Microtubule assembly governed by tubulin allosteric gain in flexibility and lattice induced fit

PubMed Central

2018-01-01

Microtubules (MTs) are key components of the cytoskeleton and play a central role in cell division and development. MT assembly is known to be associated with a structural change in αβ-tubulin dimers from kinked to straight conformations. How GTP binding renders individual dimers polymerization-competent, however, is still unclear. Here, we have characterized the conformational dynamics and energetics of unassembled tubulin using atomistic molecular dynamics and free energy calculations. Contrary to existing allosteric and lattice models, we find that GTP-tubulin favors a broad range of almost isoenergetic curvatures, whereas GDP-tubulin has a much lower bending flexibility. Moreover, irrespective of the bound nucleotide and curvature, two conformational states exist differing in location of the anchor point connecting the monomers that affects tubulin bending, with one state being strongly favored in solution. Our findings suggest a new combined model in which MTs incorporate and stabilize flexible GTP-dimers with a specific anchor point state. PMID:29652248

The effects of senior brain health exercise program on basic physical fitness, cognitive function and BDNF of elderly women - a feasibility study.

PubMed

Byun, Jung-Eun; Kang, Eun-Bum

2016-06-01

This study was to investigate the impacts of senior brain heath exercise (SBHE) program for 12 weeks to basic active physical fitness, cognitive function and brain derived neurotrophic factor (BDNF) in elderly women. Subject of this study is total of 24 women in the age of 65-79 who can conduct normal daily activity and communication but have not participated in regular exercise in recent 6 months. The study groups were divided into an exercise group (EG, n=13) and a control group (CG, n=11). The exercise program was consisted of SBHE, and training frequency was 4 times weekly, of which training time was a total of 50 minutes each time in level of intensity of 9-14 by rating of perceived exertion (RPE). First, 12-week SBHE program has shown statistical increase in basic physical fitness in the EG comparing with the CG, such as lower body strength, upper body strength and aerobic endurance, but not in flexibility, agility and dynamic balance. Second, in the case of Mini-mental state examination Korean version (MMSE-K) and BDNF, it showed that there was a statistically significant increase in the EG comparing with the CG. In this study, 12-week SBHE program has resulted in positive effect on change of basic physical fitness (strength and aerobic endurance), cognitive function and BDNF. If above program adds movements that can enhance flexibility, dynamic balance and agility, this can be practical exercise program to help seniors maintain overall healthy lifestyle.

WScore: A Flexible and Accurate Treatment of Explicit Water Molecules in Ligand-Receptor Docking.

PubMed

Murphy, Robert B; Repasky, Matthew P; Greenwood, Jeremy R; Tubert-Brohman, Ivan; Jerome, Steven; Annabhimoju, Ramakrishna; Boyles, Nicholas A; Schmitz, Christopher D; Abel, Robert; Farid, Ramy; Friesner, Richard A

2016-05-12

We have developed a new methodology for protein-ligand docking and scoring, WScore, incorporating a flexible description of explicit water molecules. The locations and thermodynamics of the waters are derived from a WaterMap molecular dynamics simulation. The water structure is employed to provide an atomic level description of ligand and protein desolvation. WScore also contains a detailed model for localized ligand and protein strain energy and integrates an MM-GBSA scoring component with these terms to assess delocalized strain of the complex. Ensemble docking is used to take into account induced fit effects on the receptor conformation, and protein reorganization free energies are assigned via fitting to experimental data. The performance of the method is evaluated for pose prediction, rank ordering of self-docked complexes, and enrichment in virtual screening, using a large data set of PDB complexes and compared with the Glide SP and Glide XP models; significant improvements are obtained.

Dynamic prediction in functional concurrent regression with an application to child growth.

PubMed

Leroux, Andrew; Xiao, Luo; Crainiceanu, Ciprian; Checkley, William

2018-04-15

In many studies, it is of interest to predict the future trajectory of subjects based on their historical data, referred to as dynamic prediction. Mixed effects models have traditionally been used for dynamic prediction. However, the commonly used random intercept and slope model is often not sufficiently flexible for modeling subject-specific trajectories. In addition, there may be useful exposures/predictors of interest that are measured concurrently with the outcome, complicating dynamic prediction. To address these problems, we propose a dynamic functional concurrent regression model to handle the case where both the functional response and the functional predictors are irregularly measured. Currently, such a model cannot be fit by existing software. We apply the model to dynamically predict children's length conditional on prior length, weight, and baseline covariates. Inference on model parameters and subject-specific trajectories is conducted using the mixed effects representation of the proposed model. An extensive simulation study shows that the dynamic functional regression model provides more accurate estimation and inference than existing methods. Methods are supported by fast, flexible, open source software that uses heavily tested smoothing techniques. © 2017 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

Current Issues in Flexibility Fitness.

ERIC Educational Resources Information Center

Knudson, Duane V.; Magnusson, Peter; McHugh, Malachy

2000-01-01

Physical activity is extremely important in maintaining good health. Activity is not possible without a certain amount of flexibility. This report discusses issues related to flexibility fitness. Flexibility is a property of the musculoskeletal system that determines the range of motion achievable without injury to the joints. Static flexibility…

Influence of weight status on physical and mental health in Moroccan perimenopausal women

PubMed Central

Oudghiri, Dia Eddine; Ruiz-Cabello, Pilar; Camiletti-Moirón, Daniel; Fernández, María Del Mar; Aranda, Pilar; Aparicio, Virginia Ariadna

2016-01-01

Introduction There is a lack of information about fitness and other health indicators in women from countries such as Morocco. This study aims to explore the association of weight status with physical and mental health in Moroccan perimenopausal women. Methods 151 women (45-65 years) from the North of Morocco were analyzed by standardized field-based fitness tests to assess cardiorespiratory fitness, muscular strength, flexibility, agility and balance. Quality of life was assessed by means of the Short-Form-36 Health Survey. Resting heart rate, blood pressure and plasma fasting glucose, total cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides were also measured. Results Blood pressure (P=0.001), plasma triglycerides (P=0.041) and the prevalence of metabolic syndrome (P<0.001) increased as weight status increased. Levels of cardiorespiratory fitness, upper-body flexibility (both, P<0.001), static balance (P<0.05) and dynamic balance (P<0.01) decreased as weight status increased. Pairwise comparisons showed differences mainly between normal-weight and overweight vs. obese groups. No differences between groups were observed on quality of life. Conclusion Cardiovascular and lipid profile and fitness, important indicators of cardiovascular disease risk, worsened as weight status increased, whereas quality of life appears to be independent of weight status. Exercise and nutritional programs focus on weight management may be advisable in this under studied population. PMID:27303571

The Role of Flexibility and Conformational Selection in the Binding Promiscuity of PDZ Domains

PubMed Central

Münz, Márton; Hein, Jotun; Biggin, Philip C.

2012-01-01

In molecular recognition, it is often the case that ligand binding is coupled to conformational change in one or both of the binding partners. Two hypotheses describe the limiting cases involved; the first is the induced fit and the second is the conformational selection model. The conformational selection model requires that the protein adopts conformations that are similar to the ligand-bound conformation in the absence of ligand, whilst the induced-fit model predicts that the ligand-bound conformation of the protein is only accessible when the ligand is actually bound. The flexibility of the apo protein clearly plays a major role in these interpretations. For many proteins involved in signaling pathways there is the added complication that they are often promiscuous in that they are capable of binding to different ligand partners. The relationship between protein flexibility and promiscuity is an area of active research and is perhaps best exemplified by the PDZ domain family of proteins. In this study we use molecular dynamics simulations to examine the relationship between flexibility and promiscuity in five PDZ domains: the human Dvl2 (Dishevelled-2) PDZ domain, the human Erbin PDZ domain, the PDZ1 domain of InaD (inactivation no after-potential D protein) from fruit fly, the PDZ7 domain of GRIP1 (glutamate receptor interacting protein 1) from rat and the PDZ2 domain of PTP-BL (protein tyrosine phosphatase) from mouse. We show that despite their high structural similarity, the PDZ binding sites have significantly different dynamics. Importantly, the degree of binding pocket flexibility was found to be closely related to the various characteristics of peptide binding specificity and promiscuity of the five PDZ domains. Our findings suggest that the intrinsic motions of the apo structures play a key role in distinguishing functional properties of different PDZ domains and allow us to make predictions that can be experimentally tested. PMID:23133356

Non-linearity of the collagen triple helix in solution and implications for collagen function.

PubMed

Walker, Kenneth T; Nan, Ruodan; Wright, David W; Gor, Jayesh; Bishop, Anthony C; Makhatadze, George I; Brodsky, Barbara; Perkins, Stephen J

2017-06-16

Collagen adopts a characteristic supercoiled triple helical conformation which requires a repeating (Xaa-Yaa-Gly) n sequence. Despite the abundance of collagen, a combined experimental and atomistic modelling approach has not so far quantitated the degree of flexibility seen experimentally in the solution structures of collagen triple helices. To address this question, we report an experimental study on the flexibility of varying lengths of collagen triple helical peptides, composed of six, eight, ten and twelve repeats of the most stable Pro-Hyp-Gly (POG) units. In addition, one unblocked peptide, (POG) 10unblocked , was compared with the blocked (POG) 10 as a control for the significance of end effects. Complementary analytical ultracentrifugation and synchrotron small angle X-ray scattering data showed that the conformations of the longer triple helical peptides were not well explained by a linear structure derived from crystallography. To interpret these data, molecular dynamics simulations were used to generate 50 000 physically realistic collagen structures for each of the helices. These structures were fitted against their respective scattering data to reveal the best fitting structures from this large ensemble of possible helix structures. This curve fitting confirmed a small degree of non-linearity to exist in these best fit triple helices, with the degree of bending approximated as 4-17° from linearity. Our results open the way for further studies of other collagen triple helices with different sequences and stabilities in order to clarify the role of molecular rigidity and flexibility in collagen extracellular and immune function and disease. © 2017 The Author(s).

Computational Fluid Dynamics Analysis of Flexible Duct Junction Box Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beach, Robert; Prahl, Duncan; Lange, Rich

2013-12-01

IBACOS explored the relationships between pressure and physical configurations of flexible duct junction boxes by using computational fluid dynamics (CFD) simulations to predict individual box parameters and total system pressure, thereby ensuring improved HVAC performance. Current Air Conditioning Contractors of America (ACCA) guidance (Group 11, Appendix 3, ACCA Manual D, Rutkowski 2009) allows for unconstrained variation in the number of takeoffs, box sizes, and takeoff locations. The only variables currently used in selecting an equivalent length (EL) are velocity of air in the duct and friction rate, given the first takeoff is located at least twice its diameter away frommore » the inlet. This condition does not account for other factors impacting pressure loss across these types of fittings. For each simulation, the IBACOS team converted pressure loss within a box to an EL to compare variation in ACCA Manual D guidance to the simulated variation. IBACOS chose cases to represent flows reasonably correlating to flows typically encountered in the field and analyzed differences in total pressure due to increases in number and location of takeoffs, box dimensions, and velocity of air, and whether an entrance fitting is included. The team also calculated additional balancing losses for all cases due to discrepancies between intended outlet flows and natural flow splits created by the fitting. In certain asymmetrical cases, the balancing losses were significantly higher than symmetrical cases where the natural splits were close to the targets. Thus, IBACOS has shown additional design constraints that can ensure better system performance.« less

BGFit: management and automated fitting of biological growth curves.

PubMed

Veríssimo, André; Paixão, Laura; Neves, Ana Rute; Vinga, Susana

2013-09-25

Existing tools to model cell growth curves do not offer a flexible integrative approach to manage large datasets and automatically estimate parameters. Due to the increase of experimental time-series from microbiology and oncology, the need for a software that allows researchers to easily organize experimental data and simultaneously extract relevant parameters in an efficient way is crucial. BGFit provides a web-based unified platform, where a rich set of dynamic models can be fitted to experimental time-series data, further allowing to efficiently manage the results in a structured and hierarchical way. The data managing system allows to organize projects, experiments and measurements data and also to define teams with different editing and viewing permission. Several dynamic and algebraic models are already implemented, such as polynomial regression, Gompertz, Baranyi, Logistic and Live Cell Fraction models and the user can add easily new models thus expanding current ones. BGFit allows users to easily manage their data and models in an integrated way, even if they are not familiar with databases or existing computational tools for parameter estimation. BGFit is designed with a flexible architecture that focus on extensibility and leverages free software with existing tools and methods, allowing to compare and evaluate different data modeling techniques. The application is described in the context of bacterial and tumor cells growth data fitting, but it is also applicable to any type of two-dimensional data, e.g. physical chemistry and macroeconomic time series, being fully scalable to high number of projects, data and model complexity.

Decrypting the structural, dynamic, and energetic basis of a monomeric kinesin interacting with a tubulin dimer in three ATPase states by all-atom molecular dynamics simulation.

PubMed

Chakraborty, Srirupa; Zheng, Wenjun

2015-01-27

We have employed molecular dynamics (MD) simulation to investigate, with atomic details, the structural dynamics and energetics of three major ATPase states (ADP, APO, and ATP state) of a human kinesin-1 monomer in complex with a tubulin dimer. Starting from a recently solved crystal structure of ATP-like kinesin-tubulin complex by the Knossow lab, we have used flexible fitting of cryo-electron-microscopy maps to construct new structural models of the kinesin-tubulin complex in APO and ATP state, and then conducted extensive MD simulations (total 400 ns for each state), followed by flexibility analysis, principal component analysis, hydrogen bond analysis, and binding free energy analysis. Our modeling and simulation have revealed key nucleotide-dependent changes in the structure and flexibility of the nucleotide-binding pocket (featuring a highly flexible and open switch I in APO state) and the tubulin-binding site, and allosterically coupled motions driving the APO to ATP transition. In addition, our binding free energy analysis has identified a set of key residues involved in kinesin-tubulin binding. On the basis of our simulation, we have attempted to address several outstanding issues in kinesin study, including the possible roles of β-sheet twist and neck linker docking in regulating nucleotide release and binding, the structural mechanism of ADP release, and possible extension and shortening of α4 helix during the ATPase cycle. This study has provided a comprehensive structural and dynamic picture of kinesin's major ATPase states, and offered promising targets for future mutational and functional studies to investigate the molecular mechanism of kinesin motors.

Diffusion of molecules and macromolecules in thylakoid membranes.

PubMed

Kirchhoff, Helmut

2014-04-01

The survival and fitness of photosynthetic organisms is critically dependent on the flexible response of the photosynthetic machinery, harbored in thylakoid membranes, to environmental changes. A central element of this flexibility is the lateral diffusion of membrane components along the membrane plane. As demonstrated, almost all functions of photosynthetic energy conversion are dependent on lateral diffusion. The mobility of both small molecules (plastoquinone, xanthophylls) as well as large protein supercomplexes is very sensitive to changes in structural boundary conditions. Knowledge about the design principles that govern the mobility of photosynthetic membrane components is essential to understand the dynamic response of the photosynthetic machinery. This review summarizes our knowledge about the factors that control diffusion in thylakoid membranes and bridges structural membrane alterations to changes in mobility and function. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components. Copyright © 2013 Elsevier B.V. All rights reserved.

Effects of Mat Pilates on Physical Functional Performance of Older Adults: A Meta-analysis of Randomized Controlled Trials.

PubMed

Bueno de Souza, Roberta Oliveira; Marcon, Liliane de Faria; Arruda, Alex Sandro Faria de; Pontes Junior, Francisco Luciano; Melo, Ruth Caldeira de

2018-06-01

The present meta-analysis aimed to examine evidence from randomized controlled trials to determine the effects of mat Pilates on measures of physical functional performance in the older population. A search was conducted in the MEDLINE/PubMed, Scopus, Scielo, and PEDro databases between February and March 2017. Only randomized controlled trials that were written in English, included subjects aged 60 yrs who used mat Pilates exercises, included a comparison (control) group, and reported performance-based measures of physical function (balance, flexibility, muscle strength, and cardiorespiratory fitness) were included. The methodological quality of the studies was analyzed according to the PEDro scale and the best-evidence synthesis. The meta-analysis was conducted with the Review Manager 5.3 software. The search retrieved 518 articles, nine of which fulfilled the inclusion criteria. High methodological quality was found in five of these studies. Meta-analysis indicated a large effect of mat Pilates on dynamic balance (standardized mean difference = 1.10, 95% confidence interval = 0.29-1.90), muscle strength (standardized mean difference = 1.13, 95% confidence interval = 0.30-1.96), flexibility (standardized mean difference = 1.22, 95% confidence interval = 0.39-2.04), and cardiorespiratory fitness (standardized mean difference = 1.48, 95% confidence interval = 0.42-2.54) of elderly subjects. There is evidence that mat Pilates improves dynamic balance, lower limb strength, hip and lower back flexibility, and cardiovascular endurance in elderly individuals. Furthermore, high-quality studies are necessary to clarify the effects of mat Pilates on other physical functional measurements among older adults.

An access control model with high security for distributed workflow and real-time application

NASA Astrophysics Data System (ADS)

Han, Ruo-Fei; Wang, Hou-Xiang

2007-11-01

The traditional mandatory access control policy (MAC) is regarded as a policy with strict regulation and poor flexibility. The security policy of MAC is so compelling that few information systems would adopt it at the cost of facility, except some particular cases with high security requirement as military or government application. However, with the increasing requirement for flexibility, even some access control systems in military application have switched to role-based access control (RBAC) which is well known as flexible. Though RBAC can meet the demands for flexibility but it is weak in dynamic authorization and consequently can not fit well in the workflow management systems. The task-role-based access control (T-RBAC) is then introduced to solve the problem. It combines both the advantages of RBAC and task-based access control (TBAC) which uses task to manage permissions dynamically. To satisfy the requirement of system which is distributed, well defined with workflow process and critically for time accuracy, this paper will analyze the spirit of MAC, introduce it into the improved T&RBAC model which is based on T-RBAC. At last, a conceptual task-role-based access control model with high security for distributed workflow and real-time application (A_T&RBAC) is built, and its performance is simply analyzed.

Caudate Nucleus Volume Mediates the Link between Cardiorespiratory Fitness and Cognitive Flexibility in Older Adults

PubMed Central

Verstynen, Timothy D.; Lynch, Brighid; Miller, Destiny L.; Voss, Michelle W.; Prakash, Ruchika Shaurya; Chaddock, Laura; Basak, Chandramallika; Szabo, Amanda; Olson, Erin A.; Wojcicki, Thomas R.; Fanning, Jason; Gothe, Neha P.; McAuley, Edward; Kramer, Arthur F.; Erickson, Kirk I.

2012-01-01

The basal ganglia play a central role in regulating the response selection abilities that are critical for mental flexibility. In neocortical areas, higher cardiorespiratory fitness levels are associated with increased gray matter volume, and these volumetric differences mediate enhanced cognitive performance in a variety of tasks. Here we examine whether cardiorespiratory fitness correlates with the volume of the subcortical nuclei that make up the basal ganglia and whether this relationship predicts cognitive flexibility in older adults. Structural MRI was used to determine the volume of the basal ganglia nuclei in a group of older, neurologically healthy individuals (mean age 66 years, N = 179). Measures of cardiorespiratory fitness (VO2max), cognitive flexibility (task switching), and attentional control (flanker task) were also collected. Higher fitness levels were correlated with higher accuracy rates in the Task Switching paradigm. In addition, the volume of the caudate nucleus, putamen, and globus pallidus positively correlated with Task Switching accuracy. Nested regression modeling revealed that caudate nucleus volume was a significant mediator of the relationship between cardiorespiratory fitness, and task switching performance. These findings indicate that higher cardiorespiratory fitness predicts better cognitive flexibility in older adults through greater grey matter volume in the dorsal striatum. PMID:22900181

Executive function moderates the role of muscular fitness in determining functional mobility in older adults.

PubMed

Forte, Roberta; Pesce, Caterina; Leite, Joao Costa; De Vito, Giuseppe; Gibney, Eileen R; Tomporowski, Phillip D; Boreham, Colin A G

2013-06-01

Both physical and cognitive factors are known to independently predict functional mobility in older people. However, the combined predictive value of both physical fitness and cognitive factors on functional mobility has been less investigated. The aim of the present study was to assess if cognitive executive functions moderate the role of physical fitness in determining functional mobility of older individuals. Fifty-seven 65- to 75-year-old healthy participants performed tests of functional mobility (habitual and maximal walking speed, maximal walking speed while picking up objects/stepping over obstacles), physical fitness (peak power, knee extensors torque, back/lower limb flexibility, aerobic fitness), and executive function (inhibition and cognitive flexibility). Maximal walking speeds were predicted by physical fitness parameters and their interaction with cognitive factors. Knee extensor torque emerged as the main predictor of all tested locomotor performances at maximal speed. The effect of peak power and back/lower limb flexibility was moderated by executive functions. In particular, inhibition and cognitive flexibility differed in the way in which they moderate the role of fitness. High levels of cognitive flexibility seem necessary to take advantage of leg power for walking at maximal speed. In contrast, high levels of inhibitory capacity seem to compensate for low levels of back/lower limb flexibility when picking up movements are added to a locomotor task. These findings may have important practical implications for the design and implementation of multi-component training programs aimed at optimizing functional abilities in older adults.

Physical fitness assessment: an update.

PubMed

Wilder, Robert P; Greene, Jill Amanda; Winters, Kathryne L; Long, William B; Gubler, K; Edlich, Richard F

2006-01-01

The American College of Sports Medicine (ACSM) gives the following definition of health-related physical fitness: Physical fitness is defined as a set of attributes that people have or achieve that relates to the ability to perform physical activity. It is also characterized by (1) an ability to perform daily activities with vigor, and (2) a demonstration of traits and capacities that are associated with a low risk of premature development of hypokinetic diseases (e.g., those associated with physical inactivity). Information from an individual's health and medical records can be combined with information from physical fitness assessment to meet the specific health goals and rehabilitative needs of that individual. Attaining adequate informed consent from participants prior to exercise testing is mandatory because of ethical and legal considerations.A physical fitness assessment includes measures of body composition, cardiorespiratory endurance, muscular fitness, and musculoskeletal flexibility. The three common techniques for assessing body composition are hydrostatic weighing, and skinfold measurements, and anthropometric measurements. Cardiorespiratory endurance is a crucial component of physical fitness assessment because of its strong correlation with health and health risks. Maximal oxygen uptake (VO2max) is the traditionally accepted criterion for measuring cardiorespiratory endurance. Although maximal-effort tests must be used to measure VO2max, submaximal exercise can be used to estimate this value. Muscular fitness has historically been used to describe an individual's integrated status of muscular strength and muscular endurance. An individual's muscular strength is specific to a particular muscle or muscle group and refers to the maximal force (N or kg) that the muscle or muscle group can generate. Dynamic strength can be assessed by measuring the movement of an individual's body against an external load. Isokinetic testing may be performed by assessing the muscle tension generated throughout a range of motion at a constant angular velocity. The ability of a muscle group to perform repeated contractions over a specific period of time that is sufficient to cause fatigue is termed muscular endurance. Musculoskeletal flexibility evaluations focus on the joints and associated structures, ligaments, and muscles that cross the joints. The sit-and-reach test and the behind-the-back reach test satisfy many of the criteria for physical assessment of musculoskeletal flexibility. A physical fitness assessment must be integrated into all activities of daily living, as well as the physician's examination, to assess and promote health.

Advanced ensemble modelling of flexible macromolecules using X-ray solution scattering.

PubMed

Tria, Giancarlo; Mertens, Haydyn D T; Kachala, Michael; Svergun, Dmitri I

2015-03-01

Dynamic ensembles of macromolecules mediate essential processes in biology. Understanding the mechanisms driving the function and molecular interactions of 'unstructured' and flexible molecules requires alternative approaches to those traditionally employed in structural biology. Small-angle X-ray scattering (SAXS) is an established method for structural characterization of biological macromolecules in solution, and is directly applicable to the study of flexible systems such as intrinsically disordered proteins and multi-domain proteins with unstructured regions. The Ensemble Optimization Method (EOM) [Bernadó et al. (2007 ▶). J. Am. Chem. Soc. 129, 5656-5664] was the first approach introducing the concept of ensemble fitting of the SAXS data from flexible systems. In this approach, a large pool of macromolecules covering the available conformational space is generated and a sub-ensemble of conformers coexisting in solution is selected guided by the fit to the experimental SAXS data. This paper presents a series of new developments and advancements to the method, including significantly enhanced functionality and also quantitative metrics for the characterization of the results. Building on the original concept of ensemble optimization, the algorithms for pool generation have been redesigned to allow for the construction of partially or completely symmetric oligomeric models, and the selection procedure was improved to refine the size of the ensemble. Quantitative measures of the flexibility of the system studied, based on the characteristic integral parameters of the selected ensemble, are introduced. These improvements are implemented in the new EOM version 2.0, and the capabilities as well as inherent limitations of the ensemble approach in SAXS, and of EOM 2.0 in particular, are discussed.

An Elastic Tube Gage for Measuring Static and Dynamic Pressures

DTIC Science & Technology

1948-05-01

AUXILIARY HEAT RADIATORS - .-. • • /•’ • • • AUXILIARY ELECTRICAL AND RECORDING EQUIPMENT . . . . .. RESULTS OF FIELD TESTS...time and resources and to permit a greater flexibility in use where measurements are required of a large number or variety of quantities.. Since...gages are first prercürved to fit the tube., and then cemented with Duco. After air-drying for H8 hours, the gages, are heated with infrared lamps to

Duct Joining System

DOEpatents

Proctor, John P.

2001-02-27

A duct joining system for providing an air-tight seal and mechanical connection for ducts and fittings is disclosed. The duct joining system includes a flexible gasket affixed to a male end of a duct or fitting. The flexible gasket is affixed at an angle relative to normal of the male end of the duct. The female end of the other duct includes a raised bead in which the flexible gasket is seated when the ducts are properly joined. The angled flexible gasket seated in the raised bead forms an air-tight seal as well as fastens or locks the male end to the female end. Alternatively, when a flexible duct is used, a band clamp with a raised bead is clamped over the female end of the flexible duct and over the male end of a fitting to provide an air tight seal and fastened connection.

Duct joining system

DOEpatents

Proctor, John P.; deKieffer, Robert C.

2001-01-01

A duct joining system for providing an air-tight seal and mechanical connection for ducts and fittings is disclosed. The duct joining system includes a flexible gasket affixed to a male end of a duct or fitting. The flexible gasket is affixed at an angle relative to normal of the male end of the duct. The female end of the other duct includes a raised bead in which the flexible gasket is seated when the ducts are properly joined. The angled flexible gasket seated in the raised bead forms an air-tight seal as well as fastens or locks the male end to the female end. Alternatively, when a flexible duct is used, a band clamp with a raised bead is clamped over the female end of the flexible duct and over the male end of a fitting to provide an air tight seal and fastened connection.

Method and apparatus for air-coupled transducer

NASA Technical Reports Server (NTRS)

Song, Junho (Inventor); Chimenti, Dale E. (Inventor)

2010-01-01

An air-coupled transducer includes a ultrasonic transducer body having a radiation end with a backing fixture at the radiation end. There is a flexible backplate conformingly fit to the backing fixture and a thin membrane (preferably a metallized polymer) conformingly fit to the flexible backplate. In one embodiment, the backing fixture is spherically curved and the flexible backplate is spherically curved. The flexible backplate is preferably patterned with pits or depressions.

Principal component analysis of molecular dynamics: On the use of Cartesian vs. internal coordinates

NASA Astrophysics Data System (ADS)

Sittel, Florian; Jain, Abhinav; Stock, Gerhard

2014-07-01

Principal component analysis of molecular dynamics simulations is a popular method to account for the essential dynamics of the system on a low-dimensional free energy landscape. Using Cartesian coordinates, first the translation and overall rotation need to be removed from the trajectory. Since the rotation depends via the moment of inertia on the molecule's structure, this separation is only straightforward for relatively rigid systems. Adopting millisecond molecular dynamics simulations of the folding of villin headpiece and the functional dynamics of BPTI provided by D. E. Shaw Research, it is demonstrated via a comparison of local and global rotational fitting that the structural dynamics of flexible molecules necessarily results in a mixing of overall and internal motion. Even for the small-amplitude functional motion of BPTI, the conformational distribution obtained from a Cartesian principal component analysis therefore reflects to some extend the dominant overall motion rather than the much smaller internal motion of the protein. Internal coordinates such as backbone dihedral angles, on the other hand, are found to yield correct and well-resolved energy landscapes for both examples. The virtues and shortcomings of the choice of various fitting schemes and coordinate sets as well as the generality of these results are discussed in some detail.

Principal component analysis of molecular dynamics: on the use of Cartesian vs. internal coordinates.

PubMed

Sittel, Florian; Jain, Abhinav; Stock, Gerhard

2014-07-07

Principal component analysis of molecular dynamics simulations is a popular method to account for the essential dynamics of the system on a low-dimensional free energy landscape. Using Cartesian coordinates, first the translation and overall rotation need to be removed from the trajectory. Since the rotation depends via the moment of inertia on the molecule's structure, this separation is only straightforward for relatively rigid systems. Adopting millisecond molecular dynamics simulations of the folding of villin headpiece and the functional dynamics of BPTI provided by D. E. Shaw Research, it is demonstrated via a comparison of local and global rotational fitting that the structural dynamics of flexible molecules necessarily results in a mixing of overall and internal motion. Even for the small-amplitude functional motion of BPTI, the conformational distribution obtained from a Cartesian principal component analysis therefore reflects to some extend the dominant overall motion rather than the much smaller internal motion of the protein. Internal coordinates such as backbone dihedral angles, on the other hand, are found to yield correct and well-resolved energy landscapes for both examples. The virtues and shortcomings of the choice of various fitting schemes and coordinate sets as well as the generality of these results are discussed in some detail.

Leaf and stem economics spectra drive diversity of functional plant traits in a dynamic global vegetation model.

PubMed

Sakschewski, Boris; von Bloh, Werner; Boit, Alice; Rammig, Anja; Kattge, Jens; Poorter, Lourens; Peñuelas, Josep; Thonicke, Kirsten

2015-01-22

Functional diversity is critical for ecosystem dynamics, stability and productivity. However, dynamic global vegetation models (DGVMs) which are increasingly used to simulate ecosystem functions under global change, condense functional diversity to plant functional types (PFTs) with constant parameters. Here, we develop an individual- and trait-based version of the DGVM LPJmL (Lund-Potsdam-Jena managed Land) called LPJmL- flexible individual traits (LPJmL-FIT) with flexible individual traits) which we apply to generate plant trait maps for the Amazon basin. LPJmL-FIT incorporates empirical ranges of five traits of tropical trees extracted from the TRY global plant trait database, namely specific leaf area (SLA), leaf longevity (LL), leaf nitrogen content (N area ), the maximum carboxylation rate of Rubisco per leaf area (vcmaxarea), and wood density (WD). To scale the individual growth performance of trees, the leaf traits are linked by trade-offs based on the leaf economics spectrum, whereas wood density is linked to tree mortality. No preselection of growth strategies is taking place, because individuals with unique trait combinations are uniformly distributed at tree establishment. We validate the modeled trait distributions by empirical trait data and the modeled biomass by a remote sensing product along a climatic gradient. Including trait variability and trade-offs successfully predicts natural trait distributions and achieves a more realistic representation of functional diversity at the local to regional scale. As sites of high climatic variability, the fringes of the Amazon promote trait divergence and the coexistence of multiple tree growth strategies, while lower plant trait diversity is found in the species-rich center of the region with relatively low climatic variability. LPJmL-FIT enables to test hypotheses on the effects of functional biodiversity on ecosystem functioning and to apply the DGVM to current challenges in ecosystem management from local to global scales, that is, deforestation and climate change effects. © 2015 John Wiley & Sons Ltd.

An innovative design for using flexible printed coils for magnetostrictive-based longitudinal guided wave sensors in steel strand inspection

NASA Astrophysics Data System (ADS)

Tse, P. W.; Liu, X. C.; Liu, Z. H.; Wu, B.; He, C. F.; Wang, X. J.

2011-05-01

Magnetostrictive sensors (MsSs) that can excite and receive guided waves are commonly used in detecting defects that may occur in cables and strands for supporting heavy structures. A conventional MsS has a hard sensing coil that is wound onto a bobbin with electric wires to generate the necessary dynamic magnetic field to excite the desired guided waves. This tailor-made hard coil is usually bulky and is not flexible enough to fit steel strands of various sizes. The conventional MsS also cannot be mounted to any steel strand that does not have a free end to allow the bobbin to pass through the structure of the tested strand. Such inflexibilities limit the use of conventional MsSs in practical situations. To solve these limitations, an innovative type of coil, called a flexible printed coil (FPC), which is made out of flexible printed film, has been designed to replace the inflexible hard coil. The flexible structure of the FPC ensures that the new MsS can be easily installed on and removed from steel strands with different diameters and without free ends. Moreover, the FPC-based MsS can be wrapped into multiple layers due to its thin and flexible design. Although multi-layer FPC creates a minor asymmetry in the dynamic magnetic field, the results of finite element analysis and experiments confirm that the longitudinal guided waves excited by a FPC-based MsS are comparable to those excited by a conventional hard coil MsS. No significant reduction in defect inspection performance was found; in fact, further advantages were identified when using the FPC-based MsS. When acting as the transmitter, the innovative FPC-based MsS can cover a longer inspection length of strand. When acting as the receiver, the FPC-based MsS is more sensitive to smaller defects that are impossible to detect using a hard coil MsS. Hence, the multi-layer FPC-based MsS has great potential for replacing the conventional hard coil MsS because of its convenient installation, and ease of fitting to different strand diameters; it is smaller, and, most importantly, performs much better in strand defect detection.

Evaluation of the flexibility of protective gloves.

PubMed

Harrabi, Lotfi; Dolez, Patricia I; Vu-Khanh, Toan; Lara, Jaime

2008-01-01

Two mechanical methods have been developed for the characterization of the flexibility of protective gloves, a key factor affecting their degree of usefulness for workers. The principle of the first method is similar to the ASTM D 4032 standard relative to fabric stiffness and simulates the deformations encountered by gloves that are not tight fitted to the hand. The second method characterizes the flexibility of gloves that are worn tight fitted. Its validity was theoretically verified for elastomer materials. Both methods should prove themselves as valuable tools for protective glove manufacturers, allowing for the characterization of their existing products in terms of flexibility and the development of new ones better fitting workers' needs.

ROCKETSHIP: a flexible and modular software tool for the planning, processing and analysis of dynamic MRI studies.

PubMed

Barnes, Samuel R; Ng, Thomas S C; Santa-Maria, Naomi; Montagne, Axel; Zlokovic, Berislav V; Jacobs, Russell E

2015-06-16

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a promising technique to characterize pathology and evaluate treatment response. However, analysis of DCE-MRI data is complex and benefits from concurrent analysis of multiple kinetic models and parameters. Few software tools are currently available that specifically focuses on DCE-MRI analysis with multiple kinetic models. Here, we developed ROCKETSHIP, an open-source, flexible and modular software for DCE-MRI analysis. ROCKETSHIP incorporates analyses with multiple kinetic models, including data-driven nested model analysis. ROCKETSHIP was implemented using the MATLAB programming language. Robustness of the software to provide reliable fits using multiple kinetic models is demonstrated using simulated data. Simulations also demonstrate the utility of the data-driven nested model analysis. Applicability of ROCKETSHIP for both preclinical and clinical studies is shown using DCE-MRI studies of the human brain and a murine tumor model. A DCE-MRI software suite was implemented and tested using simulations. Its applicability to both preclinical and clinical datasets is shown. ROCKETSHIP was designed to be easily accessible for the beginner, but flexible enough for changes or additions to be made by the advanced user as well. The availability of a flexible analysis tool will aid future studies using DCE-MRI. A public release of ROCKETSHIP is available at https://github.com/petmri/ROCKETSHIP .

Poisson property of the occurrence of flip-flops in a model membrane.

PubMed

Arai, Noriyoshi; Akimoto, Takuma; Yamamoto, Eiji; Yasui, Masato; Yasuoka, Kenji

2014-02-14

How do lipid molecules in membranes perform a flip-flop? The flip-flops of lipid molecules play a crucial role in the formation and flexibility of membranes. However, little has been determined about the behavior of flip-flops, either experimentally, or in molecular dynamics simulations. Here, we provide numerical results of the flip-flops of model lipid molecules in a model membrane and investigate the statistical properties, using millisecond-order coarse-grained molecular simulations (dissipative particle dynamics). We find that there are three different ways of flip-flops, which can be clearly characterized by their paths on the free energy surface. Furthermore, we found that the probability of the number of the flip-flops is well fitted by the Poisson distribution, and the probability density function for the inter-occurrence times of flip-flops coincides with that of the forward recurrence times. These results indicate that the occurrence of flip-flops is a Poisson process, which will play an important role in the flexibilities of membranes.

Flexibility in change practices and job outcomes for nurses: exploring the role of subjective fit.

PubMed

Newton, Cameron; Teo, Stephen T T; Pick, David; Yeung, Melissa; Salamonson, Yenna

2013-12-01

To integrate existing theoretical perspectives on change management, subjective fit and occupational stress to better understand the effects of change on employee adjustment. Although subjective fit with organizational goals and objectives has been shown to have positive effects on employee adjustment, its role in the organizational change-occupational stress context is not understood. This represents a caveat in research when considering the notion that those who feel that they fit with the organization's goals may be better equipped to reconcile and deal with change. A cross-sectional survey of nurses from public and non-profit sector hospitals was conducted. Data were collected from 252 public and non-profit sector nurses via online surveys. Data were collected from June-October in 2010. Structural equation modelling was used to test the direct and indirect effects among the focal variables. The results showed that public and non-profit nurses experience flexibility-limiting and flexibility-promoting change initiatives and that these are differentially related to the perception of administrative stressors and adjustment with these relationships directly and indirectly influenced by perceptions of subjective fit. Flexibility-limiting change initiatives led to lower levels of subjective fit, higher levels of administrative stressors and less favourable adjustment. On the other hand, flexibility-promoting change practices led to higher levels of subjective fit, lower levels of administrative stressors and ultimately better adjustment. The results further the theoretical understanding of the role of subjective fit in organizational change and occupational stress theories. © 2013 John Wiley & Sons Ltd.

Effect of the explicit flexibility of the InhA enzyme from Mycobacterium tuberculosis in molecular docking simulations.

PubMed

Cohen, Elisangela M L; Machado, Karina S; Cohen, Marcelo; de Souza, Osmar Norberto

2011-12-22

Protein/receptor explicit flexibility has recently become an important feature of molecular docking simulations. Taking the flexibility into account brings the docking simulation closer to the receptors' real behaviour in its natural environment. Several approaches have been developed to address this problem. Among them, modelling the full flexibility as an ensemble of snapshots derived from a molecular dynamics simulation (MD) of the receptor has proved very promising. Despite its potential, however, only a few studies have employed this method to probe its effect in molecular docking simulations. We hereby use ensembles of snapshots obtained from three different MD simulations of the InhA enzyme from M. tuberculosis (Mtb), the wild-type (InhA_wt), InhA_I16T, and InhA_I21V mutants to model their explicit flexibility, and to systematically explore their effect in docking simulations with three different InhA inhibitors, namely, ethionamide (ETH), triclosan (TCL), and pentacyano(isoniazid)ferrate(II) (PIF). The use of fully-flexible receptor (FFR) models of InhA_wt, InhA_I16T, and InhA_I21V mutants in docking simulation with the inhibitors ETH, TCL, and PIF revealed significant differences in the way they interact as compared to the rigid, InhA crystal structure (PDB ID: 1ENY). In the latter, only up to five receptor residues interact with the three different ligands. Conversely, in the FFR models this number grows up to an astonishing 80 different residues. The comparison between the rigid crystal structure and the FFR models showed that the inclusion of explicit flexibility, despite the limitations of the FFR models employed in this study, accounts in a substantial manner to the induced fit expected when a protein/receptor and ligand approach each other to interact in the most favourable manner. Protein/receptor explicit flexibility, or FFR models, represented as an ensemble of MD simulation snapshots, can lead to a more realistic representation of the induced fit effect expected in the encounter and proper docking of receptors to ligands. The FFR models of InhA explicitly characterizes the overall movements of the amino acid residues in helices, strands, loops, and turns, allowing the ligand to properly accommodate itself in the receptor's binding site. Utilization of the intrinsic flexibility of Mtb's InhA enzyme and its mutants in virtual screening via molecular docking simulation may provide a novel platform to guide the rational or dynamical-structure-based drug design of novel inhibitors for Mtb's InhA. We have produced a short video sequence of each ligand (ETH, TCL and PIF) docked to the FFR models of InhA_wt. These videos are available at http://www.inf.pucrs.br/~osmarns/LABIO/Videos_Cohen_et_al_19_07_2011.htm.

The functional fitness capacity of adults with Down syndrome in South Africa.

PubMed

Terblanche, E; Boer, P-H

2013-09-01

It is well established that there is a relationship between physical inactivity and increased risk for diseases of lifestyle. Persons with Down syndrome (DS) are especially at risk because of physical and health impairments, as well as perceived and real barriers to participation in exercise. The purpose of the study was to establish the functional fitness capacity and predictors of performance of DS adults. Data were collected at various intellectual disability centres and private homes in seven provinces of South Africa. Three hundred and seventy-one DS individuals (199 men and 172 women) from 18 to 66 years were tested for balance, flexibility, coordination, muscular strength and endurance, aerobic capacity and functional ability. Data were categorised according to gender and age groups (18-25, 26-35, 36-45, and >45 years). Multiple regression analysis was performed to determine the relationship between the functional task and physical test items. Down syndrome men performed significantly better on all but two tests compared with the women (P < 0.05). DS women performed better on the sit-and-reach flexibility item and the chair stand test; however, differences were not statistically significant from the men. Significant differences across age groups were observed for nine of the 13 functional fitness tests (P < 0.05). Muscular strength items, especially leg strength, significantly predicted functional performance in DS men and women. Aerobic capacity only predicted functional performance in DS men and sit-and-reach flexibility and dynamic balance only in DS women. Findings of this study provide important information on the functional capacity of DS adults and show which physical attributes contribute to functional performance. Consequently appropriate training programmes can be tailored for this population whom is known to have poor functional fitness. © 2012 The Authors. Journal of Intellectual Disability Research © 2012 John Wiley & Sons Ltd, MENCAP & IASSID.

Combined approaches to flexible fitting and assessment in virus capsids undergoing conformational change☆

PubMed Central

Pandurangan, Arun Prasad; Shakeel, Shabih; Butcher, Sarah Jane; Topf, Maya

2014-01-01

Fitting of atomic components into electron cryo-microscopy (cryoEM) density maps is routinely used to understand the structure and function of macromolecular machines. Many fitting methods have been developed, but a standard protocol for successful fitting and assessment of fitted models has yet to be agreed upon among the experts in the field. Here, we created and tested a protocol that highlights important issues related to homology modelling, density map segmentation, rigid and flexible fitting, as well as the assessment of fits. As part of it, we use two different flexible fitting methods (Flex-EM and iMODfit) and demonstrate how combining the analysis of multiple fits and model assessment could result in an improved model. The protocol is applied to the case of the mature and empty capsids of Coxsackievirus A7 (CAV7) by flexibly fitting homology models into the corresponding cryoEM density maps at 8.2 and 6.1 Å resolution. As a result, and due to the improved homology models (derived from recently solved crystal structures of a close homolog – EV71 capsid – in mature and empty forms), the final models present an improvement over previously published models. In close agreement with the capsid expansion observed in the EV71 structures, the new CAV7 models reveal that the expansion is accompanied by ∼5° counterclockwise rotation of the asymmetric unit, predominantly contributed by the capsid protein VP1. The protocol could be applied not only to viral capsids but also to many other complexes characterised by a combination of atomic structure modelling and cryoEM density fitting. PMID:24333899

Utilization of Solar Dynamics Observatory space weather digital image data for comparative analysis with application to Baryon Oscillation Spectroscopic Survey

NASA Astrophysics Data System (ADS)

Shekoyan, V.; Dehipawala, S.; Liu, Ernest; Tulsee, Vivek; Armendariz, R.; Tremberger, G.; Holden, T.; Marchese, P.; Cheung, T.

2012-10-01

Digital solar image data is available to users with access to standard, mass-market software. Many scientific projects utilize the Flexible Image Transport System (FITS) format, which requires specialized software typically used in astrophysical research. Data in the FITS format includes photometric and spatial calibration information, which may not be useful to researchers working with self-calibrated, comparative approaches. This project examines the advantages of using mass-market software with readily downloadable image data from the Solar Dynamics Observatory for comparative analysis over with the use of specialized software capable of reading data in the FITS format. Comparative analyses of brightness statistics that describe the solar disk in the study of magnetic energy using algorithms included in mass-market software have been shown to give results similar to analyses using FITS data. The entanglement of magnetic energy associated with solar eruptions, as well as the development of such eruptions, has been characterized successfully using mass-market software. The proposed algorithm would help to establish a publicly accessible, computing network that could assist in exploratory studies of all FITS data. The advances in computer, cell phone and tablet technology could incorporate such an approach readily for the enhancement of high school and first-year college space weather education on a global scale. Application to ground based data such as that contained in the Baryon Oscillation Spectroscopic Survey is discussed.

Quantification of rectifications for the Northwestern University Flexible Sub-Ischial Vacuum Socket.

PubMed

Fatone, Stefania; Johnson, William Brett; Tran, Lilly; Tucker, Kerice; Mowrer, Christofer; Caldwell, Ryan

2017-06-01

The fit and function of a prosthetic socket depend on the prosthetist's ability to design the socket's shape to distribute load comfortably over the residual limb. We recently developed a sub-ischial socket for persons with transfemoral amputation: the Northwestern University Flexible Sub-Ischial Vacuum Socket. This study aimed to quantify the rectifications required to fit the Northwestern University Flexible Sub-Ischial Vacuum Socket to teach the technique to prosthetists as well as provide a computer-aided design-computer-aided manufacturing option. Development project. A program was used to align scans of unrectified and rectified negative molds and calculate shape change as a result of rectification. Averaged rectifications were used to create a socket template, which was shared with a central fabrication facility engaged in provision of Northwestern University Flexible Sub-Ischial Vacuum Sockets to early clinical adopters. Feedback regarding quality of fitting was obtained. Rectification maps created from 30 cast pairs of successfully fit Northwestern University Flexible Sub-Ischial Vacuum Sockets confirmed that material was primarily removed from the positive mold in the proximal-lateral and posterior regions. The template was used to fabricate check sockets for 15 persons with transfemoral amputation. Feedback suggested that the template provided a reasonable initial fit with only minor adjustments. Rectification maps and template were used to facilitate teaching and central fabrication of the Northwestern University Flexible Sub-Ischial Vacuum Socket. Minor issues with quality of initial fit achieved with the template may be due to inability to adjust the template to patient characteristics (e.g. tissue type, limb shape) and/or the degree to which it represented a fully mature version of the technique. Clinical relevance Rectification maps help communicate an important step in the fabrication of the Northwestern University Flexible Sub-Ischial Vacuum Socket facilitating dissemination of the technique, while the average template provides an alternative fabrication option via computer-aided design-computer-aided manufacturing and central fabrication.

46 CFR 28.835 - Fuel systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... flexible tubing or hose is permitted in the fuel supply line at or near the engine to prevent damage by vibration. If nonmetallic flexible hose is used it must: (1) Not exceed the minimum length needed to allow... with wire braid; (4) Be fitted with suitable, corrosion resistant, compression fittings; and (5) Be...

46 CFR 28.835 - Fuel systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... flexible tubing or hose is permitted in the fuel supply line at or near the engine to prevent damage by vibration. If nonmetallic flexible hose is used it must: (1) Not exceed the minimum length needed to allow... with wire braid; (4) Be fitted with suitable, corrosion resistant, compression fittings; and (5) Be...

46 CFR 28.835 - Fuel systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... flexible tubing or hose is permitted in the fuel supply line at or near the engine to prevent damage by vibration. If nonmetallic flexible hose is used it must: (1) Not exceed the minimum length needed to allow... with wire braid; (4) Be fitted with suitable, corrosion resistant, compression fittings; and (5) Be...

46 CFR 28.835 - Fuel systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... flexible tubing or hose is permitted in the fuel supply line at or near the engine to prevent damage by vibration. If nonmetallic flexible hose is used it must: (1) Not exceed the minimum length needed to allow... with wire braid; (4) Be fitted with suitable, corrosion resistant, compression fittings; and (5) Be...

Flexibility is associated with motor competence in schoolchildren.

PubMed

Lopes, L; Póvoas, S; Mota, J; Okely, A D; Coelho-E-Silva, M J; Cliff, D P; Lopes, V P; Santos, R

2017-12-01

Available data on the associations between motor competence (MC) and flexibility are limited and result inconclusive. This study aims to examine the relationship between flexibility and MC in children. The sample comprised 596 Portuguese children (47.1% girls) aged 9.7 ± 0.6 years. Motor competence was evaluated with the body coordination test, Körperkoordination Test für Kinder. Cardiorespiratory fitness (20-m shuttle run), muscular strength (curl-up and push-up tests), and flexibility (back-saver sit and reach and trunk-lift tests) were evaluated using the Fitnessgram Test Battery. Z-scores by age and gender for the physical fitness tests were constructed. Analysis of variance and regression analysis were performed. Participants in the healthy zone groups of both flexibility tests exhibited significantly better scores of MC than the participants under the healthy zone (P < 0.001). Back-saver sit and reach and trunk-lift Z-scores, either individually or as a sum, were significant predictors of MC (P < 0.05 for all) after adjustments for the other physical fitness components, age, body mass index, and socioeconomic status, in both genders. Our findings highlight the importance of promoting and developing flexibility, as well as the other health-related physical fitness components in schoolchildren to reach adequate levels of MC. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Approximate Dynamic Programming for Military Resource Allocation

DTIC Science & Technology

2014-12-26

difference in means for W = 200, T = 200 ( c ) W = 200, T = 200 5 10 15 20 25 30 35 40 45 50 −2 0 2 4 6 8 Problem Number M ea n A D P − M ea n M M R 95...will provide analysts with a means for effectively determining which weapons concepts to explore further, how to appropriately fit a set of aircraft ...which optimization of the multi-stage DWTA is used to determine optimal weaponeering of aircraft . Because of its flexibility and applicability to

A numerical scheme for the identification of hybrid systems describing the vibration of flexible beams with tip bodies

NASA Technical Reports Server (NTRS)

Rosen, I. G.

1984-01-01

A cubic spline based Galerkin-like method is developed for the identification of a class of hybrid systems which describe the transverse vibration to flexible beams with attached tip bodies. The identification problem is formulated as a least squares fit to data subject to the system dynamics given by a coupled system of ordnary and partial differential equations recast as an abstract evolution equation (AEE) in an appropriate infinite dimensional Hilbert space. Projecting the AEE into spline-based subspaces leads naturally to a sequence of approximating finite dimensional identification problems. The solutions to these problems are shown to exist, are relatively easily computed, and are shown to, in some sense, converge to solutions to the original identification problem. Numerical results for a variety of examples are discussed.

46 CFR 182.455 - Fuel piping.

Code of Federal Regulations, 2010 CFR

2010-10-01

... flow, must be fitted in the fuel supply lines, one at the tank connection and one at the engine end of... flexible hose must be installed in the fuel supply line at or near the engines. The flexible hose must meet... of the engine manufacturer, must be fitted in the fuel supply line in the engine compartment...

How Fit Are Elementary Children in Grades 2-4?

ERIC Educational Resources Information Center

Lemlech, Johanna K.

As part of a Feelin' Good intervention program to improve the physical fitness of children in grades 2 through 4, 603 students were tested for muscle strength and flexibility. Complete pre- and posttest data were obtained from 388 students. Two muscle strength tests and two flexibility tests demonstrated consistent sex differences in performance.…

Fitness as a determinant of arterial stiffness in healthy adult men: a cross-sectional study.

PubMed

Chung, Jinwook; Kim, Milyang; Jin, Youngsoo; Kim, Yonghwan; Hong, Jeeyoung

2018-01-01

Fitness is known to influence arterial stiffness. This study aimed to assess differences in cardiorespiratory endurance, muscular strength, and flexibility according to arterial stiffness, based on sex and age. We enrolled 1590 healthy adults (men: 1242, women: 348) who were free of metabolic syndrome. We measured cardiorespiratory endurance in an exercise stress test on a treadmill, muscular strength by a grip test, and flexibility by upper body forward-bends from a standing position. The brachial-ankle pulse wave velocity test was performed to measure arterial stiffness before the fitness test. Cluster analysis was performed to divide the patients into groups with low (Cluster 1) and high (Cluster 2) arterial stiffness. According to the k-cluster analysis results, Cluster 1 included 624 men and 180 women, and Cluster 2 included 618 men and 168 women. Men in the middle-aged group with low arterial stiffness demonstrated higher cardiorespiratory endurance, muscular strength, and flexibility than those with high arterial stiffness. Similarly, among men in the old-aged group, the cardiorespiratory endurance and muscular strength, but not flexibility, differed significantly according to arterial stiffness. Women in both clusters showed similar cardiorespiratory endurance, muscular strength, and flexibility regardless of their arterial stiffness. Among healthy adults, arterial stiffness was inversely associated with fitness in men but not in women. Therefore, fitness seems to be a determinant for arterial stiffness in men. Additionally, regular exercise should be recommended for middle-aged men to prevent arterial stiffness.

Comparison of physical fitness between rice farmers with and without chronic low back pain: a cross-sectional study.

PubMed

Taechasubamorn, Panada; Nopkesorn, Tawesak; Pannarunothai, Supasit

2010-12-01

To compare physical fitness between rice farmers with chronic low back pain (CLBP) and a healthy control group. Sixty-eight rice farmers with CLBP were matched according to age and sex with healthy farmers. All subjects underwent nine physical fitness tests for body composition, lifting capacity, static back extensor endurance, leg strength, static abdominal endurance, handgrip strength, hamstring flexibility, posterior leg and back muscles flexibility and abdominal flexibility. There was no significant difference between CLBP and healthy groups for all tests, except the static back extensor endurance. The back extensor endurance times of the CLBP group was significantly lower than that of the control group (p = 0.002). Static back extensor endurance is the deficient physical fitness in CLBP rice farmers. Back extensor endurance training should be emphasized in both prevention and rehabilitation programs.

Musculoskeletal Fitness and Risk of Mortality.

ERIC Educational Resources Information Center

Katzmarzyk, Peter T.; Craig, Cora L.

2002-01-01

Quantified the relationship between musculoskeletal fitness and all-cause mortality in Canada, using measures of musculoskeletal fitness (situps, pushups, grip strength, and sit- and-reach trunk flexibility) from adult male and female participants in the Canadian Fitness Survey. Results indicated that some components of musculoskeletal fitness,…

The relationship among physical activity, motor competence and health-related fitness in 14-year-old adolescents.

PubMed

Hands, B; Larkin, D; Parker, H; Straker, L; Perry, M

2009-10-01

Physical activity, physical fitness and motor competence are important health-related constructs. However, the relationship among them, particularly for 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 14.06 years. 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.

Active vibration control techniques for flexible space structures

NASA Technical Reports Server (NTRS)

Parlos, Alexander G.; Jayasuriya, Suhada

1990-01-01

Two proposed control system design techniques for active vibration control in flexible space structures are detailed. Control issues relevant only to flexible-body dynamics are addressed, whereas no attempt was made to integrate the flexible and rigid-body spacecraft dynamics. Both of the proposed approaches revealed encouraging results; however, further investigation of the interaction of the flexible and rigid-body dynamics is warranted.

Reduced flexibility associated with metabolic syndrome in community-dwelling elders.

PubMed

Chang, Ke-Vin; Hung, Chen-Yu; Li, Chia-Ming; Lin, Yu-Hung; Wang, Tyng-Guey; Tsai, Keh-Sung; Han, Der-Sheng

2015-01-01

The ageing process may lead to reductions in physical fitness, a known risk factor in the development of metabolic syndrome. The purpose of the current study was to evaluate cross-sectional and combined associations of metabolic syndrome with body composition and physical fitness in a community based geriatric population. A total of 628 community-dwelling elders attending a geriatric health examination were enrolled in the study. The diagnosis of metabolic syndrome was based on the modified National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criterion with Asian cutoff of waist girth was adopted in this study. Body composition was obtained using bioimpedance analysis, and physical fitness was evaluated through the measurement of muscle strength (handgrip force), lower extremity muscle endurance (sit-to-stand test), flexibility (sit-and-reach test), and cardiorespiratory endurance (2-minute step test). Multivariable logistic regression and correlation analysis were performed to determine the association of metabolic syndrome with body composition and functionality variables. Metabolic syndrome was associated with increased skeletal muscle index (SMI) (odds ratio (OR), 1.61, 95% confidence interval (CI), 1.25-2.07) and decreased flexibility (OR, 0.97, 95% CI, 0.95-0.99) compared with those without metabolic syndrome. When body mass index was accounted for in the analysis, the association of SMI with metabolic syndrome was reduced. Waist circumference was positively correlated with SMI but negatively correlated with flexibility, whereas high density lipoprotein was positively correlated with flexibility but negatively correlated with SMI. Reduced flexibility was positively associated with metabolic syndrome independent of age, gender, body composition, and functionality measurements in a community based geriatric population. Significant associations between metabolic syndrome with muscle strength and cardiorespiratory fitness in the elderly were not observed. Furthermore, flexibility should be included in the complete evaluation for metabolic syndrome.

Health-Related Measures of Children's Physical Fitness.

ERIC Educational Resources Information Center

Pate, Russell R.

1991-01-01

Summarizes health-related physical fitness measurement procedures for children, emphasizing field measures. Health-related physical fitness encompasses cardiorespiratory endurance, body composition, muscular strength and endurance, and flexibility. The article presents several issues pertinent to research on health-related fitness testing. (SM)

[Physical fitness levels in French adolescents: The BOUGE program].

PubMed

Vanhelst, J; Béghin, L; Drumez, E; Baudelet, J-B; Labreuche, J; Chapelot, D; Mikulovic, J; Ulmer, Z

2016-09-01

A high level of physical fitness is associated with cardiovascular health in adolescents. The aims of this study were to assess the levels of physical fitness of French adolescents and to determine the prevalence of these adolescents below the minimum level of cardiorespiratory fitness needed to guarantee future favorable cardiovascular profile. Participants were 12,082 French children and adolescents (5975 boys, 6107 girls) aged to 9 from 16 years. Cardiorespiratory fitness, muscular endurance, speed, flexibility and speed agility were tested. The associations of physical fitness measures with adolescent's characteristics were analyzed using Student t test, one-way ANOVA, or Pearson correlations as appropriate. Boys were physically fitter than girls, expected for flexibility (P<0.0001). Subjects of normal weight adolescents had significantly better results than overweight or obese adolescents (P<0.05 for all comparisons), but also in comparison with underweight adolescents for muscular endurance, flexibility, cardiorespiratory fitness test (P<0.05). Our findings indicate that, on the basis of cardiorespiratory fitness, 16% of French boys and 7.7% of French girls have a risk of future cardiovascular disease (P<0.0001). This subgroup also performed poorly in all other tests of physical fitness used (P<0.0001). Aerobic fitness decreased significantly with the age (r=-0.168 for boys; r=-0.261 for girls). Our results indicate that the physical fitness of French adolescents must be improved to help protect against cardiovascular disease in adulthood, especially in boys. The study showed also a dramatically decrease of the cardiorespiratory fitness during the adolescence period. Developing and introducing a health promotion curriculum in the French schools is suggested to improve health and physical fitness. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Statistically generated weighted curve fit of residual functions for modal analysis of structures

NASA Technical Reports Server (NTRS)

Bookout, P. S.

1995-01-01

A statistically generated weighting function for a second-order polynomial curve fit of residual functions has been developed. The residual flexibility test method, from which a residual function is generated, is a procedure for modal testing large structures in an external constraint-free environment to measure the effects of higher order modes and interface stiffness. This test method is applicable to structures with distinct degree-of-freedom interfaces to other system components. A theoretical residual function in the displacement/force domain has the characteristics of a relatively flat line in the lower frequencies and a slight upward curvature in the higher frequency range. In the test residual function, the above-mentioned characteristics can be seen in the data, but due to the present limitations in the modal parameter evaluation (natural frequencies and mode shapes) of test data, the residual function has regions of ragged data. A second order polynomial curve fit is required to obtain the residual flexibility term. A weighting function of the data is generated by examining the variances between neighboring data points. From a weighted second-order polynomial curve fit, an accurate residual flexibility value can be obtained. The residual flexibility value and free-free modes from testing are used to improve a mathematical model of the structure. The residual flexibility modal test method is applied to a straight beam with a trunnion appendage and a space shuttle payload pallet simulator.

Fitness Basics

MedlinePlus

... and some great stretches to keep your body flexible. And in other girlshealth.gov Fitness sections you can make a plan for your routine, learn what to wear to work out , and find out about food and fitness . ...

The role of physical fitness as risk indicator of increased low back pain intensity among people working with physically and mentally disabled persons: a 30-month prospective study.

PubMed

Strøyer, Jesper; Jensen, Lone Donbaek

2008-03-01

A prospective cohort study. To study if low level of physical fitness was associated with increased low back pain (LBP) intensity at 30-month follow-up. The evidence of low physical fitness as a risk factor for LBP is inconclusive due to contradictory results. Study participants were 327 employees (women = 271, men = 56) at institutions for physically and mentally disabled persons. Physical fitness was measured by tests of: back extension and flexion endurance, flexibility and balance; and by self-assessed aerobic fitness, muscle strength, endurance, flexibility and balance, using visual analogue scales. Low back pain, lifestyle parameters, and physical and psychosocial work factors were assessed by questionnaires at baseline and at follow-up. Outcome was defined as an increase above 2 steps in average LBP intensity during the previous year (0-10). Persons with low level back endurance showed an insignificantly higher risk of increased LBP intensity (OR = 2.4, P = 0.076), whereas persons with medium level back endurance were at significantly higher risk (OR = 2.7, P = 0.034) compared with those with high level back endurance. The general association between isometric back extension endurance and increased LBP intensity was insignificant (P = 0.067). Persons with medium level self-assessed aerobic fitness were at lower risk of increased LBP intensity compared with those with high level (OR = 0.37, P = 0.02), although the general association of aerobic fitness was insignificant (0.066). Performance-based back flexion endurance, flexibility, and balance; and self-assessed muscle strength, endurance, flexibility, and balance were not associated with increased LBP intensity. The significant association between medium level back extension endurance and increased LBP intensity supports the finding of other studies that particularly back extension endurance is an important physical fitness component in preventing LBP and that the subcomponents of physical fitness are related in different ways to LBP.

Fitness change and subsequent academic performance in adolescents.

PubMed

Chen, Li-Jung; Fox, Kenneth R; Ku, Po-Wen; Taun, Chih-Yang

2013-09-01

This study examined the association between fitness change and subsequent academic performance in Taiwanese schoolchildren from 7th grade to 9th grade. The 7th graders from 1 junior high school district participated in this study (N = 669). Academic performance was extracted from school records at the end of each grade. Cardiovascular (CV) fitness, sit-and-reach flexibility, bent-leg curl-ups, and height and weight for calculating body mass index (BMI) were assessed at the start of each grade. The results showed that improvement in CV fitness, but not muscular endurance or flexibility, is significantly related to greater academic performance. A weak and nonsignificant academic-BMI relationship was seen. CV fitness exhibits stronger longitudinal associations with academic performance than other forms of fitness or BMI for adolescents. © 2013, American School Health Association.

A Flexible Domain-Domain Hinge Promotes an Induced-fit Dominant Mechanism for the Loading of Guide-DNA into Argonaute Protein in Thermus thermophilus.

PubMed

Zhu, Lizhe; Jiang, Hanlun; Sheong, Fu Kit; Cui, Xuefeng; Gao, Xin; Wang, Yanli; Huang, Xuhui

2016-03-17

Argonaute proteins (Ago) are core components of the RNA Induced Silencing Complex (RISC) that load and utilize small guide nucleic acids to silence mRNAs or cleave foreign DNAs. Despite the essential role of Ago in gene regulation and defense against virus, the molecular mechanism of guide-strand loading into Ago remains unclear. We explore such a mechanism in the bacterium Thermus thermophilus Ago (TtAgo), via a computational approach combining molecular dynamics, bias-exchange metadynamics, and protein-DNA docking. We show that apo TtAgo adopts multiple closed states that are unable to accommodate guide-DNA. Conformations able to accommodate the guide are beyond the reach of thermal fluctuations from the closed states. These results suggest an induced-fit dominant mechanism for guide-strand loading in TtAgo, drastically different from the two-step mechanism for human Ago 2 (hAgo2) identified in our previous study. Such a difference between TtAgo and hAgo2 is found to mainly originate from the distinct rigidity of their L1-PAZ hinge. Further comparison among known Ago structures from various species indicates that the L1-PAZ hinge may be flexible in general for prokaryotic Ago's but rigid for eukaryotic Ago's.

