310 research outputs found
Multiple meanings of words in arithmetic textbooks
This paper discusses the differences among arithmetic textbooks and how this poses problems for hearing impaired children
Comparison of written and spoken language from deaf and hearing children at five age levels
This dissertation compares oral and written language development in hearing and deaf children. The study applies grammatical, lexical and syntactical measures to describe and analyze the differences in language development in groups of hearing and orally-taught hearing-impaired children and to relate these findings to chronological age
Communication Partner Training in Aphasia: A Critical Review
This presentation describes the procedures and results of a systematic review of the literature on communication partner training in aphasia. A search of thirteen databases resulted in 28 relevant articles published in English between 1975 and April, 2008. These included 8 group studies varying from randomized controlled trials to uncontrolled pre-post studies, 7 single-subject experimental designs, 5 qualitative research designs and 8 case studies. Studies were independently reviewed by two reviewers. Results revealed a wide range of quality scores. Most studies fell in the weaker AAN evidence strength classes. However, 3 studies met the criteria for Class I research
Aphasia Centers in North America: A Survey
Aphasia management has traditionally targeted language impairments. However, programs have begun to address other consequences of aphasia such as social isolation, well-being, or participation. One means of addressing these consequences is via an “aphasia center.” An online survey was developed and distributed in order to learn more about aphasia centers in North America. Thirty one respondents provided information (e.g. demographics, mission/goals, admission and discharge criteria, funding sources, programming). The data were analyzed via frequency counts and charts, as well as qualitatively by identifying key themes that helped to describe characteristics of aphasia centers
The Large-scale Distribution of Cool Gas around Luminous Red Galaxies
We present a measurement of the correlation function between luminous red
galaxies and cool gas traced by Mg II \lambda \lambda 2796, 2803 absorption, on
scales ranging from about 30 kpc to 20 Mpc. The measurement is based on
cross-correlating the positions of about one million red galaxies at z~0.5 and
the flux decrements induced in the spectra of about 10^5 background quasars
from the Sloan Digital Sky Survey. We find that: (i) This galaxy-gas
correlation reveals a change of slope on scales of about 1 Mpc, consistent with
the expected transition from a dark matter halo dominated environment to a
regime where clustering is dominated by halo-halo correlations. Assuming that,
on average, the distribution of Mg II gas follows that of dark matter up to a
gas-to-mass ratio, we find the standard halo model to provide an accurate
description of the gas distribution over three orders of magnitude in scale.
Within this framework we estimate the average host halo mass of luminous red
galaxies to be about 10^{13.5} M_solar, in agreement with other methods. We
also find the Mg II gas-to-mass ratio around LRGs to be consistent with the
cosmic value estimated on Mpc scales. Combining our galaxy-gas correlation and
the galaxy-mass correlation function from galaxy-galaxy lensing analyses we can
directly measure the Mg II gas-to-mass ratio as a function of scale and reach
the same conclusion. (ii) From line-width estimates, we show that the velocity
dispersion of the gas clouds also shows the expected 1- and 2-halo behaviors.
On large scales the gas distribution follows the Hubble flow, whereas on small
scales we observe the velocity dispersion of the Mg II gas clouds to be lower
than that of collisionless dark matter particles within their host halo. This
is in line with the fact that cool clouds are subject to the pressure of the
virialized hot gas.Comment: 18 pages, 11 figures, 1 table, submitted to MNRA
APOGEE Kinematics I: Overview of the Kinematics of the Galactic Bulge as Mapped by APOGEE
We present the stellar kinematics across the Galactic bulge and into the disk
at positive longitudes from the SDSS-III APOGEE spectroscopic survey of the
Milky Way. APOGEE includes extensive coverage of the stellar populations of the
bulge along the mid-plane and near-plane regions. From these data, we have
produced kinematic maps of 10,000 stars across longitudes 0 deg < l < 65 deg,
and primarily across latitudes of |b| < 5 deg in the bulge region. The APOGEE
data reveal that the bulge is cylindrically rotating across all latitudes and
is kinematically hottest at the very centre of the bulge, with the smallest
gradients in both kinematic and chemical space inside the inner-most region
(l,|b|) < (5,5) deg. The results from APOGEE show good agreement with data from
other surveys at higher latitudes and a remarkable similarity to the rotation
and dispersion maps of barred galaxies viewed edge on. The thin bar that is
reported to be present in the inner disk within a narrow latitude range of |b|
< 2 deg appears to have a corresponding signature in [Fe/H] and [alpha/Fe].
