2,051 research outputs found
Math Modules: A Theoretical Review and Cognitive Training Programme
The abstract outlines the content of a review on Math Modules a program designed to facilitate the learning of foundational math skills through cognitive training techniques that are based on theory with a special focus on planning and executive functions encompassing cognitive flexibility attentional control and working memory The guiding educational principle is drawn from Vygotsky s concept of zones of proximal development highlighting the belief that children can accomplish tasks with assistance that they may struggle with independently In a way the structure of cognitive training Modules can be viewed as an attempt at construct validity A review of historical roots of Math modules is presented at some length The program begins with the division of training the two key components of math proficiency computing and solving word problems Both rely on five essential skills A specific module on working memory training is cited as an illustrative example of Vygotsky s teaching method A subsequent section summarizes two empirical research studies shedding light on the effectiveness of Math Module training Towards the conclusion the review acknowledges its limitations notably the absence of a comprehensive review of contemporary publications on math cognition and the need for more studies assessing the efficacy of Math Modules The concluding remarks reflect on the concept of validity juxtaposing the number of empirical studies provided with the validation of the construct rooted in Vygotsky and Luria s brain-based research The abstract tangentially touches upon the limits of empirical testimony in the context of the discussed researc
Speed of Processing: Tests and Factor Structure
In the present study we examined Speed of Processing derived from a number of cognitive tests; the response speeds were nearly automatic for tests with minimal cognitive load. The tests were given to students across ages from 8 to 20 in schools and colleges located in various parts of India. The structure of the constellation of the test responses was determined by factor analyses. We report one stable factor of speed for ages 8-10 that splits into two separate but correlated factors for ages 11-14,15-17, and 18-20 representing speed of response to tests that contain letters and numbers versus colour stimuli. Developmental changes in response speed across the four adjacent age groups were examined; the trajectory was not consistently incremental, especially for naming colours that did not increase beyond age 11-14.In conclusion, a fairly reasonable deconstruction of the concepts of RAN has been presented in this report. The major components are encoding and articulation, and the necessity of distinguishing alpha-numeric naming time and colour naming. The later requires the additional time for semantic access. At the end, we suggest that in a follow-up research RAN(alpha-numeric&colour) should be viewed as a part of a broader cognitive speed of processing.Our objective is to determine the association between tests of basic executive processes such as cognitive flexibility,attention &inhibition and working memory on the one hand and speed on the other.Consequently not to search for the tests that would not involve speed, but be aware of the value of the correlation of an executive test with sp eed.This will be useful information or example in investigations into the effect of ageing on executive functions. A worthy agenda for future research. Keywords: Rapid Automatic Naming(RAN),Developmental Changes, Executive Functions DOI: 10.7176/JEP/13-30-11 Publication date:October 31st 202
Negative specific heat in a thermodynamic model of multifragmentation
We consider a soluble model of multifragmentation which is similar in spirit
to many models which have been used to fit intermediate energy heavy ion
collision data. In this model is always positive but for finite nuclei
can be negative for some temperatures and pressures. Furthermore,
negative values of can be obtained in canonical treatment. One does not
need to use the microcanonical ensemble. Negative values for can persist
for systems as large as 200 paticles but this depends upon parameters used in
the model calculation. As expected, negative specific heats are absent in the
thermodynamic limit.Comment: Revtex, 13 pages including 6 figure
Nuclear liquid-gas phase transition within the lattice gas model
We study the nuclear liquid-gas phase transition on the basis of a
two-component lattice gas model. A Metropolis type of sampling method is used
to generate microscopic states in the canonical ensemble. The effective
equation of state and fragment mass distributions are evaluated in a wide range
of temperatures and densities. A definition of the phase coexistence region
appropriate for mesoscopic systems is proposed. The caloric curve resulting
from different types of freeze-out conditions are presented.Comment: 13 pages including 4 figure
Quantum Lifetime of Two-Dimensional Holes
The quantum lifetime of two-dimensional holes in a GaAs/AlGaAs double quantum
well is determined via tunneling spectroscopy. At low temperatures the lifetime
is limited by impurity scattering but at higher temperatures hole-hole Coulomb
scattering dominates. Our results are consistent with Fermi liquid theory, at
least up to r_s = 11. At the highest temperatures the measured width of the
hole spectral function becomes comparable to the Fermi energy. A new,
tunneling-spectroscopic, method for determining the in-plane effective mass of
the holes is also demonstrated.Comment: 5 pages, 4 figures. Published versio
Model of multifragmentation, Equation of State and phase transition
We consider a soluble model of multifragmentation which is similar in spirit
to many models which have been used to fit intermediate energy heavy ion
collision data. We draw a p-V diagram for the model and compare with a p-V
diagram obtained from a mean-field theory. We investigate the question of
chemical instability in the multifragmentation model. Phase transitions in the
model are discussed.Comment: Revtex, 9 pages including 6 figures: some change in the text and Fig.
Temperature dependent resistivity of spin-split subbands in GaAs 2D hole system
We calculate the temperature dependent resistivity in spin-split subbands
induced by the inversion asymmetry of the confining potential in GaAs 2D hole
systems. By considering both temperature dependent multisubband screening of
impurity disorder and hole-hole scattering we find that the strength of the
metallic behavior depends on the symmetry of the confining potential (i.e.,
spin-splitting) over a large range of hole density. At low density above the
metal-insulator transition we find that effective disorder reduces the
enhancement of the metallic behavior induced by spin-splitting. Our theory is
in good qualitative agreement with existing experiments
Coupling of thermal and mass diffusion in regular binary thermal lattice-gases
We have constructed a regular binary thermal lattice-gas in which the thermal
diffusion and mass diffusion are coupled and form two nonpropagating diffusive
modes. The power spectrum is shown to be similar in structure as for the one in
real fluids, in which the central peak becomes a combination of coupled entropy
and concentration contributions. Our theoretical findings for the power spectra
are confirmed by computer simulations performed on this model.Comment: 5 pages including 3 figures in RevTex
Statistical Models of Nuclear Fragmentation
A method is presented that allows exact calculations of fragment multiplicity
distributions for a canonical ensemble of non-interacting clusters.
Fragmentation properties are shown to depend on only a few parameters.
Fragments are shown to be copiously produced above the transition temperature.
At this transition temperature, the calculated multiplicity distributions
broaden and become strongly super-Poissonian. This behavior is compared to
predictions from a percolation model. A corresponding microcanonical formalism
is also presented.Comment: 12 pages, 5 figure
New Solution of D=11 Supergravity on S^7 from D=4
A new static partially twisted solution of N=4, SO(4) gauged supergravity in
D=11 is obtained in this work using Cveti\^c et al embedding of four
dimensional into eleven dimensional supergravities. In four dimensions we get
two solutions: an asymptotic one corresponding to and a near horizon
fixed point solution of the form . Hence, while the former
solution has 32 supercharges the latter turns out to have only 4 conserved.
Moreover, we managed to find an exact interpolating solution, thus connecting
the above two. Aiming at a future study of duality for the theory at
hand we derived the Penrose limit of the four dimensional solutions.
Interestingly the pp-wave limit of the near horizon solution suggests itself as
being of the supernumerary supersymmetric type. In D=11 we exhibit the uplift
of the four dimensional solutions: one associated to and the
other to a foliation of , as well as their pp-wave
limits.Comment: 14 pages, LaTe
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