151 research outputs found
Targeted deep surveys of high Galactic latitude HI with the GBT
Over 800 sq. deg. of high Galactic latitude sky have been mapped at 21 cm
with the Robert C. Byrd Green Bank Telescope (GBT). An improved knowledge of
the telescope's beam characteristics has allowed us to reliably map not only
regions of high column density, but also such regions as ELAIS N1, a targeted
Spitzer field, which have very low HI column density. The additional fields we
have observed cover a cross-section of dynamically and chemically interesting
regions as indicated by the presence of intermediate/high velocity gas and/or
anomalous far-IR (dust) colour.Comment: 7 pages, 5 figures. To appear in "The Dynamic ISM: A celebration of
the Canadian Galactic Plane Survey" ASP Conference Serie
The Transmission of Shocks to the Chinese Economy in a Global Context: A Model-Based Approach
To better understand the dynamics of the Chinese economy and its interaction with the global economy, the authors incorporate China into an existing model for the G-3 economies (i.e., the United States, the euro area, and Japan), paying particular attention to modelling the exchange rate and monetary policy in China. Their findings suggest that the Chinese economy adjusts more slowly to shocks, compared to the large advanced economies, because monetary policy is less effective and the real exchange rate more persistent. In addition, the authors’ model underscores the importance of spillovers from China to the G-3 economies, and vice versa, thus highlighting the need to analyze the Chinese economy in a global context.Economic models; International topics; Business fluctuations and cycles; Exchange rate regimes
Experiences of Middle School Children With Autism Spectrum Disorders in Adapted Physical Education
School-age children with autism spectrum disorders (ASDs) are rarely asked to describe their experiences within the programs that they receive and are largely missing from the narrative of their own lives. Adapted physical education (APE), a subdiscipline of physical education, is one of the services frequently accessed by this population. Current literature on the experiences of children with autism spectrum disorder (ASD) has focused on special education classrooms, sensory perceptions, and general physical education classes. However, no prior studies had addressed how school-age children with ASD perceive their APE experience. Therefore, the purpose of this qualitative study was to use interpretive phenomenology to explore how middle school children (Grades 6 to 8) ages 10 to 14 with ASD perceive their APE experience. Data were collected from 10 middle school children through observations in their APE setting, drawings, and interviews. Exploratory, linguistic, and conceptual comments were used to deconstruct the data, develop themes in individual cases, and then identify connections across cases. Themes that emerged from the participants were their positive experiences in APE, understanding of the importance of being physically active, sedentary behavior in their spare time, and desire for time in APE. This study has positive social change implications such that it includes individuals with ASD into the commentary regarding their experiences and may help APE teachers by providing insight into the experience of children with ASD in APE, which may in turn help develop improved services for this population
Causes multiples de décès chez les personnes âgées au Québec, 2000-2004
Afin d'effectuer les classements et les analyses portant sur la mortalité selon la cause médicale de décès, il est d'usage d'utiliser uniquement la cause initiale de décès, qui représente la maladie ou le traumatisme ayant initié la séquence d'événements menant au décès. Cette méthode comporte plusieurs limites. L'analyse de causes multiples, qui a la qualité d'utiliser toutes les causes citées sur le certificat de décès, serait particulièrement indiquée pour mieux expliquer la mortalité puisque les décès sont souvent attribuables à plusieurs processus morbides concurrents.
L'analyse des causes multiples de décès chez les personnes âgées au Québec pour les années 2000-2004 permet d'identifier plusieurs conditions ayant contribué au décès, mais n'ayant toutefois pas été sélectionnées comme cause ayant initié le processus morbide. C'est particulièrement le cas de l'hypertension, de l'athérosclérose, de la septicémie, de la grippe et pneumonie, du diabète sucré et de la néphrite, syndrome néphrotique et néphropathie.
