Spodoptera frugiperda (J.E.Smmith) is one of the major migratory pests warned by the Food and Agriculture Organization (FAO).It has been successfully invaded sugarcane and corn in Jinggu,Longchuan,Gengma,Menghai,Yingj...Spodoptera frugiperda (J.E.Smmith) is one of the major migratory pests warned by the Food and Agriculture Organization (FAO).It has been successfully invaded sugarcane and corn in Jinggu,Longchuan,Gengma,Menghai,Yingjiang,Lancang of Yunan Province,China.In view of the great variety of hosts,wide range of habitats and strong migration ability,S.frugiperda has the potential of causing catastrophic threats to sugarcane production.In this paper,we made a systematic introduction to the morphological and biological characteristics of S.frugiperda,analyzed its occurrence situations and occurrence trends in Yunnan of China and other countries around the world,and proposed the control strategies and measures of ecological regulation and control,natural enemies protection and utilization,biological control,pesticide control and adults trapping based on the outbreak characteristics of S.frugiperda and the actual sugarcane production in low latitude plateau areas.展开更多
Some principles and methods for the dynamic monitoring of forage-livestock bal-ance in the grazing system on the temperate grassland of China were discussed in thispaper. To prepare a dynamic monitoring system or the ...Some principles and methods for the dynamic monitoring of forage-livestock bal-ance in the grazing system on the temperate grassland of China were discussed in thispaper. To prepare a dynamic monitoring system or the forage livestock balance of grazingrangeland system, the following theoretical bases will be observed in this work.展开更多
With the emergence of global environmental change issues,Land Use/Cover Change(LUCC)issues have received increasing attention.Therefore,the dynamic monitoring of LUCC has also become very important.In this paper,preli...With the emergence of global environmental change issues,Land Use/Cover Change(LUCC)issues have received increasing attention.Therefore,the dynamic monitoring of LUCC has also become very important.In this paper,preliminary exploration was made to the research progress on the dynamic monitoring technologies for LUCC as well as their advantages and disadvantages,and prediction was made to the development trend of future monitoring technology.展开更多
The aim of this study was to evaluate the effects of low-dose tibolone therapy on ovarian area, uterine volume and endometrial thickness, and define the cut-off value of endometrial thickness for curettage during uter...The aim of this study was to evaluate the effects of low-dose tibolone therapy on ovarian area, uterine volume and endometrial thickness, and define the cut-off value of endometrial thickness for curettage during uterine bleeding. We followed 619 postmenopausal women, aged 40-60 years, for two years. There were 301 subjects in the low-dose tibolone treatment group and 318 subjects in the control group. The ovarian area, uterine volume and endometrial thickness in all participants were measured by transvaginal ultrasound prior to, one and two years post enrollment, respectively. Endometrial specimens were collected from all subjects with abnormal uterine bleeding during the follow-up period. We found that the uterine volume in the treatment group was greater than that in the control group, and the difference was significant (P〈0.05), but there were no significant differences in ovarian area and endometrial thickness between the two groups (P〉0.05). When the cut-off value for endometrial thickness was 7.35 ram, the sensitivity and specificity were 100% and 79.07%, respectively, and 85.71% and 93.02% when 7.55 mm was set as the cut-offduring tibolone therapy. The results indicate that low-dose tibolone therapy may postpone uterine atrophy and the cut-off value of endometrial thickness may be appropriately adjusted for curettage.展开更多
The environmental change in the wetlands in the southern Mongolian Plateau has important impacts on the environment of North China and even the entire Northeast Asia,from which the global climate change can be underst...The environmental change in the wetlands in the southern Mongolian Plateau has important impacts on the environment of North China and even the entire Northeast Asia,from which the global climate change can be understood on a large scale,especially the climate change in the Mongolian Plateau.This study extracted the information on the wetlands from three stages of remote sensing images(also referred to as RS images)of the study area,including Enhanced Thematic Mapper Plus(ETM+)images of 2000,TM images of 2010,and Landsat 8 Operational Land Imager(OLI)images of 2018.As indicated by the extraction results,the area of wetlands decreased from 796.90 km^(2) of 2000 to 666.24 km^(2) of 2018 at a rate of 7.26 km^(2)/a.The reduced area is 130.66 km^(2),which is about 16.4%reduction.And the patch number of wetlands decreased from 731 of 2000 to 316 of 2018 in the study area,approximately 56.8%reduction(415 patches),and the decrease in the area of the wetlands mainly occurred in the northwest endorheic region.In terms of wetland types,the change of the wetlands was dominated by the decrease of lacustrine wetlands,of which the area and patch number decreased by 106.2 km^(2) and 242,respectively.Furthermore,the area of the lacustrine wetlands decreased at the highest rate of 8.70 km^(2)/a in 2010‒2018.From the perspective of spatial distribution,the wetlands in the western part shrunk more notably than those in the eastern part as a whole in the study area.According to local meteorological data,the precipitation gently decreased and the temperature increased(about 1.7℃)from 1975-2018.Overall,the decrease in the area of the wetlands and the temperature rises in the study area were mainly driven by the Mongolian monsoon climate,reduction in precipitation,and human activities.展开更多
