605 research outputs found

    Signal-to-noise ratio analysis and evaluation of the Hadamard imaging technique

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    The signal-to-noise ratio performance of the Hadamard imaging technique is analyzed and an experimental evaluation of a laboratory Hadamard imager is presented. A comparison between the performances of Hadamard and conventional imaging techniques shows that the Hadamard technique is superior only when the imaging objective lens is required to have an effective F (focus) number of about 2 or slower

    Analysis of testbed airborne multispectral scanner data from Superflux II

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    A test bed aircraft multispectral scanner (TBAMS) was flown during the James Shelf, Plume Scan, and Chesapeake Bay missions as part of the Superflux 2 experiment. Excellent correlations were obtained between water sample measurements of chlorophyll and sediment and TBAMS radiance data. The three-band algorithms used were insensitive to aircraft altitude and varying atmospheric conditions. This was particularly fortunate due to the hazy conditions during most of the experiments. A contour map of sediment, and also chlorophyll, was derived for the Chesapeake Bay plume along the southern Virginia-Carolina coastline. A sediment maximum occurs about 5 nautical miles off the Virginia Beach coast with a chlorophyll maximum slightly shoreward of this. During the James Shelf mission, a thermal anomaly (or front) was encountered about 50 miles from the coast. There was a minor variation in chlorophyll and sediment across the boundary. During the Chesapeake Bay mission, the Sun elevation increased from 50 degrees to over 70 degrees, interfering with the generation of data products

    An analysis of the facsimile-camera response to radiant point sources

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    In addition to imaging the surrounding terrain, planetary lander cameras may also be used to survey the stars to aid in locating the lander site. The response of the facsimile camera, which was selected for the Viking lander missions to Mars, to a radiant point source is formulated and shown to result in a statistical rather than deterministic signal. The signal statistics are derived and magnitudes are evaluated for the brighter visual and red stars. The probability of detecting the resultant statistical signals in photosensor and preamplifier noise and the associated probability of false alarms are also determined

    Carers Create: carer perspectives of a creative programme for people with dementia and their carers on the relationship within the (carer and cared for) dyad

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    Introduction Relationships between people with dementia and their carers can prove challenging over the trajectory of the disease. Interventions with a potential to address this include arts and music-based activities. This research project aimed to evaluate a community engagement programme (Carers Create) where both people with dementia and their carers participate together in singing and other activities. A specific focus was on the impact of the sessions on the dyadic relationship. Methods A grounded theory approach involved conducting three focus group interviews with carers of people with dementia (n=16) facilitated by members of a local U3A (University of the Third Age) who were trained and supported by university researchers. Recorded conversations were transcribed and analysed using a three-stage coding and thematic development technique. Results Four overarching themes were identified from the discourse: remembering the positive qualities of the cared-for; the physical and emotional demands of caring; Carers Create as a shared, beneficial activity; the enduring value of Carers Create. Conclusion Carers found the sessions to positively influence the relationship with the person they cared for through offering some relief from the day-to-day pressures of caring and in some cases restoring elements of a previously strong relationship. Crucial to the experience was the fact that the sessions included both carer and cared-for, offering activities to do together, and that they took place within a group, thereby offering a degree of mutual support. In addition, some carers were able to build on learning which had taken place and use certain techniques, such as singing, to help manage care, thus extending the improved relationship.

    Myoporum montanum R. Br.

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    https://thekeep.eiu.edu/herbarium_specimens_byname/21548/thumbnail.jp

    Evaluating changes in mental workload in indoor and outdoor ultra-distance cycling

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    Whilst increasing mental workload has been shown to have a detrimental effect on cycling performance and more generally to increase the risk of harm, no studies have measured how mental workload changes as a function of ultra-distance cycling, indoors or outdoors. Our objective was to measure the difference in mental workload, as indicated by changes in EEG theta power, components of HRV and psychomotor vigilance and as reported using the ‘NASA Task Load Index questionnaire’, before and after a 5 h indoor ride and outdoor ride completed at 65% of functional threshold power. Results of the NASA-TLX indicated the mental demand of outdoor cycling to be significantly less than that of indoor cycling. There were significant differences in the PVT results between the pre and the post outdoor ride average and median response times. The slowest 10% PVT responses were significantly slower pre than post the indoor ride. There were significant differences in HRV between pre and post outdoor and indoor rides, specifically, in the average RR intervals, RMSSD (ms2), LFPower (ms2), NN50. There were modest changes in indicators of mental workload during an ultra-distance cycle ride. As such, mental workload during ultra-distance cycling is unlikely to be a contributory factor to decreases in performance or to an increased likelihood of accident and injury

    Contributions of wood smoke and vehicle emissions to ambient concentrations of volatile organic compounds and particulate matter during the Yakima wintertime nitrate study

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    A multiple linear regression (MLR) chemical mass balance model was applied to data collected during an air quality field experiment in Yakima, WA, during January 2013 to determine the relative contribution of residential wood combustion (RWC) and vehicle emissions to ambient pollutant levels. Acetonitrile was used as a chemical tracer for wood burning and nitrogen oxides (NOx) as a chemical tracer for mobile sources. RWC was found to be a substantial source of gas phase air toxics in wintertime. The MLR model found RWC primarily responsible for emissions of formaldehyde (73%), acetaldehyde (69%), and black carbon (55%) and mobile sources primarily responsible for emissions of carbon monoxide (CO; 83%), toluene (81%), C2-alkylbenzenes (81%), and benzene (64%). When compared with the Environmental Protection Agency’s 2011 winter emission inventory, the MLR results suggest that the contribution of RWC to CO emissions was underestimated in the inventory by a factor of 2. Emission ratios to NOx from the MLR model agreed to within 25% with wintertime emission ratios predicted from the Motor Vehicle Emissions Simulator (MOVES) 2010b emission model for Yakima County for all pollutants modeled except for CO, C2-alkylbenzenes, and black carbon. The MLR model results suggest that MOVES was overpredicting mobile source emissions of CO relative to NOx by a factor of 1.33 and black carbon relative to NOx by about a factor of 3
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