1,418 research outputs found

    Retention and Subsequent Release of Radioactivity from the Incineration of Wastes Containing Microspheres

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    Incineration has been chosen as the preferred method for disposing of animal carcasses containing radioactive microspheres at East Carolina University. Routine surveys of ash from successive non-radioactive burns have shown significant contamination from previously incinerated microspheres. Past studies on microsphere incineration quantified the amount of activity retained in ash, but did not address any subsequent releases. This topic was not considered in earlier studies because, in most cases, the carcasses were placed in some type of container to facilitate recovery of ash, preventing contamination of the incinerator refractory. Five sets of controlled burns were performed to quantify the subsequent releases of the microsphere radioisotopes Ce-141, Sn-113, Ru-103, Nb-95, and Sc-46. Each set consisted of three successive burns. The first burn of each set incinerated a non-radioactive carcass, the second burn, a radioactive carcass, and the third, a non-radioactive carcass. In all of the burns, the carcasses were placed directly on the incinerator refractory floor, as is the standard procedure during normal operations. The data collected document that significant subsequent releases of activity from the refractory do occur. This results in contamination of ash from non-radioactive burns. The actual amount of activity released varies with each isotope. These findings have caused East Carolina University to re-evaluate the quantities of radioactivity which may be burned, and to initiate a program to monitor all incinerator ash for gamma emitting radionuclides.Master of Science in Public Healt

    Sources of inversion variation in the small single copy (SSC) region of chloroplast genomes

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141571/1/ajb21751.pd

    Description and evaluation of a ventriculo-coronary artery bypass device that provides bi-directional coronary flow

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    Objective: The objective of this study was to assess acute patency of a new myocardial revascularization device that connects the left ventricular cavity to a coronary artery (termed ventriculo-coronary artery bypass, VCAB) thereby providing proximal and distal blood flow from the site of the anastomosis. Methods: A device made of expanded polytetrafluoroethylene and low density polyethylene was implanted from the base of the left ventricle to the mid left anterior descending coronary artery (LAD) in 11 juvenile domestic pigs using a beating heart approach. Flow rates were measured in the distal LAD before and after implant using ultrasonic flow techniques, and patency was assessed at explant at either 2 or 4 weeks post-implantation. Myocardial perfusion using positron emission tomography (PET) was assessed in a separate set of pigs (n=2) revascularized by VCAB 2 weeks post-implant. Results: Net forward flow distal to the implanted device was 73±15% of native LAD flow. PET demonstrated that the target myocardium was perfused at 85% of that seen in the remote, control myocardium. Device patency rate was 80% (4/5) at 2 weeks in one set of pigs and 83% (5/6) at 4 weeks in a second set of pigs. Histologic analysis showed formation of neointima along the extraventricular segment of the device. Conclusions: This study demonstrates the promise of perfusing ischemic myocardium using a VCAB approach with a device that provides blood flow both proximal and distal to the anastomosis. Patency of the transmyocardial device was encouraging at 2 and 4 weeks and warrants further investigatio

    NASA Sea Ice Validation Program for the Defense Meteorological Satellite Program Special Sensor Microwave Imager

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    The history of the program is described along with the SSM/I sensor, including its calibration and geolocation correction procedures used by NASA, SSM/I data flow, and the NASA program to distribute polar gridded SSM/I radiances and sea ice concentrations (SIC) on CD-ROMs. Following a discussion of the NASA algorithm used to convert SSM/I radiances to SICs, results of 95 SSM/I-MSS Landsat IC comparisons for regions in both the Arctic and the Antarctic are presented. The Landsat comparisons show that the overall algorithm accuracy under winter conditions is 7 pct. on average with 4 pct. negative bias. Next, high resolution active and passive microwave image mosaics from coordinated NASA and Navy aircraft underflights over regions of the Beaufort and Chukchi seas in March 1988 were used to show that the algorithm multiyear IC accuracy is 11 pct. on average with a positive bias of 12 pct. Ice edge crossings of the Bering Sea by the NASA DC-8 aircraft were used to show that the SSM/I 15 pct. ice concentration contour corresponds best to the location of the initial bands at the ice edge. Finally, a summary of results and recommendations for improving the SIC retrievals from spaceborne radiometers are provided

    Determinants of Newspaper Circulation

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    This study offers a new approach to the problem of time-series studies and attempts to set up a model to account for the growth in demand for daily newspapers Using U S data on a state-by-state basis for 1850 to 1970, we have used a marketing approach What conditions were necessary for the survival of a daily newspaper? What conditions were conducive to consolidation? What conditions were a barrier to the adoption of social and technological innovation? The data were grouped into geographic and social regions for analysis, using a special case of generalized least squares Independent variables included price as a proportion of per-capita income, percentage of the work force in nonagricultural labor, education, voting, and urbanization. Price proved the most powerful predictor Corrected R2s range from 22636 (m regions where newspaper growth took place very early or late in the period) to 67543 in the Midwest and Southwest The model will be applied to data from the industrialized countries of Western Europe in later workPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67057/2/10.1177_009365028000700101.pd

