Phonological processing and emergent literacy in younger and older preschool children

Phonological awareness, phonological memory, and phonological access to lexical storage play important roles in acquiring literacy. We examined the convergent, discriminant, and predictive validity of these phonological processing abilities (PPA) in 389 3-, 4-, and 5-year-old children. Confirmatory factor analysis supported the validity of each PPA as separate from general cognitive ability and separate from each other. Multigroup structural equation modeling (SEM) with mean structure demonstrated that older preschoolers have better developed latent PPA than younger preschoolers but that the structure of PPA is equivalent. RAN was found uniquely associated with letter knowledge and text discrimination in younger preschoolers, and PA was found uniquely associated with word reading skills in older preschoolers. Finally, general cognitive ability was only indirectly associated with emergent literacy via PPA. These results highlight the importance of PPA in the early literacy development of English-speaking preschool children.     

The self-concept level of black adolescents with and without African names

The self-concept level of Black adolescents with African names was explored. Black males with and without African names were first identified. All participants and their parents were then administered the Terrell and Taylor Black Ideology Scale and the Coopersmith Self-Esteem Inventory. Differences between groups on the self-concept measures were then examined using a one way MANOVA with parents' scores on the self-concept measures serving as covariates. Significant differences were found between groups. Supplemental analyses revealed no differences between groups on the Coopersmith. However, adolescents with African names had significantly higher scores on the Black self-concept scales than did those without African names.     

Effects of race of examiner and type of reinforcement on the intelligence test performance of lower-class black children

This study examined the effects of race of examiner and type of reinforcement upon the WISC-R performance of lower-class black children. A total of 120 black males were selected and assigned to either a white or black examiner to form two groups. Within each group, children were given no reinforcement, tangible reinforcement, traditional social reinforcement, or culturally relevant social reinforcement after each correct response. Children given tangible rewards, regardless of race of examiner, obtained significantly higher scores than did children given no reinforcement or children given traditional social reinforcement. Also, children given culturally relevant social reinforcement by a black examiner obtained significantly higher scores than did children given culturally relevant reinforcement by the white examiner.     

Contextual effects on predicting risk for reading difficulties in first and second grade

This study utilized early reading assessment data from a randomized trial of 210 urban and rural schools in Texas to examine contextual effects on risk prediction in first and second grade. The primary objective was to examine the roles of (a) individual differences, (b) the grade 1 classroom, and (c) the pairing of first and second grade teachers in determining grade 2 outcomes in word reading and fluency. A second objective was to investigate whether the administration format of the assessment (paper, paper plus desktop, handheld plus desktop) or the level of teacher support (web mentoring, no mentoring) moderated the prediction. These moderator variables proved not to be significant. Subsequent analyses found that a combination of student pretest and mean of pretest classroom was a better predictor than student pretest alone. Additionally, the effect of student scores varied by teacher-pair. On average, intraclass correlations (ICCs) ranged from 6% to 17%. Differences in ICCs at the classroom level were much greater than at the school level, and differences in urban schools were twice that of rural schools.     

Geometrical effects in microfluidic-based microarrays for rapid, efficient single-cell capture of mammalian stem cells and plant cells

In this paper, a detailed numerical and experimental investigation into the optimisation of hydrodynamic micro-trapping arrays for high-throughput capture of single polystyrene (PS) microparticles and three different types of live cells at trapping times of 30 min or less is described. Four different trap geometries (triangular, square, conical, and elliptical) were investigated within three different device generations, in which device architecture, channel geometry, inter-trap spacing, trap size, and trap density were varied. Numerical simulation confirmed that (1) the calculated device dimensions permitted partitioned flow between the main channel and the trap channel, and further, preferential flow through the trap channel in the absence of any obstruction; (2) different trap shapes, all having the same dimensional parameters in terms of depth, trapping channel lengths and widths, main channel lengths and widths, produce contrasting streamline plots and that the interaction of the fluid with the different geometries can produce areas of stagnated flow or distorted field lines; and (3) that once trapped, any motion of the trapped particle or cell or a shift in its configuration within the trap can result in significant increases in pressures on the cell surface and variations in the shear stress distribution across the cell’s surface. Numerical outcomes were then validated experimentally in terms of the impact of these variations in device design elements on the percent occupancy of the trapping array (with one or more particles or cells) within these targeted short timeframes. Limitations on obtaining high trap occupancies in the devices were shown to be primarily a result of particle aggregation, channel clogging and the trap aperture size. These limitations could be overcome somewhat by optimisation of these device design elements and other operational variables, such as the average carrier fluid velocity. For example, for the 20 μm polystyrene microparticles, the number of filled traps increased from 32% to 42% during 5–10 min experiments in devices with smaller apertures. Similarly, a 40%–60% reduction in trapping channel size resulted in an increase in the amount of filled traps, from 0% to almost 90% in 10 min, for the human bone marrow derived mesenchymal stem cells, and 15%–85% in 15 min for the human embryonic stem cells. Last, a reduction of the average carrier fluid velocity by 50% resulted in an increase from 80% to 92% occupancy of single algae cells in traps. Interestingly, changes in the physical properties of the species being trapped also had a substantial impact, as regardless of the trap shape, higher percent occupancies were observed with cells compared to single PS microparticles in the same device, even though they are of approximately the same size. This investigation showed that in microfluidic single cell capture arrays, the trap shape that maximizes cell viability is not necessarily the most efficient for high-speed single cell capture. However, high-speed trapping configurations for delicate mammalian cells are possible but must be optimised for each cell type and designed principally in accordance with the trap size to cell size ratio.     

An analysis of the role of users in the total r&d portfolios of scientific instrument firms

This paper describes a real-time investigation of the total new product portfolios of nine product departments in the scientific instrument industry. It was found that within these portfolios only a few new products represented a major advance in functional performance. Most new products offered only incremental performance improvement, and many ‘new’ products were direct copies of competitors ' offerings.The scientific instrument innovation process is described in seven stages: recognition of need, invention of solution, prototype development, use in application, precommercial information dissemination, product engineering, and commercialization. In those cases where users were involved in the majority of the first five stages of the innovation process, the innovation was either a major functional improvement or a minor improvement that had not been initiated as a direct response to a competitor's product introduction. Direct copies and minor improvements that were competitive responses are notable for the absence of user involvement in the innovation process.Finally, the decision of a manufacturer to commercialize an innovation was unrelated to the level of user activity in the prior stages of the innovation process.