1995-2006年重庆市经济增长与环境污染关系析论     

李琳  朱金山  高润霞  黄安寿 《安顺师范高等专科学校学报》2008,10(6):91-93

文章以1995--2006年重庆市经济发展的主要指标和环境污染物排放量的统计资料为依据,采用环境库兹涅茨曲线模型,分析了10余年来重庆市人均GDP与工业污染物排放量的相关关系,同时与京、津、沪及兰州等代表城市的人均GDP工业污染物排放量的相关关系进行了对比。  相似文献   

二阶变系数偏微分方程的分类     

麦麦提明·阿不都克力木 《喀什师范学院学报》2006,27(3):6-7

介绍了两个自变量的二阶偏微分方程分类,然后给出了多个自变量的变系数偏微分方程的分类.  相似文献   

Latent growth curve modeling in exercise science     

Christine E. Pacewicz  Nicholas D. Myers 《Measurement in physical education and exercise science》2021,25(1):53-65

ABSTRACT

Longitudinal measurement enables the examination of behavioral or psychological change. One approach to examining longitudinal measurements is the use of latent growth curve modeling (LGCM). This approach affords the assessment of inter- and intraindividual change. Yet, this approach likely is underused in exercise science. The purpose of the current study was to describe and demonstrate the use of LGCM to examine change using multiple measurements in the field of exercise science. We first provide a substantive review of LGCM. We highlight the use of unconditional models to find an appropriate model of change, how and why to utilize autoregressions, and how to examine predictors of change in conditional models. We then provide an illustration of the approach using data from the Michigan State Motor Performance Study. In the conclusion, we discuss the advantages and limitations of the approach and suggest future directions when assessing longitudinal data in exercise science.  相似文献   

教育均衡问题的客观性与主观性     

温丽萍 《重庆第二师范学院学报》2012,25(5):119-122

用库兹涅茨曲线及相对剥夺理论分析与解读教育均衡问题所呈现的复杂现象,并提出教育均衡问题不仅是一个教育领域中的问题,也是一个复杂的社会问题,整个社会的公平与平等是教育均衡与公平的根本。  相似文献   

一维线性系统的无阻尼受迫振动研究     

黄焱  何松林  林文慧 《昆明师范高等专科学校学报》2012,(3):97-99

在功率谱分析的基础上,用尝试法得出了一维线性系统仅受简谐强迫力作用时的振动微分方程的解,并据此对无阻尼受迫振动的性质进行了讨论,得到一些有益的结果.  相似文献   

Rowing     

Bruce Elliott  Andrew Lyttle  Olivia Birkett 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):123-134

The purpose of this study was to compare rowing technique on the dynamic RowPerfect ergometer with a single scull. Eight national‐level rowers performed on both the RowPerfect ergometer and in a single scull over 500 m, at rates of 24, 26, and 28 strokes/minute. Blade force and oar angle (on‐water) and handle force and stroke length (on the ergometer) were measured. Both force and stroke angle/length were normalised from 0 to 100 (where 100 was the peak value). Body positions of the subjects at both the catch and finish of each of these rowing strokes were also compared for each stroke rate. The coefficient of multiple determination (CMD) was used to measure the consistency of force curves over a sample of five sequential strokes for each rower. Cross‐correlations were performed between the left‐ and right‐ side on‐water sculling force curves and a mean of these values with the ergometer curve for each rower. Stroke angle/length, which did not vary with rate, was similar for both forms of rowing. The CMDs showed a high consistency across the normalised strokes of each subject (≈0.98). Cross‐correlation values of 0.91, 0.92, and 0.93 were recorded between the force curves from the ergometer and on‐water trials for stroke rates of 24, 26, and 28 strokes/minute, respectively. The mean trunk, thigh and lower leg angles at the catch and finish of the stroke were also similar across the stroke rates as determined by t‐tests. Results indicate that technique used on the RowPerfect ergometer was similar to that for on‐water sculling, thus validating its use in off‐water training.  相似文献   

The Relationships Among Isokinetic Endurance,Initial Strength Level,and Fiber Type     

Priscilla M. Clarkson  James Johnson  Dennis Dextradeur  William Leszczynski  Jackson Wai  Anthony Melchionda 《Research quarterly for exercise and sport》2013,84(1):15-19

