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Data-driven methods for predicting the representative temperature of bridge cable based on limited measured data
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作者 WANG Fen DAI Gong-lian +2 位作者 HE Chang-lin GE Hao RAO Hui-ming 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第9期3168-3186,共19页
Cable-stayed bridges have been widely used in high-speed railway infrastructure.The accurate determination of cable’s representative temperatures is vital during the intricate processes of design,construction,and mai... Cable-stayed bridges have been widely used in high-speed railway infrastructure.The accurate determination of cable’s representative temperatures is vital during the intricate processes of design,construction,and maintenance of cable-stayed bridges.However,the representative temperatures of stayed cables are not specified in the existing design codes.To address this issue,this study investigates the distribution of the cable temperature and determinates its representative temperature.First,an experimental investigation,spanning over a period of one year,was carried out near the bridge site to obtain the temperature data.According to the statistical analysis of the measured data,it reveals that the temperature distribution is generally uniform along the cable cross-section without significant temperature gradient.Then,based on the limited data,the Monte Carlo,the gradient boosted regression trees(GBRT),and univariate linear regression(ULR)methods are employed to predict the cable’s representative temperature throughout the service life.These methods effectively overcome the limitations of insufficient monitoring data and accurately predict the representative temperature of the cables.However,each method has its own advantages and limitations in terms of applicability and accuracy.A comprehensive evaluation of the performance of these methods is conducted,and practical recommendations are provided for their application.The proposed methods and representative temperatures provide a good basis for the operation and maintenance of in-service long-span cable-stayed bridges. 展开更多
关键词 cable-stayed bridges representative temperature gradient boosted regression trees(GBRT)method field test limited measured data
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GGE biplot analysis of yield stability and test location representativeness in proso millet (Panicum miliaceum L.) genotypes 被引量:14
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作者 ZHANG Pan-pan SONG Hui +8 位作者 KE Xi-wang JIN Xi-jun YIN Li-hua LIU Yang QU Yang SU Wang FENG Nai-jie ZHENG Dian-feng FENG Bai-li 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2016年第6期1218-1227,共10页
The experiments were conducted for three consecutive years across 14 locations using 9 non-waxy proso millet genotypes and 16 locations using 7 waxy proso millet genotypes in China. The objectives of this study were t... The experiments were conducted for three consecutive years across 14 locations using 9 non-waxy proso millet genotypes and 16 locations using 7 waxy proso millet genotypes in China. The objectives of this study were to analyze yield stability and adaptability of proso millets and to evaluate the discrimination and representativeness of locations by analysis of vari- ance (ANOVA) and genotype and genotype by environment interaction (GGE) biplot methods. Grain yields of proso millet genotypes were significantly influenced by environment (E), genotype (G) and their interaction (GxE) (P〈0.1%). GxE inter- action effect was six times higher than G effect in non-waxy group and seven times in waxy group. N04-339 in non-waxy and Neimi 6 (NM6) in waxy showed higher grain yields and stability compared with other genotypes. Also, Neimi 9 (NM9, a non-waxy cultivar) and 90322-2-33 (a waxy cultivar) showed higher adaptability in 7 and in 11 locations, respectively. For non-waxy, Dalat, Inner Mongolia (E2) and Wuzhai, Shanxi (E5) were the best sites among all the locations for maximizing the variance among candidate cultivars, and Yanchi, Ningxia (El0) had the best representativeness. Wuzhai, Shanxi (e9) and Yanchi, Ningxia (e14) were the best representative locations, and Baicheng, Jilin (e2) was better discriminating location than others for waxy genotypes. Based on our results, El0 and e14 have enhanced efficiency and accuracy for non-waxy genotypes and waxy genotypes selection, respectively in national regional test of proso millet varieties. 展开更多
关键词 proso millet GGE biplot yield stability test location representativeness
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Mining Representative Subset Based on Fuzzy Clustering 被引量:1
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作者 ZHOU Hongfang FENG Boqin LU Lintao 《Wuhan University Journal of Natural Sciences》 CAS 2007年第5期799-803,共5页