Horqin Sand Land is regarded as the t ypical region for studying the probl em of desertification.The integra-tion of 3S(GIS,GPS and RS)techniques offer a most helpful meth od to study and monitor the dynamics o f dese...Horqin Sand Land is regarded as the t ypical region for studying the probl em of desertification.The integra-tion of 3S(GIS,GPS and RS)techniques offer a most helpful meth od to study and monitor the dynamics o f desertification.Based on the data derived from3perio ds’ multitemporal Landsat TMimagery of the 1990s,the regional land use a nd dynam-ics of desertification in Horqin San d Land were studied.The main results revealed that:1)as long as the general change tendency was concerned,the deserti fication of Horqin Sand Land would co ntinue to spread;2)there was a gradual de-crease in the area of both moving sand dunes and semi-stabilized ones,whi ch meant that fruitful progress had b een made to control the desertification during the 1990s;3)as a result of unreasonable cultivation,the total area of stabilized san d dunes and grassland in the middle and western region decreased obviously.It suggested that the increasing damage caused by human was leading to the hazard of further desertification.So i n the future,it is necessary to take more effec-tive measures to control the spread o f desertification and restore the degraded ecosystems for the purpose of optimizing the global eco-environment in Horqin Sand Land.展开更多
BACKGROUND Some patients with the novel 2019 coronavirus disease(COVID-19)display elevated liver enzymes.Some antiviral drugs that can be used against COVID-19 are associated with a risk of hepatotoxicity.AIM To analy...BACKGROUND Some patients with the novel 2019 coronavirus disease(COVID-19)display elevated liver enzymes.Some antiviral drugs that can be used against COVID-19 are associated with a risk of hepatotoxicity.AIM To analyze the clinical significance of the dynamic monitoring of the liver function of patients with COVID-19.METHODS This was a retrospective study of patients diagnosed with COVID-19 in January and February 2020 at the Department of Infection,Shantou Central Hospital.The exclusion criteria for all patients were:(1)History of chronic liver disease;(2)History of kidney disease;(3)History of coronary heart disease;(4)History of malignancy;or(5)History of diabetes.The serum levels of alanine aminotransferase(ALT),aspartate aminotransferase(AST),γ-glutamyltransferase,and total bilirubin of patients with COVID-19 were measured on days 1,3,7 and 14 after admission,and compared to non-COVID-19 patents.RESULTS Twelve patients with COVID-19(seven men and five women)and twelve controls(eight men and four women)were included.There were one,two,and nine patients with severe,mild,and moderate COVID-19,respectively.There were no differences in age and sex between the two groups(both P>0.05).No significant differences were found in albumin,ALT,AST,γ-glutamyltransferase,or total bilirubin between the controls and the patients with COVID-19 on day 1 of hospitalization(all P>0.05).Serum albumin showed a decreasing trend from days 0 to 7 of hospitalization,reaching the lowest level on day 7.Total bilirubin was higher on day 3 than on day 7.ALT,AST,andγ-glutamyltransferase did not change significantly over time.The severe patient was observed to have ALT levels of 67 U/L and AST levels of 75 U/L on day 7,ALT of 71 U/L and AST of 35 U/L on day 14,and ALT of 210 U/L and AST of 123 U/L on day 21.CONCLUSION Changes in serum liver function indicators are not obvious in the early stage of COVID-19,but clinically significant changes might be observed in severe COVID-19.展开更多
The real-time dynamic deformation monitoring of offshore platforms under environmental excitation is crucial to their safe operation.Although Global Navigation Satellite System-Precise Point Positioning(GNSS-PPP)has b...The real-time dynamic deformation monitoring of offshore platforms under environmental excitation is crucial to their safe operation.Although Global Navigation Satellite System-Precise Point Positioning(GNSS-PPP)has been considered for this purpose,its monitoring accuracy is relatively low.Moreover,the influence of background noise on the dynamic monitoring accuracy of GNSS-PPP remains unclear.Hence,it is imperative to further validate the feasibility of GNSS-PPP for deformation monitoring of offshore platforms.To address these concerns,vibration table tests with different amplitudes and frequencies are conducted.The results demonstrate that GNSS-PPP can effectively monitor horizontal vibration displacement as low as±30 mm,which is consistent with GNSS-RTK.Furthermore,the spectral characteristic of background noise in GNSS-PPP is similar to that of GNSS-RTK(Real Time Kinematic).Building on this observation,an improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise(CEEMDAN)has been proposed to de-noise the data and enhance the dynamic monitoring accuracy of GNSS-PPP.Field monitoring application research is also undertaken,successfully extracting and analyzing the dynamic deformation of an offshore platform structure under environmental excitation using GNSS-PPP monitoring in conjunction with improved CEEMDAN de-noising.By comparing the de-noised dynamic deformation trajectories of the offshore platform during different periods,it is observed that the platform exhibits reversible alternating vibration responses under environmental excitation,with more pronounced displacement deformation in the direction of load action.The research results confirm the feasibility and potential of GNSS-PPP for dynamic deformation monitoring of offshore platforms.展开更多
Dynamic monitoring is an important basic work in the sustainable exploitation and utilization of geothermal resources.It offers basic data for geothermal management department to make out the plan of geothermal resour...Dynamic monitoring is an important basic work in the sustainable exploitation and utilization of geothermal resources.It offers basic data for geothermal management department to make out the plan of geothermal resources by collecting and analyzing the outdoor dynamic monitoring data. Tianjin is one of the earliest cities in exploiting and utilizing geothermal resources,and the展开更多
