Comparing the rankings obtained from two biodiversity indices: the Fair Proportion Index and the Shapley Value.

PubMed

Wicke, Kristina; Fischer, Mareike

2017-10-07

The Shapley Value and the Fair Proportion Index of phylogenetic trees have been frequently discussed as prioritization tools in conservation biology. Both indices rank species according to their contribution to total phylogenetic diversity, allowing for a simple conservation criterion. While both indices have their specific advantages and drawbacks, it has recently been shown that both values are closely related. However, as different authors use different definitions of the Shapley Value, the specific degree of relatedness depends on the specific version of the Shapley Value - it ranges from a high correlation index to equality of the indices. In this note, we first give an overview of the different indices. Then we turn our attention to the mere ranking order provided by either of the indices. We compare the rankings obtained from different versions of the Shapley Value for a phylogenetic tree of European amphibians and illustrate their differences. We then undertake further analyses on simulated data and show that even though the chance of two rankings being exactly identical (when obtained from different versions of the Shapley Value) decreases with an increasing number of taxa, the distance between the two rankings converges to zero, i.e., the rankings are becoming more and more alike. Moreover, we introduce our freely available software package FairShapley, which was implemented in Perl and with which all calculations have been performed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Adjusting Permittivity by Blending Varying Ratios of SWNTs

NASA Technical Reports Server (NTRS)

Tour, James M.; Stephenson, Jason J.; Higginbotham, Amanda

2012-01-01

A new composite material of singlewalled carbon nanotubes (SWNTs) displays radio frequency (0 to 1 GHz) permittivity properties that can be adjusted based upon the nanotube composition. When varying ratios of raw to functionalized SWNTs are blended into the silicone elastomer matrix at a total loading of 0.5 percent by weight, a target real permittivity value can be obtained between 70 and 3. This has particular use for designing materials for microwave lenses, microstrips, filters, resonators, high-strength/low-weight electromagnetic interference (EMI) shielding, antennas, waveguides, and low-loss magneto-dielectric products for applications like radome construction.

Obtaining Parts

Science.gov Websites

The Cosmic Connection Parts for the Berkeley Detector Suppliers: Scintillator Eljen Technology 1 obtain the components needed to build the Berkeley Detector. These companies have helped previous the last update. He estimates that the cost to build a detector varies from $1500 to $2700 depending

Application of Hamilton's law of varying action

NASA Technical Reports Server (NTRS)

Bailey, C. D.

1975-01-01

The law of varying action enunciated by Hamilton in 1834-1835 permits the direct analytical solution of the problems of mechanics, both stationary and nonstationary, without consideration of force equilibrium and the theory of differential equations associated therewith. It has not been possible to obtain direct analytical solutions to nonstationary systems through the use of energy theory, which has been limited for 140 years to the principle of least action and to Hamilton's principle. It is shown here that Hamilton's law permits the direct analytical solution to nonstationary, initial value systems in the mechanics of solids without any knowledge or use of the theory of differential equations. Solutions are demonstrated for nonconservative, nonstationary particle motion, both linear and nonlinear.

Relationship between sweat chloride, sodium, and age in clinically obtained samples.

PubMed

Traeger, Nadav; Shi, Qiuhu; Dozor, Allen J

2014-01-01

The relationship between sweat electrolytes and age is uncertain, as is the value of measuring sodium or the chloride:sodium ratio. 13,785 sweat tests performed over 23 years at one center through the Macroduct collection in clinically obtained samples were analyzed. Sweat chloride tended to decrease over the first year of life, slowly increase until the fourth decade, then either level off or slightly decrease. In children, sweat sodium overlapped between those with positive and negative sweat tests, but not in adults. If the sweat test was positive, there was a higher likelihood of having a chloride:sodium ratio >1, but most subjects with a ratio >1 did not have CF. Sweat chloride and sodium vary with age. Measurement of sweat sodium did not add discriminatory value. The proportion of subjects with a chloride:sodium ratio >1, with or without CF, varied greatly between age ranges. © 2013. Published by Elsevier B.V. on behalf of European Cystic Fibrosis Society. All rights reserved.

Time varying default barrier as an agreement rules on bond contract

NASA Astrophysics Data System (ADS)

Maruddani, Di Asih I.; Safitri, Diah; Hoyyi, Abdul

2018-05-01

There are some default time rules on contract agreement of a bond. The classical default time is known as Merton Model. The most important characteristic of Merton’s model is the restriction of default time to the maturity of the debt, not taking into consideration the possibility of an early default. If the firm’s value falls down to minimal level before the maturity of the debt, but it is able to recover and meet the debt’s payment at maturity, the default would be avoided in Merton’ s approach. Merton model has been expanded by Hull & White [6] and Avellaneda & Zhu [1]. They introduced time-varying default barrier for modelling distance to default process. This model use time-varying variable as a barrier. In this paper, we give a valuation of a bond with time-varying default barrier agreement. We use straight forward integration for obtaining equity and liability equation. This theory is applied in Indonesian corporate bond.

Comparison of oxygen saturation values obtained from fingers on physically restrained or unrestrained sides of the body.

PubMed

Korhan, Esra Akin; Yönt, Gülendam Hakverdioğlu; Khorshid, Leyla

2011-01-01

The aim of this study was to compare semiexperimentally the pulse oximetry values obtained from a finger on restrained or unrestrained sides of the body. The pulse oximeter provides a noninvasive measurement of the oxygen saturation of hemoglobin in arterial blood. One of the procedures most frequently applied to patients in intensive care units is the application of physical restraint. Circulation problems are the most important complication in patients who are physically restrained. Evaluation of oxygen saturation from body parts in which circulation is impeded or has deteriorated can cause false results. The research sample consisted of 30 hospitalized patients who participated in the study voluntarily and who were concordant with the inclusion criteria of the study. Patient information and patient follow-up forms were used for data collection. Pulse oximetry values were measured simultaneously using OxiMax Nellcor finger sensors from fingers on the restrained and unrestrained sides of the body. Numeric and percentile distributions were used in evaluating the sociodemographic properties of patients. A significant difference was found between the oxygen saturation values obtained from a finger of an arm that had been physically restrained and a finger of an arm that had not been physically restrained. The mean oxygen saturation value measured from a finger of an arm that had been physically restrained was found to be 93.40 (SD, 2.97), and the mean oxygen saturation value measured from a finger of an arm that had not been physically restrained was found to be 95.53 (SD, 2.38). The results of this study indicate that nurses should use a finger of an arm that is not physically restrained when evaluating oxygen saturation values to evaluate them correctly.

Comparison of internal dose estimates obtained using organ-level, voxel S value, and Monte Carlo techniques

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

Grimes, Joshua, E-mail: grimes.joshua@mayo.edu; Celler, Anna

2014-09-15

Purpose: The authors’ objective was to compare internal dose estimates obtained using the Organ Level Dose Assessment with Exponential Modeling (OLINDA/EXM) software, the voxel S value technique, and Monte Carlo simulation. Monte Carlo dose estimates were used as the reference standard to assess the impact of patient-specific anatomy on the final dose estimate. Methods: Six patients injected with{sup 99m}Tc-hydrazinonicotinamide-Tyr{sup 3}-octreotide were included in this study. A hybrid planar/SPECT imaging protocol was used to estimate {sup 99m}Tc time-integrated activity coefficients (TIACs) for kidneys, liver, spleen, and tumors. Additionally, TIACs were predicted for {sup 131}I, {sup 177}Lu, and {sup 90}Y assuming themore » same biological half-lives as the {sup 99m}Tc labeled tracer. The TIACs were used as input for OLINDA/EXM for organ-level dose calculation and voxel level dosimetry was performed using the voxel S value method and Monte Carlo simulation. Dose estimates for {sup 99m}Tc, {sup 131}I, {sup 177}Lu, and {sup 90}Y distributions were evaluated by comparing (i) organ-level S values corresponding to each method, (ii) total tumor and organ doses, (iii) differences in right and left kidney doses, and (iv) voxelized dose distributions calculated by Monte Carlo and the voxel S value technique. Results: The S values for all investigated radionuclides used by OLINDA/EXM and the corresponding patient-specific S values calculated by Monte Carlo agreed within 2.3% on average for self-irradiation, and differed by as much as 105% for cross-organ irradiation. Total organ doses calculated by OLINDA/EXM and the voxel S value technique agreed with Monte Carlo results within approximately ±7%. Differences between right and left kidney doses determined by Monte Carlo were as high as 73%. Comparison of the Monte Carlo and voxel S value dose distributions showed that each method produced similar dose volume histograms with a minimum dose covering 90% of the volume

7 CFR 356.4 - Property valued at $10,000 or less; notice of seizure administrative action to obtain forfeiture.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Property valued at $10,000 or less; notice of seizure... PROCEDURES § 356.4 Property valued at $10,000 or less; notice of seizure administrative action to obtain... notice of seizure and proposed forfeiture as provided in paragraph (c)(1) of this section, by posting for...

