222 research outputs found

    Episodic Occurrence of Field‐Aligned Energetic Ions on the Dayside

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    The tens of kiloelectron volt ions observed in the ring current region at L ~ 3–7 generally have pancake pitch angle distributions, that is, peaked at 90°. However, in this study, by using the Van Allen Probe observations on the dayside, unexpectedly, we have found that about 5% time, protons with energies of ~30 to 50 keV show two distinct populations, having an additional field‐aligned population overlapping with the original pancake population. The newly appearing field‐aligned populations have higher occurrence rates at ~12–16 magnetic local time during geomagnetically active times. In particular, we have studied eight such events in detail and found that the source regions are located around 12 to 18 magnetic local time which coincides with our statistical result. Based on the ionospheric and geosynchronous observations, it is suggested that these energetic ions with field‐aligned pitch angle distributions probably are accelerated near postnoon in association with ionospheric disturbances that are triggered by tail injections.Plain Language SummaryProtons of different sources have different pitch angle distributions (PADs). For example, warm plasma cloak protons, which come directly from the ionosphere, have field‐aligned PADs, while ring current protons that generally originate from tail plasma sheet have pancake‐shaped PADs. In this study, unexpectedly, we have found that about 5% of the time on the dayside, protons of ring current energies show two distinct populations according to their PADs: higher fluxes of field‐aligned populations overlapping with the original pancake populations. The newly appeared field‐aligned populations have higher occurrence rates at ~12–16 magnetic local time during geomagnetically active times. In order to find the mechanism that generates these field‐aligned energetic proton populations, we have studied eight such events in detail by using the low‐altitude DMSP, POES satellites, and the NOAA‐LANL satellite at the geosynchronous orbit. The results imply that these energetic ions with field‐aligned PADs probably are accelerated by ionospheric disturbances that are triggered by tail injections. These results provide evidence of another possibly important source of the ring current ions.Key PointsWe have found that about 5% of the time on the dayside, protons with energies of ~30 to 50 keV have strong field‐aligned PADsThe field‐aligned PADs have higher occurrence rates at ~12‐16 MLT during geomagnetically active timesThese energetic field‐aligned ions possibly are accelerated by ionospheric disturbances triggered by tail injectionsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153687/1/grl60102_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153687/2/grl60102.pd

    Developing and enhancing biodiversity monitoring programmes: a collaborative assessment of priorities

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    1.Biodiversity is changing at unprecedented rates, and it is increasingly important that these changes are quantified through monitoring programmes. Previous recommendations for developing or enhancing these programmes focus either on the end goals, that is the intended use of the data, or on how these goals are achieved, for example through volunteer involvement in citizen science, but not both. These recommendations are rarely prioritized. 2.We used a collaborative approach, involving 52 experts in biodiversity monitoring in the UK, to develop a list of attributes of relevance to any biodiversity monitoring programme and to order these attributes by their priority. We also ranked the attributes according to their importance in monitoring biodiversity in the UK. Experts involved included data users, funders, programme organizers and participants in data collection. They covered expertise in a wide range of taxa. 3.We developed a final list of 25 attributes of biodiversity monitoring schemes, ordered from the most elemental (those essential for monitoring schemes; e.g. articulate the objectives and gain sufficient participants) to the most aspirational (e.g. electronic data capture in the field, reporting change annually). This ordered list is a practical framework which can be used to support the development of monitoring programmes. 4.People's ranking of attributes revealed a difference between those who considered attributes with benefits to end users to be most important (e.g. people from governmental organizations) and those who considered attributes with greatest benefit to participants to be most important (e.g. people involved with volunteer biological recording schemes). This reveals a distinction between focussing on aims and the pragmatism in achieving those aims. 5.Synthesis and applications. The ordered list of attributes developed in this study will assist in prioritizing resources to develop biodiversity monitoring programmes (including citizen science). The potential conflict between end users of data and participants in data collection that we discovered should be addressed by involving the diversity of stakeholders at all stages of programme development. This will maximize the chance of successfully achieving the goals of biodiversity monitoring programmes

    Using paired serology and surveillance data to quantify dengue transmission and control during a large outbreak in Fiji.

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    Dengue is a major health burden, but it can be challenging to examine transmission and evaluate control measures because outbreaks depend on multiple factors, including human population structure, prior immunity and climate. We combined population-representative paired sera collected before and after the 2013/14 dengue-3 outbreak in Fiji with surveillance data to determine how such factors influence transmission and control in island settings. Our results suggested the 10-19 year-old age group had the highest risk of infection, but we did not find strong evidence that other demographic or environmental risk factors were linked to seroconversion. A mathematical model jointly fitted to surveillance and serological data suggested that herd immunity and seasonally varying transmission could not explain observed dynamics. However, the model showed evidence of an additional reduction in transmission coinciding with a vector clean-up campaign, which may have contributed to the decline in cases in the later stages of the outbreak