Dynamical modeling and multi-experiment fitting with PottersWheel

PubMed Central

Maiwald, Thomas; Timmer, Jens

2008-01-01

Motivation: Modelers in Systems Biology need a flexible framework that allows them to easily create new dynamic models, investigate their properties and fit several experimental datasets simultaneously. Multi-experiment-fitting is a powerful approach to estimate parameter values, to check the validity of a given model, and to discriminate competing model hypotheses. It requires high-performance integration of ordinary differential equations and robust optimization. Results: We here present the comprehensive modeling framework Potters-Wheel (PW) including novel functionalities to satisfy these requirements with strong emphasis on the inverse problem, i.e. data-based modeling of partially observed and noisy systems like signal transduction pathways and metabolic networks. PW is designed as a MATLAB toolbox and includes numerous user interfaces. Deterministic and stochastic optimization routines are combined by fitting in logarithmic parameter space allowing for robust parameter calibration. Model investigation includes statistical tests for model-data-compliance, model discrimination, identifiability analysis and calculation of Hessian- and Monte-Carlo-based parameter confidence limits. A rich application programming interface is available for customization within own MATLAB code. Within an extensive performance analysis, we identified and significantly improved an integrator–optimizer pair which decreases the fitting duration for a realistic benchmark model by a factor over 3000 compared to MATLAB with optimization toolbox. Availability: PottersWheel is freely available for academic usage at http://www.PottersWheel.de/. The website contains a detailed documentation and introductory videos. The program has been intensively used since 2005 on Windows, Linux and Macintosh computers and does not require special MATLAB toolboxes. Contact: maiwald@fdm.uni-freiburg.de Supplementary information: Supplementary data are available at Bioinformatics online. PMID:18614583

Impact of the variation in dynamic vehicle load on flexible pavement responses

NASA Astrophysics Data System (ADS)

Ahsanuzzaman, Md

The purpose of this research was to evaluate the dynamic variation in asphalt pavement critical responses due to dynamic tire load variations. An attempt was also made to develop generalized regression equations to predict the dynamic response variation in flexible pavement under various dynamic load conditions. The study used an extensive database of computed pavement response histories for five different types of sites (smooth, rough, medium rough, very rough and severely rough), two different asphalt pavement structures (thin and thick) at two temperatures (70 °F and 104 °F), subjected to a tandem axle dual tire at three speeds 25, 37 and 50 mph (40, 60 and 80 km/h). All pavement responses were determined using the 3D-Move Analysis program (Version 1.2) developed by University of Nevada, Reno. A new term called Dynamic Response Coefficient (DRC) was introduced in this study to address the variation in critical pavement responses due to dynamic loads as traditionally measured by the Dynamic Load Coefficient (DLC). While DLC represents the additional varying component of the tire load, DRC represents the additional varying component of the response value (standard deviation divided by mean response). In this study, DRC was compared with DLC for five different sites based on the roughness condition of the sites. Previous studies showed that DLC varies with vehicle speed and suspension types, and assumes a constant value for the whole pavement structure (lateral and vertical directions). On the other hand, in this study, DRC was found to be significantly varied with the asphalt pavement and function of pavement structure, road roughness conditions, temperatures, vehicle speeds, suspension types, and locations of the point of interest in the pavement. A major contribution of the study is that the variation of pavement responses due to dynamic load in a flexible pavement system can be predicted with generalized regression equations. Fitting parameters (R2) in the rage of 0.60 to 0.87 were observed the DRC predictive equations. In addition, verification of those generalized equations was evaluated using different sets of asphalt pavement structures and pavement materials. The differences between calculated and predicted values were found to be within +/-20% for the maximum tensile strain and +/-30% for the maximum compressive strain in the asphalt layer.

Fitness: A Family Affair. Spotlight: Physical Development.

ERIC Educational Resources Information Center

Turner, Joy

2000-01-01

Discusses ways parents can help children create a lifestyle that supports physical fitness, focusing on motivation for children and parents. Defines the components of fitness: cardiorespiratory endurance, muscular strength, muscular endurance, and flexibility. Presents information on developing adult and child fitness programs, including a workout…

TEMPy: a Python library for assessment of three-dimensional electron microscopy density fits.

PubMed

Farabella, Irene; Vasishtan, Daven; Joseph, Agnel Praveen; Pandurangan, Arun Prasad; Sahota, Harpal; Topf, Maya

2015-08-01

Three-dimensional electron microscopy is currently one of the most promising techniques used to study macromolecular assemblies. Rigid and flexible fitting of atomic models into density maps is often essential to gain further insights into the assemblies they represent. Currently, tools that facilitate the assessment of fitted atomic models and maps are needed. TEMPy (template and electron microscopy comparison using Python) is a toolkit designed for this purpose. The library includes a set of methods to assess density fits in intermediate-to-low resolution maps, both globally and locally. It also provides procedures for single-fit assessment, ensemble generation of fits, clustering, and multiple and consensus scoring, as well as plots and output files for visualization purposes to help the user in analysing rigid and flexible fits. The modular nature of TEMPy helps the integration of scoring and assessment of fits into large pipelines, making it a tool suitable for both novice and expert structural biologists.

Influence of Structural Flexibility on the Dynamic Precision of a Vehicle-Mounted Equipment System

DTIC Science & Technology

2015-05-12

Paramsothy Jayakumar , Dave Mechergui, Ronald Renke U.S.Army RDECOM TARDEC INFLUENCE OF STRUCTURAL FLEXIBILITY ON THE DYNAMIC PRECISION OF A...COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE INFLUENCE OF STRUCTURAL FLEXIBILITY ON THE DYNAMIC PRECISION OF A VEHICLE-MOUNTED EQUIPMENT...Equipment Enclosure CMS Results 23 12. Influence of CMS Method on the Vehicle Dynamics 24 13. Influence of Flexibility on the Vehicle

Effect of Ramadan intermittent fasting on selective fitness profile parameters in young untrained Muslim men.

PubMed

Roy, Anindita Singha; Bandyopadhyay, Amit

2015-01-01

The present study was aimed at investigating the effects of sleep deprivation and dietary irregularities during Ramadan intermittent fasting (RIF) on selective fitness profile parameters in young untrained male Muslim individuals. 77 untrained Muslim men were recruited in the study. They were divided into the experimental group (EG; n=37, age: 22.62±1.77 years) and the control group (CG; n=40, age: 23.00±1.48 years). EG was undergoing RIF while CG abstained. Aerobic fitness, anaerobic capacity or high-intensity efforts (HIEs), agility, flexibility, vertical jump height and handgrip strength were measured on 8 separate occasions-15 days before RIF, 7 days before RIF, 1st day of RIF, 7th day of RIF, 15th day of RIF, 21st day of RIF, last day of RIF and 15 days after RIF. Aerobic fitness and HIE showed a significant difference (p<0.05) during RIF in EG. Agility and flexibility score showed a significant decrease in EG during RIF, whereas changes in the vertical jump score (VJT) and handgrip strength were statistically insignificant. Studied parameters showed an insignificant variation in CG during RIF. Aerobic fitness, HIEs, agility and flexibility showed a significant intergroup variation during different experimental trials. The present investigation revealed that RIF had adverse effects on aerobic fitness, HIEs, agility and flexibility of young untrained Muslims of Kolkata, India. VJT, waist-hip ratio and handgrip strength were not affected by RIF in the studied population. Mild but statistically insignificant reduction in body mass was also reflected after the mid-Ramadan week.

RELIABLE RADIOGRAPHIC INSPECTION OF FLEXIBLE RISERS FOR THE OIL INDUSTRY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Almeida, Romulo M.; Rebello, Joao Marcos A.; Vaz, Murilo A.

2010-02-22

Flexible risers are composite tubular structures manufactured by the concentric assemblage of cylindrical polymeric and helically wound metallic layers employed to convey pressurized fluids such as oil, gas and water in the ocean environment. The metallic layers account for the flexible risers' structural strength and are dimensioned according to the static and dynamic loads. They are usually installed in a free hanging catenary configuration and are subjected to the direct action of waves and marine currents and wave induced motions from the oil production platform. The fatigue rupture of wire armours in the end fitting or within the riser segmentmore » protected by the bend stiffener is an object of major concern. Integrity models have been developed, however inspection techniques are mandatory to ensure that failure is detected. Gammagraphy has been used as a common inspection technique in all regions of the flexible riser, mainly with the single wall-single view method. On the other side, there is not any qualified radiographic procedure to this kind of structure. Radiographic simulation was adopted and its validation with actual gammagraphies and establishment of radiographic parameters to complex radiation geometries were done. Results show the viability of the radiographic inspection analyzing the armour wires' rupture and the displacement between wires.« less

Reliable Radiographic Inspection of Flexible Risers for the Oil Industry

NASA Astrophysics Data System (ADS)

Almeida, Rômulo M.; Rebello, Joao Marcos A.; Vaz, Murilo A.

2010-02-01

Flexible risers are composite tubular structures manufactured by the concentric assemblage of cylindrical polymeric and helically wound metallic layers employed to convey pressurized fluids such as oil, gas and water in the ocean environment. The metallic layers account for the flexible risers' structural strength and are dimensioned according to the static and dynamic loads. They are usually installed in a free hanging catenary configuration and are subjected to the direct action of waves and marine currents and wave induced motions from the oil production platform. The fatigue rupture of wire armours in the end fitting or within the riser segment protected by the bend stiffener is an object of major concern. Integrity models have been developed, however inspection techniques are mandatory to ensure that failure is detected. Gammagraphy has been used as a common inspection technique in all regions of the flexible riser, mainly with the single wall-single view method. On the other side, there is not any qualified radiographic procedure to this kind of structure. Radiographic simulation was adopted and its validation with actual gammagraphies and establishment of radiographic parameters to complex radiation geometries were done. Results show the viability of the radiographic inspection analyzing the armour wires' rupture and the displacement between wires.

Grant programs : design features shape flexibility, accountability, and performance information

DOT National Transportation Integrated Search

1998-06-01

Flexible grants--block grants and similar programs that give state or local governments the flexibility to adapt funded activities to fit the state or local context--are an adaptable policy tool and are found in fields from urban transit to community...

Dynamic analysis and control of lightweight manipulators with flexible parallel link mechanisms

NASA Technical Reports Server (NTRS)

Lee, Jeh Won

1991-01-01

The flexible parallel link mechanism is designed for increased rigidity to sustain the buckling when it carries a heavy payload. Compared to a one link flexible manipulator, a two link flexible manipulator, especially the flexible parallel mechanism, has more complicated characteristics in dynamics and control. The objective of this research is the theoretical analysis and the experimental verification of dynamics and control of a two link flexible manipulator with a flexible parallel link mechanism. Nonlinear equations of motion of the lightweight manipulator are derived by the Lagrangian method in symbolic form to better understand the structure of the dynamic model. A manipulator with a flexible parallel link mechanism is a constrained dynamic system whose equations are sensitive to numerical integration error. This constrained system is solved using singular value decomposition of the constraint Jacobian matrix. The discrepancies between the analytical model and the experiment are explained using a simplified and a detailed finite element model. The step response of the analytical model and the TREETOPS model match each other well. The nonlinear dynamics is studied using a sinusoidal excitation. The actuator dynamic effect on a flexible robot was investigated. The effects are explained by the root loci and the Bode plot theoretically and experimentally. For the base performance for the advanced control scheme, a simple decoupled feedback scheme is applied.

Fitness characteristics of a suburban special weapons and tactics team.

PubMed

Pryor, Riana R; Colburn, Deanna; Crill, Matthew T; Hostler, David P; Suyama, J

2012-03-01

Special Weapons and Tactics (SWAT) operators are specialized law enforcement officers who traditionally perform their duties with higher anticipated workloads because of additional body armor, weapons, and equipment used for enhanced operations and protection. This elevated workload increases the need for SWAT operators to improve or maintain their physical fitness to consistently perform routine operations. Typical tasks require trunk rotation, overhead upper extremity use, upper and lower body strength use, and long waiting periods followed by explosive movements while wearing additional equipment. Eleven male SWAT operators from 1 SWAT team performed flexibility, strength, power, and aerobic capacity tests and a variety of job-related tasks. Data were compared with age- and gender-based normative data. Fitness testing revealed that officers ranked high on tests of muscular strength (leg strength, 90th percentile; bench press, 85th percentile); however, body composition (55th percentile), core body strength, and flexibility ranked lower. Furthermore, aerobic capacity and muscular power had a wide range of scores and were also not ideal to support maximal performance during routine operations. These data can assist exercise specialists choose fitness programs specifically for job-related tasks of SWAT operators when creating fitness programs. Fitness programming for law enforcement should focus on improving aerobic fitness, flexibility, core strength, and muscular power while maintaining muscular strength to meet the needs of these specialized officers.

The intrinsic flexibility of the aptamer targeting the ribosomal protein S8 is a key factor for the molecular recognition.

PubMed

Autiero, Ida; Ruvo, Menotti; Improta, Roberto; Vitagliano, Luigi

2018-04-01

Aptamers are RNA/DNA biomolecules representing an emerging class of protein interactors and regulators. Despite the growing interest in these molecules, current understanding of chemical-physical basis of their target recognition is limited. Recently, the characterization of the aptamer targeting the protein-S8 has suggested that flexibility plays important functional roles. We investigated the structural versatility of the S8-aptamer by molecular dynamics simulations. Five different simulations have been conducted by varying starting structures and temperatures. The simulation of S8-aptamer complex provides a dynamic view of the contacts occurring at the complex interface. The simulation of the aptamer in ligand-free state indicates that its central region is intrinsically endowed with a remarkable flexibility. Nevertheless, none of the trajectory structures adopts the structure observed in the S8-aptamer complex. The aptamer ligand-bound is very rigid in the simulation carried out at 300 K. A structural transition of this state, providing insights into the aptamer-protein recognition process, is observed in a simulation carried out at 400 K. These data indicate that a key event in the binding is linked to the widening of the central region of the aptamer. Particularly relevant is switch of the A26 base from its ligand-free state to a location that allows the G13-C28 base-pairing. Intrinsic flexibility of the aptamer is essential for partner recognition. Present data indicate that S8 recognizes the aptamer through an induced-fit rather than a population-shift mechanism. The present study provides deeper understanding of the structural basis of the structural versatility of aptamers. Copyright © 2018 Elsevier B.V. All rights reserved.

An Evaluation of Explicit Receptor Flexibility in Molecular Docking Using Molecular Dynamics and Torsion Angle Molecular Dynamics.

PubMed

Armen, Roger S; Chen, Jianhan; Brooks, Charles L

2009-10-13

Incorporating receptor flexibility into molecular docking should improve results for flexible proteins. However, the incorporation of explicit all-atom flexibility with molecular dynamics for the entire protein chain may also introduce significant error and "noise" that could decrease docking accuracy and deteriorate the ability of a scoring function to rank native-like poses. We address this apparent paradox by comparing the success of several flexible receptor models in cross-docking and multiple receptor ensemble docking for p38α mitogen-activated protein (MAP) kinase. Explicit all-atom receptor flexibility has been incorporated into a CHARMM-based molecular docking method (CDOCKER) using both molecular dynamics (MD) and torsion angle molecular dynamics (TAMD) for the refinement of predicted protein-ligand binding geometries. These flexible receptor models have been evaluated, and the accuracy and efficiency of TAMD sampling is directly compared to MD sampling. Several flexible receptor models are compared, encompassing flexible side chains, flexible loops, multiple flexible backbone segments, and treatment of the entire chain as flexible. We find that although including side chain and some backbone flexibility is required for improved docking accuracy as expected, docking accuracy also diminishes as additional and unnecessary receptor flexibility is included into the conformational search space. Ensemble docking results demonstrate that including protein flexibility leads to to improved agreement with binding data for 227 active compounds. This comparison also demonstrates that a flexible receptor model enriches high affinity compound identification without significantly increasing the number of false positives from low affinity compounds.

An Evaluation of Explicit Receptor Flexibility in Molecular Docking Using Molecular Dynamics and Torsion Angle Molecular Dynamics

PubMed Central

Armen, Roger S.; Chen, Jianhan; Brooks, Charles L.

2009-01-01

Incorporating receptor flexibility into molecular docking should improve results for flexible proteins. However, the incorporation of explicit all-atom flexibility with molecular dynamics for the entire protein chain may also introduce significant error and “noise” that could decrease docking accuracy and deteriorate the ability of a scoring function to rank native-like poses. We address this apparent paradox by comparing the success of several flexible receptor models in cross-docking and multiple receptor ensemble docking for p38α mitogen-activated protein (MAP) kinase. Explicit all-atom receptor flexibility has been incorporated into a CHARMM-based molecular docking method (CDOCKER) using both molecular dynamics (MD) and torsion angle molecular dynamics (TAMD) for the refinement of predicted protein-ligand binding geometries. These flexible receptor models have been evaluated, and the accuracy and efficiency of TAMD sampling is directly compared to MD sampling. Several flexible receptor models are compared, encompassing flexible side chains, flexible loops, multiple flexible backbone segments, and treatment of the entire chain as flexible. We find that although including side chain and some backbone flexibility is required for improved docking accuracy as expected, docking accuracy also diminishes as additional and unnecessary receptor flexibility is included into the conformational search space. Ensemble docking results demonstrate that including protein flexibility leads to to improved agreement with binding data for 227 active compounds. This comparison also demonstrates that a flexible receptor model enriches high affinity compound identification without significantly increasing the number of false positives from low affinity compounds. PMID:20160879

Origin of higher affinity to RNA of the N-terminal RNA-binding domain than that of the C-terminal one of a mouse neural protein, musashi1, as revealed by comparison of their structures, modes of interaction, surface electrostatic potentials, and backbone dynamics.

PubMed

Miyanoiri, Youhei; Kobayashi, Hisanori; Imai, Takao; Watanabe, Michinao; Nagata, Takashi; Uesugi, Seiichi; Okano, Hideyuki; Katahira, Masato

2003-10-17

Musashi1 is an RNA-binding protein abundantly expressed in the developing mouse central nervous system. Its restricted expression in neural precursor cells suggests that it is involved in maintenance of the character of progenitor cells. Musashi1 contains two ribonucleoprotein-type RNA-binding domains (RBDs), RBD1 and RBD2, the affinity to RNA of RBD1 being much higher than that of RBD2. We previously reported the structure and mode of interaction with RNA of RBD2. Here, we have determined the structure and mode of interaction with RNA of RBD1. We have also analyzed the surface electrostatic potential and backbone dynamics of both RBDs. The two RBDs exhibit the same ribo-nucleoprotein-type fold and commonly make contact with RNA on the beta-sheet side. On the other hand, there is a remarkable difference in surface electrostatic potential, the beta-sheet of RBD1 being positively charged, which is favorable for binding negatively charged RNA, but that of RBD2 being almost neutral. There is also a difference in backbone dynamics, the central portion of the beta-sheet of RBD1 being flexible, but that of RBD2 not being flexible. The flexibility of RBD1 may be utilized in the recognition process to facilitate an induced fit. Thus, comparative studies have revealed the origin of the higher affinity of RBD1 than that of RBD2 and indicated that the affinity of an RBD to RNA is not governed by its fold alone but is also determined by its surface electrostatic potential and/or backbone dynamics. The biological role of RBD2 with lower affinity is also discussed.

Rigid-flexible coupling dynamic modeling and investigation of a redundantly actuated parallel manipulator with multiple actuation modes

NASA Astrophysics Data System (ADS)

Liang, Dong; Song, Yimin; Sun, Tao; Jin, Xueying

2017-09-01

A systematic dynamic modeling methodology is presented to develop the rigid-flexible coupling dynamic model (RFDM) of an emerging flexible parallel manipulator with multiple actuation modes. By virtue of assumed mode method, the general dynamic model of an arbitrary flexible body with any number of lumped parameters is derived in an explicit closed form, which possesses the modular characteristic. Then the completely dynamic model of system is formulated based on the flexible multi-body dynamics (FMD) theory and the augmented Lagrangian multipliers method. An approach of combining the Udwadia-Kalaba formulation with the hybrid TR-BDF2 numerical algorithm is proposed to address the nonlinear RFDM. Two simulation cases are performed to investigate the dynamic performance of the manipulator with different actuation modes. The results indicate that the redundant actuation modes can effectively attenuate vibration and guarantee higher dynamic performance compared to the traditional non-redundant actuation modes. Finally, a virtual prototype model is developed to demonstrate the validity of the presented RFDM. The systematic methodology proposed in this study can be conveniently extended for the dynamic modeling and controller design of other planar flexible parallel manipulators, especially the emerging ones with multiple actuation modes.

On the Trail to Fitness.

ERIC Educational Resources Information Center

American School and University, 1979

1979-01-01

The University of Hartford planned fitness trail will allow students to develop their bodies by providing a jogging route to improve cardiovascular fitness and exercise stations designed to provide warm-up exercises and improve strength, flexibility, balance, and endurance. (Author/MLF)

Decreased health-related physical fitness in adults with ankylosing spondylitis: a cross-sectional controlled study.

PubMed

O'Dwyer, Tom; O'Shea, Finbar; Wilson, Fiona

2016-06-01

(1) Assess the health-related physical fitness of adults with ankylosing spondylitis (AS) and compare these to the general population, and (2) examine the relationships between physical fitness and condition-specific outcomes. Cross-sectional, controlled study. Exercise research laboratory. Thirty-nine adults with AS (32 men, 7 women) and 39 age- and gender-matched controls. Comprehensive physical fitness assessment, and completion of questionnaires assessing disease activity, physical function and quality-of-life. Body composition was assessed by bio-impedance analysis. Flexibility was measured with the Bath AS Metrology Index (BASMI). Cardiorespiratory fitness was assessed by submaximal treadmill test with breath-by-breath gas analysis and heart rate monitoring. Muscular strength and endurance were measured by isokinetic dynamometry of concentric knee flexion/extension. The AS group demonstrated significantly lower cardiorespiratory fitness [mean difference -1.3mLmin(-1)kg(-1) (95% CI -1.1 to -1.4)], flexibility [0.4 BASMI units (0.2 to 0.7)], muscular strength [-31.6 peak torque per body weight dominant knee extension (-56.1 to -7.1)], and increased body fat [0.4% (0.0 to 1.2)] compared to population controls (p<.05). There were significant associations between each fitness component and physical function (p<.05). Higher aerobic capacity was significantly associated with improved quality-of-life. Fitness was not significantly associated with disease activity. Adults with AS have significantly reduced health-related physical fitness compared to population controls. Decreased body fat, and higher aerobic capacity, muscular fitness and flexibility are significantly associated with improved function. These findings have implications for clinicians assessing adults with AS, and for targeted-exercise prescription in this cohort. Copyright © 2015 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

Physical fitness reference standards in European children: the IDEFICS study.

PubMed

De Miguel-Etayo, P; Gracia-Marco, L; Ortega, F B; Intemann, T; Foraita, R; Lissner, L; Oja, L; Barba, G; Michels, N; Tornaritis, M; Molnár, D; Pitsiladis, Y; Ahrens, W; Moreno, L A

2014-09-01

A low fitness status during childhood and adolescence is associated with important health-related outcomes, such as increased future risk for obesity and cardiovascular diseases, impaired skeletal health, reduced quality of life and poor mental health. Fitness reference values for adolescents from different countries have been published, but there is a scarcity of reference values for pre-pubertal children in Europe, using harmonised measures of fitness in the literature. The IDEFICS study offers a good opportunity to establish normative values of a large set of fitness components from eight European countries using common and well-standardised methods in a large sample of children. Therefore, the aim of this study is to report sex- and age-specific fitness reference standards in European children. Children (10,302) aged 6-10.9 years (50.7% girls) were examined. The test battery included: the flamingo balance test, back-saver sit-and-reach test (flexibility), handgrip strength test, standing long jump test (lower-limb explosive strength) and 40-m sprint test (speed). Moreover, cardiorespiratory fitness was assessed by a 20-m shuttle run test. Percentile curves for the 1st, 3rd, 10th, 25th, 50th, 75th, 90th, 97th and 99th percentiles were calculated using the General Additive Model for Location Scale and Shape (GAMLSS). Our results show that boys performed better than girls in speed, lower- and upper-limb strength and cardiorespiratory fitness, and girls performed better in balance and flexibility. Older children performed better than younger children, except for cardiorespiratory fitness in boys and flexibility in girls. Our results provide for the first time sex- and age-specific physical fitness reference standards in European children aged 6-10.9 years.

Reduced Flexibility Associated with Metabolic Syndrome in Community-Dwelling Elders

PubMed Central

Chang, Ke-Vin; Hung, Chen-Yu; Li, Chia-Ming; Lin, Yu-Hung; Wang, Tyng-Guey; Tsai, Keh-Sung; Han, Der-Sheng

2015-01-01

Background The ageing process may lead to reductions in physical fitness, a known risk factor in the development of metabolic syndrome. The purpose of the current study was to evaluate cross-sectional and combined associations of metabolic syndrome with body composition and physical fitness in a community based geriatric population. Methods A total of 628 community-dwelling elders attending a geriatric health examination were enrolled in the study. The diagnosis of metabolic syndrome was based on the modified National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criterion with Asian cutoff of waist girth was adopted in this study. Body composition was obtained using bioimpedance analysis, and physical fitness was evaluated through the measurement of muscle strength (handgrip force), lower extremity muscle endurance (sit-to-stand test), flexibility (sit-and-reach test), and cardiorespiratory endurance (2-minute step test). Multivariable logistic regression and correlation analysis were performed to determine the association of metabolic syndrome with body composition and functionality variables. Results Metabolic syndrome was associated with increased skeletal muscle index (SMI) (odds ratio (OR), 1.61, 95% confidence interval (CI), 1.25–2.07) and decreased flexibility (OR, 0.97, 95% CI, 0.95–0.99) compared with those without metabolic syndrome. When body mass index was accounted for in the analysis, the association of SMI with metabolic syndrome was reduced. Waist circumference was positively correlated with SMI but negatively correlated with flexibility, whereas high density lipoprotein was positively correlated with flexibility but negatively correlated with SMI. Conclusion Reduced flexibility was positively associated with metabolic syndrome independent of age, gender, body composition, and functionality measurements in a community based geriatric population. Significant associations between metabolic syndrome with muscle strength and cardiorespiratory fitness in the elderly were not observed. Furthermore, flexibility should be included in the complete evaluation for metabolic syndrome. PMID:25614984

Control of a flexible bracing manipulator: Integration of current research work to realize the bracing manipulator

NASA Technical Reports Server (NTRS)

Kwon, Dong-Soo

1991-01-01

All research results about flexible manipulator control were integrated to show a control scenario of a bracing manipulator. First, dynamic analysis of a flexible manipulator was done for modeling. Second, from the dynamic model, the inverse dynamic equation was derived, and the time domain inverse dynamic method was proposed for the calculation of the feedforward torque and the desired flexible coordinate trajectories. Third, a tracking controller was designed by combining the inverse dynamic feedforward control with the joint feedback control. The control scheme was applied to the tip position control of a single link flexible manipulator for zero and non-zero initial condition cases. Finally, the contact control scheme was added to the position tracking control. A control scenario of a bracing manipulator is provided and evaluated through simulation and experiment on a single link flexible manipulator.

Impact of a community-based exercise programme on physical fitness in middle-aged and older patients with type 2 diabetes.

PubMed

Mendes, Romeu; Sousa, Nelson; Themudo-Barata, José; Reis, Victor

2016-01-01

Physical fitness is related to all-cause mortality, quality of life and risk of falls in patients with type 2 diabetes. This study aimed to analyse the impact of a long-term community-based combined exercise program (aerobic+resistance+agility/balance+flexibility) developed with minimum and low-cost material resources on physical fitness in middle-aged and older patients with type 2 diabetes. This was a non-experimental pre-post evaluation study. Participants (N=43; 62.92±5.92 years old) were engaged in a community-based supervised exercise programme (consisting of combined aerobic, resistance, agility/balance and flexibility exercises; three sessions per week; 70min per session) of 9 months' duration. Aerobic fitness (6-Minute Walk Test), muscle strength (30-Second Chair Stand Test), agility/balance (Timed Up and Go Test) and flexibility (Chair Sit and Reach Test) were assessed before (baseline) and after the exercise intervention. Significant improvements in the performance of the 6-Minute Walk Test (Δ=8.20%, p<0.001), 30-Second Chair Stand Test (Δ=28.84%, p<0.001), Timed Up and Go Test (Δ=14.31%, p<0.001), and Chair Sit and Reach Test (Δ=102.90%, p<0.001) were identified between baseline and end-exercise intervention time points. A long-term community-based combined exercise programme, developed with low-cost exercise strategies, produced significant benefits in physical fitness in middle-aged and older patients with type 2 diabetes. This supervised group exercise programme significantly improved aerobic fitness, muscle strength, agility/balance and flexibility, assessed with field tests in community settings. Copyright © 2016 SESPAS. Published by Elsevier Espana. All rights reserved.

The Relationship of the Sit and Reach Test to Criterion Measures of Hamstring and Back Flexibility in Young Females.

ERIC Educational Resources Information Center

Jackson, Allen W.; Baker, Alice A.

1986-01-01

This study tested 100 female adolescents to determine the relationships of the sit and reach test, a component of the Health Related Fitness Test, with back and hamstring flexibility. Findings indicate the sit and reach test is moderately related to hamstring flexibility but not to back and low back flexibility. (Author/MT)

Integration of car-body flexibility into train-track coupling system dynamics analysis

NASA Astrophysics Data System (ADS)

Ling, Liang; Zhang, Qing; Xiao, Xinbiao; Wen, Zefeng; Jin, Xuesong

2018-04-01

The resonance vibration of flexible car-bodies greatly affects the dynamics performances of high-speed trains. In this paper, we report a three-dimensional train-track model to capture the flexible vibration features of high-speed train carriages based on the flexible multi-body dynamics approach. The flexible car-body is modelled using both the finite element method (FEM) and the multi-body dynamics (MBD) approach, in which the rigid motions are obtained by using the MBD theory and the structure deformation is calculated by the FEM and the modal superposition method. The proposed model is applied to investigate the influence of the flexible vibration of car-bodies on the dynamics performances of train-track systems. The dynamics performances of a high-speed train running on a slab track, including the car-body vibration behaviour, the ride comfort, and the running safety, calculated by the numerical models with rigid and flexible car-bodies are compared in detail. The results show that the car-body flexibility not only significantly affects the vibration behaviour and ride comfort of rail carriages, but also can has an important influence on the running safety of trains. The rigid car-body model underestimates the vibration level and ride comfort of rail vehicles, and ignoring carriage torsional flexibility in the curving safety evaluation of trains is conservative.

Mental Fitness for Life: Assessing the Impact of an 8-Week Mental Fitness Program on Healthy Aging.

ERIC Educational Resources Information Center

Cusack, Sandra A.; Thompson, Wendy J. A.; Rogers, Mary E.

2003-01-01

A mental fitness program taught goal setting, critical thinking, creativity, positive attitudes, learning, memory, and self-expression to adults over 50 (n=22). Pre/posttests of depression and cognition revealed significant impacts on mental fitness, cognitive confidence, goal setting, optimism, creativity, flexibility, and memory. Not significant…

Physical fitness and associations with anthropometric measurements in 7 to 15-year-old school children.

PubMed

Andreasi, Viviane; Michelin, Edilaine; Rinaldi, Ana Elisa M; Burini, Roberto Carlos

2010-01-01

To analyze associations between health-related physical fitness and the anthropometric and demographic indicators of children at three elementary schools in Botucatu, SP, Brazil. The sample for this cross-sectional study was 988 elementary school students, recruited from the second to ninth grades (an age range of 7 to 15 years). The children underwent anthropometric assessment (weight, height, waist circumference and tricipital and subscapular skin folds) and were tested for health-related physical fitness (flexibility: sit and reach test; abdominal strength/stamina: 1-minute abdominal test; and aerobic stamina: 9-minute running/walking test). Data were analyzed using descriptive statistics plus Student's t test, the chi-square test or Fisher's exact test and logistic regression with a significance level of 5%. The physical fitness levels observed were significantly influenced by age (all levels), sex (abdominal strength/stamina), obesity (all levels), body adiposity (flexibility, abdominal strength/stamina) and abdominal adiposity (abdominal strength/stamina and aerobic stamina). Females were more prone to be unfit in abdominal strength/stamina. Both obesity and excessive abdominal adiposity predisposed children to be unfit in abdominal strength/stamina and aerobic stamina. Excess body adiposity increased the likelihood of poor trunk flexibility. Unhealthy physical fitness levels were related to female sex, obesity and excessive abdominal adiposity. Implementing programs designed to effect lifestyle changes to achieve physical fitness and healthy nutrition in these schools would meet the objectives of promoting healthy body weight and increased physical fitness among these schoolchildren.

Is it growing exponentially fast? -- Impact of assuming exponential growth for characterizing and forecasting epidemics with initial near-exponential growth dynamics.

PubMed

Chowell, Gerardo; Viboud, Cécile

2016-10-01

The increasing use of mathematical models for epidemic forecasting has highlighted the importance of designing models that capture the baseline transmission characteristics in order to generate reliable epidemic forecasts. Improved models for epidemic forecasting could be achieved by identifying signature features of epidemic growth, which could inform the design of models of disease spread and reveal important characteristics of the transmission process. In particular, it is often taken for granted that the early growth phase of different growth processes in nature follow early exponential growth dynamics. In the context of infectious disease spread, this assumption is often convenient to describe a transmission process with mass action kinetics using differential equations and generate analytic expressions and estimates of the reproduction number. In this article, we carry out a simulation study to illustrate the impact of incorrectly assuming an exponential-growth model to characterize the early phase (e.g., 3-5 disease generation intervals) of an infectious disease outbreak that follows near-exponential growth dynamics. Specifically, we assess the impact on: 1) goodness of fit, 2) bias on the growth parameter, and 3) the impact on short-term epidemic forecasts. Designing transmission models and statistical approaches that more flexibly capture the profile of epidemic growth could lead to enhanced model fit, improved estimates of key transmission parameters, and more realistic epidemic forecasts.

A decoupled recursive approach for constrained flexible multibody system dynamics

NASA Technical Reports Server (NTRS)

Lai, Hao-Jan; Kim, Sung-Soo; Haug, Edward J.; Bae, Dae-Sung

1989-01-01

A variational-vector calculus approach is employed to derive a recursive formulation for dynamic analysis of flexible multibody systems. Kinematic relationships for adjacent flexible bodies are derived in a companion paper, using a state vector notation that represents translational and rotational components simultaneously. Cartesian generalized coordinates are assigned for all body and joint reference frames, to explicitly formulate deformation kinematics under small deformation kinematics and an efficient flexible dynamics recursive algorithm is developed. Dynamic analysis of a closed loop robot is performed to illustrate efficiency of the algorithm.

Children's Television Viewing, Body Fat, and Physical Fitness.

ERIC Educational Resources Information Center

Armstrong, Colin A.; Sallis, James F.; Alcaraz, John E.; Kolody, Bohdan; McKenzie, Thomas L.; Hovell, Melbourne F.

1998-01-01

Examined the relationship between elementary students' television viewing and their physical fitness. Data from parent and student questionnaires and measures of body fat, cardiovascular fitness, muscular strength/endurance, and muscular flexibility indicated that television viewing weakly and inconsistently related to various components of…

Evaluation of I-FIT results and machine variability using MnRoad test track mixtures.

DOT National Transportation Integrated Search

2017-06-01

The Illinois Flexibility Index Test (I-FIT) was developed to distinguish between different mixtures in terms of potential cracking. Several : machines were manufactured and are currently available to perform the I-FIT. This report presents the result...

Flight Dynamics of Flexible Aircraft with Aeroelastic and Inertial Force Interactions

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.; Tuzcu, Ilhan

2009-01-01

This paper presents an integrated flight dynamic modeling method for flexible aircraft that captures coupled physics effects due to inertial forces, aeroelasticity, and propulsive forces that are normally present in flight. The present approach formulates the coupled flight dynamics using a structural dynamic modeling method that describes the elasticity of a flexible, twisted, swept wing using an equivalent beam-rod model. The structural dynamic model allows for three types of wing elastic motion: flapwise bending, chordwise bending, and torsion. Inertial force coupling with the wing elasticity is formulated to account for aircraft acceleration. The structural deflections create an effective aeroelastic angle of attack that affects the rigid-body motion of flexible aircraft. The aeroelastic effect contributes to aerodynamic damping forces that can influence aerodynamic stability. For wing-mounted engines, wing flexibility can cause the propulsive forces and moments to couple with the wing elastic motion. The integrated flight dynamics for a flexible aircraft are formulated by including generalized coordinate variables associated with the aeroelastic-propulsive forces and moments in the standard state-space form for six degree-of-freedom flight dynamics. A computational structural model for a generic transport aircraft has been created. The eigenvalue analysis is performed to compute aeroelastic frequencies and aerodynamic damping. The results will be used to construct an integrated flight dynamic model of a flexible generic transport aircraft.

The development and use of SPIO Lycra compression bracing in children with neuromotor deficits.

PubMed

Hylton, N; Allen, C

1997-01-01

The use of flexible compression bracing in persons with neuromotor deficits offers improved possibilities for stability and movement control without severely limiting joint movement options. At the Children's Therapy Center in Kent, Washington, this treatment modality has been explored with increasing application in children with moderate to severe cerebral palsy and other neuromotor deficits over the past 6 years, with good success. Significant functional improvements using Neoprene shoulder/trunk/hip Bracing led us to experiment with much lighter compression materials. The stabilizing pressure input orthosis or SPIO bracing system (developed by Cheryl Allen, parent and Chief Designer, and Nancy Hylton, PT) is custom-fitted to the stability, movement control and sensory deficit needs of a specific individual. SPIO bracing developed for a specific child has often become part of a rapidly increasing group of flexible bracing options which appear to provide an improved base of support for functional gains in balance, dynamic stability, general and specific movement control with improved postural and muscle readiness. Both deep sensory and subtle biomechanical factors may account for the functional changes observed. This article discusses the development and current use of flexible compression SPIO bracing in this area.

Spatial operator algebra for flexible multibody dynamics

NASA Technical Reports Server (NTRS)

Jain, A.; Rodriguez, G.

1993-01-01

This paper presents an approach to modeling the dynamics of flexible multibody systems such as flexible spacecraft and limber space robotic systems. A large number of degrees of freedom and complex dynamic interactions are typical in these systems. This paper uses spatial operators to develop efficient recursive algorithms for the dynamics of these systems. This approach very efficiently manages complexity by means of a hierarchy of mathematical operations.

Parametrization of Backbone Flexibility in a Coarse-Grained Force Field for Proteins (COFFDROP) Derived from All-Atom Explicit-Solvent Molecular Dynamics Simulations of All Possible Two-Residue Peptides.

PubMed

Frembgen-Kesner, Tamara; Andrews, Casey T; Li, Shuxiang; Ngo, Nguyet Anh; Shubert, Scott A; Jain, Aakash; Olayiwola, Oluwatoni J; Weishaar, Mitch R; Elcock, Adrian H

2015-05-12

Recently, we reported the parametrization of a set of coarse-grained (CG) nonbonded potential functions, derived from all-atom explicit-solvent molecular dynamics (MD) simulations of amino acid pairs and designed for use in (implicit-solvent) Brownian dynamics (BD) simulations of proteins; this force field was named COFFDROP (COarse-grained Force Field for Dynamic Representations Of Proteins). Here, we describe the extension of COFFDROP to include bonded backbone terms derived from fitting to results of explicit-solvent MD simulations of all possible two-residue peptides containing the 20 standard amino acids, with histidine modeled in both its protonated and neutral forms. The iterative Boltzmann inversion (IBI) method was used to optimize new CG potential functions for backbone-related terms by attempting to reproduce angle, dihedral, and distance probability distributions generated by the MD simulations. In a simple test of the transferability of the extended force field, the angle, dihedral, and distance probability distributions obtained from BD simulations of 56 three-residue peptides were compared to results from corresponding explicit-solvent MD simulations. In a more challenging test of the COFFDROP force field, it was used to simulate eight intrinsically disordered proteins and was shown to quite accurately reproduce the experimental hydrodynamic radii (Rhydro), provided that the favorable nonbonded interactions of the force field were uniformly scaled downward in magnitude. Overall, the results indicate that the COFFDROP force field is likely to find use in modeling the conformational behavior of intrinsically disordered proteins and multidomain proteins connected by flexible linkers.

Molecular dynamics-based refinement and validation for sub-5 Å cryo-electron microscopy maps.

PubMed

Singharoy, Abhishek; Teo, Ivan; McGreevy, Ryan; Stone, John E; Zhao, Jianhua; Schulten, Klaus

2016-07-07

Two structure determination methods, based on the molecular dynamics flexible fitting (MDFF) paradigm, are presented that resolve sub-5 Å cryo-electron microscopy (EM) maps with either single structures or ensembles of such structures. The methods, denoted cascade MDFF and resolution exchange MDFF, sequentially re-refine a search model against a series of maps of progressively higher resolutions, which ends with the original experimental resolution. Application of sequential re-refinement enables MDFF to achieve a radius of convergence of ~25 Å demonstrated with the accurate modeling of β-galactosidase and TRPV1 proteins at 3.2 Å and 3.4 Å resolution, respectively. The MDFF refinements uniquely offer map-model validation and B-factor determination criteria based on the inherent dynamics of the macromolecules studied, captured by means of local root mean square fluctuations. The MDFF tools described are available to researchers through an easy-to-use and cost-effective cloud computing resource on Amazon Web Services.

Fitness Profiles and Activity Patterns of Entering College Students.

ERIC Educational Resources Information Center

Pierce, Edgar F.; And Others

1992-01-01

Entering college students were evaluated for performance on maximal oxygen consumption, body composition, muscle endurance, muscle strength, and joint flexibility tests to determine the relationship of physical activity patterns to fitness levels. Results supported previous research indicating reduced fitness levels in young adults. (SM)

Flexible Force Field Parameterization through Fitting on the Ab Initio-Derived Elastic Tensor

PubMed Central

2017-01-01

Constructing functional forms and their corresponding force field parameters for the metal–linker interface of metal–organic frameworks is challenging. We propose fitting these parameters on the elastic tensor, computed from ab initio density functional theory calculations. The advantage of this top-down approach is that it becomes evident if functional forms are missing when components of the elastic tensor are off. As a proof-of-concept, a new flexible force field for MIL-47(V) is derived. Negative thermal expansion is observed and framework flexibility has a negligible effect on adsorption and transport properties for small guest molecules. We believe that this force field parametrization approach can serve as a useful tool for developing accurate flexible force field models that capture the correct mechanical behavior of the full periodic structure. PMID:28661672

Definition of the Flexible Image Transport System (FITS), Version 3.0

NASA Technical Reports Server (NTRS)

Pence, W. D.; Chiapetti, L.; Page, C. G.; Shaw, R. A.; Stobie, E.

2010-01-01

The Flexible Image Transport System (FITS) has been used by astronomers for over 30 years as a data interchange and archiving format; FITS files are now handled by a wide range of astronomical software packages. Since the FITS format definition document (the "standard") was last printed in this journal in 2001, several new features have been developed and standardized, notably support for 64-bit integers in images and tables, variable-length arrays in tables, and new world coordinate system conventions which provide a mapping from an element in a data array to a physical coordinate on the sky or within a spectrum. The FITS Working Group of the International Astronomical Union has therefore produced this new Version 3.0 of the FITS standard, which is provided here in its entirety. In addition to describing the new features in FITS, numerous editorial changes were made to the previous version to clarify and reorganize many of the sections. Also included are some appendices which are not formally part of the standard. The FITS standard is likely to undergo further evolution, in which case the latest version may be found on the FITS Support Office Web site at http://fits.gsfc.nasa.gov/, which also provides many links to FITS-related resources.

Investigation of the binding of a carbohydrate-mimetic peptide to its complementary anticarbohydrate antibody by STD-NMR spectroscopy and molecular-dynamics simulations.

PubMed

Szczepina, Monica G; Bleile, Dustin W; Pinto, B Mario

2011-10-04

Saturation transfer difference (STD)-NMR spectroscopy was used to probe experimentally the bioactive solution conformation of the carbohydrate mimic MDWNMHAA 1 of the O-polysaccharide of Shigella flexneri Y when bound to its complementary antibody, mAb SYA/J6. Molecular dynamics simulations using the ZymeCAD™ Molecular Dynamics platform were also undertaken to give a more accurate picture of the conformational flexibility and the possibilities for bound ligand conformations. The ligand topology, or the dynamic epitope, was mapped with the CORCEMA-ST (COmplete Relaxation and Conformational Exchange Matrix Analysis of Saturation Transfer) program that calculates a total matrix analysis of relaxation and exchange effects to generate predicted STD-NMR intensities from simulation. The comparison of these predicted STD enhancements with experimental data was used to select a representative binding mode. A protocol that employed theoretical STD effects calculated at snapshots during the entire course of a molecular dynamics (MD) trajectory of the peptide bound to the Fv portion of the antibody, and not the averaged atomic positions of receptor-ligand complexes, was also examined. In addition, the R factor was calculated on the basis of STD (fit) to avoid T1 bias, and an effective R factor, R(eff), was defined such that if the calculated STD (fit) for proton k was within error of the experimental STD (fit) for proton k, then that calculated STD (fit) for proton k was not included in the calculation of the R factor. This protocol was effective in deriving the antibody-bound solution conformation of the peptide which also differed from the bound conformation determined by X-ray crystallography; however, several discrepancies between experimental and calculated STD (fit) values were observed. The bound conformation was therefore further refined with a simulated annealing refinement protocol known as STD-NMR intensity-restrained CORCEMA optimization (SICO) to give a more accurate representation of the bound peptide epitope. Further optimization was required in this case, but a satisfactory correlation between experimental and calculated STD values was obtained. Attempts were also made to obtain STD enhancements with a synthetic pentasaccharide hapten, corresponding to the O-polysaccharide, while bound to the antibody. However, unfavorable kinetics of binding in this system prevented sufficient STD build-up, which, in turn, hindered a rigorous analysis via full STD build-up curves. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Physical Fitness of Adults with an Intellectual Disability: A 13-Year Follow-up Study.

ERIC Educational Resources Information Center

Graham, Andrew; Reid, Greg

2000-01-01

Examined changes in physical fitness of middle-aged adults with mental retardation over 13 years. The subjects had participated in a physical fitness study in 1983. They were re-evaluated for cardiovascular endurance, muscular strength, muscular endurance, flexibility, and body composition. Fitness levels declined over the 13 years and were low…

On-chip dynamic stress control for cancer cell evolution study

NASA Astrophysics Data System (ADS)

Liu, Liyu; Austin, Robert

2010-03-01

The growth and spreading of cancer in host organisms is an evolutionary process. Cells accumulate mutations that help them adapt to changing environments and to obtain survival fitness. However, all cancer--promoting mutations do not occur at once. Cancer cells face selective environmental pressures that drive their evolution in stages. In traditional cancer studies, environmental stress is usually homogenous in space and difficult to change in time. Here, we propose a microfluidic chip employing embedded dynamic traps to generate dynamic heterogeneous microenvironments for cancer cells in evolution studies. Based on polydimethylsiloxane (PDMS) flexible diaphragms, these traps are able to enclose and shield cancer cells or expose them to external environmental stress. Digital controls for each trap determine the nutrition, antibiotics, CO2/O2 conditions, and temperatures to which trapped cells are subjected. Thus, the stress applied to cells can be varied in intensity and duration in each trap independently. The chip can also output cells from specific traps for sequencing and other biological analysis. Hence our design simultaneously monitors and analyzes cell evolution behaviors under dynamic stresses.

"Finding an Appropriate Fit for Me": Examining the (In)Flexibilities of International Distance Learning

ERIC Educational Resources Information Center

Selwyn, Neil

2011-01-01

The concept of "flexibility" lies at the heart of contemporary post-compulsory education. Educational institutions are now expected to take a flexible approach to their provision of courses, as well as staffing, curriculum and assessment arrangements. Similarly, individual learners are expected to take an increasingly pragmatic,…

Polymer absorption in dense polymer brushes vs. polymer adsorption on the brush-solvent interface

NASA Astrophysics Data System (ADS)

Milchev, Andrey; Binder, Kurt

2014-06-01

Molecular-dynamics simulations of a coarse-grained model of a dense brush of flexible polymers (of type A) interacting with a long flexible macromolecule (of type B) are presented, considering the case of an attractive AB interaction, while effective interactions between AA and BB pairs of monomers are repulsive. Varying the strength \\varepsilon_{AB} of the attraction between unlike monomers, an adsorption transition at some critical value \\varepsilon^c_{AB} is found, where the B-chain is bound to the brush-solvent interface, similar to the adsorption on a planar solid substrate. However, when \\varepsilon_{AB} is much higher than \\varepsilon^c_{AB} , the long macromolecule is gradually “sucked in” the brush, developing many pieces that are locally stretched in the z-direction perpendicular to the substrate, in order to fit between the brush chains. The resulting hairpin-like structures of the absorbed chain shows up via oscillatory decay of the bond vector autocorrelation function. Chain relaxation is only possible via reptation.

Effects of Buddhism walking meditation on depression, functional fitness, and endothelium-dependent vasodilation in depressed elderly.

PubMed

Prakhinkit, Susaree; Suppapitiporn, Siriluck; Tanaka, Hirofumi; Suksom, Daroonwan

2014-05-01

The objectives of this study were to determine the effects of the novel Buddhism-based walking meditation (BWM) and the traditional walking exercise (TWE) on depression, functional fitness, and vascular reactivity. This was a randomized exercise intervention study. The study was conducted in a university hospital setting. Forty-five elderly participants aged 60-90 years with mild-to-moderate depressive symptoms were randomly allocated to the sedentary control, TWE, and BWM groups. The BWM program was based on aerobic walking exercise incorporating the Buddhist meditations performed 3 times/week for 12 weeks. Depression score, functional fitness, and endothelium-dependent vasodilation as measured by the flow-mediated dilation (FMD) were the outcome measures used. Muscle strength, flexibility, agility, dynamic balance, and cardiorespiratory endurance increased in both exercise groups (p<0.05). Depression score decreased (p<0.05) only in the BWM group. FMD improved (p<0.05) in both exercise groups. Significant reduction in plasma cholesterol, triglyceride, high-density lipoprotein cholesterol, and C-reactive protein were found in both exercise groups, whereas low-density lipoprotein cholesterol, cortisol, and interleukin-6 concentrations decreased only in the BWM group. Buddhist walking meditation was effective in reducing depression, improving functional fitness and vascular reactivity, and appears to confer greater overall improvements than the traditional walking program.

Adoption of Canada's Physical Activity Guide and Handbook for Older Adults: impact on functional fitness and energy expenditure.

PubMed

Jiang, Xuesong; Cooper, Juliette; Porter, Michelle M; Ready, A Elizabeth

2004-08-01

This study investigated whether a behaviour change program, based on Canada's Physical Activity Guide and Handbook to Healthy Active Living for Older Adults (Health Canada, 1999a), would elicit greater benefits than adoption of the guide and handbook alone. Fifteen older adults received the guide and accompanying handbook and completed the 8-week behaviour change program (mean age 73.2 +/- 5.2 yrs), while 14 others received only the guide and handbook (mean age 76.8 +/- 10.0 yrs). Functional fitness (lower body strength/endurance, flexibility, agility/dynamic balance) (Rikli and Jones, 1999), and estimated energy expenditure (DiPietro et al., 1993) were measured at baseline and after 8 weeks. Lower body strength/endurance and agility/dynamic balance differed between groups at baseline, p < 0.05. All three functional fitness tests improved in both groups over time, p< 0.05. Estimated energy expended in physical activity increased in both groups over time, p < 0.05; however, there was a significantly greater increase in the behaviour-change group (Group x Time interaction, p < 0.05). Participant response to using the guide and handbook was positive. These results indicate that introduction to Canada's Physical Activity Guide and Handbook to Healthy Active Living for Older Adults leads to benefits, whether or not accompanied by program supports. The group receiving the behaviour change program had a greater increase in energy expenditure, which suggests that such an intervention may ultimately lead to greater health benefits.

The flow dynamics behind a flexible finite cylinder as a flexible agitator

NASA Astrophysics Data System (ADS)

Yong, T. H.; Chan, H. B.; Dol, S. S.; Wee, S. K.; Kumar, P.

2017-06-01

This paper investigates the flow dynamics behind a flexible finite cylinder in a single-phase flow using a water tunnel. The cylinder was individually submerged in water at ReD = 4000, 6000 and 8000. The cylinder investigated has a AR = 10 and 16 and is made of EVA in order to achieve the lower stiffness for flexibility. A same AR of its aluminium rigid cylinder was investigated to serve as a benchmark to the flow dynamics behind a flexible cylinder. The results the downwash that hinders the transportation of vortices to the downstream was diminished. As a direct consequence of this phenomenon, the turbulence production has seen significant improvement for flexible finite cylinder.

Recursive dynamics for flexible multibody systems using spatial operators

NASA Technical Reports Server (NTRS)

Jain, A.; Rodriguez, G.

1990-01-01

Due to their structural flexibility, spacecraft and space manipulators are multibody systems with complex dynamics and possess a large number of degrees of freedom. Here the spatial operator algebra methodology is used to develop a new dynamics formulation and spatially recursive algorithms for such flexible multibody systems. A key feature of the formulation is that the operator description of the flexible system dynamics is identical in form to the corresponding operator description of the dynamics of rigid multibody systems. A significant advantage of this unifying approach is that it allows ideas and techniques for rigid multibody systems to be easily applied to flexible multibody systems. The algorithms use standard finite-element and assumed modes models for the individual body deformation. A Newton-Euler Operator Factorization of the mass matrix of the multibody system is first developed. It forms the basis for recursive algorithms such as for the inverse dynamics, the computation of the mass matrix, and the composite body forward dynamics for the system. Subsequently, an alternative Innovations Operator Factorization of the mass matrix, each of whose factors is invertible, is developed. It leads to an operator expression for the inverse of the mass matrix, and forms the basis for the recursive articulated body forward dynamics algorithm for the flexible multibody system. For simplicity, most of the development here focuses on serial chain multibody systems. However, extensions of the algorithms to general topology flexible multibody systems are described. While the computational cost of the algorithms depends on factors such as the topology and the amount of flexibility in the multibody system, in general, it appears that in contrast to the rigid multibody case, the articulated body forward dynamics algorithm is the more efficient algorithm for flexible multibody systems containing even a small number of flexible bodies. The variety of algorithms described here permits a user to choose the algorithm which is optimal for the multibody system at hand. The availability of a number of algorithms is even more important for real-time applications, where implementation on parallel processors or custom computing hardware is often necessary to maximize speed.

Crystal structures reveal an induced-fit binding of a substrate-like Aza-peptide epoxide to SARS coronavirus main peptidase.

PubMed

Lee, Ting-Wai; Cherney, Maia M; Liu, Jie; James, Karen Ellis; Powers, James C; Eltis, Lindsay D; James, Michael N G

2007-02-23

The SARS coronavirus main peptidase (SARS-CoV M(pro)) plays an essential role in the life-cycle of the virus and is a primary target for the development of anti-SARS agents. Here, we report the crystal structure of M(pro) at a resolution of 1.82 Angstroms, in space group P2(1) at pH 6.0. In contrast to the previously reported structure of M(pro) in the same space group at the same pH, the active sites and the S1 specificity pockets of both protomers in the structure of M(pro) reported here are in the catalytically competent conformation, suggesting their conformational flexibility. We report two crystal structures of M(pro) having an additional Ala at the N terminus of each protomer (M(+A(-1))(pro)), both at a resolution of 2.00 Angstroms, in space group P4(3)2(1)2: one unbound and one bound by a substrate-like aza-peptide epoxide (APE). In the unbound form, the active sites and the S1 specificity pockets of both protomers of M(+A(-1))(pro) are observed in a collapsed (catalytically incompetent) conformation; whereas they are in an open (catalytically competent) conformation in the APE-bound form. The observed conformational flexibility of the active sites and the S1 specificity pockets suggests that these parts of M(pro) exist in dynamic equilibrium. The structural data further suggest that the binding of APE to M(pro) follows an induced-fit model. The substrate likely also binds in an induced-fit manner in a process that may help drive the catalytic cycle.

A High Performance Computing Approach to the Simulation of Fluid Solid Interaction Problems with Rigid and Flexible Components (Open Access Publisher’s Version)

DTIC Science & Technology

2014-08-01

performance computing, smoothed particle hydrodynamics, rigid body dynamics, flexible body dynamics ARMAN PAZOUKI ∗, RADU SERBAN ∗, DAN NEGRUT ∗ A...HIGH PERFORMANCE COMPUTING APPROACH TO THE SIMULATION OF FLUID-SOLID INTERACTION PROBLEMS WITH RIGID AND FLEXIBLE COMPONENTS This work outlines a unified...are implemented to model rigid and flexible multibody dynamics. The two- way coupling of the fluid and solid phases is supported through use of

Cardiorespiratory Fitness and the Flexible Modulation of Cognitive Control in Preadolescent Children

ERIC Educational Resources Information Center

Pontifex, Matthew B.; Raine, Lauren B.; Johnson, Christopher R.; Chaddock, Laura; Voss, Michelle W.; Cohen, Neal J.; Kramer, Arthur F.; Hillman, Charles H.

2011-01-01

The influence of cardiorespiratory fitness on the modulation of cognitive control was assessed in preadolescent children separated into higher- and lower-fit groups. Participants completed compatible and incompatible stimulus-response conditions of a modified flanker task, consisting of congruent and incongruent arrays, while ERPs and task…

Pilates and Physical Education: A Natural Fit

ERIC Educational Resources Information Center

Kloubec, June; Banks, Aaron L.

2004-01-01

In a time period characterized by the continual decline of fitness and physical activity among American youths, Pilates can provide physical educators a unique activity that will improve fitness and stimulate the cognitive domain of today's students. Because the Pilates method of exercise encourages the development of strong and flexible muscles…

Estimating and modelling cure in population-based cancer studies within the framework of flexible parametric survival models.

PubMed

Andersson, Therese M L; Dickman, Paul W; Eloranta, Sandra; Lambert, Paul C

2011-06-22

When the mortality among a cancer patient group returns to the same level as in the general population, that is, the patients no longer experience excess mortality, the patients still alive are considered "statistically cured". Cure models can be used to estimate the cure proportion as well as the survival function of the "uncured". One limitation of parametric cure models is that the functional form of the survival of the "uncured" has to be specified. It can sometimes be hard to find a survival function flexible enough to fit the observed data, for example, when there is high excess hazard within a few months from diagnosis, which is common among older age groups. This has led to the exclusion of older age groups in population-based cancer studies using cure models. Here we have extended the flexible parametric survival model to incorporate cure as a special case to estimate the cure proportion and the survival of the "uncured". Flexible parametric survival models use splines to model the underlying hazard function, and therefore no parametric distribution has to be specified. We have compared the fit from standard cure models to our flexible cure model, using data on colon cancer patients in Finland. This new method gives similar results to a standard cure model, when it is reliable, and better fit when the standard cure model gives biased estimates. Cure models within the framework of flexible parametric models enables cure modelling when standard models give biased estimates. These flexible cure models enable inclusion of older age groups and can give stage-specific estimates, which is not always possible from parametric cure models. © 2011 Andersson et al; licensee BioMed Central Ltd.

Estimating and modelling cure in population-based cancer studies within the framework of flexible parametric survival models

PubMed Central

2011-01-01

Background When the mortality among a cancer patient group returns to the same level as in the general population, that is, the patients no longer experience excess mortality, the patients still alive are considered "statistically cured". Cure models can be used to estimate the cure proportion as well as the survival function of the "uncured". One limitation of parametric cure models is that the functional form of the survival of the "uncured" has to be specified. It can sometimes be hard to find a survival function flexible enough to fit the observed data, for example, when there is high excess hazard within a few months from diagnosis, which is common among older age groups. This has led to the exclusion of older age groups in population-based cancer studies using cure models. Methods Here we have extended the flexible parametric survival model to incorporate cure as a special case to estimate the cure proportion and the survival of the "uncured". Flexible parametric survival models use splines to model the underlying hazard function, and therefore no parametric distribution has to be specified. Results We have compared the fit from standard cure models to our flexible cure model, using data on colon cancer patients in Finland. This new method gives similar results to a standard cure model, when it is reliable, and better fit when the standard cure model gives biased estimates. Conclusions Cure models within the framework of flexible parametric models enables cure modelling when standard models give biased estimates. These flexible cure models enable inclusion of older age groups and can give stage-specific estimates, which is not always possible from parametric cure models. PMID:21696598

A Quasi-Parametric Method for Fitting Flexible Item Response Functions

ERIC Educational Resources Information Center

Liang, Longjuan; Browne, Michael W.

2015-01-01

If standard two-parameter item response functions are employed in the analysis of a test with some newly constructed items, it can be expected that, for some items, the item response function (IRF) will not fit the data well. This lack of fit can also occur when standard IRFs are fitted to personality or psychopathology items. When investigating…

Definition of the Flexible Image Transport System (FITS), version 3.0

NASA Astrophysics Data System (ADS)

Pence, W. D.; Chiappetti, L.; Page, C. G.; Shaw, R. A.; Stobie, E.

2010-12-01

The Flexible Image Transport System (FITS) has been used by astronomers for over 30 years as a data interchange and archiving format; FITS files are now handled by a wide range of astronomical software packages. Since the FITS format definition document (the “standard”) was last printed in this journal in 2001, several new features have been developed and standardized, notably support for 64-bit integers in images and tables, variable-length arrays in tables, and new world coordinate system conventions which provide a mapping from an element in a data array to a physical coordinate on the sky or within a spectrum. The FITS Working Group of the International Astronomical Union has therefore produced this new version 3.0 of the FITS standard, which is provided here in its entirety. In addition to describing the new features in FITS, numerous editorial changes were made to the previous version to clarify and reorganize many of the sections. Also included are some appendices which are not formally part of the standard. The FITS standard is likely to undergo further evolution, in which case the latest version may be found on the FITS Support Office Web site at http://fits.gsfc.nasa.gov/, which also provides many links to FITS-related resources.

In-Factory Learning - Qualification For The Factory Of The Future

NASA Astrophysics Data System (ADS)

Quint, Fabian; Mura, Katharina; Gorecky, Dominic

2015-07-01

The Industry 4.0 vision anticipates that internet technologies will find their way into future factories replacing traditional components by dynamic and intelligent cyber-physical systems (CPS) that combine the physical objects with their digital representation. Reducing the gap between the real and digital world makes the factory environment more flexible, more adaptive, but also more complex for the human workers. Future workers require interdisciplinary competencies from engineering, information technology, and computer science in order to understand and manage the diverse interrelations between physical objects and their digital counterpart. This paper proposes a mixed-reality based learning environment, which combines physical objects and visualisation of digital content via Augmented Reality. It uses reality-based interaction in order to make the dynamic interrelations between real and digital factory visible and tangible. We argue that our learning system does not work as a stand-alone solution, but should fit into existing academic and advanced training curricula.

FITS and PDS4: Planetary Surface Data Interoperability Made Easier

NASA Astrophysics Data System (ADS)

Marmo, C.; Hare, T. M.; Erard, S.; Cecconi, B.; Minin, M.; Rossi, A. P.; Costard, F.; Schmidt, F.

2018-04-01

This abstract describes how Flexible Image Transport System (FITS) can be used in planetary surface investigations, and how its metadata can easily be inserted in the PDS4 metadata distribution model.

The association of socio-economic factors with physical fitness and activity behaviours, spinal posture and retinal vessel parameters in first graders in urban Switzerland.

PubMed

Imhof, Katharina; Faude, Oliver; Donath, Lars; Bean-Eisenhut, Salome; Hanssen, Henner; Zahner, Lukas

2016-01-01

Socio-economic status during childhood has been shown to be a strong predictor of adult health outcome. Therefore, we examined associations of parental educational level, household income and migrant background with physical fitness, spinal flexibility, spinal posture as well as retinal vessel diameters in children of an urban Swiss region. A total of 358 first graders of the Swiss canton Basel-Stadt (age: 7.3, SD: 0.4) were examined. Physical fitness (20 m shuttle run test, 20 m sprint, jumping sidewards and balancing backwards), spinal flexibility and spinal posture (MediMouse®, Idiag, Fehraltdorf, Switzerland) and retinal microcirculation (Static Retinal Vessel Analyzer, Imedos Systems UG, Jena, Germany) were assessed. Parental education, household income, migrant background and activity behaviour were evaluated with a questionnaire. Parental education was associated with child aerobic fitness (P = 0.03) and screen time (P < 0.001). Household income was associated with jumping sidewards (P = 0.009), balancing backwards (P = 0.03) and sports club participation (P = 0.02). Migrant background was associated with BMI (P = 0.001), body fat (P = 0.03), aerobic fitness (P = 0.007), time spent playing outdoors (P < 0.001) and screen time (P < 0.001). For spinal flexibility and retinal vessel diameter, no associations were found (0.06 < P < 0.8). Low parental education, low household income and a migrant background are associated with poor physical fitness, higher BMI and body fat percentage and low-activity behaviour.

Structural Dynamics and Control Interaction of Flexible Structures

NASA Technical Reports Server (NTRS)

Ryan, Robert S. (Editor); Scofield, Harold N. (Editor)

1987-01-01

A workshop on structural dynamics and control interaction of flexible structures was held to promote technical exchange between the structural dynamics and control disciplines, foster joint technology, and provide a forum for discussing and focusing critical issues in the separate and combined areas. Issues and areas of emphasis were identified in structure-control interaction for the next generation of flexible systems.

Dynamic modeling and hierarchical compound control of a novel 2-DOF flexible parallel manipulator with multiple actuation modes

NASA Astrophysics Data System (ADS)

Liang, Dong; Song, Yimin; Sun, Tao; Jin, Xueying

2018-03-01

This paper addresses the problem of rigid-flexible coupling dynamic modeling and active control of a novel flexible parallel manipulator (PM) with multiple actuation modes. Firstly, based on the flexible multi-body dynamics theory, the rigid-flexible coupling dynamic model (RFDM) of system is developed by virtue of the augmented Lagrangian multipliers approach. For completeness, the mathematical models of permanent magnet synchronous motor (PMSM) and piezoelectric transducer (PZT) are further established and integrated with the RFDM of mechanical system to formulate the electromechanical coupling dynamic model (ECDM). To achieve the trajectory tracking and vibration suppression, a hierarchical compound control strategy is presented. Within this control strategy, the proportional-differential (PD) feedback controller is employed to realize the trajectory tracking of end-effector, while the strain and strain rate feedback (SSRF) controller is developed to restrain the vibration of the flexible links using PZT. Furthermore, the stability of the control algorithm is demonstrated based on the Lyapunov stability theory. Finally, two simulation case studies are performed to illustrate the effectiveness of the proposed approach. The results indicate that, under the redundant actuation mode, the hierarchical compound control strategy can guarantee the flexible PM achieves singularity-free motion and vibration attenuation within task workspace simultaneously. The systematic methodology proposed in this study can be conveniently extended for the dynamic modeling and efficient controller design of other flexible PMs, especially the emerging ones with multiple actuation modes.

Experimental validation of flexible robot arm modeling and control

NASA Technical Reports Server (NTRS)

Ulsoy, A. Galip

1989-01-01

Flexibility is important for high speed, high precision operation of lightweight manipulators. Accurate dynamic modeling of flexible robot arms is needed. Previous work has mostly been based on linear elasticity with prescribed rigid body motions (i.e., no effect of flexible motion on rigid body motion). Little or no experimental validation of dynamic models for flexible arms is available. Experimental results are also limited for flexible arm control. Researchers include the effects of prismatic as well as revolute joints. They investigate the effect of full coupling between the rigid and flexible motions, and of axial shortening, and consider the control of flexible arms using only additional sensors.

