866 research outputs found
Creativity and Pre-Service Teacher Education: What You See is What You Get
This essay discusses creativity in the classroom, constraints and the lack of creativity modeling in undergraduate teacher education programs, and some simple changes that can be made. This lack of models and modeling of creativity in the teacher education classrooms leads to a lack of creativity in teaching, activity design, tasks, and assessments. Issues related to lack of creativity in the education system are discussed from the student, faculty, state, and government levels. 
Relationship between Internal Consistency and Goodness of Fit Maximum Likelihood Factor Analysis with Varimax Rotation
This study investigates how reliability (internal consistency) affects model-fitting in maximum likelihood exploratory factor analysis (EFA). This was accomplished through an examination of goodness of fit indices between the population and the sample matrices. Monte Carlo simulations were performed to create pseudo-populations with known parameters. Results indicated that the higher the internal consistency the worse the fit. It is postulated that the observations are similar to those from structural equation modeling where a good fit with low correlations can be observed and also the reverse with higher item correlations
Knowledge is not everything: Analysis of children’s performance on a haptic comparison task
Abstract The relative effects of developmental level and domain-specific knowledge on children's ability to identify and make similarity decisions about object concepts based only on haptic (touch) information were investigated. Children aged 4-9 years with varying levels of dinosaur knowledge completed a cross-comparison task in which they haptically explored pairs of familiar (dinosaur) and unfamiliar (sea creature) models that varied in terms of their degree of differentiability. Older children explored models more exhaustively, found more differentiating features and consequently made fewer errors than younger children did. High knowledge enabled children to identify models correctly, but was also associated with the use of a hypothesis testing strategy, which led children to make greater numbers of ''miss'' errors on the cross-comparison task. Performance in the control domain illustrated that the hypothesis testing strategy was specific to the high knowledge domain. Potential explanations for the role of knowledge and development in haptic exploration are considered.
High star formation rates as the origin of turbulence in early and modern disk galaxies
High spatial and spectral resolution observations of star formation and
kinematics in early galaxies have shown that two-thirds are massive rotating
disk galaxies with the remainder being less massive non-rotating objects. The
line of sight averaged velocity dispersions are typically five times higher
than in today's disk galaxies. This has suggested that
gravitationally-unstable, gas-rich disks in the early Universe are fuelled by
cold, dense accreting gas flowing along cosmic filaments and penetrating hot
galactic gas halos. However these accreting flows have not been observed, and
cosmic accretion cannot power the observed level of turbulence. Here we report
on a new sample of rare high-velocity-dispersion disk galaxies we have
discovered in the nearby Universe where cold accretion is unlikely to drive
their high star-formation rates. We find that the velocity dispersion is most
fundamentally correlated with their star-formation rates, and not their mass
nor gas fraction, which leads to a new picture where star formation itself is
the energetic driver of galaxy disk turbulence at all cosmic epochs.Comment: 9 pages, 2 figures, Supplimentary Info available at:
http://pulsar.swin.edu.au/~agreen/nature/sigma_mean_arXiv.pdf. Accepted for
publication in Natur
On the frequency, intensity and duration of starburst episodes triggered by galaxy interactions and mergers
We investigate the intensity enhancement and the duration of starburst
episodes, triggered by major galaxy interactions and mergers. To this aim, we
analyze two large statistical datasets of numerical simulations. These have
been obtained using two independent and different numerical techniques to model
baryonic and dark matter evolution, that are extensively compared for the first
time. One is a Tree-SPH code, the other one is a grid-based N-body
sticky-particles code. We show that, at low redshift, galaxy interactions and
mergers in general trigger only moderate star formation enhancements. Strong
starbursts where the star formation rate is increased by a factor larger than 5
are rare and found only in about 15% of major galaxy interactions and mergers.
Merger-driven starbursts are also rather short-lived, with a typical duration
of the activity of a few 10^8 yr. These conclusions are found to be robust,
independent from the numerical techniques and star formation models. At higher
redshifts where galaxies contain more gas, gas inflow-induced starbursts are
neither stronger neither longer than their local counterparts. In turn, the
formation of massive gas clumps, results of local Jeans instability that can
occur spontaneously in gas-rich disks or be indirectly favored by galaxy
interactions, could play a more important role in determining the duration and
intensity of star formation episodes.Comment: 22 pages, 28 figures, A&A accepted. High resolution version available
at http://aramis.obspm.fr/~paola/SFR_frequency
SPIRE imaging of M82: cool dust in the wind and tidal streams
M82 is a unique representative of a whole class of galaxies, starbursts with
superwinds, in the Very Nearby Galaxy Survey with Herschel. In addition, its
interaction with the M81 group has stripped a significant portion of its
interstellar medium from its disk. SPIRE maps now afford better
characterization of the far-infrared emission from cool dust outside the disk,
and sketch a far more complete picture of its mass distribution and energetics
than previously possible. They show emission coincident in projection with the
starburst wind and in a large halo, much more extended than the PAH band
emission seen with Spitzer. Some complex substructures coincide with the
brightest PAH filaments, and others with tidal streams seen in atomic hydrogen.
We subtract the far-infrared emission of the starburst and underlying disk from
the maps, and derive spatially-resolved far-infrared colors for the wind and
halo. We interpret the results in terms of dust mass, dust temperature, and
global physical conditions. In particular, we examine variations in the dust
physical properties as a function of distance from the center and the wind
polar axis, and conclude that more than two thirds of the extraplanar dust has
been removed by tidal interaction, and not entrained by the starburst wind.Comment: accepted in A&A Herschel special issu
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