)(Horizon Europe)Grant agreement ID:101091099。
文摘Ecosystem services(ES)mapping and models have advanced in recent years.Improvements were made,and the assessments have transitioned from qualitative to quantitative.Although this is an important advancement,the ES mapping and modelling validation step has been overlooked,and this raises an important question in the credibility of the outcomes.This has been an important and unsolved issue in the ES research community that needs to be tackled.This highlight paper discusses the importance of validating single ES mapping and models.Conducting this using field or proximal/remote sensing raw data and not data from other models or stakeholder evaluation is important.A validation step should be mandatory in ES frameworks since it can assess the models’veracity,contribute to identifying the model’s weaknesses/strengths and ultimately represent a scientific advance in the field.This is easier to apply to the biophysical mapping and models of regulating and provisioning ES than to cultural ES,as the latter rely more on perception and cultural contexts.Also,ES supply models are easier to validate than demand and flow models.Robust and well-grounded models are essential for ensuring the reliability of individual ES maps and models and should be integrated into decision-making processes.Although several challenges arise related to the costs of data collection,in several cases prohibitive,and the time and the expertise needed to conduct this sampling and analysis,this is likely an imperative step that needs to be considered in the future.This will be beneficial in establishing ES research and improving decision-making and wellbeing.
文摘Background:Sport climbing is becoming incredibly popular both in the general population and among athletes.No consensus exists regarding evidence-based sport-specific performance evaluation;therefore,this systematic review was aimed at analyzing determinants of sport climbing performance and evaluation methods by comparing climbers of different levels.Methods:PubMed,Scopus,and Web of Science were searched up to December 20,2022.Studies providing the self-reported climbing ability associated with different functional outcomes in groups of climbers of contiguous performance levels were eligible.Results:74 studies were finally included.Various methods have been proposed to evaluate determinants of sport climbing performance.Climbing-specific assessments were able to discriminate climbers of different levels when compared to general functional tests.Test validity resulted high for climbing-specific cardiorespiratory endurance as well as muscular-strength,-endurance,and-power;similarly,reliability was good except for cardiorespiratory endurance.Climbing-specific flexibility assessment resulted in high reliability but moderate validity,whereas balance showed low validity.Considerable conflicting evidence was found regarding anthropometric characteristics.Conclusion:The present analysis identified cardiorespiratory endurance as well as muscular-strength,-endurance,and-power as determinants of sport climbing performance.In contrast,balance,flexibility,and anthropometric characteristics seem to count less.This review also proposes an evidence-based Functional Sport Climbing test battery for asses sing performance determinants,which includes tests that have been identified to be valid,reliable,and feasible.While athletes and coaches should rely on evidence-based and standardized evaluation methods,researchers may design specific large-scale trials as a resource for providing additional,homogenous,and comparable data to improve scientific evidence and professionalism in this popular sport discipline.
文摘The nature of pramāṅa system,outlined by Dignāga(c.480-540 CE)and further elaborated upon by Dharmakīrti(c.600-660 CE),is an important part of the Buddhist logico-epistemological tradition.Within this pramāṅa system,self-awareness(svasaṃvedana)is considered a hallmark of the access to the mental states and factors.However,some of the key research often focuses on interpreting the valid cognition system and self-awareness separately,lacking specific descriptions of their interrelationship.This paper argues that self-awareness is not merely a byproduct of valid cognition but is intimately connected to it.Specifically,I posit that self-awareness should be regarded as the ultimate result of valid cognition within the Pramāṇa system.
基金The National Natural Science Foundation of China(No.52278189)Zhejiang Provincial Natural Science Foundation of China(No.LY24E080002).
文摘A self-centering bridge bent equipped with energy-dissipation(ED)beams is proposed.Quasi-static tests are conducted on self-centering bridge bents,both with and without ED beams,to validate the accuracy of the corresponding numerical models.The effects of various param-eters,such as the web area of ED beams,prestressing force of tendons,tendon arrangements,and number of column segments,on the seismic performance of self-centering bridge bents with ED beams are evaluated using the validated numerical model.The results demonstrate that the nu-merical models accurately replicate the quasi-static test results,with average errors in the lateral force remaining below 9.6%.The web area of ED beams significantly affects the strength,cumulative energy dissipation,and relative self-centering index(RSI)of the self-centering bridge bents.Increasing the prestressing force enhances the lateral force and self-centering capability of the bridge bents but has minimal effect on their ED capacity.Reducing the num-ber of segments in each column enhances the lateral force and cumulative hysteretic energy dissipation of the self-centering bridge bents while exerting an insignificant effect on the RSI.Thus,the proposed novel system is highly suitable for doubleor multicolumn piers supporting bridges in regions prone to strong earthquakes.
