539 research outputs found
Challenges of developing an electro-optical system for measuring man's operational envelope
In designing work stations and restraint systems, and in planning tasks to be performed in space, a knowledge of the capabilities of the operator is essential. Answers to such questions as whether a specific control or work surface can be reached from a given restraint and how much force can be applied are of particular interest. A computer-aided design system has been developed for designing and evaluating work stations, etc., and the Anthropometric Measurement Laboratory (AML) has been charged with obtaining the data to be used in design and modeling. Traditional methods of measuring reach and force are very labor intensive and require bulky equipment. The AML has developed a series of electro-optical devices for collecting reach data easily, in computer readable form, with portable systems. The systems developed, their use, and data collected with them are described
Development of an empirically based dynamic biomechanical strength model
The focus here is on the development of a dynamic strength model for humans. Our model is based on empirical data. The shoulder, elbow, and wrist joints are characterized in terms of maximum isolated torque, position, and velocity in all rotational planes. This information is reduced by a least squares regression technique into a table of single variable second degree polynomial equations determining the torque as a function of position and velocity. The isolated joint torque equations are then used to compute forces resulting from a composite motion, which in this case is a ratchet wrench push and pull operation. What is presented here is a comparison of the computed or predicted results of the model with the actual measured values for the composite motion
Nitrosylation of Myoglobin and Nitrosation of Cysteine by Nitrite in a Model System Simulating Meat Curing
Demand is growing for meat products cured without the addition of sodium nitrite. Instead of the direct addition of nitrite to meat in formulation, nitrite is supplied by bacterial reduction of natural nitrate often added as vegetable juice/powder. However, the rate of nitrite formation in this process is relatively slow, and the total ingoing nitrite is typically less than in conventional curing processes. The objective of this study was to determine the impact of the rate of addition of nitrite and the amount of nitrite added on nitrosylation/nitrosation reactions in a model meat curing system. Myoglobin was preferentially nitrosylated as no decrease in sulfhydryl groups was found until maximum nitrosylmyoglobin color was achieved. The cysteine–myoglobin model retained more sulfhydryl groups than the cysteine-only model (p \u3c 0.05). The rate of nitrite addition did not alter nitrosylation/nitrosation reactions (p \u3e 0.05). These data suggest that the amount of nitrite but not the rate of addition impacts the nitrosylation/nitrosation reactions this syste
Characterizing the lifetime phases of wildland fires from the Sioux Lookout District in Ontario.
Slow and Steady: Readiness, Pretreatment Weekly Strengthening Activity, and Pediatric Weight Management Program Completion
Background: Pediatric weight management programs have substantial attrition rates, which have led to recommendations to assess readiness prior to enrollment. Both pretreatment readiness scales and behaviors, such as exercise, have been theorized to predict subsequent program completion. The purpose of this study was to explore the role of self-reported pretreatment exercise in adolescents on completion of a pediatric weight management program and to explore the predictive ability of standard readiness scales. Methods: A total of 146 obese (BMI≥95th percentile) pediatric (ages 11?18) participants joined a 6-month multidisciplinary weight management program between March, 2007, and July, 2010. Completers were compared retrospectively to noncompleters on demographic, readiness, and pretreatment exercise practices from clinic-developed intake questionnaires using univariate analyses. Regression analyses specified the degree to which these variables predicted program completion. Results: The 6-month completion rate was 53%. There was no relationship between self-reported readiness and program completion. Self-reported pretreatment weekly strengthening activity (SA) was significantly associated with program completion, compared to those who performed SA either never [univariate odds ratio (OR) 3.18, 95% confidence interval (CI) 1.51?6.68, p=0.002; multivariate OR 2.43, 95% CI 1.06?5.58, p=0.036] or daily (univariate OR 4.90, 95% CI 1.74?13.77, p=0.002; multivariate OR 4.69, 95% CI 1.45?15.14, p=0.010). No relationship was found between other forms of exercise and program completion. Conclusions: Self-reported pretreatment weekly SA, but not standard readiness scales, predicted pediatric weight management program completion.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140330/1/chi.2013.0006.pd
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