1,556 research outputs found
Teachers\u27 Attitudes Toward the Inclusion of Students with Disabilities in the General Education Classroom in a Rural School District
According to the research, inclusion in the general education setting is valuable to the academic and social development of students with disabilities. Teachers play a significant role in the success of students with disabilities in this setting (Coombs-Richardson & Mead, 2001; Fuchs, 2010; Test et al., 2009). Research shows that teachers display positive and negative attitudes toward inclusion based on the severity of the disability category (Cook, 2001; Ernest & Rogers, 2009). The purpose of this study was to examine teachers’ attitudes toward the inclusion of students with disabilities in the general education classroom in a rural school district. An ANOVA was run to analyze teachers’ attitudes based on disability category and to determine if grade level taught by teachers acts as a moderator to their attitudes. Results revealed that students’ disability categories had a significant impact on teachers’ attitudes and that grade level taught acts as a moderator to teachers’ attitudes toward inclusion. Limitations were discussed, and recommendations for practice, policy, and research were provided
Kinematic frames and "active longitudes": does the Sun have a face?
It has recently been claimed that analysis of Greenwich sunspot data over 120
years reveals that sunspot activity clusters around two longitudes separated by
180 degrees (``active longitudes'') with clearly defined differential rotation
during activity cycles.In the present work we extend this critical examination
of methodology to the actual Greenwich sunspot data and also consider newly
proposed methods of analysis claiming to confirm the original identification of
active longitudes. Our analysis revealed that values obtained for the
parameters of differential rotation are not stable across different methods of
analysis proposed to track persistent active longitudes. Also, despite a very
thorough search in parameter space, we were unable to reproduce results
claiming to reveal the century-persistent active longitudes. We can therefore
say that strong and well substantiated evidence for an essential and
century-scale persistent nonaxisymmetry in the sunspot distribution does not
exist.Comment: 14 pages, 1 table, 21 figures, accepted in A&
Alignment of galaxies relative to their local environment in SDSS-DR8
We study the alignment of galaxies relative to their local environment in
SDSS-DR8 and, using these data, we discuss evolution scenarios for different
types of galaxies. We defined a vector field of the direction of anisotropy of
the local environment of galaxies. We summed the unit direction vectors of all
close neighbours of a given galaxy in a particular way to estimate this field.
We found the alignment angles between the spin axes of disc galaxies, or the
minor axes of elliptical galaxies, and the direction of anisotropy. The
distributions of cosines of these angles are compared to the random
distributions to analyse the alignment of galaxies. Sab galaxies show
perpendicular alignment relative to the direction of anisotropy in a sparse
environment, for single galaxies and galaxies of low luminosity. Most of the
parallel alignment of Scd galaxies comes from dense regions, from 2...3 member
groups and from galaxies with low luminosity. The perpendicular alignment of S0
galaxies does not depend strongly on environmental density nor luminosity; it
is detected for single and 2...3 member group galaxies, and for main galaxies
of 4...10 member groups. The perpendicular alignment of elliptical galaxies is
clearly detected for single galaxies and for members of < 11 member groups; the
alignment increases with environmental density and luminosity. We confirm the
existence of fossil tidally induced alignment of Sab galaxies at low z. The
alignment of Scd galaxies can be explained via the infall of matter to
filaments. S0 galaxies may have encountered relatively massive mergers along
the direction of anisotropy. Major mergers along this direction can explain the
alignment of elliptical galaxies. Less massive, but repeated mergers are
possibly responsible for the formation of elliptical galaxies in sparser areas
and for less luminous elliptical galaxies.Comment: 15 pages, 15 figures, accepted for publication in A&
Characterizing neuromorphologic alterations with additive shape functionals
The complexity of a neuronal cell shape is known to be related to its
function. Specifically, among other indicators, a decreased complexity in the
dendritic trees of cortical pyramidal neurons has been associated with mental
retardation. In this paper we develop a procedure to address the
characterization of morphological changes induced in cultured neurons by
over-expressing a gene involved in mental retardation. Measures associated with
the multiscale connectivity, an additive image functional, are found to give a
reasonable separation criterion between two categories of cells. One category
consists of a control group and two transfected groups of neurons, and the
other, a class of cat ganglionary cells. The reported framework also identified
a trend towards lower complexity in one of the transfected groups. Such results
establish the suggested measures as an effective descriptors of cell shape
Hotspot Zuidplaspolder: Climate adaptation in the Zuidplaspolder
Building at the lowest point in the Netherlands, in the Zuidplaspolder, is viewed as a challenge and not something that is impossible. The Xplorelab approach in the Hotspot Zuidplaspolder project is a combination of research, implementation of ideas into inspiring examples and evaluation
The Variability of Sagittarius A* at Centimeter Wavelengths
We present the results of a 3.3-year project to monitor the flux density of
Sagittarius A* at 2.0, 1.3, and 0.7 cm with the VLA. The fully calibrated light
curves for Sgr A* at all three wavelengths are presented. Typical errors in the
flux density are 6.1%, 6.2%, and 9.2% at 2.0, 1.3, and 0.7 cm, respectively.
