Computer program for calculating and fitting thermodynamic functions

NASA Technical Reports Server (NTRS)

Mcbride, Bonnie J.; Gordon, Sanford

1992-01-01

A computer program is described which (1) calculates thermodynamic functions (heat capacity, enthalpy, entropy, and free energy) for several optional forms of the partition function, (2) fits these functions to empirical equations by means of a least-squares fit, and (3) calculates, as a function of temperture, heats of formation and equilibrium constants. The program provides several methods for calculating ideal gas properties. For monatomic gases, three methods are given which differ in the technique used for truncating the partition function. For diatomic and polyatomic molecules, five methods are given which differ in the corrections to the rigid-rotator harmonic-oscillator approximation. A method for estimating thermodynamic functions for some species is also given.

Constructing diabatic representations using adiabatic and approximate diabatic data--Coping with diabolical singularities.

PubMed

Zhu, Xiaolei; Yarkony, David R

2016-01-28

We have recently introduced a diabatization scheme, which simultaneously fits and diabatizes adiabatic ab initio electronic wave functions, Zhu and Yarkony J. Chem. Phys. 140, 024112 (2014). The algorithm uses derivative couplings in the defining equations for the diabatic Hamiltonian, H(d), and fits all its matrix elements simultaneously to adiabatic state data. This procedure ultimately provides an accurate, quantifiably diabatic, representation of the adiabatic electronic structure data. However, optimizing the large number of nonlinear parameters in the basis functions and adjusting the number and kind of basis functions from which the fit is built, which provide the essential flexibility, has proved challenging. In this work, we introduce a procedure that combines adiabatic state and diabatic state data to efficiently optimize the nonlinear parameters and basis function expansion. Further, we consider using direct properties based diabatizations to initialize the fitting procedure. To address this issue, we introduce a systematic method for eliminating the debilitating (diabolical) singularities in the defining equations of properties based diabatizations. We exploit the observation that if approximate diabatic data are available, the commonly used approach of fitting each matrix element of H(d) individually provides a starting point (seed) from which convergence of the full H(d) construction algorithm is rapid. The optimization of nonlinear parameters and basis functions and the elimination of debilitating singularities are, respectively, illustrated using the 1,2,3,4(1)A states of phenol and the 1,2(1)A states of NH3, states which are coupled by conical intersections.

Neutron Multiplicity: LANL W Covariance Matrix for Curve Fitting

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

Wendelberger, James G.

2016-12-08

In neutron multiplicity counting one may fit a curve by minimizing an objective function, χmore » $$2\\atop{n}$$. The objective function includes the inverse of an n by n matrix of covariances, W. The inverse of the W matrix has a closed form solution. In addition W -1 is a tri-diagonal matrix. The closed form and tridiagonal nature allows for a simpler expression of the objective function χ$$2\\atop{n}$$. Minimization of this simpler expression will provide the optimal parameters for the fitted curve.« less

Nonlinear Curve-Fitting Program

NASA Technical Reports Server (NTRS)

Everhart, Joel L.; Badavi, Forooz F.

1989-01-01

Nonlinear optimization algorithm helps in finding best-fit curve. Nonlinear Curve Fitting Program, NLINEAR, interactive curve-fitting routine based on description of quadratic expansion of X(sup 2) statistic. Utilizes nonlinear optimization algorithm calculating best statistically weighted values of parameters of fitting function and X(sup 2) minimized. Provides user with such statistical information as goodness of fit and estimated values of parameters producing highest degree of correlation between experimental data and mathematical model. Written in FORTRAN 77.

Calibration data Analysis Package (CAP): An IDL based widget application for analysis of X-ray calibration data

NASA Astrophysics Data System (ADS)

Vaishali, S.; Narendranath, S.; Sreekumar, P.

An IDL (interactive data language) based widget application developed for the calibration of C1XS (Narendranath et al., 2010) instrument on Chandrayaan-1 is modified to provide a generic package for the analysis of data from x-ray detectors. The package supports files in ascii as well as FITS format. Data can be fitted with a list of inbuilt functions to derive the spectral redistribution function (SRF). We have incorporated functions such as `HYPERMET' (Philips & Marlow 1976) including non Gaussian components in the SRF such as low energy tail, low energy shelf and escape peak. In addition users can incorporate additional models which may be required to model detector specific features. Spectral fits use a routine `mpfit' which uses Leven-Marquardt least squares fitting method. The SRF derived from this tool can be fed into an accompanying program to generate a redistribution matrix file (RMF) compatible with the X-ray spectral analysis package XSPEC. The tool provides a user friendly interface of help to beginners and also provides transparency and advanced features for experts.

Normative functional fitness standards and trends of Portuguese older adults: cross-cultural comparisons.

PubMed

Marques, Elisa A; Baptista, Fátima; Santos, Rute; Vale, Susana; Santos, Diana A; Silva, Analiza M; Mota, Jorge; Sardinha, Luís B

2014-01-01

This cross-sectional study was designed to develop normative functional fitness standards for the Portuguese older adults, to analyze age and gender patterns of decline, to compare the fitness level of Portuguese older adults with that of older adults in other countries, and to evaluate the fitness level of Portuguese older adults relative to recently published criterion fitness standards associated with maintaining physical independence. A sample of 4,712 independent-living older adults, age 65-103 yr, was evaluated using the Senior Fitness Test battery. Age-group normative fitness scores are reported for the 10th, 25th, 50th, 75th, and 90th percentiles. Results indicate that both women and men experience age-related losses in all components of functional fitness, with their rate of decline being greater than that observed in other populations, a trend which may cause Portuguese older adults to be at greater risk for loss of independence in later years. These newly established normative standards make it possible to assess individual fitness level and provide a basis for implementing population-wide health strategies to counteract early loss of independence.

A simple modification of TG-43 based brachytherapy dosimetry with improved fitting functions: application to the selectSeed source.

PubMed

Juan-Senabre, Xavier J; Porras, Ignacio; Lallena, Antonio M

2013-06-01

A variation of TG-43 protocol for seeds with cylindrical symmetry aiming at a better description of the radial and anisotropy functions is proposed. The TG-43 two dimensional formalism is modified by introducing a new anisotropy function. Also new fitting functions that permit a more robust description of the radial and anisotropy functions than usual polynomials are studied. The relationship between the new anisotropy function and the anisotropy factor included in the one-dimensional TG-43 formalism is analyzed. The new formalism is tested for the (125)I Nucletron selectSeed brachytherapy source, using Monte Carlo simulations performed with PENELOPE. The goodness of the new parameterizations is discussed. The results obtained indicate that precise fits can be achieved, with a better description than that provided by previous parameterizations. Special care has been taken in the description and fitting of the anisotropy factor near the source. The modified formalism shows advantages with respect to the usual one in the description of the anisotropy functions. The new parameterizations obtained can be easily implemented in the clinical planning calculation systems, provided that the ratio between geometry factors is also modified according to the new dose rate expression. Copyright © 2012 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Signal detection theory and vestibular perception: III. Estimating unbiased fit parameters for psychometric functions.

PubMed

Chaudhuri, Shomesh E; Merfeld, Daniel M

2013-03-01

Psychophysics generally relies on estimating a subject's ability to perform a specific task as a function of an observed stimulus. For threshold studies, the fitted functions are called psychometric functions. While fitting psychometric functions to data acquired using adaptive sampling procedures (e.g., "staircase" procedures), investigators have encountered a bias in the spread ("slope" or "threshold") parameter that has been attributed to the serial dependency of the adaptive data. Using simulations, we confirm this bias for cumulative Gaussian parametric maximum likelihood fits on data collected via adaptive sampling procedures, and then present a bias-reduced maximum likelihood fit that substantially reduces the bias without reducing the precision of the spread parameter estimate and without reducing the accuracy or precision of the other fit parameters. As a separate topic, we explain how to implement this bias reduction technique using generalized linear model fits as well as other numeric maximum likelihood techniques such as the Nelder-Mead simplex. We then provide a comparison of the iterative bootstrap and observed information matrix techniques for estimating parameter fit variance from adaptive sampling procedure data sets. The iterative bootstrap technique is shown to be slightly more accurate; however, the observed information technique executes in a small fraction (0.005 %) of the time required by the iterative bootstrap technique, which is an advantage when a real-time estimate of parameter fit variance is required.

Cardiorespiratory Fitness and Motor Skills in Relation to Cognition and Academic Performance in Children – A Review

PubMed Central

Haapala, Eero A.

2013-01-01

Different elements of physical fitness in children have shown a declining trend during the past few decades. Cardiorespiratory fitness and motor skills have been associated with cognition, but the magnitude of this association remains unknown. The purpose of this review is to provide an overview of the relationship of cardiorespiratory fitness and motor skills with cognitive functions and academic performance in children up to 13 years of age. Cross-sectional studies suggest that children with higher cardiorespiratory fitness have more efficient cognitive processing at the neuroelectric level, as well as larger hippocampal and basal ganglia volumes, compared to children with lower cardiorespiratory fitness. Higher cardiorespiratory fitness has been associated with better inhibitory control in tasks requiring rigorous attention allocation. Better motor skills have been related to more efficient cognitive functions including inhibitory control and working memory. Higher cardiorespiratory fitness and better motor skills have also been associated with better academic performance. Furthermore, none of the studies on cardiorespiratory fitness have revealed independent associations with cognitive functions by controlling for motor skills. Studies concerning the relationship between motor skills and cognitive functions also did not consider cardiorespiratory fitness in the analyses. The results of this review suggest that high levels of cardiorespiratory fitness and motor skills may be beneficial for cognitive development and academic performance but the evidence relies mainly on cross-sectional studies. PMID:23717355

NLINEAR - NONLINEAR CURVE FITTING PROGRAM

NASA Technical Reports Server (NTRS)

Everhart, J. L.

1994-01-01

A common method for fitting data is a least-squares fit. In the least-squares method, a user-specified fitting function is utilized in such a way as to minimize the sum of the squares of distances between the data points and the fitting curve. The Nonlinear Curve Fitting Program, NLINEAR, is an interactive curve fitting routine based on a description of the quadratic expansion of the chi-squared statistic. NLINEAR utilizes a nonlinear optimization algorithm that calculates the best statistically weighted values of the parameters of the fitting function and the chi-square that is to be minimized. The inputs to the program are the mathematical form of the fitting function and the initial values of the parameters to be estimated. This approach provides the user with statistical information such as goodness of fit and estimated values of parameters that produce the highest degree of correlation between the experimental data and the mathematical model. In the mathematical formulation of the algorithm, the Taylor expansion of chi-square is first introduced, and justification for retaining only the first term are presented. From the expansion, a set of n simultaneous linear equations are derived, which are solved by matrix algebra. To achieve convergence, the algorithm requires meaningful initial estimates for the parameters of the fitting function. NLINEAR is written in Fortran 77 for execution on a CDC Cyber 750 under NOS 2.3. It has a central memory requirement of 5K 60 bit words. Optionally, graphical output of the fitting function can be plotted. Tektronix PLOT-10 routines are required for graphics. NLINEAR was developed in 1987.

Constructing diabatic representations using adiabatic and approximate diabatic data – Coping with diabolical singularities

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

Zhu, Xiaolei, E-mail: virtualzx@gmail.com; Yarkony, David R., E-mail: yarkony@jhu.edu

2016-01-28

We have recently introduced a diabatization scheme, which simultaneously fits and diabatizes adiabatic ab initio electronic wave functions, Zhu and Yarkony J. Chem. Phys. 140, 024112 (2014). The algorithm uses derivative couplings in the defining equations for the diabatic Hamiltonian, H{sup d}, and fits all its matrix elements simultaneously to adiabatic state data. This procedure ultimately provides an accurate, quantifiably diabatic, representation of the adiabatic electronic structure data. However, optimizing the large number of nonlinear parameters in the basis functions and adjusting the number and kind of basis functions from which the fit is built, which provide the essential flexibility,more » has proved challenging. In this work, we introduce a procedure that combines adiabatic state and diabatic state data to efficiently optimize the nonlinear parameters and basis function expansion. Further, we consider using direct properties based diabatizations to initialize the fitting procedure. To address this issue, we introduce a systematic method for eliminating the debilitating (diabolical) singularities in the defining equations of properties based diabatizations. We exploit the observation that if approximate diabatic data are available, the commonly used approach of fitting each matrix element of H{sup d} individually provides a starting point (seed) from which convergence of the full H{sup d} construction algorithm is rapid. The optimization of nonlinear parameters and basis functions and the elimination of debilitating singularities are, respectively, illustrated using the 1,2,3,4{sup 1}A states of phenol and the 1,2{sup 1}A states of NH{sub 3}, states which are coupled by conical intersections.« less

The Gaussian-Lorentzian Sum, Product, and Convolution (Voigt) functions in the context of peak fitting X-ray photoelectron spectroscopy (XPS) narrow scans

NASA Astrophysics Data System (ADS)

Jain, Varun; Biesinger, Mark C.; Linford, Matthew R.

2018-07-01

X-ray photoelectron spectroscopy (XPS) is arguably the most important vacuum technique for surface chemical analysis, and peak fitting is an indispensable part of XPS data analysis. Functions that have been widely explored and used in XPS peak fitting include the Gaussian, Lorentzian, Gaussian-Lorentzian sum (GLS), Gaussian-Lorentzian product (GLP), and Voigt functions, where the Voigt function is a convolution of a Gaussian and a Lorentzian function. In this article we discuss these functions from a graphical perspective. Arguments based on convolution and the Central Limit Theorem are made to justify the use of functions that are intermediate between pure Gaussians and pure Lorentzians in XPS peak fitting. Mathematical forms for the GLS and GLP functions are presented with a mixing parameter m. Plots are shown for GLS and GLP functions with mixing parameters ranging from 0 to 1. There are fundamental differences between the GLS and GLP functions. The GLS function better follows the 'wings' of the Lorentzian, while these 'wings' are suppressed in the GLP. That is, these two functions are not interchangeable. The GLS and GLP functions are compared to the Voigt function, where the GLS is shown to be a decent approximation of it. Practically, both the GLS and the GLP functions can be useful for XPS peak fitting. Examples of the uses of these functions are provided herein.

Towards an informative mutant phenotype for every bacterial gene

DOE PAGES

Deutschbauer, Adam; Price, Morgan N.; Wetmore, Kelly M.; ...

2014-08-11

Mutant phenotypes provide strong clues to the functions of the underlying genes and could allow annotation of the millions of sequenced yet uncharacterized bacterial genes. However, it is not known how many genes have a phenotype under laboratory conditions, how many phenotypes are biologically interpretable for predicting gene function, and what experimental conditions are optimal to maximize the number of genes with a phenotype. To address these issues, we measured the mutant fitness of 1,586 genes of the ethanol-producing bacterium Zymomonas mobilis ZM4 across 492 diverse experiments and found statistically significant phenotypes for 89% of all assayed genes. Thus, inmore » Z. mobilis, most genes have a functional consequence under laboratory conditions. We demonstrate that 41% of Z. mobilis genes have both a strong phenotype and a similar fitness pattern (cofitness) to another gene, and are therefore good candidates for functional annotation using mutant fitness. Among 502 poorly characterized Z. mobilis genes, we identified a significant cofitness relationship for 174. For 57 of these genes without a specific functional annotation, we found additional evidence to support the biological significance of these gene-gene associations, and in 33 instances, we were able to predict specific physiological or biochemical roles for the poorly characterized genes. Last, we identified a set of 79 diverse mutant fitness experiments in Z. mobilis that are nearly as biologically informative as the entire set of 492 experiments. Therefore, our work provides a blueprint for the functional annotation of diverse bacteria using mutant fitness.« less

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

Deutschbauer, Adam; Price, Morgan N.; Wetmore, Kelly M.

Mutant phenotypes provide strong clues to the functions of the underlying genes and could allow annotation of the millions of sequenced yet uncharacterized bacterial genes. However, it is not known how many genes have a phenotype under laboratory conditions, how many phenotypes are biologically interpretable for predicting gene function, and what experimental conditions are optimal to maximize the number of genes with a phenotype. To address these issues, we measured the mutant fitness of 1,586 genes of the ethanol-producing bacterium Zymomonas mobilis ZM4 across 492 diverse experiments and found statistically significant phenotypes for 89% of all assayed genes. Thus, inmore » Z. mobilis, most genes have a functional consequence under laboratory conditions. We demonstrate that 41% of Z. mobilis genes have both a strong phenotype and a similar fitness pattern (cofitness) to another gene, and are therefore good candidates for functional annotation using mutant fitness. Among 502 poorly characterized Z. mobilis genes, we identified a significant cofitness relationship for 174. For 57 of these genes without a specific functional annotation, we found additional evidence to support the biological significance of these gene-gene associations, and in 33 instances, we were able to predict specific physiological or biochemical roles for the poorly characterized genes. Last, we identified a set of 79 diverse mutant fitness experiments in Z. mobilis that are nearly as biologically informative as the entire set of 492 experiments. Therefore, our work provides a blueprint for the functional annotation of diverse bacteria using mutant fitness.« less

Pattern of Change in Prolonged Exposure and Cognitive-Processing Therapy for Female Rape Victims With Posttraumatic Stress Disorder

PubMed Central

Nishith, Pallavi; Resick, Patricia A.; Griffin, Michael G.

2010-01-01

Curve estimation techniques were used to identify the pattern of therapeutic change in female rape victims with posttraumatic stress disorder (PTSD). Within-session data on the Posttraumatic Stress Disorder Symptom Scale were obtained, in alternate therapy sessions, on 171 women. The final sample of treatment completers included 54 prolonged exposure (PE) and 54 cognitive-processing therapy (CPT) completers. For both PE and CPT, a quadratic function provided the best fit for the total PTSD, reexperiencing, and arousal scores. However, a difference in the line of best fit was observed for the avoidance symptoms. Although a quadratic function still provided a better fit for the PE avoidance, a linear function was more parsimonious in explaining the CPT avoidance variance. Implications of the findings are discussed. PMID:12182271

An Empirical Fitting Method for Type Ia Supernova Light Curves: A Case Study of SN 2011fe

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

Zheng, WeiKang; Filippenko, Alexei V., E-mail: zwk@astro.berkeley.edu

We present a new empirical fitting method for the optical light curves of Type Ia supernovae (SNe Ia). We find that a variant broken-power-law function provides a good fit, with the simple assumption that the optical emission is approximately the blackbody emission of the expanding fireball. This function is mathematically analytic and is derived directly from the photospheric velocity evolution. When deriving the function, we assume that both the blackbody temperature and photospheric velocity are constant, but the final function is able to accommodate these changes during the fitting procedure. Applying it to the case study of SN 2011fe givesmore » a surprisingly good fit that can describe the light curves from the first-light time to a few weeks after peak brightness, as well as over a large range of fluxes (∼5 mag, and even ∼7 mag in the g band). Since SNe Ia share similar light-curve shapes, this fitting method has the potential to fit most other SNe Ia and characterize their properties in large statistical samples such as those already gathered and in the near future as new facilities become available.« less

Recalculating the quasar luminosity function of the extended Baryon Oscillation Spectroscopic Survey

NASA Astrophysics Data System (ADS)

Caditz, David M.

2017-12-01

Aims: The extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey provides a uniform sample of over 13 000 variability selected quasi-stellar objects (QSOs) in the redshift range 0.68

On the log-normality of historical magnetic-storm intensity statistics: implications for extreme-event probabilities

USGS Publications Warehouse

Love, Jeffrey J.; Rigler, E. Joshua; Pulkkinen, Antti; Riley, Pete

2015-01-01

An examination is made of the hypothesis that the statistics of magnetic-storm-maximum intensities are the realization of a log-normal stochastic process. Weighted least-squares and maximum-likelihood methods are used to fit log-normal functions to −Dst storm-time maxima for years 1957-2012; bootstrap analysis is used to established confidence limits on forecasts. Both methods provide fits that are reasonably consistent with the data; both methods also provide fits that are superior to those that can be made with a power-law function. In general, the maximum-likelihood method provides forecasts having tighter confidence intervals than those provided by weighted least-squares. From extrapolation of maximum-likelihood fits: a magnetic storm with intensity exceeding that of the 1859 Carrington event, −Dst≥850 nT, occurs about 1.13 times per century and a wide 95% confidence interval of [0.42,2.41] times per century; a 100-yr magnetic storm is identified as having a −Dst≥880 nT (greater than Carrington) but a wide 95% confidence interval of [490,1187] nT.

Typology of person-environment fit constellations: a platform addressing accessibility problems in the built environment for people with functional limitations.

PubMed

Slaug, Björn; Schilling, Oliver; Iwarsson, Susanne; Carlsson, Gunilla

2015-09-02

Making the built environment accessible for all regardless of functional capacity is an important goal for public health efforts. Considerable impediments to achieving this goal suggest the need for valid measurements of acccessibility and for greater attention to the complexity of person-environment fit issues. To address these needs, this study aimed to provide a methodological platform, useful for further research and instrument development within accessibility research. This was accomplished by the construction of a typology of problematic person-environment fit constellations, utilizing an existing methodology developed to assess and analyze accessibility problems in the built environment. By means of qualitative review and statistical methods we classified the person-environment fit components covered by an existing application which targets housing accessibility: the Housing Enabler (HE) instrument. The International Classification of Functioning, Disability and Health (ICF) was used as a conceptual framework. Qualitative classification principles were based on conceptual similarities and for quantitative analysis of similarities, Principal Component Analysis was carried out. We present a typology of problematic person-environment fit constellations classified along three dimensions: 1) accessibility problem range and severity 2) aspects of functioning 3) environmental context. As a result of the classification of the HE components, 48 typical person-environment fit constellations were recognised. The main contribution of this study is the proposed typology of person-environment fit constellations. The typology provides a methodological platform for the identification and quantification of problematic person-environment fit constellations. Its link to the globally accepted ICF classification system facilitates communication within the scientific and health care practice communities. The typology also highlights how relations between aspects of functioning and physical environmental barriers generate typical accessibility problems, and thereby furnishes a reference point for research oriented to how the built environment may be designed to be supportive for activity, participation and health.

Simulation and fitting of complex reaction network TPR: The key is the objective function

DOE PAGES

Savara, Aditya Ashi

2016-07-07

In this research, a method has been developed for finding improved fits during simulation and fitting of data from complex reaction network temperature programmed reactions (CRN-TPR). It was found that simulation and fitting of CRN-TPR presents additional challenges relative to simulation and fitting of simpler TPR systems. The method used here can enable checking the plausibility of proposed chemical mechanisms and kinetic models. The most important finding was that when choosing an objective function, use of an objective function that is based on integrated production provides more utility in finding improved fits when compared to an objective function based onmore » the rate of production. The response surface produced by using the integrated production is monotonic, suppresses effects from experimental noise, requires fewer points to capture the response behavior, and can be simulated numerically with smaller errors. For CRN-TPR, there is increased importance (relative to simple reaction network TPR) in resolving of peaks prior to fitting, as well as from weighting of experimental data points. Using an implicit ordinary differential equation solver was found to be inadequate for simulating CRN-TPR. Lastly, the method employed here was capable of attaining improved fits in simulation and fitting of CRN-TPR when starting with a postulated mechanism and physically realistic initial guesses for the kinetic parameters.« less

SPLICER - A GENETIC ALGORITHM TOOL FOR SEARCH AND OPTIMIZATION, VERSION 1.0 (MACINTOSH VERSION)

NASA Technical Reports Server (NTRS)

Wang, L.

1994-01-01

SPLICER is a genetic algorithm tool which can be used to solve search and optimization problems. Genetic algorithms are adaptive search procedures (i.e. problem solving methods) based loosely on the processes of natural selection and Darwinian "survival of the fittest." SPLICER provides the underlying framework and structure for building a genetic algorithm application. These algorithms apply genetically-inspired operators to populations of potential solutions in an iterative fashion, creating new populations while searching for an optimal or near-optimal solution to the problem at hand. SPLICER 1.0 was created using a modular architecture that includes a Genetic Algorithm Kernel, interchangeable Representation Libraries, Fitness Modules and User Interface Libraries, and well-defined interfaces between these components. The architecture supports portability, flexibility, and extensibility. SPLICER comes with all source code and several examples. For instance, a "traveling salesperson" example searches for the minimum distance through a number of cities visiting each city only once. Stand-alone SPLICER applications can be used without any programming knowledge. However, to fully utilize SPLICER within new problem domains, familiarity with C language programming is essential. SPLICER's genetic algorithm (GA) kernel was developed independent of representation (i.e. problem encoding), fitness function or user interface type. The GA kernel comprises all functions necessary for the manipulation of populations. These functions include the creation of populations and population members, the iterative population model, fitness scaling, parent selection and sampling, and the generation of population statistics. In addition, miscellaneous functions are included in the kernel (e.g., random number generators). Different problem-encoding schemes and functions are defined and stored in interchangeable representation libraries. This allows the GA kernel to be used with any representation scheme. The SPLICER tool provides representation libraries for binary strings and for permutations. These libraries contain functions for the definition, creation, and decoding of genetic strings, as well as multiple crossover and mutation operators. Furthermore, the SPLICER tool defines the appropriate interfaces to allow users to create new representation libraries. Fitness modules are the only component of the SPLICER system a user will normally need to create or alter to solve a particular problem. Fitness functions are defined and stored in interchangeable fitness modules which must be created using C language. Within a fitness module, a user can create a fitness (or scoring) function, set the initial values for various SPLICER control parameters (e.g., population size), create a function which graphically displays the best solutions as they are found, and provide descriptive information about the problem. The tool comes with several example fitness modules, while the process of developing a fitness module is fully discussed in the accompanying documentation. The user interface is event-driven and provides graphic output in windows. SPLICER is written in Think C for Apple Macintosh computers running System 6.0.3 or later and Sun series workstations running SunOS. The UNIX version is easily ported to other UNIX platforms and requires MIT's X Window System, Version 11 Revision 4 or 5, MIT's Athena Widget Set, and the Xw Widget Set. Example executables and source code are included for each machine version. The standard distribution media for the Macintosh version is a set of three 3.5 inch Macintosh format diskettes. The standard distribution medium for the UNIX version is a .25 inch streaming magnetic tape cartridge in UNIX tar format. For the UNIX version, alternate distribution media and formats are available upon request. SPLICER was developed in 1991.

Brain activation during dual-task processing is associated with cardiorespiratory fitness and performance in older adults

PubMed Central

Wong, Chelsea N.; Chaddock-Heyman, Laura; Voss, Michelle W.; Burzynska, Agnieszka Z.; Basak, Chandramallika; Erickson, Kirk I.; Prakash, Ruchika S.; Szabo-Reed, Amanda N.; Phillips, Siobhan M.; Wojcicki, Thomas; Mailey, Emily L.; McAuley, Edward; Kramer, Arthur F.

2015-01-01

Higher cardiorespiratory fitness is associated with better cognitive performance and enhanced brain activation. Yet, the extent to which cardiorespiratory fitness-related brain activation is associated with better cognitive performance is not well understood. In this cross-sectional study, we examined whether the association between cardiorespiratory fitness and executive function was mediated by greater prefrontal cortex activation in healthy older adults. Brain activation was measured during dual-task performance with functional magnetic resonance imaging in a sample of 128 healthy older adults (59–80 years). Higher cardiorespiratory fitness was associated with greater activation during dual-task processing in several brain areas including the anterior cingulate and supplementary motor cortex (ACC/SMA), thalamus and basal ganglia, right motor/somatosensory cortex and middle frontal gyrus, and left somatosensory cortex, controlling for age, sex, education, and gray matter volume. Of these regions, greater ACC/SMA activation mediated the association between cardiorespiratory fitness and dual-task performance. We provide novel evidence that cardiorespiratory fitness may support cognitive performance by facilitating brain activation in a core region critical for executive function. PMID:26321949

Computation and analysis of the transverse current autocorrelation function, Ct(k,t), for small wave vectors: A molecular-dynamics study for a Lennard-Jones fluid

NASA Astrophysics Data System (ADS)

Vogelsang, R.; Hoheisel, C.

1987-02-01

Molecular-dynamics (MD) calculations are reported for three thermodynamic states of a Lennard-Jones fluid. Systems of 2048 particles and 105 integration steps were used. The transverse current autocorrelation function, Ct(k,t), has been determined for wave vectors of the range 0.5<||k||σ<1.5. Ct(k,t) was fitted by hydrodynamic-type functions. The fits returned k-dependent decay times and shear viscosities which showed a systematic behavior as a function of k. Extrapolation to the hydrodynamic region at k=0 gave shear viscosity coefficients in good agreement with direct Green-Kubo results obtained in previous work. The two-exponential model fit for the memory function proposed by other authors does not provide a reasonable description of the MD results, as the fit parameters show no systematic wave-vector dependence, although the Ct(k,t) functions are somewhat better fitted. Similarly, the semiempirical interpolation formula for the decay time based on the viscoelastic concept proposed by Akcasu and Daniels fails to reproduce the correct k dependence for the wavelength range investigated herein.

Cole-Davidson dynamics of simple chain models.

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

Dotson, Taylor C.; McCoy, John Dwane; Adolf, Douglas Brian

2008-10-01

Rotational relaxation functions of the end-to-end vector of short, freely jointed and freely rotating chains were determined from molecular dynamics simulations. The associated response functions were obtained from the one-sided Fourier transform of the relaxation functions. The Cole-Davidson function was used to fit the response functions with extensive use being made of Cole-Cole plots in the fitting procedure. For the systems studied, the Cole-Davidson function provided remarkably accurate fits [as compared to the transform of the Kohlrausch-Williams-Watts (KWW) function]. The only appreciable deviations from the simulation results were in the high frequency limit and were due to ballistic or freemore » rotation effects. The accuracy of the Cole-Davidson function appears to be the result of the transition in the time domain from stretched exponential behavior at intermediate time to single exponential behavior at long time. Such a transition can be explained in terms of a distribution of relaxation times with a well-defined longest relaxation time. Since the Cole-Davidson distribution has a sharp cutoff in relaxation time (while the KWW function does not), it makes sense that the Cole-Davidson would provide a better frequency-domain description of the associated response function than the KWW function does.« less

Concave utility, transaction costs, and risk in measuring discounting of delayed rewards.

PubMed

Kirby, Kris N; Santiesteban, Mariana

2003-01-01

Research has consistently found that the decline in the present values of delayed rewards as delay increases is better fit by hyperbolic than by exponential delay-discounting functions. However, concave utility, transaction costs, and risk each could produce hyperbolic-looking data, even when the underlying discounting function is exponential. In Experiments 1 (N = 45) and 2 (N = 103), participants placed bids indicating their present values of real future monetary rewards in computer-based 2nd-price auctions. Both experiments suggest that utility is not sufficiently concave to account for the superior fit of hyperbolic functions. Experiment 2 provided no evidence that the effects of transaction costs and risk are large enough to account for the superior fit of hyperbolic functions.

Fitting a function to time-dependent ensemble averaged data.

PubMed

Fogelmark, Karl; Lomholt, Michael A; Irbäck, Anders; Ambjörnsson, Tobias

2018-05-03

Time-dependent ensemble averages, i.e., trajectory-based averages of some observable, are of importance in many fields of science. A crucial objective when interpreting such data is to fit these averages (for instance, squared displacements) with a function and extract parameters (such as diffusion constants). A commonly overlooked challenge in such function fitting procedures is that fluctuations around mean values, by construction, exhibit temporal correlations. We show that the only available general purpose function fitting methods, correlated chi-square method and the weighted least squares method (which neglects correlation), fail at either robust parameter estimation or accurate error estimation. We remedy this by deriving a new closed-form error estimation formula for weighted least square fitting. The new formula uses the full covariance matrix, i.e., rigorously includes temporal correlations, but is free of the robustness issues, inherent to the correlated chi-square method. We demonstrate its accuracy in four examples of importance in many fields: Brownian motion, damped harmonic oscillation, fractional Brownian motion and continuous time random walks. We also successfully apply our method, weighted least squares including correlation in error estimation (WLS-ICE), to particle tracking data. The WLS-ICE method is applicable to arbitrary fit functions, and we provide a publically available WLS-ICE software.

Systematic errors in transport calculations of shear viscosity using the Green-Kubo formalism

NASA Astrophysics Data System (ADS)

Rose, J. B.; Torres-Rincon, J. M.; Oliinychenko, D.; Schäfer, A.; Petersen, H.

2018-05-01

The purpose of this study is to provide a reproducible framework in the use of the Green-Kubo formalism to extract transport coefficients. More specifically, in the case of shear viscosity, we investigate the limitations and technical details of fitting the auto-correlation function to a decaying exponential. This fitting procedure is found to be applicable for systems interacting both through constant and energy-dependent cross-sections, although this is only true for sufficiently dilute systems in the latter case. We find that the optimal fit technique consists in simultaneously fixing the intercept of the correlation function and use a fitting interval constrained by the relative error on the correlation function. The formalism is then applied to the full hadron gas, for which we obtain the shear viscosity to entropy ratio.

Effects of virtual reality exercise for Korean adults with schizophrenia in a closed ward.

PubMed

Jo, Garam; Rossow-Kimball, Brenda; Park, Gwitaek; Lee, Yongho

2018-02-01

The purpose of this study was to examine the effects of virtual reality exercise (VRE) using Nintendo Wii-Fit on physical fitness of Korean adults with schizophrenia living in a mental health facility located in South Korea. Two male participants diagnosed with schizophrenia, ages 53 and 61, were recruited and selected for inclusion in this study. The intervention using the Nintendo Wii-Fit consisted of 35-min sessions, 3 times per week for 8 weeks and was facilitated by the primary researcher and two graduate students. The senior fitness test and 10-m walking test were used to measure the physical functioning, specifically, physical fitness and mobility, of the participants. The study was divided into three phases using an A-B-A single-subject design and involved multiple repeated measures of functional physical fitness. Both participants were evaluated each week for the duration of 18 weeks. Both participants exhibited measureable improvement in some of the physical fitness measures, but not in the mobility. These results thus provide preliminary evidence to support the use of VRE to improve physical function for Korean adults with schizophrenia as an alternative exercise regimen to the conventional exercise.

Fitting model-based psychometric functions to simultaneity and temporal-order judgment data: MATLAB and R routines.

PubMed

Alcalá-Quintana, Rocío; García-Pérez, Miguel A

2013-12-01

Research on temporal-order perception uses temporal-order judgment (TOJ) tasks or synchrony judgment (SJ) tasks in their binary SJ2 or ternary SJ3 variants. In all cases, two stimuli are presented with some temporal delay, and observers judge the order of presentation. Arbitrary psychometric functions are typically fitted to obtain performance measures such as sensitivity or the point of subjective simultaneity, but the parameters of these functions are uninterpretable. We describe routines in MATLAB and R that fit model-based functions whose parameters are interpretable in terms of the processes underlying temporal-order and simultaneity judgments and responses. These functions arise from an independent-channels model assuming arrival latencies with exponential distributions and a trichotomous decision space. Different routines fit data separately for SJ2, SJ3, and TOJ tasks, jointly for any two tasks, or also jointly for the three tasks (for common cases in which two or even the three tasks were used with the same stimuli and participants). Additional routines provide bootstrap p-values and confidence intervals for estimated parameters. A further routine is included that obtains performance measures from the fitted functions. An R package for Windows and source code of the MATLAB and R routines are available as Supplementary Files.

Acquired Phototrophy through Retention of Functional Chloroplasts Increases Growth Efficiency of the Sea Slug Elysia viridis

PubMed Central

Baumgartner, Finn A.; Pavia, Henrik; Toth, Gunilla B.

2015-01-01

Photosynthesis is a fundamental process sustaining heterotrophic organisms at all trophic levels. Some mixotrophs can retain functional chloroplasts from food (kleptoplasty), and it is hypothesized that carbon acquired through kleptoplasty may enhance trophic energy transfer through increased host growth efficiency. Sacoglossan sea slugs are the only known metazoans capable of kleptoplasty, but the relative fitness contributions of heterotrophy through grazing, and phototrophy via kleptoplasts, are not well understood. Fitness benefits (i.e. increased survival or growth) of kleptoplasty in sacoglossans are commonly studied in ecologically unrealistic conditions under extended periods of complete darkness and/or starvation. We compared the growth efficiency of the sacoglossan Elysia viridis with access to algal diets providing kleptoplasts of differing functionality under ecologically relevant light conditions. Individuals fed Codium fragile, which provide highly functional kleptoplasts, nearly doubled their growth efficiency under high compared to low light. In contrast, individuals fed Cladophora rupestris, which provided kleptoplasts of limited functionality, showed no difference in growth efficiency between light treatments. Slugs feeding on Codium, but not on Cladophora, showed higher relative electron transport rates (rETR) in high compared to low light. Furthermore, there were no differences in the consumption rates of the slugs between different light treatments, and only small differences in nutritional traits of algal diets, indicating that the increased growth efficiency of E. viridis feeding on Codium was due to retention of functional kleptoplasts. Our results show that functional kleptoplasts from Codium can provide sacoglossan sea slugs with fitness advantages through photosynthesis. PMID:25830355

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

Wang, Hesheng, E-mail: hesheng@umich.edu; Feng, Mary; Jackson, Andrew

Purpose: To develop a local and global function model in the liver based on regional and organ function measurements to support individualized adaptive radiation therapy (RT). Methods and Materials: A local and global model for liver function was developed to include both functional volume and the effect of functional variation of subunits. Adopting the assumption of parallel architecture in the liver, the global function was composed of a sum of local function probabilities of subunits, varying between 0 and 1. The model was fit to 59 datasets of liver regional and organ function measures from 23 patients obtained before, during, andmore » 1 month after RT. The local function probabilities of subunits were modeled by a sigmoid function in relating to MRI-derived portal venous perfusion values. The global function was fitted to a logarithm of an indocyanine green retention rate at 15 minutes (an overall liver function measure). Cross-validation was performed by leave-m-out tests. The model was further evaluated by fitting to the data divided according to whether the patients had hepatocellular carcinoma (HCC) or not. Results: The liver function model showed that (1) a perfusion value of 68.6 mL/(100 g · min) yielded a local function probability of 0.5; (2) the probability reached 0.9 at a perfusion value of 98 mL/(100 g · min); and (3) at a probability of 0.03 [corresponding perfusion of 38 mL/(100 g · min)] or lower, the contribution to global function was lost. Cross-validations showed that the model parameters were stable. The model fitted to the data from the patients with HCC indicated that the same amount of portal venous perfusion was translated into less local function probability than in the patients with non-HCC tumors. Conclusions: The developed liver function model could provide a means to better assess individual and regional dose-responses of hepatic functions, and provide guidance for individualized treatment planning of RT.« less

Cardiorespiratory Fitness and Attentional Control in the Aging Brain

PubMed Central

Prakash, Ruchika Shaurya; Voss, Michelle W.; Erickson, Kirk I.; Lewis, Jason M.; Chaddock, Laura; Malkowski, Edward; Alves, Heloisa; Kim, Jennifer; Szabo, Amanda; White, Siobhan M.; Wójcicki, Thomas R.; Klamm, Emily L.; McAuley, Edward; Kramer, Arthur F.

2011-01-01

A growing body of literature provides evidence for the prophylactic influence of cardiorespiratory fitness on cognitive decline in older adults. This study examined the association between cardiorespiratory fitness and recruitment of the neural circuits involved in an attentional control task in a group of healthy older adults. Employing a version of the Stroop task, we examined whether higher levels of cardiorespiratory fitness were associated with an increase in activation in cortical regions responsible for imposing attentional control along with an up-regulation of activity in sensory brain regions that process task-relevant representations. Higher fitness levels were associated with better behavioral performance and an increase in the recruitment of prefrontal and parietal cortices in the most challenging condition, thus providing evidence that cardiorespiratory fitness is associated with an increase in the recruitment of the anterior processing regions. There was a top-down modulation of extrastriate visual areas that process both task-relevant and task-irrelevant attributes relative to the baseline. However, fitness was not associated with differential activation in the posterior processing regions, suggesting that fitness enhances attentional function by primarily influencing the neural circuitry of anterior cortical regions. This study provides novel evidence of a differential association of fitness with anterior and posterior brain regions, shedding further light onto the neural changes accompanying cardiorespiratory fitness. PMID:21267428

Co-evolution for Problem Simplification

NASA Technical Reports Server (NTRS)

Haith, Gary L.; Lohn, Jason D.; Cplombano, Silvano P.; Stassinopoulos, Dimitris

1999-01-01

This paper explores a co-evolutionary approach applicable to difficult problems with limited failure/success performance feedback. Like familiar "predator-prey" frameworks this algorithm evolves two populations of individuals - the solutions (predators) and the problems (prey). The approach extends previous work by rewarding only the problems that match their difficulty to the level of solut,ion competence. In complex problem domains with limited feedback, this "tractability constraint" helps provide an adaptive fitness gradient that, effectively differentiates the candidate solutions. The algorithm generates selective pressure toward the evolution of increasingly competent solutions by rewarding solution generality and uniqueness and problem tractability and difficulty. Relative (inverse-fitness) and absolute (static objective function) approaches to evaluating problem difficulty are explored and discussed. On a simple control task, this co-evolutionary algorithm was found to have significant advantages over a genetic algorithm with either a static fitness function or a fitness function that changes on a hand-tuned schedule.

Analyser-based phase contrast image reconstruction using geometrical optics.

PubMed

Kitchen, M J; Pavlov, K M; Siu, K K W; Menk, R H; Tromba, G; Lewis, R A

2007-07-21

Analyser-based phase contrast imaging can provide radiographs of exceptional contrast at high resolution (<100 microm), whilst quantitative phase and attenuation information can be extracted using just two images when the approximations of geometrical optics are satisfied. Analytical phase retrieval can be performed by fitting the analyser rocking curve with a symmetric Pearson type VII function. The Pearson VII function provided at least a 10% better fit to experimentally measured rocking curves than linear or Gaussian functions. A test phantom, a hollow nylon cylinder, was imaged at 20 keV using a Si(1 1 1) analyser at the ELETTRA synchrotron radiation facility. Our phase retrieval method yielded a more accurate object reconstruction than methods based on a linear fit to the rocking curve. Where reconstructions failed to map expected values, calculations of the Takagi number permitted distinction between the violation of the geometrical optics conditions and the failure of curve fitting procedures. The need for synchronized object/detector translation stages was removed by using a large, divergent beam and imaging the object in segments. Our image acquisition and reconstruction procedure enables quantitative phase retrieval for systems with a divergent source and accounts for imperfections in the analyser.

A method for cone fitting based on certain sampling strategy in CMM metrology

NASA Astrophysics Data System (ADS)

Zhang, Li; Guo, Chaopeng

2018-04-01

A method of cone fitting in engineering is explored and implemented to overcome shortcomings of current fitting method. In the current method, the calculations of the initial geometric parameters are imprecise which cause poor accuracy in surface fitting. A geometric distance function of cone is constructed firstly, then certain sampling strategy is defined to calculate the initial geometric parameters, afterwards nonlinear least-squares method is used to fit the surface. The experiment is designed to verify accuracy of the method. The experiment data prove that the proposed method can get initial geometric parameters simply and efficiently, also fit the surface precisely, and provide a new accurate way to cone fitting in the coordinate measurement.

Mitochondrial Recombination Reveals Mito-Mito Epistasis in Yeast.

PubMed

Wolters, John F; Charron, Guillaume; Gaspary, Alec; Landry, Christian R; Fiumera, Anthony C; Fiumera, Heather L

2018-05-01

Genetic variation in mitochondrial DNA (mtDNA) provides adaptive potential although the underlying genetic architecture of fitness components within mtDNAs is not known. To dissect functional variation within mtDNAs, we first identified naturally occurring mtDNAs that conferred high or low fitness in Saccharomyces cerevisiae by comparing growth in strains containing identical nuclear genotypes but different mtDNAs. During respiratory growth under temperature and oxidative stress conditions, mitotype effects were largely independent of nuclear genotypes even in the presence of mito-nuclear interactions. Recombinant mtDNAs were generated to determine fitness components within high- and low-fitness mtDNAs. Based on phenotypic distributions of isogenic strains containing recombinant mtDNAs, we found that multiple loci contributed to mitotype fitness differences. These mitochondrial loci interacted in epistatic, nonadditive ways in certain environmental conditions. Mito-mito epistasis ( i.e. , nonadditive interactions between mitochondrial loci) influenced fitness in progeny from four different crosses, suggesting that mito-mito epistasis is a widespread phenomenon in yeast and other systems with recombining mtDNAs. Furthermore, we found that interruption of coadapted mito-mito interactions produced recombinant mtDNAs with lower fitness. Our results demonstrate that mito-mito epistasis results in functional variation through mitochondrial recombination in fungi, providing modes for adaptive evolution and the generation of mito-mito incompatibilities. Copyright © 2018 by the Genetics Society of America.

On the Log-Normality of Historical Magnetic-Storm Intensity Statistics: Implications for Extreme-Event Probabilities

NASA Astrophysics Data System (ADS)

Love, J. J.; Rigler, E. J.; Pulkkinen, A. A.; Riley, P.

2015-12-01

An examination is made of the hypothesis that the statistics of magnetic-storm-maximum intensities are the realization of a log-normal stochastic process. Weighted least-squares and maximum-likelihood methods are used to fit log-normal functions to -Dst storm-time maxima for years 1957-2012; bootstrap analysis is used to established confidence limits on forecasts. Both methods provide fits that are reasonably consistent with the data; both methods also provide fits that are superior to those that can be made with a power-law function. In general, the maximum-likelihood method provides forecasts having tighter confidence intervals than those provided by weighted least-squares. From extrapolation of maximum-likelihood fits: a magnetic storm with intensity exceeding that of the 1859 Carrington event, -Dst > 850 nT, occurs about 1.13 times per century and a wide 95% confidence interval of [0.42, 2.41] times per century; a 100-yr magnetic storm is identified as having a -Dst > 880 nT (greater than Carrington) but a wide 95% confidence interval of [490, 1187] nT. This work is partially motivated by United States National Science and Technology Council and Committee on Space Research and International Living with a Star priorities and strategic plans for the assessment and mitigation of space-weather hazards.

Cardiorespiratory Fitness Is Associated With Cognitive Performance in Older But Not Younger Adults.

PubMed

Hayes, Scott M; Forman, Daniel E; Verfaellie, Mieke

2016-05-01

Aging is associated with declines in executive function and episodic memory. Cardiorespiratory fitness (CRF) has been associated with enhanced executive function in older adults (OA), but the relationship with episodic memory remains unclear. The purpose of the study was to examine the relationship between CRF and cognition in young and OA and whether CRF mitigates age-related cognitive decline. Participants completed exercise testing to evaluate CRF (peak VO2) and neuropsychological testing to assess cognition. In OA, peak VO2 was positively related to executive function, as well as to accuracy on an experimental face-name memory task and visual episodic memory. In young adults (YA), a relationship between peak VO2 and cognition was not evident. High-fit OA performed as well as YA on executive function measures. On episodic memory measures, YA performed better than high-fit OA, who in turn performed better than low-fit OA. CRF is positively associated with executive function and episodic memory in OA and attenuates age-related cognitive decline. We provide preliminary support for the age-dependence hypothesis, which posits that cognition and CRF relationships may be most readily observed during lifetime periods of significant neurocognitive development. Published by Oxford University Press on behalf of the Gerontological Society of America 2014.

flexsurv: A Platform for Parametric Survival Modeling in R

PubMed Central

Jackson, Christopher H.

2018-01-01

flexsurv is an R package for fully-parametric modeling of survival data. Any parametric time-to-event distribution may be fitted if the user supplies a probability density or hazard function, and ideally also their cumulative versions. Standard survival distributions are built in, including the three and four-parameter generalized gamma and F distributions. Any parameter of any distribution can be modeled as a linear or log-linear function of covariates. The package also includes the spline model of Royston and Parmar (2002), in which both baseline survival and covariate effects can be arbitrarily flexible parametric functions of time. The main model-fitting function, flexsurvreg, uses the familiar syntax of survreg from the standard survival package (Therneau 2016). Censoring or left-truncation are specified in ‘Surv’ objects. The models are fitted by maximizing the full log-likelihood, and estimates and confidence intervals for any function of the model parameters can be printed or plotted. flexsurv also provides functions for fitting and predicting from fully-parametric multi-state models, and connects with the mstate package (de Wreede, Fiocco, and Putter 2011). This article explains the methods and design principles of the package, giving several worked examples of its use. PMID:29593450

Plasma Physics Approximations in Ares

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

Managan, R. A.

Lee & More derived analytic forms for the transport properties of a plasma. Many hydro-codes use their formulae for electrical and thermal conductivity. The coefficients are complex functions of Fermi-Dirac integrals, F n( μ/θ ), the chemical potential, μ or ζ = ln(1+e μ/θ ), and the temperature, θ = kT. Since these formulae are expensive to compute, rational function approximations were fit to them. Approximations are also used to find the chemical potential, either μ or ζ . The fits use ζ as the independent variable instead of μ/θ . New fits are provided for A α (ζmore » ),A β (ζ ), ζ, f(ζ ) = (1 + e -μ/θ)F 1/2(μ/θ), F 1/2'/F 1/2, F c α, and F c β. In each case the relative error of the fit is minimized since the functions can vary by many orders of magnitude. The new fits are designed to exactly preserve the limiting values in the non-degenerate and highly degenerate limits or as ζ→ 0 or ∞. The original fits due to Lee & More and George Zimmerman are presented for comparison.« less

Adaptive Strategies and Person-Environment Fit among Functionally Limited Older Adults Aging in Place: A Mixed Methods Approach

PubMed Central

Lien, Laura L.; Steggell, Carmen D.; Iwarsson, Susanne

2015-01-01

Older adults prefer to age in place, necessitating a match between person and environment, or person-environment (P-E) fit. In occupational therapy practice, home modifications can support independence, but more knowledge is needed to optimize interventions targeting the housing situation of older adults. In response, this study aimed to explore the accessibility and usability of the home environment to further understand adaptive environmental behaviors. Mixed methods data were collected using objective and perceived indicators of P-E fit among 12 older adults living in community-dwelling housing. Quantitative data described objective P-E fit in terms of accessibility, while qualitative data explored perceived P-E fit in terms of usability. While accessibility problems were prevalent, participants’ perceptions of usability revealed a range of adaptive environmental behaviors employed to meet functional needs. A closer examination of the P-E interaction suggests that objective accessibility does not always stipulate perceived usability, which appears to be malleable with age, self-perception, and functional competency. Findings stress the importance of evaluating both objective and perceived indicators of P-E fit to provide housing interventions that support independence. Further exploration of adaptive processes in older age may serve to deepen our understanding of both P-E fit frameworks and theoretical models of aging well. PMID:26404352

Adaptive Strategies and Person-Environment Fit among Functionally Limited Older Adults Aging in Place: A Mixed Methods Approach.

PubMed

Lien, Laura L; Steggell, Carmen D; Iwarsson, Susanne

2015-09-23

Older adults prefer to age in place, necessitating a match between person and environment, or person-environment (P-E) fit. In occupational therapy practice, home modifications can support independence, but more knowledge is needed to optimize interventions targeting the housing situation of older adults. In response, this study aimed to explore the accessibility and usability of the home environment to further understand adaptive environmental behaviors. Mixed methods data were collected using objective and perceived indicators of P-E fit among 12 older adults living in community-dwelling housing. Quantitative data described objective P-E fit in terms of accessibility, while qualitative data explored perceived P-E fit in terms of usability. While accessibility problems were prevalent, participants' perceptions of usability revealed a range of adaptive environmental behaviors employed to meet functional needs. A closer examination of the P-E interaction suggests that objective accessibility does not always stipulate perceived usability, which appears to be malleable with age, self-perception, and functional competency. Findings stress the importance of evaluating both objective and perceived indicators of P-E fit to provide housing interventions that support independence. Further exploration of adaptive processes in older age may serve to deepen our understanding of both P-E fit frameworks and theoretical models of aging well.

Psychophysica: Mathematica notebooks for psychophysical experiments (cinematica--psychometrica--quest)

NASA Technical Reports Server (NTRS)

Watson, A. B.; Solomon, J. A.

1997-01-01

Psychophysica is a set of software tools for psychophysical research. Functions are provided for calibrated visual displays, for fitting and plotting of psychometric functions, and for the QUEST adaptive staircase procedure. The functions are written in the Mathematica programming language.

The joint fit of the BHMF and ERDF for the BAT AGN Sample

NASA Astrophysics Data System (ADS)

Weigel, Anna K.; Koss, Michael; Ricci, Claudio; Trakhtenbrot, Benny; Oh, Kyuseok; Schawinski, Kevin; Lamperti, Isabella

2018-01-01

A natural product of an AGN survey is the AGN luminosity function. This statistical measure describes the distribution of directly measurable AGN luminosities. Intrinsically, the shape of the luminosity function depends on the distribution of black hole masses and Eddington ratios. To constrain these fundamental AGN properties, the luminosity function thus has to be disentangled into the black hole mass and Eddington ratio distribution function. The BASS survey is unique as it allows such a joint fit for a large number of local AGN, is unbiased in terms of obscuration in the X-rays and provides black hole masses for type-1 and type-2 AGN. The black hole mass function at z ~ 0 represents an essential baseline for simulations and black hole growth models. The normalization of the Eddington ratio distribution function directly constrains the AGN fraction. Together, the BASS AGN luminosity, black hole mass and Eddington ratio distribution functions thus provide a complete picture of the local black hole population.

Curve Fitting via the Criterion of Least Squares. Applications of Algebra and Elementary Calculus to Curve Fitting. [and] Linear Programming in Two Dimensions: I. Applications of High School Algebra to Operations Research. Modules and Monographs in Undergraduate Mathematics and Its Applications Project. UMAP Units 321, 453.

ERIC Educational Resources Information Center

Alexander, John W., Jr.; Rosenberg, Nancy S.

This document consists of two modules. The first of these views applications of algebra and elementary calculus to curve fitting. The user is provided with information on how to: 1) construct scatter diagrams; 2) choose an appropriate function to fit specific data; 3) understand the underlying theory of least squares; 4) use a computer program to…

A mathematical description of the inclusive fitness theory.

PubMed

Wakano, Joe Yuichiro; Ohtsuki, Hisashi; Kobayashi, Yutaka

2013-03-01

Recent developments in the inclusive fitness theory have revealed that the direction of evolution can be analytically predicted in a wider class of models than previously thought, such as those models dealing with network structure. This paper aims to provide a mathematical description of the inclusive fitness theory. Specifically, we provide a general framework based on a Markov chain that can implement basic models of inclusive fitness. Our framework is based on the probability distribution of "offspring-to-parent map", from which the key concepts of the theory, such as fitness function, relatedness and inclusive fitness, are derived in a straightforward manner. We prove theorems showing that inclusive fitness always provides a correct prediction on which of two competing genes more frequently appears in the long run in the Markov chain. As an application of the theorems, we prove a general formula of the optimal dispersal rate in the Wright's island model with recurrent mutations. We also show the existence of the critical mutation rate, which does not depend on the number of islands and below which a positive dispersal rate evolves. Our framework can also be applied to lattice or network structured populations. Copyright © 2012 Elsevier Inc. All rights reserved.

Applying the transtheoretical model to promote functional fitness of community older adults participating in elastic band exercises.

PubMed

Yang, Hui-Ju; Chen, Kuei-Min; Chen, Ming-De; Wu, Hui-Chuan; Chang, Wen-Jane; Wang, Yueh-Chin; Huang, Hsin-Ting

2015-10-01

The transtheoretical model was applied to promote behavioural change and test the effects of a group senior elastic band exercise programme on the functional fitness of community older adults in the contemplation and preparation stages of behavioural change. Forming regular exercise habits is challenging for older adults. The transtheoretical model emphasizes using different strategies in various stages to facilitate behavioural changes. Quasi-experimental design with pre-test and post-tests on two groups. Six senior activity centres were randomly assigned to either the experimental or control group. The data were collected during 2011. A total of 199 participants were recruited and 169 participants completed the study (experimental group n = 84, control group n = 85). The elastic band exercises were performed for 40 minutes, three times per week for 6 months. The functional fitness of the participants was evaluated at baseline and at the third and sixth month of the intervention. Statistical analyses included a two-way mixed design analysis of variance, one-way repeated measures analysis of variance and an analysis of covariance. All of the functional fitness indicators had significant changes at post-tests from pre-test in the experimental group. The experimental group had better performances than the control group in all of the functional fitness indicators after three months and 6 months of the senior elastic band exercises. The exercise programme provided older adults with appropriate strategies for maintaining functional fitness, which improved significantly after the participants exercising regularly for 6 months. © 2015 John Wiley & Sons Ltd.

Dehydration protection provided by a maternal cuticle improves offspring fitness in the moss Funaria hygrometrica.

PubMed

Budke, Jessica M; Goffinet, Bernard; Jones, Cynthia S

2013-05-01

In bryophytes the sporophyte offspring are in contact with, nourished from, and partially surrounded by the maternal gametophyte throughout their lifespan. During early development, the moss sporophyte is covered by the calyptra, a cap of maternal gametophyte tissue that has a multilayered cuticle. In this study the effects on sporophyte offspring fitness of removing the maternal calyptra cuticle, in combination with dehydration stress, is experimentally determined. Using the moss Funaria hygrometrica, calyptra cuticle waxes were removed by chemical extraction and individuals were exposed to a short-term dehydration event. Sporophytes were returned to high humidity to complete development and then aspects of sporophyte survival, development, functional morphology, and reproductive output were measured. It was found that removal of calyptra cuticle under low humidity results in significant negative impacts to moss sporophyte fitness, resulting in decreased survival, increased tissue damage, incomplete sporophyte development, more peristome malformations, and decreased reproductive output. This study represents the strongest evidence to date that the structure of the calyptra cuticle functions in dehydration protection of the immature moss sporophyte. The investment in a maternal calyptra with a multilayered cuticle increases offspring fitness and provides a functional explanation for calyptra retention across mosses. The moss calyptra may represent the earliest occurance of maternal protection via structural provisioning of a cuticle in green plants.

Patient specific ankle-foot orthoses using rapid prototyping

PubMed Central

2011-01-01

Background Prefabricated orthotic devices are currently designed to fit a range of patients and therefore they do not provide individualized comfort and function. Custom-fit orthoses are superior to prefabricated orthotic devices from both of the above-mentioned standpoints. However, creating a custom-fit orthosis is a laborious and time-intensive manual process performed by skilled orthotists. Besides, adjustments made to both prefabricated and custom-fit orthoses are carried out in a qualitative manner. So both comfort and function can potentially suffer considerably. A computerized technique for fabricating patient-specific orthotic devices has the potential to provide excellent comfort and allow for changes in the standard design to meet the specific needs of each patient. Methods In this paper, 3D laser scanning is combined with rapid prototyping to create patient-specific orthoses. A novel process was engineered to utilize patient-specific surface data of the patient anatomy as a digital input, manipulate the surface data to an optimal form using Computer Aided Design (CAD) software, and then download the digital output from the CAD software to a rapid prototyping machine for fabrication. Results Two AFOs were rapidly prototyped to demonstrate the proposed process. Gait analysis data of a subject wearing the AFOs indicated that the rapid prototyped AFOs performed comparably to the prefabricated polypropylene design. Conclusions The rapidly prototyped orthoses fabricated in this study provided good fit of the subject's anatomy compared to a prefabricated AFO while delivering comparable function (i.e. mechanical effect on the biomechanics of gait). The rapid fabrication capability is of interest because it has potential for decreasing fabrication time and cost especially when a replacement of the orthosis is required. PMID:21226898

Progress Toward Optimizing Prosthetic Socket Fit and Suspension Using Elevated Vacuum to Promote Residual Limb Health.

PubMed

Wernke, Matthew M; Schroeder, Ryan M; Haynes, Michael L; Nolt, Lonnie L; Albury, Alexander W; Colvin, James M

2017-07-01

Objective: Prosthetic sockets are custom made for each amputee, yet there are no quantitative tools to determine the appropriateness of socket fit. Ensuring a proper socket fit can have significant effects on the health of residual limb soft tissues and overall function and acceptance of the prosthetic limb. Previous work found that elevated vacuum pressure data can detect movement between the residual limb and the prosthetic socket; however, the correlation between the two was specific to each user. The overall objective of this work is to determine the relationship between elevated vacuum pressure deviations and prosthetic socket fit. Approach: A tension compression machine was used to apply repeated controlled forces onto a residual limb model with sockets of different internal volume. Results: The vacuum pressure-displacement relationship was dependent on socket fit. The vacuum pressure data were sensitive enough to detect differences of 1.5% global volume and can likely detect differences even smaller. Limb motion was reduced as surface area of contact between the limb model and socket was maximized. Innovation: The results suggest that elevated vacuum pressure data provide information to quantify socket fit. Conclusions: This study provides evidence that the use of elevated vacuum pressure data may provide a method for prosthetists to quantify and monitor socket fit. Future studies should investigate the relationship between socket fit, limb motion, and limb health to define optimal socket fit parameters.

Predation-related costs and benefits of conspecific attraction in songbirds--an agent-based approach.

PubMed

Szymkowiak, Jakub; Kuczyński, Lechosław

2015-01-01

Songbirds that follow a conspecific attraction strategy in the habitat selection process prefer to settle in habitat patches already occupied by other individuals. This largely affects the patterns of their spatio-temporal distribution and leads to clustered breeding. Although making informed settlement decisions is expected to be beneficial for individuals, such territory clusters may potentially provide additional fitness benefits (e.g., through the dilution effect) or costs (e.g., possibly facilitating nest localization if predators respond functionally to prey distribution). Thus, we hypothesized that the fitness consequences of following a conspecific attraction strategy may largely depend on the composition of the predator community. We developed an agent-based model in which we simulated the settling behavior of birds that use a conspecific attraction strategy and breed in a multi-predator landscape with predators that exhibited different foraging strategies. Moreover, we investigated whether Bayesian updating of prior settlement decisions according to the perceived predation risk may improve the fitness of birds that rely on conspecific cues. Our results provide evidence that the fitness consequences of conspecific attraction are predation-related. We found that in landscapes dominated by predators able to respond functionally to prey distribution, clustered breeding led to fitness costs. However, this cost could be reduced if birds performed Bayesian updating of prior settlement decisions and perceived nesting with too many neighbors as a threat. Our results did not support the hypothesis that in landscapes dominated by incidental predators, clustered breeding as a byproduct of conspecific attraction provides fitness benefits through the dilution effect. We suggest that this may be due to the spatial scale of songbirds' aggregative behavior. In general, we provide evidence that when considering the fitness consequences of conspecific attraction for songbirds, one should expect a trade-off between the benefits of making informed decisions and the costs of clustering.

Predation-Related Costs and Benefits of Conspecific Attraction in Songbirds—An Agent-Based Approach

PubMed Central

Szymkowiak, Jakub; Kuczyński, Lechosław

2015-01-01

Songbirds that follow a conspecific attraction strategy in the habitat selection process prefer to settle in habitat patches already occupied by other individuals. This largely affects the patterns of their spatio-temporal distribution and leads to clustered breeding. Although making informed settlement decisions is expected to be beneficial for individuals, such territory clusters may potentially provide additional fitness benefits (e.g., through the dilution effect) or costs (e.g., possibly facilitating nest localization if predators respond functionally to prey distribution). Thus, we hypothesized that the fitness consequences of following a conspecific attraction strategy may largely depend on the composition of the predator community. We developed an agent-based model in which we simulated the settling behavior of birds that use a conspecific attraction strategy and breed in a multi-predator landscape with predators that exhibited different foraging strategies. Moreover, we investigated whether Bayesian updating of prior settlement decisions according to the perceived predation risk may improve the fitness of birds that rely on conspecific cues. Our results provide evidence that the fitness consequences of conspecific attraction are predation-related. We found that in landscapes dominated by predators able to respond functionally to prey distribution, clustered breeding led to fitness costs. However, this cost could be reduced if birds performed Bayesian updating of prior settlement decisions and perceived nesting with too many neighbors as a threat. Our results did not support the hypothesis that in landscapes dominated by incidental predators, clustered breeding as a byproduct of conspecific attraction provides fitness benefits through the dilution effect. We suggest that this may be due to the spatial scale of songbirds’ aggregative behavior. In general, we provide evidence that when considering the fitness consequences of conspecific attraction for songbirds, one should expect a trade-off between the benefits of making informed decisions and the costs of clustering. PMID:25790479

Vascular input function correction of inflow enhancement for improved pharmacokinetic modeling of liver DCE-MRI.

PubMed

Ning, Jia; Schubert, Tilman; Johnson, Kevin M; Roldán-Alzate, Alejandro; Chen, Huijun; Yuan, Chun; Reeder, Scott B

2018-06-01

To propose a simple method to correct vascular input function (VIF) due to inflow effects and to test whether the proposed method can provide more accurate VIFs for improved pharmacokinetic modeling. A spoiled gradient echo sequence-based inflow quantification and contrast agent concentration correction method was proposed. Simulations were conducted to illustrate improvement in the accuracy of VIF estimation and pharmacokinetic fitting. Animal studies with dynamic contrast-enhanced MR scans were conducted before, 1 week after, and 2 weeks after portal vein embolization (PVE) was performed in the left portal circulation of pigs. The proposed method was applied to correct the VIFs for model fitting. Pharmacokinetic parameters fitted using corrected and uncorrected VIFs were compared between different lobes and visits. Simulation results demonstrated that the proposed method can improve accuracy of VIF estimation and pharmacokinetic fitting. In animal study results, pharmacokinetic fitting using corrected VIFs demonstrated changes in perfusion consistent with changes expected after PVE, whereas the perfusion estimates derived by uncorrected VIFs showed no significant changes. The proposed correction method improves accuracy of VIFs and therefore provides more precise pharmacokinetic fitting. This method may be promising in improving the reliability of perfusion quantification. Magn Reson Med 79:3093-3102, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

A mathematical solution for the parameters of three interfering resonances

NASA Astrophysics Data System (ADS)

Han, X.; Shen, C. P.

2018-04-01

The multiple-solution problem in determining the parameters of three interfering resonances from a fit to an experimentally measured distribution is considered from a mathematical viewpoint. It is shown that there are four numerical solutions for a fit with three coherent Breit-Wigner functions. Although explicit analytical formulae cannot be derived in this case, we provide some constraint equations between the four solutions. For the cases of nonrelativistic and relativistic Breit-Wigner forms of amplitude functions, a numerical method is provided to derive the other solutions from that already obtained, based on the obtained constraint equations. In real experimental measurements with more complicated amplitude forms similar to Breit-Wigner functions, the same method can be deduced and performed to get numerical solutions. The good agreement between the solutions found using this mathematical method and those directly from the fit verifies the correctness of the constraint equations and mathematical methodology used. Supported by National Natural Science Foundation of China (NSFC) (11575017, 11761141009), the Ministry of Science and Technology of China (2015CB856701) and the CAS Center for Excellence in Particle Physics (CCEPP)

Pilot Randomized Trial of Integrated Cognitive-Behavioral Therapy and Neuromuscular Training for Juvenile Fibromyalgia: The FIT Teens Program.

PubMed

Kashikar-Zuck, Susmita; Black, William R; Pfeiffer, Megan; Peugh, James; Williams, Sara E; Ting, Tracy V; Thomas, Staci; Kitchen, Katie; Myer, Gregory D

2018-04-17

Cognitive-behavioral therapy (CBT) improves coping and daily functioning in adolescents with juvenile fibromyalgia (JFM), but is less effective in reducing pain. This pilot trial evaluated the efficacy of a novel intervention (Fibromyalgia Integrative Training for Teens; FIT Teens) which integrates CBT with specialized neuromuscular exercise training to enhance the effect of treatment on reducing pain and disability. Forty adolescents with JFM (12-18 years) were randomized to CBT-only or FIT Teens. Treatment was conducted in group-based sessions over 8 weeks with assessments at baseline, post-treatment, and 3-month follow-up (primary end point). Primary outcomes were pain intensity and functional disability. Secondary outcomes were depressive symptoms, fear of movement, and pain catastrophizing. Thirty-six participants (mean age=15.33 years; 90% female) completed the program. Intent to treat analysis was conducted to evaluate differences between the FIT Teens and CBT groups from baseline to 3-month follow-up, controlling for baseline group differences. Participants in the FIT Teens group showed significantly greater decreases in pain than the CBT group. FIT Teens participants also showed significant improvements in disability, but did not differ from CBT-only at the 3-month end point. Results provide preliminary evidence that the FIT Teens intervention provides added benefits beyond CBT in the treatment of JFM, particularly in pain reduction. Results from this pilot randomized controlled trial of a new combined CBT and specialized neuromuscular exercise intervention (FIT Teens), compared with CBT alone suggested that FIT Teens offers stronger treatment benefits than CBT alone at initial treatment follow-up, especially with respect to the outcome of pain reduction. Copyright © 2018 The American Pain Society. Published by Elsevier Inc. All rights reserved.

Functional Profiling Using the Saccharomyces Genome Deletion Project Collections.

PubMed

Nislow, Corey; Wong, Lai Hong; Lee, Amy Huei-Yi; Giaever, Guri

2016-09-01

The ability to measure and quantify the fitness of an entire organism requires considerably more complex approaches than simply using traditional "omic" methods that examine, for example, the abundance of RNA transcripts, proteins, or metabolites. The yeast deletion collections represent the only systematic, comprehensive set of null alleles for any organism in which such fitness measurements can be assayed. Generated by the Saccharomyces Genome Deletion Project, these collections allow the systematic and parallel analysis of gene functions using any measurable phenotype. The unique 20-bp molecular barcodes engineered into the genome of each deletion strain facilitate the massively parallel analysis of individual fitness. Here, we present functional genomic protocols for use with the yeast deletion collections. We describe how to maintain, propagate, and store the deletion collections and how to perform growth fitness assays on single and parallel screening platforms. Phenotypic fitness analyses of the yeast mutants, described in brief here, provide important insights into biological functions, mechanisms of drug action, and response to environmental stresses. It is important to bear in mind that the specific assays described in this protocol represent some of the many ways in which these collections can be assayed, and in this description particular attention is paid to maximizing throughput using growth as the phenotypic measure. © 2016 Cold Spring Harbor Laboratory Press.