Two new concepts-fuzzy mutuality and average fuzzy entropy are presented. Then based on these concepts, a new algorithm-RSMA (representative subset mining algorithm) is proposed, which can abstract representative su... Two new concepts-fuzzy mutuality and average fuzzy entropy are presented. Then based on these concepts, a new algorithm-RSMA (representative subset mining algorithm) is proposed, which can abstract representative subset from massive data. To accelerate the speed of producing representative subset, an improved algorithm-ARSMA(accelerated representative subset mining algorithm) is advanced, which adopt combining putting forward with backward strategies. In this way, the performance of the algorithm is improved. Finally we make experiments on real datasets and evaluate the representative subset. The experiment shows that ARSMA algorithm is more excellent than RandomPick algorithm either on effectiveness or efficiency. 展开更多
关键词 representative subset fuzzy mutuality fuzzy entropy COVERAGE REDUNDANCY
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Understanding the spatial representativeness of air quality monitoring network and its application to PM_(2.5)in the China's Mainland 被引量:3
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作者 Ling Su Chanchan Gao +7 位作者 Xiaoli Ren Fengying Zhang Shanshan Cao Shiqing Zhang Tida Chen Mengqing Liu Bingchuan Ni Min Liu 《Geoscience Frontiers》 SCIE CAS CSCD 2022年第3期130-138,共9页
Air pollution has seriously endangered human health and the natural ecosystem during the last decades.Air quality monitoring stations(AQMS)have played a critical role in providing valuable data sets for recording regi... Air pollution has seriously endangered human health and the natural ecosystem during the last decades.Air quality monitoring stations(AQMS)have played a critical role in providing valuable data sets for recording regional air pollutants.The spatial representativeness of AQMS is a critical parameter when choosing the location of stations and assessing effects on the population to long-term exposure to air pollution.In this paper,we proposed a methodological framework for assessing the spatial representativeness of the regional air quality monitoring network and applied it to ground-based PM_(2.5)observation in the mainland of China.Weighted multidimensional Euclidean distance between each pixel and the stations was used to determine the representativeness of the existing monitoring network.In addition,the K-means clustering method was adopted to improve the spatial representativeness of the existing AQMS.The results showed that there were obvious differences among the representative area of 1820 stations in the mainland of China.The monitoring stations could well represent the PM_(2.5)spatial distribution of the entire region,and the effectively represented area(i.e.the area where the Euclidean distance between the pixels and the stations was lower than the average value)accounted for 67.32%of the total area and covered 93.12%of the population.Forty additional stations were identified in the Northwest,North China,and Northeast regions,which could improve the spatial representativeness by 14.31%. 展开更多
关键词 PM_(2.5) Euclidean distance Spatial representativeness China
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Reliability analysis of slopes considering spatial variability of soil properties based on efficiently identified representative slip surfaces 被引量:16
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作者 Bin Wang Leilei Liu +1 位作者 Yuehua Li Quan Jiang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2020年第3期642-655,共14页
Slope reliability analysis considering inherent spatial variability(ISV)of soil properties is timeconsuming when response surface method(RSM)is used,because of the"curse of dimensionality".This paper propose... Slope reliability analysis considering inherent spatial variability(ISV)of soil properties is timeconsuming when response surface method(RSM)is used,because of the"curse of dimensionality".This paper proposes an effective method for identification of representative slip surfaces(RSSs)of slopes with spatially varied soils within the framework of limit equilibrium method(LEM),which utilizes an adaptive K-means clustering approach.Then,an improved slope reliability analysis based on the RSSs and RSM considering soil spatial variability,in perspective of computation efficiency,is established.The detailed implementation procedure of the proposed method is well documented,and the ability of the method in identifying RSSs and estimating reliability is investigated via three slope examples.Results show that the proposed method can automatically identify the RSSs of slope with only one evaluation of the conventional deterministic slope stability model.The RSSs are invariant with the statistics of soil properties,which allows parametric studies that are often required in slope reliability analysis to be efficiently achieved with ease.It is also found that the proposed method provides comparable values of factor of safety(FS)and probability of failure(Pf)of slopes with those obtained from direct analysis and lite rature. 展开更多
关键词 Slope reliability analysis Spatial variability representative slip surfaces(RSSs) Response surface method(RSM) Random field simulation
