期刊文献+
共找到5,224篇文章
< 1 2 250 >
每页显示 20 50 100
Equivalent Conditions of Complete Convergence for Weighted Sums of Sequences of i.i.d.Random Variables under Sublinear Expectations
1
作者 XU Mingzhou CHENG Kun 《应用概率统计》 北大核心 2025年第3期339-352,共14页
The complete convergence for weighted sums of sequences of independent,identically distributed random variables under sublinear expectation space is studied.By moment inequality and truncation methods,we establish the... The complete convergence for weighted sums of sequences of independent,identically distributed random variables under sublinear expectation space is studied.By moment inequality and truncation methods,we establish the equivalent conditions of complete convergence for weighted sums of sequences of independent,identically distributed random variables under sublinear expectation space.The results complement the corresponding results in probability space to those for sequences of independent,identically distributed random variables under sublinear expectation space. 展开更多
关键词 complete convergence weighted sums i.i.d.random variables sublinear expectation
在线阅读 下载PDF
Complete f-Moment Convergence for Sung’s Type Weighted Sums of Negatively Superadditive Dependent Random Variables
2
作者 HU Xueping WANG Liuliu +1 位作者 HU Ke XU Zhonghao 《应用概率统计》 北大核心 2025年第4期585-601,共17页
In this paper,by utilizing the Marcinkiewicz-Zygmund inequality and Rosenthal-type inequality of negatively superadditive dependent(NSD)random arrays and truncated method,we investigate the complete f-moment convergen... In this paper,by utilizing the Marcinkiewicz-Zygmund inequality and Rosenthal-type inequality of negatively superadditive dependent(NSD)random arrays and truncated method,we investigate the complete f-moment convergence of NSD random variables.We establish and improve a general result on the complete f-moment convergence for Sung’s type randomly weighted sums of NSD random variables under some general assumptions.As an application,we show the complete consistency for the randomly weighted estimator in a nonparametric regression model based on NSD errors. 展开更多
关键词 Marcinkiewicz-Zygmund inequality Rosenthal-type inequality Sung’s type randomly weighted sums negatively superadditive dependent random variables complete f-moment convergence
在线阅读 下载PDF
Influence of ambient geochemical and microbiological variables on the bacterial diversity in a cold seep ecosystem in North Indian Ocean
3
作者 Delcy R.Nazareth Maria Judith Gonsalves Nitisha Sangodkar 《Geoscience Frontiers》 2025年第3期153-163,共11页
Cold seeps are oases for biological communities on the sea floor around hydrocarbon emission pathways.Microbial utilization of methane and other hydrocarbons yield products that fuel rich chemosynthetic communities at... Cold seeps are oases for biological communities on the sea floor around hydrocarbon emission pathways.Microbial utilization of methane and other hydrocarbons yield products that fuel rich chemosynthetic communities at these sites.One such site in the cold seep ecosystem of Krishna-Godavari basin(K-G basin)along the east coast of India,discovered in Feb 2018 at a depth of 1800 m was assessed for its bacterial diversity.The seep bacterial communities were dominated by phylum Proteobacteria(57%),Firmicutes(16%)and unclassified species belonging to the family Helicobacteriaceae.The surface sediments of the seep had maximum OTUs(operational taxonomic units)(2.27×10^(3))with a Shannon alpha diversity index of 8.06.In general,environmental parameters like total organic carbon(p<0.01),sulfate(p<0.001),sulfide(p<0.05)and methane(p<0.01)were responsible for shaping the bacterial community of the cold seep ecosystem in the K-G Basin.Environmental parameters play a significant role in changing the bacterial diversity richness between different cold seep environments in the oceans. 展开更多
关键词 Sediments Environmental variables PROTEOBACTERIA Cold seep ecosystem Organic matter
在线阅读 下载PDF
Mapping soil organic carbon in fragmented agricultural landscapes:The efficacy and interpretability of multi-category remote sensing variables
4
作者 Yujiao Wei Yiyun Chen +6 位作者 Jiaxue Wang Peiheng Yu Lu Xu Chi Zhang Huanfeng Shen Yaolin Liu Ganlin Zhang 《Journal of Integrative Agriculture》 2025年第11期4395-4414,共20页