基金supported by the National Natural Science Foundation of China(Grant Nos.42375062 and 42275158)the National Key Scientific and Technological Infrastructure project“Earth System Science Numerical Simulator Facility”(EarthLab)the Natural Science Foundation of Gansu Province(Grant No.22JR5RF1080)。
文摘It is fundamental and useful to investigate how deep learning forecasting models(DLMs)perform compared to operational oceanography forecast systems(OFSs).However,few studies have intercompared their performances using an identical reference.In this study,three physically reasonable DLMs are implemented for the forecasting of the sea surface temperature(SST),sea level anomaly(SLA),and sea surface velocity in the South China Sea.The DLMs are validated against both the testing dataset and the“OceanPredict”Class 4 dataset.Results show that the DLMs'RMSEs against the latter increase by 44%,245%,302%,and 109%for SST,SLA,current speed,and direction,respectively,compared to those against the former.Therefore,different references have significant influences on the validation,and it is necessary to use an identical and independent reference to intercompare the DLMs and OFSs.Against the Class 4 dataset,the DLMs present significantly better performance for SLA than the OFSs,and slightly better performances for other variables.The error patterns of the DLMs and OFSs show a high degree of similarity,which is reasonable from the viewpoint of predictability,facilitating further applications of the DLMs.For extreme events,the DLMs and OFSs both present large but similar forecast errors for SLA and current speed,while the DLMs are likely to give larger errors for SST and current direction.This study provides an evaluation of the forecast skills of commonly used DLMs and provides an example to objectively intercompare different DLMs.
基金supported by the National Key Research and Development Program of China(No.2023YFF0615401)Joint Funds of the National Natural Science Foundation of China(No.U24A2087)+1 种基金Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences(No.SKLGME022009)the National Natural Science Foundation of China(No.42477191)。
文摘Pressure-preserved coring technologies are critical for deep-earth resource exploration but are constrained by the inability to achieve multidirectional coring,restricting exploration range while escalating costs and environmental impacts.We developed a multidirectional pressure-preserved coring system based on magnetic control for deep-earth environments up to 5000 m.The system integrates a magnetically controlled method and key pressure-preserved components to ensure precise self-triggering and self-sealing.It is supported by geometric control equations for optimizing structural stability.Their structure was verified and optimized through theoretical and numerical calculations to meet design objectives.To clarify the self-triggering mechanism in complex environments,a dynamic interference model was established,verifying stability during multidirectional coring.The prototype was fabricated,and functional tests confirmed that it met its design objectives.In a 300-meter-deep test inclined well,10 coring operations were completed with a 100%pressure-preserved success rate,confirming the accuracy of the dynamic interference model analysis.Field trials in a 1970-meter-deep inclined petroleum well,representative of complex environments,demonstrated an in-situ pressure preservation efficiency of 92.18%at 22 MPa.This system innovatively expands the application scope of pressure-preserved coring,providing technical support for efficient and sustainable deep resources exploration and mining.
文摘BACKGROUND The rising global prevalence of gastroesophageal reflux disease(GERD)has been closely linked to lifestyle changes driven by globalization.GERD imposes a substantial public health burden,affecting quality of life and leading to potential complications.Early intervention through lifestyle modification can prevent disease onset;however,there is a lack of effective risk prediction models that emphasize primary prevention.AIM To develop and validate a GERD Risk Scoring System(GRSS)aimed at identifying high-risk individuals and promoting primary prevention strategies.METHODS A 45-item questionnaire encompassing major lifestyle and demographic risk factors was developed and validated.It was administered to healthy controls and GERD patients.Two regression models-one using continuous variables and another using categorized variables-were used to develop a computational prediction equation and a clinically applicable scoring scale.An independent validation cohort of 355 participants was used to assess model performance in terms of discrimination(C-index),calibration,sensitivity,specificity,internal consistency(Cronbach's alpha),and test-retest reliability(intraclass correlation coefficient,Bland-Altman analysis).RESULTS Significant associations were observed between GERD and key lifestyle factors.The derived GRSS equation and scoring scale demonstrated strong discriminative ability,with high sensitivity and specificity.The scoring system exhibited excellent internal consistency(Cronbach’s alpha)and strong test-retest reliability.The C-index indicated excellent predictive accuracy in both derivation and validation cohorts.CONCLUSION GRSS offers a novel and validated approach to GERD risk prediction,combining a robust equation for digital applications and a practical scale for clinical use.Its ability to accurately identify at-risk individuals supports a paradigm shift toward primary prevention,underscoring its significance in addressing the growing burden of GERD at the population level.