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Representative value of cross-fault in the northeastern margin of the Qinghai-Tibet block and case analysis of the 2016 Menyuan Ms6.4 earthquake 被引量:1
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作者 Ruisha Li Xi Zhang +2 位作者 Shouwen Gong Hongtao Tang Peng Jia 《Geodesy and Geodynamics》 2016年第4期268-274,共7页
The equation for determining cross-fault representative value is calculated based on hanging wall and foot wall reference level surfaces. The cross-fault data reliability are analyzed base on the stability of referenc... The equation for determining cross-fault representative value is calculated based on hanging wall and foot wall reference level surfaces. The cross-fault data reliability are analyzed base on the stability of reference datum and observation points, thereby facili- tating plotting of the representative value curves after removing interference. The spatial and temporal characteristics of fault deformation abnormalities before the 2016 Menyuan Ms6.4 earthquake, as well as the fault-movement characteristics reflected by representa- tive value, are summarized. The results show that many site trends had changed 1-3 years before the Menyuan Ms6.4 earthquake in the Qilian Fault, reflecting certain background abnormalities. The short-term abnormalities centrally had appeared in the 6 months to 1 year period before the earthquake near and in the neighborhood of the source region, demonstrating a significantly increased number of short-term abnormalities. Many sites near and in the neighborhood of the source region had strengthened inverse activities or had changed from positive to inverse activities in the most recent 2-3 years, which reflect stress-field enhancements or adjustment features. 展开更多
关键词 Northeastern margin of Qinghai- Tibet representative value of cross-faul t Menyuan Ms6.4 earthquake Fault activity Precursor Reference datum Stability
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Determining representative elementary volume size of in-situ expansive soils subjected to drying-wetting cycles through field test 被引量:3
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作者 CHENWei LI Guo-wei +3 位作者 HOU Yu-zhou WU Jian-tao YUAN Jun-ping Andrew Cudzo AMENUVOR 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第10期3246-3259,共14页
Cracks resulting from cyclic wetting and drying of expansive soils create discontinuities and anisotropy in the soil.The representative elementary volume(REV)defined by the continuous-media theory cannot be applied to... Cracks resulting from cyclic wetting and drying of expansive soils create discontinuities and anisotropy in the soil.The representative elementary volume(REV)defined by the continuous-media theory cannot be applied to cracked expansive soils that are considered discontinuous media.In this study,direct shear tests of three different scales(30 cm^(2),900 cm^(2),1963 cm^(2))and crack image analysis were carried out on undisturbed soil samples subjected to drying-wetting cycles in-situ.The REV size of expansive soil was investigated using the crack intensity factor(CIF)and soil cohesion.The results show that soil cohesion decreased with increasing sample area,and the development of secondary cracks further exacerbated the size effect of sample on cohesion of the soil.As shrinkage cracks developed,the REV size of the soil gradually increased and plateaued after 3−5 cycles.Under the same drying-wetting cycle conditions,the REV size determined using soil cohesion(REV-C)is 1.75 to 2.97 times the REV size determined using CIF(REV-CIF).Under the influence of shrinkage cracks,the average CIF is positively correlated with the REV size determined using different maximum permissible errors,with the coefficient of correlation greater than 0.9.A method for determining the REV-C based on crack image analysis is proposed,and the REV-C of expansive soil in the study area under different exposure times is given. 展开更多
关键词 representative elementary volume(REV) drying-wetting cycles expansive soil crack intensity factor(CIF) COHESION cracks
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Analysing the behavioural finance impact of ‘fake news’phenomena on financial markets:a representative agent model and empirical validation 被引量:1
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作者 Bryan Fong 《Financial Innovation》 2021年第1期1169-1198,共30页
This paper proposes an original behavioural finance representative agent model,to explain how fake news’empirical price impacts can persist in finance despite contradicting the efficient-market hypothesis.The model r... This paper proposes an original behavioural finance representative agent model,to explain how fake news’empirical price impacts can persist in finance despite contradicting the efficient-market hypothesis.The model reconciles empirically-observed price overreactions to fake news with empirically-observed price underreactions to real news,and predicts a novel secondary impact of fake news:that fake news in a security amplifies underreactions to subsequent real news for the security.Evaluating the model against a large-sample event study of the 2019 Chinese ADR Delisting Threat fake news and debunking event,this paper finds strong qualitative validation for its model’s dynamics and predictions. 展开更多