Comprehensive modeling and control of flexible flapping wing micro air vehicles

NASA Astrophysics Data System (ADS)

Nogar, Stephen Michael

Flapping wing micro air vehicles hold significant promise due to the potential for improved aerodynamic efficiency, enhanced maneuverability and hover capability compared to fixed and rotary configurations. However, significant technical challenges exist to due the lightweight, highly integrated nature of the vehicle and coupling between the actuators, flexible wings and control system. Experimental and high fidelity analysis has demonstrated that aeroelastic effects can change the effective kinematics of the wing, reducing vehicle stability. However, many control studies for flapping wing vehicles do not consider these effects, and instead validate the control strategy with simple assumptions, including rigid wings, quasi-steady aerodynamics and no consideration of actuator dynamics. A control evaluation model that includes aeroelastic effects and actuator dynamics is developed. The structural model accounts for geometrically nonlinear behavior using an implicit condensation technique and the aerodynamic loads are found using a time accurate approach that includes quasi-steady, rotational, added mass and unsteady effects. Empirically based parameters in the model are fit using data obtained from a higher fidelity solver. The aeroelastic model and its ingredients are compared to experiments and computations using models of higher fidelity, and indicate reasonable agreement. The developed control evaluation model is implemented in a previously published, baseline controller that maintains stability using an asymmetric wingbeat, known as split-cycle, along with changing the flapping frequency and wing bias. The model-based controller determines the control inputs using a cycle-averaged, linear control design model, which assumes a rigid wing and no actuator dynamics. The introduction of unaccounted for dynamics significantly degrades the ability of the controller to track a reference trajectory, and in some cases destabilizes the vehicle. This demonstrates the importance of considering coupled aeroelastic and actuator dynamics in closed-loop control of flapping wings. A controller is developed that decouples the normal form of the vehicle dynamics, which accounts for coupling of the forces and moments acting on the vehicle and enables enhanced tuning capabilities. This controller, using the same control design model as the baseline controller, stabilizes the system despite the uncertainty between the control design and evaluation models. The controller is able to stabilize cases with significant wing flexibility and limited actuator capabilities, despite a reduction in control effectiveness. Additionally, to achieve a minimally actuated vehicle, the wing bias mechanism is removed. Using the same control design methodology, increased performance is observed compared to the baseline controller. However, due to the dependence on the split-cycle mechanism to generate a pitching moment instead of wing bias, the controller is more susceptible to instability from wing flexibility and limited actuator capacity. This work highlights the importance of coupled dynamics in the design and control of flapping wing micro air vehicles. Future enhancements to this work should focus on the reduced order structural and aerodynamics models. Applications include using the developed dynamics model to evaluate other kinematics and control schemes, ultimately enabling improved vehicle and control design.

Blade loss transient dynamics analysis with flexible bladed disk

NASA Technical Reports Server (NTRS)

Gallardo, V. C.; Black, G.; Bach, L.; Cline, S.; Storace, A.

1983-01-01

The transient dynamic response of a flexible bladed disk on a flexible rotor in a two rotor system is formulated by modal synthesis and a Lagrangian approach. Only the nonequilibrated one diameter flexible mode is considered for the flexible bladed disk, while the two flexible rotors are represented by their normal modes. The flexible bladed disk motion is modeled as a combination of two one diameter standing waves, and is coupled inertially and gyroscopically to the flexible rotors. Application to a two rotor model shows that a flexible bladed disk on one rotor can be driven into resonance by an unbalance in the other rotor, and at a frequency equal to the difference in the rotor speeds.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

Kongsberg Engineering a.s. has developed an oil loading system for the Central North Sea, in 492-ft waters, which is not permanent, is safer, economical and withstands the environmental forces in the area. The ''Subload'' system is based on loading directly from a seafloor terminal to two 78,000 dwt dynamically positioned shuttle tankers. Upon arrival at the field, a shuttle tanker fitted with an SPM loading yoke and a riser reel deploys a 16-in. flexible riser attached to a lower riser package fitted with thrusters. Controlled by signals from a special high-accuracy underwater maneuver the lower riser end into docking positionmore » with the seafloor terminal. The terminal is located at the end of a two-km, 28-in. pipe line from the production platform. Presentation of the system, the company said that the diverless hookup procedure between the intrument-controlled riser connection and the subsea wellhead requires 45 minutes. The shuttle tanker loading could be completed twice a day in seven and a half hours per operation.« less

Damped-Dynamics Flexible Fitting

PubMed Central

Kovacs, Julio A.; Yeager, Mark; Abagyan, Ruben

2008-01-01

In fitting atomic structures into EM maps, it often happens that the map corresponds to a different conformation of the structure. We have developed a new methodology to handle these situations that preserves the covalent geometry of the structure and allows the modeling of large deformations. The first goal is achieved by working in generalized coordinates (positional and internal coordinates), and the second by avoiding harmonic potentials. Instead, we use dampers (shock absorbers) between every pair of atoms, combined with a force field that attracts the atomic structure toward incompletely occupied regions of the EM map. The trajectory obtained by integrating the resulting equations of motion converges to a conformation that, in our validation cases, was very close to the target atomic structure. Compared to current methods, our approach is more efficient and robust against wrong solutions and to overfitting, and does not require user intervention or subjective decisions. Applications to the computation of transition pathways between known conformers, homology and loop modeling, as well as protein docking, are also discussed. PMID:18586844

Damped-dynamics flexible fitting.

PubMed

Kovacs, Julio A; Yeager, Mark; Abagyan, Ruben

2008-10-01

In fitting atomic structures into EM maps, it often happens that the map corresponds to a different conformation of the structure. We have developed a new methodology to handle these situations that preserves the covalent geometry of the structure and allows the modeling of large deformations. The first goal is achieved by working in generalized coordinates (positional and internal coordinates), and the second by avoiding harmonic potentials. Instead, we use dampers (shock absorbers) between every pair of atoms, combined with a force field that attracts the atomic structure toward incompletely occupied regions of the EM map. The trajectory obtained by integrating the resulting equations of motion converges to a conformation that, in our validation cases, was very close to the target atomic structure. Compared to current methods, our approach is more efficient and robust against wrong solutions and to overfitting, and does not require user intervention or subjective decisions. Applications to the computation of transition pathways between known conformers, homology and loop modeling, as well as protein docking, are also discussed.

Physical activity and functional fitness in institutionalized vs. independently living elderly: a comparison of 70-80-year-old city-dwellers.

PubMed

Król-Zielińska, Magdalena; Kusy, Krzysztof; Zieliński, Jacek; Osiński, Wiesław

2011-01-01

The purpose of the study was to compare the level of energy expenditure due to physical activity (EEPA) and functional fitness (FF) in 59 women and 82 men aged 70-80 years, divided into three groups: permanent residents in assisted-living facilities (ALFs), participants in adult day care centers (DCCs) and older people living independently, members in community senior centers (CSCs). EEPA and FF were analyzed taking into consideration sex differences. The energy expenditure tended to be lower in DCCs and ALFs subjects than in CSCs members, but significant differences were obtained only in women. Women in different living settings differed only in endurance. In men, the differences were clear in most tests (endurance, strength, agility/dynamic balance) except for flexibility. Institutionalization was connected with a significantly lower level of FF and equalization of sex differences. Education seemed to be an important factor influencing the level of FF in men. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Characterizing Solution Surface Loop Conformational Flexibility of the GM2 Activator Protein

PubMed Central

2015-01-01

GM2AP has a β-cup topology with numerous X-ray structures showing multiple conformations for some of the surface loops, revealing conformational flexibility that may be related to function, where function is defined as either membrane binding associated with ligand binding and extraction or interaction with other proteins. Here, site-directed spin labeling (SDSL) electron paramagnetic resonance (EPR) spectroscopy and molecular dynamic (MD) simulations are used to characterize the mobility and conformational flexibility of various structural regions of GM2AP. A series of 10 single cysteine amino acid substitutions were generated, and the constructs were chemically modified with the methanethiosulfonate spin label. Continuous wave (CW) EPR line shapes were obtained and subsequently simulated using the microscopic order macroscopic disorder (MOMD) program. Line shapes for sites that have multiple conformations in the X-ray structures required two spectral components, whereas spectra of the remaining sites were adequately fit with single-component parameters. For spin labeled sites L126C and I66C, spectra were acquired as a function of temperature, and simulations provided for the determination of thermodynamic parameters associated with conformational change. Binding to GM2 ligand did not alter the conformational flexibility of the loops, as evaluated by EPR and NMR spectroscopies. These results confirm that the conformational flexibility observed in the surface loops of GM2AP crystals is present in solution and that the exchange is slow on the EPR time scale (>ns). Furthermore, MD simulation results are presented and agree well with the conformational heterogeneity revealed by SDSL. PMID:25127419

Re-evaluation of low-resolution crystal structures via interactive molecular-dynamics flexible fitting (iMDFF): a case study in complement C4.

PubMed

Croll, Tristan Ian; Andersen, Gregers Rom

2016-09-01

While the rapid proliferation of high-resolution structures in the Protein Data Bank provides a rich set of templates for starting models, it remains the case that a great many structures both past and present are built at least in part by hand-threading through low-resolution and/or weak electron density. With current model-building tools this task can be challenging, and the de facto standard for acceptable error rates (in the form of atomic clashes and unfavourable backbone and side-chain conformations) in structures based on data with dmax not exceeding 3.5 Å reflects this. When combined with other factors such as model bias, these residual errors can conspire to make more serious errors in the protein fold difficult or impossible to detect. The three recently published 3.6-4.2 Å resolution structures of complement C4 (PDB entries 4fxg, 4fxk and 4xam) rank in the top quartile of structures of comparable resolution both in terms of Rfree and MolProbity score, yet, as shown here, contain register errors in six β-strands. By applying a molecular-dynamics force field that explicitly models interatomic forces and hence excludes most physically impossible conformations, the recently developed interactive molecular-dynamics flexible fitting (iMDFF) approach significantly reduces the complexity of the conformational space to be searched during manual rebuilding. This substantially improves the rate of detection and correction of register errors, and allows user-guided model building in maps with a resolution lower than 3.5 Å to converge to solutions with a stereochemical quality comparable to atomic resolution structures. Here, iMDFF has been used to individually correct and re-refine these three structures to MolProbity scores of <1.7, and strategies for working with such challenging data sets are suggested. Notably, the improved model allowed the resolution for complement C4b to be extended from 4.2 to 3.5 Å as demonstrated by paired refinement.

The effects of five weeks of kickboxing training on physical fitness

PubMed Central

Ouergui, Ibrahim; Hssin, Nizar; Haddad, Monoem; Padulo, Johnny; Franchini, Emerson; Gmada, Nabil; Bouhlel, Ezzedine

2014-01-01

Summary Aim: the purpose of this study was to examine the effect of kickboxing training on physical fitness. Methods: 30 subjects were randomized into a kickboxing-group (n=15) and control group (n=15). Each group trained approximately 1-hour per day, three-times per a week during five weeks. Muscle-power (upper-body: bench-press-test, medicine-ball-test; lower-body: squat-jump and counter-movement-jump-test), flexibility, speed and agility, aerobic (progressive maximal exercise test), anaerobic fitness (Wingate test) and body composition were assessed before and after the training period. Results: the kickboxing group showed significant improvement (p < 0.05) in upper-body muscle power, aerobic power, anaerobic fitness, flexibility, speed and agility after training whereas body composition, squat jump and counter movement jump (height, power and velocity components) did not change for both groups. Conclusion: kickboxing-practice was effective to change many physical variables. Thus, this activity can be useful for enhancing physical fitness, but complementary activities and/or nutritional interventions should be necessary. PMID:25332919

Measurement of Residual Flexibility for Substructures Having Prominent Flexible Interfaces

NASA Technical Reports Server (NTRS)

Tinker, Michael L.; Bookout, Paul S.

1994-01-01

Verification of a dynamic model of a constrained structure requires a modal survey test of the physical structure and subsequent modification of the model to obtain the best agreement possible with test data. Constrained-boundary or fixed-base testing has historically been the most common approach for verifying constrained mathematical models, since the boundary conditions of the test article are designed to match the actual constraints in service. However, there are difficulties involved with fixed-base testing, in some cases making the approach impractical. It is not possible to conduct a truly fixed-base test due to coupling between the test article and the fixture. In addition, it is often difficult to accurately simulate the actual boundary constraints, and the cost of designing and constructing the fixture may be prohibitive. For use when fixed-base testing proves impractical or undesirable, alternate free-boundary test methods have been investigated, including the residual flexibility technique. The residual flexibility approach has been treated analytically in considerable detail and has had limited frequency response measurements for the method. This concern is well-justified for a number of reasons. First, residual flexibilities are very small numbers, typically on the order of 1.0E-6 in/lb for translational diagonal terms, and orders of magnitude smaller for off-diagonal values. This poses difficulty in obtaining accurate and noise-free measurements, especially for points removed from the excitation source. A second difficulty encountered in residual measurements lies in obtaining a clean residual function in the process of subtracting synthesized modal data from a measured response function. Inaccuracies occur since modes are not subtracted exactly, but only to the accuracy of the curve fits for each mode; these errors are compounded with increasing distance from the excitation point. In this paper, the residual flexibility method is applied to a simple structure in both test and analysis. Measured and predicted residual functions are compared, and regions of poor data in the measured curves are described. It is found that for accurate residual measurements, frequency response functions having prominent stiffness lines in the acceleration/force format are needed. The lack of such stiffness lines increases measurement errors. Interface drive point frequency respose functions for shuttle orbiter payloads exhibit dominant stiffness lines, making the residual test approach a good candidate for payload modal tests when constrained tests are inappropriate. Difficulties in extracting a residual flexibility value from noisy test data are discussed. It is shown that use of a weighted second order least-squares curve fit of the measured residual function allows identification of residual flexibility that compares very well with predictions for the simple structure. This approach also provides an estimate of second order residual mass effects.

Fire fit: assessing comprehensive fitness and injury risk in the fire service.

PubMed

Poplin, Gerald S; Roe, Denise J; Burgess, Jefferey L; Peate, Wayne F; Harris, Robin B

2016-02-01

This study sought to develop a comprehensive measure of fitness that is predictive of injury risk and can be used in the fire service to assess individual-level health and fit-for-duty status. A retrospective occupational cohort of 799 career fire service employees was observed over the years 2005-2009. An equally weighted score for comprehensive fitness was calculated based on cardiovascular fitness, muscular strength, endurance, flexibility, and body composition. Repeated measures survival analyses were used to estimate the risk of any injury, sprain or strain, and exercise-related injuries in relation to comprehensive fitness. A well-distributed comprehensive fitness score was developed to distinguish three tiers of overall fitness status. Intraclass correlations identified flexibility, total grip strength, percent body fat, and resting heart rate as the most reliable fitness metrics, while push-ups, sit-ups, and aerobic capacity demonstrated poor reliability. In general, individuals with a lower comprehensive fitness status had an increased injury risk of injury as compared to the most fit individuals. The risk of any injury was 1.82 (95% CI 1.06-3.11) times as likely for the least fit individuals, as compared to individuals in the top fire fitness category, increasing to 2.90 (95% CI 1.48-5.66) when restricted to sprains and strains. This 5-year analysis of clinical occupational health assessments enabled the development of a relevant metric for relating comprehensive fitness with the risk of injury. Results were consistent with previous studies focused on cardiorespiratory fitness, but also less susceptible to inter-individual variability of discrete measurements.

Dynamic Flexibility and Proprioceptive Neuromuscular Facilitation.

ERIC Educational Resources Information Center

Hardy, Lew; Jones, David

1986-01-01

Two experiments are described which investigated whether results obtained in studies of static flexibility tranfer to dynamic flexibility. In both experiments, subjects were assigned to a group receiving proprioceptive neuromuscular facilitation training, ballistic stretching technique training or a control group. Results are presented and…

Feed-in Tariffs: Good Practices and Design Considerations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cox, Sadie; Esterly, Sean

2016-01-02

In recent years, feed-in tariff (FIT) activity has focused primarily on revisions to current policies, underscoring the need for stable and predictable, yet flexible, policy environments. This policy brief provides a primer on key FIT design elements, lessons from country experience, and support resources to enable more detailed and country-specific FIT policy design.

Effects of over-the-counter jaw-repositioning mouth guards on dynamic balance, flexibility, agility, strength, and power in college-aged male athletes.

PubMed

Golem, Devon L; Arent, Shawn M

2015-02-01

Improvements in muscular power and anaerobic performance have resulted from the use of jaw-repositioning mouth guards designed with advanced dental techniques. The high cost of such techniques has dissuaded the widespread use. Recently, more affordable, over-the-counter (OTC) jaw-repositioning mouth guards have become available. The primary objective of this study was to examine the effects of 2 OTC jaw-repositioning mouth guards on muscular power and strength performance in college-aged male athletes. It was hypothesized that similar to previous observations with advanced dentistry-designed mouth guards, OTC jaw-repositioning mouth guards would impart positive effects on muscular power but not have any effect on muscular strength. Secondary objectives of this study included the examination of the effects of 2 OTC jaw-repositioning mouth guards on other variables related to athletic performance. Male collegiate athletes (N = 20) participated in 4 separate testing sessions that consisted of assessment of muscular power, dynamic balance, flexibility, agility, and muscular strength. The 4 conditions, 1 per testing session, were assigned in a randomized order and consisted of a no-mouth guard control (CON), a placebo mouth guard, a self-adapted jaw-repositioning mouth guard (SA), and a custom-fitted jaw-repositioning mouth guard (CF). No significant differences were observed between conditions in muscular power (p = 0.78), dynamic balance (p = 0.99), agility (p = 0.22), or muscular strength (p = 0.47). The CF had significantly lower hip flexion than the CON (p = 0.014) and had significantly greater lumbar spine lateral flexion compared with the SA condition (p = 0.054). However, these flexibility differences lack practical relevance as the effect sizes remain very small (ES = -0.27 and -0.14, respectively). In conclusion, the jaw-repositioning technique used in the design of these OTC mouth guards did not affect performance. It is important to note that negative effects were not observed indicating that mouth guard use did not impede performance.

Parameterization of backbone flexibility in a coarse-grained force field for proteins (COFFDROP) derived from all-atom explicit-solvent molecular dynamics simulations of all possible two-residue peptides

PubMed Central

Frembgen-Kesner, Tamara; Andrews, Casey T.; Li, Shuxiang; Ngo, Nguyet Anh; Shubert, Scott A.; Jain, Aakash; Olayiwola, Oluwatoni; Weishaar, Mitch R.; Elcock, Adrian H.

2015-01-01

Recently, we reported the parameterization of a set of coarse-grained (CG) nonbonded potential functions, derived from all-atom explicit-solvent molecular dynamics (MD) simulations of amino acid pairs, and designed for use in (implicit-solvent) Brownian dynamics (BD) simulations of proteins; this force field was named COFFDROP (COarse-grained Force Field for Dynamic Representations Of Proteins). Here, we describe the extension of COFFDROP to include bonded backbone terms derived from fitting to results of explicit-solvent MD simulations of all possible two-residue peptides containing the 20 standard amino acids, with histidine modeled in both its protonated and neutral forms. The iterative Boltzmann inversion (IBI) method was used to optimize new CG potential functions for backbone-related terms by attempting to reproduce angle, dihedral and distance probability distributions generated by the MD simulations. In a simple test of the transferability of the extended force field, the angle, dihedral and distance probability distributions obtained from BD simulations of 56 three-residue peptides were compared to results from corresponding explicit-solvent MD simulations. In a more challenging test of the COFFDROP force field, it was used to simulate eight intrinsically disordered proteins and was shown to quite accurately reproduce the experimental hydrodynamic radii (Rhydro), provided that the favorable nonbonded interactions of the force field were uniformly scaled downwards in magnitude. Overall, the results indicate that the COFFDROP force field is likely to find use in modeling the conformational behavior of intrinsically disordered proteins and multi-domain proteins connected by flexible linkers. PMID:26574429

Physical fitness differences between prepubescent boys and girls.

PubMed

Marta, Carlos C; Marinho, Daniel A; Barbosa, Tiago M; Izquierdo, Mikel; Marques, Mário C

2012-07-01

The purpose of this study was to analyze in which physical capabilities boys and girls are closer or distant. An additional objective was to find which of the body fat, physical activity, and somatotype factors have a greater effect on prepubescent children's physical fitness. This was a cross-sectional study involving 312 children (10.8 ± 0.4 years). The physical fitness assessment employed sets of aerobic fitness, strength, flexibility, speed, agility, and balance. The boys presented higher values in all selected tests, except tests of balance and flexibility, in which girls scored better. Gender differences in the physical fitness were greatest in the explosive strength of upper (p ≤ 0.01, η(p)(2) = 0.09) and lower limbs (p ≤ 0.01, η(p)(2) = 0.08), although with a medium-size effect of gender, and smaller in the abdominal (p > 0.05, η(p)(2) = 0.007) and upper limbs (p > 0.05, η(p)(2) = 0.003) muscular endurance, and trunk extensor strength and flexibility (p > 0.05, η(p)(2) = 0.001). The endomorphic (p ≤ 0.01, η(p)(2) = 0.26) in the girls, and the ectomorphic (p ≤ 0.01, η(p)(2) = 0.31) and mesomorphic (p ≤ 0.01, η(p)(2) = 0.26) in the boys, had the high-sized effect on the physical fitness. The physical activity in the girls, and the endomorphic and body fat in the boys, did not have a significant effect. These findings can help in the planning of activities that take into account the success and motivation of both boys and girls and thus increase levels of physical activity and physical fitness at school. However, in prepubescent children, one cannot neglect the influence of genetic determinism, observed from the morphoconstitutional point of view.

"Shrink-to-fit" superhydrophobicity: thermally-induced microscale wrinkling of thin hydrophobic multilayers fabricated on flexible shrink-wrap substrates.

PubMed

Manna, Uttam; Carter, Matthew C D; Lynn, David M

2013-06-11

An approach to the design of flexible superhydrophobic surfaces based on thermally induced wrinkling of thin, hydrophobic polymer multilayers on heat-shrinkable polymer films is reported. This approach exploits shrinking processes common to "heat-shrink" plastics, and can thus be used to create "shrink-to-fit" superhydrophobic coatings on complex surfaces, manipulate the dimensions and densities of patterned features, and promote heat-activated repair of full-thickness defects. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dynamics modelling and Hybrid Suppression Control of space robots performing cooperative object manipulation

NASA Astrophysics Data System (ADS)

Zarafshan, P.; Moosavian, S. Ali A.

2013-10-01

Dynamics modelling and control of multi-body space robotic systems composed of rigid and flexible elements is elaborated here. Control of such systems is highly complicated due to severe under-actuated condition caused by flexible elements, and an inherent uneven nonlinear dynamics. Therefore, developing a compact dynamics model with the requirement of limited computations is extremely useful for controller design, also to develop simulation studies in support of design improvement, and finally for practical implementations. In this paper, the Rigid-Flexible Interactive dynamics Modelling (RFIM) approach is introduced as a combination of Lagrange and Newton-Euler methods, in which the motion equations of rigid and flexible members are separately developed in an explicit closed form. These equations are then assembled and solved simultaneously at each time step by considering the mutual interaction and constraint forces. The proposed approach yields a compact model rather than common accumulation approach that leads to a massive set of equations in which the dynamics of flexible elements is united with the dynamics equations of rigid members. To reveal such merits of this new approach, a Hybrid Suppression Control (HSC) for a cooperative object manipulation task will be proposed, and applied to usual space systems. A Wheeled Mobile Robotic (WMR) system with flexible appendages as a typical space rover is considered which contains a rigid main body equipped with two manipulating arms and two flexible solar panels, and next a Space Free Flying Robotic system (SFFR) with flexible members is studied. Modelling verification of these complicated systems is vigorously performed using ANSYS and ADAMS programs, while the limited computations of RFIM approach provides an efficient tool for the proposed controller design. Furthermore, it will be shown that the vibrations of the flexible solar panels results in disturbing forces on the base which may produce undesirable errors and perturb the object manipulation task. So, it is shown that these effects can be significantly eliminated by the proposed Hybrid Suppression Control algorithm.

Association between selected physical fitness parameters and esthetic competence in contemporary dancers.

PubMed

Angioi, Manuela; Metsios, George S; Twitchett, Emily; Koutedakis, Yiannis; Wyon, Matthew

2009-01-01

The physical demands imposed on contemporary dancers by choreographers and performance schedules make their physical fitness just as important to them as skill development. Nevertheless, it remains to be confirmed which physical fitness components are associated with aesthetic competence. The aim of this study was to: 1. replicate and test a novel aesthetic competence tool for reliability, and 2. investigate the association between selected physical fitness components and aesthetic competence by using this new tool. Seventeen volunteers underwent a series of physical fitness tests (body composition, flexibility, muscular power and endurance, and aerobic capacity) and aesthetic competence assessments (seven individual criteria commonly used by selected dance companies). Inter-rater reliability of the aesthetic competence tool was very high (r = 0.96). There were significant correlations between the aesthetic competence score and jump ability and push-ups (r = 0.55 and r = 0.55, respectively). Stepwise backward multiple regression analysis revealed that the best predictor of aesthetic competence was push-ups (R(2) = 0.30, p = 0.03). Univariate analyses also revealed that the interaction of push-ups and jump ability improved the prediction power of aesthetic competence (R(2) = 0.44, p = 0.004). It is concluded that upper body muscular endurance and jump ability best predict aesthetic competence of the present sample of contemporary dancers. Further research is required to investigate the contribution of other components of aesthetic competence, including upper body strength, lower body muscular endurance, general coordination, and static and dynamic balance.

Solar array deployment from a spinning spacecraft

NASA Technical Reports Server (NTRS)

Carlin, A. H.; Gardner, J. B.; Lassen, H. A.

1974-01-01

Cylindrical drum, wrapped with flexible solar array of solar cells mounted on Mylar sheet, is held by two end-fittings with cable (under tension) passing through axel of drum. Drum is held to end-fittings by axial cable through drum axel; drum is released for deployment when cable is cut at each end and end-fittings spring outward.

46 CFR 58.30-20 - Fluid power hose and fittings.

Code of Federal Regulations, 2012 CFR

2012-10-01

... MACHINERY AND RELATED SYSTEMS Fluid Power and Control Systems § 58.30-20 Fluid power hose and fittings. (a... 46 Shipping 2 2012-10-01 2012-10-01 false Fluid power hose and fittings. 58.30-20 Section 58.30-20... of flexible hose where required for proper operation of machinery and components in the hydraulic...

46 CFR 58.30-20 - Fluid power hose and fittings.

Code of Federal Regulations, 2011 CFR

2011-10-01

... MACHINERY AND RELATED SYSTEMS Fluid Power and Control Systems § 58.30-20 Fluid power hose and fittings. (a... 46 Shipping 2 2011-10-01 2011-10-01 false Fluid power hose and fittings. 58.30-20 Section 58.30-20... of flexible hose where required for proper operation of machinery and components in the hydraulic...

46 CFR 58.30-20 - Fluid power hose and fittings.

Code of Federal Regulations, 2013 CFR

2013-10-01

... MACHINERY AND RELATED SYSTEMS Fluid Power and Control Systems § 58.30-20 Fluid power hose and fittings. (a... 46 Shipping 2 2013-10-01 2013-10-01 false Fluid power hose and fittings. 58.30-20 Section 58.30-20... of flexible hose where required for proper operation of machinery and components in the hydraulic...

Fitness Level and Gross Motor Performance of Children with Attention-Deficit Hyperactivity Disorder

ERIC Educational Resources Information Center

Verret, Claudia; Gardiner, Phillip; Beliveau, Louise

2010-01-01

The purpose of this study was to assess fitness and gross motor performance of children with ADHD, including users and nonusers of methylphenidate medication. Seventy boys took part in the study. Fitness level of children with ADHD using medication or not, including body composition, flexibility, and muscular endurance, was similar to that of a…

A stochastic fractional dynamics model of space-time variability of rain

NASA Astrophysics Data System (ADS)

Kundu, Prasun K.; Travis, James E.

2013-09-01

varies in space and time in a highly irregular manner and is described naturally in terms of a stochastic process. A characteristic feature of rainfall statistics is that they depend strongly on the space-time scales over which rain data are averaged. A spectral model of precipitation has been developed based on a stochastic differential equation of fractional order for the point rain rate, which allows a concise description of the second moment statistics of rain at any prescribed space-time averaging scale. The model is thus capable of providing a unified description of the statistics of both radar and rain gauge data. The underlying dynamical equation can be expressed in terms of space-time derivatives of fractional orders that are adjusted together with other model parameters to fit the data. The form of the resulting spectrum gives the model adequate flexibility to capture the subtle interplay between the spatial and temporal scales of variability of rain but strongly constrains the predicted statistical behavior as a function of the averaging length and time scales. We test the model with radar and gauge data collected contemporaneously at the NASA TRMM ground validation sites located near Melbourne, Florida and on the Kwajalein Atoll, Marshall Islands in the tropical Pacific. We estimate the parameters by tuning them to fit the second moment statistics of radar data at the smaller spatiotemporal scales. The model predictions are then found to fit the second moment statistics of the gauge data reasonably well at these scales without any further adjustment.

Measuring organizational flexibility in community pharmacy: Building the capacity to implement cognitive pharmaceutical services.

PubMed

Feletto, Eleonora; Wilson, Laura Kate; Roberts, Alison Sarah; Benrimoj, Shalom Isaac

2011-03-01

Community pharmacy is undergoing transformation with increasing pressure to build its capacity to deliver cognitive pharmaceutical services ("services"). The theoretical framework of organizational flexibility (OF) may be used to assess the capacity of community pharmacy to implement change programs and guide capacity-building initiatives. To test the applicability of an existing scale measuring OF to the industry of community pharmacy in Australia. A mail survey was used to test a preexisting scale measuring OF amended from 28 items to 20 items testing 3 underlying factors of operational, structural, and strategic flexibility in the Australian community pharmacy context. The sample was 2006 randomly-stratified community pharmacies. A confirmatory factor analysis was conducted to assess the validity and reliability of the 1-factor models for each underlying construct and the full measurement model. Responses were received from a total of 395 (19.7%) community pharmacies. The 1-factor models of operational, structural, and strategic flexibility fit the data with appropriate respecification. Overall, the favorable fit of the individual factor constructs suggested that the multiple-factor measurement model should be tested. However, this model did not yield an interpretable response. Operational flexibility covaried negatively to the other factors, whereas structural and strategic flexibility shared covariance. Despite this, the results highlighting the individual factor fit suggest the constructs have application to pharmacy. The individual OF constructs were useful in the development and initial testing of a scale adapted for community pharmacy. When further developed and validated, the scale could be used to identify group of pharmacies that require individualized assistance to build capacity and integrate services and other new endeavors. Copyright © 2011 Elsevier Inc. All rights reserved.

Gender consistency and flexibility: using dynamics to understand the relationship between gender and adjustment.

PubMed

DiDonato, Matthew D; Martin, Carol L; Hessler, Eric E; Amazeen, Polemnia G; Hanish, Laura D; Fabes, Richard A

2012-04-01

Controversy surrounds questions regarding the influence of being gender consistent (i.e., having and expressing gendered characteristics that are consistent with one's biological sex) versus being gender flexible (i.e., having and expressing gendered characteristics that vary from masculine to feminine as circumstances arise) on children's adjustment outcomes, such as self-esteem, positive emotion, or behavior problems. Whereas evidence supporting the consistency hypothesis is abundant, little support exists for the flexibility hypothesis. To shed new light on the flexibility hypothesis, we explored children's gendered behavior from a dynamical perspective that highlighted variability and flexibility in addition to employing a conventional approach that emphasized stability and consistency. Conventional mean-level analyses supported the consistency hypothesis by revealing that gender atypical behavior was related to greater maladjustment, and dynamical analyses supported the flexibility hypothesis by showing that flexibility of gendered behavior over time was related to positive adjustment. Integrated analyses showed that gender typical behavior was related to the adjustment of children who were behaviorally inflexible, but not for those who were flexible. These results provided a more comprehensive understanding of the relation between gendered behavior and adjustment in young children and illustrated for the first time the feasibility of applying dynamical analyses to the study of gendered behavior.

A Computational Algorithm for Functional Clustering of Proteome Dynamics During Development

PubMed Central

Wang, Yaqun; Wang, Ningtao; Hao, Han; Guo, Yunqian; Zhen, Yan; Shi, Jisen; Wu, Rongling

2014-01-01

Phenotypic traits, such as seed development, are a consequence of complex biochemical interactions among genes, proteins and metabolites, but the underlying mechanisms that operate in a coordinated and sequential manner remain elusive. Here, we address this issue by developing a computational algorithm to monitor proteome changes during the course of trait development. The algorithm is built within the mixture-model framework in which each mixture component is modeled by a specific group of proteins that display a similar temporal pattern of expression in trait development. A nonparametric approach based on Legendre orthogonal polynomials was used to fit dynamic changes of protein expression, increasing the power and flexibility of protein clustering. By analyzing a dataset of proteomic dynamics during early embryogenesis of the Chinese fir, the algorithm has successfully identified several distinct types of proteins that coordinate with each other to determine seed development in this forest tree commercially and environmentally important to China. The algorithm will find its immediate applications for the characterization of mechanistic underpinnings for any other biological processes in which protein abundance plays a key role. PMID:24955031

Space robot simulator vehicle

NASA Technical Reports Server (NTRS)

Cannon, R. H., Jr.; Alexander, H.

1985-01-01

A Space Robot Simulator Vehicle (SRSV) was constructed to model a free-flying robot capable of doing construction, manipulation and repair work in space. The SRSV is intended as a test bed for development of dynamic and static control methods for space robots. The vehicle is built around a two-foot-diameter air-cushion vehicle that carries batteries, power supplies, gas tanks, computer, reaction jets and radio equipment. It is fitted with one or two two-link manipulators, which may be of many possible designs, including flexible-link versions. Both the vehicle body and its first arm are nearly complete. Inverse dynamic control of the robot's manipulator has been successfully simulated using equations generated by the dynamic simulation package SDEXACT. In this mode, the position of the manipulator tip is controlled not by fixing the vehicle base through thruster operation, but by controlling the manipulator joint torques to achieve the desired tip motion, while allowing for the free motion of the vehicle base. One of the primary goals is to minimize use of the thrusters in favor of intelligent control of the manipulator. Ways to reduce the computational burden of control are described.

Molecular dynamics study of the phosphorylation effect on the conformational states of the C-terminal domain of RNA polymerase II.

PubMed

Yonezawa, Yasushige

2014-05-01

The carboxyl-terminal domain (CTD) of RNA polymerase II in eukaryotes regulates mRNA processing processes by recruiting various regulation factors. A main function of the CTD relies on the heptad consensus sequence (YSPTSPS). The CTD dynamically changes its conformational state to recognize and bind different regulation factors. The dynamical conformation changes are caused by modifications, mainly phosphorylation and dephosphorylation, to the serine residues. In this study, we investigate the conformational states of the unit consensus CTD peptide with various phosphorylation patterns of the serine residues by extended ensemble simulations. The results show that the CTD without phosphorylation has a flexible disordered structure distributed between twisted and extended states, but phosphorylation tends to reduce the conformational space. It was found that phosphorylation induces a β-turn around the phosphorylated serine residue and the cis conformation of the proline residue significantly inhibits the β-turn formation. The β-turn should contribute to specific CTD binding of the different regulation factors by changing the conformation propensity combined with induced fit.

Molecular dynamics-based refinement and validation for sub-5 Å cryo-electron microscopy maps

PubMed Central

Singharoy, Abhishek; Teo, Ivan; McGreevy, Ryan; Stone, John E; Zhao, Jianhua; Schulten, Klaus

2016-01-01

Two structure determination methods, based on the molecular dynamics flexible fitting (MDFF) paradigm, are presented that resolve sub-5 Å cryo-electron microscopy (EM) maps with either single structures or ensembles of such structures. The methods, denoted cascade MDFF and resolution exchange MDFF, sequentially re-refine a search model against a series of maps of progressively higher resolutions, which ends with the original experimental resolution. Application of sequential re-refinement enables MDFF to achieve a radius of convergence of ~25 Å demonstrated with the accurate modeling of β-galactosidase and TRPV1 proteins at 3.2 Å and 3.4 Å resolution, respectively. The MDFF refinements uniquely offer map-model validation and B-factor determination criteria based on the inherent dynamics of the macromolecules studied, captured by means of local root mean square fluctuations. The MDFF tools described are available to researchers through an easy-to-use and cost-effective cloud computing resource on Amazon Web Services. DOI: http://dx.doi.org/10.7554/eLife.16105.001 PMID:27383269

Conformational Dynamics inside Amino-Terminal Disease Hotspot of Ryanodine Receptor

PubMed Central

Zhong, Xiaowei; Liu, Ying; Zhu, Li; Meng, Xing; Wang, Ruiwu; Van Petegem, Filip; Wagenknecht, Terence; Wayne Chen, S. R.; Liu, Zheng

2013-01-01

Summary The N-terminal region of both skeletal and cardiac ryanodine receptor is a disease mutation hotspot. Recently, a crystal structure of the RyR1 fragment (residues 1-559) was solved. This N-terminal structure contains three separate domains, A, B, and C, and was docked into a central vestibule in a full-length RyR1 cryo-EM map. Here we reconstructed 3D cryo-EM structures of two GFP-tagged RyR2s with GFP inserted after residue Glu-310 and Ser-437, respectively. The structures of RyR2E310-GFP and RyR2S437-GFP displayed an extra mass on domain B and C, directly validating the predicted docking model. Next, we revealed domain movements in molecular dynamics flexible fitting models in both the closed and open state cryo-EM maps. To further probe the conformational changes, we generated FRET pairs by inserting CFP or YFP in two selected domains, FRET studies of three dual-insertion pairs and three co-expressed single-insertion pairs showed the dynamic structural changes within the N-terminal domains. PMID:24139989

A special case of reduced rank models for identification and modelling of time varying effects in survival analysis.

PubMed

Perperoglou, Aris

2016-12-10

Flexible survival models are in need when modelling data from long term follow-up studies. In many cases, the assumption of proportionality imposed by a Cox model will not be valid. Instead, a model that can identify time varying effects of fixed covariates can be used. Although there are several approaches that deal with this problem, it is not always straightforward how to choose which covariates should be modelled having time varying effects and which not. At the same time, it is up to the researcher to define appropriate time functions that describe the dynamic pattern of the effects. In this work, we suggest a model that can deal with both fixed and time varying effects and uses simple hypotheses tests to distinguish which covariates do have dynamic effects. The model is an extension of the parsimonious reduced rank model of rank 1. As such, the number of parameters is kept low, and thus, a flexible set of time functions, such as b-splines, can be used. The basic theory is illustrated along with an efficient fitting algorithm. The proposed method is applied to a dataset of breast cancer patients and compared with a multivariate fractional polynomials approach for modelling time-varying effects. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Across the continuum of satisfaction with work-family balance: Work hours, flexibility-fit, and work-family culture.

PubMed

McNamara, Tay K; Pitt-Catsouphes, Marcie; Matz-Costa, Christina; Brown, Melissa; Valcour, Monique

2013-03-01

This study investigated the association between hours worked per week and satisfaction with work-family balance, using data from a 2007-2008 survey of employees nested within organizations. We tested hypotheses informed by the resource drain and resources-and-demands perspectives using quantile regression. We found that the negative association between hours worked per week and satisfaction with work-family balance was significantly stronger at the 25th percentile, as compared to at the 75th percentile, of satisfaction with work-family balance. Further, there was some evidence that perceived flexibility-fit (i.e., the fit between worker needs and flexible work options available) and supportive work-family culture attenuated the relationship between hours worked and satisfaction with work-family balance. The results suggest that analyses focusing on the average relationship between long work hours (such as those using ordinary least squares regression) and satisfaction with work-family balance may underestimate the importance of long work hours for workers with lower satisfaction levels. Copyright © 2012 Elsevier Inc. All rights reserved.

Note: Design and capability verification of fillet triangle flexible support

NASA Astrophysics Data System (ADS)

Wang, Tao; San, Xiao-Gang; Gao, Shi-Jie; Wang, Jing; Ni, Ying-Xue; Sang, Zhi-Xin

2017-12-01

By increasing the section thickness of a triangular flexible hinge, this study focuses on optimal selection of parameters of fillet triangle flexible hinges and flexible support. Based on Castigliano's second theorem, the flexibility expression of the fillet triangle flexible hinge was derived. Then, the case design is performed, and the comparison of three types of flexible hinges with this type of flexible hinge was carried out. The finite element models of fillet triangle flexible hinges and flexible support were built, and then the simulation results of performance parameters were calculated. Finally, the experiment platform was established to validate analysis results. The maximum error is less than 8%, which verifies the accuracy of the simulation process and equations derived; also the fundamental frequency fits the requirements of the system. The fillet triangle flexible hinge is proved to have the advantages of high precision and low flexibility.

Note: Design and capability verification of fillet triangle flexible support.

PubMed

Wang, Tao; San, Xiao-Gang; Gao, Shi-Jie; Wang, Jing; Ni, Ying-Xue; Sang, Zhi-Xin

2017-12-01

By increasing the section thickness of a triangular flexible hinge, this study focuses on optimal selection of parameters of fillet triangle flexible hinges and flexible support. Based on Castigliano's second theorem, the flexibility expression of the fillet triangle flexible hinge was derived. Then, the case design is performed, and the comparison of three types of flexible hinges with this type of flexible hinge was carried out. The finite element models of fillet triangle flexible hinges and flexible support were built, and then the simulation results of performance parameters were calculated. Finally, the experiment platform was established to validate analysis results. The maximum error is less than 8%, which verifies the accuracy of the simulation process and equations derived; also the fundamental frequency fits the requirements of the system. The fillet triangle flexible hinge is proved to have the advantages of high precision and low flexibility.

Hydrokinesitherapy program using the Halliwick method on strength endurance and flexibility in a person with poliomyelitis sequelae.

PubMed

Ochoa Martínez, Paulina Yesica; Hall Lopez, Javier Arturo; Mateos Valenzuela, Adriana Griselda

2014-09-12

This case study attempts to determine the effect of a hydrokinesitherapy program by means of the Halliwick method on physical fitness in a female aged 35 years with poliomyelitis sequelae. The intervention followed sixteen weeks of hydrokinesitherapy during 70 minutes, five times a week, where we carried out exercises from the Halliwick method. There was an assessment both before and after the application. Strength endurance and flexibility were determined according to a senior fitness test protocol. The results showed positive improvements when carrying out the exercises from the Halliwick method and the percentage change (Δ%) of strength endurance increase 361.5% in the right arm and 300% in the left arm. Flexibility increased 2 cm in the right shoulder and 10 cm in the left shoulder. In conclusion the subject was able to improve the performance of Halliwick exercises while showing an increase in strength endurance and flexibility. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

On the Move with the Waukesha Walkers.

ERIC Educational Resources Information Center

Gissal, Mary L.; Ray, Robert O.

1981-01-01

As part of a research study, a fitness trail was designed for older adults to increase their physical fitness and cardiovascular health. Exercise stations placed at quarter-mile intervals introduced exercises effective in improving flexibility, muscular strength, endurance, balance, and coordination. (JN)

Detecting similarities among distant homologous proteins by comparison of domain flexibilities.

PubMed

Pandini, Alessandro; Mauri, Giancarlo; Bordogna, Annalisa; Bonati, Laura

2007-06-01

Aim of this work is to assess the informativeness of protein dynamics in the detection of similarities among distant homologous proteins. To this end, an approach to perform large-scale comparisons of protein domain flexibilities is proposed. CONCOORD is confirmed as a reliable method for fast conformational sampling. The root mean square fluctuation of alpha carbon positions in the essential dynamics subspace is employed as a measure of local flexibility and a synthetic index of similarity is presented. The dynamics of a large collection of protein domains from ASTRAL/SCOP40 is analyzed and the possibility to identify relationships, at both the family and the superfamily levels, on the basis of the dynamical features is discussed. The obtained picture is in agreement with the SCOP classification, and furthermore suggests the presence of a distinguishable familiar trend in the flexibility profiles. The results support the complementarity of the dynamical and the structural information, suggesting that information from dynamics analysis can arise from functional similarities, often partially hidden by a static comparison. On the basis of this first test, flexibility annotation can be expected to help in automatically detecting functional similarities otherwise unrecoverable.

Modified Dynamic Inversion to Control Large Flexible Aircraft: What's Going On?

NASA Technical Reports Server (NTRS)

Gregory, Irene M.

1999-01-01

High performance aircraft of the future will be designed lighter, more maneuverable, and operate over an ever expanding flight envelope. One of the largest differences from the flight control perspective between current and future advanced aircraft is elasticity. Over the last decade, dynamic inversion methodology has gained considerable popularity in application to highly maneuverable fighter aircraft, which were treated as rigid vehicles. This paper explores dynamic inversion application to an advanced highly flexible aircraft. An initial application has been made to a large flexible supersonic aircraft. In the course of controller design for this advanced vehicle, modifications were made to the standard dynamic inversion methodology. The results of this application were deemed rather promising. An analytical study has been undertaken to better understand the nature of the made modifications and to determine its general applicability. This paper presents the results of this initial analytical look at the modifications to dynamic inversion to control large flexible aircraft.

Kansas Adapted/Special Physical Education Test Manual. Health Related Fitness and Psychomotor Testing.

ERIC Educational Resources Information Center

Johnson, Robert E.; Lavay, Barry

This manual was developed to address the need for health-related physical fitness testing of children with special needs. The first section defines the components of health-related physical fitness which consist of: (1)abdominal strength and endurance measured by a sit-up test; (2) flexibility, measured by a sit and reach test; (3) upper body…

Controlling flexible structures with second order actuator dynamics

NASA Technical Reports Server (NTRS)

Inman, Daniel J.; Umland, Jeffrey W.; Bellos, John

1989-01-01

The control of flexible structures for those systems with actuators that are modeled by second order dynamics is examined. Two modeling approaches are investigated. First a stability and performance analysis is performed using a low order finite dimensional model of the structure. Secondly, a continuum model of the flexible structure to be controlled, coupled with lumped parameter second order dynamic models of the actuators performing the control is used. This model is appropriate in the modeling of the control of a flexible panel by proof-mass actuators as well as other beam, plate and shell like structural numbers. The model is verified with experimental measurements.

Adjustable mounting device for high-volume production of beam-shaping systems for high-power diode lasers

NASA Astrophysics Data System (ADS)

Haag, Sebastian; Bernhardt, Henning; Rübenach, Olaf; Haverkamp, Tobias; Müller, Tobias; Zontar, Daniel; Brecher, Christian

2015-02-01

In many applications for high-power diode lasers, the production of beam-shaping and homogenizing optical systems experience rising volumes and dynamical market demands. The automation of assembly processes on flexible and reconfigurable machines can contribute to a more responsive and scalable production. The paper presents a flexible mounting device designed for the challenging assembly of side-tab based optical systems. It provides design elements for precisely referencing and fixating two optical elements in a well-defined geometric relation. Side tabs are presented to the machine allowing the application of glue and a rotating mechanism allows the attachment to the optical elements. The device can be adjusted to fit different form factors and it can be used in high-volume assembly machines. The paper shows the utilization of the device for a collimation module consisting of a fast-axis and a slow-axis collimation lens. Results regarding the repeatability and process capability of bonding side tab assemblies as well as estimates from 3D simulation for overall performance indicators achieved such as cycle time and throughput will be discussed.

Self-organising mixture autoregressive model for non-stationary time series modelling.

PubMed

Ni, He; Yin, Hujun

2008-12-01

Modelling non-stationary time series has been a difficult task for both parametric and nonparametric methods. One promising solution is to combine the flexibility of nonparametric models with the simplicity of parametric models. In this paper, the self-organising mixture autoregressive (SOMAR) network is adopted as a such mixture model. It breaks time series into underlying segments and at the same time fits local linear regressive models to the clusters of segments. In such a way, a global non-stationary time series is represented by a dynamic set of local linear regressive models. Neural gas is used for a more flexible structure of the mixture model. Furthermore, a new similarity measure has been introduced in the self-organising network to better quantify the similarity of time series segments. The network can be used naturally in modelling and forecasting non-stationary time series. Experiments on artificial, benchmark time series (e.g. Mackey-Glass) and real-world data (e.g. numbers of sunspots and Forex rates) are presented and the results show that the proposed SOMAR network is effective and superior to other similar approaches.

Modal resonant dynamics of cables with a flexible support: A modulated diffraction problem

NASA Astrophysics Data System (ADS)

Guo, Tieding; Kang, Houjun; Wang, Lianhua; Liu, Qijian; Zhao, Yueyu

2018-06-01

Modal resonant dynamics of cables with a flexible support is defined as a modulated (wave) diffraction problem, and investigated by asymptotic expansions of the cable-support coupled system. The support-cable mass ratio, which is usually very large, turns out to be the key parameter for characterizing cable-support dynamic interactions. By treating the mass ratio's inverse as a small perturbation parameter and scaling the cable tension properly, both cable's modal resonant dynamics and the flexible support dynamics are asymptotically reduced by using multiple scale expansions, leading finally to a reduced cable-support coupled model (i.e., on a slow time scale). After numerical validations of the reduced coupled model, cable-support coupled responses and the flexible support induced coupling effects on the cable, are both fully investigated, based upon the reduced model. More explicitly, the dynamic effects on the cable's nonlinear frequency and force responses, caused by the support-cable mass ratio, the resonant detuning parameter and the support damping, are carefully evaluated.

Independent Metrics for Protein Backbone and Side-Chain Flexibility: Time Scales and Effects of Ligand Binding.

PubMed

Fuchs, Julian E; Waldner, Birgit J; Huber, Roland G; von Grafenstein, Susanne; Kramer, Christian; Liedl, Klaus R

2015-03-10

Conformational dynamics are central for understanding biomolecular structure and function, since biological macromolecules are inherently flexible at room temperature and in solution. Computational methods are nowadays capable of providing valuable information on the conformational ensembles of biomolecules. However, analysis tools and intuitive metrics that capture dynamic information from in silico generated structural ensembles are limited. In standard work-flows, flexibility in a conformational ensemble is represented through residue-wise root-mean-square fluctuations or B-factors following a global alignment. Consequently, these approaches relying on global alignments discard valuable information on local dynamics. Results inherently depend on global flexibility, residue size, and connectivity. In this study we present a novel approach for capturing positional fluctuations based on multiple local alignments instead of one single global alignment. The method captures local dynamics within a structural ensemble independent of residue type by splitting individual local and global degrees of freedom of protein backbone and side-chains. Dependence on residue type and size in the side-chains is removed via normalization with the B-factors of the isolated residue. As a test case, we demonstrate its application to a molecular dynamics simulation of bovine pancreatic trypsin inhibitor (BPTI) on the millisecond time scale. This allows for illustrating different time scales of backbone and side-chain flexibility. Additionally, we demonstrate the effects of ligand binding on side-chain flexibility of three serine proteases. We expect our new methodology for quantifying local flexibility to be helpful in unraveling local changes in biomolecular dynamics.

Let's Get Fit!: Fitness Activities for Children with Severe/Profound Disabilities.

ERIC Educational Resources Information Center

Modell, Scott J.; Cox, Thomas Alan

1999-01-01

Guidelines for developing a physical activity program for students with severe/profound disabilities address medical clearance; levels of participation; staffing; equipment; and program components, including warm-up, range of motion/flexibility activities, aerobics, resistance training, and cool-down. (DB)

Examinations of tRNA Range of Motion Using Simulations of Cryo-EM Microscopy and X-Ray Data.

PubMed

Caulfield, Thomas R; Devkota, Batsal; Rollins, Geoffrey C

2011-01-01

We examined tRNA flexibility using a combination of steered and unbiased molecular dynamics simulations. Using Maxwell's demon algorithm, molecular dynamics was used to steer X-ray structure data toward that from an alternative state obtained from cryogenic-electron microscopy density maps. Thus, we were able to fit X-ray structures of tRNA onto cryogenic-electron microscopy density maps for hybrid states of tRNA. Additionally, we employed both Maxwell's demon molecular dynamics simulations and unbiased simulation methods to identify possible ribosome-tRNA contact areas where the ribosome may discriminate tRNAs during translation. Herein, we collected >500 ns of simulation data to assess the global range of motion for tRNAs. Biased simulations can be used to steer between known conformational stop points, while unbiased simulations allow for a general testing of conformational space previously unexplored. The unbiased molecular dynamics data describes the global conformational changes of tRNA on a sub-microsecond time scale for comparison with steered data. Additionally, the unbiased molecular dynamics data was used to identify putative contacts between tRNA and the ribosome during the accommodation step of translation. We found that the primary contact regions were H71 and H92 of the 50S subunit and ribosomal proteins L14 and L16.

Relationship between sports experience and executive function in 6-12-year-old children: independence from physical fitness and moderation by gender.

PubMed

Ishihara, Toru; Sugasawa, Shigemi; Matsuda, Yusuke; Mizuno, Masao

2018-05-01

The purpose of this study was to evaluate the relationship between sports experience (i.e., tennis experience) and executive function in children while controlling for physical activity and physical fitness. Sixty-eight participants (6-12 years old, 34 males and 34 females) were enrolled in regular tennis lessons (mean = 2.4 years, range = 0.1-7.3 years) prior to the study. Executive functions, including inhibitory control (the Stroop Color-Word Test), working memory (the 2-back Task), and cognitive flexibility (the Local-global Task) were evaluated. Participants' levels of daily physical activity, ranging from moderate to vigorous, were evaluated using triaxial accelerometers. The total score for physical fitness was assessed using the Tennis Field Test. Hierarchical multiple regression analyses revealed interaction effects between gender and tennis experience on participants' reaction time (RT) on the switch cost of the Local-global Task after controlling for age, BMI, gender, physical activity, physical fitness, and tennis experience. Longer tennis experience was associated with shorter switch cost in males but not in females. Higher scores on physical fitness were positively associated with lower interference scores on the Stroop Color-Word Test, RT on the 2-back Task, and RT in the switching condition of the Local-global Task, after controlling for age, BMI, gender, and physical activity. In conclusion, all three foundational components of executive function (i.e., inhibitory control, working memory, and cognitive flexibility) were more strongly related to physical fitness than to physical activity in males and females, whereas greater cognitive flexibility was related to tennis experience only in the males. © 2017 John Wiley & Sons Ltd.

Computational methods for the identification of spatially varying stiffness and damping in beams

NASA Technical Reports Server (NTRS)

Banks, H. T.; Rosen, I. G.

1986-01-01

A numerical approximation scheme for the estimation of functional parameters in Euler-Bernoulli models for the transverse vibration of flexible beams with tip bodies is developed. The method permits the identification of spatially varying flexural stiffness and Voigt-Kelvin viscoelastic damping coefficients which appear in the hybrid system of ordinary and partial differential equations and boundary conditions describing the dynamics of such structures. An inverse problem is formulated as a least squares fit to data subject to constraints in the form of a vector system of abstract first order evolution equations. Spline-based finite element approximations are used to finite dimensionalize the problem. Theoretical convergence results are given and numerical studies carried out on both conventional (serial) and vector computers are discussed.

Physical Fitness in the Army

DTIC Science & Technology

1977-03-17

in fitness as the absence of disease or injury . The coach defines fitness as §l’Jse factors responsible for success in a sport. The leader is...lower back and legs to gradually increase your body’s level of activity. This will reduce the risk of injury and prevent unnecessary soreness. Also, a...flexibility. Let’s discuss the importance of muscular fitness and how we can achieve this kind of fitneas through weightlifting or calisthenics. Remember

Identification of dynamic characteristics of flexible rotors as dynamic inverse problem

NASA Technical Reports Server (NTRS)

Roisman, W. P.; Vajingortin, L. D.

1991-01-01

The problem of dynamic and balancing of flexible rotors were considered, which were set and solved as the problem of the identification of flexible rotor systems, which is the same as the inverse problem of the oscillation theory dealing with the task of the identifying the outside influences and system parameters on the basis of the known laws of motion. This approach to the problem allows the disclosure the picture of disbalances throughout the rotor-under-test (which traditional methods of flexible rotor balancing, based on natural oscillations, could not provide), and identify dynamic characteristics of the system, which correspond to a selected mathematical model. Eventually, various methods of balancing were developed depending on the special features of the machines as to their design, technology, and operation specifications. Also, theoretical and practical methods are given for the flexible rotor balancing at far from critical rotation frequencies, which does not necessarily require the knowledge forms of oscillation, dissipation, and elasticity and inertia characteristics, and to use testing masses.

Functional fitness norms for community-dwelling older adults in Hong Kong.

PubMed

Chung, Pak-Kwong; Zhao, Yanan; Liu, Jing-Dong; Quach, Binh

2016-01-01

This study aimed to establish normative data for older adults in Hong Kong and explore age and sex differences in functional fitness. A sample of 944 independent community-dwellers, aged 65-74 years, was evaluated using the Senior Fitness Test battery in addition to hand grip and single leg stance tests. Normative data were reported for the 10th, 25th, 50th, 75th, and 90th percentiles in 5-year age groups. Except for upper extremity muscle strength in women and body mass index (BMI) in both sexes, ageing-associated degradation was observed in all testing parameters especially in flexibility, balance, and agility. Significant sex differences were found in all testing parameters with the exception of BMI and static balance with eyes open. Moreover, men demonstrated higher capacities for muscle strength, agility, balance, and aerobic endurance, whereas women showed superior flexibility. The normative values enable the evaluation of individual performance regarding the fitness status of older adults in Hong Kong. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Improving the fitness and physical activity levels of primary school children: results of the Fit-4-Fun group randomized controlled trial.

PubMed

Eather, Narelle; Morgan, Philip J; Lubans, David R

2013-01-01

To evaluate the impact of a multi-component school-based physical activity intervention (Fit-4-Fun) on health-related fitness and objectively measured physical activity in primary school children. Four Hunter primary schools were recruited in April, 2011 and randomized by school into treatment or control conditions. Participants included 213 children (mean age = 10.72 years ± 0.6; 52.2% female) with the treatment group (n = 118) completing the 8-week Fit-4-Fun Program. Participants were assessed at baseline and 6-month follow-up, with a 91% retention rate. Cardio-respiratory fitness (CRF) (20 m shuttle run) was the primary outcome, and secondary outcomes included body composition (BMI, BMI(Z)), muscular fitness (7-stage sit-up test, push-up test, basketball throw test, Standing Jump), flexibility (sit and reach) and physical activity (7 days pedometry). After 6-months, significant treatment effects were found for CRF (adjusted mean difference, 1.14 levels, p < 0.001), body composition (BMI mean, -0.96 kg/m(2), p < 0.001 and BMI z-score mean -0.47 z-scores, p < 0.001), flexibility (sit and reach mean, 1.52 cm, p = 0.0013), muscular fitness (sit-ups) (mean 0.62 stages, p = 0.003) and physical activity (mean, 3253 steps/day, p < 0.001). There were no group by time effects for the other muscular fitness measures. A primary school-based intervention focusing on fitness education significantly improved health-related fitness and physical activity levels in children. Copyright © 2012 Elsevier Inc. All rights reserved.

The effect of lifestyle modification on physical fitness and work ability in different workstyles.

PubMed

Ohta, Masanori; Okufuji, Tatsuya; Matsushima, Yasuyuki; Ikeda, Masaharu

2004-12-01

It is generally considered that physical fitness is affected by daily life activities including leisure time activity and working time activity. The aim of this study is to investigate the effects of different levels of physical activity at work on physical fitness, analyze the effects of 12-week lifestyle modification outside of working hours on physical fitness, work satisfaction and subjective symptoms, and to consider the role of lifestyle modification in occupational health. Lifestyle modification, consisting of aerobic exercise and diet counseling, was conducted for 12 weeks. The data before and after the intervention from 49 male workers were obtained. Physical fitness such as exercise endurance, flexibility, agility, balance, muscular strength, muscular endurance, and muscular power was measured before and after the intervention. The subjects were asked to fill out questionnaires about their work activities, subjective complaints, and work satisfaction. Subjects were divided into active work group (n = 14) and sedentary work group (n = 35) for analysis according to their work activities. As for differences in physical fitness due to different levels of physical activity, the active work group had superior exercise endurance and balance compared to the sedentary work group. In addition, the sedentary work group tended to experience greater fatigue than the active work group. In the active work group, flexibility and muscular strength were significantly increased with lifestyle modification and, in the sedentary work group, exercise endurance, flexibility and muscular endurance were significantly improved while balance also showed a tendency to improve. In the sedentary work group, lifestyle modification resulted in reduced fatigue and stiff neck as well as an increased work satisfaction. In the active work group, no change was observed in complaints or work satisfaction, but improved physical fitness led to a reduction in subjective complaints and an increase in work satisfaction. The level of physical activity at work contributes to the physical fitness of the worker and the addition of aerobic exercise in the worker's leisure time improves physical fitness and thereby contributes to increased work ability regardless of differences in the level of physical activity at work.

Flexibility damps macromolecular crowding effects on protein folding dynamics: Application to the murine prion protein (121-231)

NASA Astrophysics Data System (ADS)

Bergasa-Caceres, Fernando; Rabitz, Herschel A.

2014-01-01

A model of protein folding kinetics is applied to study the combined effects of protein flexibility and macromolecular crowding on protein folding rate and stability. It is found that the increase in stability and folding rate promoted by macromolecular crowding is damped for proteins with highly flexible native structures. The model is applied to the folding dynamics of the murine prion protein (121-231). It is found that the high flexibility of the native isoform of the murine prion protein (121-231) reduces the effects of macromolecular crowding on its folding dynamics. The relevance of these findings for the pathogenic mechanism are discussed.

[PHYSICAL ACTIVITY LEVELS, PHYSICAL FITNESS AND SCREE TIME AMONG CHILDREN AND ADOLESCENTS FROM BOGOTÁ, COLOMBIA].

PubMed

Prieto-Benavides, Daniel Humberto; Correa-Bautista, Jorge Enrique; Ramírez-Vélez, Robinson

2015-11-01

to investigate the association between objective measures of physical activity levels, physical fitness and screen time in Colombia children and adolescents from Bogota, Colombia. a sample of 149 healthy Colombian youth, children and adolescents (9-17.9 years old) participated in the study. Physical activity level was assessed over 7 days using an accelerometer. Weight, height, waist circumference, hip waist, subscapular/ triceps skinfold thicknesses and self-reported screen time (television/internet and videogame-viewing time) were measured. Aerobic capacity, handgrip strength, standing broad jump, vertical jump, speed/agility and flexibility were used as indicators of physical fitness. in girls with a high level of physical activity had favorable aerobic capacity (r = 0.366) and inverse relationship with subscapular/triceps skinfold thicknesses (r = -0.257) and (r = -0,237) p < 0.05, respectively. In boys, vigorous physical activity were associated with higher values of flexibility (r = 0.277) and aerobic capacity (r = 0.347), p < 0.05. Finally, the participants who watched 2 h or less of television per day showed 1.81 times (95%CI 1.401 to 2.672) that met physical activity guidelines. the healthy Colombian youth who reported moderate to vigorous objective measures of physical activity levels, presented higher levels in physical fitness especially in aerobic capacity and flexibility and lower values in subscapular/triceps skinfold thicknesses. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

[Psychometric properties of the third version of family adaptability and cohesion evaluation scales (FACES-III): a study of peruvian adolescents].

PubMed

Bazo-Alvarez, Juan Carlos; Bazo-Alvarez, Oscar Alfredo; Aguila, Jeins; Peralta, Frank; Mormontoy, Wilfredo; Bennett, Ian M

2016-01-01

Our aim was to evaluate the psychometric properties of the FACES-III among Peruvian high school students. This is a psychometric cross-sectional study. A probabilistic sampling was applied, defined by three stages: stratum one (school), stratum two (grade) and cluster (section). The participants were 910 adolescent students of both sexes, between 11 and 18 years of age. The instrument was also the object of study: the Olson's FACES-III. The analysis included a review of the structure / construct validity of the measure by factor analysis and assessment of internal consistency (reliability). The real-cohesion scale had moderately high reliability (Ω=.85) while the real-flexibility scale had moderate reliability (Ω=.74). The reliability found for the ideal-cohesion was moderately high (Ω=.89) like for the scale of ideal-flexibility (Ω=.86). Construct validity was confirmed by the goodness of fit of a two factor model (cohesion and flexibility) with 10 items each [Adjusted goodness of fit index (AGFI) = 0.96; Expected Cross Validation Index (ECVI) = 0.87; Normed fit index (NFI) = 0.93; Goodness of fit index (GFI) = 0.97; Root mean square error of approximation (RMSEA) = 0.06]. FACES-III has sufficient reliability and validity to be used in Peruvian adolescents for the purpose of group or individual assessment.

A model of the dynamics of household vegetarian and vegan rates in the U.K.

PubMed

Waters, James

2018-08-01

Although there are many studies of determinants of vegetarianism and veganism, there have been no previous studies of how their rates in a population jointly change over time. In this paper, we present a flexible model of vegetarian and vegan dietary choices, and derive the joint dynamics of rates of consumption. We fit our model to a pseudo-panel with 23 years of U.K. household data, and find that while vegetarian rates are largely determined by current household characteristics, vegan rates are additionally influenced by their own lagged value. We solve for equilibrium rates of vegetarianism and veganism, show that rates of consumption return to their equilibrium levels following a temporary event which changes those rates, and estimate the effects of campaigns to promote non-meat diets. We find that a persistent vegetarian campaign has a significantly positive effect on the rate of vegan consumption, in answer to an active debate among vegan campaigners. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dynamic Behavior of Wind Turbine by a Mixed Flexible-Rigid Multi-Body Model

NASA Astrophysics Data System (ADS)

Wang, Jianhong; Qin, Datong; Ding, Yi

A mixed flexible-rigid multi-body model is presented to study the dynamic behavior of a horizontal axis wind turbine. The special attention is given to flexible body: flexible rotor is modeled by a newly developed blade finite element, support bearing elasticities, variations in the number of teeth in contact as well as contact tooth's elasticities are mainly flexible components in the power train. The couple conditions between different subsystems are established by constraint equations. The wind turbine model is generated by coupling models of rotor, power train and generator with constraint equations together. Based on this model, an eigenproblem analysis is carried out to show the mode shape of rotor and power train at a few natural frequencies. The dynamic responses and contact forces among gears under constant wind speed and fixed pitch angle are analyzed.