文摘Objective To develop and evaluate an automated system for digitizing audiograms,classifying hearing loss levels,and comparing their performance with traditional methods and otolaryngologists'interpretations.Designed and Methods We conducted a retrospective diagnostic study using 1,959 audiogram images from patients aged 7 years and older at the Faculty of Medicine,Vajira Hospital,Navamindradhiraj University.We employed an object detection approach to digitize audiograms and developed multiple machine learning models to classify six hearing loss levels.The dataset was split into 70%training(1,407 images)and 30%testing(352 images)sets.We compared our model's performance with classifications based on manually extracted audiogram values and otolaryngologists'interpretations.Result Our object detection-based model achieved an F1-score of 94.72%in classifying hearing loss levels,comparable to the 96.43%F1-score obtained using manually extracted values.The Light Gradient Boosting Machine(LGBM)model is used as the classifier for the manually extracted data,which achieved top performance with 94.72%accuracy,94.72%f1-score,94.72 recall,and 94.72 precision.In object detection based model,The Random Forest Classifier(RFC)model showed the highest 96.43%accuracy in predicting hearing loss level,with a F1-score of 96.43%,recall of 96.43%,and precision of 96.45%.Conclusion Our proposed automated approach for audiogram digitization and hearing loss classification performs comparably to traditional methods and otolaryngologists'interpretations.This system can potentially assist otolaryngologists in providing more timely and effective treatment by quickly and accurately classifying hearing loss.
基金The National Key Technology R&D Program of Chinaduring the 11th Five-Year Plan Period(No.2008BAJ12B04)China Postdoctoral Science Foundation(No.20090461050)+1 种基金the Project of Researchand Development of Ministry of Housing and Urban-Rural Development ofChina(No.2008-K1-26)the New Century Talent Project of Yangzhou University for Excellent Young Backbone Teacher(2008)
文摘In order to investigate the alternate operation characteristics of a solar-ground source heat pump system（SGSHPS）,various alternate operation modes are put forward and defined.A two-dimensional mathematical model with freezing/melting phase changes is developed for the heat transfer analysis of the soil.Based on the numerical solution of the model,the variation trends of underground soil temperature of the SGSHPS operated in various alternate operation modes are discussed.The results indicate that,for the day-night and short-time interval alternate operation modes without solar energy,the operation time fraction of a solar heat source should be confined to from 50% to 58% when operated in an alternate period of 24 h.Meanwhile,the disadvantages of a natural resumption of soil temperature can be overcome effectively by solar energy filling,and an optimal operation effect can be achieved by integrating the mode of solar energy filling with other alternate modes.In addition,the accuracy of the presented model is verified by the experimental data of borehole wall temperatures.The conclusions can provide a reference for the optimization operation of the SGSHPS.
文摘In this paper, A fluid vector rudder flying-wing UAV is employed as the design object, so as to study the nonlinear design method and flight validation. For the maneuvering flight control, this paper presents a control structure. This control structure included the inner loop linearization decoupling methods to eliminate the known negative coupling and the outer loop backstepping methods for trajectory tracking control. The stability of the control structure has been proved in this paper. Compared with the traditional backstepping control method, this controller increases the inner loop decoupling structure and retains the aerodynamic damping term which makes the linearized system a weak nonlinear system.This structure can not only reduce the conservatism of the outer loop controller design, but also is convenient for engineering implementation. Simulation and flight validation results show that the proposed control scheme is effective.
基金This work was supported by the National Key Research and Development Program of China(2018YFB0504900,2018YFB0504905).