关键词 Behavioural finance Fake news representative agent model Event study BOOTSTRAPPING
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A sparse algorithm for adaptive pruning least square support vector regression machine based on global representative point ranking 被引量:2
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作者 HU Lei YI Guoxing HUANG Chao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2021年第1期151-162,共12页
Least square support vector regression(LSSVR)is a method for function approximation,whose solutions are typically non-sparse,which limits its application especially in some occasions of fast prediction.In this paper,a... Least square support vector regression(LSSVR)is a method for function approximation,whose solutions are typically non-sparse,which limits its application especially in some occasions of fast prediction.In this paper,a sparse algorithm for adaptive pruning LSSVR algorithm based on global representative point ranking(GRPR-AP-LSSVR)is proposed.At first,the global representative point ranking(GRPR)algorithm is given,and relevant data analysis experiment is implemented which depicts the importance ranking of data points.Furthermore,the pruning strategy of removing two samples in the decremental learning procedure is designed to accelerate the training speed and ensure the sparsity.The removed data points are utilized to test the temporary learning model which ensures the regression accuracy.Finally,the proposed algorithm is verified on artificial datasets and UCI regression datasets,and experimental results indicate that,compared with several benchmark algorithms,the GRPR-AP-LSSVR algorithm has excellent sparsity and prediction speed without impairing the generalization performance. 展开更多
关键词 least square support vector regression(LSSVR) global representative point ranking(GRPR) initial training dataset pruning strategy sparsity regression accuracy
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Relationship between Representatives of American Dream and Non-WASPs of America
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作者 陆妍 《海外英语》 2013年第18期187-188,共2页
American dream represents a wonderful wish of pursuit of better life, it attracts not only American, but also people all over the world to realize their dreams through hard-working. Focusing on people who have become ... American dream represents a wonderful wish of pursuit of better life, it attracts not only American, but also people all over the world to realize their dreams through hard-working. Focusing on people who have become representatives of American dream, we will find that most of them are Non-WASPS. 展开更多
关键词 representative AMERICAN DREAM Non-WASP
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A STUDY ON SAMPLING REPRESENTATIVENESS OF IAEA RM SD-M-2/TM MARINE SEDIMENT BY INAA
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作者 彭立新 田伟之 《Nuclear Science and Techniques》 SCIE CAS CSCD 1992年第1期8-12,共5页
The homogeneity of IAEA RM SD-M-2/TM Marine Sediment was tested by INAA. The sampling constants for 6 elements were determined.
关键词 Sampling representativeNESS Standard REFERENCE material
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COADJOINT ORBITS FOR THE CENTRAL EXTENSION OF Diff^+(S^1) AND THEIR REPRESENTATIVES
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作者 戴佳玲 Doug pickrell 《Acta Mathematica Scientia》 SCIE CSCD 2004年第2期185-205,共21页
According to Kirillov's idea, the irreducible unitary representations of a Lie group G roughly correspond to the coadjoint orbits (?).In the forward direction one applies the methods of geometric quantization to p... According to Kirillov's idea, the irreducible unitary representations of a Lie group G roughly correspond to the coadjoint orbits (?).In the forward direction one applies the methods of geometric quantization to produce a representation, and in the reverse direction one computes a transform of the character of a representation, to obtain a coadjoint orbit. The method of orbits in the representations of Lie groups suggests the detailed study of coadjoint orbits of a Lie group G in the space (?)~* dual to the Lie algebra (?) of G. In this paper, two primary goals are achieved: one is to completely classify the smooth coadjoint orbits of Virasoro group for nonzero central charge c; the other is to find representatives for coadjoint orbits. These questions have been considered previously by Segal, Kirillov, and Witten, but their results are not quite complete. To accomplish this, the authors start by describing the coadjoint action of D-the Lie group of all orientation preserving diffeomorphisms on the circle S^1, and its central extension (?), then the authors will give a complete classification of smooth coadjoint orbits. In fact, they can be parameterized by a subspace Of conjugacy classes of (?)(1,1). Finally, the authors will show how to find representatives f coadjoint orbits by analyzing the vector fields stabilizing the orbits, and describe the amazing connection between the characteristic (trace) of conjugacy classes of (?)(1, 1) and that of vector fields stabilizing orbits. 展开更多