Accurately mapping the spatial distribution of soil organic carbon(SOC)is crucial for guiding agricultural management and improving soil carbon sequestration,especially in fragmented agricultural landscapes.Although r... Accurately mapping the spatial distribution of soil organic carbon(SOC)is crucial for guiding agricultural management and improving soil carbon sequestration,especially in fragmented agricultural landscapes.Although remote sensing provides spatially continuous environmental information about heterogeneous agricultural landscapes,its relationship with SOC remains unclear.In this study,we hypothesized that multi-category remote sensing-derived variables can enhance our understanding of SOC variation within complex landscape conditions.Taking the Qilu Lake watershed in Yunnan,China,as a case study area and based on 216 topsoil samples collected from irrigation areas,we applied the extreme gradient boosting(XGBoost)model to investigate the contributions of vegetation indices(VI),brightness indices(BI),moisture indices(MI),and spectral transformations(ST,principal component analysis and tasseled cap transformation)to SOC mapping.The results showed that ST contributed the most to SOC prediction accuracy,followed by MI,VI,and BI,with improvements in R2 of 29.27,26.83,19.51,and 14.43%,respectively.The dominance of ST can be attributed to the fact that it contains richer remote sensing spectral information.The optimal SOC prediction model integrated soil properties,topographic factors,location factors,and landscape metrics,as well as remote sensing-derived variables,and achieved RMSE and MAE of 15.05 and 11.42 g kg-1,and R2 and CCC of 0.57 and 0.72,respectively.The Shapley additive explanations deciphered the nonlinear and threshold effects that exist between soil moisture,vegetation status,soil brightness and SOC.Compared with traditional linear regression models,interpretable machine learning has advantages in prediction accuracy and revealing the influences of variables that reflect landscape characteristics on SOC.Overall,this study not only reveals how remote sensing-derived variables contribute to our understanding of SOC distribution in fragmented agricultural landscapes but also clarifies their efficacy.Through interpretable machine learning,we can further elucidate the causes of SOC variation,which is important for sustainable soil management and agricultural practices. 展开更多
关键词 soil organic carbon remote sensing-derived variables Shapley additive explanations efficacy and interpretability fragmented agricultural landscapes
在线阅读 下载PDF
On α-Bloch Functions in Several Complex Variables
5
作者 ZHU Ting YANG Liu 《Chinese Quarterly Journal of Mathematics》 2025年第1期93-102,共10页
In this paper,we establish characterizations of α-Bloch functions and little α-Bloch functions on the unit ball as well as the unit polydisk of C^(m),which generalize and improve results of Aulaskari-Lappan,Minda,Au... In this paper,we establish characterizations of α-Bloch functions and little α-Bloch functions on the unit ball as well as the unit polydisk of C^(m),which generalize and improve results of Aulaskari-Lappan,Minda,Aulaskari-Wulan,and Wu.Some examples are also given to complement our theory. 展开更多
关键词 α-Bloch function Littleα-Bloch function Several complex variables Partial derivative
在线阅读 下载PDF
Complete q-Order Moment Convergence of Moving Average Processes Generated by Negatively Dependent Random Variables under Sub-Linear Expectations
6
作者 Mingzhou XU 《Journal of Mathematical Research with Applications》 2025年第3期395-410,共16页
Assume that{a_(i),−∞<i<∞}is an absolutely summable sequence of real numbers.We establish the complete q-order moment convergence for the partial sums of moving average processes{X_(n)=Σ_(i=−∞)^(∞)a_(i)Y_(i+... Assume that{a_(i),−∞<i<∞}is an absolutely summable sequence of real numbers.We establish the complete q-order moment convergence for the partial sums of moving average processes{X_(n)=Σ_(i=−∞)^(∞)a_(i)Y_(i+n),n≥1}under some proper conditions,where{Yi,-∞<i<∞}is a doubly infinite sequence of negatively dependent random variables under sub-linear expectations.These results extend and complement the relevant results in probability space. 展开更多
关键词 moving average processes negatively dependent random variables complete moment convergence sub-linear expectations
原文传递
On the Spatial Distribution of Luminous Blue Variables in the Galaxy M33
7
作者 A.Kostenkov S.Fabrika +6 位作者 A.Kaldybekova S.Fedorchenko Y.Solovyeva E.Dedov A.Sarkisyan A.Vinokurov O.Sholukhova 《Research in Astronomy and Astrophysics》 2025年第4期136-149,共14页
