637,025 research outputs found

    Influence of plasma chemistry on oxygen triplets

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    The plasma chemistry of fluorocarbon-oxygen-argon discharges and its influence on prominent oxygen triplets are studied. The oxygen 777 triplet is very important for the measurement of atomic oxygen in low pressure plasmas, since the 777.417 nm spectral line is frequently used for actinometry. In this paper we identify changes in the individual 777 triplet lines arising from cascade effects from higher energy levels of oxygen, and from resonant energy transfer from energetic carbon atoms in carbon-rich plasmas. The lower energy levels of three oxygen triplets (544 nm, 616 nm, 645 nm) are the upper states of the 777 triplet. Increased emission intensity from the 544, 616, and 645 triplets result in changes to the relative intensity of the individual lines of the 777 triplet, and this can lead to errors in using the 777 triplet, e.g. for actinometry. Also, in operational conditions with strong carbon emission (around 601 nm), the relative intensity of the individual oxygen 777 lines is affected. The upper energy levels of these carbon lines is close to the oxygen 777 upper energy levels, suggesting that resonant energy transfer between the carbon and the oxygen is occurring. The experiments are performed in a commercial semiconductor dielectric etcher operating with dual rf frequencies of 2 MHz and 27 MHz. Pressure (13-19 Pa), rf power (200-1200 W), and gas mixtures (argon with addmixtures of 5-13% oxygen and C4F8) are typical in application to dielectric etching

    3D non-LTE line formation in the solar photosphere and the solar oxygen abundance

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    We study the formation of O I and OH spectral lines in three-dimensional hydrodynamic models of the solar photosphere. The line source function of the O I 777 nm triplet is allowed to depart from local thermodynamic equilibrium (LTE), within the two-level-atom approximation. Comparison with results from 1D models show that the 3D models alleviate, but do not remove, the discrepancy between the oxygen abundances reported from non-LTE work on the 777 nm triplet and from the [O I] 630 nm and OH lines. Results for the latter two could imply that the solar oxygen abundance is below 8.8 (lg(H) = 12). If this is confirmed, the discrepancy between theory and observation for the 777 nm triplet lines might fall within the range of errors in equivalent width measurements and f-values. The line source function of the 777 nm triplet in the 1.5D approximation is shown to differ insignificantly from the full 3D non-LTE result.Comment: 10 pages, uuencoded compressed PostScript file including figures, to appear in Astronomy & Astrophysics. Also available at ftp://www.astro.su.se/pub/da

    Infrared organic light emitting diodes using neodymium tris-(8-hydroxyquinoline)

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    Copyright 2000 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Journal of Applied Physics 88, 777 (2000) and may be found at

    Documents accompanying the Report of the Secretary of War

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    777-779 H.exdoc.133-2Annual Message to Congress with Documents. Pres. Pierce [746-748] Annual report of the Sec. of War (Serials 747 and 778); annual report of the Sec. of the Interior (Serials 746 and 777); annual report of the General Land Office (Serials 746 and 777); annual report of the CIA (Serials 746 and 777), including reports of Supts., agents, missions, and schools; etc.1854-11

    Implementing every child a writer

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    Ethics as a risk management strategy: the Australian experience

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    This article addresses the connection of ethics to risk management, and argues that there are compelling reasons to consider good ethical practice to be an essential part of such risk management. That connection has significant commercial outcomes, which include identifying potential problems, preventing fraud, the preservation of corporate reputation, and the mitigation of court penalties should any transgression arise. Information about the legal position, examples of cases, and arguments about the potential benefits of ethics are canvassed. The orientation of this article is essentially Australian. It is hoped that it may provide some insights of value to other countries

