624 research outputs found
El Arte como Medio para Facilitar el Bilingüismo y Biculturalismo: Sugerencias desde una Revisión de la Literatura
This review of the literature critically explores the avenues to learning that visual art offers teachers and especially those with second language learners in their classrooms. The article is divided into seven sections in which the authors present research findings supporting the premise that learners’ cognitive processes are facilitated by images. Research cited strongly suggests visual art in instructional design helps students learn about world cultures, is an effective pre-writing activity, facilitates second language acquisition, and promotes biliteracy.Esta revisión de la literatura explora crÃticamente los caminos al aprendizaje que el arte visual provee a los maestros, especialmente a los que tienen estudiantes que están aprendiendo un segundo idioma en sus aulas. El artÃculo está dividido en siete secciones, en las cuales el autor presenta resultados de investigaciones previas que apoyan la premisa de que las imágenes visuales facilitan los procesos cognitivos de los estudiantes. Las investigaciones citadas indican claramente que a los estudiantes les beneficia dibujar e involucrarse en actividades visuales antes de redactar, lo cual facilita la adquisición de un segundo idioma y promueve la alfabetización en la primera y segunda lengua
Fluid-rock interaction during high-grade metamorphism: instructive examples from the Southern Marginal Zone of the Limpopo Complex, South Africa
The Southern Marginal Zone of the Limpopo Complex documents strong evidence that CO2-rich (XCO2=0.7–0.9, XH2O= 0.1–0.3) and brine fluids of greatly reduced water activity interacted with cooling metapelitic granulite during the thrust-controlled emplacement at 2.69–2.62 Ga onto the granite-greenstone terrain of the northern Kaapvaal Craton. Interaction of cooling metapelitic granulite with CO2-rich fluids at T 900°C, P > 7.5 kbar. Interaction of hot melt with metapelitic granulite continued until final emplacement in the middle crust (P = 6 kbar, T = 630°C). Brine fluids also initiated shear zone-hosted metasomatism of quartzo-feldspathic gneisses at T between 600 and 900°C and amphibolite-facies lode-gold mineralization. Available data implicate devolatilization of underthrusted greenstone material as the dominant deep crustal source for infiltrating CO2-rich and brine fluids
A Method to Determine the In-Air Spatial Spread of Clinical Electron Beams
We propose and analyze in detail a method to measure the in-air spatial
spread parameter of clinical electron beams. Measurements are performed at the
center of the beam and below the adjustable collimators sited in asymmetrical
configuration in order to avoid the distortions due to the presence of the
applicator. The main advantage of our procedure lies in the fact that the dose
profiles are fitted by means of a function which includes, additionally to the
Gaussian step usually considered, a background which takes care of the dose
produced by different mechanisms that the Gaussian model does not account for.
As a result, the spatial spread is obtained directly from the fitting procedure
and the accuracy permits a good determination of the angular spread. The way
the analysis is done is alternative to that followed by the usual methods based
on the evaluation of the penumbra width. Besides, the spatial spread found
shows the quadratic-cubic dependence with the distance to the source predicted
by the Fermi-Eyges theory. However, the corresponding values obtained for the
scattering power are differing from those quoted by ICRU nr. 35 by a factor ~2
or larger, what requires of a more detailed investigation.Comment: 11 pages, 5 Postscript figures, to be published in Medical Physic
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Alterations in Brain-Derived Neurotrophic Factor in the Mouse Hippocampus Following Acute but Not Repeated Benzodiazepine Treatment
Benzodiazepines (BZs) are safe drugs for treating anxiety, sleep, and seizure disorders, but their use also results in unwanted effects including memory impairment, abuse, and dependence. The present study aimed to reveal the molecular mechanisms that may contribute to the effects of BZs in the hippocampus (HIP), an area involved in drug-related plasticity, by investigating the regulation of immediate early genes following BZ administration. Previous studies have demonstrated that both brain derived neurotrophic factor (BDNF) and c-Fos contribute to memory- and abuse-related processes that occur within the HIP, and their expression is altered in response to BZ exposure. In the current study, mice received acute or repeated administration of BZs and HIP tissue was analyzed for alterations in BDNF and c-Fos expression. Although no significant changes in BDNF or c-Fos were observed in response to twice-daily intraperitoneal (i.p.) injections of diazepam (10 mg/kg + 5 mg/kg) or zolpidem (ZP; 2.5 mg/kg + 2.5 mg/kg), acute i.p. administration of both triazolam (0.03 mg/kg) and ZP (1.0 mg/kg) decreased BDNF protein levels within the HIP relative to vehicle, without any effect on c-Fos. ZP specifically reduced exon IV-containing BDNF transcripts with a concomitant increase in the association of methyl-CpG binding protein 2 (MeCP2) with BDNF promoter IV, suggesting that MeCP2 activity at this promoter may represent a ZP-specific mechanism for reducing BDNF expression. ZP also increased the association of phosphorylated cAMP response element binding protein (pCREB) with BDNF promoter I. Future work should examine the interaction between ZP and DNA as the cause for altered gene expression in the HIP, given that BZs can enter the nucleus and intercalate into DNA directly
