1,989 research outputs found
Two approaches for effective modelling of rain-rate time-series for radiocommunication system simulations
The paper presents a model which allows to synthetically generate rain rate time-series for a fixed location. Rain rate time-series are very much correlated with signal attenuation in Ka band and above and, thus, enable to realistically simulate propagation effects on Earth-satellite links. The model presented are based on Markov chains
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Ionising radiation exposure from medical imaging – A review of Patient's (un) awareness
Introduction: Medical imaging is the main source of artificial radiation exposure. Evidence, however, suggests that patients are poorly informed about radiation exposure when attending diagnostic scans. This review provides an overview of published literature with a focus on nuclear medicine patients on the level of awareness of radiation exposure from diagnostic imaging. Methods: A review of available literature on awareness, knowledge and perception of ionising radiation in medical imaging was conducted. Articles that met the inclusion criteria were subjected to critical appraisal using the Mixed Methods Appraisal Tool. Results: 140 articles identified and screened for eligibility, 24 critically assessed and 4 studies included in synthesis. All studies demonstrated that patients were generally lacking awareness about radiation exposure and highlighted a lack of communication between healthcare professionals and patients with respect to radiation exposure. Conclusion: Studies demonstrate a need to better inform patients about their radiation exposure, and further studies focusing on nuclear medicine patients are particularly warranted. Implications for practice: Adequate and accurate information is crucial to ensure the principle of informed consent is present
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Radiation exposure awareness from patients undergoing nuclear medicine diagnostic 99mTc-MDP bone scans and 2-deoxy-2-(18F) fluoro-D-glucose PET/computed tomography scans
INTRODUCTION: Medical imaging is on average the largest source of artificial radiation exposure worldwide. This study seeks to understand patient's awareness of radiation exposure derived from nuclear medicine diagnostic scans and assess if current information provided by leaflets is adequate.
METHODS: Single-centre cross-sectional questionnaire study applied to bone scan and FDG PET/computed tomography patients, at a nuclear medicine and PET/computed tomography department over a 15-week period in 2018. Questionnaires on dose comparators were designed in collaboration with patients, public, and experts in radiation exposure. Qualitative data were analysed using thematic analysis and quantitative data using SPSS (V. 24).
RESULTS: A total of 102 questionnaires were completed (bone scan = 50; FDG PET/computed tomography = 52). Across both groups, 33/102 (32.4%) patients reported having a reasonable understanding of nuclear medicine and 21/102 (20.6%) reported a reasonable knowledge of ionising radiations. When asked to compare the exposure dose of respective scans with common comparators 8/50 (16%) of bone scan patients and 11/52 (21.2%) FDG PET/computed tomography answered correctly. On leaflet information, 15/85 (17.6%) patients reported the leaflets do not provide enough information on radiation exposure and of these 10/15 (66.7%) commented the leaflets should incorporate more information on radiation exposure dose.
