61 research outputs found

    Radio Continuum and Recombination Line Study of UC HII Regions with Extended Envelopes

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    We have carried out 21 cm radio continuum observations of 16 UC HII regions using the VLA (D-array) in search of associated extended emission. We have also observed H76Ī±_\alpha recombination line towards all the sources and He76Ī±_\alpha line at the positions with strong H76Ī±_\alpha line emission. The UC HII regions have simple morphologies and large (>10) ratios of single-dish to VLA fluxes. Extended emission was detected towards all the sources. The extended emission consists of one to several compact components and a diffuse extended envelope. All the UC HII regions but two are located in the compact components, where the UC HII regions always correspond to their peaks. The compact components with UC HII regions are usually smaller and denser than those without UC HII regions. Our recombination line observations indicate that the ultracompact, compact, and extended components are physically associated. The UC HII regions and their associated compact components are likely to be ionized by the same sources on the basis of the morphological relations mentioned above. This suggests that almost all of the observed UC HII regions are not `real' UC HII regions and that their actual ages are much greater than their dynamical age (<10000 yr). We find that most of simple UC HII regions previously known have large ratios of single-dish to VLA fluxes, similar to our sources. Therefore, the `age problem' of UC HII regions does not seem to be as serious as earlier studies argued. We present a simple model that explains extended emission around UC HII regions. Some individual sources are discussed.Comment: 29 pages, 28 postscript figures, Accepted for publication in Ap

    Can intrinsic alignments of elongated low-mass galaxies be used to map the cosmic web at high redshift?

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    Hubble Space Telescope observations show that low-mass (Māˆ—=109āˆ’1010MāŠ™M_*=10^9-10^{10}M_{\odot}) galaxies at high redshift (z=1.0āˆ’2.5z=1.0-2.5) tend to be elongated (prolate) rather than disky (oblate) or spheroidal. This is explained in zoom-in cosmological hydrodynamical simulations by the fact that these galaxies are forming in cosmic web filaments where accretion happens preferentially along the direction of elongation. We ask whether the elongated morphology of these galaxies allows them to be used as effective tracers of cosmic web filaments at high redshift via their intrinsic alignments. Using mock lightcones and spectroscopically-confirmed galaxy pairs from the CANDELS survey, we test two types of alignments: (1) between the galaxy major axis and the direction to nearby galaxies of any mass, and (2) between the major axes of nearby pairs of low-mass, likely prolate, galaxies. The mock lightcones predict strong signals in 3D real space, 3D redshift space, and 2D projected redshift space for both types of alignments (assuming prolate galaxy orientations are the same as those of their host prolate halos), but we do not detect significant alignment signals in CANDELS observations. However, we show that spectroscopic redshifts have been obtained for only a small fraction of highly elongated galaxies, and accounting for spectroscopic incompleteness and redshift errors significantly degrades the 2D mock signal. This may partly explain the alignment discrepancy and highlights one of several avenues for future work.Comment: Re-submitted to MNRAS after minor revision

    Molecular Counterparts of Ultracompact HII Regions with Extended Envelopes

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    We carried out 13CO J=1-0, CS, and C34S J=2-1 and J=3-2 line observations of molecular clouds associated with 16 ultracompact (UC) HII regions with extended envelopes. The molecular clouds are the ones that give birth to rich stellar clusters and/or very massive (O7-O4) stars. Our data show that the clouds are very clumpy and of irregular morphology. They usually have much larger masses, velocity dispersions, and fractions of dense gas than molecular clouds that form early B or late O stars. This is compatible with earlier findings that more massive stars form in more massive cores. 13CO cores are in general associated with compact HII regions regardless of the presence of UC HII regions therein. In contrast, CS cores are preferentially associated with compact HII regions that contain UC HII regions. As with the fact that the compact HII regions containing UC HII regions are more compact than those not associated with UC HII regions, these indicate that the former may be in an earlier evolutionary phase than the latter. The diffuse extended envelopes of HII regions often develop in the direction of decreasing molecular gas density. Based on detailed comparison of molecular line data with radio continuum and recombination line data, the extended ionized envelopes are likely the results of champagne flows in at least 10 sources in our sample. Together these results appear to support a published suggestion that the extended emission around UC HII regions can be naturally understood by combining the champagne flow model with the hierarchical structure of molecular clouds. We discuss the implication of our results for the blister model of HII regions.Comment: 36 pages, including 30 figures, accepted for publication in Ap

