The University of Arizona Campus Repository
http://repository.arizona.edu:80
The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Mon, 17 Jun 2019 11:47:54 GMT2019-06-17T11:47:54ZFeasibility and acceptability of a beverage intervention for Hispanic adults: results from a pilot randomized controlled trial
http://hdl.handle.net/10150/632903
Feasibility and acceptability of a beverage intervention for Hispanic adults: results from a pilot randomized controlled trial
Garcia, David O; Morrill, Kristin E; Aceves, Benjamin; Valdez, Luis A; Rabe, Brooke A; Bell, Melanie L; Hakim, Iman A; Martinez, Jessica A; Thomson, Cynthia A
Objective To assess the feasibility and acceptability of a beverage intervention in Hispanic adults. Design Eligible individuals identified as Hispanic, were 18-64 years old and had BMI 30.0-50.0 kg/m(2). Participants were randomized 2:2:1 to one of three beverages: Mediterranean lemonade (ML), green tea (GT) or flavoured water control (FW). After a 2-week washout period, participants were asked to consume 32 oz (946 ml) of study beverage daily for 6 weeks and avoid other sources of tea, citrus, juice and sweetened beverages; water was permissible. Fasting blood samples were collected at baseline and 8 weeks to assess primary and secondary efficacy outcomes. Setting Tucson, AZ, USA. Participants Fifty-two participants were recruited over 6 months; fifty were randomized (twenty-one ML, nineteen GT, ten FW). Study population mean (sd) age 44.6 (sd 10.2) years, BMI 35.9 (4.6) kg/m(2); 78 % female. Results Forty-four (88 %) completed the 8-week assessment. Self-reported adherence was high. No significant change (95 % CI) in total cholesterol (mg/dl) from baseline was shown -1.7 (-14.2, 10.9), -3.9 (-17.2, 9.4) and -13.2 (-30.2, 3.8) for ML, GT and FW, respectively. Mean change in HDL-cholesterol (mg/dl) -2.3 (-5.3, 0.7; ML), -1.0 (-4.2, 2.2; GT), -3.9 (-8.0, 0.2; FW) and LDL-cholesterol (mg/dl) 0.2 (-11.3, 11.8; ML), 0.5 (-11.4, 12.4; GT), -9.8 (-25.0, 5.4; FW) were also non-significant. Fasting glucose (mg/dl) increased significantly by 5.2 (2.6, 7.9; ML) and 3.3 (0.58, 6.4; GT). No significant change in HbA1c was demonstrated. Due to the small sample size, potential confounders and effect modifiers were not investigated. Conclusions Recruitment and retention figures indicate that a larger-scale trial is feasible; however, favourable changes in cardiometabolic biomarkers were not demonstrated.
Fri, 01 Mar 2019 00:00:00 GMThttp://hdl.handle.net/10150/6329032019-03-01T00:00:00ZMethods of optimizing and evaluating geometrical lightguides with microstructure mirrors for augmented reality displays
http://hdl.handle.net/10150/632902
Methods of optimizing and evaluating geometrical lightguides with microstructure mirrors for augmented reality displays
Xu, Miaomiao; Hua, Hong
Waveguide or lightguide technology has been widely used in the state-of-the-art, see-through, near-eye displays to reduce system weight and form factor. Although a few of the current products use a geometrical lightguide as an optical combiner, its design and performance assessment methods have been barely discussed. In this paper, by taking into account the factors affecting retinal image quality, we presented novel methods for quantifying and evaluating the optical performances and artifacts of geometrical lightguides based on microstructure mirror arrays, and proposed new merit functions and a novel process for systematic optimization of such lightguides. A lightguide design example implementing the evaluation and optimization methods are demonstrated, and the resulted lightguide is then further utilized as a combiner for the design of a lightweight, glasses-like, see-through, near-eye display. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Mon, 18 Feb 2019 00:00:00 GMThttp://hdl.handle.net/10150/6329022019-02-18T00:00:00ZNon-equilibrium dynamics in the dual-wavelength operation of vertical external-cavity surface-emitting lasers
http://hdl.handle.net/10150/632901
Non-equilibrium dynamics in the dual-wavelength operation of vertical external-cavity surface-emitting lasers
Kilen, I.; Hader, J.; Koch, S. W.; Moloney, J. V.
Microscopic many-body theory coupled with Maxwell's equation is used to study dual-wavelength operation in vertical external-cavity surface-emitting lasers. The intrinsically dynamic nature of coexisting emission wavelengths in semiconductor lasers is associated with characteristic non-equilibrium carrier dynamics, which causes significant deformations of the quasi-equilibrium gain and carrier inversion. Extended numerical simulations are employed to efficiently investigate the parameter space to identify the regime for dual-wavelength operation. Using a frequency selective intracavity etalon, two families of modes are stabilized with dynamical interchange of the strongest emission peaks. For this operation mode, anti-correlated intensity noise is observed in agreement with the experiment. A method using effective frequency selective filtering is suggested for stabilization of genuine dual-wavelength output. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Mon, 18 Feb 2019 00:00:00 GMThttp://hdl.handle.net/10150/6329012019-02-18T00:00:00ZApproximating geodesics via random points
http://hdl.handle.net/10150/632900
Approximating geodesics via random points
Davis, Erik; Sethuraman, Sunder
Given a cost functional F on paths gamma in a domain D subset of R-d, in the form 1 F(gamma) = integral(1)(0) f (gamma(t), gamma(t)) dt , it is of interest to approximate its minimum cost and geodesic paths. Let X-1,...X-n be points drawn independently from D according to a distribution with a density. Form a random geometric graph on the points where X-i and X-j are connected when 0 < vertical bar X-i - X-j vertical bar < epsilon, and the length scale epsilon = epsilon(n) vanishes at a suitable rate. For a general class of functionals F, associated to Finsler and other distances on D, using a probabilistic form of Gamma convergence, we show that the minimum costs and geodesic paths, with respect to types of approximating discrete cost functionals, built from the random geometric graph, converge almost surely in various senses to those corresponding to the continuum cost F, as the number of sample points diverges. In particular, the geodesic path convergence shown appears to be among the first results of its kind.
Sat, 01 Jun 2019 00:00:00 GMThttp://hdl.handle.net/10150/6329002019-06-01T00:00:00Z