Errors and uncertainty in radar estimates of precipitation result both from errors in the basic measurement of reflectivity and from attempts to relate this to the precipitation falling at the ground. If radar data are to be used to their full potential, it is essential that effective measures are taken to mitigate these problems. The automatic processing of radar data that forms part of the UK Met. Office's Nimrod system addresses a number of specific sources of error. These include the identification and removal of spurious echoes resulting from anomalous propagation of the radar beam, errors resulting from variations in the vertical profile of reflectivity and radar sensitivity errors. Routine verification of the surface precipitation estimates has been undertaken, largely through comparison with rain gauge observations, over a range of timescales, which has allowed the benefits of the quality control and correction processes to be quantified. Although the improvement derived varies according to the dominant synoptic situation, an average reduction in the root‐mean‐square difference between gauge and radar data of 30% can be achieved. Copyright © 2000 Royal Meteorological Society
ObjectiveThe speech, spatial, and qualities of hearing questionnaire (SSQ) is a self-report test of auditory disability. The 49 items ask how well a listener would do in many complex listening situations illustrative of real life. The scores on the items are often combined into the three main sections or into 10 pragmatic subscales. We report here a factor analysis of the SSQ that we conducted to further investigate its statistical properties and to determine its structure.DesignStatistical factor analysis of questionnaire data, using parallel analysis to determine the number of factors to retain, oblique rotation of factors, and a bootstrap method to estimate the confidence intervals.Study sample1220 people who have attended MRC IHR over the last decade.ResultsWe found three clear factors, essentially corresponding to the three main sections of the SSQ. They are termed “speech understanding”, “spatial perception”, and “clarity, separation, and identification”. Thirty-five of the SSQ questions were included in the three factors. There was partial evidence for a fourth factor, “effort and concentration”, representing two more questions.ConclusionsThese results aid in the interpretation and application of the SSQ and indicate potential methods for generating average scores.
The use of precipitation estimates from weather radar for hydrological applications has been limited by the quantitative accuracy, reliability and resolution. The adoption of a more centralised approach to radar data processing, upgrades to telecommunications links and the installation of additional radars in the UK weather radar network have enabled some of these limitations to be addressed. The development of more flexible product generation software, which more fully exploits the resolution of the radar measured reflectivity, now provides for the mapping of precipitation on scales of 1 km and even below, thus approaching the resolution requirements for applications in urban hydrology. This paper describes the methods by which these high-resolution precipitation products are now generated. Illustrations of the products are given and their use in predicting flow using an urban drainage model is demonstrated. Issues affecting data quality, and the advantages and disadvantages of using radar products at high resolution are discussed.
Objective-Sleep-disordered breathing describes a spectrum of upper airway obstruction in sleep from simple primary snoring, estimated to affect 10% of preschool children, to the syndrome of obstructive sleep apnea. Emerging evidence has challenged previous assumptions that primary snoring is benign. A recent report identified reduced attention and higher levels of social problems and anxiety/depressive symptoms in snoring children compared with controls. Uncertainty persists regarding clinical thresholds for medical or surgical intervention in sleep-disordered breathing, underlining the need to better understand the pathophysiology of this condition. Adults with sleepdisordered breathing have an increased risk of cerebrovascular disease independent of atherosclerotic risk factors. There has been little focus on cerebrovascular function in children with sleep-disordered breathing, although this would seem an important line of investigation, because studies have identified abnormalities of the systemic vasculature. Raised cerebral blood flow velocities on transcranial Doppler, compatible with raised blood flow and/or vascular narrowing, are associated with neuropsychological deficits in children with sickle cell disease, a condition in which sleepdisordered breathing is common. We hypothesized that there would be cerebral blood flow velocity differences in sleep-disordered breathing children without sickle cell disease that might contribute to the association with neuropsychological deficits.Design-Thirty-one snoring children aged 3 to 7 years were recruited from adenotonsillectomy waiting lists, and 17 control children were identified through a local Sunday school or as siblings of cases. Children with craniofacial abnormalities, neuromuscular disorders, moderate or severe learning disabilities, chronic respiratory/cardiac conditions, or allergic rhinitis were excluded. Severity of sleep-disordered breathing in snoring children was categorized by attended polysomnography. Weight, height, and head circumference were measured in all of the children. BMI and occipitofrontal circumference z scores were computed. Resting systolic and diastolic blood Address correspondence to Catherine M. Hill, BM, MSc, MRCP, FRCPCH, University of Southampton-Child Health, Mail Point 803, Southampton General Hospital, Southampton, Hampshire SO16 6YD, United Kingdom. Email: cmh2@soton.ac.uk The authors have indicated they have no financial relationships relevant to this article to disclose.Drs Hill and Hogan contributed equally to this work and share first authorship. NIH Public Access Author ManuscriptPediatrics. Author manuscript; available in PMC 2007 October 1. Published in final edited form as:Pediatrics. 2006 October ; 118(4): e1100-e1108. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript pressure were obtained. Both sleep-disordered breathing children and the age-and BMI-similar controls were assessed using the Behavior Rating Inventory of Executive Function (BRIEF), Neuropsychological Test Battery...
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