SU-E-J-85: Leave-One-Out Perturbation (LOOP) Fitting Algorithm for Absolute Dose Film Calibration

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

Chu, A; Ahmad, M; Chen, Z

2014-06-01

Purpose: To introduce an outliers-recognition fitting routine for film dosimetry. It cannot only be flexible with any linear and non-linear regression but also can provide information for the minimal number of sampling points, critical sampling distributions and evaluating analytical functions for absolute film-dose calibration. Methods: The technique, leave-one-out (LOO) cross validation, is often used for statistical analyses on model performance. We used LOO analyses with perturbed bootstrap fitting called leave-one-out perturbation (LOOP) for film-dose calibration . Given a threshold, the LOO process detects unfit points (“outliers”) compared to other cohorts, and a bootstrap fitting process follows to seek any possibilitiesmore » of using perturbations for further improvement. After that outliers were reconfirmed by a traditional t-test statistics and eliminated, then another LOOP feedback resulted in the final. An over-sampled film-dose- calibration dataset was collected as a reference (dose range: 0-800cGy), and various simulated conditions for outliers and sampling distributions were derived from the reference. Comparisons over the various conditions were made, and the performance of fitting functions, polynomial and rational functions, were evaluated. Results: (1) LOOP can prove its sensitive outlier-recognition by its statistical correlation to an exceptional better goodness-of-fit as outliers being left-out. (2) With sufficient statistical information, the LOOP can correct outliers under some low-sampling conditions that other “robust fits”, e.g. Least Absolute Residuals, cannot. (3) Complete cross-validated analyses of LOOP indicate that the function of rational type demonstrates a much superior performance compared to the polynomial. Even with 5 data points including one outlier, using LOOP with rational function can restore more than a 95% value back to its reference values, while the polynomial fitting completely failed under the same conditions. Conclusion: LOOP can cooperate with any fitting routine functioning as a “robust fit”. In addition, it can be set as a benchmark for film-dose calibration fitting performance.« less

III. The importance of physical activity and aerobic fitness for cognitive control and memory in children.

PubMed

Chaddock-Heyman, Laura; Hillman, Charles H; Cohen, Neal J; Kramer, Arthur F

2014-12-01

In this chapter, we review literature that examines the association among physical activity, aerobic fitness, cognition, and the brain in elementary school children (ages 7-10 years). Specifically, physical activity and higher levels of aerobic fitness in children have been found to benefit brain structure, brain function, cognition, and school achievement. For example, higher fit children have larger brain volumes in the basal ganglia and hippocampus, which relate to superior performance on tasks of cognitive control and memory, respectively, when compared to their lower fit peers. Higher fit children also show superior brain function during tasks of cognitive control, better scores on tests of academic achievement, and higher performance on a real-world street crossing task, compared to lower fit and less active children. The cross-sectional findings are strengthened by a few randomized, controlled trials, which demonstrate that children randomly assigned to a physical activity intervention group show greater brain and cognitive benefits compared to a control group. Because these findings suggest that the developing brain is plastic and sensitive to lifestyle factors, we also discuss typical structural and functional brain maturation in children to provide context in which to interpret the effects of physical activity and aerobic fitness on the developing brain. This research is important because children are becoming increasingly sedentary, physically inactive, and unfit. An important goal of this review is to emphasize the importance of physical activity and aerobic fitness for the cognitive and brain health of today's youth. © 2014 The Society for Research in Child Development, Inc.

Using Person Response Functions to Investigate Areas of Person Misfit Related to Item Characteristics

ERIC Educational Resources Information Center

Walker, A. Adrienne; Jennings, Jeremy Kyle; Engelhard, George, Jr.

2018-01-01

Individual person fit analyses provide important information regarding the validity of test score inferences for an "individual" test taker. In this study, we use data from an undergraduate statistics test (N = 1135) to illustrate a two-step method that researchers and practitioners can use to examine individual person fit. First, person…

Scaling laws and universality for the strength of genetic interactions in yeast

NASA Astrophysics Data System (ADS)

Velenich, Andrea; Dai, Mingjie; Gore, Jeff

2012-02-01

Genetic interactions provide a window to the organization of the thousands of biochemical reactions in living cells. If two mutations affect unrelated cellular functions, the fitness effects of their combination can be easily predicted from the two separate fitness effects. However, because of interactions, for some pairs of mutations their combined fitness effect deviates from the naive prediction. We study genetic interactions in yeast cells by analyzing a publicly available database containing experimental growth rates of 5 million double mutants. We show that the characteristic strength of genetic interactions has a simple power law dependence on the fitness effects of the two interacting mutations and that the probability distribution of genetic interactions is a universal function. We further argue that the strength of genetic interactions depends only on the fitness effects of the interacting mutations and not on their biological origin in terms of single point mutations, entire gene knockouts or even more complicated physiological perturbations. Finally, we discuss the implications of the power law scaling of genetic interactions on the ruggedness of fitness landscapes and the consequent evolutionary dynamics.

Application of separable parameter space techniques to multi-tracer PET compartment modeling.

PubMed

Zhang, Jeff L; Michael Morey, A; Kadrmas, Dan J

2016-02-07

Multi-tracer positron emission tomography (PET) can image two or more tracers in a single scan, characterizing multiple aspects of biological functions to provide new insights into many diseases. The technique uses dynamic imaging, resulting in time-activity curves that contain contributions from each tracer present. The process of separating and recovering separate images and/or imaging measures for each tracer requires the application of kinetic constraints, which are most commonly applied by fitting parallel compartment models for all tracers. Such multi-tracer compartment modeling presents challenging nonlinear fits in multiple dimensions. This work extends separable parameter space kinetic modeling techniques, previously developed for fitting single-tracer compartment models, to fitting multi-tracer compartment models. The multi-tracer compartment model solution equations were reformulated to maximally separate the linear and nonlinear aspects of the fitting problem, and separable least-squares techniques were applied to effectively reduce the dimensionality of the nonlinear fit. The benefits of the approach are then explored through a number of illustrative examples, including characterization of separable parameter space multi-tracer objective functions and demonstration of exhaustive search fits which guarantee the true global minimum to within arbitrary search precision. Iterative gradient-descent algorithms using Levenberg-Marquardt were also tested, demonstrating improved fitting speed and robustness as compared to corresponding fits using conventional model formulations. The proposed technique overcomes many of the challenges in fitting simultaneous multi-tracer PET compartment models.

Application of separable parameter space techniques to multi-tracer PET compartment modeling

NASA Astrophysics Data System (ADS)

Zhang, Jeff L.; Morey, A. Michael; Kadrmas, Dan J.

2016-02-01

Multi-tracer positron emission tomography (PET) can image two or more tracers in a single scan, characterizing multiple aspects of biological functions to provide new insights into many diseases. The technique uses dynamic imaging, resulting in time-activity curves that contain contributions from each tracer present. The process of separating and recovering separate images and/or imaging measures for each tracer requires the application of kinetic constraints, which are most commonly applied by fitting parallel compartment models for all tracers. Such multi-tracer compartment modeling presents challenging nonlinear fits in multiple dimensions. This work extends separable parameter space kinetic modeling techniques, previously developed for fitting single-tracer compartment models, to fitting multi-tracer compartment models. The multi-tracer compartment model solution equations were reformulated to maximally separate the linear and nonlinear aspects of the fitting problem, and separable least-squares techniques were applied to effectively reduce the dimensionality of the nonlinear fit. The benefits of the approach are then explored through a number of illustrative examples, including characterization of separable parameter space multi-tracer objective functions and demonstration of exhaustive search fits which guarantee the true global minimum to within arbitrary search precision. Iterative gradient-descent algorithms using Levenberg-Marquardt were also tested, demonstrating improved fitting speed and robustness as compared to corresponding fits using conventional model formulations. The proposed technique overcomes many of the challenges in fitting simultaneous multi-tracer PET compartment models.

Optimality principles in the regulation of metabolic networks.

PubMed

Berkhout, Jan; Bruggeman, Frank J; Teusink, Bas

2012-08-29

One of the challenging tasks in systems biology is to understand how molecular networks give rise to emergent functionality and whether universal design principles apply to molecular networks. To achieve this, the biophysical, evolutionary and physiological constraints that act on those networks need to be identified in addition to the characterisation of the molecular components and interactions. Then, the cellular "task" of the network-its function-should be identified. A network contributes to organismal fitness through its function. The premise is that the same functions are often implemented in different organisms by the same type of network; hence, the concept of design principles. In biology, due to the strong forces of selective pressure and natural selection, network functions can often be understood as the outcome of fitness optimisation. The hypothesis of fitness optimisation to understand the design of a network has proven to be a powerful strategy. Here, we outline the use of several optimisation principles applied to biological networks, with an emphasis on metabolic regulatory networks. We discuss the different objective functions and constraints that are considered and the kind of understanding that they provide.

Physical activity interventions and children's mental function: An introduction and overview

PubMed Central

Tomporowski, Phillip D.; Lambourne, Kate; Okumura, Michelle S.

2011-01-01

Background This review provides a historical overview of physical activity interventions designed by American educators and an evaluation of research that has assessed the effects of exercise on children's mental function. Method Historical descriptions of the emergence of American physical education doctrine throughout the 20th century were evaluated. Prior reviews of studies that assessed the effects of single acute bouts of exercise and the effects of chronic exercise training on children's mental function were examined and the results of recent studies were summarized. Results Physical activity interventions designed for American children have reflected two competing views: activities should promote physical fitness and activities should promote social, emotional, and intellectual development. Research results indicate that exercise fosters the emergence of children's mental function; particularly executive functioning. The route by which physical activity impacts mental functioning is complex and is likely moderated by several variables, including physical fitness level, health status, and numerous psycho-social factors. Conclusion Physical activity interventions for children should be designed to meet multiple objectives; e.g., optimize physical fitness, promote health-related behaviors that offset obesity, and facilitate mental development. PMID:21420981

Using constraints and their value for optimization of large ODE systems

PubMed Central

Domijan, Mirela; Rand, David A.

2015-01-01

We provide analytical tools to facilitate a rigorous assessment of the quality and value of the fit of a complex model to data. We use this to provide approaches to model fitting, parameter estimation, the design of optimization functions and experimental optimization. This is in the context where multiple constraints are used to select or optimize a large model defined by differential equations. We illustrate the approach using models of circadian clocks and the NF-κB signalling system. PMID:25673300

Interpreting the Weibull fitting parameters for diffusion-controlled release data

NASA Astrophysics Data System (ADS)

Ignacio, Maxime; Chubynsky, Mykyta V.; Slater, Gary W.

2017-11-01

We examine the diffusion-controlled release of molecules from passive delivery systems using both analytical solutions of the diffusion equation and numerically exact Lattice Monte Carlo data. For very short times, the release process follows a √{ t } power law, typical of diffusion processes, while the long-time asymptotic behavior is exponential. The crossover time between these two regimes is determined by the boundary conditions and initial loading of the system. We show that while the widely used Weibull function provides a reasonable fit (in terms of statistical error), it has two major drawbacks: (i) it does not capture the correct limits and (ii) there is no direct connection between the fitting parameters and the properties of the system. Using a physically motivated interpolating fitting function that correctly includes both time regimes, we are able to predict the values of the Weibull parameters which allows us to propose a physical interpretation.

Is High Intensity Functional Training (HIFT)/CrossFit® Safe for Military Fitness Training?

PubMed Central

Poston, Walker S.C.; Haddock, Christopher K.; Heinrich, Katie M.; Jahnke, Sara A.; Jitnarin, Nattinee; Batchelor, David B.

2016-01-01

High-intensity functional training (HIFT) is a promising fitness paradigm that gained popularity among military populations. Rather than biasing workouts toward maximizing fitness domains such as aerobic endurance, HIFT workouts are designed to promote general physical preparedness. HIFT programs have proliferated due to concerns about the relevance of traditional physical training (PT), which historically focused on aerobic condition via running. Other concerns about traditional PT include: 1) the relevance of service fitness tests given current combat demands; 2) the perception that military PT is geared toward passing service fitness tests; and 3) that training for combat requires more than just aerobic endurance. Despite its’ popularity in the military, concerns have been raised about HIFT’s injury potential, leading to some approaches being labeled as “extreme conditioning programs” by several military and civilian experts. Given HIFT programs’ popularity in the military and concerns about injury, a review of data on HIFT injury potential is needed to inform military policy. The purpose of this review is to: 1) provide an overview of scientific methods used to appropriately compare injury rates among fitness activities; and 2) evaluate scientific data regarding HIFT injury risk compared to traditional military PT and other accepted fitness activities PMID:27391615

Is High-Intensity Functional Training (HIFT)/CrossFit Safe for Military Fitness Training?

PubMed

Poston, Walker S C; Haddock, Christopher K; Heinrich, Katie M; Jahnke, Sara A; Jitnarin, Nattinee; Batchelor, David B

2016-07-01

High-intensity functional training (HIFT) is a promising fitness paradigm that gained popularity among military populations. Rather than biasing workouts toward maximizing fitness domains such as aerobic endurance, HIFT workouts are designed to promote general physical preparedness. HIFT programs have proliferated as a result of concerns about the relevance of traditional physical training (PT), which historically focused on aerobic condition via running. Other concerns about traditional PT include: (1) the relevance of service fitness tests given current combat demands, (2) the perception that military PT is geared toward passing service fitness tests, and (3) that training for combat requires more than just aerobic endurance. Despite its' popularity in the military, concerns have been raised about HIFT's injury potential, leading to some approaches being labeled as "extreme conditioning programs" by several military and civilian experts. Given HIFT programs' popularity in the military and concerns about injury, a review of data on HIFT injury potential is needed to inform military policy. The purpose of this review is to: (1) provide an overview of scientific methods used to appropriately compare injury rates among fitness activities and (2) evaluate scientific data regarding HIFT injury risk compared to traditional military PT and other accepted fitness activities. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

Progress Toward Optimizing Prosthetic Socket Fit and Suspension Using Elevated Vacuum to Promote Residual Limb Health

PubMed Central

Wernke, Matthew M.; Schroeder, Ryan M.; Haynes, Michael L.; Nolt, Lonnie L.; Albury, Alexander W.; Colvin, James M.

2017-01-01

Objective: Prosthetic sockets are custom made for each amputee, yet there are no quantitative tools to determine the appropriateness of socket fit. Ensuring a proper socket fit can have significant effects on the health of residual limb soft tissues and overall function and acceptance of the prosthetic limb. Previous work found that elevated vacuum pressure data can detect movement between the residual limb and the prosthetic socket; however, the correlation between the two was specific to each user. The overall objective of this work is to determine the relationship between elevated vacuum pressure deviations and prosthetic socket fit. Approach: A tension compression machine was used to apply repeated controlled forces onto a residual limb model with sockets of different internal volume. Results: The vacuum pressure–displacement relationship was dependent on socket fit. The vacuum pressure data were sensitive enough to detect differences of 1.5% global volume and can likely detect differences even smaller. Limb motion was reduced as surface area of contact between the limb model and socket was maximized. Innovation: The results suggest that elevated vacuum pressure data provide information to quantify socket fit. Conclusions: This study provides evidence that the use of elevated vacuum pressure data may provide a method for prosthetists to quantify and monitor socket fit. Future studies should investigate the relationship between socket fit, limb motion, and limb health to define optimal socket fit parameters. PMID:28736683

EFFECTIVE HYPERFINE-STRUCTURE FUNCTIONS OF AMMONIA

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

Augustovičová, L.; Soldán, P.; Špirko, V., E-mail: spirko@marge.uochb.cas.cz

The hyperfine structure of the rotation-inversion ( v {sub 2} = 0{sup +}, 0{sup −}, 1{sup +}, 1{sup −}) states of the {sup 14}NH{sub 3} and {sup 15}NH{sub 3} ammonia isotopomers is rationalized in terms of effective (ro-inversional) hyperfine-structure (hfs) functions. These are determined by fitting to available experimental data using the Hougen’s effective hyperfine-structure Hamiltonian within the framework of the non-rigid inverter theory. Involving only a moderate number of mass independent fitting parameters, the fitted hfs functions provide a fairly close reproduction of a large majority of available experimental data, thus evidencing adequacy of these functions for reliable prediction.more » In future experiments, this may help us derive spectroscopic constants of observed inversion and rotation-inversion transitions deperturbed from hyperfine effects. The deperturbed band centers of ammonia come to the forefront of fundamental physics especially as the probes of a variable proton-to-electron mass ratio.« less

C-statistic fitting routines: User's manual and reference guide

NASA Technical Reports Server (NTRS)

Nousek, John A.; Farwana, Vida

1991-01-01

The computer program is discussed which can read several input files and provide a best set of values for the functions provided by the user, using either C-statistic or the chi(exp 2) statistic method. The program consists of one main routine and several functions and subroutines. Detail descriptions of each function and subroutine is presented. A brief description of the C-statistic and the reason for its application is also presented.

Comparison of yellow poplar growth models on the basis of derived growth analysis variables

Treesearch

Keith F. Jensen; Daniel A. Yaussy

1986-01-01

Quadratic and cubic polynomials, and Gompertz and Richards asymptotic models were fitted to yellow poplar growth data. These data included height, leaf area, leaf weight and new shoot height for 23 weeks. Seven growth analysis variables were estimated from each function. The Gompertz and Richards models fitted the data best and provided the most accurate derived...

Polynomial Fitting of DT-MRI Fiber Tracts Allows Accurate Estimation of Muscle Architectural Parameters

PubMed Central

Damon, Bruce M.; Heemskerk, Anneriet M.; Ding, Zhaohua

2012-01-01

Fiber curvature is a functionally significant muscle structural property, but its estimation from diffusion-tensor MRI fiber tracking data may be confounded by noise. The purpose of this study was to investigate the use of polynomial fitting of fiber tracts for improving the accuracy and precision of fiber curvature (κ) measurements. Simulated image datasets were created in order to provide data with known values for κ and pennation angle (θ). Simulations were designed to test the effects of increasing inherent fiber curvature (3.8, 7.9, 11.8, and 15.3 m−1), signal-to-noise ratio (50, 75, 100, and 150), and voxel geometry (13.8 and 27.0 mm3 voxel volume with isotropic resolution; 13.5 mm3 volume with an aspect ratio of 4.0) on κ and θ measurements. In the originally reconstructed tracts, θ was estimated accurately under most curvature and all imaging conditions studied; however, the estimates of κ were imprecise and inaccurate. Fitting the tracts to 2nd order polynomial functions provided accurate and precise estimates of κ for all conditions except very high curvature (κ=15.3 m−1), while preserving the accuracy of the θ estimates. Similarly, polynomial fitting of in vivo fiber tracking data reduced the κ values of fitted tracts from those of unfitted tracts and did not change the θ values. Polynomial fitting of fiber tracts allows accurate estimation of physiologically reasonable values of κ, while preserving the accuracy of θ estimation. PMID:22503094

Investigation of MHD flow structure and fluctuations by potassium lineshape fitting

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

Bauman, L.E.

1993-12-31

Multiple Potassium D-line emission absorption spectra from a high temperature, coal-fired flow have been fit to a radiative transfer, boundary layer flow model. The results of fitting spectra from the aerodynamic duct of the Department of Energy Coal-Fired Flow Facility provide information about the thickness and shape of the thermal boundary layer and the bulk potassium seed atom density in a simulated magnetohydrodynamic channel flow. Probability distribution functions for the entire set of more than six thousand spectra clearly indicate the typical values and magnitude of fluctuations for the flow: core temperature of 2538 {plus_minus} 20 K, near wall temperaturemore » of 1945 {plus_minus} 135 K, boundary layer width of about 1 cm, and potassium seed atom density of (5.1 {plus_minus} 0.8)x 10{sup 22}/m{sup 3}. Probability distribution functions for selected times during the eight hours of measurements indicate occasional periods of unstable combustion. In addition, broadband particle parameters during the unstable start of the test may be related to differing particle and gas temperatures. The results clearly demonstrate the ability of lineshape fitting to provide valuable data for diagnosing the high speed turbulent flow.« less

Cardiorespiratory Fitness and Cognitive Function in Midlife: Neuroprotection or Neuroselection?

PubMed Central

Belsky, Daniel W.; Caspi, Avshalom; Israel, Salomon; Blumenthal, James A.; Poulton, Richie; Moffitt, Terrie E.

2015-01-01

Objective To determine if better cognitive functioning at midlife among more physically fit individuals reflects “neuroprotection,” in which fitness protects against age-related cognitive decline, or “neuroselection,” in which children with higher cognitive functioning select into more active lifestyles. Methods Children in the Dunedin Longitudinal Study (N=1,037) completed the Wechsler Intelligence Scales and the Trail-Making, Rey-Delayed-Recall, and Grooved-Pegboard tasks as children and again at midlife (age-38). Adult cardiorespiratory fitness was assessed using a submaximal exercise test to estimate maximum-oxygen-consumption-adjusted-for-body-weight in milliliters/minute/kilogram (VO2max). We tested if more-fit individuals had better cognitive functioning than their less-fit counterparts (which could be consistent with neuroprotection), and if better childhood cognitive functioning predisposed to better adult cardiorespiratory fitness (neuroselection). Finally, we examined possible mechanisms of neuroselection. Results Participants with better cardiorespiratory fitness had higher cognitive test scores at midlife. However, fitness-associated advantages in cognitive functioning were present already in childhood. After accounting for childhood-baseline performance on the same cognitive tests, there was no association between cardiorespiratory fitness and midlife cognitive functioning. Socioeconomic and health advantages in childhood, and healthier lifestyles during young adulthood explained most of the association between childhood cognitive functioning and adult cardiorespiratory fitness. Interpretation We found no evidence for a neuroprotective effect of cardiorespiratory fitness as of midlife. Instead, children with better cognitive functioning are selecting into healthier lives. Fitness interventions may enhance cognitive functioning. But, observational and experimental studies testing neuroprotective effects of physical fitness should consider confounding by neuroselection. PMID:25601795

The Routine Fitting of Kinetic Data to Models

PubMed Central

Berman, Mones; Shahn, Ezra; Weiss, Marjory F.

1962-01-01

A mathematical formalism is presented for use with digital computers to permit the routine fitting of data to physical and mathematical models. Given a set of data, the mathematical equations describing a model, initial conditions for an experiment, and initial estimates for the values of model parameters, the computer program automatically proceeds to obtain a least squares fit of the data by an iterative adjustment of the values of the parameters. When the experimental measures are linear combinations of functions, the linear coefficients for a least squares fit may also be calculated. The values of both the parameters of the model and the coefficients for the sum of functions may be unknown independent variables, unknown dependent variables, or known constants. In the case of dependence, only linear dependencies are provided for in routine use. The computer program includes a number of subroutines, each one of which performs a special task. This permits flexibility in choosing various types of solutions and procedures. One subroutine, for example, handles linear differential equations, another, special non-linear functions, etc. The use of analytic or numerical solutions of equations is possible. PMID:13867975

Multigenerational effects of inbreeding in Cucurbita pepo ssp. texana (Cucurbitaceae).

PubMed

Hayes, C Nelson; Winsor, James A; Stephenson, Andrew G

2005-02-01

The shape of the fitness function relating the decline in fitness with coefficient of inbreeding (f) can provide evidence concerning the genetic basis of inbreeding depression, but few studies have examined inbreeding depression across a range of f using noncultivated species. Futhermore, studies have rarely examined the effects of inbreeding depression in the maternal parent on offspring fitness. To estimate the shape of the fitness function, we examined the relationship between f and fitness across a range off from 0.000 to 0.875 for components of both male and female fitness in Cucurbita pepo ssp. texana. Each measure of female fitness declined with f, including pistillate flower number, fruit number, seed number per fruit, seed mass per fruit, and percentage seed germination. Several aspects of male fitness also declined with f, including staminate flower number, pollen number per flower, and the number of days of flowering, although cumulative inbreeding depression was less severe for male (0.34) than for female function (0.39). Fitness tended to decline linearly with f between f = 0.00 and f = 0.75 for most traits and across cumulative lifetime fitness (mean = 0.66), suggesting that individual genes causing inbreeding depression are additive and the result of many alleles of small effect. However, most traits also showed a small reduction in inbreeding depression between f = 0.75 and f = 0.875, and evidence of purging or diminishing epistasis was found for in vitro pollen-tube growth rate. To examine inbreeding depression as a maternal effect, we performed outcross pollinations on f = 0.0 and f = 0.5 mothers and found that depression due to maternal inbreeding was 0.07, compared to 0.10 for offspring produced through one generation of selfing. In at least some families, maternal inbreeding reduced fruit number, seed number and mass, staminate flower number, pollen diameter, and pollen-tube growth rate. Collectively these results suggest that, while the fitness function appears to be largely linear for most traits, maternal effects may compound the effects of inbreeding depression in multigenerational studies, though this may be partially offset by purging or diminishing epistasis.

Fitting and Modeling in the ASC Data Analysis Environment

NASA Astrophysics Data System (ADS)

Doe, S.; Siemiginowska, A.; Joye, W.; McDowell, J.

As part of the AXAF Science Center (ASC) Data Analysis Environment, we will provide to the astronomical community a Fitting Application. We present a design of the application in this paper. Our design goal is to give the user the flexibility to use a variety of optimization techniques (Levenberg-Marquardt, maximum entropy, Monte Carlo, Powell, downhill simplex, CERN-Minuit, and simulated annealing) and fit statistics (chi (2) , Cash, variance, and maximum likelihood); our modular design allows the user easily to add their own optimization techniques and/or fit statistics. We also present a comparison of the optimization techniques to be provided by the Application. The high spatial and spectral resolutions that will be obtained with AXAF instruments require a sophisticated data modeling capability. We will provide not only a suite of astronomical spatial and spectral source models, but also the capability of combining these models into source models of up to four data dimensions (i.e., into source functions f(E,x,y,t)). We will also provide tools to create instrument response models appropriate for each observation.

Optimality Principles in the Regulation of Metabolic Networks

PubMed Central

Berkhout, Jan; Bruggeman, Frank J.; Teusink, Bas

2012-01-01

One of the challenging tasks in systems biology is to understand how molecular networks give rise to emergent functionality and whether universal design principles apply to molecular networks. To achieve this, the biophysical, evolutionary and physiological constraints that act on those networks need to be identified in addition to the characterisation of the molecular components and interactions. Then, the cellular “task” of the network—its function—should be identified. A network contributes to organismal fitness through its function. The premise is that the same functions are often implemented in different organisms by the same type of network; hence, the concept of design principles. In biology, due to the strong forces of selective pressure and natural selection, network functions can often be understood as the outcome of fitness optimisation. The hypothesis of fitness optimisation to understand the design of a network has proven to be a powerful strategy. Here, we outline the use of several optimisation principles applied to biological networks, with an emphasis on metabolic regulatory networks. We discuss the different objective functions and constraints that are considered and the kind of understanding that they provide. PMID:24957646

Application of separable parameter space techniques to multi-tracer PET compartment modeling

PubMed Central

Zhang, Jeff L; Morey, A Michael; Kadrmas, Dan J

2016-01-01

Multi-tracer positron emission tomography (PET) can image two or more tracers in a single scan, characterizing multiple aspects of biological functions to provide new insights into many diseases. The technique uses dynamic imaging, resulting in time-activity curves that contain contributions from each tracer present. The process of separating and recovering separate images and/or imaging measures for each tracer requires the application of kinetic constraints, which are most commonly applied by fitting parallel compartment models for all tracers. Such multi-tracer compartment modeling presents challenging nonlinear fits in multiple dimensions. This work extends separable parameter space kinetic modeling techniques, previously developed for fitting single-tracer compartment models, to fitting multi-tracer compartment models. The multi-tracer compartment model solution equations were reformulated to maximally separate the linear and nonlinear aspects of the fitting problem, and separable least-squares techniques were applied to effectively reduce the dimensionality of the nonlinear fit. The benefits of the approach are then explored through a number of illustrative examples, including characterization of separable parameter space multi-tracer objective functions and demonstration of exhaustive search fits which guarantee the true global minimum to within arbitrary search precision. Iterative gradient-descent algorithms using Levenberg–Marquardt were also tested, demonstrating improved fitting speed and robustness as compared to corresponding fits using conventional model formulations. The proposed technique overcomes many of the challenges in fitting simultaneous multi-tracer PET compartment models. PMID:26788888

Leak detection system and control using non-rigid bladder

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

Pillette, K.P.

1980-11-11

A portable system for early detection of leaks from suspect piping fittings, for example, as used on the ''christmas tree'' portion of a gas well provides an encapsulating bladder which sealably encapsulates the suspect fitting and collects leaks from the fitting. The apparatus provides, in the preferred embodiment, a bladder which can encase any suspect portion of the christmas tree (Or like piping system), such as for example, the choke jacket or other like fittings where maximum turbulence occurs as when gas or oil mixed with sand flows through the fitting. In the preferred embodiment, the collection of a leakmore » within the bladder causes a regulator to operate a control valve and halt the flow of gas, oil, or like flowing material through the piping system of which the suspect fitting is a part. The system can be applied to any other similar existing and operating piping arrangement where the detection of leaks from suspect fittings is desirable. The portable bladder and shut off arrangement of the present invention has particular application in the offshore oil and gas industry, where it can perform a safety function on unmanned gas/oil well platforms.« less

Progress in the preparation and application of modified biochar for improved contaminant removal from water and wastewater.

PubMed

Ahmed, Mohammad Boshir; Zhou, John L; Ngo, Huu H; Guo, Wenshan; Chen, Mengfang

2016-08-01

Modified biochar (BC) is reviewed in its preparation, functionality, applications and regeneration. The nature of precursor materials, preparatory conditions and modification methods are key factors influencing BC properties. Steam activation is unsuitable for improving BC surface functionality compared with chemical modifications. Alkali-treated BC possesses the highest surface functionality. Both alkali modified BC and nanomaterial impregnated BC composites are highly favorable for enhancing the adsorption of different contaminants from wastewater. Acidic treatment provides more oxygenated functional groups on BC surfaces. The Langmuir isotherm model provides the best fit for sorption equilibria of heavy metals and anionic contaminants, while the Freundlich isotherm model is the best fit for emerging contaminants. The pseudo 2(nd) order is the most appropriate model of sorption kinetics for all contaminants. Future research should focus on industry-scale applications and hybrid systems for contaminant removal due to scarcity of data. Copyright © 2016 Elsevier Ltd. All rights reserved.

Employing general fit-bases for construction of potential energy surfaces with an adaptive density-guided approach

NASA Astrophysics Data System (ADS)

Klinting, Emil Lund; Thomsen, Bo; Godtliebsen, Ian Heide; Christiansen, Ove

2018-02-01

We present an approach to treat sets of general fit-basis functions in a single uniform framework, where the functional form is supplied on input, i.e., the use of different functions does not require new code to be written. The fit-basis functions can be used to carry out linear fits to the grid of single points, which are generated with an adaptive density-guided approach (ADGA). A non-linear conjugate gradient method is used to optimize non-linear parameters if such are present in the fit-basis functions. This means that a set of fit-basis functions with the same inherent shape as the potential cuts can be requested and no other choices with regards to the fit-basis functions need to be taken. The general fit-basis framework is explored in relation to anharmonic potentials for model systems, diatomic molecules, water, and imidazole. The behaviour and performance of Morse and double-well fit-basis functions are compared to that of polynomial fit-basis functions for unsymmetrical single-minimum and symmetrical double-well potentials. Furthermore, calculations for water and imidazole were carried out using both normal coordinates and hybrid optimized and localized coordinates (HOLCs). Our results suggest that choosing a suitable set of fit-basis functions can improve the stability of the fitting routine and the overall efficiency of potential construction by lowering the number of single point calculations required for the ADGA. It is possible to reduce the number of terms in the potential by choosing the Morse and double-well fit-basis functions. These effects are substantial for normal coordinates but become even more pronounced if HOLCs are used.

Correlation of fitness landscapes from three orthologous TIM barrels originates from sequence and structure constraints

PubMed Central

Chan, Yvonne H.; Venev, Sergey V.; Zeldovich, Konstantin B.; Matthews, C. Robert

2017-01-01

Sequence divergence of orthologous proteins enables adaptation to environmental stresses and promotes evolution of novel functions. Limits on evolution imposed by constraints on sequence and structure were explored using a model TIM barrel protein, indole-3-glycerol phosphate synthase (IGPS). Fitness effects of point mutations in three phylogenetically divergent IGPS proteins during adaptation to temperature stress were probed by auxotrophic complementation of yeast with prokaryotic, thermophilic IGPS. Analysis of beneficial mutations pointed to an unexpected, long-range allosteric pathway towards the active site of the protein. Significant correlations between the fitness landscapes of distant orthologues implicate both sequence and structure as primary forces in defining the TIM barrel fitness landscape and suggest that fitness landscapes can be translocated in sequence space. Exploration of fitness landscapes in the context of a protein fold provides a strategy for elucidating the sequence-structure-fitness relationships in other common motifs. PMID:28262665

Qualitative analysis of feedback on functional imagery training: A novel motivational intervention for type 2 diabetes.

PubMed

Parham, Sophie C; Kavanagh, David J; Shimada, Mika; May, Jon; Andrade, Jackie

2018-03-01

Effective motivational support is needed in chronic disease management. This study was undertaken to improve a novel type 2 diabetes motivational intervention, (functional imagery training, FIT) based on participant feedback and results from a self-management randomised controlled trial. Qualitative inductive thematic analysis of semi-structured interviews. Open-ended questions on participant experiences of the FIT intervention content, process, most/least helpful features, suggestions for improvement and general feedback. Eight themes emerged. Participants thought FIT promoted autonomy and self-awareness. They found the intervention interesting and helpful in keeping their health on track through accountability provided by regular phone calls. However, boredom with repetitive use of imagery, feeling inadequately equipped to manage unhealthy cravings, and difficulty with the time commitment was reported by some. Supplementary written material was recommended. Several well-received features of FIT overlapped with those from traditional motivational interviewing. FIT sessions should ensure content is regularly adapted to new health-enhancing goals. After self-management behaviour becomes habitual, imagery practice could be restricted to challenging contexts. Provision of a written rationale and use of mindfulness for cravings is recommended. With these improvements, the impact of FIT on diabetic control may be substantially enhanced.

Interactive Spectral Analysis and Computation (ISAAC)

NASA Technical Reports Server (NTRS)

Lytle, D. M.

1992-01-01

Isaac is a task in the NSO external package for IRAF. A descendant of a FORTRAN program written to analyze data from a Fourier transform spectrometer, the current implementation has been generalized sufficiently to make it useful for general spectral analysis and other one dimensional data analysis tasks. The user interface for Isaac is implemented as an interpreted mini-language containing a powerful, programmable vector calculator. Built-in commands provide much of the functionality needed to produce accurate line lists from input spectra. These built-in functions include automated spectral line finding, least squares fitting of Voigt profiles to spectral lines including equality constraints, various filters including an optimal filter construction tool, continuum fitting, and various I/O functions.

Molecular radiotherapy: the NUKFIT software for calculating the time-integrated activity coefficient.

PubMed

Kletting, P; Schimmel, S; Kestler, H A; Hänscheid, H; Luster, M; Fernández, M; Bröer, J H; Nosske, D; Lassmann, M; Glatting, G

2013-10-01

Calculation of the time-integrated activity coefficient (residence time) is a crucial step in dosimetry for molecular radiotherapy. However, available software is deficient in that it is either not tailored for the use in molecular radiotherapy and/or does not include all required estimation methods. The aim of this work was therefore the development and programming of an algorithm which allows for an objective and reproducible determination of the time-integrated activity coefficient and its standard error. The algorithm includes the selection of a set of fitting functions from predefined sums of exponentials and the choice of an error model for the used data. To estimate the values of the adjustable parameters an objective function, depending on the data, the parameters of the error model, the fitting function and (if required and available) Bayesian information, is minimized. To increase reproducibility and user-friendliness the starting values are automatically determined using a combination of curve stripping and random search. Visual inspection, the coefficient of determination, the standard error of the fitted parameters, and the correlation matrix are provided to evaluate the quality of the fit. The functions which are most supported by the data are determined using the corrected Akaike information criterion. The time-integrated activity coefficient is estimated by analytically integrating the fitted functions. Its standard error is determined assuming Gaussian error propagation. The software was implemented using MATLAB. To validate the proper implementation of the objective function and the fit functions, the results of NUKFIT and SAAM numerical, a commercially available software tool, were compared. The automatic search for starting values was successfully tested for reproducibility. The quality criteria applied in conjunction with the Akaike information criterion allowed the selection of suitable functions. Function fit parameters and their standard error estimated by using SAAM numerical and NUKFIT showed differences of <1%. The differences for the time-integrated activity coefficients were also <1% (standard error between 0.4% and 3%). In general, the application of the software is user-friendly and the results are mathematically correct and reproducible. An application of NUKFIT is presented for three different clinical examples. The software tool with its underlying methodology can be employed to objectively and reproducibly estimate the time integrated activity coefficient and its standard error for most time activity data in molecular radiotherapy.

Efficient scatter distribution estimation and correction in CBCT using concurrent Monte Carlo fitting

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

Bootsma, G. J., E-mail: Gregory.Bootsma@rmp.uhn.on.ca; Verhaegen, F.; Medical Physics Unit, Department of Oncology, McGill University, Montreal, Quebec H3G 1A4

2015-01-15

Purpose: X-ray scatter is a significant impediment to image quality improvements in cone-beam CT (CBCT). The authors present and demonstrate a novel scatter correction algorithm using a scatter estimation method that simultaneously combines multiple Monte Carlo (MC) CBCT simulations through the use of a concurrently evaluated fitting function, referred to as concurrent MC fitting (CMCF). Methods: The CMCF method uses concurrently run MC CBCT scatter projection simulations that are a subset of the projection angles used in the projection set, P, to be corrected. The scattered photons reaching the detector in each MC simulation are simultaneously aggregated by an algorithmmore » which computes the scatter detector response, S{sub MC}. S{sub MC} is fit to a function, S{sub F}, and if the fit of S{sub F} is within a specified goodness of fit (GOF), the simulations are terminated. The fit, S{sub F}, is then used to interpolate the scatter distribution over all pixel locations for every projection angle in the set P. The CMCF algorithm was tested using a frequency limited sum of sines and cosines as the fitting function on both simulated and measured data. The simulated data consisted of an anthropomorphic head and a pelvis phantom created from CT data, simulated with and without the use of a compensator. The measured data were a pelvis scan of a phantom and patient taken on an Elekta Synergy platform. The simulated data were used to evaluate various GOF metrics as well as determine a suitable fitness value. The simulated data were also used to quantitatively evaluate the image quality improvements provided by the CMCF method. A qualitative analysis was performed on the measured data by comparing the CMCF scatter corrected reconstruction to the original uncorrected and corrected by a constant scatter correction reconstruction, as well as a reconstruction created using a set of projections taken with a small cone angle. Results: Pearson’s correlation, r, proved to be a suitable GOF metric with strong correlation with the actual error of the scatter fit, S{sub F}. Fitting the scatter distribution to a limited sum of sine and cosine functions using a low-pass filtered fast Fourier transform provided a computationally efficient and accurate fit. The CMCF algorithm reduces the number of photon histories required by over four orders of magnitude. The simulated experiments showed that using a compensator reduced the computational time by a factor between 1.5 and 1.75. The scatter estimates for the simulated and measured data were computed between 35–93 s and 114–122 s, respectively, using 16 Intel Xeon cores (3.0 GHz). The CMCF scatter correction improved the contrast-to-noise ratio by 10%–50% and reduced the reconstruction error to under 3% for the simulated phantoms. Conclusions: The novel CMCF algorithm significantly reduces the computation time required to estimate the scatter distribution by reducing the statistical noise in the MC scatter estimate and limiting the number of projection angles that must be simulated. Using the scatter estimate provided by the CMCF algorithm to correct both simulated and real projection data showed improved reconstruction image quality.« less

Optimizing Exercise Programs for Arthritis Patients.

ERIC Educational Resources Information Center

Boulware, Dennis W.; Byrd, Shannon L.

1993-01-01

Exercise can help decrease pain and improve function in people with rheumatoid arthritis or osteoarthritis. Physicians must provide individualized, realistic, enjoyable exercise programs that help affected joints, build fitness, and maximize patient compliance. Physicians must also provide appropriate follow-up care, adjusting the exercise program…

Probability Density Functions of Observed Rainfall in Montana

NASA Technical Reports Server (NTRS)

Larsen, Scott D.; Johnson, L. Ronald; Smith, Paul L.

1995-01-01

The question of whether a rain rate probability density function (PDF) can vary uniformly between precipitation events is examined. Image analysis on large samples of radar echoes is possible because of advances in technology. The data provided by such an analysis easily allow development of radar reflectivity factors (and by extension rain rate) distribution. Finding a PDF becomes a matter of finding a function that describes the curve approximating the resulting distributions. Ideally, one PDF would exist for all cases; or many PDF's that have the same functional form with only systematic variations in parameters (such as size or shape) exist. Satisfying either of theses cases will, validate the theoretical basis of the Area Time Integral (ATI). Using the method of moments and Elderton's curve selection criteria, the Pearson Type 1 equation was identified as a potential fit for 89 percent of the observed distributions. Further analysis indicates that the Type 1 curve does approximate the shape of the distributions but quantitatively does not produce a great fit. Using the method of moments and Elderton's curve selection criteria, the Pearson Type 1 equation was identified as a potential fit for 89% of the observed distributions. Further analysis indicates that the Type 1 curve does approximate the shape of the distributions but quantitatively does not produce a great fit.

Transient myocardial tissue and function changes during a marathon in less fit marathon runners.

PubMed

Gaudreault, Valerie; Tizon-Marcos, Helena; Poirier, Paul; Pibarot, Philippe; Gilbert, Philippe; Amyot, Marc; Rodés-Cabau, Josep; Després, Jean-Pierre; Bertrand, Olivier; Larose, Eric

2013-10-01

Although regular physical activity improves health, strenuous exercise might transiently increase cardiac risk. Training and fitness might provide protection. We prospectively studied 20 recreational marathon runners without known cardiovascular disease or symptoms: at peak training before, immediately after, and 3 months after a 42.2-km marathon. Changes in global/segmental myocardial function, edema, resting perfusion, and fibrosis were measured. At peak training, runners exercised 8.1 ± 2.3 hours and 62 ± 18 km per week with mean maximal oxygen consumption (VO2max) of 53.2 ± 8.3 mL/kg/min. In response to the marathon, global left ventricular and right ventricular ejection fraction decreased in half of the runners; these runners had poorer peak training distance, training time, and fitness level. Change in global left ventricular ejection fraction was associated with VO2max. Overall, 36% of segments developed edema, 53% decreased function, and 59% decreased perfusion. Significant agreement was observed between segment decreasing function, decreasing perfusion, and developing edema. Myocardial changes were reversible at 3 months. Completing a marathon leads to localized myocardial edema, diminished perfusion, and decreased function occurring more extensively in less trained and fit runners. Although reversible, these changes might contribute to the transient increase in cardiac risk reported during sustained vigorous exercise. Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Confirmatory factor analysis reveals a latent cognitive structure common to bipolar disorder, schizophrenia, and normal controls.

PubMed

Schretlen, David J; Peña, Javier; Aretouli, Eleni; Orue, Izaskun; Cascella, Nicola G; Pearlson, Godfrey D; Ojeda, Natalia

2013-06-01

We sought to determine whether a single hypothesized latent factor structure would characterize cognitive functioning in three distinct groups. We assessed 576 adults (340 community controls, 126 adults with bipolar disorder, and 110 adults with schizophrenia) using 15 measures derived from nine cognitive tests. Confirmatory factor analysis (CFA) was conducted to examine the fit of a hypothesized six-factor model. The hypothesized factors included attention, psychomotor speed, verbal memory, visual memory, ideational fluency, and executive functioning. The six-factor model provided an excellent fit for all three groups [for community controls, root mean square error of approximation (RMSEA) <0.048 and comparative fit index (CFI) = 0.99; for adults with bipolar disorder, RMSEA = 0.071 and CFI = 0.99; and for adults with schizophrenia, RMSEA = 0.06 and CFI = 0.98]. Alternate models that combined fluency with processing speed or verbal and visual memory reduced the goodness of fit. Multi-group CFA results supported factor invariance across the three groups. Confirmatory factor analysis supported a single six-factor structure of cognitive functioning among patients with schizophrenia or bipolar disorder and community controls. While the three groups clearly differ in level of performance, they share a common underlying architecture of information processing abilities. These cognitive factors could provide useful targets for clinical trials of treatments that aim to enhance information processing in persons with neurological and neuropsychiatric disorders. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Development and validation of criterion-referenced clinically relevant fitness standards for maintaining physical independence in later years.

PubMed

Rikli, Roberta E; Jones, C Jessie

2013-04-01

To develop and validate criterion-referenced fitness standards for older adults that predict the level of capacity needed for maintaining physical independence into later life. The proposed standards were developed for use with a previously validated test battery for older adults-the Senior Fitness Test (Rikli, R. E., & Jones, C. J. (2001). Development and validation of a functional fitness test for community--residing older adults. Journal of Aging and Physical Activity, 6, 127-159; Rikli, R. E., & Jones, C. J. (1999a). Senior fitness test manual. Champaign, IL: Human Kinetics.). A criterion measure to assess physical independence was identified. Next, scores from a subset of 2,140 "moderate-functioning" older adults from a larger cross-sectional database, together with findings from longitudinal research on physical capacity and aging, were used as the basis for proposing fitness standards (performance cut points) associated with having the ability to function independently. Validity and reliability analyses were conducted to test the standards for their accuracy and consistency as predictors of physical independence. Performance standards are presented for men and women ages 60-94 indicating the level of fitness associated with remaining physically independent until late in life. Reliability and validity indicators for the standards ranged between .79 and .97. The proposed standards provide easy-to-use, previously unavailable methods for evaluating physical capacity in older adults relative to that associated with physical independence. Most importantly, the standards can be used in planning interventions that target specific areas of weakness, thus reducing risk for premature loss of mobility and independence.

Modified hyperbolic sine model for titanium dioxide-based memristive thin films

NASA Astrophysics Data System (ADS)

Abu Bakar, Raudah; Syahirah Kamarozaman, Nur; Fazlida Hanim Abdullah, Wan; Herman, Sukreen Hana

2018-03-01

Since the emergence of memristor as the newest fundamental circuit elements, studies on memristor modeling have been evolved. To date, the developed models were based on the linear model, linear ionic drift model using different window functions, tunnelling barrier model and hyperbolic-sine function based model. Although using hyperbolic-sine function model could predict the memristor electrical properties, the model was not well fitted to the experimental data. In order to improve the performance of the hyperbolic-sine function model, the state variable equation was modified. On the one hand, the addition of window function cannot provide an improved fitting. By multiplying the Yakopcic’s state variable model to Chang’s model on the other hand resulted in the closer agreement with the TiO2 thin film experimental data. The percentage error was approximately 2.15%.

Approaches to organizing public relations functions in healthcare.

PubMed

Guy, Bonnie; Williams, David R; Aldridge, Alicia; Roggenkamp, Susan D

2007-01-01

This article provides health care audiences with a framework for understanding different perspectives of the role and functions of public relations in healthcare organizations and the resultant alternatives for organizing and enacting public relations functions. Using an example of a current issue receiving much attention in US healthcare (improving rates of organ donation), the article provides examples of how these different perspectives influence public relations goals and objectives, definitions of 'public', activities undertaken, who undertakes them and where they fit into the organizational hierarchy.

Parameterizing sorption isotherms using a hybrid global-local fitting procedure.

PubMed

Matott, L Shawn; Singh, Anshuman; Rabideau, Alan J

2017-05-01

Predictive modeling of the transport and remediation of groundwater contaminants requires an accurate description of the sorption process, which is usually provided by fitting an isotherm model to site-specific laboratory data. Commonly used calibration procedures, listed in order of increasing sophistication, include: trial-and-error, linearization, non-linear regression, global search, and hybrid global-local search. Given the considerable variability in fitting procedures applied in published isotherm studies, we investigated the importance of algorithm selection through a series of numerical experiments involving 13 previously published sorption datasets. These datasets, considered representative of state-of-the-art for isotherm experiments, had been previously analyzed using trial-and-error, linearization, or non-linear regression methods. The isotherm expressions were re-fit using a 3-stage hybrid global-local search procedure (i.e. global search using particle swarm optimization followed by Powell's derivative free local search method and Gauss-Marquardt-Levenberg non-linear regression). The re-fitted expressions were then compared to previously published fits in terms of the optimized weighted sum of squared residuals (WSSR) fitness function, the final estimated parameters, and the influence on contaminant transport predictions - where easily computed concentration-dependent contaminant retardation factors served as a surrogate measure of likely transport behavior. Results suggest that many of the previously published calibrated isotherm parameter sets were local minima. In some cases, the updated hybrid global-local search yielded order-of-magnitude reductions in the fitness function. In particular, of the candidate isotherms, the Polanyi-type models were most likely to benefit from the use of the hybrid fitting procedure. In some cases, improvements in fitness function were associated with slight (<10%) changes in parameter values, but in other cases significant (>50%) changes in parameter values were noted. Despite these differences, the influence of isotherm misspecification on contaminant transport predictions was quite variable and difficult to predict from inspection of the isotherms. Copyright © 2017 Elsevier B.V. All rights reserved.

dPotFit: A computer program to fit diatomic molecule spectral data to potential energy functions

NASA Astrophysics Data System (ADS)

Le Roy, Robert J.

2017-01-01

This paper describes program dPotFit, which performs least-squares fits of diatomic molecule spectroscopic data consisting of any combination of microwave, infrared or electronic vibrational bands, fluorescence series, and tunneling predissociation level widths, involving one or more electronic states and one or more isotopologs, and for appropriate systems, second virial coefficient data, to determine analytic potential energy functions defining the observed levels and other properties of each state. Four families of analytical potential functions are available for fitting in the current version of dPotFit: the Expanded Morse Oscillator (EMO) function, the Morse/Long-Range (MLR) function, the Double-Exponential/Long-Range (DELR) function, and the 'Generalized Potential Energy Function' (GPEF) of Šurkus, which incorporates a variety of polynomial functional forms. In addition, dPotFit allows sets of experimental data to be tested against predictions generated from three other families of analytic functions, namely, the 'Hannover Polynomial' (or "X-expansion") function, and the 'Tang-Toennies' and Scoles-Aziz 'HFD', exponential-plus-van der Waals functions, and from interpolation-smoothed pointwise potential energies, such as those obtained from ab initio or RKR calculations. dPotFit also allows the fits to determine atomic-mass-dependent Born-Oppenheimer breakdown functions, and singlet-state Λ-doubling, or 2Σ splitting radial strength functions for one or more electronic states. dPotFit always reports both the 95% confidence limit uncertainty and the "sensitivity" of each fitted parameter; the latter indicates the number of significant digits that must be retained when rounding fitted parameters, in order to ensure that predictions remain in full agreement with experiment. It will also, if requested, apply a "sequential rounding and refitting" procedure to yield a final parameter set defined by a minimum number of significant digits, while ensuring no significant loss of accuracy in the predictions yielded by those parameters.

14 CFR 121.921 - Training devices and simulators.

Code of Federal Regulations, 2010 CFR

2010-01-01

... REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Advanced Qualification Program § 121.921 Training... provide for its serviceability and fitness to perform its intended function as approved by the FAA. ...

Alzheimer disease alters the relationship of cardiorespiratory fitness with brain activity during the stroop task.

PubMed

Vidoni, Eric D; Gayed, Matthew R; Honea, Robyn A; Savage, Cary R; Hobbs, Derek; Burns, Jeffrey M

2013-07-01

Despite mounting evidence that physical activity has positive benefits for brain and cognitive health, there has been little characterization of the relationship between cardiorespiratory (CR) fitness and cognition-associated brain activity as measured by functional magnetic resonance imaging (fMRI). The lack of evidence is particularly glaring for diseases such as Alzheimer disease (AD) that degrade cognitive and functional performance. The aim of this study was to describe the relationship between regional brain activity during cognitive tasks and CR fitness level in people with and without AD. A case-control, single-observation study design was used. Thirty-four individuals (18 without dementia and 16 in the earliest stages of AD) completed maximal exercise testing and performed a Stroop task during fMRI. Cardiorespiratory fitness was inversely associated with anterior cingulate activity in the participants without dementia (r=-.48, P=.05) and unassociated with activation in those with AD (P>.7). Weak associations of CR fitness and middle frontal cortex were noted. The wide age range and the use of a single task in fMRI rather than multiple tasks challenging different cognitive capacities were limitations of the study. The results offer further support of the relationship between CR fitness and regional brain activity. However, this relationship may be attenuated by disease. Future work in this area may provide clinicians and researchers with interpretable and dependable regional fMRI biomarker signatures responsive to exercise intervention. It also may shed light on mechanisms by which exercise can support cognitive function.

BMDS: A Collection of R Functions for Bayesian Multidimensional Scaling

ERIC Educational Resources Information Center

Okada, Kensuke; Shigemasu, Kazuo

2009-01-01

Bayesian multidimensional scaling (MDS) has attracted a great deal of attention because: (1) it provides a better fit than do classical MDS and ALSCAL; (2) it provides estimation errors of the distances; and (3) the Bayesian dimension selection criterion, MDSIC, provides a direct indication of optimal dimensionality. However, Bayesian MDS is not…

Feature Detection and Curve Fitting Using Fast Walsh Transforms for Shock Tracking: Applications

NASA Technical Reports Server (NTRS)

Gnoffo, Peter A.

2017-01-01

Walsh functions form an orthonormal basis set consisting of square waves. Square waves make the system well suited for detecting and representing functions with discontinuities. Given a uniform distribution of 2p cells on a one-dimensional element, it has been proven that the inner product of the Walsh Root function for group p with every polynomial of degree < or = (p - 1) across the element is identically zero. It has also been proven that the magnitude and location of a discontinuous jump, as represented by a Heaviside function, are explicitly identified by its Fast Walsh Transform (FWT) coefficients. These two proofs enable an algorithm that quickly provides a Weighted Least Squares fit to distributions across the element that include a discontinuity. The detection of a discontinuity enables analytic relations to locally describe its evolution and provide increased accuracy. Time accurate examples are provided for advection, Burgers equation, and Riemann problems (diaphragm burst) in closed tubes and de Laval nozzles. New algorithms to detect up to two C0 and/or C1 discontinuities within a single element are developed for application to the Riemann problem, in which a contact discontinuity and shock wave form after the diaphragm bursts.

Constraining the optical depth of galaxies and velocity bias with cross-correlation between the kinetic Sunyaev-Zeldovich effect and the peculiar velocity field

NASA Astrophysics Data System (ADS)

Ma, Yin-Zhe; Gong, Guo-Dong; Sui, Ning; He, Ping

2018-03-01

We calculate the cross-correlation function < (Δ T/T)({v}\\cdot \\hat{n}/σ _v) > between the kinetic Sunyaev-Zeldovich (kSZ) effect and the reconstructed peculiar velocity field using linear perturbation theory, with the aim of constraining the optical depth τ and peculiar velocity bias of central galaxies with Planck data. We vary the optical depth τ and the velocity bias function bv(k) = 1 + b(k/k0)n, and fit the model to the data, with and without varying the calibration parameter y0 that controls the vertical shift of the correlation function. By constructing a likelihood function and constraining the τ, b and n parameters, we find that the quadratic power-law model of velocity bias, bv(k) = 1 + b(k/k0)2, provides the best fit to the data. The best-fit values are τ = (1.18 ± 0.24) × 10-4, b=-0.84^{+0.16}_{-0.20} and y0=(12.39^{+3.65}_{-3.66})× 10^{-9} (68 per cent confidence level). The probability of b > 0 is only 3.12 × 10-8 for the parameter b, which clearly suggests a detection of scale-dependent velocity bias. The fitting results indicate that the large-scale (k ≤ 0.1 h Mpc-1) velocity bias is unity, while on small scales the bias tends to become negative. The value of τ is consistent with the stellar mass-halo mass and optical depth relationship proposed in the literature, and the negative velocity bias on small scales is consistent with the peak background split theory. Our method provides a direct tool for studying the gaseous and kinematic properties of galaxies.

A multiplicative process for generating a beta-like survival function with application to the UK 2016 EU referendum results

NASA Astrophysics Data System (ADS)

Fenner, Trevor; Kaufmann, Eric; Levene, Mark; Loizou, George

Human dynamics and sociophysics suggest statistical models that may explain and provide us with better insight into social phenomena. Contextual and selection effects tend to produce extreme values in the tails of rank-ordered distributions of both census data and district-level election outcomes. Models that account for this nonlinearity generally outperform linear models. Fitting nonlinear functions based on rank-ordering census and election data therefore improves the fit of aggregate voting models. This may help improve ecological inference, as well as election forecasting in majoritarian systems. We propose a generative multiplicative decrease model that gives rise to a rank-order distribution and facilitates the analysis of the recent UK EU referendum results. We supply empirical evidence that the beta-like survival function, which can be generated directly from our model, is a close fit to the referendum results, and also may have predictive value when covariate data are available.

Uncertainty quantification for optical model parameters

DOE PAGES

Lovell, A. E.; Nunes, F. M.; Sarich, J.; ...

2017-02-21

Although uncertainty quantification has been making its way into nuclear theory, these methods have yet to be explored in the context of reaction theory. For example, it is well known that different parameterizations of the optical potential can result in different cross sections, but these differences have not been systematically studied and quantified. The purpose of our work is to investigate the uncertainties in nuclear reactions that result from fitting a given model to elastic-scattering data, as well as to study how these uncertainties propagate to the inelastic and transfer channels. We use statistical methods to determine a best fitmore » and create corresponding 95% confidence bands. A simple model of the process is fit to elastic-scattering data and used to predict either inelastic or transfer cross sections. In this initial work, we assume that our model is correct, and the only uncertainties come from the variation of the fit parameters. Here, we study a number of reactions involving neutron and deuteron projectiles with energies in the range of 5–25 MeV/u, on targets with mass A=12–208. We investigate the correlations between the parameters in the fit. The case of deuterons on 12C is discussed in detail: the elastic-scattering fit and the prediction of 12C(d,p) 13C transfer angular distributions, using both uncorrelated and correlated χ 2 minimization functions. The general features for all cases are compiled in a systematic manner to identify trends. This work shows that, in many cases, the correlated χ 2 functions (in comparison to the uncorrelated χ 2 functions) provide a more natural parameterization of the process. These correlated functions do, however, produce broader confidence bands. Further optimization may require improvement in the models themselves and/or more information included in the fit.« less

Engelmann Spruce Site Index Models: A Comparison of Model Functions and Parameterizations

PubMed Central

Nigh, Gordon

2015-01-01

Engelmann spruce (Picea engelmannii Parry ex Engelm.) is a high-elevation species found in western Canada and western USA. As this species becomes increasingly targeted for harvesting, better height growth information is required for good management of this species. This project was initiated to fill this need. The objective of the project was threefold: develop a site index model for Engelmann spruce; compare the fits and modelling and application issues between three model formulations and four parameterizations; and more closely examine the grounded-Generalized Algebraic Difference Approach (g-GADA) model parameterization. The model fitting data consisted of 84 stem analyzed Engelmann spruce site trees sampled across the Engelmann Spruce – Subalpine Fir biogeoclimatic zone. The fitted models were based on the Chapman-Richards function, a modified Hossfeld IV function, and the Schumacher function. The model parameterizations that were tested are indicator variables, mixed-effects, GADA, and g-GADA. Model evaluation was based on the finite-sample corrected version of Akaike’s Information Criteria and the estimated variance. Model parameterization had more of an influence on the fit than did model formulation, with the indicator variable method providing the best fit, followed by the mixed-effects modelling (9% increase in the variance for the Chapman-Richards and Schumacher formulations over the indicator variable parameterization), g-GADA (optimal approach) (335% increase in the variance), and the GADA/g-GADA (with the GADA parameterization) (346% increase in the variance). Factors related to the application of the model must be considered when selecting the model for use as the best fitting methods have the most barriers in their application in terms of data and software requirements. PMID:25853472

Two-Drug Antimicrobial Chemotherapy: A Mathematical Model and Experiments with Mycobacterium marinum

PubMed Central

Ankomah, Peter; Levin, Bruce R.

2012-01-01

Multi-drug therapy is the standard-of-care treatment for tuberculosis. Despite this, virtually all studies of the pharmacodynamics (PD) of mycobacterial drugs employed for the design of treatment protocols are restricted to single agents. In this report, mathematical models and in vitro experiments with Mycobacterium marinum and five antimycobacterial drugs are used to quantitatively evaluate the pharmaco-, population and evolutionary dynamics of two-drug antimicrobial chemotherapy regimes. Time kill experiments with single and pairs of antibiotics are used to estimate the parameters and evaluate the fit of Hill-function-based PD models. While Hill functions provide excellent fits for the PD of each single antibiotic studied, rifampin, amikacin, clarithromycin, streptomycin and moxifloxacin, two-drug Hill functions with a unique interaction parameter cannot account for the PD of any of the 10 pairs of these drugs. If we assume two antibiotic-concentration dependent functions for the interaction parameter, one for sub-MIC and one for supra-MIC drug concentrations, the modified biphasic Hill function provides a reasonably good fit for the PD of all 10 pairs of antibiotics studied. Monte Carlo simulations of antibiotic treatment based on the experimentally-determined PD functions are used to evaluate the potential microbiological efficacy (rate of clearance) and evolutionary consequences (likelihood of generating multi-drug resistance) of these different drug combinations as well as their sensitivity to different forms of non-adherence to therapy. These two-drug treatment simulations predict varying outcomes for the different pairs of antibiotics with respect to the aforementioned measures of efficacy. In summary, Hill functions with biphasic drug-drug interaction terms provide accurate analogs for the PD of pairs of antibiotics and M. marinum. The models, experimental protocols and computer simulations used in this study can be applied to evaluate the potential microbiological and evolutionary efficacy of two-drug therapy for any bactericidal antibiotics and bacteria that can be cultured in vitro. PMID:22253599

FITSManager: Management of Personal Astronomical Data

NASA Astrophysics Data System (ADS)

Cui, Chenzhou; Fan, Dongwei; Zhao, Yongheng; Kembhavi, Ajit; He, Boliang; Cao, Zihuang; Li, Jian; Nandrekar, Deoyani

2011-07-01

With the increase of personal storage capacity, it is easy to find hundreds to thousands of FITS files in the personal computer of an astrophysicist. Because Flexible Image Transport System (FITS) is a professional data format initiated by astronomers and used mainly in the small community, data management toolkits for FITS files are very few. Astronomers need a powerful tool to help them manage their local astronomical data. Although Virtual Observatory (VO) is a network oriented astronomical research environment, its applications and related technologies provide useful solutions to enhance the management and utilization of astronomical data hosted in an astronomer's personal computer. FITSManager is such a tool to provide astronomers an efficient management and utilization of their local data, bringing VO to astronomers in a seamless and transparent way. FITSManager provides fruitful functions for FITS file management, like thumbnail, preview, type dependent icons, header keyword indexing and search, collaborated working with other tools and online services, and so on. The development of the FITSManager is an effort to fill the gap between management and analysis of astronomical data.

Physical Fitness and Serum Vitamin D and Cognition in Elderly Koreans.

PubMed

Ahn, Jeong-Deok; Kang, Hyunsik

2015-12-01

Poor physical fitness and low serum vitamin D are known to be modifiable risk factors for cognitive declines with normal aging. We investigated the association of physical fitness and serum vitamin D levels with global cognitive function in older adults. In this cross-sectional study, a total of 412 older Korean adults (108 men aged 74.4 ± 6.0 years and 304 women aged 73.1 ± 5.4 years) completed the Korean version of Mini-Mental State Examination (MMSE) to assess global cognitive performance and the senior fitness test to assess strength, flexibility, agility, and endurance domains of physical fitness. Body mass index, percent body fat, serum vitamin D, geriatric depression scale (GDS), level of education, smoking, and history of cardiovascular or cerebrovascular disease were also assessed as covariates. Age, sex, GDS, and body fatness were negatively associated with MMSE-based cognitive performance. Serum vitamin D and physical fitness were positively associated with MMSE-based cognitive performance. Multivariate linear regression showed that agility (partial R(2) = -0.184, p = 0.029) and endurance (partial R(2) = 0.191, p = 0.022) domains of physical fitness along with serum vitamin D (partial R(2) = 0.210, p = 0.012) were significant predictors for global cognitive performance after controlling for covariates (i.e., age, sex, education, GDS, body fatness, and comorbidity index). The current findings of the study suggest that promotion of physical fitness and vitamin D supplementation should be key components of interventions to prevent cognitive decline with normal aging. Key pointsCognitive declines are associated with normal aging as well as modifiable lifestyle risk factors, and there is an increasing need to identify the modifiable risk factors for the onset of cognitive declines and to provide evidence-based strategies for healthy and successful aging.In Korea, little is known about the relationships of physical fitness and serum vitamin D with cognitive function in older adults, and we determined the associations between a) serum vitamin D levels and cognitive function and b) physical fitness and cognitive function among community-dwelling elderly Koreans.The current findings of the study suggest that agility and endurance domains of physical fitness along with serum vitamin D were significant predictors for global cognitive performance after controlling for covariates.

Physical Fitness and Serum Vitamin D and Cognition in Elderly Koreans

PubMed Central

Ahn, Jeong-Deok; Kang, Hyunsik

2015-01-01

Poor physical fitness and low serum vitamin D are known to be modifiable risk factors for cognitive declines with normal aging. We investigated the association of physical fitness and serum vitamin D levels with global cognitive function in older adults. In this cross-sectional study, a total of 412 older Korean adults (108 men aged 74.4 ± 6.0 years and 304 women aged 73.1 ± 5.4 years) completed the Korean version of Mini-Mental State Examination (MMSE) to assess global cognitive performance and the senior fitness test to assess strength, flexibility, agility, and endurance domains of physical fitness. Body mass index, percent body fat, serum vitamin D, geriatric depression scale (GDS), level of education, smoking, and history of cardiovascular or cerebrovascular disease were also assessed as covariates. Age, sex, GDS, and body fatness were negatively associated with MMSE-based cognitive performance. Serum vitamin D and physical fitness were positively associated with MMSE-based cognitive performance. Multivariate linear regression showed that agility (partial R2 = -0.184, p = 0.029) and endurance (partial R2 = 0.191, p = 0.022) domains of physical fitness along with serum vitamin D (partial R2 = 0.210, p = 0.012) were significant predictors for global cognitive performance after controlling for covariates (i.e., age, sex, education, GDS, body fatness, and comorbidity index). The current findings of the study suggest that promotion of physical fitness and vitamin D supplementation should be key components of interventions to prevent cognitive decline with normal aging. Key points Cognitive declines are associated with normal aging as well as modifiable lifestyle risk factors, and there is an increasing need to identify the modifiable risk factors for the onset of cognitive declines and to provide evidence-based strategies for healthy and successful aging. In Korea, little is known about the relationships of physical fitness and serum vitamin D with cognitive function in older adults, and we determined the associations between a) serum vitamin D levels and cognitive function and b) physical fitness and cognitive function among community-dwelling elderly Koreans. The current findings of the study suggest that agility and endurance domains of physical fitness along with serum vitamin D were significant predictors for global cognitive performance after controlling for covariates. PMID:26664270

Novel Mahalanobis-based feature selection improves one-class classification of early hepatocellular carcinoma.

PubMed

Thomaz, Ricardo de Lima; Carneiro, Pedro Cunha; Bonin, João Eliton; Macedo, Túlio Augusto Alves; Patrocinio, Ana Claudia; Soares, Alcimar Barbosa

2018-05-01

Detection of early hepatocellular carcinoma (HCC) is responsible for increasing survival rates in up to 40%. One-class classifiers can be used for modeling early HCC in multidetector computed tomography (MDCT), but demand the specific knowledge pertaining to the set of features that best describes the target class. Although the literature outlines several features for characterizing liver lesions, it is unclear which is most relevant for describing early HCC. In this paper, we introduce an unconstrained GA feature selection algorithm based on a multi-objective Mahalanobis fitness function to improve the classification performance for early HCC. We compared our approach to a constrained Mahalanobis function and two other unconstrained functions using Welch's t-test and Gaussian Data Descriptors. The performance of each fitness function was evaluated by cross-validating a one-class SVM. The results show that the proposed multi-objective Mahalanobis fitness function is capable of significantly reducing data dimensionality (96.4%) and improving one-class classification of early HCC (0.84 AUC). Furthermore, the results provide strong evidence that intensity features extracted at the arterial to portal and arterial to equilibrium phases are important for classifying early HCC.

Using Stocking or Harvesting to Reverse Period-Doubling Bifurcations in Discrete Population Models

Treesearch

James F. Selgrade

1998-01-01

This study considers a general class of 2-dimensional, discrete population models where each per capita transition function (fitness) depends on a linear combination of the densities of the interacting populations. The fitness functions are either monotone decreasing functions (pioneer fitnesses) or one-humped functions (climax fitnesses). Four sets of necessary...

Reversing Period-Doubling Bifurcations in Models of Population Interactions Using Constant Stocking or Harvesting

Treesearch

James F. Selgrade; James H. Roberds

1998-01-01

This study considers a general class of two-dimensional, discrete population models where each per capita transition function (fitness) depends on a linear combination of the densities of the interacting populations. The fitness functions are either monotone decreasing functions (pioneer fitnesses) or one-humped functions (climax fitnesses). Conditions are derived...

Effects of dust polarity and nonextensive electrons on the dust-ion acoustic solitons and double layers in earth atmosphere

NASA Astrophysics Data System (ADS)

Ghobakhloo, Marzieh; Zomorrodian, Mohammad Ebrahim; Javidan, Kurosh

2018-05-01

Propagation of dustion acoustic solitary waves (DIASWs) and double layers is discussed in earth atmosphere, using the Sagdeev potential method. The best model for distribution function of electrons in earth atmosphere is found by fitting available data on different distribution functions. The nonextensive function with parameter q = 0.58 provides the best fit on observations. Thus we analyze the propagation of localized waves in an unmagnetized plasma containing nonextensive electrons, inertial ions, and negatively/positively charged stationary dust. It is found that both compressive and rarefactive solitons as well as double layers exist depending on the sign (and the value) of dust polarity. Characters of propagated waves are described using the presented model.

Psi4 1.1: An Open-Source Electronic Structure Program Emphasizing Automation, Advanced Libraries, and Interoperability.

PubMed

Parrish, Robert M; Burns, Lori A; Smith, Daniel G A; Simmonett, Andrew C; DePrince, A Eugene; Hohenstein, Edward G; Bozkaya, Uğur; Sokolov, Alexander Yu; Di Remigio, Roberto; Richard, Ryan M; Gonthier, Jérôme F; James, Andrew M; McAlexander, Harley R; Kumar, Ashutosh; Saitow, Masaaki; Wang, Xiao; Pritchard, Benjamin P; Verma, Prakash; Schaefer, Henry F; Patkowski, Konrad; King, Rollin A; Valeev, Edward F; Evangelista, Francesco A; Turney, Justin M; Crawford, T Daniel; Sherrill, C David

2017-07-11

Psi4 is an ab initio electronic structure program providing methods such as Hartree-Fock, density functional theory, configuration interaction, and coupled-cluster theory. The 1.1 release represents a major update meant to automate complex tasks, such as geometry optimization using complete-basis-set extrapolation or focal-point methods. Conversion of the top-level code to a Python module means that Psi4 can now be used in complex workflows alongside other Python tools. Several new features have been added with the aid of libraries providing easy access to techniques such as density fitting, Cholesky decomposition, and Laplace denominators. The build system has been completely rewritten to simplify interoperability with independent, reusable software components for quantum chemistry. Finally, a wide range of new theoretical methods and analyses have been added to the code base, including functional-group and open-shell symmetry adapted perturbation theory, density-fitted coupled cluster with frozen natural orbitals, orbital-optimized perturbation and coupled-cluster methods (e.g., OO-MP2 and OO-LCCD), density-fitted multiconfigurational self-consistent field, density cumulant functional theory, algebraic-diagrammatic construction excited states, improvements to the geometry optimizer, and the "X2C" approach to relativistic corrections, among many other improvements.