Stars with [Fe/H] > -0.5 have dispersion and rotation profiles that are similar
to that of N-body models of boxy/peanut bulges. There is a smooth kinematic
transition from the thin bar and boxy bulge (l,|b|) < (15,12) deg out into the
disk for stars with [Fe/H] > -1.0, and the chemodynamics across (l,b) suggests
the stars in the inner Galaxy with [Fe/H] > -1.0 have an origin in the disk.Comment: Accepted by ApJ 15 December 201
Preparing First-Time Leaders for an Urban Public School District: An Action Research Study of a Collaborative District-University Partnership
This article reports the results for the first cycle of an action research study about a district-university partnership. Two district facilitators and two university facilitators co-constructed a principal preparation program for an innercity school district to help prepare the next generation of building leaders. Twenty-two students participated in the 15-month nontraditional program. The study found that in preparing first-time school leaders, the most helpful experiences were those that developed self-understanding and readiness for the role change. New instructional techniques and the full-time residency facilitated this learning. It also found that the partnership, though providing new and exciting opportunities to deviate from the traditional preparation model, needed further development
The Sloan Digital Sky Survey Reverberation Mapping Project: Ensemble Spectroscopic Variability of Quasar Broad Emission Lines
We explore the variability of quasars in the MgII and Hbeta broad emission
lines and UV/optical continuum emission using the Sloan Digital Sky Survey
Reverberation Mapping project (SDSS-RM). This is the largest spectroscopic
study of quasar variability to date: our study includes 29 spectroscopic epochs
from SDSS-RM over months, containing 357 quasars with MgII and 41 quasars
with Hbeta . On longer timescales, the study is also supplemented with
two-epoch data from SDSS-I/II. The SDSS-I/II data include an additional
quasars with MgII and 572 quasars with Hbeta. The MgII emission line is
significantly variable ( 10% on 100-day timescales), a necessary
prerequisite for its use for reverberation mapping studies. The data also
confirm that continuum variability increases with timescale and decreases with
luminosity, and the continuum light curves are consistent with a damped
random-walk model on rest-frame timescales of days. We compare the
emission-line and continuum variability to investigate the structure of the
broad-line region. Broad-line variability shows a shallower increase with
timescale compared to the continuum emission, demonstrating that the broad-line
transfer function is not a -function. Hbeta is more variable than MgII
(roughly by a factor of ), suggesting different excitation mechanisms,
optical depths and/or geometrical configuration for each emission line. The
ensemble spectroscopic variability measurements enabled by the SDSS-RM project
have important consequences for future studies of reverberation mapping and
black hole mass estimation of quasars.Comment: 20 pages, 25 figures. ApJ accepted: minor revisions following referee
repor
High-resolution, H band Spectroscopy of Be Stars with SDSS-III/APOGEE: I. New Be Stars, Line Identifications, and Line Profiles
APOGEE has amassed the largest ever collection of multi-epoch,
high-resolution (R~22,500), H-band spectra for B-type emission line (Be) stars.
The 128/238 APOGEE Be stars for which emission had never previously been
reported serve to increase the total number of known Be stars by ~6%. We focus
on identification of the H-band lines and analysis of the emission peak
velocity separations (v_p) and emission peak intensity ratios (V/R) of the
usually double-peaked H I and non-hydrogen emission lines. H I Br11 emission is
found to preferentially form in the circumstellar disks at an average distance
of ~2.2 stellar radii. Increasing v_p toward the weaker Br12--Br20 lines
suggests these lines are formed interior to Br11. By contrast, the observed IR
Fe II emission lines present evidence of having significantly larger formation
radii; distinctive phase lags between IR Fe II and H I Brackett emission lines
further supports that these species arise from different radii in Be disks.
Several emission lines have been identified for the first time including
~16895, a prominent feature in the spectra for almost a fifth of the sample
and, as inferred from relatively large v_p compared to the Br11-Br20, a tracer
of the inner regions of Be disks. Unlike the typical metallic lines observed
for Be stars in the optical, the H-band metallic lines, such as Fe II 16878,
never exhibit any evidence of shell absorption, even when the H I lines are
clearly shell-dominated. The first known example of a quasi-triple-peaked Br11
line profile is reported for HD 253659, one of several stars exhibiting intra-
and/or extra-species V/R and radial velocity variation within individual
spectra. Br11 profiles are presented for all discussed stars, as are full
APOGEE spectra for a portion of the sample.Comment: accepted in A
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