58,941 research outputs found
Emerging trends on the topic of Information Technology in the field of Educational Sciences: a bibliometric exploration
The paper presents a bibliometric analysis on the topic of Information
Technology (IT) in the field of Educational Sciences, aimed at envisioning the
research emerging trends. The ERIC data base is used as a consultation source;
the results were subjected to productivity by authors, journals, and term
co-occurrence analysis indicators for the period 2009-2013. The productivity of
Computers & Education, and Turkish Online Journal of Educational
Technology-TOJET, as well as the preceding authors from Canada, have been
emphasized. The more used terms are the following: Information technology,
foreign countries, educational technology, technology integration, and student
attitudes. Researches performed here seem to have a largely qualitative
character, highlighting computers and internet as the mostly explored
technological objects. The largest subject matter trend refers to the
integration of IT in the higher education learning context, and its incidence
over the teaching methods
High-resolution imaging spectroscopy of two micro-pores and an arch filament system in a small emerging-flux region
Aims. The purpose of this investigation is to characterize the temporal
evolution of an emerging flux region, the associated photospheric and
chromospheric flow fields, and the properties of the accompanying arch filament
system. Methods. This study is based on imaging spectroscopy with the
G\"ottingen Fabry-P\'erot Interferometer at the Vacuum Tower Telescope, on 2008
August 7. Cloud model (CM) inversions of line scans in the strong chromospheric
absorption H line yielded CM parameters, which describe the cool plasma
contained in the arch filament system. Results. The observations cover the
decay and convergence of two micro-pores with diameters of less than one
arcsecond and provide decay rates for intensity and area. The photospheric
horizontal flow speed is suppressed near the two micro-pores indicating that
the magnetic field is sufficiently strong to affect the convective energy
transport. The micro-pores are accompanied by an arch filament system, where
small-scale loops connect two regions with H line-core brightenings
containing an emerging flux region with opposite polarities. The chromospheric
velocity of the cloud material is predominantly directed downwards near the
footpoints of the loops with velocities of up to 12 km/s, whereas loop tops
show upward motions of about 3 km/s. Conclusions. Micro-pores are the smallest
magnetic field concentrations leaving a photometric signature in the
photosphere. In the observed case, they are accompanied by a miniature arch
filament system indicative of newly emerging flux in the form of
-loops. Flux emergence and decay take place on a time-scale of about
two days, whereas the photometric decay of the micro-pores is much more rapid
(a few hours), which is consistent with the incipient submergence of
-loops. The results are representative for the smallest emerging flux
regions still recognizable as such.Comment: 15 pages, 16 figures, 3 tables, published in A&
Marginal Fermi liquid behavior from 2d Coulomb interaction
A full, nonperturbative renormalization group analysis of interacting
electrons in a graphite layer is performed, in order to investigate the
deviations from Fermi liquid theory that have been observed in the experimental
measures of a linear quasiparticle decay rate in graphite. The electrons are
coupled through Coulomb interactions, which remain unscreened due to the
semimetallic character of the layer. We show that the model flows towards the
noninteracting fixed-point for the whole range of couplings, with logarithmic
corrections which signal the marginal character of the interaction separating
Fermi liquid and non-Fermi liquid regimes.Comment: 7 pages, 2 Postscript figure
Stable gauged maps
We give an introduction to moduli stacks of gauged maps satisfying a
stability conditition introduced by Mundet and Schmitt, and the associated
integrals giving rise to gauged Gromov-Witten invariants. We survey various
applications to cohomological and K-theoretic Gromov-Witten invariants.Comment: Survey for the 2015 AMS Summer Institute on Algebraic Geometry. Split
off from the more technical paper "Properness for scaled gauged maps"
[arXiv:1606.01383]. There is still substantial overlap between the two
papers. This version has minor correction
Decays of polarized top quarks to lepton, neutrino and jets at NLO QCD
We compute the differential and total rate of the semileptonic decay of
polarized top-quarks at
next-to-leading order (NLO) in the QCD coupling with an off-shell intermediate
boson. We present several normalized distributions, in particular those
that reflect the -spin analyzing powers of the lepton, the b-jet and the
boson at LO and NLO QCD.Comment: Latex, 22 page
On the competitive effects of divisionalization
In this paper, we assume that firms can create independent divisions which compete in
quantities in a homogeneous good market. Assuming identical firms and constant returns to scale, we prove that the strategic interaction of firms yields Perfect Competition if the number of firms is
beyond some critical level. Assuming a fixed cost per firm and an upper bound on the maximum number of divisions, we show that when this upper bound tends to infinity and the fixed cost tends to zero, market equilibrium may yield either Perfect Competition or a Natural Oligopoly.Publicad
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