OMFIT Tokamak Profile Data Fitting and Physics Analysis

DOE PAGES

Logan, N. C.; Grierson, B. A.; Haskey, S. R.; ...

2018-01-22

Here, One Modeling Framework for Integrated Tasks (OMFIT) has been used to develop a consistent tool for interfacing with, mapping, visualizing, and fitting tokamak profile measurements. OMFIT is used to integrate the many diverse diagnostics on multiple tokamak devices into a regular data structure, consistently applying spatial and temporal treatments to each channel of data. Tokamak data are fundamentally time dependent and are treated so from the start, with front-loaded and logic-based manipulations such as filtering based on the identification of edge-localized modes (ELMs) that commonly scatter data. Fitting is general in its approach, and tailorable in its application inmore » order to address physics constraints and handle the multiple spatial and temporal scales involved. Although community standard one-dimensional fitting is supported, including scale length–fitting and fitting polynomial-exponential blends to capture the H-mode pedestal, OMFITprofiles includes two-dimensional (2-D) fitting using bivariate splines or radial basis functions. These 2-D fits produce regular evolutions in time, removing jitter that has historically been smoothed ad hoc in transport applications. Profiles interface directly with a wide variety of models within the OMFIT framework, providing the inputs for TRANSP, kinetic-EFIT 2-D equilibrium, and GPEC three-dimensional equilibrium calculations. he OMFITprofiles tool’s rapid and comprehensive analysis of dynamic plasma profiles thus provides the critical link between raw tokamak data and simulations necessary for physics understanding.« less

OMFIT Tokamak Profile Data Fitting and Physics Analysis

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

Logan, N. C.; Grierson, B. A.; Haskey, S. R.

Here, One Modeling Framework for Integrated Tasks (OMFIT) has been used to develop a consistent tool for interfacing with, mapping, visualizing, and fitting tokamak profile measurements. OMFIT is used to integrate the many diverse diagnostics on multiple tokamak devices into a regular data structure, consistently applying spatial and temporal treatments to each channel of data. Tokamak data are fundamentally time dependent and are treated so from the start, with front-loaded and logic-based manipulations such as filtering based on the identification of edge-localized modes (ELMs) that commonly scatter data. Fitting is general in its approach, and tailorable in its application inmore » order to address physics constraints and handle the multiple spatial and temporal scales involved. Although community standard one-dimensional fitting is supported, including scale length–fitting and fitting polynomial-exponential blends to capture the H-mode pedestal, OMFITprofiles includes two-dimensional (2-D) fitting using bivariate splines or radial basis functions. These 2-D fits produce regular evolutions in time, removing jitter that has historically been smoothed ad hoc in transport applications. Profiles interface directly with a wide variety of models within the OMFIT framework, providing the inputs for TRANSP, kinetic-EFIT 2-D equilibrium, and GPEC three-dimensional equilibrium calculations. he OMFITprofiles tool’s rapid and comprehensive analysis of dynamic plasma profiles thus provides the critical link between raw tokamak data and simulations necessary for physics understanding.« less

The braking force in walking: age-related differences and improvement in older adults with exergame training.

PubMed

Maillot, Pauline; Perrot, Alexandra; Hartley, Alan; Do, Manh-Cuong

2014-10-01

The purposes of this present research were, in the first study, to determine whether age impacts a measure of postural control (the braking force in walking) and, in a second study, to determine whether exergame training in physically-simulated sport activity would show transfer, increasing the braking force in walking and also improving balance assessed by clinical measures, functional fitness, and health-related quality of life in older adults. For the second study, the authors developed an active video game training program (using the Wii system) with a pretest-training-posttest design comparing an experimental group (24 1-hr sessions of training) with a control group. Participants completed a battery comprising balance (braking force in short and normal step conditions), functional fitness (Senior Fitness Test), and health-related quality of life (SF-36). Results show that 12 weeks of video game-based exercise program training improved the braking force in the normal step condition, along with the functional fitness of lower limb strength, cardiovascular endurance, and motor agility, as measured by the Senior Fitness Test. Only the global mental dimension of the SF-36 was sensitive to exergame practice. Exergames appear to be an effective way to train postural control in older adults. Because of the multimodal nature of the activity, exergames provide an effective tool for remediation of age-related problems.

A determination of the fragmentation functions of pions, kaons, and protons with faithful uncertainties. The NNPDF Collaboration

NASA Astrophysics Data System (ADS)

Bertone, Valerio; Carrazza, Stefano; Hartland, Nathan P.; Nocera, Emanuele R.; Rojo, Juan

2017-08-01

We present NNFF1.0, a new determination of the fragmentation functions (FFs) of charged pions, charged kaons, and protons/antiprotons from an analysis of single-inclusive hadron production data in electron-positron annihilation. This determination, performed at leading, next-to-leading, and next-to-next-to-leading order in perturbative QCD, is based on the NNPDF methodology, a fitting framework designed to provide a statistically sound representation of FF uncertainties and to minimise any procedural bias. We discuss novel aspects of the methodology used in this analysis, namely an optimised parametrisation of FFs and a more efficient χ ^2 minimisation strategy, and validate the FF fitting procedure by means of closure tests. We then present the NNFF1.0 sets, and discuss their fit quality, their perturbative convergence, and their stability upon variations of the kinematic cuts and the fitted dataset. We find that the systematic inclusion of higher-order QCD corrections significantly improves the description of the data, especially in the small- z region. We compare the NNFF1.0 sets to other recent sets of FFs, finding in general a reasonable agreement, but also important differences. Together with existing sets of unpolarised and polarised parton distribution functions (PDFs), FFs and PDFs are now available from a common fitting framework for the first time.

Targeting functional fitness, hearing and health-related quality of life in older adults with hearing loss: Walk, Talk 'n' Listen, study protocol for a pilot randomized controlled trial.

PubMed

Lambert, Justin; Ghadry-Tavi, Rouzbeh; Knuff, Kate; Jutras, Marc; Siever, Jodi; Mick, Paul; Roque, Carolyn; Jones, Gareth; Little, Jonathan; Miller, Harry; Van Bergen, Colin; Kurtz, Donna; Murphy, Mary Ann; Jones, Charlotte Ann

2017-01-28

Hearing loss (HL) is a disability associated with poorer health-related quality of life including an increased risk for loneliness, isolation, functional fitness declines, falls, hospitalization and premature mortality. The purpose of this pilot trial is to determine the feasibility and acceptability of a novel intervention to reduce loneliness, improve functional fitness, social connectedness, hearing and health-related quality of life in older adults with HL. This 10-week, single-blind, pilot randomized control trial (RCT) will include a convenience sample of ambulatory adults aged 65 years or older with self-reported HL. Following baseline assessments, participants will be randomized to either intervention (exercise, health education, socialization and group auditory rehabilitation (GAR)) or control (GAR only) groups. The intervention group will attend a local YMCA twice a week and the control group once a week. Intervention sessions will include 45 min of strengthening, balance and resistance exercises, 30 min of group walking at a self-selected pace and 60 min of interactive health education or GAR. The control group will attend 60-min GAR sessions. GAR sessions will include education about hearing, hearing technologies, enhancing communication skills, and psychosocial support. Pre-post trial data collection and measures will include: functional fitness (gait speed, 30-s Sit to Stand Test), hearing and health-related quality of life, loneliness, depression, social participation and social support. At trial end, feasibility (recruitment, randomization, retention, acceptability) and GAR will be evaluated. Despite evidence suggesting that HL is associated with declines in functional fitness, there are no studies aimed at addressing functional fitness declines associated with the disability of HL. This pilot trial will provide knowledge about the physical, mental and social impacts on health related to HL as a disability. This will inform the feasibility of a larger RCT and preliminary evidence about the initial effects of a novel, community-based, holistic intervention addressing both the negative psychosocial and functional physical effects of HL among older adults. ClinicalTrials.gov, NCT02662192 . Registered on 14 January 2016.

Data from fitting Gaussian process models to various data sets using eight Gaussian process software packages.

PubMed

Erickson, Collin B; Ankenman, Bruce E; Sanchez, Susan M

2018-06-01

This data article provides the summary data from tests comparing various Gaussian process software packages. Each spreadsheet represents a single function or type of function using a particular input sample size. In each spreadsheet, a row gives the results for a particular replication using a single package. Within each spreadsheet there are the results from eight Gaussian process model-fitting packages on five replicates of the surface. There is also one spreadsheet comparing the results from two packages performing stochastic kriging. These data enable comparisons between the packages to determine which package will give users the best results.

Spot quantification in two dimensional gel electrophoresis image analysis: comparison of different approaches and presentation of a novel compound fitting algorithm

PubMed Central

2014-01-01

Background Various computer-based methods exist for the detection and quantification of protein spots in two dimensional gel electrophoresis images. Area-based methods are commonly used for spot quantification: an area is assigned to each spot and the sum of the pixel intensities in that area, the so-called volume, is used a measure for spot signal. Other methods use the optical density, i.e. the intensity of the most intense pixel of a spot, or calculate the volume from the parameters of a fitted function. Results In this study we compare the performance of different spot quantification methods using synthetic and real data. We propose a ready-to-use algorithm for spot detection and quantification that uses fitting of two dimensional Gaussian function curves for the extraction of data from two dimensional gel electrophoresis (2-DE) images. The algorithm implements fitting using logical compounds and is computationally efficient. The applicability of the compound fitting algorithm was evaluated for various simulated data and compared with other quantification approaches. We provide evidence that even if an incorrect bell-shaped function is used, the fitting method is superior to other approaches, especially when spots overlap. Finally, we validated the method with experimental data of urea-based 2-DE of Aβ peptides andre-analyzed published data sets. Our methods showed higher precision and accuracy than other approaches when applied to exposure time series and standard gels. Conclusion Compound fitting as a quantification method for 2-DE spots shows several advantages over other approaches and could be combined with various spot detection methods. The algorithm was scripted in MATLAB (Mathworks) and is available as a supplemental file. PMID:24915860

Clinical and multiple gene expression variables in survival analysis of breast cancer: Analysis with the hypertabastic survival model

PubMed Central

2012-01-01

Background We explore the benefits of applying a new proportional hazard model to analyze survival of breast cancer patients. As a parametric model, the hypertabastic survival model offers a closer fit to experimental data than Cox regression, and furthermore provides explicit survival and hazard functions which can be used as additional tools in the survival analysis. In addition, one of our main concerns is utilization of multiple gene expression variables. Our analysis treats the important issue of interaction of different gene signatures in the survival analysis. Methods The hypertabastic proportional hazards model was applied in survival analysis of breast cancer patients. This model was compared, using statistical measures of goodness of fit, with models based on the semi-parametric Cox proportional hazards model and the parametric log-logistic and Weibull models. The explicit functions for hazard and survival were then used to analyze the dynamic behavior of hazard and survival functions. Results The hypertabastic model provided the best fit among all the models considered. Use of multiple gene expression variables also provided a considerable improvement in the goodness of fit of the model, as compared to use of only one. By utilizing the explicit survival and hazard functions provided by the model, we were able to determine the magnitude of the maximum rate of increase in hazard, and the maximum rate of decrease in survival, as well as the times when these occurred. We explore the influence of each gene expression variable on these extrema. Furthermore, in the cases of continuous gene expression variables, represented by a measure of correlation, we were able to investigate the dynamics with respect to changes in gene expression. Conclusions We observed that use of three different gene signatures in the model provided a greater combined effect and allowed us to assess the relative importance of each in determination of outcome in this data set. These results point to the potential to combine gene signatures to a greater effect in cases where each gene signature represents some distinct aspect of the cancer biology. Furthermore we conclude that the hypertabastic survival models can be an effective survival analysis tool for breast cancer patients. PMID:23241496

A clinical study to evaluate denture adhesive use in well-fitting dentures.

PubMed

Munoz, Carlos A; Gendreau, Linda; Shanga, Gilbert; Magnuszewski, Tabetha; Fernandez, Patricia; Durocher, John

2012-02-01

The objective of this study was the assessment of retention and stability and functional benefits of denture adhesive applied to well-fitting and well-made dentures. This was a randomized, crossover study to compare two marketed denture adhesives (test cream, Super Poligrip® Free, and test strip, Super Poligrip® Comfort Seal Strips) and an unmarketed cream adhesive (GlaxoSmith Kline Consumer Healthcare) with no adhesive as the negative control. Thirty-six subjects completed the study. One hour after the application of denture adhesive, retention and stability were measured using the Kapur Index and maxillary incisal bite force. Two hours after application, functional tests were used to assess denture movement and peanut particle migration under the denture. Subjects also rated confidence, comfort, satisfaction with dentures, and denture wobble in conjunction with the functional tests. Denture adhesives significantly (p < 0.05) improved retention and stability of well-fitting dentures. Subjects experienced significantly (p < 0.05) fewer dislodgements while eating an apple after adhesive was applied to dentures. Significant (p < 0.05) increases in subjective ratings of confidence and comfort as well as decreases in denture wobble were associated with the use of adhesive. There was significant (p < 0.05) improvement in satisfaction ratings for cream adhesives. A single application of each denture adhesive was well tolerated. The results of this study provide evidence that use of Super Poligrip® denture adhesives can enhance aspects of performance of complete well-fitting dentures as well as provide increased comfort, confidence, and satisfaction with dentures. © 2011 by the American College of Prosthodontists.

Conceptualization of the Sexual Response Models in Men: Are there Differences Between Sexually Functional and Dysfunctional Men?

PubMed

Connaughton, Catherine; McCabe, Marita; Karantzas, Gery

2016-03-01

Research to validate models of sexual response empirically in men with and without sexual dysfunction (MSD), as currently defined, is limited. To explore the extent to which the traditional linear or the Basson circular model best represents male sexual response for men with MSD and sexually functional men. In total, 573 men completed an online questionnaire to assess sexual function and aspects of the models of sexual response. In total, 42.2% of men (242) were sexually functional, and 57.8% (331) had at least one MSD. Models were built and tested using bootstrapping and structural equation modeling. Fit of models for men with and without MSD. The linear model and the initial circular model were a poor fit for men with and without MSD. A modified version of the circular model demonstrated adequate fit for the two groups and showed important interactions between psychological factors and sexual response for men with and without MSD. Male sexual response was not represented by the linear model for men with or without MSD, excluding possible healthy responsive desire. The circular model provided a better fit for the two groups of men but demonstrated that the relations between psychological factors and phases of sexual response were different for men with and without MSD as currently defined. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Functional training improves club head speed and functional fitness in older golfers.

PubMed

Thompson, Christian J; Cobb, Karen Myers; Blackwell, John

2007-02-01

Functional training programs have been used in a variety of rehabilitation settings with documented success. Based on that success, the concept of functional training has gained popularity in applied fitness settings to enhance sport performance. However, there has been little or no research studying the efficacy of functional training programs on the improvement of sport performance or functional fitness. Thus, it was the purpose of this study to determine the effect of a progressive functional training program on club head speed and functional fitness in older male golfers. Eighteen male golfers (age: 70.7 +/- 9.1 [SD] years) were randomly assigned to an exercise (N = 11) or control (N = 7) group. The exercise group participated in an 8-week progressive functional training program including flexibility exercises, core stability exercises, balance exercises, and resistance exercises. Pre- and postmeasurements included club head speed of a driver by radar (exercise and Control) and Fullerton Senior Fitness Test measurements (exercise only). One-way analysis of covariance was performed on club head speed measurements using pretest measurements as the covariate. Paired t-tests were performed to analyze Senior Fitness Test variables. After the intervention, maximal club head speed increased in the exercise group (127.3 +/- 13.4 to 133.6 +/- 14.2 km x hr(-1)) compared with the control group (134.5 +/- 14.6 to 133.3 +/- 11.2 km x hr(-1); p < 0.05). Additionally, improvements (p < 0.05) were detected for most Senior Fitness Test variables in the exercise group. In summary, this functional training program resulted in significant improvements in club head speed and several components of functional fitness. Future research should continue to examine the effect of functional training programs on sport performance and functional fitness in older adults.

Alzheimer Disease Alters the Relationship of Cardiorespiratory Fitness With Brain Activity During the Stroop Task

PubMed Central

Gayed, Matthew R.; Honea, Robyn A.; Savage, Cary R.; Hobbs, Derek; Burns, Jeffrey M.

2013-01-01

Background Despite mounting evidence that physical activity has positive benefits for brain and cognitive health, there has been little characterization of the relationship between cardiorespiratory (CR) fitness and cognition-associated brain activity as measured by functional magnetic resonance imaging (fMRI). The lack of evidence is particularly glaring for diseases such as Alzheimer disease (AD) that degrade cognitive and functional performance. Objective The aim of this study was to describe the relationship between regional brain activity during cognitive tasks and CR fitness level in people with and without AD. Design A case-control, single-observation study design was used. Methods Thirty-four individuals (18 without dementia and 16 in the earliest stages of AD) completed maximal exercise testing and performed a Stroop task during fMRI. Results Cardiorespiratory fitness was inversely associated with anterior cingulate activity in the participants without dementia (r=−.48, P=.05) and unassociated with activation in those with AD (P>.7). Weak associations of CR fitness and middle frontal cortex were noted. Limitations The wide age range and the use of a single task in fMRI rather than multiple tasks challenging different cognitive capacities were limitations of the study. Conclusions The results offer further support of the relationship between CR fitness and regional brain activity. However, this relationship may be attenuated by disease. Future work in this area may provide clinicians and researchers with interpretable and dependable regional fMRI biomarker signatures responsive to exercise intervention. It also may shed light on mechanisms by which exercise can support cognitive function. PMID:23559521

Task-oriented treadmill exercise training in chronic hemiparetic stroke

PubMed Central

Ivey, Frederick M.; Hafer-Macko, Charlene E.; Macko, Richard F.

2010-01-01

Patients with stroke have elevated hemiparetic gait costs secondary to low activity levels and are often severely deconditioned. Decrements in peak aerobic capacity affect functional ability and cardiovascular-metabolic health and may be partially mediated by molecular changes in hemiparetic skeletal muscle. Conventional rehabilitation is time delimited in the subacute stroke phase and does not provide adequate aerobic intensity to reverse the profound detriments to fitness and function that result from stroke. Hence, we have studied progressive full body weight-support treadmill (TM) training as an adjunct therapy in the chronic stroke phase. Task-oriented TM training has produced measurable changes in fitness, function, and indices of cardiovascular-metabolic health after stroke, but the precise mechanisms for these changes remain under investigation. Further, the optimal dose of this therapy has yet to be identified for individuals with stroke and may vary as a function of deficit severity and outcome goals. This article summarizes the functional and metabolic decline caused by inactivity after stroke and provides current evidence that supports the use of TM training during the chronic stroke phase, with protocols and inclusion/exclusion criteria described. Our research findings are discussed in relation to associated research. PMID:18566943

Estimation of time- and state-dependent delays and other parameters in functional differential equations

NASA Technical Reports Server (NTRS)

Murphy, K. A.

1988-01-01

A parameter estimation algorithm is developed which can be used to estimate unknown time- or state-dependent delays and other parameters (e.g., initial condition) appearing within a nonlinear nonautonomous functional differential equation. The original infinite dimensional differential equation is approximated using linear splines, which are allowed to move with the variable delay. The variable delays are approximated using linear splines as well. The approximation scheme produces a system of ordinary differential equations with nice computational properties. The unknown parameters are estimated within the approximating systems by minimizing a least-squares fit-to-data criterion. Convergence theorems are proved for time-dependent delays and state-dependent delays within two classes, which say essentially that fitting the data by using approximations will, in the limit, provide a fit to the data using the original system. Numerical test examples are presented which illustrate the method for all types of delay.

Estimation of time- and state-dependent delays and other parameters in functional differential equations

NASA Technical Reports Server (NTRS)

Murphy, K. A.

1990-01-01

A parameter estimation algorithm is developed which can be used to estimate unknown time- or state-dependent delays and other parameters (e.g., initial condition) appearing within a nonlinear nonautonomous functional differential equation. The original infinite dimensional differential equation is approximated using linear splines, which are allowed to move with the variable delay. The variable delays are approximated using linear splines as well. The approximation scheme produces a system of ordinary differential equations with nice computational properties. The unknown parameters are estimated within the approximating systems by minimizing a least-squares fit-to-data criterion. Convergence theorems are proved for time-dependent delays and state-dependent delays within two classes, which say essentially that fitting the data by using approximations will, in the limit, provide a fit to the data using the original system. Numerical test examples are presented which illustrate the method for all types of delay.

Optimal retraining time for regaining functional fitness using multicomponent training after long-term detraining in older adults.

PubMed

Lee, Minyoung; Lim, Taehyun; Lee, Jaehyuk; Kim, Kimyeong; Yoon, BumChul

2017-11-01

Little is known about the optimal retraining time for regaining functional fitness through multicomponent training following long-term detraining in older adults. This study first investigated the time course of functional fitness changes during 12-month multicomponent training, 12-month detraining, and 9-month retraining in 18 older adults (68.33±3.46) and then determined the optimal retraining time for regaining the post-training functional fitness level after a 12-month detraining period. Functional fitness, including lower and upper limb strength, lower and upper limb flexibility, aerobic endurance, and dynamic balance, was assessed at baseline, 12 months post-training, 12 months post-detraining, and 3, 6, and 9 months post-retraining. There were significant increases in all of the functional fitness components except upper limb flexibility at post-training and no significant decreases at post-detraining. For lower and upper limb strength and lower limb flexibility, a 3-month period was required to regain the post-training condition. For aerobic endurance and dynamic balance, a retraining period ≥9months was necessary to regain the post-training functional fitness condition. To regain the post-training condition of all functional fitness components, a retraining period ≥9months was required. This information might be useful for health professionals to encourage older adults not to interrupt retraining until they regain their post-training functional fitness condition. Copyright © 2017 Elsevier B.V. All rights reserved.

Oscillation mechanics of the respiratory system.

PubMed

Bates, Jason H T; Irvin, Charles G; Farré, Ramon; Hantos, Zoltán

2011-07-01

The mechanical impedance of the respiratory system defines the pressure profile required to drive a unit of oscillatory flow into the lungs. Impedance is a function of oscillation frequency, and is measured using the forced oscillation technique. Digital signal processing methods, most notably the Fourier transform, are used to calculate impedance from measured oscillatory pressures and flows. Impedance is a complex function of frequency, having both real and imaginary parts that vary with frequency in ways that can be used empirically to distinguish normal lung function from a variety of different pathologies. The most useful diagnostic information is gained when anatomically based mathematical models are fit to measurements of impedance. The simplest such model consists of a single flow-resistive conduit connecting to a single elastic compartment. Models of greater complexity may have two or more compartments, and provide more accurate fits to impedance measurements over a variety of different frequency ranges. The model that currently enjoys the widest application in studies of animal models of lung disease consists of a single airway serving an alveolar compartment comprising tissue with a constant-phase impedance. This model has been shown to fit very accurately to a wide range of impedance data, yet contains only four free parameters, and as such is highly parsimonious. The measurement of impedance in human patients is also now rapidly gaining acceptance, and promises to provide a more comprehensible assessment of lung function than parameters derived from conventional spirometry. © 2011 American Physiological Society.

Schedule-induced drinking: rate of food delivery and Herrnstein's equation.

PubMed Central

Wetherington, C L

1979-01-01

Schedule-induced drinking was measured in four rats exposed to fixed-time schedules of food ranging from 30 to 480 seconds. Herrnstein's (1970, 1974) equation relating rate of a single response as a hyperbolic function of reinforcement rate provided a good fit to three measures of drinking: lick rate, ingestion rate, and relative time spent drinking. The functions relating the three measures of drinking to reinforcement rate were of similar form. Herrnstein's equation also provided a good description of some already published data on schedule-induced drinking. The fit both to the present data and to the already published data was improved somewhat by computing the measures by subtracting from the time base a latency constant representing the minimal time required to consume the food pellet and travel to the water source. The data from this study provide two correspondences between operant behavior and schedule-induced behavior: (a) conformity to Herrnstein's equation and (b) equivalence of rate and relative time measures. PMID:512568

On the Methodology of Studying Aging in Humans

DTIC Science & Technology

1961-01-01

prediction of death rates The relation of death rate to age has been extensively studied for over 100 years. As an illustration recent death rates for...log death rates appear to be linear, the simpler Gompertz curve fits closely. While on this subject of the Makeham-Gompertz function, it should be...Makeham-Gompertz curve to 5 year age specific death rates . Each fitting provided estimates of the parameters a, {j, and log c for each of the five year

Effect of balance training in older adults using Wii fit plus.

PubMed

Afridi, Ayesha; Malik, Arshad Nawaz; Ali, Shaukat; Amjad, Imran

2018-03-01

The Nintendo Wii-fit plus is a type of Virtual Reality exer-gaming with graphical and auditory response system. A case series was conducted at Shifa Tamer-e-Millat University Islamabad from January-July 2016. Sixteen adults more than 60 years age (07 males and 09 females) were recruited through convenient sampling. The specified Wii fit plus training was provided to all patients and the games included the Soccer heading, Ski slalom, table tilt and yoga. Berg balance test, time up and go and functional reach test were used before and after 06 weeks of treatment (4 days / week). Data was analysed by SPSS V-20. The mean age of the sample was 67.56±7.29 years, with 56% female and 44% males were in sample. There was a statistically significant difference in pre and post Berg Balance Score, time up and go test and functional reach. In this case series Wii-fit plus training was effective in improving dynamic balance and mobility in older adults. This should be explored further in large trials.

Incidence, severity, and impact of hyperhidrosis in people with lower-limb amputation.

PubMed

Hansen, Colby; Godfrey, Bradeigh; Wixom, Jody; McFadden, Molly

2015-01-01

To assess the incidence and severity of self-reported hyperhidrosis in patients with amputation and understand its effects on prosthetic fit or function, a cross-sectional survey of patients at two amputee clinics was performed. Responses from 121 subjects with lower-limb amputation were analyzed. Of these subjects, 66% reported sweating to a degree that it interfered with daily activities, as measured by the Hyperhidrosis Disease Severity Scale. There was a significant association between sweating and interference with prosthetic fit and function. Sweating was more severe in cases of transtibial amputations, patients under the age of 60, warm weather, and vigorous activity. There was no relationship between severity of sweating and time since amputation, etiology of amputation, duration of daily prosthetic use, or reported ability to perform functional tasks. Subjects reported trying multiple interventions, but the self-reported effectiveness of these treatments was low. Hyperhidrosis, a common problem associated with prosthetic usage, varies in severity and often interferes with daily activities. Sweating severity is associated with poor prosthetic fit and function. Risk factors include younger age and transtibial amputation status. Treatment strategies generally lack efficacy. The results of this study may provide guidance for future interventions and treatment options.

Use of Opioid Medications for Employees in Critical Safety or Security Positions and Positions with Safety Sensitive Duties

DTIC Science & Technology

2017-01-30

workers function while on the job must be thoroughly evaluated by a competent healthcare provider and fitness for duty must be determined. Treatment...performance of job functions with or without accommodation. D. Prior to recommending an employee’s return to a safety sensitive position, the healthcare

Mathematical functions for predicting growth and yield of black walnut plantations in the Central States.

Treesearch

Raymond S. Ferrell; Allen L. Lundgren

1976-01-01

Mathematical functions were fitted to unpublished summaries of yield data collected and reported by L.F. Kellogg in 1940 for unmanaged black walnut plantations in the Central States. They cover a wide range of conditions and provide the best data base available for simulating growth and yield in plantations.

A discrete spectral analysis for determining quasi-linear viscoelastic properties of biological materials

PubMed Central

Babaei, Behzad; Abramowitch, Steven D.; Elson, Elliot L.; Thomopoulos, Stavros; Genin, Guy M.

2015-01-01

The viscoelastic behaviour of a biological material is central to its functioning and is an indicator of its health. The Fung quasi-linear viscoelastic (QLV) model, a standard tool for characterizing biological materials, provides excellent fits to most stress–relaxation data by imposing a simple form upon a material's temporal relaxation spectrum. However, model identification is challenging because the Fung QLV model's ‘box’-shaped relaxation spectrum, predominant in biomechanics applications, can provide an excellent fit even when it is not a reasonable representation of a material's relaxation spectrum. Here, we present a robust and simple discrete approach for identifying a material's temporal relaxation spectrum from stress–relaxation data in an unbiased way. Our ‘discrete QLV’ (DQLV) approach identifies ranges of time constants over which the Fung QLV model's typical box spectrum provides an accurate representation of a particular material's temporal relaxation spectrum, and is effective at providing a fit to this model. The DQLV spectrum also reveals when other forms or discrete time constants are more suitable than a box spectrum. After validating the approach against idealized and noisy data, we applied the methods to analyse medial collateral ligament stress–relaxation data and identify the strengths and weaknesses of an optimal Fung QLV fit. PMID:26609064

Swimming and Children with Attention-Deficit Hyperactive Disorder: A Winning Combination

ERIC Educational Resources Information Center

Dail, Teresa; Smith, Caroline

2016-01-01

The benefits of swimming for children with disabilities include improved motor skills, physical fitness, executive brain function and improved social skills. Swimming can also be an activity that provides a positive environment for children suffering from attention-deficit hyperactive disorder (ADHD). This article provides an overview of ADHD and…

Definition of Unfit for Standard Acute Myeloid Leukemia Therapy.

PubMed

Klepin, Heidi D

2016-12-01

Determining who is fit or unfit for standard treatments among older adults with acute myeloid leukemia (AML) remains a challenge. However, available evidence can provide guidance on strategies to assess and categorize fitness. Evidence is strongest to guide identification of "frail" older adults at the time of diagnosis based on performance status, physical function, and comorbidity. Many older adults, with adequate performance status and comorbidity burden, however, may be better characterized as "vulnerable". These patients have subclinical impairments that limit resilience when stressed with intensive therapies. More sensitive assessment strategies are needed to differentiate fit and vulnerable older adults regardless of chronologic age. Research is ongoing to identify tools and approaches, such as geriatric assessment, that can enhance characterization of fitness for AML therapies. This review will highlight available evidence for assessment of fitness among older adults with AML and discuss implications for practice and research.

Genome-Enabled Modeling of Biogeochemical Processes Predicts Metabolic Dependencies that Connect the Relative Fitness of Microbial Functional Guilds

NASA Astrophysics Data System (ADS)

Brodie, E.; King, E.; Molins, S.; Karaoz, U.; Steefel, C. I.; Banfield, J. F.; Beller, H. R.; Anantharaman, K.; Ligocki, T. J.; Trebotich, D.

2015-12-01

Pore-scale processes mediated by microorganisms underlie a range of critical ecosystem services, regulating carbon stability, nutrient flux, and the purification of water. Advances in cultivation-independent approaches now provide us with the ability to reconstruct thousands of genomes from microbial populations from which functional roles may be assigned. With this capability to reveal microbial metabolic potential, the next step is to put these microbes back where they belong to interact with their natural environment, i.e. the pore scale. At this scale, microorganisms communicate, cooperate and compete across their fitness landscapes with communities emerging that feedback on the physical and chemical properties of their environment, ultimately altering the fitness landscape and selecting for new microbial communities with new properties and so on. We have developed a trait-based model of microbial activity that simulates coupled functional guilds that are parameterized with unique combinations of traits that govern fitness under dynamic conditions. Using a reactive transport framework, we simulate the thermodynamics of coupled electron donor-acceptor reactions to predict energy available for cellular maintenance, respiration, biomass development, and enzyme production. From metagenomics, we directly estimate some trait values related to growth and identify the linkage of key traits associated with respiration and fermentation, macromolecule depolymerizing enzymes, and other key functions such as nitrogen fixation. Our simulations were carried out to explore abiotic controls on community emergence such as seasonally fluctuating water table regimes across floodplain organic matter hotspots. Simulations and metagenomic/metatranscriptomic observations highlighted the many dependencies connecting the relative fitness of functional guilds and the importance of chemolithoautotrophic lifestyles. Using an X-Ray microCT-derived soil microaggregate physical model combined with genome-enabled reactive flow and transport we simulated the importance of pore network properties including connectivity in regulating metabolic interdependencies between microbial functional guilds.

Convergent functional genomics of psychiatric disorders.

PubMed

Niculescu, Alexander B

2013-10-01

Genetic and gene expression studies, in humans and animal models of psychiatric and other medical disorders, are becoming increasingly integrated. Particularly for genomics, the convergence and integration of data across species, experimental modalities and technical platforms is providing a fit-to-disease way of extracting reproducible and biologically important signal, in contrast to the fit-to-cohort effect and limited reproducibility of human genetic analyses alone. With the advent of whole-genome sequencing and the realization that a major portion of the non-coding genome may contain regulatory variants, Convergent Functional Genomics (CFG) approaches are going to be essential to identify disease-relevant signal from the tremendous polymorphic variation present in the general population. Such work in psychiatry can provide an example of how to address other genetically complex disorders, and in turn will benefit by incorporating concepts from other areas, such as cancer, cardiovascular diseases, and diabetes. © 2013 Wiley Periodicals, Inc.

A modeling framework for deriving the structural and functional architecture of a short-term memory microcircuit.

PubMed

Fisher, Dimitry; Olasagasti, Itsaso; Tank, David W; Aksay, Emre R F; Goldman, Mark S

2013-09-04

Although many studies have identified neural correlates of memory, relatively little is known about the circuit properties connecting single-neuron physiology to behavior. Here we developed a modeling framework to bridge this gap and identify circuit interactions capable of maintaining short-term memory. Unlike typical studies that construct a phenomenological model and test whether it reproduces select aspects of neuronal data, we directly fit the synaptic connectivity of an oculomotor memory circuit to a broad range of anatomical, electrophysiological, and behavioral data. Simultaneous fits to all data, combined with sensitivity analyses, revealed complementary roles of synaptic and neuronal recruitment thresholds in providing the nonlinear interactions required to generate the observed circuit behavior. This work provides a methodology for identifying the cellular and synaptic mechanisms underlying short-term memory and demonstrates how the anatomical structure of a circuit may belie its functional organization. Copyright © 2013 Elsevier Inc. All rights reserved.

Exploring the relations among physical fitness, executive functioning, and low academic achievement.

PubMed

de Bruijn, A G M; Hartman, E; Kostons, D; Visscher, C; Bosker, R J

2018-03-01

Physical fitness seems to be related to academic performance, at least when taking the role of executive functioning into account. This assumption is highly relevant for the vulnerable population of low academic achievers because their academic performance might benefit from enhanced physical fitness. The current study examined whether physical fitness and executive functioning are independent predictors of low mathematics and spelling achievement or whether the relation between physical fitness and low achievement is mediated by specific executive functions. In total, 477 students from second- and third-grade classes of 12 primary schools were classified as either low or average-to-high achievers in mathematics and spelling based on their scores on standardized achievement tests. Multilevel structural equation models were built with direct paths between physical fitness and academic achievement and added indirect paths via components of executive functioning: inhibition, verbal working memory, visuospatial working memory, and shifting. Physical fitness was only indirectly related to low achievement via specific executive functions, depending on the academic domain involved. Verbal working memory was a mediator between physical fitness and low achievement in both domains, whereas visuospatial working memory had a mediating role only in mathematics. Physical fitness interventions aiming to improve low academic achievement, thus, could potentially be successful. The mediating effect of executive functioning suggests that these improvements in academic achievement will be preceded by enhanced executive functions, either verbal working memory (in spelling) or both verbal and visuospatial working memory (in mathematics). Copyright © 2017 Elsevier Inc. All rights reserved.

Multiscale Models of Melting Arctic Sea Ice

DTIC Science & Technology

2014-09-30

from weakly to highly correlated, or Poissonian toward Wigner -Dyson, as a function of system connectedness. This provides a mechanism for explaining...eluded us. Court Strong found such a method. It creates an optimal fit of a hyperbolic tangent model for the fractal dimension as a function of log A...actual melt pond images, and have made significant advances in the underlying functional and numerical analysis needed for these computations

A comparison of Redlich-Kister polynomial and cubic spline representations of the chemical potential in phase field computations

DOE PAGES

Teichert, Gregory H.; Gunda, N. S. Harsha; Rudraraju, Shiva; ...

2016-12-18

Free energies play a central role in many descriptions of equilibrium and non-equilibrium properties of solids. Continuum partial differential equations (PDEs) of atomic transport, phase transformations and mechanics often rely on first and second derivatives of a free energy function. The stability, accuracy and robustness of numerical methods to solve these PDEs are sensitive to the particular functional representations of the free energy. In this communication we investigate the influence of different representations of thermodynamic data on phase field computations of diffusion and two-phase reactions in the solid state. First-principles statistical mechanics methods were used to generate realistic free energymore » data for HCP titanium with interstitially dissolved oxygen. While Redlich-Kister polynomials have formed the mainstay of thermodynamic descriptions of multi-component solids, they require high order terms to fit oscillations in chemical potentials around phase transitions. Here, we demonstrate that high fidelity fits to rapidly fluctuating free energy functions are obtained with spline functions. As a result, spline functions that are many degrees lower than Redlich-Kister polynomials provide equal or superior fits to chemical potential data and, when used in phase field computations, result in solution times approaching an order of magnitude speed up relative to the use of Redlich-Kister polynomials.« less

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.

Using a Non-Fit Message Helps to De-Intensify Negative Reactions to Tough Advice.

PubMed

Fridman, Ilona; Scherr, Karen A; Glare, Paul A; Higgins, E Tory

2016-08-01

Sometimes physicians need to provide patients with potentially upsetting advice. For example, physicians may recommend hospice for a terminally ill patient because it best meets their needs, but the patient and their family dislike this advised option. We explore whether regulatory non-fit could be used to improve these types of situations. Across five studies in which participants imagined receiving upsetting advice from a physician, we demonstrate that regulatory non-fit between the form of the physician's advice (emphasizing gains vs. avoiding losses) and the participants' motivational orientation (promotion vs. prevention) improves participants' evaluation of an initially disliked option. Regulatory non-fit de-intensifies participants' initial attitudes by making them less confident in their initial judgments and motivating them to think more thoroughly about the arguments presented. Furthermore, consistent with previous research on regulatory fit, we showed that the mechanism of regulatory non-fit differs as a function of participants' cognitive involvement in the evaluation of the option. © 2016 by the Society for Personality and Social Psychology, Inc.

Using a Non-Fit Message Helps to De-Intensify Negative Reactions to Tough Advice

PubMed Central

Fridman, Ilona; Scherr, Karen; Glare, Paul; Higgins, E. Tory

2017-01-01

Sometimes physicians need to provide patients with potentially upsetting advice. For example, physicians may recommend hospice for a terminally ill patient because it best meets their needs, but the patient and their family dislike this advised option. We explore whether regulatory non-fit could be used to improve these types of situations. Across five studies in which participants imagined receiving upsetting advice from a physician, we demonstrate that regulatory non-fit between the form of the physician’s advice (emphasizing gains vs. avoiding losses) and the participants’ motivational orientation (promotion vs. prevention) improves participants’ evaluation of an initially disliked option. Regulatory non-fit de-intensifies participants’ initial attitudes by making them less confident in their initial judgments and motivating them to think more thoroughly about the arguments presented. Furthermore, consistent with previous research on regulatory fit, we showed that the mechanism of regulatory non-fit differs as a function of participants’ cognitive involvement in the evaluation of the option. PMID:27341845

Improving Kepler Pipeline Sensitivity with Pixel Response Function Photometry.

NASA Astrophysics Data System (ADS)

Morris, Robert L.; Bryson, Steve; Jenkins, Jon Michael; Smith, Jeffrey C

2014-06-01

We present the results of our investigation into the feasibility and expected benefits of implementing PRF-fitting photometry in the Kepler Science Processing Pipeline. The Kepler Pixel Response Function (PRF) describes the expected system response to a point source at infinity and includes the effects of the optical point spread function, the CCD detector responsivity function, and spacecraft pointing jitter. Planet detection in the Kepler pipeline is currently based on simple aperture photometry (SAP), which is most effective when applied to uncrowded bright stars. Its effectiveness diminishes rapidly as target brightness decreases relative to the effects of noise sources such as detector electronics, background stars, and image motion. In contrast, PRF photometry is based on fitting an explicit model of image formation to the data and naturally accounts for image motion and contributions of background stars. The key to obtaining high-quality photometry from PRF fitting is a high-quality model of the system's PRF, while the key to efficiently processing the large number of Kepler targets is an accurate catalog and accurate mapping of celestial coordinates onto the focal plane. If the CCD coordinates of stellar centroids are known a priori then the problem of PRF fitting becomes linear. A model of the Kepler PRF was constructed at the time of spacecraft commissioning by fitting piecewise polynomial surfaces to data from dithered full frame images. While this model accurately captured the initial state of the system, the PRF has evolved dynamically since then and has been seen to deviate significantly from the initial (static) model. We construct a dynamic PRF model which is then used to recover photometry for all targets of interest. Both simulation tests and results from Kepler flight data demonstrate the effectiveness of our approach. Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA’s Science Mission Directorate.Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA’s Science Mission Directorate.

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.

Explaining sex differences in lifespan in terms of optimal energy allocation in the baboon.

PubMed

King, Annette M; Kirkwood, Thomas B L; Shanley, Daryl P

2017-10-01

We provide a quantitative test of the hypothesis that sex role specialization may account for sex differences in lifespan in baboons if such specialization causes the dependency of fitness upon longevity, and consequently the optimal resolution to an energetic trade-off between somatic maintenance and other physiological functions, to differ between males and females. We present a model in which females provide all offspring care and males compete for access to reproductive females and in which the partitioning of available energy between the competing fitness-enhancing functions of growth, maintenance, and reproduction is modeled as a dynamic behavioral game, with the optimal decision for each individual depending upon his/her state and the behavior of other members of the population. Our model replicates the sexual dimorphism in body size and sex differences in longevity and reproductive scheduling seen in natural populations of baboons. We show that this outcome is generally robust to perturbations in model parameters, an important finding given that the same behavior is seen across multiple populations and species in the wild. This supports the idea that sex differences in longevity result from differences in the value of somatic maintenance relative to other fitness-enhancing functions in keeping with the disposable soma theory. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Parametric regression model for survival data: Weibull regression model as an example

PubMed Central

2016-01-01

Weibull regression model is one of the most popular forms of parametric regression model that it provides estimate of baseline hazard function, as well as coefficients for covariates. Because of technical difficulties, Weibull regression model is seldom used in medical literature as compared to the semi-parametric proportional hazard model. To make clinical investigators familiar with Weibull regression model, this article introduces some basic knowledge on Weibull regression model and then illustrates how to fit the model with R software. The SurvRegCensCov package is useful in converting estimated coefficients to clinical relevant statistics such as hazard ratio (HR) and event time ratio (ETR). Model adequacy can be assessed by inspecting Kaplan-Meier curves stratified by categorical variable. The eha package provides an alternative method to model Weibull regression model. The check.dist() function helps to assess goodness-of-fit of the model. Variable selection is based on the importance of a covariate, which can be tested using anova() function. Alternatively, backward elimination starting from a full model is an efficient way for model development. Visualization of Weibull regression model after model development is interesting that it provides another way to report your findings. PMID:28149846

Childhood cardiorespiratory fitness, muscular fitness and adult measures of glucose homeostasis.

PubMed

Fraser, Brooklyn J; Blizzard, Leigh; Schmidt, Michael D; Juonala, Markus; Dwyer, Terence; Venn, Alison J; Magnussen, Costan G

2018-02-14

To assess whether childhood cardiorespiratory fitness (CRF) and muscular fitness phenotypes (strength, power, endurance) predict adult glucose homeostasis measures. Prospective longitudinal study. Study examining participants who had physical fitness measured in childhood (aged 7-15 years) and who attended follow-up clinics approximately 20 years later and provided a fasting blood sample which was tested for glucose and insulin. Physical fitness measurements included muscular strength (right and left grip, shoulder flexion, shoulder and leg extension), power (standing long jump distance) and endurance (number of push-ups in 30s), and CRF (1.6km run duration). In adulthood, fasting glucose and insulin levels were used to derive glucose homeostasis measures of insulin resistance (HOMA2-IR) and beta cell function (HOMA2-β). A standard deviation increase in childhood CRF or muscular strength (males) was associated with fasting glucose (CRF: β=-0.06mmol/L), fasting insulin (CRF: β=-0.73mU/L; strength: β=-0.40mU/L), HOMA2-IR (CRF: β=-0.06; strength: β=-0.05) and HOMA2-β (CRF: β=-3.06%; strength: β=-2.62%) in adulthood, independent of the alternative fitness phenotype (all p<0.01). Adjustment for childhood waist circumference reduced the effect by 17-35% for CRF and 0-15% for muscular strength (males) and statistical significance remained for all associations expect between CRF, fasting glucose and HOMA2-β (p>0.06). CRF and muscular fitness in childhood were inversely associated with measures of fasting insulin, insulin resistance and beta cell function in adulthood. Childhood CRF and muscular fitness could both be potential independent targets for strategies to help reduce the development of adverse glucose homeostasis. Copyright © 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Protofit: A program for determining surface protonation constants from titration data

NASA Astrophysics Data System (ADS)

Turner, Benjamin F.; Fein, Jeremy B.

2006-11-01

Determining the surface protonation behavior of natural adsorbents is essential to understand how they interact with their environments. ProtoFit is a tool for analysis of acid-base titration data and optimization of surface protonation models. The program offers a number of useful features including: (1) enables visualization of adsorbent buffering behavior; (2) uses an optimization approach independent of starting titration conditions or initial surface charge; (3) does not require an initial surface charge to be defined or to be treated as an optimizable parameter; (4) includes an error analysis intrinsically as part of the computational methods; and (5) generates simulated titration curves for comparison with observation. ProtoFit will typically be run through ProtoFit-GUI, a graphical user interface providing user-friendly control of model optimization, simulation, and data visualization. ProtoFit calculates an adsorbent proton buffering value as a function of pH from raw titration data (including pH and volume of acid or base added). The data is reduced to a form where the protons required to change the pH of the solution are subtracted out, leaving protons exchanged between solution and surface per unit mass of adsorbent as a function of pH. The buffering intensity function Qads* is calculated as the instantaneous slope of this reduced titration curve. Parameters for a surface complexation model are obtained by minimizing the sum of squares between the modeled (i.e. simulated) buffering intensity curve and the experimental data. The variance in the slope estimate, intrinsically produced as part of the Qads* calculation, can be used to weight the sum of squares calculation between the measured buffering intensity and a simulated curve. Effects of analytical error on data visualization and model optimization are discussed. Examples are provided of using ProtoFit for data visualization, model optimization, and model evaluation.

Focal ratio degradation: a new perspective

NASA Astrophysics Data System (ADS)

Haynes, Dionne M.; Withford, Michael J.; Dawes, Judith M.; Haynes, Roger; Bland-Hawthorn, Joss

2008-07-01

We have developed an alternative FRD empirical model for the parallel laser beam technique which can accommodate contributions from both scattering and modal diffusion. It is consistent with scattering inducing a Lorentzian contribution and modal diffusion inducing a Gaussian contribution. The convolution of these two functions produces a Voigt function which is shown to better simulate the observed behavior of the FRD distribution and provides a greatly improved fit over the standard Gaussian fitting approach. The Voigt model can also be used to quantify the amount of energy displaced by FRD, therefore allowing astronomical instrument scientists to identify, quantify and potentially minimize the various sources of FRD, and optimise the fiber and instrument performance.

Method for Making Measurements of the Post-Combustion Residence Time in a Gas Turbine Engine

NASA Technical Reports Server (NTRS)

Miles, Jeffrey H (Inventor)

2015-01-01

A system and method of measuring a residence time in a gas-turbine engine is provided, whereby the method includes placing pressure sensors at a combustor entrance and at a turbine exit of the gas-turbine engine and measuring a combustor pressure at the combustor entrance and a turbine exit pressure at the turbine exit. The method further includes computing cross-spectrum functions between a combustor pressure sensor signal from the measured combustor pressure and a turbine exit pressure sensor signal from the measured turbine exit pressure, applying a linear curve fit to the cross-spectrum functions, and computing a post-combustion residence time from the linear curve fit.

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…

Trial-dependent psychometric functions accounting for perceptual learning in 2-AFC discrimination tasks.

PubMed

Kattner, Florian; Cochrane, Aaron; Green, C Shawn

2017-09-01

The majority of theoretical models of learning consider learning to be a continuous function of experience. However, most perceptual learning studies use thresholds estimated by fitting psychometric functions to independent blocks, sometimes then fitting a parametric function to these block-wise estimated thresholds. Critically, such approaches tend to violate the basic principle that learning is continuous through time (e.g., by aggregating trials into large "blocks" for analysis that each assume stationarity, then fitting learning functions to these aggregated blocks). To address this discrepancy between base theory and analysis practice, here we instead propose fitting a parametric function to thresholds from each individual trial. In particular, we implemented a dynamic psychometric function whose parameters were allowed to change continuously with each trial, thus parameterizing nonstationarity. We fit the resulting continuous time parametric model to data from two different perceptual learning tasks. In nearly every case, the quality of the fits derived from the continuous time parametric model outperformed the fits derived from a nonparametric approach wherein separate psychometric functions were fit to blocks of trials. Because such a continuous trial-dependent model of perceptual learning also offers a number of additional advantages (e.g., the ability to extrapolate beyond the observed data; the ability to estimate performance on individual critical trials), we suggest that this technique would be a useful addition to each psychophysicist's analysis toolkit.

The Double Star Orbit Initial Value Problem

NASA Astrophysics Data System (ADS)

Hensley, Hagan

2018-04-01

Many precise algorithms exist to find a best-fit orbital solution for a double star system given a good enough initial value. Desmos is an online graphing calculator tool with extensive capabilities to support animations and defining functions. It can provide a useful visual means of analyzing double star data to arrive at a best guess approximation of the orbital solution. This is a necessary requirement before using a gradient-descent algorithm to find the best-fit orbital solution for a binary system.

The relation of education and cognitive activity to mini-mental state in old age: the role of functional fitness status.

PubMed

Ihle, Andreas; Gouveia, Élvio R; Gouveia, Bruna R; Freitas, Duarte L; Jurema, Jefferson; Ornelas, Rui T; Antunes, António M; Muniz, Bárbara R; Kliegel, Matthias

2018-06-01

It remains unclear so far whether the role of cognitive reserve for cognitive functioning in old age may differ between individuals with low, compared to those with high functional fitness status. Therefore, the present study set out to investigate the relation of education and cognitive leisure activity as key markers of cognitive reserve to mini-mental state in old age (as an indicator of the extent of cognitive impairment) and its interplay with functional fitness status in a large sample of older adults. We assessed MMSE in 701 older adults ( M  = 70.4 years, SD = 6.9, range: 60-91). We measured functional fitness status using the Senior Fitness Test battery and interviewed individuals on their education and cognitive leisure activity. Results showed that better functional fitness status, longer education, and greater engagement in cognitive leisure activity were significantly related to higher MMSE scores. Moderation analyses showed that the relations of education and cognitive leisure activity to MMSE scores were significantly larger in individuals with low, compared to those with high functional fitness status. In conclusion, cognitive functioning in old age may more strongly depend on cognitive reserve accumulated during the life course in older adults with low, compared to those with high functional fitness status. These findings may be explained by cross-domain compensation effects in vulnerable individuals and may (at least partly) account for the large variability in cognitive reserve-cognition relations debated in the literature.

Virtual C Machine and Integrated Development Environment for ATMS Controllers.

DOT National Transportation Integrated Search

2000-04-01

The overall objective of this project is to develop a prototype virtual machine that fits on current Advanced Traffic Management Systems (ATMS) controllers and provides functionality for complex traffic operations.;Prepared in cooperation with Utah S...

Novel Histogram Based Unsupervised Classification Technique to Determine Natural Classes From Biophysically Relevant Fit Parameters to Hyperspectral Data

DOE PAGES

McCann, Cooper; Repasky, Kevin S.; Morin, Mikindra; ...

2017-05-23

Hyperspectral image analysis has benefited from an array of methods that take advantage of the increased spectral depth compared to multispectral sensors; however, the focus of these developments has been on supervised classification methods. Lack of a priori knowledge regarding land cover characteristics can make unsupervised classification methods preferable under certain circumstances. An unsupervised classification technique is presented in this paper that utilizes physically relevant basis functions to model the reflectance spectra. These fit parameters used to generate the basis functions allow clustering based on spectral characteristics rather than spectral channels and provide both noise and data reduction. Histogram splittingmore » of the fit parameters is then used as a means of producing an unsupervised classification. Unlike current unsupervised classification techniques that rely primarily on Euclidian distance measures to determine similarity, the unsupervised classification technique uses the natural splitting of the fit parameters associated with the basis functions creating clusters that are similar in terms of physical parameters. The data set used in this work utilizes the publicly available data collected at Indian Pines, Indiana. This data set provides reference data allowing for comparisons of the efficacy of different unsupervised data analysis. The unsupervised histogram splitting technique presented in this paper is shown to be better than the standard unsupervised ISODATA clustering technique with an overall accuracy of 34.3/19.0% before merging and 40.9/39.2% after merging. Finally, this improvement is also seen as an improvement of kappa before/after merging of 24.8/30.5 for the histogram splitting technique compared to 15.8/28.5 for ISODATA.« less

Novel Histogram Based Unsupervised Classification Technique to Determine Natural Classes From Biophysically Relevant Fit Parameters to Hyperspectral Data

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

McCann, Cooper; Repasky, Kevin S.; Morin, Mikindra

Hyperspectral image analysis has benefited from an array of methods that take advantage of the increased spectral depth compared to multispectral sensors; however, the focus of these developments has been on supervised classification methods. Lack of a priori knowledge regarding land cover characteristics can make unsupervised classification methods preferable under certain circumstances. An unsupervised classification technique is presented in this paper that utilizes physically relevant basis functions to model the reflectance spectra. These fit parameters used to generate the basis functions allow clustering based on spectral characteristics rather than spectral channels and provide both noise and data reduction. Histogram splittingmore » of the fit parameters is then used as a means of producing an unsupervised classification. Unlike current unsupervised classification techniques that rely primarily on Euclidian distance measures to determine similarity, the unsupervised classification technique uses the natural splitting of the fit parameters associated with the basis functions creating clusters that are similar in terms of physical parameters. The data set used in this work utilizes the publicly available data collected at Indian Pines, Indiana. This data set provides reference data allowing for comparisons of the efficacy of different unsupervised data analysis. The unsupervised histogram splitting technique presented in this paper is shown to be better than the standard unsupervised ISODATA clustering technique with an overall accuracy of 34.3/19.0% before merging and 40.9/39.2% after merging. Finally, this improvement is also seen as an improvement of kappa before/after merging of 24.8/30.5 for the histogram splitting technique compared to 15.8/28.5 for ISODATA.« less

Development of a Self-Report Physical Function Instrument for Disability Assessment: Item Pool Construction and Factor Analysis

PubMed Central

McDonough, Christine M.; Jette, Alan M.; Ni, Pengsheng; Bogusz, Kara; Marfeo, Elizabeth E; Brandt, Diane E; Chan, Leighton; Meterko, Mark; Haley, Stephen M.; Rasch, Elizabeth K.

2014-01-01

Objectives To build a comprehensive item pool representing work-relevant physical functioning and to test the factor structure of the item pool. These developmental steps represent initial outcomes of a broader project to develop instruments for the assessment of function within the context of Social Security Administration (SSA) disability programs. Design Comprehensive literature review; gap analysis; item generation with expert panel input; stakeholder interviews; cognitive interviews; cross-sectional survey administration; and exploratory and confirmatory factor analyses to assess item pool structure. Setting In-person and semi-structured interviews; internet and telephone surveys. Participants A sample of 1,017 SSA claimants, and a normative sample of 999 adults from the US general population. Interventions Not Applicable. Main Outcome Measure Model fit statistics Results The final item pool consisted of 139 items. Within the claimant sample 58.7% were white; 31.8% were black; 46.6% were female; and the mean age was 49.7 years. Initial factor analyses revealed a 4-factor solution which included more items and allowed separate characterization of: 1) Changing and Maintaining Body Position, 2) Whole Body Mobility, 3) Upper Body Function and 4) Upper Extremity Fine Motor. The final 4-factor model included 91 items. Confirmatory factor analyses for the 4-factor models for the claimant and the normative samples demonstrated very good fit. Fit statistics for claimant and normative samples respectively were: Comparative Fit Index = 0.93 and 0.98; Tucker-Lewis Index = 0.92 and 0.98; Root Mean Square Error Approximation = 0.05 and 0.04. Conclusions The factor structure of the Physical Function item pool closely resembled the hypothesized content model. The four scales relevant to work activities offer promise for providing reliable information about claimant physical functioning relevant to work disability. PMID:23542402

Development of a self-report physical function instrument for disability assessment: item pool construction and factor analysis.

PubMed

McDonough, Christine M; Jette, Alan M; Ni, Pengsheng; Bogusz, Kara; Marfeo, Elizabeth E; Brandt, Diane E; Chan, Leighton; Meterko, Mark; Haley, Stephen M; Rasch, Elizabeth K

2013-09-01

To build a comprehensive item pool representing work-relevant physical functioning and to test the factor structure of the item pool. These developmental steps represent initial outcomes of a broader project to develop instruments for the assessment of function within the context of Social Security Administration (SSA) disability programs. Comprehensive literature review; gap analysis; item generation with expert panel input; stakeholder interviews; cognitive interviews; cross-sectional survey administration; and exploratory and confirmatory factor analyses to assess item pool structure. In-person and semistructured interviews and Internet and telephone surveys. Sample of SSA claimants (n=1017) and a normative sample of adults from the U.S. general population (n=999). Not applicable. Model fit statistics. The final item pool consisted of 139 items. Within the claimant sample, 58.7% were white; 31.8% were black; 46.6% were women; and the mean age was 49.7 years. Initial factor analyses revealed a 4-factor solution, which included more items and allowed separate characterization of: (1) changing and maintaining body position, (2) whole body mobility, (3) upper body function, and (4) upper extremity fine motor. The final 4-factor model included 91 items. Confirmatory factor analyses for the 4-factor models for the claimant and the normative samples demonstrated very good fit. Fit statistics for claimant and normative samples, respectively, were: Comparative Fit Index=.93 and .98; Tucker-Lewis Index=.92 and .98; and root mean square error approximation=.05 and .04. The factor structure of the physical function item pool closely resembled the hypothesized content model. The 4 scales relevant to work activities offer promise for providing reliable information about claimant physical functioning relevant to work disability. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Hybrid genetic algorithm with an adaptive penalty function for fitting multimodal experimental data: application to exchange-coupled non-Kramers binuclear iron active sites.

PubMed

Beaser, Eric; Schwartz, Jennifer K; Bell, Caleb B; Solomon, Edward I

2011-09-26

A Genetic Algorithm (GA) is a stochastic optimization technique based on the mechanisms of biological evolution. These algorithms have been successfully applied in many fields to solve a variety of complex nonlinear problems. While they have been used with some success in chemical problems such as fitting spectroscopic and kinetic data, many have avoided their use due to the unconstrained nature of the fitting process. In engineering, this problem is now being addressed through incorporation of adaptive penalty functions, but their transfer to other fields has been slow. This study updates the Nanakorrn Adaptive Penalty function theory, expanding its validity beyond maximization problems to minimization as well. The expanded theory, using a hybrid genetic algorithm with an adaptive penalty function, was applied to analyze variable temperature variable field magnetic circular dichroism (VTVH MCD) spectroscopic data collected on exchange coupled Fe(II)Fe(II) enzyme active sites. The data obtained are described by a complex nonlinear multimodal solution space with at least 6 to 13 interdependent variables and are costly to search efficiently. The use of the hybrid GA is shown to improve the probability of detecting the global optimum. It also provides large gains in computational and user efficiency. This method allows a full search of a multimodal solution space, greatly improving the quality and confidence in the final solution obtained, and can be applied to other complex systems such as fitting of other spectroscopic or kinetics data.

Deconvolution of Stark broadened spectra for multi-point density measurements in a flow Z-pinch

DOE PAGES

Vogman, G. V.; Shumlak, U.

2011-10-13

Stark broadened emission spectra, once separated from other broadening effects, provide a convenient non-perturbing means of making plasma density measurements. A deconvolution technique has been developed to measure plasma densities in the ZaP flow Z-pinch experiment. The ZaP experiment uses sheared flow to mitigate MHD instabilities. The pinches exhibit Stark broadened emission spectra, which are captured at 20 locations using a multi-chord spectroscopic system. Spectra that are time- and chord-integrated are well approximated by a Voigt function. The proposed method simultaneously resolves plasma electron density and ion temperature by deconvolving the spectral Voigt profile into constituent functions: a Gaussian functionmore » associated with instrument effects and Doppler broadening by temperature; and a Lorentzian function associated with Stark broadening by electron density. The method uses analytic Fourier transforms of the constituent functions to fit the Voigt profile in the Fourier domain. The method is discussed and compared to a basic least-squares fit. The Fourier transform fitting routine requires fewer fitting parameters and shows promise in being less susceptible to instrumental noise and to contamination from neighboring spectral lines. The method is evaluated and tested using simulated lines and is applied to experimental data for the 229.69 nm C III line from multiple chords to determine plasma density and temperature across the diameter of the pinch. As a result, these measurements are used to gain a better understanding of Z-pinch equilibria.« less

Deconvolution of Stark broadened spectra for multi-point density measurements in a flow Z-pinch

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

Vogman, G. V.; Shumlak, U.

2011-10-15

Stark broadened emission spectra, once separated from other broadening effects, provide a convenient non-perturbing means of making plasma density measurements. A deconvolution technique has been developed to measure plasma densities in the ZaP flow Z-pinch experiment. The ZaP experiment uses sheared flow to mitigate MHD instabilities. The pinches exhibit Stark broadened emission spectra, which are captured at 20 locations using a multi-chord spectroscopic system. Spectra that are time- and chord-integrated are well approximated by a Voigt function. The proposed method simultaneously resolves plasma electron density and ion temperature by deconvolving the spectral Voigt profile into constituent functions: a Gaussian functionmore » associated with instrument effects and Doppler broadening by temperature; and a Lorentzian function associated with Stark broadening by electron density. The method uses analytic Fourier transforms of the constituent functions to fit the Voigt profile in the Fourier domain. The method is discussed and compared to a basic least-squares fit. The Fourier transform fitting routine requires fewer fitting parameters and shows promise in being less susceptible to instrumental noise and to contamination from neighboring spectral lines. The method is evaluated and tested using simulated lines and is applied to experimental data for the 229.69 nm C III line from multiple chords to determine plasma density and temperature across the diameter of the pinch. These measurements are used to gain a better understanding of Z-pinch equilibria.« less

Impact of physical fitness on salivary stress markers in sedentary to low-active young to middle-aged men.

PubMed

Strahler, Jana; Fuchs, Reinhard; Nater, Urs M; Klaperski, Sandra

2016-06-01

Salivary cortisol (sCort) and alpha-amylase (sAA) are popular measurement tools for investigating hypothalamic-pituitary-adrenal and autonomic functioning, respectively. Despite their widespread use, only little is known about whether lifestyle factors such as regular exercise and physical fitness impact these two salivary stress markers. The lack of an objectively assessed fitness status is a major drawback of nearly all previous studies in this area. Our main objective was therefore to examine the impact of fitness status on sCort and sAA responses to a validated stressor. Sedentary to low-active men (N=115, 45.7±10.1 years, 26.7±3.4kg/m(2)) were exposed to the Trier Social Stress Test for Groups and provided saliva samples before and repeatedly after the stressor. An ergometer lactate exercise test provided information on physical fitness, that is, power achieved at the individual anaerobic threshold relative to body weight. From age-specific percentiles, a 2- (n=65 low fitness, n=50 high fitness) and a 3-group (n=37 low fitness, n=49 moderate fitness, n=29 high fitness) solution were calculated to elucidate the impact of different fitness levels. Prior to stress testing, sCort and sAA levels were similar in all groups. While both markers increased significantly due to stress exposure, fitness effects appeared rather small. When applying the 3-group solution, we observed attenuated sCort slopes in high- and moderate-fit men. Although sAA response slopes were pronounced in high-fit men, they failed to reach statistical significance. Mean stress reactivity (area under the curve with respect to ground, baseline, and response maximum) did not differ between groups and no association with fitness level was found. Our findings suggest only a weak effect of objectively assessed physical fitness on biological stress responses with attenuated hypothalamic-pituitary-adrenal but (non-significantly) higher autonomic responses in fitter men. Physical fitness is a factor that should not be neglected in future studies employing salivary stress markers, especially in studies interested in acute stress responses. Copyright © 2016 Elsevier Ltd. All rights reserved.

Deadline rush: a time management phenomenon and its mathematical description.

PubMed

König, Cornelius J; Kleinmann, Martin

2005-01-01

A typical time management phenomenon is the rush before a deadline. Behavioral decision making research can be used to predict how behavior changes before a deadline. People are likely not to work on a project with a deadline in the far future because they generally discount future outcomes. Only when the deadline is close are people likely to work. On the basis of recent intertemporal choice experiments, the authors argue that a hyperbolic function should provide a more accurate description of the deadline rush than an exponential function predicted by an economic model of discounted utility. To show this, the fit of the hyperbolic and the exponential function were compared with data sets that describe when students study for exams. As predicted, the hyperbolic function fit the data significantly better than the exponential function. The implication for time management decisions is that they are most likely to be inconsistent over time (i.e., people make a plan how to use their time but do not follow it).

Comment on the asymptotics of a distribution-free goodness of fit test statistic.

PubMed

Browne, Michael W; Shapiro, Alexander

2015-03-01

In a recent article Jennrich and Satorra (Psychometrika 78: 545-552, 2013) showed that a proof by Browne (British Journal of Mathematical and Statistical Psychology 37: 62-83, 1984) of the asymptotic distribution of a goodness of fit test statistic is incomplete because it fails to prove that the orthogonal component function employed is continuous. Jennrich and Satorra (Psychometrika 78: 545-552, 2013) showed how Browne's proof can be completed satisfactorily but this required the development of an extensive and mathematically sophisticated framework for continuous orthogonal component functions. This short note provides a simple proof of the asymptotic distribution of Browne's (British Journal of Mathematical and Statistical Psychology 37: 62-83, 1984) test statistic by using an equivalent form of the statistic that does not involve orthogonal component functions and consequently avoids all complicating issues associated with them.

Physical fitness is predictive for a decline in daily functioning in older adults with intellectual disabilities: results of the HA-ID study.

PubMed

Oppewal, Alyt; Hilgenkamp, Thessa I M; van Wijck, Ruud; Schoufour, Josje D; Evenhuis, Heleen M

2014-10-01

A high incidence of limitations in daily functioning is seen in older adults with intellectual disabilities (ID), along with poor physical fitness levels. The aim of this study was to assess the predictive value of physical fitness for daily functioning after 3 years, in 602 older adults with borderline to profound ID (≥ 50 years). At baseline, physical fitness levels and daily functioning (operationalized as basic activities of daily living [ADL] and mobility) were assessed. After 3 years, the measurements of daily functioning were repeated. At follow-up, 12.6% of the participants were completely independent in ADL and 48.5% had no mobility limitations. More than half of the participants (54.8%) declined in their ability to perform ADL and 37.5% declined in their mobility. Manual dexterity, visual reaction time, balance, comfortable and fast gait speed, muscular endurance, and cardiorespiratory fitness were significant predictors for a decline in ADL. For a decline in mobility, manual dexterity, balance, comfortable and fast walking speed, grip strength, muscular endurance, and cardiorespiratory fitness were all significant predictors. This proves the predictive validity of these physical fitness tests for daily functioning and stresses the importance of using physical fitness tests and implementing physical fitness enhancing programs in the care for older adults with ID. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Generation, Radiation and Prediction of Supersonic Jet Noise. Volume 1

DTIC Science & Technology

1978-10-01

standard, Gaussian correlation function model can yield a good noise spectrum prediction (at 900), but the corresponding axial source distributions do not...forms for the turbulence cross-correlation function. Good agreement was obtained between measured and calculated far- field noise spectra. However, the...complementary error function profile (3.63) was found to provide a good fit to the axial velocity distribution tor a wide range of Mach numbers in the Initial

A non-linear regression analysis program for describing electrophysiological data with multiple functions using Microsoft Excel.

PubMed

Brown, Angus M

2006-04-01

The objective of this present study was to demonstrate a method for fitting complex electrophysiological data with multiple functions using the SOLVER add-in of the ubiquitous spreadsheet Microsoft Excel. SOLVER minimizes the difference between the sum of the squares of the data to be fit and the function(s) describing the data using an iterative generalized reduced gradient method. While it is a straightforward procedure to fit data with linear functions, and we have previously demonstrated a method of non-linear regression analysis of experimental data based upon a single function, it is more complex to fit data with multiple functions, usually requiring specialized expensive computer software. In this paper we describe an easily understood program for fitting experimentally acquired data, in this case the stimulus-evoked compound action potential from the mouse optic nerve, with multiple Gaussian functions. The program is flexible and can be applied to describe data with a wide variety of user-input functions.

Estimating errors in least-squares fitting

NASA Technical Reports Server (NTRS)

Richter, P. H.

1995-01-01

While least-squares fitting procedures are commonly used in data analysis and are extensively discussed in the literature devoted to this subject, the proper assessment of errors resulting from such fits has received relatively little attention. The present work considers statistical errors in the fitted parameters, as well as in the values of the fitted function itself, resulting from random errors in the data. Expressions are derived for the standard error of the fit, as a function of the independent variable, for the general nonlinear and linear fitting problems. Additionally, closed-form expressions are derived for some examples commonly encountered in the scientific and engineering fields, namely ordinary polynomial and Gaussian fitting functions. These results have direct application to the assessment of the antenna gain and system temperature characteristics, in addition to a broad range of problems in data analysis. The effects of the nature of the data and the choice of fitting function on the ability to accurately model the system under study are discussed, and some general rules are deduced to assist workers intent on maximizing the amount of information obtained form a given set of measurements.

Directed evolution of a model primordial enzyme provides insights into the development of the genetic code.