In order to study the spatial-temporal change and environmental management of regional karst LUCC (land use and land cover change) and its causative environmental effect-rocky desertification by integrating qualitativ...In order to study the spatial-temporal change and environmental management of regional karst LUCC (land use and land cover change) and its causative environmental effect-rocky desertification by integrating qualitative analysis and quantitative analysis, and relying on RS, GIS and GPS (3S) techniques, karst land rocky derification dynamic monitoring and visualization management information system (KLRD.DMVM.IS) is framed, which includes design aim and structure model, function design, database design and model system design. The model system design gives priority to dynamic monitoring, drive force diagnosis, comprehensive evaluation and decision support of karst rocky desertification. From the viewpoint of model type, mathematic expression and its meaning, the dynamic monitoring models are concretely devised to reflect the spatial and temporal changing features and the trend of karst LUCC and rocky desertification. Taking Du'an Yao Autonomic County of Guangxi as an example, the KLRD.DMVM.IS is systematically analyzed in the application of the process and trend of karst LUCC and rocky desertification in Du'an County, and it provides the technical support for the study on karst land rocky desertification.展开更多
The level of deformation development of surrounding rocks is a vital predictor to evaluate impending coal mine disasters and it is important to establish accurate measurements of the deformed status to ensure coal min...The level of deformation development of surrounding rocks is a vital predictor to evaluate impending coal mine disasters and it is important to establish accurate measurements of the deformed status to ensure coal mine safety. Traditional deformation monitoring methods are mostly based on single parameter, in this paper, multiple approaches are integrated: firstly, both electric and elastic models are established,from which electric field distribution and seismic wave recording are calculated and finally, the resistivity profiles and source position information are determined using inversion methods, from which then the deformation and failure of mine floor are evaluated. According to the inversion results of both electric and seismic field signals, multiple-parameter dynamic monitoring of surrounding rock deformation in deep mine can be performed. The methodology is validated using numerical simulation results which shows that the multi-parameter dynamic monitoring methods have better results for surrounding rock deformation in deep mine monitoring than single parameter methods.展开更多
To develop the dynamic monitoring algorithm of visual safety distance in highway, by using the highway video traffic monitoring system, the research platform of four kinds of terrain environment in plateau, mountainou...To develop the dynamic monitoring algorithm of visual safety distance in highway, by using the highway video traffic monitoring system, the research platform of four kinds of terrain environment in plateau, mountainous area, plain and coastal area is established. Results show that through the contrast between the sample data and visibility train of thought, based on the theory of mathematical morphology, expressway visibility dynamic monitoring image information system can be established. Based on the theory of the measurement of the basic formula of visibility, the dynamic model of the optimization is established, set up 200 meters distance visual observation target system, research visual range detection algorithm process.展开更多
Based on the nonlinear error equation of deformation network monitoring, the mathematical model of nonlinear dynamic optimal design of class two was put forward for the deformation network monitoring, in which the tar...Based on the nonlinear error equation of deformation network monitoring, the mathematical model of nonlinear dynamic optimal design of class two was put forward for the deformation network monitoring, in which the target function is the accuracy criterion and the constraint conditions are the network’s sensitivity, reliability and observing cost. Meanwhile a new non derivative solution to the nonlinear dynamic optimal design of class two was also put forward. The solving model uses the difference to stand for the first derivative of functions and solves the revised feasible direction to get the optimal solution to unknown parameters. It can not only make the solution to converge on the minimum point of the constraint problem, but decrease the calculating load.展开更多
For the sake of timely appraising the working con di tion of the bridge, measuring the dynamic characteristics of the bridge structur e is very important and necessary. A GPS dynamic monitoring test was carried out in...For the sake of timely appraising the working con di tion of the bridge, measuring the dynamic characteristics of the bridge structur e is very important and necessary. A GPS dynamic monitoring test was carried out in the Wuhan Baishazhou Bridge, which is one of the longest span cable-stayed bridges having been built in China. This paper introduces the experimental imple menting scheme and data processing method. The vibration characteristics of the middle span of cable-stayed bridge are availably obtained by use of the spectra l analytic approach. The measuring results are very identical to the theoretical designed values. The research demonstrates that, with GPS receiver of the high sampling rate and suitable data processing method, the vibration characteristics of the bridge structure can be determined with high accuracy.展开更多
Remote sensing technique has played an important role in land use dynamic monitoring, but as for the land use dynamic monitoring at county level, traditional remote sensing methods such as satellite imagery visual int...Remote sensing technique has played an important role in land use dynamic monitoring, but as for the land use dynamic monitoring at county level, traditional remote sensing methods such as satellite imagery visual interpretation and computer classification can not meet its demand for accuracy. The result of 1:10 000 land use investigation map has high accuracy, but this method can not be used to dynamically monitor the land use because of its big expenses, long period and difficulty in updating data. In this paper, the characteristics of physiognomy, climate and the status of land use in Dehui County are taken into consideration and a set of method, which takes use of 3S techniques and applies to Northeast China Plain, is come up with. When the land use type of a land parcel changed as a whole, the date updating can be make by changing its land type ID in the attribute table in a GIS. When the land use type of an irregular area changed, GPS receivers are used to position its border. This set of method is characteristic of high accuracy and low expenses. It gets the information of land use change timely and can be used to dynamically monitor the land use. .展开更多
