Nonstandard log-linear models.

This article demonstrates several useful varieties of nonstandard log-linear models. Some can be derived as nonhierarchical models by deleting lower-order effects in hierarchical models, but most often they will arise as the result of special hypotheses that the researcher wants to test. Three approaches to testing nonstandard models, partitioning chi-square, creating homogeneous subgroups, and the model matrix approach, are illustrated on a variety of data sets. It is assumed that the reader has been exposed to the general area of log-linear models, is familiar with dummy and effect coding of categorical variables in the usual regression framework, and knows how to express models in matrix form. A brief summary of the standard approach to log-linear models and of coding methods is provided for readers needing a review. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Application scenarios for nonstandard log-linear models.

In this article, the authors have 2 aims. First, hierarchical, nonhierarchical, and nonstandard log-linear models are defined. Second, application scenarios are presented for nonhierarchical and nonstandard models, with illustrations of where these scenarios can occur. Parameters can be interpreted in regard to their formal meaning and in regard to their magnitude. The interpretation of the meaning of parameters is the main focus of this article. Design matrices are used to describe the hypotheses tested in models and to illustrate cases in which parameters are interpretable. Also, design matrices are used to show where and how nonstandard models differ from standard hierarchical models. Coding schemes are discussed, in particular, dummy coding and effects coding. Data examples are given with data and models discussed in the literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of log-linear models for assessing differential item functioning in a measure of psychological functioning.

Log-linear models are used to investigate contingency tables that cross-classify respondents according to item response, mental health status (MHS), and the background variables of ethnicity and gender. Specifically, log-linear models are used to examine item validity, defined as an item response by MHS interaction, and differential item functioning (DIF), defined as an interaction between item response and a background variable. The investigation focused on a set of items that measure subjective well-being and coping behavior. Female (n?=?627) and male (n?=?338) respondents represented 3 ethnic groups: African American, Anglo-American, and Hispanic/Latino. Strong evidence of item validity and some evidence of DIF was found. Most of the interaction between item response and either ethnicity or gender occurred among Ss with diminished mental health. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The genealogy of samples in models with selection

We introduce the genealogy of a random sample of genes taken from a large haploid population that evolves according to random reproduction with selection and mutation. Without selection, the genealogy is described by Kingman's well-known coalescent process. In the selective case, the genealogy of the sample is embedded in a graph with a coalescing and branching structure. We describe this graph, called the ancestral selection graph, and point out differences and similarities with Kingman's coalescent. We present simulations for a two-allele model with symmetric mutation in which one of the alleles has a selective advantage over the other. We find that when the allele frequencies in the population are already in equilibrium, then the genealogy does not differ much from the neutral case. This is supported by rigorous results. Furthermore, we describe the ancestral selection graph for other selective models with finitely many selection classes, such as the K-allele models, infinitely-many-alleles models. DNA sequence models, and infinitely-many-sites models, and briefly discuss the diploid case.     

Predictive model selection for repeated measures random effects models using Bayes factors

The random effects model fit to repeated measures data is an extremely common model and data structure in current biostatistical practice. Modern data analysis often involves the selection of models within broad classes of prespecified models, but for models beyond the generalized linear model, few model-selection tools have been actively studied. In a Bayesian analysis, Bayes factors are the natural tool to use to explore these classes of models. In this paper, we develop a predictive approach for specifying the priors of a repeated measures random effects model with emphasis on selecting the fixed effects. The advantage of the predictive approach is that a single predictive specification is used to specify priors for all models considered. The methodology is applied to a pediatric pain data analysis.     

Interviewer consistency in the use of empathic models in personnel selection.

Personnel selection interviewers predicted the responses of applicants to 2 paper and pencil tests. Comparisons were made between these predictions and the responses of applicants (accuracy score), predictions and the responses of interviewers (similarity score). (These scores were referred to collectively as empathy scores.) Statistical analysis of empathy scores and their components indicated marked inter-interviewer inconsistency, which was interpreted to mean that interviewers tend to make errors by resorting to empathy as a basis of decision making. Explicit, actuarial bases of decision making in interviewing are advocated. Results of a follow-up study supported this interpretation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

One-locus two-allele models with maternal (parental) selection

I formulate and study a series of simple one-locus two-allele models for maternal (parental) selection. I show that maternal (parental) selection can result in simultaneous stability of equilibria of different types. Thus, in the presence of maternal (parental) selection the outcome of population evolution can significantly depend on initial conditions. With maternal selection, genetic variability can be maintained in the population even if none of the offspring of heterozygous mothers survive. I demonstrate that interactions of maternal and paternal selection can result in stable oscillations of genotype frequencies. A necessary condition for cycling is strong selection.     

Managerial selection decision models: Examination of configural cue processing.

Evaluation of applicants for middle- and upper-level managerial positions and recommended starting salaries were examined in a sample of 44 male and 24 female line and staff managers. We postulated hypotheses that (a) managers would use job-relevant and job-irrelevant variables in evaluation of applicants, (b) the managers' selection decision models would involve configural cue processing, (c) managers' demographic characteristics would affect their evaluations of applicants for managerial positions, and (d) applicant sex and race would affect starting salary recommendations, after controlling for human capital variables. Subjects viewed videotaped presentations by 16 applicants and evaluated them for the job for which they were applying. Variables of applicant age, sex, race, experience, education, and level of job for which applying were manipulated. The results supported four of the five hypotheses. Job-irrelevant variables were used heavily in selection decisions, and decision models were complex, with multiple interactions among the decision cues. Subject demographic characteristics were the strongest predictors of starting salary recommendations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Faking and personality assessment in personnel selection: Advancing models of faking.

