Confirmation of Interstellar Acetone Snyder, Lewis E; Lovas, F. J; Mehringer, David M ...
The Astrophysical journal,
10/2002, Letnik:
578, Številka:
1
Journal Article
We have identified vibrationally excited CH sub(3)CH sub(2)CN (ethyl cyanide) for the first time in the interstellar medium. Using the Caltech Submillimeter Observatory, the ...Berkeley-Illinois-Maryland Association Array, and the Caltech Millimeter Array, we have detected several transitions from both the v sub(b) = 1 in-plane bending state and the v sub(t) = 1 torsional state in the Sgr B2(N-LMH) source. Because these excited states lie near 300 K above ground, vibrationally excited CH sub(3)CH sub(2)CN is potentially a useful probe of the hottest regions of dense, dusty molecular cloud cores where massive star formation is occurring. In addition, this identification will help account for many unidentified and misidentified spectral lines observed in hot molecular cores.
We have mapped Ne II (12.8 km) and S IV (10.5 km) emission from W51 IRS 2 with TEXES on Gemini North, and we compare these data to VLA free-free observations and VLT near-infrared images. With 0.5" ...spatial and 4 km s super(-1) spectral resolution, we are able to separate the ionized gas into several components: an extended H II region on the front surface of the molecular cloud, several embedded compact H II regions, and a streamer of high-velocity gas. We interpret the high-velocity streamer as a processing or fanlike jet, which has emerged from the molecular cloud into an OB star cluster where it is being ionized.
Background Regional collaborative organizations provide an effective structure for improving the quality of surgical care. With low complication rates and a long latency between surgical care and ...outcomes such as survival and local recurrence, quality measurement in breast cancer surgery is ideally suited to process measures. Diagnostic biopsy technique for breast cancer diagnosis is measurable and amenable to change at the provider level. We present initial results from our analysis of institutional variation in surgical and core needle biopsy use within a regional breast cancer quality collaborative. Methods Established in 2006, the Michigan Breast Oncology Quality Initiative (MiBOQI) consists of 18 hospitals collecting data on breast cancer care using the National Comprehensive Cancer Centers Network (NCCN) Oncology Outcomes Database Project platform to analyze and compare breast cancer practices and outcomes amongst member institutions. Institutional review board approval is obtained at each site. Data are submitted electronically to the NCCN and analyzed for concordance with practice guidelines. Aggregate and blinded data are shared with project directors and institutions at collaborative meetings, and ongoing practice patterns are observed for change. We analyzed variation in breast biopsy technique for initial cancer diagnosis over time and between institutions. Diagnostic biopsies were categorized as core needle, surgical excisional, surgical incisional, and other surgical biopsy. Results Procedural data for 8,066 patients treated for breast cancer between November 1, 2006 and December 31, 2009 were analyzed. The mean patient age was 59.5 years (range, 25.4–90.0 years). Within MiBOQI, 21% of patients underwent surgical biopsy for initial diagnosis. The percentage of patients undergoing surgical biopsy ranged from 8% to 37%, and the majority of surgical biopsies were classified as excisional biopsies. Patients with ductal carcinoma in situ were more likely to undergo surgical biopsy compared to those with invasive cancer (30.4% vs 17.8%; P < .001). There was no association between biopsy type and patient age, race, or comorbidity. Data on biopsy technique were shared with site project directors and a target surgical biopsy rate of <15% was chosen by consensus. Site project directors disseminated the data to their institutions and developed action plans for provider and patient education. Over the study period, the percentage of cases undergoing surgical biopsy for the entire MiBOQI collaborative decreased from 21% to 15% ( P < .001). Conclusion The regional quality collaborative model can be used to collect, analyze, and disseminate surgical breast care quality data to organizations and treating physicians. These data can be used to describe patterns of care and make comparisons over time and between organizations. These data can also be used to set regional quality standards and provide an avenue for physician-led quality improvement.
A Submillimeter HCN Laser in IRC +10216 Schilke, Peter; Mehringer, David M; Menten, Karl M
The Astrophysical journal,
01/2000, Letnik:
528, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We report the detection of a strong submillimeter-wavelength HCN laser line at a frequency near 805 GHz toward the carbon star IRC +10216. This line, the J=9-8 rotational transition within the (0400) ...vibrationally excited state, is one of a series of HCN laser lines that were first detected in the laboratory in the early days of laser spectroscopy. Since its lower energy level is 4200 K above the ground state, the laser emission must arise from the innermost part of IRC +10216's circumstellar envelope. To better characterize this environment, we observed other, thermally emitting, vibrationally excited HCN lines and found that they, like the laser line, arise in a region of temperature approximately 1000 K that is located within the dust formation radius; this conclusion is supported by the line width of the laser. The (0400), J=9-8 laser might be chemically pumped and may be the only known laser (or maser) that is excited both in the laboratory and in space by a similar mechanism.
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