997 research outputs found
Distance to food stores & adolescent male fruit and vegetable consumption: mediation effects
<p>Abstract</p> <p>Background</p> <p>The physical environments in which adolescents reside and their access to food stores may influence their consumption of fruit and vegetables. This association could either be direct or mediated via psychosocial variables or home availability of fruit and vegetables. A greater understanding of these associations would aide the design of new interventions. The purpose of this study was to examine associations between distance to food stores and restaurants and fruit and vegetable consumption and the possible mediating role of psychosocial variables and home availability.</p> <p>Methods</p> <p>Fruit and vegetable consumption of 204 Boy Scouts was assessed by a food frequency questionnaire in 2003. Participant addresses were geo-coded and distance to different types of food stores and restaurants calculated. Fruit and vegetable preferences, home availability and self-efficacy were measured. Regression models were run with backward deletion of non-significant environmental and psychosocial variables. Mediation tests were performed.</p> <p>Results</p> <p>Residing further away from a small food store (SFS) (convenience store and drug store) was associated with increased fruit and juice and low fat vegetable consumption. Residing closer to a fast food restaurant was associated with increased high fat vegetable and fruit and juice consumption. Vegetable preferences partially mediated (26%) the relationship between low fat vegetable consumption and distance to the nearest SFS.</p> <p>Conclusion</p> <p>Distance to SFS and fast food restaurants were associated with fruit and vegetable consumption among male adolescents. Vegetable preferences partially mediated the distance to low fat vegetable relationship. More research is needed to elucidate how environmental variables impact children's dietary intake.</p
Achieving fruit, juice, and vegetable recipe preparation goals influences consumption by 4th grade students
<p>Abstract</p> <p>Background</p> <p>Including children in food preparation activities has long been recommended as a method to encourage children's consumption, but has not been evaluated. Goal setting is also a common component of behavior change programs. This study assessed the impact of attaining goals to prepare fruit-juice or vegetable recipes on student fruit and vegetable consumption as part of a 10-week fruit and vegetable intervention for fourth grade students.</p> <p>Methods</p> <p>At six of the 10 sessions, students (n = 671) selected a fruit-juice or vegetable recipe to prepare at home before the next session. Students returned parent-signed notes reporting their child's goal attainment. Baseline and post consumption were assessed with up to four days of dietary recalls. Analyses included regression models predicting post consumption from the number of fruit-juice or vegetable recipe preparation goals attained, controlling for baseline consumption.</p> <p>Results</p> <p>In general, girls and Hispanic students achieved the most recipe preparation goals. For students with highest baseline fruit-juice consumption, post fruit-juice consumption was higher by about 1.0 serving for those achieving 2 or 3 fruit-juice recipe preparation goals. Post vegetable consumption was highest for students reporting the highest baseline vegetable consumption and who achieved two or three vegetable recipe preparation goals. In general, recipe goal setting was a useful procedure primarily for those with high baseline consumption.</p> <p>Conclusion</p> <p>This is one of the first reports demonstrating that home recipe preparation was correlated with dietary change among children.</p
A study of leeside flow field heat transfer on Shuttle Orbiter configuration
A coupled inviscid and viscous theoretical solution of the flow about the entire configuration is the desirable and comprehensive approach to defining thermal environments about the space shuttle orbiter. Simplified methods for predicting entry heating on leeside surfaces of the orbiter are considered. Wind tunnel heat transfer and oil flow data at Mach 6 and 10 and Reynolds numbers ranging from 500,000 to 73 million were used to develop correlations for the wing upper surface and the top surface of the fuselage. These correlations were extrapolated to flight Reynolds number and compared with heating data obtained during the shuttle STS-2 reentry. Efforts directed toward the wing leeside surface resulted in an approach which generally agreed with the flight data. Heating predictions for the upper fuselage were less successful due to the extreme complexity of local flow interactions and the associated heating environment
Effects of goal setting on dietary and physical activity changes in the Boy Scout badge projects.