Perturbation analysis of queueing systems with a time-varying arrival rate

NASA Technical Reports Server (NTRS)

Cassandras, Christos G.; Pan, Jie

1991-01-01

The authors consider an M/G/1 queuing with a time-varying arrival rate. The objective is to obtain infinitesimal perturbation analysis (IPA) gradient estimates for various performance measures of interest with respect to certain system parameters. In particular, the authors consider the mean system time over n arrivals and an arrival rate alternating between two values. By choosing a convenient sample path representation of this system, they derive an unbiased IPA gradient estimator which, however, is not consistent, and investigate the nature of this problem.

Numerical modeling of rapidly varying flows using HEC-RAS and WSPG models.

PubMed

Rao, Prasada; Hromadka, Theodore V

2016-01-01

The performance of two popular hydraulic models (HEC-RAS and WSPG) for modeling hydraulic jump in an open channel is investigated. The numerical solutions are compared with a new experimental data set obtained for varying channel bottom slopes and flow rates. Both the models satisfactorily predict the flow depths and location of the jump. The end results indicate that the numerical models output is sensitive to the value of chosen roughness coefficient. For this application, WSPG model is easier to implement with few input variables.

Efficient Encoding and Rendering of Time-Varying Volume Data

NASA Technical Reports Server (NTRS)

Ma, Kwan-Liu; Smith, Diann; Shih, Ming-Yun; Shen, Han-Wei

1998-01-01

Visualization of time-varying volumetric data sets, which may be obtained from numerical simulations or sensing instruments, provides scientists insights into the detailed dynamics of the phenomenon under study. This paper describes a coherent solution based on quantization, coupled with octree and difference encoding for visualizing time-varying volumetric data. Quantization is used to attain voxel-level compression and may have a significant influence on the performance of the subsequent encoding and visualization steps. Octree encoding is used for spatial domain compression, and difference encoding for temporal domain compression. In essence, neighboring voxels may be fused into macro voxels if they have similar values, and subtrees at consecutive time steps may be merged if they are identical. The software rendering process is tailored according to the tree structures and the volume visualization process. With the tree representation, selective rendering may be performed very efficiently. Additionally, the I/O costs are reduced. With these combined savings, a higher level of user interactivity is achieved. We have studied a variety of time-varying volume datasets, performed encoding based on data statistics, and optimized the rendering calculations wherever possible. Preliminary tests on workstations have shown in many cases tremendous reduction by as high as 90% in both storage space and inter-frame delay.

Learning the Value of Money from Stochastically Varying Prices

ERIC Educational Resources Information Center

Garling, Tommy; Gamble, Amelie; Juliusson, Asgeir

2007-01-01

In 3 experiments, the authors investigated learning of the value of money from product prices in an unfamiliar currency when the prices are proportional to quantity. In support of the second stage of a hypothesized 2-stage process of learning, Experiment 1, in which 32 undergraduates participated, shows that response times for inferences of…

Comparison of NDVI fields obtained from different remote sensors

NASA Astrophysics Data System (ADS)

Escribano Rodriguez, Juan; Alonso, Carmelo; Tarquis, Ana Maria; Benito, Rosa Maria; Hernandez Díaz-Ambrona, Carlos

2013-04-01

Satellite image data have become an important source of information for monitoring vegetation and mapping land cover at several scales. Beside this, the distribution and phenology of vegetation is largely associated with climate, terrain characteristics and human activity. Various vegetation indices have been developed for qualitative and quantitative assessment of vegetation using remote spectral measurements. In particular, sensors with spectral bands in the red (RED) and near-infrared (NIR) lend themselves well to vegetation monitoring and based on them [(NIR - RED) / (NIR + RED)] Normalized Difference Vegetation Index (NDVI) has been widespread used. Given that the characteristics of spectral bands in RED and NIR vary distinctly from sensor to sensor, NDVI values based on data from different instruments will not be directly comparable. The spatial resolution also varies significantly between sensors, as well as within a given scene in the case of wide-angle and oblique sensors. As a result, NDVI values will vary according to combinations of the heterogeneity and scale of terrestrial surfaces and pixel footprint sizes. Therefore, the question arises as to the impact of differences in spectral and spatial resolutions on vegetation indices like the NDVI and their interpretation as a drought index. During 2012 three locations (at Salamanca, Granada and Córdoba) were selected and a periodic pasture monitoring and botanic composition were achieved. Daily precipitation, temperature and monthly soil water content were measurement as well as fresh and dry pasture weight. At the same time, remote sensing images were capture by DEIMOS-1 and MODIS of the chosen places. DEIMOS-1 is based on the concept Microsat-100 from Surrey. It is conceived for obtaining Earth images with a good enough resolution to study the terrestrial vegetation cover (20x20 m), although with a great range of visual field (600 km) in order to obtain those images with high temporal resolution and at a

Mapping Bone Mineral Density Obtained by Quantitative Computed Tomography to Bone Volume Fraction

NASA Technical Reports Server (NTRS)

Pennline, James A.; Mulugeta, Lealem

2017-01-01

Methods for relating or mapping estimates of volumetric Bone Mineral Density (vBMD) obtained by Quantitative Computed Tomography to Bone Volume Fraction (BVF) are outlined mathematically. The methods are based on definitions of bone properties, cited experimental studies and regression relations derived from them for trabecular bone in the proximal femur. Using an experimental range of values in the intertrochanteric region obtained from male and female human subjects, age 18 to 49, the BVF values calculated from four different methods were compared to the experimental average and numerical range. The BVF values computed from the conversion method used data from two sources. One source provided pre bed rest vBMD values in the intertrochanteric region from 24 bed rest subject who participated in a 70 day study. Another source contained preflight vBMD values from 18 astronauts who spent 4 to 6 months on the ISS. To aid the use of a mapping from BMD to BVF, the discussion includes how to formulate them for purpose of computational modeling. An application of the conversions would be used to aid in modeling of time varying changes in vBMD as it relates to changes in BVF via bone remodeling and/or modeling.

The asymmetry of U.S. monetary policy: Evidence from a threshold Taylor rule with time-varying threshold values

NASA Astrophysics Data System (ADS)

Zhu, Yanli; Chen, Haiqiang

2017-05-01

In this paper, we revisit the issue whether U.S. monetary policy is asymmetric by estimating a forward-looking threshold Taylor rule with quarterly data from 1955 to 2015. In order to capture the potential heterogeneity for regime shift mechanism under different economic conditions, we modify the threshold model by assuming the threshold value as a latent variable following an autoregressive (AR) dynamic process. We use the unemployment rate as the threshold variable and separate the sample into two periods: expansion periods and recession periods. Our findings support that the U.S. monetary policy operations are asymmetric in these two regimes. More precisely, the monetary authority tends to implement an active Taylor rule with a weaker response to the inflation gap (the deviation of inflation from its target) and a stronger response to the output gap (the deviation of output from its potential level) in recession periods. The threshold value, interpreted as the targeted unemployment rate of monetary authorities, exhibits significant time-varying properties, confirming the conjecture that policy makers may adjust their reference point for the unemployment rate accordingly to reflect their attitude on the health of general economy.