文摘Following the progress of satellite data assimilation in the 1990s, the combination of meteorological satellites and numerical models has changed the way scientists understand the earth. With the evolution of numerical weather prediction models and earth system models, meteorological satellites will play a more important role in earth sciences in the future. As part of the space-based infrastructure, the Fengyun (FY) meteorological satellites have contributed to earth science sustainability studies through an open data policy and stable data quality since the first launch of the FY-1A satellite in 1988. The capability of earth system monitoring was greatly enhanced after the second-generation polar orbiting FY-3 satellites and geostationary orbiting FY-4 satellites were developed. Meanwhile, the quality of the products generated from the FY-3 and FY-4 satellites is comparable to the well-known MODIS products. FY satellite data has been utilized broadly in weather forecasting, climate and climate change investigations, environmental disaster monitoring, etc. This article reviews the instruments mounted on the FY satellites. Sensor-dependent level 1 products (radiance data) and inversion algorithm-dependent level 2 products (geophysical parameters) are introduced. As an example, some typical geophysical parameters, such as wildfires, lightning, vegetation indices, aerosol products, soil moisture, and precipitation estimation have been demonstrated and validated by in-situ observations and other well-known satellite products. To help users access the FY products, a set of data sharing systems has been developed and operated. The newly developed data sharing system based on cloud technology has been illustrated to improve the efficiency of data delivery.
文摘The Chinese Aeronautical Establishment（CAE） Aerodynamic Validation Model（AVM）is a dual-purpose test geometry dedicated to verify the aerodynamic performance of a conceptual intercontinental jet aircraft and to provide a dataset for CFD software validation. To this end, a scaled model of the AVM was tested in the High-Speed Tunnel（HST） of the German-Dutch Wind-tunnels（DNW） with special test consideration and instrumentation. For complementary analysis of experimental results, specific CAE-AVM geometries are analyzed using a CAE inhouse CFD code. The specific geometries consist of a baseline aircraft, an aircraft with a deformed wing shape, and an aircraft with both a deformed wing shape and a representation of the model support system used in the wind tunnel. Detailed analysis of numerical and experimental results is presented; both the combined and individual attributions of wing deformation and support system interference on wing pressure distributions and longitudinal aerodynamic characteristics are summarized.
基金the National Key R&D Program of China,No.2018YFC1313103the National Natural Science Foundation of China,No.81670473 and No.81873546+1 种基金the“Shu Guang”Project of Shanghai Municipal Education Commission and Shanghai Education Development Foundation,No.19SG30the Key Area Research and Development Program of Guangdong Province,China,No.2018B010111001.
文摘BACKGROUND Artificial intelligence in colonoscopy is an emerging field,and its application may help colonoscopists improve inspection quality and reduce the rate of missed polyps and adenomas.Several deep learning-based computer-assisted detection(CADe)techniques were established from small single-center datasets,and unrepresentative learning materials might confine their application and generalization in wide practice.Although CADes have been reported to identify polyps in colonoscopic images and videos in real time,their diagnostic performance deserves to be further validated in clinical practice.AIM To train and test a CADe based on multicenter high-quality images of polyps and preliminarily validate it in clinical colonoscopies.METHODS With high-quality screening and labeling from 55 qualified colonoscopists,a dataset consisting of over 71000 images from 20 centers was used to train and test a deep learning-based CADe.In addition,the real-time diagnostic performance of CADe was tested frame by frame in 47 unaltered full-ranged videos that contained 86 histologically confirmed polyps.Finally,we conducted a selfcontrolled observational study to validate the diagnostic performance of CADe in real-world colonoscopy with the main outcome measure of polyps per colonoscopy in Changhai Hospital.RESULTS The CADe was able to identify polyps in the test dataset with 95.0%sensitivity and 99.1%specificity.For colonoscopy videos,all 86 polyps were detected with 92.2%sensitivity and 93.6%specificity in frame-by-frame analysis.In the prospective validation,the sensitivity of CAD in identifying polyps was 98.4%(185/188).Folds,reflections of light and fecal fluid were the main causes of false positives in both the test dataset and clinical colonoscopies.Colonoscopists can detect more polyps(0.90 vs 0.82,P<0.001)and adenomas(0.32 vs 0.30,P=0.045)with the aid of CADe,particularly polyps<5 mm and flat polyps(0.65 vs 0.57,P<0.001;0.74 vs 0.67,P=0.001,respectively).However,high efficacy is not realized in colonoscopies with inadequate bowel preparation and withdrawal time(P=0.32;P=0.16,respectively).CONCLUSION CADe is feasible in the clinical setting and might help endoscopists detect more polyps and adenomas,and further confirmation is warranted.