PubMed

Müller, Manuel M; Allison, Jane R; Hongdilokkul, Narupat; Gaillon, Laurent; Kast, Peter; van Gunsteren, Wilfred F; Marlière, Philippe; Hilvert, Donald

2013-01-01

The contemporary proteinogenic repertoire contains 20 amino acids with diverse functional groups and side chain geometries. Primordial proteins, in contrast, were presumably constructed from a subset of these building blocks. Subsequent expansion of the proteinogenic alphabet would have enhanced their capabilities, fostering the metabolic prowess and organismal fitness of early living systems. While the addition of amino acids bearing innovative functional groups directly enhances the chemical repertoire of proteomes, the inclusion of chemically redundant monomers is difficult to rationalize. Here, we studied how a simplified chorismate mutase evolves upon expanding its amino acid alphabet from nine to potentially 20 letters. Continuous evolution provided an enhanced enzyme variant that has only two point mutations, both of which extend the alphabet and jointly improve protein stability by >4 kcal/mol and catalytic activity tenfold. The same, seemingly innocuous substitutions (Ile→Thr, Leu→Val) occurred in several independent evolutionary trajectories. The increase in fitness they confer indicates that building blocks with very similar side chain structures are highly beneficial for fine-tuning protein structure and function.

Elastic Band Exercises Improved Activities of Daily Living and Functional Fitness of Wheelchair-bound Older Adults with Cognitive Impairment: A Cluster Randomized Controlled Trial.

PubMed

Chen, Meng-Chun; Chen, Kuei-Min; Chang, Chu-Lin; Chang, Ya-Hui; Cheng, Yin-Yin; Huang, Hsin-Ting

2016-11-01

The purpose of this study was to test the effects of a 6-month Wheelchair-bound Senior Elastic Band (WSEB) exercise program on the activities of daily living (ADL) and functional fitness of wheelchair-bound older adults with cognitive impairment. Cluster randomized controlled trial was used. A convenience sample of 138 wheelchair-bound older adults with cognitive impairment were recruited from 8 nursing homes in southern Taiwan and were randomly assigned based on the nursing homes they lived to the experimental (4 nursing homes; n = 73) or the control group (4 nursing homes; n = 65). The experimental group performed WSEB exercises 3 times per week and 40 minutes per session for 6 months. The ADL and functional fitness (cardiopulmonary function, body flexibility, range of joint motion, and muscle strength and endurance) were examined at baseline, 3 months, and the end of 6-month study. The ADL and functional fitness indicators of participants in the experimental group showed significant improvements compared to the control group (all P < 0.05). The WSEB exercises have positive benefits for the ADL and functional fitness of wheelchair-bound older adults with cognitive impairment. It is suggested that WSEB exercises be included as a routine activity in nursing homes. Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCMECME OBJECTIVES:: Upon completion of this article the reader should be able to: (1) Understand the risk factors for functional decline in older adults with dementia; (2) Articulate the benefits of structured activities and exercises in the older adult with dementia; and (3) Incorporate elastic band exercises into the treatment plan of wheelchair bound older adults with dementia. AdvancedACCREDITATION:: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The Association of Academic Physiatrists designates this activity for a maximum of 1.5 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Curve fitting air sample filter decay curves to estimate transuranic content.

PubMed

Hayes, Robert B; Chiou, Hung Cheng

2004-01-01

By testing industry standard techniques for radon progeny evaluation on air sample filters, a new technique is developed to evaluate transuranic activity on air filters by curve fitting the decay curves. The industry method modified here is simply the use of filter activity measurements at different times to estimate the air concentrations of radon progeny. The primary modification was to not look for specific radon progeny values but rather transuranic activity. By using a method that will provide reasonably conservative estimates of the transuranic activity present on a filter, some credit for the decay curve shape can then be taken. By carrying out rigorous statistical analysis of the curve fits to over 65 samples having no transuranic activity taken over a 10-mo period, an optimization of the fitting function and quality tests for this purpose was attained.

Random regression models using Legendre polynomials or linear splines for test-day milk yield of dairy Gyr (Bos indicus) cattle.

PubMed

Pereira, R J; Bignardi, A B; El Faro, L; Verneque, R S; Vercesi Filho, A E; Albuquerque, L G

2013-01-01

Studies investigating the use of random regression models for genetic evaluation of milk production in Zebu cattle are scarce. In this study, 59,744 test-day milk yield records from 7,810 first lactations of purebred dairy Gyr (Bos indicus) and crossbred (dairy Gyr × Holstein) cows were used to compare random regression models in which additive genetic and permanent environmental effects were modeled using orthogonal Legendre polynomials or linear spline functions. Residual variances were modeled considering 1, 5, or 10 classes of days in milk. Five classes fitted the changes in residual variances over the lactation adequately and were used for model comparison. The model that fitted linear spline functions with 6 knots provided the lowest sum of residual variances across lactation. On the other hand, according to the deviance information criterion (DIC) and bayesian information criterion (BIC), a model using third-order and fourth-order Legendre polynomials for additive genetic and permanent environmental effects, respectively, provided the best fit. However, the high rank correlation (0.998) between this model and that applying third-order Legendre polynomials for additive genetic and permanent environmental effects, indicates that, in practice, the same bulls would be selected by both models. The last model, which is less parameterized, is a parsimonious option for fitting dairy Gyr breed test-day milk yield records. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Exercise and multiple sclerosis.

PubMed

White, Lesley J; Dressendorfer, Rudolph H

2004-01-01

The pathophysiology of multiple sclerosis (MS) is characterised by fatigue, motor weakness, spasticity, poor balance, heat sensitivity and mental depression. Also, MS symptoms may lead to physical inactivity associated with the development of secondary diseases. Persons with MS are thus challenged by their disability when attempting to pursue an active lifestyle compatible with health-related fitness. Although exercise prescription is gaining favour as a therapeutic strategy to minimise the loss of functional capacity in chronic diseases, it remains under-utilised as an intervention strategy in the MS population. However, a growing number of studies indicate that exercise in patients with mild-to-moderate MS provides similar fitness and psychological benefits as it does in healthy controls. We reviewed numerous studies describing the responses of selected MS patients to acute and chronic exercise compared with healthy controls. All training studies reported positive outcomes that outweighed potential adverse effects of the exercise intervention. Based on our review, this article highlights the role of exercise prescription in the multidisciplinary approach to MS disease management for improving and maintaining functional capacity. Despite the often unpredictable clinical course of MS, exercise programmes designed to increase cardiorespiratory fitness, muscle strength and mobility provide benefits that enhance lifestyle activity and quality of life while reducing risk of secondary disorders. Recommendations for the evaluation of cardiorespiratory fitness, muscle performance and flexibility are presented as well as basic guidelines for individualised exercise testing and training in MS. Special considerations for exercise, including medical management concerns, programme modifications and supervision, in the MS population are discussed.

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.

Joint estimation of preferential attachment and node fitness in growing complex networks

NASA Astrophysics Data System (ADS)

Pham, Thong; Sheridan, Paul; Shimodaira, Hidetoshi

2016-09-01

Complex network growth across diverse fields of science is hypothesized to be driven in the main by a combination of preferential attachment and node fitness processes. For measuring the respective influences of these processes, previous approaches make strong and untested assumptions on the functional forms of either the preferential attachment function or fitness function or both. We introduce a Bayesian statistical method called PAFit to estimate preferential attachment and node fitness without imposing such functional constraints that works by maximizing a log-likelihood function with suitably added regularization terms. We use PAFit to investigate the interplay between preferential attachment and node fitness processes in a Facebook wall-post network. While we uncover evidence for both preferential attachment and node fitness, thus validating the hypothesis that these processes together drive complex network evolution, we also find that node fitness plays the bigger role in determining the degree of a node. This is the first validation of its kind on real-world network data. But surprisingly the rate of preferential attachment is found to deviate from the conventional log-linear form when node fitness is taken into account. The proposed method is implemented in the R package PAFit.

Joint estimation of preferential attachment and node fitness in growing complex networks

PubMed Central

Pham, Thong; Sheridan, Paul; Shimodaira, Hidetoshi

2016-01-01

Complex network growth across diverse fields of science is hypothesized to be driven in the main by a combination of preferential attachment and node fitness processes. For measuring the respective influences of these processes, previous approaches make strong and untested assumptions on the functional forms of either the preferential attachment function or fitness function or both. We introduce a Bayesian statistical method called PAFit to estimate preferential attachment and node fitness without imposing such functional constraints that works by maximizing a log-likelihood function with suitably added regularization terms. We use PAFit to investigate the interplay between preferential attachment and node fitness processes in a Facebook wall-post network. While we uncover evidence for both preferential attachment and node fitness, thus validating the hypothesis that these processes together drive complex network evolution, we also find that node fitness plays the bigger role in determining the degree of a node. This is the first validation of its kind on real-world network data. But surprisingly the rate of preferential attachment is found to deviate from the conventional log-linear form when node fitness is taken into account. The proposed method is implemented in the R package PAFit. PMID:27601314

Unified halo-independent formalism from convex hulls for direct dark matter searches

NASA Astrophysics Data System (ADS)

Gelmini, Graciela B.; Huh, Ji-Haeng; Witte, Samuel J.

2017-12-01

Using the Fenchel-Eggleston theorem for convex hulls (an extension of the Caratheodory theorem), we prove that any likelihood can be maximized by either a dark matter 1- speed distribution F(v) in Earth's frame or 2- Galactic velocity distribution fgal(vec u), consisting of a sum of delta functions. The former case applies only to time-averaged rate measurements and the maximum number of delta functions is (Script N‑1), where Script N is the total number of data entries. The second case applies to any harmonic expansion coefficient of the time-dependent rate and the maximum number of terms is Script N. Using time-averaged rates, the aforementioned form of F(v) results in a piecewise constant unmodulated halo function tilde eta0BF(vmin) (which is an integral of the speed distribution) with at most (Script N-1) downward steps. The authors had previously proven this result for likelihoods comprised of at least one extended likelihood, and found the best-fit halo function to be unique. This uniqueness, however, cannot be guaranteed in the more general analysis applied to arbitrary likelihoods. Thus we introduce a method for determining whether there exists a unique best-fit halo function, and provide a procedure for constructing either a pointwise confidence band, if the best-fit halo function is unique, or a degeneracy band, if it is not. Using measurements of modulation amplitudes, the aforementioned form of fgal(vec u), which is a sum of Galactic streams, yields a periodic time-dependent halo function tilde etaBF(vmin, t) which at any fixed time is a piecewise constant function of vmin with at most Script N downward steps. In this case, we explain how to construct pointwise confidence and degeneracy bands from the time-averaged halo function. Finally, we show that requiring an isotropic Galactic velocity distribution leads to a Galactic speed distribution F(u) that is once again a sum of delta functions, and produces a time-dependent tilde etaBF(vmin, t) function (and a time-averaged tilde eta0BF(vmin)) that is piecewise linear, differing significantly from best-fit halo functions obtained without the assumption of isotropy.

Consistency with synchrotron emission in the bright GRB 160625B observed by Fermi

NASA Astrophysics Data System (ADS)

Ravasio, M. E.; Oganesyan, G.; Ghirlanda, G.; Nava, L.; Ghisellini, G.; Pescalli, A.; Celotti, A.

2018-05-01

We present time-resolved spectral analysis of prompt emission from GRB 160625B, one of the brightest bursts ever detected by Fermi in its nine years of operations. Standard empirical functions fail to provide an acceptable fit to the GBM spectral data, which instead require the addition of a low-energy break to the fitting function. We introduce a new fitting function, called 2SBPL, consisting of three smoothly connected power laws. Fitting this model to the data, the goodness of the fits significantly improves and the spectral parameters are well constrained. We also test a spectral model that combines non-thermal and thermal (black body) components, but find that the 2SBPL model is systematically favoured. The spectral evolution shows that the spectral break is located around Ebreak 100 keV, while the usual νFν peak energy feature Epeak evolves in the 0.5-6 MeV energy range. The slopes below and above Ebreak are consistent with the values -0.67 and -1.5, respectively, expected from synchrotron emission produced by a relativistic electron population with a low-energy cut-off. If Ebreak is interpreted as the synchrotron cooling frequency, the implied magnetic field in the emitting region is 10 Gauss, i.e. orders of magnitudes smaller than the value expected for a dissipation region located at 1013-14 cm from the central engine. The low ratio between Epeak and Ebreak implies that the radiative cooling is incomplete, contrary to what is expected in strongly magnetized and compact emitting regions.

The structure of intelligence in children and adults with high functioning autism

PubMed Central

Goldstein, Gerald; Allen, Daniel N.; Minshew, Nancy J.; Williams, Diane L.; Volkmar, Fred; Klin, Ami; Schultz, Robert J.

2011-01-01

Confirmatory factor analyses of the traditional 11 subtests of the Wechsler child and adult intelligence scales were accomplished for 137 children and 118 adults with high functioning autism (HFA) and for comparable age groups from the standardization samples contained in the Wechsler manuals. The objective was determining whether HFA groups produced similar best fitting models to those found in the normative samples or formed a separate “social intelligence” factor. Four-factor models incorporating a “social intelligence” factor provided the best fit in both the autism and normative, but the subtest intercorrelations were generally lower in the autism samples. Findings were interpreted in terms of underconnectivity or reduced communication among brain regions in autism. PMID:18444708

IMAGE EXPLORER: Astronomical Image Analysis on an HTML5-based Web Application

NASA Astrophysics Data System (ADS)

Gopu, A.; Hayashi, S.; Young, M. D.

2014-05-01

Large datasets produced by recent astronomical imagers cause the traditional paradigm for basic visual analysis - typically downloading one's entire image dataset and using desktop clients like DS9, Aladin, etc. - to not scale, despite advances in desktop computing power and storage. This paper describes Image Explorer, a web framework that offers several of the basic visualization and analysis functionality commonly provided by tools like DS9, on any HTML5 capable web browser on various platforms. It uses a combination of the modern HTML5 canvas, JavaScript, and several layers of lossless PNG tiles producted from the FITS image data. Astronomers are able to rapidly and simultaneously open up several images on their web-browser, adjust the intensity min/max cutoff or its scaling function, and zoom level, apply color-maps, view position and FITS header information, execute typically used data reduction codes on the corresponding FITS data using the FRIAA framework, and overlay tiles for source catalog objects, etc.

Effects of aquatic exercise on physical function and fitness among people with spinal cord injury: A systematic review.

PubMed

Li, Chunxiao; Khoo, Selina; Adnan, Athirah

2017-03-01

The aim of this review is to synthesize the evidence on the effects of aquatic exercise interventions on physical function and fitness among people with spinal cord injury. Six major databases were searched from inception till June 2015: MEDLINE, CINAHL, EMBASE, PsychInfo, SPORTDiscus, and Cochrane Center Register of Controlled Trials. Two reviewers independently rated methodological quality using the modified Downs and Black Scale and extracted and synthesized key findings (i.e., participant characteristics, study design, physical function and fitness outcomes, and adverse events). Eight of 276 studies met the inclusion criteria, of which none showed high research quality. Four studies assessed physical function outcomes and 4 studies evaluated aerobic fitness as outcome measures. Significant improvements on these 2 outcomes were generally found. Other physical or fitness outcomes including body composition, muscular strength, and balance were rarely reported. There is weak evidence supporting aquatic exercise training to improve physical function and aerobic fitness among adults with spinal cord injury. Suggestions for future research include reporting details of exercise interventions, evaluating other physical or fitness outcomes, and improving methodological quality.

Fitness, fatness, cognition, behavior, and academic achievement among overweight children: Do cross-sectional associations correspond to exercise trial outcomes?

PubMed Central

Davis, Catherine L.; Cooper, Stephanie

2011-01-01

Background This study examined associations of fitness and fatness with cognitive processes, academic achievement, and behavior, independent of demographic factors, at the baseline of an exercise trial. Methods Overweight, sedentary but otherwise healthy 7–11 year olds (N=170) participated in a study of health, cognition and achievement in the Augusta, GA area from 2003–2006. Children underwent evaluations of fatness and fitness, psychological assessments of cognition and academic achievement, and behavior ratings by parents and teachers. Partial correlations examined associations of fitness and fatness with cognitive and achievement scores and behavior ratings, controlling for demographic factors. Results Fitness was associated with better cognition, achievement and behavior, and fatness with worse scores. Specifically, executive function, mathematics and reading achievement, and parent ratings of child behavior were related to fitness and fatness. Teacher ratings were related to fitness. Conclusion These results extend prior studies by providing reliable, standardized measures of cognitive processes, achievement, and behavior in relation to detailed measures of fitness and fatness. However, cross-sectional associations do not necessarily indicate that improving one factor, such as fatness or fitness, will result in improvements in factors that were associated with it. Thus, randomized clinical trials are necessary to determine the effects of interventions. PMID:21281668

Fitness, fatness, cognition, behavior, and academic achievement among overweight children: do cross-sectional associations correspond to exercise trial outcomes?

PubMed

Davis, Catherine L; Cooper, Stephanie

2011-06-01

This study examined associations of fitness and fatness with cognitive processes, academic achievement, and behavior, independent of demographic factors, at the baseline of an exercise trial. Overweight, sedentary but otherwise healthy 7-11 year olds (N=170) participated in a study of health, cognition and achievement in the Augusta, GA area from 2003-2006. Children underwent evaluations of fatness and fitness, psychological assessments of cognition and academic achievement, and behavior ratings by parents and teachers. Partial correlations examined associations of fitness and fatness with cognitive and achievement scores and behavior ratings, controlling for demographic factors. Fitness was associated with better cognition, achievement and behavior, and fatness with worse scores. Specifically, executive function, mathematics and reading achievement, and parent ratings of child behavior were related to fitness and fatness. Teacher ratings were related to fitness. These results extend prior studies by providing reliable, standardized measures of cognitive processes, achievement, and behavior in relation to detailed measures of fitness and fatness. However, cross-sectional associations do not necessarily indicate that improving one factor, such as fatness or fitness, will result in improvements in factors that were associated with it. Thus, randomized clinical trials are necessary to determine the effects of interventions. Copyright © 2011. Published by Elsevier Inc.

A Patch Density Recommendation based on Convergence Studies for Vehicle Panel Vibration Response resulting from Excitation by a Diffuse Acoustic Field

NASA Technical Reports Server (NTRS)

Smith, Andrew; LaVerde, Bruce; Jones, Douglas; Towner, Robert; Hunt, Ron

2013-01-01

Fluid structural interaction problems that estimate panel vibration from an applied pressure field excitation are quite dependent on the spatial correlation of the pressure field. There is a danger of either over estimating a low frequency response or under predicting broad band panel response in the more modally dense bands if the pressure field spatial correlation is not accounted for adequately. Even when the analyst elects to use a fitted function for the spatial correlation an error may be introduced if the choice of patch density is not fine enough to represent the more continuous spatial correlation function throughout the intended frequency range of interest. Both qualitative and quantitative illustrations evaluating the adequacy of different patch density assumptions to approximate the fitted spatial correlation function are provided. The actual response of a typical vehicle panel system is then evaluated in a convergence study where the patch density assumptions are varied over the same finite element model. The convergence study results are presented illustrating the impact resulting from a poor choice of patch density. The fitted correlation function used in this study represents a Diffuse Acoustic Field (DAF) excitation of the panel to produce vibration response.

Domain Shuffling in a Sensor Protein Contributed to the Evolution of Insect Pathogenicity in Plant-Beneficial Pseudomonas protegens

PubMed Central

Kupferschmied, Peter; Péchy-Tarr, Maria; Imperiali, Nicola; Maurhofer, Monika; Keel, Christoph

2014-01-01

Pseudomonas protegens is a biocontrol rhizobacterium with a plant-beneficial and an insect pathogenic lifestyle, but it is not understood how the organism switches between the two states. Here, we focus on understanding the function and possible evolution of a molecular sensor that enables P. protegens to detect the insect environment and produce a potent insecticidal toxin specifically during insect infection but not on roots. By using quantitative single cell microscopy and mutant analysis, we provide evidence that the sensor histidine kinase FitF is a key regulator of insecticidal toxin production. Our experimental data and bioinformatic analyses indicate that FitF shares a sensing domain with DctB, a histidine kinase regulating carbon uptake in Proteobacteria. This suggested that FitF has acquired its specificity through domain shuffling from a common ancestor. We constructed a chimeric DctB-FitF protein and showed that it is indeed functional in regulating toxin expression in P. protegens. The shuffling event and subsequent adaptive modifications of the recruited sensor domain were critical for the microorganism to express its potent insect toxin in the observed host-specific manner. Inhibition of the FitF sensor during root colonization could explain the mechanism by which P. protegens differentiates between the plant and insect host. Our study establishes FitF of P. protegens as a prime model for molecular evolution of sensor proteins and bacterial pathogenicity. PMID:24586167

Declining lymphoid progenitor fitness promotes aging-associated leukemogenesis.

PubMed

Henry, Curtis J; Marusyk, Andriy; Zaberezhnyy, Vadym; Adane, Biniam; DeGregori, James

2010-12-14

Aging is associated with the functional decline of cells, tissues, and organs. At the same time, age is the single most important prognostic factor in the development of most human cancers, including chronic myelogenous and acute lymphoblastic leukemias initiated by Bcr-Abl oncogenic translocations. Prevailing paradigms attribute the association between aging and cancers to the accumulation of oncogenic mutations over time, because the accrual of oncogenic events is thought to be the rate-limiting step in initiation and progression of cancers. Conversely, aging-associated functional decline caused by both cell-autonomous and non-cell-autonomous mechanisms is likely to reduce the fitness of stem and progenitor cell populations. This reduction in fitness should be conducive for increased selection of oncogenic mutations that can at least partially alleviate fitness defects, thereby promoting the initiation of cancers. We tested this hypothesis using mouse hematopoietic models. Our studies indicate that the dramatic decline in the fitness of aged B-lymphopoiesis coincides with altered receptor-associated kinase signaling. We further show that Bcr-Abl provides a much greater competitive advantage to old B-lymphoid progenitors compared with young progenitors, coinciding with restored kinase signaling pathways, and that this enhanced competitive advantage translates into increased promotion of Bcr-Abl-driven leukemias. Moreover, impairing IL-7-mediated signaling is sufficient to promote selection for Bcr-Abl-expressing B progenitors. These studies support an unappreciated causative link between aging and cancer: increased selection of oncogenic mutations as a result of age-dependent alterations of the fitness landscape.

Contextual modulation of social and endocrine correlates of fitness: insights from the life history of a sex changing fish

PubMed Central

Pradhan, Devaleena S.; Solomon-Lane, Tessa K.; Grober, Matthew S.

2015-01-01

Steroid hormones are critical regulators of reproductive life history, and the steroid sensitive traits (morphology, behavior, physiology) associated with particular life history stages can have substantial fitness consequences for an organism. Hormones, behavior and fitness are reciprocally associated and can be used in an integrative fashion to understand how the environment impacts organismal function. To address the fitness component, we highlight the importance of using reliable proxies of reproductive success when studying proximate regulation of reproductive phenotypes. To understand the mechanisms by which the endocrine system regulates phenotype, we discuss the use of particular endocrine proxies and the need for appropriate functional interpretation of each. Lastly, in any experimental paradigm, the responses of animals vary based on the subtle differences in environmental and social context and this must also be considered. We explore these different levels of analyses by focusing on the fascinating life history transitions exhibited by the bi-directionally hermaphroditic fish, Lythrypnus dalli. Sex changing fish are excellent models for providing a deeper understanding of the fitness consequences associated with behavioral and endocrine variation. We close by proposing that local regulation of steroids is one potential mechanism that allows for the expression of novel phenotypes that can be characteristic of specific life history stages. A comparative species approach will facilitate progress in understanding the diversity of mechanisms underlying the contextual regulation of phenotypes and their associated fitness correlates. PMID:25691855

Contextual modulation of social and endocrine correlates of fitness: insights from the life history of a sex changing fish.

PubMed

Pradhan, Devaleena S; Solomon-Lane, Tessa K; Grober, Matthew S

2015-01-01

Steroid hormones are critical regulators of reproductive life history, and the steroid sensitive traits (morphology, behavior, physiology) associated with particular life history stages can have substantial fitness consequences for an organism. Hormones, behavior and fitness are reciprocally associated and can be used in an integrative fashion to understand how the environment impacts organismal function. To address the fitness component, we highlight the importance of using reliable proxies of reproductive success when studying proximate regulation of reproductive phenotypes. To understand the mechanisms by which the endocrine system regulates phenotype, we discuss the use of particular endocrine proxies and the need for appropriate functional interpretation of each. Lastly, in any experimental paradigm, the responses of animals vary based on the subtle differences in environmental and social context and this must also be considered. We explore these different levels of analyses by focusing on the fascinating life history transitions exhibited by the bi-directionally hermaphroditic fish, Lythrypnus dalli. Sex changing fish are excellent models for providing a deeper understanding of the fitness consequences associated with behavioral and endocrine variation. We close by proposing that local regulation of steroids is one potential mechanism that allows for the expression of novel phenotypes that can be characteristic of specific life history stages. A comparative species approach will facilitate progress in understanding the diversity of mechanisms underlying the contextual regulation of phenotypes and their associated fitness correlates.

Talking to patients with fibromyalgia about physical activity and exercise.

PubMed

Rooks, Daniel S

2008-03-01

The purpose of this article is to describe the application of basic exercise principles to individuals with fibromyalgia to encourage clinicians to discuss with their patients ways of becoming more physically active. The goals of increased physical activity and exercise for individuals with fibromyalgia are to improve or maintain general fitness, physical function, emotional well being, symptoms and overall health, and provide them with a feeling of control over their well being. Describing ways of increasing activity through home, work and leisure-related tasks or exercise provides a universal approach to increasing physical activity that applies to individuals with fibromyalgia and fits a counseling model of health behavior familiar to clinicians. The patient-clinician relationship provides a unique opportunity for health professionals to counsel individuals with fibromyalgia to become and remain more physically active. Regular physical activity and exercise has numerous physical, psychological, and functional benefits for individuals with fibromyalgia and should be included in treatment plans. Clinicians can help patients adopt a more physically active lifestyle through targeted discussions, support and consistent follow up.

Comprehensive Hearing Aid Intervention at a Free Subspecialty Clinic.

PubMed

Wertz, Aileen P; Mannarelli, Gregory; Shuman, Andrew G; McKean, Erin L

2017-09-01

Providing a model of a comprehensive free audiologic program may assist other health care professionals in developing their own similar program. To describe the structure, feasibility, and outcomes of a free subspecialty clinic providing hearing aids to develop a paradigm for other programs interested in implementing similar projects. A retrospective case series was conducted from September 1, 2013, through March 31, 2016. In a partnership between a free independent clinic for indigent patients and an academic medical center, 54 indigent patients were referred to the clinic for audiograms. A total of 50 of these patients had results of audiograms available for review and were therefore included in the study; 34 of these 50 patients were determined to be eligible for hearing aid fitting based on audiometric results. Free audiometric testing, hearing aid fitting, and hearing aid donation. The number of hearing aids donated, number of eligible patients identified, number of patients fitted with hearing aids, and work effort (hours) and start-up costs associated with implementation of this program were quantified. A total of 54 patients (31 women [57.4%] and 23 men [42.6%]; median age, 61 years; range, 33-85 years) had audiograms performed, and 84 hearing aids were donated to the program. The patients were provided with free audiograms, hearing aid molds, and hearing aid programming, as well as follow-up appointments to ensure continued proper functioning of their hearing aids. Since 2013, a total of 34 patients have been determined to be eligible for the free program and were offered hearing aid services. Of these, 20 patients (59%) have been fitted or are being fitted with free hearing aids. The value of services provided is estimated to be $2260 per patient. It is feasible to provide free, comprehensive audiologic care, including hearing aids and fitting, in a well-established, free clinic model. The opportunity for indigent patients to use hearing aids at minimal personal cost is a major step forward in improving access to high-quality care.

Powered wheel for aircraft

NASA Technical Reports Server (NTRS)

Long, M. J.; Irick, S. C.; Van Ausdal, R. K.

1977-01-01

Single integral unit includes motor, gearbox, and clutch. Device has two-speed capability, fits within aerodynamic contours of aircraft, operates with onboard power source, does not interfere with normal landing gear functions, reduces use of regular brakes in congested areas, and provides locomotion and supplementary braking capability.

The rhizosphere microbiota of plant invaders: an overview of recent advances in the microbiomics of invasive plants

PubMed Central

Coats, Vanessa C.; Rumpho, Mary E.

2014-01-01

Plants in terrestrial systems have evolved in direct association with microbes functioning as both agonists and antagonists of plant fitness and adaptability. As such, investigations that segregate plants and microbes provide only a limited scope of the biotic interactions that dictate plant community structure and composition in natural systems. Invasive plants provide an excellent working model to compare and contrast the effects of microbial communities associated with natural plant populations on plant fitness, adaptation, and fecundity. The last decade of DNA sequencing technology advancements opened the door to microbial community analysis, which has led to an increased awareness of the importance of an organism’s microbiome and the disease states associated with microbiome shifts. Employing microbiome analysis to study the symbiotic networks associated with invasive plants will help us to understand what microorganisms contribute to plant fitness in natural systems, how different soil microbial communities impact plant fitness and adaptability, specificity of host–microbe interactions in natural plant populations, and the selective pressures that dictate the structure of above-ground and below-ground biotic communities. This review discusses recent advances in invasive plant biology that have resulted from microbiome analyses as well as the microbial factors that direct plant fitness and adaptability in natural systems. PMID:25101069

Executive Control Mediates the Association Between Aerobic Fitness and Emotion Regulation in Preadolescent Children.

PubMed

Lott, Mark A; Jensen, Chad D

2017-03-01

This study evaluated direct and indirect associations between aerobic fitness, executive control, and emotion regulation among a community sample of preadolescent children. Two-hundred and seventy-eight children aged 8-12 years completed measures of aerobic fitness (Progressive Aerobic Cardiovascular Endurance Run) and executive control (Stroop Test). Parents completed questionnaires assessing child emotion regulation and executive control (Emotion Regulation Checklist; Early Adolescent Temperament Questionnaire). We evaluated associations between these constructs using structural equation modeling. Study findings supported a moderate direct association between childhood aerobic fitness and executive control, a strong direct negative association between executive control and emotion regulation, and a moderate indirect association between aerobic fitness and emotion regulation through executive control. These findings provide preliminary evidence that executive control functions as a mediator between aerobic fitness and emotion regulation and may help explain the mechanism by which aerobic exercise influences emotional well-being among preadolescent children. © The Author 2016. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Functional Interdependence Theory: An Evolutionary Account of Social Situations.

PubMed

Balliet, Daniel; Tybur, Joshua M; Van Lange, Paul A M

2017-11-01

Social interactions are characterized by distinct forms of interdependence, each of which has unique effects on how behavior unfolds within the interaction. Despite this, little is known about the psychological mechanisms that allow people to detect and respond to the nature of interdependence in any given interaction. We propose that interdependence theory provides clues regarding the structure of interdependence in the human ancestral past. In turn, evolutionary psychology offers a framework for understanding the types of information processing mechanisms that could have been shaped under these recurring conditions. We synthesize and extend these two perspectives to introduce a new theory: functional interdependence theory (FIT). FIT can generate testable hypotheses about the function and structure of the psychological mechanisms for inferring interdependence. This new perspective offers insight into how people initiate and maintain cooperative relationships, select social partners and allies, and identify opportunities to signal social motives.

Evaluation of statistical distributions to analyze the pollution of Cd and Pb in urban runoff.

PubMed

Toranjian, Amin; Marofi, Safar

2017-05-01

Heavy metal pollution in urban runoff causes severe environmental damage. Identification of these pollutants and their statistical analysis is necessary to provide management guidelines. In this study, 45 continuous probability distribution functions were selected to fit the Cd and Pb data in the runoff events of an urban area during October 2014-May 2015. The sampling was conducted from the outlet of the city basin during seven precipitation events. For evaluation and ranking of the functions, we used the goodness of fit Kolmogorov-Smirnov and Anderson-Darling tests. The results of Cd analysis showed that Hyperbolic Secant, Wakeby and Log-Pearson 3 are suitable for frequency analysis of the event mean concentration (EMC), the instantaneous concentration series (ICS) and instantaneous concentration of each event (ICEE), respectively. In addition, the LP3, Wakeby and Generalized Extreme Value functions were chosen for the EMC, ICS and ICEE related to Pb contamination.

Learning curves in highly skilled chess players: a test of the generality of the power law of practice.

PubMed

Howard, Robert W

2014-09-01

The power law of practice holds that a power function best interrelates skill performance and amount of practice. However, the law's validity and generality are moot. Some researchers argue that it is an artifact of averaging individual exponential curves while others question whether the law generalizes to complex skills and to performance measures other than response time. The present study tested the power law's generality to development over many years of a very complex cognitive skill, chess playing, with 387 skilled participants, most of whom were grandmasters. A power or logarithmic function best fit grouped data but individuals showed much variability. An exponential function usually was the worst fit to individual data. Groups differing in chess talent were compared and a power function best fit the group curve for the more talented players while a quadratic function best fit that for the less talented. After extreme amounts of practice, a logarithmic function best fit grouped data but a quadratic function best fit most individual curves. Individual variability is great and the power law or an exponential law are not the best descriptions of individual chess skill development. Copyright © 2014 Elsevier B.V. All rights reserved.

The effects of loaded and unloaded high-velocity resistance training on functional fitness among community-dwelling older adults.

PubMed

Glenn, Jordan M; Gray, Michelle; Binns, Ashley

2015-11-01

Physical function declines up to 4% per year after the age of 65. High-velocity training is important for maintaining muscular power and ultimately, physical function; however, whether performing high-velocity training without external resistance increases functional fitness among older adults remains unclear. The purpose of this investigation was to evaluate loaded and unloaded high-velocity training on lower body muscular power and functional fitness in older adults. Fifty-seven community-dwelling older adults (n = 16 males, n = 41 females) participated in this study. Inclusion criteria comprised ≥65 years of age, ≥24 on the Mini-mental state examination and no falls within past year. Two groups completed a 20-week high-velocity training intervention. The non-weighted group (UNLOAD, n = 27) performed the protocol without external load while the intervention group (LOAD, n = 30) used external loads via exercise machines. Functional fitness was assessed using the Short Physical Performance Battery (SPPB), Senior Fitness Test (SFT), hand-grip and lower body power measures. Multivariate ANOVA revealed that both groups had significant improvements for average (17.21%) and peak (9.26%) lower body power, along with the SFT arm curl (16.94%), chair stand (20.10%) and 8 ft. up-and-go (15.67%). Improvements were also noticed for SPPB 8 ft. walk (25.21%). However, improvements for all functional fitness measures were independent of training group. Unloaded high-velocity training increased functional fitness and power the same as loaded training. The ability of high-velocity movements to elicit gains in functional fitness without external loads may help health professionals develop fitness programs when time/space is limiting factor. © The Author 2015. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Differences in Sustained Attention Capacity as a Function of Aerobic Fitness.

PubMed

Luque-Casado, Antonio; Perakakis, Pandelis; Hillman, Charles H; Kao, Shih-Chun; Llorens, Francesc; Guerra, Pedro; Sanabria, Daniel

2016-05-01

We investigated the relationship between aerobic fitness and sustained attention capacity by comparing task performance and brain function, by means of event-related potentials (ERP), in high- and low-fit young adults. Two groups of participants (22 higher-fit and 20 lower-fit) completed a 60-min version of the Psychomotor Vigilance Task (PVT). Behavioral (i.e., reaction time) and electrophysiological (ERP) (i.e., contingent negative variation and P3) were obtained and analyzed as a function of time-on-task. A submaximal cardiorespiratory fitness test confirmed the between-groups difference in terms of aerobic fitness. The results revealed shorter reaction time in higher-fit than in lower-fit participants in the first 36 min of the task. This was accompanied by larger contingent negative variation amplitude in the same period of the task in higher-fit than in lower-fit group. Crucially, higher-fit participants maintained larger P3 amplitude throughout the task compared to lower-fit, who showed a reduction in the P3 magnitude over time. Higher fitness was related to neuroelectric activity suggestive of better overall sustained attention demonstrating a better ability to allocate attentional resources over time. Moreover, higher fitness was related to enhanced response preparation in the first part of the task. Taken together, the current data set demonstrated a positive association between aerobic fitness, sustained attention, and response preparation.

Adaptation in Tunably Rugged Fitness Landscapes: The Rough Mount Fuji Model

PubMed Central

Neidhart, Johannes; Szendro, Ivan G.; Krug, Joachim

2014-01-01

Much of the current theory of adaptation is based on Gillespie’s mutational landscape model (MLM), which assumes that the fitness values of genotypes linked by single mutational steps are independent random variables. On the other hand, a growing body of empirical evidence shows that real fitness landscapes, while possessing a considerable amount of ruggedness, are smoother than predicted by the MLM. In the present article we propose and analyze a simple fitness landscape model with tunable ruggedness based on the rough Mount Fuji (RMF) model originally introduced by Aita et al. in the context of protein evolution. We provide a comprehensive collection of results pertaining to the topographical structure of RMF landscapes, including explicit formulas for the expected number of local fitness maxima, the location of the global peak, and the fitness correlation function. The statistics of single and multiple adaptive steps on the RMF landscape are explored mainly through simulations, and the results are compared to the known behavior in the MLM model. Finally, we show that the RMF model can explain the large number of second-step mutations observed on a highly fit first-step background in a recent evolution experiment with a microvirid bacteriophage. PMID:25123507

Error catastrophe and phase transition in the empirical fitness landscape of HIV

NASA Astrophysics Data System (ADS)

Hart, Gregory R.; Ferguson, Andrew L.

2015-03-01

We have translated clinical sequence databases of the p6 HIV protein into an empirical fitness landscape quantifying viral replicative capacity as a function of the amino acid sequence. We show that the viral population resides close to a phase transition in sequence space corresponding to an "error catastrophe" beyond which there is lethal accumulation of mutations. Our model predicts that the phase transition may be induced by drug therapies that elevate the mutation rate, or by forcing mutations at particular amino acids. Applying immune pressure to any combination of killer T-cell targets cannot induce the transition, providing a rationale for why the viral protein can exist close to the error catastrophe without sustaining fatal fitness penalties due to adaptive immunity.

Laser plasma x-ray line spectra fitted using the Pearson VII function

NASA Astrophysics Data System (ADS)

Michette, A. G.; Pfauntsch, S. J.

2000-05-01

The Pearson VII function, which is more general than the Gaussian, Lorentzian and other profiles, is used to fit the x-ray spectral lines produced in a laser-generated plasma, instead of the more usual, but computationally expensive, Voigt function. The mean full-width half-maximum of the fitted lines is 0.102+/-0.014 nm, entirely consistent with the value expected from geometrical considerations, and the fitted line profiles are generally inconsistent with being either Lorentzian or Gaussian.

Bivariate drought frequency analysis using the copula method

NASA Astrophysics Data System (ADS)

Mirabbasi, Rasoul; Fakheri-Fard, Ahmad; Dinpashoh, Yagob

2012-04-01

Droughts are major natural hazards with significant environmental and economic impacts. In this study, two-dimensional copulas were applied to the analysis of the meteorological drought characteristics of the Sharafkhaneh gauge station, located in the northwest of Iran. Two major drought characteristics, duration and severity, as defined by the standardized precipitation index, were abstracted from observed drought events. Since drought duration and severity exhibited a significant correlation and since they were modeled using different distributions, copulas were used to construct the joint distribution function of the drought characteristics. The parameter of copulas was estimated using the method of the Inference Function for Margins. Several copulas were tested in order to determine the best data fit. According to the error analysis and the tail dependence coefficient, the Galambos copula provided the best fit for the observed drought data. Some bivariate probabilistic properties of droughts, based on the derived copula-based joint distribution, were also investigated. These probabilistic properties can provide useful information for water resource planning and management.

A CAD System for Evaluating Footwear Fit

NASA Astrophysics Data System (ADS)

Savadkoohi, Bita Ture; de Amicis, Raffaele

With the great growth in footwear demand, the footwear manufacturing industry, for achieving commercial success, must be able to provide the footwear that fulfills consumer's requirement better than it's competitors. Accurate fitting for shoes is an important factor in comfort and functionality. Footwear fitter measurement have been using manual measurement for a long time, but the development of 3D acquisition devices and the advent of powerful 3D visualization and modeling techniques, automatically analyzing, searching and interpretation of the models have now made automatic determination of different foot dimensions feasible. In this paper, we proposed an approach for finding footwear fit within the shoe last data base. We first properly aligned the 3D models using "Weighted" Principle Component Analysis (WPCA). After solving the alignment problem we used an efficient algorithm for cutting the 3D model in order to find the footwear fit from shoe last data base.

Effects of aquatic exercise on physical function and fitness among people with spinal cord injury

PubMed Central

Li, Chunxiao; Khoo, Selina; Adnan, Athirah

2017-01-01

Abstract Objective: The aim of this review is to synthesize the evidence on the effects of aquatic exercise interventions on physical function and fitness among people with spinal cord injury. Data source: Six major databases were searched from inception till June 2015: MEDLINE, CINAHL, EMBASE, PsychInfo, SPORTDiscus, and Cochrane Center Register of Controlled Trials. Study appraisal and synthesis methods: Two reviewers independently rated methodological quality using the modified Downs and Black Scale and extracted and synthesized key findings (i.e., participant characteristics, study design, physical function and fitness outcomes, and adverse events). Results: Eight of 276 studies met the inclusion criteria, of which none showed high research quality. Four studies assessed physical function outcomes and 4 studies evaluated aerobic fitness as outcome measures. Significant improvements on these 2 outcomes were generally found. Other physical or fitness outcomes including body composition, muscular strength, and balance were rarely reported. Conclusions and implications of key findings: There is weak evidence supporting aquatic exercise training to improve physical function and aerobic fitness among adults with spinal cord injury. Suggestions for future research include reporting details of exercise interventions, evaluating other physical or fitness outcomes, and improving methodological quality. PMID:28296754

Fermitins, the Orthologs of Mammalian Kindlins, Regulate the Development of a Functional Cardiac Syncytium in Drosophila melanogaster

PubMed Central

Catterson, James H.; Heck, Margarete M. S.; Hartley, Paul S.

2013-01-01

The vertebrate Kindlins are an evolutionarily conserved family of proteins critical for integrin signalling and cell adhesion. Kindlin-2 (KIND2) is associated with intercalated discs in mice, suggesting a role in cardiac syncytium development; however, deficiency of Kind2 leads to embryonic lethality. Morpholino knock-down of Kind2 in zebrafish has a pleiotropic effect on development that includes the heart. It therefore remains unclear whether cardiomyocyte Kind2 expression is required for cardiomyocyte junction formation and the development of normal cardiac function. To address this question, the expression of Fermitin 1 and Fermitin 2 (Fit1, Fit2), the two Drosophila orthologs of Kind2, was silenced in Drosophila cardiomyocytes. Heart development was assessed in adult flies by immunological methods and videomicroscopy. Silencing both Fit1 and Fit2 led to a severe cardiomyopathy characterised by the failure of cardiomyocytes to develop as a functional syncytium and loss of synchrony between cardiomyocytes. A null allele of Fit1 was generated but this had no impact on the heart. Similarly, the silencing of Fit2 failed to affect heart function. In contrast, the silencing of Fit2 in the cardiomyocytes of Fit1 null flies disrupted syncytium development, leading to severe cardiomyopathy. The data definitively demonstrate a role for Fermitins in the development of a functional cardiac syncytium in Drosophila. The findings also show that the Fermitins can functionally compensate for each other in order to control syncytium development. These findings support the concept that abnormalities in cardiomyocyte KIND2 expression or function may contribute to cardiomyopathies in humans. PMID:23690969

Improving physical fitness of individuals with intellectual and developmental disability through a Virtual Reality Intervention Program.

PubMed

Lotan, Meir; Yalon-Chamovitz, Shira; Weiss, Patrice L Tamar

2009-01-01

Individuals with intellectual and developmental disabilities (IDD) are in need of effective physical fitness training programs. The aim was to test the effectiveness of a Virtual Reality (VR)-based exercise program in improving the physical fitness of adults with IDD. A research group (N=30; mean age=52.3+/-5.8 years; moderate IDD level) was matched for age, IDD level and functional abilities with a control group (N=30, mean age=54.3+/-5.4 years). A 5-6 week fitness program consisting of two 30 min sessions per week included game-like exercises provided by the Sony PlayStation II EyeToy VR system. Changes in physical fitness were monitored by the Energy Expenditure Index (EEI), the modified 12 min walk/run and the Total Heart Beat Index (THBI). Significant (p<0.05) improvements in physical fitness were demonstrated for the research group in comparison to the control group for the Modified Cooper test and the THBI but not for the EEI test. The EEI, Modified Cooper and THBI tests were found feasible to evaluate physical fitness levels and change of individuals with IDD under clinical conditions. VR technology intervention was suitable for adults with IDD and resulted in significant improvements in the physical fitness levels of the participants.

The QDP/PLT user's guide

NASA Technical Reports Server (NTRS)

Tennant, Allyn F.

1991-01-01

PLT is a high level plotting package. A Programmer can create a default plot suited for the data being displayed. At run times, users can then interact with the plot overriding any or all of these defaults. The user is also provided the capability to fit functions to the displayed data. This ability to display, interact with, and to fit the data make PLT a useful tool in the analysis of data. The Quick and Dandy Plotter (QDP) program will read ASCII text files that contain PLT commands and data. Thus, QDP provides and easy way to use the PLT software QPD files provide a convenient way to exchange data. The QPD/PLT software is written in standard FORTRAN 77 and has been ported to VAX VMS, SUN UNIX, IBM AIX, NeXT NextStep, and MS-DOS systems.

seawaveQ: an R package providing a model and utilities for analyzing trends in chemical concentrations in streams with a seasonal wave (seawave) and adjustment for streamflow (Q) and other ancillary variables

USGS Publications Warehouse

Ryberg, Karen R.; Vecchia, Aldo V.

2013-01-01

The seawaveQ R package fits a parametric regression model (seawaveQ) to pesticide concentration data from streamwater samples to assess variability and trends. The model incorporates the strong seasonality and high degree of censoring common in pesticide data and users can incorporate numerous ancillary variables, such as streamflow anomalies. The model is fitted to pesticide data using maximum likelihood methods for censored data and is robust in terms of pesticide, stream location, and degree of censoring of the concentration data. This R package standardizes this methodology for trend analysis, documents the code, and provides help and tutorial information, as well as providing additional utility functions for plotting pesticide and other chemical concentration data.

Relationship of Sit-to-Stand Lower-Body Power With Functional Fitness Measures Among Older Adults With and Without Sarcopenia.

PubMed

Glenn, Jordan M; Gray, Michelle; Binns, Ashley

When evaluating health in older adults, batteries of tests are typically utilized to assess functional fitness. Unfortunately, physician's visits are time-sensitive, and it may be important to develop faster methods to assess functional fitness that can be utilized in professional or clinical settings. Therefore, the purpose of this investigation was to examine the relationship of sit-to-stand (STS) power generated through the STS task with previously established measures of functional fitness, specifically strength, endurance, speed, agility, and flexibility in older adults with and without sarcopenia. This study consisted of 57 community-dwelling older adults (n = 16 males; n = 41 females). Functional fitness was assessed using the Short Physical Performance Battery (SPPB), Senior Fitness Test, handgrip, gait speed (habitual and maximal), balance, and STS power generated via the Tendo Weightlifting Analyzer. On the basis of data distribution, second-degree polynomial (quadratic) curvilinear models (lines of best fit) were applied for the relationships of 5-time STS time with average and peak power. Zero-order correlations were evaluated between STS power and all other functional fitness measures. Older adults with sarcopenia were also identified (n = 15), and relationships were reevaluated within this subset. STS power (average and peak) was significantly (P ≤ .01) correlated with physical performance measured via previously established assessments. For average power, this was observed during the senior fitness test (6-minute walk [r = 0.39], 8-ft up-and-go [r = -0.46], arm curl [r = 0.46], and chair stand [r = 0.55]), SPPB (5-time STS time [r = -0.63] and 8-ft walk [r = -0.32]), and other independent functional fitness measures (grip strength [r = 0.65] and maximal gait speed [r = -0.31]). Similar results were observed for peak power during the senior fitness test (6-minute walk [r = 0.39], 8-ft up-and-go [r = -0.46], arm curl [r = 0.45], chair stand [r = 0.52], and sit-and-reach [r = -0.27]), SPPB (5-time STS time [r = -0.60] and 8-ft walk [r = -0.33]), and other independent functional fitness measures (grip strength [r = 0.70] and maximal gait speed [r = -0.32]). Within the sarcopenic subset, for average and peak power, respectively, significant relationships were still retained for handgrip strength (r = 0.57 and r = 0.57), 6-minute walk (r = 0.55 and r = 0.61), chair stand (r = 0.76 and r = 0.81), and 5-time STS time (r = -0.76 and r = -0.80) tests. STS power generated via the STS task significantly relates to commonly administered functional fitness measures. These relationships also appear to exist when evaluating these relationships in older adults with sarcopenia. STS power may be utilized as an independent measure of functional fitness that is feasible to incorporate in clinical settings where time and space are often limiting factors.

dftools: Distribution function fitting

NASA Astrophysics Data System (ADS)

Obreschkow, Danail

2018-05-01

dftools, written in R, finds the most likely P parameters of a D-dimensional distribution function (DF) generating N objects, where each object is specified by D observables with measurement uncertainties. For instance, if the objects are galaxies, it can fit a mass function (D=1), a mass-size distribution (D=2) or the mass-spin-morphology distribution (D=3). Unlike most common fitting approaches, this method accurately accounts for measurement in uncertainties and complex selection functions.

Function approximation and documentation of sampling data using artificial neural networks.

PubMed

Zhang, Wenjun; Barrion, Albert

2006-11-01

Biodiversity studies in ecology often begin with the fitting and documentation of sampling data. This study is conducted to make function approximation on sampling data and to document the sampling information using artificial neural network algorithms, based on the invertebrate data sampled in the irrigated rice field. Three types of sampling data, i.e., the curve species richness vs. the sample size, the curve rarefaction, and the curve mean abundance of newly sampled species vs.the sample size, are fitted and documented using BP (Backpropagation) network and RBF (Radial Basis Function) network. As the comparisons, The Arrhenius model, and rarefaction model, and power function are tested for their ability to fit these data. The results show that the BP network and RBF network fit the data better than these models with smaller errors. BP network and RBF network can fit non-linear functions (sampling data) with specified accuracy and don't require mathematical assumptions. In addition to the interpolation, BP network is used to extrapolate the functions and the asymptote of the sampling data can be drawn. BP network cost a longer time to train the network and the results are always less stable compared to the RBF network. RBF network require more neurons to fit functions and generally it may not be used to extrapolate the functions. The mathematical function for sampling data can be exactly fitted using artificial neural network algorithms by adjusting the desired accuracy and maximum iterations. The total numbers of functional species of invertebrates in the tropical irrigated rice field are extrapolated as 140 to 149 using trained BP network, which are similar to the observed richness.

HERAFitter: Open source QCD fit project

DOE PAGES

Alekhin, S.; Behnke, O.; Belov, P.; ...

2015-07-01

HERAFitter is an open-source package that provides a framework for the determination of the parton distribution functions (PDFs) of the proton and for many different kinds of analyses in Quantum Chromodynamics (QCD). It encodes results from a wide range of experimental measurements in lepton-proton deep inelastic scattering and proton-proton (proton-antiproton) collisions at hadron colliders. These are complemented with a variety of theoretical options for calculating PDF-dependent cross section predictions corresponding to the measurements. The framework covers a large number of the existing methods and schemes used for PDF determination. The data and theoretical predictions are brought together through numerous methodologicalmore » options for carrying out PDF fits and plotting tools to help visualise the results. While primarily based on the approach of collinear factorisation, HERAFitter also provides facilities for fits of dipole models and transverse-momentum dependent PDFs. The package can be used to study the impact of new precise measurements from hadron colliders. This paper describes the general structure of HERAFitter and its wide choice of options.« less

Fitting Multimeric Protein Complexes into Electron Microscopy Maps Using 3D Zernike Descriptors

PubMed Central

Esquivel-Rodríguez, Juan; Kihara, Daisuke

2012-01-01

A novel computational method for fitting high-resolution structures of multiple proteins into a cryoelectron microscopy map is presented. The method named EMLZerD generates a pool of candidate multiple protein docking conformations of component proteins, which are later compared with a provided electron microscopy (EM) density map to select the ones that fit well into the EM map. The comparison of docking conformations and the EM map is performed using the 3D Zernike descriptor (3DZD), a mathematical series expansion of three-dimensional functions. The 3DZD provides a unified representation of the surface shape of multimeric protein complex models and EM maps, which allows a convenient, fast quantitative comparison of the three dimensional structural data. Out of 19 multimeric complexes tested, near native complex structures with a root mean square deviation of less than 2.5 Å were obtained for 14 cases while medium range resolution structures with correct topology were computed for the additional 5 cases. PMID:22417139

Fitting multimeric protein complexes into electron microscopy maps using 3D Zernike descriptors.

PubMed

Esquivel-Rodríguez, Juan; Kihara, Daisuke

2012-06-14

A novel computational method for fitting high-resolution structures of multiple proteins into a cryoelectron microscopy map is presented. The method named EMLZerD generates a pool of candidate multiple protein docking conformations of component proteins, which are later compared with a provided electron microscopy (EM) density map to select the ones that fit well into the EM map. The comparison of docking conformations and the EM map is performed using the 3D Zernike descriptor (3DZD), a mathematical series expansion of three-dimensional functions. The 3DZD provides a unified representation of the surface shape of multimeric protein complex models and EM maps, which allows a convenient, fast quantitative comparison of the three-dimensional structural data. Out of 19 multimeric complexes tested, near native complex structures with a root-mean-square deviation of less than 2.5 Å were obtained for 14 cases while medium range resolution structures with correct topology were computed for the additional 5 cases.

Association between aerobic fitness and cerebrovascular function with neurocognitive functions in healthy, young adults.

PubMed

Hwang, Jungyun; Kim, Kiyoung; Brothers, R Matthew; Castelli, Darla M; Gonzalez-Lima, F

2018-05-01

Studies of the effects of physical activity on cognition suggest that aerobic fitness can improve cognitive abilities. However, the physiological mechanisms for the cognitive benefit of aerobic fitness are less well understood. We examined the association between aerobic fitness and cerebrovascular function with neurocognitive functions in healthy, young adults. Participants aged 18-29 years underwent measurements of cerebral vasomotor reactivity (CVMR) in response to rebreathing-induced hypercapnia, maximal oxygen uptake (VO 2 max) during cycle ergometry to voluntary exhaustion, and simple- and complex-neurocognitive assessments at rest. Ten subjects were identified as having low-aerobic fitness (LF < 15th fitness percentile), and twelve subjects were identified as having high-aerobic fitness (HF > 80th fitness percentile). There were no LF versus HF group differences in cerebrovascular hemodynamics during the baseline condition. Changes in middle cerebral artery blood velocity and CVMR during hypercapnia were elevated more in the HF than the LF group. Compared to the LF, the HF performed better on a complex-cognitive task assessing fluid reasoning, but not on simple attentional abilities. Statistical modeling showed that measures of VO 2 max, CVMR, and fluid reasoning were positively inter-correlated. The relationship between VO 2 max and fluid reasoning, however, did not appear to be reliably mediated by CVMR. In conclusion, a high capacity for maximal oxygen uptake among healthy, young adults was associated with greater CVMR and better fluid reasoning, implying that high-aerobic fitness may promote cerebrovascular and cognitive functioning abilities.

Aquatic Therapy: A Viable Therapeutic Recreation Intervention.

ERIC Educational Resources Information Center

Broach, Ellen; Dattilo, John

1996-01-01

Reviews literature on the effects of aquatic therapy (swimming and exercise) to improve function. Research shows that aquatic therapy has numerous psychological and physical benefits, and it supports the belief that participation can provide a realistic solution to maintaining physical fitness and rehabilitation goals while engaging in enjoyable…

Comparison of statistical sampling methods with ScannerBit, the GAMBIT scanning module

NASA Astrophysics Data System (ADS)

Martinez, Gregory D.; McKay, James; Farmer, Ben; Scott, Pat; Roebber, Elinore; Putze, Antje; Conrad, Jan

2017-11-01

We introduce ScannerBit, the statistics and sampling module of the public, open-source global fitting framework GAMBIT. ScannerBit provides a standardised interface to different sampling algorithms, enabling the use and comparison of multiple computational methods for inferring profile likelihoods, Bayesian posteriors, and other statistical quantities. The current version offers random, grid, raster, nested sampling, differential evolution, Markov Chain Monte Carlo (MCMC) and ensemble Monte Carlo samplers. We also announce the release of a new standalone differential evolution sampler, Diver, and describe its design, usage and interface to ScannerBit. We subject Diver and three other samplers (the nested sampler MultiNest, the MCMC GreAT, and the native ScannerBit implementation of the ensemble Monte Carlo algorithm T-Walk) to a battery of statistical tests. For this we use a realistic physical likelihood function, based on the scalar singlet model of dark matter. We examine the performance of each sampler as a function of its adjustable settings, and the dimensionality of the sampling problem. We evaluate performance on four metrics: optimality of the best fit found, completeness in exploring the best-fit region, number of likelihood evaluations, and total runtime. For Bayesian posterior estimation at high resolution, T-Walk provides the most accurate and timely mapping of the full parameter space. For profile likelihood analysis in less than about ten dimensions, we find that Diver and MultiNest score similarly in terms of best fit and speed, outperforming GreAT and T-Walk; in ten or more dimensions, Diver substantially outperforms the other three samplers on all metrics.

Aerobic fitness, hippocampal viscoelasticity, and relational memory performance

PubMed Central

Schwarb, Hillary; Johnson, Curtis L.; Daugherty, Ana M.; Hillman, Charles H.; Kramer, Arthur F.; Cohen, Neal J.; Barbey, Aron K.

2017-01-01

The positive relationship between hippocampal structure, aerobic fitness, and memory performance is often observed among children and older adults; but evidence of this relationship among young adults, for whom the hippocampus is neither developing nor atrophying, is less consistent. Studies have typically relied on hippocampal volumetry (a gross proxy of tissue composition) to assess individual differences in hippocampal structure. While volume is not specific to microstructural tissue characteristics, microstructural differences in hippocampal integrity may exist even among healthy young adults when volumetric differences are not diagnostic of tissue health or cognitive function. Magnetic resonance elastography (MRE) is an emerging noninvasive imaging technique for measuring viscoelastic tissue properties and provides quantitative measures of tissue integrity. We have previously demonstrated that individual differences in hippocampal viscoelasticity are related to performance on a relational memory task; however, little is known about health correlates to this novel measure. In the current study, we investigated the relationship between hippocampal viscoelasticity and cardiovascular health, and their mutual effect on relational memory in a group of healthy young adults (N=51). We replicated our previous finding that hippocampal viscoelasticity correlates with relational memory performance. We extend this work by demonstrating that better aerobic fitness, as measured by VO2max, was associated with hippocampal viscoelasticity that mediated the benefits of fitness on memory function. Hippocampal volume, however, did not account for individual differences in memory. Therefore, these data suggest that hippocampal viscoelasticity may provide a more sensitive measure to microstructural tissue organization and its consequences to cognition among healthy young adults. PMID:28366763

Phonon scattering in nanoscale systems: lowest order expansion of the current and power expressions

NASA Astrophysics Data System (ADS)

Paulsson, Magnus; Frederiksen, Thomas; Brandbyge, Mads

2006-04-01

We use the non-equilibrium Green's function method to describe the effects of phonon scattering on the conductance of nano-scale devices. Useful and accurate approximations are developed that both provide (i) computationally simple formulas for large systems and (ii) simple analytical models. In addition, the simple models can be used to fit experimental data and provide physical parameters.

Capsule Production and Glucose Metabolism Dictate Fitness during Serratia marcescens Bacteremia.

PubMed

Anderson, Mark T; Mitchell, Lindsay A; Zhao, Lili; Mobley, Harry L T

2017-05-23

Serratia marcescens is an opportunistic pathogen that causes a range of human infections, including bacteremia, keratitis, wound infections, and urinary tract infections. Compared to other members of the Enterobacteriaceae family, the genetic factors that facilitate Serratia proliferation within the mammalian host are less well defined. An in vivo screen of transposon insertion mutants identified 212 S. marcescens fitness genes that contribute to bacterial survival in a murine model of bloodstream infection. Among those identified, 11 genes were located within an 18-gene cluster encoding predicted extracellular polysaccharide biosynthesis proteins. A mutation in the wzx gene contained within this locus conferred a loss of fitness in competition infections with the wild-type strain and a reduction in extracellular uronic acids correlating with capsule loss. A second gene, pgm , encoding a phosphoglucomutase exhibited similar capsule-deficient phenotypes, linking central glucose metabolism with capsule production and fitness of Serratia during mammalian infection. Further evidence of the importance of central metabolism was obtained with a pfkA glycolytic mutant that demonstrated reduced replication in human serum and during murine infection. An MgtB magnesium transporter homolog was also among the fitness factors identified, and an S. marcescens mgtB mutant exhibited decreased growth in defined medium containing low concentrations of magnesium and was outcompeted ~10-fold by wild-type bacteria in mice. Together, these newly identified genes provide a more complete understanding of the specific requirements for S. marcescens survival in the mammalian host and provide a framework for further investigation of the means by which S. marcescens causes opportunistic infections. IMPORTANCE Serratia marcescens is a remarkably prolific organism that replicates in diverse environments, including as an opportunistic pathogen in human bacteremia. The genetic requirements for S. marcescens survival in the mammalian bloodstream were defined in this work by transposon insertion sequencing. In total, 212 genes that contribute to bacterial fitness were identified. When sorted via biological function, two of the major fitness categories identified herein were genes encoding capsule polysaccharide biogenesis functions and genes involved in glucose utilization. Further investigation determined that certain glucose metabolism fitness genes are also important for the generation of extracellular polysaccharides. Together, these results identify critical biological processes that allow S. marcescens to colonize the mammalian bloodstream. Copyright © 2017 Anderson et al.

Effects of self-superparasitism and host age on fitness-correlated traits in the solitary endoparasitoid wasp Meteorus pulchricornis.

PubMed

Zhang, Bo; Li, Baoping; Meng, Ling

2014-01-01

The domed fitness functions are suggested to describe developmental patterns of progeny parasitoids in relation to host age at oviposition in solitary koinobint parasitoids that are engaged in single parasitism, but few studies have investigated the applicability of the functions as related to superparasitism. The present study was designed to compare fitness functions between single parasitism and superparasitism by examining developmental patterns of Meteorus pulchricornis (Wesmael) (Hymneoptera: Braconidae) progeny in relation to the beet armyworm, Spodoptera exigua Hübner (Lepidoptera: Noctuidae), either singly parasitized or self-superparasitized as second-fifth instar larvae. Self-superparasitism caused deleterious effects on the fitness-related traits of parasitoid progeny, as demonstrated by a prolonged egg-to-adult emergence time, a smaller body size, and shorter longevity of the emerging adults, and decreased survival to adult emergence. While the domed fitness function was detected for development time, survival, adult body size, and longevity in relation to host larvae that were singly parasitized, the function was observed only for progeny survival in relation to host larvae that were self-superparasitized. This study suggests that developmental fitness functions with self-superparasitism can deviate from those with single parasitism in solitary koinobiont parasitoids.

Effects of selfsuperparasitism and host age on fitness-correlated traits in the solitary endoparasitoid wasp Meteorus pulchricornis

PubMed Central

Zhang, Bo; Li, Baoping; Meng, Ling

2014-01-01

Abstract The domed fitness functions are suggested to describe developmental patterns of progeny parasitoids in relation to host age at oviposition in solitary koinobint parasitoids that are engaged in single parasitism, but few studies have investigated the applicability of the functions as related to superparasitism. The present study was designed to compare fitness functions between single parasitism and superparasitism by examining developmental patterns of Meteorus pulchricornis (Wesmael) (Hymneoptera: Braconidae) progeny in relation to the beet armyworm, Spodoptera exigua Hübner (Lepidoptera: Noctuidae), either singly parasitized or self-superparasitized as second–fifth instar larvae. Selfsuperparasitism caused deleterious effects on the fitness-related traits of parasitoid progeny, as demonstrated by a prolonged egg-to-adult emergence time, a smaller body size, and shorter longevity of the emerging adults, and decreased survival to adult emergence. While the domed fitness function was detected for development time, survival, adult body size, and longevity in relation to host larvae that were singly parasitized, the function was observed only for progeny survival in relation to host larvae that were self-superparasitized. This study suggests that developmental fitness functions with selfsuperparasitism can deviate from those with single parasitism in solitary koinobiont parasitoids. PMID:25201512

Simulations of deep galaxy fields. 1: Monte Carlo simulations of optical and near-infrared counts

NASA Technical Reports Server (NTRS)

Chokshi, Arati; Lonsdale, Carol J.; Mazzei, Paola; De Zotti, Gianfranco

1994-01-01

Monte Carlo simulations of three-dimensional galaxy distributions are performed, following the 1988 prescription of Chokshi & Wright, to study the photometric properties of evolving galaxy populations in the optical and near-infrared bands to high redshifts. In this paper, the first of a series, we present our baseline model in which galaxy numbers are conserved, and in which no explicit 'starburst' population is included. We use the model in an attempt to simultaneously fit published blue and near-infrared photometric and spectroscopic observations of deep fields. We find that our baseline models, with a formation redshift, z(sub f), of 1000, and H(sub 0) = 50, are able to reproduce the blue counts to b(sub j) = 22, independent of the value of Omega(sub 0), and also to provide a satisfactory fit to the observed blue-band redshift distributions, but for no value of Omega(sub 0) do we achieve an acceptable fit to the fainter blue counts. In the K band, we fit the number counts to the limit of the present-day surveys only for an Omega(sub 0) = 0 cosmology. We investigate the effect on the model fits of varying the cosmological parameters H(sub 0), the formation red-shift z(sub f), and the local luminosity function. Changing H(sub 0) does not improve the fits to the observations. However, reducing the epoch of a galaxy formation used in our simulations has a substantial effect. In particular, a model with z(sub f) approximately equal to 5 in a low Omega(sub 0) universe improves the fit to the faintest photometric blue data without any need to invoke a new population of galaxies, substantial merging, or a significant starburst galaxy population. For an Omega(sub 0) = 1 universe, however, reducing z(sub f) is less successful at fitting the blue-band counts and has little effect at all at K. Varying the parameters of the local luminosity function can also have a significant effect. In particular the steep low end slope of the local luminosity function of Franceschini et al. allows an acceptable fit to the b(sub j) less than or equal to 25 counts for Omega(sub 0) = 1, but is incompatible with Omega(sub 0) = 0.

Cardiorespiratory Fitness and Cognitive Function are Positively Related Among Participants with Mild and Subjective Cognitive Impairment.

PubMed

Stuckenschneider, Tim; Askew, Christopher David; Rüdiger, Stefanie; Cristina Polidori, Maria; Abeln, Vera; Vogt, Tobias; Krome, Andreas; Olde Rikkert, Marcel; Lawlor, Brian; Schneider, Stefan

2018-01-01

By 2030, about 74 million people will be diagnosed with dementia, and many more will experience subjective (SCI) or mild cognitive impairment (MCI). As physical inactivity has been identified to be a strong modifiable risk factor for dementia, exercise and physical activity (PA) may be important parameters to predict the progression from MCI to dementia, but might also represent disease trajectory modifying strategies for SCI and MCI. A better understanding of the relationship between activity, fitness, and cognitive function across the spectrum of MCI and SCI would provide an insight into the potential utility of PA and fitness as early markers, and treatment targets to prevent cognitive decline. 121 participants were stratified into three groups, late MCI (LMCI), early MCI (EMCI), and SCI based on the Montreal Cognitive Assessment (MoCA). Cognitive function assessments also included the Trail Making Test A+B, and a verbal fluency test. PA levels were evaluated with an interviewer-administered questionnaire (LAPAQ) and an activity monitor. An incremental exercise test was performed to estimate cardiorespiratory fitness and to determine exercise capacity relative to population normative data. ANCOVA revealed that LMCI subjects had the lowest PA levels (LAPAQ, p = 0.018; activity monitor, p = 0.041), and the lowest exercise capacity in relation to normative values (p = 0.041). Moreover, a modest correlation between MoCA and cardiorespiratory fitness (r = 0.25; p < 0.05) was found. These findings suggest that during the earliest stages of cognitive impairment PA and exercise capacity might present a marker for the risk of further cognitive decline. This finding warrants further investigation using longitudinal cohort studies.

Examining the Latent Structure of the Delis-Kaplan Executive Function System.

PubMed

Karr, Justin E; Hofer, Scott M; Iverson, Grant L; Garcia-Barrera, Mauricio A

2018-05-04

The current study aimed to determine whether the Delis-Kaplan Executive Function System (D-KEFS) taps into three executive function factors (inhibition, shifting, fluency) and to assess the relationship between these factors and tests of executive-related constructs less often measured in latent variable research: reasoning, abstraction, and problem solving. Participants included 425 adults from the D-KEFS standardization sample (20-49 years old; 50.1% female; 70.1% White). Eight alternative measurement models were compared based on model fit, with test scores assigned a priori to three factors: inhibition (Color-Word Interference, Tower), shifting (Trail Making, Sorting, Design Fluency), and fluency (Verbal/Design Fluency). The Twenty Questions, Word Context, and Proverb Tests were predicted in separate structural models. The three-factor model fit the data well (CFI = 0.938; RMSEA = 0.047), although a two-factor model, with shifting and fluency merged, fit similarly well (CFI = 0.929; RMSEA = 0.048). A bifactor model fit best (CFI = 0.977; RMSEA = 0.032) and explained the most variance in shifting indicators, but rarely converged among 5,000 bootstrapped samples. When the three first-order factors simultaneously predicted the criterion variables, only shifting was uniquely predictive (p < .05; R2 = 0.246-0.408). The bifactor significantly predicted all three criterion variables (p < .001; R2 = 0.141-242). Results supported a three-factor D-KEFS model (i.e., inhibition, shifting, and fluency), although shifting and fluency were highly related (r = 0.696). The bifactor showed superior fit, but converged less often than other models. Shifting best predicted tests of reasoning, abstraction, and problem solving. These findings support the validity of D-KEFS scores for measuring executive-related constructs and provide a framework through which clinicians can interpret D-KEFS results.

On the incorporation of the geometric phase in general single potential energy surface dynamics: A removable approximation to ab initio data.

PubMed

Malbon, Christopher L; Zhu, Xiaolei; Guo, Hua; Yarkony, David R

2016-12-21

For two electronic states coupled by conical intersections, the line integral of the derivative coupling can be used to construct a complex-valued multiplicative phase factor that makes the real-valued adiabatic electronic wave function single-valued, provided that the curl of the derivative coupling is zero. Unfortunately for ab initio determined wave functions, the curl is never rigorously zero. However, when the wave functions are determined from a coupled two diabatic state Hamiltonian H d (fit to ab initio data), the resulting derivative couplings are by construction curl free, except at points of conical intersection. In this work we focus on a recently introduced diabatization scheme that produces the H d by fitting ab initio determined energies, energy gradients, and derivative couplings to the corresponding H d determined quantities in a least squares sense, producing a removable approximation to the ab initio determined derivative coupling. This approach and related numerical issues associated with the nonremovable ab initio derivative couplings are illustrated using a full 33-dimensional representation of phenol photodissociation. The use of this approach to provide a general framework for treating the molecular Aharonov Bohm effect is demonstrated.