    Orthopedic Surgeon's Awareness Can Improve Osteoporosis Treatment Following Hip Fracture: A Prospective Cohort Study

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    Through retrospective Jeju-cohort study at 2005, we found low rates of detection of osteoporosis (20.1%) and medication for osteoporosis (15.5%) in those who experienced hip fracture. This study was to determine the orthopedic surgeons' awareness could increase the osteoporosis treatment rate after a hip fracture and the patient barriers to osteoporosis management. We prospectively followed 208 patients older than 50 yr who were enrolled for hip fractures during 2007 in Jeju-cohort. Thirty four fractures in men and 174 in women were treated at the eight hospitals. During the study period, orthopedic surgeons who worked at these hospitals attended two education sessions and were provided with posters and brochures. Patients were interviewed 6 months after discharge using an evaluation questionnaire regarding their perceptions of barriers to osteoporosis treatment. The patients were followed for a minimum of one year. Ninety-four patients (45.2%) underwent detection of osteoporosis by dual energy x-ray absorptiometry and 67 (32.2%) were prescribed medication for osteoporosis at the time of discharge. According to the questionnaire, the most common barrier to treatment for osteoporosis after a hip fracture was patients reluctance. The detection and medication rate for osteoporosis after hip fracture increased twofold after orthopedic surgeons had attended the intervention program. Nevertheless, the osteoporosis treatment rate remains inadequate

    GFS, a preparation of Tasmanian Undaria pinnatifida is associated with healing and inhibition of reactivation of Herpes

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    BACKGROUND: We sought to assess whether GFS, a proprietary preparation of Tasmanian Undaria pinnatifida, has effects on healing or re-emergence of Herpetic infections, and additionally, to assess effects of GFS in vitro. Undaria is the most commonly eaten seaweed in Japan, and contains sulphated polyanions and other components with potential anti-viral activity. Herpes simplex virus type 1 (HSV-1) infections have lower reactivation rates and Herpes type 2 (HSV-2) infections have lower incidence in Japan than in the west. METHODS: Patients with active (15 subjects) or latent (6 subjects) Herpetic infections (HSV-1, 2, EBV, Zoster) were monitored for response to ingestion of GFS. GFS extract was tested in vitro for human T cell mitogenicity and anti-Herpes activity. RESULTS: Ingestion of GFS was associated with increased healing rates in patients with active infections. In addition, patients with latent infection remained asymptomatic whilst ingesting GFS. GFS extract inhibited Herpes viruses in vitro and was mitogenic to human T cells in vitro. CONCLUSIONS: Ingestion of GFS has inhibitory effects on reactivation and is associated with increased rate of healing after Herpetic outbreaks. GFS extract potently inhibited Herpes virus in vitro, and had mitogenic effects on human T cells

    Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

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    Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14Ā·2 per cent (646 of 4544) and the 30-day mortality rate was 1Ā·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7Ā·61, 95 per cent c.i. 4Ā·49 to 12Ā·90; P < 0Ā·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0Ā·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

    Aluminum toxicity in childhood

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    Aluminum intoxication is an iatrogenic disease caused by the use of aluminum compounds for phosphate binding and by the contamination of parenteral fluids. Although organ aluminum deposition was noted as early as 1880 and toxicity was documented in the 1960s, the inability to accurately measure serum and tissue aluminum prevented delineation of its toxic effects until the 1970s. Aluminum toxicity has now been conclusively shown to cause encephalopathy, metabolic bone disease, and microcytic anemia.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47831/1/467_2004_Article_BF00869743.pd

    Virtual Interviewing Tips for the Otolaryngology Match Cycle During the COVID-19 Pandemic

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    Virtual interviews are planned for the upcoming 2020-2021 residency cycle. This presents a unique challenge for medical students. Due to the importance of the interaction of applicants and interviewers during the interview, medical students should thoroughly prepare for the upcoming virtual interview season. We offer practical and realistic concepts and techniques to optimize their interview experience. Technology and audiovisual equipment should be adjusted and enhanced to minimize video conferencing application errors and interview downtime. The applicantā€™s interview environment should focus on proper lighting, background, camera angles, and minimizing unwanted distractions. Mock interview sessions are invaluable to applicants and provide the opportunity to simulate the interview, refine their technology, adjust their environment, and become more comfortable in a virtual interview setting. These actions will prevent unnecessary disruptions and increase the focus of the interview toward the communication between the applicant and the interviewer
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