The underground hydropower projects in Southwest China is characterized by large excavation sizes,high geostresses,complicated geological conditions and multiple construction processes.Various disasters such as collap...The underground hydropower projects in Southwest China is characterized by large excavation sizes,high geostresses,complicated geological conditions and multiple construction processes.Various disasters such as collapses,large deformations,rockbursts are frequently encountered,resulting in serious casualties and huge economic losses.This review mainly presents some representative results on microseismic(MS)monitoring and forecasting for disasters in hydropower underground engineering.First,a set of new denoising,spectral analysis,and location methods were developed for better identification and location of MS signals.Then,the tempo-spatial characteristics of MS events were analyzed to understand the relationship between field construction and damages of surrounding rocks.Combined with field construction,geological data,numerical simulation and parametric analysis of MS sources,the focal mechanism of MS events was revealed.A damage constitutive model considering MS fracturing size was put forward and feedback analysis considering the MS damage of underground surrounding rocks was conducted.Next,an MS multi-parameter based risk assessment and early warning method for dynamic disasters were proposed.The technology for control of the damage and deformation of underground surrounding rocks was proposed for underground caverns.Finally,two typical underground powerhouses were selected as case studies.These achievements can provide significant references for prevention and control of dynamic disasters for underground engineering with similar complicated geological conditions.展开更多
Structural Health Monitoring(SHM)systems have become a crucial tool for the operational management of long tunnels.For immersed tunnels exposed to both traffic loads and the effects of the marine environment,efficient...Structural Health Monitoring(SHM)systems have become a crucial tool for the operational management of long tunnels.For immersed tunnels exposed to both traffic loads and the effects of the marine environment,efficiently identifying abnormal conditions from the extensive unannotated SHM data presents a significant challenge.This study proposed amodel-based approach for anomaly detection and conducted validation and comparative analysis of two distinct temporal predictive models using SHM data from a real immersed tunnel.Firstly,a dynamic predictive model-based anomaly detectionmethod is proposed,which utilizes a rolling time window for modeling to achieve dynamic prediction.Leveraging the assumption of temporal data similarity,an interval prediction value deviation was employed to determine the abnormality of the data.Subsequently,dynamic predictive models were constructed based on the Autoregressive Integrated Moving Average(ARIMA)and Long Short-Term Memory(LSTM)models.The hyperparameters of these models were optimized and selected using monitoring data from the immersed tunnel,yielding viable static and dynamic predictive models.Finally,the models were applied within the same segment of SHM data,to validate the effectiveness of the anomaly detection approach based on dynamic predictive modeling.A detailed comparative analysis discusses the discrepancies in temporal anomaly detection between the ARIMA-and LSTM-based models.The results demonstrated that the dynamic predictive modelbased anomaly detection approach was effective for dealing with unannotated SHM data.In a comparison between ARIMA and LSTM,it was found that ARIMA demonstrated higher modeling efficiency,rendering it suitable for short-term predictions.In contrast,the LSTM model exhibited greater capacity to capture long-term performance trends and enhanced early warning capabilities,thereby resulting in superior overall performance.展开更多
The positioning combined with multi-functioning and interactive mechanics in dynamic testing of slender bridges are treated in present paper. The approach takes into account multiple functions in dynamic testing of sl...The positioning combined with multi-functioning and interactive mechanics in dynamic testing of slender bridges are treated in present paper. The approach takes into account multiple functions in dynamic testing of slender bridges constructed of thin-walled structural members with their hierarchical configuration. Theoretical, numerical and experimental in situ assessments of the problem are presented. Some results of the application in situ are submitted.展开更多
基金Supported by the Sugar Crop Research System(CARS-170303)the Training Project of Yunling Industry and Technology Leading Talents(2018LJRC56)the Special Fund of Agricultural Industry Research System in Yunnan Province
文摘Spodoptera frugiperda (J.E.Smmith) is one of the major migratory pests warned by the Food and Agriculture Organization (FAO).It has been successfully invaded sugarcane and corn in Jinggu,Longchuan,Gengma,Menghai,Yingjiang,Lancang of Yunan Province,China.In view of the great variety of hosts,wide range of habitats and strong migration ability,S.frugiperda has the potential of causing catastrophic threats to sugarcane production.In this paper,we made a systematic introduction to the morphological and biological characteristics of S.frugiperda,analyzed its occurrence situations and occurrence trends in Yunnan of China and other countries around the world,and proposed the control strategies and measures of ecological regulation and control,natural enemies protection and utilization,biological control,pesticide control and adults trapping based on the outbreak characteristics of S.frugiperda and the actual sugarcane production in low latitude plateau areas.