基金supported by the National Science&Technology Fundamental Resources Investigation Program of China(No.2019FY101102)the National Natural Science Foundation of China(No.82073626,81773501)+5 种基金the National Key R&D Program of China(No.2016YFC0901404)the Beijing-Tianjin-Hebei Basic Research Cooperation Project(No.J200016)the Digestive Medical Coordinated Development Center of Beijing Hospitals Authority(No.XXZ0204)the Beijing Hospitals Authority Youth Programme(No.QML20201101)Sanming Project of Shenzhen(No.SZSM201612061)the Beijing Nova Program(No.Z201100006820093)。
文摘Objective:This study aimed to develop and validate a risk scoring system to identify high-risk individuals carrying malignant lesions in stomach for tailored gastric cancer screening.Methods:A gastric cancer risk scoring system(GC-RSS)was developed based on questionnaire-based predictors for gastric cancer derived from systematic literature review.To assess the capability of this system for discrimination,risk scores for 8,214 and 7,235 outpatient subjects accepting endoscopic examination in two endoscopy centers,and 32,630 participants in a community-based cohort in China were calculated to plot receiver operating characteristic curves and generate area under the curve(AUC).To evaluate the performance of GC-RSS,the screening proportion,sensitivity and detection rate ratio compared to universal screening were used under different risk score cutoff values.Results:GC-RSS comprised nine predictors including advanced age,male gender,low body mass index(<18.5 kg/m^(2)),family history of gastric cancer,cigarette smoking,consumption of alcohol,preference for salty food,irregularity of meals and consumption of preserved food.This tool performed well in determining the risk of malignant gastric lesions with AUCs of 0.763,0.706 and 0.696 in three validation sets.When subjects with risk scores≥5 were evaluated with endoscopy,nearly 50%of these endoscopies could be saved with a detection rate of over 1.5 times achieved.When the cutoff was set at 8,only about 10%of subjects with the highest risk would be offered endoscopy,and detection rates for gastric cancer could be increased 2-4 fold compared to universal screening.Conclusions:An effective questionnaire-based GC-RSS was developed and validated.This tool may play an important role in establishing a tailored screening strategy for gastric cancer in China.
基金supported by the South African Parliamentary Grant to the Council for Scientific and Industrial Research Project (ECHS014, EEEO024, ECHS058 and ECHS052)
文摘Remote sensing tools are becoming increasingly important for providing spatial information on water use by different ecosystems. Despite significant advances in remote sensing based evapotranspiration(ET) models in recent years, important information gaps still exist on the accuracy of the models particularly in arid and semi-arid environments. In this study, we evaluated the Penman-Monteith based MOD16 and the modified Priestley-Taylor(PT-JPL) models at the daily time step against three measured ET datasets. We used data from two summer and one winter rainfall sites in South Africa. One site was dominated by native broad leaf and the other by fine leafed deciduous savanna tree species and C4 grasses. The third site was in the winter rainfall Cape region and had shrubby fynbos vegetation. Actual ET was measured using open-path eddy covariance systems at the summer rainfall sites while a surface energy balance system utilizing the large aperture boundary layer scintillometer was used in the Cape. Model performance varied between sites and between years with the worst estimates(R2<0.50 and RMSE>0.80 mm/d) observed during years with prolonged mid-summer dry spells in the summer rainfall areas. Sensitivity tests on MOD16 showed that the leaf area index, surface conductance and radiation budget parameters had the largest effect on simulated ET. MOD16 ET predictions were improved by:(1) reformulating the emissivity expressions in the net radiation equation;(2) incorporating representative surface conductance values;and(3) including a soil moisture stress function in the transpiration sub-model. Implementing these changes increased the accuracy of MOD16 daily ET predictions at all sites. However, similar adjustments to the PT-JPL model yielded minimal improvements. We conclude that the MOD16 ET model has the potential to accurately predict water use in arid environments provided soil water stress and accurate biome-specific parameters are incorporated.
基金We acknowledge funding from the EUMETSAT Fellowship Programme for Heather LAWRENCE,Katrin LONITZ and David DUNCAN.
文摘This paper reviews the data quality and impact of observations from the FY-3 satellite series used operationally in the ECMWF system. This includes data from the passive microwave radiometers MWHS-1, MWHS-2 and MWRI, as well as observations from the radio occultation receiver GNOS. Evaluations against background equivalents show that the quality of the observations is broadly comparable to that of similar instruments on other polar-orbiting satellites, even though biases for the passive microwave observations can be somewhat larger and more complex for some channels. An observing system experiment shows that the FY-3 instruments jointly contribute significantly to the forecast skill in the ECMWF system. Positive impact of up to 2% is seen for most variables out to the day-2 forecasts over hemispheric scales, with significant benefits for total column water vapor or for temperature and wind in the stratosphere out to day 4.