Deformation effects in the Si+C and Si+Si reaction Search
The possible occurence of highly deformed configurations is investigated in
the Ca and Ni di-nuclear systems as formed in the
Si+C,Si reactions by using the properties of emitted light
charged particles. Inclusive as well as exclusive data of the heavy fragments
and their associated light charged particles have been collected by using the
{\sc ICARE} charged particle multidetector array. The data are analysed by
Monte Carlo CASCADE statistical-model calculations using a consistent set of
parameters with spin-dependent level densities. Significant deformation effects
at high spin are observed as well as an unexpected large Be cluster
emission of a binary nature.Comment: 3 pages latex, 2 eps figures, paper presented in "wokshop on physics
with multidetector array (pmda2000)Calcutta, India (to be published at
PRAMANA, journal of Physics, India
Deformation effects in Ni nuclei produced in Si+Si at 112 MeV
Velocity and energy spectra of the light charged particles (protons and
-particles) emitted in the Si(E = 112 MeV) + Si
reaction have been measured at the Strasbourg VIVITRON Tandem facility. The
ICARE charged particle multidetector array was used to obtain exclusive spectra
of the light particles in the angular range 15 - 150 degree and to determine
the angular correlations of these particles with respect to the emission angles
of the evaporation residues. The experimental data are analysed in the
framework of the statistical model. The exclusive energy spectra of
-particles emitted from the Si + Si compound system are
generally well reproduced by Monte Carlo calculations using spin-dependent
level densities. This spin dependence approach suggests the onset of large
deformations at high spin. A re-analysis of previous -particle data
from the Si + Si compound system, using the same spin-dependent
parametrization, is also presented in the framework of a general discussion of
the occurrence of large deformation effects in the A ~ 60 mass region.Comment: 25 pages, 6 figure
Highly deformed Ca configurations in Si + C
The possible occurrence of highly deformed configurations in the Ca
di-nuclear system formed in the Si + C reaction is investigated
by analyzing the spectra of emitted light charged particles. Both inclusive and
exclusive measurements of the heavy fragments (A 10) and their
associated light charged particles (protons and particles) have been
made at the IReS Strasbourg {\sc VIVITRON} Tandem facility at bombarding
energies of Si) = 112 MeV and 180 MeV by using the {\sc ICARE}
charged particle multidetector array. The energy spectra, velocity
distributions, and both in-plane and out-of-plane angular correlations of light
charged particles are compared to statistical-model calculations using a
consistent set of parameters with spin-dependent level densities. The analysis
suggests the onset of large nuclear deformation in Ca at high spin.Comment: 33 pages, 11 figure
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State-of-the-art software for window energy-efficiency rating and labeling
Measuring the thermal performance of windows in typical residential buildings is an expensive proposition. Not only is laboratory testing expensive, but each window manufacturer typically offers hundreds of individual products, each of which has different thermal performance properties. With over a thousand window manufacturers nationally, a testing-based rating system would be prohibitively expensive to the industry and to consumers. Beginning in the early 1990s, simulation software began to be used as part of a national program for rating window U-values. The rating program has since been expanded to include Solar Hear Gain Coefficients and is now being extended to annual energy performance. This paper describes four software packages available to the public from Lawrence Berkeley National Laboratory (LBNL). These software packages are used to evaluate window thermal performance: RESFEN (for evaluating annual energy costs), WINDOW (for calculating a product`s thermal performance properties), THERM (a preprocessor for WINDOW that determines two-dimensional heat-transfer effects), and Optics (a preprocessor for WINDOW`s glass database). Software not only offers a less expensive means than testing to evaluate window performance, it can also be used during the design process to help manufacturers produce windows that will meet target specifications. In addition, software can show small improvements in window performance that might not be detected in actual testing because of large uncertainties in test procedures
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