    UKIRT under new management: status and plans

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    The United Kingdom Infrared Telescope (UKIRT) observatory has been transferred to the ownership of the University of Hawaii (UH) and is now being managed by UH. We have established partnerships with several organizations to utilize the UKIRT for science projects and to support its operation. Our main partners are the U.S. Naval Observatory (USNO), the East Asian Observatory (EAO), and the UKIRT microlensing team (JPL/IPAC/OSU/Vanderbilt). The USNO is working on deep northern hemisphere surveys in the H and K bands and the UKIRT microlensing team is running a monitoring campaign of the Galactic bulge. EAO, UH, and USNO have individual P.I. research programs. Most of the observations are using the Wide Field Camera (WFCAM), but the older suite of cassegrain instruments are still fully operational. Data processing and archiving continue to be done CASU and WSA in the UK. We are working on a concept to upgrade the WFCAM with new larger infrared detector arrays for substantially improved survey efficiency

    Comparison of alternative evidence summary and presentation formats in clinical guideline development: a mixed-method study.

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    BACKGROUND: Best formats for summarising and presenting evidence for use in clinical guideline development remain less well defined. We aimed to assess the effectiveness of different evidence summary formats to address this gap. METHODS: Healthcare professionals attending a one-week Kenyan, national guideline development workshop were randomly allocated to receive evidence packaged in three different formats: systematic reviews (SRs) alone, systematic reviews with summary-of-findings tables, and 'graded-entry' formats (a 'front-end' summary and a contextually framed narrative report plus the SR). The influence of format on the proportion of correct responses to key clinical questions, the primary outcome, was assessed using a written test. The secondary outcome was a composite endpoint, measured on a 5-point scale, of the clarity of presentation and ease of locating the quality of evidence for critical neonatal outcomes. Interviews conducted within two months following completion of trial data collection explored panel members' views on the evidence summary formats and experiences with appraisal and use of research information. RESULTS: 65 (93%) of 70 participants completed questions on the prespecified outcome measures. There were no differences between groups in the odds of correct responses to key clinical questions. 'Graded-entry' formats were associated with a higher mean composite score for clarity and accessibility of information about the quality of evidence for critical neonatal outcomes compared to systematic reviews alone (adjusted mean difference 0.52, 95% CI 0.06 to 0.99). There was no difference in the mean composite score between SR with SoF tables and SR alone. Findings from interviews with 16 panelists indicated that short narrative evidence reports were preferred for the improved clarity of information presentation and ease of use. CONCLUSIONS: Our findings suggest that 'graded-entry' evidence summary formats may improve clarity and accessibility of research evidence in clinical guideline development. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN05154264

    A systematic review of the evidence for single stage and two stage revision of infected knee replacement

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    BACKGROUND: Periprosthetic infection about the knee is a devastating complication that may affect between 1% and 5% of knee replacement. With over 79 000 knee replacements being implanted each year in the UK, periprosthetic infection (PJI) is set to become an important burden of disease and cost to the healthcare economy. One of the important controversies in treatment of PJI is whether a single stage revision operation is superior to a two-stage procedure. This study sought to systematically evaluate the published evidence to determine which technique had lowest reinfection rates. METHODS: A systematic review of the literature was undertaken using the MEDLINE and EMBASE databases with the aim to identify existing studies that present the outcomes of each surgical technique. Reinfection rate was the primary outcome measure. Studies of specific subsets of patients such as resistant organisms were excluded. RESULTS: 63 studies were identified that met the inclusion criteria. The majority of which (58) were reports of two-stage revision. Reinfection rated varied between 0% and 41% in two-stage studies, and 0% and 11% in single stage studies. No clinical trials were identified and the majority of studies were observational studies. CONCLUSIONS: Evidence for both one-stage and two-stage revision is largely of low quality. The evidence basis for two-stage revision is significantly larger, and further work into direct comparison between the two techniques should be undertaken as a priority

    Patterns of Breast Magnetic Resonance Imaging Use in Community Practice

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    Breast magnetic resonance imaging (MRI) is increasingly used for breast cancer screening, diagnostic evaluation, and surveillance However, we lack data on national patterns of breast MRI use in community practice

    The Need for Laboratory Measurements and Ab Initio Studies to Aid Understanding of Exoplanetary Atmospheres

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    We are now on a clear trajectory for improvements in exoplanet observations that will revolutionize our ability to characterize their atmospheric structure, composition, and circulation, from gas giants to rocky planets. However, exoplanet atmospheric models capable of interpreting the upcoming observations are often limited by insufficiencies in the laboratory and theoretical data that serve as critical inputs to atmospheric physical and chemical tools. Here we provide an up-to-date and condensed description of areas where laboratory and/or ab initio investigations could fill critical gaps in our ability to model exoplanet atmospheric opacities, clouds, and chemistry, building off a larger 2016 white paper, and endorsed by the NAS Exoplanet Science Strategy report. Now is the ideal time for progress in these areas, but this progress requires better access to, understanding of, and training in the production of spectroscopic data as well as a better insight into chemical reaction kinetics both thermal and radiation-induced at a broad range of temperatures. Given that most published efforts have emphasized relatively Earth-like conditions, we can expect significant and enlightening discoveries as emphasis moves to the exotic atmospheres of exoplanets.Comment: Submitted as an Astro2020 Science White Pape
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