Estimating R 2 Shrinkage in Multiple Regression: A Comparison of Different Analytical Methods

The effectiveness of various analytical formulas for estimating R ² shrinkage in multiple regression analysis was investigated. Two categories of formulas were identified: estimators of the squared population multiple correlation coefficient (ρ²) and those of the squared population cross-validity coefficient (ρ_c ²). The authors conducted a Monte Carlo experiment to investigate the effectiveness of the analytical formulas for estimating R ² shrinkage, with 4 fully crossed factors (squared population multiple correlation coefficient, number of predictors, sample size, and degree of multicollinearity) and 500 replications in each cell. The results indicated that the most widely used Wherry formula (in both SAS and SPSS) is probably not the most effective analytical formula for estimating ρ². Instead, the Pratt formula and the Browne formula outperformed other analytical formulas in estimating ρ² and ρ_c ², respectively.     

A Note on Extending Steiger's (1998) Multiple Sample RMSEA Adjustment to Other Noncentrality Parameter-Based Statistics

This article considers the implications for other noncentrality parameter-based statistics from Steiger's (1998) multiple sample adjustment to the root mean square error of approximation (RMSEA) measure. When a structural equation model is fitted simultaneously in more than 1 sample, it is shown that the calculation of the noncentrality parameter used in tests of approximate fit and in point and interval estimators of other noncentral fit statistics (except the expected cross-validation index) also requires a likeminded adjustment. Furthermore, it is shown that an adjustment is needed in multiple sample models for correctly calculating MacCallum, Browne, and Sugawara's (1996) approach to power analysis. The accuracy of these proposals is investigated and demonstrated in a small Monte Carlo study in which particular attention is paid to using appropriately constructed covariance matrices that give specified nonzero population discrepancy values under maximum likelihood estimation.     

Which aspects of processing text mediate genetic effects?

Genetic influences on reading are investigated in a sample of 285, 13 year old twins. Using a multiple regression procedure, the heritability of disability (h _g ² ) for Reading Recognition was found to be non-significant. However the h _g ² for spelling disability was found to be 0.58 (P<0.05), after controlling for individual differences in IQ. The twins in this study were an unselected sample from the general population. Therefore it was possible to estimate h _g ² for differing degrees of severity of disability. These analyses showed that for spelling but not for Reading Recognition or Reading Composite, there were substantial genetic contributions to all levels of disability. For indices of Orthographic Coding there were no significant values of h _g ² . In contrast measures of Phonological Coding and Homophone Recognition have consistently high values of h _g ² . More detailed analyses suggested that there were possibly two independent aspects of phonological ability, each influenced by genetic factors.     

重新启动的FOM方法求解多右端位移方程组

The seed method is used for solving multiple linear systems A^(i) x^(i) = b^(i) for l≤ i≤ s , where the coefficient matrix A^(i) and the right-hand side b^(i) are different in general. It is known that the CG method is an effective method for symmetric coefficient matrices A^(i) . In this paper, the FOM method is employed to solve multiple linear systems when coefficient matrices are non-symmetric matrices. One of the systems is selected as the seed system which generates a Krylov subspace, then the residuals of other systems are projected onto the generated Krylov subspace to get the approximate solutions for the unsolved ones. The whole process is repeated until all the systems are solved.     

Quantitative trait loci analysis for rice seed vigor during the germination stage

Seed vigor is an important characteristic of seed quality, and rice cultivars with strong seed vigor are desirable in direct-sowing rice production for optimum stand establishment. In the present study, the quantitative trait loci (QTLs) of three traits for rice seed vigor during the germination stage, including germination rate, final germination percentage, and germination index, were investigated using one recombinant inbred line (RIL) population derived from a cross between japonica Daguandao and indica IR28, and using the multiple interval mapping (MIM) approach. The results show that indica rice presented stronger seed vigor during the germination stage than japonica rice. A total of ten QTLs, and at least five novel alleles, were detected to control rice seed vigor, and the amount of variation (R ²) explained by an individual QTL ranged from 7.5% to 68.5%, with three major QTLs with R ²>20%. Most of the QTLs detected here are likely to coincide with QTLs for seed weight, seed size, or seed dormancy, suggesting that the rice seed vigor might be correlated with seed weight, seed size, and seed dormancy. At least five QTLs are novel alleles with no previous reports of seed vigor genes in rice, and those major or minor QTLs could be used to significantly improve the seed vigor by marker-assisted selection (MAS) in rice.     