文摘Some principles and methods for the dynamic monitoring of forage-livestock bal-ance in the grazing system on the temperate grassland of China were discussed in thispaper. To prepare a dynamic monitoring system or the forage livestock balance of grazingrangeland system, the following theoretical bases will be observed in this work.
文摘With the emergence of global environmental change issues,Land Use/Cover Change(LUCC)issues have received increasing attention.Therefore,the dynamic monitoring of LUCC has also become very important.In this paper,preliminary exploration was made to the research progress on the dynamic monitoring technologies for LUCC as well as their advantages and disadvantages,and prediction was made to the development trend of future monitoring technology.
基金supported by the Sci-tech Research Development Program of Shaanxi Province (No.2015SF015)
文摘The aim of this study was to evaluate the effects of low-dose tibolone therapy on ovarian area, uterine volume and endometrial thickness, and define the cut-off value of endometrial thickness for curettage during uterine bleeding. We followed 619 postmenopausal women, aged 40-60 years, for two years. There were 301 subjects in the low-dose tibolone treatment group and 318 subjects in the control group. The ovarian area, uterine volume and endometrial thickness in all participants were measured by transvaginal ultrasound prior to, one and two years post enrollment, respectively. Endometrial specimens were collected from all subjects with abnormal uterine bleeding during the follow-up period. We found that the uterine volume in the treatment group was greater than that in the control group, and the difference was significant (P〈0.05), but there were no significant differences in ovarian area and endometrial thickness between the two groups (P〉0.05). When the cut-off value for endometrial thickness was 7.35 ram, the sensitivity and specificity were 100% and 79.07%, respectively, and 85.71% and 93.02% when 7.55 mm was set as the cut-offduring tibolone therapy. The results indicate that low-dose tibolone therapy may postpone uterine atrophy and the cut-off value of endometrial thickness may be appropriately adjusted for curettage.
基金This study was funded by the project initiated by the China Geological Survey entitled “Remote Sensing Geological Survey of National Key Earth Zones”(DD20190536).
文摘The environmental change in the wetlands in the southern Mongolian Plateau has important impacts on the environment of North China and even the entire Northeast Asia,from which the global climate change can be understood on a large scale,especially the climate change in the Mongolian Plateau.This study extracted the information on the wetlands from three stages of remote sensing images(also referred to as RS images)of the study area,including Enhanced Thematic Mapper Plus(ETM+)images of 2000,TM images of 2010,and Landsat 8 Operational Land Imager(OLI)images of 2018.As indicated by the extraction results,the area of wetlands decreased from 796.90 km^(2) of 2000 to 666.24 km^(2) of 2018 at a rate of 7.26 km^(2)/a.The reduced area is 130.66 km^(2),which is about 16.4%reduction.And the patch number of wetlands decreased from 731 of 2000 to 316 of 2018 in the study area,approximately 56.8%reduction(415 patches),and the decrease in the area of the wetlands mainly occurred in the northwest endorheic region.In terms of wetland types,the change of the wetlands was dominated by the decrease of lacustrine wetlands,of which the area and patch number decreased by 106.2 km^(2) and 242,respectively.Furthermore,the area of the lacustrine wetlands decreased at the highest rate of 8.70 km^(2)/a in 2010‒2018.From the perspective of spatial distribution,the wetlands in the western part shrunk more notably than those in the eastern part as a whole in the study area.According to local meteorological data,the precipitation gently decreased and the temperature increased(about 1.7℃)from 1975-2018.Overall,the decrease in the area of the wetlands and the temperature rises in the study area were mainly driven by the Mongolian monsoon climate,reduction in precipitation,and human activities.