Cette recherche démontre donc l'importance de la prise en compte des causes multiples afin de dresser un portrait plus juste de la mortalité québécoise aux âges où se concentrent principalement les décès que le permet l'analyse de la cause initiale seule.To this day, mortality analysis has primarily focused on the underlying cause of death which represents the disease or injury which initiated the sequence of morbid events leading to the death. But since death is due to a complex process, especially at advanced ages, analysis based solely on this concept has its limitations and some causes are more likely to be identified as the underlying cause than others. Selecting only one cause per death may influence the relative importance of the various causes of death. Multiple causes of death statistics provide a more complete view of mortality patterns.
The analysis of multiple causes of death among the elderly in Quebec for 2000-2004 identifies certain conditions that contributed to death, but have not been selected as the cause that initiated the disease process. This is particularly the case of hypertension, atherosclerosis, sepsis, influenza and pneumonia, diabetes mellitus and nephritis, nephrotic syndrome and nephrosis.
This research therefore demonstrates the importance of taking into account multiple causes in order to provide a more accurate portrait of Quebec's mortality at older ages that allows analysis of the underlying cause alone
GHIGLS: HI mapping at intermediate Galactic latitude using the Green Bank Telescope
This paper introduces the data cubes from GHIGLS, deep Green Bank Telescope
surveys of the 21-cm line emission of HI in 37 targeted fields at intermediate
Galactic latitude. The GHIGLS fields together cover over 1000 square degrees at
9.55' spatial resolution. The HI spectra have an effective velocity resolution
about 1.0 km/s and cover at least -450 < v < +250 km/s. GHIGLS highlights that
even at intermediate Galactic latitude the interstellar medium is very complex.
Spatial structure of the HI is quantified through power spectra of maps of the
column density, NHI. For our featured representative field, centered on the
North Ecliptic Pole, the scaling exponents in power-law representations of the
power spectra of NHI maps for low, intermediate, and high velocity gas
components (LVC, IVC, and HVC) are -2.86 +/- 0.04, -2.69 +/- 0.04, and -2.59
+/- 0.07, respectively. After Gaussian decomposition of the line profiles, NHI
maps were also made corresponding to the narrow-line and broad-line components
in the LVC range; for the narrow-line map the exponent is -1.9 +/- 0.1,
reflecting more small scale structure in the cold neutral medium (CNM). There
is evidence that filamentary structure in the HI CNM is oriented parallel to
the Galactic magnetic field. The power spectrum analysis also offers insight
into the various contributions to uncertainty in the data. The effect of 21-cm
line opacity on the GHIGLS NHI maps is estimated.Comment: Accepted for publication in The Astrophysical Journal, 2015 July 16.
32 pages, 21 figures (Fig. 10 new). Minor revisions from review, particularly
Section 8 and Appendix C; results unchanged. Additional surveys added and
made available; new Appendix B. Added descriptions of available FITS files
and links to four illustrative movies on enhanced GHIGLS archive
(www.cita.utoronto.ca/GHIGLS/
Structure formation in a colliding flow: The Herschel view of the Draco nebula
The Draco nebula is a high Galactic latitude interstellar cloud likely to
have been formed by the collision of a Galactic halo cloud entering the disk of
the Milky Way. Such conditions are ideal to study the formation of cold and
dense gas in colliding flows of warm gas. We present Herschel-SPIRE
observations that reveal the fragmented structure of the interface between the
infalling cloud and the Galactic layer. This front is characterized by a
Rayleigh-Taylor instability structure. From the determination of the typical
length of the periodic structure (2.2 pc) we estimated the gas kinematic
viscosity and the turbulence dissipation scale (0.1 pc) that is compatible with
that expected if ambipolar diffusion is the main mechanism of energy
dissipation in the WNM. The small-scale structures of the nebula are typical of
that seen in some molecular clouds. The gas density has a log-normal
distribution with an average value of cm. The size of the
structures is 0.1-0.2 pc but this estimate is limited by the resolution of the
observations. The mass ranges from 0.2 to 20 M and the distribution
of the more massive clumps follows a power law . We
identify a mass-size relation with the same exponent as that found in GMCs