Reviews

Books reviewed: Wyse, Dominic, Primary Writing Browne, Naima, Young Children’s, Literacy Development and the Role of Televisual Texts Geekie, P., Understanding Literacy Development     

The Superiority of Factor Scores as Predictors

Common factor scores were compared to unfactored data-level variables as predictors in terms of the correlation of a criterion with the predicted value in multiple regression equations applied to replication (cross-validation) samples. Data were generated by computer to provide populations with three different degrees of common variance inherent in their predictor variable intercorrelation matrices. Two replication populations differing from the original by specified amounts in their intercorrelation matrices were created for each common variance level. Results indicated that shrinkage was less for factor scores than for data-level variables for all combinations of common variance and difference of replication population. Moreover, the actual correlation describing accuracy of prediction was higher for factor scores than for data-level variables at the extreme conditions of common variance and difference of replication population.     

Modeling Dynamic Functional Neuroimaging Data Using Structural Equation Modeling

The aims of this study were to present a method for developing a path analytic network model using data acquired from positron emission tomography. Regions of interest within the human brain were identified through quantitative activation likelihood estimation meta-analysis. Using this information, a “true” or population path model was then developed using Bayesian structural equation modeling. To evaluate the impact of sample size on parameter estimation bias, proportion of parameter replication coverage, and statistical power, a 2 group (clinical/control) × 6 (sample size: N = 10, N = 15, N = 20, N = 25, N = 50, N = 100) Markov chain Monte Carlo study was conducted. Results indicate that using a sample size of less than N = 15 per group will produce parameter estimates exhibiting bias greater than 5% and statistical power below .80.     

应用量化参数研究CCK受体拮抗剂的结构与活性的相关性

应用MM+分子力学法对24个CCK受体拮抗剂类似物进行结构优化,然后应用量子化学AM1法计算了24个CCK受体拮抗剂类似物的部分量化参数,并通过逐步回归分析方法建立了量化指数与CCK受体拮抗剂活性之间的定量相关模型,取得了良好的结果,其模型相关系数为R=0.886;继以留一法(Leave-one-out,LOO)进行交互检验,复相关系数为R2cv=0.539,说明定量相关模型具有良好的稳定性和预测能力.发现CCK受体拮抗剂的活性部位主要在分子的A、B环及其支链C21和N20上.     

A comparison of the Stanford-Binet Intelligence Scale and the McCarthy Scales of Children's Abilities with preschool children

The purpose of the present study was to determine the degree to which performance on the McCarthy Scaies of Children's Abilities correlated with performance on the Stanford-Binet for a group of preschoolers. The sample consisted of 44 children ranging in age from 3–11 to 5–4. It was found that the General Cognitive Index scores of the McCarthy Scales correlated well with the Stanford-Binet IQ scores, r^xy = .90. However, 40 of the 44 subjects scored higher on the Stanford-Binet than on the McCarthy Scales.     

Gas Absorption and Mass Transfer in a Pore-Array Intensified Tube-in-Tube Microchannel

A pore-array intensified tube-in-tube microchannel (PA-TMC), which is characterized by high throughput and low pressure drop, was developed as a gas–liquid contactor. The sulfite oxidation method was used to determine the oxygen efficiency (φ) and volumetric mass transfer coefficient (k_La) of PA-TMC, and the mass transfer amount per unit energy (ε) was calculated by using the pressure drop. The effects of structural and operating parameters were investigated systematically, and the two-phase flow behavior was monitored by using a charge-coupled device imaging system. The results indicated that the gas absorption efficiency and mass transfer performance of the PA-TMC were improved with increasing pore number, flow rate, and number of helical coil turns and decreasing pore size, row number, annular size, annular length, and surface tension. The φ, ε and k_La of PA-TMC could reach 31.3%, 1.73 × 10⁻⁴ mol/J, and 7.0 s⁻¹, respectively. The Sherwood number was correlated with the investigated parameters to guide the design of PA-TMC in gas absorption and mass transfer processes.

