4,395 research outputs found

    A Pilot Study of a Pictorial Bilingual Nutrition Education Game to Improve the Consumption of Healthful Foods in a Head Start Population

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    The prevalence of early childhood obesity has increased dramatically particularly among the Mexican American population. Obesity leads to earlier onset of related diseases such as type 2 diabetes. The Head Start population of Texas is largely Mexican American. Dietary intake in this population demonstrated a diet very low in fiber, high in salt, and containing excessive calories with a low intake of fruit and vegetables. This study was performed in a Texas Head Start population to evaluate a bilingual pictorial nutrition education game. Acceptance of the bilingual concept and the game had been previously studied in a Head Start population in five Texas counties. The effectiveness in producing a change in eating habits was studied as a pilot project 413 children and their parents at the Bastrop County Head Start. Parents were asked to supply data about at home food frequency at the beginning and the end of the school year and the results compared. The parents were given a demonstration of the educational objectives and the students played the game throughout the year. By the end of the school year there was a statistically significant increase in the vegetables offered to this population both during the week at home (p = 0.009) and on the weekends (p = 0.02)

    Nonlinear Elasticity, Fluctuations and Heterogeneity of Nematic Elastomers

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    Liquid crystal elastomers realize a fascinating new form of soft matter that is a composite of a conventional crosslinked polymer gel (rubber) and a liquid crystal. These {\em solid} liquid crystal amalgams, quite similarly to their (conventional, fluid) liquid crystal counterparts, can spontaneously partially break translational and/or orientational symmetries, accompanied by novel soft Goldstone modes. As a consequence, these materials can exhibit unconventional elasticity characterized by symmetry-enforced vanishing of some elastic moduli. Thus, a proper description of such solids requires an essential modification of the classical elasticity theory. In this work, we develop a {\em rotationally invariant}, {\em nonlinear} theory of elasticity for the nematic phase of ideal liquid crystal elastomers. We show that it is characterized by soft modes, corresponding to a combination of long wavelength shear deformations of the solid network and rotations of the nematic director field. We study thermal fluctuations of these soft modes in the presence of network heterogeneities and show that they lead to a large variety of anomalous elastic properties, such as singular length-scale dependent shear elastic moduli, a divergent elastic constant for splay distortion of the nematic director, long-scale incompressibility, universal Poisson ratios and a nonlinear stress-strain relation fo arbitrary small strains. These long-scale elastic properties are {\em universal}, controlled by a nontrivial zero-temperature fixed point and constitute a qualitative breakdown of the classical elasticity theory in nematic elastomers. Thus, nematic elastomers realize a stable ``critical phase'', characterized by universal power-law correlations, akin to a critical point of a continuous phase transition, but extending over an entire phase.Comment: 61 pages, 24 eps pages, submitted to Annals of Physic

    A Method of Drusen Measurement Based on the Geometry of Fundus Reflectance

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    BACKGROUND: The hallmarks of age-related macular degeneration, the leading cause of blindness in the developed world, are the subretinal deposits known as drusen. Drusen identification and measurement play a key role in clinical studies of this disease. Current manual methods of drusen measurement are laborious and subjective. Our purpose was to expedite clinical research with an accurate, reliable digital method. METHODS: An interactive semi-automated procedure was developed to level the macular background reflectance for the purpose of morphometric analysis of drusen. 12 color fundus photographs of patients with age-related macular degeneration and drusen were analyzed. After digitizing the photographs, the underlying background pattern in the green channel was leveled by an algorithm based on the elliptically concentric geometry of the reflectance in the normal macula: the gray scale values of all structures within defined elliptical boundaries were raised sequentially until a uniform background was obtained. Segmentation of drusen and area measurements in the central and middle subfields (1000 μm and 3000 μm diameters) were performed by uniform thresholds. Two observers using this interactive semi-automated software measured each image digitally. The mean digital measurements were compared to independent stereo fundus gradings by two expert graders (stereo Grader 1 estimated the drusen percentage in each of the 24 regions as falling into one of four standard broad ranges; stereo Grader 2 estimated drusen percentages in 1% to 5% intervals). RESULTS: The mean digital area measurements had a median standard deviation of 1.9%. The mean digital area measurements agreed with stereo Grader 1 in 22/24 cases. The 95% limits of agreement between the mean digital area measurements and the more precise stereo gradings of Grader 2 were -6.4 % to +6.8 % in the central subfield and -6.0 % to +4.5 % in the middle subfield. The mean absolute differences between the digital and stereo gradings 2 were 2.8 +/- 3.4% in the central subfield and 2.2 +/- 2.7% in the middle subfield. CONCLUSIONS: Semi-automated, supervised drusen measurements may be done reproducibly and accurately with adaptations of commercial software. This technique for macular image analysis has potential for use in clinical research

