342,540 research outputs found
Analytical Investigation of Innovation Dynamics Considering Stochasticity in the Evaluation of Fitness
We investigate a selection-mutation model for the dynamics of technological
innovation,a special case of reaction-diffusion equations. Although mutations
are assumed to increase the variety of technologies, not their average success
("fitness"), they are an essential prerequisite for innovation. Together with a
selection of above-average technologies due to imitation behavior, they are the
"driving force" for the continuous increase in fitness. We will give analytical
solutions for the probability distribution of technologies for special cases
and in the limit of large times.
The selection dynamics is modelled by a "proportional imitation" of better
technologies. However, the assessment of a technology's fitness may be
imperfect and, therefore, vary stochastically. We will derive conditions, under
which wrong assessment of fitness can accelerate the innovation dynamics, as it
has been found in some surprising numerical investigations.Comment: For related work see http://www.helbing.or
The relationship between physical activity, motor competence and health-related fitness in 14-year-old adolescents
Physical activity, physical fitness, and motor competence are important health-related constructs. However, the relationship between them, particularly among children and adolescents, is still unclear. In this study, motor competence (measured by the McCarron Assessment of Neuromuscular Development), pedometer-determined physical activity and physical fitness (aerobic fitness, muscle strength, muscle endurance, flexibility and body composition) were examined in a cohort of 1585 adolescents (771 girls, 814 boys) of mean age 14.1 yrs. Significant gender differences were observed for all measures except motor competence. Apart from hip and shoulder flexibility, males outperformed females. For both males and females, motor competence was associated with all fitness measures, physical activity was associated only with aerobic fitness and aerobic fitness was associated with physical activity, motor competence, BMI and chest pass. Among males, aerobic fitness was also associated with all other fitness tests. The correlations were, in general, moderate to weak. The results challenge the current focus on physical activity rather than physical fitness as the preferred intervention
Georgia's Youth: Overweight and Under-Active
A statewide assessment of the physical fitness and physical activity levels of Georgia's 5th and 7th graders
Facts about Iowa Law Enforcement Physical Standards for Pre-employment Testing, 2011
The Iowa Law Enforcement Academy Council, in recognizing the importance of physical fitness status for job performance, established this physical test regimen as a employment standard effective February 15, 1993. No person can be selected or appointed as a law enforcement officer without first successfully passing all of the elements of this test. (See 501 IAC 2.1, adopted pursuant to Section 80B.11(5), Code of Iowa.)
Upon entry into the Academy every candidate will be given the same test as an assessment for training purposes and to ensure that each recruit can undergo the physical demands of the Academy without undue risk of injury, and with a level of fatigue tolerance to meet all Academy requirements. If at the time of entrance into the Academy an officer does not meet minimum standards, he or she will not be admitted. This pamphlet will provide information on the rationale, purpose, testing procedures, standards of performance
and fitness activities to prepare for the fitness testing. It is intended to answer the basic questions pertaining to all aspects of the fitness testing process
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Influence of surgery and rehabilitation conditioning on psychophysiological fitness
The purpose of this study was to assess changes in psychophysiological fitness following reconstructive knee surgery and early phase (2.5 months) physical rehabilitation. Nine patients (7 male, 2 female; mean age, 29.9 years) electing to undergo anterior cruciate ligament reconstructive surgery (central third, bone-patella tendon-bone graft) were assessed on four separate assessment occasions post-surgery. Repeated measures ANOVAs showed significant condition (injured/non-injured leg) by test occasion (2 weeks pre-surgery and 6, 8 and 10 weeks post-surgery) interactions for knee ligamentous compliance (anterior tibiofemoral displacement), peak force and electromechanical delay associated with the knee flexors of the injured and noninjured legs (F3,24 = 4.7 to 6.6; p < 0.01), together with individualized emotional profile disturbance scores that were significantly less at 10 weeks post-surgery compared to pre-surgery, 6 weeks and 8 weeks post-surgery (F3,24 = 7.6; p < 0.01). Spearman rank correlation coefficients identified significant relationships between musculoskeletal fitness and emotional profile scores at pre-surgery (r = 0.69–0.72; p < 0.05) and at 8 weeks post-surgery (r = 0.70–0.73; p < 0.05). The 6 Bi-POMS subscales and the 12 ERAIQ responses found inconsistent patterns of response and relationships across the assessment occasions. Overall, the patterning of changes and associations amongst emotional performance profile discrepancy scores in conjunction with those scores from indices of musculoskeletal fitness performance capability offered important support for the efficacy of an approach which integrates self-perceptive and objective measurements of fitness capability during rehabilitation following surgery to a synovial joint
No-reference image quality assessment through the von Mises distribution
An innovative way of calculating the von Mises distribution (VMD) of image
entropy is introduced in this paper. The VMD's concentration parameter and some
fitness parameter that will be later defined, have been analyzed in the
experimental part for determining their suitability as a image quality
assessment measure in some particular distortions such as Gaussian blur or
additive Gaussian noise. To achieve such measure, the local R\'{e}nyi entropy
is calculated in four equally spaced orientations and used to determine the
parameters of the von Mises distribution of the image entropy. Considering
contextual images, experimental results after applying this model show that the
best-in-focus noise-free images are associated with the highest values for the
von Mises distribution concentration parameter and the highest approximation of
image data to the von Mises distribution model. Our defined von Misses fitness
parameter experimentally appears also as a suitable no-reference image quality
assessment indicator for no-contextual images.Comment: 29 pages, 11 figure
Measuring fitness of Kenyan children with polyparasitic infections using the 20-meter shuttle run test as a morbidity metric.
BACKGROUND: To date, there has been no standardized approach to the assessment of aerobic fitness among children who harbor parasites. In quantifying the disability associated with individual or multiple chronic infections, accurate measures of physical fitness are important metrics. This is because exercise intolerance, as seen with anemia and many other chronic disorders, reflects the body's inability to maintain adequate oxygen supply (VO(2) max) to the motor tissues, which is frequently linked to reduced quality-of-life in terms of physical and job performance. The objective of our study was to examine the associations between polyparasitism, anemia, and reduced fitness in a high risk Kenyan population using novel implementation of the 20-meter shuttle run test (20mSRT), a well-standardized, low-technology physical fitness test.
METHODOLOGY/PRINCIPAL FINDINGS: Four villages in coastal Kenya were surveyed during 2009-2010. Children 5-18 years were tested for infection with Schistosoma haematobium (Sh), malaria, filaria, and geohelminth infections by standard methods. After anthropometric and hemoglobin testing, fitness was assessed with the 20 mSRT. The 20 mSRT proved easy to perform, requiring only minimal staff training. Parasitology revealed high prevalence of single and multiple parasitic infections in all villages, with Sh being the most common (25-62%). Anemia prevalence was 45-58%. Using multiply-adjusted linear modeling that accounted for household clustering, decreased aerobic capacity was significantly associated with anemia, stunting, and wasting, with some gender differences.
CONCLUSIONS/SIGNIFICANCE: The 20 mSRT, which has excellent correlation with VO(2), is a highly feasible fitness test for low-resource settings. Our results indicate impaired fitness is common in areas endemic for parasites, where, at least in part, low fitness scores are likely to result from anemia and stunting associated with chronic infection. The 20 mSRT should be used as a common metric to quantify physical fitness and compare sub-clinical disability across many different disorders and community settings
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