CONCLUSION: More observational and qualitative studies in collaboration with patients are warranted to evaluate patients' understanding and preferences in communication of radiation exposure from nuclear medicine imaging. This will ensure communication tools and guidelines developed to comply with ionising radiation (medical exposure) regulation 2017 are according to patients needs and preferences
The tropospheric gas composition of Jupiter's north equatorial belt (NH3, PH3, CH3D, GeH4, H2O) and the Jovian D/H isotropic ratio
The gas composition of the troposphere of Jupiter in the clearest regions of the North Equatorial Belt (NEB) was derived from the Voyager 1 IRIS data. The infrared spectrum for this homogeneous cloud free region was modeled to infer altitude profiles for NH3, PH3, GeH4 and H2O. The Profiles for NH3 and PH3 were found to be depleted in the upper troposphere but otherwise in agreement with their solar values at the 1 bar level. The mole fraction for CH3D was determined to be 3.5(+1.0 or -1.3) x 10 to the minus 7th power. The GeH4 mole fraction of 7+ or -2 x 10 to the minus 10th power at the 2 to 3 bar level is a factor of 10 lower than the solar value. The H2O mole fraction is approximately 1 x 0.00001 at the 2.5 bar level and is increasing to approximately 3 x 0.00001 at 4 bars where it is a factor of 30 lower than solar. Using IRIS infrared values for the mole fractions of CH3D and CH4 a value of D/H = 3.6(+1.0 or -1.4)x 0.00001 is derived. Assuming this Jovian D/H ratio is representative of the protosolar nebula, and correcting for chemical galactic evolution, yields a value of 5.5 - 9.0 x 0.00001 for the primordial D/H ratio and an upper limit of 1.8 to 2.4 x 10 to the minus 31st power cu cm for the present day baryon density
Assessment of inoculation methods for screening black alder resistance to Phytophthora ×alni
International audienceIdentification of resistance to Phytophthora ×alni could provide the basis for a management strategy against alder decline in riparian ecosystems in Europe. Our objectives were to test methods to evaluate the resistance of riparian alders to the disease, and to screen alder genotypes for resistance. P. ×alni isolates were compared for their stability in collection, aggressiveness (lesion length on stem) and sporulation capacity (sporangia). While no difference of lesion lengths was found between P. ×alni isolates, sporangia production was dependent on isolate, highlighting the need to select carefully isolates for inoculation methods dealing with zoospores suspension. Inoculation tests carried out at different periods of the year revealed a seasonal change in susceptibility to the disease, with the period from June to September being the most efficient for inoculation tests. Stem-wounded inoculations tests carried out on excised shoots were found unreliable for evaluating the level of resistance of alder genotypes to P. ×alni infection, with divergent results between two successive years or between two inoculation periods during the same year. In contrast, a method which mimics the natural conditions of infection based on flooding of rooted cuttings in artificially infected river water was found promising. Another method based on the inoculation of foliated terminal shoots with zoospore suspensions was found to be repeatable and could be used for high throughput analyses. Altogether, the results show a continuous resistance response from highly susceptible to moderately resistant genotypes. This suggests that breeding might be a useful strategy to manage alder decline caused by P. ×alni
The Rotation of Sub-Populations in omega Centauri
We present the first result of the Ital-FLAMES survey of red giant branch
(RGB) stars in omega Cen. Radial velocities with a precision of ~0.5 km/s are
presented for 650 members of omega Cen observed with FLAMES-Giraffe at the Very
Large Telescope. We found that stars belonging to the metal -poor (RGB-MP),
metal-intemediate (RGB-MInt) and metal-rich (RGB-a) sub -populations of Omega
Cen are all compatible with having the same rotational pattern. Our results
appear to contradict past findings by Norris et al., who could not detect any
rotational signature for metal -rich stars. The slightly higher precision of
the present measurements and the much larger sample size, especially for the
metal-richer stars, appear as the most likely explanation for this discrepancy.
The result presented here weakens the body of evidence in favour of a merger
event in the past history of omega Cen.Comment: 5 pages, 3 fiures, electronic table can be obtained from E. Pancino.
Accepted for publication in ApJ Letter
Améliorer la connaissance du patrimoine en France pour une gestion durable du patrimoine des réseaux d'eau potable
IWA World Water Congress & Exhibition, Tokyo, JPN, 16-/09/2018 - 21/09/2018International audienceWith the aim of improving the implementation and evaluation of public policy in France relating to sustainable drinking water asset management (regulation at national level and subsidies at watershed level) the French Ministry of Ecology asked Irstea, a state research body, to create an ongoing system to manage technical and financial knowledge relating to drinking water network assets. In this study we develop a statistical approach to model pipe length by category, based on the geographical characteristics of the territory in which they are installed. Multivariate models including road length have been found to be pertinent. This technical analysis is accompanied by a study of asset values and renewal costs, based on a typology of water suppliers and an examination of economic and financial ratios. A number of disparities between territories are highlighted
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