    Shrinking the Malaria Map: A Prospectus on Malaria Elimination

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    \ud Thirty-nine countries across the world are making progress toward malaria elimination. Some are committed to nationwide elimination, while others are pursuing spatially progressive elimination within their borders. Influential donor and multilateral organizations are supporting their goals of achieving malaria-free status. With elimination back on the global agenda, countries face a myriad of questions. Should they change their programs to eliminate rather than control malaria? What tools are available? What policies need to be put into place? How will they benefit from elimination? Unfortunately, answers to these questions, and resources for agencies and country program managers considering or pursuing elimination, are scarce. The 39 eliminating countries are all positioned along the endemic margins of the disease, yet they naturally experience a variety of country characteristics and epidemiologies that make their malaria situations different from one another. The Malaria Elimination Group (MEG) and this Prospectus recognize\ud that there is no single solution, strategy, or time line that will be appropriate for every country, and each is encouraged to initiate a comprehensive evaluation of its readiness and strategy for elimination. The Prospectus is designed to guide countries in conducting these assessments. The Prospectus provides detailed and informed discussion on the practical means of achieving and sustaining zero transmission. It is designed as a road map, providing direction and options from which to choose an appropriate path. As on all maps, the destination is clearly marked, but the possible routes to reach it are numerous. The Prospectus is divided into two sections: Section 1 Eliminating Malaria comprises four chapters covering the strategic components important to the periods before, during, and after an elimination program. Section 2 Tools for the Job, comprises six chapters that outline basic information about how interventions in an elimination program will be different from those in a control setting. Chapter 1, Making the Decision, evaluates the issues that a country should consider when deciding whether or not to eliminate malaria. The chapter begins with a discussion about the quantitative and qualitative benefits that a country could expect from eliminating malaria and then recommends a thorough feasibility assessment. The feasibility assessment is based on three major components: operational, technical, and financial feasibility. Cross-border and regional collaboration is a key subject in this chapter. Chapter 2, Getting to Zero, describes changes that programs must consider when moving from sustained control to an elimination goal. The key strategic issues that must be addressed are considered, including supply chains, surveillance systems, intersectoral collaboration, political will, and legislative framework. Cross-border collaboration is again a key component in Getting to Zero. Chapter 3, Holding the Line, provides recommendations on how to conduct an assessment of two key factors that will affect preventing the reemergence of malaria once transmission is interrupted: outbreak risk and importation risk. The chapter emphasizes the need for a strong surveillance system in order to prevent and, if necessary, respond to imported cases. Chapter 4, Financing Elimination, reviews the cost-effectiveness of elimination as compared with sustained control and then presents the costs of selected elimination programs as examples. It evaluates four innovative financing mechanisms that must support elimination, emphasizing the need for predictable and stable financing. Case studies from Swaziland and two provinces in China are provided. Chapter 5, Understanding Malaria, considers malaria from the point of view of elimination and provides a concise overview of the current burden of the disease, malaria transmission, and the available interventions that can be used in an elimination program. Chapter 6, Learning from History, extracts important lessons from the Global Malaria Eradication Program and analyzes some elimination efforts that were successful and some that were unsuccessful. The chapter also reviews how the malaria map has been shrinking since 1900. xiv A Prosp ectus on Mala ria Elimi natio n\ud Chapter 7, Measuring Malaria for Elimination, provides a precise language for discussing malaria and gives the elimination discussion a quantitative structure. The chapter also describes the role of epidemiological theory and mathematical modeling in defining and updating an elimination agenda for malaria. Chapter 8, Killing the Parasite, outlines the importance of case detection and management in an elimination setting. Options for diagnosis, the hidden challenge of Plasmodium vivax in an elimination setting, and the impact of immunity are all discussed. Chapter 9, Suppressing the Vector, explores vector control, a necessary element of any malaria program. It considers optimal methods available to interrupt transmission and discusses potential changes, such as insecticide resistance, that may affect elimination efforts. Chapter 10, Identifying the Gaps — What We Need to Know, reviews the gaps in our understanding of what is required for elimination. The chapter outlines a short-term research agenda with a focus on the operational needs that countries are facing today. The Prospectus reviews the operational, technical, and financial feasibility for those working on the front lines and considers whether, when, and how to eliminate malaria. A companion document, A Guide on Malaria Elimination for Policy Makers, is provided for those countries or agencies whose responsibility is primarily to make the policy decisions on whether to pursue or support a malaria elimination strategy. The Guide is available at www.malaria eliminationgroup.org
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