关键词 Coadjoint representations coadjoint orbits STABILIZERS vector fields representatives
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On the Angular Distribution of the Representative Points of Bases of Human Protein Coding Sequences
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作者 Zhou Guoxiang Wang Aikun He Wenchen(Mathematics and Physics Department,Hebei University of Technology, 300130, Tianjin, China) 《河北工业大学学报》 CAS 1997年第A01期1-4,共4页
A novel diagrammtic method is proposed to show the angular distribution of bases of human protein sequences. Using this method, the distribution sphere[1-4] is divided into four regions with same volume. The picture i... A novel diagrammtic method is proposed to show the angular distribution of bases of human protein sequences. Using this method, the distribution sphere[1-4] is divided into four regions with same volume. The picture is clearer and more intuitive than that in [1] .A rule on the angular distribution of the representative points of bases of protein sequences is given. Besides, in 300 representative pointS of human protein sequence samples we find that there are three (not only one) points outside the sphere. 展开更多
关键词 ANGULAR DISTRIBUTION representative point of BASES of protein CODING sequence/ DISTRIBUTION SPHERE
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Minimum Representative Size in Comparing Research Performance of Universities:the Case of Medicine Faculties in Romania
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作者 Xiaoling Liu Mihai Paunescu +1 位作者 Viorel Proteasa Jinshan Wu 《Journal of Data and Information Science》 CSCD 2018年第3期32-42,共11页
Purpose: The main goal of this study is to provide reliable comparison of performance in higher education. In this respect, we use scientometric measures associated with faculties of medicine in the six health studie... Purpose: The main goal of this study is to provide reliable comparison of performance in higher education. In this respect, we use scientometric measures associated with faculties of medicine in the six health studies universities in Romania.Design/methodology/approach: The method to estimate the minimum necessary size, proposed in in Shen et al.(2017), is applied in this article. We collected data from the Scopus data-base for the academics of the departments of medicine within the six health studies universities in Romania during the 2009 to 2014. And two kind of statistic treatments based on that method are implemented, pair-wise comparison and one-to-the-rest comparison. All the results of these comparisons are shown.Findings: According to the results: We deem that Cluj and Tg. Mure? have the superior and inferior performance respectively, since their reasonably small value of the minimum representative size, in either of the kinds of comparison, whichever indexes of citations, h-index, or g-index is used. we can not reliably distinguish differences among the rest of the faculties, since the quite large value of their minimum representative size.Research limitations: There is only six faculties of medicine in health studies universities in Romania are analyzed.Practical implications: Our methods of comparison play an important role in ranking data sets associated with different collective units, such as faculties, universities, institutions, based on some aggregate scores like mean and totality. Originality/value: We applied the minimum representative size to a new emprical context- that of the departments of medicine in the health studies universities in Romania. 展开更多
关键词 Research evaluation Minimum representative size Bootstrap sampling Medicine departments
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Projection of Future Changes in Elephant Population in Amboseli under Representative Concentration Pathways
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作者 Mildred M. Aduma Mohamed Y. Said +2 位作者 Gilbert Ouma Gordon Wayumba Lucy W. Njino 《American Journal of Climate Change》 2018年第4期649-679,共31页
Within savanna environments, movements of elephant are influenced by changes in climate especially seasonal rainfall. In this study, we investigated the possible changes in elephant population based on projected rainf... Within savanna environments, movements of elephant are influenced by changes in climate especially seasonal rainfall. In this study, we investigated the possible changes in elephant population based on projected rainfall changes using regional climate models (RCM) and Representative Concentration Pathways (RCPs). The relationship between elephant and rainfall was modelled against annual, wet season, dry season rainfall based on various time lags. Future relation between elephant and rainfall was projected based on three RCPs;2.6, 4.5 and 8.5. There was a strong linear relationship between elephant and October-November-December (OND) rains with time lag of 13 years (Y = &#8722;4016.43 + 19.11x, r2 = 0.459, P = 0.006). The rainfall trends for RCP 2.6 and 4.5 showed a slight increase in annual rainfall for the period 2006-2100 but driven by OND increases. Rainfall increase for RCP 8.5 was significant and was driven by increase in both March-April-May (MAM) and OND. These rainfall dynamics had influence on the projected elephant population in the Amboseli ecosystem. For RCP 2.6 and 4.5 the elephant population increase was 2455 and 2814 respectively. RCP 8.5 elephant population doubled to an average of 3348 elephants. In all the RCPs there are seasonal and yearly variations and absolute number varies from the average. The range of variation is small in RCPs 2.6 and 4.5 compared to RCP 8.5. Evidently, elephant population will increase based on projected rainfall projections surpassing park capacity. It therefore, requires that the Park authority put in place measures that could contain these numbers including opening of blocked wildlife corridors, maintain the cross border movement of Amboseli elephant with Tanzania in that case ensure there is no poaching. Lastly, work with local communities so that they can benefit from tourism through setting up conservancies through which they could minimize the human elephant conflicts based on the projected elephant population. 展开更多
关键词 representative CONCENTRATION PATHWAYS 2.6 4.5 and 8.5 RAINFALL Variability POPULATION Dynamics
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District Partisan Homogeneity, Communications, and the Electoral Motive: An Analysis of the Facebook Posts of Members of the U.S. House of Representatives
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作者 Scot Schraufnagel Quan Li Adam Schuster 《Social Networking》 2017年第2期148-163,共16页
The research examines the way in which members of the U.S. House of Representative represent themselves on the social network site Facebook. Each member’s activity is observed on seven different occasions and the fre... The research examines the way in which members of the U.S. House of Representative represent themselves on the social network site Facebook. Each member’s activity is observed on seven different occasions and the frequency and substantive character of posts made during the second half of 2013 are established. The focus is on position-taking posts versus posts which mention the district the member serves in. Our expectation is that members from electorally safe districts will be more likely to advertise their policy positions while members from marginal districts will be more inclined to advertise their district connections. We control for minority party status, gender, and ideological extremism among other concerns and learn electoral safety is a good predictor of both “position-taking” and “district mentions”. Consistent with an electoral motive, we also find members from the minority party less likely to take positions on the issues of the day and more likely to mention the district they serve in. 展开更多
关键词 U.S. House of representatives FACEBOOK POSTS Electoral Motives CREDIT Claiming
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Representative heights for assessing whole-tree values of cell-type proportions in Eucalyptus camaldulensis and E. globulus
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作者 Jyunichi Ohshima Kazuya Iizuka +2 位作者 Futoshi Ishiguri Shinso Yokota Toshihiro Ona 《Journal of Forestry Research》 SCIE CAS CSCD 2020年第3期885-900,共16页
Eucalyptus camaldulensis Dehnh. and E. globulus Labill. are economically important species for wood and pulpwood materials. Representative heights for assessing whole-tree values of cell-type proportions(vessels, fibe... Eucalyptus camaldulensis Dehnh. and E. globulus Labill. are economically important species for wood and pulpwood materials. Representative heights for assessing whole-tree values of cell-type proportions(vessels, fibers, ray and axial parenchyma percentages) using increment cores were examined by analysis of within-tree variations. Pattern differences were evaluated between trees and species in both radial and axial directions by statistical data analysis(Moses test). In E. camaldulensis,within-tree variation of vessel percentage was generally higher in the upper and outer regions of the trunk. In contrast, E. globulus within-tree variation was unclear. In both species, although no clear pattern of fiber percentages was observed, within-tree variations of ray and axial parenchyma levels were higher in the lower and inner regions.Significant differences in patterns were observed in the axial variation between species for vessel percentages and in the radial variation between trees of E. camaldulensis for ray parenchyma percentages. The representative heights for assessing whole-tree cell-type proportions were 0.8 mabove the ground for E. camaldulensis and 2.8 m for E.globulus, regardless of differences in tree height and pattern of within-tree variation of cell-type proportions. 展开更多
关键词 Eucalyptus CELL-TYPE proportion Within-tree variation representative height Quality breeding
