Dynamic testing of gifted and average-ability children's analogy problem solving: Does executive functioning play a role?

Article / Letter to editorInstituut Psychologie;Instituut Psychologie;Instituut Psychologie;Instituut Psychologi

Dynamic testing of gifted and average-ability children's analogy problem solving: Does executive functioning play a role?

Article / Letter to editorInstituut Psychologie;Instituut Psychologie;Instituut Psychologie;Instituut Psychologi

Dynamic testing of gifted and average-ability children's analogy problem solving: Does executive functioning play a role?

status: publishe

Dynamic testing of gifted and average-ability children's analogy problem solving: Does executive functioning play a role?

Article / Letter to editorInstituut Psychologie;Instituut Psychologie;Instituut Psychologie;Instituut Psychologi

Computerized process-oriented dynamic testing of children’s ability to reason by analogy using log data

The study investigated the value of process data obtained from a group-administered computerized dynamic test of analogical reasoning, consisting of a pretest-training-posttest design. We sought to evaluate the effects of training on processes and performance, and the relationships between process measures and performance on the dynamic test. Participants were N = 86 primary school children (Mage = 8.11 years, SD = 0.63). The test consisted of constructed-response geometrical analogy items, requiring several actions to construct an answer. Process data enabled scoring of the total time, the time taken for initial planning of the task, the time taken for checking the answer that was provided, and variation in solving time. Training led to improved performance compared to repeated practice, but this improvement was not reflected in task-solving processes. Almost all process measures were related to performance, but the effects of training or repeated practice on this relationship differed widely between measures. In conclusion, the findings seemed to indicate that investigating process indicators within computerized dynamic testing of analogical reasoning ability provided information about children’s learning processes, but that not all processes were affected in the same way by training.Education and Child Studie

Pre-Existing Superbubbles as the Sites of Gamma-Ray Bursts

According to recent models, gamma-ray bursts apparently explode in a wide variety of ambient densities ranging from ~ 10^{-3} to 30 cm^{-3}. The lowest density environments seem, at first sight, to be incompatible with bursts in or near molecular clouds or with dense stellar winds and hence with the association of gamma-ray bursts with massive stars. We argue that low ambient density regions naturally exist in areas of active star formation as the interiors of superbubbles. The evolution of the interior bubble density as a function of time for different assumptions about the evaporative or hydrodynamical mass loading of the bubble interior is discussed. We present a number of reasons why there should exist a large range of inferred afterglow ambient densities whether gamma-ray bursts arise in massive stars or some version of compact star coalescence. We predict that many gamma-ray bursts will be identified with X-ray bright regions of galaxies, corresponding to superbubbles, rather than with blue localized regions of star formation. Massive star progenitors are expected to have their own circumstellar winds. The lack of evidence for individual stellar winds associated with the progenitor stars for the cases with afterglows in especially low density environments may imply low wind densities and hence low mass loss rates combined with high velocities. If gamma-ray bursts are associated with massive stars, this combination might be expected for compact progenitors with atmospheres dominated by carbon, oxygen or heavier elements, that is, progenitors resembling Type Ic supernovae.Comment: 14 pages, no figures, submitted to The Astrophysical Journa

The Fractal Dimension of Projected Clouds

The interstellar medium seems to have an underlying fractal structure which can be characterized through its fractal dimension. However, interstellar clouds are observed as projected two-dimensional images, and the projection of a tri-dimensional fractal distorts its measured properties. Here we use simulated fractal clouds to study the relationship between the tri-dimensional fractal dimension (D_f) of modeled clouds and the dimension resulting from their projected images. We analyze different fractal dimension estimators: the correlation and mass dimensions of the clouds, and the perimeter-based dimension of their boundaries (D_per). We find the functional forms relating D_f with the projected fractal dimensions, as well as the dependence on the image resolution, which allow to estimatethe "real" D_f value of a cloud from its projection. The application of these results to Orion A indicates in a self-consistent way that 2.5 < D_f < 2.7 for this molecular cloud, a value higher than the result D_per+1 = 2.3 some times assumed in literature for interstellar clouds.Comment: 27 pages, 13 figures, 1 table. Accepted for publication in ApJ. Minor change

Optimizing patient risk stratification for colonoscopy screening and surveillance of colorectal cancer: The role for linked data

No abstract available for this article

Constraining ^(26)Al+p resonances using ^(26)Al(^3He,d)^(27)Si

The ^(26)Al(^3He,d)^(27)Si reaction was measured from 0°≤θ_(c.m.)≤35° at E(^3He)=20 MeV using a quadrupole-dipole-dipole-dipole magnetic spectrometer. States in ^(27)Si were observed above the background at 7652 and 7741 keV and upper limits were set for the state at 7592 keV. Implications for the ^(26)Al(p,γ)^(27)Si stellar reaction rate are discussed