Identification of Fitness Determinants during Energy-Limited Growth Arrest in Pseudomonas aeruginosa

PubMed Central

Basta, David W.; Bergkessel, Megan

2017-01-01

ABSTRACT Microbial growth arrest can be triggered by diverse factors, one of which is energy limitation due to scarcity of electron donors or acceptors. Genes that govern fitness during energy-limited growth arrest and the extent to which they overlap between different types of energy limitation are poorly defined. In this study, we exploited the fact that Pseudomonas aeruginosa can remain viable over several weeks when limited for organic carbon (pyruvate) as an electron donor or oxygen as an electron acceptor. ATP values were reduced under both types of limitation, yet more severely in the absence of oxygen. Using transposon-insertion sequencing (Tn-seq), we identified fitness determinants in these two energy-limited states. Multiple genes encoding general functions like transcriptional regulation and energy generation were required for fitness during carbon or oxygen limitation, yet many specific genes, and thus specific activities, differed in their relevance between these states. For instance, the global regulator RpoS was required during both types of energy limitation, while other global regulators such as DksA and LasR were required only during carbon or oxygen limitation, respectively. Similarly, certain ribosomal and tRNA modifications were specifically required during oxygen limitation. We validated fitness defects during energy limitation using independently generated mutants of genes detected in our screen. Mutants in distinct functional categories exhibited different fitness dynamics: regulatory genes generally manifested a phenotype early, whereas genes involved in cell wall metabolism were required later. Together, these results provide a new window into how P. aeruginosa survives growth arrest. PMID:29184024

Integrating evolutionary and functional approaches to infer adaptation at specific loci.

PubMed

Storz, Jay F; Wheat, Christopher W

2010-09-01

Inferences about adaptation at specific loci are often exclusively based on the static analysis of DNA sequence variation. Ideally,population-genetic evidence for positive selection serves as a stepping-off point for experimental studies to elucidate the functional significance of the putatively adaptive variation. We argue that inferences about adaptation at specific loci are best achieved by integrating the indirect, retrospective insights provided by population-genetic analyses with the more direct, mechanistic insights provided by functional experiments. Integrative studies of adaptive genetic variation may sometimes be motivated by experimental insights into molecular function, which then provide the impetus to perform population genetic tests to evaluate whether the functional variation is of adaptive significance. In other cases, studies may be initiated by genome scans of DNA variation to identify candidate loci for recent adaptation. Results of such analyses can then motivate experimental efforts to test whether the identified candidate loci do in fact contribute to functional variation in some fitness-related phenotype. Functional studies can provide corroborative evidence for positive selection at particular loci, and can potentially reveal specific molecular mechanisms of adaptation.

The Benefits of High-Intensity Functional Training Fitness Programs for Military Personnel.

PubMed

Haddock, Christopher K; Poston, Walker S C; Heinrich, Katie M; Jahnke, Sara A; Jitnarin, Nattinee

2016-11-01

High intensity functional training (HIFT) programs are designed to address multiple fitness domains, potentially providing improved physical and mental readiness in a changing operational environment. Programs consistent with HIFT principals such as CrossFit, SEALFIT and the US Marine Corps' High Intensity Tactical Training (HITT) are increasingly popular among military personnel. The goal of HIFT programs is to produce high levels of cardiorespiratory fitness, endurance and strength that exceed those achieved by following current physical activity recommendations. Given the investment in and popularity of HIFT in the military, it is important to consider the potential impact of this approach to fitness training for the health of military personnel and their risk of training injury. In a previous report in this journal, we addressed the question of whether HIFT was associated with higher injury rates compared to other exercise programs. We argued that concerns about the injury potential of HIFT exercise programs were not supported by the scientific literature to date, although additional research was needed to directly compare injury rates in approaches such as CrossFit to traditional military fitness programs. In this article we will review the scientific data on the practical, health and fitness benefits of HIFT exercise programs for military populations. Practical benefits to HIFT exercise programs include shorter training times and volumes, exercises which simulate combat tasks, lower equipment costs, reduced potential for boredom and adaptation as a result of constant variation, less injury potential compared to high volume endurance training, and scalability to all fitness levels and rehabilitation needs. For instance, HIFT training volumes are typically between 25% to nearly 80% less than traditional military fitness programs without reductions in fitness outcomes. HIFT program also provide an impressive range of health benefits such as the promotion of metabolic conditioning and muscular strength, less systemic inflammation or oxidative damage compared to sustained aerobic activity, and promoting general physical preparedness (GPP) for the unpredictable physical demands of combat. Given the unique benefits of HIFT, we recommend that these programs become the standard for military physical training. Despite the promise of HIFT fitness programs, questions remain about implementing these programs in the military context. For instance, no large scale randomized trials comparing traditional military physical training with HIFT programs on both health and injury outcomes have been conducted. Such a trial could identify key elements from both types of programs which should be incorporated in future approaches to military fitness training. Also, research regarding the optimal ways of implementing HIFT to maximize both GPP and combat oriented physical skills is lacking. It is likely that an approach to HIFT training which promotes GPP for all personnel along with specialized elements selected on the basis of individual occupation demands would be maximally disseminable in the military. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

Cuckoo Search with Lévy Flights for Weighted Bayesian Energy Functional Optimization in Global-Support Curve Data Fitting

PubMed Central

Gálvez, Akemi; Iglesias, Andrés; Cabellos, Luis

2014-01-01

The problem of data fitting is very important in many theoretical and applied fields. In this paper, we consider the problem of optimizing a weighted Bayesian energy functional for data fitting by using global-support approximating curves. By global-support curves we mean curves expressed as a linear combination of basis functions whose support is the whole domain of the problem, as opposed to other common approaches in CAD/CAM and computer graphics driven by piecewise functions (such as B-splines and NURBS) that provide local control of the shape of the curve. Our method applies a powerful nature-inspired metaheuristic algorithm called cuckoo search, introduced recently to solve optimization problems. A major advantage of this method is its simplicity: cuckoo search requires only two parameters, many fewer than other metaheuristic approaches, so the parameter tuning becomes a very simple task. The paper shows that this new approach can be successfully used to solve our optimization problem. To check the performance of our approach, it has been applied to five illustrative examples of different types, including open and closed 2D and 3D curves that exhibit challenging features, such as cusps and self-intersections. Our results show that the method performs pretty well, being able to solve our minimization problem in an astonishingly straightforward way. PMID:24977175

Cuckoo search with Lévy flights for weighted Bayesian energy functional optimization in global-support curve data fitting.

PubMed

Gálvez, Akemi; Iglesias, Andrés; Cabellos, Luis

2014-01-01

The problem of data fitting is very important in many theoretical and applied fields. In this paper, we consider the problem of optimizing a weighted Bayesian energy functional for data fitting by using global-support approximating curves. By global-support curves we mean curves expressed as a linear combination of basis functions whose support is the whole domain of the problem, as opposed to other common approaches in CAD/CAM and computer graphics driven by piecewise functions (such as B-splines and NURBS) that provide local control of the shape of the curve. Our method applies a powerful nature-inspired metaheuristic algorithm called cuckoo search, introduced recently to solve optimization problems. A major advantage of this method is its simplicity: cuckoo search requires only two parameters, many fewer than other metaheuristic approaches, so the parameter tuning becomes a very simple task. The paper shows that this new approach can be successfully used to solve our optimization problem. To check the performance of our approach, it has been applied to five illustrative examples of different types, including open and closed 2D and 3D curves that exhibit challenging features, such as cusps and self-intersections. Our results show that the method performs pretty well, being able to solve our minimization problem in an astonishingly straightforward way.

Practical training framework for fitting a function and its derivatives.

PubMed

Pukrittayakamee, Arjpolson; Hagan, Martin; Raff, Lionel; Bukkapatnam, Satish T S; Komanduri, Ranga

2011-06-01

This paper describes a practical framework for using multilayer feedforward neural networks to simultaneously fit both a function and its first derivatives. This framework involves two steps. The first step is to train the network to optimize a performance index, which includes both the error in fitting the function and the error in fitting the derivatives. The second step is to prune the network by removing neurons that cause overfitting and then to retrain it. This paper describes two novel types of overfitting that are only observed when simultaneously fitting both a function and its first derivatives. A new pruning algorithm is proposed to eliminate these types of overfitting. Experimental results show that the pruning algorithm successfully eliminates the overfitting and produces the smoothest responses and the best generalization among all the training algorithms that we have tested.

Influence of fitness and age on the endothelial response to acute inflammation.

PubMed

Schroeder, Elizabeth C; Lane-Cordova, Abbi D; Ranadive, Sushant M; Baynard, Tracy; Fernhall, Bo

2018-06-01

What is the central question of the study? What are the effects of age and fitness on the vascular response to acute inflammation in younger and older adults? What is the main finding and its importance? In older adults, cardiorespiratory fitness level has a differential impact on endothelial function after acute inflammation. Compared with older adults with low fitness, older, moderately fit adults have a greater decrease in endothelial function, similar to that of younger adults. These findings have important implications in support of the beneficial effects of higher cardiorespiratory fitness in maintaining vascular reactivity and the ability to respond to stressors. Inflammation is associated with greater risk of cardiovascular events and reduced vascular function with ageing. Higher cardiorespiratory fitness is associated with lower risk of cardiovascular events and better vascular function. We evaluated the role of fitness in the vascular response to acute inflammation in 26 younger adults (YA) and 62 older adults (OA). We used an influenza vaccine to induce acute inflammation. Blood pressure, flow-mediated dilatation (FMD), augmentation index, carotid elastic modulus and inflammatory markers were measured before and 24 h after vaccination. Peak oxygen uptake was measured via a treadmill test. 'Fit' was defined as a peak oxygen uptake greater than the age- and sex-determined 50th percentile according to the American College of Sports Medicine. An interaction effect existed for the FMD response during acute inflammation (P < 0.05). The YA (low fit, from 11.5 ± 1.8 to 9.2 ± 1.3%; moderately fit, from 11.9 ± 0.8 to 9.0 ± 0.8%) and moderately fit OA (from 7.5 ± 1.0 to 3.9 ± 0.8%) had similar reductions in FMD at 24 h (P < 0.05). Low-fit OA did not reduce FMD at 24 h (from 5.5 ± 0.4 to 5.2 ± 0.5%, P > 0.05). The reduction in FMD in YA was similar between fitness groups (P > 0.05). All groups had similar reductions in mean arterial pressure and increases in inflammatory markers. The augmentation index and carotid elastic modulus did not change during acute inflammation. In conclusion, in OA, higher fitness is associated with a greater decrease in endothelial function during acute inflammation, and this response is similar to that of young adults. This suggests that moderately fit OA may maintain vascular reactivity in response to stress, indicating preserved vascular function in moderately fit versus low-fit OA. © 2018 The Authors. Experimental Physiology © 2018 The Physiological Society.

Efficient Evaluation Functions for Multi-Rover Systems

NASA Technical Reports Server (NTRS)

Agogino, Adrian; Tumer, Kagan

2004-01-01

Evolutionary computation can be a powerful tool in cresting a control policy for a single agent receiving local continuous input. This paper extends single-agent evolutionary computation to multi-agent systems, where a collection of agents strives to maximize a global fitness evaluation function that rates the performance of the entire system. This problem is solved in a distributed manner, where each agent evolves its own population of neural networks that are used as the control policies for the agent. Each agent evolves its population using its own agent-specific fitness evaluation function. We propose to create these agent-specific evaluation functions using the theory of collectives to avoid the coordination problem where each agent evolves a population that maximizes its own fitness function, yet the system has a whole achieves low values of the global fitness function. Instead we will ensure that each fitness evaluation function is both "aligned" with the global evaluation function and is "learnable," i.e., the agents can readily see how their behavior affects their evaluation function. We then show how these agent-specific evaluation functions outperform global evaluation methods by up to 600% in a domain where a set of rovers attempt to maximize the amount of information observed while navigating through a simulated environment.

Postgraduate Transnational Education in Nonbusiness Subjects: Can It Fit Conceptualizations of Curriculum Internationalization?

ERIC Educational Resources Information Center

Chan, Benjamin Tak-Yuen

2011-01-01

The issue of teaching and learning in transnational education has increasingly received attention through studies about "curriculum internationalization." To date, many of the examples and theorizations about curriculum internationalization are provided by business courses. This is largely a function of trade and commercial activities being…

Exercise Prescriptions for Active Seniors: A Team Approach for Maximizing Adherence.

ERIC Educational Resources Information Center

Brennan, Fred H., Jr.

2002-01-01

Exercise is an important "medication" that healthcare providers can prescribe for their geriatric patients. Increasing physical fitness by participating in regular exercise can reduce the effects of aging that lead to functional declines and poor health. Modest regular exercise can substantially lower the risk of death from coronary…

Some Properties of Estimated Scale Invariant Covariance Structures.

ERIC Educational Resources Information Center

Dijkstra, T. K.

1990-01-01

An example of scale invariance is provided via the LISREL model that is subject only to classical normalizations and zero constraints on the parameters. Scale invariance implies that the estimated covariance matrix must satisfy certain equations, and the nature of these equations depends on the fitting function used. (TJH)

The benefits of Tai Chi and brisk walking for cognitive function and fitness in older adults

PubMed Central

Ji, Zhiguang; Feng, Tian; Liu, Xiaolei; You, Yihong; Meng, Fanying; Wang, Ruoqing; Lu, Jialing

2017-01-01

The purpose of this study was to investigate the benefits of exercises with different cognitive demands for cognitive functions (Executive and non-Executive) in healthy older adults. A cross-sectional design was adopted. In total, 84 healthy older adults were enrolled in the study. They were categorized into the Tai Chi group (TG), the brisk walking group (BG) or the control group (CG). Each participant performed the Stroop task and a digit comparison task. The Stroop task included the following three conditions: a naming condition, an inhibition condition and an executive condition. There were two experimental conditions in the digit comparison task: the non-delay condition and the delay condition. The results indicated that participants of the TG and BG revealed significant better performance than the CG in the executive condition of cognitive tasks and fitness. There was no significant difference of reaction time (RT) and accuracy rate in the inhibition and delay conditions of cognitive tasks and fitness between the TG and BG. The TG showed shorter reaction time in the naming and the executive conditions, and more accurate in the inhibition conditions than the BG. These findings demonstrated that regular participation in brisk walking and Tai Chi have significant beneficial effects on executive function and fitness. However, due to the high cognitive demands of the exercise, Tai Chi benefit cognitive functions (Executive and non-Executive) in older adults more than brisk walking does. Further studies should research the underlying mechanisms at the behavioural and neuroelectric levels, providing more evidence to explain the effect of high-cognitive demands exercise on different processing levels of cognition. PMID:29062610

Effective charges of ionic liquid determined self-consistently through combination of molecular dynamics simulation and density-functional theory.

PubMed

Ishizuka, Ryosuke; Matubayasi, Nobuyuki

2017-11-15

A self-consistent scheme combining the molecular dynamics (MD) simulation and density functional theory (DFT) was recently proposed to incorporate the effects of the charge transfer and polarization of ions into non-poralizable force fields of ionic liquids for improved description of energetics and dynamics. The purpose of the present work is to analyze the detailed setups of the MD/DFT scheme by focusing on how the basis set, exchange-correlation (XC) functional, charge-fitting method or force field for the intramolecular and Lennard-Jones interactions affects the MD/DFT results of 1,3-dimethylimidazolium bis(trifluoromethylsulfonyl) imide ( [C1mim][NTf2]) and 1-ethyl-3-methylimidazolium glycinate ( [C2mim][Gly]). It was found that the double-zeta valence polarized or larger size of basis set is required for the convergence of the effective charge of the ion. The choice of the XC functional was further not influential as far as the generalized gradient approximation is used. The charge-fitting method and force field govern the accuracy of the MD/DFT scheme, on the other hand. We examined the charge-fitting methods of Blöchl, the iterative Hirshfeld (Hirshfeld-I), and REPEAT in combination with Lopes et al.'s force field and general AMBER force field. There is no single combination of charge fitting and force field that provides good agreements with the experiments, while the MD/DFT scheme reduces the effective charges of the ions and leads to better description of energetics and dynamics compared to the original force field with unit charges. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Editorial Commentary: Polyurethane Meniscal Scaffold: A Perfect Fit or Flop?

PubMed

Barber, F Alan

2018-05-01

The goal of using a synthetic scaffold to establish a biomechanically functioning meniscus or provide an equivalent meniscus substitute is not achieved by the polycaprolactone-polyurethane Actifit scaffold. Recent research, that did not include a control group, shows that the revision rate is significant, and any improvements in patient outcomes could reflect the associated reconstructive surgery. Based on these data and similar published reports, it is premature to conclude that this implant is clinically indicated. The technique is currently more flop than fit. Copyright © 2018 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

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.

Fitness Probability Distribution of Bit-Flip Mutation.

PubMed

Chicano, Francisco; Sutton, Andrew M; Whitley, L Darrell; Alba, Enrique

2015-01-01

Bit-flip mutation is a common mutation operator for evolutionary algorithms applied to optimize functions over binary strings. In this paper, we develop results from the theory of landscapes and Krawtchouk polynomials to exactly compute the probability distribution of fitness values of a binary string undergoing uniform bit-flip mutation. We prove that this probability distribution can be expressed as a polynomial in p, the probability of flipping each bit. We analyze these polynomials and provide closed-form expressions for an easy linear problem (Onemax), and an NP-hard problem, MAX-SAT. We also discuss a connection of the results with runtime analysis.

Properties of {sup 112}Cd from the (n,n'{gamma}) reaction: Levels and level densities

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

Garrett, P. E.; Lehmann, H.; Jolie, J.

2001-08-01

Levels in {sup 112}Cd have been studied through the (n,n'{gamma}) reaction with monoenergetic neutrons. An extended set of experiments that included excitation functions, {gamma}-ray angular distributions, and {gamma}{gamma} coincidence measurements was performed. A total of 375 {gamma} rays were placed in a level scheme comprising 200 levels (of which 238 {gamma}-ray assignments and 58 levels are newly established) up to 4 MeV in excitation. No evidence to support the existence of 47 levels as suggested in previous studies was found, and these have been removed from the level scheme. From the results, a comparison of the level density is mademore » with the constant temperature and back-shifted Fermi gas models. The back-shifted Fermi gas model with the Gilbert-Cameron spin cutoff parameter provided the best overall fit. Without using the neutron resonance information and only fitting the cumulative number of low-lying levels, the level density parameters extracted are a sensitive function of the maximum energy used in the fit.« less

Fast local-MP2 method with density-fitting for crystals. II. Test calculations and application to the carbon dioxide crystal

NASA Astrophysics Data System (ADS)

Usvyat, Denis; Maschio, Lorenzo; Manby, Frederick R.; Casassa, Silvia; Schütz, Martin; Pisani, Cesare

2007-08-01

A density fitting scheme for calculating electron repulsion integrals used in local second order Møller-Plesset perturbation theory for periodic systems (DFP) is presented. Reciprocal space techniques are systematically adopted, for which the use of Poisson fitting functions turned out to be instrumental. The role of the various parameters (truncation thresholds, density of the k net, Coulomb versus overlap metric, etc.) on computational times and accuracy is explored, using as test cases primitive-cell- and conventional-cell-diamond, proton-ordered ice, crystalline carbon dioxide, and a three-layer slab of magnesium oxide. Timings and results obtained when the electron repulsion integrals are calculated without invoking the DFP approximation, are taken as the reference. It is shown that our DFP scheme is both accurate and very efficient once properly calibrated. The lattice constant and cohesion energy of the CO2 crystal are computed to illustrate the capabilities of providing a physically correct description also for weakly bound crystals, in strong contrast to present density functional approaches.

The Relationship of Physiopsychosocial Factors and Spiritual Well-Being in Elderly Residents: Implications for Evidence-Based Practice.

PubMed

Chen, Yi-Heng; Lin, Li-Chan; Chuang, Li-Lan; Chen, Mei-Li

2017-12-01

Older adults in residential settings frequently suffer from functional decline, mental illness, and social isolation, which make them more vulnerable to spiritual distress. However, empirical evidence of the interrelationships between physiopsychosocial variables and spiritual well-being are still lacking, limiting the application of the biopsychosocial-spiritual model in institutional healthcare practice. To explain the mechanisms by which these variables are linked, this cross-sectional study tested a causal model of predictors of spiritual well-being among 377 institutionalized older adults with disability using a structural equation modeling approach. The primary variables in the hypothesized model were measured using the Barthel Index for functional ability, the Geriatric Depression Scale-short form for depression, the Personal Resources Questionnaire 85-Part 2 for perceived social support, and the Spiritual Well-Being Scale for spiritual well-being. The model fit indices suggest that the hypothesized model had a reasonably adequate model fit (χ 2 = 12.18, df = 6, p = .07, goodness-of-fitness index [GFI] = 0.99, adjusted GIF index [AGFI] = 0.93, nonnormed fit index [NFI] = 0.99, comparative fit index [CFI] = 0.99). In this study, perceived social support and depression directly affected spiritual well-being, and functional ability indirectly affected spiritual well-being via perceived social support or depression. In addition, functional ability influenced perceived social support directly, which in turn influenced depression and ultimately influenced spiritual well-being. This study results confirm the effect of physiopsychosocial factors on institutionalized older adults' spiritual well-being. However, the presence and level of functional disability do not necessarily influence spiritual well-being in late life unless it is disruptive to social relationships and is thus bound to lead to low perceived social support and the onset of depression. The findings address the fact that the practice of spirituality is multidimensional and multileveled. Psychosocial interventions for institutionalized elders with disabilities should focus on increasing nurse-patient interaction and providing access to meaningful social activities to improve mental health and spiritual well-being. © 2017 Sigma Theta Tau International.

Verification of a VRF Heat Pump Computer Model in EnergyPlus

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

Nigusse, Bereket; Raustad, Richard

2013-06-15

This paper provides verification results of the EnergyPlus variable refrigerant flow (VRF) heat pump computer model using manufacturer's performance data. The paper provides an overview of the VRF model, presents the verification methodology, and discusses the results. The verification provides quantitative comparison of full and part-load performance to manufacturer's data in cooling-only and heating-only modes of operation. The VRF heat pump computer model uses dual range bi-quadratic performance curves to represent capacity and Energy Input Ratio (EIR) as a function of indoor and outdoor air temperatures, and dual range quadratic performance curves as a function of part-load-ratio for modeling part-loadmore » performance. These performance curves are generated directly from manufacturer's published performance data. The verification compared the simulation output directly to manufacturer's performance data, and found that the dual range equation fit VRF heat pump computer model predicts the manufacturer's performance data very well over a wide range of indoor and outdoor temperatures and part-load conditions. The predicted capacity and electric power deviations are comparbale to equation-fit HVAC computer models commonly used for packaged and split unitary HVAC equipment.« less

Failure statistics for commercial lithium ion batteries: A study of 24 pouch cells

NASA Astrophysics Data System (ADS)

Harris, Stephen J.; Harris, David J.; Li, Chen

2017-02-01

There are relatively few publications that assess capacity decline in enough commercial cells to quantify cell-to-cell variation, but those that do show a surprisingly wide variability. Capacity curves cross each other often, a challenge for efforts to measure the state of health and predict the remaining useful life (RUL) of individual cells. We analyze capacity fade statistics for 24 commercial pouch cells, providing an estimate for the time to 5% failure. Our data indicate that RUL predictions based on remaining capacity or internal resistance are accurate only once the cells have already sorted themselves into "better" and "worse" ones. Analysis of our failure data, using maximum likelihood techniques, provide uniformly good fits for a variety of definitions of failure with normal and with 2- and 3-parameter Weibull probability density functions, but we argue against using a 3-parameter Weibull function for our data. pdf fitting parameters appear to converge after about 15 failures, although business objectives should ultimately determine whether data from a given number of batteries provides sufficient confidence to end lifecycle testing. Increased efforts to make batteries with more consistent lifetimes should lead to improvements in battery cost and safety.

Incest versus abstinence: reproductive trade-offs between mate limitation and progeny fitness in a self-incompatible invasive plant

PubMed Central

Pierson, Jennifer C; Swain, Stephen M; Young, Andrew G

2013-01-01

Plant mating systems represent an evolutionary and ecological trade-off between reproductive assurance through selfing and maximizing progeny fitness through outbreeding. However, many plants with sporophytic self-incompatibility systems exhibit dominance interactions at the S-locus that allow biparental inbreeding, thereby facilitating mating between individuals that share alleles at the S-locus. We investigated this trade-off by estimating mate availability and biparental inbreeding depression in wild radish from five different populations across Australia. We found dominance interactions among S-alleles increased mate availability relative to estimates based on individuals that did not share S-alleles. Twelve of the sixteen fitness variables were significantly reduced by inbreeding. For all the three life-history phases evaluated, self-fertilized offspring suffered a greater than 50% reduction in fitness, while full-sib and half-sib offspring suffered a less than 50% reduction in fitness. Theory indicates that fitness costs greater than 50% can result in an evolutionary trajectory toward a stable state of self-incompatibility (SI). This study suggests that dominance interactions at the S-locus provide a possible third stable state between SI and SC where biparental inbreeding increases mate availability with relatively minor fitness costs. This strategy allows weeds to establish in new environments while maintaining a functional SI system. PMID:24455137

Incest versus abstinence: reproductive trade-offs between mate limitation and progeny fitness in a self-incompatible invasive plant.

PubMed

Pierson, Jennifer C; Swain, Stephen M; Young, Andrew G

2013-12-01

Plant mating systems represent an evolutionary and ecological trade-off between reproductive assurance through selfing and maximizing progeny fitness through outbreeding. However, many plants with sporophytic self-incompatibility systems exhibit dominance interactions at the S-locus that allow biparental inbreeding, thereby facilitating mating between individuals that share alleles at the S-locus. We investigated this trade-off by estimating mate availability and biparental inbreeding depression in wild radish from five different populations across Australia. We found dominance interactions among S-alleles increased mate availability relative to estimates based on individuals that did not share S-alleles. Twelve of the sixteen fitness variables were significantly reduced by inbreeding. For all the three life-history phases evaluated, self-fertilized offspring suffered a greater than 50% reduction in fitness, while full-sib and half-sib offspring suffered a less than 50% reduction in fitness. Theory indicates that fitness costs greater than 50% can result in an evolutionary trajectory toward a stable state of self-incompatibility (SI). This study suggests that dominance interactions at the S-locus provide a possible third stable state between SI and SC where biparental inbreeding increases mate availability with relatively minor fitness costs. This strategy allows weeds to establish in new environments while maintaining a functional SI system.

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

An Efficient Implementation of Fixed Failure-Rate Ratio Test for GNSS Ambiguity Resolution.

PubMed

Hou, Yanqing; Verhagen, Sandra; Wu, Jie

2016-06-23

Ambiguity Resolution (AR) plays a vital role in precise GNSS positioning. Correctly-fixed integer ambiguities can significantly improve the positioning solution, while incorrectly-fixed integer ambiguities can bring large positioning errors and, therefore, should be avoided. The ratio test is an extensively used test to validate the fixed integer ambiguities. To choose proper critical values of the ratio test, the Fixed Failure-rate Ratio Test (FFRT) has been proposed, which generates critical values according to user-defined tolerable failure rates. This contribution provides easy-to-implement fitting functions to calculate the critical values. With a massive Monte Carlo simulation, the functions for many different tolerable failure rates are provided, which enriches the choices of critical values for users. Moreover, the fitting functions for the fix rate are also provided, which for the first time allows users to evaluate the conditional success rate, i.e., the success rate once the integer candidates are accepted by FFRT. The superiority of FFRT over the traditional ratio test regarding controlling the failure rate and preventing unnecessary false alarms is shown by a simulation and a real data experiment. In the real data experiment with a baseline of 182.7 km, FFRT achieved much higher fix rates (up to 30% higher) and the same level of positioning accuracy from fixed solutions as compared to the traditional critical value.

Acute effects of moderate aerobic exercise on specific aspects of executive function in different age and fitness groups: A meta-analysis.

PubMed

Ludyga, Sebastian; Gerber, Markus; Brand, Serge; Holsboer-Trachsler, Edith; Pühse, Uwe

2016-11-01

Whereas a wealth of studies have investigated acute effects of moderate aerobic exercise on executive function, the roles of age, fitness, and the component of executive function in this relationship still remain unclear. Therefore, the present meta-analysis investigates exercise-induced benefits on specific aspects of executive function in different age and aerobic fitness subgroups. Based on data from 40 experimental studies, a small effect of aerobic exercise on time-dependent measures (g = .35) and accuracy (g = .22) in executive function tasks was confirmed. The results further suggest that preadolescent children (g = .54) and older adults (g = .67) compared to other age groups benefit more from aerobic exercise when reaction time is considered as dependent variable. In contrast to age, aerobic fitness and the executive function component had no influence on the obtained effect sizes. Consequently, high aerobic fitness is no prerequisite for temporary improvements of the executive control system, and low- as well as high-fit individuals seem to benefit from exercise in a similar way. However, a higher sensitivity of executive function to acute aerobic exercise was found in individuals undergoing developmental changes. Therefore, preadolescent children and older adults in particular might strategically use a single aerobic exercise session to prepare for a situation demanding high executive control. © 2016 Society for Psychophysiological Research.

Incorporating Family Function into Chronic Pain Disability: The Role of Catastrophizing

PubMed Central

Akbari, Fatemeh; Dehghani, Mohsen; Khatibi, Ali; Vervoort, Tine

2016-01-01

Background. Observers' responses to pain are recently investigated to more comprehensively explain chronic pain (CP) and disability. However, the role of family context, defined as interference in roles, communication, and problem-solving, and how (i.e., through which mechanisms) these variables contribute to CP related disability have yet to be examined. Objectives. The aim of the present study is to examine family context in relationship to pain catastrophizing, fear of movement, and depression and its role in understanding CP disability. Three different models were examined. Methods. A total sample of 142 patients with musculoskeletal chronic pain was recruited to examine the role of fear of movement, pain intensity, pain catastrophizing, and depression in relationship to family functioning as predictors of disability. Results. Findings indicated that two models showed acceptable fit, but one of them revealed superior fit indices. Results of the model with superior fit indices indicated that family dysfunction may contribute to catastrophic thinking, which, in turn, contributes to patients' disability through increasing fear of movement and depression. Discussion. The current study provides further support for the notion that the impact of emotional and cognitive variables upon CP-related disability can be better understood when we consider the social context of pain patients and family function in particular. PMID:27445620

Wii-based Balance Therapy to Improve Balance Function of Children with Cerebral Palsy: A Pilot Study

PubMed Central

Tarakci, Devrim; Ozdincler, Arzu Razak; Tarakci, Ela; Tutuncuoglu, Fatih; Ozmen, Meral

2013-01-01

[Purpose] Cerebral palsy is a sensorimotor disorder that affects the control of posture and movement. The Nintendo® Wii Fit offers an inexpensive, enjoyable, suitable alternative to more complex systems for children with cerebral palsy. The aim of this study was to investigate the efficacacy of Wii-based balance therapy for children with ambulatory cerebral palsy. [Subjects] This pilot study design included fourteen ambulatory patients with cerebral palsy (11 males, 3 females; mean age 12.07 ± 3.36 years). [Methods] Balance functions before and after treatment were evaluated using one leg standing, the functional reach test, the timed up and go test, and the 6-minute walking test. The physiotherapist prescribed the Wii Fit activities,and supervised and supported the patients during the therapy sessions. Exercises were performed in a standardized program 2 times a week for 12 weeks. [Results] Balance ability of every patient improved. Statistically significant improvements were found in all outcome measures after 12 weeks. [Conclusion] The results suggest that the Nintendo® Wii Fit provides a safe, enjoyable, suitable and effective method that can be added to conventional treatments to improve the static balance of patients with cerebral palsy; however, further work is required. PMID:24259928

Incorporating Family Function into Chronic Pain Disability: The Role of Catastrophizing.

PubMed

Akbari, Fatemeh; Dehghani, Mohsen; Khatibi, Ali; Vervoort, Tine

2016-01-01

Background. Observers' responses to pain are recently investigated to more comprehensively explain chronic pain (CP) and disability. However, the role of family context, defined as interference in roles, communication, and problem-solving, and how (i.e., through which mechanisms) these variables contribute to CP related disability have yet to be examined. Objectives. The aim of the present study is to examine family context in relationship to pain catastrophizing, fear of movement, and depression and its role in understanding CP disability. Three different models were examined. Methods. A total sample of 142 patients with musculoskeletal chronic pain was recruited to examine the role of fear of movement, pain intensity, pain catastrophizing, and depression in relationship to family functioning as predictors of disability. Results. Findings indicated that two models showed acceptable fit, but one of them revealed superior fit indices. Results of the model with superior fit indices indicated that family dysfunction may contribute to catastrophic thinking, which, in turn, contributes to patients' disability through increasing fear of movement and depression. Discussion. The current study provides further support for the notion that the impact of emotional and cognitive variables upon CP-related disability can be better understood when we consider the social context of pain patients and family function in particular.

[Institutionalized elderly: functional capacity and physical fitness].

PubMed

Gonçalves, Lúcia Hisako Takase; Silva, Aline Huber da; Mazo, Giovana Zarpsellon; Benedetti, Tânia R Bertoldo; dos Santos, Silvia Maria Azevedo; Marques, Sueli; Rodrigues, Rosalina A Partezani; Portella, Marilene Rodrigues; Scortegagna, Helenice de Moura; Santos, Silvana Sidney C; Pelzer, Marlene Teda; Souza, Andrea dos Santos; Meira, Edmeia Campos; Sena, Edite Lago da Silva; Creutzberg, Marion; Resende, Thais de Lima; Rezende, Tais de Lima

2010-09-01

This study analyzed the relationship between physical fitness and functional capacity in 78 residents of long-stay institutions for low-income elderly located in five regions of Brazil. The majority of the sample consisted of women, and mean age was 77.4 years (SD = 7.9). Physical fitness was assessed with the AAHPERD test, adjusted for institutionalized elderly. The Katz scale was used for functional capacity. The five components of physical fitness rated fair for flexibility, coordination, agility, and aerobic endurance and good for strength. The mean general physical fitness (GPF) index was fair. According to the findings, the greater the degree of dependency in institutionalized elderly, the lesser their strength and GPF level; meanwhile, better coordination and agility are associated with greater independence for performing activities of daily living. The results can contribute to appropriate physical exercise programs for maintenance and/or recovery of functionality.

Radiographic parameters improve lower extremity prosthetic alignment.

PubMed

Mooney, Ryan; Carry, Patrick; Wylie, Erin; Schultz, Abby; McNair, Bryan; Page, Carol; Biffl, Susan; Heare, Travis

2013-12-01

The goal of prosthetic fitting is to provide comfort and functionality to the patient. It is thought that incorporating the use of standing anterior-posterior long leg radiographs (LLR) into the fitting of lower extremity prostheses will provide an objective guide when making adjustments, and be a better assessment of alignment. This study compares prosthetic alignment before and after radiography-guided adjustments. This retrospective study was performed at a multidisciplinary amputee clinic on patients with congenital and/or acquired limb deficiencies. Their prosthetic alignment was evaluated by LLR and adjusted as needed. Satisfactory alignment was defined as a mechanical axis angular deviation of ≤1° and a leg length discrepancy of ≤10 mm. A total of 45 unique prostheses from 24 subjects (10 female and 14 male) were included. Post-adjustment radiographs were obtained from 29 prostheses. After the initial prosthetic fitting, the probability of a satisfactory fit was 20.0 % (95 % CI 10.9-34.9 %). Following the baseline adjustment, the probability of a satisfactory fit improved to 53.3 % (95 % CI 37.5-70.9 %). After adjustment number 4, the probability of a satisfactory fit further improved to 76.7 % (95 % CI 41.9-98.0 %). There were also significant improvements in distal offset distance (p = 0.0040) and leg length discrepancy (p = 0.0206). The distal offset distance decreased by an average of 10.7 mm (95 % CI 3.6-17.8), and leg length discrepancy decreased by an average of 3.0 mm (95 % CI 00.48-5.5). The addition of LLRs to existing fitting methods significantly improves prosthetic alignment and length.

Maximum-likelihood curve-fitting scheme for experiments with pulsed lasers subject to intensity fluctuations.

PubMed

Metz, Thomas; Walewski, Joachim; Kaminski, Clemens F

2003-03-20

Evaluation schemes, e.g., least-squares fitting, are not generally applicable to any types of experiments. If the evaluation schemes were not derived from a measurement model that properly described the experiment to be evaluated, poorer precision or accuracy than attainable from the measured data could result. We outline ways in which statistical data evaluation schemes should be derived for all types of experiment, and we demonstrate them for laser-spectroscopic experiments, in which pulse-to-pulse fluctuations of the laser power cause correlated variations of laser intensity and generated signal intensity. The method of maximum likelihood is demonstrated in the derivation of an appropriate fitting scheme for this type of experiment. Statistical data evaluation contains the following steps. First, one has to provide a measurement model that considers statistical variation of all enclosed variables. Second, an evaluation scheme applicable to this particular model has to be derived or provided. Third, the scheme has to be characterized in terms of accuracy and precision. A criterion for accepting an evaluation scheme is that it have accuracy and precision as close as possible to the theoretical limit. The fitting scheme derived for experiments with pulsed lasers is compared to well-established schemes in terms of fitting power and rational functions. The precision is found to be as much as three timesbetter than for simple least-squares fitting. Our scheme also suppresses the bias on the estimated model parameters that other methods may exhibit if they are applied in an uncritical fashion. We focus on experiments in nonlinear spectroscopy, but the fitting scheme derived is applicable in many scientific disciplines.

Adherence to physical activity guidelines and functional fitness of elderly women, using objective measurement.

PubMed

Nawrocka, Agnieszka; Mynarski, Władysław; Cholewa, Jarosław

2017-12-23

Physical activity is an important factor in maintaining the health and functional fitness of elderly people. The aim of the study was to determine the number of senior women meeting the physical activity guidelines, and their level of functional fitness in comparison to women who are not sufficiently physically active. The study involved 61 women, aged 60-75. Physical activity was monitored on seven consecutive days of the week, using a triaxial accelerometer ActiGraph GT3X. Results of the assessment of physical activity were verified against the Global Recommendations of Physical Activity for Health. The Senior Fitness Test (Fullerton Test) was used to evaluate functional fitness. In the studied group, 36.1% achieved the recommended level of physical activity. All those examined mainly undertook physical activity of low intensity. Vigorous physical activity during the week was noted in only 6 seniors. Women who met the recommendations of physical activity achieved significantly better results in test trials, e.g. Chair Stands, Up and Go, Six Minute Step Test. Adherence to physical activity guidelines was associated with better functional fitness of older women. However, less than half of the examined seniors met the Global Recommendations on Physical Activity for Health.

Photovoltaics: Reviewing the European Feed-in-Tariffs and Changing PV Efficiencies and Costs

PubMed Central

Zhang, H. L.; Van Gerven, T.; Baeyens, J.; Degrève, J.

2014-01-01

Feed-in-Tariff (FiT) mechanisms have been important in boosting renewable energy, by providing a long-term guaranteed subsidy of the kWh-price, thus mitigating investment risks and enhancing the contribution of sustainable electricity. By ongoing PV development, the contribution of solar power increases exponentially. Within this significant potential, it is important for investors, operators, and scientists alike to provide answers to different questions related to subsidies, PV efficiencies and costs. The present paper therefore (i) briefly reviews the mechanisms, advantages, and evolution of FiT; (ii) describes the developments of PV, (iii) applies a comprehensive literature-based model for the solar irradiation to predict the PV solar energy potential in some target European countries, whilst comparing output predictions with the monthly measured electricity generation of a 57 m² photovoltaic system (Belgium); and finally (iv) predicts the levelized cost of energy (LCOE) in terms of investment and efficiency, providing LCOE values between 0.149 and 0.313 €/kWh, as function of the overall process efficiency and cost. The findings clearly demonstrate the potential of PV energy in Europe, where FiT can be considerably reduced or even be eliminated in the near future. PMID:24959614

Single-wavelength based Thai jasmine rice identification with polynomial fitting function and neural network analysis

NASA Astrophysics Data System (ADS)

Suwansukho, Kajpanya; Sumriddetchkajorn, Sarun; Buranasiri, Prathan

2013-06-01

We previously showed that a combination of image thresholding, chain coding, elliptic Fourier descriptors, and artificial neural network analysis provided a low false acceptance rate (FAR) and a false rejection rate (FRR) of 11.0% and 19.0%, respectively, in identify Thai jasmine rice from three unwanted rice varieties. In this work, we highlight that only a polynomial function fitting on the determined chain code and the neural network analysis are highly sufficient in obtaining a very low FAR of < 3.0% and a very low 0.3% FRR for the separation of Thai jasmine rice from Chainat 1 (CNT1), Prathumtani 1 (PTT1), and Hom-Pitsanulok (HPSL) rice varieties. With this proposed approach, the analytical time is tremendously suppressed from 4,250 seconds down to 2 seconds, implying extremely high potential in practical deployment.

Motion-oriented 3D analysis of body measurements

NASA Astrophysics Data System (ADS)

Loercher, C.; Morlock, S.; Schenk, A.

2017-10-01

The aim of this project is to develop an ergonomically based and motion-oriented size system. New concepts are required in order to be able to deal competently with complex requirements of function-oriented workwear and personal protective equipment (PPE). Body dimensions change through movement, which are basis for motion optimized clothing development. This affects fit and ergonomic comfort. The situation has to be fundamentally researched in order to derive well-founded anthropometric body data, taking into account kinematic requirements of humans and to define functional dimensions for clothing industry. Research focus shall be on ergonomic design of workwear and PPE. There are huge differences in body forms, proportions and muscle manifestations between genders. An improved basic knowledge can be provided as a result, supporting development as well as sales of motion-oriented clothing with perfect fit for garment manufacturers.

First Monte Carlo analysis of fragmentation functions from single-inclusive e + e - annihilation

DOE PAGES

Sato, Nobuo; Ethier, J. J.; Melnitchouk, W.; ...

2016-12-02

Here, we perform the first iterative Monte Carlo (IMC) analysis of fragmentation functions constrained by all available data from single-inclusive $e^+ e^-$ annihilation into pions and kaons. The IMC method eliminates potential bias in traditional analyses based on single fits introduced by fixing parameters not well contrained by the data, and provides a statistically rigorous determination of uncertainties. Our analysis reveals specific features of fragmentation functions using the new IMC methodology and those obtained from previous analyses, especially for light quarks and for strange quark fragmentation to kaons.

Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

DOE PAGES

Overton, K. Wesley; Park, Dan M.; Yung, Mimi C.; ...

2016-09-23

Surface layers, or S-layers, are two-dimensional protein arrays that form the outermost layer of many bacteria and archaea. They serve several functions, including physical protection of the cell from environmental threats. The high abundance of S-layer proteins necessitates a highly efficient export mechanism to transport the S-layer protein from the cytoplasm to the cell exterior.Caulobacter crescentusis unique in that it has two homologous, seemingly redundant outer membrane proteins, RsaF aand RsaF b, which together with other components form a type I protein translocation pathway for S-layer export. These proteins have homology toEscherichia coliTolC, the outer membrane channel of multidrug effluxmore » pumps. Here we provide evidence that, unlike TolC, RsaF aand RsaF bare not involved in either the maintenance of membrane stability or the active export of antimicrobial compounds. Rather, RsaF aand RsaF bare required to prevent intracellular accumulation and aggregation of the S-layer protein RsaA; deletion of RsaF aand RsaF bled to a general growth defect and lowered cellular fitness. Using Western blotting, transmission electron microscopy, and transcriptome sequencing (RNA-seq), we show that loss of both RsaF aand RsaF bled to accumulation of insoluble RsaA in the cytoplasm, which in turn caused upregulation of a number of genes involved in protein misfolding and degradation pathways. These findings provide new insight into the requirement for RsaF aand RsaF bin cellular fitness and tolerance to antimicrobial agents and further our understanding of the S-layer export mechanism on both the transcriptional and translational levels inC. crescentus. IMPORTANCEDecreased growth rate and reduced cell fitness are common side effects of protein production in overexpression systems. Inclusion bodies typically form inside the cell, largely due to a lack of sufficient export machinery to transport the overexpressed proteins to the extracellular environment. This phenomenon can conceivably also occur in natural systems. As one example of a system evolved to prevent intracellular protein accumulation, our study demonstrates thatCaulobacter crescentushas two homologous outer membrane transporter proteins that are involved in S-layer export. This is an interesting case study that demonstrates how bacteria can evolve redundancy to ensure adequate protein export functionality and maintain high cellular fitness. Moreover, we provide evidence that these two outer membrane proteins, although being the closestC. crescentushomologs to TolC inE. coli, do not process TolC functionality inC. crescentus.« less

Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

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

Overton, K. Wesley; Park, Dan M.; Yung, Mimi C.

ABSTRACT Surface layers, or S-layers, are two-dimensional protein arrays that form the outermost layer of many bacteria and archaea. They serve several functions, including physical protection of the cell from environmental threats. The high abundance of S-layer proteins necessitates a highly efficient export mechanism to transport the S-layer protein from the cytoplasm to the cell exterior.Caulobacter crescentusis unique in that it has two homologous, seemingly redundant outer membrane proteins, RsaF aand RsaF b, which together with other components form a type I protein translocation pathway for S-layer export. These proteins have homology toEscherichia coliTolC, the outer membrane channel of multidrugmore » efflux pumps. Here we provide evidence that, unlike TolC, RsaF aand RsaF bare not involved in either the maintenance of membrane stability or the active export of antimicrobial compounds. Rather, RsaF aand RsaF bare required to prevent intracellular accumulation and aggregation of the S-layer protein RsaA; deletion of RsaF aand RsaF bled to a general growth defect and lowered cellular fitness. Using Western blotting, transmission electron microscopy, and transcriptome sequencing (RNA-seq), we show that loss of both RsaF aand RsaF bled to accumulation of insoluble RsaA in the cytoplasm, which in turn caused upregulation of a number of genes involved in protein misfolding and degradation pathways. These findings provide new insight into the requirement for RsaF aand RsaF bin cellular fitness and tolerance to antimicrobial agents and further our understanding of the S-layer export mechanism on both the transcriptional and translational levels inC. crescentus. IMPORTANCEDecreased growth rate and reduced cell fitness are common side effects of protein production in overexpression systems. Inclusion bodies typically form inside the cell, largely due to a lack of sufficient export machinery to transport the overexpressed proteins to the extracellular environment. This phenomenon can conceivably also occur in natural systems. As one example of a system evolved to prevent intracellular protein accumulation, our study demonstrates thatCaulobacter crescentushas two homologous outer membrane transporter proteins that are involved in S-layer export. This is an interesting case study that demonstrates how bacteria can evolve redundancy to ensure adequate protein export functionality and maintain high cellular fitness. Moreover, we provide evidence that these two outer membrane proteins, although being the closestC. crescentushomologs to TolC inE. coli, do not process TolC functionality inC. crescentus.« less

Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

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

Overton, K. Wesley; Park, Dan M.; Yung, Mimi C.

Surface layers, or S-layers, are two-dimensional protein arrays that form the outermost layer of many bacteria and archaea. They serve several functions, including physical protection of the cell from environmental threats. The high abundance of S-layer proteins necessitates a highly efficient export mechanism to transport the S-layer protein from the cytoplasm to the cell exterior.Caulobacter crescentusis unique in that it has two homologous, seemingly redundant outer membrane proteins, RsaF aand RsaF b, which together with other components form a type I protein translocation pathway for S-layer export. These proteins have homology toEscherichia coliTolC, the outer membrane channel of multidrug effluxmore » pumps. Here we provide evidence that, unlike TolC, RsaF aand RsaF bare not involved in either the maintenance of membrane stability or the active export of antimicrobial compounds. Rather, RsaF aand RsaF bare required to prevent intracellular accumulation and aggregation of the S-layer protein RsaA; deletion of RsaF aand RsaF bled to a general growth defect and lowered cellular fitness. Using Western blotting, transmission electron microscopy, and transcriptome sequencing (RNA-seq), we show that loss of both RsaF aand RsaF bled to accumulation of insoluble RsaA in the cytoplasm, which in turn caused upregulation of a number of genes involved in protein misfolding and degradation pathways. These findings provide new insight into the requirement for RsaF aand RsaF bin cellular fitness and tolerance to antimicrobial agents and further our understanding of the S-layer export mechanism on both the transcriptional and translational levels inC. crescentus. IMPORTANCEDecreased growth rate and reduced cell fitness are common side effects of protein production in overexpression systems. Inclusion bodies typically form inside the cell, largely due to a lack of sufficient export machinery to transport the overexpressed proteins to the extracellular environment. This phenomenon can conceivably also occur in natural systems. As one example of a system evolved to prevent intracellular protein accumulation, our study demonstrates thatCaulobacter crescentushas two homologous outer membrane transporter proteins that are involved in S-layer export. This is an interesting case study that demonstrates how bacteria can evolve redundancy to ensure adequate protein export functionality and maintain high cellular fitness. Moreover, we provide evidence that these two outer membrane proteins, although being the closestC. crescentushomologs to TolC inE. coli, do not process TolC functionality inC. crescentus.« less

I. An introduction to the relation of physical activity to cognitive and brain health, and scholastic achievement.

PubMed

Hillman, Charles H

2014-12-01

The current pandemic of physical inactivity threatens both physical and cognitive health throughout the lifespan. This monograph describes the multidisciplinary study of aspects of childhood health and its relationship to cognitive and brain function, and scholastic performance. Specifically, we focus on physical activity and physical fitness along with nutrition and obesity; interconnected aspects of health that have declined over the past 30 years in children of industrialized nations. Although much emphasis has been placed on correcting physical aspects of these public health concerns, it is only more recently that attention has been paid to the relation between physical health and cognitive health among school age children. The monograph begins with an overview of current behavioral trends that compete with physical activity engagement and contribute to the failure to achieve the public health recommendations for physical activity among children in the United States. Following the epidemiological overview, the relation of childhood fitness to brain structure and function is examined among children with varying fitness levels. The observed dissimilarities between higher- and lower-fit children are discussed within the context of typical brain development. To broaden the scope of research presented herein, the relation of nutrient intake--among both undernourished and well-nourished children--and obesity on cognition and brain are discussed. Next, novel empirical data are presented from a correlational study that indicates a differential relation between childhood fitness and adiposity on various aspects of cognition. In an effort to provide a more comprehensive review, a later chapter is dedicated to describing a small body of literature investigating the relation of physical activity to special populations of children, including those with learning disorders. In doing so, practical applications as well as challenges and limitations of implementing physical activity into the lives of children with learning disabilities are described. Finally, a detailed review and historical analysis of the relation of physical activity to scholastic performance is provided. This translational chapter provides an important application of the laboratory findings to a real world setting in which children rely upon attention, memory, and learning for scholastic success. Accordingly, this monograph is directed toward timely and important public health issues related to chronic disease prevention as a function of childhood inactivity and obesity with the goal of linking health behaviors to cognitive and brain health, and scholastic performance. © 2014 The Society for Research in Child Development, Inc.

Association of physical fitness and fatness with cognitive function in women with fibromyalgia.

PubMed

Soriano-Maldonado, Alberto; Artero, Enrique G; Segura-Jiménez, Víctor; Aparicio, Virgina A; Estévez-López, Fernando; Álvarez-Gallardo, Inmaculada C; Munguía-Izquierdo, Diego; Casimiro-Andújar, Antonio J; Delgado-Fernández, Manuel; Ortega, Francisco B

2016-09-01

This study assessed the association of fitness and fatness with cognitive function in women with fibromyalgia, and the independent influence of their single components on cognitive tasks. A total of 468 women with fibromyalgia were included. Speed of information processing and working memory (Paced Auditory Serial Addition Task), as well as immediate and delayed recall, verbal learning and delayed recognition (Rey Auditory Verbal Learning Test) were assessed. Aerobic fitness, muscle strength, flexibility and motor agility were assessed with the Senior Fitness Test battery. Body mass index, percent body fat, fat-mass index and waist circumference were measured. Aerobic fitness was associated with attention and working memory (all, p < 0.05). All fitness components were generally associated with delayed recall, verbal learning and delayed recognition (all, p < 0.05). Aerobic fitness showed the most powerful association with attention, working memory, delayed recall and verbal learning, while motor agility was the most powerful indicator of delayed recognition. None of the fatness parameters were associated with any of the outcomes (all, p > 0.05). Our results suggest that fitness, but not fatness, is associated with cognitive function in women with fibromyalgia. Aerobic fitness appears to be the most powerful fitness component regarding the cognitive tasks evaluated.

An Empirical Study on Raman Peak Fitting and Its Application to Raman Quantitative Research.

PubMed

Yuan, Xueyin; Mayanovic, Robert A

2017-10-01

Fitting experimentally measured Raman bands with theoretical model profiles is the basic operation for numerical determination of Raman peak parameters. In order to investigate the effects of peak modeling using various algorithms on peak fitting results, the representative Raman bands of mineral crystals, glass, fluids as well as the emission lines from a fluorescent lamp, some of which were measured under ambient light whereas others under elevated pressure and temperature conditions, were fitted using Gaussian, Lorentzian, Gaussian-Lorentzian, Voigtian, Pearson type IV, and beta profiles. From the fitting results of the Raman bands investigated in this study, the fitted peak position, intensity, area and full width at half-maximum (FWHM) values of the measured Raman bands can vary significantly depending upon which peak profile function is used in the fitting, and the most appropriate fitting profile should be selected depending upon the nature of the Raman bands. Specifically, the symmetric Raman bands of mineral crystals and non-aqueous fluids are best fit using Gaussian-Lorentzian or Voigtian profiles, whereas the asymmetric Raman bands are best fit using Pearson type IV profiles. The asymmetric O-H stretching vibrations of H 2 O and the Raman bands of soda-lime glass are best fit using several Gaussian profiles, whereas the emission lines from a florescent light are best fit using beta profiles. Multiple peaks that are not clearly separated can be fit simultaneously, provided the residuals in the fitting of one peak will not affect the fitting of the remaining peaks to a significant degree. Once the resolution of the Raman spectrometer has been properly accounted for, our findings show that the precision in peak position and intensity can be improved significantly by fitting the measured Raman peaks with appropriate profiles. Nevertheless, significant errors in peak position and intensity were still observed in the results from fitting of weak and wide Raman bands having unnormalized intensity/FWHM ratios lower than 200 counts/cm -1 .

An Advanced Computational Approach to System of Systems Analysis & Architecting Using Agent-Based Behavioral Model

DTIC Science & Technology

2012-09-30

System N Agent « datatype » SoS Architecture -Receives Capabilities1 -Provides Capabilities1 1 -Provides Capabilities1 1 -Provides Capabilities1 -Updates 1...fitness, or objective function. The structure of the SoS Agent is depicted in Figure 10. SoS Agent Architecture « datatype » Initial SoS...Architecture «subsystem» Fuzzy Inference Engine FAM « datatype » Affordability « datatype » Flexibility « datatype » Performance « datatype » Robustness Input Input

Photometric functions for photoclinometry and other applications

USGS Publications Warehouse

McEwen, A.S.

1991-01-01

Least-squared fits to the brightness profiles across a disk or "limb darkening" described by Hapke's photometric function are found for the simpler Minnaert and lunar-Lambert functions. The simpler functions are needed to reduce the number of unknown parameters in photoclinometry, especially to distinguish the brightness variations of the surface materials from that due to the resolved topography. The limb darkening varies with the Hapke parameters for macroscopic roughness (??), the single-scattering albedo (w), and the asymmetry factor of the particle phase function (g). Both of the simpler functions generally provide good matches to the limb darkening described by Hapke's function, but the lunar-Lambert function is superior when viewing angles are high and when (??) is less than 30??. Although a nonunique solution for the Minnaert function at high phase angles has been described for smooth surfaces, the discrepancy decreases with increasing (??) and virtually disappears when (??) reaches 30?? to 40??. The variation in limb darkening with w and g, pronounced for smooth surfaces, is reduced or eliminated when the Hapke parameters are in the range typical of most planetary surfaces; this result simplifies the problem of photoclinometry across terrains with variable surface materials. The Minnaert or lunar-Lambert fits to published Hapke models will give photoclinometric solutions that are very similar (>1?? slope discrepancy) to the Hapke-function solutions for nearly all of the bodies and terrains thus far modeled by Hapke's function. ?? 1991.

The extended Lennard-Jones potential energy function: A simpler model for direct-potential-fit analysis

NASA Astrophysics Data System (ADS)

Hajigeorgiou, Photos G.

2016-12-01

An analytical model for the diatomic potential energy function that was recently tested as a universal function (Hajigeorgiou, 2010) has been further modified and tested as a suitable model for direct-potential-fit analysis. Applications are presented for the ground electronic states of three diatomic molecules: oxygen, carbon monoxide, and hydrogen fluoride. The adjustable parameters of the extended Lennard-Jones potential model are determined through nonlinear regression by fits to calculated rovibrational energy term values or experimental spectroscopic line positions. The model is shown to lead to reliable, compact and simple representations for the potential energy functions of these systems and could therefore be classified as a suitable and attractive model for direct-potential-fit analysis.

Estimating age at a specified length from the von Bertalanffy growth function

USGS Publications Warehouse

Ogle, Derek H.; Isermann, Daniel A.

2017-01-01

Estimating the time required (i.e., age) for fish in a population to reach a specific length (e.g., legal harvest length) is useful for understanding population dynamics and simulating the potential effects of length-based harvest regulations. The age at which a population reaches a specific mean length is typically estimated by fitting a von Bertalanffy growth function to length-at-age data and then rearranging the best-fit equation to solve for age at the specified length. This process precludes the use of standard frequentist methods to compute confidence intervals and compare estimates of age at the specified length among populations. We provide a parameterization of the von Bertalanffy growth function that has age at a specified length as a parameter. With this parameterization, age at a specified length is directly estimated, and standard methods can be used to construct confidence intervals and make among-group comparisons for this parameter. We demonstrate use of the new parameterization with two data sets.

Super-resolution pupil filtering for visual performance enhancement using adaptive optics

NASA Astrophysics Data System (ADS)

Zhao, Lina; Dai, Yun; Zhao, Junlei; Zhou, Xiaojun

2018-05-01

Ocular aberration correction can significantly improve visual function of the human eye. However, even under ideal aberration correction conditions, pupil diffraction restricts the resolution of retinal images. Pupil filtering is a simple super-resolution (SR) method that can overcome this diffraction barrier. In this study, a 145-element piezoelectric deformable mirror was used as a pupil phase filter because of its programmability and high fitting accuracy. Continuous phase-only filters were designed based on Zernike polynomial series and fitted through closed-loop adaptive optics. SR results were validated using double-pass point spread function images. Contrast sensitivity was further assessed to verify the SR effect on visual function. An F-test was conducted for nested models to statistically compare different CSFs. These results indicated CSFs for the proposed SR filter were significantly higher than the diffraction correction (p < 0.05). As such, the proposed filter design could provide useful guidance for supernormal vision optical correction of the human eye.

The acquisition of conditioned responding.

PubMed

Harris, Justin A

2011-04-01

This report analyzes the acquisition of conditioned responses in rats trained in a magazine approach paradigm. Following the suggestion by Gallistel, Fairhurst, and Balsam (2004), Weibull functions were fitted to the trial-by-trial response rates of individual rats. These showed that the emergence of responding was often delayed, after which the response rate would increase relatively gradually across trials. The fit of the Weibull function to the behavioral data of each rat was equaled by that of a cumulative exponential function incorporating a response threshold. Thus, the growth in conditioning strength on each trial can be modeled by the derivative of the exponential--a difference term of the form used in many models of associative learning (e.g., Rescorla & Wagner, 1972). Further analyses, comparing the acquisition of responding with a continuously reinforced stimulus (CRf) and a partially reinforced stimulus (PRf), provided further evidence in support of the difference term. In conclusion, the results are consistent with conventional models that describe learning as the growth of associative strength, incremented on each trial by an error-correction process.

Fitness Landscapes of Functional RNAs.

PubMed

Kun, Ádám; Szathmáry, Eörs

2015-08-21

The notion of fitness landscapes, a map between genotype and fitness, was proposed more than 80 years ago. For most of this time data was only available for a few alleles, and thus we had only a restricted view of the whole fitness landscape. Recently, advances in genetics and molecular biology allow a more detailed view of them. Here we review experimental and theoretical studies of fitness landscapes of functional RNAs, especially aptamers and ribozymes. We find that RNA structures can be divided into critical structures, connecting structures, neutral structures and forbidden structures. Such characterisation, coupled with theoretical sequence-to-structure predictions, allows us to construct the whole fitness landscape. Fitness landscapes then can be used to study evolution, and in our case the development of the RNA world.

Genome-wide Fitness Profiles Reveal a Requirement for Autophagy During Yeast Fermentation

PubMed Central

Piggott, Nina; Cook, Michael A.; Tyers, Mike; Measday, Vivien

2011-01-01

The ability of cells to respond to environmental changes and adapt their metabolism enables cell survival under stressful conditions. The budding yeast Saccharomyces cerevisiae (S. cerevisiae) is particularly well adapted to the harsh conditions of anaerobic wine fermentation. However, S. cerevisiae gene function has not been previously systematically interrogated under conditions of industrial fermentation. We performed a genome-wide study of essential and nonessential S. cerevisiae gene requirements during grape juice fermentation to identify deletion strains that are either depleted or enriched within the viable fermentative population. Genes that function in autophagy and ubiquitin-proteasome degradation are required for optimal survival during fermentation, whereas genes that function in ribosome assembly and peroxisome biogenesis impair fitness during fermentation. We also uncover fermentation phenotypes for 139 uncharacterized genes with no previously known cellular function. We demonstrate that autophagy is induced early in wine fermentation in a nitrogen-replete environment, suggesting that autophagy may be triggered by other forms of stress that arise during fermentation. These results provide insights into the complex fermentation process and suggest possible means for improvement of industrial fermentation strains. PMID:22384346

Differences in Brain Activity during a Verbal Associative Memory Encoding Task in High- and Low-fit Adolescents

PubMed Central

Herting, Megan M.; Nagel, Bonnie J.

2013-01-01

Aerobic fitness is associated with better memory performance as well as larger volumes in memory-related brain regions in children, adolescents, and elderly. It is unclear if aerobic exercise also influences learning and memory functional neural circuitry. Here, we examine brain activity in 17 high-fit (HF) and 17 low-fit (LF) adolescents during a subsequent memory encoding paradigm using fMRI. Despite similar memory performance, HF and LF youth displayed a number of differences in memory-related and default mode (DMN) brain regions during encoding later remembered versus forgotten word pairs. Specifically, HF youth displayed robust deactivation in DMN areas, including the ventral medial PFC and posterior cingulate cortex, whereas LF youth did not show this pattern. Furthermore, LF youth showed greater bilateral hippocampal and right superior frontal gyrus activation during encoding of later remembered versus forgotten word pairs. Follow-up task-dependent functional correlational analyses showed differences in hippocampus and DMN activity coupling during successful encoding between the groups, suggesting aerobic fitness during adolescents may impact functional connectivity of the hippocampus and DMN during memory encoding. To our knowledge, this study is the first to examine the influence of aerobic fitness on hippocampal function and memory-related neural circuitry using fMRI. Taken together with previous research, these findings suggest aerobic fitness can influence not only memory-related brain structure, but also brain function. PMID:23249350

Leaf bacterial diversity mediates plant diversity and ecosystem function relationships.

PubMed

Laforest-Lapointe, Isabelle; Paquette, Alain; Messier, Christian; Kembel, Steven W

2017-06-01

Research on biodiversity and ecosystem functioning has demonstrated links between plant diversity and ecosystem functions such as productivity. At other trophic levels, the plant microbiome has been shown to influence host plant fitness and function, and host-associated microbes have been proposed to influence ecosystem function through their role in defining the extended phenotype of host organisms However, the importance of the plant microbiome for ecosystem function has not been quantified in the context of the known importance of plant diversity and traits. Here, using a tree biodiversity-ecosystem functioning experiment, we provide strong support for the hypothesis that leaf bacterial diversity is positively linked to ecosystem productivity, even after accounting for the role of plant diversity. Our results also show that host species identity, functional identity and functional diversity are the main determinants of leaf bacterial community structure and diversity. Our study provides evidence of a positive correlation between plant-associated microbial diversity and terrestrial ecosystem productivity, and a new mechanism by which models of biodiversity-ecosystem functioning relationships can be improved.

Cosmic reionization on computers: The faint end of the galaxy luminosity function

DOE PAGES

Gnedin, Nickolay Y.

2016-07-01

Using numerical cosmological simulations completed under the “Cosmic Reionization On Computers” project, I explore theoretical predictions for the faint end of the galaxy UV luminosity functions atmore » $$z\\gtrsim 6$$. A commonly used Schechter function approximation with the magnitude cut at $${M}_{{\\rm{cut}}}\\sim -13$$ provides a reasonable fit to the actual luminosity function of simulated galaxies. When the Schechter functional form is forced on the luminosity functions from the simulations, the magnitude cut $${M}_{{\\rm{cut}}}$$ is found to vary between -12 and -14 with a mild redshift dependence. Here, an analytical model of reionization from Madau et al., as used by Robertson et al., provides a good description of the simulated results, which can be improved even further by adding two physically motivated modifications to the original Madau et al. equation.« less

Cosmic reionization on computers: The faint end of the galaxy luminosity function

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

Gnedin, Nickolay Y.

Using numerical cosmological simulations completed under the “Cosmic Reionization On Computers” project, I explore theoretical predictions for the faint end of the galaxy UV luminosity functions atmore » $$z\\gtrsim 6$$. A commonly used Schechter function approximation with the magnitude cut at $${M}_{{\\rm{cut}}}\\sim -13$$ provides a reasonable fit to the actual luminosity function of simulated galaxies. When the Schechter functional form is forced on the luminosity functions from the simulations, the magnitude cut $${M}_{{\\rm{cut}}}$$ is found to vary between -12 and -14 with a mild redshift dependence. Here, an analytical model of reionization from Madau et al., as used by Robertson et al., provides a good description of the simulated results, which can be improved even further by adding two physically motivated modifications to the original Madau et al. equation.« less

Weighted Least Squares Fitting Using Ordinary Least Squares Algorithms.

ERIC Educational Resources Information Center

Kiers, Henk A. L.

1997-01-01

A general approach for fitting a model to a data matrix by weighted least squares (WLS) is studied. The approach consists of iteratively performing steps of existing algorithms for ordinary least squares fitting of the same model and is based on maximizing a function that majorizes WLS loss function. (Author/SLD)

Structural Insights into Triglyceride Storage Mediated by Fat Storage-Inducing Transmembrane (FIT) Protein 2

PubMed Central

Gross, David A.; Snapp, Erik L.; Silver, David L.

2010-01-01

Fat storage-Inducing Transmembrane proteins 1 & 2 (FIT1/FITM1 and FIT2/FITM2) belong to a unique family of evolutionarily conserved proteins localized to the endoplasmic reticulum that are involved in triglyceride lipid droplet formation. FIT proteins have been shown to mediate the partitioning of cellular triglyceride into lipid droplets, but not triglyceride biosynthesis. FIT proteins do not share primary sequence homology with known proteins and no structural information is available to inform on the mechanism by which FIT proteins function. Here, we present the experimentally-solved topological models for FIT1 and FIT2 using N-glycosylation site mapping and indirect immunofluorescence techniques. These methods indicate that both proteins have six-transmembrane-domains with both N- and C-termini localized to the cytosol. Utilizing this model for structure-function analysis, we identified and characterized a gain-of-function mutant of FIT2 (FLL(157-9)AAA) in transmembrane domain 4 that markedly augmented the total number and mean size of lipid droplets. Using limited-trypsin proteolysis we determined that the FLL(157-9)AAA mutant has enhanced trypsin cleavage at K86 relative to wild-type FIT2, indicating a conformational change. Taken together, these studies indicate that FIT2 is a 6 transmembrane domain-containing protein whose conformation likely regulates its activity in mediating lipid droplet formation. PMID:20520733

Effectiveness of a balance-focused exercise program for enhancing functional fitness of older adults at risk of falling: A randomised controlled trial.

PubMed

Zhao, Yanan; Chung, Pak-Kwong; Tong, Tom K

This study examined the effectivenss of a balance-focused training program (i.e., Exercise for Balance Improvement Program, ExBP) in improving functional fitness of older nonfallers at risk of falling. Sixty-one participants were randomly assigned to receive 16 weeks of ExBP or Tai Chi (TC) training, or no treatment (CON) with an 8-week follow-up. The Senior Fitness Test battery was applied to assess functional fitness. After the intervention, results revealed significant improvements in all fitness components in the ExBP group. Compared with the CON group, the ExBP group demonstrated more improvements in lower extremity muscle strength, agility and balance, and aerobic endurance. The ExBP group also displayed more improvements in aerobic endurance than the TC group in posttest and follow-up test. Therefore, the balance-focused exercise can be applied as an effective way in improving overall functional fitness among older nonfallers who are at risk of falling. Copyright © 2017 Elsevier Inc. All rights reserved.

Three-Dimensional Surface Parameters and Multi-Fractal Spectrum of Corroded Steel

PubMed Central

Shanhua, Xu; Songbo, Ren; Youde, Wang

2015-01-01

To study multi-fractal behavior of corroded steel surface, a range of fractal surfaces of corroded surfaces of Q235 steel were constructed by using the Weierstrass-Mandelbrot method under a high total accuracy. The multi-fractal spectrum of fractal surface of corroded steel was calculated to study the multi-fractal characteristics of the W-M corroded surface. Based on the shape feature of the multi-fractal spectrum of corroded steel surface, the least squares method was applied to the quadratic fitting of the multi-fractal spectrum of corroded surface. The fitting function was quantitatively analyzed to simplify the calculation of multi-fractal characteristics of corroded surface. The results showed that the multi-fractal spectrum of corroded surface was fitted well with the method using quadratic curve fitting, and the evolution rules and trends were forecasted accurately. The findings can be applied to research on the mechanisms of corroded surface formation of steel and provide a new approach for the establishment of corrosion damage constitutive models of steel. PMID:26121468

Press-fit versus threaded acetabular cups in total hip arthroplasty: Functional and radiological results after five years.