    Quasi-static imaged-based immersed boundary-finite element model of human left ventricle in diastole

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    SUMMARY: Finite stress and strain analyses of the heart provide insight into the biomechanics of myocardial function and dysfunction. Herein, we describe progress toward dynamic patient-specific models of the left ventricle using an immersed boundary (IB) method with a finite element (FE) structural mechanics model. We use a structure-based hyperelastic strain-energy function to describe the passive mechanics of the ventricular myocardium, a realistic anatomical geometry reconstructed from clinical magnetic resonance images of a healthy human heart, and a rule-based fiber architecture. Numerical predictions of this IB/FE model are compared with results obtained by a commercial FE solver. We demonstrate that the IB/FE model yields results that are in good agreement with those of the conventional FE model under diastolic loading conditions, and the predictions of the LV model using either numerical method are shown to be consistent with previous computational and experimental data. These results are among the first to analyze the stress and strain predictions of IB models of ventricular mechanics, and they serve both to verify the IB/FE simulation framework and to validate the IB/FE model. Moreover, this work represents an important step toward using such models for fully dynamic fluid–structure interaction simulations of the heart

    Objectively measured physical activity and fat mass in a large cohort of children

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    Background Previous studies have been unable to characterise the association between physical activity and obesity, possibly because most relied on inaccurate measures of physical activity and obesity. Methods and Findings We carried out a cross sectional analysis on 5,500 12-year-old children enrolled in the Avon Longitudinal Study of Parents and Children. Total physical activity and minutes of moderate and vigorous physical activity (MVPA) were measured using the Actigraph accelerometer. Fat mass and obesity (defined as the top decile of fat mass) were measured using the Lunar Prodigy dual x-ray emission absorptiometry scanner. We found strong negative associations between MVPA and fat mass that were unaltered after adjustment for total physical activity. We found a strong negative dose-response association between MVPA and obesity. The odds ratio for obesity in adjusted models between top and the bottom quintiles of minutes of MVPA was 0.03 (95% confidence interval [CI] 0.01-0.13, p-value for trend < 0.0001) in boys and 0.36 (95% CI 0.17-0.74, p-value for trend = 0.006) in girls. Conclusions We demonstrated a strong graded inverse association between physical activity and obesity that was stronger in boys. Our data suggest that higher intensity physical activity may be more important than total activity

    The impact of the Netherlandish landscape tradition on poetry and painting in early modern England

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    Copyright © 2013 The University of Chicago Press.The relationship between poetry and painting has been one of the most debated issues in the history of criticism. The present article explores this problematic relationship in the context of sixteenth- and seventeenth-century England, taking into account theories of rhetoric, visual perception, and art. It analyzes a rare case in which a specific school of painting directly inspired poetry: in particular, the ways in which the Netherlandish landscape tradition influenced natural descriptions in the poem Poly-Olbion (1612, 1622) by Michael Drayton (1563–1631). Drayton — under the influence of the artistic principles of landscape depiction as explained in Henry Peacham’s art manuals, as well as of direct observation of Dutch and Flemish landscape prints and paintings — successfully managed to render pictorial landscapes into poetry. Through practical examples, this essay will thoroughly demonstrate that rhetoric is capable of emulating pictorial styles in a way that presupposes specialized art-historical knowledge, and that pictorialism can be the complex product as much of poetry and rhetoric as of painting and art-theoretical vocabulary