In the current paper,we present a study of the spatial distribution of luminous blue variables(LBVs)and various LBV candidates(c LBVs)with respect to OB associations in the galaxy M33.The identification of blue star g... In the current paper,we present a study of the spatial distribution of luminous blue variables(LBVs)and various LBV candidates(c LBVs)with respect to OB associations in the galaxy M33.The identification of blue star groups was based on the LGGS data and was carried out by two clustering algorithms with initial parameters determined during simulations of random stellar fields.We have found that the distribution of distances to the nearest OB association obtained for the LBV/c LBV sample is close to that for massive stars with Minit>20 M⊙and WolfRayet stars.This result is in good agreement with the standard assumption that LBVs represent an intermediate stage in the evolution of the most massive stars.However,some objects from the LBV/cLBV sample,particularly Fe II-emission stars,demonstrated severe isolation compared to other massive stars,which,together with certain features of their spectra,implicitly indicates that the nature of these objects and other LBVs/cLBVs may differ radically. 展开更多
关键词 stars:massive stars:evolution stars:winds outflows stars:variables:S Doradus (stars:)binaries:general galaxies:individual(M33)
在线阅读 下载PDF
Loop Peeling Based on Quasi-Invariance/Induction Variables 被引量:1
8
作者 Litong Song, Robert Glück, Yoshihiko Futamura Institute for Software Production Technology, Waseda University, Okubo 3 4 1, Shinjuku ku Tokyo 169 8555, Japan 《Wuhan University Journal of Natural Sciences》 CAS 2001年第Z1期362-367,共6页
Loop optimization plays an important role in compiler optimization and program transformation. Many sophisticated techniques such as loop invariance code motion have been developed. Loop peeling is a technique to ass... Loop optimization plays an important role in compiler optimization and program transformation. Many sophisticated techniques such as loop invariance code motion have been developed. Loop peeling is a technique to assist parallelization of loops by unfolding loops a few times. This paper introduces a novel technique called loop peeling based on quasi invariance/induction variables. It aims at finding a general and automatic method to derive how many times a given loop should be peeled. Our technique allows for a number of iterations before some variables assigned inside a given loop become invariance or induction variables. In this paper we define the notion of quasi invariance/induction variables, present an algorithm for statically computing the optimal peeling length of a given loop. Our technique can increase the accuracy of program analyses, improve the effectiveness of loop peeling and is well suited as supporting other optimization techniques in the context of supercomputers. 展开更多
关键词 loop peeling parallelization induction variables quasi induction variables quasi invariance variables
在线阅读 下载PDF
Inequalities of Maximum of Partial Sums and Convergence Rates in the Strong Laws for ρ^-mixing Random Variables 被引量:1
9
作者 TAN Cheng-liang WU Qun-ying HE Yan-mei 《Chinese Quarterly Journal of Mathematics》 CSCD 2011年第1期114-119,共6页
In this paper,we establish a Rosenthal-type inequality of partial sums for ρ~mixing random variables.As its applications,we get the complete convergence rates in the strong laws for ρ^-mixing random variables.The re... In this paper,we establish a Rosenthal-type inequality of partial sums for ρ~mixing random variables.As its applications,we get the complete convergence rates in the strong laws for ρ^-mixing random variables.The result obtained extends the corresponding result. 展开更多
关键词 convergence rates rosenthal type inequality ρ—-mixing random variables ρ~mixing random variables negatively associated random variables
在线阅读 下载PDF
Optimizing Fine-Tuning in Quantized Language Models:An In-Depth Analysis of Key Variables
10
作者 Ao Shen Zhiquan Lai +1 位作者 Dongsheng Li Xiaoyu Hu 《Computers, Materials & Continua》 SCIE EI 2025年第1期307-325,共19页