PubMed

Ellenrieder, Martin; Bader, Rainer; Bergschmidt, Philipp; Mittelmeier, Wolfram

2016-03-01

Prospectively the outcome after total hip replacement with a new threaded acetabular cup design was compared to an established press-fit cup. After 1, 2 and 5 years, the 36-item Short Form Health Survey, Western Ontario and McMaster University Osteoarthritis Index and Harris Hip Score revealed no significant differences between the two groups (each group: n=42 patients), except for a higher Harris Hip Score in the threaded cup group after five years (p=0.02). After five years, one threaded cup had a mild radiolucent line without further signs of loosening. All other cups of both groups (98.6%) showed a full osseous integration. The cup inclination angle ranged from 41-58° (threaded cups) to 39-77° (press-fit cups). The new threaded cup provides equivalent clinical outcomes and osseous integration but more precise implant positioning compared to the press-fit design. No complications typically ascribed to threaded cups (acetabular fractures, bone resorption, nerve impairment) occurred.

Early-Time Observations of the GRB 050319 Optical Transient

NASA Astrophysics Data System (ADS)

Quimby, R. M.; Rykoff, E. S.; Yost, S. A.; Aharonian, F.; Akerlof, C. W.; Alatalo, K.; Ashley, M. C. B.; Göǧüş, E.; Güver, T.; Horns, D.; Kehoe, R. L.; Kιzιloǧlu, Ü.; Mckay, T. A.; Özel, M.; Phillips, A.; Schaefer, B. E.; Smith, D. A.; Swan, H. F.; Vestrand, W. T.; Wheeler, J. C.; Wren, J.

2006-03-01

We present the unfiltered ROTSE-III light curve of the optical transient associated with GRB 050319 beginning 4 s after the cessation of γ-ray activity. We fit a power-law function to the data using the revised trigger time given by Chincarini and coworkers, and a smoothly broken power-law to the data using the original trigger disseminated through the GCN notices. Including the RAPTOR data from Woźniak and coworkers, the best-fit power-law indices are α=-0.854+/-0.014 for the single power-law and α1=-0.364+0.020-0.019, α2=-0.881+0.030-0.031, with a break at tb=418+31-30 s for the smoothly broken fit. We discuss the fit results, with emphasis placed on the importance of knowing the true start time of the optical transient for this multipeaked burst. As Swift continues to provide prompt GRB locations, it becomes more important to answer the question, ``when does the afterglow begin?'' in order to correctly interpret the light curves.

Divergent allele advantage at MHC-DRB through direct and maternal genotypic effects and its consequences for allele pool composition and mating

PubMed Central

Lenz, Tobias L.; Mueller, Birte; Trillmich, Fritz; Wolf, Jochen B. W.

2013-01-01

It is still debated whether main individual fitness differences in natural populations can be attributed to genome-wide effects or to particular loci of outstanding functional importance such as the major histocompatibility complex (MHC). In a long-term monitoring project on Galápagos sea lions (Zalophus wollebaeki), we collected comprehensive fitness and mating data for a total of 506 individuals. Controlling for genome-wide inbreeding, we find strong associations between the MHC locus and nearly all fitness traits. The effect was mainly attributable to MHC sequence divergence and could be decomposed into contributions of own and maternal genotypes. In consequence, the population seems to have evolved a pool of highly divergent alleles conveying near-optimal MHC divergence even by random mating. Our results demonstrate that a single locus can significantly contribute to fitness in the wild and provide conclusive evidence for the ‘divergent allele advantage’ hypothesis, a special form of balancing selection with interesting evolutionary implications. PMID:23677346

Three-Dimensional Surface Parameters and Multi-Fractal Spectrum of Corroded Steel.

PubMed

Shanhua, Xu; Songbo, Ren; Youde, Wang

2015-01-01

To study multi-fractal behavior of corroded steel surface, a range of fractal surfaces of corroded surfaces of Q235 steel were constructed by using the Weierstrass-Mandelbrot method under a high total accuracy. The multi-fractal spectrum of fractal surface of corroded steel was calculated to study the multi-fractal characteristics of the W-M corroded surface. Based on the shape feature of the multi-fractal spectrum of corroded steel surface, the least squares method was applied to the quadratic fitting of the multi-fractal spectrum of corroded surface. The fitting function was quantitatively analyzed to simplify the calculation of multi-fractal characteristics of corroded surface. The results showed that the multi-fractal spectrum of corroded surface was fitted well with the method using quadratic curve fitting, and the evolution rules and trends were forecasted accurately. The findings can be applied to research on the mechanisms of corroded surface formation of steel and provide a new approach for the establishment of corrosion damage constitutive models of steel.

A General Family of Limited Information Goodness-of-Fit Statistics for Multinomial Data

ERIC Educational Resources Information Center

Joe, Harry; Maydeu-Olivares, Alberto

2010-01-01

Maydeu-Olivares and Joe (J. Am. Stat. Assoc. 100:1009-1020, "2005"; Psychometrika 71:713-732, "2006") introduced classes of chi-square tests for (sparse) multidimensional multinomial data based on low-order marginal proportions. Our extension provides general conditions under which quadratic forms in linear functions of cell residuals are…

Comparison of field theory models of interest rates with market data

NASA Astrophysics Data System (ADS)

Baaquie, Belal E.; Srikant, Marakani

2004-03-01

We calibrate and test various variants of field theory models of the interest rate with data from Eurodollar futures. Models based on psychological factors are seen to provide the best fit to the market. We make a model independent determination of the volatility function of the forward rates from market data.

76 FR 17130 - Office of Planning, Research and Evaluation Advisory Committee on Head Start Research and Evaluation

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-28

... Impact Study fits within this agenda. The Committee will provide advice regarding future research efforts... Planning, Research and Evaluation Advisory Committee on Head Start Research and Evaluation AGENCY... for Head Start Research and Evaluation. General Function of Committee: The Advisory Committee for Head...

GDINA and CDM Packages in R

ERIC Educational Resources Information Center

Rupp, André A.; van Rijn, Peter W.

2018-01-01

We review the GIDNA and CDM packages in R for fitting cognitive diagnosis/diagnostic classification models. We first provide a summary of their core capabilities and then use both simulated and real data to compare their functionalities in practice. We found that the most relevant routines in the two packages appear to be more similar than…

Dynamic Properties of the International Space Station throughout the Assembly Process

DTIC Science & Technology

1998-06-29

with the launch of the Russian-built FGB, or Functional Cargo Block (most fitting translation) atop a Russian Proton rocket in June of 1998. Phase Two...experiments were conducted in areas of plant growth, life sciences, and microgravity science. But more importantly, Mir-Shuttle operations presented...Configuration Rationale/Comments 30Jun 1998 1 A/R Russian Proton • Functional Cargo Block (FGB) • FGB is a self-supporting active vehicle. • It provides

A step-by-step guide to non-linear regression analysis of experimental data using a Microsoft Excel spreadsheet.

PubMed

Brown, A M

2001-06-01

The objective of this present study was to introduce a simple, easily understood method for carrying out non-linear regression analysis based on user input functions. While it is relatively straightforward to fit data with simple functions such as linear or logarithmic functions, fitting data with more complicated non-linear functions is more difficult. Commercial specialist programmes are available that will carry out this analysis, but these programmes are expensive and are not intuitive to learn. An alternative method described here is to use the SOLVER function of the ubiquitous spreadsheet programme Microsoft Excel, which employs an iterative least squares fitting routine to produce the optimal goodness of fit between data and function. The intent of this paper is to lead the reader through an easily understood step-by-step guide to implementing this method, which can be applied to any function in the form y=f(x), and is well suited to fast, reliable analysis of data in all fields of biology.

Incipient balancing selection through adaptive loss of aquaporins in natural Saccharomyces cerevisiae populations.

PubMed

Will, Jessica L; Kim, Hyun Seok; Clarke, Jessica; Painter, John C; Fay, Justin C; Gasch, Audrey P

2010-04-01

A major goal in evolutionary biology is to understand how adaptive evolution has influenced natural variation, but identifying loci subject to positive selection has been a challenge. Here we present the adaptive loss of a pair of paralogous genes in specific Saccharomyces cerevisiae subpopulations. We mapped natural variation in freeze-thaw tolerance to two water transporters, AQY1 and AQY2, previously implicated in freeze-thaw survival. However, whereas freeze-thaw-tolerant strains harbor functional aquaporin genes, the set of sensitive strains lost aquaporin function at least 6 independent times. Several genomic signatures at AQY1 and/or AQY2 reveal low variation surrounding these loci within strains of the same haplotype, but high variation between strain groups. This is consistent with recent adaptive loss of aquaporins in subgroups of strains, leading to incipient balancing selection. We show that, although aquaporins are critical for surviving freeze-thaw stress, loss of both genes provides a major fitness advantage on high-sugar substrates common to many strains' natural niche. Strikingly, strains with non-functional alleles have also lost the ancestral requirement for aquaporins during spore formation. Thus, the antagonistic effect of aquaporin function-providing an advantage in freeze-thaw tolerance but a fitness defect for growth in high-sugar environments-contributes to the maintenance of both functional and nonfunctional alleles in S. cerevisiae. This work also shows that gene loss through multiple missense and nonsense mutations, hallmarks of pseudogenization presumed to emerge after loss of constraint, can arise through positive selection.

Receiver functions from west Antarctica; crust and mantle properties from POLENET

NASA Astrophysics Data System (ADS)

Aster, R. C.; Chaput, J. A.; Hansen, S. E.; Nyblade, A.; Wiens, D. A.; Huerta, A. D.; Wilson, T. J.; Anandakrishnan, S.

2011-12-01

We use receiver functions to extract crustal thickness and mantle transition zone depths across a wide extent of West Antarctica and the Transantarctic mountains using POLENET data, including recently recovered data from a 14-station West Antarctic Rift Zone transect. An adaptive approach for generating and analyzing P-receiver functions over ice sheets and sedimentary basins (similar to Winberry and Anandakrishnan, 2004) is applied using an extended time multitaper deconvolution algorithm and forward modeling synthetic seismogram fitting. We model P-S receiver functions via a layer stripping methodology (beginning with the ice sheet, if present), and fit increasingly longer sections of synthetic receiver functions to model the multiples observed in the data derived receiver functions. We additionally calculate S-P receiver functions, which provide complementary structural constraints, to generate consistent common conversion point stacks to image crustal and upper mantle discontinuities under West Antarctica. Crust throughout West Antarctica is generally thin (23-29 km; comparable to the U.S. Basin and Range) with relative thickening under the Marie Byrd Land volcanic province (to 32 km) and the Transantarctic Mountains. All constrained west Antarctic crust is substantially thicker than that in the vicinity of Ross Island, where crust as thin as 17 km is inferred in the Terror Rift region.

Fitting psychometric functions using a fixed-slope parameter: an advanced alternative for estimating odor thresholds with data generated by ASTM E679.

PubMed

Peng, Mei; Jaeger, Sara R; Hautus, Michael J

2014-03-01

Psychometric functions are predominately used for estimating detection thresholds in vision and audition. However, the requirement of large data quantities for fitting psychometric functions (>30 replications) reduces their suitability in olfactory studies because olfactory response data are often limited (<4 replications) due to the susceptibility of human olfactory receptors to fatigue and adaptation. This article introduces a new method for fitting individual-judge psychometric functions to olfactory data obtained using the current standard protocol-American Society for Testing and Materials (ASTM) E679. The slope parameter of the individual-judge psychometric function is fixed to be the same as that of the group function; the same-shaped symmetrical sigmoid function is fitted only using the intercept. This study evaluated the proposed method by comparing it with 2 available methods. Comparison to conventional psychometric functions (fitted slope and intercept) indicated that the assumption of a fixed slope did not compromise precision of the threshold estimates. No systematic difference was obtained between the proposed method and the ASTM method in terms of group threshold estimates or threshold distributions, but there were changes in the rank, by threshold, of judges in the group. Overall, the fixed-slope psychometric function is recommended for obtaining relatively reliable individual threshold estimates when the quantity of data is limited.

Proposal for a candidate core-set of fitness and strength tests for patients with childhood or adult idiopathic inflammatory myopathies

PubMed Central

van der Stap, Djamilla K.D.; Rider, Lisa G.; Alexanderson, Helene; Huber, Adam M.; Gualano, Bruno; Gordon, Patrick; van der Net, Janjaap; Mathiesen, Pernille; Johnson, Liam G.; Ernste, Floranne C.; Feldman, Brian M.; Houghton, Kristin M.; Singh-Grewal, Davinder; Kutzbach, Abraham Garcia; Munters, Li Alemo; Takken, Tim

2015-01-01

OBJECTIVES Currently there are no evidence-based recommendations regarding which fitness and strength tests to use for patients with childhood or adult idiopathic inflammatory myopathies (IIM). This hinders clinicians and researchers in choosing the appropriate fitness- or muscle strength-related outcome measures for these patients. Through a Delphi survey, we aimed to identify a candidate core-set of fitness and strength tests for children and adults with IIM. METHODS Fifteen experts participated in a Delphi survey that consisted of five stages to achieve a consensus. Using an extensive search of published literature and through the expertise of the experts, a candidate core-set based on expert opinion and clinimetric properties was developed. Members of the International Myositis Assessment and Clinical Studies Group (IMACS) were invited to review this candidate core-set during the final stage, which led to a final candidate core-set. RESULTS A core-set of fitness- and strength-related outcome measures was identified for children and adults with IIM. For both children and adults, different tests were identified and selected for maximal aerobic fitness, submaximal aerobic fitness, anaerobic fitness, muscle strength tests and muscle function tests. CONCLUSIONS The core-set of fitness and strength-related outcome measures provided by this expert consensus process will assist practitioners and researchers in deciding which tests to use in IIM patients. This will improve the uniformity of fitness and strength tests across studies, thereby facilitating the comparison of study results and therapeutic exercise program outcomes among patients with IIM. PMID:26568594

Quantitative photoplethysmography: Lambert-Beer law or inverse function incorporating light scatter.

PubMed

Cejnar, M; Kobler, H; Hunyor, S N

1993-03-01

Finger blood volume is commonly determined from measurement of infra-red (IR) light transmittance using the Lambert-Beer law of light absorption derived for use in non-scattering media, even when such transmission involves light scatter around the phalangeal bone. Simultaneous IR transmittance and finger volume were measured over the full dynamic range of vascular volumes in seven subjects and outcomes compared with data fitted according to the Lambert-Beer exponential function and an inverse function derived for light attenuation by scattering materials. Curves were fitted by the least-squares method and goodness of fit was compared using standard errors of estimate (SEE). The inverse function gave a better data fit in six of the subjects: mean SEE 1.9 (SD 0.7, range 0.7-2.8) and 4.6 (2.2, 2.0-8.0) respectively (p < 0.02, paired t-test). Thus, when relating IR transmittance to blood volume, as occurs in the finger during measurements of arterial compliance, an inverse function derived from a model of light attenuation by scattering media gives more accurate results than the traditional exponential fit.

Cardiorespiratory fitness modifies the relationship between myocardial function and cerebral blood flow in older adults.

PubMed

Johnson, Nathan F; Gold, Brian T; Bailey, Alison L; Clasey, Jody L; Hakun, Jonathan G; White, Matthew; Long, Doug E; Powell, David K

2016-05-01

A growing body of evidence indicates that cardiorespiratory fitness attenuates some age-related cerebral declines. However, little is known about the role that myocardial function plays in this relationship. Brain regions with high resting metabolic rates, such as the default mode network (DMN), may be especially vulnerable to age-related declines in myocardial functions affecting cerebral blood flow (CBF). This study explored the relationship between a measure of myocardial mechanics, global longitudinal strain (GLS), and CBF to the DMN. In addition, we explored how cardiorespiratory affects this relationship. Participants were 30 older adults between the ages of 59 and 69 (mean age=63.73years, SD=2.8). Results indicated that superior cardiorespiratory fitness and myocardial mechanics were positively associated with DMN CBF. Moreover, results of a mediation analysis revealed that the relationship between GLS and DMN CBF was accounted for by individual differences in fitness. Findings suggest that benefits of healthy heart function to brain function are modified by fitness. Copyright © 2015 Elsevier Inc. All rights reserved.

APOE polymorphism as a potential determinant of functional fitness in the elderly regardless of nutritional status.

PubMed

Snejdrlova, Michaela; Kalvach, Zdenek; Topinkova, Eva; Vrablik, Michal; Prochazkova, Renata; Kvasilova, Marie; Lanska, Vera; Zlatohlavek, Lukas; Prusikova, Martina; Ceska, Richard

2011-01-01

Life expectancy is determined by a combination of genetic predisposition (~25%) and environmental influences (~75%). Nevertheless a stronger genetic influence is anticipated in long-living individuals. Apolipoprotein E (APOE) gene belongs among the most studied candidate genes of longevity. We evaluated the relation of APOE polymorphism and fitness status in the elderly. We examined a total number of 128 subjects, over 80 years of age. Using a battery of functional tests their fitness status was assessed and the subjects were stratified into 5 functional categories according to Spirduso´s classification. Biochemistry analysis was performed by enzymatic method using automated analyzers. APOE gene polymorphism was analysed performed using PCR-RFLP. APOE4 allele carriers had significantly worse fitness status compared to non-carriers (p=0.025). Multiple logistic regression analysis showed the APOE4 carriers had higher risk (p=0.05) of functional unfitness compared to APOE2/E3 individuals. APOE gene polymorphism seems be an important genetic contributor to frailty development in the elderly. While APOE2 carriers tend to remain functionally fit till higher age, the functional status of APOE4 carriers deteriorates more rapidly. © 2011 Neuroendocrinology Letters

The association between anthropometric measures and lung function in a population-based study of Canadian adults.

PubMed

Rowe, A; Hernandez, P; Kuhle, S; Kirkland, S

2017-10-01

Decreased lung function has health impacts beyond diagnosable lung disease. It is therefore important to understand the factors that may influence even small changes in lung function including obesity, physical fitness and physical activity. The aim of this study was to determine the anthropometric measure most useful in examining the association with lung function and to determine how physical activity and physical fitness influence this association. The current study used cross-sectional data on 4662 adults aged 40-79 years from the Canadian Health Measures Survey Cycles 1 and 2. Linear regression models were used to examine the association between the anthropometric and lung function measures (forced expiratory volume in 1 s [FEV 1 ] and forced vital capacity [FVC]); R 2 values were compared among models. Physical fitness and physical activity terms were added to the models and potential confounding was assessed. Models using sum of 5 skinfolds and waist circumference consistently had the highest R 2 values for FEV 1 and FVC, while models using body mass index consistently had among the lowest R 2 values for FEV 1 and FVC and for men and women. Physical activity and physical fitness were confounders of the relationships between waist circumference and the lung function measures. Waist circumference remained a significant predictor of FVC but not FEV 1 after adjustment for physical activity or physical fitness. Waist circumference is an important predictor of lung function. Physical activity and physical fitness should be considered as potential confounders of the relationship between anthropometric measures and lung function. Copyright © 2017. Published by Elsevier Ltd.

Tensor-guided fitting of subduction slab depths

USGS Publications Warehouse

Bazargani, Farhad; Hayes, Gavin P.

2013-01-01

Geophysical measurements are often acquired at scattered locations in space. Therefore, interpolating or fitting the sparsely sampled data as a uniform function of space (a procedure commonly known as gridding) is a ubiquitous problem in geophysics. Most gridding methods require a model of spatial correlation for data. This spatial correlation model can often be inferred from some sort of secondary information, which may also be sparsely sampled in space. In this paper, we present a new method to model the geometry of a subducting slab in which we use a data‐fitting approach to address the problem. Earthquakes and active‐source seismic surveys provide estimates of depths of subducting slabs but only at scattered locations. In addition to estimates of depths from earthquake locations, focal mechanisms of subduction zone earthquakes also provide estimates of the strikes of the subducting slab on which they occur. We use these spatially sparse strike samples and the Earth’s curved surface geometry to infer a model for spatial correlation that guides a blended neighbor interpolation of slab depths. We then modify the interpolation method to account for the uncertainties associated with the depth estimates.

Phytoplankton productivity in relation to light intensity: A simple equation

USGS Publications Warehouse

Peterson, D.H.; Perry, M.J.; Bencala, K.E.; Talbot, M.C.

1987-01-01

A simple exponential equation is used to describe photosynthetic rate as a function of light intensity for a variety of unicellular algae and higher plants where photosynthesis is proportional to (1-e-??1). The parameter ?? (=Ik-1) is derived by a simultaneous curve-fitting method, where I is incident quantum-flux density. The exponential equation is tested against a wide range of data and is found to adequately describe P vs. I curves. The errors associated with photosynthetic parameters are calculated. A simplified statistical model (Poisson) of photon capture provides a biophysical basis for the equation and for its ability to fit a range of light intensities. The exponential equation provides a non-subjective simultaneous curve fitting estimate for photosynthetic efficiency (a) which is less ambiguous than subjective methods: subjective methods assume that a linear region of the P vs. I curve is readily identifiable. Photosynthetic parameters ?? and a are used widely in aquatic studies to define photosynthesis at low quantum flux. These parameters are particularly important in estuarine environments where high suspended-material concentrations and high diffuse-light extinction coefficients are commonly encountered. ?? 1987.

Long-Term Effects of Physically Active Academic Lessons on Physical Fitness and Executive Functions in Primary School Children

ERIC Educational Resources Information Center

de Greeff, J. W.; Hartman, E.; Mullender-Wijnsma, M. J.; Bosker, R. J.; Doolaard, S.; Visscher, C.

2016-01-01

Integrating physical activity into the curriculum has potential health and cognitive benefits in primary school children. The aim of this study was to investigate the effects of physically active academic lessons on cardiovascular fitness, muscular fitness and executive functions. In the current randomized controlled trial, 499 second and third…

The massive end of the luminosity and stellar mass functions and clustering from CMASS to SDSS: evidence for and against passive evolution

NASA Astrophysics Data System (ADS)

Bernardi, M.; Meert, A.; Sheth, R. K.; Huertas-Company, M.; Maraston, C.; Shankar, F.; Vikram, V.

2016-02-01

We describe the luminosity function, based on Sérsic fits to the light profiles, of CMASS galaxies at z ˜ 0.55. Compared to previous estimates, our Sérsic-based reductions imply more luminous, massive galaxies, consistent with the effects of Sérsic- rather than Petrosian or de Vaucouleur-based photometry on the Sloan Digital Sky Survey (SDSS) main galaxy sample at z ˜ 0.1. This implies a significant revision of the high-mass end of the correlation between stellar and halo mass. Inferences about the evolution of the luminosity and stellar mass functions depend strongly on the assumed, and uncertain, k + e corrections. In turn, these depend on the assumed age of the population. Applying k + e corrections taken from fitting the models of Maraston et al. to the colours of both SDSS and CMASS galaxies, the evolution of the luminosity and stellar mass functions appears impressively passive, provided that the fits are required to return old ages. However, when matched in comoving number- or luminosity-density, the SDSS galaxies are less strongly clustered compared to their counterparts in CMASS. This rules out the passive evolution scenario, and, indeed, any minor merger scenarios which preserve the rank ordering in stellar mass of the population. Potential incompletenesses in the CMASS sample would further enhance this mismatch. Our analysis highlights the virtue of combining clustering measurements with number counts.

Integrated Information Increases with Fitness in the Evolution of Animats

PubMed Central

Edlund, Jeffrey A.; Chaumont, Nicolas; Hintze, Arend; Koch, Christof; Tononi, Giulio; Adami, Christoph

2011-01-01

One of the hallmarks of biological organisms is their ability to integrate disparate information sources to optimize their behavior in complex environments. How this capability can be quantified and related to the functional complexity of an organism remains a challenging problem, in particular since organismal functional complexity is not well-defined. We present here several candidate measures that quantify information and integration, and study their dependence on fitness as an artificial agent (“animat”) evolves over thousands of generations to solve a navigation task in a simple, simulated environment. We compare the ability of these measures to predict high fitness with more conventional information-theoretic processing measures. As the animat adapts by increasing its “fit” to the world, information integration and processing increase commensurately along the evolutionary line of descent. We suggest that the correlation of fitness with information integration and with processing measures implies that high fitness requires both information processing as well as integration, but that information integration may be a better measure when the task requires memory. A correlation of measures of information integration (but also information processing) and fitness strongly suggests that these measures reflect the functional complexity of the animat, and that such measures can be used to quantify functional complexity even in the absence of fitness data. PMID:22028639

FTIR Analysis of Functional Groups in Aerosol Particles

NASA Astrophysics Data System (ADS)

Shokri, S. M.; McKenzie, G.; Dransfield, T. J.

2012-12-01

Secondary organic aerosols (SOA) are suspensions of particulate matter composed of compounds formed from chemical reactions of organic species in the atmosphere. Atmospheric particulate matter can have impacts on climate, the environment and human health. Standardized techniques to analyze the characteristics and composition of complex secondary organic aerosols are necessary to further investigate the formation of SOA and provide a better understanding of the reaction pathways of organic species in the atmosphere. While Aerosol Mass Spectrometry (AMS) can provide detailed information about the elemental composition of a sample, it reveals little about the chemical moieties which make up the particles. This work probes aerosol particles deposited on Teflon filters using FTIR, based on the protocols of Russell, et al. (Journal of Geophysical Research - Atmospheres, 114, 2009) and the spectral fitting algorithm of Takahama, et al (submitted, 2012). To validate the necessary calibration curves for the analysis of complex samples, primary aerosols of key compounds (e.g., citric acid, ammonium sulfate, sodium benzoate) were generated, and the accumulated masses of the aerosol samples were related to their IR absorption intensity. These validated calibration curves were then used to classify and quantify functional groups in SOA samples generated in chamber studies by MIT's Kroll group. The fitting algorithm currently quantifies the following functionalities: alcohols, alkanes, alkenes, amines, aromatics, carbonyls and carboxylic acids.

Obesity, Cardiovascular Fitness, and Inhibition Function: An Electrophysiological Study

PubMed Central

Song, Tai-Fen; Chi, Lin; Chu, Chien-Heng; Chen, Feng-Tzu; Zhou, Chenglin; Chang, Yu-Kai

2016-01-01

The purpose of the present study was to examine how obesity and cardiovascular fitness are associated with the inhibition aspect of executive function from behavioral and electrophysiological perspectives. One hundred college students, aged 18–25 years, were categorized into four groups of equal size on the basis of body mass index and cardiovascular fitness: a normal-weight and high-fitness (NH) group, an obese-weight and high-fitness (OH) group, a normal-weight and low-fitness (NL) group, and an obese-weight and low-fitness (OL) group. Behavioral measures of response time and number of errors, as well as event-related potential measures of P3 and N1, were assessed during the Stroop Task. The results revealed that, in general, the NH group exhibited shorter response times and larger P3 amplitudes relative to the NL and OL groups, wherein the OL group exhibited the longest response time in the incongruent condition. No group differences in N1 indices were also revealed. These findings suggest that the status of being both normal weight and having high cardiovascular fitness is associated with better behavioral and later stages of electrophysiological indices of cognitive function. PMID:27512383

Expanding the RpoS/σS-Network by RNA Sequencing and Identification of σS-Controlled Small RNAs in Salmonella

PubMed Central

Lévi-Meyrueis, Corinne; Monteil, Véronique; Sismeiro, Odile; Dillies, Marie-Agnès; Monot, Marc; Jagla, Bernd; Coppée, Jean-Yves; Dupuy, Bruno; Norel, Françoise

2014-01-01

The RpoS/σS sigma subunit of RNA polymerase (RNAP) controls a global adaptive response that allows many Gram-negative bacteria to survive starvation and various stresses. σS also contributes to biofilm formation and virulence of the food-borne pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium). In this study, we used directional RNA-sequencing and complementary assays to explore the σS-dependent transcriptome of S. Typhimurium during late stationary phase in rich medium. This study confirms the large regulatory scope of σS and provides insights into the physiological functions of σS in Salmonella. Extensive regulation by σS of genes involved in metabolism and membrane composition, and down-regulation of the respiratory chain functions, were important features of the σS effects on gene transcription that might confer fitness advantages to bacterial cells and/or populations under starving conditions. As an example, we show that arginine catabolism confers a competitive fitness advantage in stationary phase. This study also provides a firm basis for future studies to address molecular mechanisms of indirect regulation of gene expression by σS. Importantly, the σS-controlled downstream network includes small RNAs that might endow σS with post-transcriptional regulatory functions. Of these, four (RyhB-1/RyhB-2, SdsR, SraL) were known to be controlled by σS and deletion of the sdsR locus had a competitive fitness cost in stationary phase. The σS-dependent control of seven additional sRNAs was confirmed in Northern experiments. These findings will inspire future studies to investigate molecular mechanisms and the physiological impact of post-transcriptional regulation by σS. PMID:24810289

Rovibrational Line Lists for Nine Isotopologues of CO Suitable for Modeling and Interpreting Spectra at Very High Temperatures and Diverse Environments

NASA Astrophysics Data System (ADS)

Li, G.; Gordon, I. E.; Rothman, L. S.; Tan, Y.; Hu, S.-M.; Kassi, S.; Campargue, A.

2014-06-01

In order to improve and extend the existing HITRAN database1 and HITEMP2data for carbon monoxide, the ro-vibrational line lists were computed for all transitions of nine isotopologues of the CO molecule, namely 12C16O, 12C17O, 12C18O, 13C16O, 13C17O, 13C18O, 14C16O, 14C17O, and 14C18O in the electronic ground state up to v = 41 and J = 150. Line positions and intensity calculations were carried out using a newly-determined piece-wise dipole moment function (DMF) in conjunction with the wavefunctions calculated from a previous experimentally-determined potential energy function of Coxon and Hajigeorgiou3. Ab initio calculations and a direct-fit method which simultaneously fits all the reliable experimental ro-vibrational matrix elements has been used to construct the piecewise dipole moment function. To provide additional input parameters into the fit, new Cavity Ring Down Spectroscopy experiments were carried out to enable measurements of the lines in the 4-0 band with low uncertainty (Grenoble) as well as the first measurements of lines in the 6-0 band (Hefei). Accurate partition sums have been derived through direct summation for a temperature range from 1 to 9000 Kelvin. A complete set of broadening and shift parameters is also provided and now include parameters induced by CO2 and H2 in order to aid planetary applications. as part of the GNU EPrints system , and is freely redistributable under the GPL .

Cardiovascular fitness and executive control during task-switching: an ERP study.

PubMed

Scisco, Jenna L; Leynes, P Andrew; Kang, Jie

2008-07-01

Cardiovascular fitness recently has been linked to executive control function in older adults. The present study examined the relationship between cardiovascular fitness and executive control in young adults using event-related potentials (ERPs). Participants completed a two-part experiment. In part one, a graded exercise test (GXT) was administered using a cycle ergometer to obtain VO(2)max, a measure of maximal oxygen uptake. High-fit participants had VO(2)max measures at or above the 70th percentile based on age and sex, and low-fit participants had VO(2)max measures at or below the 30th percentile. In part two, a task-switching paradigm was used to investigate executive control. Task-switching trials produced slower response times and greater amplitude for both the P3a and P3b components of the ERP relative to a non-switch trial block. No ERP components varied as a function of fitness group. These findings, combined with results from previous research, suggest that the relationship between greater cardiovascular fitness and better cognitive function emerges after early adulthood.

Gonioreflectometric properties of metal surfaces

NASA Astrophysics Data System (ADS)

Jaanson, P.; Manoocheri, F.; Mäntynen, H.; Gergely, M.; Widlowski, J.-L.; Ikonen, E.

2014-12-01

Angularly resolved measurements of scattered light from surfaces can provide useful information in various fields of research and industry, such as computer graphics, satellite based Earth observation etc. In practice, empirical or physics-based models are needed to interpolate the measurement results, because a thorough characterization of the surfaces under all relevant conditions may not be feasible. In this work, plain and anodized metal samples were prepared and measured optically for bidirectional reflectance distribution function (BRDF) and mechanically for surface roughness. Two models for BRDF (Torrance-Sparrow model and a polarimetric BRDF model) were fitted to the measured values. A better fit was obtained for plain metal surfaces than for anodized surfaces.

Modeling inelastic phonon scattering in atomic- and molecular-wire junctions

NASA Astrophysics Data System (ADS)

Paulsson, Magnus; Frederiksen, Thomas; Brandbyge, Mads

2005-11-01

Computationally inexpensive approximations describing electron-phonon scattering in molecular-scale conductors are derived from the nonequilibrium Green’s function method. The accuracy is demonstrated with a first-principles calculation on an atomic gold wire. Quantitative agreement between the full nonequilibrium Green’s function calculation and the newly derived expressions is obtained while simplifying the computational burden by several orders of magnitude. In addition, analytical models provide intuitive understanding of the conductance including nonequilibrium heating and provide a convenient way of parameterizing the physics. This is exemplified by fitting the expressions to the experimentally observed conductances through both an atomic gold wire and a hydrogen molecule.

Biological growth functions describe published site index curves for Lake States timber species.

Treesearch

Allen L. Lundgren; William A. Dolid

1970-01-01

Two biological growth functions, an exponential-monomolecular function and a simple monomolecular function, have been fit to published site index curves for 11 Lake States tree species: red, jack, and white pine, balsam fir, white and black spruce, tamarack, white-cedar, aspen, red oak, and paper birch. Both functions closely fit all published curves except those for...

VizieR Online Data Catalog: Metal enrichment in semi-analytical model (Cousin+, 2016)

NASA Astrophysics Data System (ADS)

Cousin, M.; Buat, V.; Boissier, S.; Bethermin, M.; Roehlly, Y. Genois M.

2016-04-01

The repository contains outputs from the different models: - m1: Classical (only hot gas) isotropic accretion scenario + Standard Shmidt Kennicutt law - m2: Bimodal accretion (cold streams) + Standard Shmidt Kennicutt law - m3: Classical (only hot gas) isotropic accretion scenario + ad-hoc non-star forming gas reservoir - m4: Bimodal accretion (cold streams) + ad-hoc non-star forming gas reservoir For each model of these models dada are saved in eGalICS_m*.fits file. All these fits-formated files are compatible with the TOPCAT software available on: http://www.star.bris.ac.uk/~mbt/topcat/ We also provide, for each Initial Mass Function available, a set of two fits-formated files associated to the chemodynamical library presented in the paper. For these two files, data are available for all metallicity bins used. - masslossrates_IMF.fits: The instantaneous total ejecta rate associated to a SSP for the six different main-ISM elements. - SNratesIMF.fits: The total SN rate (SNII+SNIa [nb/Gyr]) associated to a SSP, individual contribution of SNII and SNIa are also given. These files are available for four different IMFs: Salpeter+55 (1955ApJ...121..161S), Chabrier+03 (2003PASP..115..763C), Kroupa+93 (2001MNRAS.322..231K) and Scalo+98 (1998ASPC..142..201S. Both ejecta rates and SN rates are computed for the complete list of stellar ages provided in the BC03 spectra library. They are saved in fits-formated files and structured with different extensions corresponding to the different initial stellar metallicity bins. We finally provide the median star formation history, the median gas accretion history and the metal enrichment histories associated to our MW-sisters sample: MWsistershistories.dat If you used data associated to eGalICS semi-analytic model, please cite the following paper: Cousin et al., 2015A&A...575A..33C, "Toward a new modelling of gas flows in a semi-analytical model of galaxy formation and evolution" (3 data files).

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.

Simplified curve fits for the thermodynamic properties of equilibrium air

NASA Technical Reports Server (NTRS)

Srinivasan, S.; Tannehill, J. C.; Weilmuenster, K. J.

1987-01-01

New, improved curve fits for the thermodynamic properties of equilibrium air have been developed. The curve fits are for pressure, speed of sound, temperature, entropy, enthalpy, density, and internal energy. These curve fits can be readily incorporated into new or existing computational fluid dynamics codes if real gas effects are desired. The curve fits are constructed from Grabau-type transition functions to model the thermodynamic surfaces in a piecewise manner. The accuracies and continuity of these curve fits are substantially improved over those of previous curve fits. These improvements are due to the incorporation of a small number of additional terms in the approximating polynomials and careful choices of the transition functions. The ranges of validity of the new curve fits are temperatures up to 25 000 K and densities from 10 to the -7 to 10 to the 3d power amagats.

Hyper-Fit: Fitting Linear Models to Multidimensional Data with Multivariate Gaussian Uncertainties

NASA Astrophysics Data System (ADS)

Robotham, A. S. G.; Obreschkow, D.

2015-09-01

Astronomical data is often uncertain with errors that are heteroscedastic (different for each data point) and covariant between different dimensions. Assuming that a set of D-dimensional data points can be described by a (D - 1)-dimensional plane with intrinsic scatter, we derive the general likelihood function to be maximised to recover the best fitting model. Alongside the mathematical description, we also release the hyper-fit package for the R statistical language (http://github.com/asgr/hyper.fit) and a user-friendly web interface for online fitting (http://hyperfit.icrar.org). The hyper-fit package offers access to a large number of fitting routines, includes visualisation tools, and is fully documented in an extensive user manual. Most of the hyper-fit functionality is accessible via the web interface. In this paper, we include applications to toy examples and to real astronomical data from the literature: the mass-size, Tully-Fisher, Fundamental Plane, and mass-spin-morphology relations. In most cases, the hyper-fit solutions are in good agreement with published values, but uncover more information regarding the fitted model.

Age-dependent Fourier model of the shape of the isolated ex vivo human crystalline lens.

PubMed

Urs, Raksha; Ho, Arthur; Manns, Fabrice; Parel, Jean-Marie

2010-06-01

To develop an age-dependent mathematical model of the zero-order shape of the isolated ex vivo human crystalline lens, using one mathematical function, that can be subsequently used to facilitate the development of other models for specific purposes such as optical modeling and analytical and numerical modeling of the lens. Profiles of whole isolated human lenses (n=30) aged 20-69, were measured from shadow-photogrammetric images. The profiles were fit to a 10th-order Fourier series consisting of cosine functions in polar-co-ordinate system that included terms for tilt and decentration. The profiles were corrected using these terms and processed in two ways. In the first, each lens was fit to a 10th-order Fourier series to obtain thickness and diameter, while in the second, all lenses were simultaneously fit to a Fourier series equation that explicitly include linear terms for age to develop an age-dependent mathematical model for the whole lens shape. Thickness and diameter obtained from Fourier series fits exhibited high correlation with manual measurements made from shadow-photogrammetric images. The root-mean-squared-error of the age-dependent fit was 205 microm. The age-dependent equations provide a reliable lens model for ages 20-60 years. The contour of the whole human crystalline lens can be modeled with a Fourier series. Shape obtained from the age-dependent model described in this paper can be used to facilitate the development of other models for specific purposes such as optical modeling and analytical and numerical modeling of the lens. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

A review of predictive coding algorithms.

PubMed

Spratling, M W

2017-03-01

Predictive coding is a leading theory of how the brain performs probabilistic inference. However, there are a number of distinct algorithms which are described by the term "predictive coding". This article provides a concise review of these different predictive coding algorithms, highlighting their similarities and differences. Five algorithms are covered: linear predictive coding which has a long and influential history in the signal processing literature; the first neuroscience-related application of predictive coding to explaining the function of the retina; and three versions of predictive coding that have been proposed to model cortical function. While all these algorithms aim to fit a generative model to sensory data, they differ in the type of generative model they employ, in the process used to optimise the fit between the model and sensory data, and in the way that they are related to neurobiology. Copyright © 2016 Elsevier Inc. All rights reserved.

Flow Channel Influence of a Collision-Based Piezoelectric Jetting Dispenser on Jet Performance

PubMed Central

Deng, Guiling; Li, Junhui; Duan, Ji’an

2018-01-01

To improve the jet performance of a bi-piezoelectric jet dispenser, mathematical and simulation models were established according to the operating principle. In order to improve the accuracy and reliability of the simulation calculation, a viscosity model of the fluid was fitted to a fifth-order function with shear rate based on rheological test data, and the needle displacement model was fitted to a nine-order function with time based on real-time displacement test data. The results show that jet performance is related to the diameter of the nozzle outlet and the cone angle of the nozzle, and the impacts of the flow channel structure were confirmed. The approach of numerical simulation is confirmed by the testing results of droplet volume. It will provide a reliable simulation platform for mechanical collision-based jet dispensing and a theoretical basis for micro jet valve design and improvement. PMID:29677140

Feasibility of generating quantitative composition images in dual energy mammography: a simulation study

NASA Astrophysics Data System (ADS)

Lee, Donghoon; Kim, Ye-seul; Choi, Sunghoon; Lee, Haenghwa; Choi, Seungyeon; Kim, Hee-Joung

2016-03-01

Breast cancer is one of the most common malignancies in women. For years, mammography has been used as the gold standard for localizing breast cancer, despite its limitation in determining cancer composition. Therefore, the purpose of this simulation study is to confirm the feasibility of obtaining tumor composition using dual energy digital mammography. To generate X-ray sources for dual energy mammography, 26 kVp and 39 kVp voltages were generated for low and high energy beams, respectively. Additionally, the energy subtraction and inverse mapping functions were applied to provide compositional images. The resultant images showed that the breast composition obtained by the inverse mapping function with cubic fitting achieved the highest accuracy and least noise. Furthermore, breast density analysis with cubic fitting showed less than 10% error compare to true values. In conclusion, this study demonstrated the feasibility of creating individual compositional images and capability of analyzing breast density effectively.

A probabilistic approach to photovoltaic generator performance prediction

NASA Astrophysics Data System (ADS)

Khallat, M. A.; Rahman, S.

1986-09-01

A method for predicting the performance of a photovoltaic (PV) generator based on long term climatological data and expected cell performance is described. The equations for cell model formulation are provided. Use of the statistical model for characterizing the insolation level is discussed. The insolation data is fitted to appropriate probability distribution functions (Weibull, beta, normal). The probability distribution functions are utilized to evaluate the capacity factors of PV panels or arrays. An example is presented revealing the applicability of the procedure.

Dynamic data driven bidirectional reflectance distribution function measurement system

NASA Astrophysics Data System (ADS)

Nauyoks, Stephen E.; Freda, Sam; Marciniak, Michael A.

2014-09-01

The bidirectional reflectance distribution function (BRDF) is a fitted distribution function that defines the scatter of light off of a surface. The BRDF is dependent on the directions of both the incident and scattered light. Because of the vastness of the measurement space of all possible incident and reflected directions, the calculation of BRDF is usually performed using a minimal amount of measured data. This may lead to poor fits and uncertainty in certain regions of incidence or reflection. A dynamic data driven application system (DDDAS) is a concept that uses an algorithm on collected data to influence the collection space of future data acquisition. The authors propose a DDD-BRDF algorithm that fits BRDF data as it is being acquired and uses on-the-fly fittings of various BRDF models to adjust the potential measurement space. In doing so, it is hoped to find the best model to fit a surface and the best global fit of the BRDF with a minimum amount of collection space.

Reporting Recommended Patch Density from Vehicle Panel Vibration Convergence Studies using both DAF and TBL Fits of the Spatial Correlation Function

NASA Technical Reports Server (NTRS)

Smith, Andrew M.; Davis, Robert Ben; LaVerde, Bruce T.; Jones, Douglas C.; Band, Jonathon L.

2012-01-01

Using the patch method to represent the continuous spatial correlation function of a phased pressure field over a structural surface is an approximation. The approximation approaches the continuous function as patches become smaller. Plotting comparisons of the approximation vs the continuous function may provide insight revealing: (1) For what patch size/density should the approximation be very good? (2) What the approximation looks like when it begins to break down? (3) What the approximation looks like when the patch size is grossly too large. Following these observations with a convergence study using one FEM may allow us to see the importance of patch density. We may develop insights that help us to predict sufficient patch density to provide adequate convergence for the intended purpose frequency range of interest

Determining plasma parameters in cold, multi-species plasmas using Maxwell and Kappa distribution functions.

NASA Astrophysics Data System (ADS)

Jahn, J. M.; Denton, R. E.; Nose, M.; Bonnell, J. W.; Kurth, W. S.; Livadiotis, G.; Larsen, B.; Goldstein, J.

2016-12-01

Determining the total plasma density from ion data is essentially an impossible task for particle instruments. The lowest instrument energy threshold never includes the coldest particles (i.e., Emin> 0 eV), and any positive spacecraft charging—which is normal for a sunlit spacecraft—exacerbates the problem by shifting the detectable minimum energy to higher values. For ion data, traditionally field line resonance measurements of ULF waves in the magnetosphere have been used to determine the mass loading of magnetic field lines in this case. This approach delivers a reduced ion mass M that represents the mass ratio of all ions on a magnetic field line. For multi-species plasmas like the plasmasphere this bounds the problem, but it does not provide a unique solution. To at least estimate partial densities using particle instruments, one traditionally performs fits to the measured particle distribution functions under the assumption that the underlying particle distributions are Maxwellian. Uncertainties performing a fit aside, there is usually no possibility to detect a possible bi-Maxwellian distribution where one of the Maxwellians is very cold. The tail of such a distribution may fall completely below the low energy threshold of the measurement. In this paper we present a different approach to determining the fractional temperatures Ti and densities ni in a multi-species plasma. First, we describe and demonstrate an approach to determine Ti and ni that does not require fitting but relies more on the mathematical properties of the distribution functions. We apply our approach to Van Allen Probes measurements of the plasmaspheric H+, He+, and O+ distribution functions under the assumption that the particle distributions are Maxwellian. We compare our results to mass loading results from the Van Allen Probes field line resonance analyses (for composition) and to the total (electron) plasma density derived from the EFW and EMFISIS experiments. Then we expand our approach to allow for kappa distributions instead. While this introduces an additional degree of freedom and therefore requires fitting, our approach is still better constrained than the traditional Maxwell fitting and may hold the key to a better understanding of the true nature of plasmaspheric particle distributions.

Fitting of hearing aids with different technical parameters to a patient with dead regions

NASA Astrophysics Data System (ADS)

Hojan-Jezierska, Dorota; Skrodzka, Ewa

2009-01-01

The purpose of the study was to determine an optimal hearing aid fitting procedure for a patient with well diagnosed high-frequency ‘dead regions’ in both cochleas. The patient reported non-symmetrical hearing problems of sensorineural origin. For binaural amplification two similar independent hearing aids were used as well as a pair of dependent devices with an ear-to-ear function. Two fitting methods were used: DSLi/o and NAL-NL1, and four different strategies of fitting were tested: the initial fitting based on the DSLi/o or NAL-NL1 method with necessary loudness corrections, the second fitting taking into account all the available functions of hearing instruments, the third fitting (based on the second one) but with significantly reduced amplification well above one octave of frequency inside dead region, and the final fitting with significantly reduced gain slightly below one octave inside dead regions. The results of hearing aids fitting were assessed using an APHAB procedure.

Low temperature heat capacities and thermodynamic functions described by Debye-Einstein integrals.

PubMed

Gamsjäger, Ernst; Wiessner, Manfred

2018-01-01

Thermodynamic data of various crystalline solids are assessed from low temperature heat capacity measurements, i.e., from almost absolute zero to 300 K by means of semi-empirical models. Previous studies frequently present fit functions with a large amount of coefficients resulting in almost perfect agreement with experimental data. It is, however, pointed out in this work that special care is required to avoid overfitting. Apart from anomalies like phase transformations, it is likely that data from calorimetric measurements can be fitted by a relatively simple Debye-Einstein integral with sufficient precision. Thereby, reliable values for the heat capacities, standard enthalpies, and standard entropies at T  = 298.15 K are obtained. Standard thermodynamic functions of various compounds strongly differing in the number of atoms in the formula unit can be derived from this fitting procedure and are compared to the results of previous fitting procedures. The residuals are of course larger when the Debye-Einstein integral is applied instead of using a high number of fit coefficients or connected splines, but the semi-empiric fit coefficients keep their meaning with respect to physics. It is suggested to use the Debye-Einstein integral fit as a standard method to describe heat capacities in the range between 0 and 300 K so that the derived thermodynamic functions are obtained on the same theory-related semi-empiric basis. Additional fitting is recommended when a precise description for data at ultra-low temperatures (0-20 K) is requested.

Item Response Theory with Estimation of the Latent Population Distribution Using Spline-Based Densities

ERIC Educational Resources Information Center

Woods, Carol M.; Thissen, David

2006-01-01

The purpose of this paper is to introduce a new method for fitting item response theory models with the latent population distribution estimated from the data using splines. A spline-based density estimation system provides a flexible alternative to existing procedures that use a normal distribution, or a different functional form, for the…

An Evaluation of Perceptions of Form, Fit, Function (F3) Standardization on the Standard Inertial Navigation Unit (STD INU) Program.

DTIC Science & Technology

1987-12-01

support durring the first few years of operations, which provides an incentive for such innovations and defers the acquisition of AGE until the equipment...along with number of standard avionics programs worked and the ranks of each individual. Table 5. Expierence With Avionics Standardization Years

Physiology of Exercise for Physical Education and Athletics. Second Edition.

ERIC Educational Resources Information Center

deVries, Herbert A.

This three-part text, which is concerned with human functions under stress of muscular activity, provides a basis for the study of physical fitness and athletic training. Part 1 reviews pertinent areas of basic physiology. Muscles, the nervous system, the heart, respiratory system, exercise metabolism, and the endocrine system are reviewed. Part 2…

Pollen-tube growth rates in Collinsia heterophylla (Plantaginaceae): one-donor crosses reveal heritability but no effect on sporophytic-offspring fitness.

PubMed

Lankinen, Asa; Maad, Johanne; Armbruster, W Scott

2009-04-01

Evolutionary change in response to natural selection will occur only if a trait confers a selective advantage and there is heritable variation. Positive connections between pollen traits and fitness have been found, but few studies of heritability have been conducted, and they have yielded conflicting results. To understand better the evolutionary significance of pollen competition and its potential role in sexual selection, the heritability of pollen tube-growth rate and the relationship between this trait and sporophytic offspring fitness were investigated in Collinsia heterophylla. Because the question being asked was if female function benefited from obtaining genetically superior fathers by enhancing pollen competition, one-donor (per flower) crosses were used in order to exclude confounding effects of post-fertilization competition/allocation caused by multiple paternity. Each recipient plant was crossed with an average of five pollen donors. Pollen-tube growth rate and sporophytic traits were measured in both generations. Pollen-tube growth rate in vitro differed among donors, and the differences were correlated with in vivo growth rate averaged over two to four maternal plants. Pollen-tube growth rate showed significant narrow-sense heritability and evolvability in a father-offspring regression. However, this pollen trait did not correlate significantly with sporophytic-offspring fitness. These results suggest that pollen-tube growth rate can respond to selection via male function. The data presented here do not provide any support for the hypothesis that intense pollen competition enhances maternal plant fitness through increased paternity by higher-quality sporophytic fathers, although this advantage cannot be ruled out. These data are, however, consistent with the hypothesis that pollen competition is itself selectively advantageous, through both male and female function, by reducing the genetic load among successful gametophytic fathers (pollen), and reducing inbreeding depression associated with self-pollination in plants with mix-mating systems.

Pollen-tube growth rates in Collinsia heterophylla (Plantaginaceae): one-donor crosses reveal heritability but no effect on sporophytic-offspring fitness

PubMed Central

Lankinen, Åsa; Maad, Johanne; Armbruster, W. Scott

2009-01-01

Background and Aims Evolutionary change in response to natural selection will occur only if a trait confers a selective advantage and there is heritable variation. Positive connections between pollen traits and fitness have been found, but few studies of heritability have been conducted, and they have yielded conflicting results. To understand better the evolutionary significance of pollen competition and its potential role in sexual selection, the heritability of pollen tube-growth rate and the relationship between this trait and sporophytic offspring fitness were investigated in Collinsia heterophylla. Methods Because the question being asked was if female function benefited from obtaining genetically superior fathers by enhancing pollen competition, one-donor (per flower) crosses were used in order to exclude confounding effects of post-fertilization competition/allocation caused by multiple paternity. Each recipient plant was crossed with an average of five pollen donors. Pollen-tube growth rate and sporophytic traits were measured in both generations. Key Results Pollen-tube growth rate in vitro differed among donors, and the differences were correlated with in vivo growth rate averaged over two to four maternal plants. Pollen-tube growth rate showed significant narrow-sense heritability and evolvability in a father–offspring regression. However, this pollen trait did not correlate significantly with sporophytic-offspring fitness. Conclusions These results suggest that pollen-tube growth rate can respond to selection via male function. The data presented here do not provide any support for the hypothesis that intense pollen competition enhances maternal plant fitness through increased paternity by higher-quality sporophytic fathers, although this advantage cannot be ruled out. These data are, however, consistent with the hypothesis that pollen competition is itself selectively advantageous, through both male and female function, by reducing the genetic load among successful gametophytic fathers (pollen), and reducing inbreeding depression associated with self–pollination in plants with mix-mating systems. PMID:19202136

Dual learning processes underlying human decision-making in reversal learning tasks: functional significance and evidence from the model fit to human behavior

PubMed Central

Bai, Yu; Katahira, Kentaro; Ohira, Hideki

2014-01-01

Humans are capable of correcting their actions based on actions performed in the past, and this ability enables them to adapt to a changing environment. The computational field of reinforcement learning (RL) has provided a powerful explanation for understanding such processes. Recently, the dual learning system, modeled as a hybrid model that incorporates value update based on reward-prediction error and learning rate modulation based on the surprise signal, has gained attention as a model for explaining various neural signals. However, the functional significance of the hybrid model has not been established. In the present study, we used computer simulation in a reversal learning task to address functional significance in a probabilistic reversal learning task. The hybrid model was found to perform better than the standard RL model in a large parameter setting. These results suggest that the hybrid model is more robust against the mistuning of parameters compared with the standard RL model when decision-makers continue to learn stimulus-reward contingencies, which can create abrupt changes. The parameter fitting results also indicated that the hybrid model fit better than the standard RL model for more than 50% of the participants, which suggests that the hybrid model has more explanatory power for the behavioral data than the standard RL model. PMID:25161635

A Synthesis of Solar Cycle Prediction Techniques

NASA Technical Reports Server (NTRS)

Hathaway, David H.; Wilson, Robert M.; Reichmann, Edwin J.

1999-01-01

A number of techniques currently in use for predicting solar activity on a solar cycle timescale are tested with historical data. Some techniques, e.g., regression and curve fitting, work well as solar activity approaches maximum and provide a month-by-month description of future activity, while others, e.g., geomagnetic precursors, work well near solar minimum but only provide an estimate of the amplitude of the cycle. A synthesis of different techniques is shown to provide a more accurate and useful forecast of solar cycle activity levels. A combination of two uncorrelated geomagnetic precursor techniques provides a more accurate prediction for the amplitude of a solar activity cycle at a time well before activity minimum. This combined precursor method gives a smoothed sunspot number maximum of 154 plus or minus 21 at the 95% level of confidence for the next cycle maximum. A mathematical function dependent on the time of cycle initiation and the cycle amplitude is used to describe the level of solar activity month by month for the next cycle. As the time of cycle maximum approaches a better estimate of the cycle activity is obtained by including the fit between previous activity levels and this function. This Combined Solar Cycle Activity Forecast gives, as of January 1999, a smoothed sunspot maximum of 146 plus or minus 20 at the 95% level of confidence for the next cycle maximum.

Status of Cycle 23 Forecasts

NASA Technical Reports Server (NTRS)

Hathaway, D. H.

2000-01-01

A number of techniques for predicting solar activity on a solar cycle time scale are identified, described, and tested with historical data. Some techniques, e.g,, regression and curve-fitting, work well as solar activity approaches maximum and provide a month- by-month description of future activity, while others, e.g., geomagnetic precursors, work well near solar minimum but provide an estimate only of the amplitude of the cycle. A synthesis of different techniques is shown to provide a more accurate and useful forecast of solar cycle activity levels. A combination of two uncorrelated geomagnetic precursor techniques provides the most accurate prediction for the amplitude of a solar activity cycle at a time well before activity minimum. This precursor method gave a smoothed sunspot number maximum of 154+21 for cycle 23. A mathematical function dependent upon the time of cycle initiation and the cycle amplitude then describes the level of solar activity for the complete cycle. As the time of cycle maximum approaches a better estimate of the cycle activity is obtained by including the fit between recent activity levels and this function. This Combined Solar Cycle Activity Forecast now gives a smoothed sunspot maximum of 140+20 for cycle 23. The success of the geomagnetic precursors in predicting future solar activity suggests that solar magnetic phenomena at latitudes above the sunspot activity belts are linked to solar activity, which occurs many years later in the lower latitudes.

Fitness costs of worker specialization for ant societies

PubMed Central

Jongepier, Evelien; Foitzik, Susanne

2016-01-01

Division of labour is of fundamental importance for the success of societies, yet little is known about how individual specialization affects the fitness of the group as a whole. While specialized workers may be more efficient in the tasks they perform than generalists, they may also lack the flexibility to respond to rapid shifts in task needs. Such rigidity could impose fitness costs when societies face dynamic and unpredictable events, such as an attack by socially parasitic slavemakers. Here, we experimentally assess the colony-level fitness consequences of behavioural specialization in Temnothorax longispinosus ants that are attacked by the slavemaker ant T. americanus. We manipulated the social organization of 102 T. longispinosus colonies, based on the behavioural responses of all 3842 workers. We find that strict specialization is disadvantageous for a colony's annual reproduction and growth during slave raids. These fitness costs may favour generalist strategies in dynamic environments, as we also demonstrate that societies exposed to slavemakers in the field show a lower degree of specialization than those originating from slavemaker-free populations. Our findings provide an explanation for the ubiquity of generalists and highlight their importance for the flexibility and functional robustness of entire societies. PMID:26763706

Estimating selection through male fitness: three complementary methods illuminate the nature and causes of selection on flowering time

PubMed Central

Austen, Emily J.; Weis, Arthur E.

2016-01-01

Our understanding of selection through male fitness is limited by the resource demands and indirect nature of the best available genetic techniques. Applying complementary, independent approaches to this problem can help clarify evolution through male function. We applied three methods to estimate selection on flowering time through male fitness in experimental populations of the annual plant Brassica rapa: (i) an analysis of mating opportunity based on flower production schedules, (ii) genetic paternity analysis, and (iii) a novel approach based on principles of experimental evolution. Selection differentials estimated by the first method disagreed with those estimated by the other two, indicating that mating opportunity was not the principal driver of selection on flowering time. The genetic and experimental evolution methods exhibited striking agreement overall, but a slight discrepancy between the two suggested that negative environmental covariance between age at flowering and male fitness may have contributed to phenotypic selection. Together, the three methods enriched our understanding of selection on flowering time, from mating opportunity to phenotypic selection to evolutionary response. The novel experimental evolution method may provide a means of examining selection through male fitness when genetic paternity analysis is not possible. PMID:26911957

Charactering baseline shift with 4th polynomial function for portable biomedical near-infrared spectroscopy device

NASA Astrophysics Data System (ADS)

Zhao, Ke; Ji, Yaoyao; Pan, Boan; Li, Ting

2018-02-01

The continuous-wave Near-infrared spectroscopy (NIRS) devices have been highlighted for its clinical and health care applications in noninvasive hemodynamic measurements. The baseline shift of the deviation measurement attracts lots of attentions for its clinical importance. Nonetheless current published methods have low reliability or high variability. In this study, we found a perfect polynomial fitting function for baseline removal, using NIRS. Unlike previous studies on baseline correction for near-infrared spectroscopy evaluation of non-hemodynamic particles, we focused on baseline fitting and corresponding correction method for NIRS and found that the polynomial fitting function at 4th order is greater than the function at 2nd order reported in previous research. Through experimental tests of hemodynamic parameters of the solid phantom, we compared the fitting effect between the 4th order polynomial and the 2nd order polynomial, by recording and analyzing the R values and the SSE (the sum of squares due to error) values. The R values of the 4th order polynomial function fitting are all higher than 0.99, which are significantly higher than the corresponding ones of 2nd order, while the SSE values of the 4th order are significantly smaller than the corresponding ones of the 2nd order. By using the high-reliable and low-variable 4th order polynomial fitting function, we are able to remove the baseline online to obtain more accurate NIRS measurements.

Neutron spectroscopy with scintillation detectors using wavelets

NASA Astrophysics Data System (ADS)

Hartman, Jessica

The purpose of this research was to study neutron spectroscopy using the EJ-299-33A plastic scintillator. This scintillator material provided a novel means of detection for fast neutrons, without the disadvantages of traditional liquid scintillation materials. EJ-299-33A provided a more durable option to these materials, making it less likely to be damaged during handling. Unlike liquid scintillators, this plastic scintillator was manufactured from a non-toxic material, making it safer to use, as well as easier to design detectors. The material was also manufactured with inherent pulse shape discrimination abilities, making it suitable for use in neutron detection. The neutron spectral unfolding technique was developed in two stages. Initial detector response function modeling was carried out through the use of the MCNPX Monte Carlo code. The response functions were developed for a monoenergetic neutron flux. Wavelets were then applied to smooth the response function. The spectral unfolding technique was applied through polynomial fitting and optimization techniques in MATLAB. Verification of the unfolding technique was carried out through the use of experimentally determined response functions. These were measured on the neutron source based on the Van de Graff accelerator at the University of Kentucky. This machine provided a range of monoenergetic neutron beams between 0.1 MeV and 24 MeV, making it possible to measure the set of response functions of the EJ-299-33A plastic scintillator detector to neutrons of specific energies. The response of a plutonium-beryllium (PuBe) source was measured using the source available at the University of Nevada, Las Vegas. The neutron spectrum reconstruction was carried out using the experimentally measured response functions. Experimental data was collected in the list mode of the waveform digitizer. Post processing of this data focused on the pulse shape discrimination analysis of the recorded response functions to remove the effects of photons and allow for source characterization based solely on the neutron response. The unfolding technique was performed through polynomial fitting and optimization techniques in MATLAB, and provided an energy spectrum for the PuBe source.

Cost-effectiveness of one versus two sample faecal immunochemical testing for colorectal cancer screening.

PubMed

Goede, S Lucas; van Roon, Aafke H C; Reijerink, Jacqueline C I Y; van Vuuren, Anneke J; Lansdorp-Vogelaar, Iris; Habbema, J Dik F; Kuipers, Ernst J; van Leerdam, Monique E; van Ballegooijen, Marjolein

2013-05-01

The sensitivity and specificity of a single faecal immunochemical test (FIT) are limited. The performance of FIT screening can be improved by increasing the screening frequency or by providing more than one sample in each screening round. This study aimed to evaluate if two-sample FIT screening is cost-effective compared with one-sample FIT. The MISCAN-colon microsimulation model was used to estimate costs and benefits of strategies with either one or two-sample FIT screening. The FIT cut-off level varied between 50 and 200 ng haemoglobin/ml, and the screening schedule was varied with respect to age range and interval. In addition, different definitions for positivity of the two-sample FIT were considered: at least one positive sample, two positive samples, or the mean of both samples being positive. Within an exemplary screening strategy, biennial FIT from the age of 55-75 years, one-sample FIT provided 76.0-97.0 life-years gained (LYG) per 1000 individuals, at a cost of € 259,000-264,000 (range reflects different FIT cut-off levels). Two-sample FIT screening with at least one sample being positive provided 7.3-12.4 additional LYG compared with one-sample FIT at an extra cost of € 50,000-59,000. However, when all screening intervals and age ranges were considered, intensifying screening with one-sample FIT provided equal or more LYG at lower costs compared with two-sample FIT. If attendance to screening does not differ between strategies it is recommended to increase the number of screening rounds with one-sample FIT screening, before considering increasing the number of FIT samples provided per screening round.

Shuttle payload interface verification equipment study. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1976-01-01

A preliminary design analysis of a stand alone payload integration device (IVE) is provided that is capable of verifying payload compatibility in form, fit and function with the shuttle orbiter prior to on-line payload/orbiter operations. The IVE is a high fidelity replica of the orbiter payload accommodations capable of supporting payload functional checkout and mission simulation. A top level payload integration analysis developed detailed functional flow block diagrams of the payload integration process for the broad spectrum of P/L's and identified degree of orbiter data required by the payload user and potential applications of the IVE.

The Alberta moving beyond breast cancer (AMBER) cohort study: a prospective study of physical activity and health-related fitness in breast cancer survivors

PubMed Central

2012-01-01

Background Limited research has examined the association between physical activity, health-related fitness, and disease outcomes in breast cancer survivors. Here, we present the rationale and design of the Alberta Moving Beyond Breast Cancer (AMBER) Study, a prospective cohort study designed specifically to examine the role of physical activity and health-related fitness in breast cancer survivorship from the time of diagnosis and for the balance of life. The AMBER Study will examine the role of physical activity and health-related fitness in facilitating treatment completion, alleviating treatment side effects, hastening recovery after treatments, improving long term quality of life, and reducing the risks of disease recurrence, other chronic diseases, and premature death. Methods/Design The AMBER Study will enroll 1500 newly diagnosed, incident, stage I-IIIc breast cancer survivors in Alberta, Canada over a 5 year period. Assessments will be made at baseline (within 90 days of surgery), 1 year, and 3 years consisting of objective and self-reported measurements of physical activity, health-related fitness, blood collection, lymphedema, patient-reported outcomes, and determinants of physical activity. A final assessment at 5 years will measure patient-reported data only. The cohort members will be followed for an additional 5 years for disease outcomes. Discussion The AMBER cohort will answer key questions related to physical activity and health-related fitness in breast cancer survivors including: (1) the independent and interactive associations of physical activity and health-related fitness with disease outcomes (e.g., recurrence, breast cancer-specific mortality, overall survival), treatment completion rates, symptoms and side effects (e.g., pain, lymphedema, fatigue, neuropathy), quality of life, and psychosocial functioning (e.g., anxiety, depression, self-esteem, happiness), (2) the determinants of physical activity and health-related fitness including demographic, medical, social cognitive, and environmental variables, (3) the mediators of any observed associations between physical activity, health-related fitness, and health outcomes including biological, functional, and psychosocial, and (4) the moderators of any observed associations including demographic, medical, and biological/disease factors. Taken together, these data will provide a comprehensive inquiry into the outcomes, determinants, mechanisms, and moderators of physical activity and health-related fitness in breast cancer survivors. PMID:23153358

The correlation function for density perturbations in an expanding universe. IV - The evolution of the correlation function. [galaxy distribution

NASA Technical Reports Server (NTRS)

Mcclelland, J.; Silk, J.

1979-01-01

The evolution of the two-point correlation function for the large-scale distribution of galaxies in an expanding universe is studied on the assumption that the perturbation densities lie in a Gaussian distribution centered on any given mass scale. The perturbations are evolved according to the Friedmann equation, and the correlation function for the resulting distribution of perturbations at the present epoch is calculated. It is found that: (1) the computed correlation function gives a satisfactory fit to the observed function in cosmological models with a density parameter (Omega) of approximately unity, provided that a certain free parameter is suitably adjusted; (2) the power-law slope in the nonlinear regime reflects the initial fluctuation spectrum, provided that the density profile of individual perturbations declines more rapidly than the -2.4 power of distance; and (3) both positive and negative contributions to the correlation function are predicted for cosmological models with Omega less than unity.

The hunt for the perfect discounting function and a reckoning of time perception.

PubMed

Namboodiri, Vijay Mk; Hussain Shuler, Marshall G

2016-10-01

Making decisions that factor the cost of time is fundamental to survival. Yet, while it is readily appreciated that our perception of time is intimately involved in this process, theories regarding intertemporal decision-making and theories regarding time perception are treated, largely, independently. Even within these respective domains, models providing good fits to data fail to provide insight as to why, from a normative sense, those fits should take their apparent form. Conversely, normative models that proffer a rationalization for why an agent should weigh options in a particular way, or to perceive time in a particular way, fail to account for the full body of well-established experimental evidence. Here we review select, yet key advances in our understanding, identifying conceptual breakthroughs in the fields of intertemporal decision-making and in time perception, as well as their limits and failings in the face of hard-won experimental observation. On this background of accrued knowledge, a new conception unifying the domains of decision-making and time perception is put forward (Training-Integrated Maximization of Reinforcement Rate, TIMERR) to provide a better fit to observations and a more parsimonious reckoning of why we make choices, and thereby perceive time, the way we do. Copyright © 2016 Elsevier Ltd. All rights reserved.

The association between aerobic fitness and cognitive function in older men mediated by frontal lateralization.

PubMed

Hyodo, Kazuki; Dan, Ippeita; Kyutoku, Yasushi; Suwabe, Kazuya; Byun, Kyeongho; Ochi, Genta; Kato, Morimasa; Soya, Hideaki

2016-01-15

Previous studies have shown that higher aerobic fitness is related to higher cognitive function and higher task-related prefrontal activation in older adults. However, a holistic picture of these factors has yet to be presented. As a typical age-related change of brain activation, less lateralized activity in the prefrontal cortex during cognitive tasks has been observed in various neuroimaging studies. Thus, this study aimed to reveal the relationship between aerobic fitness, cognitive function, and frontal lateralization. Sixty male older adults each performed a submaximal incremental exercise test to determine their oxygen intake (V·O2) at ventilatory threshold (VT) in order to index their aerobic fitness. They performed a color-word Stroop task while prefrontal activation was monitored using functional near infrared spectroscopy. As an index of cognitive function, Stroop interference time was analyzed. Partial correlation analyses revealed significant correlations among higher VT, shorter Stroop interference time and greater left-lateralized dorsolateral prefrontal cortex (DLPFC) activation when adjusting for education. Moreover, mediation analyses showed that left-lateralized DLPFC activation significantly mediated the association between VT and Stroop interference time. These results suggest that higher aerobic fitness is associated with cognitive function via lateralized frontal activation in older adults. Copyright © 2015 Elsevier Inc. All rights reserved.

Adaptive optics system performance approximations for atmospheric turbulence correction

NASA Astrophysics Data System (ADS)

Tyson, Robert K.

1990-10-01

Analysis of adaptive optics system behavior often can be reduced to a few approximations and scaling laws. For atmospheric turbulence correction, the deformable mirror (DM) fitting error is most often used to determine a priori the interactuator spacing and the total number of correction zones required. This paper examines the mirror fitting error in terms of its most commonly used exponential form. The explicit constant in the error term is dependent on deformable mirror influence function shape and actuator geometry. The method of least squares fitting of discrete influence functions to the turbulent wavefront is compared to the linear spatial filtering approximation of system performance. It is found that the spatial filtering method overstimates the correctability of the adaptive optics system by a small amount. By evaluating fitting error for a number of DM configurations, actuator geometries, and influence functions, fitting error constants verify some earlier investigations.

Combined associations of sedentary behavior and cardiorespiratory fitness on cognitive function among older adults.