There is preliminary evidence for a bimodal distribution of flux densities,
which may indicate the existence of two distinct states of accretion onto the
supermassive black hole. At 1.3 and 0.7 cm, there is a tail in the distribution
towards high flux densities. Significant variability is detected at all three
wavelengths, with the largest amplitude variations occurring at 0.7 cm. The rms
deviation of the flux density of Sgr A* is 0.13, 0.16, and 0.21 Jy at 2.0, 1.3,
and 0.7 cm, respectively. During much of this monitoring campaign, Sgr A*
appeared to be relatively quiescent compared to results from previous
campaigns. At no point during the monitoring campaign did the flux density of
Sgr A* more than double its mean value. The mean spectral index of Sgr A* is
alpha=0.20+/-0.01, with a standard deviation of 0.14. The spectral index
appears to depend linearly on the observed flux density at 0.7 cm with a
steeper index observed during outbursts. This correlation is consistent with
the expectation for outbursts that are self-absorbed at wavelengths of 0.7 cm
or longer and inconsistent with the effects of simple models for interstellar
scintillation. Much of the variability of Sgr A*, including possible time lags
between flux density changes at the different wavelengths, appears to occur on
time scales less than the time resolution of our observations (8 days). Future
observations should focus on the evolution of the flux density on these time
scales.Comment: 16 pages, 10 figures, accepted for publication in A
The Flatness of Bifurcations in 3D Dendritic Trees: An Optimal Design
The geometry of natural branching systems generally reflects functional optimization. A common property is that their bifurcations are planar and that daughter segments do not turn back in the direction of the parent segment. The present study investigates whether this also applies to bifurcations in 3D dendritic arborizations. This question was earlier addressed in a first study of flatness of 3D dendritic bifurcations by Uylings and Smit (1975), who used the apex angle of the right circular cone as flatness measure. The present study was inspired by recent renewed interest in this measure. Because we encountered ourselves shortcomings of this cone angle measure, the search for an optimal measure for flatness of 3D bifurcation was the second aim of our study. Therefore, a number of measures has been developed in order to quantify flatness and orientation properties of spatial bifurcations. All these measures have been expressed mathematically in terms of the three bifurcation angles between the three pairs of segments in the bifurcation. The flatness measures have been applied and evaluated to bifurcations in rat cortical pyramidal cell basal and apical dendritic trees, and to random spatial bifurcations. Dendritic and random bifurcations show significant different flatness measure distributions, supporting the conclusion that dendritic bifurcations are significantly more flat than random bifurcations. Basal dendritic bifurcations also show the property that their parent segments are generally aligned oppositely to the bisector of the angle between their daughter segments, resulting in “symmetrical” configurations. Such geometries may arise when during neuronal development the segments at a newly formed bifurcation are subjected to elastic tensions, which force the bifurcation into an equilibrium planar shape. Apical bifurcations, however, have parent segments oppositely aligned with one of the daughter segments. These geometries arise in the case of side branching from an existing apical main stem. The aligned “apical” parent and “apical” daughter segment form together with the side branch daughter segment already geometrically a flat configuration. These properties are clearly reflected in the flatness measure distributions. Comparison of the different flatness measures made clear that they all capture flatness properties in a different way. Selection of the most appropriate measure thus depends on the question of research. For our purpose of quantifying flatness and orientation of the segments, the dihedral angle β was found to be the most discriminative and applicable single measure. Alternatively, the parent elevation and azimuth angle formed an orthogonal pair of measures most clearly demonstrating the dendritic bifurcation “symmetry” properties
- …