Personality testing is a particularly valuable preemployment assessment tool when one matches personality traits to job requirements. The authors explain that, unlike most other common personnel selection methods, the unique value of personality assessment in personnel selection stems from its tendency to predict the choice to perform, or “will-do” aspects of job performance. The effect of faking on the value of personality testing is discussed, and the authors suggest that personality testing’s contribution to personnel selection could be leveraged if more were known about the psychological process underlying applicant faking behaviour. To this end, the authors present an improved general model of the applicant faking process as well as a new “faking decision tree.” (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Group interviewing for the purpose of selection

Relation between retinal melatonin and corneal mitotic rhythms in the Japanese quail was investigated in experiments manipulating the ocular physiology by treatments with formoguanamine hydrochloride (FG) and eye-lid suture. In experiment 1, we investigated the effects of FG, which is known to induce photoreceptor degeneration, on retinal melatonin and corneal mitotic rhythms. FG-treatment completely abolished the retinal melatonin rhythms in both LD 12:12 and constant darkness (DD), but the corneal mitotic rhythm was maintained with high mitotic rate in darkness under a LD cycle and subjective night under DD. The result suggests that 1) the photoreceptor cells in the retina are the site for melatonin production and/or for the oscillator which drives the circadian rhythm in retinal melatonin, and 2) melatonin is not involved in generation of the corneal mitotic rhythm. In experiment 2, we investigated the effects of eye-lid suture, which is known to induce eye enlargement and bulgy cornea, on the retinal melatonin and corneal mitotic rhythms. Eye-lid suture abolished the corneal mitotic rhythm in both LD and DD, with a high mitotic rate being maintained throughout 24 hr. But retinal melatonin maintained its rhythm with high levels in darkness under a LD cycle and in subjective night under DD. The result suggests that 1) bulgy cornea in the sutured eye was induced by the increase in mitotic rate in the light period, and 2) disappearance of the corneal mitotic rhythm does not have a relation to retinal melatonin. These results suggest that retinal melatonin is not involved in generation of the corneal mitotic rhythm and that there are two circadian clock systems in the eye.     

Animal models and in vitro models for the study of aetiopathogenesis of spondyloarthropathies

Among several animal models, HLA-B27 transgenic rodents proved useful for investigating the interplay between genetic factors and the bacterial environment in the aetiopathogenesis of the spondyloarthropathies (SpA). HLA-B27 transgenic rats spontaneously develop a multisystemic inflammatory disease resembling human SpA. This disease is dependent on the presence of a normal bacterial flora and implicates the immune system. The presence of both T cells and antigen-presenting cells expressing high levels of HLA-B27 seems of critical importance in its pathogenesis. HLA-B27 transgenic mice also develop arthritis, under the influence of the bacterial flora. In both types of model, CD8+ T cells seem not to be necessary, arguing against the 'arthritogenic peptide' hypothesis. In vitro models have been used to study the immune response against bacterial agents and the role of HLA-B27 in human SpA. It appears that an impaired immune response against bacteria could be involved in the triggering of human SpA. HLA-B27 could be implicated at the level of interaction between host cells and bacteria in the driving of a specific immune response against bacterial antigens or as a target of an autoimmune response.     

高等院校研究生教学用书建设的基本原则

教育部关于研究生教学用书建设问题,在有关的文件中作了明确的规定,指出:研究生培养单位的教学用书建设必须围绕“深化研究生教学和科研环节的改革,突出创新能力的培养“这一目标来开展工作.高等院校作为国家创新体系中的人才培养单位,如何适应国家经济建设和社会用人单位的需求,输送大批优秀的高层次人才,说到底培养质量是关键.研究生的培养质量涉及到的因素很多,其中保证教学用书质量是不可忽视的方面之一.……     

Clinical models of chemoprevention for the esophagus

Esophageal SCC is a complex disease involving multiple etiologic factors. A number of preventive approaches could be taken to reduce the occurrence of the disease including changes in lifestyle and improved nutrition, for example, the inclusion of higher quantities of fruits and vegetables in the diet. Unfortunately, these primary prevention approaches are not easily implemented and often fall short in achieving marked reductions in disease occurrence. Chemoprevention offers another approach to reducing the risk of esophageal SCC that is likely to be useful, even though the clinical trials to date have not resulted in the identification of agents that produce marked inhibitory effects on the development of the disease. Given esophageal SCC's complex etiology, it would appear that the most effective chemoprevention strategy would be to employ agents that reduce mutational events associated with exposure to esophageal carcinogens in combination with agents that inhibit the progression of epithelial dysplasia to esophageal SCC. The feasibility of addressing carcinogen-induced mutational events is underscored by the fact that many of the suspected esophageal carcinogens are known, and inhibitors of these carcinogens have been identified in animal model systems. In addition, biomarkers to assess the efficacy of anti-initiation agents, such as levels of phase I and II enzyme activities and of carcinogen: DNA adducts, can be measured. The identification of agents that inhibit the progression of dysplastic lesions to esophageal SCC has proven difficult; however, the results of the trial with ATB and retinamide are encouraging. Clearly, it seems important to identify the active chemopreventives in the antitumor-B herbal mixture. Further studies to identify strong inhibitors of tumor progression in the rat model for esophageal SCC are also needed. Biomarkers of cell proliferation (e.g., PCNA, Ki67), cell differentiation (keratins), apoptosis, gene expression (EGFR, cyclin D1, p53), and nuclear/nucleolar morphometry can be used in studies to assess the efficacy of chemopreventives to either reverse esophageal dysplastic lesions or slow their rate of progression. The development of viable approaches toward the chemoprevention. of esophageal SCC is truly an important goal in view of the poor prognosis of this disease.