Abstract

Knee extension isokinetic peak torque was assessed at angular velocities of 0, 30, 180, and 240[ddot]/sec, and isokinetic endurance was assessed by 50 consecutive contractions at 180[ddot]/sec in eight college age men. Also, muscle fiber type of the vastus lateralis was determined and related to isokinetic strength and fatigability. To determine the influence of initial strength on isokinetic endurance the 50 serial isokinetic contractions were assessed after subjects performed two bicycle exercise regimens designed to affect initial strength levels. Neither isokinetic peak torques (made relative to MVC or per Kg of body weight) nor the amount of strength loss over the 50 contractions correlated with fiber type. The peak torques at 180[ddot]/sec at the start of the 50 contractions differed over the three conditions (unfatigued and after the two bicycle exercise regimens), however, the amount of of strength loss over the 50 trials was similar for the three conditions. Also, the patterns of the three isokinetic fatigue curves were remarkably similar. Thus, the initial strength level across the treatments did not affect the rate of fatigue. However, when the treatment conditions were examined separately, the amount of strength loss over the 50 trials correlated significantly with initial strength. Thus, factors other than, or in addition to, fiber type and initial strength level must influence the rate of isokinetic fatigue.  相似文献   

各国参与全球价值链的环境库兹涅茨效应——基于跨国面板数据     

赖晓瑾  唐一丁  祝树金 《资源科学》2022,44(8):1630-1644

随着经济全球化概念越来越深刻地体现在国际分工专业化和经济增长模式中,全球价值链（GVC）的深化将如何影响环境这一问题引发了越来越多的思考。本文立足于GVC的视角,利用1995—2018年64个国家的面板数据,依托环境库兹涅茨曲线（EKC）理论体系,探究了参与GVC对于环境污染和经济增长关联性的影响,分析各国参与GVC是否会影响EKC的“拐点”。研究结论表明：①GVC参与度的提高将显著延后EKC“拐点”的到来,这一“延后”主要源于后向GVC分工的驱动,而前向GVC分工的提升将有助于EKC“拐点”的提前。②参与GVC对EKC“拐点”的影响存在国家异质性,环境规制严格的国家参与GVC将助其更早迎来“拐点”,实现经济发展意义上的碳达峰;而规制宽松的国家参与GVC则可能沦为“污染天堂”。③GVC参与度对EKC“拐点”的影响存在行业异质性,其中技术密集型行业前向GVC参与度的提升将有效推动EKC“拐点”提前到来。④GVC参与度与CO₂之间存在倒U型的非线性关系。本文的发现丰富了全球价值链在经济和环境效应方面的实证应用,为协调经济高质量发展与生态环境约束提供了新思路。  相似文献   

Dropout and Downward Mobility in the Educational Career: An Event-History Anaylsis of Ethnic Schooling Differences in the Netherlands     

Matthijs Kalmijn  Gerbert Kraaykamp 《Educational Research and Evaluation》2013,19(3):265-287

While many aspects of educational careers have been examined ill the literature on ethnic minorities, such as truancy, turnover and grades, downward mobility has rarely been studied. Using data on more than 10,000 students who entered secondary school in The Netherlands in 1989, we develop an event-history model for secondary school careers and we use this model to analyse the determinants of dropout and downward mobility simultaneously. Our findings show that students from Mediterranean and Caribbean immigrant families are about 3 times as likely to drop out from secondary school without a degree compared to Dutch children. They are also more likely to be downwardly mobile during their secondary school career, but this differential is weaker Compositional differences with respect to individual ability and parental resources explain a large part of these differences. When holding constant parental resources and individual ability, ethnic students are less likely to experience downward mobility than Dutch students. In other words, when there is failure in the school career Dutch children are more likely to follow the route of downward mobility whereas children from ethnic minorities are more likely to drop out altogether. The multitrack nature of the Dutch educational system thus may have a negative impact on ethnic inequality.  相似文献   

六安市经济增长与环境污染关系的研究——基于环境Kuznets理论的实证分析     

黄润  赵瑞瑞 《六安师专学报》2013,(5):15-19

根据六安市2001～2010年数据,选取工业“三废”、化学需氧量（COD）以及二氧化硫（SO2）排放量为环境指标,人均GDP为经济指标,借助SPSS和EXCEL软件系统,对人均GDP与污染物排放量之间的关系进行了分析.结果表明,工业废水排放量与人均GDP的曲线呈倒“U”型和“U”型相结合的曲线型;工业废气排放量及化学需氧量与人均GDP的曲线呈倒“U”型;工业固体废弃物排放量与人均GDP的曲线无转折点,呈曲线上升型;二氧化硫排放量与人均GDP则呈现出正“N”型.固体废弃物的处理是目前六安市环境朝着良性方向发展的关键所在.  相似文献