Dynamic modelling and adaptive robust tracking control of a space robot with two-link flexible manipulators under unknown disturbances

NASA Astrophysics Data System (ADS)

Yang, Xinxin; Ge, Shuzhi Sam; He, Wei

2018-04-01

In this paper, both the closed-form dynamics and adaptive robust tracking control of a space robot with two-link flexible manipulators under unknown disturbances are developed. The dynamic model of the system is described with assumed modes approach and Lagrangian method. The flexible manipulators are represented as Euler-Bernoulli beams. Based on singular perturbation technique, the displacements/joint angles and flexible modes are modelled as slow and fast variables, respectively. A sliding mode control is designed for trajectories tracking of the slow subsystem under unknown but bounded disturbances, and an adaptive sliding mode control is derived for slow subsystem under unknown slowly time-varying disturbances. An optimal linear quadratic regulator method is proposed for the fast subsystem to damp out the vibrations of the flexible manipulators. Theoretical analysis validates the stability of the proposed composite controller. Numerical simulation results demonstrate the performance of the closed-loop flexible space robot system.

Can conservation contracts co-exist with change? Payment for ecosystem services in the context of adaptive decision-making and sustainability.

PubMed

Hayes, Tanya; Murtinho, Felipe; Cárdenas Camacho, Luis Mario; Crespo, Patricio; McHugh, Sarah; Salmerón, David

2015-01-01

This paper considers the ability of payment for ecosystem services (PES) programs to operate in the context of dynamic and complex social-ecological systems. Drawing on the experiences of two different PES programs in Latin America, we examine how PES institutions fit with the tenets of adaptive decision-making for sustainable resource management. We identify how the program goals and the connection to the market influence the incentive structure, information gathering, learning and feedback processes, and the structure of decision-making rights, specifically the ability to make and modify resource-use rules. Although limited in their generalizability, findings from the two case studies suggest a tension between the contractual model of PES and adaptive decision-making in natural resource systems. PES programs are not inherently decentralized, flexible management tools, as PES contracts tend to restrict decision-making rights and offer minimal flexibility mechanisms to change resource-use practices over the duration of the contract period. Furthermore, PES design and flexibility is heavily dependent on the goals and mission of the buyer and the respective market. If PES is to facilitate sustainable resource management, greater attention is needed to assess how the institutional design of the PES contracts influence the motivation and capacity of participants and program officers alike to adaptively manage the respective resource systems.

Can Conservation Contracts Co-exist with Change? Payment for Ecosystem Services in the Context of Adaptive Decision-Making and Sustainability

NASA Astrophysics Data System (ADS)

Hayes, Tanya; Murtinho, Felipe; Cárdenas Camacho, Luis Mario; Crespo, Patricio; McHugh, Sarah; Salmerón, David

2015-01-01

This paper considers the ability of payment for ecosystem services (PES) programs to operate in the context of dynamic and complex social-ecological systems. Drawing on the experiences of two different PES programs in Latin America, we examine how PES institutions fit with the tenets of adaptive decision-making for sustainable resource management. We identify how the program goals and the connection to the market influence the incentive structure, information gathering, learning and feedback processes, and the structure of decision-making rights, specifically the ability to make and modify resource-use rules. Although limited in their generalizability, findings from the two case studies suggest a tension between the contractual model of PES and adaptive decision-making in natural resource systems. PES programs are not inherently decentralized, flexible management tools, as PES contracts tend to restrict decision-making rights and offer minimal flexibility mechanisms to change resource-use practices over the duration of the contract period. Furthermore, PES design and flexibility is heavily dependent on the goals and mission of the buyer and the respective market. If PES is to facilitate sustainable resource management, greater attention is needed to assess how the institutional design of the PES contracts influence the motivation and capacity of participants and program officers alike to adaptively manage the respective resource systems.

Simulation of the evolution of root water foraging strategies in dry and shallow soils.

PubMed

Renton, Michael; Poot, Pieter

2014-09-01

The dynamic structural development of plants can be seen as a strategy for exploiting the limited resources available within their environment, and we would expect that evolution would lead to efficient strategies that reduce costs while maximizing resource acquisition. In particular, perennial species endemic to habitats with shallow soils in seasonally dry environments have been shown to have a specialized root system morphology that may enhance access to water resources in the underlying rock. This study aimed to explore these hypotheses by applying evolutionary algorithms to a functional-structural root growth model. A simulation model of a plant's root system was developed, which represents the dynamics of water uptake and structural growth. The model is simple enough for evolutionary optimization to be computationally feasible, yet flexible enough to allow a range of structural development strategies to be explored. The model was combined with an evolutionary algorithm in order to investigate a case study habitat with a highly heterogeneous distribution of resources, both spatially and temporally--the situation of perennial plants occurring on shallow soils in seasonally dry environments. Evolution was simulated under two contrasting fitness criteria: (1) the ability to find wet cracks in underlying rock, and (2) maximizing above-ground biomass. The novel approach successfully resulted in the evolution of more efficient structural development strategies for both fitness criteria. Different rooting strategies evolved when different criteria were applied, and each evolved strategy made ecological sense in terms of the corresponding fitness criterion. Evolution selected for root system morphologies which matched those of real species from corresponding habitats. Specialized root morphology with deeper rather than shallower lateral branching enhances access to water resources in underlying rock. More generally, the approach provides insights into both evolutionary processes and ecological costs and benefits of different plant growth strategies.

Stress attenuates the flexible updating of aversive value

PubMed Central

Raio, Candace M.; Hartley, Catherine A.; Orederu, Temidayo A.; Li, Jian; Phelps, Elizabeth A.

2017-01-01

In a dynamic environment, sources of threat or safety can unexpectedly change, requiring the flexible updating of stimulus−outcome associations that promote adaptive behavior. However, aversive contexts in which we are required to update predictions of threat are often marked by stress. Acute stress is thought to reduce behavioral flexibility, yet its influence on the modulation of aversive value has not been well characterized. Given that stress exposure is a prominent risk factor for anxiety and trauma-related disorders marked by persistent, inflexible responses to threat, here we examined how acute stress affects the flexible updating of threat responses. Participants completed an aversive learning task, in which one stimulus was probabilistically associated with an electric shock, while the other stimulus signaled safety. A day later, participants underwent an acute stress or control manipulation before completing a reversal learning task during which the original stimulus−outcome contingencies switched. Skin conductance and neuroendocrine responses provided indices of sympathetic arousal and stress responses, respectively. Despite equivalent initial learning, stressed participants showed marked impairments in reversal learning relative to controls. Additionally, reversal learning deficits across participants were related to heightened levels of alpha-amylase, a marker of noradrenergic activity. Finally, fitting arousal data to a computational reinforcement learning model revealed that stress-induced reversal learning deficits emerged from stress-specific changes in the weight assigned to prediction error signals, disrupting the adaptive adjustment of learning rates. Our findings provide insight into how stress renders individuals less sensitive to changes in aversive reinforcement and have implications for understanding clinical conditions marked by stress-related psychopathology. PMID:28973957

Outcomes of Stay Strong, Stay Healthy in community settings.

PubMed

Ball, Stephen; Gammon, Robin; Kelly, Patricia J; Cheng, An-Lin; Chertoff, Keyna; Kaume, Lydia; Abreu, Eduardo L; Brotto, Marco

2013-12-01

Loss of muscle strength, flexibility, and balance are strong predictors of falls in the elderly. The goal of this research was to investigate the effectiveness of a 10-week, strength-based exercise program delivered by Extension professionals. Matched pair t tests were used to compare differences in five measures of fitness collected from 808 participants (mean age = 65.4 years) at the start and finish of the exercise program. Following programming, participants significantly improved strength, flexibility, and balance. Results indicate that an evidence-based program can be translated into a community Extension program that is able to improve the fitness level of seniors.

Simple, Flexible, Trigonometric Taper Equations

Treesearch

Charles E. Thomas; Bernard R. Parresol

1991-01-01

There have been numerous approaches to modeling stem form in recent decades. The majority have concentrated on the simpler coniferous bole form and have become increasingly complex mathematical expressions. Use of trigonometric equations provides a simple expression of taper that is flexible enough to fit both coniferous and hard-wood bole forms. As an illustration, we...

40 CFR 1065.910 - PEMS auxiliary equipment for field testing.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... (ii) We recommend that you use flexible connectors that do not exceed a length of three times their... 300 series stainless steel tubing to connect between flexible connectors. Tubing may be straight or bent to accommodate vehicle geometry. You may use “T” or “Y” fittings made of 300 series stainless...

40 CFR 1065.910 - PEMS auxiliary equipment for field testing.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... (ii) We recommend that you use flexible connectors that do not exceed a length of three times their... 300 series stainless steel tubing to connect between flexible connectors. Tubing may be straight or bent to accommodate vehicle geometry. You may use “T” or “Y” fittings made of 300 series stainless...

40 CFR 1065.910 - PEMS auxiliary equipment for field testing.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... (ii) We recommend that you use flexible connectors that do not exceed a length of three times their... 300 series stainless steel tubing to connect between flexible connectors. Tubing may be straight or bent to accommodate vehicle geometry. You may use “T” or “Y” fittings made of 300 series stainless...

40 CFR 1065.910 - PEMS auxiliary equipment for field testing.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... (ii) We recommend that you use flexible connectors that do not exceed a length of three times their... 300 series stainless steel tubing to connect between flexible connectors. Tubing may be straight or bent to accommodate vehicle geometry. You may use “T” or “Y” fittings made of 300 series stainless...

Flexible Scheduling to Fit the Firefighters.

ERIC Educational Resources Information Center

Cox, Clarice Robinson

Three flexible scheduling plans were tried in order that firefighters could take regular college courses despite their 24 hours on the 24 off work schedule. Plan one scheduled the firefighters into a regular Monday-Wednesday-Friday class which they attended every other week, making up missed material outside of class. Plan two scheduled special…

Evolution of Fitness in Experimental Populations of Vesicular Stomatitis Virus

PubMed Central

Elena, S. F.; Gonzalez-Candelas, F.; Novella, I. S.; Duarte, E. A.; Clarke, D. K.; Domingo, E.; Holland, J. J.; Moya, A.

1996-01-01

The evolution of fitness in experimental clonal populations of vesicular stomatitis virus (VSV) has been compared under different genetic (fitness of initial clone) and demographic (population dynamics) regimes. In spite of the high genetic heterogeneity among replicates within experiments, there is a clear effect of population dynamics on the evolution of fitness. Those populations that went through strong periodic bottlenecks showed a decreased fitness in competition experiments with wild type. Conversely, mutant populations that were transferred under the dynamics of continuous population expansions increased their fitness when compared with the same wild type. The magnitude of the observed effect depended on the fitness of the original viral clone. Thus, high fitness clones showed a larger reduction in fitness than low fitness clones under dynamics with included periodic bottleneck. In contrast, the gain in fitness was larger the lower the initial fitness of the viral clone. The quantitative genetic analysis of the trait ``fitness'' in the resulting populations shows that genetic variation for the trait is positively correlated with the magnitude of the change in the same trait. The results are interpreted in terms of the operation of MULLER's ratchet and genetic drift as opposed to the appearance of beneficial mutations. PMID:8849878

The relation of saturated fats and dietary cholesterol to childhood cognitive flexibility.

PubMed

Khan, Naiman A; Raine, Lauren B; Drollette, Eric S; Scudder, Mark R; Hillman, Charles H

2015-10-01

Identification of health behaviors and markers of physiological health associated with childhood cognitive function has important implications for public health policy targeted toward cognitive health throughout the life span. Although previous studies have shown that aerobic fitness and obesity exert contrasting effects on cognitive flexibility among prepubertal children, the extent to which diet plays a role in cognitive flexibility has received little attention. Accordingly, this study examined associations between saturated fats and cholesterol intake and cognitive flexibility, assessed using a task switching paradigm, among prepubertal children between 7 and 10 years (N = 150). Following adjustment of confounding variables (age, sex, socioeconomic status, IQ, VO2max, and BMI), children consuming diets higher in saturated fats exhibited longer reaction time during the task condition requiring greater amounts of cognitive flexibility. Further, increasing saturated fat intake and dietary cholesterol were correlated with greater switch costs, reflecting impaired ability to maintain multiple task sets in working memory and poorer efficiency of cognitive control processes involved in task switching. These data are among the first to indicate that children consuming diets higher in saturated fats and cholesterol exhibit compromised ability to flexibly modulate their cognitive operations, particularly when faced with greater cognitive challenge. Future longitudinal and intervention studies are necessary to comprehensively characterize the interrelationships between diet, aerobic fitness, obesity, and children's cognitive abilities. Copyright © 2015 Elsevier Ltd. All rights reserved.

Deployment dynamics and control of large-scale flexible solar array system with deployable mast

NASA Astrophysics Data System (ADS)

Li, Hai-Quan; Liu, Xiao-Feng; Guo, Shao-Jing; Cai, Guo-Ping

2016-10-01

In this paper, deployment dynamics and control of large-scale flexible solar array system with deployable mast are investigated. The adopted solar array system is introduced firstly, including system configuration, deployable mast and solar arrays with several mechanisms. Then dynamic equation of the solar array system is established by the Jourdain velocity variation principle and a method for dynamics with topology changes is introduced. In addition, a PD controller with disturbance estimation is designed to eliminate the drift of spacecraft mainbody. Finally the validity of the dynamic model is verified through a comparison with ADAMS software and the deployment process and dynamic behavior of the system are studied in detail. Simulation results indicate that the proposed model is effective to describe the deployment dynamics of the large-scale flexible solar arrays and the proposed controller is practical to eliminate the drift of spacecraft mainbody.

Recursive flexible multibody system dynamics using spatial operators

NASA Technical Reports Server (NTRS)

Jain, A.; Rodriguez, G.

1992-01-01

This paper uses spatial operators to develop new spatially recursive dynamics algorithms for flexible multibody systems. The operator description of the dynamics is identical to that for rigid multibody systems. Assumed-mode models are used for the deformation of each individual body. The algorithms are based on two spatial operator factorizations of the system mass matrix. The first (Newton-Euler) factorization of the mass matrix leads to recursive algorithms for the inverse dynamics, mass matrix evaluation, and composite-body forward dynamics for the systems. The second (innovations) factorization of the mass matrix, leads to an operator expression for the mass matrix inverse and to a recursive articulated-body forward dynamics algorithm. The primary focus is on serial chains, but extensions to general topologies are also described. A comparison of computational costs shows that the articulated-body, forward dynamics algorithm is much more efficient than the composite-body algorithm for most flexible multibody systems.

Water-Based Exercise Improves Health-Related Aspects of Fitness in Older Women.

ERIC Educational Resources Information Center

Takeshima, Nobuo; Rogers, Michael E.; Watanabe, Eiji; Brechue, William F.; Okada, Akiyoshi; Yamada, Tadaki; Islam, Mohammod M.; Hayano, Jyunichirou

2002-01-01

Examined the physiological responses of elderly Japanese women to a well-rounded exercise program performed in water. Results indicated that the 12-week program elicited significant improvements in intervention group women's cardiorespiratory fitness, muscular strength, agility, flexibility, body fat, and total cholesterol. Water-based exercise…

Effect of Low-Impact Aerobic Dance on the Functional Fitness of Elderly Women.

ERIC Educational Resources Information Center

Hopkins, David R.; And Others

1990-01-01

Examined effect of low-impact aerobic dance on 53 sedentary older women. After 12 weeks of dance, subjects improved significantly on all functional fitness components except motor control/coordination, including cardiorespiratory endurance, strength/endurance, body agility, flexibility, body fat, and balance. (Author/NB)

46 CFR 28.335 - Fuel systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... (2) Nonmetallic flexible hose is acceptable but must— (i) Not be used in lengths of more than 30... reinforced with wire braid. (iv) Be fitted with suitable, corrosion resistant, compression fittings; and (v) Be installed with two clamps at each end of the hose, if designed for use with clamps. Clamps must...

46 CFR 28.335 - Fuel systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... (2) Nonmetallic flexible hose is acceptable but must— (i) Not be used in lengths of more than 30... reinforced with wire braid. (iv) Be fitted with suitable, corrosion resistant, compression fittings; and (v) Be installed with two clamps at each end of the hose, if designed for use with clamps. Clamps must...

46 CFR 28.335 - Fuel systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... (2) Nonmetallic flexible hose is acceptable but must— (i) Not be used in lengths of more than 30... reinforced with wire braid. (iv) Be fitted with suitable, corrosion resistant, compression fittings; and (v) Be installed with two clamps at each end of the hose, if designed for use with clamps. Clamps must...

46 CFR 28.335 - Fuel systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... (2) Nonmetallic flexible hose is acceptable but must— (i) Not be used in lengths of more than 30... reinforced with wire braid. (iv) Be fitted with suitable, corrosion resistant, compression fittings; and (v) Be installed with two clamps at each end of the hose, if designed for use with clamps. Clamps must...

Manitoba Schools Fitness 1989.

ERIC Educational Resources Information Center

Manitoba Dept. of Education, Winnipeg.

This manual outlines physical fitness tests that may be used in the schools. The tests are based on criterion standards which indicate the levels of achievement at which health risk factors may be reduced. Test theory, protocols, and criterion charts are presented for: (1) muscle strength and endurance, (2) body composition, (3) flexibility, and…

Lessons learned in induced fit docking and metadynamics in the Drug Design Data Resource Grand Challenge 2

NASA Astrophysics Data System (ADS)

Baumgartner, Matthew P.; Evans, David A.

2018-01-01

Two of the major ongoing challenges in computational drug discovery are predicting the binding pose and affinity of a compound to a protein. The Drug Design Data Resource Grand Challenge 2 was developed to address these problems and to drive development of new methods. The challenge provided the 2D structures of compounds for which the organizers help blinded data in the form of 35 X-ray crystal structures and 102 binding affinity measurements and challenged participants to predict the binding pose and affinity of the compounds. We tested a number of pose prediction methods as part of the challenge; we found that docking methods that incorporate protein flexibility (Induced Fit Docking) outperformed methods that treated the protein as rigid. We also found that using binding pose metadynamics, a molecular dynamics based method, to score docked poses provided the best predictions of our methods with an average RMSD of 2.01 Å. We tested both structure-based (e.g. docking) and ligand-based methods (e.g. QSAR) in the affinity prediction portion of the competition. We found that our structure-based methods based on docking with Smina (Spearman ρ = 0.614), performed slightly better than our ligand-based methods (ρ = 0.543), and had equivalent performance with the other top methods in the competition. Despite the overall good performance of our methods in comparison to other participants in the challenge, there exists significant room for improvement especially in cases such as these where protein flexibility plays such a large role.

Effects of Inertial and Geometric Nonlinearities in the Simulation of Flexible Aircraft Dynamics

NASA Astrophysics Data System (ADS)

Bun Tse, Bosco Chun

This thesis examines the relative importance of the inertial and geometric nonlinearities in modelling the dynamics of a flexible aircraft. Inertial nonlinearities are derived by employing an exact definition of the velocity distribution and lead to coupling between the rigid body and elastic motions. The geometric nonlinearities are obtained by applying nonlinear theory of elasticity to the deformations. Peters' finite state unsteady aerodynamic model is used to evaluate the aerodynamic forces. Three approximate models obtained by excluding certain combinations of nonlinear terms are compared with that of the complete dynamics equations to obtain an indication of which terms are required for an accurate representation of the flexible aircraft behavior. A generic business jet model is used for the analysis. The results indicate that the nonlinear terms have a significant effect for more flexible aircraft, especially the geometric nonlinearities which leads to increased damping in the dynamics.

The relationship between active travel to school and health-related fitness in children and adolescents: a systematic review.

PubMed

Lubans, David R; Boreham, Colin A; Kelly, Paul; Foster, Charlie E

2011-01-26

Active travel to school (ATS) has been identified as an important source of physical activity for youth. However, the relationship between ATS and health-related fitness (HRF) among youth remains unclear. A systematic search of seven electronic databases (EMBASE, OVID MEDLINE, PsycINFO, PubMed, Scopus, SPORTDiscus and TRIS on line) was conducted in December 2009 and studies published since 1980 were considered for inclusion. Twenty seven articles were identified that explored the relationship between ATS and the following aspects of HRF: weight status/body composition, cardiorespiratory fitness, muscular fitness and flexibility. Forty-eight percent of the studies that examined the relationship between ATS and weight status/body composition reported significant associations, this increased to 55% once poor quality studies were removed. Furthermore, the findings from five studies, including one longitudinal study, indicate that ATS is positively associated with cardiorespiratory fitness in youth. However, the evidence for the relationships between ATS and muscular fitness or flexibility is equivocal and limited by low study numbers. There is some evidence to suggest that ATS is associated with a healthier body composition and level of cardiorespiratory fitness among youth. Strategies to increase ATS are warranted and should be included in whole-of-school approaches to the promotion of physical activity. © 2011 Lubans et al; licensee BioMed Central Ltd.

A Unified Conformational Selection and Induced Fit Approach to Protein-Peptide Docking

PubMed Central

Trellet, Mikael; Melquiond, Adrien S. J.; Bonvin, Alexandre M. J. J.

2013-01-01

Protein-peptide interactions are vital for the cell. They mediate, inhibit or serve as structural components in nearly 40% of all macromolecular interactions, and are often associated with diseases, making them interesting leads for protein drug design. In recent years, large-scale technologies have enabled exhaustive studies on the peptide recognition preferences for a number of peptide-binding domain families. Yet, the paucity of data regarding their molecular binding mechanisms together with their inherent flexibility makes the structural prediction of protein-peptide interactions very challenging. This leaves flexible docking as one of the few amenable computational techniques to model these complexes. We present here an ensemble, flexible protein-peptide docking protocol that combines conformational selection and induced fit mechanisms. Starting from an ensemble of three peptide conformations (extended, a-helix, polyproline-II), flexible docking with HADDOCK generates 79.4% of high quality models for bound/unbound and 69.4% for unbound/unbound docking when tested against the largest protein-peptide complexes benchmark dataset available to date. Conformational selection at the rigid-body docking stage successfully recovers the most relevant conformation for a given protein-peptide complex and the subsequent flexible refinement further improves the interface by up to 4.5 Å interface RMSD. Cluster-based scoring of the models results in a selection of near-native solutions in the top three for ∼75% of the successfully predicted cases. This unified conformational selection and induced fit approach to protein-peptide docking should open the route to the modeling of challenging systems such as disorder-order transitions taking place upon binding, significantly expanding the applicability limit of biomolecular interaction modeling by docking. PMID:23516555

A unified conformational selection and induced fit approach to protein-peptide docking.

PubMed

Trellet, Mikael; Melquiond, Adrien S J; Bonvin, Alexandre M J J

2013-01-01

Protein-peptide interactions are vital for the cell. They mediate, inhibit or serve as structural components in nearly 40% of all macromolecular interactions, and are often associated with diseases, making them interesting leads for protein drug design. In recent years, large-scale technologies have enabled exhaustive studies on the peptide recognition preferences for a number of peptide-binding domain families. Yet, the paucity of data regarding their molecular binding mechanisms together with their inherent flexibility makes the structural prediction of protein-peptide interactions very challenging. This leaves flexible docking as one of the few amenable computational techniques to model these complexes. We present here an ensemble, flexible protein-peptide docking protocol that combines conformational selection and induced fit mechanisms. Starting from an ensemble of three peptide conformations (extended, a-helix, polyproline-II), flexible docking with HADDOCK generates 79.4% of high quality models for bound/unbound and 69.4% for unbound/unbound docking when tested against the largest protein-peptide complexes benchmark dataset available to date. Conformational selection at the rigid-body docking stage successfully recovers the most relevant conformation for a given protein-peptide complex and the subsequent flexible refinement further improves the interface by up to 4.5 Å interface RMSD. Cluster-based scoring of the models results in a selection of near-native solutions in the top three for ∼75% of the successfully predicted cases. This unified conformational selection and induced fit approach to protein-peptide docking should open the route to the modeling of challenging systems such as disorder-order transitions taking place upon binding, significantly expanding the applicability limit of biomolecular interaction modeling by docking.

Nordic Walking Can Be Incorporated in the Exercise Prescription to Increase Aerobic Capacity, Strength, and Quality of Life for Elderly: A Systematic Review and Meta-Analysis.

PubMed

Bullo, Valentina; Gobbo, Stefano; Vendramin, Barbara; Duregon, Federica; Cugusi, Lucia; Di Blasio, Andrea; Bocalini, Danilo Sales; Zaccaria, Marco; Bergamin, Marco; Ermolao, Andrea

2018-04-01

The aim of this systematic review and meta-analysis was to summarize and analyze the effects of Nordic Walking on physical fitness, body composition, and quality of life in the elderly. Keyword "Nordic Walking" associated with "elderly" AND/OR "aging" AND/OR "old subjects" AND/OR "aged" AND/OR "older adults" were used in the online database MEDLINE, Embase, PubMed, Scopus, PsycINFO, and SPORTDiscus. Only studies written in English language and published in peer-reviewed journals were considered. A meta-analysis was performed and effect sizes calculated. Fifteen studies were identified; age of participants ranged from 60 to 92 years old. Comparing with a sedentary group, effect sizes showed that Nordic Walking was able to improve dynamic balance (0.30), functional balance (0.62), muscle strength of upper (0.66) and lower limbs (0.43), aerobic capacity (0.92), cardiovascular outcomes (0.23), body composition (0.30), and lipid profile (0.67). It seemed that Nordic Walking had a negative effect on static balance (-0.72). Comparing with a walking (alone) training, effect sizes showed that Nordic Walking improved the dynamic balance (0.30), flexibility of the lower body (0.47), and quality of life (0.53). Walking training was more effective in improving aerobic capacity (-0.21). Comparing Nordic Walking with resistance training, effect sizes showed that Nordic Walking improved dynamic balance (0.33), muscle strength of the lower body (0.39), aerobic capacity (0.75), flexibility of the upper body (0.41), and the quality of life (0.93). Nordic Walking can be considered as a safe and accessible form of aerobic exercise for the elderly population, able to improve cardiovascular outcomes, muscle strength, balance ability, and quality of life.

Acute Effects of Foam Rolling, Static Stretching, and Dynamic Stretching During Warm-ups on Muscular Flexibility and Strength in Young Adults.

PubMed

Su, Hsuan; Chang, Nai-Jen; Wu, Wen-Lan; Guo, Lan-Yuen; Chu, I-Hua

2017-11-01

Foam rolling has been proposed to improve muscle function, performance, and joint range of motion (ROM). However, whether a foam rolling protocol can be adopted as a warm-up to improve flexibility and muscle strength is unclear. To examine and compare the acute effects of foam rolling, static stretching, and dynamic stretching used as part of a warm-up on flexibility and muscle strength of knee flexion and extension. Crossover study. University research laboratory. 15 male and 15 female college students (age 21.43 ± 1.48 y, weight 65.13 ± 12.29 kg, height 166.90 ± 6.99 cm). Isokinetic peak torque was measured during knee extension and flexion at an angular velocity of 60°/second. Flexibility of the quadriceps was assessed by the modified Thomas test, while flexibility of the hamstrings was assessed using the sit-and-reach test. The 3 interventions were performed by all participants in random order on 3 days separated by 48-72 hours. The flexibility test scores improved significantly more after foam rolling as compared with static and dynamic stretching. With regard to muscle strength, only knee extension peak torque (pre vs. postintervention) improved significantly after the dynamic stretching and foam rolling, but not after static stretching. Knee flexion peak torque remained unchanged. Foam rolling is more effective than static and dynamic stretching in acutely increasing flexibility of the quadriceps and hamstrings without hampering muscle strength, and may be recommended as part of a warm-up in healthy young adults.

Organizational flexibility as a strategic option: fostering dynamic capabilities of hospitals.

PubMed

Dias, Casimiro; Escoval, Ana

2014-01-01

The main purpose of this article is to examine how the internal and external dimensions of organizational flexibility impact hospital performance. Results reveal that matching internal and external flexibilities contributes to the development of capabilities to adopt new strategic options. Such interactions have a significant impact in terms of hospital performance. A cluster of dynamic hospitals, which is characterised by high levels of both internal and external flexibilities, (instead of that have high levels of both internal and external flexibilities) was found to have the double level of performance compared with other clusters. The implications for research and managerial practice are discussed. Copyright © 2014 Longwoods Publishing.

INFOS: spectrum fitting software for NMR analysis.

PubMed

Smith, Albert A

2017-02-01

Software for fitting of NMR spectra in MATLAB is presented. Spectra are fitted in the frequency domain, using Fourier transformed lineshapes, which are derived using the experimental acquisition and processing parameters. This yields more accurate fits compared to common fitting methods that use Lorentzian or Gaussian functions. Furthermore, a very time-efficient algorithm for calculating and fitting spectra has been developed. The software also performs initial peak picking, followed by subsequent fitting and refinement of the peak list, by iteratively adding and removing peaks to improve the overall fit. Estimation of error on fitting parameters is performed using a Monte-Carlo approach. Many fitting options allow the software to be flexible enough for a wide array of applications, while still being straightforward to set up with minimal user input.

Control and dynamics of a flexible spacecraft during stationkeeping maneuvers

NASA Technical Reports Server (NTRS)

Liu, D.; Yocum, J.; Kang, D. S.

1991-01-01

A case study of a spacecraft having flexible solar arrays is presented. A stationkeeping attitude control mode using both earth and rate gyro reference signals and a flexible vehicle dynamics modeling and implementation is discussed. The control system is designed to achieve both pointing accuracy and structural mode stability during stationkeeping maneuvers. Reduction of structural mode interactions over the entire mode duration is presented. The control mode using a discrete time observer structure is described to show the convergence of the spacecraft attitude transients during Delta-V thrusting maneuvers without preloading thrusting bias to the onboard control processor. The simulation performance using the three axis, body stabilized nonlinear dynamics is provided. The details of a five body dynamics model are discussed. The spacecraft is modeled as a central rigid body having cantilevered flexible antennas, a pair of flexible articulated solar arrays, and to gimballed momentum wheels. The vehicle is free to undergo unrestricted rotations and translations relative to inertial space. A direct implementation of the equations of motion is compared to an indirect implementation that uses a symbolic manipulation software to generate rigid body equations.

Pancreatic Ribonucleases Superfamily Dynamics

DOE Data Explorer

Agarwal, Pratul

2016-01-01

This data set consists of molecular dynamics simulations based flexibility/dynamics derived for family members of pancreatic ribonucleases. The results are based on two independent 0.5 microsecond trajectories for each of the 23 members. The flexibility is computed at aggregation of first ten quasi-harmonic modes, and indicated in the temperature factor column of PDB (protein data bank) file format.

Perception of Physical Fitness and Exercise Self-Efficacy and Its Contribution to the Relationship between Body Dissatisfaction and Physical Fitness in Female Minority Children.

PubMed

Flanagan, Emily W; Perry, Arlette C

2018-06-06

Body Dissatisfaction (BD) and low physical self-concept and exercise efficacy have been linked to poor physical fitness levels and adverse health outcomes in children. The purpose of this study was to examine the relationship between BD, physical fitness, exercise self-efficacy, and self-Perception of Physical Fitness (PFP) in Latina and Black female children. Twenty-eight Latina and Black children enrolled in an elementary afterschool program, aged 8⁻12, completed surveys evaluating body dissatisfaction, exercise efficacy, PFP, and measures of physical fitness. Subjects exhibited moderate but significant inverse relationships between BD and PFP in strength ( r = −0.459), agility ( r = −0.382), aerobic fitness ( r = −0.354), and flexibility ( r = −0.461) ( p < 0.05 for all). There was a significant negative correlation between exercise efficacy and BD ( r = −4.2; p < 0.05). Power ( r = 0.51) and flexibility ( r = 0.42) were the only physical fitness measures significantly and positively related to children’s PFP ( p < 0.05). A significant medium inverse relationship was also found between BD and aerobic fitness scores ( r = −0.381; p < 0.05). However, after controlling for exercise efficacy or perception of physical fitness, the relationship between BD and aerobic fitness was not significant ( p > 0.05). Findings suggest that positive PFP and positive performance in several physical fitness measures are associated with lower levels of BD in minority female children. Furthermore, evidence suggests exercise efficacy and PFP can mediate the relationship body image and aerobic fitness. These findings suggest that PFP, more so than measured physical fitness, was associated with lower levels of BD in minority female children. These results have important implications for programs designed to improve physical fitness and mental health in minority children.

Leisure-time physical activity and physical fitness of male adolescents in Oman.

PubMed

Khoo, Selina; Al-Shamli, Ali Khalifa

2012-01-01

This study investigated the relationship between leisure-time physical activity and physical fitness (cardiovascular fitness, body fat percentage, flexibility, muscle strength, and endurance) of 10th-grade male students in Oman. Data were collected from 330 students. All participants completed a descriptive questionnaire, a 1 mile walk/run test; a skinfold analysis of the chest, abdomen, and thigh; a sit and reach test; a hand grip test; and a 1-minute sit-up test. Students spent an average of 19.20 ± 6.77 hours on sedentary activities, 3.46 ± 2.11 hours on sports activities, and 11.22 ± 9.24 hours working per week. The students had an average body fat percentage of 6.38% ± 4.67%, muscle strength 38.04 ± 7.55 kg, flexibility 38.01 ± 7.41 cm, abdominal muscle endurance 38.85 ± 8.15 times/min, and cardiovascular endurance 8.10 ± 1.65 minutes.

Functional fitness improvements after a worksite-based yoga initiative.

PubMed

Cowen, Virginia S

2010-01-01

This study explored the benefits of yoga on functional fitness, flexibility, and perceived stress. A quasi-experimental design was used to measure benefits of yoga in sample of firefighters from a major metropolitan fire department. Yoga classes were conducted on-shift, in the fire stations over the period of 6 weeks. The classes included pranayama (breathing), asana (postures), and savasana (relaxation); 108 firefighters enrolled in the study, most were physically active but had no prior experience with yoga. Baseline and post-yoga assessments were completed by 77 participants. Paired t-tests revealed significant improvements in the Functional Movement Screen, a seven item test that measures functional fitness. Improvements were also noted in trunk flexibility and perceived stress. Participants also reported favorable perceptions of yoga: feeling more focused and less musculoskeletal pain. These findings - along with the retention of the majority of the participants - indicate that participants benefited from yoga.

A Wearable Microfluidic Sensing Patch for Dynamic Sweat Secretion Analysis.

PubMed

Nyein, Hnin Yin Yin; Tai, Li-Chia; Ngo, Quynh Phuong; Chao, Minghan; Zhang, George B; Gao, Wei; Bariya, Mallika; Bullock, James; Kim, Hyungjin; Fahad, Hossain M; Javey, Ali

2018-05-25

Wearable sweat sensing is a rapidly rising research area driven by its promising potential in health, fitness, and diagnostic applications. Despite the growth in the field, major challenges in relation to sweat metrics remain to be addressed. These challenges include sweat rate monitoring for its complex relation with sweat compositions and sweat sampling for sweat dynamics studies. In this work, we present a flexible microfluidic sweat sensing patch that enhances real-time electrochemical sensing and sweat rate analysis via sweat sampling. The device contains a spiral-patterned microfluidic component that is embedded with ion-selective sensors and an electrical impedance-based sweat rate sensor on a flexible plastic substrate. The patch is enabled to autonomously perform sweat analysis by interfacing the sensing component with a printed circuit board that is capable of on-site signal conditioning, analysis, and transmission. Progressive sweat flow in the microfluidic device, governed by the pressure induced by the secreted sweat, enhances sweat sampling and electrochemical detection via a defined sweat collection chamber and a directed sweat route. The characteristic of the sweat rate sensor is validated through a theoretical simulation, and the precision and accuracy of the flow rate is verified with a commercial syringe pump and a Macroduct sweat collector. On-body simultaneous monitoring of ion (H + , Na + , K + , Cl - ) concentration and sweat rate is also demonstrated for sensor functionality. This sweat sensing patch provides an integrated platform for a comprehensive sweat secretion analysis and facilitates physiological and clinical investigations by closely monitoring interrelated sweat parameters.

Effect of Custom-Molded Foot Orthoses on Foot Pain and Balance in Children With Symptomatic Flexible Flat Feet

PubMed Central

Lee, Hong-Jae; Lim, Kil-Byung; Yoo, JeeHyun; Yun, Hyun-Ju; Jeong, Tae-Ho

2015-01-01

Objective To evaluate the effect of custom-molded foot orthoses on foot pain and balance in children with symptomatic flexible flat foot 1 month and 3 months after fitting foot orthosis. Method A total of 24 children over 6 years old with flexible flat feet and foot pain for at least 6 months were recruited for this study. Their resting calcaneal stance position and calcaneal pitch angle were measured. Individual custom-molded rigid foot orthoses were prescribed using inverted orthotic technique to control foot overpronation. Pain questionnaire was used to obtain pain sites, degree, and frequency. Balancing ability was determined using computerized posturography. These evaluations were performed prior to custom-molded foot orthoses, 1 month, and 3 months after fitting foot orthoses. Result Of 24 children with symptomatic flexible flat feet recruited for this study, 20 completed the study. Significant (p<0.001) improvements in pain degree and frequency were noted after 1 and 3 months of custom-molded foot orthoses. In addition, significant (p<0.05) improvement in balancing ability was found after 3 months of custom-molded foot orthoses. Conclusion Short-term use of custom-molded foot orthoses significantly improved foot pain and balancing ability in children with symptomatic flexible flat foot. PMID:26798604

Docking ligands into flexible and solvated macromolecules. 7. Impact of protein flexibility and water molecules on docking-based virtual screening accuracy.

PubMed

Therrien, Eric; Weill, Nathanael; Tomberg, Anna; Corbeil, Christopher R; Lee, Devin; Moitessier, Nicolas

2014-11-24

The use of predictive computational methods in the drug discovery process is in a state of continual growth. Over the last two decades, an increasingly large number of docking tools have been developed to identify hits or optimize lead molecules through in-silico screening of chemical libraries to proteins. In recent years, the focus has been on implementing protein flexibility and water molecules. Our efforts led to the development of Fitted first reported in 2007 and further developed since then. In this study, we wished to evaluate the impact of protein flexibility and occurrence of water molecules on the accuracy of the Fitted docking program to discriminate active compounds from inactive compounds in virtual screening (VS) campaigns. For this purpose, a total of 171 proteins cocrystallized with small molecules representing 40 unique enzymes and receptors as well as sets of known ligands and decoys were selected from the Protein Data Bank (PDB) and the Directory of Useful Decoys (DUD), respectively. This study revealed that implementing displaceable crystallographic or computationally placed particle water molecules and protein flexibility can improve the enrichment in active compounds. In addition, an informed decision based on library diversity or research objectives (hit discovery vs lead optimization) on which implementation to use may lead to significant improvements.

Relationship of functional fitness with daily steps in community-dwelling older adults.

PubMed

de Melo, Lucelia Luna; Menec, Verena H; Ready, A Elizabeth

2014-01-01

Walking is the main type of physical activity among community-dwelling older adults and it is associated with various health benefits. However, there is limited evidence about the relationship between functional fitness and walking performed under independent living conditions among older adults. This study examined the relationship between functional fitness and steps walked per day among older adults, both assessed objectively, with performance-based measures accounting for the effect of age, gender, and chronic conditions. In this cross-sectional study, 60 participants aged 65 years or older (mean = 76.9 ± 7.3 years, range 65-92 years) wore pedometers for 3 consecutive days. Functional fitness was measured using the Functional Fitness Test (lower and upper body strength, endurance, lower and upper body flexibility, agility/balance). The outcome measure was the mean number of steps walked for 3 days with participants classified into tertiles: low walkers (<3000 steps), medium walkers (≥3000 < 6500 steps), and high walkers (≥6500 steps). After controlling for age, gender, and the number of chronic conditions, none of the functional fitness parameters was significantly associated with steps taken per day when comparing medium walkers with low walkers. In contrast, all functional fitness parameters, except upper body flexibility, were significantly associated with steps taken per day when comparing high walkers with low walkers. In this sample of older adults, greater functional fitness was associated only with relatively high levels of walking involving 6500 steps per day or more. It was not related to medium walking levels. The findings point to the importance of interventions to maintain or enhance functional fitness among older adults.

Deleterious effects of obesity on physical fitness in pre-pubertal children.

PubMed

Ceschia, Arianna; Giacomini, Stefano; Santarossa, Simone; Rugo, Miriam; Salvadego, Desy; Da Ponte, Alessandro; Driussi, Caterina; Mihaleje, Martina; Poser, Stefano; Lazzer, Stefano

2016-01-01

The prevalence of obesity in children has increased dramatically during the past decades in Europe and understanding physical fitness and its components in children is critical to design and implement effective interventions. The objective of the present study was to analyse the association between physical fitness (aerobic, speed, agility, power, flexibility and balance) and body mass index (BMI) in pre-pubertal children. A total of 2411 healthy schoolchildren (7-11 years) participated in this study. Anthropometric characteristics and body composition were assessed by skinfold thickness. Physical fitness was measured by nine physical fitness tests: endurance running, 20 m running speed, agility, handgrip strength, standing long jump and squat jump, sit and reach, medicine ball forward throw and static balance. No relevant differences were observed between boys and girls regarding anthropometric characteristics, body composition and physical fitness. However, overweight and obese children showed significantly lower physical fitness levels in endurance running, speed and agility (mean: +18.8, +5.5 and +14.5% of time to complete tasks, respectively), lower limb power normalised to body mass (-23.3%) and balance tests (number of falls: +165.5%) than their normal weight counterparts. On the other hand, obesity did not affect handgrip, throwing and flexibility. In conclusion, increased BMI was associated with lower performance capabilities limiting proper motor skill development, which directly affects the ability of children to take on sports skills. Actions undertaken to promote children's wellness and fitness should be prioritised and introduced early in life with the aim of enhancing physical fitness as well as preventing overweight and obesity.

Molecular dynamics simulations of a K+ channel blocker: Tc1 toxin from Tityus cambridgei.

PubMed

Grottesi, Alessandro; Sansom, Mark S P

2003-01-30

Toxins that block voltage-gated potassium (Kv) channels provide a possible template for improved homology models of the Kv pore. In assessing the interactions of Kv channels and their toxins it is important to determine the dynamic flexibility of the toxins. Multiple 10 ns duration molecular dynamics simulations combined with essential dynamics analysis have been used to explore the flexibility of four different Kv channel-blocking toxins. Three toxins (Tc1, AgTx and ChTx) share a common fold. They also share a common pattern of conformational dynamics, as revealed by essential dynamics analysis of the simulation results. This suggests that some aspects of dynamic behaviour are conserved across a single protein fold class. In each of these three toxins, the residue exhibiting minimum flexibility corresponds to a conserved lysine residue that is suggested to interact with the filter domain of the channel. Thus, comparative simulations reveal functionally important conservation of molecular dynamics as well as protein fold across a family of related toxins.

Mixture Hidden Markov Models in Finance Research

NASA Astrophysics Data System (ADS)

Dias, José G.; Vermunt, Jeroen K.; Ramos, Sofia

Finite mixture models have proven to be a powerful framework whenever unobserved heterogeneity cannot be ignored. We introduce in finance research the Mixture Hidden Markov Model (MHMM) that takes into account time and space heterogeneity simultaneously. This approach is flexible in the sense that it can deal with the specific features of financial time series data, such as asymmetry, kurtosis, and unobserved heterogeneity. This methodology is applied to model simultaneously 12 time series of Asian stock markets indexes. Because we selected a heterogeneous sample of countries including both developed and emerging countries, we expect that heterogeneity in market returns due to country idiosyncrasies will show up in the results. The best fitting model was the one with two clusters at country level with different dynamics between the two regimes.

Crash Testing of Helicopter Airframe Fittings

NASA Technical Reports Server (NTRS)

Clarke, Charles W.; Townsend, William; Boitnott, Richard

2004-01-01

As part of the Rotary Wing Structures Technology Demonstration (RWSTD) program, a surrogate RAH-66 seat attachment fitting was dynamically tested to assess its response to transient, crash impact loads. The dynamic response of this composite material fitting was compared to the performance of an identical fitting subjected to quasi-static loads of similar magnitude. Static and dynamic tests were conducted of both smaller bench level and larger full-scale test articles. At the bench level, the seat fitting was supported in a steel fixture, and in the full-scale tests, the fitting was integrated into a surrogate RAH-66 forward fuselage. Based upon the lessons learned, an improved method to design, analyze, and test similar composite material fittings is proposed.

Computation of structural flexibility for bridge health monitoring using ambient modal data

DOT National Transportation Integrated Search

1996-01-01

The issues surrounding the use of ambient vibration modes for the location of structural damage via dynamically : measured flexibility are examined. Several methods for obtaining the required mass-normalized : dynamic mode shapes from ambient modal d...

Exhibit D modular design attitude control system study

NASA Technical Reports Server (NTRS)

Chichester, F.

1984-01-01

A dynamically equivalent four body approximation of the NASTRAN finite element model supplied for hybrid deployable truss to support the digital computer simulation of the ten body model of the flexible space platform that incorporates the four body truss model were investigated. Coefficients for sensitivity of state variables of the linearized model of the three axes rotational dynamics of the prototype flexible spacecraft were generated with respect to the model's parameters. Software changes required to accommodate addition of another rigid body to the five body model of the rotational dynamics of the prototype flexible spacecraft were evaluated.

Application of finite-element methods to dynamic analysis of flexible spatial and co-planar linkage systems, part 2

NASA Technical Reports Server (NTRS)

Dubowsky, Steven

1989-01-01

An approach is described to modeling the flexibility effects in spatial mechanisms and manipulator systems. The method is based on finite element representations of the individual links in the system. However, it should be noted that conventional finite element methods and software packages will not handle the highly nonlinear dynamic behavior of these systems which results form their changing geometry. In order to design high-performance lightweight systems and their control systems, good models of their dynamic behavior which include the effects of flexibility are required.

Aggregation of flexible polyelectrolytes: Phase diagram and dynamics.

PubMed

Tom, Anvy Moly; Rajesh, R; Vemparala, Satyavani

2017-10-14

Similarly charged polymers in solution, known as polyelectrolytes, are known to form aggregated structures in the presence of oppositely charged counterions. Understanding the dependence of the equilibrium phases and the dynamics of the process of aggregation on parameters such as backbone flexibility and charge density of such polymers is crucial for insights into various biological processes which involve biological polyelectrolytes such as protein, DNA, etc. Here, we use large-scale coarse-grained molecular dynamics simulations to obtain the phase diagram of the aggregated structures of flexible charged polymers and characterize the morphology of the aggregates as well as the aggregation dynamics, in the presence of trivalent counterions. Three different phases are observed depending on the charge density: no aggregation, a finite bundle phase where multiple small aggregates coexist with a large aggregate and a fully phase separated phase. We show that the flexibility of the polymer backbone causes strong entanglement between charged polymers leading to additional time scales in the aggregation process. Such slowing down of the aggregation dynamics results in the exponent, characterizing the power law decay of the number of aggregates with time, to be dependent on the charge density of the polymers. These results are contrary to those obtained for rigid polyelectrolytes, emphasizing the role of backbone flexibility.

Force-field parametrization and molecular dynamics simulations of Congo red

NASA Astrophysics Data System (ADS)

Król, Marcin; Borowski, Tomasz; Roterman, Irena; Piekarska, Barbara; Stopa, Barbara; Rybarska, Joanna; Konieczny, Leszek

2004-01-01

Congo red, a diazo dye widely used in medical diagnosis, is known to form supramolecular systems in solution. Such a supramolecular system may interact with various proteins. In order to examine the nature of such complexes empirical force field parameters for the Congo red molecule were developed. The parametrization of bonding terms closely followed the methodology used in the development of the charmm22 force field, except for the calculation of charges. Point charges were calculated from a fit to a quantum mechanically derived electrostatic potential using the CHELP-BOW method. Obtained parameters were tested in a series of molecular dynamics simulations of both a single molecule and a micelle composed of Congo red molecules. It is shown that newly developed parameters define a stable minimum on the hypersurface of the potential energy and crystal and ab initio geometries and rotational barriers are well reproduced. Furthermore, rotations around C-N bonds are similar to torsional vibrations observed in crystals of diphenyl-diazene, which confirms that the flexibility of the molecule is correct. Comparison of results obtained from micelles molecular dynamics simulations with experimental data shows that the thermal dependence of micelle creation is well reproduced.

Flexible Interior-Impression-Molding Tray

NASA Technical Reports Server (NTRS)

Anders, Jeffrey E.

1991-01-01

Device used inside combustion chamber of complicated shape for nondestructive evaluation of qualities of welds, including such features as offset, warping, misalignment of parts, and dropthrough. Includes flexible polypropylene tray trimmed to fit desired interior surface contour. Two neodymium boron magnets and inflatable bladder attached to tray. Tray and putty inserted in cavity to make mold of interior surface.

Skill-related physical fitness versus aerobic fitness as a predictor of executive functioning in children with intellectual disabilities or borderline intellectual functioning.

PubMed

Hartman, Esther; Smith, Joanne; Houwen, Suzanne; Visscher, Chris

2017-05-01

Children with intellectual disabilities (ID) or borderline intellectual disabilities (BIF) often demonstrate impairments in executive functioning (EF). Studies in typically developing children show that aerobic fitness (AF) is positively related with EF. Skill-related physical fitness (SF) might, however, be a stronger predictor of EF than AF, as cognitive challenges are inherent in application of these skills. In this study, AF and SF were examined simultaneously in relationship with domains of EF in children with ID or BIF. Seventy-three children (age range 8-11; 51 boys) with ID (IQ range 56-79) or BIF (IQ range 71-79) were measured annually over a period of 4 years on AF (20-m endurance shuttle run test) and SF (plate tapping and 10×5m run). EF was measured with the Stroop Color-Word test (inhibition), Trailmaking and Fluency test (cognitive flexibility), Self-ordered pointing task (working memory) and the Tower of London (planning). Multilevel models showed that SF was significantly associated with inhibition and both measures of cognitive flexibility, but in the same models no significant associations between AF and EF were found. In addition, age was significantly related to working memory and cognitive flexibility, favouring the older children. In children with ID or BIF, SF is of greater importance than AF in relationship with core domains of EF. Copyright © 2017 Elsevier Ltd. All rights reserved.

Feedback tracking control for dynamic morphing of piezocomposite actuated flexible wings

NASA Astrophysics Data System (ADS)

Wang, Xiaoming; Zhou, Wenya; Wu, Zhigang

2018-03-01

Aerodynamic properties of flexible wings can be improved via shape morphing using piezocomposite materials. Dynamic shape control of flexible wings is investigated in this study by considering the interactions between structural dynamics, unsteady aerodynamics and piezo-actuations. A novel antisymmetric angle-ply bimorph configuration of piezocomposite actuators is presented to realize coupled bending-torsional shape control. The active aeroelastic model is derived using finite element method and Theodorsen unsteady aerodynamic loads. A time-varying linear quadratic Gaussian (LQG) tracking control system is designed to enhance aerodynamic lift with pre-defined trajectories. Proof-of-concept simulations of static and dynamic shape control are presented for a scaled high-aspect-ratio wing model. Vibrations of the wing and fluctuations in aerodynamic forces are caused by using the static voltages directly in dynamic shape control. The lift response has tracked the trajectories well with favorable dynamic morphing performance via feedback tracking control.

CBS Genome Atlas Database: a dynamic storage for bioinformatic results and sequence data.

PubMed

Hallin, Peter F; Ussery, David W

2004-12-12

Currently, new bacterial genomes are being published on a monthly basis. With the growing amount of genome sequence data, there is a demand for a flexible and easy-to-maintain structure for storing sequence data and results from bioinformatic analysis. More than 150 sequenced bacterial genomes are now available, and comparisons of properties for taxonomically similar organisms are not readily available to many biologists. In addition to the most basic information, such as AT content, chromosome length, tRNA count and rRNA count, a large number of more complex calculations are needed to perform detailed comparative genomics. DNA structural calculations like curvature and stacking energy, DNA compositions like base skews, oligo skews and repeats at the local and global level are just a few of the analysis that are presented on the CBS Genome Atlas Web page. Complex analysis, changing methods and frequent addition of new models are factors that require a dynamic database layout. Using basic tools like the GNU Make system, csh, Perl and MySQL, we have created a flexible database environment for storing and maintaining such results for a collection of complete microbial genomes. Currently, these results counts to more than 220 pieces of information. The backbone of this solution consists of a program package written in Perl, which enables administrators to synchronize and update the database content. The MySQL database has been connected to the CBS web-server via PHP4, to present a dynamic web content for users outside the center. This solution is tightly fitted to existing server infrastructure and the solutions proposed here can perhaps serve as a template for other research groups to solve database issues. A web based user interface which is dynamically linked to the Genome Atlas Database can be accessed via www.cbs.dtu.dk/services/GenomeAtlas/. This paper has a supplemental information page which links to the examples presented: www.cbs.dtu.dk/services/GenomeAtlas/suppl/bioinfdatabase.

Dynamic Excitatory and Inhibitory Gain Modulation Can Produce Flexible, Robust and Optimal Decision-making

PubMed Central

Niyogi, Ritwik K.; Wong-Lin, KongFatt

2013-01-01

Behavioural and neurophysiological studies in primates have increasingly shown the involvement of urgency signals during the temporal integration of sensory evidence in perceptual decision-making. Neuronal correlates of such signals have been found in the parietal cortex, and in separate studies, demonstrated attention-induced gain modulation of both excitatory and inhibitory neurons. Although previous computational models of decision-making have incorporated gain modulation, their abstract forms do not permit an understanding of the contribution of inhibitory gain modulation. Thus, the effects of co-modulating both excitatory and inhibitory neuronal gains on decision-making dynamics and behavioural performance remain unclear. In this work, we incorporate time-dependent co-modulation of the gains of both excitatory and inhibitory neurons into our previous biologically based decision circuit model. We base our computational study in the context of two classic motion-discrimination tasks performed in animals. Our model shows that by simultaneously increasing the gains of both excitatory and inhibitory neurons, a variety of the observed dynamic neuronal firing activities can be replicated. In particular, the model can exhibit winner-take-all decision-making behaviour with higher firing rates and within a significantly more robust model parameter range. It also exhibits short-tailed reaction time distributions even when operating near a dynamical bifurcation point. The model further shows that neuronal gain modulation can compensate for weaker recurrent excitation in a decision neural circuit, and support decision formation and storage. Higher neuronal gain is also suggested in the more cognitively demanding reaction time than in the fixed delay version of the task. Using the exact temporal delays from the animal experiments, fast recruitment of gain co-modulation is shown to maximize reward rate, with a timescale that is surprisingly near the experimentally fitted value. Our work provides insights into the simultaneous and rapid modulation of excitatory and inhibitory neuronal gains, which enables flexible, robust, and optimal decision-making. PMID:23825935

Using Sport Education to Implement a CrossFit Unit

ERIC Educational Resources Information Center

Sibley, Benjamin A.

2012-01-01

The sport education (SE) model has been used extensively to teach sports at the middle and high school levels, and the flexibility of the model has been demonstrated in its application to fitness units as well. Infusing new content into this well-established and familiar curricular model can increase student motivation and interest while…

Predicting Performance on a Firefighter's Ability Test from Fitness Parameters

ERIC Educational Resources Information Center

Michaelides, Marcos A.; Parpa, Koulla M.; Thompson, Jerald; Brown, Barry

2008-01-01

The purpose of this project was to identify the relationships between various fitness parameters such as upper body muscular endurance, upper and lower body strength, flexibility, body composition and performance on an ability test (AT) that included simulated firefighting tasks. A second intent was to create a regression model that would predict…

New Approach to School Health Initiatives: Using Fitness Measures Instead of Body Mass Index to Evaluate Outcomes

ERIC Educational Resources Information Center

Phelps, Joshua; Smith, Amanda; Parker, Stephany; Hermann, Janice

2016-01-01

Oklahoma Cooperative Extension Service provided elementary school students with a program that included a noncompetitive physical activity component: circuit training that combined cardiovascular, strength, and flexibility activities without requiring high skill levels. The intent was to improve fitness without focusing on body mass index as an…

Examinations of tRNA Range of Motion Using Simulations of Cryo-EM Microscopy and X-Ray Data

PubMed Central

Caulfield, Thomas R.; Devkota, Batsal; Rollins, Geoffrey C.

2011-01-01

We examined tRNA flexibility using a combination of steered and unbiased molecular dynamics simulations. Using Maxwell's demon algorithm, molecular dynamics was used to steer X-ray structure data toward that from an alternative state obtained from cryogenic-electron microscopy density maps. Thus, we were able to fit X-ray structures of tRNA onto cryogenic-electron microscopy density maps for hybrid states of tRNA. Additionally, we employed both Maxwell's demon molecular dynamics simulations and unbiased simulation methods to identify possible ribosome-tRNA contact areas where the ribosome may discriminate tRNAs during translation. Herein, we collected >500 ns of simulation data to assess the global range of motion for tRNAs. Biased simulations can be used to steer between known conformational stop points, while unbiased simulations allow for a general testing of conformational space previously unexplored. The unbiased molecular dynamics data describes the global conformational changes of tRNA on a sub-microsecond time scale for comparison with steered data. Additionally, the unbiased molecular dynamics data was used to identify putative contacts between tRNA and the ribosome during the accommodation step of translation. We found that the primary contact regions were H71 and H92 of the 50S subunit and ribosomal proteins L14 and L16. PMID:21716650

Research on The Construction of Flexible Multi-body Dynamics Model based on Virtual Components

NASA Astrophysics Data System (ADS)

Dong, Z. H.; Ye, X.; Yang, F.

2018-05-01

Focus on the harsh operation condition of space manipulator, which cannot afford relative large collision momentum, this paper proposes a new concept and technology, called soft-contact technology. In order to solve the problem of collision dynamics of flexible multi-body system caused by this technology, this paper also proposes the concepts of virtual components and virtual hinges, and constructs flexible dynamic model based on virtual components, and also studies on its solutions. On this basis, this paper uses NX to carry out model and comparison simulation for space manipulator in 3 different modes. The results show that using the model of multi-rigid body + flexible body hinge + controllable damping can make effective control on amplitude for the force and torque caused by target satellite collision.

Analysis of flexible aircraft longitudinal dynamics and handling qualities. Volume 1: Analysis methods

NASA Technical Reports Server (NTRS)

Waszak, M. R.; Schmidt, D. S.

1985-01-01

As aircraft become larger and lighter due to design requirements for increased payload and improved fuel efficiency, they will also become more flexible. For highly flexible vehicles, the handling qualities may not be accurately predicted by conventional methods. This study applies two analysis methods to a family of flexible aircraft in order to investigate how and when structural (especially dynamic aeroelastic) effects affect the dynamic characteristics of aircraft. The first type of analysis is an open loop model analysis technique. This method considers the effects of modal residue magnitudes on determining vehicle handling qualities. The second method is a pilot in the loop analysis procedure that considers several closed loop system characteristics. Volume 1 consists of the development and application of the two analysis methods described above.

Thermal shock induced dynamics of a spacecraft with a flexible deploying boom

NASA Astrophysics Data System (ADS)

Shen, Zhenxing; Li, Huijian; Liu, Xiaoning; Hu, Gengkai

2017-12-01

The dynamics in the process of deployment of a flexible extendible boom as a deployable structure on the spacecraft is studied. For determining the thermally induced vibrations of the boom subjected to an incident solar heat flux, an axially moving thermal-dynamic beam element based on the absolute nodal coordinate formulation which is able to precisely describe the large displacement, rotation and deformation of flexible body is presented. For the elastic forces formulation of variable-length beam element, the enhanced continuum mechanics approach is adopted, which can eliminate the Poisson locking effect, and take into account the tension-bending-torsion coupling deformations. The main body of the spacecraft, modeled as a rigid body, is described using the natural coordinates method. In the derived nonlinear thermal-dynamic equations of rigid-flexible multibody system, the mass matrix is time-variant, and a pseudo damping matrix which is without actual energy dissipation, and a heat conduction matrix which is relative to the moving speed and the number of beam element are arisen. Numerical results give the dynamic and thermal responses of the nonrotating and spinning spacecraft, respectively, and show that thermal shock has a significant influence on the dynamics of spacecraft.

Dynamic Beam Solutions for Real-Time Simulation and Control Development of Flexible Rockets

NASA Technical Reports Server (NTRS)

Su, Weihua; King, Cecilia K.; Clark, Scott R.; Griffin, Edwin D.; Suhey, Jeffrey D.; Wolf, Michael G.

2016-01-01

In this study, flexible rockets are structurally represented by linear beams. Both direct and indirect solutions of beam dynamic equations are sought to facilitate real-time simulation and control development for flexible rockets. The direct solution is completed by numerically integrate the beam structural dynamic equation using an explicit Newmark-based scheme, which allows for stable and fast transient solutions to the dynamics of flexile rockets. Furthermore, in the real-time operation, the bending strain of the beam is measured by fiber optical sensors (FOS) at intermittent locations along the span, while both angular velocity and translational acceleration are measured at a single point by the inertial measurement unit (IMU). Another study in this paper is to find the analytical and numerical solutions of the beam dynamics based on the limited measurement data to facilitate the real-time control development. Numerical studies demonstrate the accuracy of these real-time solutions to the beam dynamics. Such analytical and numerical solutions, when integrated with data processing and control algorithms and mechanisms, have the potential to increase launch availability by processing flight data into the flexible launch vehicle's control system.

The Direct Effect of Flexible Walls on Fontan Connection Fluid Dynamics

NASA Astrophysics Data System (ADS)

Tree, Mike; Fagan, Kiley; Yoganathan, Ajit

2014-11-01

The current standard treatment for sufferers of congenital heart defects is the palliative Fontan procedure. The Fontan procedure results in an anastomosis of major veins directly to the branched pulmonary arteries bypassing the dysfunctional ventricle. This total cavopulmonary connection (TCPC) extends life past birth, but Fontan patients still suffer long-term complications like decreased exercise capacity, protein-losing enteropathy, and pulmonary arteriovenous malformations (PAVM). These complications have direct ties to fluid dynamics within the connection. Previous experimental and computation studies of Fontan connection fluid dynamics employed rigid vessel models. More recent studies utilize flexible models, but a direct comparison of the fundamental fluid dynamics between rigid and flexible vessels only exists for a computational model, without a direct experimental validation. Thus, this study was a direct comparison of fluid dynamics within a rigid and two compliant idealized TCPCs. 2D particle image velocimetry measurements were collected at the connection center plane. Results include power loss, hepatic flow distribution, fluid shear stress, and flow structure recognition. The effect of flexible walls on these values and clinical impact will be discussed.

Hydrodynamics of a flexible plate between pitching rigid plates

NASA Astrophysics Data System (ADS)

Kim, Junyoung; Kim, Daegyoum

2017-11-01

The dynamics of a flexible plate have been studied as a model problem in swimming and flying of animals and fluid-structure interaction of plants and flags. Motivated by fish schooling and an array of sea grasses, we investigate the dynamics of a flexible plate closely placed between two pitching rigid plates. In most studies on passive deformation of the flexible plate, the plate is immersed in a uniform flow or a wavy flow. However, in this study, the flexible plate experiences periodic deformation by the oscillatory flow generated by the prescribed pitching motion of the rigid plates. In our model, the pitching axes of the rigid plates and the clamping position of the flexible plate are aligned on the same line. The flexible plate shows various responses depending on length and pitching frequency of rigid plates, thickness of a flexible plate, and free-stream velocity. To find the effect of each variable on the response of the flexible plate, amplitude of a trailing edge and modal contribution of a flapping motion are compared, and flow structure around the flexible plate is examined.

Nonlinear model and attitude dynamics of flexible spacecraft with large amplitude slosh

NASA Astrophysics Data System (ADS)

Deng, Mingle; Yue, Baozeng

2017-04-01

This paper is focused on the nonlinearly modelling and attitude dynamics of spacecraft coupled with large amplitude liquid sloshing dynamics and flexible appendage vibration. The large amplitude fuel slosh dynamics is included by using an improved moving pulsating ball model. The moving pulsating ball model is an equivalent mechanical model that is capable of imitating the whole liquid reorientation process. A modification is introduced in the capillary force computation in order to more precisely estimate the settling location of liquid in microgravity or zero-g environment. The flexible appendage is modelled as a three dimensional Bernoulli-Euler beam and the assumed modal method is employed to derive the nonlinear mechanical model for the overall coupled system of liquid filled spacecraft with appendage. The attitude maneuver is implemented by the momentum transfer technique, and a feedback controller is designed. The simulation results show that the liquid sloshing can always result in nutation behavior, but the effect of flexible deformation of appendage depends on the amplitude and direction of attitude maneuver performed by spacecraft. Moreover, it is found that the liquid sloshing and the vibration of flexible appendage are coupled with each other, and the coupling becomes more significant with more rapid motion of spacecraft. This study reveals that the appendage's flexibility has influence on the liquid's location and settling time in microgravity. The presented nonlinear system model can provide an important reference for the overall design of the modern spacecraft composed of rigid platform, liquid filled tank and flexible appendage.

A NASTRAN/TREETOPS solution to a flexible, multi-body dynamics and controls problem on a UNIX workstation

NASA Technical Reports Server (NTRS)

Benavente, Javier E.; Luce, Norris R.

1989-01-01

Demands for nonlinear time history simulations of large, flexible multibody dynamic systems has created a need for efficient interfaces between finite-element modeling programs and time-history simulations. One such interface, TREEFLX, an interface between NASTRAN and TREETOPS, a nonlinear dynamics and controls time history simulation for multibody structures, is presented and demonstrated via example using the proposed Space Station Mobile Remote Manipulator System (MRMS). The ability to run all three programs (NASTRAN, TREEFLX and TREETOPS), in addition to other programs used for controller design and model reduction (such as DMATLAB and TREESEL, both described), under a UNIX Workstation environment demonstrates the flexibility engineers now have in designing, developing and testing control systems for dynamically complex systems.

Multi-carrier modulation analysis and WCP-COQAM proposal

NASA Astrophysics Data System (ADS)

Lin, Hao; Siohan, Pierre

2014-12-01

In the vision towards future radio systems, where access to information and sharing of data is to be available anywhere and anytime to anyone for anything, a wide variety of applications and services are therefore envisioned. This naturally calls for a more flexible system to support. Moreover, the demand for drastically increased data traffic, as well as the fact of spectrum scarcity, would eventually force future spectrum access to a more dynamic fashion. For addressing the challenges, a powerful and flexible physical layer technology must be prepared, which naturally brings us to the question whether the legacy of the OFDM system can still fit in this context. In fact, during the past years, extensive research effort has been made in this area and several enhanced alternatives have been reported in the literature. Nevertheless, up to date, all of the proposed schemes have advantages and disadvantages. In this paper, we give a detailed analysis on these well-known schemes from different aspects and point out their open issues. Then, we propose a new scheme that aims to maximally overcome the identified drawbacks of its predecessors while still trying to keep their advantages. Simulation results illustrate the improvement achieved by our proposal.

