670 research outputs found
New North American records of Pyraloidea (Lepidoptera: Crambidae, Pyralidae) from southern Florida
We report six new North American records, one new state record, and one rare record of pyraloid moths from southern Florida, together with diagnostic characters for all taxa. We transfer Ennomosia Amsel from Spilomelinae to Glaphyriinae, Cangetta micralis (Hampson) n. comb. from Deuterophysa Warren, and Microthyris lelex (Cramer) n. comb. from Cyclocena Möschler. We revise Pseudocabotia Blanchard and Knudson rev. stat. to a subgenus of Ancylosis Zeller, with its type species A. (P.) balconiensis (Blanchard and Knudson) n. comb., and discuss the classifi cation of Cabotia Ragonot as a subgenus of Ancylosis
Revealing New Physical Structures in the Supernova Remnant N63A through Chandra Imaging Spectroscopy
We present Chandra X-ray observations of the supernova remnant (SNR) N63A in
the Large Magellanic Cloud (LMC). N63A, one of the brightest LMC remnants, is
embedded in an H II region and probably associated with an OB association. The
optical remnant consists of three lobes of emission contained within the
approximately three times larger X-ray remnant. Our Chandra data reveal a
number of new physical structures in N63A. The most striking of these are the
several ``crescent''-shaped structures located beyond the main shell that
resemble similar features seen in the Vela SNR. In Vela, these have been
interpreted as arising from high speed clumps of supernova ejecta interacting
with the ambient medium. Another distinct feature of the remnant is a roughly
triangular ``hole'' in the X-ray emission near the location of the optical
lobes and the brightest radio emission. X-ray spectral analysis shows that this
deficit of emission is a result of absorption by an intervening dense cloud
with a mass of ~450 M_sun that is currently being engulfed by the remnant's
blast wave. We also find that the rim of the remnant, as well as the
crescent-shaped features, have considerably softer X-ray spectra than the
interior. Limits on hard X-ray emission rule out a young, energetic pulsar in
N63A, but the presence of an older or less active one, powering a wind nebula
with a luminosity less than ~4e10^34 erg/s, is allowed.Comment: 18 pages, 5 figures (2 color), accepted for publication in Ap
Supernova Remnants in the Magellanic Clouds. IV. X-Ray Emission from the Largest SNR in the LMC
We present the first X-ray detection of SNR 0450-70.9 the largest known
supernova remnant (SNR) in the Large Magellanic Cloud. To study the physical
conditions of this SNR, we have obtained XMM-Newton X-ray observations, optical
images and high-dispersion spectra, and radio continuum maps. Optical images of
SNR 0450-70.9 show a large, irregular elliptical shell with bright filaments
along the eastern and western rims and within the shell interior. The interior
filaments have higher [S II]/Halpha ratios and form an apparent inner shell
morphology. The X-ray emission region is smaller than the full extent of the
optical shell, with the brightest X-ray emission found within the small
interior shell and on the western rim of the large shell. The expansion
velocity of the small shell is ~220 km/s, while the large shell is ~120 km/s.
The radio image shows central brightening and a fairly flat radio spectral
index over the SNR. However, no point X-ray or radio source corresponding to a
pulsar is detected and the X-ray emission is predominantly thermal. Therefore,
these phenomena can be most reasonably explained in terms of the advanced age
of the large SNR. Using hydrodynamic models combined with a nonequilibrium
ionization model for thermal X-ray emission, we derived a lower limit on the
SNR age of about 45,000 yr, well into the later stages of SNR evolution.
Despite this, the temperature and density derived from spectral fits to the
X-ray emission indicate that the remnant is still overpressured, and thus that
the development is largely driven by hot gas in the SNR interior.Comment: Accepted for publication in The Astrophysical Journa
A Continuum Formulation of Stress Correlations of Dislocations in Two Dimensions
The Continuum Dislocation Dynamics theory (CDD) of crystal plasticity, utilizing a second-order dislocation density tensor, is a powerful tool in understanding and modeling the dynamic behavior of dislocations on microscopic scales. Using this model, a number of benchmark systems have been tested. All results show excellent agreement with both analytic solutions, where available, as well as discrete simulations. While accurate solutions have been found for effectively one dimensional systems, fully two- and three-dimensional systems increase the complexity of the problem. In order to predict the behavior of the continuum density accurately, it must be properly understood as an ensemble average over discrete distributions. In this work, an overview of a simplified, integrated form of the CDD method is presented, along with an overview of one-dimensional results compared with both analytic solutions and discrete simulation. Then, the results from CDD for a distribution of one-dimensional glide planes in a two-dimensional elastic medium is presented. Using comparisons with Discrete Dislocation Dynamics (DDD) in a few simple systems, the multi-component stress field which must be considered for dislocation density motion is derived and demonstrated
Seeking counselling for mood disorders in a cardiac centre: a pilot survey of patients’ views
Research suggests a relationship exists between patients with ischemic heart trauma, and mood disorders and that there is therefore a need for psychosocial assessment and, where necessary, treatment for these disorders among heart attack patients [1]. Yet, assessment and treatment for mood disorders is rarely a priority in the cardiologist's office. Thus, counselling therapies for cardiac patients with co-occurring mood disorder are rarely considered or addressed in the cardiologist's office. This study sought to investigate whether cardiac patients would use counselling services if offered in the cardiologist's office. Results suggested mixed sentiments regarding counselling treatment for mood disorders in the cardiologist's office, particularly with regard to sex-differences. Discussion focuses on these sex-differences and the role aspects of ‘gender' and ‘masculinity' may play in accounting for such differences. The paper also discusses the significance of age differences. Implications for interdisciplinary collaboration are presented
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