     

外电场作用下柔性模型水的分子动力学模拟

1 Introduction Water is the most common liquid in nature and it isalso i mportant in numerous chemical and biologicalprogresses . With the availability of computers , MonteCarlo (MC) and molecular dynamics (MD) si mulationshave beenintroduced and efforts have been devoted toexamining the microscopic structure and dynamicproperties of liquid water utilizing computer si mula-tions[1-8].It is known that liquid water is totally con-nected by random tetrahedral hydrogen-bonds net- work[1 ,2]. Ho…     

Estimation method for mixed-effect coefficient semiparametric regression model

Consider the mixed-effect coefficient semiparametric regression modelZ=X'α+Y'β+g(T)+e, whereX, Y andT are random vectors onR ^p×R ^q×[0, 1], α is a p-dimensional fixed-effect parameter, β is a q-dimensional random-effect parameter (Eβ=b, Cov(β)=Σ),g(.) is an unknown function on [0, 1], e is a random error with mean zero and variance σ², and (X, Y, T) and (β,e), β ande are mutually independent. We estimate α,b andg(.) by the nearest neighbor and the least square method. In this paper, we prove that estimations of α,b have asymptotic normality and obtain the best convergence raten ^−1/3 for the estimation ofg(.). Project supported by the NSFC and the Natural Science Foundation of Zhejiang Province.     

An evaluation of outcomes following the replacement of traditional histology laboratories with self‐study modules

Changes in medical school curricula often require educators to develop teaching strategies that decrease contact hours while maintaining effective pedagogical methods. When faced with this challenge, faculty at the University of Cincinnati College of Medicine converted the majority of in‐person histology laboratory sessions to self‐study modules that utilize multiple audiovisual modalities and a virtual microscope platform. Outcomes related to this shift were investigated through performance on in‐house examinations, results of the United States Medical Licensing Examination^® (USMLE^®) Step 1 Examination, and student feedback. Medical School College Admissions Test^® (MCAT^®) scores were used as a covariate when comparing in‐house examinations. Results revealed no significant change in performance on in‐house examinations when the content being assessed was controlled (F(2, 506) = 0.676, P = 0.51). A significant improvement in overall practical examination grade averages was associated with the self‐study modules (F(6, 1164) = 10.213, P < 0.01), but gradual changes in examination content may explain this finding. The histology and cell biology portion of USMLE Step 1 Examination remained consistent throughout the time period that was investigated. Student feedback regarding the self‐study modules was positive and suggested that features such as instructor narrated videos were an important component of the self‐study modules because they helped recreate the experience of in‐person laboratory sessions. Positive outcomes from the student perspective and no drop in examination performance suggests that utilizing self‐study modules for histology laboratory content may be an option for educators faced with the challenge of reducing contact hours without eliminating content. Anat Sci Educ 10: 276–285. © 2016 American Association of Anatomists.     

The effects of need satisfaction on EFL online learner satisfaction

This study explored the effects of need satisfaction (autonomy, competence, and relatedness) on English as a foreign language (EFL) online learner satisfaction and validated the Chinese versions of the need satisfaction scale (NSS) and online learner satisfaction scale (OLSS). We collected data from a questionnaire administered to 199 EFL students at a Taiwanese university. The Cronbach’s alpha reliability coefficient for NSS was .90 and .91 for OLSS. For NSS, the principal component analysis (PCA) resulted in a three-factor solution that accounted for 61.31% of the variance. Regarding OLSS, PCA resulted in a two-factor solution that accounted for 63.17% of the variance. A multiple regression analysis revealed that three independent variables (autonomy, competence, and relatedness) were predictors of EFL online learner satisfaction (F(3,?191) = 85.14, P < .001, R² = .57), with competence the best predictor of online learner satisfaction, followed by relatedness and autonomy. The paper concludes with implications of these results.     

