4,016 research outputs found
Developing communication and thinking skills in English as a Foreign Language Education undergraduate students: a proposal for a syllabus model
It is our aim to share a proposal for a new syllabus model and learner-centered methodology for English as a Foreign Language students in the Degree in Teaching in Primary Education at the Universidad de Zaragoza (Spain), presenting the theoretical tenets and analyzing samples of resources and materials that have been designed. In a context of great diversity of levels and learning profiles in the abovementioned educational setting, it is no longer valid to conceive this part of teacher training only in terms of language proficiency, but rather it is necessary to equip students with learning to learn tools and metacognitive strategies as well as materials and resources purposefully designed bearing in mind their context, professional interests and linguistic needs. As a result, throughout the three 6 ECTS courses in the Degree (English in Primary Education I, II and III, for ist, 2nd and 4th year students respectively) we seek to implement active methodologies and make use of a variety of resources following Communicative Language Teaching and Task-based Instruction principles, such as the following: (i) Deep Learning (Clark, 2009a, 2009b) and Scaffolded, Visible Thinking (Ritchhart, Church, and Morrison, 2011); (ii) Cooperative Learning (Kagan and Kagan, 1994); (iii) ICTs and EdTech; (iv) reflective learning, promoting self-assessment and peer-assessment, and (v) Project Based Learning (BIE, 2003). Overall, the teaching proposal designed has enabled us to partially respond to heterogeneity in our large classes and make our students'' learning of a language relevant and meaningful
The X-ray Luminosities of HH Objects
The recent detection of X-ray emission from HH 2 and HH 154 with the Chandra
and XMM-Newton satellites (respectively) have opened up an interesting, new
observational possibility in the field of Herbig-Haro objects. In order to be
able to plan further X-ray observations of other HH objects, it is now of
interest to be able to estimate their X-ray luminosities in order to choose
which objects to observe. This paper describes a simple, analytic model for
predicting the X-ray luminosity of a bow shock from the parameters of the flow
(i.e., the size of the bow shock, its velocity, and the pre-shock density). The
accuracy of the analytic model is analyzed through a comparison with the
predictions obtained from axisymmetric, gasdynamic simulations of the leading
working surface of an HH jet. We find that our analytic model reproduces the
observed X-ray luminosities of HH 2 and HH 154, and we propose that HH~80/81 is
a good candidate for future observations with Chandra.Comment: 10 pages (8 text, 2 figures
Self-energy correction to the hyperfine structure splitting of the 1s and 2s states in hydrogenlike ions
The one-loop self-energy correction to the hyperfine structure splitting of
the 1s and 2s states of hydrogenlike ions is calculated both for the point and
finite nucleus. The results of the calculation are combined with other
corrections to find the ground state hyperfine splitting in lithiumlike
^{209}Bi^{80+} and ^{165}Ho^{64+}.Comment: The table 2 is changed. 6 pages, 1 figure, Late
Electron Probe Microanalysis of the Otolithic Membrane. A Methodological and Quantitative Study
The effect of tissue preparation on calcium and potassium weight percents in the otoconial layer in the utricle and saccule was studied in four groups of OF1 mice with electron probe X-ray microanalysis. Glutaraldehyde and freeze-drying, glutaraldehyde and air-drying, air-drying, and cryo-fixation and freeze-drying were compared. Ca and K changed significantly in the utricle depending on the method used (P \u3c 0.001), and K changed significantly in the saccule (P \u3c 0.001 ). We chose cryo-fixation with freeze-drying for the quantitative analysis of the otolithic membrane because this method provided the highest values of Ca and K with minimum loss of Ca and K . Microcrystalline salt standards mounted on scanning electron microscopy holders were used for the quantification of Ca and K by the peak-to-local-background (P/B) ratio method. The P/B ratio in standards with reproducible results, when plotted against weight percent, gave a straight line for Ca (r = 0.99, P \u3c 0.001) and K (r = 0.98, P \u3c 0.001). The Ca and K weight percents in otoconia showed similar frequency distributions in the utricle and saccule
Modeling and predicting the shape of the far-infrared to submillimeter emission in ultra-compact HII regions and cold clumps
Dust properties are very likely affected by the environment in which dust
grains evolve. For instance, some analyses of cold clumps (7 K- 17 K) indicate
that the aggregation process is favored in dense environments. However,
