1,859 research outputs found
Power Spectrum Analysis of Polarized Emission from the Canadian Galactic Plane Survey
Angular power spectra are calculated and presented for the entirety of the
Canadian Galactic Plane Survey polarization dataset at 1.4 GHz covering an area
of 1060 deg. The data analyzed are a combination of data from the 100-m
Effelsberg Telescope, the 26-m Telescope at the Dominion Radio Astrophysical
Observatory, and the Synthesis Telescope at the Dominion Radio Astrophysical
Observatory, allowing all scales to be sampled down to arcminute resolution.
The resulting power spectra cover multipoles from to and display both a power-law component at low multipoles and a
flattening at high multipoles from point sources. We fit the power spectrum
with a model that accounts for these components and instrumental effects. The
resulting power-law indices are found to have a mode of 2.3, similar to
previous results. However, there are significant regional variations in the
index, defying attempts to characterize the emission with a single value. The
power-law index is found to increase away from the Galactic plane. A transition
from small-scale to large-scale structure is evident at ,
associated with the disk-halo transition in a 15 region around
. Localized variations in the index are found toward HII regions
and supernova remnants, but the interpretation of these variations is
inconclusive. The power in the polarized emission is anticorrelated with bright
thermal emission (traced by H emission) indicating that the thermal
emission depolarizes background synchrotron emission.Comment: Accepted to ApJ; 17 page
The structured environments of embedded star-forming cores. PACS and SPIRE mapping of the enigmatic outflow source UYSO 1
The intermediate-mass star-forming core UYSO 1 has previously been found to
exhibit intriguing features. While deeply embedded and previously only
identified by means of its (sub-)millimeter emission, it drives two powerful,
dynamically young, molecular outflows. Although the process of star formation
has obviously started, the chemical composition is still pristine. We present
Herschel PACS and SPIRE continuum data of this presumably very young region.
The now complete coverage of the spectral energy peak allows us to precisely
constrain the elevated temperature of 26 - 28 K for the main bulge of gas
associated with UYSO1, which is located at the interface between the hot HII
region Sh 2-297 and the cold dark nebula LDN 1657A. Furthermore, the data
identify cooler compact far-infrared sources of just a few solar masses, hidden
in this neighbouring dark cloud.Comment: accepted contribution for the forthcoming Herschel Special Issue of
A&A, 5 pages (will appear as 4-page letter in the journal), 6 figure file
Dust-temperature of an isolated star-forming cloud: Herschel observations of the Bok globule CB244
We present Herschel observations of the isolated, low-mass star-forming Bok
globule CB244. It contains two cold sources, a low-mass Class 0 protostar and a
starless core, which is likely to be prestellar in nature, separated by 90
arcsec (~ 18000 AU). The Herschel data sample the peak of the Planck spectrum
for these sources, and are therefore ideal for dust-temperature and column
density modeling. With these data and a near-IR extinction map, the MIPS 70
micron mosaic, the SCUBA 850 micron map, and the IRAM 1.3 mm map, we model the
dust-temperature and column density of CB244 and present the first measured
dust-temperature map of an entire star-forming molecular cloud. We find that
the column-averaged dust-temperature near the protostar is ~ 17.7 K, while for
the starless core it is ~ 10.6K, and that the effect of external heating causes
the cloud dust-temperature to rise to ~ 17 K where the hydrogen column density
drops below 10^21 cm^-2. The total hydrogen mass of CB244 (assuming a distance
of 200 pc) is 15 +/- 5 M_sun. The mass of the protostellar core is 1.6 +/- 0.1
M_sun and the mass of the starless core is 5 +/- 2 M_sun, indicating that ~ 45%
of the mass in the globule is participating in the star-formation process.Comment: Accepted for A&A Herschel Special Issue; 5 pages, 2 figure
A knowledge-based expert system for scheduling of airborne astronomical observations
The Kuiper Airborne Observatory Scheduler (KAOS) is a knowledge-based expert system developed at NASA Ames Research Center to assist in route planning of a C-141 flying astronomical observatory. This program determines a sequence of flight legs that enables sequential observations of a set of heavenly bodies derived from a list of desirable objects. The possible flight legs are constrained by problems of observability, avoiding flyovers of warning and restricted military zones, and running out of fuel. A significant contribution of the KAOS program is that it couples computational capability with a reasoning system
Modeling chemistry in and above snow at Summit, Greenland – Part 1: Model description and results
Sun-lit snow is increasingly recognized as a chemical reactor that plays an active role in uptake, transformation, and release of atmospheric trace gases. Snow is known to influence boundary layer air on a local scale, and given the large global surface coverage of snow may also be significant on regional and global scales. We present a new detailed one-dimensional snow chemistry module that has been coupled to the 1-D atmospheric boundary layer model MISTRA. The new 1-D snow module, which is dynamically coupled to the overlaying atmospheric model, includes heat transport in the snowpack, molecular diffusion, and wind pumping of gases in the interstitial air. The model includes gas phase chemical reactions both in the interstitial air and the atmosphere. Heterogeneous and multiphase chemistry on atmospheric aerosol is considered explicitly. The chemical interaction of interstitial air with snow grains is simulated assuming chemistry in a liquid-like layer (LLL) on the grain surface. The coupled model, referred to as MISTRA-SNOW, was used to investigate snow as the source of nitrogen oxides (NOx) and gas phase reactive bromine in the atmospheric boundary layer in the remote snow covered Arctic (over the Greenland ice sheet) as well as to investigate the link between halogen cycling and ozone depletion that has been observed in interstitial air. The model is validated using data taken 10 June–13 June, 2008 as part of the Greenland Summit Halogen-HOx experiment (GSHOX). The model predicts that reactions involving bromide and nitrate impurities in the surface snow can sustain atmospheric NO and BrO mixing ratios measured at Summit, Greenland during this period