Conformational Flexibility Enables the Function of a BECN1 Region Essential for Starvation-Mediated Autophagy

DOE PAGES

Mei, Yang; Ramanathan, Arvind; Glover, Karen; ...

2016-03-03

BECN1 is essential for autophagy, a critical eukaryotic cellular homeostasis pathway. Here in this study, we delineate a highly conserved BECN1 domain located between previously characterized BH3 and coiled-coil domains and elucidate its structure and role in autophagy. The 2.0 Å sulfur-single-wavelength anomalous dispersion X-ray crystal structure of this domain demonstrates that its N-terminal half is unstructured while its C-terminal half is helical; hence, we name it the flexible helical domain (FHD). Circular dichroism spectroscopy, double electron–electron resonance–electron paramagnetic resonance, and small-angle X-ray scattering (SAXS) analyses confirm that the FHD is partially disordered, even in the context of adjacent BECN1more » domains. Molecular dynamic simulations fitted to SAXS data indicate that the FHD transiently samples more helical conformations. FHD helicity increases in 2,2,2-trifluoroethanol, suggesting it may become more helical upon binding. Finally, cellular studies show that conserved FHD residues are required for starvation-induced autophagy. Thus, the FHD likely undergoes a binding-associated disorder-to-helix transition, and conserved residues critical for this interaction are essential for starvation-induced autophagy.« less

Effects of Physical Activity Intervention on Motor Proficiency and Physical Fitness in Children With ADHD: An Exploratory Study.

PubMed

Pan, Chien-Yu; Chang, Yu-Kai; Tsai, Chia-Liang; Chu, Chia-Hua; Cheng, Yun-Wen; Sung, Ming-Chih

2017-07-01

This study explored how a 12-week simulated developmental horse-riding program (SDHRP) combined with fitness training influenced the motor proficiency and physical fitness of children with ADHD. Twelve children with ADHD received the intervention, whereas 12 children with ADHD and 24 typically developing (TD) children did not. The fitness levels and motor skills of the participants were assessed using standardized tests before and after the 12-week training program. Significant improvements were observed in the motor proficiency, cardiovascular fitness, and flexibility of the ADHD training group following the intervention. Children with ADHD exhibit low levels of motor proficiency and cardiovascular fitness; thus, using the combined 12-week SDHRP and fitness training positively affected children with ADHD.

Dynamic Testing of a Pre-stretched Flexible Tube for Identifying the Factors Affecting Modal Parameter Estimation

NASA Astrophysics Data System (ADS)

Unnikrishnan, Madhusudanan; Rajan, Akash; Basanthvihar Raghunathan, Binulal; Kochupillai, Jayaraj

2017-08-01

Experimental modal analysis is the primary tool for obtaining the fundamental dynamic characteristics like natural frequency, mode shape and modal damping ratio that determine the behaviour of any structure under dynamic loading conditions. This paper discusses about a carefully designed experimental method for calculating the dynamic characteristics of a pre-stretched horizontal flexible tube made of polyurethane material. The factors that affect the modal parameter estimation like the application time of shaker excitation, pause time between successive excitation cycles, averaging and windowing of measured signal, as well as the precautions to be taken during the experiment are explained in detail. The modal parameter estimation is done using MEscopeVESTM software. A finite element based pre-stressed modal analysis of the flexible tube is also done using ANSYS ver.14.0 software. The experimental and analytical results agreed well. The proposed experimental methodology may be extended for carrying out the modal analysis of many flexible structures like inflatables, tires and membranes.

Dynamic Analysis and Control of Lightweight Manipulators with Flexible Parallel Link Mechanisms. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Lee, Jeh Won

1990-01-01

The objective is the theoretical analysis and the experimental verification of dynamics and control of a two link flexible manipulator with a flexible parallel link mechanism. Nonlinear equations of motion of the lightweight manipulator are derived by the Lagrangian method in symbolic form to better understand the structure of the dynamic model. The resulting equation of motion have a structure which is useful to reduce the number of terms calculated, to check correctness, or to extend the model to higher order. A manipulator with a flexible parallel link mechanism is a constrained dynamic system whose equations are sensitive to numerical integration error. This constrained system is solved using singular value decomposition of the constraint Jacobian matrix. Elastic motion is expressed by the assumed mode method. Mode shape functions of each link are chosen using the load interfaced component mode synthesis. The discrepancies between the analytical model and the experiment are explained using a simplified and a detailed finite element model.

The influence of track modelling options on the simulation of rail vehicle dynamics

NASA Astrophysics Data System (ADS)

Di Gialleonardo, Egidio; Braghin, Francesco; Bruni, Stefano

2012-09-01

This paper investigates the effect of different models for track flexibility on the simulation of railway vehicle running dynamics on tangent and curved track. To this end, a multi-body model of the rail vehicle is defined including track flexibility effects on three levels of detail: a perfectly rigid pair of rails, a sectional track model and a three-dimensional finite element track model. The influence of the track model on the calculation of the nonlinear critical speed is pointed out and it is shown that neglecting the effect of track flexibility results in an overestimation of the critical speed by more than 10%. Vehicle response to stochastic excitation from track irregularity is also investigated, analysing the effect of track flexibility models on the vertical and lateral wheel-rail contact forces. Finally, the effect of the track model on the calculation of dynamic forces produced by wheel out-of-roundness is analysed, showing that peak dynamic loads are very sensitive to the track model used in the simulation.

Buckling Instabilities and Complex Dynamics in a Model of Uniflagellar Bacterial Locomotion

NASA Astrophysics Data System (ADS)

Nguyen, Frank; Graham, Michael

2015-11-01

Locomotion of microorganisms at low Reynolds number is a long studied problem. Of particular interest are organisms using a single flagellum to undergo a wide range of motions: pushing, pulling, and tumbling or flicking. Recent experiments have connected the stability of the hook protein, connecting cell motor and flagellum, to deviations from typical straight swimming trajectories. We seek physical explanations to these phenomena by developing a computationally inexpensive, rigid-body dynamic model of a uniflagellated organism with a flexible hook connection that captures the fundamental dynamics, kinematics, and configurations. Furthermore, the model addresses the effects of hook loading and geometry on the stability of the system. Simulations with low hook flexibility produce the classic straight trajectory, but a large flexibility produces helical trajectories, leading to directional changes when coupled with transient hook stiffening. Minima for critical flexibilities are found in certain subsets of parameter space, implying preferred geometries for certain swimming dynamics. The model verifies proposed mechanisms for swimming in various modes and highlights the role of flexibility in the biology of real organisms and the engineering of artificial microswimmers. This work was supported by NSF grant PHY-1304942.

Reference standards to assess physical fitness of children and adolescents of Brazil: an approach to the students of the Lake Itaipú region-Brazil.

PubMed

Hobold, Edilson; Pires-Lopes, Vitor; Gómez-Campos, Rossana; de Arruda, Miguel; Andruske, Cynthia Lee; Pacheco-Carrillo, Jaime; Cossio-Bolaños, Marco Antonio

2017-01-01

The importance of assessing body fat variables and physical fitness tests plays an important role in monitoring the level of activity and physical fitness of the general population. The objective of this study was to develop reference norms to evaluate the physical fitness aptitudes of children and adolescents based on age and sex from the lake region of Itaipú, Brazil. A descriptive cross-sectional study was carried out with 5,962 students (2,938 males and 3,024 females) with an age range of 6.0 and 17.9 years. Weight (kg), height (cm), and triceps (mm), and sub-scapular skinfolds (mm) were measured. Body Mass Index (BMI kg/m 2 ) was calculated. To evaluate the four physical fitness aptitude dimensions (morphological, muscular strength, flexibility, and cardio-respiratory), the following physical education tests were given to the students: sit-and-reach (cm), push-ups (rep), standing long jump (cm), and 20-m shuttle run (m). Females showed greater flexibility in the sit-and-reach test and greater body fat than the males. No differences were found in BMI. Percentiles were created for the four components for the physical fitness aptitudes, BMI, and skinfolds by using the LMS method based on age and sex. The proposed reference values may be used for detecting talents and promoting health in children and adolescents.

Can Programmed or Self-Selected Physical Activity Affect Physical Fitness of Adolescents?

PubMed Central

Neto, Cláudio F.; Neto, Gabriel R.; Araújo, Adenilson T.; Sousa, Maria S. C.; Sousa, Juliana B. C.; Batista, Gilmário R.; Reis, Victor M. M. R.

2014-01-01

The aim of this study was to verify the effects of programmed and self-selected physical activities on the physical fitness of adolescents. High school adolescents, aged between 15 and 17 years, were divided into two experimental groups: a) a self-selected physical activity group (PAS) with 55 students (aged 15.7 ± 0.7 years), who performed physical activities with self-selected rhythm at the following sports: basketball, volleyball, handball, futsal and swimming; and b) a physical fitness training group (PFT) with 53 students (aged 16.0 ± 0.7 years), who performed programmed physical fitness exercises. Both types of activity were developed during 60 min classes. To assess physical fitness the PROESP-BR protocol was used. The statistical analysis was performed by repeated measures ANOVA. The measurements of pre and post-tests showed significantly different values after PFT in: 9 minute running test, medicine ball throw, horizontal jump, abdominal endurance, running speed and flexibility. After PAS differences were detected in abdominal endurance, agility, running speed and flexibility. The intervention with programmed physical activity promoted more changes in the physical abilities; however, in the self-selected program, agility was improved probably because of the practice of sports. Therefore, physical education teachers can use PFT to improve cardiorespiratory fitness and power of lower and upper limbs and PAS to improve agility of high school adolescents. PMID:25713652

Active Transportation to and on Campus is Associated With Objectively Measured Fitness Outcomes Among College Students.

PubMed

Bopp, Melissa; Bopp, Christopher; Schuchert, Megan

2015-03-01

Active transportation (AT) has been associated with positive health outcomes, yet limited research has addressed this with college students, a population at-risk for inactivity. The purpose of this study was to examine the relationship between AT behavior and objectively measured fitness outcomes. A volunteer, convenience sample (n = 299) of college students from a large northeastern university completed a survey about their AT habits to and on campus and psychosocial constructs related to AT and participated in a laboratory-based fitness assessment (cardiovascular endurance, muscular strength and endurance, flexibility, body composition).Off-campus students were dichotomized as nonactive (0-1 AT trips/day) or active travelers (> 1 AT trips/day) to campus; t-tests compared nonactive and active travelers for psychosocial and fitness variables. Students were 56.3% male, 79.2% non-Hispanic White, and primarily living off-campus (87%). Most students (n = 177, 59.2%) reported active travel between classes. Off-campus students were primarily active travelers (76.1%). Active travelers to campus had greater cardiovascular fitness (P = .005), were more flexible (P = .006) and had lower systolic blood pressure (P = .05) compared with nonactive travelers. This study documents a relationship between AT behavior and objectively measured fitness among college students and provides a rationale for targeting this behavior as a method for improving health outcomes.

Uncertain dynamic analysis for rigid-flexible mechanisms with random geometry and material properties

NASA Astrophysics Data System (ADS)

Wu, Jinglai; Luo, Zhen; Zhang, Nong; Zhang, Yunqing; Walker, Paul D.

2017-02-01

This paper proposes an uncertain modelling and computational method to analyze dynamic responses of rigid-flexible multibody systems (or mechanisms) with random geometry and material properties. Firstly, the deterministic model for the rigid-flexible multibody system is built with the absolute node coordinate formula (ANCF), in which the flexible parts are modeled by using ANCF elements, while the rigid parts are described by ANCF reference nodes (ANCF-RNs). Secondly, uncertainty for the geometry of rigid parts is expressed as uniform random variables, while the uncertainty for the material properties of flexible parts is modeled as a continuous random field, which is further discretized to Gaussian random variables using a series expansion method. Finally, a non-intrusive numerical method is developed to solve the dynamic equations of systems involving both types of random variables, which systematically integrates the deterministic generalized-α solver with Latin Hypercube sampling (LHS) and Polynomial Chaos (PC) expansion. The benchmark slider-crank mechanism is used as a numerical example to demonstrate the characteristics of the proposed method.

A flexible metal–organic framework: Guest molecules controlled dynamic gas adsorption

DOE PAGES

Mahurin, Shannon Mark; Li, Man -Rong; Wang, Hailong; ...

2015-04-13

A flexible metal–organic framework (MOF) of [Zn 3(btca) 2(OH) 2]·(guest) n (H 2btca = 1,2,3-benzotriazole-5-carboxylic acid) that exhibits guest molecule-controlled dynamic gas adsorption is reported in which carbon dioxide molecules rather than N 2, He, and Ar induce a structural transition with a corresponding appearance of additional steps in the isotherms. Physical insights into the dynamic adsorption behaviors of flexible compound 1 were detected by gas adsorption at different temperatures and different pressures and confirmed by Fourier transform infrared spectroscopy and molecular simulations. Interestingly, by taking advantage of the flexible nature inherent to the framework, this MOF material enables highlymore » selective adsorption of CO 2/N 2, CO 2/Ar, and CO 2/He of 36.3, 32.6, and 35.9, respectively, at 298 K. Furthermore, this class of flexible MOFs has potential applications for controlled release, molecular sensing, noble gas separation, smart membranes, and nanotechnological devices.« less

Application of partial differential equation modeling of the control/structural dynamics of flexible spacecraft

NASA Technical Reports Server (NTRS)

Taylor, Lawrence W., Jr.; Rajiyah, H.

1991-01-01

Partial differential equations for modeling the structural dynamics and control systems of flexible spacecraft are applied here in order to facilitate systems analysis and optimization of these spacecraft. Example applications are given, including the structural dynamics of SCOLE, the Solar Array Flight Experiment, the Mini-MAST truss, and the LACE satellite. The development of related software is briefly addressed.

A Stochastic Fractional Dynamics Model of Space-time Variability of Rain

NASA Technical Reports Server (NTRS)

Kundu, Prasun K.; Travis, James E.

2013-01-01

Rainfall varies in space and time in a highly irregular manner and is described naturally in terms of a stochastic process. A characteristic feature of rainfall statistics is that they depend strongly on the space-time scales over which rain data are averaged. A spectral model of precipitation has been developed based on a stochastic differential equation of fractional order for the point rain rate, that allows a concise description of the second moment statistics of rain at any prescribed space-time averaging scale. The model is thus capable of providing a unified description of the statistics of both radar and rain gauge data. The underlying dynamical equation can be expressed in terms of space-time derivatives of fractional orders that are adjusted together with other model parameters to fit the data. The form of the resulting spectrum gives the model adequate flexibility to capture the subtle interplay between the spatial and temporal scales of variability of rain but strongly constrains the predicted statistical behavior as a function of the averaging length and times scales. We test the model with radar and gauge data collected contemporaneously at the NASA TRMM ground validation sites located near Melbourne, Florida and in Kwajalein Atoll, Marshall Islands in the tropical Pacific. We estimate the parameters by tuning them to the second moment statistics of radar data. The model predictions are then found to fit the second moment statistics of the gauge data reasonably well without any further adjustment.

Tunnel flexibility effect on the ground surface acceleration response

NASA Astrophysics Data System (ADS)

Baziar, Mohammad Hassan; Moghadam, Masoud Rabeti; Choo, Yun Wook; Kim, Dong-Soo

2016-09-01

Flexibility of underground structures relative to the surrounding medium, referred to as the flexibility ratio, is an important factor that influences their dynamic interaction. This study investigates the flexibility effect of a box-shaped subway tunnel, resting directly on bedrock, on the ground surface acceleration response using a numerical model verified against dynamic centrifuge test results. A comparison of the ground surface acceleration response for tunnel models with different flexibility ratios revealed that the tunnels with different flexibility ratios influence the acceleration response at the ground surface in different ways. Tunnels with lower flexibility ratios have higher acceleration responses at short periods, whereas tunnels with higher flexibility ratios have higher acceleration responses at longer periods. The effect of the flexibility ratio on ground surface acceleration is more prominent in the high range of frequencies. Furthermore, as the flexibility ratio of the tunnel system increases, the acceleration response moves away from the free field response and shifts towards the longer periods. Therefore, the flexibility ratio of the underground tunnels influences the peak ground acceleration (PGA) at the ground surface, and may need to be considered in the seismic zonation of urban areas.

Flexible Fringe Benefit Plans Save You Money and Keep Employees Happy.

ERIC Educational Resources Information Center

Johnson, Rob

1987-01-01

This fringe benefit plan saves money for both employers and employees, provides a better fit for employees' actual benefit needs, and allows employees to choose options from a menu of benefits. One option is a flexible spending plan. Employees place a portion of their before-tax income into a special account from which allowable expenses are paid…

Cognitive Flexibility through Metastable Neural Dynamics Is Disrupted by Damage to the Structural Connectome.

PubMed

Hellyer, Peter J; Scott, Gregory; Shanahan, Murray; Sharp, David J; Leech, Robert

2015-06-17

Current theory proposes that healthy neural dynamics operate in a metastable regime, where brain regions interact to simultaneously maximize integration and segregation. Metastability may confer important behavioral properties, such as cognitive flexibility. It is increasingly recognized that neural dynamics are constrained by the underlying structural connections between brain regions. An important challenge is, therefore, to relate structural connectivity, neural dynamics, and behavior. Traumatic brain injury (TBI) is a pre-eminent structural disconnection disorder whereby traumatic axonal injury damages large-scale connectivity, producing characteristic cognitive impairments, including slowed information processing speed and reduced cognitive flexibility, that may be a result of disrupted metastable dynamics. Therefore, TBI provides an experimental and theoretical model to examine how metastable dynamics relate to structural connectivity and cognition. Here, we use complementary empirical and computational approaches to investigate how metastability arises from the healthy structural connectome and relates to cognitive performance. We found reduced metastability in large-scale neural dynamics after TBI, measured with resting-state functional MRI. This reduction in metastability was associated with damage to the connectome, measured using diffusion MRI. Furthermore, decreased metastability was associated with reduced cognitive flexibility and information processing. A computational model, defined by empirically derived connectivity data, demonstrates how behaviorally relevant changes in neural dynamics result from structural disconnection. Our findings suggest how metastable dynamics are important for normal brain function and contingent on the structure of the human connectome. Copyright © 2015 the authors 0270-6474/15/359050-14$15.00/0.

Role of active site rigidity in activity: MD simulation and fluorescence study on a lipase mutant.

PubMed

Kamal, Md Zahid; Mohammad, Tabrez Anwar Shamim; Krishnamoorthy, G; Rao, Nalam Madhusudhana

2012-01-01

Relationship between stability and activity of enzymes is maintained by underlying conformational flexibility. In thermophilic enzymes, a decrease in flexibility causes low enzyme activity while in less stable proteins such as mesophiles and psychrophiles, an increase in flexibility is associated with enhanced enzyme activity. Recently, we identified a mutant of a lipase whose stability and activity were enhanced simultaneously. In this work, we probed the conformational dynamics of the mutant and the wild type lipase, particularly flexibility of their active site using molecular dynamic simulations and time-resolved fluorescence techniques. In contrast to the earlier observations, our data show that active site of the mutant is more rigid than wild type enzyme. Further investigation suggests that this lipase needs minimal reorganization/flexibility of active site residues during its catalytic cycle. Molecular dynamic simulations suggest that catalytically competent active site geometry of the mutant is relatively more preserved than wild type lipase, which might have led to its higher enzyme activity. Our study implies that widely accepted positive correlation between conformation flexibility and enzyme activity need not be stringent and draws attention to the possibility that high enzyme activity can still be accomplished in a rigid active site and stable protein structures. This finding has a significant implication towards better understanding of involvement of dynamic motions in enzyme catalysis and enzyme engineering through mutations in active site.

First order coupled dynamic model of flexible space structures with time-varying configurations

NASA Astrophysics Data System (ADS)

Wang, Jie; Li, Dongxu; Jiang, Jianping

2017-03-01

This paper proposes a first order coupled dynamic modeling method for flexible space structures with time-varying configurations for the purpose of deriving the characteristics of the system. The model considers the first time derivative of the coordinate transformation matrix between the platform's body frame and the appendage's floating frame. As a result it can accurately predict characteristics of the system even if flexible appendages rotate with complex trajectory relative to the rigid part. In general, flexible appendages are fixed on the rigid platform or forced to rotate with a slow angular velocity. So only the zero order of the transformation matrix is considered in conventional models. However, due to neglecting of time-varying terms of the transformation matrix, these models introduce severe error when appendages, like antennas, for example, rotate with a fast speed relative to the platform. The first order coupled dynamic model for flexible space structures proposed in this paper resolve this problem by introducing the first time derivative of the transformation matrix. As a numerical example, a central core with a rotating solar panel is considered and the results are compared with those given by the conventional model. It has been shown that the first order terms are of great importance on the attitude of the rigid body and dynamic response of the flexible appendage.

Space robots with flexible appendages: Dynamic modeling, coupling measurement, and vibration suppression

NASA Astrophysics Data System (ADS)

Meng, Deshan; Wang, Xueqian; Xu, Wenfu; Liang, Bin

2017-05-01

For a space robot with flexible appendages, vibrations of flexible structure can be easily excited during both orbit and/or attitude maneuvers of the base and the operation of the manipulators. Hence, the pose (position and attitude) of the manipulator's end-effector will greatly deviate from the desired values, and furthermore, the motion of the manipulator will trigger and exacerbate vibrations of flexible appendages. Given lack of the atmospheric damping in orbit, the vibrations will last for quite a while and cause the on-orbital tasks to fail. We derived the rigid-flexible coupling dynamics of a space robot system with flexible appendages and established a coupling model between the flexible base and the space manipulator. A specific index was defined to measure the coupling degree between the flexible motion of the appendages and the rigid motion of the end-effector. Then, we analyzed the dynamic coupling for different conditions, such as modal displacements, joint angles (manipulator configuration), and mass properties. Moreover, the coupling map was adopted and drawn to represent the coupling motion. Based on this map, a trajectory planning method was addressed to suppress structure vibration. Finally, simulation studies of typical cases were performed, which verified the proposed models and method. This work provides a theoretic basis for the system design, performance evaluation, trajectory planning, and control of such space robots.

Coupled nonlinear aeroelasticity and flight dynamics of fully flexible aircraft

NASA Astrophysics Data System (ADS)

Su, Weihua

This dissertation introduces an approach to effectively model and analyze the coupled nonlinear aeroelasticity and flight dynamics of highly flexible aircraft. A reduced-order, nonlinear, strain-based finite element framework is used, which is capable of assessing the fundamental impact of structural nonlinear effects in preliminary vehicle design and control synthesis. The cross-sectional stiffness and inertia properties of the wings are calculated along the wing span, and then incorporated into the one-dimensional nonlinear beam formulation. Finite-state unsteady subsonic aerodynamics is used to compute airloads along lifting surfaces. Flight dynamic equations are then introduced to complete the aeroelastic/flight dynamic system equations of motion. Instead of merely considering the flexibility of the wings, the current work allows all members of the vehicle to be flexible. Due to their characteristics of being slender structures, the wings, tail, and fuselage of highly flexible aircraft can be modeled as beams undergoing three dimensional displacements and rotations. New kinematic relationships are developed to handle the split beam systems, such that fully flexible vehicles can be effectively modeled within the existing framework. Different aircraft configurations are modeled and studied, including Single-Wing, Joined-Wing, Blended-Wing-Body, and Flying-Wing configurations. The Lagrange Multiplier Method is applied to model the nodal displacement constraints at the joint locations. Based on the proposed models, roll response and stability studies are conducted on fully flexible and rigidized models. The impacts of the flexibility of different vehicle members on flutter with rigid body motion constraints, flutter in free flight condition, and roll maneuver performance are presented. Also, the static stability of the compressive member of the Joined-Wing configuration is studied. A spatially-distributed discrete gust model is incorporated into the time simulation of the framework. Gust responses of the Flying-Wing configuration subject to stall effects are investigated. A bilinear torsional stiffness model is introduced to study the skin wrinkling due to large bending curvature of the Flying-Wing. The numerical studies illustrate the improvements of the existing reduced-order formulation with new capabilities of both structural modeling and coupled aeroelastic and flight dynamic analysis of fully flexible aircraft.

Eurofit Special: European Fitness Battery Score Variation among Individuals with Intellectual Disabilities

ERIC Educational Resources Information Center

Skowronski, Waldemar; Horvat, Michael; Nocera, Joe; Roswal, Glenn; Croce, Ron

2009-01-01

The Eurofit Special Test is a battery of motor fitness tests resulting from a 10-year project of the Committee of Experts for Sports Research and is comprised of strength, speed, flexibility, and balance. The purpose of this study was to investigate whether the Eurofit Special was able to distinguish variations in functioning among individuals…

Introduction to Architectures: HSCB Information - What It Is and How It Fits (or Doesn’t Fit)

DTIC Science & Technology

2010-10-01

Simulation Interoperability Workshop, 01E- SIW -080 [15] Barry G. Silverman, Gnana Gharathy, Kevin O’Brien, Jason Cornwell, “Human Behavior Models for Agents...Workshop, 10F- SIW -023, September 2010. [17] Christiansen, John H., “A flexible object-based software framework for modelling complex systems with

Age, Sex, and Body Composition as Predictors of Children's Performance on Basic Motor Abilities and Health-Related Fitness Items.

ERIC Educational Resources Information Center

Pissanos, Becky W.; And Others

1983-01-01

Step-wise linear regressions were used to relate children's age, sex, and body composition to performance on basic motor abilities including balance, speed, agility, power, coordination, and reaction time, and to health-related fitness items including flexibility, muscle strength and endurance and cardiovascular functions. Eighty subjects were in…

Association of School Environment and After-School Physical Activity with Health-Related Physical Fitness among Junior High School Students in Taiwan

PubMed Central

Lo, Kai-Yang; Wu, Min-Chen; Tung, Shu-Chin; Hsieh, City C.; Yao, Hsueh-Hua; Ho, Chien-Chang

2017-01-01

The relationship between students’ school environment and exercise habits is complex, and is affected by numerous factors. However, the few studies that have been conducted on this relationship have reported inconsistent results, especially regarding Taiwanese students. We conducted this cross-sectional study to investigate the association of school environment and after-school physical activity with health-related physical fitness in Taiwanese adolescents. Data were drawn from a national survey conducted by the Ministry of Education in Taiwan in 2008 of health-related physical fitness measurements among junior high school students (649,442 total) in grades seven to nine. School environment (level of urbanization, school size, presence of sports field or gymnasium) and after-school physical activity were assessed for their association with adolescents’ physical fitness measurements (body mass index (BMI), bent-leg sit-ups, 800-/1600-m run, sit-and-reach, standing long jump). Urban boys and girls perform significantly better in muscle strength and endurance, cardiorespiratory endurance, flexibility, and explosive power; girls from rural areas exhibited significantly worse scores in body composition. Boys from large-size schools performed the worst in cardiorespiratory endurance, flexibility, and explosive power; whereas girls from large-size schools performed the worst in muscle strength, muscle endurance, and explosive power, but had the best score for body composition. However, the differences in body composition of boys from large-, medium-, and small- size schools did not reach a statistically significant level. Adolescents of both genders in schools with a sports field or gymnasium exhibited significantly better in muscle strength and endurance, cardiorespiratory endurance, and explosive power. Boys in schools with a sports field or gymnasium had significantly better body composition; girls in schools with sports field or gymnasium differed significantly in flexibility. Adolescents of both genders who participated in physical activity after school had significantly better body composition, cardiorespiratory endurance, and flexibility. Boys who participated in physical activity after school significantly differed in explosive power, whereas girls who participated in physical activity after school exhibited significantly better flexibility. Thus, the current study demonstrated that some factors, including urbanization (school location in rural or urban areas), school size, school facility provision (school with or without sports fields or gymnasiums), and after-school physical activity participation are more important than others in shaping adolescents’ physical fitness in Taiwan; meanwhile, these association patterns differed by gender. PMID:28098836

Association of School Environment and After-School Physical Activity with Health-Related Physical Fitness among Junior High School Students in Taiwan.

PubMed

Lo, Kai-Yang; Wu, Min-Chen; Tung, Shu-Chin; Hsieh, City C; Yao, Hsueh-Hua; Ho, Chien-Chang

2017-01-15

The relationship between students' school environment and exercise habits is complex, and is affected by numerous factors. However, the few studies that have been conducted on this relationship have reported inconsistent results, especially regarding Taiwanese students. We conducted this cross-sectional study to investigate the association of school environment and after-school physical activity with health-related physical fitness in Taiwanese adolescents. Data were drawn from a national survey conducted by the Ministry of Education in Taiwan in 2008 of health-related physical fitness measurements among junior high school students (649,442 total) in grades seven to nine.School environment (level of urbanization, school size, presence of sports field or gymnasium) and after-school physical activity were assessed for their association with adolescents' physical fitness measurements (body mass index (BMI), bent-leg sit-ups, 800-/1600-m run, sit-and-reach, standing long jump). Urban boys and girls perform significantly better in muscle strength and endurance, cardiorespiratory endurance, flexibility, and explosive power; girls from rural areas exhibited significantly worse scores in body composition. Boys from large-size schools performed the worst in cardiorespiratory endurance, flexibility, and explosive power; whereas girls from large-size schools performed the worst in muscle strength, muscle endurance, and explosive power, but had the best score for body composition. However, the differences in body composition of boys from large-, medium-, and small- size schools did not reach a statistically significant level. Adolescents of both genders in schools with a sports field or gymnasium exhibited significantly better in muscle strength and endurance, cardiorespiratory endurance, and explosive power. Boys in schools with a sports field or gymnasium had significantly better body composition; girls in schools with sports field or gymnasium differed significantly in flexibility. Adolescents of both genders who participated in physical activity after school had significantly better body composition, cardiorespiratory endurance, and flexibility. Boys who participated in physical activity after school significantly differed in explosive power, whereas girls who participated in physical activity after school exhibited significantly better flexibility. Thus, the current study demonstrated that some factors, including urbanization (school location in rural or urban areas), school size, school facility provision (school with or without sports fields or gymnasiums), and after-school physical activity participation are more important than others in shaping adolescents' physical fitness in Taiwan; meanwhile, these association patterns differed by gender.

The young skater.

PubMed

Smith, A D

2000-10-01

Figure skating is one of the best lifetime sports. Participants may skate alone or with a group, recreationally or competitively, at all ages and at all skill levels. As a sport that improves physical fitness, skating builds strength, flexibility, and cardiopulmonary endurance. As a weight-bearing or high-impact activity, it is one of the best sports for increasing bone mineral density and perhaps for preventing osteoporosis. At least half of all competitive figure skating injuries appear preventable. Boots should be as flexible as the skater can control and should be carefully fitted. Normal flexibility of lower extremity muscles, especially in the growing athlete, markedly decreases the incidence of overuse symptoms of the knee. Core body strength is critical for controlling high-impact jump landings and decreasing injuries to the spine, pelvis, and hip girdle. Adequate shoulder strength is required for pair skaters and ice dancers. A well-designed off-ice training program decreases injury incidence and enhances performance. Assisting these dedicated athletes is truly rewarding as they train and compete at their highest potential, with passion for their sport.

A dynamic scheduling algorithm for singe-arm two-cluster tools with flexible processing times

NASA Astrophysics Data System (ADS)

Li, Xin; Fung, Richard Y. K.

2018-02-01

This article presents a dynamic algorithm for job scheduling in two-cluster tools producing multi-type wafers with flexible processing times. Flexible processing times mean that the actual times for processing wafers should be within given time intervals. The objective of the work is to minimize the completion time of the newly inserted wafer. To deal with this issue, a two-cluster tool is decomposed into three reduced single-cluster tools (RCTs) in a series based on a decomposition approach proposed in this article. For each single-cluster tool, a dynamic scheduling algorithm based on temporal constraints is developed to schedule the newly inserted wafer. Three experiments have been carried out to test the dynamic scheduling algorithm proposed, comparing with the results the 'earliest starting time' heuristic (EST) adopted in previous literature. The results show that the dynamic algorithm proposed in this article is effective and practical.

Linking family dynamics and the mental health of Colombian dementia caregivers.

PubMed

Sutter, Megan; Perrin, Paul B; Chang, Yu-Ping; Hoyos, Guillermo Ramirez; Buraye, Jaqueline Arabia; Arango-Lasprilla, Juan Carlos

2014-02-01

This cross-sectional, quantitative, self-report study examined the relationship between family dynamics (cohesion, flexibility, pathology/ functioning, communication, family satisfaction, and empathy) and mental health (depression, burden, stress, and satisfaction with life [SWL]) in 90 dementia caregivers from Colombia. Hierarchical multiple regressions controlling for caregiver demographics found that family dynamics were significantly associated with caregiver depression, stress, and SWL and marginally associated with burden. Within these regressions, empathy was uniquely associated with stress; flexibility with depression and marginally with SWL; and family communication marginally with burden and stress. Nearly all family dynamic variables were bivariately associated with caregiver mental health variables, such that caregivers had stronger mental health when their family dynamics were healthy. Family-systems interventions in global regions with high levels of familism like that in the current study may improve family empathy, flexibility, and communication, thereby producing better caregiver mental health and better informal care for people with dementia.

Slew maneuvers of Spacecraft Control Laboratory Experiment (SCOLE)

NASA Technical Reports Server (NTRS)

Kakad, Yogendra P.

1992-01-01

This is the final report on the dynamics and control of slew maneuvers of the Spacecraft Control Laboratory Experiment (SCOLE) test facility. The report documents the basic dynamical equation derivations for an arbitrary large angle slew maneuver as well as the basic decentralized slew maneuver control algorithm. The set of dynamical equations incorporate rigid body slew maneuver and three dimensional vibrations of the complete assembly comprising the rigid shuttle, the flexible beam, and the reflector with an offset mass. The analysis also includes kinematic nonlinearities of the entire assembly during the maneuver and the dynamics of the interactions between the rigid shuttle and the flexible appendage. The equations are simplified and evaluated numerically to include the first ten flexible modes to yield a model for designing control systems to perform slew maneuvers. The control problem incorporates the nonlinear dynamical equations and is expressed in terms of a two point boundary value problem.

Acrylonitrile Quenching of Trp Phosphorescence in Proteins: A Probe of the Internal Flexibility of the Globular Fold

PubMed Central

Strambini, Giovanni B.; Gonnelli, Margherita

2010-01-01

Quenching of Trp phosphorescence in proteins by diffusion of solutes of various molecular sizes unveils the frequency-amplitude of structural fluctuations. To cover the sizes gap between O2 and acrylamide, we examined the potential of acrylonitrile to probe conformational flexibility of proteins. The distance dependence of the through-space acrylonitrile quenching rate was determined in a glass at 77 K, with the indole analog 2-(3-indoyl) ethyl phenyl ketone. Intensity and decay kinetics data were fitted to a rate, k(r) = k0 exp[−(r − r0)/re], with an attenuation length re = 0.03 nm and a contact rate k0 = 3.6 × 1010 s−1. At ambient temperature, the bimolecular quenching rate constant (kq) was determined for a series of proteins, appositely selected to test the importance of factors such as the degree of Trp burial and structural rigidity. Relative to kq = 1.9 × 109 M−1s−1 for free Trp in water, in proteins kq ranged from 6.5 × 106 M−1s−1 for superficial sites to 1.3 × 102 M−1s−1 for deep cores. The short-range nature of the interaction and the direct correlation between kq and structural flexibility attest that in the microsecond-second timescale of phosphorescence acrylonitrile readily penetrates even compact protein cores and exhibits significant sensitivity to variations in dynamical structure of the globular fold. PMID:20682273

Research on Equivalent Tests of Dynamics of On-orbit Soft Contact Technology Based on On-Orbit Experiment Data

NASA Astrophysics Data System (ADS)

Yang, F.; Dong, Z. H.; Ye, X.

2018-05-01

Currently, space robots have been become a very important means of space on-orbit maintenance and support. Many countries are taking deep research and experiment on this. Because space operation attitude is very complicated, it is difficult to model them in research lab. This paper builds up a complete equivalent experiment framework according to the requirement of proposed space soft-contact technology. Also, this paper carries out flexible multi-body dynamics parameters verification for on-orbit soft-contact mechanism, which combines on-orbit experiment data, the built soft-contact mechanism equivalent model and flexible multi-body dynamics equivalent model that is based on KANE equation. The experiment results approve the correctness of the built on-orbit soft-contact flexible multi-body dynamics.

Depression symptoms are associated with key health outcomes in women with fibromyalgia: a cross-sectional study.

PubMed

Del Pozo-Cruz, Jesús; Alfonso-Rosa, Rosa M; Castillo-Cuerva, Alejandro; Sañudo, Borja; Nolan, Paul; Del Pozo-Cruz, Borja

2017-07-01

To analyze the association between depression severity and other fibromyalgia- (FM) related symptoms such as pain, fatigue, sleep problems, severity of the disease, activity pattern, functional capacity and quality of life. The sample included 105 Spanish women with FM. Quality of life was assessed by means of the EQ-5D and symptom severity by the Fibromyalgia Impact Questionnaire. Pain, fatigue and unrestful sleep problems were assessed using 0-10 Visual Analog Scales. Activity patterns were determined by using the International Physical Activity Questionnaire while a battery of standardized field-based functional capacity tests was used to assess cardiorespiratory fitness, muscular strength, flexibility, agility and static and dynamic balance. Depression level was assessed and categorized according to the Beck Depression Inventory. Sixty-two percent of the participants were depressed. Depressed patients exhibited higher pain, fatigue level, sleep problems and severity of the symptoms, reduced levels of lower limb strength and physical activity time and worse quality of life when compared with non-depressed patients (P < 0.05). A negative relationship was found between total minutes of physical activity (P = 0.001) and caloric expenditure (P = 0.026), lower flexibility (P = 0.005), hand grip strength (P = 0.026) and lower limb strength (P < 0.001). A positive relationship was detected between depression and total sitting time (P = 0.018). These results were maintained when correlations were adjusted for body mass index. Depressed women with FM exhibited higher symptom severity and reported worse physical fitness and quality of life than their non-depressed peers. © 2015 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

Inspiration from nature: dynamic modelling of the musculoskeletal structure of the seahorse tail.

PubMed

Praet, Tomas; Adriaens, Dominique; Van Cauter, Sofie; Masschaele, Bert; De Beule, Matthieu; Verhegghe, Benedict

2012-10-01

Technological advances are often inspired by nature, considering that engineering is frequently faced by the same challenges as organisms in nature. One such interesting challenge is creating a structure that is at the same time stiff in a certain direction, yet flexible in another. The seahorse tail combines both radial stiffness and bending flexibility in a particularly elegant way: even though the tail is covered in a protective armour, it still shows sufficient flexibility to fully function as a prehensile organ. We therefore study the complex mechanics and dynamics of the musculoskeletal system of the seahorse tail from an engineering point of view. The seahorse tail derives its combination of flexibility and resilience from a chain of articulating skeletal segments. A versatile dynamic model of those segments was constructed, on the basis of automatic recognition of joint positions and muscle attachments. Both muscle structures that are thought to be responsible for ventral and ventral-lateral tail bending, namely the median ventral muscles and the hypaxial myomere muscles, were included in the model. Simulations on the model consist mainly of dynamic multi-body simulations. The results show that the sequential structure of uniformly shaped bony segments can remain flexible because of gliding joints that connect the corners of the segments. Radial stiffness on the other hand is obtained through the support that the central vertebra provides to the tail plating. Such insights could help in designing biomedical instruments that specifically require both high bending flexibility and radial stiffness (e.g. flexible stents and steerable catheters). Copyright © 2012 John Wiley & Sons, Ltd.

Large planar maneuvers for articulated flexible manipulators

NASA Technical Reports Server (NTRS)

Huang, Jen-Kuang; Yang, Li-Farn

1988-01-01

An articulated flexible manipulator carried on a translational cart is maneuvered by an active controller to perform certain position control tasks. The nonlinear dynamics of the articulated flexible manipulator are derived and a transformation matrix is formulated to localize the nonlinearities within the inertia matrix. Then a feedback linearization scheme is introduced to linearize the dynamic equations for controller design. Through a pole placement technique, a robust controller design is obtained by properly assigning a set of closed-loop desired eigenvalues to meet performance requirements. Numerical simulations for the articulated flexible manipulators are given to demonstrate the feasibility and effectiveness of the proposed position control algorithms.

Dynamic Appliances Scheduling in Collaborative MicroGrids System

PubMed Central

Bilil, Hasnae; Aniba, Ghassane; Gharavi, Hamid

2017-01-01

In this paper a new approach which is based on a collaborative system of MicroGrids (MG’s), is proposed to enable household appliance scheduling. To achieve this, appliances are categorized into flexible and non-flexible Deferrable Loads (DL’s), according to their electrical components. We propose a dynamic scheduling algorithm where users can systematically manage the operation of their electric appliances. The main challenge is to develop a flattening function calculus (reshaping) for both flexible and non-flexible DL’s. In addition, implementation of the proposed algorithm would require dynamically analyzing two successive multi-objective optimization (MOO) problems. The first targets the activation schedule of non-flexible DL’s and the second deals with the power profiles of flexible DL’s. The MOO problems are resolved by using a fast and elitist multi-objective genetic algorithm (NSGA-II). Finally, in order to show the efficiency of the proposed approach, a case study of a collaborative system that consists of 40 MG’s registered in the load curve for the flattening program has been developed. The results verify that the load curve can indeed become very flat by applying the proposed scheduling approach. PMID:28824226

Task-dependent recurrent dynamics in visual cortex

PubMed Central

Tajima, Satohiro; Koida, Kowa; Tajima, Chihiro I; Suzuki, Hideyuki; Aihara, Kazuyuki; Komatsu, Hidehiko

2017-01-01

The capacity for flexible sensory-action association in animals has been related to context-dependent attractor dynamics outside the sensory cortices. Here, we report a line of evidence that flexibly modulated attractor dynamics during task switching are already present in the higher visual cortex in macaque monkeys. With a nonlinear decoding approach, we can extract the particular aspect of the neural population response that reflects the task-induced emergence of bistable attractor dynamics in a neural population, which could be obscured by standard unsupervised dimensionality reductions such as PCA. The dynamical modulation selectively increases the information relevant to task demands, indicating that such modulation is beneficial for perceptual decisions. A computational model that features nonlinear recurrent interaction among neurons with a task-dependent background input replicates the key properties observed in the experimental data. These results suggest that the context-dependent attractor dynamics involving the sensory cortex can underlie flexible perceptual abilities. DOI: http://dx.doi.org/10.7554/eLife.26868.001 PMID:28737487

Biologically plausible learning in recurrent neural networks reproduces neural dynamics observed during cognitive tasks

PubMed Central

Miconi, Thomas

2017-01-01

Neural activity during cognitive tasks exhibits complex dynamics that flexibly encode task-relevant variables. Chaotic recurrent networks, which spontaneously generate rich dynamics, have been proposed as a model of cortical computation during cognitive tasks. However, existing methods for training these networks are either biologically implausible, and/or require a continuous, real-time error signal to guide learning. Here we show that a biologically plausible learning rule can train such recurrent networks, guided solely by delayed, phasic rewards at the end of each trial. Networks endowed with this learning rule can successfully learn nontrivial tasks requiring flexible (context-dependent) associations, memory maintenance, nonlinear mixed selectivities, and coordination among multiple outputs. The resulting networks replicate complex dynamics previously observed in animal cortex, such as dynamic encoding of task features and selective integration of sensory inputs. We conclude that recurrent neural networks offer a plausible model of cortical dynamics during both learning and performance of flexible behavior. DOI: http://dx.doi.org/10.7554/eLife.20899.001 PMID:28230528

Biologically plausible learning in recurrent neural networks reproduces neural dynamics observed during cognitive tasks.

PubMed

Miconi, Thomas

2017-02-23

Neural activity during cognitive tasks exhibits complex dynamics that flexibly encode task-relevant variables. Chaotic recurrent networks, which spontaneously generate rich dynamics, have been proposed as a model of cortical computation during cognitive tasks. However, existing methods for training these networks are either biologically implausible, and/or require a continuous, real-time error signal to guide learning. Here we show that a biologically plausible learning rule can train such recurrent networks, guided solely by delayed, phasic rewards at the end of each trial. Networks endowed with this learning rule can successfully learn nontrivial tasks requiring flexible (context-dependent) associations, memory maintenance, nonlinear mixed selectivities, and coordination among multiple outputs. The resulting networks replicate complex dynamics previously observed in animal cortex, such as dynamic encoding of task features and selective integration of sensory inputs. We conclude that recurrent neural networks offer a plausible model of cortical dynamics during both learning and performance of flexible behavior.

Dynamics of flexible fibers and vesicles in Poiseuille flow at low Reynolds number.

PubMed

Farutin, Alexander; Piasecki, Tomasz; Słowicka, Agnieszka M; Misbah, Chaouqi; Wajnryb, Eligiusz; Ekiel-Jeżewska, Maria L

2016-09-21

The dynamics of flexible fibers and vesicles in unbounded planar Poiseuille flow at low Reynolds number is shown to exhibit similar basic features, when their equilibrium (moderate) aspect ratio is the same and vesicle viscosity contrast is relatively high. Tumbling, lateral migration, accumulation and shape evolution of these two types of flexible objects are analyzed numerically. The linear dependence of the accumulation position on relative bending rigidity, and other universal scalings are derived from the local shear flow approximation.

Modeling and tachometer feedback in the control of an experimental single link flexible structure

NASA Technical Reports Server (NTRS)

Garcia, Ephrahim; Inman, Daniel J.

1990-01-01

In this work a formulation for the modeling of a single link flexible structure will be introduced that includes the effects of dynamic interaction between the actuator and structure. These effects are the rotational modal participation factors for the structure's vibratory motion that occurs at the slewing axis. It will be shown, both theoretically and experimentally, that this dynamic interaction can be advantageous for vibration suppression of the flexible modes of the system during slewing positioning maneuvers.

Spatial operator approach to flexible multibody system dynamics and control

NASA Technical Reports Server (NTRS)

Rodriguez, G.

1991-01-01

The inverse and forward dynamics problems for flexible multibody systems were solved using the techniques of spatially recursive Kalman filtering and smoothing. These algorithms are easily developed using a set of identities associated with mass matrix factorization and inversion. These identities are easily derived using the spatial operator algebra developed by the author. Current work is aimed at computational experiments with the described algorithms and at modelling for control design of limber manipulator systems. It is also aimed at handling and manipulation of flexible objects.

Dynamic switching between semantic and episodic memory systems.

PubMed

Kompus, Kristiina; Olsson, Carl-Johan; Larsson, Anne; Nyberg, Lars

2009-09-01

It has been suggested that episodic and semantic long-term memory systems interact during retrieval. Here we examined the flexibility of memory retrieval in an associative task taxing memories of different strength, assumed to differentially engage episodic and semantic memory. Healthy volunteers were pre-trained on a set of 36 face-name pairs over a 6-week period. Another set of 36 items was shown only once during the same time period. About 3 months after the training period all items were presented in a randomly intermixed order in an event-related fMRI study of face-name memory. Once presented items differentially activated anterior cingulate cortex and a right prefrontal region that previously have been associated with episodic retrieval mode. High-familiar items were associated with stronger activation of posterior cortices and a left frontal region. These findings fit a model of memory retrieval by which early processes determine, on a trial-by-trial basis, if the task can be solved by the default semantic system. If not, there is a dynamic shift to cognitive control processes that guide retrieval from episodic memory.

Sunlight Responsive Thermochromic Window System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Millett, F,A; Byker,H, J

2006-10-27

Pleotint has embarked on a novel approach with our Sunlight Responsive Thermochromic, SRT™, windows. We are integrating dynamic sunlight control, high insulation values and low solar heat gain together in a high performance window. The Pleotint SRT window is dynamic because it reversibly changes light transmission based on thermochromics activated directly by the heating effect of sunlight. We can achieve a window package with low solar heat gain coefficient (SHGC), a low U value and high insulation. At the same time our windows provide good daylighting. Our innovative window design offers architects and building designers the opportunity to choose theirmore » desired energy performance, excellent sound reduction, external pane can be self-cleaning, or a resistance to wind load, blasts, bullets or hurricanes. SRT windows would provide energy savings that are estimated at up to 30% over traditional window systems. Glass fabricators will be able to use existing equipment to make the SRT window while adding value and flexibility to the basic design. Glazing installers will have the ability to fit the windows with traditional methods without wires, power supplies and controllers. SRT windows can be retrofit into existing buildings,« less

Peer 2 peer: efficacy of a course-based peer education intervention to increase physical activity among college students.

PubMed

Boyle, Jennifer; Mattern, Craig O; Lassiter, Jill W; Ritzler, Julia A

2011-01-01

There are few physical activity (PA) interventions in higher education, and they have been only minimally effective. To determine if a course-based, peer education intervention was associated with increases in PA and physical fitness. Participants were 178 students enrolled in a personal health class during the 2007-2008 academic year. A quasi-experimental design was used to assess the effect of the intervention. Repeated measures analysis of covariance was employed to test the impact of the intervention on students' PA, body composition, waist-to-hip ratio, cardiovascular fitness, flexibility, and muscular strength. Women in the treatment group classified as "Inactive" at baseline increased PA, whereas "Inactive" control women had reductions in PA. Women in the treatment group who were "Active" at baseline reduced their waist-to-hip ratio and increased flexibility. There were no differences by treatment group among men. The intervention was effective in improving PA and physical fitness among college women.

Approximation methods for inverse problems involving the vibration of beams with tip bodies

NASA Technical Reports Server (NTRS)

Rosen, I. G.

1984-01-01

Two cubic spline based approximation schemes for the estimation of structural parameters associated with the transverse vibration of flexible beams with tip appendages are outlined. The identification problem is formulated as a least squares fit to data subject to the system dynamics which are given by a hybrid system of coupled ordinary and partial differential equations. The first approximation scheme is based upon an abstract semigroup formulation of the state equation while a weak/variational form is the basis for the second. Cubic spline based subspaces together with a Rayleigh-Ritz-Galerkin approach were used to construct sequences of easily solved finite dimensional approximating identification problems. Convergence results are briefly discussed and a numerical example demonstrating the feasibility of the schemes and exhibiting their relative performance for purposes of comparison is provided.

Communication: Fitting potential energy surfaces with fundamental invariant neural network

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shao, Kejie; Chen, Jun; Zhao, Zhiqiang

A more flexible neural network (NN) method using the fundamental invariants (FIs) as the input vector is proposed in the construction of potential energy surfaces for molecular systems involving identical atoms. Mathematically, FIs finitely generate the permutation invariant polynomial (PIP) ring. In combination with NN, fundamental invariant neural network (FI-NN) can approximate any function to arbitrary accuracy. Because FI-NN minimizes the size of input permutation invariant polynomials, it can efficiently reduce the evaluation time of potential energy, in particular for polyatomic systems. In this work, we provide the FIs for all possible molecular systems up to five atoms. Potential energymore » surfaces for OH{sub 3} and CH{sub 4} were constructed with FI-NN, with the accuracy confirmed by full-dimensional quantum dynamic scattering and bound state calculations.« less

Discrete and continuous dynamics modeling of a mass moving on a flexible structure

NASA Technical Reports Server (NTRS)

Herman, Deborah Ann

1992-01-01

A general discrete methodology for modeling the dynamics of a mass that moves on the surface of a flexible structure is developed. This problem was motivated by the Space Station/Mobile Transporter system. A model reduction approach is developed to make the methodology applicable to large structural systems. To validate the discrete methodology, continuous formulations are also developed. Three different systems are examined: (1) simply-supported beam, (2) free-free beam, and (3) free-free beam with two points of contact between the mass and the flexible beam. In addition to validating the methodology, parametric studies were performed to examine how the system's physical properties affect its dynamics.

Dynamic characteristics of a variable-mass flexible missile: Dynamics of a two-stage variable-mass flexible rocket

NASA Technical Reports Server (NTRS)

Meirovitch, L.; Bankovskis, J.

1969-01-01

The dynamic characteristics of two-stage slender elastic body were investigated. The first stage, containing a solid-fuel rocket, possesses variable mass while the second stage, envisioned as a flexible case, contains packaged instruments of constant mass. The mathematical formulation was in terms of vector equations of motion transformed by a variational principle into sets of scalar differential equations in terms of generalized coordinates. Solutions to the complete equations were obtained numerically by means of finite difference techniques. The problem has been programmed in the FORTRAN 4 language and solved on an IBM 360/50 computer. Results for limited cases are presented showing the nature of the solutions.

Flexible Space-Filling Designs for Complex System Simulations

DTIC Science & Technology

2013-06-01

interior of the experimental region and cannot fit higher-order models. We present a genetic algorithm that constructs space-filling designs with...Computer Experiments, Design of Experiments, Genetic Algorithm , Latin Hypercube, Response Surface Methodology, Nearly Orthogonal 15. NUMBER OF PAGES 147...experimental region and cannot fit higher-order models. We present a genetic algorithm that constructs space-filling designs with minimal correlations

Running Mileage, Movement Mileage, and Fitness in Male U.S. Navy Recruits

DTIC Science & Technology

2001-01-01

discretion over the ditioning (flexibility, aerobic activity, and calisthenics ), amount of running each division completed. In the log close-order drill...DISCUSSION included movement mileage, run mileage, calisthenics , and task-specific training maneuvers. The aerobic fitness of male naval recruits...Burger and col- acdpyia riigrgmnta nlddmdrtmxalues (8)veriffort, 1.5-mi timedruntescurgter mand col- cardiovascular activity, calisthenics , and

The Construction of a Motor Fitness Test Battery for Boys in the Lower Elementary Grades.

ERIC Educational Resources Information Center

DiNucci, James M.; Shore, John Roger

In order to construct a scientifically designed evaluative instrument to assess the motor fitness of boys in the primary grades, 30 test items purported to measure muscular strength, muscular endurance, cardiovascular endurance, power, speed, agility, flexibility, and balance were administered to an incidental sample of 238 boys ages 6 to 9 years.…

Behavioural adaptations of two sympatric sandhoppers living on a mesotidal European Atlantic sandy beach

NASA Astrophysics Data System (ADS)

Bessa, Filipa; Marques, João Carlos; Scapini, Felicita

2014-06-01

Behavioural adaptations of supralittoral species on sandy beaches are expressed as responses to environmental changes and constitute a key factor in their survival and evolution. Two sympatric talitrid amphipods (Talitrus saltator and Britorchestia brito) from a mesotidal exposed sandy beach on the European Atlantic coast (Portugal) were compared as regards orientation and littoral zonation patterns under natural conditions. Orientation experiments were carried out during spring and summer 2011 and 2012 at Quiaios beach, a highly dynamic exposed sandy beach. Multiple regression models were fitted to the angular data and the environmental effects on orientation were investigated for each species. Both talitrids were shown to be well orientated towards the shoreline and finely adapted to the mesotidal environment but a different use of local cues and climatic features between the two species was apparent. T. saltator showed a lower precision in the orientation performance (with a bimodal distribution sea- and land-wards), with less dependence on the sun cues and higher dependence on climatic features. In addition, the zonation of T. saltator was across the land-sea axis during both seasons. For B. brito the landscape vision, sun visibility and the tidal range enhanced the orientation to the shoreline. On this mesotidal Atlantic beach, T. saltator appeared to have a more flexible orientation with respect to B. brito, which appeared to be more dependent on the conditions offered by the intertidal zone, a behaviour confirmed by its restricted zonation below the high tide mark. Consequently, T. saltator showed a more flexible behaviour that may be considered an important evolutionary adaptation to dynamic and mesotidal sandy beaches.

Evaluation of anthropometric parameters and physical fitness in elderly Japanese.

PubMed

Miyatake, Nobuyuki; Miyachi, Motohiko; Tabata, Izumi; Numata, Takeyuki

2012-01-01

We evaluated anthropometric parameters and physical fitness in elderly Japanese. A total of 2,106 elderly Japanese (749 men and 1,357 women), aged 60-79 years, were enrolled in a cross-sectional investigation study. Anthropometric parameters and physical fitness, i.e., muscle strength and flexibility, were measured. Of the 2,106 subjects, 569 subjects (302 men and 267 women) were further evaluated for aerobic exercise level, using the ventilatory threshold (VT). Muscle strength in subjects in their 70s was significantly lower than that in subjects in their 60s in both sexes. Two hundred and twenty-nine men (30.6%) and 540 women (39.8%) were taking no medications. In men, anthropometric parameters were significantly lower and muscle strength, flexibility, and work rate at VT were significantly higher in subjects without medications than these values in subjects with medications. In women, body weight, body mass index (BMI), and abdominal circumference were significantly lower, and muscle strength was significantly higher in subjects without medications than these values in subjects with medications. This mean value may provide a useful database for evaluating anthropometric parameters and physical fitness in elderly Japanese subjects.

Protein flexibility in the light of structural alphabets

PubMed Central

Craveur, Pierrick; Joseph, Agnel P.; Esque, Jeremy; Narwani, Tarun J.; Noël, Floriane; Shinada, Nicolas; Goguet, Matthieu; Leonard, Sylvain; Poulain, Pierre; Bertrand, Olivier; Faure, Guilhem; Rebehmed, Joseph; Ghozlane, Amine; Swapna, Lakshmipuram S.; Bhaskara, Ramachandra M.; Barnoud, Jonathan; Téletchéa, Stéphane; Jallu, Vincent; Cerny, Jiri; Schneider, Bohdan; Etchebest, Catherine; Srinivasan, Narayanaswamy; Gelly, Jean-Christophe; de Brevern, Alexandre G.

2015-01-01

Protein structures are valuable tools to understand protein function. Nonetheless, proteins are often considered as rigid macromolecules while their structures exhibit specific flexibility, which is essential to complete their functions. Analyses of protein structures and dynamics are often performed with a simplified three-state description, i.e., the classical secondary structures. More precise and complete description of protein backbone conformation can be obtained using libraries of small protein fragments that are able to approximate every part of protein structures. These libraries, called structural alphabets (SAs), have been widely used in structure analysis field, from definition of ligand binding sites to superimposition of protein structures. SAs are also well suited to analyze the dynamics of protein structures. Here, we review innovative approaches that investigate protein flexibility based on SAs description. Coupled to various sources of experimental data (e.g., B-factor) and computational methodology (e.g., Molecular Dynamic simulation), SAs turn out to be powerful tools to analyze protein dynamics, e.g., to examine allosteric mechanisms in large set of structures in complexes, to identify order/disorder transition. SAs were also shown to be quite efficient to predict protein flexibility from amino-acid sequence. Finally, in this review, we exemplify the interest of SAs for studying flexibility with different cases of proteins implicated in pathologies and diseases. PMID:26075209

A class of stabilizing controllers for flexible multibody systems

NASA Technical Reports Server (NTRS)

Joshi, Suresh M.; Kelkar, Atul G.; Maghami, Peiman G.

1995-01-01

The problem of controlling a class of nonlinear multibody flexible space systems consisting of a flexible central body to which a number of articulated appendages are attached is considered. Collocated actuators and sensors are assumed, and global asymptotic stability of such systems is established under a nonlinear dissipative control law. The stability is shown to be robust to unmodeled dynamics and parametric uncertainties. For a special case in which the attitude motion of the central body is small, the system, although still nonlinear, is shown to be stabilized by linear dissipative control laws. Two types of linear controllers are considered: static dissipative (constant gain) and dynamic dissipative. The static dissipative control law is also shown to provide robust stability in the presence of certain classes of actuator and sensor nonlinearities and actuator dynamics. The results obtained for this special case can also be readily applied for controlling single-body linear flexible space structures. For this case, a synthesis technique for the design of a suboptimal dynamic dissipative controller is also presented. The results obtained in this paper are applicable to a broad class of multibody and single-body systems such as flexible multilink manipulators, multipayload space platforms, and space antennas. The stability proofs use the Lyapunov approach and exploit the inherent passivity of such systems.

Dynamic output feedback control of a flexible air-breathing hypersonic vehicle via T-S fuzzy approach

NASA Astrophysics Data System (ADS)

Hu, Xiaoxiang; Wu, Ligang; Hu, Changhua; Wang, Zhaoqiang; Gao, Huijun

2014-08-01

By utilising Takagi-Sugeno (T-S) fuzzy set approach, this paper addresses the robust H∞ dynamic output feedback control for the non-linear longitudinal model of flexible air-breathing hypersonic vehicles (FAHVs). The flight control of FAHVs is highly challenging due to the unique dynamic characteristics, and the intricate couplings between the engine and fight dynamics and external disturbance. Because of the dynamics' enormous complexity, currently, only the longitudinal dynamics models of FAHVs have been used for controller design. In this work, T-S fuzzy modelling technique is utilised to approach the non-linear dynamics of FAHVs, then a fuzzy model is developed for the output tracking problem of FAHVs. The fuzzy model contains parameter uncertainties and disturbance, which can approach the non-linear dynamics of FAHVs more exactly. The flexible models of FAHVs are difficult to measure because of the complex dynamics and the strong couplings, thus a full-order dynamic output feedback controller is designed for the fuzzy model. A robust H∞ controller is designed for the obtained closed-loop system. By utilising the Lyapunov functional approach, sufficient solvability conditions for such controllers are established in terms of linear matrix inequalities. Finally, the effectiveness of the proposed T-S fuzzy dynamic output feedback control method is demonstrated by numerical simulations.

An intervention program to promote health-related physical fitness in nurses.

PubMed

Yuan, Su-Chuan; Chou, Ming-Chih; Hwu, Lien-Jen; Chang, Yin-O; Hsu, Wen-Hsin; Kuo, Hsien-Wen

2009-05-01

To assess the effects of exercise intervention on nurses' health-related physical fitness. Regular exercise that includes gymnastics or aerobics has a positive effect on fitness. In Taiwan, there are not much data which assess the effects of exercise intervention on nurses' health-related physical fitness. Many studies have reported the high incidence of musculoskeletal disorders (MSDs) in nurses However, there has been limited research on intervention programs that are designed to improve the general physical fitness of nurses. A quasi-experimental study was conducted at a medical centre in central Taiwan. Ninety nurses from five different units of a hospital volunteered to participate in this study and participated in an experimental group and a control group. The experimental group engaged in a three-month intervention program consisting of treadmill exercise. Indicators of the health-related physical fitness of both groups were established and assessed before and after the intervention. Before intervention, the control group had significantly better grasp strength, flexibility and durability of abdominal muscles than the experimental group (p < 0.05). After the intervention, logistic regression was used to adjust for marital status, work duration, regular exercise and workload and found that the experimental group performed significantly better (p < 0.05) on body mass index, grasp strength, flexibility, durability of abdominal and back muscles and cardiopulmonary function. This study demonstrates that the development and implementation of an intervention program can promote and improve the health-related physical fitness of nurses. It is suggested that nurses engage in an exercise program while in the workplace to lower the risk of MSDs and to promote working efficiency.

Modeling, design, and control of flexible manipulator arms: Status and trends

NASA Technical Reports Server (NTRS)

Book, Wayne J.

1989-01-01

The desire for higher performance manipulators has lead to dynamic behavior in which the flexibility is an essential aspect. The mathematical representations commonly used in modeling flexible arms and arms with flexible drives are examined first. Then design considerations directly arising from the flexible nature of the arm are discussed. Finally, controls of joints for general and tip motion are discussed.

Dynamics modeling and adaptive control of flexible manipulators

NASA Technical Reports Server (NTRS)

Sasiadek, J. Z.

1991-01-01

An application of Model Reference Adaptive Control (MRAC) to the position and force control of flexible manipulators and robots is presented. A single-link flexible manipulator is analyzed. The problem was to develop a mathematical model of a flexible robot that is accurate. The objective is to show that the adaptive control works better than 'conventional' systems and is suitable for flexible structure control.

Dynamic analysis of horizontal axis wind turbine by thin-walled beam theory

NASA Astrophysics Data System (ADS)

Wang, Jianhong; Qin, Datong; Lim, Teik C.

2010-08-01

A mixed flexible-rigid multi-body mathematical model is applied to predict the dynamic performance of a wind turbine system. Since the tower and rotor are both flexible thin-walled structures, a consistent expression for their deformations is applied, which employs a successive series of transformations to locate any point on the blade and tower relative to an inertial coordinate system. The kinetic and potential energy terms of each flexible body and rigid body are derived for use in the Lagrange approach to formulate the wind turbine system's governing equation. The mode shapes are then obtained from the free vibration solution, while the distributions of dynamic stress and displacement of the tower and rotor are computed from the forced vibration response analysis. Using this dynamic model, the influence of the tower's stiffness on the blade tip deformation is studied. From the analysis, it is evident that the proposed model not only inherits the simplicity of the traditional 1-D beam element, but also able to provide detailed information about the tower and rotor response due to the incorporation of the flexible thin-walled beam theory.

Large deflections and vibrations of a tip pulled beam with variable transversal section

NASA Astrophysics Data System (ADS)

Kurka, P.; Izuka, J.; Gonzalez, P.; Teixeira, L. H.

2016-10-01

The use of long flexible probes in outdoors exploration vehicles, as opposed to short and rigid arms, is a convenient way to grant easier access to regions of scientific interest such as terrain slopes and cliff sides. Longer and taller arms can also provide information from a wider exploration horizon. The drawback of employing long and flexible exploration probes is the fact that its vibration is not easily controlled in real time operation by means of a simple analytic linear dynamic model. The numerical model required to describe the dynamics of a very long and flexible structure is often very large and of slow computational convergence. The present work proposes a simplified numerical model of a long flexible beam with variable cross section, which is statically deflected by a pulling cable. The paper compares the proposed simplified model with experimental data regarding the static and dynamic characteristics of a beam with variable cross section. The simulations show the effectiveness of the simplified dynamic model employed in an active control loop to suppress tip vibrations of the beam.

Health Benefits of Zumba Fitness Training: A Systematic Review.