Investigation of Three Analytical Hypothesis for Determining Material Creep Behavior under Varied Loads, with an Application to 2024-T3 Aluminum-Alloy Sheet in Tension at 400 F

NASA Technical Reports Server (NTRS)

Berkovits, Avraham

1961-01-01

Three existing hypotheses are formulated mathematically to estimate tensile creep strain under varied loads and constant temperature from creep data obtained under constant load and constant temperature. hypotheses investigated include the time-hardening, strain-hardening, and life-fraction rules. Predicted creep behavior is compared with data obtained from tensile creep tests of 2024-T3 aluminum-alloy sheet at 400 F under cyclic-load conditions. creep strain under varied loads is presented on the basis of an equivalent stress, derived from the life-fraction rule, which reduces the varied-load case to a constant-load problem. Creep strain in the region of interest for structural design and rupture times, determined from the hypotheses investigated, are in fair agreement with data in most cases, although calculated values of creep strain are generally greater than the experimental values because creep recovery is neglected in the calculations.

Time-varying q-deformed dark energy interacts with dark matter

NASA Astrophysics Data System (ADS)

Dil, Emre; Kolay, Erdinç

We propose a new model for studying the dark constituents of the universe by regarding the dark energy as a q-deformed scalar field interacting with the dark matter, in the framework of standard general relativity. Here we assume that the number of particles in each mode of the q-deformed scalar field varies in time by the particle creation and annihilation. We first describe the q-deformed scalar field dark energy quantum-field theoretically, then construct the action and the dynamical structure of these interacting dark sectors, in order to study the dynamics of the model. We perform the phase space analysis of the model to confirm and interpret our proposal by searching the stable attractor solutions implying the late-time accelerating phase of the universe. We then obtain the result that when interaction and equation-of-state parameter of the dark matter evolve from the present day values into a particular value, the dark energy turns out to be a q-deformed scalar field.

7 CFR 356.4 - Property valued at $10,000 or less; notice of seizure administrative action to obtain forfeiture.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 5 2012-01-01 2012-01-01 false Property valued at $10,000 or less; notice of seizure administrative action to obtain forfeiture. 356.4 Section 356.4 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FORFEITURE...

Obtaining Magnetic Properties of Meteorites Using Magnetic Scanner

NASA Astrophysics Data System (ADS)

Kletetschka, G.; Nabelek, L.; Mazanec, M.; Simon, K.; Hruba, J.

2015-12-01

Magnetic images of Murchison meteorite's and Chelyabinsk meteorite's thin section have been obtained from magnetic scanning system from Youngwood Science and Engineering (YSE) capable of resolving magnetic anomalies down to 10-3 mT range from about 0.3 mm distance between the probe and meteorite surface (resolution about 0.15 mm). Anomalies were produced repeatedly, each time after application of magnetic field pulse of varying amplitude and constant, normal or reversed, direction. This process resulted in both magnetizing and demagnetizing of the meteorite thin section, while keeping the magnetization vector in the plane of the thin section. Analysis of the magnetic data allows determination of coercivity of remanence (Bcr) for the magnetic sources in situ. Value of Bcr is critical for calculating magnetic forces applicable during missions to asteroids where gravity is compromised. Bcr was estimated by two methods. First method measured varying dipole magnetic field strength produced by each anomaly in the direction of magnetic pulses. Second method measured deflections of the dipole direction from the direction of magnetic pulses (Nabelek et al., 2015). Nabelek, L., Mazanec, M., Kdyr, S., and Kletetschka, G., 2015, Magnetic, in situ, mineral characterization of Chelyabinsk meteorite thin section: Meteoritics & Planetary Science.

Passivity analysis of memristor-based impulsive inertial neural networks with time-varying delays.

PubMed

Wan, Peng; Jian, Jigui

2018-03-01

This paper focuses on delay-dependent passivity analysis for a class of memristive impulsive inertial neural networks with time-varying delays. By choosing proper variable transformation, the memristive inertial neural networks can be rewritten as first-order differential equations. The memristive model presented here is regarded as a switching system rather than employing the theory of differential inclusion and set-value map. Based on matrix inequality and Lyapunov-Krasovskii functional method, several delay-dependent passivity conditions are obtained to ascertain the passivity of the addressed networks. In addition, the results obtained here contain those on the passivity for the addressed networks without impulse effects as special cases and can also be generalized to other neural networks with more complex pulse interference. Finally, one numerical example is presented to show the validity of the obtained results. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Estimating varying coefficients for partial differential equation models.

PubMed

Zhang, Xinyu; Cao, Jiguo; Carroll, Raymond J

2017-09-01

Partial differential equations (PDEs) are used to model complex dynamical systems in multiple dimensions, and their parameters often have important scientific interpretations. In some applications, PDE parameters are not constant but can change depending on the values of covariates, a feature that we call varying coefficients. We propose a parameter cascading method to estimate varying coefficients in PDE models from noisy data. Our estimates of the varying coefficients are shown to be consistent and asymptotically normally distributed. The performance of our method is evaluated by a simulation study and by an empirical study estimating three varying coefficients in a PDE model arising from LIDAR data. © 2017, The International Biometric Society.

Assessment of the radionuclide angiographic left ventricular maximum time-varying elastance calculation in man.

PubMed

Starling, M R; Gross, M D; Walsh, R A; Dell'Italia, L J; Montgomery, D G; Squicciarini, S A; Blumhardt, R

1988-08-01

This investigation was designed to determine whether left ventricular (LV) maximum time-varying elastance (Emax) calculations obtained using equilibrium radionuclide angiography (RNA) were comparable to those obtained using biplane contrast cineangiography (CINE), and whether simple, indirect P-V relations might provide reasonable, alternative estimates of Emax. Accordingly, we studied 19 patients with simultaneous high-fidelity micromanometer LV and fluid brachial artery (Ba) pressure recordings, CINE, and RNA under control conditions and during methoxamine and nitroprusside infusions. Emax was defined for CINE and RNA as the maximum slope of the linear relation of isochronal, instantaneous P-V data points obtained from each of the three loading conditions. The indirect P-V relations were similarly obtained from Ba peak (P) pressure versus minimum RNA LV volume (BaP/minV) and Ba dicrotic notch (di) pressure versus minimum RNA LV volume (Badi/minV) data points. The mean heart rates and LV (+)dP/dtmax values were minimally altered during the three loading conditions. The isochronal Emax values ranged from 1.40 to 6.73 mmHg/ml (mean 4.13 +/- 1.99 s.d. mmHg/ml) for CINE and from 1.48 to 7.25 (mean 4.35 +/- 1.81 mmHg/ml) for RNA (p = N.S.). Similarly, the unstressed volumes ranged from -10 to 80 ml (mean 30 +/- 23 ml) for CINE and from -8 to 77 ml (29 +/- 21 ml) for RNA (p = N.S.). The individual, isochronal Emax values by RNA correlated with those by CINE (r = 0.86). In 14 of the 19 patients, the BaP/minV and Badi/minV relations correlated with the isochronal Emax values calculated by RNA (r = 0.83 and 0.82, respectively), and these relations also correlated with the Emax values calculated by CINE (r = 0.82 and 0.78, respectively). The slope and V0 values for the BaP/minV and Badi/minV relations underestimated those for Emax by RNA and CINE (p less than 0.01 and p less than 0.05, respectively, for both). Thus, the isochronal Emax values calculated using RNA are

Utilization of coffee by-products obtained from semi-washed process for production of value-added compounds.

