Using New Proximity Measures With Hierarchical Cluster Analysis to Detect Multidimensionality

A new approach for partitioning test items into dimensionally distinct item clusters is introduced. The core of the approach is a new item-pair conditional-covariance-based proximity measure that can be used with hierarchical cluster analysis. An extensive simulation study designed to test the limits of the approach indicates that when approximate simple structure holds, the procedure can correctly partition the test into dimensionally homogeneous item clusters even for very high correlations between the latent dimensions. In particular, the procedure can correctly classify (on average) over 90% of the items for correlations as high as .9. The cooperative role that the procedure can play when used in conjunction with other dimensionality assessment procedures is discussed.     

The dynamics of the impact and coalescence of droplets on a solid surface

A simple experimental setup to study the impact and coalescence of deposited droplets is described. Droplet impact and coalescence have been investigated by high-speed particle image velocimetry. Velocity fields near the liquid-substrate interface have been observed for the impact and coalescence of 2.4 mm diameter droplets of glycerol∕water striking a flat transparent substrate in air. The experimental arrangement images the internal flow in the droplets from below the substrate with a high-speed camera and continuous laser illumination. Experimental results are in the form of digital images that are processed by particle image velocimetry and image processing algorithms to obtain velocity fields, droplet geometries, and contact line positions. Experimental results are compared with numerical simulations by the lattice Boltzmann method.     

Promoting secondary school students’ evaluation of source features of multiple documents

The current research examined whether instructional activities centering on contrasting cases promoted secondary school students’ evaluations of source features present in a multiple-documents inquiry context. Two hypothetical students’ document evaluation strategy protocols were designed: One featured more sophisticated strategies commonly enacted by experts and better college students and a second featured less sophisticated strategies commonly enacted by secondary school students. A series of classroom-based activities required that students compare/contrast the two protocols to decide which were the best strategies when analyzing multiple scientific documents and why. The findings demonstrated that students who previously participated in the intervention activities included more scientific concepts from more useful documents when generating essay responses from memory, displayed better rankings of the usefulness of the set of multiple documents, and offered more principled justifications based on source feature evaluations of trustworthiness compared to students who instead received typical classroom instruction. We discuss the instructional implications of a contrasting-cases approach in facilitating secondary school students’ usage of source features within multiple-documents inquiry contexts.     

Effects of an Early Family Intervention on Children's Memory: The Mediating Effects of Cortisol Levels

Developmental psychologists have long been concerned with the ways that early adversity influences children's long-term outcomes. In the current study, activity of the hypothalamic–pituitary–adrenal axis of medically at-risk (e.g., preterm) infants was measured as a result of maternal participation in a novel cognitively based home visitation program (versus a Healthy Start home visitation program). Maternal participation in the cognitive intervention predicted lower basal cortisol levels among infants—with reduced levels of maternal avoidance/withdrawal serving as a mediator of this relation. Lower cortisol levels in infancy, in turn, predicted higher verbal short-term memory (STM) at age 3. STM represents a cognitive ability that has importance for children's later educational outcomes. Findings provide experimental evidence concerning the pathway by which an early intervention may produce hormonal changes that can, in turn, influence children's learning outcomes.     

The system of intellectual support for making decisions by planning and training

The paper is devoted to the problem of the qualitative training of management specialists. New methods and instruments permitting the quality of accepted decisions to be heightened are described. It is suggested to use an SISDM containing the functions of the system as an instrument for planning decisions and training in decision making with the use of computerized methods for the active teaching of the method for the analysis of concrete situations and management games.     

A systematic approach to analysing sports performance

A systematic approach to the analysis of sporting events is discussed. The basic tenet is that objective quantification of critical events is required for a complete analysis. This approach encompasses diverse areas of methodology and research, such as quantification, biomechanics and physiology. The theoretical underpinning are behavioural, in so far as athletes produce observable behaviour that can be quantified and ultimately changed. Several areas of analysis are linked together in a general framework and each one of these areas is dealt with in detail.