PubMed

Edwards, Meghan K; Loprinzi, Paul D

2017-02-15

Sedentary behavior, cardiorespiratory fitness, cognition and age are interrelated and associated with cardiovascular function. No study, however, has specifically evaluated the independent and combined associations of cardiorespiratory fitness and sedentary behavior on cognition, which was this study's purpose. Data from the 1999-2002 NHANES were used (N=2451; 60-85yrs). Sedentary behavior was assessed via self-report; cardiorespiratory fitness was assessed from a medical-related algorithm; and cognition function was assessed from the Digit Symbol Substitution Test (DSST). Being in the bottom quartile for sedentary behavior (β=2.13; 95% CI: 0.49-3.77; P=0.01) and the top quartile for cardiorespiratory fitness (β=7.48; 95% CI: 5.4-9.5; P<0.001) were independently associated with higher cognitive function. In the additive model, those with an index score of 1 (vs. 0) and 2 (vs. 0), respectively, had a 3.87 (β=3.87; 95% CI: 1.76-5.98; P=0.001) and 10.40 (β=10.4; 95% CI: 7.31-13.5; P<0.001) higher DSST score. High cardiorespiratory fitness and low sedentary behavior were jointly associated with the highest cognitive function. This has important cardiovascular implications as a progression of neurocognitive impairment is associated with increasingly severe manifestations of cardiovascular disease. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Youpi: YOUr processing PIpeline

NASA Astrophysics Data System (ADS)

Monnerville, Mathias; Sémah, Gregory

2012-03-01

Youpi is a portable, easy to use web application providing high level functionalities to perform data reduction on scientific FITS images. Built on top of various open source reduction tools released to the community by TERAPIX (http://terapix.iap.fr), Youpi can help organize data, manage processing jobs on a computer cluster in real time (using Condor) and facilitate teamwork by allowing fine-grain sharing of results and data. Youpi is modular and comes with plugins which perform, from within a browser, various processing tasks such as evaluating the quality of incoming images (using the QualityFITS software package), computing astrometric and photometric solutions (using SCAMP), resampling and co-adding FITS images (using SWarp) and extracting sources and building source catalogues from astronomical images (using SExtractor). Youpi is useful for small to medium-sized data reduction projects; it is free and is published under the GNU General Public License.

Is Each Light-Harvesting Complex Protein Important for Plant Fitness?1[w

PubMed Central

Ganeteg, Ulrika; Külheim, Carsten; Andersson, Jenny; Jansson, Stefan

2004-01-01

Many of the photosynthetic genes are conserved among all higher plants, indicating that there is strong selective pressure to maintain the genes of each protein. However, mutants of these genes often lack visible growth phenotypes, suggesting that they are important only under certain conditions or have overlapping functions. To assess the importance of specific genes encoding the light-harvesting complex (LHC) proteins for the survival of the plant in the natural environment, we have combined two different scientific traditions by using an ecological fitness assay on a set of genetically modified Arabidopsis plants with differing LHC protein contents. The fitness of all of the LHC-deficient plants was reduced in some of the growth environments, supporting the hypothesis that each of the genes has been conserved because they provide ecological flexibility, which is of great adaptive value given the highly variable conditions encountered in nature. PMID:14730076

Fitness Tracker for Weight Lifting Style Workouts

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

Wihl, B. M.

This document proposes an early, high level design for a fitness tracking system which can automatically log weight lifting style workouts. The system will provide an easy to use interface both physically through the use of several wireless wristband style motion trackers worn on the limbs, and graphically through a smartphone application. Exercise classification will be accomplished by calibration of the user’s specific motions. The system will accurately track a user’s workout, miscounting no more than one repetition in every 20, have sufficient battery life to last several hours, work with existing smartphones and have a cost similar to thosemore » of current fitness tracking devices. This document presents the mission background, current state-of-theart, stakeholders and their expectations, the proposed system’s context and concepts, implementation concepts, system requirements, first sublevel function decomposition, possible risks for the system, and a reflection on the design process.« less

Calculation of Thomson scattering spectral fits for interpenetrating flows

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

Swadling, G. F., E-mail: george.swadling@imperial.ac.uk; Lebedev, S. V., E-mail: george.swadling@imperial.ac.uk; Burdiak, G. C.

2014-12-15

Collective mode optical Thomson scattering has been used to investigate the interactions of radially convergent ablation flows in Tungsten wire arrays. These experiments were carried out at the Magpie pulsed power facility at Imperial College, London. Analysis of the scattered spectra has provided direct evidence of ablation stream interpenetration on the array axis, and has also revealed a previously unobserved axial deflection of the ablation streams towards the anode as they approach the axis. It is has been suggested that this deflection is caused by the presence of a static magnetic field, advected with the ablation streams, stagnated and accruedmore » around the axis. Analysis of the Thomson scattering spectra involved the calculation and fitting of the multi-component, non-relativistic, Maxwellian spectral density function S (k, ω). The method used to calculate the fits of the data are discussed in detail.« less

Functional training reduces body fat and improves functional fitness and cholesterol levels in postmenopausal women: a randomized clinical trial.

PubMed

Neves, Lucas M; Fortaleza, Ana C; Rossi, Fabrício E; Diniz, Tiego A; Codogno, Jamile S; Gobbo, Luis A; Gobbi, Sebastião; Freitas, Ismael F

2017-04-01

This randomized clinical trial with concealed allocations, and blinding of the assessors and the data analyst, was aimed at determining the effects of 16 weeks of functional training on the body composition, functional fitness and lipid profiles in postmenopausal women. The study began with 64 subjects (N.=32 functional training and N.=32 control group) and ended with 50 subjects (N.=28 functional training and N.=22 control group). The exercise was conducted in circuit training format with 8 stations related to the development of muscular strength (using elastic bands for resistance) plus 3 stations focused on balance, coordination, and agility. The training session also incorporated an 18 to 30 minute walk. The control group did not participate in the exercise programs during the period of study. The participants were evaluated before and after the training period as regards their body composition (fat and lean mass), functional fitness, abdominal strength and blood chemistry variables. Significant reductions were observed in all body composition variables related to fat (FM= -3.4 and Android FM= -7.7%) (P<0.05). The functional fitness components had significant improvements in coordination (-33.3%), strength (66.5%), agility (-19.5%) and aerobic capacity (-7%), and significant improvement in abdominal strength (188.2%). We observed significant improvements in total cholesterol (-4.4%) and HDL (-9.9%). The observed data lead us to conclude that functional training utilizing with elastic bands and unstable bases causes significantly improved in body composition, functional fitness and lipid profiles.

VizieR Online Data Catalog: Soft X-ray standards (Beuermann+, 2006)

NASA Astrophysics Data System (ADS)

Beuermann, K.; Burwitz, V.; Rauch, T.

2006-08-01

Table A1 contains the area correction functions to the Chandra LETG+HRCS effective areas for the negative and positive dispersion directions, alphaneg, alphapos, and their area-weighted mean alpha as well as the corrected effective areas for a gravity of HZ43A of logg=7.90. Tables A2 and A3 are for logg=7.80 and 8.00, respectively. The corrected area A is obtained as the recommended area of the Chandra November 2004 release (http://cxc.harvard.edu/cal/Letg, LETG/HRC-S Effective Area, updated November 2004), referred to as A0 in the paper, multiplied with the correction function alpha (see Section 4.4.1 of the paper for further explanation). The variation of the correction functions alpha and the corrected areas A between the three tables indicate their systematic errors around the nominal values of Table A1 which are depicted in Fig. 5 of the paper. The columns of Tables A1 to A3 provide the wavelength Lambda ({AA}), alphaneg, alphapos, alpha, Aneg (cm2), Apos (cm2), and A (cm2). The header to each Table contains the parameters of the respective fit. Table A4 contains the best-fit incident soft X-ray spectra of HZ43A, SiriusB, and RXJ1856-37 for a gravity of HZ43A of logg=7.90 as shown in Fig. 6 of the paper (see also Table 3 of the paper). Tables A5 and A6 are for logg=7.80 and 8.00, respectively. The best-fit spectra are based on the most recent version of the Tuebingen Model Atmosphere Package TMAP (Werner et al. 2003, in: Workshop on Stellar Atmosphere Modeling, eds. I. Hubeny, D. Mihalas, K. Werner, ASP Conf. Ser. 288, 31; Rauch & Deetjen 2003, ASP Conf. Ser. 288, 103). The columns of Tables A1 to A3 provide the wavelength Lambda ({AA}) and the photon fluxes of the three stars in photons/cm2/s/{AA}. The header to each Table contains the parameters of the respective fit. (6 data files).

Rational functional representation of flap noise spectra including correction for reflection effects

NASA Technical Reports Server (NTRS)

Miles, J. H.

1974-01-01

A rational function is presented for the acoustic spectra generated by deflection of engine exhaust jets for under-the-wing and over-the-wing versions of externally blown flaps. The functional representation is intended to provide a means for compact storage of data and for data analysis. The expressions are based on Fourier transform functions for the Strouhal normalized pressure spectral density, and on a correction for reflection effects based on Thomas' (1969) N-independent-source model extended by use of a reflected ray transfer function. Curve fit comparisons are presented for blown-flap data taken from turbofan engine tests and from large-scale cold-flow model tests. Application of the rational function to scrubbing noise theory is also indicated.

Tmd Factorization and Evolution for Tmd Correlation Functions

NASA Astrophysics Data System (ADS)

Mert Aybat, S.; Rogers, Ted C.

We discuss the application of transverse momentum dependent (TMD) factorization theorems to phenomenology. Our treatment relies on recent extensions of the Collins-Soper-Sterman (CSS) formalism. Emphasis is placed on the importance of using well-defined TMD parton distribution functions (PDFs) and fragmentation functions (FFs) in calculating the evolution of these objects. We explain how parametrizations of unpolarized TMDs can be obtained from currently existing fixed-scale Gaussian fits and previous implementations of the CSS formalism in the Drell-Yan process, and provide some examples. We also emphasize the importance of agreed-upon definitions for having an unambiguous prescription for calculating higher orders in the hard part, and provide examples of higher order calculations. We end with a discussion of strategies for extending the phenomenological applications of TMD factorization to situations beyond the unpolarized case.

On the Complexity of Item Response Theory Models.

PubMed

Bonifay, Wes; Cai, Li

2017-01-01

Complexity in item response theory (IRT) has traditionally been quantified by simply counting the number of freely estimated parameters in the model. However, complexity is also contingent upon the functional form of the model. We examined four popular IRT models-exploratory factor analytic, bifactor, DINA, and DINO-with different functional forms but the same number of free parameters. In comparison, a simpler (unidimensional 3PL) model was specified such that it had 1 more parameter than the previous models. All models were then evaluated according to the minimum description length principle. Specifically, each model was fit to 1,000 data sets that were randomly and uniformly sampled from the complete data space and then assessed using global and item-level fit and diagnostic measures. The findings revealed that the factor analytic and bifactor models possess a strong tendency to fit any possible data. The unidimensional 3PL model displayed minimal fitting propensity, despite the fact that it included an additional free parameter. The DINA and DINO models did not demonstrate a proclivity to fit any possible data, but they did fit well to distinct data patterns. Applied researchers and psychometricians should therefore consider functional form-and not goodness-of-fit alone-when selecting an IRT model.

Hormonally active phytochemicals and vertebrate evolution.

PubMed

Lambert, Max R; Edwards, Thea M

2017-06-01

Living plants produce a diversity of chemicals that share structural and functional properties with vertebrate hormones. Wildlife species interact with these chemicals either through consumption of plant materials or aquatic exposure. Accumulating evidence shows that exposure to these hormonally active phytochemicals (HAPs) often has consequences for behavior, physiology, and fecundity. These fitness effects suggest there is potential for an evolutionary response by vertebrates to HAPs. Here, we explore the toxicological HAP-vertebrate relationship in an evolutionary framework and discuss the potential for vertebrates to adapt to or even co-opt the effects of plant-derived chemicals that influence fitness. We lay out several hypotheses about HAPs and provide a path forward to test whether plant-derived chemicals influence vertebrate reproduction and evolution. Studies of phytochemicals with direct impacts on vertebrate reproduction provide an obvious and compelling system for studying evolutionary toxicology. Furthermore, an understanding of whether animal populations evolve in response to HAPs could provide insightful context for the study of rapid evolution and how animals cope with chemical agents in the environment.

The Dutch-Flemish PROMIS Physical Function item bank exhibited strong psychometric properties in patients with chronic pain.

PubMed

Crins, Martine H P; Terwee, Caroline B; Klausch, Thomas; Smits, Niels; de Vet, Henrica C W; Westhovens, Rene; Cella, David; Cook, Karon F; Revicki, Dennis A; van Leeuwen, Jaap; Boers, Maarten; Dekker, Joost; Roorda, Leo D

2017-07-01

The objective of this study was to assess the psychometric properties of the Dutch-Flemish Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function item bank in Dutch patients with chronic pain. A bank of 121 items was administered to 1,247 Dutch patients with chronic pain. Unidimensionality was assessed by fitting a one-factor confirmatory factor analysis and evaluating resulting fit statistics. Items were calibrated with the graded response model and its fit was evaluated. Cross-cultural validity was assessed by testing items for differential item functioning (DIF) based on language (Dutch vs. English). Construct validity was evaluated by calculation correlations between scores on the Dutch-Flemish PROMIS Physical Function measure and scores on generic and disease-specific measures. Results supported the Dutch-Flemish PROMIS Physical Function item bank's unidimensionality (Comparative Fit Index = 0.976, Tucker Lewis Index = 0.976) and model fit. Item thresholds targeted a wide range of physical function construct (threshold-parameters range: -4.2 to 5.6). Cross-cultural validity was good as four items only showed DIF for language and their impact on item scores was minimal. Physical Function scores were strongly associated with scores on all other measures (all correlations ≤ -0.60 as expected). The Dutch-Flemish PROMIS Physical Function item bank exhibited good psychometric properties. Development of a computer adaptive test based on the large bank is warranted. Copyright © 2017 Elsevier Inc. All rights reserved.

Functional Fitness Testing Results Following Long-Duration ISS Missions.

PubMed

Laughlin, Mitzi S; Guilliams, Mark E; Nieschwitz, Bruce A; Hoellen, David

2015-12-01

Long-duration spaceflight missions lead to the loss of muscle strength and endurance. Significant reduction in muscle function can be hazardous when returning from spaceflight. To document these losses, NASA developed medical requirements that include measures of functional strength and endurance. Results from this Functional Fitness Test (FFT) battery are also used to evaluate the effectiveness of in-flight exercise countermeasures. The purpose of this paper is to document results from the FFT and correlate this information with performance of in-flight exercise on board the International Space Station. The FFT evaluates muscular strength and endurance, flexibility, and agility and includes the following eight measures: sit and reach, cone agility, push-ups, pull-ups, sliding crunches, bench press, leg press, and hand grip dynamometry. Pre- to postflight functional fitness measurements were analyzed using dependent t-tests and correlation analyses were used to evaluate the relationship between functional fitness measurements and in-flight exercise workouts. Significant differences were noted post space flight with the sit and reach, cone agility, leg press, and hand grip measurements while other test scores were not significantly altered. The relationships between functional fitness and in-flight exercise measurements showed minimal to moderate correlations for most in-flight exercise training variables. The change in FFT results can be partially explained by in-flight exercise performance. Although there are losses documented in the FFT results, it is important to realize that the crewmembers are successfully performing activities of daily living and are considered functional for normal activities upon return to Earth.

Radiation Dose Assessments of Solar Particle Events with Spectral Representation at High Energies for the Improvement of Radiation Protection

NASA Technical Reports Server (NTRS)

Kim, Myung-Hee; Atwell, William; Tylka, Allan J.; Dietrich, William F.; Cucinotta, Francis A.

2010-01-01

For radiation dose assessments of major solar particle events (SPEs), spectral functional forms of SPEs have been made by fitting available satellite measurements up to approx.100 MeV. However, very high-energy protons (above 500 MeV) have been observed with neutron monitors (NMs) in ground level enhancements (GLEs), which generally present the most severe radiation hazards to astronauts. Due to technical difficulties in converting NM data into absolutely normalized fluence measurements, those functional forms were made with little or no use of NM data. A new analysis of NM data has found that a double power law in rigidity (the so-called Band function) generally provides a satisfactory representation of the combined satellite and NM data from approx.10 MeV to approx.10 GeV in major SPEs (Tylka & Dietrich 2009). We use the Band function fits to re-assess human exposures from large SPEs. Using different spectral representations of large SPEs, variations of exposure levels were compared. The results can be applied to the development of approaches of improved radiation protection for astronauts, as well as the optimization of mission planning and shielding for future space missions.

Spoken language and everyday functioning in 5-year-old children using hearing aids or cochlear implants.

PubMed

Cupples, Linda; Ching, Teresa Yc; Button, Laura; Seeto, Mark; Zhang, Vicky; Whitfield, Jessica; Gunnourie, Miriam; Martin, Louise; Marnane, Vivienne

2017-09-12

This study investigated the factors influencing 5-year language, speech and everyday functioning of children with congenital hearing loss. Standardised tests including PLS-4, PPVT-4 and DEAP were directly administered to children. Parent reports on language (CDI) and everyday functioning (PEACH) were collected. Regression analyses were conducted to examine the influence of a range of demographic variables on outcomes. Participants were 339 children enrolled in the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study. Children's average receptive and expressive language scores were approximately 1 SD below the mean of typically developing children, and scores on speech production and everyday functioning were more than 1 SD below. Regression models accounted for 70-23% of variance in scores across different tests. Earlier CI switch-on and higher non-verbal ability were associated with better outcomes in most domains. Earlier HA fitting and use of oral communication were associated with better outcomes on directly administered language assessments. Severity of hearing loss and maternal education influenced outcomes of children with HAs. The presence of additional disabilities affected outcomes of children with CIs. The findings provide strong evidence for the benefits of early HA fitting and early CI for improving children's outcomes.

Co-evolutionary data mining for fuzzy rules: automatic fitness function creation phase space, and experiments

NASA Astrophysics Data System (ADS)

Smith, James F., III; Blank, Joseph A.

2003-03-01

An approach is being explored that involves embedding a fuzzy logic based resource manager in an electronic game environment. Game agents can function under their own autonomous logic or human control. This approach automates the data mining problem. The game automatically creates a cleansed database reflecting the domain expert's knowledge, it calls a data mining function, a genetic algorithm, for data mining of the data base as required and allows easy evaluation of the information extracted. The co-evolutionary fitness functions, chromosomes and stopping criteria for ending the game are discussed. Genetic algorithm and genetic program based data mining procedures are discussed that automatically discover new fuzzy rules and strategies. The strategy tree concept and its relationship to co-evolutionary data mining are examined as well as the associated phase space representation of fuzzy concepts. The overlap of fuzzy concepts in phase space reduces the effective strategies available to adversaries. Co-evolutionary data mining alters the geometric properties of the overlap region known as the admissible region of phase space significantly enhancing the performance of the resource manager. Procedures for validation of the information data mined are discussed and significant experimental results provided.

A photometric function of planetary surfaces for gourmets

NASA Astrophysics Data System (ADS)

Shkuratov, Yuriy; Korokhin, Viktor; Shevchenko, Vasilij; Mikhalchenko, Olga; Belskaya, Irina; Kaydash, Vadym; Videen, Gorden; Zubko, Evgenij; Velikodsky, Yuriy

2018-03-01

A new photometric model with small number of parameters is presented. The model is based on an assumption that there exist such surfaces for which spatial brightness variations caused by small topography undulations can be reproduced exactly by corresponding spatial variations of albedo. This indistinguishability results in a differential equation suggesting a new photometric function that generalizes, in particular, the Akimov disk-function. Our model provides excellent fits in a wide phase-angle range for integral observations of asteroids of different albedos. We also carried out fitting to integral observations of the Moon and Mercury, confirming difficulties in describing Mercury's phase function at large phase angles, which were also found for the Hapke model. Comparisons of global latitude and longitude trends with our model calculations have shown good coincidence for the Moon. To retrieve the lunar trends, we use the phase-ratio technique, applying it to our telescope observations. Mapping the model parameters using LROC WAC data were carried out for a region comprising the Reiner Gamma formation. This mapping allows us to calculate phase-ratio images of the region, showing at large phase angles systematically steeper phase curves of young craters and smaller steepness for the very Reiner Gamma formation.

Validating independent ratings of executive functioning following acquired brain injury using Rasch analysis.

PubMed

Simblett, Sara K; Badham, Rachel; Greening, Kate; Adlam, Anna; Ring, Howard; Bateman, Andrew

2012-01-01

Assessment of everyday problems with executive functioning following acquired brain injury (ABI) is greatly valued by neurorehabilitation services. Reliance on self-report measures alone is problematic within this client group who may experience difficulties with awareness and memory. The construct validity and reliability of independent ratings (i.e., ratings provided by a carer/relative) on the Dysexecutive Questionnaire (DEX-I) was explored in this study. Consistent with the results recently reported on the self-rated version of the DEX (DEX-S; Simblett & Bateman, 2011 ), Rasch analysis completed on 271 responses to the DEX-I revealed that the scale did not fit the Rasch model and did not meet the assumption of unidimensionality, that is, a single underlying construct could not be found for the DEX-I that would allow development of an interval-level measure as a whole. Subscales, based on theoretical conceptualisations of executive functioning (Stuss, 2007 ) previously suggested for the DEX-S, were able to demonstrate fit to the Rasch model and unidimensionality. Reliability of independent responses to these subscales in comparison to self-reported ratings is discussed. These results contribute to a greater understanding of how assessment of executive functioning can be improved.

Phase I/II randomized trial of aerobic exercise in Parkinson disease in a community setting.

PubMed

Uc, Ergun Y; Doerschug, Kevin C; Magnotta, Vincent; Dawson, Jeffrey D; Thomsen, Teri R; Kline, Joel N; Rizzo, Matthew; Newman, Sara R; Mehta, Sonya; Grabowski, Thomas J; Bruss, Joel; Blanchette, Derek R; Anderson, Steven W; Voss, Michelle W; Kramer, Arthur F; Darling, Warren G

2014-07-29

To (1) investigate effects of aerobic walking on motor function, cognition, and quality of life in Parkinson disease (PD), and (2) compare safety, tolerability, and fitness benefits of different forms of exercise intervention: continuous/moderate intensity vs interval/alternating between low and vigorous intensity, and individual/neighborhood vs group/facility setting. Initial design was a 6-month, 2 × 2 randomized trial of different exercise regimens in independently ambulatory patients with PD. All arms were required to exercise 3 times per week, 45 minutes per session. Randomization to group/facility setting was not feasible because of logistical factors. Over the first 2 years, we randomized 43 participants to continuous or interval training. Because preliminary analyses suggested higher musculoskeletal adverse events in the interval group and lack of difference between training methods in improving fitness, the next 17 participants were allocated only to continuous training. Eighty-one percent of 60 participants completed the study with a mean attendance of 83.3% (95% confidence interval: 77.5%-89.0%), exercising at 46.8% (44.0%-49.7%) of their heart rate reserve. There were no serious adverse events. Across all completers, we observed improvements in maximum oxygen consumption, gait speed, Unified Parkinson's Disease Rating Scale sections I and III scores (particularly axial functions and rigidity), fatigue, depression, quality of life (e.g., psychological outlook), and flanker task scores (p < 0.05 to p < 0.001). Increase in maximum oxygen consumption correlated with improvements on the flanker task and quality of life (p < 0.05). Our preliminary study suggests that aerobic walking in a community setting is safe, well tolerated, and improves aerobic fitness, motor function, fatigue, mood, executive control, and quality of life in mild to moderate PD. This study provides Class IV evidence that in patients with PD, an aerobic exercise program improves aerobic fitness, motor function, fatigue, mood, and cognition. © 2014 American Academy of Neurology.

DATMAN: A reliability data analysis program using Bayesian updating

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

Becker, M.; Feltus, M.A.

1996-12-31

Preventive maintenance (PM) techniques focus on the prevention of failures, in particular, system components that are important to plant functions. Reliability-centered maintenance (RCM) improves on the PM techniques by introducing a set of guidelines by which to evaluate the system functions. It also minimizes intrusive maintenance, labor, and equipment downtime without sacrificing system performance when its function is essential for plant safety. Both the PM and RCM approaches require that system reliability data be updated as more component failures and operation time are acquired. Systems reliability and the likelihood of component failures can be calculated by Bayesian statistical methods, whichmore » can update these data. The DATMAN computer code has been developed at Penn State to simplify the Bayesian analysis by performing tedious calculations needed for RCM reliability analysis. DATMAN reads data for updating, fits a distribution that best fits the data, and calculates component reliability. DATMAN provides a user-friendly interface menu that allows the user to choose from several common prior and posterior distributions, insert new failure data, and visually select the distribution that matches the data most accurately.« less

A Semi-Analytical Method for the PDFs of A Ship Rolling in Random Oblique Waves

NASA Astrophysics Data System (ADS)

Liu, Li-qin; Liu, Ya-liu; Xu, Wan-hai; Li, Yan; Tang, You-gang

2018-03-01

The PDFs (probability density functions) and probability of a ship rolling under the random parametric and forced excitations were studied by a semi-analytical method. The rolling motion equation of the ship in random oblique waves was established. The righting arm obtained by the numerical simulation was approximately fitted by an analytical function. The irregular waves were decomposed into two Gauss stationary random processes, and the CARMA (2, 1) model was used to fit the spectral density function of parametric and forced excitations. The stochastic energy envelope averaging method was used to solve the PDFs and the probability. The validity of the semi-analytical method was verified by the Monte Carlo method. The C11 ship was taken as an example, and the influences of the system parameters on the PDFs and probability were analyzed. The results show that the probability of ship rolling is affected by the characteristic wave height, wave length, and the heading angle. In order to provide proper advice for the ship's manoeuvring, the parametric excitations should be considered appropriately when the ship navigates in the oblique seas.

A bottom-up characterization of transfer functions for synthetic biology designs: lessons from enzymology.

PubMed

Carbonell-Ballestero, Max; Duran-Nebreda, Salva; Montañez, Raúl; Solé, Ricard; Macía, Javier; Rodríguez-Caso, Carlos

2014-12-16

Within the field of synthetic biology, a rational design of genetic parts should include a causal understanding of their input-output responses-the so-called transfer function-and how to tune them. However, a commonly adopted strategy is to fit data to Hill-shaped curves without considering the underlying molecular mechanisms. Here we provide a novel mathematical formalization that allows prediction of the global behavior of a synthetic device by considering the actual information from the involved biological parts. This is achieved by adopting an enzymology-like framework, where transfer functions are described in terms of their input affinity constant and maximal response. As a proof of concept, we characterize a set of Lux homoserine-lactone-inducible genetic devices with different levels of Lux receptor and signal molecule. Our model fits the experimental results and predicts the impact of the receptor's ribosome-binding site strength, as a tunable parameter that affects gene expression. The evolutionary implications are outlined. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

Design of an x-ray telescope optics for XEUS

NASA Astrophysics Data System (ADS)

Graue, Roland; Kampf, Dirk; Wallace, Kotska; Lumb, David; Bavdaz, Marcos; Freyberg, Michael

2017-11-01

The X-ray telescope concept for XEUS is based on an innovative high performance and light weight Silicon Pore Optics technology. The XEUS telescope is segmented into 16 radial, thermostable petals providing the rigid optical bench structure of the stand alone XRay High Precision Tandem Optics. A fully representative Form Fit Function (FFF) Model of one petal is currently under development to demonstrate the outstanding lightweight telescope capabilities with high optically effective area. Starting from the envisaged system performance the related tolerance budgets were derived. These petals are made from ceramics, i.e. CeSiC. The structural and thermal performance of the petal shall be reported. The stepwise alignment and integration procedure on petal level shall be described. The functional performance and environmental test verification plan of the Form Fit Function Model and the test set ups are described in this paper. In parallel to the running development activities the programmatic and technical issues wrt. the FM telescope MAIT with currently 1488 Tandem Optics are under investigation. Remote controlled robot supported assembly, simultaneous active alignment and verification testing and decentralised time effective integration procedures shall be illustrated.

A note on anomalous band-gap variations in semiconductors with temperature

NASA Astrophysics Data System (ADS)

Chakraborty, P. K.; Mondal, B. N.

2018-03-01

An attempt is made to theoretically study the band-gap variations (ΔEg) in semiconductors with temperature following the works, did by Fan and O'Donnell et al. based on thermodynamic functions. The semiconductor band-gap reflects the bonding energy. An increase in temperature changes the chemical bondings, and electrons are promoted from valence band to conduction band. In their analyses, they made several approximations with respect to temperature and other fitting parameters leading to real values of band-gap variations with linear temperature dependences. In the present communication, we have tried to re-analyse the works, specially did by Fan, and derived an analytical model for ΔEg(T). Because, it was based on the second-order perturbation technique of thermodynamic functions. Our analyses are made without any approximations with respect to temperatures and other fitting parameters mentioned in the text, leading to a complex functions followed by an oscillating nature of the variations of ΔEg. In support of the existence of the oscillating energy band-gap variations with temperature in a semiconductor, possible physical explanations are provided to justify the experimental observation for various materials.

R package PRIMsrc: Bump Hunting by Patient Rule Induction Method for Survival, Regression and Classification

PubMed Central

Dazard, Jean-Eudes; Choe, Michael; LeBlanc, Michael; Rao, J. Sunil

2015-01-01

PRIMsrc is a novel implementation of a non-parametric bump hunting procedure, based on the Patient Rule Induction Method (PRIM), offering a unified treatment of outcome variables, including censored time-to-event (Survival), continuous (Regression) and discrete (Classification) responses. To fit the model, it uses a recursive peeling procedure with specific peeling criteria and stopping rules depending on the response. To validate the model, it provides an objective function based on prediction-error or other specific statistic, as well as two alternative cross-validation techniques, adapted to the task of decision-rule making and estimation in the three types of settings. PRIMsrc comes as an open source R package, including at this point: (i) a main function for fitting a Survival Bump Hunting model with various options allowing cross-validated model selection to control model size (#covariates) and model complexity (#peeling steps) and generation of cross-validated end-point estimates; (ii) parallel computing; (iii) various S3-generic and specific plotting functions for data visualization, diagnostic, prediction, summary and display of results. It is available on CRAN and GitHub. PMID:26798326

Should the SCOPA-COG be modified? A Rasch analysis perspective.

PubMed

Forjaz, M J; Frades-Payo, B; Rodriguez-Blazquez, C; Ayala, A; Martinez-Martin, P

2010-02-01

The SCales for Outcomes in PArkinson's disease-Cognition (SCOPA-COG) is a specific measure of cognitive function for Parkinson's disease (PD) patients. Previous studies, under the frame of the classic test theory, indicate satisfactory psychometric properties. The Rasch model, an item response theory approach, provides new information about the scale, as well as results in a linear scale. This study aims at analysing the SCOPA-COG according to the Rasch model and, on the basis of results, suggesting modification to the SCOPA-COG. Fit to the Rasch model was analysed using a sample of 384 PD patients. A good fit was obtained after rescoring for disordered thresholds. The person separation index, a reliability measure, was 0.83. Differential item functioning was observed by age for three items and by gender for one item. The SCOPA-COG is a unidimensional measure of global cognitive function in PD patients, with good scale targeting and no empirical evidence for use of the subscale scores. Its adequate reliability and internal construct validity were supported. The SCOPA-COG, with the proposed scoring scheme, generates true linear interval scores.

Estimating Dynamical Systems: Derivative Estimation Hints From Sir Ronald A. Fisher.

PubMed

Deboeck, Pascal R

2010-08-06

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 approach for estimating derivatives, Local Linear Approximation (LLA), produces estimates with correlated errors. Depending on the specific differential equation model used, such correlated errors can lead to severely biased estimates of differential equation model parameters. This article shows that the fitting of dynamical systems can be improved by estimating derivatives in a manner similar to that used to fit orthogonal polynomials. Two applications using simulated data compare the proposed method and a generalized form of LLA when used to estimate derivatives and when used to estimate differential equation model parameters. A third application estimates the frequency of oscillation in observations of the monthly deaths from bronchitis, emphysema, and asthma in the United Kingdom. These data are publicly available in the statistical program R, and functions in R for the method presented are provided.

Dissecting a complex chemical stress: chemogenomic profiling of plant hydrolysates

PubMed Central

Skerker, Jeffrey M; Leon, Dacia; Price, Morgan N; Mar, Jordan S; Tarjan, Daniel R; Wetmore, Kelly M; Deutschbauer, Adam M; Baumohl, Jason K; Bauer, Stefan; Ibáñez, Ana B; Mitchell, Valerie D; Wu, Cindy H; Hu, Ping; Hazen, Terry; Arkin, Adam P

2013-01-01

The efficient production of biofuels from cellulosic feedstocks will require the efficient fermentation of the sugars in hydrolyzed plant material. Unfortunately, plant hydrolysates also contain many compounds that inhibit microbial growth and fermentation. We used DNA-barcoded mutant libraries to identify genes that are important for hydrolysate tolerance in both Zymomonas mobilis (44 genes) and Saccharomyces cerevisiae (99 genes). Overexpression of a Z. mobilis tolerance gene of unknown function (ZMO1875) improved its specific ethanol productivity 2.4-fold in the presence of miscanthus hydrolysate. However, a mixture of 37 hydrolysate-derived inhibitors was not sufficient to explain the fitness profile of plant hydrolysate. To deconstruct the fitness profile of hydrolysate, we profiled the 37 inhibitors against a library of Z. mobilis mutants and we modeled fitness in hydrolysate as a mixture of fitness in its components. By examining outliers in this model, we identified methylglyoxal as a previously unknown component of hydrolysate. Our work provides a general strategy to dissect how microbes respond to a complex chemical stress and should enable further engineering of hydrolysate tolerance. PMID:23774757

Spatiotemporal Dynamics and Fitness Analysis of Global Oil Market: Based on Complex Network

PubMed Central

Wang, Minggang; Fang, Guochang; Shao, Shuai

2016-01-01

We study the overall topological structure properties of global oil trade network, such as degree, strength, cumulative distribution, information entropy and weight clustering. The structural evolution of the network is investigated as well. We find the global oil import and export networks do not show typical scale-free distribution, but display disassortative property. Furthermore, based on the monthly data of oil import values during 2005.01–2014.12, by applying random matrix theory, we investigate the complex spatiotemporal dynamic from the country level and fitness evolution of the global oil market from a demand-side analysis. Abundant information about global oil market can be obtained from deviating eigenvalues. The result shows that the oil market has experienced five different periods, which is consistent with the evolution of country clusters. Moreover, we find the changing trend of fitness function agrees with that of gross domestic product (GDP), and suggest that the fitness evolution of oil market can be predicted by forecasting GDP values. To conclude, some suggestions are provided according to the results. PMID:27706147

Effects of High-Intensity Interval Training versus Continuous Training on Physical Fitness, Cardiovascular Function and Quality of Life in Heart Failure Patients.

PubMed

Benda, Nathalie M M; Seeger, Joost P H; Stevens, Guus G C F; Hijmans-Kersten, Bregina T P; van Dijk, Arie P J; Bellersen, Louise; Lamfers, Evert J P; Hopman, Maria T E; Thijssen, Dick H J

2015-01-01

Physical fitness is an important prognostic factor in heart failure (HF). To improve fitness, different types of exercise have been explored, with recent focus on high-intensity interval training (HIT). We comprehensively compared effects of HIT versus continuous training (CT) in HF patients NYHA II-III on physical fitness, cardiovascular function and structure, and quality of life, and hypothesize that HIT leads to superior improvements compared to CT. Twenty HF patients (male:female 19:1, 64±8 yrs, ejection fraction 38±6%) were allocated to 12-weeks of HIT (10*1-minute at 90% maximal workload-alternated by 2.5 minutes at 30% maximal workload) or CT (30 minutes at 60-75% of maximal workload). Before and after intervention, we examined physical fitness (incremental cycling test), cardiac function and structure (echocardiography), vascular function and structure (ultrasound) and quality of life (SF-36, Minnesota living with HF questionnaire (MLHFQ)). Training improved maximal workload, peak oxygen uptake (VO2peak) related to the predicted VO2peak, oxygen uptake at the anaerobic threshold, and maximal oxygen pulse (all P<0.05), whilst no differences were present between HIT and CT (N.S.). We found no major changes in resting cardiovascular function and structure. SF-36 physical function score improved after training (P<0.05), whilst SF-36 total score and MLHFQ did not change after training (N.S.). Training induced significant improvements in parameters of physical fitness, although no evidence for superiority of HIT over CT was demonstrated. No major effect of training was found on cardiovascular structure and function or quality of life in HF patients NYHA II-III. Nederlands Trial Register NTR3671.

Fine-grained parallelization of fitness functions in bioinformatics optimization problems: gene selection for cancer classification and biclustering of gene expression data.

PubMed

Gomez-Pulido, Juan A; Cerrada-Barrios, Jose L; Trinidad-Amado, Sebastian; Lanza-Gutierrez, Jose M; Fernandez-Diaz, Ramon A; Crawford, Broderick; Soto, Ricardo

2016-08-31

Metaheuristics are widely used to solve large combinatorial optimization problems in bioinformatics because of the huge set of possible solutions. Two representative problems are gene selection for cancer classification and biclustering of gene expression data. In most cases, these metaheuristics, as well as other non-linear techniques, apply a fitness function to each possible solution with a size-limited population, and that step involves higher latencies than other parts of the algorithms, which is the reason why the execution time of the applications will mainly depend on the execution time of the fitness function. In addition, it is usual to find floating-point arithmetic formulations for the fitness functions. This way, a careful parallelization of these functions using the reconfigurable hardware technology will accelerate the computation, specially if they are applied in parallel to several solutions of the population. A fine-grained parallelization of two floating-point fitness functions of different complexities and features involved in biclustering of gene expression data and gene selection for cancer classification allowed for obtaining higher speedups and power-reduced computation with regard to usual microprocessors. The results show better performances using reconfigurable hardware technology instead of usual microprocessors, in computing time and power consumption terms, not only because of the parallelization of the arithmetic operations, but also thanks to the concurrent fitness evaluation for several individuals of the population in the metaheuristic. This is a good basis for building accelerated and low-energy solutions for intensive computing scenarios.

Differences in Physical Fitness and Cardiovascular Function Depend on BMI in Korean Men.

PubMed

So, Wi-Young; Choi, Dai-Hyuk

2010-01-01

We investigated the associations between cardiovascular function and both body mass index and physical fitness in Korean men. The subjects were 2,013 men, aged 20 to 83 years, who visited a health promotion center for a comprehensive medical and fitness test during 2006-2009. The WHO's Asia-Pacific Standard Report definition of BMI was used in this study. Fitness assessment of cardiorespiratory endurance, muscular strength, muscular endurance, flexibility, power, agility, and balance were evaluated by VO2max (ml/kg/min), grip strength (kg), sit-ups (reps/min), sit and reach (cm), vertical jump (cm), side steps (reps/30s), and standing on one leg with eyes closed (sec), respectively. For cardiovascular function, we evaluated systolic blood pressure (SBP), diastolic blood pressure (DBP), resting heart rate (RHR), double product (DP), and vital capacity. There were significant decreases in cardiorespiratory endurance (p < 0.001), power (p < 0.001), and balance (p < 0.001), and increases in muscular strength (p < 0.001). Further, cardiovascular function, including SBP (p < 0.001), DBP (p < 0.001), double product (p < 0.001), and vital capacity (p=0.006) appeared to be lower for the obesity group. We conclude that an obese person exhibits lower fitness level and weaker cardiovascular function than a normal person. Key pointsThe obese group had a lower fitness level, including cardiorespiratory endurance, power, and balance.Obese group demonstrated an increase in muscular strength.Obese group had higher blood pressure and weaker cardiovascular function, including DP and vital capacity, than the normal group.

Differences in Physical Fitness and Cardiovascular Function Depend on BMI in Korean Men

PubMed Central

So, Wi-Young; Choi, Dai-Hyuk

2010-01-01

We investigated the associations between cardiovascular function and both body mass index and physical fitness in Korean men. The subjects were 2,013 men, aged 20 to 83 years, who visited a health promotion center for a comprehensive medical and fitness test during 2006-2009. The WHO's Asia-Pacific Standard Report definition of BMI was used in this study. Fitness assessment of cardiorespiratory endurance, muscular strength, muscular endurance, flexibility, power, agility, and balance were evaluated by VO2max (ml/kg/min), grip strength (kg), sit-ups (reps/min), sit and reach (cm), vertical jump (cm), side steps (reps/30s), and standing on one leg with eyes closed (sec), respectively. For cardiovascular function, we evaluated systolic blood pressure (SBP), diastolic blood pressure (DBP), resting heart rate (RHR), double product (DP), and vital capacity. There were significant decreases in cardiorespiratory endurance (p < 0.001), power (p < 0.001), and balance (p < 0.001), and increases in muscular strength (p < 0.001). Further, cardiovascular function, including SBP (p < 0.001), DBP (p < 0.001), double product (p < 0.001), and vital capacity (p=0.006) appeared to be lower for the obesity group. We conclude that an obese person exhibits lower fitness level and weaker cardiovascular function than a normal person. Key points The obese group had a lower fitness level, including cardiorespiratory endurance, power, and balance. Obese group demonstrated an increase in muscular strength. Obese group had higher blood pressure and weaker cardiovascular function, including DP and vital capacity, than the normal group. PMID:24149691

A temperature-dependent coarse-grained model for the thermoresponsive polymer poly(N-isopropylacrylamide).

PubMed

Abbott, Lauren J; Stevens, Mark J

2015-12-28

A coarse-grained (CG) model is developed for the thermoresponsive polymer poly(N-isopropylacrylamide) (PNIPAM), using a hybrid top-down and bottom-up approach. Nonbonded parameters are fit to experimental thermodynamic data following the procedures of the SDK (Shinoda, DeVane, and Klein) CG force field, with minor adjustments to provide better agreement with radial distribution functions from atomistic simulations. Bonded parameters are fit to probability distributions from atomistic simulations using multi-centered Gaussian-based potentials. The temperature-dependent potentials derived for the PNIPAM CG model in this work properly capture the coil-globule transition of PNIPAM single chains and yield a chain-length dependence consistent with atomistic simulations.

Orthotic management for children with osteogenesis imperfecta.

PubMed

Weintrob, J C

1995-01-01

Fitting children and infants who have osteogenesis imperfecta (OI) with braces has posed substantial problems of implementation and patient management For the past twelve years bracing has been an important component of a patient research and management program conducted at the National Institutes of Health. By using the smallest manufactured parts and developing a wealth of experience, functional and well-fitting braces have been provided to a number of tiny and small children. Bracing allows these children to stand and walk earlier than would have otherwise been possible. Braces are used in conjunction with standing frames and parapodiums to increase a child's mobility. Less involved children have become good household and short distance ambulators with the use of braces.

Simple Harmonics Motion experiment based on LabVIEW interface for Arduino

NASA Astrophysics Data System (ADS)

Tong-on, Anusorn; Saphet, Parinya; Thepnurat, Meechai

2017-09-01

In this work, we developed an affordable modern innovative physics lab apparatus. The ultrasonic sensor is used to measure the position of a mass attached on a spring as a function of time. The data acquisition system and control device were developed based on LabVIEW interface for Arduino UNO R3. The experiment was designed to explain wave propagation which is modeled by simple harmonic motion. The simple harmonic system (mass and spring) was observed and the motion can be realized using curve fitting to the wave equation in Mathematica. We found that the spring constants provided by Hooke’s law and the wave equation fit are 9.9402 and 9.1706 N/m, respectively.

Ionotropic glutamate receptors made crystal clear.

PubMed

Bowie, Derek

2014-12-01

Two recent crystallographic studies of the full-length GluA2 AMPA receptor provide our first insights into how the modular domains of the tetrameric complex coordinate the process of activation. These findings herald a new era in the structure-function analyses of neurotransmitter receptors, a fitting achievement for the 'International Year of Crystallography'. Copyright © 2014 Elsevier Ltd. All rights reserved.

Analysis of spectra using correlation functions

NASA Technical Reports Server (NTRS)

Beer, Reinhard; Norton, Robert H.

1988-01-01

A novel method is presented for the quantitative analysis of spectra based on the properties of the cross correlation between a real spectrum and either a numerical synthesis or laboratory simulation. A new goodness-of-fit criterion called the heteromorphic coefficient H is proposed that has the property of being zero when a fit is achieved and varying smoothly through zero as the iteration proceeds, providing a powerful tool for automatic or near-automatic analysis. It is also shown that H can be rendered substantially noise-immune, permitting the analysis of very weak spectra well below the apparent noise level and, as a byproduct, providing Doppler shift and radial velocity information with excellent precision. The technique is in regular use in the Atmospheric Trace Molecule Spectroscopy (ATMOS) project and operates in an interactive, realtime computing environment with turn-around times of a few seconds or less.

Precision Determination of the Small-x Gluon from Charm Production at LHCb.

PubMed

Gauld, Rhorry; Rojo, Juan

2017-02-17

The small-x gluon in global fits of parton distributions is affected by large uncertainties from the lack of direct experimental constraints. In this Letter, we provide a precision determination of the small-x gluon from the exploitation of forward charm production data provided by LHCb for three different center-of-mass (c.m.) energies: 5 TeV, 7 TeV, and 13 TeV. The LHCb measurements are included in the parton distribution function (PDF) fit by means of normalized distributions and cross-section ratios between data taken at different c.m. values, R_{13/7} and R_{13/5}. We demonstrate that forward charm production leads to a reduction of the PDF uncertainties of the gluon down to x≃10^{-6} by up to an order of magnitude, with implications for high-energy colliders, cosmic ray physics, and neutrino astronomy.

Influence of Photoperiod on Hormones, Behavior, and Immune Function

PubMed Central

Walton, James C.; Weil, Zachary M.; Nelson, Randy J.

2011-01-01

Photoperiodism is the ability of plants and animals to measure environmental day length to ascertain time of year. Central to the evolution of photoperiodism in animals is the adaptive distribution of energetically challenging activities across the year to optimize reproductive fitness while balancing the energetic tradeoffs necessary for seasonally- appropriate survival strategies. The ability to accurately predict future events requires endogenous mechanisms to permit physiological anticipation of annual conditions. Day length provides a virtually noise free environmental signal to monitor and accurately predict time of the year. In mammals, melatonin provides the hormonal signal transducing day length. Duration of pineal melatonin is inversely related to day length and its secretion drives enduring changes in many physiological systems, including the HPA, HPG, and brain-gut axes, the autonomic nervous system, and the immune system. Thus, melatonin is the fulcrum mediating redistribution of energetic investment among physiological processes to maximize fitness and survival. PMID:21156187

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

Carter, Faustin Wirkus; Khaire, Trupti S.; Novosad, Valentyn

We present "scraps" (SuperConducting Analysis and Plotting Software), a Python package designed to aid in the analysis and visualization of large amounts of superconducting resonator data, specifically complex transmission as a function of frequency, acquired at many different temperatures and driving powers. The package includes a least-squares fitting engine as well as a Monte-Carlo Markov Chain sampler for sampling the posterior distribution given priors, marginalizing over nuisance parameters, and estimating covariances. A set of plotting tools for generating publication-quality figures is also provided in the package. Lastly, we discuss the functionality of the software and provide some examples of itsmore » utility on data collected from a niobium-nitride coplanar waveguide resonator fabricated at Argonne National Laboratory.« less

Solid-State Thyratron Replacement. Final Report

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

Roth, Ian

2017-12-12

Under this SBIR, DTI developed a solid-state switch as an alternative to legacy thyratron equipment. Our Phase II objective was to make a solid-state thyratron replacement that would provide equivalent or better performance, much higher reliability (at least a 20 year lifetime, compared to a thyratron’s two-year lifetime) and would sell for ~3x the cost of a thyratron, or less than $40k. We were successful in building a solid-state switch which could reliably function as a thyratron replacement. The unit was designed to directly replace the thyratrons currently being used at SLAC’s Linac Coherent Light Source (LCLS), and was builtmore » in a tank that was small enough to fit into the existing thyratron cabinet, providing a true form-fit-function replacement path. We tested the switch at the full operating specifications: 48 kV, 6.3 kA, and 1 µs risetime. We also demonstrated a peak-to-peak pulse jitter of 1.5 ns, which is five times shorter than is typical for thyratrons. This lower jitter would improve the performance of the LCLS beam. The predicted reliability is more than 80 years, which is 40 times greater than a thyratron.« less

Anatomically Realistic Three-Dimensional Meshes of the Pelvic Floor & Anal Canal for Finite Element Analysis

PubMed Central

Noakes, Kimberley F.; Bissett, Ian P.; Pullan, Andrew J.; Cheng, Leo K.

2014-01-01

Three anatomically realistic meshes, suitable for finite element analysis, of the pelvic floor and anal canal regions have been developed to provide a framework with which to examine the mechanics, via finite element analysis of normal function within the pelvic floor. Two cadaver-based meshes were produced using the Visible Human Project (male and female) cryosection data sets, and a third mesh was produced based on MR image data from a live subject. The Visible Man (VM) mesh included 10 different pelvic structures while the Visible Woman and MRI meshes contained 14 and 13 structures respectively. Each image set was digitized and then finite element meshes were created using an iterative fitting procedure with smoothing constraints calculated from ‘L’-curves. These weights produced accurate geometric meshes of each pelvic structure with average Root Mean Square (RMS) fitting errors of less than 1.15 mm. The Visible Human cadaveric data provided high resolution images, however, the cadaveric meshes lacked the normal dynamic form of living tissue and suffered from artifacts related to postmortem changes. The lower resolution MRI mesh was able to accurately portray structure of the living subject and paves the way for dynamic, functional modeling. PMID:18317929

EVA Health and Human Performance Benchmarking Study

NASA Technical Reports Server (NTRS)

Abercromby, A. F.; Norcross, J.; Jarvis, S. L.

2016-01-01

Multiple HRP Risks and Gaps require detailed characterization of human health and performance during exploration extravehicular activity (EVA) tasks; however, a rigorous and comprehensive methodology for characterizing and comparing the health and human performance implications of current and future EVA spacesuit designs does not exist. This study will identify and implement functional tasks and metrics, both objective and subjective, that are relevant to health and human performance, such as metabolic expenditure, suit fit, discomfort, suited postural stability, cognitive performance, and potentially biochemical responses for humans working inside different EVA suits doing functional tasks under the appropriate simulated reduced gravity environments. This study will provide health and human performance benchmark data for humans working in current EVA suits (EMU, Mark III, and Z2) as well as shirtsleeves using a standard set of tasks and metrics with quantified reliability. Results and methodologies developed during this test will provide benchmark data against which future EVA suits, and different suit configurations (eg, varied pressure, mass, CG) may be reliably compared in subsequent tests. Results will also inform fitness for duty standards as well as design requirements and operations concepts for future EVA suits and other exploration systems.

Model-checking techniques based on cumulative residuals.

PubMed

Lin, D Y; Wei, L J; Ying, Z

2002-03-01

Residuals have long been used for graphical and numerical examinations of the adequacy of regression models. Conventional residual analysis based on the plots of raw residuals or their smoothed curves is highly subjective, whereas most numerical goodness-of-fit tests provide little information about the nature of model misspecification. In this paper, we develop objective and informative model-checking techniques by taking the cumulative sums of residuals over certain coordinates (e.g., covariates or fitted values) or by considering some related aggregates of residuals, such as moving sums and moving averages. For a variety of statistical models and data structures, including generalized linear models with independent or dependent observations, the distributions of these stochastic processes tinder the assumed model can be approximated by the distributions of certain zero-mean Gaussian processes whose realizations can be easily generated by computer simulation. Each observed process can then be compared, both graphically and numerically, with a number of realizations from the Gaussian process. Such comparisons enable one to assess objectively whether a trend seen in a residual plot reflects model misspecification or natural variation. The proposed techniques are particularly useful in checking the functional form of a covariate and the link function. Illustrations with several medical studies are provided.

Runoff potentiality of a watershed through SCS and functional data analysis technique.

PubMed

Adham, M I; Shirazi, S M; Othman, F; Rahman, S; Yusop, Z; Ismail, Z

2014-01-01

Runoff potentiality of a watershed was assessed based on identifying curve number (CN), soil conservation service (SCS), and functional data analysis (FDA) techniques. Daily discrete rainfall data were collected from weather stations in the study area and analyzed through lowess method for smoothing curve. As runoff data represents a periodic pattern in each watershed, Fourier series was introduced to fit the smooth curve of eight watersheds. Seven terms of Fourier series were introduced for the watersheds 5 and 8, while 8 terms of Fourier series were used for the rest of the watersheds for the best fit of data. Bootstrapping smooth curve analysis reveals that watersheds 1, 2, 3, 6, 7, and 8 are with monthly mean runoffs of 29, 24, 22, 23, 26, and 27 mm, respectively, and these watersheds would likely contribute to surface runoff in the study area. The purpose of this study was to transform runoff data into a smooth curve for representing the surface runoff pattern and mean runoff of each watershed through statistical method. This study provides information of runoff potentiality of each watershed and also provides input data for hydrological modeling.

Runoff Potentiality of a Watershed through SCS and Functional Data Analysis Technique

PubMed Central

Adham, M. I.; Shirazi, S. M.; Othman, F.; Rahman, S.; Yusop, Z.; Ismail, Z.

2014-01-01

Runoff potentiality of a watershed was assessed based on identifying curve number (CN), soil conservation service (SCS), and functional data analysis (FDA) techniques. Daily discrete rainfall data were collected from weather stations in the study area and analyzed through lowess method for smoothing curve. As runoff data represents a periodic pattern in each watershed, Fourier series was introduced to fit the smooth curve of eight watersheds. Seven terms of Fourier series were introduced for the watersheds 5 and 8, while 8 terms of Fourier series were used for the rest of the watersheds for the best fit of data. Bootstrapping smooth curve analysis reveals that watersheds 1, 2, 3, 6, 7, and 8 are with monthly mean runoffs of 29, 24, 22, 23, 26, and 27 mm, respectively, and these watersheds would likely contribute to surface runoff in the study area. The purpose of this study was to transform runoff data into a smooth curve for representing the surface runoff pattern and mean runoff of each watershed through statistical method. This study provides information of runoff potentiality of each watershed and also provides input data for hydrological modeling. PMID:25152911

An individual-tree basal area growth model for loblolly pine stands

Treesearch

Paul A. Murphy; Michael G. Shelton

1996-01-01

Tree basal area growth has been modeled as a combination of a potential growth function and a modifier function, in which the potential function is fitted separately from open-grown tree data or a subset of the data and the modifier function includes stand and site variables. We propose a modification of this by simultaneously fitting both a growth component and a...

BASKET on-board software library

NASA Astrophysics Data System (ADS)

Luntzer, Armin; Ottensamer, Roland; Kerschbaum, Franz

2014-07-01

The University of Vienna is a provider of on-board data processing software with focus on data compression, such as used on board the highly successful Herschel/PACS instrument, as well as in the small BRITE-Constellation fleet of cube-sats. Current contributions are made to CHEOPS, SAFARI and PLATO. The effort was taken to review the various functions developed for Herschel and provide a consolidated software library to facilitate the work for future missions. This library is a shopping basket of algorithms. Its contents are separated into four classes: auxiliary functions (e.g. circular buffers), preprocessing functions (e.g. for calibration), lossless data compression (arithmetic or Rice coding) and lossy reduction steps (ramp fitting etc.). The "BASKET" has all functionality that is needed to create an on-board data processing chain. All sources are written in C, supplemented by optimized versions in assembly, targeting popular CPU architectures for space applications. BASKET is open source and constantly growing

An improved peak frequency shift method for Q estimation based on generalized seismic wavelet function

NASA Astrophysics Data System (ADS)

Wang, Qian; Gao, Jinghuai

2018-02-01

As a powerful tool for hydrocarbon detection and reservoir characterization, the quality factor, Q, provides useful information in seismic data processing and interpretation. In this paper, we propose a novel method for Q estimation. The generalized seismic wavelet (GSW) function was introduced to fit the amplitude spectrum of seismic waveforms with two parameters: fractional value and reference frequency. Then we derive an analytical relation between the GSW function and the Q factor of the medium. When a seismic wave propagates through a viscoelastic medium, the GSW function can be employed to fit the amplitude spectrum of the source and attenuated wavelets, then the fractional values and reference frequencies can be evaluated numerically from the discrete Fourier spectrum. After calculating the peak frequency based on the obtained fractional value and reference frequency, the relationship between the GSW function and the Q factor can be built by the conventional peak frequency shift method. Synthetic tests indicate that our method can achieve higher accuracy and be more robust to random noise compared with existing methods. Furthermore, the proposed method is applicable to different types of source wavelet. Field data application also demonstrates the effectiveness of our method in seismic attenuation and the potential in the reservoir characteristic.

Entorhinal volume, aerobic fitness, and recognition memory in healthy young adults: A voxel-based morphometry study.

PubMed

Whiteman, Andrew S; Young, Daniel E; Budson, Andrew E; Stern, Chantal E; Schon, Karin

2016-02-01

Converging evidence supports the hypothesis effects of aerobic exercise and environmental enrichment are beneficial for cognition, in particular for hippocampus-supported learning and memory. Recent work in humans suggests that exercise training induces changes in hippocampal volume, but it is not known if aerobic exercise and fitness also impact the entorhinal cortex. In animal models, aerobic exercise increases expression of growth factors, including brain derived neurotrophic factor (BDNF). This exercise-enhanced expression of growth hormones may boost synaptic plasticity, and neuronal survival and differentiation, potentially supporting function and structure in brain areas including but not limited to the hippocampus. Here, using voxel based morphometry and a standard graded treadmill test to determine cardio-respiratory fitness (Bruce protocol; ·VO2 max), we examined if entorhinal and hippocampal volumes were associated with cardio-respiratory fitness in healthy young adults (N=33). In addition, we examined if volumes were modulated by recognition memory performance and by serum BDNF, a putative marker of synaptic plasticity. Our results show a positive association between volume in right entorhinal cortex and cardio-respiratory fitness. In addition, average gray matter volume in the entorhinal cortex, bilaterally, was positively associated with memory performance. These data extend prior work on the cerebral effects of aerobic exercise and fitness to the entorhinal cortex in healthy young adults thus providing compelling evidence for a relationship between aerobic fitness and structure of the medial temporal lobe memory system. Copyright © 2015 Elsevier Inc. All rights reserved.

Forecasting mortality of road traffic injuries in China using seasonal autoregressive integrated moving average model.

PubMed

Zhang, Xujun; Pang, Yuanyuan; Cui, Mengjing; Stallones, Lorann; Xiang, Huiyun

2015-02-01

Road traffic injuries have become a major public health problem in China. This study aimed to develop statistical models for predicting road traffic deaths and to analyze seasonality of deaths in China. A seasonal autoregressive integrated moving average (SARIMA) model was used to fit the data from 2000 to 2011. Akaike Information Criterion, Bayesian Information Criterion, and mean absolute percentage error were used to evaluate the constructed models. Autocorrelation function and partial autocorrelation function of residuals and Ljung-Box test were used to compare the goodness-of-fit between the different models. The SARIMA model was used to forecast monthly road traffic deaths in 2012. The seasonal pattern of road traffic mortality data was statistically significant in China. SARIMA (1, 1, 1) (0, 1, 1)12 model was the best fitting model among various candidate models; the Akaike Information Criterion, Bayesian Information Criterion, and mean absolute percentage error were -483.679, -475.053, and 4.937, respectively. Goodness-of-fit testing showed nonautocorrelations in the residuals of the model (Ljung-Box test, Q = 4.86, P = .993). The fitted deaths using the SARIMA (1, 1, 1) (0, 1, 1)12 model for years 2000 to 2011 closely followed the observed number of road traffic deaths for the same years. The predicted and observed deaths were also very close for 2012. This study suggests that accurate forecasting of road traffic death incidence is possible using SARIMA model. The SARIMA model applied to historical road traffic deaths data could provide important evidence of burden of road traffic injuries in China. Copyright © 2015 Elsevier Inc. All rights reserved.

PRECOG: a tool for automated extraction and visualization of fitness components in microbial growth phenomics.

PubMed

Fernandez-Ricaud, Luciano; Kourtchenko, Olga; Zackrisson, Martin; Warringer, Jonas; Blomberg, Anders

2016-06-23

Phenomics is a field in functional genomics that records variation in organismal phenotypes in the genetic, epigenetic or environmental context at a massive scale. For microbes, the key phenotype is the growth in population size because it contains information that is directly linked to fitness. Due to technical innovations and extensive automation our capacity to record complex and dynamic microbial growth data is rapidly outpacing our capacity to dissect and visualize this data and extract the fitness components it contains, hampering progress in all fields of microbiology. To automate visualization, analysis and exploration of complex and highly resolved microbial growth data as well as standardized extraction of the fitness components it contains, we developed the software PRECOG (PREsentation and Characterization Of Growth-data). PRECOG allows the user to quality control, interact with and evaluate microbial growth data with ease, speed and accuracy, also in cases of non-standard growth dynamics. Quality indices filter high- from low-quality growth experiments, reducing false positives. The pre-processing filters in PRECOG are computationally inexpensive and yet functionally comparable to more complex neural network procedures. We provide examples where data calibration, project design and feature extraction methodologies have a clear impact on the estimated growth traits, emphasising the need for proper standardization in data analysis. PRECOG is a tool that streamlines growth data pre-processing, phenotypic trait extraction, visualization, distribution and the creation of vast and informative phenomics databases.

Aerobic fitness and executive control of relational memory in preadolescent children.

PubMed

Chaddock, Laura; Hillman, Charles H; Buck, Sarah M; Cohen, Neal J

2011-02-01

the neurocognitive benefits of an active lifestyle in childhood have public health and educational implications, especially as children in today's technological society are becoming increasingly overweight, unhealthy, and unfit. Human and animal studies show that aerobic exercise affects both prefrontal executive control and hippocampal function. This investigation attempts to bridge these research threads by using a cognitive task to examine the relationship between aerobic fitness and executive control of relational memory in preadolescent 9- and 10-yr-old children. higher-fit and lower-fit children studied faces and houses under individual item (i.e., nonrelational) and relational encoding conditions, and the children were subsequently tested with recognition memory trials consisting of previously studied pairs and pairs of completely new items. With each subject participating in both item and relational encoding conditions, and with recognition test trials amenable to the use of both item and relational memory cues, this task afforded a challenge to the flexible use of memory, specifically in the use of appropriate encoding and retrieval strategies. Hence, the task provided a test of both executive control and memory processes. lower-fit children showed poorer recognition memory performance than higher-fit children, selectively in the relational encoding condition. No association between aerobic fitness and recognition performance was found for faces and houses studied as individual items (i.e., nonrelationally). the findings implicate childhood aerobic fitness as a factor in the ability to use effective encoding and retrieval executive control processes for relational memory material and, possibly, in the strategic engagement of prefrontal- and hippocampal-dependent systems.

Thermodynamic States in Explosion Fields

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

Kuhl, A L

2009-10-16

Here we investigate the thermodynamic states occurring in explosion fields from the detonation of condensed explosives in air. In typical applications, the pressure of expanded detonation products gases is modeled by a Jones-Wilkins-Lee (JWL) function: P{sub JWL} = f(v,s{sub CJ}); constants in that function are fit to cylinder test data. This function provides a specification of pressure as a function of specific volume, v, along the expansion isentrope (s = constant = s{sub CJ}) starting at the Chapman-Jouguet (CJ) state. However, the JWL function is not a fundamental equation of thermodynamics, and therefore gives an incomplete specification of states. Formore » example, explosions inherently involve shock reflections from surfaces; this changes the entropy of the products, and in such situations the JWL function provides no information on the products states. In addition, most explosives are not oxygen balanced, so if hot detonation products mix with air, they after-burn, releasing the heat of reaction via a turbulent combustion process. This raises the temperature of explosion products cloud to the adiabatic flame temperature ({approx}3,000K). Again, the JWL function provides no information on the combustion products states.« less

Developing an assessment based on physical fitness age to evaluate motor function in frail and healthy elderly women

PubMed Central

Nakagaichi, Masaki; Anan, Yuya; Hikiji, Yuto; Uratani, Sou

2018-01-01

Objectives The purpose of this study was to identify a method for assessing physical fitness age that is easy to use with both frail and healthy elderly women and to examine its validity. Methods Principal component analysis was used to develop a formula of physical fitness age from four motor function variables. The subjects comprised 688 (75.7±6.0 years) elderly women, in order to develop a physical fitness scale. The formula for calculating physical fitness age was expressed as physical fitness age =−0.419× grip strength −0.096× balancing on one leg with eyes open −0.737×30 s chair stand +0.503× figure-of-8 walking test +0.47× chronological age +52.68. Results Measures obtained from subjects in the frail elderly (n=11, 73.0±2.3 years) and exercise (n=10, 70.8±3.1 years) groups were used to examine the validity of the assessment. The mean physical fitness age of the frail elderly group (79.0±3.7 years) was significantly higher than its mean chronological age (73.0±2.3 years, p<0.05). The mean physical fitness age of the exercise group (65.6±3.1 years) was significantly lower than the chronological age (70.8±3.1 years, p<0.05). Conclusion These findings confirm that physical fitness age scores are applicable to frail and healthy elderly women. Physical fitness age is a valid measure of motor function in elderly women. PMID:29416326

Developing an assessment based on physical fitness age to evaluate motor function in frail and healthy elderly women.

PubMed

Nakagaichi, Masaki; Anan, Yuya; Hikiji, Yuto; Uratani, Sou

2018-01-01

The purpose of this study was to identify a method for assessing physical fitness age that is easy to use with both frail and healthy elderly women and to examine its validity. Principal component analysis was used to develop a formula of physical fitness age from four motor function variables. The subjects comprised 688 (75.7±6.0 years) elderly women, in order to develop a physical fitness scale. The formula for calculating physical fitness age was expressed as physical fitness age =-0.419× grip strength -0.096× balancing on one leg with eyes open -0.737×30 s chair stand +0.503× figure-of-8 walking test +0.47× chronological age +52.68. Measures obtained from subjects in the frail elderly (n=11, 73.0±2.3 years) and exercise (n=10, 70.8±3.1 years) groups were used to examine the validity of the assessment. The mean physical fitness age of the frail elderly group (79.0±3.7 years) was significantly higher than its mean chronological age (73.0±2.3 years, p <0.05). The mean physical fitness age of the exercise group (65.6±3.1 years) was significantly lower than the chronological age (70.8±3.1 years, p <0.05). These findings confirm that physical fitness age scores are applicable to frail and healthy elderly women. Physical fitness age is a valid measure of motor function in elderly women.

FIT: Computer Program that Interactively Determines Polynomial Equations for Data which are a Function of Two Independent Variables

NASA Technical Reports Server (NTRS)

Arbuckle, P. D.; Sliwa, S. M.; Roy, M. L.; Tiffany, S. H.

1985-01-01

A computer program for interactively developing least-squares polynomial equations to fit user-supplied data is described. The program is characterized by the ability to compute the polynomial equations of a surface fit through data that are a function of two independent variables. The program utilizes the Langley Research Center graphics packages to display polynomial equation curves and data points, facilitating a qualitative evaluation of the effectiveness of the fit. An explanation of the fundamental principles and features of the program, as well as sample input and corresponding output, are included.

Analytical fitting model for rough-surface BRDF.

PubMed

Renhorn, Ingmar G E; Boreman, Glenn D

2008-08-18

A physics-based model is developed for rough surface BRDF, taking into account angles of incidence and scattering, effective index, surface autocovariance, and correlation length. Shadowing is introduced on surface correlation length and reflectance. Separate terms are included for surface scatter, bulk scatter and retroreflection. Using the FindFit function in Mathematica, the functional form is fitted to BRDF measurements over a wide range of incident angles. The model has fourteen fitting parameters; once these are fixed, the model accurately describes scattering data over two orders of magnitude in BRDF without further adjustment. The resulting analytical model is convenient for numerical computations.

Functional models for colloid retention in porous media at the triple line.

PubMed

Dathe, Annette; Zevi, Yuniati; Richards, Brian K; Gao, Bin; Parlange, J-Yves; Steenhuis, Tammo S

2014-01-01

Spectral confocal microscope visualizations of microsphere movement in unsaturated porous media showed that attachment at the Air Water Solid (AWS) interface was an important retention mechanism. These visualizations can aid in resolving the functional form of retention rates of colloids at the AWS interface. In this study, soil adsorption isotherm equations were adapted by replacing the chemical concentration in the water as independent variable by the cumulative colloids passing by. In order of increasing number of fitted parameters, the functions tested were the Langmuir adsorption isotherm, the Logistic distribution, and the Weibull distribution. The functions were fitted against colloid concentrations obtained from time series of images acquired with a spectral confocal microscope for three experiments performed where either plain or carboxylated polystyrene latex microspheres were pulsed in a small flow chamber filled with cleaned quartz sand. Both moving and retained colloids were quantified over time. In fitting the models to the data, the agreement improved with increasing number of model parameters. The Weibull distribution gave overall the best fit. The logistic distribution did not fit the initial retention of microspheres well but otherwise the fit was good. The Langmuir isotherm only fitted the longest time series well. The results can be explained that initially when colloids are first introduced the rate of retention is low. Once colloids are at the AWS interface they act as anchor point for other colloids to attach and thereby increasing the retention rate as clusters form. Once the available attachment sites diminish, the retention rate decreases.

An investigation of the relationship between physical fitness, self-concept, and sexual functioning.

PubMed

Jiannine, Lia M

2018-01-01

Obesity and inactivity have led to an increasing number of individuals with sexual dysfunctions (43% of women; 31% of men). Small bouts of exercise can drastically improve sexual functioning. Thus, the present study is designed to examine the effects of physical fitness and self-concept on sexual functioning. Fitness assessments and questionnaires were administered to 133 participants between the ages of 18 and 50 years. Physical fitness was assessed through body composition, cardiovascular endurance, muscular strength, and muscular endurance. Self-concept was presented as a total self-concept score and as six individual concepts of self. Sexual function was presented as both an aggregate score and five separate constructs of sexual functioning - fantasy/cognition, arousal, orgasm, behavior/experience, and drive/desire. The results indicated that sexual behavior/experience was predicted by body fat percentage. In men, fantasy was related to total self-concept; sexual behavior/experience was related to likeability. In women, arousal was predicted by cardiovascular endurance. Total self-concept was related to both orgasm and sex drive/desire. Power and muscular strength were significantly related to number of sexual partners in women but not men. The present study adds to the growing body of evidence indicating a positive relationship between physical fitness and sexual health. Individuals with sexual dysfunctions, particularly women, who are not persuaded by the currently publicized benefits of physical activity, may be inclined to exercise to improve sexual functioning.

Optimal atomic structure of amorphous silicon obtained from density functional theory calculations

NASA Astrophysics Data System (ADS)

Pedersen, Andreas; Pizzagalli, Laurent; Jónsson, Hannes

2017-06-01

Atomic structure of amorphous silicon consistent with several reported experimental measurements has been obtained from annealing simulations using electron density functional theory calculations and a systematic removal of weakly bound atoms. The excess energy and density with respect to the crystal are well reproduced in addition to radial distribution function, angular distribution functions, and vibrational density of states. No atom in the optimal configuration is locally in a crystalline environment as deduced by ring analysis and common neighbor analysis, but coordination defects are present at a level of 1%-2%. The simulated samples provide structural models of this archetypal disordered covalent material without preconceived notion of the atomic ordering or fitting to experimental data.

