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61.
A Monte-Carlo simulation was conducted to assess the extent that a correlation estimate can be inflated when an average-based measure is used in a commonly employed correlational design. The results from the simulation reveal that the inflation of the correlation estimate can be substantial, up to 76%. Additionally, data was re-analyzed from two previously published studies to determine the extent that the correlation estimate was inflated due to the use of an averaged based measure. The re-analyses reveal that correlation estimates had been inflated by just over 50% in both studies. Although these findings are disconcerting, we are somewhat comforted by the fact that there is a simple and easy analysis that can be employed to prevent the inflation of the correlation estimate that we have simulated and observed.  相似文献   
62.
Abstract

This 1-year longitudinal study examined the bidirectional mediating role of loneliness in the association between shyness and generalized pathological Internet use (GPIU) in a sample of 291 Chinese university students (143 men, mean age =?19.07?years). A fully cross-lagged panel design was used in which shyness, loneliness, and GPIU were assessed at 3 time points separated by 6-month intervals (named T1, T2, and T3). The results indicated that relationships among shyness, loneliness, and GPIU were dynamic and bidirectional. Specifically, T1 shyness positively predicted increased T2 loneliness, T2 shyness positively predicted increased T3 loneliness, and T2 loneliness positively predicted increased T3 shyness. Additionally, T1 GPIU positively predicted increased T2 loneliness, T2 GPIU positively predicted increased T3 loneliness, and T2 loneliness positively predicted increased T3 GPIU. Loneliness was found to play a bidirectional mediating role in the association between shyness and GPIU. Specifically, T1 shyness and T3 GPIU were mediated through increased loneliness at T2, and T1 GPIU and T3 shyness were mediated through increased loneliness at T2. Furthermore, relationships among shyness, loneliness, and GPIU were the same across the 2 groups, with the strength of relationships being stronger for men.  相似文献   
63.
Growth curve models with different types of distributions of random effects and of intraindividual measurement errors for robust analysis are compared. After demonstrating the influence of distribution specification on parameter estimation, 3 methods for diagnosing the distributions for both random effects and intraindividual measurement errors are proposed and evaluated. The methods include (a) distribution checking based on individual growth curve analysis; (b) distribution comparison based on Deviance Information Criterion, and (c) post hoc checking of degrees of freedom estimates for t distributions. The performance of the methods is compared through simulation studies. When the sample size is reasonably large, the method of post hoc checking of degrees of freedom estimates works best. A web interface is developed to ease the use of the 3 methods. Application of the 3 methods is illustrated through growth curve analysis of mathematical ability development using data on the Peabody Individual Achievement Test Mathematics assessment from the National Longitudinal Survey of Youth 1997 Cohort (Bureau of Labor Statistics, U.S. Department of Labor, 2005).  相似文献   
64.
A key challenge in the fabrication of superhard nanocomposite films is how to control the distribution of grain sizes in these materials. High-resolution transmission electron microscopy has been used to measure nanograin-size distributions in the Ti–B–N films with various B contents. The results show that the mean grain size decreases with increase of B content and the grain-size distribution conforms to a log-normal function when the hardness approaches a maximum value. The transition from normal to log-normal distributions can be determined by analysis in terms of a minimum information criterion. The origin of a log-normal size distribution probably results from heterogeneity arising from a diffusion-drift process.  相似文献   
65.
We propose a phase-field model for modeling microstructure evolution during deformation twinning. The order parameters are proportional to the shear strains defined in terms of twin plane orientations and twinning directions. Using a face-centered cubic Al as an example, the deformation energy as a function of shear strain is obtained using first-principle calculations. The gradient energy coefficients are fitted to the twin boundary energies along the twinning planes and to the dislocation core energies along the directions that are perpendicular to the twinning planes. The elastic strain energy of a twinned structure is included using the Khachaturyan's elastic theory. We simulated the twinning process and microstructure evolution under a number of fixed deformations and predicted the twinning plane orientations and microstructures.  相似文献   
66.
A numerical model is proposed to simulate fracture induced by the coalescence of numerous microcracks, in which the condition for coalescence between two randomly nucleated microcracks is determined in terms of a load-sharing principle. The results of the simulation show that, as the number density of nucleated microcracks increases, stochastic coalescence first occurs followed by a small fluctuation, and finally a newly nucleated microcrack triggers a cascade coalescence of microcracks resulting in catastrophic failure. The fracture profiles exhibit self-affine fractal characteristics with a universal roughness exponent, but the critical damage threshold is sensitive to details of the model. The spatiotemporal distribution of nucleated microcracks in the vicinity of critical failure follows a power-law behaviour, which implies that the microcrack system may evolve to a critical state.  相似文献   
67.
This article applies a two-process “neural autopilot” model to field data. The autopilot model hypothesizes that habitual choice occurs when the reward from a behavior has low numerical “doubt” (i.e., reward prediction errors are small). The model toggles between repeating a previous choice (habit) when doubt is low and making a goal-directed choice when doubt is high. The model has ingredients established in animal learning and cognitive neuroscience and is simple enough to make nonobvious predictions. In two empirical applications, we fit the model to field data on purchases of canned tuna and posting on the Chinese social media site Weibo. This style of modeling is called “structural” because there is a theoretical model of how different variables influence choices by agents (the “structure”), which tightly restricts how hidden variables lead to observed choices. There is empirical support for the model, more strongly for tuna purchases than for Weibo posting, relative to a baseline “reduced-form” model in which current choices are correlated with past choices without a mechanistic (structural) explanation. An interesting set of predictions can also be derived about how consumers react to different kinds of changes in prices and qualities of goods (this is called “counterfactual analysis”).  相似文献   
68.
周欣 《心理科学》2003,26(1):82-86
本研究中运用了两个实验探讨数数干预和测查条件对儿童在集合比较中运用数数的影响。干预对3岁儿童(M=3:9)没有影响。在平均年龄为4岁4个月时.干预组儿童比控制组儿童更倾向于用数数比较集合.自然组儿童也比传统组更倾向于用数数。许多4岁儿童在无干预时不用数数可能是因为,1)不知数数比视觉性比较更有效,或2)他们在集合比较中的数数极易受测查情景因素的影响。儿童在集合比较中的数数运用与他们的数数水平密切关联。  相似文献   
69.
This study examined the relation between career adaptability (CA), promotability, and career satisfaction (CS), and their impacts on turnover intentions (TI). Eight hypotheses were proposed. Based on data collected from a sample of 431 employees in Macau, career adaptability was significantly and positively related to both promotability and CS after controlling for the influences of demographic variables including age, gender, education and tenure. CA, promotability and CS were also significantly and negatively linked to TI. The results further revealed that promotability and CS mediated the effect of CA on TI. The study contributed new insights that may inform career development and retention of employees. Practical implications on how to retain employees were discussed.  相似文献   
70.
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