PubMed

Bonilla-Hermosa, Verónica Alejandra; Duarte, Whasley Ferreira; Schwan, Rosane Freitas

2014-08-01

The semi-dry processing of coffee generates significant amounts of coffee pulp and wastewater. This study evaluated the production of bioethanol and volatile compounds of eight yeast strains cultivated in a mixture of these residues. Hanseniaspora uvarum UFLA CAF76 showed the best fermentation performance; hence it was selected to evaluate different culture medium compositions and inoculum size. The best results were obtained with 12% w/v of coffee pulp, 1 g/L of yeast extract and 0.3 g/L of inoculum. Using these conditions, fermentation in 1 L of medium was carried out, achieving higher ethanol yield, productivity and efficiency with values of 0.48 g/g, 0.55 g/L h and 94.11% respectively. Twenty-one volatile compounds corresponding to higher alcohols, acetates, terpenes, aldehydes and volatile acids were identified by GC-FID. Such results indicate that coffee residues show an excellent potential as substrates for production of value-added compounds. H. uvarum demonstrated high fermentative capacity using these residues. Copyright © 2014 Elsevier Ltd. All rights reserved.

7 CFR 356.3 - Property valued at greater than $10,000; notice of seizure and civil action to obtain forfeiture.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 5 2012-01-01 2012-01-01 false Property valued at greater than $10,000; notice of seizure and civil action to obtain forfeiture. 356.3 Section 356.3 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

The Defense Logistics Agency Properly Awarded Power Purchase Agreements and the Army Obtained Fair Market Value for Leases Supporting Power Purchase Agreements

DTIC Science & Technology

2016-09-28

Fair Market Value for Leases Supporting Power Purchase Agreements I N T E G R I T Y  E F F I C I E N C Y  A C C O U N T A B I L I T Y  E X... Market Value for Leases Supporting Power Purchase Agreements Visit us at www.dodig.mil September 28, 2016 Objective We determined whether the...Department of the Army properly awarded and obtained fair market value for leases supporting energy production projects. We conducted this audit in

Comparison of fractal dimensions based on segmented NDVI fields obtained from different remote sensors.

NASA Astrophysics Data System (ADS)

Alonso, C.; Benito, R. M.; Tarquis, A. M.

2012-04-01

such complexities from remote sensing images and will applied in this study to see the scaling behavior for each sensor in generalized fractal dimensions. The studied area is located in the provinces of Caceres and Salamanca (east of Iberia Peninsula) with an extension of 32 x 32 km2. The altitude in the area varies from 1,560 to 320 m, comprising natural vegetation in the mountain area (forest and bushes) and agricultural crops in the valleys. Scaling analysis were applied to Landsat-5 and MODIS TERRA to the normalized derived vegetation index (NDVI) on the same region with one day of difference, 13 and 12 of July 2003 respectively. From these images the area of interest was selected obtaining 1024 x 1024 pixels for Landsat image and 128 x 128 pixels for MODIS image. This implies that the resolution for MODIS is 250x250 m. and for Landsat is 30x30 m. From the reflectance data obtained from NIR and RED bands, NDVI was calculated for each image focusing this study on 0.2 to 0.5 ranges of values. Once that both NDVI fields were obtained several fractal dimensions were estimated in each one segmenting the values in 0.20-0.25, 0.25-0.30 and so on to rich 0.45-0.50. In all the scaling analysis the scale size length was expressed in meters, and not in pixels, to make the comparison between both sensors possible. Results are discussed. Acknowledgements This work has been supported by the Spanish MEC under Projects No. AGL2010-21501/AGR, MTM2009-14621 and i-MATH No. CSD2006-00032

Magnetization Switching of a Co /Pt Multilayered Perpendicular Nanomagnet Assisted by a Microwave Field with Time-Varying Frequency

NASA Astrophysics Data System (ADS)

Suto, Hirofumi; Kanao, Taro; Nagasawa, Tazumi; Mizushima, Koichi; Sato, Rie

2018-05-01

Microwave-assisted magnetization switching (MAS) is attracting attention as a method for reversing nanomagnets with a high magnetic anisotropy by using a small-amplitude magnetic field. We experimentally study MAS of a perpendicularly magnetized nanomagnet by applying a microwave magnetic field with a time-varying frequency. Because the microwave field frequency can follow the nonlinear decrease of the resonance frequency, larger magnetization excitation than that in a constant-frequency microwave field is induced, which enhances the MAS effect. The switching field decreases almost linearly as the start value of the time-varying microwave field frequency increases, and it becomes smaller than the minimum switching field in a constant-frequency microwave field. To obtain this enhancement of the MAS effect, the end value of the time-varying microwave field frequency needs to be almost the same as or lower than the critical frequency for MAS in a constant-frequency microwave field. In addition, the frequency change typically needs to take 1 ns or longer to make the rate of change slow enough for the magnetization to follow the frequency change. This switching behavior is qualitatively explained by the theory based on the macrospin model.

Value Representations by Rank Order in a Distributed Network of Varying Context Dependency

ERIC Educational Resources Information Center

Mullett, Timothy L.; Tunney, Richard J.

2013-01-01

We report the results of a human fMRI experiment investigating the influence of context upon value judgement. Trials were separated into high and low value blocks such that it is possible to investigate the effect of a change in surrounding trials upon the encoding of financial value. The ventral striatum was dependent upon "local context", with…

Robustness analysis of multirate and periodically time varying systems

NASA Technical Reports Server (NTRS)

Berg, Martin C.; Mason, Gregory S.

1991-01-01

A new method for analyzing the stability and robustness of multirate and periodically time varying systems is presented. It is shown that a multirate or periodically time varying system can be transformed into an equivalent time invariant system. For a SISO system, traditional gain and phase margins can be found by direct application of the Nyquist criterion to this equivalent time invariant system. For a MIMO system, structured and unstructured singular values can be used to determine the system's robustness. The limitations and implications of utilizing this equivalent time invariant system for calculating gain and phase margins, and for estimating robustness via singular value analysis are discussed.

Estimating inbreeding in large, semi-isolated populations: effects of varying generation lengths and of migration.

PubMed

Pattison, J E

2007-01-01

The purpose of the study reported here was to investigate two important assumptions used in a recently reported new method of estimating inbreeding in large, relatively isolated populations over historic times. The method, based on modeling the genealogical "paradox," produces values of Pearl's coefficients, Z, a measure of inbreeding or genealogical coalescence, as a function of time. In this study, the effects on inbreeding of two important assumptions made in earlier studies, namely those of using a constant generation length and of ignoring migration, have been investigated for the population of Britain. First, by relating the median age of women at childbirth to the development level of various societies, the variation of the generation lengths for different periods in historic Britain were estimated. Values of Z for two types of varying generation lengths were then calculated and compared with the case of constant generation length. Second, the population curve for Britain used in earlier studies was modified to obtain the subpopulation at any time during the past two millennia that was descended from the pre-Roman British Celts. Values of Z for the case with migration were then calculated and compared with the case for no migration. It is shown that these two assumptions may be taken into account if and when required. Both the effect of a varying generation length and the effect of migration on Z were found to be 20-40%, when no known value of inbreeding was used, and 2-5%, when a known value of inbreeding was used.

Value of Defect Information in Automated Hardwood Edger and Trimmer Systems

Treesearch

Carmen Regalado; D. Earl Kline; Philip A. Araman

1992-01-01

Due to the limited capability of board defect scanners, not all defect information required to make the best edging and trimming decision can be scanned for use in an automated system. The objective of the study presented in this paper was to evaluate the lumber value obtainable from edging and trimming optimization using varying levels of defect information as input....

Hydraulic properties of fronds from palms of varying height and habitat.