() but only 15% of the mass of the cloud is in gravitationally
bound structures. We conclude that the increase of pressure in the collision is
strong enough to trigger the WNM-CNM transition caused by the interplay between
turbulence and thermal instability as self-gravity is not dominating the
dynamics.Comment: 16 pages, A&A, in pres
On the O II ground configuration energy levels
The most accurate way to measure the energy levels for the O II 2p^3 ground
configuration has been from the forbidden lines in planetary nebulae. We
present an analysis of modern planetary nebula data that nicely constrain the
splitting within the ^2D term and the separation of this term from the ground
^4S_{3/2} level. We extend this method to H II regions using high-resolution
spectroscopy of the Orion nebula, covering all six visible transitions within
the ground configuration. These data confirm the splitting of the ^2D term
while additionally constraining the splitting of the ^2P term. The energies of
the ^2P and ^2D terms relative to the ground (^4S) term are constrained by
requiring that all six lines give the same radial velocity, consistent with
independent limits placed on the motion of the O+ gas and the planetary nebula
data.Comment: 20 pages, 3 figures. To be published in Ap
Chemical abundances in the protoplanetary disk LV2 (Orion): clues to the causes of the abundance anomaly in HII regions
Optical integral field spectroscopy of the archetype protoplanetary disk LV2
in the Orion Nebula is presented, taken with the VLT FLAMES/Argus fibre array.
The detection of recombination lines of CII and OII from this class of objects
is reported, and the lines are utilized as abundance diagnostics. The study is
complemented with the analysis of HST Faint Object Spectrograph ultraviolet and
optical spectra of the target contained within the Argus field of view. By
subtracting the local nebula background the intrinsic spectrum of the proplyd
is obtained and its elemental composition is derived for the first time. The
proplyd is found to be overabundant in carbon, oxygen and neon compared to the
Orion Nebula and the sun. The simultaneous coverage over LV2 of the CIII]
1908-A and [OIII] 5007-A collisionally excited lines (CELs) and CII and OII
recombination lines (RLs) has enabled us to measure the abundances of C++ and
O++ for LV2 with both sets of lines. The two methods yield consistent results
for the intrinsic proplyd spectrum, but not for the proplyd spectrum
contaminated by the generic nebula spectrum, thus providing one example where
the long-standing abundance anomaly plaguing metallicity studies of HII regions
has been resolved. These results would indicate that the standard
forbidden-line methods used in the derivation of light metal abundances in HII
regions in our own and other galaxies underestimate the true gas metallicity.Comment: Accepted by MNRAS November 8; 16 pages, 9 figs; typos corrected,
error in FWHMs in table 4 corrected in this versio
Integral field spectroscopy of selected areas of the Bright Bar and Orion-S cloud in the Orion Nebula
We present integral field spectroscopy of two selected zones in the Orion
Nebula obtained with the Potsdam Multi-Aperture Spectrophotometer (PMAS),
covering the optical spectral range from 3500 to 7200 A and with a spatial
resolution of 1". The observed zones are located on the prominent Bright Bar
and on the brightest area at the northeast of the Orion South cloud, both
containing remarkable ionization fronts. We obtain maps of emission line fluxes
and ratios, electron density and temperatures, and chemical abundances. We
study the ionization structure and morphology of both fields, which ionization
fronts show different inclination angles with respect to the plane of the sky.
We find that the maps of electron density, O+/H+ and O/H ratios show a rather
similar structure. We interpret this as produced by the strong dependence on
density of the [OII] lines used to derive the O+ abundance, and that our
nominal values of electron density-derived from the [SII] line ratio-may be
slightly higher than the appropriate value for the O+ zone. We measure the
faint recombination lines of OII in the field at the northeast of the Orion
South cloud allowing us to explore the so-called abundance discrepancy problem.
We find a rather constant abundance discrepancy across the field and a mean
value similar to that determined in other areas of the Orion Nebula, indicating
that the particular physical conditions of this ionization front do not
contribute to this discrepancy.Comment: 15 pages, 10 figures. Accepted for publication in MNRA
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