文摘Horqin Sand Land is regarded as the t ypical region for studying the probl em of desertification.The integra-tion of 3S(GIS,GPS and RS)techniques offer a most helpful meth od to study and monitor the dynamics o f desertification.Based on the data derived from3perio ds’ multitemporal Landsat TMimagery of the 1990s,the regional land use a nd dynam-ics of desertification in Horqin San d Land were studied.The main results revealed that:1)as long as the general change tendency was concerned,the deserti fication of Horqin Sand Land would co ntinue to spread;2)there was a gradual de-crease in the area of both moving sand dunes and semi-stabilized ones,whi ch meant that fruitful progress had b een made to control the desertification during the 1990s;3)as a result of unreasonable cultivation,the total area of stabilized san d dunes and grassland in the middle and western region decreased obviously.It suggested that the increasing damage caused by human was leading to the hazard of further desertification.So i n the future,it is necessary to take more effec-tive measures to control the spread o f desertification and restore the degraded ecosystems for the purpose of optimizing the global eco-environment in Horqin Sand Land.
基金Shantou Science and Technology Bureau 1st Fund of the Prevention and Treatment of New Coronavirus Pneumonia,No.2020-1-35.
文摘BACKGROUND Some patients with the novel 2019 coronavirus disease(COVID-19)display elevated liver enzymes.Some antiviral drugs that can be used against COVID-19 are associated with a risk of hepatotoxicity.AIM To analyze the clinical significance of the dynamic monitoring of the liver function of patients with COVID-19.METHODS This was a retrospective study of patients diagnosed with COVID-19 in January and February 2020 at the Department of Infection,Shantou Central Hospital.The exclusion criteria for all patients were:(1)History of chronic liver disease;(2)History of kidney disease;(3)History of coronary heart disease;(4)History of malignancy;or(5)History of diabetes.The serum levels of alanine aminotransferase(ALT),aspartate aminotransferase(AST),γ-glutamyltransferase,and total bilirubin of patients with COVID-19 were measured on days 1,3,7 and 14 after admission,and compared to non-COVID-19 patents.RESULTS Twelve patients with COVID-19(seven men and five women)and twelve controls(eight men and four women)were included.There were one,two,and nine patients with severe,mild,and moderate COVID-19,respectively.There were no differences in age and sex between the two groups(both P>0.05).No significant differences were found in albumin,ALT,AST,γ-glutamyltransferase,or total bilirubin between the controls and the patients with COVID-19 on day 1 of hospitalization(all P>0.05).Serum albumin showed a decreasing trend from days 0 to 7 of hospitalization,reaching the lowest level on day 7.Total bilirubin was higher on day 3 than on day 7.ALT,AST,andγ-glutamyltransferase did not change significantly over time.The severe patient was observed to have ALT levels of 67 U/L and AST levels of 75 U/L on day 7,ALT of 71 U/L and AST of 35 U/L on day 14,and ALT of 210 U/L and AST of 123 U/L on day 21.CONCLUSION Changes in serum liver function indicators are not obvious in the early stage of COVID-19,but clinically significant changes might be observed in severe COVID-19.
基金financially supported by the National Key R&D Program of China(Grant No.2022YFB4200705)the National Natural Science Foundation of China(Grant No.52109146)。
文摘The real-time dynamic deformation monitoring of offshore platforms under environmental excitation is crucial to their safe operation.Although Global Navigation Satellite System-Precise Point Positioning(GNSS-PPP)has been considered for this purpose,its monitoring accuracy is relatively low.Moreover,the influence of background noise on the dynamic monitoring accuracy of GNSS-PPP remains unclear.Hence,it is imperative to further validate the feasibility of GNSS-PPP for deformation monitoring of offshore platforms.To address these concerns,vibration table tests with different amplitudes and frequencies are conducted.The results demonstrate that GNSS-PPP can effectively monitor horizontal vibration displacement as low as±30 mm,which is consistent with GNSS-RTK.Furthermore,the spectral characteristic of background noise in GNSS-PPP is similar to that of GNSS-RTK(Real Time Kinematic).Building on this observation,an improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise(CEEMDAN)has been proposed to de-noise the data and enhance the dynamic monitoring accuracy of GNSS-PPP.Field monitoring application research is also undertaken,successfully extracting and analyzing the dynamic deformation of an offshore platform structure under environmental excitation using GNSS-PPP monitoring in conjunction with improved CEEMDAN de-noising.By comparing the de-noised dynamic deformation trajectories of the offshore platform during different periods,it is observed that the platform exhibits reversible alternating vibration responses under environmental excitation,with more pronounced displacement deformation in the direction of load action.The research results confirm the feasibility and potential of GNSS-PPP for dynamic deformation monitoring of offshore platforms.