PubMed

Vendramin, Barbara; Bergamin, Marco; Gobbo, Stefano; Cugusi, Lucia; Duregon, Federica; Bullo, Valentina; Zaccaria, Marco; Neunhaeuserer, Daniel; Ermolao, Andrea

2016-12-01

As an alternative to the traditional approach to physical exercise, new kinds of organized physical activity have been developed designed to engage large segments of the population. Among these, Zumba fitness is extremely popular, with a growing number of participants. This article aims to summarize and analyze the body of evidence on the effects of Zumba fitness interventions on physical function, fitness, and wellbeing. TYPE: Systematic review. Keyword "Zumba" was identified as term for the literature research in MEDLINE, Scopus, Bandolier, PEDro, and Web of Science. Only studies published in peer-reviewed journals written in English language were considered. Eleven manuscripts were classified as eligible with 586 total participants, ranging in age from 18 to 65 years. After a quality appraisal, we classified 4 studies as high-quality investigations and 7 as low quality. Results were summarized in several domains: "anthropometric parameters and body composition," "hormonal and metabolic profiles," "aerobic and cardiovascular performance," "muscular fitness parameters," and "quality of life, pain score and physical activity questionnaire." Results from this systematic review indicated that Zumba fitness could be considered an effective type of physical activity able to improve aerobic capacity. Small but positive benefits were noted for reducing body weight and other body measurements. Furthermore, other effects, including psychological and social benefits on quality of life, were found after Zumba fitness interventions. Otherwise, limited evidence described positive effects on muscular strength and flexibility. Zumba fitness could be considered an effective type of physical activity able to improve aerobic capacity. Limited evidence described positive effects on muscular strength and flexibility. II. Copyright © 2016 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

The left hand second to fourth digit ratio (2D:4D) is not related to any physical fitness component in adolescent girls.

PubMed

Peeters, Maarten W; Van Aken, Katrijn; Claessens, Albrecht L

2013-01-01

The second to fourth-digit-ratio (2D:4D), a putative marker of prenatal androgen action and a sexually dimorphic trait, has been suggested to be related with fitness and sports performance, although results are not univocal. Most studies however focus on a single aspect of physical fitness or one sports discipline. In this study the 2D:4D ratio of 178 adolescent girls (age 13.5-18 y) was measured on X-rays of the left hand. The relation between 2D:4D digit ratio and multiple aspects of physical fitness (balance, speed of limb movement, flexibility, explosive strength, static strength, trunk strength, functional strength, running speed/agility, and endurance) was studied by correlation analyses and stepwise multiple regression. For comparison the relation between these physical fitness components and a selected number of objectively measured anthropometric traits (stature, mass, BMI, somatotype components and the Bayer & Bailey androgyny index) are presented alongside the results of 2D:4D digit ratio. Left hand 2D:4D digit ratio (0.925±0.019) was not significantly correlated with any of the physical fitness components nor any of the anthropometric variables included in the present study. 2D:4D did not enter the multiple stepwise regression for any of the physical fitness components in which other anthropometric traits explained between 9.2% (flexibility) and 33.9% (static strength) of variance. Unlike other anthropometric traits the 2D:4D digit ratio does not seem to be related to any physical fitness component in adolescent girls and therefore most likely should not be considered in talent detection programs for sporting ability in girls.

Stability Result For Dynamic Inversion Devised to Control Large Flexible Aircraft

NASA Technical Reports Server (NTRS)

Gregory, Irene M.

2001-01-01

High performance aircraft of the future will be designed lighter, more maneuverable, and operate over an ever expanding flight envelope. One of the largest differences from the flight control perspective between current and future advanced aircraft is elasticity. Over the last decade, dynamic inversion methodology has gained considerable popularity in application to highly maneuverable fighter aircraft, which were treated as rigid vehicles. This paper is an initial attempt to establish global stability results for dynamic inversion methodology as applied to a large, flexible aircraft. This work builds on a previous result for rigid fighter aircraft and adds a new level of complexity that is the flexible aircraft dynamics, which cannot be ignored even in the most basic flight control. The results arise from observations of the control laws designed for a new generation of the High-Speed Civil Transport aircraft.

The Modelling of Axially Translating Flexible Beams

NASA Astrophysics Data System (ADS)

Theodore, R. J.; Arakeri, J. H.; Ghosal, A.

1996-04-01

The axially translating flexible beam with a prismatic joint can be modelled by using the Euler-Bernoulli beam equation together with the convective terms. In general, the method of separation of variables cannot be applied to solve this partial differential equation. In this paper, a non-dimensional form of the Euler Bernoulli beam equation is presented, obtained by using the concept of group velocity, and also the conditions under which separation of variables and assumed modes method can be used. The use of clamped-mass boundary conditions leads to a time-dependent frequency equation for the translating flexible beam. A novel method is presented for solving this time dependent frequency equation by using a differential form of the frequency equation. The assume mode/Lagrangian formulation of dynamics is employed to derive closed form equations of motion. It is shown by using Lyapunov's first method that the dynamic responses of flexural modal variables become unstable during retraction of the flexible beam, which the dynamic response during extension of the beam is stable. Numerical simulation results are presented for the uniform axial motion induced transverse vibration for a typical flexible beam.

3D structural fluctuation of IgG1 antibody revealed by individual particle electron tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Xing; Zhang, Lei; Tong, Huimin

2015-05-05

Commonly used methods for determining protein structure, including X-ray crystallography and single-particle reconstruction, often provide a single and unique three-dimensional (3D) structure. However, in these methods, the protein dynamics and flexibility/fluctuation remain mostly unknown. Here, we utilized advances in electron tomography (ET) to study the antibody flexibility and fluctuation through structural determination of individual antibody particles rather than averaging multiple antibody particles together. Through individual-particle electron tomography (IPET) 3D reconstruction from negatively-stained ET images, we obtained 120 ab-initio 3D density maps at an intermediate resolution (~1–3 nm) from 120 individual IgG1 antibody particles. Using these maps as a constraint, wemore » derived 120 conformations of the antibody via structural flexible docking of the crystal structure to these maps by targeted molecular dynamics simulations. Statistical analysis of the various conformations disclosed the antibody 3D conformational flexibility through the distribution of its domain distances and orientations. This blueprint approach, if extended to other flexible proteins, may serve as a useful methodology towards understanding protein dynamics and functions.« less

Metal Building Systems Fit To Be Tried

ERIC Educational Resources Information Center

Nation's Schools, 1974

1974-01-01

Describes the advantages of metal building systems in school construction. These advantages include faster occupancy, lower initial costs, reduced maintenance, flexibility, and predictability of cost. (Author/DN)

Physical fitness, injuries, and team performance in soccer.

PubMed

Arnason, Arni; Sigurdsson, Stefan B; Gudmundsson, Arni; Holme, Ingar; Engebretsen, Lars; Bahr, Roald

2004-02-01

To investigate the relationship between physical fitness and team success in soccer, and to test for differences in physical fitness between different player positions. Participants were 306 male soccer players from 17 teams in the two highest divisions in Iceland. Just before the start of the 1999 soccer season, the following variables were tested: height and weight, body composition, flexibility, leg extension power, jump height, and peak O2 uptake. Injuries and player participation in matches and training were recorded through the 4-month competitive season. Team average physical fitness was compared with team success (final league standing) using a linear regression model. Physical fitness was also compared between players in different playing positions. A significant relationship was found between team average jump height (countermovement jump and standing jump) and team success (P = 0.009 and P = 0.012, respectively). The same trend was also found for leg extension power (P = 0.097), body composition (% body fat, P = 0.07), and the total number of injury days per team (P = 0.09). Goalkeepers demonstrated different fitness characteristics from outfield players. They were taller and heavier, more flexible in hip extension and knee flexion, and had higher leg extension power and a lower peak O2 uptake. However, only minor differences were observed between defenders, midfield players, and attackers. Coaches and medical support teams should pay more attention to jump and power training, as well as preventive measures and adequate rehabilitation of previous injuries to increase team success.

Reference standards to assess physical fitness of children and adolescents of Brazil: an approach to the students of the Lake Itaipú region—Brazil

PubMed Central

Hobold, Edilson; Pires-Lopes, Vitor; Gómez-Campos, Rossana; de Arruda, Miguel; Andruske, Cynthia Lee; Pacheco-Carrillo, Jaime

2017-01-01

Background The importance of assessing body fat variables and physical fitness tests plays an important role in monitoring the level of activity and physical fitness of the general population. The objective of this study was to develop reference norms to evaluate the physical fitness aptitudes of children and adolescents based on age and sex from the lake region of Itaipú, Brazil. Methods A descriptive cross-sectional study was carried out with 5,962 students (2,938 males and 3,024 females) with an age range of 6.0 and 17.9 years. Weight (kg), height (cm), and triceps (mm), and sub-scapular skinfolds (mm) were measured. Body Mass Index (BMI kg/m2) was calculated. To evaluate the four physical fitness aptitude dimensions (morphological, muscular strength, flexibility, and cardio-respiratory), the following physical education tests were given to the students: sit-and-reach (cm), push-ups (rep), standing long jump (cm), and 20-m shuttle run (m). Results and Discussion Females showed greater flexibility in the sit-and-reach test and greater body fat than the males. No differences were found in BMI. Percentiles were created for the four components for the physical fitness aptitudes, BMI, and skinfolds by using the LMS method based on age and sex. The proposed reference values may be used for detecting talents and promoting health in children and adolescents. PMID:29204319

Motor competence and health related physical fitness in youth: A systematic review.

PubMed

Cattuzzo, Maria Teresa; Dos Santos Henrique, Rafael; Ré, Alessandro Hervaldo Nicolai; de Oliveira, Ilana Santos; Melo, Bruno Machado; de Sousa Moura, Mariana; de Araújo, Rodrigo Cappato; Stodden, David

2016-02-01

This study aimed to review the scientific evidence on associations between motor competence (MC) and components of health related physical fitness (HRPF), in children and adolescents. Systematic review. Systematic search of Academic Search Premier, ERIC, PubMed, PsycInfo, Scopus, SportDiscus, and Web of Science databases was undertaken between October 2012 and December 2013. Studies examining associations between MC and HRPF components (body weight status, cardiorespiratory fitness, musculoskeletal fitness and flexibility) in healthy children and adolescents, published between 1990 and 2013, were included. Risk of bias within studies was assessed using CONSORT and STROBE guidelines. The origin, design, sample, measure of MC, measure of the HRPF, main results and statistics of the studies were analyzed and a narrative synthesis was conducted. Forty-four studies matched all criteria; 16 were classified as low risk of bias and 28 as medium risk. There is strong scientific evidence supporting an inverse association between MC and body weight status (27 out of 33 studies) and a positive association between MC and cardiorespiratory fitness (12 out of 12 studies) and musculoskeletal fitness (7 out of 11 studies). The relationship between MC and flexibility was uncertain. Considering the noted associations between various assessments of MC and with multiple aspects of HRPF, the development of MC in childhood may both directly and indirectly augment HRPF and may serve to enhance the development of long-term health outcomes in children and adolescents. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Controlling Flexible Manipulators, an Experimental Investigation. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Hastings, Gordon Greene

1986-01-01

Lightweight, slender manipulators offer faster response and/or greater workspace range for the same size actuators than tradional manipulators. Lightweight construction of manipulator links results in increased structural flexibility. The increase flexibility must be considered in the design of control systems to properly account for the dynamic flexible vibrations and static deflections. Real time control of the flexible manipulator vibrations are experimentally investigated. Models intended for real-time control of distributed parameter system such as flexible manipulators rely on model approximation schemes. An linear model based on the application of Lagrangian dynamics to a rigid body mode and a series of separable flexible modes is examined with respect to model order requirements, and modal candidate selection. Balanced realizations are applied to the linear flexible model to obtain an estimate of appropriate order for a selected model. Describing the flexible deflections as a linear combination of modes results in measurements of beam state, which yield information about several modes. To realize the potential of linear systems theory, knowledge of each state must be available. State estimation is also accomplished by implementation of a Kalman Filter. State feedback control laws are implemented based upon linear quadratic regulator design.

Exploration of Multi-State Conformational Dynamics and Underlying Global Functional Landscape of Maltose Binding Protein

PubMed Central

Wang, Yong; Tang, Chun; Wang, Erkang; Wang, Jin

2012-01-01

An increasing number of biological machines have been revealed to have more than two macroscopic states. Quantifying the underlying multiple-basin functional landscape is essential for understanding their functions. However, the present models seem to be insufficient to describe such multiple-state systems. To meet this challenge, we have developed a coarse grained triple-basin structure-based model with implicit ligand. Based on our model, the constructed functional landscape is sufficiently sampled by the brute-force molecular dynamics simulation. We explored maltose-binding protein (MBP) which undergoes large-scale domain motion between open, apo-closed (partially closed) and holo-closed (fully closed) states responding to ligand binding. We revealed an underlying mechanism whereby major induced fit and minor population shift pathways co-exist by quantitative flux analysis. We found that the hinge regions play an important role in the functional dynamics as well as that increases in its flexibility promote population shifts. This finding provides a theoretical explanation of the mechanistic discrepancies in PBP protein family. We also found a functional “backtracking” behavior that favors conformational change. We further explored the underlying folding landscape in response to ligand binding. Consistent with earlier experimental findings, the presence of ligand increases the cooperativity and stability of MBP. This work provides the first study to explore the folding dynamics and functional dynamics under the same theoretical framework using our triple-basin functional model. PMID:22532792

Analysis of electric vehicle extended range misalignment based on rigid-flexible dynamics

NASA Astrophysics Data System (ADS)

Xu, Xiaowei; Lv, Mingliang; Chen, Zibo; Ji, Wei; Gao, Ruiceng

2017-04-01

The safety of the extended range electric vehicle is seriously affected by the misalignment fault. Therefore, this paper analyzed the electric vehicle extended range misalignment based on rigid-flexible dynamics. Through comprehensively applied the hybrid modeling of rigid-flexible and the method of fault diagnosis of machinery and equipment comprehensively, it established a extender hybrid rigid flexible mechanical model by means of the software ADAMS and ANSYS. By setting the relevant parameters to simulate the misalignment of shafting, the failure phenomenon, the spectrum analysis and the evolution rules were analyzed. It concluded that 0.5th and 1 harmonics are considered as the characteristic parameters of misalignment diagnostics for electric vehicle extended range.

The acute effects of stretching with vibration on dynamic flexibility in young female gymnasts.

PubMed

Johnson, Aaron W; Warcup, Caisa N; Seeley, Matthew K; Eggett, Dennis; Feland, Jeffery B

2018-01-10

While stretching with vibration has been shown to improve static flexibility; the effect of stretching with vibration on dynamic flexibility is not well known. The purpose of this study was to examine the effectiveness of stretching with vibration on acute dynamic flexibility and jump height in novice and advanced competitive female gymnasts during a split jump. Female gymnast (n=27, age: 11.5 ± 1.7 years, Junior Olympic levels 5-10) participated in this cross-over study. Dynamic flexibility during gymnastic split jumps were video recorded and analyzed with Dartfish software. All participants completed both randomized stretching protocols with either the vibration platform turned on (VIB) (frequency of 30 Hz and 2 mm amplitude) or off (NoVIB) separated by 48 h. Participants performed 4 sets of three stretches on the vibration platform. Each stretch was held for 30 s with 5 s rest for a total of 7 min of stretch. Split jump flexibility decreased significantly from pre to post measurement in both VIB (-5.8°±5.9°) (p<0.001) and NoVIB (-2.6°±6.1°) (p=0.041) conditions (adjusted for gymnast level). This effect was greatest in lower skill level gymnasts (p=0.003), while the highest skill level gymnasts showed no significant decrease in the split jump (p=0.105). Jump height was not significantly different between conditions (p=0.892) or within groups (p=0.880). An acute session of static stretching with or without vibration immediately before performance does not alter jump height. Stretching with vibration immediately prior to gymnastics competition decreases split jump flexibility in lower level gymnasts more than upper level gymnasts.

Control and trajectory design of a highly flexible air vehicle with a distributed sensing architecture

NASA Astrophysics Data System (ADS)

Pachikara, Abraham James

Next generational aircraft are becoming very flexible due to efforts to reduce weight and increase aerodynamic efficiency. As a result, flight control systems and trajectories that were designed with traditional rigid body assumptions may no longer become valid. When an aircraft becomes more flexible, the shape of the aircraft can deform significantly due to the aeroservoelastic dynamics. No longer are few sensors located at the CG and elsewhere will be enough to maximize performance. Instead, a full suite of sensors will be needed all throughout the aircraft to accurately measure the complete aerodynamic distribution and dynamics. First, a parametric study will be conducted to understand how flexibility impacts both the open-loop and closed-loop dynamics of a generic micro air vehicle (MAV). Once the impact of flexibility on the MAV's aeroservoelastic dynamics is well understood, an aeroservoelastic flight controller will be designed that leverages a "Fly-By-Feel" sensor architecture. A sensor architecture will be developed that uses several sensors to estimate the MAV's full aerodynamic and inertial distribution along with inertial sensors at the CG. A modal filtering approach will be used for the relevant sensor management and to extract useful modal characteristics from the sensor data. Once that is done, a controller will be designed for maneuver tracking. Once a flight controller has been designed, a set of representative motion primitives for the MAV can be developed that model how the aircraft moves for trajectory generation. Then trajectories can be developed for the flexible vehicle. Analysis will then be conducted to understand how flexibility impacts the creation of trajectories and MAV performance metrics.

Model systems for single molecule polymer dynamics

PubMed Central

Latinwo, Folarin

2012-01-01

Double stranded DNA (dsDNA) has long served as a model system for single molecule polymer dynamics. However, dsDNA is a semiflexible polymer, and the structural rigidity of the DNA double helix gives rise to local molecular properties and chain dynamics that differ from flexible chains, including synthetic organic polymers. Recently, we developed single stranded DNA (ssDNA) as a new model system for single molecule studies of flexible polymer chains. In this work, we discuss model polymer systems in the context of “ideal” and “real” chain behavior considering thermal blobs, tension blobs, hydrodynamic drag and force–extension relations. In addition, we present monomer aspect ratio as a key parameter describing chain conformation and dynamics, and we derive dynamical scaling relations in terms of this molecular-level parameter. We show that asymmetric Kuhn segments can suppress monomer–monomer interactions, thereby altering global chain dynamics. Finally, we discuss ssDNA in the context of a new model system for single molecule polymer dynamics. Overall, we anticipate that future single polymer studies of flexible chains will reveal new insight into the dynamic behavior of “real” polymers, which will highlight the importance of molecular individualism and the prevalence of non-linear phenomena. PMID:22956980

A user's guide to the Flexible Spacecraft Dynamics and Control Program

NASA Technical Reports Server (NTRS)

Fedor, J. V.

1984-01-01

A guide to the use of the Flexible Spacecraft Dynamics Program (FSD) is presented covering input requirements, control words, orbit generation, spacecraft description and simulation options, and output definition. The program can be used in dynamics and control analysis as well as in orbit support of deployment and control of spacecraft. The program is applicable to inertially oriented spinning, Earth oriented or gravity gradient stabilized spacecraft. Internal and external environmental effects can be simulated.

A general framework to test gravity using galaxy clusters - I. Modelling the dynamical mass of haloes in f(R) gravity

NASA Astrophysics Data System (ADS)

Mitchell, Myles A.; He, Jian-hua; Arnold, Christian; Li, Baojiu

2018-06-01

We propose a new framework for testing gravity using cluster observations, which aims to provide an unbiased constraint on modified gravity models from Sunyaev-Zel'dovich (SZ) and X-ray cluster counts and the cluster gas fraction, among other possible observables. Focusing on a popular f(R) model of gravity, we propose a novel procedure to recalibrate mass scaling relations from Λ cold dark matter (ΛCDM) to f(R) gravity for SZ and X-ray cluster observables. We find that the complicated modified gravity effects can be simply modelled as a dependence on a combination of the background scalar field and redshift, fR(z)/(1 + z), regardless of the f(R) model parameter. By employing a large suite of N-body simulations, we demonstrate that a theoretically derived tanh fitting formula is in excellent agreement with the dynamical mass enhancement of dark matter haloes for a large range of background field parameters and redshifts. Our framework is sufficiently flexible to allow for tests of other models and inclusion of further observables, and the one-parameter description of the dynamical mass enhancement can have important implications on the theoretical modelling of observables and on practical tests of gravity.

Fitting direct covariance structures by the MSTRUCT modeling language of the CALIS procedure.

PubMed

Yung, Yiu-Fai; Browne, Michael W; Zhang, Wei

2015-02-01

This paper demonstrates the usefulness and flexibility of the general structural equation modelling (SEM) approach to fitting direct covariance patterns or structures (as opposed to fitting implied covariance structures from functional relationships among variables). In particular, the MSTRUCT modelling language (or syntax) of the CALIS procedure (SAS/STAT version 9.22 or later: SAS Institute, 2010) is used to illustrate the SEM approach. The MSTRUCT modelling language supports a direct covariance pattern specification of each covariance element. It also supports the input of additional independent and dependent parameters. Model tests, fit statistics, estimates, and their standard errors are then produced under the general SEM framework. By using numerical and computational examples, the following tests of basic covariance patterns are illustrated: sphericity, compound symmetry, and multiple-group covariance patterns. Specification and testing of two complex correlation structures, the circumplex pattern and the composite direct product models with or without composite errors and scales, are also illustrated by the MSTRUCT syntax. It is concluded that the SEM approach offers a general and flexible modelling of direct covariance and correlation patterns. In conjunction with the use of SAS macros, the MSTRUCT syntax provides an easy-to-use interface for specifying and fitting complex covariance and correlation structures, even when the number of variables or parameters becomes large. © 2014 The British Psychological Society.

Quick-connect fasteners for assembling devices in space

NASA Technical Reports Server (NTRS)

Wesselski, Clarence J. (Inventor); Evenson, Erik E. (Inventor); Ruiz, Steve L. (Inventor)

1992-01-01

A quick-connect fastener of a relatively-simple straightforward design is arranged with a tubular body adapted to be engaged against an attachment fitting in coincidental alignment with an opening in that fitting. A tubular collet having flexible finger projecting from its forward end is arranged in the fastener body to be shifted forwardly by an elongated expander member coaxially arranged within the tubular collet for advancing the collet fingers into the opening in the attachment fitting. Biasing means are arranged between the elongated expander member and a rotatable actuator which is threadedly mounted within the tubular collet so as to be rotated for urging the expander member into engagement with the collet fingers. A first coupling member is arranged on the rotatable actuator to be accessible from outside of the fastener so that a second coupling member on the distal end of a flexible shaft can be introduced into the fastener body and coupled to the first coupling member to enable a typical actuating tool coupled to the shaft outside of the fastener body to be operated for advancing the outwardly-enlarged ends of the collet fingers into the opening in the attachment fitting and thereafter rotating the actuator member to expand the fingers to that attachment fitting. Upon expansion of the collet fingers, the biasing means impose a biasing force on the expander to releasably retain the fingers in their latching positions.

The effect of inertial coupling in the dynamics and control of flexible robotic manipulators

NASA Technical Reports Server (NTRS)

Tesar, Delbert; Curran, Carol Cockrell; Graves, Philip Lee

1988-01-01

A general model of the dynamics of flexible robotic manipulators is presented, including the gross motion of the links, the vibrations of the links and joints, and the dynamic coupling between the gross motions and vibrations. The vibrations in the links may be modeled using lumped parameters, truncated modal summation, a component mode synthesis method, or a mixture of these methods. The local link inertia matrix is derived to obtain the coupling terms between the gross motion of the link and the vibrations of the link. Coupling between the motions of the links results from the kinematic model, which utilizes the method of kinematic influence. The model is used to simulate the dynamics of a flexible space-based robotic manipulator which is attached to a spacecraft, and is free to move with respect to the inertial reference frame. This model may be used to study the dynamic response of the manipulator to the motions of its joints, or to externally applied disturbances.

Flexible Modes Control Using Sliding Mode Observers: Application to Ares I

NASA Technical Reports Server (NTRS)

Shtessel, Yuri B.; Hall, Charles E.; Baev, Simon; Orr, Jeb S.

2010-01-01

The launch vehicle dynamics affected by bending and sloshing modes are considered. Attitude measurement data that are corrupted by flexible modes could yield instability of the vehicle dynamics. Flexible body and sloshing modes are reconstructed by sliding mode observers. The resultant estimates are used to remove the undesirable dynamics from the measurements, and the direct effects of sloshing and bending modes on the launch vehicle are compensated by means of a controller that is designed without taking the bending and sloshing modes into account. A linearized mathematical model of Ares I launch vehicle was derived based on FRACTAL, a linear model developed by NASA/MSFC. The compensated vehicle dynamics with a simple PID controller were studied for the launch vehicle model that included two bending modes, two slosh modes and actuator dynamics. A simulation study demonstrated stable and accurate performance of the flight control system with the augmented simple PID controller without the use of traditional linear bending filters.

Drive-train dynamics technology - State-of-the-art and design of a test facility for advanced development

NASA Technical Reports Server (NTRS)

Badgley, R. H.; Fleming, D. P.; Smalley, A. J.

1975-01-01

A program for the development and verification of drive-train dynamic technology is described along with its basis and the results expected from it. A central feature of this program is a drive-train test facility designed for the testing and development of advanced drive-train components, including shaft systems, dampers, and couplings. Previous efforts in designing flexible dynamic drive-train systems are reviewed, and the present state of the art is briefly summarized. The design of the test facility is discussed with major attention given to the formulation of the test-rig concept, dynamic scaling of model shafts, and the specification of design parameters. Specific efforts envisioned for the test facility are briefly noted, including evaluations of supercritical test shafts, stability thresholds for various sources and types of instabilities that can exist in shaft systems, effects of structural flexibility on the dynamic performance of dampers, and methods for vibration control in two-level and three-level flexible shaft systems.

Constructions of Dynamic Geometry: A Study of the Interpretative Flexibility of Educational Software in Classroom Practice

ERIC Educational Resources Information Center

Ruthven, Kenneth; Hennessy, Sara; Deaney, Rosemary

2008-01-01

The idea of "interpretative flexibility" underpins new approaches to studying technological artefacts and curricular resources in use. This paper opens by reviewing, in this light, the evolving design of dynamic geometry, its pioneering use within classroom projects, and early sketches of its mainstream use in ordinary classrooms. After…

Flexible weapons architecture design

NASA Astrophysics Data System (ADS)

Pyant, William C., III

Present day air-delivered weapons are of a closed architecture, with little to no ability to tailor the weapon for the individual engagement. The closed architectures require weaponeers to make the target fit the weapon instead of fitting the individual weapons to a target. The concept of a flexible weapons aims to modularize weapons design using an open architecture shell into which different modules are inserted to achieve the desired target fractional damage while reducing cost and civilian casualties. This thesis shows that the architecture design factors of damage mechanism, fusing, weapons weight, guidance, and propulsion are significant in enhancing weapon performance objectives, and would benefit from modularization. Additionally, this thesis constructs an algorithm that can be used to design a weapon set for a particular target class based on these modular components.

NASA Workshop on Distributed Parameter Modeling and Control of Flexible Aerospace Systems

NASA Technical Reports Server (NTRS)

Marks, Virginia B. (Compiler); Keckler, Claude R. (Compiler)

1994-01-01

Although significant advances have been made in modeling and controlling flexible systems, there remains a need for improvements in model accuracy and in control performance. The finite element models of flexible systems are unduly complex and are almost intractable to optimum parameter estimation for refinement using experimental data. Distributed parameter or continuum modeling offers some advantages and some challenges in both modeling and control. Continuum models often result in a significantly reduced number of model parameters, thereby enabling optimum parameter estimation. The dynamic equations of motion of continuum models provide the advantage of allowing the embedding of the control system dynamics, thus forming a complete set of system dynamics. There is also increased insight provided by the continuum model approach.

The effect of support flexibility and damping on the dynamic response of a single mass flexible rotor in elastic bearings

NASA Technical Reports Server (NTRS)

Kirk, R. G.; Gunter, E. J.

1972-01-01

The dynamic unabalance response and transient motion of the single mass Jeffcott rotor in elastic bearings mounted on damped, flexible supports are discussed. A steady state analysis of the shaft and the bearing housing motion was made by assuming synchronous precession of the system. The conditions under which the support system would act as a dynamic vibration absorber at the rotor critical speed were studied. Plots of the rotor and support amplitudes, phase angles, and forces transmitted were evaluated by the computer and the performance curves were plotted by an automatic plotter unit. Curves are presented on the optimization of the support housing characteristics of attenuate the rotor synchronous unbalance response.

Aircraft Crash Survival Design Guide. Volume 5. Aircraft Postcrash Survival

DTIC Science & Technology

1980-01-01

The use of flexible hose armored with a steel- braided harness is strongly suggested in areas of anticipated dragging or structural impingement. In... Hose end coupling Metal tank fitting Breakaway valve Frangible section i ITEM LOWEST FAILURE LOAD (LB)* FAILURE MODE Flex hose 3000 Tensile breakage...61 21 Typical breakaway load calculation for in-line breakaway valve. . . . . . . . . 62 22 Standard hose fitting dimensions

A study of pressure losses in residential air distribution systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abushakra, Bass; Walker, Iain S.; Sherman, Max H.

2002-07-01

An experimental study was conducted to evaluate the pressure drop characteristics of residential duct system components that are either not available or not thoroughly (sometimes incorrectly) described in existing duct design literature. The tests were designed to imitate cases normally found in typical residential and light commercial installations. The study included three different sizes of flexible ducts, under different compression configurations, splitter boxes, supply boots, and a fresh air intake hood. The experimental tests conformed to ASHRAE Standard 120P--''Methods of Testing to Determine Flow Resistance of HVAC Air Ducts and Fittings''. The flexible duct study covered compressibility and bending effectsmore » on the total pressure drop, and the results showed that the available published references tend to underestimate the effects of compression in flexible ducts that can increase pressure drops by up to a factor of nine. The supply boots were tested under different configurations including a setup where a flexible duct elbow connection was considered as an integral part of the supply boot. The supply boots results showed that diffusers can increase the pressure drop by up to a factor of two in exit fittings, and the installation configuration can increase the pressure drop by up to a factor of five. The results showed that it is crucial for designers and contractors to be aware of the compressibility effects of the flexible duct, and the installation of supply boots and diffusers.« less

On the apparent insignificance of the randomness of flexible joints on large space truss dynamics

NASA Technical Reports Server (NTRS)

Koch, R. M.; Klosner, J. M.

1993-01-01

Deployable periodic large space structures have been shown to exhibit high dynamic sensitivity to period-breaking imperfections and uncertainties. These can be brought on by manufacturing or assembly errors, structural imperfections, as well as nonlinear and/or nonconservative joint behavior. In addition, the necessity of precise pointing and position capability can require the consideration of these usually negligible and unknown parametric uncertainties and their effect on the overall dynamic response of large space structures. This work describes the use of a new design approach for the global dynamic solution of beam-like periodic space structures possessing parametric uncertainties. Specifically, the effect of random flexible joints on the free vibrations of simply-supported periodic large space trusses is considered. The formulation is a hybrid approach in terms of an extended Timoshenko beam continuum model, Monte Carlo simulation scheme, and first-order perturbation methods. The mean and mean-square response statistics for a variety of free random vibration problems are derived for various input random joint stiffness probability distributions. The results of this effort show that, although joint flexibility has a substantial effect on the modal dynamic response of periodic large space trusses, the effect of any reasonable uncertainty or randomness associated with these joint flexibilities is insignificant.

Expansion of epicyclic gear dynamic analysis program

NASA Technical Reports Server (NTRS)

Boyd, Linda Smith; Pike, James A.

1987-01-01

The multiple mesh/single stage dynamics program is a gear tooth analysis program which determines detailed geometry, dynamic loads, stresses, and surface damage factors. The program can analyze a variety of both epicyclic and single mesh systems with spur or helical gear teeth including internal, external, and buttress tooth forms. The modifications refine the options for the flexible carrier and flexible ring gear rim and adds three options: a floating Sun gear option; a natural frequency option; and a finite element compliance formulation for helical gear teeth. The option for a floating Sun incorporates two additional degrees of freedom at the Sun center. The natural frequency option evaluates the frequencies of planetary, star, or differential systems as well as the effect of additional springs at the Sun center and those due to a flexible carrier and/or ring gear rim. The helical tooth pair finite element calculated compliance is obtained from an automated element breakup of the helical teeth and then is used with the basic gear dynamic solution and stress postprocessing routines. The flexible carrier or ring gear rim option for planetary and star spur gear systems allows the output torque per carrier and ring gear rim segment to vary based on the dynamic response of the entire system, while the total output torque remains constant.

Effects of aquatic exercise on flexibility, strength and aerobic fitness in adults with osteoarthritis of the hip or knee.

PubMed

Wang, Tsae-Jyy; Belza, Basia; Elaine Thompson, F; Whitney, Joanne D; Bennett, Kim

2007-01-01

This paper reports a study of the effects of aquatic exercise on physical fitness (flexibility, strength and aerobic fitness), self-reported physical functioning and pain in adults with osteoarthritis of the hip or knee. Osteoarthritis is a common cause of disability and a primary reason for hip and knee joint replacement. Exercise is important for preventing and/or managing the functional limitations associated with joint disease. Aquatic exercise is thought to be beneficial and is often recommended for people with osteoarthritis; however, few studies have examined the effects on people with osteoarthritis, and these have yielded inconsistent results. A two-group randomized controlled trial with a convenience sample was used. Participants were recruited from community sources and randomly assigned to a 12-week aquatic programme or a non-exercise control condition. Data for 38 participants were collected at baseline, week 6, and week 12 during 2003 and 2004. Instruments were a standard plastic goniometer, a handheld dynamometer, the 6-minute walk test, the multidimensional Health Assessment Questionnaire, and a visual analogue scale for pain. Repeated measures analysis of variance showed that aquatic exercise statistically significantly improved knee and hip flexibility, strength and aerobic fitness, but had no effect on self-reported physical functioning and pain. The exercise adherence rate was 81.7%, and no exercise-related adverse effect was observed or reported. Beneficial short-term effects of aquatic exercise were found in adults with osteoarthritis of the hip or knee. Although the programme may not offer pain relief or self-reported improvements in physical functioning, results suggest that aquatic exercise does not worsen the joint condition or result in injury. Nurses engaging in disease management and health promotion for these patients should consider recommending or implementing aquatic classes for patients.

Analysis of flexible aircraft longitudinal dynamics and handling qualities. Volume 2: Data

NASA Technical Reports Server (NTRS)

Waszak, M. R.; Schmidt, D. K.

1985-01-01

Two analysis methods are applied to a family of flexible aircraft in order to investigate how and when structural (especially dynamic aeroelastic) effects affect the dynamic characteristics of aircraft. The first type of analysis is an open loop modal analysis technique. This method considers the effect of modal residue magnitudes on determining vehicle handling qualities. The second method is a pilot in the loop analysis procedure that considers several closed loop system characteristics. Both analyses indicated that dynamic aeroelastic effects caused a degradation in vehicle tracking performance, based on the evaluation of some simulation results. Volume 2 consists of the presentation of the state variable models of the flexible aircraft configurations used in the analysis applications mode shape plots for the structural modes, numerical results from the modal analysis frequency response plots from the pilot in the loop analysis and a listing of the modal analysis computer program.

A Study of Mid-IR Laser Active Regions

DTIC Science & Technology

2003-05-01

together with the best fit obtained by using x and the layer thickness as fitting parameters. The fit, performed using the Takagi- Taupin dynamical...devices, Shun Lien Chuang, Wiley Inter. Science, 185 (1995) vii Takagi- Taupin X-ray scattering equations of dynamical diffraction, Rads Mercury v3.7, Bede

Simulation of the evolution of root water foraging strategies in dry and shallow soils

PubMed Central

Renton, Michael; Poot, Pieter

2014-01-01

Background and Aims The dynamic structural development of plants can be seen as a strategy for exploiting the limited resources available within their environment, and we would expect that evolution would lead to efficient strategies that reduce costs while maximizing resource acquisition. In particular, perennial species endemic to habitats with shallow soils in seasonally dry environments have been shown to have a specialized root system morphology that may enhance access to water resources in the underlying rock. This study aimed to explore these hypotheses by applying evolutionary algorithms to a functional–structural root growth model. Methods A simulation model of a plant's root system was developed, which represents the dynamics of water uptake and structural growth. The model is simple enough for evolutionary optimization to be computationally feasible, yet flexible enough to allow a range of structural development strategies to be explored. The model was combined with an evolutionary algorithm in order to investigate a case study habitat with a highly heterogeneous distribution of resources, both spatially and temporally – the situation of perennial plants occurring on shallow soils in seasonally dry environments. Evolution was simulated under two contrasting fitness criteria: (1) the ability to find wet cracks in underlying rock, and (2) maximizing above-ground biomass. Key Results The novel approach successfully resulted in the evolution of more efficient structural development strategies for both fitness criteria. Different rooting strategies evolved when different criteria were applied, and each evolved strategy made ecological sense in terms of the corresponding fitness criterion. Evolution selected for root system morphologies which matched those of real species from corresponding habitats. Conclusions Specialized root morphology with deeper rather than shallower lateral branching enhances access to water resources in underlying rock. More generally, the approach provides insights into both evolutionary processes and ecological costs and benefits of different plant growth strategies. PMID:24651371

Recent progress of flexible AMOLED displays

NASA Astrophysics Data System (ADS)

Pang, Huiqing; Rajan, Kamala; Silvernail, Jeff; Mandlik, Prashant; Ma, Ruiqing; Hack, Mike; Brown, Julie J.; Yoo, Juhn S.; Jung, Sang-Hoon; Kim, Yong-Cheol; Byun, Seung-Chan; Kim, Jong-Moo; Yoon, Soo-Young; Kim, Chang-Dong; Hwang, Yong-Kee; Chung, In-Jae; Fletcher, Mark; Green, Derek; Pangle, Mike; McIntyre, Jim; Smith, Randal D.

2011-03-01

Significant progress has been made in recent years in flexible AMOLED displays and numerous prototypes have been demonstrated. Replacing rigid glass with flexible substrates and thin-film encapsulation makes displays thinner, lighter, and non-breakable - all attractive features for portable applications. Flexible AMOLEDs equipped with phosphorescent OLEDs are considered one of the best candidates for low-power, rugged, full-color video applications. Recently, we have demonstrated a portable communication display device, built upon a full-color 4.3-inch HVGA foil display with a resolution of 134 dpi using an all-phosphorescent OLED frontplane. The prototype is shaped into a thin and rugged housing that will fit over a user's wrist, providing situational awareness and enabling the wearer to see real-time video and graphics information.

Dynamics in the Fitness-Income plane: Brazilian states vs World countries

PubMed Central

Operti, Felipe G.; Pugliese, Emanuele; Andrade, José S.; Pietronero, Luciano

2018-01-01

In this paper we introduce a novel algorithm, called Exogenous Fitness, to calculate the Fitness of subnational entities and we apply it to the states of Brazil. In the last decade, several indices were introduced to measure the competitiveness of countries by looking at the complexity of their export basket. Tacchella et al (2012) developed a non-monetary metric called Fitness. In this paper, after an overview about Brazil as a whole and the comparison with the other BRIC countries, we introduce a new methodology based on the Fitness algorithm, called Exogenous Fitness. Combining the results with the Gross Domestic Product per capita (GDPp), we look at the dynamics of the Brazilian states in the Fitness-Income plane. Two regimes are distinguishable: one with high predictability and the other with low predictability, showing a deep analogy with the heterogeneous dynamics of the World countries. Furthermore, we compare the ranking of the Brazilian states according to the Exogenous Fitness with the ranking obtained through two other techniques, namely Endogenous Fitness and Economic Complexity Index. PMID:29874265

Dynamics in the Fitness-Income plane: Brazilian states vs World countries.

PubMed

Operti, Felipe G; Pugliese, Emanuele; Andrade, José S; Pietronero, Luciano; Gabrielli, Andrea

2018-01-01

In this paper we introduce a novel algorithm, called Exogenous Fitness, to calculate the Fitness of subnational entities and we apply it to the states of Brazil. In the last decade, several indices were introduced to measure the competitiveness of countries by looking at the complexity of their export basket. Tacchella et al (2012) developed a non-monetary metric called Fitness. In this paper, after an overview about Brazil as a whole and the comparison with the other BRIC countries, we introduce a new methodology based on the Fitness algorithm, called Exogenous Fitness. Combining the results with the Gross Domestic Product per capita (GDPp), we look at the dynamics of the Brazilian states in the Fitness-Income plane. Two regimes are distinguishable: one with high predictability and the other with low predictability, showing a deep analogy with the heterogeneous dynamics of the World countries. Furthermore, we compare the ranking of the Brazilian states according to the Exogenous Fitness with the ranking obtained through two other techniques, namely Endogenous Fitness and Economic Complexity Index.

High-Speed Rotor Analytical Dynamics on Flexible Foundation Subjected to Internal and External Excitation

NASA Astrophysics Data System (ADS)

Jivkov, Venelin S.; Zahariev, Evtim V.

2016-12-01

The paper presents a geometrical approach to dynamics simulation of a rigid and flexible system, compiled of high speed rotating machine with eccentricity and considerable inertia and mass. The machine is mounted on a vertical flexible pillar with considerable height. The stiffness and damping of the column, as well as, of the rotor bearings and the shaft are taken into account. Non-stationary vibrations and transitional processes are analyzed. The major frequency and modal mode of the flexible column are used for analytical reduction of its mass, stiffness and damping properties. The rotor and the foundation are modelled as rigid bodies, while the flexibility of the bearings is estimated by experiments and the requirements of the manufacturer. The transition effects as a result of limited power are analyzed by asymptotic methods of averaging. Analytical expressions for the amplitudes and unstable vibrations throughout resonance are derived by quasi-static approach increasing and decreasing of the exciting frequency. Analytical functions give the possibility to analyze the influence of the design parameter of many structure applications as wind power generators, gas turbines, turbo-generators, and etc. A numerical procedure is applied to verify the effectiveness and precision of the simulation process. Nonlinear and transitional effects are analyzed and compared to the analytical results. External excitations, as wave propagation and earthquakes, are discussed. Finite elements in relative and absolute coordinates are applied to model the flexible column and the high speed rotating machine. Generalized Newton - Euler dynamics equations are used to derive the precise dynamics equations. Examples of simulation of the system vibrations and nonstationary behaviour are presented.

Flap flexibility amongst plasmepsins I, II, III, IV, and V: Sequence, structural, and molecular dynamics analyses.

PubMed

McGillewie, Lara; Soliman, Mahmoud E

2015-09-01

Herein, for the first time, we comparatively report the opening and closing of apo plasmepsin I - V. Plasmepsins belong the aspartic protease family of enzymes, and are expressed during the various stages of the P. falciparum lifecycle, the species responsible for the most lethal and virulent malaria to infect humans. Plasmepsin I, II, IV and HAP degrade hemoglobin from infected red blood cells, whereas plasmepsin V transport proteins crucial to the survival of the malaria parasite across the endoplasmic reticulum. Flap-structures covering the active site of aspartic proteases (such as HIV protease) are crucial to the conformational flexibility and dynamics of the protein, and ultimately control the binding landscape. The flap-structure in plasmepsins is made up of a flip tip in the N-terminal lying perpendicular to the active site, adjacent to the flexible loop region in the C-terminal. Using molecular dynamics, we propose three parameters to better describe the opening and closing of the flap-structure in apo plasmepsins. Namely, the distance, d1, between the flap tip and the flexible region; the dihedral angle, ϕ, to account for the twisting motion; and the TriCα angle, θ1. Simulations have shown that as the flap-structure twists, the flap and flexible region move apart opening the active site, or move toward each other closing the active site. The data from our study indicate that of all the plasmepsins investigated in the present study, Plm IV and V display the highest conformational flexibility and are more dynamic structures versus Plm I, II, and HAP. © 2015 Wiley Periodicals, Inc.

The dynamics of a flexible bladed disc on a flexible rotor in a two-rotor system

NASA Technical Reports Server (NTRS)

Gallardo, V. C.; Stallone, M. J.

1984-01-01

This paper describes the development of the analysis of the transient dynamic response of a bladed disk on a flexible rotor. The rotating flexible bladed disk is considered as a module in a complete turbine engine structure. The analysis of the flexible bladed disk (FBD) module is developed for the non-equilibrated one-diameter axial mode. The FBD motion is considered as a sum of two standing axial waves constrained to the rotor. The FBD is coupled inertially and gyroscopically to its rotor support, and indirectly through connecting elements, to the adjacent rotor and/or other supporting structures. Incorporated in the basic Turbine Engine Transient Response Analysis program (TETRA), the FBD module is demonstrated with a two-rotor model where the FBD can be excited into resonance by an unbalance in the adjacent rotor and at a frequency equal to the differential rotor speed. The FBD module also allows the analysis of two flexible bladed disks in the same rotor.

Propulsion via flexible flapping in granular media

NASA Astrophysics Data System (ADS)

Peng, Zhiwei; Ding, Yang; Pietrzyk, Kyle; Elfring, Gwynn J.; Pak, On Shun

2017-07-01

Biological locomotion in nature is often achieved by the interaction between a flexible body and its surrounding medium. The interaction of a flexible body with granular media is less understood compared with viscous fluids partially due to its complex rheological properties. In this work, we explore the effect of flexibility on granular propulsion by considering a simple mechanical model in which a rigid rod is connected to a torsional spring that is under a displacement actuation using a granular resistive force theory. Through a combined numerical and asymptotic investigation, we characterize the propulsive dynamics of such a flexible flapper in relation to the actuation amplitude and spring stiffness, and we compare these dynamics with those observed in a viscous fluid. In addition, we demonstrate that the maximum possible propulsive force can be obtained in the steady propulsion limit with a finite spring stiffness and large actuation amplitude. These results may apply to the development of synthetic locomotive systems that exploit flexibility to move through complex terrestrial media.

Assessing child belt fit, volume II : effect of restraint configuration, booster seat designs, seating procedure, and belt fit on the dynamic response of the hybrid III 10-year-old ATD in sled tests.

DOT National Transportation Integrated Search

2008-09-01

A total of 49 dynamic sled tests were performed with the Hybrid III 10YO to examine issues relating to child belt fit. The goals of these tests were to evaluate ATD response to realistic belt geometries and belt fit, develop methods for accurate, rep...

Variability of the Cyclin-Dependent Kinase 2 Flexibility Without Significant Change in the Initial Conformation of the Protein or Its Environment; a Computational Study.

PubMed

Taghizadeh, Mohammad; Goliaei, Bahram; Madadkar-Sobhani, Armin

2016-06-01

Protein flexibility, which has been referred as a dynamic behavior has various roles in proteins' functions. Furthermore, for some developed tools in bioinformatics, such as protein-protein docking software, considering the protein flexibility, causes a higher degree of accuracy. Through undertaking the present work, we have accomplished the quantification plus analysis of the variations in the human Cyclin Dependent Kinase 2 (hCDK2) protein flexibility without affecting a significant change in its initial environment or the protein per se. The main goal of the present research was to calculate variations in the flexibility for each residue of the hCDK2, analysis of their flexibility variations through clustering, and to investigate the functional aspects of the residues with high flexibility variations. Using Gromacs package (version 4.5.4), three independent molecular dynamics (MD) simulations of the hCDK2 protein (PDB ID: 1HCL) was accomplished with no significant changes in their initial environments, structures, or conformations, followed by Root Mean Square Fluctuations (RMSF) calculation of these MD trajectories. The amount of variations in these three curves of RMSF was calculated using two formulas. More than 50% of the variation in the flexibility (the distance between the maximum and the minimum amount of the RMSF) was found at the region of Val-154. As well, there are other major flexibility fluctuations in other residues. These residues were mostly positioned in the vicinity of the functional residues. The subsequent works were done, as followed by clustering all hCDK2 residues into four groups considering the amount of their variability with respect to flexibility and their position in the RMSF curves. This work has introduced a new class of flexibility aspect of the proteins' residues. It could also help designing and engineering proteins, with introducing a new dynamic aspect of hCDK2, and accordingly, for the other similar globular proteins. In addition, it could provide a better computational calculation of the protein flexibility, which is, especially important in the comparative studies of the proteins' flexibility.

Variability of the Cyclin-Dependent Kinase 2 Flexibility Without Significant Change in the Initial Conformation of the Protein or Its Environment; a Computational Study

PubMed Central

Taghizadeh, Mohammad; Goliaei, Bahram; Madadkar-Sobhani, Armin

2016-01-01

Background Protein flexibility, which has been referred as a dynamic behavior has various roles in proteins’ functions. Furthermore, for some developed tools in bioinformatics, such as protein-protein docking software, considering the protein flexibility, causes a higher degree of accuracy. Through undertaking the present work, we have accomplished the quantification plus analysis of the variations in the human Cyclin Dependent Kinase 2 (hCDK2) protein flexibility without affecting a significant change in its initial environment or the protein per se. Objectives The main goal of the present research was to calculate variations in the flexibility for each residue of the hCDK2, analysis of their flexibility variations through clustering, and to investigate the functional aspects of the residues with high flexibility variations. Materials and Methods Using Gromacs package (version 4.5.4), three independent molecular dynamics (MD) simulations of the hCDK2 protein (PDB ID: 1HCL) was accomplished with no significant changes in their initial environments, structures, or conformations, followed by Root Mean Square Fluctuations (RMSF) calculation of these MD trajectories. The amount of variations in these three curves of RMSF was calculated using two formulas. Results More than 50% of the variation in the flexibility (the distance between the maximum and the minimum amount of the RMSF) was found at the region of Val-154. As well, there are other major flexibility fluctuations in other residues. These residues were mostly positioned in the vicinity of the functional residues. The subsequent works were done, as followed by clustering all hCDK2 residues into four groups considering the amount of their variability with respect to flexibility and their position in the RMSF curves. Conclusions This work has introduced a new class of flexibility aspect of the proteins’ residues. It could also help designing and engineering proteins, with introducing a new dynamic aspect of hCDK2, and accordingly, for the other similar globular proteins. In addition, it could provide a better computational calculation of the protein flexibility, which is, especially important in the comparative studies of the proteins’ flexibility. PMID:28959320

The effects of wing flexibility on the flight performance and stability of flapping wing micro air vehicles

NASA Astrophysics Data System (ADS)

Bluman, James Edward

Insect wings are flexible. However, the influence of wing flexibility on the flight dynamics of insects and flapping wing micro air vehicles is unknown. Most studies in the literature consider rigid wings and conclude that the hover equilibrium is unstable. This dissertation shows that a flapping wing flyer with flexible wings exhibits stable natural modes of the open loop system in hover, never reported before. The free-flight insect flight dynamics is modeled for both flexible and rigid wings. Wing mass and inertia are included in the nonlinear equations of motion. The flapping wing aerodynamics are modeled using a quasi-steady model, a well-validated two dimensional Navier Stokes model, and a coupled, two dimensional Navier Stokes - Euler Bernoulli beam model that accurately models the fluid-structure interaction of flexible wings. Hover equilibrium is systematically and efficiently determined with a coupled quasi-steady and Navier-Stokes equation trimmer. The power and stability are reported at hover while parametrically varying the pitch axis location for rigid wings and the structural stiffness for flexible wings. The results indicate that the rigid wings possess an unstable oscillatory mode mainly due to their pitch sensitivity to horizontal velocity perturbations. The flexible wings stabilize this mode primarily by adjusting their wing shape in the presence of perturbations. The wing's response to perturbations generates significantly more horizontal velocity damping and pitch rate damping than in rigid wings. Furthermore, the flexible wings experience substantially less wing wake interaction, which, for rigid wings, is destabilizing. The power required to hover a fruit fly with actively rotating rigid wings varies between 16.9 and 34.2 W/kg. The optimal power occurs when the pitch axis is located at 30% chord, similar to some biological observations. Flexible wings require 23.1 to 38.5 W/kg. However, flexible wings exhibit more stable system dynamics and allow for simpler and lighter designs since they do not require pitch actuation mechanisms. This study is the first to evaluate the impact of wing flexibility on the hovering stability of flapping flyers, which can explain the ranges of flexibility seen in insects and can inform designs of synthetic flapping wing robots.

Steady-state structural fluctuation is a predictor of the necessity of pausing-mediated co-translational folding for small proteins.

PubMed

Huang, Wenxi; Liu, Wanting; Jin, Jingjie; Xiao, Qilan; Lu, Ruibin; Chen, Wei; Xiong, Sheng; Zhang, Gong

2018-03-25

Translational pausing coordinates protein synthesis and co-translational folding. It is a common factor that facilitates the correct folding of large, multi-domain proteins. For small proteins, pausing sites rarely occurs in the gene body, and the 3'-end pausing sites are only essential for the folding of a fraction of proteins. The determinant of the necessity of the pausings remains obscure. In this study, we demonstrated that the steady-state structural fluctuation is a predictor of the necessity of pausing-mediated co-translational folding for small proteins. Validated by experiments with 5 model proteins, we found that the rigid protein structures do not, while the flexible structures do need 3'-end pausings to fold correctly. Therefore, rational optimization of translational pausing can improve soluble expression of small proteins with flexible structures, but not the rigid ones. The rigidity of the structure can be quantitatively estimated in silico using molecular dynamic simulation. Nevertheless, we also found that the translational pausing optimization increases the fitness of the expression host, and thus benefits the recombinant protein production, independent from the soluble expression. These results shed light on the structural basis of the translational pausing and provided a practical tool for industrial protein fermentation. Copyright © 2017. Published by Elsevier Inc.

Dynamic characterization, monitoring and control of rotating flexible beam-mass structures via piezo-embedded techniques

NASA Technical Reports Server (NTRS)

Lai, Steven H.-Y.

1992-01-01

A variational principle and a finite element discretization technique were used to derive the dynamic equations for a high speed rotating flexible beam-mass system embedded with piezo-electric materials. The dynamic equation thus obtained allows the development of finite element models which accommodate both the original structural element and the piezoelectric element. The solutions of finite element models provide system dynamics needed to design a sensing system. The characterization of gyroscopic effect and damping capacity of smart rotating devices are addressed. Several simulation examples are presented to validate the analytical solution.

Fluid Dynamics of Clap-and-Fling with Highly Flexible Wings inspired by the Locomotion of Sea Butterflies

NASA Astrophysics Data System (ADS)

Zhou, Zhuoyu; Shoele, Kourosh; Adhikari, Deepak; Yen, Jeannette; Webster, Donald; Mittal, Rajat; Johns Hopkins University Team; Georgia Institute of Technology Team

2015-11-01

This study is motivated by the locomotion of sea butterflies (L. Helicina) which propel themselves in the water column using highly flexible wing-like parapodia. These animals execute a complex clap-and-fling with their highly flexible wings that is different from that of insects, and the fluid dynamics of which is not well understood. We use two models to study the fluid dyamics of these wings. In the first, we use prescribed wing kinematics that serve as a model of those observed for these animals. The second model is a fluid-structure interaction model where wing-like parapodia are modeled as flexible but inextensible membranes. The membrane properties, such as bending and stretching stiffness are modified such that the corresponding motion qualitatively matches the kinematics of L. helicina. Both models are used to examine the fluid dynamics of the clap-and-fling and its effectiveness in generating lift for these animals. Acknowledgement - research is supported by a grant from NSF.

All-atom molecular dynamics of the HBV capsid reveals insights into biological function and cryo-EM resolution limits

PubMed Central

Perilla, Juan R; Schlicksup, Christopher John; Venkatakrishnan, Balasubramanian; Zlotnick, Adam; Schulten, Klaus

2018-01-01

The hepatitis B virus capsid represents a promising therapeutic target. Experiments suggest the capsid must be flexible to function; however, capsid structure and dynamics have not been thoroughly characterized in the absence of icosahedral symmetry constraints. Here, all-atom molecular dynamics simulations are leveraged to investigate the capsid without symmetry bias, enabling study of capsid flexibility and its implications for biological function and cryo-EM resolution limits. Simulation results confirm flexibility and reveal a propensity for asymmetric distortion. The capsid’s influence on ionic species suggests a mechanism for modulating the display of cellular signals and implicates the capsid’s triangular pores as the location of signal exposure. A theoretical image reconstruction performed using simulated conformations indicates how capsid flexibility may limit the resolution of cryo-EM. Overall, the present work provides functional insight beyond what is accessible to experimental methods and raises important considerations regarding asymmetry in structural studies of icosahedral virus capsids. PMID:29708495

Vibration and stability of cracked hollow-sectional beams

NASA Astrophysics Data System (ADS)

Zheng, D. Y.; Fan, S. C.

2003-10-01

This paper presents simple tools for the vibration and stability analysis of cracked hollow-sectional beams. It comprises two parts. In the first, the influences of sectional cracks are expressed in terms of flexibility induced. Each crack is assigned with a local flexibility coefficient, which is derived by virtue of theories of fracture mechanics. The flexibility coefficient is a function of the depth of a crack. The general formulae are derived and expressed in integral form. It is then transformed to explicit form through 128-point Gauss quadrature. According to the depth of the crack, the formulae are derived under two scenarios. The first is for shallow cracks, of which the penetration depth is contained within the top solid-sectional region. The second is for deeper penetration, in which the crack goes into the middle hollow-sectional region. The explicit formulae are best-fitted equations generated by the least-squares method. The best-fitted curves are presented. From the curves, the flexibility coefficients can be read out easily, while the explicit expressions facilitate easy implementation in computer analysis. In the second part, the flexibility coefficients are employed in the vibration and stability analysis of hollow-sectional beams. The cracked beam is treated as an assembly of sub-segments linked up by rotational springs. Division of segments are made coincident with the location of cracks or any abrupt change of sectional property. The crack's flexibility coefficient then serves as that of the rotational spring. Application of the Hamilton's principle leads to the governing equations, which are subsequently solved through employment of a simple technique. It is a kind of modified Fourier series, which is able to represent any order of continuity of the vibration/buckling modes. Illustrative numerical examples are included.

A Systematic Review of the Association Between Physical Fitness and Musculoskeletal Injury Risk: Part 3 - Flexibility, Power, Speed, Balance, and Agility.

PubMed

de la Motte, Sarah J; Lisman, Peter; Gribbin, Timothy C; Murphy, Kaitlin; Deuster, Patricia A

2017-12-11

We performed a systematic review and evaluation of the existing scientific literature on the association between flexibility, power, speed, balance, and agility, and musculoskeletal injury (MSK-I) risk in military and civilian populations. MEDLINE, EBSCO, EMBASE, and the Defense Technical Information Center were searched for original studies published from 1970 through 2015 that examined associations between these physical fitness measures (flexibility, power, speed, balance, and agility) and MSK-I. Methodological quality and strength of the evidence were determined following criteria adapted from previously published systematic reviews. Twenty-seven of 4,229 citations met our inclusion criteria. Primary findings indicate there is (a) moderate evidence that hamstring flexibility, as measured by performance on a sit-and-reach test or active straight-leg raise test assessed with goniometry, and ankle flexibility, assessed with goniometry, are associated with MSK-I risk; (b) moderate evidence that lower body power, as measured by performance on a standing broad jump or vertical jump with no countermovement, is associated with MSK-I risk; (c) moderate evidence that slow sprint speed is associated with MSK-I risk; (d) moderate evidence that poor performance on a single-leg balance test is associated with increased risk for ankle sprain; and (e) insufficient evidence that agility is associated with MSK-I risk. Several measures of flexibility, power, speed, and balance are risk factors for training-related MSK-I in military and civilian athletic populations. Importantly, these findings can be useful for military, first responder, and athletic communities who are seeking evidence-based metrics for assessing or stratifying populations for risk of MSK-I.

Effect of manual therapy versus proprioceptive neuromuscular facilitation in dynamic balance, mobility and flexibility in field hockey players. A randomized controlled trial.

PubMed

Espí-López, Gemma V; López-Martínez, Susana; Inglés, Marta; Serra-Añó, Pilar; Aguilar-Rodríguez, Marta

2018-04-22

To compare the effectiveness of a specific Manual Therapy (MT) protocol applied to field hockey players (FHP), versus a Proprioceptive Neuromuscular Facilitation (PNF) protocol, in the improvement of dynamic balance, active range of movement and lumbar flexibility one-week and four-weeks after the treatment. Randomized controlled trial. Participants were assigned to 2 groups: MT and PNF. 30 min' sessions were performed once a week for three weeks. Three evaluations were performed: basal, one-week and four-weeks post-treatment. University of Valencia (Spain). 22 in MT group and 20 in PNF group. Dynamic Balance, measured with Star Excursion Balance Test; Active Range of Motion (ROM), using a manual goniometer and Lumbar Flexibility, assessed with Fingertip-to-floor test. Both groups significantly improved in lateral and medial dynamic balance one-week post-treatment (p < 0.05); but the improvement in the MT group lasted until the fourth-week after treatment in both reaches (lateral and medial) (p < 0.05). MT group also obtained significant improvements in dorsal flexion of the ankle in the fourth-week post-treatment (p < 0.05) and in lumbar flexibility one-week post-treatment (p < 0.05). MT and PNF improve dynamic balance one-week post-treatment; however, the improvement obtained through MT is maintained four-weeks later. Only MT improves dorsal flexion of the ankle four-weeks post-treatment and lumbar flexibility one-week post-treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

A mechanistic stress model of protein evolution accounts for site-specific evolutionary rates and their relationship with packing density and flexibility

PubMed Central

2014-01-01

Background Protein sites evolve at different rates due to functional and biophysical constraints. It is usually considered that the main structural determinant of a site’s rate of evolution is its Relative Solvent Accessibility (RSA). However, a recent comparative study has shown that the main structural determinant is the site’s Local Packing Density (LPD). LPD is related with dynamical flexibility, which has also been shown to correlate with sequence variability. Our purpose is to investigate the mechanism that connects a site’s LPD with its rate of evolution. Results We consider two models: an empirical Flexibility Model and a mechanistic Stress Model. The Flexibility Model postulates a linear increase of site-specific rate of evolution with dynamical flexibility. The Stress Model, introduced here, models mutations as random perturbations of the protein’s potential energy landscape, for which we use simple Elastic Network Models (ENMs). To account for natural selection we assume a single active conformation and use basic statistical physics to derive a linear relationship between site-specific evolutionary rates and the local stress of the mutant’s active conformation. We compare both models on a large and diverse dataset of enzymes. In a protein-by-protein study we found that the Stress Model outperforms the Flexibility Model for most proteins. Pooling all proteins together we show that the Stress Model is strongly supported by the total weight of evidence. Moreover, it accounts for the observed nonlinear dependence of sequence variability on flexibility. Finally, when mutational stress is controlled for, there is very little remaining correlation between sequence variability and dynamical flexibility. Conclusions We developed a mechanistic Stress Model of evolution according to which the rate of evolution of a site is predicted to depend linearly on the local mutational stress of the active conformation. Such local stress is proportional to LPD, so that this model explains the relationship between LPD and evolutionary rate. Moreover, the model also accounts for the nonlinear dependence between evolutionary rate and dynamical flexibility. PMID:24716445

Meta-analysis of Gaussian individual patient data: Two-stage or not two-stage?

PubMed

Morris, Tim P; Fisher, David J; Kenward, Michael G; Carpenter, James R

2018-04-30

Quantitative evidence synthesis through meta-analysis is central to evidence-based medicine. For well-documented reasons, the meta-analysis of individual patient data is held in higher regard than aggregate data. With access to individual patient data, the analysis is not restricted to a "two-stage" approach (combining estimates and standard errors) but can estimate parameters of interest by fitting a single model to all of the data, a so-called "one-stage" analysis. There has been debate about the merits of one- and two-stage analysis. Arguments for one-stage analysis have typically noted that a wider range of models can be fitted and overall estimates may be more precise. The two-stage side has emphasised that the models that can be fitted in two stages are sufficient to answer the relevant questions, with less scope for mistakes because there are fewer modelling choices to be made in the two-stage approach. For Gaussian data, we consider the statistical arguments for flexibility and precision in small-sample settings. Regarding flexibility, several of the models that can be fitted only in one stage may not be of serious interest to most meta-analysis practitioners. Regarding precision, we consider fixed- and random-effects meta-analysis and see that, for a model making certain assumptions, the number of stages used to fit this model is irrelevant; the precision will be approximately equal. Meta-analysts should choose modelling assumptions carefully. Sometimes relevant models can only be fitted in one stage. Otherwise, meta-analysts are free to use whichever procedure is most convenient to fit the identified model. © 2018 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

A systematic study of multiple minerals precipitation modelling in wastewater treatment.

PubMed

Kazadi Mbamba, Christian; Tait, Stephan; Flores-Alsina, Xavier; Batstone, Damien J

2015-11-15

Mineral solids precipitation is important in wastewater treatment. However approaches to minerals precipitation modelling are varied, often empirical, and mostly focused on single precipitate classes. A common approach, applicable to multi-species precipitates, is needed to integrate into existing wastewater treatment models. The present study systematically tested a semi-mechanistic modelling approach, using various experimental platforms with multiple minerals precipitation. Experiments included dynamic titration with addition of sodium hydroxide to synthetic wastewater, and aeration to progressively increase pH and induce precipitation in real piggery digestate and sewage sludge digestate. The model approach consisted of an equilibrium part for aqueous phase reactions and a kinetic part for minerals precipitation. The model was fitted to dissolved calcium, magnesium, total inorganic carbon and phosphate. Results indicated that precipitation was dominated by the mineral struvite, forming together with varied and minor amounts of calcium phosphate and calcium carbonate. The model approach was noted to have the advantage of requiring a minimal number of fitted parameters, so the model was readily identifiable. Kinetic rate coefficients, which were statistically fitted, were generally in the range 0.35-11.6 h(-1) with confidence intervals of 10-80% relative. Confidence regions for the kinetic rate coefficients were often asymmetric with model-data residuals increasing more gradually with larger coefficient values. This suggests that a large kinetic coefficient could be used when actual measured data is lacking for a particular precipitate-matrix combination. Correlation between the kinetic rate coefficients of different minerals was low, indicating that parameter values for individual minerals could be independently fitted (keeping all other model parameters constant). Implementation was therefore relatively flexible, and would be readily expandable to include other minerals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Health-Related Physical Fitness in Healthy Untrained Men: Effects on VO2max, Jump Performance and Flexibility of Soccer and Moderate-Intensity Continuous Running.

