58 research outputs found

    Peak grain forecasts for the US High Plains amid withering waters

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    ACKNOWLEDGMENTS. This paper stems from discussions during the Ettersburg Ecohydrology Workshop in Germany (October 2018), with the corresponding manuscript preparation ensuing in subsequent months. The workshop was funded by the UNIDEL Foundation, Inc. and the University of Delaware. Accordingly, partial support for this paper derived from funding for the workshop. A.M. was supported by the US NSF (Grants NSF-AGS-1644382 and NSF-IOS-175489).Peer reviewedPublisher PD

    Coronal Dimmings and the Early Phase of a CME Observed with STEREO and Hinode/EIS

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    We investigate the early phase of the 13 February 2009 coronal mass ejection (CME). Observations with the twin STEREO spacecraft in quadrature allow us to compare for the first time in one and the same event the temporal evolution of coronal EUV dimmings, observed simultaneously on-disk and above the limb. We find that these dimmings are synchronized and appear during the impulsive acceleration phase of the CME, with the highest EUV intensity drop occurring a few minutes after the maximum CME acceleration. During the propagation phase two confined, bipolar dimming regions, appearing near the footpoints of a pre-flare sigmoid structure, show an apparent migration away from the site of the CME-associated flare. Additionally, they rotate around the 'center' of the flare site, i.e., the configuration of the dimmings exhibits the same 'sheared-to-potential' evolution as the postflare loops. We conclude that the motion pattern of the twin dimmings reflects not only the eruption of the flux rope, but also the ensuing stretching of the overlying arcade. Finally, we find that: (1) the global-scale dimmings, expanding from the source region of the eruption, propagate with a speed similar to that of the leaving CME front; (2) the mass loss occurs mainly during the period of strongest CME acceleration. Two hours after the eruption Hinode/EIS observations show no substantial plasma outflow, originating from the 'open' field twin dimming regions.Comment: accepted for publication in Solar Physic

    Microflares and the Statistics of X-ray Flares

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    This review surveys the statistics of solar X-ray flares, emphasising the new views that RHESSI has given us of the weaker events (the microflares). The new data reveal that these microflares strongly resemble more energetic events in most respects; they occur solely within active regions and exhibit high-temperature/nonthermal emissions in approximately the same proportion as major events. We discuss the distributions of flare parameters (e.g., peak flux) and how these parameters correlate, for instance via the Neupert effect. We also highlight the systematic biases involved in intercomparing data representing many decades of event magnitude. The intermittency of the flare/microflare occurrence, both in space and in time, argues that these discrete events do not explain general coronal heating, either in active regions or in the quiet Sun.Comment: To be published in Space Science Reviews (2011

    Global Properties of Solar Flares

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    An Observational Overview of Solar Flares

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    We present an overview of solar flares and associated phenomena, drawing upon a wide range of observational data primarily from the RHESSI era. Following an introductory discussion and overview of the status of observational capabilities, the article is split into topical sections which deal with different areas of flare phenomena (footpoints and ribbons, coronal sources, relationship to coronal mass ejections) and their interconnections. We also discuss flare soft X-ray spectroscopy and the energetics of the process. The emphasis is to describe the observations from multiple points of view, while bearing in mind the models that link them to each other and to theory. The present theoretical and observational understanding of solar flares is far from complete, so we conclude with a brief discussion of models, and a list of missing but important observations.Comment: This is an article for a monograph on the physics of solar flares, inspired by RHESSI observations. The individual articles are to appear in Space Science Reviews (2011

    Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

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    Rainfall interception loss by forest canopies. In: Forest Hydrology and Biogeochemistry: Synthesis of Past Research and Future Directions

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    Abstract Background Evaluations on different aspects of the performance of public hospitals in China have been conducted, usually based on indicators developed by literature review and expert suggestions. The patient perspective was not always considered. This study aims to identify what patients care most about in China’s public hospitals exclusively from a patient perspective. Methods A mix of stratified sampling and typical sampling was used to select 15 public hospitals in Jiangsu Province of China. In each sampled hospital, a convenient sample of six outpatients and six inpatients was selected to conduct face-to-face individual interviews. An interview guide consisting of six open-ended questions was designed. Donabedian’s quality of care framework was applied to categorize themes and subthemes, which were generated from patients’ interviews by using the conventional content analysis approach. Frequencies of themes and subthemes were counted. Results Nine key themes were identified regarding patients’ concerns about hospital care, which were environment and facilities, professional competence, hospital reputation, and morals of medical staff in the “structure” category of Donabedian’s framework, caring attitudes and emotional support, medical costs, communication and information, and efficiency and coordination of care in the “process” category, and health outcomes in the “outcome” category. Conclusions This study has identified and prioritized the aspects that patients care most about in China’s public hospitals in Jiangsu Province exclusively from a patient perspective. A measurement tool of patient-reported experiences in public hospitals could be built based on this study. Efforts should be made to represent the patient perspective to further improve the reform of public hospitals in China

    Continued Investigation of Short Contact Time Reactors for Regeneratively-Cooled Hypersonic Vehicles

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