1,025 research outputs found
Chandra Observations of the Optically Dark GRB030528
The X-ray-rich GRB030528 was detected by the HETE satellite and its
localization was rapidly disseminated. However, early optical observations
failed to detect a counterpart source. In a 2-epoch ToO observation with
Chandra, we discovered a fading X-ray source likely counterpart to GRB030528.
The source brightness was typical of X-ray afterglows observed at similar
epochs. Other observers detected an IR source at a location consistent with the
X-ray source. The X-ray spectrum is not consistent with a large absorbing
column.Comment: 4 pages, 1 figures, to appear in Santa Fe GRB Conference Proceedings,
200
Previously Claimed(/Unclaimed) X-ray Emission Lines in High Resolution Afterglow Spectra
We review the significance determination for emission lines in the Chandra
HETGS spectrum for GRB020813, and we report on a search for additional lines in
high resolution Chandra spectra. No previously unclaimed features are found. We
also discuss the significance of lines sets reportedly discovered using XMM
data for GRB011211 and GRB030227. We find that these features are likely of
modest, though not negligible, significance.Comment: 4 pages, 1 figures, to appear in Santa Fe GRB Conference Proceedings,
200
Optical and X-ray Observations of the Afterglow to XRF030723
The X-ray-flash XRF030723 was detected by the HETE satellite and rapidly
disseminated, allowing for an optical transient to be detected ~1 day after the
burst. We discuss observations in the optical with Magellan, which confirmed
the fade of the optical transient. In a 2-epoch ToO observation with Chandra,
we discovered a fading X-ray source spatially coincident with the optical
transient. We present spectral fits to the X-ray data. We also discuss the
possibility that the source underwent a rebrightening in the X-rays, as was
observed in the optical. We find that the significance of a possible
rebrightening is very low (~1 sigma).Comment: 4 pages, 2 figures, to appear in Santa Fe GRB Conference Proceedings,
200
Imaging and burst location with the EXIST high-energy telescope
The primary instrument of the proposed EXIST mission is a coded mask high
energy telescope (the HET), that must have a wide field of view and extremely
good sensitivity. It will be crucial to minimize systematic errors so that even
for very long total integration times the imaging performance is close to the
statistical photon limit. There is also a requirement to be able to reconstruct
images on-board in near real time in order to detect and localize gamma-ray
bursts. This must be done while the spacecraft is scanning the sky. The
scanning provides all-sky coverage and is key to reducing systematic errors.
The on-board computational problem is made even more challenging for EXIST by
the very large number of detector pixels. Numerous alternative designs for the
HET have been evaluated. The baseline concept adopted depends on a unique coded
mask with two spatial scales. Monte Carlo simulations and analytic analysis
techniques have been used to demonstrate the capabilities of the design and of
the proposed two-step burst localization procedure
Airbag-related chest wall burn as a marker of underlying injury: a case report
<p>Abstract</p> <p>Introduction</p> <p>This case of a man who sustained an airbag-induced thoracic injury and burn, highlights the potential harm that can be caused by airbags. It also serves to illustrate that a surface burn which looks small and benign can actually be a surface marker of a more serious injury. Staff working in emergency departments need to be aware of the risk of possible airbag-associated injuries.</p> <p>Case presentation</p> <p>A 65-year-old man was the driver in a frontal collision. He was wearing a seatbelt. The airbag was activated and caused a superficial chest wall burn. Initial chest x-rays were unremarkable but following deterioration in his condition, a computed tomography scan revealed a serious sternal fracture. The location of the fracture was marked on the surface by the burn.</p> <p>Conclusion</p> <p>Airbags can cause significant chest wall injuries and burns. Surface burns at the point of impact should not be dismissed as trivial as the forces involved can cause significant injury. We recommend that all people with chest wall injuries and/or burns due to airbags should have more detailed chest imaging as initial emergency radiographs can be falsely reassuring.</p
Temporary Bonding with Polydimethylglutarimide Based Lift Off Resist as a Layer Transfer Platform
Bonding of lift off resist (LOR) was performed to realize temporary wafer bonding without residue. Bonding process conditions such as spin speed, pre-bake temperature, and bonding temperature were optimized to obtain a large bonded area with high bond strength. Under optimized process conditions, a bonded area covering over 98% of the wafer surface, with a room temperature bond strength of nearly 5 J/m2 is achieved. During razor blade testing, fracture often occurs at the Si wafer. Moreover, debonding using an N-Methyl-2-pyrrolidone (NMP)-based solvent left the wafer surface extremely small amount of residue. Thus, the optimized bonding processed developed in this research is suitable for a clean temporary bonding process
An Evaluation Framework for Obesity Prevention Policy Interventions
As the emphasis on preventing obesity has grown, so have calls for interventions that extend beyond individual behaviors and address changes in environments and policies. Despite the need for policy action, little is known about policy approaches that are most effective at preventing obesity. The Centers for Disease Control and Prevention (CDC) and others are funding the implementation and evaluation of new obesity prevention policies, presenting a distinct opportunity to learn from these practice-based initiatives and build the body of evidence-based approaches. However, contributions from this policy activity are limited by the incomplete and inconsistent evaluation data collected on policy processes and outcomes. We present a framework developed by the CDC-funded Center of Excellence for Training and Research Translation that public health practitioners can use to evaluate policy interventions and identify the practice-based evidence needed to fill the gaps in effective policy approaches to obesity prevention
Deep imaging of the field of the Z = 4.9 quasar PC 1247+3406, and faint galaxy counts in the K band with the Keck telescope
We present deep images in the K. band of the field of the quasar PC 1247 + 3406 at z = 4.897, obtained using the near-infrared camera on the W. M. Keck telescope. A number of faint sources have been detected, some of which appear to be quite red. Their nature and redshifts remain uncertain at this time. These data are combined with deep Keck infrared images of five additional fields and present galaxy counts reaching down to K_s = 22 mag, comparable to the deepest K-band surveys to date. The data presented here are in good agreement with the Hawaii Deep Survey and represent the first independent verification of those results. The slope of the log N-log S relation derived from these data agrees well with the Hawaii Deep Survey, while the counts are slightly higher, especially at the faintest levels probed here. This may be due to a presence of groups or clusters around the target objects at high redshifts
- …