Large-scale Language Models(LLMs)have achieved significant breakthroughs in Natural Language Processing(NLP),driven by the pre-training and fine-tuning paradigm.While this approach allows models to specialize in speci... Large-scale Language Models(LLMs)have achieved significant breakthroughs in Natural Language Processing(NLP),driven by the pre-training and fine-tuning paradigm.While this approach allows models to specialize in specific tasks with reduced training costs,the substantial memory requirements during fine-tuning present a barrier to broader deployment.Parameter-Efficient Fine-Tuning(PEFT)techniques,such as Low-Rank Adaptation(LoRA),and parameter quantization methods have emerged as solutions to address these challenges by optimizing memory usage and computational efficiency.Among these,QLoRA,which combines PEFT and quantization,has demonstrated notable success in reducing memory footprints during fine-tuning,prompting the development of various QLoRA variants.Despite these advancements,the quantitative impact of key variables on the fine-tuning performance of quantized LLMs remains underexplored.This study presents a comprehensive analysis of these key variables,focusing on their influence across different layer types and depths within LLM architectures.Our investigation uncovers several critical findings:(1)Larger layers,such as MLP layers,can maintain performance despite reductions in adapter rank,while smaller layers,like self-attention layers,aremore sensitive to such changes;(2)The effectiveness of balancing factors depends more on specific values rather than layer type or depth;(3)In quantization-aware fine-tuning,larger layers can effectively utilize smaller adapters,whereas smaller layers struggle to do so.These insights suggest that layer type is a more significant determinant of fine-tuning success than layer depth when optimizing quantized LLMs.Moreover,for the same discount of trainable parameters,reducing the trainable parameters in a larger layer is more effective in preserving fine-tuning accuracy than in a smaller one.This study provides valuable guidance for more efficient fine-tuning strategies and opens avenues for further research into optimizing LLM fine-tuning in resource-constrained environments. 展开更多
关键词 Large-scale Language Model Parameter-Efficient Fine-Tuning parameter quantization key variable trainable parameters experimental analysis
在线阅读 下载PDF
Multiple attribute decision making method based on trapezoid fuzzy linguistic variables 被引量:4
11
作者 梁雪春 陈森发 《Journal of Southeast University(English Edition)》 EI CAS 2008年第4期478-481,共4页
The problem of multiple attribute decision making under fuzzy linguistic environments, in which decision makers can only provide their preferences (attribute values)in the form of trapezoid fuzzy linguistic variable... The problem of multiple attribute decision making under fuzzy linguistic environments, in which decision makers can only provide their preferences (attribute values)in the form of trapezoid fuzzy linguistic variables(TFLV), is studied. The formula of the degree of possibility between two TFLVs is defined, and some of its characteristics are studied. Based on the degree of possibility of fuzzy linguistic variables, an approach to ranking the decision alternatives in multiple attribute decision making with TFLV is developed. The trapezoid fuzzy linguistic weighted averaging (TFLWA) operator method is utilized to aggregate the decision information, and then all the alternatives are ranked by comparing the degree of possibility of TFLV. The method can carry out linguistic computation processes easily without loss of linguistic information, and thus makes the decision results reasonable and effective. Finally, the implementation process of the proposed method is illustrated and analyzed by a practical example. 展开更多
关键词 trapezoid fuzzy linguistic variables degree of possibility multiple attribute decision making
在线阅读 下载PDF
Strong Limit Theorems for Weighted Sums of Widely Orthant Dependent Random Variables 被引量:3
12
作者 Dehua QIU Tienchung HU 《Journal of Mathematical Research with Applications》 CSCD 2014年第1期105-113,共9页
Strong limit theorems are established for weighted sums of widely orthant dependent(WOD) random variables. As corollaries, the strong limit theorems for weighted sums of extended negatively orthant dependent(ENOD)... Strong limit theorems are established for weighted sums of widely orthant dependent(WOD) random variables. As corollaries, the strong limit theorems for weighted sums of extended negatively orthant dependent(ENOD) random variables are also obtained, which extend and improve the related known works in the literature. 展开更多
关键词 widely orthant dependent (WOD) random variables extended negatively orthantdependent (ENOD) random variables weighted sums strong limit theorem.