Background: This study evaluates the relationship of goal setting to low-fat vegetable (LV) and fruit/100% juice (FJ) consumption and physical activity (PA) change. Methods: A total of 473 10- to 14-year-old Boy Scouts from Houston took part in a 9-week intervention. A two-group (LV and FJ or PA) intervention design was used with each group serving as the control for the other. Internet-based activities included goal setting at home. Food frequencies measured dietary intake. Results: Goals attained were not related to LV intake or PA. Immediate posttest FJ consumption increased about 0.7 servings as home FJ availability increased, but social desirability of response appeared to confound reports of FJ intake at posttest 6 months assessment. Conclusions: Goals attained were not related to LV intake or PA but was related to FJ intake, but only when home FJ availability was high and the relationship was confounded by social desirability of response. Further research is needed with higher quality measures of dietary intake to clarify these relationships
Bilayer graphene inclusions in rotational-stacked multilayer epitaxial graphene
Additional component in multi-layer epitaxial graphene grown on the
C-terminated surface of SiC, which exhibits the characteristic electronic
properties of a AB-stacked graphene bilayer, is identified in magneto-optical
response of this material. We show that these inclusions represent a
well-defined platform for accurate magneto-spectroscopy of unperturbed graphene
bilayers.Comment: 5 pages, 2 figures, to appear in Phys. Rev.
Quasi-classical cyclotron resonance of Dirac fermions in highly doped graphene
Cyclotron resonance in highly doped graphene has been explored using infrared
magnetotransmission. Contrary to previous work, which only focused on the
magneto-optical properties of graphene in the quantum regime, here we study the
quasi-classical response of this system. We show that it has a character of
classical cyclotron resonance, with an energy which is linear in the applied
magnetic field and with an effective cyclotron mass defined by the position of
the Fermi level m = E_F/v_F^2.Comment: 6 pages, 4 figure
A new beamline for laser spin-polarization at ISOLDE
A beamline dedicated to the production of laser-polarized radioactive beams
has been constructed at ISOLDE, CERN. We present here different simulations
leading to the design and construction of the setup, as well as technical
details of the full setup and examples of the achieved polarizations for
several radioisotopes. Beamline simulations show a good transmission through
the entire line, in agreement with observations. Simulations of the induced
nuclear spin-polarization as a function of atom-laser interaction length are
presented for Na, [1] and for Ar, which is studied in this
work. Adiabatic spin rotation of the spin-polarized ensemble of atoms, and how
this influences the observed nuclear ensemble polarization, are also performed
for the same nuclei. For Ar, we show that multiple-frequency pumping
enhances the ensemble polarization by a factor 1.85, in agreement with
predictions from a rate equations model.
[1] J. Phys. G: Nucl. Part. Phys./174408400
Electronic and Vibrational Properties of gamma-AlH3
Aluminum hydride (alane) AlH_3 is an important material in hydrogen storage
applications. It is known that AlH_3 exists in multiply forms of polymorphs,
where -AlH_3 is found to be the most stable with a hexagonal structure.
Recent experimental studies on -AlH_3 reported an orthorhombic
structure with a unique double-bridge bond between certain Al and H atoms. This
was not found in -AlH_3 or other polymorphs. Using density functional
theory, we have investigated the energetics, and the structural, electronic,
and phonon vibrational properties for the newly reported -AlH_3
structure. The current calculation concludes that -AlH_3 is less stable
than -AlH_3 by 2.1 KJ/mol. Interesting binding features associated with
the unique geometry of -AlH3 are discussed from the calculated
electronic properties and phonon vibrational modes. The binding of H-s with
higher energy Al-p,d orbitals is enhanced within the double-bridge arrangement,
giving rise to a higher electronic energy for the system. Distinguishable new
features in the vibrational spectrum of -AlH_3 were attributed to the
double-bridge and hexagonal-ring structures.Comment: 18 pages, 9 figures, submited to PR
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