16 research outputs found
Chronic disease risk typologies among young adults in community college
Objectives: To address chronic disease risk holistically from a behavioral perspective, insights are needed to refine understanding of the covariance of key health behaviors. This study aims to identify distinct typologies of young adults based on 4 modifiable risk factors of chronic disease using a latent class analysis approach, and to describe patterns of class membership based on demographic characteristics, living arrangements, and weight. Methods: Overall, 441 young adults aged 18-35 attending community colleges in the Minnesota Twin Cities area completed a baseline questionnaire for the Choosing Healthy Options in College Environments and Settings study, a RCT. Behavioral items were used to create indicators for latent classes, and individuals were classified using maximum-probability assignment. Results: Three latent classes were identified: ‘active, binge-drinkers with a healthy dietary intake’ (13.1%); ‘non-active, moderate-smokers and non-drinkers with poor dietary intake’ (38.2%); ‘moderately active, non-smokers and non-drinkers with moderately healthy dietary intake’ (48.7%). Classes exhibited unique demographic and weight-related profiles. Conclusions: This study may contribute to the literature on health behaviors among young adults and provides evidence that there are weight and age differences among subgroups. Understanding how behaviors cluster is important for identifying groups for targeted interventions in community colleges
Assessment of the Noise Reduction Potential of Advanced Subsonic Transport Concepts for NASA's Environmentally Responsible Aviation Project
Aircraft system noise is predicted for a portfolio of NASA advanced concepts with 2025 entry-into-service technology assumptions. The subsonic transport concepts include tube-and-wing configurations with engines mounted under the wing, over the wing nacelle integration, and a double deck fuselage with engines at a mid-fuselage location. Also included are hybrid wing body aircraft with engines upstream of the fuselage trailing edge. Both advanced direct drive engines and geared turbofan engines are modeled. Recent acoustic experimental information was utilized in the prediction for several key technologies. The 301-passenger class hybrid wing body with geared ultra high bypass engines is assessed at 40.3 EPNLdB cumulative below the Stage 4 certification level. Other hybrid wing body and unconventional tube-and-wing configurations reach levels of 33 EPNLdB or more below the certification level. Many factors contribute to the system level result; however, the hybrid wing body in the 301-passenger class, as compared to a tubeand- wing with conventional engine under wing installation, has 11.9 EPNLdB of noise reduction due to replacing reflection with acoustic shielding of engine noise sources. Therefore, the propulsion airframe aeroacoustic interaction effects clearly differentiate the unconventional configurations that approach levels close to or exceed the 42 EPNLdB goal
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Optimization of disk generator performance for base-load power plant systems applications
Disk generators for use in base-load MHD power plants are examined for both open-cycle and closed-cycle operating modes. The OCD cases are compared with PSPEC results for a linear channel; enthalpy extractions up to 23% with 71% isentropic efficiency are achievable with generator inlet conditions similar to those used in PSPEC, thus confirming that the disk configuration is a viable alternative for base-load power generation. The evaluation of closed-cycle disks includes use of a simplified cycle model. High system efficiencies over a wide range of power levels are obtained for effective Hall coefficients in the range 2.3 to 4.9. Cases with higher turbulence (implying ..beta../sub eff/ less than or equal to 2.4) yield high system efficiencies at power levels of 100 to 500 MW/sub e/. All these CCD cases compare favorably with linear channels reported in the GE ECAS study, yielding higher isentropic efficiences for a given enthalpy extraction. Power densities in the range 70 to 170 MW/m/sup 3/ appear feasible, leading to very compact generator configurations
Numerical study of the 3-D flowfield for a supersonic jet exiting into a hypersonic stream from a conical surface
The Na+-K+-2Cl- cotransporter and the osmotic stress response in a model salt transport epithelium.
Epithelia are physiologically exposed to osmotic stress resulting in alteration
of cell volume in several aspects of their functioning; therefore, the activation
of ‘emergency’ systems of rapid cell volume regulation is fundamental in
their physiology. In this review, the physiological response to osmotic stress,
particularly hypertonic stress, was described in a salt-transporting epithelium,
the intestine of the euryhaline teleost European eel. This epithelium is
physiologically exposed to changes in extracellular osmolarity and represents
a good physiological model for functional studies on cellular volume regulation,
permitting the study of volume regulated ion transport mechanisms in
a native tissue. An absorptive form of the cotransporter, homologue of the
renal NKCC2, localized on the apical membrane, was found in the intestine
of the euryhaline teleost European eel. This cotransporter accounts for the
luminal uptake of Cl); it operates in series with a basolateral Cl) conductance
and presumably a basolateral electroneutral KCl cotransport and in
parallel with a luminal K+ conductance. The ion transport model described
for eel intestine, based on the operation of an absorptive luminal Na+–K+–
2Cl), is basically the same as the model that has been proposed for the thick
ascending limb (cTAL) of the mammalian renal cortex. This paper focuses on
the role of Na+–K+–2Cl) cotransport in the responses to hypertonic stress in
the eel intestine and the role of cytoskeleton (either actin-based or tubulin
based) is discussed