Correction for isotopic interferences between analyte and internal standard in quantitative mass spectrometry by a nonlinear calibration function.

PubMed

Rule, Geoffrey S; Clark, Zlatuse D; Yue, Bingfang; Rockwood, Alan L

2013-04-16

Stable isotope-labeled internal standards are of great utility in providing accurate quantitation in mass spectrometry (MS). An implicit assumption has been that there is no "cross talk" between signals of the internal standard and the target analyte. In some cases, however, naturally occurring isotopes of the analyte do contribute to the signal of the internal standard. This phenomenon becomes more pronounced for isotopically rich compounds, such as those containing sulfur, chlorine, or bromine, higher molecular weight compounds, and those at high analyte/internal standard concentration ratio. This can create nonlinear calibration behavior that may bias quantitative results. Here, we propose the use of a nonlinear but more accurate fitting of data for these situations that incorporates one or two constants determined experimentally for each analyte/internal standard combination and an adjustable calibration parameter. This fitting provides more accurate quantitation in MS-based assays where contributions from analyte to stable labeled internal standard signal exist. It can also correct for the reverse situation where an analyte is present in the internal standard as an impurity. The practical utility of this approach is described, and by using experimental data, the approach is compared to alternative fits.

A robust and fast active contour model for image segmentation with intensity inhomogeneity

NASA Astrophysics Data System (ADS)

Ding, Keyan; Weng, Guirong

2018-04-01

In this paper, a robust and fast active contour model is proposed for image segmentation in the presence of intensity inhomogeneity. By introducing the local image intensities fitting functions before the evolution of curve, the proposed model can effectively segment images with intensity inhomogeneity. And the computation cost is low because the fitting functions do not need to be updated in each iteration. Experiments have shown that the proposed model has a higher segmentation efficiency compared to some well-known active contour models based on local region fitting energy. In addition, the proposed model is robust to initialization, which allows the initial level set function to be a small constant function.

Aerobic Fitness Thresholds Associated with Fifth Grade Academic Achievement

ERIC Educational Resources Information Center

Wittberg, Richard; Cottrell, Lesley A.; Davis, Catherine L.; Northrup, Karen L.

2010-01-01

Background: Whereas effects of physical fitness and physical activity on cognitive function have been documented, little is known about how they are related. Purpose: This study assessed student aerobic fitness measured by FITNESSGRAM Mile times and/or Pacer circuits and whether the nature of the association between aerobic fitness and…

Mating System Evolution under Strong Pollen Limitation: Evidence of Disruptive Selection through Male and Female Fitness in Clarkia xantiana.

PubMed

Briscoe Runquist, Ryan D; Geber, Monica A; Pickett-Leonard, Michael; Moeller, David A

2017-05-01

Selection on floral traits in hermaphroditic plants is determined by both male and female reproductive success. However, predictions regarding floral trait and mating system evolution are often based solely on female fitness. Selection via male fitness has the potential to affect the outcomes of floral evolution. In this study, we used paternity analysis to assess individual selfing rates and selection on floral traits via male and female fitness in an experimental population of Clarkia xantiana where pollen limitation of seed set was strong. We detected selection through both female and male fitness with reinforcing or noninterfering patterns of selection through the two sex functions. For female fitness, selection favored reduced herkogamy and protandry, traits that promote increased autonomous selfing. For male fitness, selection on petal area was disruptive, with higher trait values conferring greater pollinator attraction and outcross siring success and smaller trait values leading to higher selfed siring success. Combining both female and male fitness, selection on petal area and protandry was disruptive because intermediate phenotypes were less successful as both males and females. Finally, functional relationships among male and female fertility components indicated that selfing resulted in seed discounting and pollen discounting. Under these functional relationships, the evolutionarily stable selfing rate can be intermediate or predominantly selfing or outcrossing, depending on the segregating load of deleterious mutations.

Alternative Loglinear Smoothing Models and Their Effect on Equating Function Accuracy. Research Report. ETS RR-09-48

ERIC Educational Resources Information Center

Moses, Tim; Holland, Paul

2009-01-01

This simulation study evaluated the potential of alternative loglinear smoothing strategies for improving equipercentile equating function accuracy. These alternative strategies use cues from the sample data to make automatable and efficient improvements to model fit, either through the use of indicator functions for fitting large residuals or by…

First State Fitness Test. A Measurement of Functional Health.

ERIC Educational Resources Information Center

Brown, Timothy; And Others

This test is designed to measure the functional health of young people. Functional health refers to those factors relating to personal health that can be improved with regular exercise. This test is unique in comparison to other physical fitness tests because of the absence of motor skill items which have no relationship to an individual's…

Training Status as a Marker of the Relationship between Nitric Oxide, Oxidative Stress, and Blood Pressure in Older Adult Women

PubMed Central

Mourão Jacomini, André; Celso Dutra de Souza, Hugo; da Silva Dias, Danielle; de Oliveira Brito, Janaina; Cezar Pinheiro, Lucas; Bernardino da Silva, Anderson; Fernanda da Silva, Roberta; Alexandre Trapé, Atila; De Angelis, Kátia; Tanus-Santos, José Eduardo; Lia do Amaral, Sandra; Saranz Zago, Anderson

2016-01-01

The purpose of this study was to evaluate the influence of functional fitness and oxidative capacity on the nitric oxide concentration associated with hemodynamic control in older adult women. The sample consisted of 134 women (65.73 ± 6.14 years old). All subjects underwent a physical examination to assess body mass index, waist-hip ratio, body fat measurement by dual energy X-ray absorptiometry, and blood pressure (BP). Training status (TS) was evaluated by indirect determination of maximal oxygen uptake by a treadmill test using Balke protocol modified for older adults. Functional fitness was also evaluated through a “Functional Fitness Battery Test” to determine the general fitness functional index (GFFI). All participants were separated according to the functional fitness (TS1, very weak and weak; TS2, regular; TS3, good and very good). Plasma blood samples were used to evaluate prooxidant and antioxidant activity and nitrite and nitrate concentrations. The general results of this study showed that good levels of TS were related to lower levels of lipoperoxidation and protein damage, higher levels of antioxidant, and higher concentration of nitrite and nitrate. This combination may be responsible for the lower levels of BP in subjects with better TS. PMID:26697141

Training Status as a Marker of the Relationship between Nitric Oxide, Oxidative Stress, and Blood Pressure in Older Adult Women.

PubMed

Jacomini, André Mourão; de Souza, Hugo Celso Dutra; Dias, Danielle da Silva; Brito, Janaina de Oliveira; Pinheiro, Lucas Cezar; da Silva, Anderson Bernardino; da Silva, Roberta Fernanda; Trapé, Atila Alexandre; De Angelis, Kátia; Tanus-Santos, José Eduardo; do Amaral, Sandra Lia; Zago, Anderson Saranz

2015-01-01

The purpose of this study was to evaluate the influence of functional fitness and oxidative capacity on the nitric oxide concentration associated with hemodynamic control in older adult women. The sample consisted of 134 women (65.73 ± 6.14 years old). All subjects underwent a physical examination to assess body mass index, waist-hip ratio, body fat measurement by dual energy X-ray absorptiometry, and blood pressure (BP). Training status (TS) was evaluated by indirect determination of maximal oxygen uptake by a treadmill test using Balke protocol modified for older adults. Functional fitness was also evaluated through a "Functional Fitness Battery Test" to determine the general fitness functional index (GFFI). All participants were separated according to the functional fitness (TS1, very weak and weak; TS2, regular; TS3, good and very good). Plasma blood samples were used to evaluate prooxidant and antioxidant activity and nitrite and nitrate concentrations. The general results of this study showed that good levels of TS were related to lower levels of lipoperoxidation and protein damage, higher levels of antioxidant, and higher concentration of nitrite and nitrate. This combination may be responsible for the lower levels of BP in subjects with better TS.

Trait-fitness relationships determine how trade-off shapes affect species coexistence.

PubMed

Ehrlich, Elias; Becks, Lutz; Gaedke, Ursula

2017-12-01

Trade-offs between functional traits are ubiquitous in nature and can promote species coexistence depending on their shape. Classic theory predicts that convex trade-offs facilitate coexistence of specialized species with extreme trait values (extreme species) while concave trade-offs promote species with intermediate trait values (intermediate species). We show here that this prediction becomes insufficient when the traits translate non-linearly into fitness which frequently occurs in nature, e.g., an increasing length of spines reduces grazing losses only up to a certain threshold resulting in a saturating or sigmoid trait-fitness function. We present a novel, general approach to evaluate the effect of different trade-off shapes on species coexistence. We compare the trade-off curve to the invasion boundary of an intermediate species invading the two extreme species. At this boundary, the invasion fitness is zero. Thus, it separates trait combinations where invasion is or is not possible. The invasion boundary is calculated based on measurable trait-fitness relationships. If at least one of these relationships is not linear, the invasion boundary becomes non-linear, implying that convex and concave trade-offs not necessarily lead to different coexistence patterns. Therefore, we suggest a new ecological classification of trade-offs into extreme-favoring and intermediate-favoring which differs from a purely mathematical description of their shape. We apply our approach to a well-established model of an empirical predator-prey system with competing prey types facing a trade-off between edibility and half-saturation constant for nutrient uptake. We show that the survival of the intermediate prey depends on the convexity of the trade-off. Overall, our approach provides a general tool to make a priori predictions on the outcome of competition among species facing a common trade-off in dependence of the shape of the trade-off and the shape of the trait-fitness relationships. © 2017 by the Ecological Society of America.

Prevalence of falls in elderly women

PubMed Central

Vitor, Priscila Regina Rorato; de Oliveira, Ana Carolina Kovaleski; Kohler, Renan; Winter, Gabriele Regiane; Rodacki, Cintia; Krause, Maressa Priscila

2015-01-01

OBJECTIVE: To verify prevalence of falls and fear of falling, and to compare functional fitness among elderly women fallers and non-fallers. METHODS: Seventy-eight elderly women participated in this study. Cases of falls and the fear of falling were self-reported by the elderly women, while the functional fitness was measured by a set of functional tests. Mean and standard deviation were used to describe the sample. Independent t-test was used to compare functional fitness between groups. RESULTS: The prevalence of falls in this sample was 32.4%. Among women fallers, 40% self-reported a high fear of falling. CONCLUSION: It is recommended that functional and resistance exercises are included in the preventive strategies for reducing risk factors for falls and its determinants in elderly women. Level of Evidence II, Prognostic-Prospective Study. PMID:26207095

Family involvement in the psychological treatment of obsessive-compulsive disorder: A meta-analysis

PubMed Central

Thompson-Hollands, Johanna; Edson, Aubrey; Tompson, Martha C.; Comer, Jonathan S.

2014-01-01

Psychological treatments for OCD are increasingly aimed at improving outcomes by directly incorporating family members to address family disruption, dysfunction, or symptom accommodation. Much remains to be learned about the pooled effects of “family-inclusive treatment” (FIT) for OCD and factors that may explain variation in response. Random-effects meta-analytic procedures were conducted to empirically evaluate the overall effect of FITs on OCD, and treatment moderators. Study search criteria yielded 29 studies examining FIT response in 1,366 OCD patients. Outcome variables included OCD symptoms and global functioning. Examined moderators included age group, gender, minority status, treatment length and format, and inclusion of specific family-focused treatment elements. FITs for OCD demonstrated a large overall effect on OCD symptoms (pooled d = 1.68, SE = 0.14) and global functioning (pooled d = 0.98, SE = 0.14). Moderator analyses found that individual family treatments (versus group) and FITs targeting family accommodation of symptoms (versus those that did not target accommodation) were associated with greater improvements in patient functioning. Results indicate a robust overall response to FITs for OCD and clarify key moderators that inform optimal circumstances for effective treatment. Findings underscore the need for continued momentum in the development, evaluation, and dissemination of FITs for OCD. PMID:24798816

How do cardiorespiratory fitness improvements vary with physical training modality in heart failure patients? A quantitative guide

PubMed Central

Smart, Neil A

2013-01-01

BACKGROUND: Peak oxygen consumption (VO2) is the gold standard measure of cardiorespiratory fitness and a reliable predictor of survival in chronic heart failure patients. Furthermore, any form of physical training usually improves cardiorespiratory fitness, although the magnitude of improvement in peak VO2 may vary across different training prescriptions. OBJECTIVE: To quantify, and subsequently rank, the magnitude of improvement in peak VO2 for different physical training prescriptions using data from published meta-analyses and randomized controlled trials. METHODS: Prospective randomized controlled parallel trials and meta-analyses of exercise training in chronic heart failure patients that provided data on change in peak VO2 for nine a priori comparative analyses were examined. RESULTS: All forms of physical training were beneficial, although the improvement in peak VO2 varied with modality. High-intensity interval exercise yielded the largest increase in peak VO2, followed in descending order by moderate-intensity aerobic exercise, functional electrical stimulation, inspiratory muscle training, combined aerobic and resistance training, and isolated resistance training. With regard to setting, the present study was unable to determine whether outpatient or unsupervised home exercise provided greater benefits in terms of peak VO2 improvment. CONCLUSIONS: Interval exercise is not suitable for all patients, especially the high-intensity variety; however, when indicated, this form of exercise should be adopted to optimize peak VO2 adaptations. Other forms of activity, such as functional electrical stimulation, may be more appropriate for patients who are not capable of high-intensity interval training, especially for severely deconditioned patients who are initially unable to exercise. PMID:24294043

Diffractive ρ and ϕ production at HERA using a holographic AdS/QCD light-front meson wave function

NASA Astrophysics Data System (ADS)

Ahmady, Mohammad; Sandapen, Ruben; Sharma, Neetika

2016-10-01

We use an anti-de Sitter/quantum chromodynamics holographic light-front wave function for the ρ and ϕ mesons, in conjunction with the color glass condensate dipole cross section whose parameters are fitted to the most recent 2015 high precision HERA data on inclusive deep inelastic scattering, in order to predict the cross sections for diffractive ρ and ϕ electroproduction. Our results suggest that the holographic meson light-front wave function is able to give a simultaneous description of ρ and ϕ production data provided we use a set of light quark masses with mu ,d

Evidence-Based Annotation of Gene Function in Shewanella oneidensis MR-1 Using Genome-Wide Fitness Profiling across 121 Conditions

PubMed Central

Deutschbauer, Adam; Price, Morgan N.; Wetmore, Kelly M.; Shao, Wenjun; Baumohl, Jason K.; Xu, Zhuchen; Nguyen, Michelle; Tamse, Raquel; Davis, Ronald W.; Arkin, Adam P.

2011-01-01

Most genes in bacteria are experimentally uncharacterized and cannot be annotated with a specific function. Given the great diversity of bacteria and the ease of genome sequencing, high-throughput approaches to identify gene function experimentally are needed. Here, we use pools of tagged transposon mutants in the metal-reducing bacterium Shewanella oneidensis MR-1 to probe the mutant fitness of 3,355 genes in 121 diverse conditions including different growth substrates, alternative electron acceptors, stresses, and motility. We find that 2,350 genes have a pattern of fitness that is significantly different from random and 1,230 of these genes (37% of our total assayed genes) have enough signal to show strong biological correlations. We find that genes in all functional categories have phenotypes, including hundreds of hypotheticals, and that potentially redundant genes (over 50% amino acid identity to another gene in the genome) are also likely to have distinct phenotypes. Using fitness patterns, we were able to propose specific molecular functions for 40 genes or operons that lacked specific annotations or had incomplete annotations. In one example, we demonstrate that the previously hypothetical gene SO_3749 encodes a functional acetylornithine deacetylase, thus filling a missing step in S. oneidensis metabolism. Additionally, we demonstrate that the orphan histidine kinase SO_2742 and orphan response regulator SO_2648 form a signal transduction pathway that activates expression of acetyl-CoA synthase and is required for S. oneidensis to grow on acetate as a carbon source. Lastly, we demonstrate that gene expression and mutant fitness are poorly correlated and that mutant fitness generates more confident predictions of gene function than does gene expression. The approach described here can be applied generally to create large-scale gene-phenotype maps for evidence-based annotation of gene function in prokaryotes. PMID:22125499

Interventions to evaluate fitness to drive among people with chronic conditions: Systematic review of literature.

PubMed

Marino, Marta; de Belvis, Antonio; Basso, Danila; Avolio, Maria; Pelone, Ferruccio; Tanzariello, Maria; Ricciardi, Walter

2013-01-01

When an health condition has been identified, the question of whether to continue driving depends not on a medical diagnosis, but on the functional consequences of the illness. The complex nature of physical and mental impairments and their relationship with safe driving make the availability of evidence based tools necessary for health professionals. The review aims at identifying and summarizing scientific findings concerning the relationship between neuropsychological and clinical screening tests and fitness to drive among people with chronic conditions. Studies were searched for driving ability evaluation by road test or simulator, clinical/neuropsychological examinations of participants with chronic diseases or permanent disablement impairing driving performance, primary outcomes as fatal/non-fatal traffic injuries and secondary outcomes as fitness to drive assessment. Twenty-seven studies fulfilled the inclusion criteria. Some studies included more than one clinical condition. The illness investigated were Alzheimer Disease (n=6), Parkinson Disease (n=8), Cardiovascular Accident (n=4), Traumatic Brain Injuries (n=3), Sleep Apnea Syndrome (n=2), Narcolepsy (n=1), Multiple Sclerosis (n=1) and Hepatic Encephalopathy (n=1), comorbidities (n=3). No studies match inclusion criteria about Myasthenia Gravis, Diabetes Mellitus, Renal Diseases, Hearing Disorders and Sight Diseases. No studies referred to primary outcomes. The selected studies provided opposite evidences. It would be reasonable to argue that some clinical and neuropsychological tests are effective in predicting fitness to drive even if contrasting results support that driving performance decreases as a function of clinical and neuropsychological decline in some chronic diseases. Nevertheless we found no evidence that clinical and neuropsychological screening tests would lead to a reduction in motor vehicle crashes involving chronic disabled drivers. It seems necessary to develop tests with proven validity for identifying high-risk drivers so that physicians can provide guidance to their patients in chronic conditions, and also to medical advisory boards working with licensing offices. Copyright © 2012 Elsevier Ltd. All rights reserved.

Investigating different approaches to develop informative priors in hierarchical Bayesian safety performance functions.

PubMed

Yu, Rongjie; Abdel-Aty, Mohamed

2013-07-01

The Bayesian inference method has been frequently adopted to develop safety performance functions. One advantage of the Bayesian inference is that prior information for the independent variables can be included in the inference procedures. However, there are few studies that discussed how to formulate informative priors for the independent variables and evaluated the effects of incorporating informative priors in developing safety performance functions. This paper addresses this deficiency by introducing four approaches of developing informative priors for the independent variables based on historical data and expert experience. Merits of these informative priors have been tested along with two types of Bayesian hierarchical models (Poisson-gamma and Poisson-lognormal models). Deviance information criterion (DIC), R-square values, and coefficients of variance for the estimations were utilized as evaluation measures to select the best model(s). Comparison across the models indicated that the Poisson-gamma model is superior with a better model fit and it is much more robust with the informative priors. Moreover, the two-stage Bayesian updating informative priors provided the best goodness-of-fit and coefficient estimation accuracies. Furthermore, informative priors for the inverse dispersion parameter have also been introduced and tested. Different types of informative priors' effects on the model estimations and goodness-of-fit have been compared and concluded. Finally, based on the results, recommendations for future research topics and study applications have been made. Copyright © 2013 Elsevier Ltd. All rights reserved.

A Protocol for Functional Assessment of Whole-Protein Saturation Mutagenesis Libraries Utilizing High-Throughput Sequencing.

PubMed

Stiffler, Michael A; Subramanian, Subu K; Salinas, Victor H; Ranganathan, Rama

2016-07-03

Site-directed mutagenesis has long been used as a method to interrogate protein structure, function and evolution. Recent advances in massively-parallel sequencing technology have opened up the possibility of assessing the functional or fitness effects of large numbers of mutations simultaneously. Here, we present a protocol for experimentally determining the effects of all possible single amino acid mutations in a protein of interest utilizing high-throughput sequencing technology, using the 263 amino acid antibiotic resistance enzyme TEM-1 β-lactamase as an example. In this approach, a whole-protein saturation mutagenesis library is constructed by site-directed mutagenic PCR, randomizing each position individually to all possible amino acids. The library is then transformed into bacteria, and selected for the ability to confer resistance to β-lactam antibiotics. The fitness effect of each mutation is then determined by deep sequencing of the library before and after selection. Importantly, this protocol introduces methods which maximize sequencing read depth and permit the simultaneous selection of the entire mutation library, by mixing adjacent positions into groups of length accommodated by high-throughput sequencing read length and utilizing orthogonal primers to barcode each group. Representative results using this protocol are provided by assessing the fitness effects of all single amino acid mutations in TEM-1 at a clinically relevant dosage of ampicillin. The method should be easily extendable to other proteins for which a high-throughput selection assay is in place.

On the Specification of Upward-Propagating Tides for ICON Science Investigations

NASA Astrophysics Data System (ADS)

Forbes, Jeffrey M.; Zhang, Xiaoli; Hagan, Maura E.; England, Scott L.; Liu, Guiping; Gasperini, Federico

2017-10-01

The National Center for Atmospheric Research (NCAR) Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) will provide a physics-based context for the interpretation of ICON measurements. To optimize the realism of the model simulations, ICON wind and temperature measurements near the ˜97 km lower boundary of the TIEGCM will be used to specify the upward-propagating tidal spectrum at this altitude. This will be done by fitting a set of basis functions called Hough Mode Extensions (HMEs) to 27-day mean tidal winds and temperatures between 90 and 105 km altitude and between 12 °S and 42 °N latitude on a day-by-day basis. The current paper assesses the veracity of the HME fitting methodology given the restricted latitude sampling and the UT-longitude sampling afforded by the MIGHTI instrument viewing from the ICON satellite, which will be in a circular 27° inclination orbit. These issues are investigated using the output from a reanalysis-driven global circulation model, which contains realistic variability of the important tidal components, as a mock data set. ICON sampling of the model reveals that the 27-day mean diurnal and semidiurnal tidal components replicate well the 27-day mean tidal components obtained from full synoptic sampling of the model, but the terdiurnal tidal components are not faithfully reproduced. It is also demonstrated that reconstructed tidal components based on HME fitting to the model tides between 12 °S and 42 °N latitude provide good approximations to the major tidal components expected to be encountered during the ICON mission. This is because the constraints provided by fitting both winds and temperatures over the 90-105 km height range are adequate to offset the restricted sampling in latitude. The boundary conditions provided by the methodology described herein will greatly enhance the ability of the TIEGCM to provide a physical framework for interpreting atmosphere-ionosphere coupling in ICON observations due to atmospheric tides.

Estimating metallicities with isochrone fits to photometric data of open clusters

NASA Astrophysics Data System (ADS)

Monteiro, H.; Oliveira, A. F.; Dias, W. S.; Caetano, T. C.

2014-10-01

The metallicity is a critical parameter that affects the correct determination of stellar cluster's fundamental characteristics and has important implications in Galactic and Stellar evolution research. Fewer than 10% of the 2174 currently catalogued open clusters have their metallicity determined in the literature. In this work we present a method for estimating the metallicity of open clusters via non-subjective isochrone fitting using the cross-entropy global optimization algorithm applied to UBV photometric data. The free parameters distance, reddening, age, and metallicity are simultaneously determined by the fitting method. The fitting procedure uses weights for the observational data based on the estimation of membership likelihood for each star, which considers the observational magnitude limit, the density profile of stars as a function of radius from the center of the cluster, and the density of stars in multi-dimensional magnitude space. We present results of [Fe/H] for well-studied open clusters based on distinct UBV data sets. The [Fe/H] values obtained in the ten cases for which spectroscopic determinations were available in the literature agree, indicating that our method provides a good alternative to estimating [Fe/H] by using an objective isochrone fitting. Our results show that the typical precision is about 0.1 dex.

Auditory fitness for duty: a review.

PubMed

Tufts, Jennifer B; Vasil, Kristin A; Briggs, Sarah

2009-10-01

Auditory fitness for duty (AFFD) refers to the possession of hearing abilities sufficient for safe and effective job performance. In jobs such as law enforcement and piloting, where the ability to hear is critical to job performance and safety, hearing loss can decrease performance, even to the point of being hazardous to self and others. Tests of AFFD should provide an employer with a valid assessment of an employee's ability to perform the job safely, without discriminating against the employee purely on the basis of hearing loss. The purpose of this review is to provide a basic description of the functional hearing abilities required in hearing-critical occupations, and a summary of current practices in AFFD evaluation. In addition, we suggest directions for research and standardization to ensure best practices in the evaluation of AFFD in the future. We conducted a systematic review of the English-language peer-reviewed literature in AFFD. "Popular" search engines were consulted for governmental regulations and trade journal articles. We also contacted professionals with expertise in AFFD regarding research projects, unpublished material, and current standards. The literature review provided information regarding the functional hearing abilities required to perform hearing-critical tasks, the development of and characteristics of AFFD protocols, and the current implementation of AFFD protocols. This review paper provides evidence of the need to institute job-specific AFFD protocols, move beyond the pure-tone audiogram, and establish the validity of test protocols. These needs are arguably greater now than in times past.

New collinear twist-3 analysis of transverse SSA: Toward a resolution for the sign-mismatch problem

DOE PAGES

Kanazawa, Koichi; Pitonyak, Daniel; Koike, Yuji; ...

2014-10-19

We present a new collinear twist-3 analysis of the transverse SSA A N at RHIC. We use the TMD Sivers/Collins function to fix some of the relevant collinear twist-3 functions and perform a fit of the RHIC data with other parameterized twist-3 functions. This allows us to keep the consistency among descriptions in pp collision, SIDIS, and e +e – annihilation and thus could provide a unified description of the spin asymmetries in the low- and high-P T processes. In conclusion, by taking into account the twist-3 fragmentation contribution, we show for the first time this contribution could be themore » main source of A N in pp ↑ → hX and its inclusion could provide a solution for the sign-mismatch problem.« less

Space Shuttle avionics upgrade - Issues and opportunities

NASA Astrophysics Data System (ADS)

Swaim, Richard A.; Wingert, William B.

An overview is conducted of existing Space Shuttle avionics and the possibilities for upgrading the cockpit to reduce costs and increase functionability. The current avionics include five general-purpose computers fitted with multifunction displays, dedicated switches and indicators, and dedicated flight instruments. The operational needs of the Shuttle are reviewed in the light of the avionics and potential upgrades in the form of microprocessors and display systems. The use of better processors can provide hardware support for multitasking and memory management and can reduce the life-cycle cost for software. Some limitations of the current technology are acknowledged including the Shuttle's power budget and structural configuration. A phased infusion of upgraded avionics is proposed that provides a functionally transparent replacement of crew-interface equipment as well as the addition of interface enhancements and the migration of selected functions.

Individual differences in long-range time representation.

PubMed

Agostino, Camila S; Caetano, Marcelo S; Balci, Fuat; Claessens, Peter M E; Zana, Yossi

2017-04-01

On the basis of experimental data, long-range time representation has been proposed to follow a highly compressed power function, which has been hypothesized to explain the time inconsistency found in financial discount rate preferences. The aim of this study was to evaluate how well linear and power function models explain empirical data from individual participants tested in different procedural settings. The line paradigm was used in five different procedural variations with 35 adult participants. Data aggregated over the participants showed that fitted linear functions explained more than 98% of the variance in all procedures. A linear regression fit also outperformed a power model fit for the aggregated data. An individual-participant-based analysis showed better fits of a linear model to the data of 14 participants; better fits of a power function with an exponent β > 1 to the data of 12 participants; and better fits of a power function with β < 1 to the data of the remaining nine participants. Of the 35 volunteers, the null hypothesis β = 1 was rejected for 20. The dispersion of the individual β values was approximated well by a normal distribution. These results suggest that, on average, humans perceive long-range time intervals not in a highly compressed, biased manner, but rather in a linear pattern. However, individuals differ considerably in their subjective time scales. This contribution sheds new light on the average and individual psychophysical functions of long-range time representation, and suggests that any attribution of deviation from exponential discount rates in intertemporal choice to the compressed nature of subjective time must entail the characterization of subjective time on an individual-participant basis.

Effects of Nintendo Wii Fit Plus training on ankle strength with functional ankle instability.

PubMed

Kim, Ki-Jong; Jun, Hyun-Ju; Heo, Myoung

2015-11-01

[Purpose] The objective of this study was to examine the effects of a training program using the Nintendo Wii Fit Plus on the ankle muscle strengths of subjects with functional ankle instability. [Subjects and Methods] This study was conducted using subjects in their 20s who had functional ankle instability. They were randomized to a strengthening training group and a balance training group with 10 subjects in each, and they performed an exercise using Nintendo Wii Fit Plus for 20 minutes. In addition, every participant completed preparation and finishing exercises for 5 minutes, respectively. [Results] The muscle strengths after conducting plantar flexion and dorsiflexion significantly increased at the angular velocities of 60° and 120° in the strengthening training group. Furthermore, the muscle strengths after conducting plantar flexion, dorsiflexion, eversion, and inversion significantly increased at the angular velocities of 60° and 120° in the balance training group. [Conclusion] The balance training group using Nintendo Wii Fit Plus showed better results than the strengthening training group. Consequently, it is recommended to add the balance training program of the Nintendo Wii Fit Plus to conventional exercise programs to improve ankle muscle strength in functional ankle instability at a low cost.

A systematic way for the cost reduction of density fitting methods

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

Kállay, Mihály, E-mail: kallay@mail.bme.hu

2014-12-28

We present a simple approach for the reduction of the size of auxiliary basis sets used in methods exploiting the density fitting (resolution of identity) approximation for electron repulsion integrals. Starting out of the singular value decomposition of three-center two-electron integrals, new auxiliary functions are constructed as linear combinations of the original fitting functions. The new functions, which we term natural auxiliary functions (NAFs), are analogous to the natural orbitals widely used for the cost reduction of correlation methods. The use of the NAF basis enables the systematic truncation of the fitting basis, and thereby potentially the reduction of themore » computational expenses of the methods, though the scaling with the system size is not altered. The performance of the new approach has been tested for several quantum chemical methods. It is demonstrated that the most pronounced gain in computational efficiency can be expected for iterative models which scale quadratically with the size of the fitting basis set, such as the direct random phase approximation. The approach also has the promise of accelerating local correlation methods, for which the processing of three-center Coulomb integrals is a bottleneck.« less

Basilar-membrane responses to broadband noise modeled using linear filters with rational transfer functions.

PubMed

Recio-Spinoso, Alberto; Fan, Yun-Hui; Ruggero, Mario A

2011-05-01

Basilar-membrane responses to white Gaussian noise were recorded using laser velocimetry at basal sites of the chinchilla cochlea with characteristic frequencies near 10 kHz and first-order Wiener kernels were computed by cross correlation of the stimuli and the responses. The presence or absence of minimum-phase behavior was explored by fitting the kernels with discrete linear filters with rational transfer functions. Excellent fits to the kernels were obtained with filters with transfer functions including zeroes located outside the unit circle, implying nonminimum-phase behavior. These filters accurately predicted basilar-membrane responses to other noise stimuli presented at the same level as the stimulus for the kernel computation. Fits with all-pole and other minimum-phase discrete filters were inferior to fits with nonminimum-phase filters. Minimum-phase functions predicted from the amplitude functions of the Wiener kernels by Hilbert transforms were different from the measured phase curves. These results, which suggest that basilar-membrane responses do not have the minimum-phase property, challenge the validity of models of cochlear processing, which incorporate minimum-phase behavior. © 2011 IEEE

QCD evolution of the Sivers function

NASA Astrophysics Data System (ADS)

Aybat, S. M.; Collins, J. C.; Qiu, J. W.; Rogers, T. C.

2012-02-01

We extend the Collins-Soper-Sterman (CSS) formalism to apply it to the spin dependence governed by the Sivers function. We use it to give a correct numerical QCD evolution of existing fixed-scale fits of the Sivers function. With the aid of approximations useful for the nonperturbative region, we present the results as parametrizations of a Gaussian form in transverse-momentum space, rather than in the Fourier conjugate transverse coordinate space normally used in the CSS formalism. They are specifically valid at small transverse momentum. Since evolution has been applied, our results can be used to make predictions for Drell-Yan and semi-inclusive deep inelastic scattering at energies different from those where the original fits were made. Our evolved functions are of a form that they can be used in the same parton-model factorization formulas as used in the original fits, but now with a predicted scale dependence in the fit parameters. We also present a method by which our evolved functions can be corrected to allow for twist-3 contributions at large parton transverse momentum.

Effects of customization on application decisions and applicant pool characteristics in a web-based recruitment context.

PubMed

Dineen, Brian R; Noe, Raymond A

2009-01-01

The authors examined 2 forms of customization in a Web-based recruitment context. Hypotheses were tested in a controlled study in which participants viewed multiple Web-based job postings that each included information about multiple fit categories. Results indicated that customization of information regarding person-organization (PO), needs-supplies, and demands-abilities (DA) fit (fit information customization) and customization of the order in which these fit categories were presented (configural customization) had differential effects on outcomes. Specifically, (a) applicant pool PO and DA fit were greater when fit information customization was provided, (b) applicant pool fit in high- versus low-relevance fit categories was better differentiated when configural customization was provided, and (c) overall application rates were lower when either or both forms of customization were provided. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

The relationship between sustained attention and aerobic fitness in a group of young adults.

PubMed

Ciria, Luis F; Perakakis, Pandelis; Luque-Casado, Antonio; Morato, Cristina; Sanabria, Daniel

2017-01-01

A growing set of studies has shown a positive relationship between aerobic fitness and a broad array of cognitive functions. However, few studies have focused on sustained attention, which has been considered a fundamental cognitive process that underlies most everyday activities. The purpose of this study was to investigate the role of aerobic fitness as a key factor in sustained attention capacities in young adults. Forty-four young adults (18-23 years) were divided into two groups as a function of the level of aerobic fitness (high-fit and low-fit). Participants completed the Psychomotor Vigilance Task (PVT) and an oddball task where they had to detect infrequent targets presented among frequent non-targets. The analysis of variance (ANOVA) showed faster responses for the high-fit group than for the low-fit group in the PVT, replicating previous accounts. In the oddball task, the high-fit group maintained their accuracy (ACC) rate of target detection over time, while the low-fit group suffered a significant decline of response ACC throughout the task. Importantly, the results show that the greater sustained attention capacity of high-fit young adults is not specific to a reaction time (RT) sustained attention task like the PVT, but it is also evident in an ACC oddball task. In sum, the present findings point to the important role of aerobic fitness on sustained attention capacities in young adults.

Simplified curve fits for the thermodynamic properties of equilibrium air

NASA Technical Reports Server (NTRS)

Srinivasan, S.; Tannehill, J. C.; Weilmuenster, K. J.

1986-01-01

New improved curve fits for the thermodynamic properties of equilibrium air were developed. The curve fits are for p = p(e,rho), a = a(e,rho), T = T(e,rho), s = s(e,rho), T = T(p,rho), h = h(p,rho), rho = rho(p,s), e = e(p,s) and a = a(p,s). These curve fits can be readily incorporated into new or existing Computational Fluid Dynamics (CFD) codes if real-gas effects are desired. The curve fits were constructed using Grabau-type transition functions to model the thermodynamic surfaces in a piecewise manner. The accuracies and continuity of these curve fits are substantially improved over those of previous curve fits appearing in NASA CR-2470. These improvements were due to the incorporation of a small number of additional terms in the approximating polynomials and careful choices of the transition functions. The ranges of validity of the new curve fits are temperatures up to 25,000 K and densities from 10 to the minus 7th to 100 amagats (rho/rho sub 0).

The evolution of X-ray clusters in a cold plus hot dark matter universe

NASA Technical Reports Server (NTRS)

Bryan, Greg L.; Klypin, Anatoly; Loken, Chris; Norman, Michael L.; Burns, Jack O.

1994-01-01

We present the first self-consistently computed results on the evolution of X-ray properties of galaxy clusters in a cold + hot dark matter (CHDM) model. We have performed a hydrodynamic plus N-body simulation for the COBE-compatible CHDM model with standard mass components: Omega(sub hot) = 0.3, Omega (sub cold) = 0.6 and Omega(sub baryon) = 0.1 (h = 0.5). In contrast with the CDM model, which fails to reproduce the observed temperature distribution function dN/dT (Bryan et al. 1994b), the CHDM model fits the observational dN/dT quite well. Our results on X-ray luminosity are less firm but even more intriguing. We find that the resulting X-ray luminosity functions at redshifts z = 0.0, 0.2, 0.4, 0.7 are well fit by observations, where they overlap. The fact that both temperatures and luminosities provide a reasonable fit to the available observational data indicates that, unless we are missing some essential physics, there is neither room nor need for a large fraction of gas in rich clusters: 10% (or less) in baryons is sufficient to explain their X-ray properties. We also see a tight correlation between X-ray luminosity and gas temperature.

Recommendations for fitness for work medical evaluations in chronic respiratory patients. Spanish Society of Pulmonology and Thoracic Surgery (SEPAR).

PubMed

Martínez González, Cristina; González Barcala, Francisco Javier; Belda Ramírez, José; González Ros, Isabel; Alfageme Michavila, Inmaculada; Orejas Martínez, Cristina; González Rodríguez-Moro, José Miguel; Rodríguez Portal, José Antonio; Fernández Álvarez, Ramón

2013-11-01

Chronic respiratory diseases often cause impairment in the functions and/or structure of the respiratory system, and impose limitations on different activities in the lives of persons who suffer them. In younger patients with an active working life, these limitations can cause problems in carrying out their normal work. Article 41 of the Spanish Constitution states that «the public authorities shall maintain a public Social Security system for all citizens guaranteeing adequate social assistance and benefits in situations of hardship». Within this framework is the assessment of fitness for work, as a dual-nature process (medico-legal) that aims to determine whether it is appropriate or not to recognise a person's right to receive benefits which replace the income that they no longer receive as they cannot carry out their work, due to loss of health. The role of the pulmonologist is essential in evaluating the diagnosis, treatment, prognosis and functional capacity of respiratory patients. These recommendations seek to bring the complex setting of fitness for work evaluation to pulmonologists and thoracic surgeons, providing action guidelines that allow them to advise their own patients about their incorporation into working life. Copyright © 2013 SEPAR. Published by Elsevier Espana. All rights reserved.

Extraction of object skeletons in multispectral imagery by the orthogonal regression fitting

NASA Astrophysics Data System (ADS)

Palenichka, Roman M.; Zaremba, Marek B.

2003-03-01

Accurate and automatic extraction of skeletal shape of objects of interest from satellite images provides an efficient solution to such image analysis tasks as object detection, object identification, and shape description. The problem of skeletal shape extraction can be effectively solved in three basic steps: intensity clustering (i.e. segmentation) of objects, extraction of a structural graph of the object shape, and refinement of structural graph by the orthogonal regression fitting. The objects of interest are segmented from the background by a clustering transformation of primary features (spectral components) with respect to each pixel. The structural graph is composed of connected skeleton vertices and represents the topology of the skeleton. In the general case, it is a quite rough piecewise-linear representation of object skeletons. The positions of skeleton vertices on the image plane are adjusted by means of the orthogonal regression fitting. It consists of changing positions of existing vertices according to the minimum of the mean orthogonal distances and, eventually, adding new vertices in-between if a given accuracy if not yet satisfied. Vertices of initial piecewise-linear skeletons are extracted by using a multi-scale image relevance function. The relevance function is an image local operator that has local maximums at the centers of the objects of interest.

Statistical assessment of optical phase fluctuations through turbulent mixing layers

NASA Astrophysics Data System (ADS)

Gardner, Patrick J.; Roggemann, Michael C.; Welsh, Byron M.; Bowersox, Rodney D.

1995-09-01

A lateral shearing interferometer is used to measure the slope of perturbed wavefronts after propagating through turbulent shear flows. This provides a two-dimensional flow visualization technique which is nonintrusive. The slope measurements are used to reconstruct the phase of the turbulence-corrupted wave front. Experiments were performed on a plane shear mixing layer of helium and nitrogen gas at fixed velocities, for five locations in the flow development. The two gases, having a density ratio of approximately seven, provide an effective means of simulating compressible shear layers. Statistical autocorrelation functions and structure functions are computed on the reconstructed phase maps. The autocorrelation function results indicate that the turbulence-induced phase fluctuations are not wide-sense stationary. The structure functions exhibit statistical homogeneity, indicating the phase fluctuation are stationary in first increments. However, the turbulence-corrupted phase is not isotropic. A five-thirds power law is shown to fit one-dimensional, orthogonal slices of the structure function, with scaling coefficients related to the location in the flow.

Parametrizing growth in dark energy and modified gravity models

NASA Astrophysics Data System (ADS)

Resco, Miguel Aparicio; Maroto, Antonio L.

2018-02-01

It is well known that an extremely accurate parametrization of the growth function of matter density perturbations in Λ CDM cosmology, with errors below 0.25%, is given by f (a )=Ωmγ(a ) with γ ≃0.55 . In this work, we show that a simple modification of this expression also provides a good description of growth in modified gravity theories. We consider the model-independent approach to modified gravity in terms of an effective Newton constant written as μ (a ,k )=Geff/G and show that f (a )=β (a )Ωmγ(a ) provides fits to the numerical solutions with similar accuracy to that of Λ CDM . In the time-independent case with μ =μ (k ), simple analytic expressions for β (μ ) and γ (μ ) are presented. In the time-dependent (but scale-independent) case μ =μ (a ), we show that β (a ) has the same time dependence as μ (a ). As an example, explicit formulas are provided in the Dvali-Gabadadze-Porrati (DGP) model. In the general case, for theories with μ (a ,k ), we obtain a perturbative expansion for β (μ ) around the general relativity case μ =1 which, for f (R ) theories, reaches an accuracy below 1%. Finally, as an example we apply the obtained fitting functions in order to forecast the precision with which future galaxy surveys will be able to measure the μ parameter.

A Physical Activity Program Improves Behavior and Cognitive Functions in Children with ADHD: An Exploratory Study

ERIC Educational Resources Information Center

Verret, Claudia; Guay, Marie-Claude; Berthiaume, Claude; Gardiner, Phillip; Beliveau, Louise

2012-01-01

Objective: The objective of this study is to explore the effects of a moderate- to high-intensity physical activity program on fitness, cognitive functions, and ADHD-related behavior in children with ADHD. Method: Fitness level, motor skills, behaviors, and cognitive functions are assessed by standardized tests before and after a 10-week training…

Tight-binding calculation of single-band and generalized Wannier functions of graphene

NASA Astrophysics Data System (ADS)

Ribeiro, Allan Victor; Bruno-Alfonso, Alexys

Recent work has shown that a tight-binding approach associated with Wannier functions (WFs) provides an intuitive physical image of the electronic structure of graphene. Regarding the case of graphene, Marzari et al. displayed the calculated WFs and presented a comparison between the Wannier-interpolated bands and the bands generated by using the density-functional code. Jung and MacDonald provided a tight-binding model for the π-bands of graphene that involves maximally localized Wannier functions (MLWFs). The mixing of the bands yields better localized WFs. In the present work, the MLWFs of graphene are calculated by combining the Quantum-ESPRESSO code and tight-binding approach. The MLWFs of graphene are calculated from the Bloch functions obtained through a tight binding approach that includes interactions and overlapping obtained by partially fitting the DFT bands. The phase of the Bloch functions of each band is appropriately chosen to produce MLWFs. The same thing applies to the coefficients of their linear combination in the generalized case. The method allows for an intuitive understanding of the maximally localized WFs of graphene and shows excellent agreement with the literature. Moreover, it provides accurate results at reduced computational cost.

Three-dimensional whole-brain perfusion quantification using pseudo-continuous arterial spin labeling MRI at multiple post-labeling delays: accounting for both arterial transit time and impulse response function.

PubMed

Qin, Qin; Huang, Alan J; Hua, Jun; Desmond, John E; Stevens, Robert D; van Zijl, Peter C M

2014-02-01

Measurement of the cerebral blood flow (CBF) with whole-brain coverage is challenging in terms of both acquisition and quantitative analysis. In order to fit arterial spin labeling-based perfusion kinetic curves, an empirical three-parameter model which characterizes the effective impulse response function (IRF) is introduced, which allows the determination of CBF, the arterial transit time (ATT) and T(1,eff). The accuracy and precision of the proposed model were compared with those of more complicated models with four or five parameters through Monte Carlo simulations. Pseudo-continuous arterial spin labeling images were acquired on a clinical 3-T scanner in 10 normal volunteers using a three-dimensional multi-shot gradient and spin echo scheme at multiple post-labeling delays to sample the kinetic curves. Voxel-wise fitting was performed using the three-parameter model and other models that contain two, four or five unknown parameters. For the two-parameter model, T(1,eff) values close to tissue and blood were assumed separately. Standard statistical analysis was conducted to compare these fitting models in various brain regions. The fitted results indicated that: (i) the estimated CBF values using the two-parameter model show appreciable dependence on the assumed T(1,eff) values; (ii) the proposed three-parameter model achieves the optimal balance between the goodness of fit and model complexity when compared among the models with explicit IRF fitting; (iii) both the two-parameter model using fixed blood T1 values for T(1,eff) and the three-parameter model provide reasonable fitting results. Using the proposed three-parameter model, the estimated CBF (46 ± 14 mL/100 g/min) and ATT (1.4 ± 0.3 s) values averaged from different brain regions are close to the literature reports; the estimated T(1,eff) values (1.9 ± 0.4 s) are higher than the tissue T1 values, possibly reflecting a contribution from the microvascular arterial blood compartment. Copyright © 2013 John Wiley & Sons, Ltd.

Improvement to microphysical schemes in WRF Model based on observed data, part I: size distribution function

NASA Astrophysics Data System (ADS)

Shan, Y.; Eric, W.; Gao, L.; Zhao, T.; Yin, Y.

2015-12-01

In this study, we have evaluated the performance of size distribution functions (SDF) with 2- and 3-moments in fitting the observed size distribution of rain droplets at three different heights. The goal is to improve the microphysics schemes in meso-scale models, such as Weather Research and Forecast (WRF). Rain droplets were observed during eight periods of different rain types at three stations on the Yellow Mountain in East China. The SDF in this study were M-P distribution with a fixed shape parameter in Gamma SDF(FSP). Where the Gamma SDFs were obtained with three diagnosis methods with the shape parameters based on Milbrandt (2010; denoted DSPM10), Milbrandt (2005; denoted DSPM05) and Seifert (2008; denoted DSPS08) for solving the shape parameter(SSP) and Lognormal SDF. Based on the preliminary experiments, three ensemble methods deciding Gamma SDF was also developed and assessed. The magnitude of average relative error caused by applying a FSP was 10-2 for fitting 0-order moment of the observed rain droplet distribution, and the magnitude of average relative error changed to 10-1 and 100 respectively for 1-4 order moments and 5-6 order moments. To different extent, DSPM10, DSPM05, DSPS08, SSP and ensemble methods could improve fitting accuracies for 0-6 order moments, especially the one coupling SSP and DSPS08 methods, which provided a average relative error 6.46% for 1-4 order moments and 11.90% for 5-6 order moments, respectively. The relative error of fitting three moments using the Lognormal SDF was much larger than that of Gamma SDF. The threshold value of shape parameter ranged from 0 to 8, because values beyond this range could cause overflow in the calculation. When average diameter of rain droplets was less than 2mm, the possibility of unavailable shape parameter value(USPV) increased with a decreasing droplet size. There was strong sensitivity of moment group in fitting accuracy. When ensemble method coupling SSP and DSPS08 was used, a better fit to 1-3-5 moments of the SDF was possible compared to fitting the 0-3-6 moment group.

Enabling Computational Nanotechnology through JavaGenes in a Cycle Scavenging Environment

NASA Technical Reports Server (NTRS)

Globus, Al; Menon, Madhu; Srivastava, Deepak; Biegel, Bryan A. (Technical Monitor)

2002-01-01

A genetic algorithm procedure is developed and implemented for fitting parameters for many-body inter-atomic force field functions for simulating nanotechnology atomistic applications using portable Java on cycle-scavenged heterogeneous workstations. Given a physics based analytic functional form for the force field, correlated parameters in a multi-dimensional environment are typically chosen to fit properties given either by experiments and/or by higher accuracy quantum mechanical simulations. The implementation automates this tedious procedure using an evolutionary computing algorithm operating on hundreds of cycle-scavenged computers. As a proof of concept, we demonstrate the procedure for evaluating the Stillinger-Weber (S-W) potential by (a) reproducing the published parameters for Si using S-W energies in the fitness function, and (b) evolving a "new" set of parameters using semi-empirical tightbinding energies in the fitness function. The "new" parameters are significantly better suited for Si cluster energies and forces as compared to even the published S-W potential.

Brain MRI Tumor Detection using Active Contour Model and Local Image Fitting Energy

NASA Astrophysics Data System (ADS)

Nabizadeh, Nooshin; John, Nigel

2014-03-01

Automatic abnormality detection in Magnetic Resonance Imaging (MRI) is an important issue in many diagnostic and therapeutic applications. Here an automatic brain tumor detection method is introduced that uses T1-weighted images and K. Zhang et. al.'s active contour model driven by local image fitting (LIF) energy. Local image fitting energy obtains the local image information, which enables the algorithm to segment images with intensity inhomogeneities. Advantage of this method is that the LIF energy functional has less computational complexity than the local binary fitting (LBF) energy functional; moreover, it maintains the sub-pixel accuracy and boundary regularization properties. In Zhang's algorithm, a new level set method based on Gaussian filtering is used to implement the variational formulation, which is not only vigorous to prevent the energy functional from being trapped into local minimum, but also effective in keeping the level set function regular. Experiments show that the proposed method achieves high accuracy brain tumor segmentation results.

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.

29 CFR 825.312 - Fitness-for-duty certification.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 3 2014-07-01 2014-07-01 false Fitness-for-duty certification. 825.312 Section 825.312... § 825.312 Fitness-for-duty certification. (a) As a condition of restoring an employee whose FMLA leave... provider to provide the information directly to the employer) in the fitness-for-duty certification process...

29 CFR 825.312 - Fitness-for-duty certification.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 3 2012-07-01 2012-07-01 false Fitness-for-duty certification. 825.312 Section 825.312... § 825.312 Fitness-for-duty certification. (a) As a condition of restoring an employee whose FMLA leave... provider to provide the information directly to the employer) in the fitness-for-duty certification process...

29 CFR 825.312 - Fitness-for-duty certification.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 3 2013-07-01 2013-07-01 false Fitness-for-duty certification. 825.312 Section 825.312... § 825.312 Fitness-for-duty certification. (a) As a condition of restoring an employee whose FMLA leave... provider to provide the information directly to the employer) in the fitness-for-duty certification process...

29 CFR 825.312 - Fitness-for-duty certification.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false Fitness-for-duty certification. 825.312 Section 825.312... § 825.312 Fitness-for-duty certification. (a) As a condition of restoring an employee whose FMLA leave... provider to provide the information directly to the employer) in the fitness-for-duty certification process...

29 CFR 825.312 - Fitness-for-duty certification.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 3 2011-07-01 2011-07-01 false Fitness-for-duty certification. 825.312 Section 825.312... § 825.312 Fitness-for-duty certification. (a) As a condition of restoring an employee whose FMLA leave... provider to provide the information directly to the employer) in the fitness-for-duty certification process...

On the dielectric conductivity of molecular ionic liquids.

PubMed

Schröder, Christian; Steinhauser, Othmar

2009-09-21

The contribution of the conductivity to the spectrum of the generalized dielectric constant or susceptibility of molecular ionic liquids is analyzed, both in theoretical terms and computationally by means of molecular dynamics simulation of the concrete system 1-ethyl-3-methyl-imidazolium dicyanoamide at 300 K. As a central quantity the simulated current autocorrelation function is modeled by a carefully designed fit function. This not only gives a satisfactory numerical representation but yields the correct conductivity upon integration. In addition the fit function can be Fourier-Laplace transformed analytically. Both, the real and imaginary parts of the transform show expected behavior, in particular, the right limits for zero frequency. This altogether demonstrates that the components of the fit function are of physical relevance.

Functional Imagery Training to reduce snacking: Testing a novel motivational intervention based on Elaborated Intrusion theory.

PubMed

Andrade, Jackie; Khalil, Marina; Dickson, Jennifer; May, Jon; Kavanagh, David J

2016-05-01

Functional Imagery Training (FIT) is a new theory-based, manualized intervention that trains positive goal imagery. Multisensory episodic imagery of proximal personal goals is elicited and practised, to sustain motivation and compete with less functional cravings. This study tested the impact of a single session of FIT plus a booster phone call on snacking. In a stepped-wedge design, 45 participants who wanted to lose weight or reduce snacking were randomly assigned to receive a session of FIT immediately or after a 2-week delay. High-sugar and high-fat snacks were recorded using timeline follow back for the previous 3 days, at baseline, 2 and 4 weeks. At 2 weeks, snacking was lower in the immediate group than in the delayed group, and the reduction after FIT was replicated in the delayed group between 2 and 4 weeks. Frequencies of motivational thoughts about snack reduction rose following FIT for both groups, and this change correlated with reductions in snacking and weight loss. By showing that FIT can support change in eating behaviours, these findings show its potential as a motivational intervention for weight management. Copyright © 2016 Elsevier Ltd. All rights reserved.

Combined Iron Deficiency and Low Aerobic Fitness Doubly Burden Academic Performance among Women Attending University.

PubMed

Scott, Samuel P; De Souza, Mary Jane; Koehler, Karsten; Murray-Kolb, Laura E

2017-01-01

Academic success is a key determinant of future prospects for students. Cognitive functioning has been related to nutritional and physical factors. Here, we focus on iron status and aerobic fitness in young-adult female students given the high rate of iron deficiency and declines in fitness reported in this population. We sought to explore the combined effects of iron status and fitness on academic success and to determine whether these associations are mediated by cognitive performance. Women (n = 105) aged 18-35 y were recruited for this cross-sectional study. Data were obtained for iron biomarkers, peak oxygen uptake (VO 2peak ), grade point average (GPA), performance on computerized attention and memory tasks, and motivation and parental occupation. We compared the GPA of groups 1) with low compared with normal iron status, 2) among different fitness levels, and 3) by using a combined iron status and fitness designation. Mediation analysis was applied to determine whether iron status and VO 2peak influence GPA through attentional and mnemonic function. After controlling for age, parental occupation, and motivation, GPA was higher in women with normal compared with low ferritin (3.66 ± 0.06 compared with 3.39 ± 0.06; P = 0.01). In analyses of combined effects of iron status and fitness, GPA was higher in women with normal ferritin and higher fitness (3.70 ± 0.08) than in those with 1) low ferritin and lower fitness (3.36 ± 0.08; P = 0.02) and 2) low ferritin and higher fitness (3.44 ± 0.09; P = 0.04). Path analysis revealed that working memory mediated the association between VO 2peak and GPA. Low iron stores and low aerobic fitness may prevent female college students from achieving their full academic potential. Investigators should explore whether integrated lifestyle interventions targeting nutritional status and fitness can benefit cognitive function, academic success, and postgraduate prospects. © 2017 American Society for Nutrition.

A space-based climatology of diurnal MLT tidal winds, temperatures and densities from UARS wind measurements

NASA Astrophysics Data System (ADS)

Svoboda, Aaron A.; Forbes, Jeffrey M.; Miyahara, Saburo

2005-11-01

A self-consistent global tidal climatology, useful for comparing and interpreting radar observations from different locations around the globe, is created from space-based Upper Atmosphere Research Satellite (UARS) horizontal wind measurements. The climatology created includes tidal structures for horizontal winds, temperature and relative density, and is constructed by fitting local (in latitude and height) UARS wind data at 95 km to a set of basis functions called Hough mode extensions (HMEs). These basis functions are numerically computed modifications to Hough modes and are globally self-consistent in wind, temperature, and density. We first demonstrate this self-consistency with a proxy data set from the Kyushu University General Circulation Model, and then use a linear weighted superposition of the HMEs obtained from monthly fits to the UARS data to extrapolate the global, multi-variable tidal structure. A brief explanation of the HMEs’ origin is provided as well as information about a public website that has been set up to make the full extrapolated data sets available.

A bottom-up characterization of transfer functions for synthetic biology designs: lessons from enzymology

PubMed Central

Carbonell-Ballestero, Max; Duran-Nebreda, Salva; Montañez, Raúl; Solé, Ricard; Macía, Javier; Rodríguez-Caso, Carlos

2014-01-01

Within the field of synthetic biology, a rational design of genetic parts should include a causal understanding of their input-output responses—the so-called transfer function—and how to tune them. However, a commonly adopted strategy is to fit data to Hill-shaped curves without considering the underlying molecular mechanisms. Here we provide a novel mathematical formalization that allows prediction of the global behavior of a synthetic device by considering the actual information from the involved biological parts. This is achieved by adopting an enzymology-like framework, where transfer functions are described in terms of their input affinity constant and maximal response. As a proof of concept, we characterize a set of Lux homoserine-lactone-inducible genetic devices with different levels of Lux receptor and signal molecule. Our model fits the experimental results and predicts the impact of the receptor's ribosome-binding site strength, as a tunable parameter that affects gene expression. The evolutionary implications are outlined. PMID:25404136

ISAP: ISO Spectral Analysis Package

NASA Astrophysics Data System (ADS)

Ali, Babar; Bauer, Otto; Brauher, Jim; Buckley, Mark; Harwood, Andrew; Hur, Min; Khan, Iffat; Li, Jing; Lord, Steve; Lutz, Dieter; Mazzarella, Joe; Molinari, Sergio; Morris, Pat; Narron, Bob; Seidenschwang, Karla; Sidher, Sunil; Sturm, Eckhard; Swinyard, Bruce; Unger, Sarah; Verstraete, Laurent; Vivares, Florence; Wieprecht, Ecki

2014-03-01

ISAP, written in IDL, simplifies the process of visualizing, subsetting, shifting, rebinning, masking, combining scans with weighted means or medians, filtering, and smoothing Auto Analysis Results (AARs) from post-pipeline processing of the Infrared Space Observatory's (ISO) Short Wavelength Spectrometer (SWS) and Long Wavelength Spectrometer (LWS) data. It can also be applied to PHOT-S and CAM-CVF data, and data from practically any spectrometer. The result of a typical ISAP session is expected to be a "simple spectrum" (single-valued spectrum which may be resampled to a uniform wavelength separation if desired) that can be further analyzed and measured either with other ISAP functions, native IDL functions, or exported to other analysis package (e.g., IRAF, MIDAS) if desired. ISAP provides many tools for further analysis, line-fitting, and continuum measurements, such as routines for unit conversions, conversions from wavelength space to frequency space, line and continuum fitting, flux measurement, synthetic photometry and models such as a zodiacal light model to predict and subtract the dominant foreground at some wavelengths.

Estimation of Psychophysical Thresholds Based on Neural Network Analysis of DPOAE Input/Output Functions

NASA Astrophysics Data System (ADS)

Naghibolhosseini, Maryam; Long, Glenis

2011-11-01

The distortion product otoacoustic emission (DPOAE) input/output (I/O) function may provide a potential tool for evaluating cochlear compression. Hearing loss causes an increase in the level of the sound that is just audible for the person, which affects the cochlea compression and thus the dynamic range of hearing. Although the slope of the I/O function is highly variable when the total DPOAE is used, separating the nonlinear-generator component from the reflection component reduces this variability. We separated the two components using least squares fit (LSF) analysis of logarithmic sweeping tones, and confirmed that the separated generator component provides more consistent I/O functions than the total DPOAE. In this paper we estimated the slope of the I/O functions of the generator components at different sound levels using LSF analysis. An artificial neural network (ANN) was used to estimate psychophysical thresholds using the estimated slopes of the I/O functions. DPOAE I/O functions determined in this way may help to estimate hearing thresholds and cochlear health.

Occupational medical prophylaxis for the musculoskeletal system: A function-oriented system for physical examination of the locomotor system in occupational medicine (fokus(C)).

PubMed

Spallek, Michael; Kuhn, Walter; Schwarze, Sieglinde; Hartmann, Bernd

2007-10-29

Occupational physicians are very often confronted with questions as to the fitness of the postural and locomotor systems, especially the spinal column. Occupational medical assessment and advice can be required by patients with acute symptoms, at routine check-ups, by persons who have problems doing certain jobs, and for expert medical reports as to the fitness of persons with chronic disorders or after operations. Therefore, for occupational medical purposes a physical examination must aim primarily to investigate functions and not structures or radiologic evidence. The physical examination should be structured systematically and according to regions of the body and, together with a specific (pain) anamnesis should provide a basis for the medical assessment.This paper presents a function-oriented system for physical examination of the locomotor system, named fokus(C) (Funktionsorientierte Koerperliche Untersuchungssystematik, also available on DVD). fokus(C) has been developed with a view to its relevance for occupational medical practice and does not aim primarily to provide a precise diagnosis. Decisive for an occupational medical assessment of disorders of the musculoskeletal system is rather information about functional disorders and any impairment of performance or mobility which they can cause. The division of the physical examination into a rapid screening phase and a subsequent more intensive functional diagnostic phase has proved its practicability in many years of day-to-day use. Here, in contrast to the very extensive measures recommended for orthopaedic and manual diagnosis, for reasons of efficiency and usability of the system in routine occupational medical examinations the examination is structured according to the findings. So it is reduced to that which is most necessary and feasible.

Evolving Multi Rover Systems in Dynamic and Noisy Environments

NASA Technical Reports Server (NTRS)

Tumer, Kagan; Agogino, Adrian

2005-01-01

In this chapter, we address how to evolve control strategies for a collective: a set of entities that collectively strives to maximize a global evaluation function that rates the performance of the full system. Addressing such problems by directly applying a global evolutionary algorithm to a population of collectives is unworkable because the search space is prohibitively large. Instead, we focus on evolving control policies for each member of the collective, where each member is trying to maximize the fitness of its own population. The main difficulty with this approach is creating fitness evaluation functions for the members of the collective that induce the collective to achieve high performance with respect to the system level goal. To overcome this difficulty, we derive member evaluation functions that are both aligned with the global evaluation function (ensuring that members trying to achieve high fitness results in a collective with high fitness) and sensitive to the fitness of each member (a member's fitness depends more on its own actions than on actions of other members). In a difficult rover coordination problem in dynamic and noisy environments, we show how to construct evaluation functions that lead to good collective behavior. The control policy evolved using aligned and member-sensitive evaluations outperforms global evaluation methods by up to a factor of four. in addition we show that the collective continues to perform well in the presence of high noise levels and when the environment is highly dynamic. More notably, in the presence of a larger number of rovers or rovers with noisy sensors, the improvements due to the proposed method become significantly more pronounced.

Surface complexation modeling of zinc sorption onto ferrihydrite.

PubMed

Dyer, James A; Trivedi, Paras; Scrivner, Noel C; Sparks, Donald L

2004-02-01

A previous study involving lead(II) [Pb(II)] sorption onto ferrihydrite over a wide range of conditions highlighted the advantages of combining molecular- and macroscopic-scale investigations with surface complexation modeling to predict Pb(II) speciation and partitioning in aqueous systems. In this work, an extensive collection of new macroscopic and spectroscopic data was used to assess the ability of the modified triple-layer model (TLM) to predict single-solute zinc(II) [Zn(II)] sorption onto 2-line ferrihydrite in NaNO(3) solutions as a function of pH, ionic strength, and concentration. Regression of constant-pH isotherm data, together with potentiometric titration and pH edge data, was a much more rigorous test of the modified TLM than fitting pH edge data alone. When coupled with valuable input from spectroscopic analyses, good fits of the isotherm data were obtained with a one-species, one-Zn-sorption-site model using the bidentate-mononuclear surface complex, (triple bond FeO)(2)Zn; however, surprisingly, both the density of Zn(II) sorption sites and the value of the best-fit equilibrium "constant" for the bidentate-mononuclear complex had to be adjusted with pH to adequately fit the isotherm data. Although spectroscopy provided some evidence for multinuclear surface complex formation at surface loadings approaching site saturation at pH >/=6.5, the assumption of a bidentate-mononuclear surface complex provided acceptable fits of the sorption data over the entire range of conditions studied. Regressing edge data in the absence of isotherm and spectroscopic data resulted in a fair number of surface-species/site-type combinations that provided acceptable fits of the edge data, but unacceptable fits of the isotherm data. A linear relationship between logK((triple bond FeO)2Zn) and pH was found, given by logK((triple bond FeO)2Znat1g/l)=2.058 (pH)-6.131. In addition, a surface activity coefficient term was introduced to the model to reduce the ionic strength dependence of sorption. The results of this research and previous work with Pb(II) indicate that the existing thermodynamic framework for the modified TLM is able to reproduce the metal sorption data only over a limited range of conditions. For this reason, much work still needs to be done in fine-tuning the thermodynamic framework and databases for the TLM.

Methods for fitting a parametric probability distribution to most probable number data.

PubMed

Williams, Michael S; Ebel, Eric D

2012-07-02

Every year hundreds of thousands, if not millions, of samples are collected and analyzed to assess microbial contamination in food and water. The concentration of pathogenic organisms at the end of the production process is low for most commodities, so a highly sensitive screening test is used to determine whether the organism of interest is present in a sample. In some applications, samples that test positive are subjected to quantitation. The most probable number (MPN) technique is a common method to quantify the level of contamination in a sample because it is able to provide estimates at low concentrations. This technique uses a series of dilution count experiments to derive estimates of the concentration of the microorganism of interest. An application for these data is food-safety risk assessment, where the MPN concentration estimates can be fitted to a parametric distribution to summarize the range of potential exposures to the contaminant. Many different methods (e.g., substitution methods, maximum likelihood and regression on order statistics) have been proposed to fit microbial contamination data to a distribution, but the development of these methods rarely considers how the MPN technique influences the choice of distribution function and fitting method. An often overlooked aspect when applying these methods is whether the data represent actual measurements of the average concentration of microorganism per milliliter or the data are real-valued estimates of the average concentration, as is the case with MPN data. In this study, we propose two methods for fitting MPN data to a probability distribution. The first method uses a maximum likelihood estimator that takes average concentration values as the data inputs. The second is a Bayesian latent variable method that uses the counts of the number of positive tubes at each dilution to estimate the parameters of the contamination distribution. The performance of the two fitting methods is compared for two data sets that represent Salmonella and Campylobacter concentrations on chicken carcasses. The results demonstrate a bias in the maximum likelihood estimator that increases with reductions in average concentration. The Bayesian method provided unbiased estimates of the concentration distribution parameters for all data sets. We provide computer code for the Bayesian fitting method. Published by Elsevier B.V.

The predictive power of physical function assessed by questionnaire and physical performance measures for subsequent disability.

PubMed

Hoshi, Masayuki; Hozawa, Atsushi; Kuriyama, Shinichi; Nakaya, Naoki; Ohmori-Matsuda, Kaori; Sone, Toshimasa; Kakizaki, Masako; Niu, Kaijun; Fujita, Kazuki; Ueki, Shouzoh; Haga, Hiroshi; Nagatomi, Ryoichi; Tsuji, Ichiro

2012-08-01

To compare the predictive power of physical function assessed by questionnaire and physical performance measures for subsequent disability in community-dwelling elderly persons. Prospective cohort study. Participants were 813 aged 70 years and older, elderly Japanese residing in the community, included in the Tsurugaya Project, who were not disabled at the baseline in 2003. Physical function was assessed by the questionnaire of "Motor Fitness Scale". Physical performance measures consisted of maximum walking velocity, timed up and go test (TUG), leg extension power, and functional reach test. The area under the curve (AUC) of the receiver operating characteristic curve for disability was used to compare screening accuracy between Motor Fitness Scale and physical performance measures. Incident disability, defined as certification for long-term care insurance, was used as the endpoint. We observed 135 cases of incident disability during follow-up. The third or fourth quartile for each measure was associated with a significantly increased risk of disability in comparison with the highest quartile. The AUC was 0.70, 0.72, 0.70, 0.68, 0.69 and 0.74, for Motor Fitness Scale, maxi- mum walking velocity, TUG, leg extension power, functional reach test, and total performance score, respectively. The predictive power of physical function assessed by the Motor Fitness Scale was equivalent to that assessed by physical performance measures. Since Motor Fitness Scale can evaluate physical function safely and simply in comparison with physical performance tests, it would be a practical tool for screening persons at high risk of disability.

Automated generation of influence functions for planar crack problems

NASA Technical Reports Server (NTRS)

Sire, Robert A.; Harris, David O.; Eason, Ernest D.

1989-01-01

A numerical procedure for the generation of influence functions for Mode I planar problems is described. The resulting influence functions are in a form for convenient evaluation of stress-intensity factors for complex stress distributions. Crack surface displacements are obtained by a least-squares solution of the Williams eigenfunction expansion for displacements in a cracked body. Discrete values of the influence function, evaluated using the crack surface displacements, are curve fit using an assumed functional form. The assumed functional form includes appropriate limit-behavior terms for very deep and very shallow cracks. Continuous representation of the influence function provides a convenient means for evaluating stress-intensity factors for arbitrary stress distributions by numerical integration. The procedure is demonstrated for an edge-cracked strip and a radially cracked disk. Comparisons with available published results demonstrate the accuracy of the procedure.

Incipient Balancing Selection through Adaptive Loss of Aquaporins in Natural Saccharomyces cerevisiae Populations

PubMed Central

Will, Jessica L.; Kim, Hyun Seok; Clarke, Jessica; Painter, John C.; Fay, Justin C.; Gasch, Audrey P.

2010-01-01

A major goal in evolutionary biology is to understand how adaptive evolution has influenced natural variation, but identifying loci subject to positive selection has been a challenge. Here we present the adaptive loss of a pair of paralogous genes in specific Saccharomyces cerevisiae subpopulations. We mapped natural variation in freeze-thaw tolerance to two water transporters, AQY1 and AQY2, previously implicated in freeze-thaw survival. However, whereas freeze-thaw–tolerant strains harbor functional aquaporin genes, the set of sensitive strains lost aquaporin function at least 6 independent times. Several genomic signatures at AQY1 and/or AQY2 reveal low variation surrounding these loci within strains of the same haplotype, but high variation between strain groups. This is consistent with recent adaptive loss of aquaporins in subgroups of strains, leading to incipient balancing selection. We show that, although aquaporins are critical for surviving freeze-thaw stress, loss of both genes provides a major fitness advantage on high-sugar substrates common to many strains' natural niche. Strikingly, strains with non-functional alleles have also lost the ancestral requirement for aquaporins during spore formation. Thus, the antagonistic effect of aquaporin function—providing an advantage in freeze-thaw tolerance but a fitness defect for growth in high-sugar environments—contributes to the maintenance of both functional and nonfunctional alleles in S. cerevisiae. This work also shows that gene loss through multiple missense and nonsense mutations, hallmarks of pseudogenization presumed to emerge after loss of constraint, can arise through positive selection. PMID:20369021