原文传递
Construction of crash prediction model of freeway basic segment based on interactive influence of explanatory variables
13
作者 王晓飞 李新伟 +2 位作者 符锌砂 赵立萱 刘小峰 《Journal of Southeast University(English Edition)》 EI CAS 2015年第2期276-281,共6页
In order to improve the prediction precision of the safety performance function (SPF) of freeway basic segments, design and crash data of 640 segments are collected from different institutions. Three negative binomi... In order to improve the prediction precision of the safety performance function (SPF) of freeway basic segments, design and crash data of 640 segments are collected from different institutions. Three negative binomial (NB) regression models and three generalized negative binomial (GNB) regression models are built to prove that the interactive influence of explanatory variables plays an important role in fitting goodness. The effective use of the GNB model in analyzing the interactive influence of explanatory variables and predicting freeway basic segments is demonstrated. Among six models, the two models (one is the NB model and the other is the GNB model. ) which consider the interactive influence of the annual average daily traffic (AADT) and length are more reasonable for predicting results. Furthermore, a comprehensive study is carried out to prove that when considering the interactive influence, the NB and GNB models have almost the same fitting performance in estimating the crashes, among which the GNB model is slightly better for prediction performance. 展开更多
关键词 CRASH FREEWAY safety performance function( SPF interactive influence of explanatory variables generalized negative binomial (GNB)
在线阅读 下载PDF
Strong Law of Large Numbers for Array of Rowwise AANA Random Variables 被引量:1
14
作者 CHEN Zhi-yong LIU Ting-ting WANG Xue-jun LI Xiao-qin 《Chinese Quarterly Journal of Mathematics》 CSCD 2014年第4期475-485,共11页
In this article, the strong laws of large numbers for array of rowwise asymptotically almost negatively associated(AANA) random variables are studied. Some sufficient conditions for strong laws of large numbers for ar... In this article, the strong laws of large numbers for array of rowwise asymptotically almost negatively associated(AANA) random variables are studied. Some sufficient conditions for strong laws of large numbers for array of rowwise AANA random variables are presented without assumption of identical distribution. Our results extend the corresponding ones for independent random variables to case of AANA random variables. 展开更多
关键词 AANA random variables array of rowwise AANA random variables strong law of large numbers
在线阅读 下载PDF
Evaluation of CRU TS, GPCC, AgMERRA, and AgCFSR meteorological datasets for estimating climate and crop variables: A case study of maize in Qazvin Province, Iran
15
作者 Faraz GORGIN PAVEH Hadi RAMEZANI ETEDALI Brian COLLINS 《Journal of Arid Land》 SCIE CSCD 2022年第12期1361-1376,共16页
In the past few decades,meteorological datasets from remote sensing techniques in agricultural and water resources management have been used by various researchers and managers.Based on the literature,meteorological d... In the past few decades,meteorological datasets from remote sensing techniques in agricultural and water resources management have been used by various researchers and managers.Based on the literature,meteorological datasets are not more accurate than synoptic stations,but their various advantages,such as spatial coverage,time coverage,accessibility,and free use,have made these techniques superior,and sometimes we can use them instead of synoptic stations.In this study,we used four meteorological datasets,including Climatic Research Unit gridded Time Series(CRU TS),Global Precipitation Climatology Centre(GPCC),Agricultural National Aeronautics and Space Administration Modern-Era Retrospective Analysis for Research and Applications(AgMERRA),Agricultural Climate Forecast System Reanalysis(AgCFSR),to estimate climate variables,i.e.,precipitation,maximum temperature,and minimum temperature,and crop variables,i.e.,reference evapotranspiration,irrigation requirement,biomass,and yield of maize,in Qazvin Province of Iran during 1980-2009.At first,data were gathered from the four meteorological datasets and synoptic station in this province,and climate variables were calculated.Then,after using the AquaCrop model to calculate the crop variables,we compared the results of the synoptic station and