PubMed

Milanović, Zoran; Pantelić, Saša; Sporiš, Goran; Mohr, Magni; Krustrup, Peter

2015-01-01

The purpose of this study was to determine the effects of recreational soccer (SOC) compared to moderate-intensity continuous running (RUN) on all health-related physical fitness components in healthy untrained men. Sixty-nine participants were recruited and randomly assigned to one of three groups, of which sixty-four completed the study: a soccer training group (SOC; n = 20, 34±4 (means±SD) years, 78.1±8.3 kg, 179±4 cm); a running group (RUN; n = 21, 32±4 years, 78.0±5.5 kg, 179±7 cm); or a passive control group (CON; n = 23, 30±3 years, 76.6±12.0 kg, 178±8 cm). The training intervention lasted 12 weeks and consisted of three 60-min sessions per week. All participants were tested for each of the following physical fitness components: maximal aerobic power, minute ventilation, maximal heart rate, squat jump (SJ), countermovement jump with arm swing (CMJ), sit-and-reach flexibility, and body composition. Over the 12 weeks, VO2max relative to body weight increased more (p<0.05) in SOC (24.2%, ES = 1.20) and RUN (21.5%, ES = 1.17) than in CON (-5.0%, ES = -0.24), partly due to large changes in body mass (-5.9, -5.7 and +2.6 kg, p<0.05 for SOC, RUN and CON, respectively). Over the 12 weeks, SJ and CMJ performance increased more (p<0.05) in SOC (14.8 and 12.1%, ES = 1.08 and 0.81) than in RUN (3.3 and 3.0%, ES = 0.23 and 0.19) and CON (0.3 and 0.2%), while flexibility also increased more (p<0.05) in SOC (94%, ES = 0.97) than in RUN and CON (0-2%). In conclusion, untrained men displayed marked improvements in maximal aerobic power after 12 weeks of soccer training and moderate-intensity running, partly due to large decreases in body mass. Additionally soccer training induced pronounced positive effects on jump performance and flexibility, making soccer an effective broad-spectrum fitness training intervention.

Dynamic bending of bionic flexible body driven by pneumatic artificial muscles(PAMs) for spinning gait of quadruped robot

NASA Astrophysics Data System (ADS)

Lei, Jingtao; Yu, Huangying; Wang, Tianmiao

2016-01-01

The body of quadruped robot is generally developed with the rigid structure. The mobility of quadruped robot depends on the mechanical properties of the body mechanism. It is difficult for quadruped robot with rigid structure to achieve better mobility walking or running in the unstructured environment. A kind of bionic flexible body mechanism for quadruped robot is proposed, which is composed of one bionic spine and four pneumatic artificial muscles(PAMs). This kind of body imitates the four-legged creatures' kinematical structure and physical properties, which has the characteristic of changeable stiffness, lightweight, flexible and better bionics. The kinematics of body bending is derived, and the coordinated movement between the flexible body and legs is analyzed. The relationship between the body bending angle and the PAM length is obtained. The dynamics of the body bending is derived by the floating coordinate method and Lagrangian method, and the driving force of PAM is determined. The experiment of body bending is conducted, and the dynamic bending characteristic of bionic flexible body is evaluated. Experimental results show that the bending angle of the bionic flexible body can reach 18°. An innovation body mechanism for quadruped robot is proposed, which has the characteristic of flexibility and achieve bending by changing gas pressure of PAMs. The coordinated movement of the body and legs can achieve spinning gait in order to improve the mobility of quadruped robot.

Exploiting the Adaptation Dynamics to Predict the Distribution of Beneficial Fitness Effects

PubMed Central

2016-01-01

Adaptation of asexual populations is driven by beneficial mutations and therefore the dynamics of this process, besides other factors, depends on the distribution of beneficial fitness effects. It is known that on uncorrelated fitness landscapes, this distribution can only be of three types: truncated, exponential and power law. We performed extensive stochastic simulations to study the adaptation dynamics on rugged fitness landscapes, and identified two quantities that can be used to distinguish the underlying distribution of beneficial fitness effects. The first quantity studied here is the fitness difference between successive mutations that spread in the population, which is found to decrease in the case of truncated distributions, remains nearly a constant for exponentially decaying distributions and increases when the fitness distribution decays as a power law. The second quantity of interest, namely, the rate of change of fitness with time also shows quantitatively different behaviour for different beneficial fitness distributions. The patterns displayed by the two aforementioned quantities are found to hold good for both low and high mutation rates. We discuss how these patterns can be exploited to determine the distribution of beneficial fitness effects in microbial experiments. PMID:26990188

Handling qualities of large flexible control-configured aircraft

NASA Technical Reports Server (NTRS)

Swaim, R. L.

1979-01-01

The approach to an analytical study of flexible airplane longitudinal handling qualities was to parametrically vary the natural frequencies of two symmetric elastic modes to induce mode interactions with the rigid body dynamics. Since the structure of the pilot model was unknown for such dynamic interactions, the optimal control pilot modeling method is being applied and used in conjunction with pilot rating method.

A computational procedure for multibody systems including flexible beam dynamics

NASA Technical Reports Server (NTRS)

Downer, J. D.; Park, K. C.; Chiou, J. C.

1990-01-01

A computational procedure suitable for the solution of equations of motions for flexible multibody systems has been developed. A fully nonlinear continuum approach capable of accounting for both finite rotations and large deformations has been used to model a flexible beam component. The beam kinematics are referred directly to an inertial reference frame such that the degrees of freedom embody both the rigid and flexible deformation motions. As such, the beam inertia expression is identical to that of rigid body dynamics. The nonlinear coupling between gross body motion and elastic deformation is contained in the internal force expression. Numerical solution procedures for the integration of spatial kinematic systems can be directily applied to the generalized coordinates of both the rigid and flexible components. An accurate computation of the internal force term which is invariant to rigid motions is incorporated into the general solution procedure.

Statistical ecology comes of age.

PubMed

Gimenez, Olivier; Buckland, Stephen T; Morgan, Byron J T; Bez, Nicolas; Bertrand, Sophie; Choquet, Rémi; Dray, Stéphane; Etienne, Marie-Pierre; Fewster, Rachel; Gosselin, Frédéric; Mérigot, Bastien; Monestiez, Pascal; Morales, Juan M; Mortier, Frédéric; Munoz, François; Ovaskainen, Otso; Pavoine, Sandrine; Pradel, Roger; Schurr, Frank M; Thomas, Len; Thuiller, Wilfried; Trenkel, Verena; de Valpine, Perry; Rexstad, Eric

2014-12-01

The desire to predict the consequences of global environmental change has been the driver towards more realistic models embracing the variability and uncertainties inherent in ecology. Statistical ecology has gelled over the past decade as a discipline that moves away from describing patterns towards modelling the ecological processes that generate these patterns. Following the fourth International Statistical Ecology Conference (1-4 July 2014) in Montpellier, France, we analyse current trends in statistical ecology. Important advances in the analysis of individual movement, and in the modelling of population dynamics and species distributions, are made possible by the increasing use of hierarchical and hidden process models. Exciting research perspectives include the development of methods to interpret citizen science data and of efficient, flexible computational algorithms for model fitting. Statistical ecology has come of age: it now provides a general and mathematically rigorous framework linking ecological theory and empirical data.

The structure of human tripeptidyl peptidase II as determined by a hybrid approach.

PubMed

Schönegge, Anne-Marie; Villa, Elizabeth; Förster, Friedrich; Hegerl, Reiner; Peters, Jürgen; Baumeister, Wolfgang; Rockel, Beate

2012-04-04

Tripeptidyl-peptidase II (TPPII) is a high molecular mass (∼5 MDa) serine protease, which is thought to act downstream of the 26S proteasome, cleaving peptides released by the latter. Here, the structure of human TPPII (HsTPPII) has been determined to subnanometer resolution by cryoelectron microscopy and single-particle analysis. The complex is built from two strands forming a quasihelical structure harboring a complex system of inner cavities. HsTPPII particles exhibit some polymorphism resulting in complexes consisting of nine or of eight dimers per strand. To obtain deeper insights into the architecture and function of HsTPPII, we have created a pseudoatomic structure of the HsTPPII spindle using a comparative model of HsTPPII dimers and molecular dynamics flexible fitting. Analyses of the resulting hybrid structure of the HsTPPII holocomplex provide new insights into the mechanism of maturation and activation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Statistical ecology comes of age

PubMed Central

Gimenez, Olivier; Buckland, Stephen T.; Morgan, Byron J. T.; Bez, Nicolas; Bertrand, Sophie; Choquet, Rémi; Dray, Stéphane; Etienne, Marie-Pierre; Fewster, Rachel; Gosselin, Frédéric; Mérigot, Bastien; Monestiez, Pascal; Morales, Juan M.; Mortier, Frédéric; Munoz, François; Ovaskainen, Otso; Pavoine, Sandrine; Pradel, Roger; Schurr, Frank M.; Thomas, Len; Thuiller, Wilfried; Trenkel, Verena; de Valpine, Perry; Rexstad, Eric

2014-01-01

The desire to predict the consequences of global environmental change has been the driver towards more realistic models embracing the variability and uncertainties inherent in ecology. Statistical ecology has gelled over the past decade as a discipline that moves away from describing patterns towards modelling the ecological processes that generate these patterns. Following the fourth International Statistical Ecology Conference (1–4 July 2014) in Montpellier, France, we analyse current trends in statistical ecology. Important advances in the analysis of individual movement, and in the modelling of population dynamics and species distributions, are made possible by the increasing use of hierarchical and hidden process models. Exciting research perspectives include the development of methods to interpret citizen science data and of efficient, flexible computational algorithms for model fitting. Statistical ecology has come of age: it now provides a general and mathematically rigorous framework linking ecological theory and empirical data. PMID:25540151

Physical Fitness and Metabolic Syndrome in Children with Repaired Congenital Heart Disease Compared with Healthy Children.

PubMed

Zaqout, Mahmoud; Vandekerckhove, Kristof; Michels, Nathalie; Bove, Thierry; François, Katrien; De Wolf, Daniel

2017-12-01

To determine whether children who underwent surgery for congenital heart disease (CHD) are as fit as their peers. We studied 66 children (6-14 years) who underwent surgery for ventricular septal defect (n = 19), coarctation of aorta (n = 10), tetralogy of Fallot (n = 15), and transposition of great arteries (n = 22); and 520 healthy children (6-12 years). All children performed physical fitness tests: cardiorespiratory fitness, muscular strength, balance, flexibility, and speed. Metabolic score was assessed through z-score standardization using 4 components: waist circumference, blood pressure, blood lipids, and insulin resistance. Assessment also included self-reported and accelerometer-measured physical activity. Linear regression analyses with group (CHD vs control) as a predictor were adjusted for age, body mass index, physical activity, and parental education. Measured physical activity level, body mass index, cardiorespiratory fitness, flexibility, and total metabolic score did not differ between children with CHD and controls, whereas reported physical activity was greater in the CHD group than control group. Boys with CHD were less strong in upper muscular strength, speed, and balance, whereas girls with CHD were better in lower muscular strength and worse in balance. High-density lipoprotein was greater in boys and girls with CHD, whereas boys with CHD showed unhealthier glucose homeostasis. Appropriate physical fitness was achieved in children after surgery for CHD, especially in girls. Consequently, children with CHD were not at increased total metabolic risk. Lifestyle counseling should be part of every patient interaction. Copyright © 2017 Elsevier Inc. All rights reserved.

"Plyo Play": A Novel Program of Short Bouts of Moderate and High Intensity Exercise Improves Physical Fitness in Elementary School Children

ERIC Educational Resources Information Center

Faigenbaum, Avery D.; Farrell, Anne C.; Radler, Tracy; Zbojovsky, Dan; Chu, Donald A.; Ratamess, Nicholas A.; Kang, Jie; Hoffman, Jay R.

2009-01-01

The purpose of this study was to examine the effects of a school-based plyometric training program (i.e., Plyo Play) on children's fitness performance. Forty children (8 to 11 yrs) participated in the program and 34 age-matched children served as controls. Performance of the long jump, sit and reach flexibility, abdominal curl, push-up, shuttle…

Plaster core washout tool

NASA Technical Reports Server (NTRS)

Heisman, R. M.; Keir, A. R.; Teramura, K.

1977-01-01

Tool powered by pressurized water or air removes water soluble plaster lining from Kevlar/epoxy duct. Rotating plastic cutterhead with sealed end fitting connects flexible shaft that allows tool to be used with curved ducts.

Exploring the Pareto frontier using multisexual evolutionary algorithms: an application to a flexible manufacturing problem

NASA Astrophysics Data System (ADS)

Bonissone, Stefano R.; Subbu, Raj

2002-12-01

In multi-objective optimization (MOO) problems we need to optimize many possibly conflicting objectives. For instance, in manufacturing planning we might want to minimize the cost and production time while maximizing the product's quality. We propose the use of evolutionary algorithms (EAs) to solve these problems. Solutions are represented as individuals in a population and are assigned scores according to a fitness function that determines their relative quality. Strong solutions are selected for reproduction, and pass their genetic material to the next generation. Weak solutions are removed from the population. The fitness function evaluates each solution and returns a related score. In MOO problems, this fitness function is vector-valued, i.e. it returns a value for each objective. Therefore, instead of a global optimum, we try to find the Pareto-optimal or non-dominated frontier. We use multi-sexual EAs with as many genders as optimization criteria. We have created new crossover and gender assignment functions, and experimented with various parameters to determine the best setting (yielding the highest number of non-dominated solutions.) These experiments are conducted using a variety of fitness functions, and the algorithms are later evaluated on a flexible manufacturing problem with total cost and time minimization objectives.

Bayesian dynamic regression models for interval censored survival data with application to children dental health.

PubMed

Wang, Xiaojing; Chen, Ming-Hui; Yan, Jun

2013-07-01

Cox models with time-varying coefficients offer great flexibility in capturing the temporal dynamics of covariate effects on event times, which could be hidden from a Cox proportional hazards model. Methodology development for varying coefficient Cox models, however, has been largely limited to right censored data; only limited work on interval censored data has been done. In most existing methods for varying coefficient models, analysts need to specify which covariate coefficients are time-varying and which are not at the time of fitting. We propose a dynamic Cox regression model for interval censored data in a Bayesian framework, where the coefficient curves are piecewise constant but the number of pieces and the jump points are covariate specific and estimated from the data. The model automatically determines the extent to which the temporal dynamics is needed for each covariate, resulting in smoother and more stable curve estimates. The posterior computation is carried out via an efficient reversible jump Markov chain Monte Carlo algorithm. Inference of each coefficient is based on an average of models with different number of pieces and jump points. A simulation study with three covariates, each with a coefficient of different degree in temporal dynamics, confirmed that the dynamic model is preferred to the existing time-varying model in terms of model comparison criteria through conditional predictive ordinate. When applied to a dental health data of children with age between 7 and 12 years, the dynamic model reveals that the relative risk of emergence of permanent tooth 24 between children with and without an infected primary predecessor is the highest at around age 7.5, and that it gradually reduces to one after age 11. These findings were not seen from the existing studies with Cox proportional hazards models.

Flexible Virtual Structure Consideration in Dynamic Modeling of Mobile Robots Formation

NASA Astrophysics Data System (ADS)

El Kamel, A. Essghaier; Beji, L.; Lerbet, J.; Abichou, A.

2009-03-01

In cooperative mobile robotics, we look for formation keeping and maintenance of a geometric configuration during movement. As a solution to these problems, the concept of a virtual structure is considered. Based on this idea, we have developed an efficient flexible virtual structure, describing the dynamic model of n vehicles in formation and where the whole formation is kept dependant. Notes that, for 2D and 3D space navigation, only a rigid virtual structure was proposed in the literature. Further, the problem was limited to a kinematic behavior of the structure. Hence, the flexible virtual structure in dynamic modeling of mobile robots formation presented in this paper, gives more capabilities to the formation to avoid obstacles in hostile environment while keeping formation and avoiding inter-agent collision.

Imfit: A Fast, Flexible Program for Astronomical Image Fitting

NASA Astrophysics Data System (ADS)

Erwin, Peter

2014-08-01

Imift is an open-source astronomical image-fitting program specialized for galaxies but potentially useful for other sources, which is fast, flexible, and highly extensible. Its object-oriented design allows new types of image components (2D surface-brightness functions) to be easily written and added to the program. Image functions provided with Imfit include Sersic, exponential, and Gaussian galaxy decompositions along with Core-Sersic and broken-exponential profiles, elliptical rings, and three components that perform line-of-sight integration through 3D luminosity-density models of disks and rings seen at arbitrary inclinations. Available minimization algorithms include Levenberg-Marquardt, Nelder-Mead simplex, and Differential Evolution, allowing trade-offs between speed and decreased sensitivity to local minima in the fit landscape. Minimization can be done using the standard chi^2 statistic (using either data or model values to estimate per-pixel Gaussian errors, or else user-supplied error images) or the Cash statistic; the latter is particularly appropriate for cases of Poisson data in the low-count regime. The C++ source code for Imfit is available under the GNU Public License.

The relationship between physical activity and physical self-esteem in adolescents: the role of physical fitness indices.

PubMed

Haugen, Tommy; Ommundsen, Yngvar; Seiler, Stephen

2013-02-01

The aim of this study was to investigate if physical fitness (strength/power, endurance, flexibility and coordination) mediates the cross-sectional relationship between physical activity and physical self-perception (athletic competence and physical appearance) in a sample of 15-year old adolescents. We wanted to investigate the relative strength of each indirect effect. The present data are taken from two waves of a larger data collection for the project "Youth in Balance", and was collected in the autumn of 2005 (N = 1207) and 2008 (N = 632). A total of 1839 students (889 girls and 950 boys) from 12 schools in Kristiansand took part. A bias-corrected bootstrapping technique was used to examine indirect effects. Results revealed that cardiovascular endurance, lower-body strength/power, and upper-body strength stood out as unique mediators in the relationship between physical activity and athletic competence in both genders. Furthermore, there was an indirect effect of physical activity on physical appearance through physical strength/power and flexibility in males. No indirect effects of physical activity on physical appearance through actual physical fitness indices were detected in females.

Transient dynamics of a flexible rotor with squeeze film dampers

NASA Technical Reports Server (NTRS)

Buono, D. F.; Schlitzer, L. D.; Hall, R. G., III; Hibner, D. H.

1978-01-01

A series of simulated blade loss tests are reported on a test rotor designed to operate above its second bending critical speed. A series of analyses were performed which predicted the transient behavior of the test rig for each of the blade loss tests. The scope of the program included the investigation of transient rotor dynamics of a flexible rotor system, similar to modern flexible jet engine rotors, both with and without squeeze film dampers. The results substantiate the effectiveness of squeeze film dampers and document the ability of available analytical methods to predict their effectiveness and behavior.

A digital computer program for the dynamic interaction simulation of controls and structure (DISCOS), volume 1

NASA Technical Reports Server (NTRS)

Bodley, C. S.; Devers, A. D.; Park, A. C.; Frisch, H. P.

1978-01-01

A theoretical development and associated digital computer program system for the dynamic simulation and stability analysis of passive and actively controlled spacecraft are presented. The dynamic system (spacecraft) is modeled as an assembly of rigid and/or flexible bodies not necessarily in a topological tree configuration. The computer program system is used to investigate total system dynamic characteristics, including interaction effects between rigid and/or flexible bodies, control systems, and a wide range of environmental loadings. In addition, the program system is used for designing attitude control systems and for evaluating total dynamic system performance, including time domain response and frequency domain stability analyses.

Genetic algorithm dynamics on a rugged landscape

NASA Astrophysics Data System (ADS)

Bornholdt, Stefan

1998-04-01

The genetic algorithm is an optimization procedure motivated by biological evolution and is successfully applied to optimization problems in different areas. A statistical mechanics model for its dynamics is proposed based on the parent-child fitness correlation of the genetic operators, making it applicable to general fitness landscapes. It is compared to a recent model based on a maximum entropy ansatz. Finally it is applied to modeling the dynamics of a genetic algorithm on the rugged fitness landscape of the NK model.

The Moderating Effects of IT Training Programs: A Study of IT Flexibility Investments

ERIC Educational Resources Information Center

Plickebaum, Terry L.

2012-01-01

Information technology (IT) flexibility continues to grow in importance as organizations become increasingly dependent on IT in increasingly dynamic business environments. The contribution of IT infrastructure towards IT flexibility is fairly well understood and managed within organizations today. The contribution of IT personnel capabilities…

Molecular simulation study of dynamical properties of room temperature ionic liquids with carbon pieces

DOE PAGES

Feng, Guang; Zhao, Wei; Cummings, Peter T.; ...

2016-03-29

Room temperature ionic liquids (RTILs) with dispersed carbon pieces exhibit distinctive physiochemical properties. In order to explore the molecular mechanism, RTILs/carbon pieces mixture we investigated it by molecular dynamics (MD) simulation in this work. Rigid and flexible carbon pieces in the form of graphene with different thicknesses and carbon nanotubes in different sizes were dispersed in a representative RTIL 1-butyl-3-methyl-imidazolium dicyanamide ([Bmim][DCA]). Our study demonstrated that the diffusion coefficients of RTILs in the presence of flexible carbons are similar to those of bulk RTILs at varying temperatures, which is in contrast to the decreased diffusion of RTILs in the presencemore » of rigid carbons. In addition, interfacial ion number density at rigid carbon surfaces was higher than that at flexible ones, which is correlated with the accessible external surface area of carbon pieces. The life time of cation-anion pair in the presence of carbon pieces also exhibited a dependence on carbon flexibility. RTILs with dispersed rigid carbon pieces showed longer ion pair life time than those with flexible ones, in consistence with the observation in diffusion coefficients. Furthermore, this work highlights the necessity of including the carbon flexibility when performing MD simulation of RTILs in the presence of dispersed carbon pieces in order to obtain the reliable dynamical and interfacial structural properties.« less

Coloring the FITS Universe

NASA Astrophysics Data System (ADS)

Levay, Z. G.

2004-12-01

A new, freely-available accessory for Adobe's widely-used Photoshop image editing software makes it much more convenient to produce presentable images directly from FITS data. It merges a fully-functional FITS reader with an intuitive user interface and includes fully interactive flexibility in scaling data. Techniques for producing attractive images from astronomy data using the FITS plugin will be presented, including the assembly of full-color images. These techniques have been successfully applied to producing colorful images for public outreach with data from the Hubble Space Telescope and other major observatories. Now it is much less cumbersome for students or anyone not experienced with specialized astronomical analysis software, but reasonably familiar with digital photography, to produce useful and attractive images.

Development of Flexible Multilayer Circuits and Cables

NASA Technical Reports Server (NTRS)

Barnes, Kevin N.; Bryant, Robert; Holloway, Nancy; Draughon, Fred

2005-01-01

A continuing program addresses the development of flexible multilayer electronic circuits and associated flexible cables. This development is undertaken to help satisfy aerospace-system-engineering requirements for efficient, lightweight electrical and electronic subsystems that can fit within confined spaces, adhere to complexly shaped surfaces, and can be embedded within composite materials. Heretofore, substrate layers for commercial flexible circuitry have been made from sheets of Kapton (or equivalent) polyimide and have been bonded to copper conductors and to other substrate layers by means of adhesives. The substrates for the present developmental flexible circuitry are made from thin films of a polyimide known as LaRC(TM)-SI. This polyimide is thermoplastic and, therefore, offers the potential to eliminate delamination and the need for adhesives. The development work undertaken thus far includes experiments in the use of several techniques of design and fabrication (including computer-aided design and fabrication) of representative flexible circuits. Anticipated future efforts would focus on multilayer bonding, fabrication of prototypes, and overcoming limitations.

American College of Sports Medicine Position Stand. The recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness, and flexibility in healthy adults.

PubMed

1998-06-01

ACSM Position Stand on The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Adults. Med. Sci. Sports Exerc., Vol. 30, No. 6, pp. 975-991, 1998. The combination of frequency, intensity, and duration of chronic exercise has been found to be effective for producing a training effect. The interaction of these factors provide the overload stimulus. In general, the lower the stimulus the lower the training effect, and the greater the stimulus the greater the effect. As a result of specificity of training and the need for maintaining muscular strength and endurance, and flexibility of the major muscle groups, a well-rounded training program including aerobic and resistance training, and flexibility exercises is recommended. Although age in itself is not a limiting factor to exercise training, a more gradual approach in applying the prescription at older ages seems prudent. It has also been shown that aerobic endurance training of fewer than 2 d.wk-1, at less than 40-50% of VO2R, and for less than 10 min-1 is generally not a sufficient stimulus for developing and maintaining fitness in healthy adults. Even so, many health benefits from physical activity can be achieved at lower intensities of exercise if frequency and duration of training are increased appropriately. In this regard, physical activity can be accumulated through the day in shorter bouts of 10-min durations. In the interpretation of this position stand, it must be recognized that the recommendations should be used in the context of participant's needs, goals, and initial abilities. In this regard, a sliding scale as to the amount of time allotted and intensity of effort should be carefully gauged for the cardiorespiratory, muscular strength and endurance, and flexibility components of the program. An appropriate warm-up and cool-down period, which would include flexibility exercises, is also recommended. The important factor is to design a program for the individual to provide the proper amount of physical activity to attain maximal benefit at the lowest risk. Emphasis should be placed on factors that result in permanent lifestyle change and encourage a lifetime of physical activity.

Relationship of Catalysis and Active Site Loop Dynamics in the (βα)8-Barrel Enzyme Indole-3-glycerol Phosphate Synthase.

PubMed

Schlee, Sandra; Klein, Thomas; Schumacher, Magdalena; Nazet, Julian; Merkl, Rainer; Steinhoff, Heinz-Jürgen; Sterner, Reinhard

2018-03-08

It is important to understand how the catalytic activity of enzymes is related to their conformational flexibility. We have studied this activity-flexibility correlation using the example of indole-3-glycerol phosphate synthase from Sulfolobus solfataricus (ssIGPS), which catalyzes the fifth step in the biosynthesis of tryptophan. ssIGPS is a thermostable representative of enzymes with the frequently encountered and catalytically versatile (βα) 8 -barrel fold. Four variants of ssIGPS with increased catalytic turnover numbers were analyzed by transient kinetics at 25 °C, and wild-type ssIGPS was likewise analyzed both at 25 °C and at 60 °C. Global fitting with a minimal three-step model provided the individual rate constants for substrate binding, chemical transformation, and product release. The results showed that in both cases, namely, the application of activating mutations and temperature increase, the net increase in the catalytic turnover number is afforded by acceleration of the product release rate relative to the chemical transformation steps. Measurements of the solvent viscosity effect at 25 °C versus 60 °C confirmed this change in the rate-determining step with temperature, which is in accordance with a kink in the Arrhenius diagram of ssIGPS at ∼40 °C. When rotational diffusion rates of electron paramagnetic spin-labels attached to active site loop β1α1 are plotted in the form of an Arrhenius diagram, kinks are observed at the same temperature. These findings, together with molecular dynamics simulations, demonstrate that a different degree of loop mobility correlates with different rate-limiting steps in the catalytic mechanism of ssIGPS.

Distributed Energy Systems Integration and Demand Optimization for Autonomous Operations and Electric Grid Transactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghatikar, Girish; Mashayekh, Salman; Stadler, Michael

Distributed power systems in the U.S. and globally are evolving to provide reliable and clean energy to consumers. In California, existing regulations require significant increases in renewable generation, as well as identification of customer-side distributed energy resources (DER) controls, communication technologies, and standards for interconnection with the electric grid systems. As DER deployment expands, customer-side DER control and optimization will be critical for system flexibility and demand response (DR) participation, which improves the economic viability of DER systems. Current DER systems integration and communication challenges include leveraging the existing DER and DR technology and systems infrastructure, and enabling optimized cost,more » energy and carbon choices for customers to deploy interoperable grid transactions and renewable energy systems at scale. Our paper presents a cost-effective solution to these challenges by exploring communication technologies and information models for DER system integration and interoperability. This system uses open standards and optimization models for resource planning based on dynamic-pricing notifications and autonomous operations within various domains of the smart grid energy system. It identifies architectures and customer engagement strategies in dynamic DR pricing transactions to generate feedback information models for load flexibility, load profiles, and participation schedules. The models are tested at a real site in California—Fort Hunter Liggett (FHL). Furthermore, our results for FHL show that the model fits within the existing and new DR business models and networked systems for transactive energy concepts. Integrated energy systems, communication networks, and modeling tools that coordinate supply-side networks and DER will enable electric grid system operators to use DER for grid transactions in an integrated system.« less

3D-QSAR and docking studies on 4-anilinoquinazoline and 4-anilinoquinoline epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors

NASA Astrophysics Data System (ADS)

Assefa, Haregewein; Kamath, Shantaram; Buolamwini, John K.

2003-08-01

The overexpression and/or mutation of the epidermal growth factor receptor (EGFR) tyrosine kinase has been observed in many human solid tumors, and is under intense investigation as a novel anticancer molecular target. Comparative 3D-QSAR analyses using different alignments were undertaken employing comparative molecular field analysis (CoMFA) and comparative molecular similarity analysis (CoMSIA) for 122 anilinoquinazoline and 50 anilinoquinoline inhibitors of EGFR kinase. The SYBYL multifit alignment rule was applied to three different conformational templates, two obtained from a MacroModel Monte Carlo conformational search, and one from the bound conformation of erlotinib in complex with EGFR in the X-ray crystal structure. In addition, a flexible ligand docking alignment obtained with the GOLD docking program, and a novel flexible receptor-guided consensus dynamics alignment obtained with the DISCOVER program in the INSIGHTII modeling package were also investigated. 3D-QSAR models with q2 values up to 0.70 and r2 values up to 0.97 were obtained. Among the 4-anilinoquinazoline set, the q2 values were similar, but the ability of the different conformational models to predict the activities of an external test set varied considerably. In this regard, the model derived using the X-ray crystallographically determined bioactive conformation of erlotinib afforded the best predictive model. Electrostatic, hydrophobic and H-bond donor descriptors contributed the most to the QSAR models of the 4-anilinoquinazolines, whereas electrostatic, hydrophobic and H-bond acceptor descriptors contributed the most to the 4-anilinoquinoline QSAR, particularly the H-bond acceptor descriptor. A novel receptor-guided consensus dynamics alignment has also been introduced for 3D-QSAR studies. This new alignment method may incorporate to some extent ligand-receptor induced fit effects into 3D-QSAR models.

Dissociable Changes of Frontal and Parietal Cortices in Inherent Functional Flexibility across the Human Life Span.

PubMed

Yin, Dazhi; Liu, Wenjing; Zeljic, Kristina; Wang, Zhiwei; Lv, Qian; Fan, Mingxia; Cheng, Wenhong; Wang, Zheng

2016-09-28

Extensive evidence suggests that frontoparietal regions can dynamically update their pattern of functional connectivity, supporting cognitive control and adaptive implementation of task demands. However, it is largely unknown whether this flexibly functional reconfiguration is intrinsic and occurs even in the absence of overt tasks. Based on recent advances in dynamics of resting-state functional resonance imaging (fMRI), we propose a probabilistic framework in which dynamic reconfiguration of intrinsic functional connectivity between each brain region and others can be represented as a probability distribution. A complexity measurement (i.e., entropy) was used to quantify functional flexibility, which characterizes heterogeneous connectivity between a particular region and others over time. Following this framework, we identified both functionally flexible and specialized regions over the human life span (112 healthy subjects from 13 to 76 years old). Across brainwide regions, we found regions showing high flexibility mainly in the higher-order association cortex, such as the lateral prefrontal cortex (LPFC), lateral parietal cortex, and lateral temporal lobules. In contrast, visual, auditory, and sensory areas exhibited low flexibility. Furthermore, we observed that flexibility of the right LPFC improved during maturation and reduced due to normal aging, with the opposite occurring for the left lateral parietal cortex. Our findings reveal dissociable changes of frontal and parietal cortices over the life span in terms of inherent functional flexibility. This study not only provides a new framework to quantify the spatiotemporal behavior of spontaneous brain activity, but also sheds light on the organizational principle behind changes in brain function across the human life span. Recent neuroscientific research has demonstrated that the human capability of adaptive task control is primarily the result of the flexible operation of frontal brain networks. However, it remains unclear whether this flexibly functional reconfiguration is intrinsic and occurs in the absence of an overt task. In this study, we propose a probabilistic framework to quantify the functional flexibility of each brain region using resting-state fMRI. We identify regions showing high flexibility mainly in the higher-order association cortex. In contrast, primary and unimodal visual and sensory areas show low flexibility. On the other hand, our findings reveal dissociable changes of frontal and parietal cortices in terms of inherent functional flexibility over the life span. Copyright © 2016 the authors 0270-6474/16/3610060-15$15.00/0.

Molecular dynamics force-field refinement against quasi-elastic neutron scattering data

DOE PAGES

Borreguero Calvo, Jose M.; Lynch, Vickie E.

2015-11-23

Quasi-elastic neutron scattering (QENS) is one of the experimental techniques of choice for probing the dynamics at length and time scales that are also in the realm of full-atom molecular dynamics (MD) simulations. This overlap enables extension of current fitting methods that use time-independent equilibrium measurements to new methods fitting against dynamics data. We present an algorithm that fits simulation-derived incoherent dynamical structure factors against QENS data probing the diffusive dynamics of the system. We showcase the difficulties inherent to this type of fitting problem, namely, the disparity between simulation and experiment environment, as well as limitations in the simulationmore » due to incomplete sampling of phase space. We discuss a methodology to overcome these difficulties and apply it to a set of full-atom MD simulations for the purpose of refining the force-field parameter governing the activation energy of methyl rotation in the octa-methyl polyhedral oligomeric silsesquioxane molecule. Our optimal simulated activation energy agrees with the experimentally derived value up to a 5% difference, well within experimental error. We believe the method will find applicability to other types of diffusive motions and other representation of the systems such as coarse-grain models where empirical fitting is essential. In addition, the refinement method can be extended to the coherent dynamic structure factor with no additional effort.« less

A map of local adaptation in Arabidopsis thaliana.

PubMed

Fournier-Level, A; Korte, A; Cooper, M D; Nordborg, M; Schmitt, J; Wilczek, A M

2011-10-07

Local adaptation is critical for species persistence in the face of rapid environmental change, but its genetic basis is not well understood. Growing the model plant Arabidopsis thaliana in field experiments in four sites across the species' native range, we identified candidate loci for local adaptation from a genome-wide association study of lifetime fitness in geographically diverse accessions. Fitness-associated loci exhibited both geographic and climatic signatures of local adaptation. Relative to genomic controls, high-fitness alleles were generally distributed closer to the site where they increased fitness, occupying specific and distinct climate spaces. Independent loci with different molecular functions contributed most strongly to fitness variation in each site. Independent local adaptation by distinct genetic mechanisms may facilitate a flexible evolutionary response to changing environment across a species range.

Physical Fitness Percentiles of German Children Aged 9–12 Years: Findings from a Longitudinal Study

PubMed Central

Golle, Kathleen; Muehlbauer, Thomas; Wick, Ditmar; Granacher, Urs

2015-01-01

Background Generating percentile values is helpful for the identification of children with specific fitness characteristics (i.e., low or high fitness level) to set appropriate fitness goals (i.e., fitness/health promotion and/or long-term youth athlete development). Thus, the aim of this longitudinal study was to assess physical fitness development in healthy children aged 9–12 years and to compute sex- and age-specific percentile values. Methods Two-hundred and forty children (88 girls, 152 boys) participated in this study and were tested for their physical fitness. Physical fitness was assessed using the 50-m sprint test (i.e., speed), the 1-kg ball push test, the triple hop test (i.e., upper- and lower- extremity muscular power), the stand-and-reach test (i.e., flexibility), the star run test (i.e., agility), and the 9-min run test (i.e., endurance). Age- and sex-specific percentile values (i.e., P10 to P90) were generated using the Lambda, Mu, and Sigma method. Adjusted (for change in body weight, height, and baseline performance) age- and sex-differences as well as the interactions thereof were expressed by calculating effect sizes (Cohen’s d). Results Significant main effects of Age were detected for all physical fitness tests (d = 0.40–1.34), whereas significant main effects of Sex were found for upper-extremity muscular power (d = 0.55), flexibility (d = 0.81), agility (d = 0.44), and endurance (d = 0.32) only. Further, significant Sex by Age interactions were observed for upper-extremity muscular power (d = 0.36), flexibility (d = 0.61), and agility (d = 0.27) in favor of girls. Both, linear and curvilinear shaped curves were found for percentile values across the fitness tests. Accelerated (curvilinear) improvements were observed for upper-extremity muscular power (boys: 10–11 yrs; girls: 9–11 yrs), agility (boys: 9–10 yrs; girls: 9–11 yrs), and endurance (boys: 9–10 yrs; girls: 9–10 yrs). Tabulated percentiles for the 9-min run test indicated that running distances between 1,407–1,507 m, 1,479–1,597 m, 1,423–1,654 m, and 1,433–1,666 m in 9- to 12-year-old boys and 1,262–1,362 m, 1,329–1,434 m, 1,392–1,501 m, and 1,415–1,526 m in 9- to 12-year-old girls correspond to a “medium” fitness level (i.e., P40 to P60) in this population. Conclusions The observed differences in physical fitness development between boys and girls illustrate that age- and sex-specific maturational processes might have an impact on the fitness status of healthy children. Our statistical analyses revealed linear (e.g., lower-extremity muscular power) and curvilinear (e.g., agility) models of fitness improvement with age which is indicative of timed and capacity-specific fitness development pattern during childhood. Lastly, the provided age- and sex-specific percentile values can be used by coaches for talent identification and by teachers for rating/grading of children’s motor performance. PMID:26544848

Quick-connect fasteners for assembling devices in space

NASA Technical Reports Server (NTRS)

Evenson, Erik E. (Inventor); Wesselski, Clarence J. (Inventor); Ruiz, Steve C. (Inventor)

1993-01-01

A quick-connect fastener of a relatively-simple straightforward design is arranged with a tubular body adapted to be engaged against an attachment fitting in coincidental alignment with an opening in that fitting. A tubular collet having flexible fingers projecting from its forward end is arranged in the fastener body to be shifted forwardly by an elongated expander member coaxially arranged within the tubular collet for advancing the collet fingers into the opening in the attachment fitting. Biasing means are arranged between the elongated expander member and a rotatable actuator which is threadedly mounted within the tubular collet so as to be rotated for urging the expander member into engagement with the collet fingers. A first coupling member is arranged on the rotatable actuator to be accessible from outside of the fastener so that a second coupling member on the distal end of a flexible shaft can be introduced into the fastener body and coupled to the first coupling member to enable a typical actuating tool coupled to the shaft outside of the fastener body to be operated for advancing the outwardly-enlarged ends of the collet fingers into the opening in the attachment fitting and thereafter rotating the actuator member to expand the fingers within the opening for releasably latching the fastener to that attachment fitting. Upon expansion of the collet fingers, the biasing means impose a biasing force on the expander to releasably retain the fingers in their latching positions.

IMFIT: A FAST, FLEXIBLE NEW PROGRAM FOR ASTRONOMICAL IMAGE FITTING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erwin, Peter; Universitäts-Sternwarte München, Scheinerstrasse 1, D-81679 München

2015-02-01

I describe a new, open-source astronomical image-fitting program called IMFIT, specialized for galaxies but potentially useful for other sources, which is fast, flexible, and highly extensible. A key characteristic of the program is an object-oriented design that allows new types of image components (two-dimensional surface-brightness functions) to be easily written and added to the program. Image functions provided with IMFIT include the usual suspects for galaxy decompositions (Sérsic, exponential, Gaussian), along with Core-Sérsic and broken-exponential profiles, elliptical rings, and three components that perform line-of-sight integration through three-dimensional luminosity-density models of disks and rings seen at arbitrary inclinations. Available minimization algorithmsmore » include Levenberg-Marquardt, Nelder-Mead simplex, and Differential Evolution, allowing trade-offs between speed and decreased sensitivity to local minima in the fit landscape. Minimization can be done using the standard χ{sup 2} statistic (using either data or model values to estimate per-pixel Gaussian errors, or else user-supplied error images) or Poisson-based maximum-likelihood statistics; the latter approach is particularly appropriate for cases of Poisson data in the low-count regime. I show that fitting low-signal-to-noise ratio galaxy images using χ{sup 2} minimization and individual-pixel Gaussian uncertainties can lead to significant biases in fitted parameter values, which are avoided if a Poisson-based statistic is used; this is true even when Gaussian read noise is present.« less

Cardiovascular program to improve physical fitness in those over 60 years old – pilot study

PubMed Central

Castillo-Rodríguez, Alfonso; Chinchilla-Minguet, José Luis

2014-01-01

Background In Spain, more than 50% of 60-year-olds are obese. Obesity is a disease with serious cardiovascular risks. The mortality rate for cardiovascular disease in Spain is 31.1%. Objectives To improve aerobic fitness, strength, flexibility and balance, and body composition (BC) in persons over 60 years old. Materials and methods A clinical intervention study of 24 participants was carried out over a period of 3 months. Aerobic fitness was assessed using the Rockport 1-Mile Walk Test. Upper-body strength was evaluated with an ad hoc test. Flexibility and balance were evaluated using the Sit and Reach Test and the Stork Balance Stand Test, respectively. Anthropometric measurements were taken by bioelectrical impedance. Results After 3 months of training, aerobic fitness was improved, as demonstrated by improved test times (pretest 13.04 minutes, posttest 12.13 minutes; P<0.05). Body composition was also improved, but the results were not statistically significant (fat mass pretest 31.58%±5.65%, posttest 30.65%±6.31%; skeletal muscle mass pretest 43.99±9.53 kg, posttest 46.63±10.90 kg). Conclusion Our data show that in subjects over 60 years old, aerobic fitness was improved due to program intervention. However, these results should be treated with caution, because of the limited sample size and the brief time period of this pilot study. A more rigorous study would include a sample of at least 100 participants. PMID:25143714

Dynamics of flexible fibers transported in confined viscous flows

NASA Astrophysics Data System (ADS)

Cappello, Jean; Duprat, Camille; Du Roure, Olivia; Nagel, Mathias; Gallaire, François; Lindner, Anke

2017-11-01

The dynamics of elongated objects has been extensively studied in unbounded media as for example the sedimentation of fibers at low Reynolds numbers. It has recently been shown that these transport dynamics are strongly modified by bounding walls. Here we focus on the dynamics of flexible fibers confined by the top and bottom walls of a microchannel and transported in pressure-driven flows. We combine well-controlled microfluidic experiments and simulations using modified Brinkmann equations. We control shape, orientation, and mechanical properties of our fibers using micro-fabrication techniques and in-situ characterization methods. These elastic fibers can be deformed by viscous and pressure forces leading to very rich transport dynamics coupling lateral drift with shape evolution. We show that the bending of a perpendicular fiber is proportional to an elasto-viscous number and we fully characterize the influence of the confinement on the deformation of the fiber. Experiments on parallel flexible fibers reveal the existence of a buckling threshold. The European Research Council is acknowledged for funding the work through a consolidator Grant (ERC PaDyFlow 682367).

Atomic modeling of cryo-electron microscopy reconstructions--joint refinement of model and imaging parameters.

PubMed

Chapman, Michael S; Trzynka, Andrew; Chapman, Brynmor K

2013-04-01

When refining the fit of component atomic structures into electron microscopic reconstructions, use of a resolution-dependent atomic density function makes it possible to jointly optimize the atomic model and imaging parameters of the microscope. Atomic density is calculated by one-dimensional Fourier transform of atomic form factors convoluted with a microscope envelope correction and a low-pass filter, allowing refinement of imaging parameters such as resolution, by optimizing the agreement of calculated and experimental maps. A similar approach allows refinement of atomic displacement parameters, providing indications of molecular flexibility even at low resolution. A modest improvement in atomic coordinates is possible following optimization of these additional parameters. Methods have been implemented in a Python program that can be used in stand-alone mode for rigid-group refinement, or embedded in other optimizers for flexible refinement with stereochemical restraints. The approach is demonstrated with refinements of virus and chaperonin structures at resolutions of 9 through 4.5 Å, representing regimes where rigid-group and fully flexible parameterizations are appropriate. Through comparisons to known crystal structures, flexible fitting by RSRef is shown to be an improvement relative to other methods and to generate models with all-atom rms accuracies of 1.5-2.5 Å at resolutions of 4.5-6 Å. Copyright © 2013 Elsevier Inc. All rights reserved.

Cardiovascular exercise training extends influenza vaccine seroprotection in sedentary older adults: the immune function intervention trial.

PubMed

Woods, Jeffrey A; Keylock, K Todd; Lowder, Thomas; Vieira, Victoria J; Zelkovich, William; Dumich, Sara; Colantuano, Kim; Lyons, Kristin; Leifheit, Kurt; Cook, Marc; Chapman-Novakofski, Karen; McAuley, Edward

2009-12-01

To determine whether cardiovascular exercise training resulted in improved antibody responses to influenza vaccination in sedentary elderly people who exhibited poor vaccine responses. Single-site randomized parallel-arm 10-month controlled trial. University of Illinois at Urbana-Champaign. One hundred forty-four sedentary, healthy older (69.9 +/- 0.4) adults. Moderate (60-70% maximal oxygen uptake) cardiovascular exercise was compared with flexibility and balance training. The primary outcome was influenza vaccine response, as measured according to hemagglutination inhibition (HI) anti-influenza antibody titer and seroprotective responses (HI titer > or =40). Secondary measures included cardiovascular fitness and body composition. Of the 160 participants enrolled, 144 (90%) completed the 10-month intervention with excellent compliance ( approximately 83%). Cardiovascular, but not flexibility, exercise intervention resulted in improvements in indices of cardiovascular fitness, including maximal oxygen uptake. Although not affecting peak (e.g., 3 and 6 weeks) postvaccine anti-influenza HI titers, cardiovascular exercise resulted in a significant increase in seroprotection 24 weeks after vaccination (30-100% dependent on vaccine variant), whereas flexibility training did not. Participants randomized to cardiovascular exercise experienced improvements in influenza seroprotection throughout the entire influenza season, whereas those in the balance and flexibility intervention did not. Although there were no differences in reported respiratory tract infections, the exercise group exhibited reduced overall illness severity and sleep disturbance. These data support the hypothesis that regular endurance exercise improves influenza vaccine responses.

Control of complex components with Smart Flexible Phased Arrays.

PubMed

Casula, O; Poidevin, C; Cattiaux, G; Dumas, Ph

2006-12-22

The inspection is mainly performed in contact with ultrasonic wedge transducers; However, the shape cannot fit the changing geometries of components (butt weld, nozzle, elbow). The variable thickness of the coupling layer, between the wedge and the local surface, leads to beam distortions and losses of sensitivity. Previous studies have shown that these two phenomena contribute to reduce the inspection performances leading to shadow area, split beam.... Flexible phased arrays have been developed to fit the complex profile and improve such controls. The radiating surface is composed with independent piezoelectric elements mechanically assembled and a profilometer, embedded in the transducer, measures the local distortion. The computed shape is used by an algorithm to compute in real-time the adapted delay laws compensating the distortions of 2D or 3D profiles. Those delay laws are transferred to the real-time UT acquisition system, which applies them to the piezoelectric elements. This self-adaptive process preserves, during the scanning, the features of the focused beam (orientation and focal depth) in the specimen. To validate the concept of the Smart Flexible Phased Array Transducer, prototypes have been integrated to detect flaws machined in mock-ups with realistic irregular 2D and 3D shapes. Inspections have been carried out on samples showing the enhancement performances of the "Smart Flexible Phased Array" and validating the mechanical and acoustical behaviors of these probes.

Computational Methods for Structural Mechanics and Dynamics

NASA Technical Reports Server (NTRS)

Stroud, W. Jefferson (Editor); Housner, Jerrold M. (Editor); Tanner, John A. (Editor); Hayduk, Robert J. (Editor)

1989-01-01

Topics addressed include: transient dynamics; transient finite element method; transient analysis in impact and crash dynamic studies; multibody computer codes; dynamic analysis of space structures; multibody mechanics and manipulators; spatial and coplanar linkage systems; flexible body simulation; multibody dynamics; dynamical systems; and nonlinear characteristics of joints.

Coupled Vortex-Lattice Flight Dynamic Model with Aeroelastic Finite-Element Model of Flexible Wing Transport Aircraft with Variable Camber Continuous Trailing Edge Flap for Drag Reduction

NASA Technical Reports Server (NTRS)

Nguyen, Nhan; Ting, Eric; Nguyen, Daniel; Dao, Tung; Trinh, Khanh

2013-01-01

This paper presents a coupled vortex-lattice flight dynamic model with an aeroelastic finite-element model to predict dynamic characteristics of a flexible wing transport aircraft. The aircraft model is based on NASA Generic Transport Model (GTM) with representative mass and stiffness properties to achieve a wing tip deflection about twice that of a conventional transport aircraft (10% versus 5%). This flexible wing transport aircraft is referred to as an Elastically Shaped Aircraft Concept (ESAC) which is equipped with a Variable Camber Continuous Trailing Edge Flap (VCCTEF) system for active wing shaping control for drag reduction. A vortex-lattice aerodynamic model of the ESAC is developed and is coupled with an aeroelastic finite-element model via an automated geometry modeler. This coupled model is used to compute static and dynamic aeroelastic solutions. The deflection information from the finite-element model and the vortex-lattice model is used to compute unsteady contributions to the aerodynamic force and moment coefficients. A coupled aeroelastic-longitudinal flight dynamic model is developed by coupling the finite-element model with the rigid-body flight dynamic model of the GTM.

Dynamic analysis of space structures including elastic, multibody, and control behavior

NASA Technical Reports Server (NTRS)

Pinson, Larry; Soosaar, Keto

1989-01-01

The problem is to develop analysis methods, modeling stategies, and simulation tools to predict with assurance the on-orbit performance and integrity of large complex space structures that cannot be verified on the ground. The problem must incorporate large reliable structural models, multi-body flexible dynamics, multi-tier controller interaction, environmental models including 1g and atmosphere, various on-board disturbances, and linkage to mission-level performance codes. All areas are in serious need of work, but the weakest link is multi-body flexible dynamics.

VizieR Online Data Catalog: High spatial resolution observations of HM Sge (Sacuto+, 2009)

NASA Astrophysics Data System (ADS)

Sacuto, S.; Chesneau, O.

2008-11-01

All the data products are stored in the FITS-based, optical interferometry data exchange format (OI-FITS), described in Pauls et al. (2005PASP..117.1255P). The OI Exchange Format is a standard for exchanging calibrated data from optical (visible/infrared) stellar interferometers. The standard is based on the Flexible Image Transport System (FITS), and supports storage of the optical interferometric observations including visibilities and differential phases. Several routines to read and write this format in various languages can be found in: Webpage http://www.mrao.cam.ac.uk/~jsy1001/exchange (2 data files).

VizieR Online Data Catalog: High spatial resolution observations of HM Sge (Sacuto+, 2007)

NASA Astrophysics Data System (ADS)

Sacuto, S.; Chesneau, O.; Vannier, M.; Cruzalebes, P.

2007-01-01

All the data products are stored in the FITS-based, optical interferometry data exchange format (OI-FITS), described in Pauls et al. (2005PASP..117.1255P). The OI Exchange Format is a standard for exchanging calibrated data from optical (visible/infrared) stellar interferometers. The standard is based on the Flexible Image Transport System (FITS), and supports storage of the optical interferometric observations including visibilities and differential phases. Several routines to read and write this format in various languages can be found in: Webpage http://www.mrao.cam.ac.uk/~jsy1001/exchange (1 data file).

What Physical Fitness Component Is Most Closely Associated With Adolescents' Blood Pressure?

PubMed

Nunes, Heloyse E G; Alves, Carlos A S; Gonçalves, Eliane C A; Silva, Diego A S

2017-12-01

This study aimed to determine which of four selected physical fitness variables, would be most associated with blood pressure changes (systolic and diastolic) in a large sample of adolescents. This was a descriptive and cross-sectional, epidemiological study of 1,117 adolescents aged 14-19 years from southern Brazil. Systolic and diastolic blood pressure were measured by a digital pressure device, and the selected physical fitness variables were body composition (body mass index), flexibility (sit-and-reach test), muscle strength/resistance (manual dynamometer), and aerobic fitness (Modified Canadian Aerobic Fitness Test). Simple and multiple linear regression analyses revealed that aerobic fitness and muscle strength/resistance best explained variations in systolic blood pressure for boys (17.3% and 7.4% of variance) and girls (7.4% of variance). Aerobic fitness, body composition, and muscle strength/resistance are all important indicators of blood pressure control, but aerobic fitness was a stronger predictor of systolic blood pressure in boys and of diastolic blood pressure in both sexes.

Punctuated equilibrium and shock waves in molecular models of biological evolution.

PubMed

Saakian, David B; Ghazaryan, Makar H; Hu, Chin-Kun

2014-08-01

We consider the dynamics in infinite population evolution models with a general symmetric fitness landscape. We find shock waves, i.e., discontinuous transitions in the mean fitness, in evolution dynamics even with smooth fitness landscapes, which means that the search for the optimal evolution trajectory is more complicated. These shock waves appear in the case of positive epistasis and can be used to represent punctuated equilibria in biological evolution during long geological time scales. We find exact analytical solutions for discontinuous dynamics at the large-genome-length limit and derive optimal mutation rates for a fixed fitness landscape to send the population from the initial configuration to some final configuration in the fastest way.

The flexibility and dynamics of protein disulfide isomerase

PubMed Central

Wells, Stephen A.; Emilio Jimenez‐Roldan, J.; Bhattacharyya, Moitrayee; Vishweshwara, Saraswathi; Freedman, Robert B.

2016-01-01

ABSTRACT We have studied the mobility of the multidomain folding catalyst, protein disulfide isomerase (PDI), by a coarse‐graining approach based on flexibility. We analyze our simulations of yeast PDI (yPDI) using measures of backbone movement, relative positions and orientations of domains, and distances between functional sites. We find that there is interdomain flexibility at every interdomain junction but these show very different characteristics. The extent of interdomain flexibility is such that yPDI's two active sites can approach much more closely than is found in crystal structures—and indeed hinge motion to bring these sites into proximity is the lowest energy normal mode of motion of the protein. The flexibility predicted for yPDI (based on one structure) includes the other known conformation of yPDI and is consistent with (i) the mobility observed experimentally for mammalian PDI and (ii) molecular dynamics. We also observe intradomain flexibility and clear differences between the domains in their propensity for internal motion. Our results suggest that PDI flexibility enables it to interact with many different partner molecules of widely different sizes and shapes, and highlights considerable similarities of yPDI and mammalian PDI. Proteins 2016; 84:1776–1785. © 2016 Wiley Periodicals, Inc. PMID:27616289

High frequency flow-structural interaction in dense subsonic fluids

NASA Technical Reports Server (NTRS)

Liu, Baw-Lin; Ofarrell, J. M.

1995-01-01

Prediction of the detailed dynamic behavior in rocket propellant feed systems and engines and other such high-energy fluid systems requires precise analysis to assure structural performance. Designs sometimes require placement of bluff bodies in a flow passage. Additionally, there are flexibilities in ducts, liners, and piping systems. A design handbook and interactive data base have been developed for assessing flow/structural interactions to be used as a tool in design and development, to evaluate applicable geometries before problems develop, or to eliminate or minimize problems with existing hardware. This is a compilation of analytical/empirical data and techniques to evaluate detailed dynamic characteristics of both the fluid and structures. These techniques have direct applicability to rocket engine internal flow passages, hot gas drive systems, and vehicle propellant feed systems. Organization of the handbook is by basic geometries for estimating Strouhal numbers, added mass effects, mode shapes for various end constraints, critical onset flow conditions, and possible structural response amplitudes. Emphasis is on dense fluids and high structural loading potential for fatigue at low subsonic flow speeds where high-frequency excitations are possible. Avoidance and corrective measure illustrations are presented together with analytical curve fits for predictions compiled from a comprehensive data base.

Evolution in action: climate change, biodiversity dynamics and emerging infectious disease

PubMed Central

Hoberg, Eric P.; Brooks, Daniel R.

2015-01-01

Climatological variation and ecological perturbation have been pervasive drivers of faunal assembly, structure and diversification for parasites and pathogens through recurrent events of geographical and host colonization at varying spatial and temporal scales of Earth history. Episodic shifts in climate and environmental settings, in conjunction with ecological mechanisms and host switching, are often critical determinants of parasite diversification, a view counter to more than a century of coevolutionary thinking about the nature of complex host–parasite assemblages. Parasites are resource specialists with restricted host ranges, yet shifts onto relatively unrelated hosts are common during phylogenetic diversification of parasite lineages and directly observable in real time. The emerging Stockholm Paradigm resolves this paradox: Ecological Fitting (EF)—phenotypic flexibility and phylogenetic conservatism in traits related to resource use, most notably host preference—provides many opportunities for rapid host switching in changing environments, without the evolution of novel host-utilization capabilities. Host shifts via EF fuel the expansion phase of the Oscillation Hypothesis of host range and speciation and, more generally, the generation of novel combinations of interacting species within the Geographic Mosaic Theory of Coevolution. In synergy, an environmental dynamic of Taxon Pulses establishes an episodic context for host and geographical colonization. PMID:25688014

Quantitative phase imaging of cell division in yeast cells and E.coli using digital holographic microscopy

NASA Astrophysics Data System (ADS)

Pandiyan, Vimal Prabhu; John, Renu

2015-12-01

Digital holographic microscope (DHM) is an emerging quantitative phase imaging technique with unique imaging scales and resolutions leading to multitude of applications. DHM is promising as a novel investigational and applied tool for cell imaging, studying the morphology and real time dynamics of cells and a number of related applications. The use of numerical propagation and computational digital optics offer unique flexibility to tune the depth of focus, and compensate for image aberrations. In this work, we report imaging the dynamics of cell division in E.coli and yeast cells using a DHM platform. We demonstrate 3-D and depth imaging as well as reconstruction of phase profiles of E.coli and yeast cells using the system. We record a digital hologram of E.coli and yeast cells and reconstruct the image using Fresnel propagation algorithm. We also use aberration compensation algorithms for correcting the aberrations that are introduced by the microscope objective in the object path using linear least square fitting techniques. This work demonstrates the strong potential of a DHM platform in 3-D live cell imaging, fast clinical quantifications and pathological applications.

Non-Linear Structural Dynamics Characterization using a Scanning Laser Vibrometer

NASA Technical Reports Server (NTRS)

Pai, P. F.; Lee, S.-Y.

2003-01-01

This paper presents the use of a scanning laser vibrometer and a signal decomposition method to characterize non-linear dynamics of highly flexible structures. A Polytec PI PSV-200 scanning laser vibrometer is used to measure transverse velocities of points on a structure subjected to a harmonic excitation. Velocity profiles at different times are constructed using the measured velocities, and then each velocity profile is decomposed using the first four linear mode shapes and a least-squares curve-fitting method. From the variations of the obtained modal \\ielocities with time we search for possible non-linear phenomena. A cantilevered titanium alloy beam subjected to harmonic base-excitations around the second. third, and fourth natural frequencies are examined in detail. Influences of the fixture mass. gravity. mass centers of mode shapes. and non-linearities are evaluated. Geometrically exact equations governing the planar, harmonic large-amplitude vibrations of beams are solved for operational deflection shapes using the multiple shooting method. Experimental results show the existence of 1:3 and 1:2:3 external and internal resonances. energy transfer from high-frequency modes to the first mode. and amplitude- and phase- modulation among several modes. Moreover, the existence of non-linear normal modes is found to be questionable.

Using gamma distribution to determine half-life of rotenone, applied in freshwater.

PubMed

Rohan, Maheswaran; Fairweather, Alastair; Grainger, Natasha

2015-09-15

Following the use of rotenone to eradicate invasive pest fish, a dynamic first-order kinetic model is usually used to determine the half-life and rate at which rotenone dissipated from the treated waterbody. In this study, we investigate the use of a stochastic gamma model for determining the half-life and rate at which rotenone dissipates from waterbodies. The first-order kinetic and gamma models produced similar values for the half-life (4.45 days and 5.33 days respectively) and days to complete dissipation (51.2 days and 52.48 days respectively). However, the gamma model fitted the data better and was more flexible than the first-order kinetic model, allowing us to use covariates and to predict a possible range for the half-life of rotenone. These benefits are particularly important when examining the influence that different environmental factors have on rotenone dissipation and when trying to predict the rate at which rotenone will dissipate during future operations. We therefore recommend that in future the gamma distribution model is used when calculating the half-life of rotenone in preference to the dynamic first-order kinetics model. Copyright © 2015 Elsevier B.V. All rights reserved.

Combat Fitness a Concept Vital to National Defense

DTIC Science & Technology

2010-06-18

Physical fitness testing has traditionally been focused on a 1.5- to 3-mile run, push-ups, sit-ups, and, in some Services pull -ups, flexibility, and...Performance 6 Shoot Physical Requirements Employ hand grenades Run under load, jump, bound, high/low crawl, climb, push, pull , squat, lunge, roll...jump, bound, high/low crawl, climb, push, pull , squat, lunge, roll, stop, start, change direction and get up/down. Navigate from one point to

Estimating Dynamical Systems: Derivative Estimation Hints from Sir Ronald A. Fisher

ERIC Educational Resources Information Center

Deboeck, Pascal R.

2010-01-01

The fitting of dynamical systems to psychological data offers the promise of addressing new and innovative questions about how people change over time. One method of fitting dynamical systems is to estimate the derivatives of a time series and then examine the relationships between derivatives using a differential equation model. One common…

Dynamics and control of flexible spacecraft during and after slewing maneuvers

NASA Technical Reports Server (NTRS)

Kakad, Yogendra P.

1989-01-01

The dynamics and control of slewing maneuvers of NASA Spacecraft COntrol Laboratory Experiment (SCOLE) are analyzed. The control problem of slewing maneuvers of SCOLE is formulated in terms of an arbitrary maneuver about any given axis. The control system is developed for the combined problem of rigid-body slew maneuver and vibration suppression of the flexible appendage. The control problem formulation incorporates the nonlinear dynamical equations derived previously, and is expressed in terms of a two-point boundary value problem utilizing a quadratic type of performance index. The two-point boundary value problem is solved as a hierarchical control problem with the overall system being split in terms of two subsystems, namely the slewing of the entire assembly and the vibration suppression of the flexible antenna. The coupling variables between the two dynamical subsystems are identified and these two subsystems for control purposes are treated independently in parallel at the first level. Then the state-space trajectory of the combined problem is optimized at the second level.

Test of a flexible spacecraft dynamics simulator

NASA Technical Reports Server (NTRS)

Dichmann, Donald; Sedlak, Joseph

1998-01-01

There are a number of approaches one can take to modeling the dynamics of a flexible body. While one can attempt to capture the full dynamical behavior subject to disturbances from actuators and environmental torques, such a detailed description often is unnecessary. Simplification is possible either by limiting the amplitude of motion to permit linearization of the dynamics equations or by restricting the types of allowed motion. In this work, we study the nonlinear dynamics of bending deformations of wire booms on spinning spacecraft. The theory allows for large amplitude excursions from equilibrium while enforcing constraints on the dynamics to prohibit those modes that are physically less relevant or are expected to damp out fast. These constraints explicitly remove the acoustic modes (i.e., longitudinal sound waves and shear waves) while allowing for arbitrary bending and twisting, motions which typically are of lower frequency. As a test case, a spin axis reorientation maneuver by the Polar Plasma Laboratory (POLAR) spacecraft has been simulated. POLAR was chosen as a representative spacecraft because it has flexible wire antennas that extend to a length of 65 meters. Bending deformations in these antennas could be quite large and have a significant effect on the attitude dynamics of the spacecraft body. Summary results from the simulation are presented along, with a comparison with POLAR flight data.

The cervical cap (image)

MedlinePlus

The cervical cap is a flexible rubber cup-like device that is filled with spermicide and self-inserted over the cervix ... left in place several hours after intercourse. The cap is a prescribed device fitted by a health ...

Ceramic tamper-revealing seals

DOEpatents

Kupperman, David S.; Raptis, Apostolos C.; Sheen, Shuh-Haw

1992-01-01

A flexible metal or ceramic cable with composite ceramic ends, or a u-shaped ceramic connecting element attached to a binding element plate or block cast from alumina or zirconium, and connected to the connecting element by shrink fitting.

Physical Activity Might Be of Greater Importance for Good Spinal Control Than If You Have Had Pain or Not: A Longitudinal Study.

PubMed

Aasa, Ulrika; Lundell, Sara; Aasa, Björn; Westerståhl, Maria

2015-12-01

Longitudinal design. A cohort followed in 3 waves of data collection. The aim of the study was to describe the relationships between the performance of 2 tests of spinal control at the age of 52 years and low back pain, physical activity level, and fitness earlier in life, as well as to describe the cross-sectional relationships between these measures. Altered spinal control has been linked to pain; however, other stimuli may also lead to inability to control the movements of the spine. Participants answered questions about physical activity and low back pain, and performed physical fitness tests at the age of 16, 34, and 52 years. The fitness test battery included tests of endurance in the back and abdominal muscles, a submaximal bicycle ergometer test to estimate maximal oxygen uptake, and measurements of hip flexion, thoracic spine flexibility, and anthropometrics. Two tests were aggregated to a physical fitness index. At the age of 52, also 2 tests of spinal control, the standing Waiter's bow (WB) and the supine double leg lower (LL) were performed. Logistic regression analyses showed that higher back muscle endurance at the age of 34 years could positively predict WB performance at 52 years and higher physical fitness at the age of 34 could positively predict LL performance at 52 years. Regarding cross-sectional relationships, an inability to perform the WB correctly was associated with lower physical fitness, flexibility and physical activity, and larger waist circumference. An inability to correctly perform the LL was associated with lower physical fitness. One-year prevalence of pain was not significantly associated with WB or LL test performance. An active life resulting in higher physical fitness is related to better spinal control in middle-aged men and women. This further strengthens the importance of physical activity throughout the life span. 3.

Eight weeks of a combination of high intensity interval training and conventional training reduce visceral adiposity and improve physical fitness: a group-based intervention.

PubMed

Giannaki, Christoforos D; Aphamis, George; Sakkis, Panikos; Hadjicharalambous, Marios

2016-04-01

High intensity interval training (HIIT) has been recently promoted as an effective, low volume and time-efficient training method for improving fitness and health related parameters. The aim of the current study was to examine the effect of a combination of a group-based HIIT and conventional gym training on physical fitness and body composition parameters in healthy adults. Thirty nine healthy adults volunteered to participate in this eight-week intervention study. Twenty three participants performed regular gym training 4 days a week (C group), whereas the remaining 16 participants engaged twice a week in HIIT and twice in regular gym training (HIIT-C group) as the other group. Total body fat and visceral adiposity levels were calculated using bioelectrical impedance analysis. Physical fitness parameters such as cardiorespiratory fitness, speed, lower limb explosiveness, flexibility and isometric arm strength were assessed through a battery of field tests. Both exercise programs were effective in reducing total body fat and visceral adiposity (P<0.05) and improving handgrip strength, sprint time, jumping ability and flexibility (P<0.05) whilst only the combination of HIIT and conventional training improved cardiorespiratory fitness levels (P<0.05). A between of group changes analysis revealed that HIIT-C resulted in significantly greater reduction in both abdominal girth and visceral adiposity compared with conventional training (P<0.05). Eight weeks of combined group-based HIIT and conventional training improve various physical fitness parameters and reduce both total and visceral fat levels. This type of training was also found to be superior compared with conventional exercise training alone in terms of reducing more visceral adiposity levels. Group-based HIIT may consider as a good methods for individuals who exercise in gyms and craving to acquire significant fitness benefits in relatively short period of time.