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Representativeness of suspected measles cases reported in a southern district of Nigeria
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作者 Akinola A Fatiregun Chuks C Odega 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2013年第2期153-156,共4页
Objective:To compare the characteristics of suspected measles cases at the health facilities and to determine the representativeness of the data.Methods:We visited 25 hospitals in the Aniocha Local Government Area(LGA... Objective:To compare the characteristics of suspected measles cases at the health facilities and to determine the representativeness of the data.Methods:We visited 25 hospitals in the Aniocha Local Government Area(LGA) of Delta State,Nigeria,from which information on reportable diseases was collected.In particular,the suspected measles cases in their registries between January 1,2007,and June 30,2008,were reviewed.We compared the characteristics,including age,sex,location,and month of reporting,of the suspected cases with the LGA surveillance records.Results:In the LGA records,10%cases involved individuals older than 14 years, compared with 20%in the same age group in the health facility records.Based on geographic location,53%of the measles cases among the hospital records came from a single location,in contrast to only 30%of the cases among the LGA records.An analysis considering time revealed that 30%of the cases in the LGA records occurred in August 2007,whereas 20%of hospital cases were reported in February and May 2008 combined.Conclusions:The two record types differed considerably in all of the characteristics used in this comparison. 展开更多
关键词 representativeness of data Suspected measles Surveillance evaluation NIGERIA
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Revealing the Pressure-Induced Softening/Weakening Mechanism in Representative Covalent Materials
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作者 Tengfei Xu Shihao Zhang +2 位作者 Dominik Legut Stan Veprek Ruifeng Zhang 《Chinese Physics Letters》 SCIE CAS CSCD 2021年第5期51-59,共9页
Diamond, cubic boron nitride(c-BN), silicon(Si), and germanium(Ge), as examples of typical strong covalent materials, have been extensively investigated in recent decades, owing to their fundamental importance in mate... Diamond, cubic boron nitride(c-BN), silicon(Si), and germanium(Ge), as examples of typical strong covalent materials, have been extensively investigated in recent decades, owing to their fundamental importance in material science and industry. However, an in-depth analysis of the character of these materials' mechanical behaviors under harsh service environments, such as high pressure, has yet to be conducted. Based on several mechanical criteria, the effect of pressure on the mechanical properties of these materials is comprehensively investigated.It is demonstrated that, with respect to their intrinsic brittleness/ductile nature, all these materials exhibit ubiquitous pressure-enhanced ductility. By analyzing the strength variation under uniform deformation, together with the corresponding electronic structures, we reveal for the first time that the pressure-induced mechanical softening/weakening exhibits distinct characteristics between diamond and c-BN, owing to the differences in their abnormal charge-depletion evolution under applied strain, whereas a monotonous weakening phenomenon is observed in Si and Ge. Further investigation into dislocation-mediated plastic resistance indicates that the pressure-induced shuffle-set plane softening in diamond(c-BN), and weakening in Si(Ge), can be attributed to the reduction of antibonding states below the Fermi level, and an enhanced metallization, corresponding to the weakening of the bonds around the slipped plane with increasing pressure, respectively. These findings not only reveal the physical mechanism of pressure-induced softening/weakening in covalent materials, but also highlights the necessity of exploring strain-tunable electronic structures to emphasize the mechanical response in such covalent materials. 展开更多
关键词 red service Revealing the Pressure-Induced Softening/Weakening Mechanism in representative Covalent Materials
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North American Association Put Manufacturers and Representatives Together
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作者 Joseph W.Miller 《China's Foreign Trade》 2002年第5期57-58,共2页
For more than half a centurymanufacturers in search of independentrepresentatives to sell their products innew markets and to establishrelationships with prospective customershave relied upon the services of theManufa... For more than half a centurymanufacturers in search of independentrepresentatives to sell their products innew markets and to establishrelationships with prospective customershave relied upon the services of theManufacturers’ Agents NationalAssociation (MANA). 展开更多
关键词 AS North American Association Put Manufacturers and representatives Together MORE
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