meteorological datasets.All the four meteorological datasets showed strong performance for estimating climate variables.AgMERRA and AgCFSR had more accurate estimations for precipitation and maximum temperature.However,their normalized root mean square error was inferior to CRU for minimum temperature.Furthermore,they were all very efficient for estimating the biomass and yield of maize in this province.For reference evapotranspiration and irrigation requirement CRU TS and GPCC were the most efficient rather than AgMERRA and AgCFSR.But for the estimation of biomass and yield,all the four meteorological datasets were reliable.To sum up,GPCC and AgCFSR were the two best datasets in this study.This study suggests the use of meteorological datasets in water resource management and agricultural management to monitor past changes and estimate recent trends. 展开更多
关键词 climate variables crop variables meteorological datasets precipitation reference evapotranspiration irrigation requirement Iran
在线阅读 下载PDF
The Relations of Change Rate of Constitutive Variables for the Freezing and Thawing of Water Saturated Porous Media
16
作者 陆宏轮 《Journal of Modern Transportation》 1999年第2期173-180,共8页
The relations of change rate of an independent variable, volumetric strain of the porous skeleton, with the change rates of a kind of constitutive variables, such as porosity, volumetric strain of the solid matrix, ar... The relations of change rate of an independent variable, volumetric strain of the porous skeleton, with the change rates of a kind of constitutive variables, such as porosity, volumetric strain of the solid matrix, are derived from the definition of the porosity of water saturated porous media; and the relations of the change rates of another two independent variables, pressure of the pore liquid water and temperature, with the change rates of another kind of constitutive variables, such as pressure of the pore ice, average pressure of the pore liquid water and ice, and average stress of the solid matrix, are obtained from the Clausius Clapeyron relation in the process of freezing or thawing, definitions of the average pore pressure and effective stress. Based on the hypothesis of linear thermoelasticity, principle of effective stress and these relations, the change rates of all constitutive variables may be described with the change rates of the three independent variables. 展开更多
关键词 change rate constitutive variables independent variables freezing and thawing porous media
在线阅读 下载PDF
Convergence Properties for Arrays of Rowwise φ-Mixing Random Variables
17
作者 Xiaoqin LI 《Journal of Mathematical Research with Applications》 CSCD 2014年第5期608-618,共11页
Convergence properties for arrays of rowwise φ-mixing random variables are studied. As an application, the Chung-type strong law of large numbers for arrays of rowwise φ-mixing random variables is obtained. Our resu... Convergence properties for arrays of rowwise φ-mixing random variables are studied. As an application, the Chung-type strong law of large numbers for arrays of rowwise φ-mixing random variables is obtained. Our results extend the corresponding ones for independent random variables to the case of φ-mixing random variables. 展开更多
关键词 φ-mixing random variables arrays of rowwise φ-mixing random variables stronglaw of large numbers.
原文传递
The Influences of Affective Variables on and Implications for English Teaching and Learning
18
作者 张莹 《海外英语》 2014年第23期286-288,共3页
Admittedly cognitive variables such as intelligence and aptitude exert great impact on English learning. Affective variables, however, are of intense importance in determining English learning as well, because affect ... Admittedly cognitive variables such as intelligence and aptitude exert great impact on English learning. Affective variables, however, are of intense importance in determining English learning as well, because affect is a starting machine that sets the learning mechanism in motion and learning will run into difficulty if affect does not work properly. Besides, there is mounting interest in exploring the affective domain. Therefore, this paper focuses upon the analyses of four affective variables(attitude, motivation, self-esteem and anxiety) that have bearings on English learning and sets forth Implications for English teaching. 展开更多
关键词 AFFECTIVE variables ENGLISH TEACHING and learning
在线阅读 下载PDF
