129 research outputs found
Spitzer IRS Observations of the Galactic Center: Shocked Gas in the Radio Arc Bubble
We present Spitzer IRS spectra (R ~600, 10 - 38 micron) of 38 positions in
the Galactic Center (GC), all at the same Galactic longitude and spanning
plus/minus 0.3 degrees in latitude. Our positions include the Arches Cluster,
the Arched Filaments, regions near the Quintuplet Cluster, the ``Bubble'' lying
along the same line-of-sight as the molecular cloud G0.11-0.11, and the diffuse
interstellar gas along the line-of-sight at higher Galactic latitudes. From
measurements of the [O IV], [Ne II], [Ne III], [Si II], [S III], [S IV], [Fe
II], [Fe III], and H_2 S(0), S(1), and S(2) lines we determine the gas
excitation and ionic abundance ratios. The Ne/H and S/H abundance ratios are ~
1.6 times that of the Orion Nebula. The main source of excitation is
photoionization, with the Arches Cluster ionizing the Arched Filaments and the
Quintuplet Cluster ionizing the gas nearby and at lower Galactic latitudes
including the far side of the Bubble. In addition, strong shocks ionize gas to
O^{+3} and destroy dust grains, releasing iron into the gas phase (Fe/H ~ 1.3
times 10^{-6} in the Arched Filaments and Fe/H ~ 8.8 times 10^{-6} in the
Bubble). The shock effects are particularly noticeable in the center of the
Bubble, but O is present in all positions. We suggest that the shocks
are due to the winds from the Quintuplet Cluster Wolf-Rayet stars. On the other
hand, the H_2 line ratios can be explained with multi-component models of warm
molecular gas in photodissociation regions without the need for H_2 production
in shocks.Comment: 51 pages, 17 figures To be published in the Astrophysical Journa
HST NICMOS Observations of the Polarization of NGC 1068
We have observed the polarized light at 2 micron in the center of NGC 1068
with HST NICMOS Camera 2. The nucleus is dominated by a bright, unresolved
source, polarized at a level of 6.0 pm 1.2% with a position angle of 122degr pm
1.5degr. There are two polarized lobes extending up to 8'' northeast and
southwest of the nucleus. The polarized flux in both lobes is quite clumpy,
with the maximum polarization occurring in the southwest lobe at a level of 17%
when smoothed to 0.23'' resolution. The perpendiculars to the polarization
vectors in these two lobes point back to the intense unresolved nuclear source
to within one 0.076'' Camera 2 pixel, thereby confirming that this is the
illuminating source of the scattered light and therefore the probable AGN
central engine. Whereas the polarization of the nucleus is probably caused by
dichroic absorption, the polarization in the lobes is almost certainly caused
by scattering, with very little contribution from dichroic absorption. Features
in the polarized lobes include a gap at a distance of about 1'' from the
nucleus toward the southwest lobe and a ``knot'' of emission about 5''
northeast of the nucleus. Both features had been discussed by ground-based
observers, but they are much better defined with the high spatial resolution of
NICMOS. The northeast knot may be the side of a molecular cloud that is facing
the nucleus, which cloud may be preventing the expansion of the northeast radio
lobe at the head of the radio synchrotron-radiation-emitting jet. We also
report the presence of two ghosts in the Camera 2 polarizers. These had not
been detected previously (Hines et al. 2000) because they are relatively faint
and require observations of a source with a large dynamic range.Comment: 17 pages, 4 figure
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MP32-03 THE IMPACT OF SOCIAL DEPRIVATION ON ANTERIOR URETHRAL STRICTURE RECURRENCE AFTER URETHROPLASTY—A TRAUMA AND UROLOGIC RECONSTRUCTIVE NETWORK OF SURGEONS (TURNS) ANALYSIS
Hubble Space Telescope NICMOS Polarization Measurements of OMC-1
We present 2micron polarization measurements of positions in the BN region of
the Orion Molecular Cloud (OMC-1) made with NICMOS Camera 2 (0.2'' resolution)
on HST. Our results are as follows: BN is sim 29% polarized by dichroic
absorption and appears to be the illuminating source for most of the nebulosity
to its north and up to sim 5'' to its south. Although the stars are probably
all polarized by dichroic absorption, there are a number of compact, but
non-point-source, objects that could be polarized by a combination of both
dichroic absorption and local scattering of star light. We identify several
candidate YSOs, including an approximately edge-on bipolar YSO 8.7'' east of
BN, and a deeply-embedded variable star. Additional strongly polarized sources
are IRc2-B, IRc2-D, and IRc7, all of which are obviously self-luminous at
mid-infrared wavelengths and may be YSOs. None of these is a reflection nebula
illuminated by a star located near radio source I, as was previously suggested.