Gain in computational efficiency by vectorization in the dynamic simulation of multi-body systems

NASA Technical Reports Server (NTRS)

Amirouche, F. M. L.; Shareef, N. H.

1991-01-01

An improved technique for the identification and extraction of the exact quantities associated with the degrees of freedom at the element as well as the flexible body level is presented. It is implemented in the dynamic equations of motions based on the recursive formulation of Kane et al. (1987) and presented in a matrix form, integrating the concepts of strain energy, the finite-element approach, modal analysis, and reduction of equations. This technique eliminates the CPU intensive matrix multiplication operations in the code's hot spots for the dynamic simulation of the interconnected rigid and flexible bodies. A study of a simple robot with flexible links is presented by comparing the execution times on a scalar machine and a vector-processor with and without vector options. Performance figures demonstrating the substantial gains achieved by the technique are plotted.

The role of proline substitutions within flexible regions on thermostability of luciferase.

PubMed

Yu, Haoran; Zhao, Yang; Guo, Chao; Gan, Yiru; Huang, He

2015-01-01

Improving the stability of firefly luciferase has been a critical issue for its wider industrial applications. Studies about hyperthermophile proteins show that flexibility could be an effective indicator to find out weak spots to engineering thermostability of proteins. However, the relationship among flexibility, activity and stability in most of proteins is unclear. Proline is the most rigid residue and can be introduced to rigidify flexible regions to enhance thermostability of proteins. We firstly apply three different methods, molecular dynamics (MD) simulation, B-FITTER and framework rigidity optimized dynamics algorithm (FRODA) to determine the flexible regions of Photinus pyralis luciferase: Fragment 197-207; Fragment 471-481 and Fragment 487-495. Then, introduction of proline is used to rigidify these flexible regions. Two mutants D476P and H489P within most flexible regions are finally designed. In the results, H489P mutant shows improved thermostability while maintaining its catalytic efficiency compared to that of wild type luciferase. Flexibility analysis confirms that the overall rigidity and local rigidity of H489P mutant are greatly strengthened. D476P mutant shows decreased thermosatbility and the reason for this is elucidated at the molecular level. S307P mutation is randomly chosen outside the flexible regions as a control. Thermostability analysis shows that S307P mutation has decreased kinetic stability and enhanced thermodynamic stability. Copyright © 2014 Elsevier B.V. All rights reserved.

Modelling of structural flexiblity in multibody railroad vehicle systems

NASA Astrophysics Data System (ADS)

Escalona, José L.; Sugiyama, Hiroyuki; Shabana, Ahmed A.

2013-07-01

This paper presents a review of recent research investigations on the computer modelling of flexible bodies in railroad vehicle systems. The paper will also discuss the influence of the structural flexibility of various components, including the wheelset, the truck frames, tracks, pantograph/catenary systems, and car bodies, on the dynamics of railroad vehicles. While several formulations and computer techniques for modelling structural flexibility are discussed in this paper, a special attention is paid to the floating frame of reference formulation which is widely used and leads to reduced-order finite-element models for flexible bodies by employing component modes synthesis techniques. Other formulations and numerical methods such as semi-analytical approaches, absolute nodal coordinate formulation, finite-segment method, boundary elements method, and discrete elements method are also discussed. This investigation is motivated by the fact that the structural flexibility can have a significant effect on the overall dynamics of railroad vehicles, ride comfort, vibration suppression and noise level reduction, lateral stability, track response to vehicle forces, stress analysis, wheel-rail contact forces, wear and crashworthiness.

An adaptive learning control system for large flexible structures

NASA Technical Reports Server (NTRS)

Thau, F. E.

1985-01-01

The objective of the research has been to study the design of adaptive/learning control systems for the control of large flexible structures. In the first activity an adaptive/learning control methodology for flexible space structures was investigated. The approach was based on using a modal model of the flexible structure dynamics and an output-error identification scheme to identify modal parameters. In the second activity, a least-squares identification scheme was proposed for estimating both modal parameters and modal-to-actuator and modal-to-sensor shape functions. The technique was applied to experimental data obtained from the NASA Langley beam experiment. In the third activity, a separable nonlinear least-squares approach was developed for estimating the number of excited modes, shape functions, modal parameters, and modal amplitude and velocity time functions for a flexible structure. In the final research activity, a dual-adaptive control strategy was developed for regulating the modal dynamics and identifying modal parameters of a flexible structure. A min-max approach was used for finding an input to provide modal parameter identification while not exceeding reasonable bounds on modal displacement.

Propulsion via flexible flapping in granular media

NASA Astrophysics Data System (ADS)

Peng, Zhiwei; Ding, Yang; Pietrzyk, Kyle; Elfring, Gwynn; Pak, On Shun

2017-11-01

Biological locomotion in nature is often achieved by the interaction between a flexible body and its surrounding medium. The interaction of a flexible body with granular media is less understood compared with viscous fluids partially due to its complex rheological properties. In this work, we explore the effect of flexibility on granular propulsion by considering a simple mechanical model in which a rigid rod is connected to a torsional spring that is under a displacement actuation using a granular resistive force theory. Through a combined numerical and asymptotic investigation, we characterize the propulsive dynamics of such a flexible flapper in relation to the actuation amplitude and spring stiffness, and we compare these dynamics with those observed in a viscous fluid. In addition, we demonstrate that the maximum possible propulsive force can be obtained in the steady propulsion limit with a finite spring stiffness and large actuation amplitude. These results may apply to the development of synthetic locomotive systems that exploit flexibility to move through complex terrestrial media. Funding for Z.P. and Y.D. was partially provided by NSFC 394 Grant No. 11672029 and NSAF-NSFC Grant No. U1530401.

A phase transition induces chaos in a predator-prey ecosystem with a dynamic fitness landscape.

PubMed

Gilpin, William; Feldman, Marcus W

2017-07-01

In many ecosystems, natural selection can occur quickly enough to influence the population dynamics and thus future selection. This suggests the importance of extending classical population dynamics models to include such eco-evolutionary processes. Here, we describe a predator-prey model in which the prey population growth depends on a prey density-dependent fitness landscape. We show that this two-species ecosystem is capable of exhibiting chaos even in the absence of external environmental variation or noise, and that the onset of chaotic dynamics is the result of the fitness landscape reversibly alternating between epochs of stabilizing and disruptive selection. We draw an analogy between the fitness function and the free energy in statistical mechanics, allowing us to use the physical theory of first-order phase transitions to understand the onset of rapid cycling in the chaotic predator-prey dynamics. We use quantitative techniques to study the relevance of our model to observational studies of complex ecosystems, finding that the evolution-driven chaotic dynamics confer community stability at the "edge of chaos" while creating a wide distribution of opportunities for speciation during epochs of disruptive selection-a potential observable signature of chaotic eco-evolutionary dynamics in experimental studies.

Physical fitness and levels of physical activity in people with severe mental illness: a cross-sectional study.

PubMed

Perez-Cruzado, David; Cuesta-Vargas, Antonio I; Vera-Garcia, Elisa; Mayoral-Cleries, Fermín

2017-01-01

Physical fitness is a crucial variable in people with severe mental illness as these people could be more independent and improve their job opportunities. The present study compared the physical fitness of physically active and inactive people with severe mental illness. Physical fitness was evaluated in sixty-two people with severe mental illness using 11 physical tests that include strength, flexibility, balance and aerobic condition. Significant differences were found between both groups in muscle strength (handgrip test) and balance (single leg balance test and functional reach) with better performance in the group of physically active people. The results of the present study suggest that physical fitness (strength and balance) is higher in people with severe mental illness who practise regular physical activity that those who are inactive people. Physical active people may have a reduced risk of falls and fractures due to their higher levels of physical fitness.

Is HDF5 a Good Format to Replace UVFITS?

NASA Astrophysics Data System (ADS)

Price, D. C.; Barsdell, B. R.; Greenhill, L. J.

2015-09-01

The FITS (Flexible Image Transport System) data format was developed in the late 1970s for storage and exchange of astronomy-related image data. Since then, it has become a standard file format not only for images, but also for radio interferometer data (e.g. UVFITS, FITS-IDI). But is FITS the right format for next-generation telescopes to adopt? The newer Hierarchical Data Format (HDF5) file format offers considerable advantages over FITS, but has yet to gain widespread adoption within the radio astronomy. One of the major holdbacks is that HDF5 is not well supported by data reduction software packages. Here, we present a comparison of FITS, HDF5, and the MeasurementSet (MS) format for storage of interferometric data. In addition, we present a tool for converting between formats. We show that the underlying data model of FITS can be ported to HDF5, a first step toward achieving wider HDF5 support.

Unsymmetric Lanczos model reduction and linear state function observer for flexible structures

NASA Technical Reports Server (NTRS)

Su, Tzu-Jeng; Craig, Roy R., Jr.

1991-01-01

This report summarizes part of the research work accomplished during the second year of a two-year grant. The research, entitled 'Application of Lanczos Vectors to Control Design of Flexible Structures' concerns various ways to use Lanczos vectors and Krylov vectors to obtain reduced-order mathematical models for use in the dynamic response analyses and in control design studies. This report presents a one-sided, unsymmetric block Lanczos algorithm for model reduction of structural dynamics systems with unsymmetric damping matrix, and a control design procedure based on the theory of linear state function observers to design low-order controllers for flexible structures.

Flexible docking of a ligand peptide to a receptor protein by multicanonical molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Nakajima, Nobuyuki; Higo, Junichi; Kidera, Akinori; Nakamura, Haruki

1997-10-01

A new method for flexible docking by multicanonical molecular dynamics simulation is presented. The method was applied to the binding of a short proline-rich peptide to a Src homology 3 (SH3) domain. The peptide and the side-chains at the ligand binding cleft of SH3 were completely flexible and the large number of possible conformations and dispositions of the peptide were sampled. The reweighted canonical resemble at 300 K resulted in only a few predominant binding modes, one of which was similar to the complex crystal structure. The inverted peptide orientation was also observed in the other binding modes.

High speed, precision motion strategies for lightweight structures

NASA Technical Reports Server (NTRS)

Book, Wayne J.

1989-01-01

Research on space telerobotics is summarized. Adaptive control experiments on the Robotic Arm, Large and Flexible (RALF) were preformed and are documented, along with a joint controller design for the Small Articulated Manipulator (SAM), which is mounted on the RALF. A control algorithm is described as a robust decentralized adaptive control based on a bounded uncertainty approach. Dynamic interactions between SAM and RALF are examined. Unstability of the manipulator is studied from the perspective that the inertial forces generated could actually be used to more rapidly damp out the flexible manipulator's vibration. Currently being studied is the modeling of the constrained dynamics of flexible arms.

Specialized Dynamical Properties of Promiscuous Residues Revealed by Simulated Conformational Ensembles

PubMed Central

2013-01-01

The ability to interact with different partners is one of the most important features in proteins. Proteins that bind a large number of partners (hubs) have been often associated with intrinsic disorder. However, many examples exist of hubs with an ordered structure, and evidence of a general mechanism promoting promiscuity in ordered proteins is still elusive. An intriguing hypothesis is that promiscuous binding sites have specific dynamical properties, distinct from the rest of the interface and pre-existing in the protein isolated state. Here, we present the first comprehensive study of the intrinsic dynamics of promiscuous residues in a large protein data set. Different computational methods, from coarse-grained elastic models to geometry-based sampling methods and to full-atom Molecular Dynamics simulations, were used to generate conformational ensembles for the isolated proteins. The flexibility and dynamic correlations of interface residues with a different degree of binding promiscuity were calculated and compared considering side chain and backbone motions, the latter both on a local and on a global scale. The study revealed that (a) promiscuous residues tend to be more flexible than nonpromiscuous ones, (b) this additional flexibility has a higher degree of organization, and (c) evolutionary conservation and binding promiscuity have opposite effects on intrinsic dynamics. Findings on simulated ensembles were also validated on ensembles of experimental structures extracted from the Protein Data Bank (PDB). Additionally, the low occurrence of single nucleotide polymorphisms observed for promiscuous residues indicated a tendency to preserve binding diversity at these positions. A case study on two ubiquitin-like proteins exemplifies how binding promiscuity in evolutionary related proteins can be modulated by the fine-tuning of the interface dynamics. The interplay between promiscuity and flexibility highlighted here can inspire new directions in protein–protein interaction prediction and design methods. PMID:24250278

Structural domains and main-chain flexibility in prion proteins.

PubMed

Blinov, N; Berjanskii, M; Wishart, D S; Stepanova, M

2009-02-24

In this study we describe a novel approach to define structural domains and to characterize the local flexibility in both human and chicken prion proteins. The approach we use is based on a comprehensive theory of collective dynamics in proteins that was recently developed. This method determines the essential collective coordinates, which can be found from molecular dynamics trajectories via principal component analysis. Under this particular framework, we are able to identify the domains where atoms move coherently while at the same time to determine the local main-chain flexibility for each residue. We have verified this approach by comparing our results for the predicted dynamic domain systems with the computed main-chain flexibility profiles and the NMR-derived random coil indexes for human and chicken prion proteins. The three sets of data show excellent agreement. Additionally, we demonstrate that the dynamic domains calculated in this fashion provide a highly sensitive measure of protein collective structure and dynamics. Furthermore, such an analysis is capable of revealing structural and dynamic properties of proteins that are inaccessible to the conventional assessment of secondary structure. Using the collective dynamic simulation approach described here along with a high-temperature simulations of unfolding of human prion protein, we have explored whether locations of relatively low stability could be identified where the unfolding process could potentially be facilitated. According to our analysis, the locations of relatively low stability may be associated with the beta-sheet formed by strands S1 and S2 and the adjacent loops, whereas helix HC appears to be a relatively stable part of the protein. We suggest that this kind of structural analysis may provide a useful background for a more quantitative assessment of potential routes of spontaneous misfolding in prion proteins.

Dynamics of a gravity-gradient stabilized flexible spacecraft

NASA Technical Reports Server (NTRS)

Meirovitch, L.; Juang, J. N.

1974-01-01

The dynamics of gravity-gradient stabilized flexible satellite in the neighborhood of a deformed equilibrium configuration are discussed. First the equilibrium configuration was determined by solving a set of nonlinear differential equations. Then stability of motion about the deformed equilibrium was tested by means of the Liapunov direct method. The natural frequencies of oscillation of the complete structure were calculated. The analysis is applicable to the RAE/B satellite.

Molecular Dynamics of Flexible Polar Cations in a Variable Confined Space: Toward Exceptional Two-Step Nonlinear Optical Switches.

PubMed

Xu, Wei-Jian; He, Chun-Ting; Ji, Cheng-Min; Chen, Shao-Li; Huang, Rui-Kang; Lin, Rui-Biao; Xue, Wei; Luo, Jun-Hua; Zhang, Wei-Xiong; Chen, Xiao-Ming

2016-07-01

The changeable molecular dynamics of flexible polar cations in the variable confined space between inorganic chains brings about a new type of two-step nonlinear optical (NLO) switch with genuine "off-on-off" second harmonic generation (SHG) conversion between one NLO-active state and two NLO-inactive states. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preliminary results on the dynamics of large and flexible space structures in Halo orbits

NASA Astrophysics Data System (ADS)

Colagrossi, Andrea; Lavagna, Michèle

2017-05-01

The global exploration roadmap suggests, among other ambitious future space programmes, a possible manned outpost in lunar vicinity, to support surface operations and further astronaut training for longer and deeper space missions and transfers. In particular, a Lagrangian point orbit location - in the Earth- Moon system - is suggested for a manned cis-lunar infrastructure; proposal which opens an interesting field of study from the astrodynamics perspective. Literature offers a wide set of scientific research done on orbital dynamics under the Three-Body Problem modelling approach, while less of it includes the attitude dynamics modelling as well. However, whenever a large space structure (ISS-like) is considered, not only the coupled orbit-attitude dynamics should be modelled to run more accurate analyses, but the structural flexibility should be included too. The paper, starting from the well-known Circular Restricted Three-Body Problem formulation, presents some preliminary results obtained by adding a coupled orbit-attitude dynamical model and the effects due to the large structure flexibility. In addition, the most relevant perturbing phenomena, such as the Solar Radiation Pressure (SRP) and the fourth-body (Sun) gravity, are included in the model as well. A multi-body approach has been preferred to represent possible configurations of the large cis-lunar infrastructure: interconnected simple structural elements - such as beams, rods or lumped masses linked by springs - build up the space segment. To better investigate the relevance of the flexibility effects, the lumped parameters approach is compared with a distributed parameters semi-analytical technique. A sensitivity analysis of system dynamics, with respect to different configurations and mechanical properties of the extended structure, is also presented, in order to highlight drivers for the lunar outpost design. Furthermore, a case study for a large and flexible space structure in Halo orbits around one of the Earth-Moon collinear Lagrangian points, L1 or L2, is discussed to point out some relevant outcomes for the potential implementation of such a mission.

Differential Enzyme Flexibility Probed Using Solid-State Nanopores.

PubMed

Hu, Rui; Rodrigues, João V; Waduge, Pradeep; Yamazaki, Hirohito; Cressiot, Benjamin; Chishti, Yasmin; Makowski, Lee; Yu, Dapeng; Shakhnovich, Eugene; Zhao, Qing; Wanunu, Meni

2018-05-22

Enzymes and motor proteins are dynamic macromolecules that coexist in a number of conformations of similar energies. Protein function is usually accompanied by a change in structure and flexibility, often induced upon binding to ligands. However, while measuring protein flexibility changes between active and resting states is of therapeutic significance, it remains a challenge. Recently, our group has demonstrated that breadth of signal amplitudes in measured electrical signatures as an ensemble of individual protein molecules is driven through solid-state nanopores and correlates with protein conformational dynamics. Here, we extend our study to resolve subtle flexibility variation in dihydrofolate reductase mutants from unlabeled single molecules in solution. We first demonstrate using a canonical protein system, adenylate kinase, that both size and flexibility changes can be observed upon binding to a substrate that locks the protein in a closed conformation. Next, we investigate the influence of voltage bias and pore geometry on the measured electrical pulse statistics during protein transport. Finally, using the optimal experimental conditions, we systematically study a series of wild-type and mutant dihydrofolate reductase proteins, finding a good correlation between nanopore-measured protein conformational dynamics and equilibrium bulk fluorescence probe measurements. Our results unequivocally demonstrate that nanopore-based measurements reliably probe conformational diversity in native protein ensembles.

Attitude dynamics and control of spacecraft with a partially filled liquid tank and flexible panels

NASA Astrophysics Data System (ADS)

Liu, Feng; Yue, Baozeng; Zhao, Liangyu

2018-02-01

A liquid-filled flexible spacecraft is essentially a time-variant fully-coupled system, whose dynamics characteristics are closely associated with its motion features. This paper focuses on the mathematical modelling and attitude control of the spacecraft coupled with fuel sloshing dynamics and flexible solar panels vibration. The slosh motion is represented by a spherical pendulum, whose motion description method is improved by using split variable operation. Benefiting from this improvement, the nonlinear lateral sloshing and the rotary sloshing as well as the rigid motion of a liquid respect to the spacecraft can be approximately described. The assumed modes discretization method has been adopted to approximate the elastic displacements of the attached panels, and the coupled dynamics is derived by using the Lagrangian formulation. A variable substitution method is proposed to obtain the apparently-uncoupled mathematical model of the rigid-flexible-liquid spacecraft. After linearization, this model can be directly used for designing Lyapunov output-feedback attitude controller (OFAC). With only torque actuators, and attitude and rate sensors installed, this kind of attitude controller, as simulation results show, is capable of not only bringing the spacecraft to the desired orientation, but also suppressing the effect of flex and slosh on the attitude motion of the spacecraft.

Dynamic Characteristics of Micro-Beams Considering the Effect of Flexible Supports

PubMed Central

Zhong, Zuo-Yang; Zhang, Wen-Ming; Meng, Guang

2013-01-01

Normally, the boundaries are assumed to allow small deflections and moments for MEMS beams with flexible supports. The non-ideal boundary conditions have a significant effect on the qualitative dynamical behavior. In this paper, by employing the principle of energy equivalence, rigorous theoretical solutions of the tangential and rotational equivalent stiffness are derived based on the Boussinesq's and Cerruti's displacement equations. The non-dimensional differential partial equation of the motion, as well as coupled boundary conditions, are solved analytically using the method of multiple time scales. The closed-form solution provides a direct insight into the relationship between the boundary conditions and vibration characteristics of the dynamic system, in which resonance frequencies increase with the nonlinear mechanical spring effect but decrease with the effect of flexible supports. The obtained results of frequencies and mode shapes are compared with the cases of ideal boundary conditions, and the differences between them are contrasted on frequency response curves. The influences of the support material property on the equivalent stiffness and resonance frequency shift are also discussed. It is demonstrated that the proposed model with the flexible supports boundary conditions has significant effect on the rigorous quantitative dynamical analysis of the MEMS beams. Moreover, the proposed analytical solutions are in good agreement with those obtained from finite element analyses.

The effect of dynamic stretching on hamstrings flexibility with respect to the spino-pelvic rhythm.

PubMed

Hasebe, Kiyotaka; Okubo, Yu; Kaneoka, Koji; Takada, Kohei; Suzuki, Daisuke; Sairyo, Koichi

2016-01-01

To ascertain the dynamic stretch effects of flexibility of the hamstrings on lumbar spine and pelvic kinematics. Tight hamstrings are positively correlated with low back pain. However, it is unclear how flexibility of the hamstrings affects spino-pelvic rhythm. Twelve healthy men participated in the study. The straight leg raising (SLR) angle, finger floor distance (FFD), and spino-pelvic rhythm was measured before and after the 6-week stretching protocol. The forward bending task was divided into 4 phases. The paired t-test was used to determine significant differences before and after the FFD, SLR angle, lumbar motion, and pelvic motion, and spino-pelvic rhythm in each phase (p<0.05). After 6 weeks of stretching, significant improvements were seen in the FFD with maximum forward bending and in the SLR angle. Total pelvic rotation was also significantly increased in contrast to total lumbar flexion. A decreased spino-pelvic ratio was seen in the final phase. Dynamic stretching could change the spino-pelvic rhythm to a pelvis-dominant motion, indicating that flexible hamstrings are important for preventing low back pain.

On-the-fly form generation and on-line metadata configuration--a clinical data management Web infrastructure in Java.

PubMed

Beck, Peter; Truskaller, Thomas; Rakovac, Ivo; Cadonna, Bruno; Pieber, Thomas R

2006-01-01

In this paper we describe the approach to build a web-based clinical data management infrastructure on top of an entity-attribute-value (EAV) database which provides for flexible definition and extension of clinical data sets as well as efficient data handling and high performance query execution. A "mixed" EAV implementation provides a flexible and configurable data repository and at the same time utilizes the performance advantages of conventional database tables for rarely changing data structures. A dynamically configurable data dictionary contains further information for data validation. The online user interface can also be assembled dynamically. A data transfer object which encapsulates data together with all required metadata is populated by the backend and directly used to dynamically render frontend forms and handle incoming data. The "mixed" EAV model enables flexible definition and modification of clinical data sets while reducing performance drawbacks of pure EAV implementations to a minimum. The system currently is in use in an electronic patient record with focus on flexibility and a quality management application (www.healthgate.at) with high performance requirements.

Vagal Flexibility: A Physiological Predictor of Social Sensitivity

PubMed Central

Muhtadie, Luma; Akinola, Modupe; Koslov, Katrina; Mendes, Wendy Berry

2015-01-01

This research explores vagal flexibility— dynamic modulation of cardiac vagal control—as an individual-level physiological index of social sensitivity. In 4 studies, we test the hypothesis that individuals with greater cardiac vagal flexibility, operationalized as higher cardiac vagal tone at rest and greater cardiac vagal withdrawal (indexed by a decrease in respiratory sinus arrhythmia) during cognitive or attentional demand, perceive social-emotional information more accurately and show greater sensitivity to their social context. Study 1 sets the foundation for this investigation by establishing that vagal flexibility can be elicited consistently in the laboratory and reliably over time. Study 2 demonstrates that vagal flexibility has different associations with psychological characteristics than does vagal tone, and that these characteristics are primarily social in nature. Study 3 links individual differences in vagal flexibility with accurate detection of social and emotional cues depicted in still facial images. Study 4 demonstrates that individuals with greater vagal flexibility respond to dynamic social feedback in a more context-sensitive manner than do individuals with less vagal flexibility. Specifically, compared with their less flexible counterparts, individuals with greater vagal flexibility, when assigned to receive negative social feedback, report more shame, show more pronounced blood pressure responses, and display less sociable behavior, but when receiving positive social feedback display more sociable behavior. Taken together, these findings suggest that vagal flexibility is a useful individual difference physiological predictor of social sensitivity, which may have implications for clinical, developmental, and health psychologists. PMID:25545841

Negotiating Boundaries through Flexibility, Capacity, and Agility in Adult Education

ERIC Educational Resources Information Center

Nanton, Carmela R.

2016-01-01

This chapter summarizes key convergent, divergent, and transforming forces of adult education. Super-flexibility is proposed as a postmodern strategy for effective, sustainable negotiated existence in global dynamic contexts.

Dynamic Modeling of the SMAP Rotating Flexible Antenna

NASA Technical Reports Server (NTRS)

Nayeri, Reza D.

2012-01-01

Dynamic model development in ADAMS for the SMAP project is explained: The main objective of the dynamic models are for pointing error assessment, and the control/stability margin requirement verifications

Cost-effectiveness of population-based screening for colorectal cancer: a comparison of guaiac-based faecal occult blood testing, faecal immunochemical testing and flexible sigmoidoscopy

PubMed Central

Sharp, L; Tilson, L; Whyte, S; O'Ceilleachair, A; Walsh, C; Usher, C; Tappenden, P; Chilcott, J; Staines, A; Barry, M; Comber, H

2012-01-01

Background: Several colorectal cancer-screening tests are available, but it is uncertain which provides the best balance of risks and benefits within a screening programme. We evaluated cost-effectiveness of a population-based screening programme in Ireland based on (i) biennial guaiac-based faecal occult blood testing (gFOBT) at ages 55–74, with reflex faecal immunochemical testing (FIT); (ii) biennial FIT at ages 55–74; and (iii) once-only flexible sigmoidoscopy (FSIG) at age 60. Methods: A state-transition model was used to estimate costs and outcomes for each screening scenario vs no screening. A third party payer perspective was adopted. Probabilistic sensitivity analyses were undertaken. Results: All scenarios would be considered highly cost-effective compared with no screening. The lowest incremental cost-effectiveness ratio (ICER vs no screening €589 per quality-adjusted life-year (QALY) gained) was found for FSIG, followed by FIT (€1696) and gFOBT (€4428); gFOBT was dominated. Compared with FSIG, FIT was associated with greater gains in QALYs and reductions in lifetime cancer incidence and mortality, but was more costly, required considerably more colonoscopies and resulted in more complications. Results were robust to variations in parameter estimates. Conclusion: Population-based screening based on FIT is expected to result in greater health gains than a policy of gFOBT (with reflex FIT) or once-only FSIG, but would require significantly more colonoscopy resources and result in more individuals experiencing adverse effects. Weighing these advantages and disadvantages presents a considerable challenge to policy makers. PMID:22343624

Musculoskeletal Fitness Measures Are Not Created Equal: An Assessment of School Children in Corpus Christi, Texas

PubMed Central

Ajisafe, Toyin; Garcia, Theresa; Fanchiang, Hsin-Chen

2018-01-01

This study investigated current obesity prevalence and associations between musculoskeletal fitness test scores and the odds of being underweight, overweight, or obese compared to having a healthy weight in elementary school children in Corpus Christi, Texas. The sample analyzed consisted of 492 public elementary school children between kindergarten and fifth grade. Their ages ranged from 5 to 11 years. Trunk lift, 90° push-up, curl-up, and back saver sit and reach tests were administered. Weight status was determined using BMI scores and the CDC growth charts. Obesity prevalence remains high among elementary school-aged children in Corpus Christi, Texas. Higher 90° push-up test scores were most consistently associated with decreased odds of being obese as compared to being overweight and having healthy weight except in kindergarten. Conversely, higher trunk lift test scores were associated with increased odds of being obese in second and fourth grades. When children achieved the minimum score to be classified in the Healthy Fitness Zone, those with healthy weight had similarly low musculoskeletal fitness (i.e., abdominal strength and endurance, hamstring flexibility, and trunk extensor strength and flexibility) as peers with overweight and obesity, especially in the lower grades. It was concluded that increased obesity prevalence in higher grades may be precipitated (at least in part) by low musculoskeletal fitness in the lower grades, especially kindergarten. Given previous associations in the literature, low musculoskeletal fitness may be symptomatic of poor motor skill competence in the current sample. These findings suggest a need for early and focused school-based interventions that leverage both known and novel strategies to combat pediatric obesity in Corpus Christi. PMID:29872650

Association of objectively measured physical activity and physical fitness with menopause symptoms. The Flamenco Project.

PubMed

Aparicio, V A; Borges-Cosic, M; Ruiz-Cabello, P; Coll-Risco, I; Acosta-Manzano, P; Špacírová, Z; Soriano-Maldonado, A

2017-10-01

The primary aim was to analyze the association of moderate-to-vigorous physical activity (MVPA) with menopause symptomatology and its overall impact. A secondary/exploratory aim was to assess the association of different components of physical fitness with menopause symptomatology. This cross-sectional study comprised 191 perimenopausal women from Southern Spain (age range 45-60 years, mean age 52.6 ± 4.5 years). The Blatt-Kupperman Menopausal Index was used to evaluate menopause symptomatology. Objectively measured MVPA was registered with accelerometry. Physical fitness was assessed with the Senior Fitness Test battery plus handgrip strength and sit-and-reach tests. After adjustment for multiple confounders, MVPA was only inversely associated with vertigo (r = -0.185, p < 0.05) and palpitations (r = -0.148, p < 0.05). Upper-body flexibility was inversely associated with the Blatt-Kupperman Menopausal Index global score (r = -0.147, p < 0.05). This test was also inversely associated with vertigo (r = -0.230, p < 0.01) and arthralgia (r = -0.168, p < 0.05). Lower-body muscle strength was associated with lower nervousness (r = -0.171, p < 0.05). Cardiorespiratory fitness was inversely associated with paresthesia (r = -0.158, p < 0.05), vertigo (r = -0.219, p < 0.01), fatigue (r = -0.159, p < 0.05) and arthralgia (r = -0.180, p < 0.05). The main findings of the present study indicate a weak association of objectively measured MVPA with menopause symptomatology. Exploratory analyses suggest that upper-body flexibility was associated with slightly lower overall menopause impact whereas neither MVPA nor any physical fitness components studied were associated with vasomotor symptoms.

Health-related physical fitness assessment in a community-based cancer rehabilitation setting.

PubMed

Kirkham, Amy A; Neil-Sztramko, Sarah E; Morgan, Joanne; Hodson, Sara; Weller, Sarah; McRae, Tasha; Campbell, Kristin L

2015-09-01

Assessment of physical fitness is important in order to set goals, appropriately prescribe exercise, and monitor change over time. This study aimed to determine the utility of a standardized physical fitness assessment for use in cancer-specific, community-based exercise programs. Tests anticipated to be feasible and suitable for a community setting and a wide range of ages and physical function were chosen to measure body composition, aerobic fitness, strength, flexibility, and balance. Cancer Exercise Trainers/Specialists at cancer-specific, community-based exercise programs assessed new clients (n = 60) at enrollment, designed individualized exercise programs, and then performed a re-assessment 3-6 months later (n = 34). Resting heart rate, blood pressure, body mass index, waist circumference, handgrip strength, chair stands, sit-and-reach, back scratch, single-leg standing, and timed up-and-go tests were considered suitable and feasible tests/measures, as they were performed in most (≥88 %) participants. The ability to capture change was also noted for resting blood pressure (-7/-5 mmHg, p = 0.02), chair stands (+4, p < 0.01), handgrip strength (+2 kg, p < 0.01), and sit-and-reach (+3 cm, p = 0.03). While the submaximal treadmill test captured a meaningful improvement in aerobic fitness (+62 s, p = 0.17), it was not completed in 33 % of participants. Change in mobility, using the timed up-and-go was nominal and was not performed in 27 %. Submaximal treadmill testing, handgrip dynamometry, chair stands, and sit-and-reach tests were feasible, suitable, and provided meaningful physical fitness information in a cancer-specific, community-based, exercise program setting. However, a shorter treadmill protocol and more sensitive balance and upper body flexibility tests should be investigated.

Musculoskeletal Fitness Measures Are Not Created Equal: An Assessment of School Children in Corpus Christi, Texas.

PubMed

Ajisafe, Toyin; Garcia, Theresa; Fanchiang, Hsin-Chen

2018-01-01

This study investigated current obesity prevalence and associations between musculoskeletal fitness test scores and the odds of being underweight, overweight, or obese compared to having a healthy weight in elementary school children in Corpus Christi, Texas. The sample analyzed consisted of 492 public elementary school children between kindergarten and fifth grade. Their ages ranged from 5 to 11 years. Trunk lift, 90° push-up, curl-up, and back saver sit and reach tests were administered. Weight status was determined using BMI scores and the CDC growth charts. Obesity prevalence remains high among elementary school-aged children in Corpus Christi, Texas. Higher 90° push-up test scores were most consistently associated with decreased odds of being obese as compared to being overweight and having healthy weight except in kindergarten. Conversely, higher trunk lift test scores were associated with increased odds of being obese in second and fourth grades. When children achieved the minimum score to be classified in the Healthy Fitness Zone, those with healthy weight had similarly low musculoskeletal fitness (i.e., abdominal strength and endurance, hamstring flexibility, and trunk extensor strength and flexibility) as peers with overweight and obesity, especially in the lower grades. It was concluded that increased obesity prevalence in higher grades may be precipitated (at least in part) by low musculoskeletal fitness in the lower grades, especially kindergarten. Given previous associations in the literature, low musculoskeletal fitness may be symptomatic of poor motor skill competence in the current sample. These findings suggest a need for early and focused school-based interventions that leverage both known and novel strategies to combat pediatric obesity in Corpus Christi.

Performance Evaluation of the Gravity Probe B Design

NASA Technical Reports Server (NTRS)

Francis, Ronnie; Wells, Eugene M.

1996-01-01

This report documents the simulation of the Lockheed Martin designed Gravity Probe B (GPB) spacecraft developed tool by bd Systems Inc using the TREETOPS simulation. This study quantifies the effects of flexibility and liquid helium slosh on GPB spacecraft control performance. The TREETOPS simulation tool permits the simulation of flexible structures given that a flexible body model of the structure is available. For purposes of this study, a flexible model of the GPB spacecraft was obtained from Lockheed Martin. To model the liquid helium slosh effects, computational fluid dynamics (CFD) results' were obtained, and used to develop a dynamic model of the slosh effects. The flexible body and slosh effects were incorporated separately into the TREETOPS simulation, which places the vehicle in a 650 km circular polar orbit and subjects the spacecraft to realistic environmental disturbances and sensor error quantities. In all of the analysis conducted in this study the spacecraft is pointed at an inertially fixed guide star (GS) and is rotating at a constant rate about this line of sight.

Instability of a cantilevered flexible plate in viscous channel flow

NASA Astrophysics Data System (ADS)

Balint, T. S.; Lucey, A. D.

2005-10-01

The stability of a flexible cantilevered plate in viscous channel flow is studied as a representation of the dynamics of the human upper airway. The focus is on instability mechanisms of the soft palate (flexible plate) that cause airway blockage during sleep. We solve the Navier Stokes equations for flow with Reynolds numbers up to 1500 fully coupled with the dynamics of the plate motion solved using finite-differences. The study is 2-D and based upon linearized plate mechanics. When both upper and lower airways are open, the plate is found to lose its stability through a flutter mechanism and a critical Reynolds number exists. When one airway is closed, the plate principally loses its stability through a divergence mechanism and a critical flow speed exists. However, below the divergence-onset flow speed, flutter can exist for low levels of structural damping in the flexible plate. Our results serve to extend understanding of flow-induced instability of cantilevered flexible plates and will ultimately improve the diagnosis and treatment of upper-airway disorders.

Robust lateral blended-wing-body aircraft feedback control design using a parameterized LFR model and DGK-iteration

NASA Astrophysics Data System (ADS)

Schirrer, A.; Westermayer, C.; Hemedi, M.; Kozek, M.

2013-12-01

This paper shows control design results, performance, and limitations of robust lateral control law designs based on the DGK-iteration mixed-μ-synthesis procedure for a large, flexible blended wing body (BWB) passenger aircraft. The aircraft dynamics is preshaped by a low-complexity inner loop control law providing stabilization, basic response shaping, and flexible mode damping. The μ controllers are designed to further improve vibration damping of the main flexible modes by exploiting the structure of the arising significant parameter-dependent plant variations. This is achieved by utilizing parameterized Linear Fractional Representations (LFR) of the aircraft rigid and flexible dynamics. Designs with various levels of LFR complexity are carried out and discussed, showing the achieved performance improvement over the initial controller and their robustness and complexity properties.

A pressure and shear sensor system for stress measurement at lower limb residuum/socket interface.

PubMed

Laszczak, P; McGrath, M; Tang, J; Gao, J; Jiang, L; Bader, D L; Moser, D; Zahedi, S

2016-07-01

A sensor system for measurement of pressure and shear at the lower limb residuum/socket interface is described. The system comprises of a flexible sensor unit and a data acquisition unit with wireless data transmission capability. Static and dynamic performance of the sensor system was characterised using a mechanical test machine. The static calibration results suggest that the developed sensor system presents high linearity (linearity error ≤ 3.8%) and resolution (0.9 kPa for pressure and 0.2 kPa for shear). Dynamic characterisation of the sensor system shows hysteresis error of approximately 15% for pressure and 8% for shear. Subsequently, a pilot amputee walking test was conducted. Three sensors were placed at the residuum/socket interface of a knee disarticulation amputee and simultaneous measurements were obtained during pilot amputee walking test. The pressure and shear peak values as well as their temporal profiles are presented and discussed. In particular, peak pressure and shear of approximately 58 kPa and 27 kPa, respectively, were recorded. Their temporal profiles also provide dynamic coupling information at this critical residuum/socket interface. These preliminary amputee test results suggest strong potential of the developed sensor system for exploitation as an assistive technology to facilitate socket design, socket fit and effective monitoring of lower limb residuum health. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Dynamics driving function: new insights from electron transferring flavoproteins and partner complexes.

PubMed

Toogood, Helen S; Leys, David; Scrutton, Nigel S

2007-11-01

Electron transferring flavoproteins (ETFs) are soluble heterodimeric FAD-containing proteins that function primarily as soluble electron carriers between various flavoprotein dehydrogenases. ETF is positioned at a key metabolic branch point, responsible for transferring electrons from up to 10 primary dehydrogenases to the membrane-bound respiratory chain. Clinical mutations of ETF result in the often fatal disease glutaric aciduria type II. Structural and biophysical studies of ETF in complex with partner proteins have shown that ETF partitions the functions of partner binding and electron transfer between (a) a 'recognition loop', which acts as a static anchor at the ETF-partner interface, and (b) a highly mobile redox-active FAD domain. Together, this enables the FAD domain of ETF to sample a range of conformations, some compatible with fast interprotein electron transfer. This 'conformational sampling' enables ETF to recognize structurally distinct partners, whilst also maintaining a degree of specificity. Complex formation triggers mobility of the FAD domain, an 'induced disorder' mechanism contrasting with the more generally accepted models of protein-protein interaction by induced fit mechanisms. We discuss the implications of the highly dynamic nature of ETFs in biological interprotein electron transfer. ETF complexes point to mechanisms of electron transfer in which 'dynamics drive function', a feature that is probably widespread in biology given the modular assembly and flexible nature of biological electron transfer systems.

Predicting protein concentrations with ELISA microarray assays, monotonic splines and Monte Carlo simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daly, Don S.; Anderson, Kevin K.; White, Amanda M.

Background: A microarray of enzyme-linked immunosorbent assays, or ELISA microarray, predicts simultaneously the concentrations of numerous proteins in a small sample. These predictions, however, are uncertain due to processing error and biological variability. Making sound biological inferences as well as improving the ELISA microarray process require require both concentration predictions and creditable estimates of their errors. Methods: We present a statistical method based on monotonic spline statistical models, penalized constrained least squares fitting (PCLS) and Monte Carlo simulation (MC) to predict concentrations and estimate prediction errors in ELISA microarray. PCLS restrains the flexible spline to a fit of assay intensitymore » that is a monotone function of protein concentration. With MC, both modeling and measurement errors are combined to estimate prediction error. The spline/PCLS/MC method is compared to a common method using simulated and real ELISA microarray data sets. Results: In contrast to the rigid logistic model, the flexible spline model gave credible fits in almost all test cases including troublesome cases with left and/or right censoring, or other asymmetries. For the real data sets, 61% of the spline predictions were more accurate than their comparable logistic predictions; especially the spline predictions at the extremes of the prediction curve. The relative errors of 50% of comparable spline and logistic predictions differed by less than 20%. Monte Carlo simulation rendered acceptable asymmetric prediction intervals for both spline and logistic models while propagation of error produced symmetric intervals that diverged unrealistically as the standard curves approached horizontal asymptotes. Conclusions: The spline/PCLS/MC method is a flexible, robust alternative to a logistic/NLS/propagation-of-error method to reliably predict protein concentrations and estimate their errors. The spline method simplifies model selection and fitting, and reliably estimates believable prediction errors. For the 50% of the real data sets fit well by both methods, spline and logistic predictions are practically indistinguishable, varying in accuracy by less than 15%. The spline method may be useful when automated prediction across simultaneous assays of numerous proteins must be applied routinely with minimal user intervention.« less

41 CFR 102-79.35 - What elements must Federal agencies address in their planning effort for establishing fitness...

Code of Federal Regulations, 2010 CFR

2010-07-01

... will consider key health behavior related to degenerative disease, including smoking and nutrition. (f... cardiovascular and muscular endurance, strength activities, and flexibility. (g) Provision for equal...

40 CFR 1065.910 - PEMS auxiliary equipment for field testing.

Code of Federal Regulations, 2013 CFR

2013-07-01

... temperature rating of at least 315 °C for flexible connectors. You may use connectors with a spring-steel wire... frames, trailer hitch receivers, walk spaces, and payload tie-down fittings. We recommend mounting...

Testing of the coping flexibility hypothesis based on the dual-process theory: Relationships between coping flexibility and depressive Symptoms.

PubMed

Kato, Tsukasa

2015-12-15

According to the dual-process theory of coping flexibility (Kato, 2012), coping flexibility is the ability to discontinue an ineffective coping strategy (i.e., evaluation coping process) and implement an alternative strategy (i.e., adaptive coping process). The coping flexibility hypothesis (CFH) proposes that the ability to engage in flexible coping is related to better psychological functioning and physical health, including less depression. I the present study, participants were 393 American Whites, 429 Australian Whites, and 496 Chinese, selected from the data pool of the 2013 Coping and Health Survey (see Kato, 2014b). They completed both the Coping Flexibility Scale (Kato, 2012), which is based on the dual-process theory of coping flexibility, and the Center for Epidemiologic Studies Depression Scale (CES-D). For all nationalities and genders, evaluation coping and adaptive coping were significantly correlated with lower levels of depressive symptoms. Structural equation modeling revealed that evaluation coping was associated with lower depressive symptoms for all nationalities and genders, whereas no significant relationships between adaptive coping and depressive symptoms were found for any nationalities. Our results partially supported that the CFH fits with the dual-process theory of coping flexibility. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Non-recursive augmented Lagrangian algorithms for the forward and inverse dynamics of constrained flexible multibodies

NASA Technical Reports Server (NTRS)

Bayo, Eduardo; Ledesma, Ragnar

1993-01-01

A technique is presented for solving the inverse dynamics of flexible planar multibody systems. This technique yields the non-causal joint efforts (inverse dynamics) as well as the internal states (inverse kinematics) that produce a prescribed nominal trajectory of the end effector. A non-recursive global Lagrangian approach is used in formulating the equations for motion as well as in solving the inverse dynamics equations. Contrary to the recursive method previously presented, the proposed method solves the inverse problem in a systematic and direct manner for both open-chain as well as closed-chain configurations. Numerical simulation shows that the proposed procedure provides an excellent tracking of the desired end effector trajectory.

Flexible Animation Computer Program

NASA Technical Reports Server (NTRS)

Stallcup, Scott S.

1990-01-01

FLEXAN (Flexible Animation), computer program animating structural dynamics on Evans and Sutherland PS300-series graphics workstation with VAX/VMS host computer. Typical application is animation of spacecraft undergoing structural stresses caused by thermal and vibrational effects. Displays distortions in shape of spacecraft. Program displays single natural mode of vibration, mode history, or any general deformation of flexible structure. Written in FORTRAN 77.

Effects of a 12-Week Physical Activity Protocol Delivered by YMCA After-School Counselors (Youth Fit for Life) on Fitness and Self-Efficacy Changes in 5-12-Year-Old Boys and Girls

ERIC Educational Resources Information Center

Annesi, James J.; Westcott, Wayne L.; Faigenbaum, Avery D.; Unruh, Jennifer L.

2005-01-01

To address reduced physical education (PE) in elementary schools, a 12-week physical activity protocol was tested on 5-12-year-old, primarily African American, girls (n = 226) and boys (n = 344) at 14 YMCA after-school care sites. The 3 times/week, 45-min session curriculum included cardiovascular, resistance, and flexibility training, in which…

Commission 5: Documentation and Astronomical Data

NASA Astrophysics Data System (ADS)

Norris, Raymond P.; Ohishi, Masatoshi; Genova, Françoise; Grothkopf, Uta; Malkov, Oleg Yu.; Pence, William D.; Schmitz, Marion; Hanisch, Robert J.; Zhou, Xu

IAU Commission 5 deals with data management issues, and its working groups and task groups deal specifically with information handling, with data centres and networks, with technical aspects of collection, archiving, storage and dissemination of data, with designations and classification of astronomical objects, with library services, editorial policies, computer communications, ad hoc methodologies, and with various standards, reference frames, etc., FITS, astronomys Flexible Image Transport System, the major data exchange format, is controlled, maintained and updated by the Working Group FITS.

Modeling the Multi-Body System Dynamics of a Flexible Solar Sail Spacecraft

NASA Technical Reports Server (NTRS)

Kim, Young; Stough, Robert; Whorton, Mark

2005-01-01

Solar sail propulsion systems enable a wide range of space missions that are not feasible with current propulsion technology. Hardware concepts and analytical methods have matured through ground development to the point that a flight validation mission is now realizable. Much attention has been given to modeling the structural dynamics of the constituent elements, but to date an integrated system level dynamics analysis has been lacking. Using a multi-body dynamics and control analysis tool called TREETOPS, the coupled dynamics of the sailcraft bus, sail membranes, flexible booms, and control system sensors and actuators of a representative solar sail spacecraft are investigated to assess system level dynamics and control issues. With this tool, scaling issues and parametric trade studies can be performed to study achievable performance, control authority requirements, and control/structure interaction assessments.

AXAF FITS standard for ray trace interchange

NASA Astrophysics Data System (ADS)

Hsieh, Paul F.

1993-07-01

A standard data format for the archival and transport of x-ray events generated by ray trace models is described. Upon review and acceptance by the Advanced X-ray Astrophysics Facility (AXAF) Software Systems Working Group (SSWG), this standard shall become the official AXAF data format for ray trace events. The Flexible Image Transport System (FITS) is well suited for the purposes of the standard and was selected to be the basis of the standard. FITS is both flexible and efficient and is also widely used within the astronomical community for storage and transfer of data. In addition, software to read and write FITS format files are widely available. In selecting quantities to be included within the ray trace standard, the AXAF Mission Support team, Science Instruments team, and the other contractor teams were surveyed. From the results of this survey, the following requirements were established: (1) for the scientific needs, each photon should have associated with it: position, direction, energy, and statistical weight; the standard must also accommodate path length (relative phase), and polarization. (2) a unique photon identifier is necessary for bookkeeping purposes; (3) a log of individuals, organizations, and software packages that have modified the data must be maintained in order to create an audit trail; (4) a mechanism for extensions to the basic kernel should be provided; and (5) the ray trace standard should integrate with future AXAF data product standards.

AXAF FITS standard for ray trace interchange

NASA Technical Reports Server (NTRS)

Hsieh, Paul F.

1993-01-01

A standard data format for the archival and transport of x-ray events generated by ray trace models is described. Upon review and acceptance by the Advanced X-ray Astrophysics Facility (AXAF) Software Systems Working Group (SSWG), this standard shall become the official AXAF data format for ray trace events. The Flexible Image Transport System (FITS) is well suited for the purposes of the standard and was selected to be the basis of the standard. FITS is both flexible and efficient and is also widely used within the astronomical community for storage and transfer of data. In addition, software to read and write FITS format files are widely available. In selecting quantities to be included within the ray trace standard, the AXAF Mission Support team, Science Instruments team, and the other contractor teams were surveyed. From the results of this survey, the following requirements were established: (1) for the scientific needs, each photon should have associated with it: position, direction, energy, and statistical weight; the standard must also accommodate path length (relative phase), and polarization. (2) a unique photon identifier is necessary for bookkeeping purposes; (3) a log of individuals, organizations, and software packages that have modified the data must be maintained in order to create an audit trail; (4) a mechanism for extensions to the basic kernel should be provided; and (5) the ray trace standard should integrate with future AXAF data product standards.

Structural deformation upon protein-protein interaction: A structural alphabet approach

PubMed Central

Martin, Juliette; Regad, Leslie; Lecornet, Hélène; Camproux, Anne-Claude

2008-01-01

Background In a number of protein-protein complexes, the 3D structures of bound and unbound partners significantly differ, supporting the induced fit hypothesis for protein-protein binding. Results In this study, we explore the induced fit modifications on a set of 124 proteins available in both bound and unbound forms, in terms of local structure. The local structure is described thanks to a structural alphabet of 27 structural letters that allows a detailed description of the backbone. Using a control set to distinguish induced fit from experimental error and natural protein flexibility, we show that the fraction of structural letters modified upon binding is significantly greater than in the control set (36% versus 28%). This proportion is even greater in the interface regions (41%). Interface regions preferentially involve coils. Our analysis further reveals that some structural letters in coil are not favored in the interface. We show that certain structural letters in coil are particularly subject to modifications at the interface, and that the severity of structural change also varies. These information are used to derive a structural letter substitution matrix that summarizes the local structural changes observed in our data set. We also illustrate the usefulness of our approach to identify common binding motifs in unrelated proteins. Conclusion Our study provides qualitative information about induced fit. These results could be of help for flexible docking. PMID:18307769

Structural deformation upon protein-protein interaction: a structural alphabet approach.

PubMed

Martin, Juliette; Regad, Leslie; Lecornet, Hélène; Camproux, Anne-Claude

2008-02-28

In a number of protein-protein complexes, the 3D structures of bound and unbound partners significantly differ, supporting the induced fit hypothesis for protein-protein binding. In this study, we explore the induced fit modifications on a set of 124 proteins available in both bound and unbound forms, in terms of local structure. The local structure is described thanks to a structural alphabet of 27 structural letters that allows a detailed description of the backbone. Using a control set to distinguish induced fit from experimental error and natural protein flexibility, we show that the fraction of structural letters modified upon binding is significantly greater than in the control set (36% versus 28%). This proportion is even greater in the interface regions (41%). Interface regions preferentially involve coils. Our analysis further reveals that some structural letters in coil are not favored in the interface. We show that certain structural letters in coil are particularly subject to modifications at the interface, and that the severity of structural change also varies. These information are used to derive a structural letter substitution matrix that summarizes the local structural changes observed in our data set. We also illustrate the usefulness of our approach to identify common binding motifs in unrelated proteins. Our study provides qualitative information about induced fit. These results could be of help for flexible docking.

A Stochastic Fractional Dynamics Model of Rainfall Statistics

NASA Astrophysics Data System (ADS)

Kundu, Prasun; Travis, James

2013-04-01

Rainfall varies in space and time in a highly irregular manner and is described naturally in terms of a stochastic process. A characteristic feature of rainfall statistics is that they depend strongly on the space-time scales over which rain data are averaged. A spectral model of precipitation has been developed based on a stochastic differential equation of fractional order for the point rain rate, that allows a concise description of the second moment statistics of rain at any prescribed space-time averaging scale. The model is designed to faithfully reflect the scale dependence and is thus capable of providing a unified description of the statistics of both radar and rain gauge data. The underlying dynamical equation can be expressed in terms of space-time derivatives of fractional orders that are adjusted together with other model parameters to fit the data. The form of the resulting spectrum gives the model adequate flexibility to capture the subtle interplay between the spatial and temporal scales of variability of rain but strongly constrains the predicted statistical behavior as a function of the averaging length and times scales. The main restriction is the assumption that the statistics of the precipitation field is spatially homogeneous and isotropic and stationary in time. We test the model with radar and gauge data collected contemporaneously at the NASA TRMM ground validation sites located near Melbourne, Florida and in Kwajalein Atoll, Marshall Islands in the tropical Pacific. We estimate the parameters by tuning them to the second moment statistics of the radar data. The model predictions are then found to fit the second moment statistics of the gauge data reasonably well without any further adjustment. Some data sets containing periods of non-stationary behavior that involves occasional anomalously correlated rain events, present a challenge for the model.

Hydrogen bonds in concreto and in computro: the sequel

NASA Astrophysics Data System (ADS)

Stouten, Pieter F. W.; Van Eijck, Bouke P.; Kroon, Jan

1991-02-01

In the framework of our comparative research concerning hydrogen bonding in the crystalline and liquid phases we have carried out molecular dynamics (MD) simulations of liquid methanol. Six different rigid three site models are compared. Five of them had been reported in the literature and one (OM2) we developed by a fit to the experimental molar volume, heat of vaporization and neutron weighted radial distribution function. In general the agreement with experiment is satisfactory for the different models. None of the models has an explicit hydrogen bond potential, but five of the six models show a degree of hydrogen bonding comparable to experiments on liquid methanol. The analysis of the simulation hydrogen bonds indicates that there is a distinct preference of the O⋯O axis to lie in the acceptor lone pairs plane, but hardly any for the lone pair directions. Ab initio calculations and crystal structure statistics of OH⋯O hydrogen bonds agree with this observation. The O⋯O hydrogen bond length distributions are similar for most models. The crystal structures show a sharper O⋯O distribution. Explicit introduction of harmonic motion with a quite realistic root mean square amplitude of 0.08 Å to the thermally averaged crystal distribution results in a distribution comparable to OM2 although the maximum of the former is found at shorter distance. On the basis of the analysis of the static properties of all models we conclude that our OM2, Jorgenson's OPLS and Haughney, Ferrario and McDonald's HFM1 models are good candidates for simulations of liquid methanol under isothermal, isochoric conditions. Partly flexible and completely rigid OM2 are simulated at constant pressure and with fixed volume. The flexible simulations give essentially the same (correct) results under both conditions, which is not surprising because the flexible form was fitted under both conditions. Rigid OM2 has a similar potential energy but larger pressure in the isochoric case and larger energy and far larger volume in the isobaric case. Radial distribution functions and hydrogen bond geometries are very similar for all four cases. Only in the case of the osobaric rigid methanol does the volume expansion seem to be accompanied by a slight preference for tetrahedrality around the oxygen atom.

Exposing hidden alternative backbone conformations in X-ray crystallography using qFit

DOE PAGES

Keedy, Daniel A.; Fraser, James S.; van den Bedem, Henry; ...

2015-10-27

Proteins must move between different conformations of their native ensemble to perform their functions. Crystal structures obtained from high-resolution X-ray diffraction data reflect this heterogeneity as a spatial and temporal conformational average. Although movement between natively populated alternative conformations can be critical for characterizing molecular mechanisms, it is challenging to identify these conformations within electron density maps. Alternative side chain conformations are generally well separated into distinct rotameric conformations, but alternative backbone conformations can overlap at several atomic positions. Our model building program qFit uses mixed integer quadratic programming (MIQP) to evaluate an extremely large number of combinations of sidechainmore » conformers and backbone fragments to locally explain the electron density. Here, we describe two major modeling enhancements to qFit: peptide flips and alternative glycine conformations. We find that peptide flips fall into four stereotypical clusters and are enriched in glycine residues at the n+1 position. The potential for insights uncovered by new peptide flips and glycine conformations is exemplified by HIV protease, where different inhibitors are associated with peptide flips in the “flap” regions adjacent to the inhibitor binding site. Our results paint a picture of peptide flips as conformational switches, often enabled by glycine flexibility, that result in dramatic local rearrangements. Our results furthermore demonstrate the power of large-scale computational analysis to provide new insights into conformational heterogeneity. Furthermore, improved modeling of backbone heterogeneity with high-resolution X-ray data will connect dynamics to the structure-function relationship and help drive new design strategies for inhibitors of biomedically important systems.« less

Real-time Nyquist signaling with dynamic precision and flexible non-integer oversampling.

PubMed

Schmogrow, R; Meyer, M; Schindler, P C; Nebendahl, B; Dreschmann, M; Meyer, J; Josten, A; Hillerkuss, D; Ben-Ezra, S; Becker, J; Koos, C; Freude, W; Leuthold, J

2014-01-13

We demonstrate two efficient processing techniques for Nyquist signals, namely computation of signals using dynamic precision as well as arbitrary rational oversampling factors. With these techniques along with massively parallel processing it becomes possible to generate and receive high data rate Nyquist signals with flexible symbol rates and bandwidths, a feature which is highly desirable for novel flexgrid networks. We achieved maximum bit rates of 252 Gbit/s in real-time.

A modal analysis of flexible aircraft dynamics with handling qualities implications

NASA Technical Reports Server (NTRS)

Schmidt, D. K.

1983-01-01

A multivariable modal analysis technique is presented for evaluating flexible aircraft dynamics, focusing on meaningful vehicle responses to pilot inputs and atmospheric turbulence. Although modal analysis is the tool, vehicle time response is emphasized, and the analysis is performed on the linear, time-domain vehicle model. In evaluating previously obtained experimental pitch tracking data for a family of vehicle dynamic models, it is shown that flexible aeroelastic effects can significantly affect pitch attitude handling qualities. Consideration of the eigenvalues alone, of both rigid-body and aeroelastic modes, does not explain the simulation results. Modal analysis revealed, however, that although the lowest aeroelastic mode frequency was still three times greater than the short-period frequency, the rigid-body attitude response was dominated by this aeroelastic mode. This dominance was defined in terms of the relative magnitudes of the modal residues in selected vehicle responses.

Simulation of spacecraft attitude dynamics using TREETOPS and model-specific computer Codes

NASA Technical Reports Server (NTRS)

Cochran, John E.; No, T. S.; Fitz-Coy, Norman G.

1989-01-01

The simulation of spacecraft attitude dynamics and control using the generic, multi-body code called TREETOPS and other codes written especially to simulate particular systems is discussed. Differences in the methods used to derive equations of motion--Kane's method for TREETOPS and the Lagrangian and Newton-Euler methods, respectively, for the other two codes--are considered. Simulation results from the TREETOPS code are compared with those from the other two codes for two example systems. One system is a chain of rigid bodies; the other consists of two rigid bodies attached to a flexible base body. Since the computer codes were developed independently, consistent results serve as a verification of the correctness of all the programs. Differences in the results are discussed. Results for the two-rigid-body, one-flexible-body system are useful also as information on multi-body, flexible, pointing payload dynamics.

The dynamics and control of large flexible space structures. Part A: Discrete model and modal control

NASA Technical Reports Server (NTRS)

Bainum, P. M.; Sellappan, R.

1978-01-01

Attitude control techniques for the pointing and stabilization of very large, inherently flexible spacecraft systems were investigated. The attitude dynamics and control of a long, homogeneous flexible beam whose center of mass is assumed to follow a circular orbit was analyzed. First order effects of gravity gradient were included. A mathematical model which describes the system rotations and deflections within the orbital plane was developed by treating the beam as a number of discretized mass particles connected by massless, elastic structural elements. The uncontrolled dynamics of the system are simulated and, in addition, the effects of the control devices were considered. The concept of distributed modal control, which provides a means for controlling a system mode independently of all other modes, was examined. The effect of varying the number of modes in the model as well as the number and location of the control devices were also considered.

Hydrogen bonding in protic ionic liquids: structural correlations, vibrational spectroscopy, and rotational dynamics of liquid ethylammonium nitrate

NASA Astrophysics Data System (ADS)

Zentel, Tobias; Overbeck, Viviane; Michalik, Dirk; Kühn, Oliver; Ludwig, Ralf

2018-02-01

The properties of the hydrogen bonds in ethylammonium nitrate (EAN) are analyzed by using molecular dynamics simulations and infrared as well as nuclear magnetic resonance experiments. EAN features a flexible three-dimensional network of hydrogen bonds with moderate strengths, which makes it distinct from related triethylammonium-based ionic liquids. First, the network’s flexibility is manifested in a not very pronounced correlation of the hydrogen bond geometries, which is caused by rapid interchanges of bonding partners. The large flexibility of the network also leads to a substantial broadening of the mid-IR absorption band, with the contributions due to N-H stretching motions ranging from 2800 to 3250 cm-1. Finally, the different dynamics are also seen in the rotational correlation of the N-H bond vector, where a correlation time as short as 16.1 ps is observed.

Residence rule flexibility and descent groups dynamics shape uniparental genetic diversities in South East Asia.

PubMed

Ly, Goki; Alard, Bérénice; Laurent, Romain; Lafosse, Sophie; Toupance, Bruno; Monidarin, Chou; Diffloth, Gérard; Bourdier, Frédéric; Evrard, Olivier; Pavard, Samuel; Chaix, Raphaëlle

2018-03-01

Social organization plays a major role in shaping human population genetic diversity. In particular, matrilocal populations tend to exhibit less mitochondrial diversity than patrilocal populations, and the other way around for Y chromosome diversity. However, several studies have not replicated such findings. The objective of this study is to understand the reasons for such inconsistencies and further evaluate the influence of social organization on genetic diversity. We explored uniparental diversity patterns using mitochondrial HV1 sequences and 17 Y-linked short tandem repeats (STRs) in 12 populations (n = 619) from mainland South-East Asia exhibiting a wide range of social organizations, along with quantitative ethno-demographic information sampled at the individual level. MtDNA diversity was lower in matrilocal than in multilocal and patrilocal populations while Y chromosome diversity was similar among these social organizations. The reasons for such asymmetry at the genetic level were understood by quantifying sex-specific migration rates from our ethno-demographic data: while female migration rates varied between social organizations, male migration rates did not. This unexpected lack of difference in male migrations resulted from a higher flexibility in residence rule in patrilocal than in matrilocal populations. In addition, our data suggested an impact of clan fission process on uniparental genetic patterns. The observed lack of signature of patrilocality on Y chromosome patterns might be attributed to the higher residence flexibility in the studied patrilocal populations, thus providing a potential explanation for the apparent discrepancies between social and genetic structures. Altogether, this study highlights the need to quantify the actual residence and descent patterns to fit social to genetic structures. © 2018 Wiley Periodicals, Inc.

Experimental demonstration of the control of flexible structures

NASA Technical Reports Server (NTRS)

Schaechter, D. B.; Eldred, D. B.

1984-01-01

The Large Space Structure Technology Flexible Beam Experiment employs a pinned-free flexible beam to demonstrate such required methods as dynamic and adaptive control, as well as various control law design approaches and hardware requirements. An attempt is made to define the mechanization difficulties that may inhere in flexible structures. Attention is presently given to analytical work performed in support of the test facility's development, the final design's specifications, the control laws' synthesis, and experimental results obtained.

Acute effects of different dynamic exercises on hamstring strain risk factors.

PubMed

Chen, Che Hsiu; Xin, Ye; Lee, Kuang Wu; Lin, Ming Ju; Lin, Jiu Jenq

2018-01-01

The purpose of the study was to examine the acute effects of different dynamic exercise interventions on hamstring muscle performance. Thirty-six young men with poor hamstring flexibility were randomly assigned to three intervention groups: jogging combined with dynamic open kinetic chain stretching (DS), jogging combined with dynamic closed kinetic chain stretching (lunge with eccentric hamstring windmills, LEC), and jogging only (CON) groups. Hamstring flexibility, muscle stiffness (area under the curve, AUC), joint position sense (JPS), maximal eccentric strength (ECC), and angle of peak torque (APT) were recorded before and immediately after the exercise interventions. The results showed that the hamstring flexibility increased in DS (p < 0.001); muscle stiffness decreased in DS and was lower than jogging (p < 0.001). Moreover, ECC increased in LEC and was higher than jogging and DS (p < 0.001). APT was different among 3 groups (p < 0.001). Decreased accuracy of JPS was found in DS and jogging (p < 0.001). In conclusion, the dynamic closed kinetic chain stretching (LEC) as compared to open kinetic chain stretching (DS) or jogging group, may be an effective technique to enhance muscle performance during the pre-competition warm-up routine.

Acute effects of different dynamic exercises on hamstring strain risk factors

PubMed Central

Xin, Ye; Lee, Kuang Wu; Lin, Ming Ju

2018-01-01

The purpose of the study was to examine the acute effects of different dynamic exercise interventions on hamstring muscle performance. Thirty-six young men with poor hamstring flexibility were randomly assigned to three intervention groups: jogging combined with dynamic open kinetic chain stretching (DS), jogging combined with dynamic closed kinetic chain stretching (lunge with eccentric hamstring windmills, LEC), and jogging only (CON) groups. Hamstring flexibility, muscle stiffness (area under the curve, AUC), joint position sense (JPS), maximal eccentric strength (ECC), and angle of peak torque (APT) were recorded before and immediately after the exercise interventions. The results showed that the hamstring flexibility increased in DS (p < 0.001); muscle stiffness decreased in DS and was lower than jogging (p < 0.001). Moreover, ECC increased in LEC and was higher than jogging and DS (p < 0.001). APT was different among 3 groups (p < 0.001). Decreased accuracy of JPS was found in DS and jogging (p < 0.001). In conclusion, the dynamic closed kinetic chain stretching (LEC) as compared to open kinetic chain stretching (DS) or jogging group, may be an effective technique to enhance muscle performance during the pre-competition warm-up routine. PMID:29390001