PubMed

Renninger, Heidi J; Phillips, Nathan

2011-12-01

Because palms grow in highly varying climates and reach considerable heights, they present a unique opportunity to evaluate how environment and plant size impact hydraulic function. We studied hydraulic properties of petioles from palms of varying height from three species: Iriartea deltoidea, a tropical rainforest species; Mauritia flexuosa, a tropical rainforest, swamp species; and Washingtonia robusta, a subtropical species. We measured leaf areas, petiole cross-sectional areas, specific conductivity (K(S)), petiole anatomical properties, vulnerability to embolism and leaf water potentials and calculated petiole Huber values and leaf-specific conductivities (K(L)). Leaf and petiole cross-sectional areas varied widely with height. However, hydraulic properties including Huber values, K(S) and K(L), remained constant. The two palmate species, M. flexuosa and W. robusta, had larger Huber values than I. deltoidea, a pinnately-compound species which exhibited the highest K(S). Metaxylem vessel diameters and vascular bundle densities varied with height in opposing patterns to maintain petiole conductivities. I. deltoidea and W. robusta petioles had similar P(50) values (the point at which 50% of hydraulic conductivity is lost) averaged over all crown heights, but W. robusta exhibited more negative P(50) values in taller palms. Comparison of P (50) values with transpiring midday leaf water potentials, as well as a double-dye staining experiment in a 1-m-tall palm, suggested that a fairly significant amount of embolisms were occurring and refilled on a diurnal basis. Therefore, across palms differing widely in height and growing environments, we found convergence in water transport per unit leaf area (K(L)) with individuals exhibiting differing strategies for achieving this.

Efficiency at maximum power for an isothermal chemical engine with particle exchange at varying chemical potential

NASA Astrophysics Data System (ADS)

Koning, Jesper; Koga, Kenichiro; Indekeu, Joseph. O.

2017-02-01

We calculate the efficiency at maximum power (EMP) of an isothermal chemical cycle in which particle uptake occurs at a fixed chemical potential but particle release takes place at varying chemical potential. We obtain the EMP as a function of Δμ/ kT, where Δμ is the difference between the highest and lowest reservoir chemical potentials and T is the absolute temperature. In the linear response limit, Δμ ≪ kT, the EMP tends to the expected universal value 1/2.

Master-slave exponential synchronization of delayed complex-valued memristor-based neural networks via impulsive control.

PubMed

Li, Xiaofan; Fang, Jian-An; Li, Huiyuan

2017-09-01

This paper investigates master-slave exponential synchronization for a class of complex-valued memristor-based neural networks with time-varying delays via discontinuous impulsive control. Firstly, the master and slave complex-valued memristor-based neural networks with time-varying delays are translated to two real-valued memristor-based neural networks. Secondly, an impulsive control law is constructed and utilized to guarantee master-slave exponential synchronization of the neural networks. Thirdly, the master-slave synchronization problems are transformed into the stability problems of the master-slave error system. By employing linear matrix inequality (LMI) technique and constructing an appropriate Lyapunov-Krasovskii functional, some sufficient synchronization criteria are derived. Finally, a numerical simulation is provided to illustrate the effectiveness of the obtained theoretical results. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Value of Information for Populations in Varying Environments

NASA Astrophysics Data System (ADS)

Rivoire, Olivier; Leibler, Stanislas

2011-04-01

The notion of information pervades informal descriptions of biological systems, but formal treatments face the problem of defining a quantitative measure of information rooted in a concept of fitness, which is itself an elusive notion. Here, we present a model of population dynamics where this problem is amenable to a mathematical analysis. In the limit where any information about future environmental variations is common to the members of the population, our model is equivalent to known models of financial investment. In this case, the population can be interpreted as a portfolio of financial assets and previous analyses have shown that a key quantity of Shannon's communication theory, the mutual information, sets a fundamental limit on the value of information. We show that this bound can be violated when accounting for features that are irrelevant in finance but inherent to biological systems, such as the stochasticity present at the individual level. This leads us to generalize the measures of uncertainty and information usually encountered in information theory.

Microwave fidelity studies by varying antenna coupling

NASA Astrophysics Data System (ADS)

Köber, B.; Kuhl, U.; Stöckmann, H.-J.; Gorin, T.; Savin, D. V.; Seligman, T. H.

2010-09-01

The fidelity decay in a microwave billiard is considered, where the coupling to an attached antenna is varied. The resulting quantity, coupling fidelity, is experimentally studied for three different terminators of the varied antenna: a hard-wall reflection, an open wall reflection, and a 50Ω load, corresponding to a totally open channel. The model description in terms of an effective Hamiltonian with a complex coupling constant is given. Quantitative agreement is found with the theory obtained from a modified VWZ approach [J. J. M. Verbaarschot , Phys. Rep. 129, 367 (1985)10.1016/0370-1573(85)90070-5].

Remote measurement of water color in coastal waters. [spectral radiance data used to obtain quantitative values for chlorophyll and turbidity

NASA Technical Reports Server (NTRS)

Weldon, J. W.

1973-01-01

An investigation was conducted to develop procedure to obtain quantitative values for chlorophyll and turbidity in coastal waters by observing the changes in spectral radiance of the backscattered spectrum. The technique under consideration consists of Examining Exotech model 20-D spectral radiometer data and determining which radiance ratios best correlated with chlorophyll and turbidity measurements as obtained from analyses of water samples and sechi visibility readings. Preliminary results indicate that there is a correlation between backscattered light and chlorophyll concentration and secchi visibility. The tests were conducted with the spectrometer mounted in a light aircraft over the Mississippi Sound at altitudes of 2.5K, 2.8K and 10K feet.

Stability of Nonlinear Systems with Unknown Time-varying Feedback Delay

NASA Astrophysics Data System (ADS)

Chunodkar, Apurva A.; Akella, Maruthi R.

2013-12-01

This paper considers the problem of stabilizing a class of nonlinear systems with unknown bounded delayed feedback wherein the time-varying delay is 1) piecewise constant 2) continuous with a bounded rate. We also consider application of these results to the stabilization of rigid-body attitude dynamics. In the first case, the time-delay in feedback is modeled specifically as a switch among an arbitrarily large set of unknown constant values with a known strict upper bound. The feedback is a linear function of the delayed states. In the case of linear systems with switched delay feedback, a new sufficiency condition for average dwell time result is presented using a complete type Lyapunov-Krasovskii (L-K) functional approach. Further, the corresponding switched system with nonlinear perturbations is proven to be exponentially stable inside a well characterized region of attraction for an appropriately chosen average dwell time. In the second case, the concept of the complete type L-K functional is extended to a class of nonlinear time-delay systems with unknown time-varying time-delay. This extension ensures stability robustness to time-delay in the control design for all values of time-delay less than the known upper bound. Model-transformation is used in order to partition the nonlinear system into a nominal linear part that is exponentially stable with a bounded perturbation. We obtain sufficient conditions which ensure exponential stability inside a region of attraction estimate. A constructive method to evaluate the sufficient conditions is presented together with comparison with the corresponding constant and piecewise constant delay. Numerical simulations are performed to illustrate the theoretical results of this paper.

Dealing with the time-varying parameter problem of robot manipulators performing path tracking tasks

NASA Technical Reports Server (NTRS)

Song, Y. D.; Middleton, R. H.

1992-01-01

Many robotic applications involve time-varying payloads during the operation of the robot. It is therefore of interest to consider control schemes that deal with time-varying parameters. Using the properties of the element by element (or Hadarmad) product of matrices, we obtain the robot dynamics in parameter-isolated form, from which a new control scheme is developed. The controller proposed yields zero asymptotic tracking errors when applied to robotic systems with time-varying parameters by using a switching type control law. The results obtained are global in the initial state of the robot, and can be applied to rapidly varying systems.