文摘Dynamic monitoring is an important basic work in the sustainable exploitation and utilization of geothermal resources.It offers basic data for geothermal management department to make out the plan of geothermal resources by collecting and analyzing the outdoor dynamic monitoring data. Tianjin is one of the earliest cities in exploiting and utilizing geothermal resources,and the
基金Under the auspices of the National Natural Science Foundation of China (No. 40161004, 40361002)Guangxi Natural Science Foundation (No. 023646, 0342001-2).
文摘In order to study the spatial-temporal change and environmental management of regional karst LUCC (land use and land cover change) and its causative environmental effect-rocky desertification by integrating qualitative analysis and quantitative analysis, and relying on RS, GIS and GPS (3S) techniques, karst land rocky derification dynamic monitoring and visualization management information system (KLRD.DMVM.IS) is framed, which includes design aim and structure model, function design, database design and model system design. The model system design gives priority to dynamic monitoring, drive force diagnosis, comprehensive evaluation and decision support of karst rocky desertification. From the viewpoint of model type, mathematic expression and its meaning, the dynamic monitoring models are concretely devised to reflect the spatial and temporal changing features and the trend of karst LUCC and rocky desertification. Taking Du'an Yao Autonomic County of Guangxi as an example, the KLRD.DMVM.IS is systematically analyzed in the application of the process and trend of karst LUCC and rocky desertification in Du'an County, and it provides the technical support for the study on karst land rocky desertification.
基金financial support from the Fundamental Research Funds for the Central Universities of China (No. 2015QNB19)the financial support from the Open Fund of Key Laboratory of Safety and High-efficiency Coal Mining, Ministry of Education of China (No. JYBSYS2015107)+2 种基金the National Natural Science Foundation of China (Nos. 51404254, 41430317 and U1261202)the China Postdoctoral Science Foundation of China (No. 2014M560465)the Jiangsu Planned Projects for Postdoctoral Research Funds of China (No. 1302050B)
文摘The level of deformation development of surrounding rocks is a vital predictor to evaluate impending coal mine disasters and it is important to establish accurate measurements of the deformed status to ensure coal mine safety. Traditional deformation monitoring methods are mostly based on single parameter, in this paper, multiple approaches are integrated: firstly, both electric and elastic models are established,from which electric field distribution and seismic wave recording are calculated and finally, the resistivity profiles and source position information are determined using inversion methods, from which then the deformation and failure of mine floor are evaluated. According to the inversion results of both electric and seismic field signals, multiple-parameter dynamic monitoring of surrounding rock deformation in deep mine can be performed. The methodology is validated using numerical simulation results which shows that the multi-parameter dynamic monitoring methods have better results for surrounding rock deformation in deep mine monitoring than single parameter methods.
文摘To develop the dynamic monitoring algorithm of visual safety distance in highway, by using the highway video traffic monitoring system, the research platform of four kinds of terrain environment in plateau, mountainous area, plain and coastal area is established. Results show that through the contrast between the sample data and visibility train of thought, based on the theory of mathematical morphology, expressway visibility dynamic monitoring image information system can be established. Based on the theory of the measurement of the basic formula of visibility, the dynamic model of the optimization is established, set up 200 meters distance visual observation target system, research visual range detection algorithm process.
文摘Based on the nonlinear error equation of deformation network monitoring, the mathematical model of nonlinear dynamic optimal design of class two was put forward for the deformation network monitoring, in which the target function is the accuracy criterion and the constraint conditions are the network’s sensitivity, reliability and observing cost. Meanwhile a new non derivative solution to the nonlinear dynamic optimal design of class two was also put forward. The solving model uses the difference to stand for the first derivative of functions and solves the revised feasible direction to get the optimal solution to unknown parameters. It can not only make the solution to converge on the minimum point of the constraint problem, but decrease the calculating load.
文摘For the sake of timely appraising the working con di tion of the bridge, measuring the dynamic characteristics of the bridge structur e is very important and necessary. A GPS dynamic monitoring test was carried out in the Wuhan Baishazhou Bridge, which is one of the longest span cable-stayed bridges having been built in China. This paper introduces the experimental imple menting scheme and data processing method. The vibration characteristics of the middle span of cable-stayed bridge are availably obtained by use of the spectra l analytic approach. The measuring results are very identical to the theoretical designed values. The research demonstrates that, with GPS receiver of the high sampling rate and suitable data processing method, the vibration characteristics of the bridge structure can be determined with high accuracy.
基金Under the auspices of the key project of the National Ninth Five-year Plan (96-B02-01-07).
