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1.
从动脉血管系统的血管壁、血液以及动脉血管周围组织的生理物性出发,建立了脉搏波波形特征的数学表达式,从物理学以及数学的角度在理论上分析了脉搏波波形的特征随生理参数的变化情况。改变血管的杨氏模量,血液的粘度以及血管半径参数后发现所得的脉搏图与能较好的反映生理信息,本文所得到的结果为脉搏波的波形特征的进一步研究奠定了理论基础,也有助于临床上利用脉搏波的传播特性来分析和诊断相关的疾病。  相似文献   
2.
Children's target experiences (as recipients of prosocial peer acts and victims of peer aggression) were investigated for their concurrent and longitudinal associations with prosocial and aggressive behavior. Forty‐four children (initially 22–40 months) were observed in naturalistic interactions with peers during a two‐month period for each of three consecutive years. Results revealed no consistency over time in children's experiences as targets for aggressive or prosocial peer acts, although there was some indication that altruistic target experiences may be stable from the end of the preschool period. Early behavior appeared to affect the way children were later treated by peers, but no support was found for the idea that early target experiences influence later behavior. Prosocial behavior was concurrently and longitudinally associated with prosocial target experiences. Aggressive behavior reduced the likelihood of children being targets of prosocial peer behavior and, over time, also of their being targets of peers’ aggression.  相似文献   
3.
In this article, we propose an outlier detection approach in a multiple regression model using the properties of a difference-based variance estimator. This type of a difference-based variance estimator was originally used to estimate error variance in a non parametric regression model without estimating a non parametric function. This article first employed a difference-based error variance estimator to study the outlier detection problem in a multiple regression model. Our approach uses the leave-one-out type method based on difference-based error variance. The existing outlier detection approaches using the leave-one-out approach are highly affected by other outliers, while ours is not because our approach does not use the regression coefficient estimator. We compared our approach with several existing methods using a simulation study, suggesting the outperformance of our approach. The advantages of our approach are demonstrated using a real data application. Our approach can be extended to the non parametric regression model for outlier detection.  相似文献   
4.
In this paper we explore statistical properties of some difference-based approaches to estimate an error variance for small sample based on nonparametric regression which satisfies Lipschitz condition. Our study is motivated by Tong and Wang (2005), who estimated error variance using a least squares approach. They considered the error variance as the intercept in a simple linear regression which was obtained from the expectation of their lag-k Rice estimator. Their variance estimators are highly dependent on the setting of a regressor and weight of their simple linear regression. Although this regressor and weight can be varied based on the characteristic of an unknown nonparametric mean function, Tong and Wang (2005) have used a fixed regressor and weight in a large sample and gave no indication of how to determine the regressor and the weight. In this paper, we propose a new approach via local quadratic approximation to determine this regressor and weight. Using our proposed regressor and weight, we estimate the error variance as the intercept of simple linear regression using both ordinary least squares and weighted least squares. Our approach applies to both small and large samples, while most existing difference-based methods are appropriate solely for large samples. We compare the performance of our approach with other existing approaches using extensive simulation study. The advantage of our approach is demonstrated using a real data set.  相似文献   
5.
鸦片战争以后,中国社会逐步由封建社会向半殖民地半封建社会转变。广东的社会变迁比起中国其它地方特别是内地更为迅速、显著。这种社会状况对宗教产生了相当大的冲击和影响,使得近代广东乃至全国的宗教呈现出与古代社会不同的状况,表现出新的特点与趋势。  相似文献   
6.
This paper analyses recent experiences at the School of Social Work, Lund University, the first in Sweden to use an innovative pedagogical approach for integrating social service users with social work students in the classroom (an EU-funded project). The concept of gift exchange was used to make sense of the approach. Gift exchange is based on the norm of reciprocity and the principles of gift economy—to give, to receive and to return. As one of the most significant integrative relations, this exchange of gifts and courtesies serves the purpose of keeping balance in the system. The focus in this project was on the relationship between two groups of students: service user students—that is, social service users in the role of students on the course—and social work students. The experience of undertaking this project raised many questions, such as what promotes and what hinders mutual learning between two parties in the classroom. Findings show the relevance of such concepts as the gift economy and the importance of reciprocity in teaching contexts. They played an important role in the process of creating a positive learning climate and understanding the integration of social relations between the two groups.  相似文献   
7.
Abstract

In this paper, we propose an outlier-detection approach that uses the properties of an intercept estimator in a difference-based regression model (DBRM) that we first introduce. This DBRM uses multiple linear regression, and invented it to detect outliers in a multiple linear regression. Our outlier-detection approach uses only the intercept; it does not require estimates for the other parameters in the DBRM. In this paper, we first employed a difference-based intercept estimator to study the outlier-detection problem in a multiple regression model. We compared our approach with several existing methods in a simulation study and the results suggest that our approach outperformed the others. We also demonstrated the advantage of our approach using a real data application. Our approach can extend to nonparametric regression models for outliers detection.  相似文献   
8.
The aim of this study was to investigate walking and health among woman age 75 yr or older, in the associations between the highest step up performed without support by an individual and balance, walking, and health among women age 75+. Records of the highest step, balance, walking, and health were made for 307 women age 75-93 yr living in the community. Eighty percent managed to climb steps higher than 20 cm. There was a statistically significant negative relationship between age and stair-climbing capacity. The highest steps registered were significantly and independently associated with a short time on the timed up-and-go test, long functional reach, low body weight, lack of perceived difficulty walking outdoors, low number of "missteps" when walking in a figure of 8, longer time in one-leg stance, ability to carry out tandem stance, no walking aids outdoors, and not being afraid of falling. These variables together explained 67% of the variance in the step-height score.  相似文献   
9.
10.
本文对乒乓球运动的审美娱乐性进行了研究和分析,认为在全民健身的运动中,乒乓球运动因其在国人心目中的特殊地位和文化及审美上的影响力,是应大力普及的体育运动项目。  相似文献   
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