Correlation between the thickness of the crestal and buccolingual cortical bone at varying depths and implant stability quotients

PubMed Central

Chatvaratthana, Kanthanat; Thaworanunta, Sita; Seriwatanachai, Dutmanee; Wongsirichat, Natthamet

2017-01-01

Background/purpose Resonance frequency analysis (RFA) is clinically used in dentistry to access the stiffness of dental implants in surrounding bone. However, the clear advantages and disadvantages of this method are still inconclusive. The aim of this study was to investigate and compare implant stability quotient (ISQ) values obtained from RFA with parameters obtained from a cone beam computed tomography (CBCT) scan of the same region. Materials and methods Nineteen implants (Conelog) were inserted in the posterior maxillary and mandibular partially edentulous regions of 16 patients. At the time of implant placement, the ISQ values were obtained using RFA (Osstell). CBCT was used to measure the thickness of the crestal, cortical, buccolingual cortical, and cancellous bone at 3, 6, and 9 mm below the crestal bone level, as indicated by radiographic markers. The ratio of the thickness of the cortical to cancellous bone at varying depths was also calculated and classified into 4 groups (Group 1–4). Results There was a strong correlation between the crestal cortical bone thickness and ISQ values (P<0.001). The thickness of the buccolingual cortical bone and ratio of the cortical to cancellous bone thickness at 3 mm were significantly related to the ISQ (P = 0.018 and P = 0.034, respectively). Furthermore, the ISQs in Group 1 were the highest compared with those in Group 2 and Group 3, whereas the CBCT parameters at 6 and 9 mm did not have any specific correlation with the ISQ values. Conclusion This study showed that the ISQ values obtained from RFA highly correlated with the quantity and quality of bone 3 mm below the crestal bone level. The correlation between the ISQ and bone surrounding the implant site was dependent on the depth of measurement. Therefore, RFA can help to predict the marginal bone level, as confirmed in this study. PMID:29281715

Mediation analysis with time varying exposures and mediators.

PubMed

VanderWeele, Tyler J; Tchetgen Tchetgen, Eric J

2017-06-01

In this paper we consider causal mediation analysis when exposures and mediators vary over time. We give non-parametric identification results, discuss parametric implementation, and also provide a weighting approach to direct and indirect effects based on combining the results of two marginal structural models. We also discuss how our results give rise to a causal interpretation of the effect estimates produced from longitudinal structural equation models. When there are time-varying confounders affected by prior exposure and mediator, natural direct and indirect effects are not identified. However, we define a randomized interventional analogue of natural direct and indirect effects that are identified in this setting. The formula that identifies these effects we refer to as the "mediational g-formula." When there is no mediation, the mediational g-formula reduces to Robins' regular g-formula for longitudinal data. When there are no time-varying confounders affected by prior exposure and mediator values, then the mediational g-formula reduces to a longitudinal version of Pearl's mediation formula. However, the mediational g-formula itself can accommodate both mediation and time-varying confounders and constitutes a general approach to mediation analysis with time-varying exposures and mediators.

Optimization of hydrostatic pressure at varied sonication conditions--power density, intensity, very low frequency--for isothermal ultrasonic sludge treatment.

PubMed

Delmas, Henri; Le, Ngoc Tuan; Barthe, Laurie; Julcour-Lebigue, Carine

2015-07-01

This work aims at investigating for the first time the key sonication (US) parameters: power density (DUS), intensity (IUS), and frequency (FS) - down to audible range, under varied hydrostatic pressure (Ph) and low temperature isothermal conditions (to avoid any thermal effect). The selected application was activated sludge disintegration, a major industrial US process. For a rational approach all comparisons were made at same specific energy input (ES, US energy per solid weight) which is also the relevant economic criterion. The decoupling of power density and intensity was obtained by either changing the sludge volume or most often by changing probe diameter, all other characteristics being unchanged. Comprehensive results were obtained by varying the hydrostatic pressure at given power density and intensity. In all cases marked maxima of sludge disintegration appeared at optimum pressures, which values increased at increasing power intensity and density. Such optimum was expected due to opposite effects of increasing hydrostatic pressure: higher cavitation threshold then smaller and fewer bubbles, but higher temperature and pressure at the end of collapse. In addition the first attempt to lower US frequency down to audible range was very successful: at any operation condition (DUS, IUS, Ph, sludge concentration and type) higher sludge disintegration was obtained at 12 kHz than at 20 kHz. The same values of optimum pressure were observed at 12 and 20 kHz. At same energy consumption the best conditions - obtained at 12 kHz, maximum power density 720 W/L and 3.25 bar - provided about 100% improvement with respect to usual conditions (1 bar, 20 kHz). Important energy savings and equipment size reduction may then be expected. Copyright © 2014 Elsevier B.V. All rights reserved.

Yellow-poplar seed quality varies by seed trees, stands, and years

Treesearch

G.A. Limstrom

1959-01-01

The number of year-old yellow-poplar (Liriodendron tulipifera L.) seedlings grown from equal quantities of seed varies as much among individual seed trees within a stand as among stands of different geographic location. Moreover, production will vary from one year to another. This information was obtained from an experiment begun in the Central...

A hierarchical nest survival model integrating incomplete temporally varying covariates

PubMed Central

Converse, Sarah J; Royle, J Andrew; Adler, Peter H; Urbanek, Richard P; Barzen, Jeb A

2013-01-01

Nest success is a critical determinant of the dynamics of avian populations, and nest survival modeling has played a key role in advancing avian ecology and management. Beginning with the development of daily nest survival models, and proceeding through subsequent extensions, the capacity for modeling the effects of hypothesized factors on nest survival has expanded greatly. We extend nest survival models further by introducing an approach to deal with incompletely observed, temporally varying covariates using a hierarchical model. Hierarchical modeling offers a way to separate process and observational components of demographic models to obtain estimates of the parameters of primary interest, and to evaluate structural effects of ecological and management interest. We built a hierarchical model for daily nest survival to analyze nest data from reintroduced whooping cranes (Grus americana) in the Eastern Migratory Population. This reintroduction effort has been beset by poor reproduction, apparently due primarily to nest abandonment by breeding birds. We used the model to assess support for the hypothesis that nest abandonment is caused by harassment from biting insects. We obtained indices of blood-feeding insect populations based on the spatially interpolated counts of insects captured in carbon dioxide traps. However, insect trapping was not conducted daily, and so we had incomplete information on a temporally variable covariate of interest. We therefore supplemented our nest survival model with a parallel model for estimating the values of the missing insect covariates. We used Bayesian model selection to identify the best predictors of daily nest survival. Our results suggest that the black fly Simulium annulus may be negatively affecting nest survival of reintroduced whooping cranes, with decreasing nest survival as abundance of S. annulus increases. The modeling framework we have developed will be applied in the future to a larger data set to evaluate the

A hierarchical nest survival model integrating incomplete temporally varying covariates

USGS Publications Warehouse

Converse, Sarah J.; Royle, J. Andrew; Adler, Peter H.; Urbanek, Richard P.; Barzan, Jeb A.

2013-01-01

Nest success is a critical determinant of the dynamics of avian populations, and nest survival modeling has played a key role in advancing avian ecology and management. Beginning with the development of daily nest survival models, and proceeding through subsequent extensions, the capacity for modeling the effects of hypothesized factors on nest survival has expanded greatly. We extend nest survival models further by introducing an approach to deal with incompletely observed, temporally varying covariates using a hierarchical model. Hierarchical modeling offers a way to separate process and observational components of demographic models to obtain estimates of the parameters of primary interest, and to evaluate structural effects of ecological and management interest. We built a hierarchical model for daily nest survival to analyze nest data from reintroduced whooping cranes (Grus americana) in the Eastern Migratory Population. This reintroduction effort has been beset by poor reproduction, apparently due primarily to nest abandonment by breeding birds. We used the model to assess support for the hypothesis that nest abandonment is caused by harassment from biting insects. We obtained indices of blood-feeding insect populations based on the spatially interpolated counts of insects captured in carbon dioxide traps. However, insect trapping was not conducted daily, and so we had incomplete information on a temporally variable covariate of interest. We therefore supplemented our nest survival model with a parallel model for estimating the values of the missing insect covariates. We used Bayesian model selection to identify the best predictors of daily nest survival. Our results suggest that the black fly Simulium annulus may be negatively affecting nest survival of reintroduced whooping cranes, with decreasing nest survival as abundance of S. annulus increases. The modeling framework we have developed will be applied in the future to a larger data set to evaluate the

The economic value of an investment in physiotherapy education: a net present value analysis.