    An analysis of trends, frequencies and factors influencing the development of resistance to phosphine in the red flour beetle Tribolium castaneum (Herbst) in Australia

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    Although resistance to phosphine, the key disinfestant used worldwide in the stored grain environment has been an ongoing industry issue, studies on its trend over large geographic region and over long period of time is very limited. In this study, we critically analysed 20 years' phosphine resistance diagnosis data for the red flour beetle Tribolium castaneum (Herbst) stored in the Australian Grain Insect Resistance Database. Resistance diagnosis on a staggering 6336 samples, along with information on storage types and treatment history was interrogated to establish trends and frequencies of resistance development in this species and factors that may have contributed towards these resistance occurences. Using descriptive statistics, linear and trend analysis and a well established Bayesian hurdle model, we determined that strong resistance in T. castaneum was significantly more prevalent in quarantine intereceptions than in central storages and on farms. The strong resistance incidences had been confined to eastern states of Queensland, New South Wales, Victoria and South Australia, whereas it is yet to be detected in the state of Western Australia. We could not establish any significant correlation between the strong resistance development and any commodity or treatments. After an initial increasing trend in incidences since the first detection of strong resistance in 1997 in this species, the frequency was stabilised during 2001–08; after which there had been an upward trend since 2009 till the last survey in 2013. The conclusions derived from this analyses highlighted the importance of a resistance monitoring program with relevant information being used in Australia as the basis for ongoing and future phosphine resistance management strategies. This research may also proved valuable towards devising similar strategies in overseas countries with phosphine resistance problems

    Non-polar (11-20) InGaN quantum dots with short exciton lifetimes grown by metal-organic vapor phase epitaxy

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    We report on the optical characterization of non-polar a-plane InGaN quantum dots (QDs) grown by metal-organic vapor phase epitaxy using a short nitrogen anneal treatment at the growth temperature. Spatial and spectral mapping of sub-surface QDs have been achieved by cathodoluminescence at 8 K. Microphotoluminescence studies of the QDs reveal resolution limited sharp peaks with typical linewidth of 1 meV at 4.2 K. Time-resolved photoluminescence studies suggest the excitons in these QDs have a typical lifetime of 538 ps, much shorter than that of the c-plane QDs, which is strong evidence of the significant suppression of the internal electric fields.Comment: 4 figures, submitte

    Supraclavicular decompression for neurogenic thoracic outlet syndrome in adolescent and adult populations

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    ObjectiveThis study was conducted to better define clinical results and understand factors determining responsiveness to surgical treatment for neurogenic thoracic outlet syndrome (NTOS) in adolescent and adult populations.MethodsA retrospective review was conducted for 189 patients with disabling NTOS who underwent primary supraclavicular decompression (scalenectomy, brachial plexus neurolysis and first rib resection, with or without pectoralis minor tenotomy) from April 2008 to December 2010. Clinical characteristics were compared between 35 adolescent patients (aged <21 years) and 154 adults (aged >21 years). Functional outcome measures were assessed before surgery and at 3- and 6-month follow-up using a composite NTOS Index combining the Disabilities of the Arm, Shoulder and Hand (DASH) survey, the Cervical-Brachial Symptom Questionnaire (CBSQ), and a 10-point visual analog scale (VAS) for pain.ResultsAdolescent and adult patients were not significantly different with respect to sex (overall 72.5% female), side affected (58.7% right, 60.3% dominant limb), bony anomalies (23.3%), previous injury (55.6%), coexisting pain disorders (11.1%), and positive responses to scalene muscle anesthetic blocks (95.6%). Compared with adults, adolescent patients had a significantly (P < .05) lower incidence of depression (11.4% vs 41.6%), motor vehicle injury (5.7% vs 20.1%), previous operations (11.4% vs 29.9%), preoperative use of opiate medications (17.1% vs 44.8%), and symptom duration >2 years (24.2% vs 50.0%). Mean preoperative NTOS Index (scale 0-100) was significantly lower in adolescent vs adult patients (46.5 ± 3.6 vs 58.5 ± 1.7; P = .009), and hospital length of stay was 4.4 ± 0.2 vs 4.9 ± 0.1 days (P = .03), but the rate of postoperative complications was no different (overall, 4.2%). Although both groups exhibited significant improvement in functional outcome measures at 3 and 6 months, adolescent patients had significantly lower NTOS Index (10.4 ± 3.1 vs 39.3 ± 3.3; P < .001) and use of opiate medications (11.4% vs 47.4%; P < .001) compared with adults.ConclusionsAdolescents undergoing supraclavicular decompression for NTOS had more favorable preoperative characteristics and enhanced 3-month and 6-month functional outcomes than adults. Further study is needed to delineate the age-dependent and independent factors that promote optimal surgical outcomes for NTOS
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