213 research outputs found

    Hardening electronic devices against very high total dose radiation environments

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    The possibilities and limitations of hardening silicon semiconductor devices to the high neutron and gamma radiation levels and greater than 10 to the eighth power rads required for the NERVA nuclear engine development are discussed. A comparison is made of the high dose neutron and gamma hardening potential of bipolar, metal insulator semiconductors and junction field effect transistors. Experimental data is presented on device degradation for the high neutron and gamma doses. Previous data and comparisons indicate that the JFET is much more immune to the combined neutron displacement and gamma ionizing effects than other transistor types. Experimental evidence is also presented which indicates that p channel MOS devices may be able to meet the requirements

    Silo construction

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    The value of the silo as a means of utilizing almost the entire corn plant and producing valuable feed has been thoroly demonstrated. Silage is an economical and desirable feed and it is highly desirable that the use of the silo be more generally adopted. The construction of silos has been for many years one of the principal lines of investigation followed by the Agricultural Engineering Section of the Iowa Agricultural Experiment Station. Results have been published in the following bulletins: No. 100, July, 1908, revised and republished July, 1909; No. 117, June, 1910, by J. B. Davidson and M. L. King, and No. 141, June, 1913, by J. B. Davidson. This new bulletin No. 189 is a revision of Bulletin No. 141. The Agricultural Engineering Section does not recommend any one type of silo above all others. It has been demonstrated by experience that a number of different types of silos will each give satisfactory service if properly constructed. It is well worth while for the silo builder to study the types and details of construction which will insure a reasonably permanent structure

    THE EFFECT OF NEAR-INTERFACE NETWORK STRAIN ON THE MOBILITY OF PROTONS IN Si02

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    35-word abstract Our data suggest a correlation between near-interface strain in SiOz and the ratio of fixed vs. mobile positive charge generated at the interface during forming gas annealing. A model based on firstprinciples quantum mechanical calculations supports this correlation

    Focused Ion Beam Fabrication

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    Contains summary of research program and reports on four research projects.Charles Stark Draper Laboratory (Contract DL-H-225270)Hughes Research LaboratoriesInternational Business Machines, Inc. (Contract 456614)Nippon Telegraph and Telephone, Inc.U.S. Navy - Office of Naval Research (Contract N00014-84-K-0073)U.S. Department of Defense (Contract MDA903-85-C-0215)Hitachi Central Research Laborator

    Focused Ion Beam Fabrication

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    Contains reports on five research projects.DARPA/Naval Electronic Systems Command (Contract MDA-903-85-C-0215)Charles Stark Draper Laboratory (Contract DL-H-261827)U.S. Navy - Office of Naval Research (Contract N00014-84-K-0073)Nippon Telephone and TelegraphHitachi Central Research Laborator

    Footprint of deepwater horizon blowout impact to deep-water coral communities

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    On April 20, 2010, the Deepwater Horizon (DWH) blowout occurred, releasing more oil than any accidental spill in history. Oil release continued for 87 d and much of the oil and gas remained in, or returned to, the deep sea. A coral community significantly impacted by the spill was discovered in late 2010 at 1,370 m depth. Here we describe the discovery of five previously unknown coral communities near the Macondo wellhead and show that at least two additional coral communities were impacted by the spill. Although the oil-containing flocullent material that was present on corals when the first impacted community was discovered was largely gone, a characteristic patchy covering of hydrozoans on dead portions of the skeleton allowed recognition of impacted colonies at the more recently discovered sites. One of these communities was 6 km south of the Macondowellhead and over 90% of the corals present showed the characteristic signs of recent impact. The other community, 22 km southeast of the wellhead between 1,850 and 1,950 m depth, was more lightly impacted. However, the discovery of this site considerably extends the distance from Macondo and depth range of significant impact to benthic macrofaunal communities. We also show that most known deep-water coral communities in the Gulf of Mexico do not appear to have been acutely impacted by the spill, although two of the newly discovered communities near thewellhead apparently not impacted by the spill have been impacted by deep-sea fishing operations

    Recommendations for a national agenda to substantially reduce cervical cancer

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    PURPOSE: Prophylactic human papillomavirus (HPV) vaccines and new HPV screening tests, combined with traditional Pap test screening, provide an unprecedented opportunity to greatly reduce cervical cancer in the USA. Despite these advances, thousands of women continue to be diagnosed with and die of this highly preventable disease each year. This paper describes the initiatives and recommendations of national cervical cancer experts toward preventing and possibly eliminating this disease. METHODS: In May 2011, Cervical Cancer-Free America, a national initiative, convened a cervical cancer summit in Washington, DC. Over 120 experts from the public and private sector met to develop a national agenda for reducing cervical cancer morbidity and mortality in the USA. RESULTS: Summit participants evaluated four broad challenges to reducing cervical cancer: (1) low use of HPV vaccines, (2) low use of cervical cancer screening, (3) screening errors, and (4) lack of continuity of care for women diagnosed with cervical cancer. The summit offered 12 concrete recommendations to guide future national and local efforts toward this goal. CONCLUSIONS: Cervical cancer incidence and mortality can be greatly reduced by better deploying existing methods and systems. The challenge lies in ensuring that the array of available prevention options are accessible and utilized by all age-appropriate women-particularly minority and underserved women who are disproportionately affected by this disease. The consensus was that cervical cancer can be greatly reduced and that prevention efforts can lead the way towards a dramatic reduction in this preventable disease in our country

    Assessing Syndromic Surveillance of Cardiovascular Outcomes from Emergency Department Chief Complaint Data in New York City

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    Prospective syndromic surveillance of emergency department visits has been used for near-real time tracking of communicable diseases to detect outbreaks or other unexpected disease clusters. The utility of syndromic surveillance for tracking cardiovascular events, which may be influenced by environmental factors and influenza, has not been evaluated. We developed and evaluated a method for tracking cardiovascular events using emergency department free-text chief complaints.There were three phases to our analysis. First we applied text processing algorithms based on sensitivity, specificity, and positive predictive value to chief complaint data reported by 11 New York City emergency departments for which ICD-9 discharge diagnosis codes were available. Second, the same algorithms were applied to data reported by a larger sample of 50 New York City emergency departments for which discharge diagnosis was unavailable. From this more complete data, we evaluated the consistency of temporal variation of cardiovascular syndromic events and hospitalizations from 76 New York City hospitals. Finally, we examined associations between particulate matter ≤2.5 µm (PM(2.5)), syndromic events, and hospitalizations. Sensitivity and positive predictive value were low for syndromic events, while specificity was high. Utilizing the larger sample of emergency departments, a strong day of week pattern and weak seasonal trend were observed for syndromic events and hospitalizations. These time-series were highly correlated after removing the day-of-week, holiday, and seasonal trends. The estimated percent excess risks in the cold season (October to March) were 1.9% (95% confidence interval (CI): 0.6, 3.2), 2.1% (95% CI: 0.9, 3.3), and 1.8% (95%CI: 0.5, 3.0) per same-day 10 µg/m(3) increase in PM(2.5) for cardiac-only syndromic data, cardiovascular syndromic data, and hospitalizations, respectively.Near real-time emergency department chief complaint data may be useful for timely surveillance of cardiovascular morbidity related to ambient air pollution and other environmental events
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