车辆与路面相互作用下的5轴重型卡车非线性动态分析

基于车辆悬挂系统和轮胎的几何非线性特性分析,建立了一重型卡车三维非线性动态模型,采用动态车轮载荷的影响因子即动载荷应力因子、最大和最小垂直动载系数,对路面随机不平度与重型车辆之间的动态相互作用进行了评价.采用Matlab/Simulink软件对建立的非线性动态系统模型及影响因子进行仿真计算.分析了不同路面条件对车辆行驶...     

Relations between informational sources,self-efficacy and academic achievement: a developmental approach

As a cognitive-motivational construct, self-efficacy has been researched extensively and has involved two important lines of inquiries, namely the impact of sources of information on self-efficacy and the predictive effect of self-efficacy on learning outcomes. We proposed and tested the relations between the four major sources of information (enactive performance accomplishments, vicarious experiences, verbal persuasion and emotional and physiological states), self-efficacy and academic achievement for mathematics and science within one conceptual model. Our model was tested with the conjunctive use of longitudinal data and latent growth curve modelling (LGM) procedures. Two hundred and fifty-two (110 girls, 142 boys) upper elementary school children from three government schools participated in this longitudinal study. Likert-scale inventories were administered over four occasions within a one-year period. We measured the four sources of information at T ₁, whereas self-efficacy for mathematics and science was measured at T ₂–T ₄, and academic achievement was measured at T ₄ only. SPSS AMOS v18 was used to test a number of a priori multivariate growth curve models. LGM analyses provided moderate evidence in support of our conceptual model, noting different patterns of trajectories for both mathematics and science.     

Waiting to decide helps in the face of probabilistic uncertainty but not delay uncertainty

A first-person shooter video game was adapted for the study of causal decision making within dynamic environments. Participants chose which of three potential targets in each of 21 groups was producing distal explosions. The source of the explosion effect varied in the delay between the firing of its weapon and its effect (0.0, 0.5, 1.0, and 2.0 s), the probability that the weapon caused the effect (50%, 75%, and 100%), and the occurrence of auditory events that filled the delay. In Experiment 1, participants’ choice accuracy was highest with short delays but was not affected by probability; participants often compensated for lower probability by increasing their latencies, and thus the number of outcomes sampled. In Experiment 2, a broad range of delays (0–2 s) and probabilities (20%–100%) were randomly sampled for each cause; the results largely replicated those of the prior experiment. The experiments demonstrate people’s ability to successfully modulate their environmental sampling in the face of uncertainty due to lower cause–effect probabilities, but not in the presence of longer cause–effect delays.     

How academics manage individual differences to team teach in higher education: a sociocultural activity theory perspective

Higher Education - In the higher education (HE) landscape worldwide, team teaching has become increasingly common. The growing prevalence of team teaching in HE has mainly been driven by the...     

Survey reveals slow strides in promoting adolescent reproductive health in Vietnam

This article presents the findings of a survey evaluating the adolescent reproductive health program by the Vietnamese Government. Conducted by the Population Research Consultants, survey findings revealed several setbacks of the adolescent reproductive health program; these included the following: 1) adolescents favor radio, television and newspapers as sources of reproductive health (RH) information; 2) adolescents have no knowledge of pregnancy, sexually transmitted diseases, and HIV/AIDS prevention; 3) the demand for RH information varies according to the sociodemographic characteristics of respondents; 4) while the majority of adolescents do not favor premarital sex and premarital pregnancy, their choice is to keep and deliver the baby in case of a premarital pregnancy; 5) adolescents give a poor rating to the quality of RH/family planning services at the centers; 6) adolescents need to further understand RH but not knowing its meaning, they cannot tell what type of information they require; 6) adolescents have poor knowledge of adolescent reproductive health; 7) friendship and love are often discussed among adolescents, but sexuality rarely is; and 8) adolescents have poor knowledge of RH and poor interest in RH/family planning service facilities.     

Empirical model and analysis of mastery and performance‐approach goals: a developmental approach

This study used latent growth modelling (LGM) to explore the developmental course and longitudinal relationships between achievement goals (mastery and performance‐approach) and academic performance over a three‐year period (four time‐points of data collection). Three hundred and fifty‐two university students (152 women, 200 men) who first enrolled in 2006 took part in this study. Likert‐scale inventories were used to elicit relevant data from students. Academic performance was collated from students' course and final exam marks in two different undergraduate courses. LISREL 8.72 and SPSS 17 were used to test and evaluate the conceptual model proposed. Causal modelling analyses indicated the temporally displaced effects of mastery and performance‐approach goals on academic performance. The results indicated that individuals' mastery goals increased over time, whereas there was no increase in growth change with performance‐approach goals. Causal modelling also indicated: (1) performance‐approach goals → academic performance → mastery goals relationship and (2) mastery goals → academic performance → mastery goals relationship. Finally, the use of LGM provided a clearer perspective concerning the developmental trajectories of mastery goals over time.