Other IRc sources are clearly reflection nebulae: IRc3 appears to be
illuminated by IRc2-B or a combination of the IRc2 sources, and IRc4 and IRc5
appear to be illuminated by an unseen star in the vicinity of radio source I,
or by Star n or IRc2-A. Trends in the magnetic field direction are inferred
from the polarization of the 26 stars that are bright enough to be seen as
NICMOS point sources. The most polarized star has a polarization position angle
different from its neighbors by sim 40^o, but in agreement with the grain
alignment inferred from millimeter polarization measurements of the cold dust
cloud in the southern part of OMC-1.Comment: 41 pages, 8 figures, 4 tables, to appear in The Astrophysical Journa
Screensaver: an open source lab information management system (LIMS) for high throughput screening facilities
<p>Abstract</p> <p>Background</p> <p>Shared-usage high throughput screening (HTS) facilities are becoming more common in academe as large-scale small molecule and genome-scale RNAi screening strategies are adopted for basic research purposes. These shared facilities require a unique informatics infrastructure that must not only provide access to and analysis of screening data, but must also manage the administrative and technical challenges associated with conducting numerous, interleaved screening efforts run by multiple independent research groups.</p> <p>Results</p> <p>We have developed Screensaver, a free, open source, web-based lab information management system (LIMS), to address the informatics needs of our small molecule and RNAi screening facility. Screensaver supports the storage and comparison of screening data sets, as well as the management of information about screens, screeners, libraries, and laboratory work requests. To our knowledge, Screensaver is one of the first applications to support the storage and analysis of data from both genome-scale RNAi screening projects and small molecule screening projects.</p> <p>Conclusions</p> <p>The informatics and administrative needs of an HTS facility may be best managed by a single, integrated, web-accessible application such as Screensaver. Screensaver has proven useful in meeting the requirements of the ICCB-Longwood/NSRB Screening Facility at Harvard Medical School, and has provided similar benefits to other HTS facilities.</p
The American Association for the Surgery of Trauma renal injury grading scale: Implications of the 2018 revisions for injury reclassification and predicting bleeding interventions.
BackgroundIn 2018, the American Association for the Surgery of Trauma (AAST) published revisions to the renal injury grading system to reflect the increased reliance on computed tomography scans and non-operative management of high-grade renal trauma (HGRT). We aimed to evaluate how these revisions will change the grading of HGRT and if it outperforms the original 1989 grading in predicting bleeding control interventions.MethodsData on HGRT were collected from 14 Level-1 trauma centers from 2014 to 2017. Patients with initial computed tomography scans were included. Two radiologists reviewed the scans to regrade the injuries according to the 1989 and 2018 AAST grading systems. Descriptive statistics were used to assess grade reclassifications. Mixed-effect multivariable logistic regression was used to measure the predictive ability of each grading system. The areas under the curves were compared.ResultsOf the 322 injuries included, 27.0% were upgraded, 3.4% were downgraded, and 69.5% remained unchanged. Of the injuries graded as III or lower using the 1989 AAST, 33.5% were upgraded to grade IV using the 2018 AAST. Of the grade V injuries, 58.8% were downgraded using the 2018 AAST. There was no statistically significant difference in the overall areas under the curves between the 2018 and 1989 AAST grading system for predicting bleeding interventions (0.72 vs. 0.68, p = 0.34).ConclusionAbout one third of the injuries previously classified as grade III will be upgraded to grade IV using the 2018 AAST, which adds to the heterogeneity of grade IV injuries. Although the 2018 AAST grading provides more anatomic details on injury patterns and includes important radiologic findings, it did not outperform the 1989 AAST grading in predicting bleeding interventions.Level of evidencePrognostic and Epidemiological Study, level III
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The Impact of Social Deprivation on Anterior Urethral Stricture Recurrence After Urethroplasty - A Trauma and Urologic Reconstructive Network of Surgeons (TURNS) Analysis.
Introduction and objectivesSeveral factors influence recurrence after urethral stricture repair. The impact of socioeconomic factors on stricture recurrence after urethroplasty is poorly understood. This study aims to assess the impact that social deprivation, an area-level measure of disadvantage, has on urethral stricture recurrence after urethroplasty.MethodsWe performed a retrospective review of patients undergoing urethral reconstruction by surgeons participating in a collaborative research group. Home zip code was used to calculate Social Deprivation Indices (SDI; 0-100), which quantifies the level of disadvantage across several sociodemographic domains collected in the American Community Survey. Patients without zip code data were excluded from the analysis. The Cox Proportional Hazards model was used to study the association between SDI and the hazard of functional recurrence, adjusting for stricture characteristics as well as age and body mass index.ResultsMedian age was 46.0 years with a median follow up of 367 days for the 1452 men included in the study. Patients in the fourth SDI quartile (worst social deprivation) were more likely to be active smokers with traumatic and infectious strictures compared to the first SDI quartile. Patients in the fourth SDI quartile had 1.64 times the unadjusted hazard of functional stricture recurrence vs patients in the first SDI quartile (95% CI 1.04-2.59). Compared to anastomotic ± excision, substitution only repair had 1.90 times the unadjusted hazard of recurrence. The adjusted hazard of recurrence was 1.08 per 10-point increase in SDI (95% CI 1.01-1.15, P = .027).ConclusionsPatient social deprivation identifies those at higher risk for functional recurrence after anterior urethral stricture repair, offering an opportunity for preoperative counseling and postoperative surveillance. Addressing these social determinants of health can potentially improve outcomes in reconstructive surgery
A research agenda for seed-trait functional ecology
Trait-based approaches have improved our understanding of plant evolution, community assembly and ecosystem functioning. A major challenge for the upcoming decades is to understand the functions and evolution of early life-history traits, across levels of organization and ecological strategies. Although a variety of seed traits are critical for dispersal, persistence, germination timing and seedling establishment, only seed mass has been considered systematically. Here we suggest broadening the range of morphological, physiological and biochemical seed traits to add new understanding on plant niches, population dynamics and community assembly. The diversity of seed traits and functions provides an important challenge that will require international collaboration in three areas of research. First, we present a conceptual framework for a seed ecological spectrum that builds upon current understanding of plant niches. We then lay the foundation for a seed-trait functional network, the establishment of which will underpin and facilitate trait-based inferences. Finally, we anticipate novel insights and challenges associated with incorporating diverse seed traits into predictive evolutionary ecology, community ecology and applied ecology. If the community invests in standardized seed-trait collection and the implementation of rigorous databases, major strides can be made at this exciting frontier of functional ecology
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