    When Fat Meets Disability in Poverty Porn: exploring the cultural mechanisms of suspicion in Too Fat to Work

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    There has been a distinct neglect of dis/ability in socio-cultural analysis of poverty porn (Runswick-Cole and Goodley 2015). This paper applies framing analysis to reality TV documentaries that feature larger bodied, disabled, welfare claimants to examine how cultural literacies of fatness and ‘obesity’ are drawn upon to cast suspicion upon disability welfare claimants in so-called poverty-porn. With a focus on Channel 5’s Benefit Britain series, Bene£its Too Fat to Work we demonstrate that enduring and harmful representations of 'obesity' are put to the work of securing public consent for a post-welfare society in the UK

    Stop smoking practitioner consensus on barriers and facilitators to smoking cessation in pregnancy and how to address these: A modified Delphi survey.

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    Introduction Pregnant women can experience barriers and facilitators towards achieving smoking cessation. We sought consensus from smoking cessation practitioners on how influential pre-identified barriers and facilitators can be on pregnant women's smoking behaviour, and how difficult these might be to manage. Suggestions for techniques that could help overcome the barriers or enhance the facilitators were elicited and consensus sought on the appropriateness for their use in practice. Methods Forty-four practitioners who provided cessation support to pregnant women completed a three-round modified Delphi survey. Round one sought consensus on the ‘influence’ and ‘difficulty’ of the barriers and facilitators, and gathered respondents' suggestions on ways to address these. Rounds two and three sought further consensus on the barriers and facilitators and on ‘appropriateness’ of the respondent-suggested techniques. The techniques were coded for behaviour change techniques (BCTs) content using existing taxonomies. Results Barriers and facilitators considered to be the most important mainly related to the influence of significant others and the women's motivation & self-efficacy. Having a supportive partner was considered the most influential, whereas lack of support from partner was the only barrier that reached consensus as being difficult to manage. Barriers relating to social norms were also considered influential, however these received poor coverage of respondent-suggested techniques. Those considered the easiest to address mainly related to aspects of cessation support, including misconceptions surrounding the use of nicotine replacement therapy (NRT). Barriers and facilitators relating to the women's motivation & self-efficacy, such as the want to protect the baby, were also considered as being particularly easy to address. Fifty of the 54 respondent-suggested techniques reached consensus as being appropriate. Those considered the most appropriate ranged from providing support early, giving correct information on NRT, highlighting risks and benefits and reinforcing motivating beliefs. Thirty-three BCTs were identified from the respondent-suggested techniques. ‘Social support (unspecified)’, ‘Tailor interactions appropriately’ and ‘Problem solving’ were the most frequently coded BCTs. Conclusions Involving partners in quit attempts was advocated. Existing support could be potentially improved by establishing appropriate ways to address barriers relating to pregnant smokers' ‘social norms’. In general, providing consistent and motivating support seemed favourable

    Anisotropic behaviour of human gallbladder walls

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    Inverse estimation of biomechanical parameters of soft tissues from non-invasive measurements has clinical significance in patient-specific modelling and disease diagnosis. In this paper, we propose a fully nonlinear approach to estimate the mechanical properties of the human gallbladder wall muscles from in vivo ultrasound images. The iteration method consists of a forward approach, in which the constitutive equation is based on a modified Hozapfel–Gasser–Ogden law initially developed for arteries. Five constitutive parameters describing the two orthogonal families of fibres and the matrix material are determined by comparing the computed displacements with medical images. The optimisation process is carried out using the MATLAB toolbox, a Python code, and the ABAQUS solver. The proposed method is validated with published artery data and subsequently applied to ten human gallbladder samples. Results show that the human gallbladder wall is anisotropic during the passive refilling phase, and that the peak stress is 1.6 times greater than that calculated using linear mechanics. This discrepancy arises because the wall thickness reduces by 1.6 times during the deformation, which is not predicted by conventional linear elasticity. If the change of wall thickness is accounted for, then the linear model can used to predict the gallbladder stress and its correlation with pain. This work provides further understanding of the nonlinear characteristics of human gallbladder
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