studying warm (30 K-40 K) dust emission at long wavelength (300
m) has been limited because it is difficult to combine far
infared-to-millimeter (FIR-to-mm) spectral coverage and high angular resolution
for observations of warm dust grains. Using Herschel data from 70 to 500
m, which are part of the Herschel infrared Galactic (Hi-GAL) survey
combined with 1.1 mm data from the Bolocam Galactic Plane Survey (BGPS), we
compared emission in two types of environments: ultra-compact HII (UCHII)
regions, and cold molecular clumps (denoted as cold clumps). With this
comparison we tested dust emission models in the FIR-to-mm domain that
reproduce emission in the diffuse medium, in these two environments (UCHII
regions and cold clumps). We also investigated their ability to predict the
dust emission in our Galaxy. We determined the emission spectra in twelve UCHII
regions and twelve cold clumps, and derived the dust temperature (T) using the
recent two-level system (TLS) model with three sets of parameters and the
so-called T- (temperature-dust emissvity index) phenomenological models,
with set to 1.5, 2 and 2.5. We tested the applicability of the TLS
model in warm regions for the first time. This analysis indicates distinct
trends in the dust emission between cold and warm environments that are visible
through changes in the dust emissivity index. However, with the use of standard
parameters, the TLS model is able to reproduce the spectral behavior observed
in cold and warm regions, from the change of the dust temperature alone,
whereas a T- model requires to be known.Comment: Accepted for publication in A&A. 19 pages, 8 figures, 7 table
Solitary-wave Vortices in Quadratic Nonlinear Media
We find families of vortex solitary waves in bulk quadratic nonlinear media under conditions for second-harmonic generation. We show that the vortex solitary waves are azimuthally unstable and that they decay into sets of stable spatial solitons. We calculate the growth rates of the azimuthal perturbations and show how those affect the pattern of output light. © 1998 Optical Society of AmericaThis work has been partially supported by the Spanish Government under grant PB95-0768.Peer Reviewe
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A high-resolution transmission-type x-ray spectrometer designed for observation of the Kα transitions of highly charged high-Z ions
High-resolution reflection-type crystal spectrometers have been used for x-ray energies up to 13 keV, e.g., the K-shell radiation of heliumlike Kr. In order to extend crystal spectrometer measurements to higher energy x rays from higher-Z elements, we employ the crystal in transmission. The geometry we use is known as DuMond geometry. Using such a transmission-type crystal x-ray spectrometer, we have measured the K-shell radiation of various highly charged high-Z ions. In particular, we present a measurement of the 1s2p 1P1→1s2 1S0 transition in heliumlike xenon, Xe52+. For this transition, we measure a linewidth of 34 eV, which demonstrates that the resolving power we achieved with the new spectrometer is on the order of 100
Instabilities of Higher-Order Parametric Solitons. Filamentation versus Coalescence
We investigate stability and dynamics of higher-order solitary waves in
quadratic media, which have a central peak and one or more surrounding rings.
We show existence of two qualitatively different behaviours. For positive phase
mismatch the rings break up into filaments which move radially to initial ring.
For sufficient negative mismatches rings are found to coalesce with central
peak, forming a single oscillating filament.Comment: 5 pages, 7 figure
Scanning microscopies of superconductors at very low temperatures
We discuss basics of scanning tunneling microscopy and spectroscopy (STM/S)
of the superconducting state with normal and superconducting tips. We present a
new method to measure the local variations in the Andreev reflection amplitude
between a superconducting tip and the sample. This method is termed Scanning
Andreev Reflection Spectroscopy (SAS). We also briefly discuss vortex imaging
with STM/S under an applied current through the sample, and show the vortex
lattice as a function of the angle between the magnetic field and sample's
surface
Mechanical-alloying and lattice distortions in ball-milled CuFe
A least-square fitting analysis of EXAFS data collected from partially-crystallized Fe_80B_20 thin films (t=15 nm), using data collected from pure phase standards of the crystallization products, was found effective in determining the relative atomic fraction of each crystalline phase present. This fitting scheme provides a means for the quantitative treatment of crystallization and precipitation kinetics in thin films and multilayered structures
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