Models and Strategies for Factor Mixture Analysis: An Example Concerning the Structure Underlying Psychological Disorders

The factor mixture model (FMM) uses a hybrid of both categorical and continuous latent variables. The FMM is a good model for the underlying structure of psychopathology because the use of both categorical and continuous latent variables allows the structure to be simultaneously categorical and dimensional. This is useful because both diagnostic class membership and the range of severity within and across diagnostic classes can be modeled concurrently. Although the conceptualization of the FMM has been explained in the literature, the use of the FMM is still not prevalent. One reason is that there is little research about how such models should be applied in practice and, once a well-fitting model is obtained, how it should be interpreted. In this article, the FMM is explored by studying a real data example on conduct disorder. By exploring this example, this article aims to explain the different formulations of the FMM, the various steps in building a FMM, and how to decide between an FMM and alternative models.     

Spelling,Reading Abilities and Speech Perception in Deaf Children with a Cochlear Implant

ABSTRACT

This study aims to compare word spelling outcomes for French-speaking deaf children with a cochlear implant (CI) with hearing children who matched for age, level of education and gender. A picture written naming task controlling for word frequency, word length, and phoneme-to-grapheme predictability was designed to analyze spelling productions. A generalized linear mixed model on the percentage of correct spelling revealed an effect of participant’s reading abilities, but no effect of hearing status. Word frequency and word length, but not phoneme-to-grapheme predictability, contributed to explaining the spelling variance. Deaf children with a CI made significantly less phonologically plausible errors and more phonologically unacceptable errors when compared to their hearing peers. Age at implantation and speech perception scores were related to deaf children’s errors. A good word spelling level can be achieved by deaf children with a CI, who nonetheless use less efficiently the phoneme-to-grapheme strategy than do hearing children.     

The Growth of Phonological Awareness by Children With Reading Disabilities: A Result of Semantic Knowledge or Knowledge of Grapheme-Phoneme Correspondences?

According to the Lexical Restructuring Model (Metsala & Walley, 1998 Metsala, J. L. and Walley, A. C. 1998. “Spoken vocabulary growth and the segmental restructuring of lexical representation: Precursors to phonemic awareness and early reading ability”. In Word recognition in beginning literacy, Edited by: Metsala, J. L. and Ehri, L. C. 89–120. Mahwah, NJ: Lawrence Erlbaum Associates, Inc.  [Google Scholar]), children move from holistic representations of words, to syllabic representations, and finally to phonemic representations through a restructuring process driven by their developing lexical base. In contrast, the psycholinguistic grain size theory put forth by Ziegler and Goswami (2005) Ziegler, J. C. and Goswami, U. 2005. Reading acquisition, developmental dyslexia, and skilled reading across languages: A psycholinguistic grain size theory.. Psychological Bulletin, 131: 3–29. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] suggests that the awareness of individual phonemes is not possible without direct literacy instruction. The purpose of this study was to examine whether semantic knowledge and/or knowledge of grapheme/phoneme correspondences influenced the acquisition of word-blending skills by a sample of children with a reading disability. Participants were 211 second-grade and third-grade students from public elementary schools who were assigned to a reading intervention. Hierarchical Linear Modeling techniques were used to model individual growth curves of word-blending skills. Overall, findings support the psycholinguistic grain size theory of reading and suggest that instruction in the relationship between orthographic patterns and their corresponding sounds is necessary for the development of phonological awareness.     

The ecology of interactive learning environments: situating traditional theory

In educational discourse on human learning (i.e. the result of experience) and development (i.e. the result of maturation), there are three fundamental theoretical frameworks, – behaviourism, cognitivism and constructivism, each of which have been applied, with varying degrees of success, in online environments. An ecological framework of human learning and development in interactive learning environments is proposed. Such an inclusive paradigm organizes the fundamental theoretical assumptions of behaviourism (i.e. automated learning), cognitivism (i.e. recall, understanding, analysis, synthesis, evaluation, creativity, problem solving) and constructivism (i.e. private and shared meaning). Based on review of the literature, behaviourism is best conceptualized as a learning theory; constructivist theoretical assumptions are best applied to cognitive development including private online experience (cognitive constructivism) and shared online experience (social constructivism). Cognitivism is a particularly relevant theoretical orientation in understanding both human learning and development in interactive learning environments.     

Influence of Process Parameters on Chlorinated Biocide Decontamination by li-CO2 on Artificially Contaminated Model Materials

ABSTRACT

Previously, heavy use of biocides for the treatment of objects made of organic materials in museum collections (e.g. ethnographic, historical collections) was very common. Now suitable decontamination methods/technologies are being sought. A decontamination treatment by li-CO₂ was optimized that considered the specific requirements of museum objects. The treatment was tested on model materials artificially contaminated with biocide solutions containing dichlorodiphenyltrichloroethane (DDT), pentachlorophenol (PCP), lindane, and permethrin or cypermethrin. High decontamination was achieved for DDT, lindane, PCP, and permethrin on artificially biocide loaded wool and wood model materials. Optimal process parameter settings for li-CO₂ decontamination include a single 30?min cycle for woolen materials and three sequential 30?min cycles each for wood. These methods allow a reduction of at least 90% of all biocides for wool and between 70% and 85% for wood. Decontamination of the latter was more effective for less polar biocides as DDT and permethrin. Despite a significant improvement in decontamination for wood using co-solvents such as acetone, ethanol, and methyl tertiary-butyl ether (MTBE), their use is not recommended due to the increased risk of damage to the objects, in particular if a surface coating is present.     

Social media for the community college library

Abstract

This article summarizes the experience of a multi-campus urban community college library developing and managing a social media presence. The author describes the organization of social media efforts, institutional rules that affect implementation of social media, developing themes for content, and other considerations.     

He Asked Me What!?—Using Shared Online Accounts as Training Tools for Distance Learning Librarians

ABSTRACT

This study explores the idea of creating a knowledge base from shared online accounts to use in training librarians who perform distance reference services. Through a survey, follow-up interviews and a case study, the investigators explored current and potential use of shared online accounts as training tools. This study revealed that the participants viewed the concept positively, but many encountered barriers to effectively employing a local knowledge base as a training tool.