基金supported by State Grid Corporation of China(No.SGRIDGKJ[2016]123)Education Department of Guangxi Zhuang Autonomous Region(No.2019KY0021)the Natural Science Foundation of Guangxi Province(2019GXNSFBA185004,2018GXNSFAA281308,2019GXNSFAA245050)。
文摘Hydrogen can serve as a carrier to store renewable energy in large scale.However,hydrogen storage still remains a challenge in the current stage.It is difficult to meet the technical requirements applying the conventional storage of compressed gaseous hydrogen in high-pressure tanks or the solid-state storage of hydrogen in suitable materials.In the present work,a gaseous and solid-state(G-S)hybrid hydrogen storage system with a low working pressure below 5 MPa for a 10 kW hydrogen energy storage experiment platform is developed and validated.A Ti-Mn type hydrogen storage alloy with an effective hydrogen capacity of 1.7 wt%was prepared for the G-S hybrid hydrogen storage system.The G-S hybrid hydrogen storage tank has a high volumetric hydrogen storage density of 40.07 kg H_(2)m^(-3) and stores hydrogen under pressure below5 MPa.It can readily release enough hydrogen at a temperature as low as-15C when the FC system is not fully activated and hot water is not available.The energy storage efficiency of this G-S hybrid hydrogen storage system is calculated to be 86.4%-95.9%when it is combined with an FC system.This work provides a method on how to design a G-S hydrogen storage system based on practical demands and demonstrates that the G-S hybrid hydrogen storage is a promising method for stationary hydrogen storage application.
文摘Although a number of methods are available for evaluating Linezolid and its possible impurities, a common method for separation if its potential impurities, degradants and enantiomer in a single method with good efficiency remain unavailable. With the objective of developing an advanced method with shorter runtimes, a simple, precise, accurate stability-indicating LC method was developed for the determination of purity of Linezolid drug substance and drug products in bulk samples and pharmaceutical dosage forms in the presence of its impurities and degradation products. This method is capable of separating all the related substances of Linezolid along with the chiral impurity. This method can also be used for the estimation of assay of Linezolid in drug substance as well as in drug product. The method was developed using Chiralpak IA (250 mm 4.6 mm, 5 mm) column. A mixture of acetonitrile, ethanol, n-butyl amine and trifluoro acetic acid in 96:4:0.10:0.16 (v/v/v/v) ratio was used as a mobile phase. The eluted compounds were monitored at 254 nm. Linezolid was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from main peak and its impurities, proving the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, limit of detection, limit of quantification, precision, linearity, accuracy, robustness and system suitability.
文摘In order to provide relay communication supports for future Chinese lunar exploration program,Queqiao-2 relay communication satellite was developed.Queqiao-2 can perform scientific observations with three kinds of scientific instruments on board.The system design of Queqiao-2,including mission orbit and transfer orbit design,configuration and layout design,housekeeping and information flow design,power supply and distribution design,GNC and propulsion system design,communication links design,etc.,was accomplished through comprehensive tradeoff and evaluation on technical maturity,availability,schedule,cost,and so on.With a view to reducing development risk,both the platform and relay communication payloads were developed based on significant heritage from previous Queqiao relay satellite and other relevant spacecraft.Queqiao-2 features flexible system architecture to support multiple frequencies,modulations,data rates and software reconfigurations to meet new user requirements.Subsequent to a successful launch on March 20,2024,by means of 5 orbit maneuvers,Queqiao-2 was inserted into a highly elliptical frozen mission orbit around the moon with a 24h period on schedule.Following on-orbit tests and calibrations,Queqiao-2 has possessed the capacity to provide reliable relay communication services to multiple lunar exploration missions,as well as the capacity to perform scientific observations.Under the support of Queqiao-2,Chang′e-6 achieved its ambitious mission goal to collect and return samples from the moon′s mysterious far side.In the meanwhile,Queqiao-2 has also paved the way for the following Chinese lunar exploration missions including Chang′e-7 and Chang′e-8.The design life time of Queqiao-2 is more than 8 years.Benefit from flexibility and extensibility of relay communication system design,it is convenient to provide relay communication services for future lunar exploration missions of both China and other countries.In addition,innovative scientific observations would be performed during the period that no relay communication task is arranged.The system design of Queqiao-2 reflects the development philosophy of technical innovations and inheritance integration.Based on highly flexible and extensible system architecture,multiple and concurrent relay communication mission requirements can be met.It can provide strong supports for future lunar exploration missions.Successful launching,orbit entering and on-orbit tests of Queqiao-2 verified the correct design principle and versatility.By means of Queqiao-2,more innovative scientific outcomes are anticipated and lunar exploration activities can be facilitated.
