1,847 research outputs found
Tunable lasers for water vapor measurements and other lidar applications
A tunable dye laser suitable for differential absorption (DIAL) measurements of water vapor in the troposphere was constructed. A multi-pass absorption cell for calibration was also constructed for use in atmospheric DIAL measurements of water vapor
Assessing the short-term outcomes of a community-based intervention for overweight and obese children: The MEND 5-7 programme
Objective The aim of this study was to report outcomes of the UK service level delivery of MEND (Mind,Exercise,Nutrition...Do it!) 5-7, a multicomponent, community-based, healthy lifestyle intervention designed for overweight and obese children aged 5–7 years and their families.
Design Repeated measures.
Setting Community venues at 37 locations across the UK.
Participants 440 overweight or obese children (42% boys; mean age 6.1 years; body mass index (BMI) z-score 2.86) and their parents/carers participated in the intervention.
Intervention MEND 5-7 is a 10-week, family-based, child weight-management intervention consisting of weekly group sessions. It includes positive parenting, active play, nutrition education and behaviour change strategies. The intervention is designed to be scalable and delivered by a range of health and social care professionals.
Primary and secondary outcome measures The primary outcome was BMI z-score. Secondary outcome measures included BMI, waist circumference, waist circumference z-score, children's psychological symptoms, parenting self-efficacy, physical activity and sedentary behaviours and the proportion of parents and children eating five or more portions of fruit and vegetables.
Results 274 (62%) children were measured preintervention and post-intervention (baseline; 10-weeks). Post-intervention, mean BMI and waist circumference decreased by 0.5 kg/m2 and 0.9 cm, while z-scores decreased by 0.20 and 0.20, respectively (p<0.0001). Improvements were found in children's psychological symptoms (−1.6 units, p<0.0001), parent self-efficacy (p<0.0001), physical activity (+2.9 h/week, p<0.01), sedentary activities (−4.1 h/week, p<0.0001) and the proportion of parents and children eating five or more portions of fruit and vegetables per day (both p<0.0001). Attendance at the 10 sessions was 73% with a 70% retention rate.
Conclusions Participation in the MEND 5-7 programme was associated with beneficial changes in physical, behavioural and psychological outcomes for children with complete sets of measurement data, when implemented in UK community settings under service level conditions. Further investigation is warranted to establish if these findings are replicable under controlled conditions
Light Scattering from Nonequilibrium Concentration Fluctuations in a Polymer solution
We have performed light-scattering measurements in dilute and semidilute
polymer solutions of polystyrene in toluene when subjected to stationary
temperature gradients. Five solutions with concentrations below and one
solution with a concentration above the overlap concentration were
investigated. The experiments confirm the presence of long-range nonequilibrium
concentration fluctuations which are proportional to , where
is the applied temperature gradient and is the wave number of
the fluctuations. In addition, we demonstrate that the strength of the
nonequilibrium concentration fluctuations, observed in the dilute and
semidilute solution regime, agrees with theoretical values calculated from
fluctuating hydrodynamics. Further theoretical and experimental work will be
needed to understand nonequilibrium fluctuations in polymer solutions at higher
concentrations.Comment: revtex, 16 pages, 7 figures. J. Chem. Phys., to appea
Spacelab experiment definition study on phase transition and critical phenomena in fluids: Interim report on experimental justification
Pure fluids and fluid mixtures near critical points are identified and are related to the progress of several disciplines. Consideration is given to thermodynamic properties, transport properties, and the complex nonlinear phenomena which occur when fluids undergo phase transitions in the critical region. The distinction is made between practical limits which may be extended by advances in technology and intrinsic ones which arise from the modification of fluid properties by the earth's gravitational field. The kinds of experiments near critical points which could best exploit the low gravity environment of an orbiting laboratory are identified. These include studies of the index of refraction, constant volume specific heat, and phase separation
Classifying Vegetative Cover with Landsat Digital Data, Great Dismal Swamp, Virginia and North Carolina
Geometrically corrected and temporally registered Landsat digital data from April and February 1974 have been used to classify and map vegetative cover in the Great Dismal Swamp in Virginia and North Carolina. Cover classes were grouped into dominance types and subclasses according to the new U.S. Fish and Wildlife Service wetland classification system. Four data sets were analyzed on the Interactive Digital Image Manipulation System (IDIMS): (1) April data (2) February data (3) bands 5 and 7 from April and February and (4) all 8 bands from April and February.
Eighteen dominance types were established for the swamp on the basis of season, dominant canopy species and, in some deciduous classes, on type of understory. The subclasses and dominance types vary in number and composition according to season of data acquisition. Percentage estimates for the swamp subclasses were as follows: shallow water/benthos 2.2 percent, broad-leaved evergreen forested wetland 6.5 percent, needle-leaved evergreen forested wetland 16 percent, broadleaved deciduous forested wetland 67.7 percent, narrow-leaved deciduous forested wetland 1 percent, broad-leaved evergreen shrub wetland 5 percent, and altered 1.6 percent.
IDIMS algorithms were used to choose 65 random, 10x10 pixel, sample plots and t o generate the geometric coordinates (line/column; latitude/longitude) for these samples. The plots were transferred to 1:65,000-scale color infrared photographs of the swamp and each sample plot was photointerpreted for dominance type, subclass, and acreage. The photointerpretation results are being compared with IDIMS classification for each data set to measure the accuracy of classification. In addition, we are using the same sample plots to assess the accuracy of previous classifications made with Landsat digital data from data from the same data sets and from different dates using IDIMS, Image 100, and Laboratory for Applications of Remote Sensing System (LARSYS)
Hole Spin Mixing in InAs Quantum Dot Molecules
Holes confined in single InAs quantum dots have recently emerged as a
promising system for the storage or manipulation of quantum information. These
holes are often assumed to have only heavy-hole character and further assumed
to have no mixing between orthogonal heavy hole spin projections (in the
absence of a transverse magnetic field). The same assumption has been applied
to InAs quantum dot molecules formed by two stacked InAs quantum dots that are
coupled by coherent tunneling of the hole between the two dots. We present
experimental evidence of the existence of a hole spin mixing term obtained with
magneto-photoluminescence spectroscopy on such InAs quantum dot molecules. We
use a Luttinger spinor model to explain the physical origin of this hole spin
mixing term: misalignment of the dots along the stacking direction breaks the
angular symmetry and allows mixing through the light-hole component of the
spinor. We discuss how this novel spin mixing mechanism may offer new spin
manipulation opportunities that are unique to holes.Comment: 13 pages, 9 figure
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