PubMed

Rivers, George; Foo, Jonathan; Ilic, Dragan; Nicklen, Peter; Reeves, Scott; Walsh, Kieran; Maloney, Stephen

2015-07-01

What is the economic value for an individual to invest in physiotherapy undergraduate education in Australia? How is this affected by increased education costs or decreased wages? A cost-benefit analysis using a net present value (NPV) approach was conducted and reported in Australian dollars. In relation to physiotherapy education, the NPV represents future earnings as a physiotherapist minus the direct and indirect costs in obtaining the degree. Sensitivity analyses were conducted to consider varying levels of experience, public versus private sector, and domestic versus international student fees. Comparable calculations were made for educational investments in medicine and nursing/midwifery. Assuming an expected discount rate of 9.675%, investment in education by domestic students with approximately 34 years of average work experience yields a NPV estimated at $784,000 for public sector physiotherapists and $815,000 for private sector therapists. In relation to international students, the NPV results for an investment and career as a physiotherapist is estimated at $705,000 in the public sector and $736,000 in the private sector. With an approximate payback period of 4 years, coupled with strong and positive NPV values, physiotherapy education in Australia is a financially attractive prospect and a viable value proposition for those considering a career in this field. Copyright © 2015 Australian Physiotherapy Association. Published by Elsevier B.V. All rights reserved.

Observational constraints on holographic dark energy with varying gravitational constant

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

Lu, Jianbo; Xu, Lixin; Saridakis, Emmanuel N.

2010-03-01

We use observational data from Type Ia Supernovae (SN), Baryon Acoustic Oscillations (BAO), Cosmic Microwave Background (CMB) and observational Hubble data (OHD), and the Markov Chain Monte Carlo (MCMC) method, to constrain the cosmological scenario of holographic dark energy with varying gravitational constant. We consider both flat and non-flat background geometry, and we present the corresponding constraints and contour-plots of the model parameters. We conclude that the scenario is compatible with observations. In 1σ we find Ω{sub Λ0} = 0.72{sup +0.03}{sub −0.03}, Ω{sub k0} = −0.0013{sup +0.0130}{sub −0.0040}, c = 0.80{sup +0.19}{sub −0.14} and Δ{sub G}≡G'/G = −0.0025{sup +0.0080}{sub −0.0050},more » while for the present value of the dark energy equation-of-state parameter we obtain w{sub 0} = −1.04{sup +0.15}{sub −0.20}.« less

Isosurface Extraction in Time-Varying Fields Using a Temporal Hierarchical Index Tree

NASA Technical Reports Server (NTRS)

Shen, Han-Wei; Gerald-Yamasaki, Michael (Technical Monitor)

1998-01-01

Many high-performance isosurface extraction algorithms have been proposed in the past several years as a result of intensive research efforts. When applying these algorithms to large-scale time-varying fields, the storage overhead incurred from storing the search index often becomes overwhelming. this paper proposes an algorithm for locating isosurface cells in time-varying fields. We devise a new data structure, called Temporal Hierarchical Index Tree, which utilizes the temporal coherence that exists in a time-varying field and adoptively coalesces the cells' extreme values over time; the resulting extreme values are then used to create the isosurface cell search index. For a typical time-varying scalar data set, not only does this temporal hierarchical index tree require much less storage space, but also the amount of I/O required to access the indices from the disk at different time steps is substantially reduced. We illustrate the utility and speed of our algorithm with data from several large-scale time-varying CID simulations. Our algorithm can achieve more than 80% of disk-space savings when compared with the existing techniques, while the isosurface extraction time is nearly optimal.

Factors influencing the robustness of P-value measurements in CT texture prognosis studies

NASA Astrophysics Data System (ADS)

McQuaid, Sarah; Scuffham, James; Alobaidli, Sheaka; Prakash, Vineet; Ezhil, Veni; Nisbet, Andrew; South, Christopher; Evans, Philip

2017-07-01

Several studies have recently reported on the value of CT texture analysis in predicting survival, although the topic remains controversial, with further validation needed in order to consolidate the evidence base. The aim of this study was to investigate the effect of varying the input parameters in the Kaplan-Meier analysis, to determine whether the resulting P-value can be considered to be a robust indicator of the parameter’s prognostic potential. A retrospective analysis of the CT-based normalised entropy of 51 patients with lung cancer was performed and overall survival data for these patients were collected. A normalised entropy cut-off was chosen to split the patient cohort into two groups and log-rank testing was performed to assess the survival difference of the two groups. This was repeated for varying normalised entropy cut-offs and varying follow-up periods. Our findings were also compared with previously published results to assess robustness of this parameter in a multi-centre patient cohort. The P-value was found to be highly sensitive to the choice of cut-off value, with small changes in cut-off producing substantial changes in P. The P-value was also sensitive to follow-up period, with particularly noisy results at short follow-up periods. Using matched conditions to previously published results, a P-value of 0.162 was obtained. Survival analysis results can be highly sensitive to the choice in texture cut-off value in dichotomising patients, which should be taken into account when performing such studies to avoid reporting false positive results. Short follow-up periods also produce unstable results and should therefore be avoided to ensure the results produced are reproducible. Previously published findings that indicated the prognostic value of normalised entropy were not replicated here, but further studies with larger patient numbers would be required to determine the cause of the different outcomes.

Value of freedom to choose encoded by the human brain

PubMed Central

Fujiwara, Juri; Usui, Nobuo; Park, Soyoung Q.; Williams, Tony; Iijima, Toshio; Taira, Masato; Tsutsui, Ken-Ichiro

2013-01-01

Humans and animals value the opportunity to choose by preferring alternatives that offer more rather than fewer choices. This preference for choice may arise not only from an increased probability of obtaining preferred outcomes but also from the freedom it provides. We used human neuroimaging to investigate the neural basis of the preference for choice as well as for the items that could be chosen. In each trial, participants chose between two options, a monetary amount option and a “choice option.” The latter consisted of a number that corresponded to the number of everyday items participants would subsequently be able to choose from. We found that the opportunity to choose from a larger number of items was equivalent to greater amounts of money, indicating that participants valued having more choice; moreover, participants varied in the degree to which they valued having the opportunity to choose, with some valuing it more than the increased probability of obtaining preferred items. Neural activations in the mid striatum increased with the value of the opportunity to choose. The same region also coded the value of the items. Conversely, activation in the dorsolateral striatum was not related to the value of the items but was elevated when participants were offered more choices, particularly in those participants who overvalued the opportunity to choose. These data suggest a functional dissociation of value representations within the striatum, with general representations in mid striatum and specific representations of the value of freedom provided by the opportunity to choose in dorsolateral striatum. PMID:23864380

Study on photoemission surface of varied doping GaN photocathode

NASA Astrophysics Data System (ADS)

Qiao, Jianliang; Du, Ruijuan; Ding, Huan; Gao, Youtang; Chang, Benkang

2014-09-01

For varied doping GaN photocathode, from bulk to surface the doping concentrations are distributed from high to low. The varied doping GaN photocathode may produce directional inside electric field within the material, so the higher quantum efficiency can be obtained. The photoemission surface of varied doping GaN photocathode is very important to the high quantum efficiency, but the forming process of the surface state after Cs activation or Cs/O activation has been not known completely. Encircling the photoemission mechanism of varied GaN photocathode, considering the experiment phenomena during the activation and the successful activation results, the varied GaN photocathode surface model [GaN(Mg):Cs]:O-Cs after activation with cesium and oxygen was given. According to GaN photocathode activation process and the change of electronic affinity, the comparatively ideal NEA property can be achieved by Cs or Cs/O activation, and higher quantum efficiency can be obtained. The results show: The effective NEA characteristic of GaN can be gotten only by Cs. [GaN(Mg):Cs] dipoles form the first dipole layer, the positive end is toward the vacuum side. In the activation processing with Cs/O, the second dipole layer is formed by O-Cs dipoles, A O-Cs dipole includes one oxygen atom and two Cs atoms, and the positive end is also toward the vacuum side thus the escape of electrons can be promoted.