Integration of Sexuality Content into an Occupational Therapy Curriculum
Sexuality is a broad term that can be used to encompass other terms such as sexual expression and sexual functioning, and can be defined as a holistic concept of the individual that is more than just physical sexual behavior but also relates to thoughts and feelings of everyday life (Couldrick, 1998a). Sexuality and sexual functioning are considered an activity of daily living (ADL) by the Occupational Therapy Practice Framework: Domain and Process (2008); however, it is a topic that is not being routinely addressed with clients by occupational therapists or other healthcare professionals (Hattjar, 2012). Studies show there is a significant lack of information given to clients in regard to sexuality, as well as dissatisfaction with the services that are provided for sexuality. This information implies an increase in knowledge, experience, and comfort levels with sexuality needs to be addressed with occupational therapists and occupational therapy students in order to treat clients in a holistic and client-centered manner.
A comprehensive literature review was completed to identify key aspects of sexuality. The literature review revealed a significant lack in student and practitioner confidence and competence in addressing sexuality in a clinical setting. After an extensive search regarding the topic of sexuality within the profession of occupational therapy it was found that much of the limited literature stems from the late 1980’s to early 1990’s, yet the literature from the 2000’s continue to address the same issues. Due to the reported low levels of comfort for occupational therapy students and practitioners regarding sexuality and the role occupational therapists play in addressing the subject with clients, the following product was developed. There was a dearth of the information and no evidenced-based articles were located regarding sexuality or how to teach about the topic.
The product created includes lesson plans that address different aspects of physical and/or psychosocial impairments that may impact sexuality. The product lesson plans consist of varying lectures, readings and activities, to be incorporated into several courses throughout the duration of an occupational therapy professional program. The goal of this product is to increase exposure to issues of sexuality and sexual functioning throughout the curricula of a Midwestern professional occupational therapy program in order to create competent and comfortable practitioners within the field
Fast deuterium fractionation in magnetized and turbulent filaments
Deuterium fractionation is considered as an important process to infer the
chemical ages of prestellar cores in filaments. We present here the first
magneto-hydrodynamical simulations including a chemical network to study
deuterium fractionation in magnetized and turbulent filaments and their
substructures. The filaments typically show widespread deuterium fractionation
with average values . For individual cores of similar age, we
observe the deuteration fraction to increase with time, but also to be
independent of their average properties such as density, virial or
mass-to-magnetic flux ratio. We further find a correlation of the deuteration
fraction with core mass, average H density and virial parameter only at
late evolutionary stages of the filament and attribute this to the lifetime of
the individual cores. Specifically, chemically old cores reveal higher
deuteration fractions. Within the radial profiles of selected cores, we notice
differences in the structure of the deuteration fraction or surface density,
which we can attribute to their different turbulent properties. High
deuteration fractions of the order may be reached within
approximately ~kyrs, corresponding to two free-fall times, as defined for
cylindrical systems, of the filamentsComment: submitted to MNRAS. Comments welcom
Anomaluos RR Lyrae (V-I)_0 colors in Baade's Window
We compare (V-I)_0-(V-K)_0 color-color and (V-I)_0-log P period-color
diagrams for Baade's Window and local RRab Lyrae stars. We find that for a
fixed log P the Baade's Window RR Lyrae stars are ~0.17 magnitudes redder in
(V-I)_0 than the local RR Lyrae stars. We also show that there is no such
effect observed in (V-K)_0. We argue that an extinction misestimate towards
Baade's Window is not a plausible explanation of the discrepancy. Unlike
Baade's Window RR Lyrae stars, the local ones follow a black-body color-color
relation and are well approximated by theoretical models. We test two
parameters, metallicity and surface gravity, and find that their effects are
too small to explain the (V-I)_0 discrepancy between the two groups of stars.
We do not provide any explanation for the anomalous (V-I)_0 behavior of the
Baade's Window RR Lyrae stars. We note that a similar effect for clump giant
stars has been recently reported by Paczynski and we caution that RR Lyrae
stars and clump giants, often used as standard candles, can be subject to the
same type of systematics.Comment: 10 pages, 7 figures, submitted to Ap
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