Establishment and Optimization of Status Assessment Variables for Heavy Haul Railway Line Service Performance
19
作者 Changfan Zhang Wendong Kong +2 位作者 Zhongmei Wang Lin Jia Shou Chen 《Journal of Transportation Technologies》 2023年第4期731-745,共15页
In order to address the issues of complex system structure and variable selection difficulty for the current heavy haul railway line status evaluation system, a three-category and three-layer heavy-haul line status ev... In order to address the issues of complex system structure and variable selection difficulty for the current heavy haul railway line status evaluation system, a three-category and three-layer heavy-haul line status evaluation variable set construction and reduction optimization method is proposed. Firstly, the status of heavy haul railway line is analyzed, and an initial set of evaluation variables affecting the line status is constructed. Then, based on the association rule and the principal component analysis method, key variables are extracted from the initial variable set to establish the evaluation system. Finally, this method is verified with actual data of a line. The results show that the service performance of heavy haul railway line can still be evaluated accurately when the evaluation variables are reduced by 60% in the proposed method. 展开更多
关键词 Set of variables Key variables Heavy Haul Railway Line Association Rule Principal Component Analysis
在线阅读 下载PDF
Early Warning of Acute Altitude Sickness by Physiological Variables and Noninvasive Cardiovascular Indicators 被引量:12
20
作者 Zongbin Li Chunwei Liu +5 位作者 Jun Guo Yajun Shi Yang Li Jinli Wang Jing Wang Yundai Chen 《Chinese Medical Sciences Journal》 CAS CSCD 2020年第1期13-19,共7页
Objective To examine if the variations at sea level would be able to predict subsequent susceptibility to acute altitude sickness in subjects upon a rapid ascent to high altitude.Methods One hundred and six Han nation... Objective To examine if the variations at sea level would be able to predict subsequent susceptibility to acute altitude sickness in subjects upon a rapid ascent to high altitude.Methods One hundred and six Han nationality male individuals were recruited to this research.Dynamic electrocardiogram,treadmill exercise test,echocardiography,routine blood examination and biochemical analysis were performed when subjects at sea level and entering the plateau respectively.Then multiple regression analysis was performed to construct a multiple linear regression equation using the Lake Louise Score as dependent variable to predict the risk factors at sea level related to acute mountain sickness(AMS).Results Approximately 49.05%of the individuals developed AMS.The tricuspid annular plane systolic excursion(22.0+2.66 vs.23.2+3.19 mm,t=l.998,P=0.048)was significantly lower in the AMS group at sea level,while count of eosinophil[(0.264+0.393)×109/L vs.(0.126+0.084)×109/L,t=-2.040,P—0.045],percentage of diflerences exceeding 50 ms between adjacent normal number of intervals(PNN50,9.66%±5.40%vs.6.98%±5.66%,t=-2.229,P=0.028)and heart rate variability triangle index(57.1+16.1 vs.50.6+12.7,t=-2.271,P=0.025)were significantly higher.After acute exposure to high altitude,C-reactive protein(0.098+0.103 vs.0.062+0.045 g/L,t=-2.132,P=0.037),aspartate aminotransferase(19.7+6.7275.17,3±3.95 U/L,t=-2.231,P=0.028)and creatinine(85.1±12.9 vs.77.7±11.2 mmol/L,t=3.162,P=0.002)were significantly higher in the AMS group,while alkaline phosphatase(71.7+18.2 vs.80.6+20.2 U/L,t=2.389,P=0.019),standard deviation of normal-to-normal RR intervals(126.5+35.9 vs.143.3+36.4 ms,t—2.320,P—0.022),ejection time(276.9+50.8 vs.313.8+48.9 ms,t—3.641,P—0.001)and heart rate variability triangle index(37.1+12.9 vs.41.9+11.1,t=2.O2O,P=0.047)were significantly lower.Using the Lake Louise Score as the dependent variable,prediction equation were established to estimate AMS:Lake Louise Score=3.783+0.281Xeosinophil-0.219Xalkaline phosphatase+O.O32XPNN50.Conclusions We elucidated the differences of pl^siological variables as well as noninvasive cardiovascular indicators for subjects after high altitude exposure compared with those at sea level.We also created an acute high altitude reaction early warning equation based on the physiological variables and noninvasive cardiovascular indicators at sea level. 展开更多
关键词 ACUTE ALTITUDE sickness PHYSIOLOGICAL variables NONINVASIVE CARDIOVASCULAR INDICATORS ACUTE high ALTITUDE exposure early warning
暂未订购
上一页 1 2 250 下一页 到第
使用帮助 返回顶部