文摘Remote sensing technique has played an important role in land use dynamic monitoring, but as for the land use dynamic monitoring at county level, traditional remote sensing methods such as satellite imagery visual interpretation and computer classification can not meet its demand for accuracy. The result of 1:10 000 land use investigation map has high accuracy, but this method can not be used to dynamically monitor the land use because of its big expenses, long period and difficulty in updating data. In this paper, the characteristics of physiognomy, climate and the status of land use in Dehui County are taken into consideration and a set of method, which takes use of 3S techniques and applies to Northeast China Plain, is come up with. When the land use type of a land parcel changed as a whole, the date updating can be make by changing its land type ID in the attribute table in a GIS. When the land use type of an irregular area changed, GPS receivers are used to position its border. This set of method is characteristic of high accuracy and low expenses. It gets the information of land use change timely and can be used to dynamically monitor the land use. .
基金The authors are grateful for the financial support from the National Natural Science Foundation of China(Grant Nos.42177143,42277461)the Science Foundation for Distinguished Young Scholars of Sichuan Province(Grant No.2020JDJQ0011).Thanks to the Chn Energy Dadu River Hydropower Development Co.,Ltd,China Three Gorges Construction Engineering Corporation,Yalong River Hydropower Development Company,Ltd,Power China Chengdu Engineering Co.,Ltd,Power China Northwest Engineering Co.,Ltd,Power China Sinohydro Bureau 7 Co.,Ltd,China Gezhouba Group No.1 Engineering Co.,Ltd.,and the 5th Engineering Co.,Ltd.of China Railway Construction Bridge Engineering Bureau Group for the support and assistance.
文摘The underground hydropower projects in Southwest China is characterized by large excavation sizes,high geostresses,complicated geological conditions and multiple construction processes.Various disasters such as collapses,large deformations,rockbursts are frequently encountered,resulting in serious casualties and huge economic losses.This review mainly presents some representative results on microseismic(MS)monitoring and forecasting for disasters in hydropower underground engineering.First,a set of new denoising,spectral analysis,and location methods were developed for better identification and location of MS signals.Then,the tempo-spatial characteristics of MS events were analyzed to understand the relationship between field construction and damages of surrounding rocks.Combined with field construction,geological data,numerical simulation and parametric analysis of MS sources,the focal mechanism of MS events was revealed.A damage constitutive model considering MS fracturing size was put forward and feedback analysis considering the MS damage of underground surrounding rocks was conducted.Next,an MS multi-parameter based risk assessment and early warning method for dynamic disasters were proposed.The technology for control of the damage and deformation of underground surrounding rocks was proposed for underground caverns.Finally,two typical underground powerhouses were selected as case studies.These achievements can provide significant references for prevention and control of dynamic disasters for underground engineering with similar complicated geological conditions.
基金supported by the Research and Development Center of Transport Industry of New Generation of Artificial Intelligence Technology(Grant No.202202H)the National Key R&D Program of China(Grant No.2019YFB1600702)the National Natural Science Foundation of China(Grant Nos.51978600&51808336).
文摘Structural Health Monitoring(SHM)systems have become a crucial tool for the operational management of long tunnels.For immersed tunnels exposed to both traffic loads and the effects of the marine environment,efficiently identifying abnormal conditions from the extensive unannotated SHM data presents a significant challenge.This study proposed amodel-based approach for anomaly detection and conducted validation and comparative analysis of two distinct temporal predictive models using SHM data from a real immersed tunnel.Firstly,a dynamic predictive model-based anomaly detectionmethod is proposed,which utilizes a rolling time window for modeling to achieve dynamic prediction.Leveraging the assumption of temporal data similarity,an interval prediction value deviation was employed to determine the abnormality of the data.Subsequently,dynamic predictive models were constructed based on the Autoregressive Integrated Moving Average(ARIMA)and Long Short-Term Memory(LSTM)models.The hyperparameters of these models were optimized and selected using monitoring data from the immersed tunnel,yielding viable static and dynamic predictive models.Finally,the models were applied within the same segment of SHM data,to validate the effectiveness of the anomaly detection approach based on dynamic predictive modeling.A detailed comparative analysis discusses the discrepancies in temporal anomaly detection between the ARIMA-and LSTM-based models.The results demonstrated that the dynamic predictive modelbased anomaly detection approach was effective for dealing with unannotated SHM data.In a comparison between ARIMA and LSTM,it was found that ARIMA demonstrated higher modeling efficiency,rendering it suitable for short-term predictions.In contrast,the LSTM model exhibited greater capacity to capture long-term performance trends and enhanced early warning capabilities,thereby resulting in superior overall performance.
基金funded by National Natural Science Foundation Project (40801077)Ministry of Education Key Project (209100)+1 种基金Natural Science Foundation of Chongqing ( CSTC, 2008BB7367 )Chongqing Municipal Education Commission of Science and Technology Research Grant Project (KJ070811)~~
文摘The positioning combined with multi-functioning and interactive mechanics in dynamic testing of slender bridges are treated in present paper. The approach takes into account multiple functions in dynamic testing of slender bridges constructed of thin-walled structural members with their hierarchical configuration. Theoretical, numerical and experimental in situ assessments of the problem are presented. Some results of the application in situ are submitted.