Associations of Number Line Estimation With Mathematical Competence: A Meta‐analysis

The number line estimation task is widely used to investigate mathematical learning and development. The present meta‐analysis statistically synthesized the extensive evidence on the correlation between number line estimation and broader mathematical competence. Averaged over 263 effect sizes with 10,576 participants with sample mean ages from 4 to 14 years, this correlation was r = .443. The correlation increased with age, mainly because it was higher for fractions than for whole numbers. The correlation remained stable across a wide range of task variants and mathematical competence measures (i.e., counting, arithmetic, school achievement). These findings demonstrate that the task is a robust tool for diagnosing and predicting broader mathematical competence and should be further investigated in developmental and experimental training studies.     

The role of plausible values in large-scale surveys

In large-scale assessment programs such as NAEP, TIMSS and PISA, students' achievement data sets provided for secondary analysts contain so-called plausible values. Plausible values are multiple imputations of the unobservable latent achievement for each student. In this article it has been shown how plausible values are used to: (1) address concerns with bias in the estimation of certain population parameters when point estimates of latent achievement are used to estimate those population parameters; (2) allow secondary data analysts to employ standard techniques and tools (e.g., SPSS, SAS procedures) to analyse achievement data that contains substantial measurement error components; and (3) facilitate the computation of standard errors of estimates when the sample design is complex. The advantages of plausible values have been illustrated by comparing the use of maximum likelihood estimates and plausible values (PV) for estimating a range of population statistics.     

The Stanislavsky system for actors

The British Cicero, or, A Selection of the Most Admired Speeches in the English Language .... to which is prefixed, An Introduction to the Study and Practice of Eloquence. By Thomas Browne, LL. D. Three volumes. London, Printed for Longman, Hurst, Rees, and Orme, 1808.

Aelius Aristide, et La Sophistique Dans La Province D'Asie Au He Siècle De Notre Ere. Boulanger, André, Paris, 1923; pp. xiv, 504.

Rhetores Latini Minores. Carolus Halm, Leipsig, 1863; pp. xvi, 658.     

Positive Youth Development and Resilience: Growth Patterns of Social Skills Among Youth Investigated for Maltreatment

Maltreated children are a vulnerable population, yet many of these youth follow positive developmental pathways. The primary aim was to identify social skills growth trajectories among at‐risk youth to understand processes underlying resilience. Nationally representative, longitudinal data from 1,179 families investigated for child maltreatment (M_age = 12.75) were obtained from the National Survey of Child and Adolescent Well‐Being. Four trajectories were identified—stress‐resistant, emergent resilience, breakdown, and unresponsive‐maladaptive. Protective resources from multiple levels of the youth ecology (individual, family, school, and social service) predicted positive growth social skills trajectories. Resilience process and attendant positive outcomes in multiple domains of functioning were evident among the stress‐resistant and emergent resilience trajectories. Results underscore the saliency of social skills development for resilient outcomes in youth.     

Reading disability in boys and girls: No evidence for a differential genetic etiology

In order to test the hypothesis that genetic influences are moreimportant as a cause of reading disability in girls than in boys,composite reading performance data from identical and fraternal twinpairs were analyzed using both concordance and multiple regressionmethods. The sample included 206 identical (99 male, 107 female), 159same-sex fraternal (90 male, 69 female), and 117 opposite-sex fraternaltwin pairs, in which at least one member of each pair had readingdifficulties. Although the difference between the concordance rates forreading disabilities in female identical and same-sex fraternal twinpairs was somewhat greater (65% for identical twins vs.32% for fraternal twins) than the difference in concordance ratesfor boys (68% vs. 39%), loglinear analysis of thesecategorical data revealed that the interaction between sex, zygosity,and concordance was not significant (p > 0.70). Moreover,the heritability of reading disability(h ² _g) estimated from regression analysisof the reading performance data in males was nearly identical to that infemales (h ² _g = 0.58 and 0.59,respectively; p > 0.90). Thus, results of this studyprovide little or no evidence for the hypothesis of greater geneticinfluence on reading difficulties in girls than in boys.