Mediation analysis with time varying exposures and mediators

PubMed Central

VanderWeele, Tyler J.; Tchetgen Tchetgen, Eric J.

2016-01-01

Summary In this paper we consider causal mediation analysis when exposures and mediators vary over time. We give non-parametric identification results, discuss parametric implementation, and also provide a weighting approach to direct and indirect effects based on combining the results of two marginal structural models. We also discuss how our results give rise to a causal interpretation of the effect estimates produced from longitudinal structural equation models. When there are time-varying confounders affected by prior exposure and mediator, natural direct and indirect effects are not identified. However, we define a randomized interventional analogue of natural direct and indirect effects that are identified in this setting. The formula that identifies these effects we refer to as the “mediational g-formula.” When there is no mediation, the mediational g-formula reduces to Robins’ regular g-formula for longitudinal data. When there are no time-varying confounders affected by prior exposure and mediator values, then the mediational g-formula reduces to a longitudinal version of Pearl’s mediation formula. However, the mediational g-formula itself can accommodate both mediation and time-varying confounders and constitutes a general approach to mediation analysis with time-varying exposures and mediators. PMID:28824285

Obtaining value prior to pulping with diethyl oxalate and oxalic acid

Treesearch

W.R. Kenealy; E. Horn; C.J. Houtman; J. Laplaza; T.W. Jeffries

2007-01-01

Pulp and paper are converted to paper products with yields of paper dependent on the wood and the process used. Even with high yield pulps there are conversion losses and with chemical pulps the yields approach 50%. The portions of the wood that do not provide product are either combusted to generate power and steam or incur a cost in waste water treatment. Value prior...

Nonlinearly Activated Neural Network for Solving Time-Varying Complex Sylvester Equation.

PubMed

Li, Shuai; Li, Yangming

2013-10-28

The Sylvester equation is often encountered in mathematics and control theory. For the general time-invariant Sylvester equation problem, which is defined in the domain of complex numbers, the Bartels-Stewart algorithm and its extensions are effective and widely used with an O(n³) time complexity. When applied to solving the time-varying Sylvester equation, the computation burden increases intensively with the decrease of sampling period and cannot satisfy continuous realtime calculation requirements. For the special case of the general Sylvester equation problem defined in the domain of real numbers, gradient-based recurrent neural networks are able to solve the time-varying Sylvester equation in real time, but there always exists an estimation error while a recently proposed recurrent neural network by Zhang et al [this type of neural network is called Zhang neural network (ZNN)] converges to the solution ideally. The advancements in complex-valued neural networks cast light to extend the existing real-valued ZNN for solving the time-varying real-valued Sylvester equation to its counterpart in the domain of complex numbers. In this paper, a complex-valued ZNN for solving the complex-valued Sylvester equation problem is investigated and the global convergence of the neural network is proven with the proposed nonlinear complex-valued activation functions. Moreover, a special type of activation function with a core function, called sign-bi-power function, is proven to enable the ZNN to converge in finite time, which further enhances its advantage in online processing. In this case, the upper bound of the convergence time is also derived analytically. Simulations are performed to evaluate and compare the performance of the neural network with different parameters and activation functions. Both theoretical analysis and numerical simulations validate the effectiveness of the proposed method.

84. Mabry Mill. The varying roof lines and siding gives ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

84. Mabry Mill. The varying roof lines and siding gives the mill an interesting texture, increasing its photogenic value. Looking north. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

253. Mabry Mill. The varying roof lines and siding gives ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

253. Mabry Mill. The varying roof lines and siding gives the mill an interesting texture, increasing its photogenic value. Looking north. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

A systematic review of the angular values obtained by computerized photogrammetry in sagittal plane: a proposal for reference values.

PubMed

Krawczky, Bruna; Pacheco, Antonio G; Mainenti, Míriam R M

2014-05-01

Reference values for postural alignment in the coronal plane, as measured by computerized photogrammetry, have been established but not for the sagittal plane. The objective of this study is to propose reference values for angular measurements used for postural analysis in the sagittal plane for healthy adults. Electronic databases (PubMed, BVS, Cochrane, Scielo, and Science Direct) were searched using the following key words: evaluation, posture, photogrammetry, and software. Articles published between 2006 and 2012 that used the PAS/SAPO (postural assessment software) were selected. Another inclusion criterion was the presentation of, at least, one of the following measurements: head horizontal alignment, pelvic horizontal alignment, hip angle, vertical alignment of the body, thoracic kyphosis, and lumbar lordosis. Angle samples of the selected articles were grouped 2 by 2 in relation to an overall average, which made possible total average, variance, and SD calculations. Six articles were included, and the following average angular values were found: 51.42° ± 4.87° (head horizontal alignment), -12.26° ± 5.81° (pelvic horizontal alignment), -6.40° ± 3.86° (hip angle), and 1.73° ± 0.94° (vertical alignment of the body). None of the articles contained the measurements for thoracic kyphosis and lumbar lordosis. The reference values can be adopted as reference for postural assessment in future researches if the same anatomical points are considered. Copyright © 2014 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

[VALUE OF SMART PHONE Scoliometer SOFTWARE IN OBTAINING OPTIMAL LUMBAR LORDOSIS DURING L4-S1 FUSION SURGERY].

PubMed

Yu, Weibo; Liang, De; Ye, Linqiang; Jiang, Xiaobing; Yao, Zhensong; Tang, Jingjing; Tang, Yongchao

2015-10-01

To investigate the value of smart phone Scoliometer software in obtaining optimal lumbar lordosis (LL) during L4-S1 fusion surgery. Between November 2014 and February 2015, 20 patients scheduled for L4-S1 fusion surgery were prospectively enrolled the study. There were 8 males and 12 females, aged 41-65 years (mean, 52.3 years). The disease duration ranged from 6 months to 6 years (mean, 3.4 years). Before operation, the pelvic incidence (PI) and Cobb angle of L4-S1 (CobbL4-S1) were measured on lateral X-ray film of lumbosacral spine by PACS system; and the ideal CobbL4-S1 was then calculated according to previously published methods [(PI+9 degrees) x 70%]. Subsequently, intraoperative CobbL4-S1 was monitored by the Scoliometer software and was defined as optimal while it was less than 5 degrees difference compared with ideal CobbL4-S1. Finally, the CobbL4-S1 was measured by the PACS system after operation and the consistency was compared between Scoliometer software and PACS system to evaluate the accuracy of this software. In addition, value of this method in obtaining optimal LL was validated by comparing the difference between ideal CobbL4-S1 and preoperative one with that between ideal CobbL4-S1 and postoperative one. The CobbL4-S1 was (36.17 ± 1.53)degrees for ideal one, (22.57 ± 5.50)degrees for preoperative one, (32.25 ± 1.46)degrees for intraoperative one measured by Scoliometer software, and (34.43 ± 1.72)degrees for postoperative one, respectively. The observed intraclass correlation coefficient (ICC) was excellent [ICC = 0.96, 95% confidence interval (0.93, 0.97)] and the mean absolute difference (MAD) was low (MAD = 1.23) between Scoliometer software and PACS system. The deviation between ideal CobbL4-S1 and postoperative CobbL4-S1 was (2.31 ± 0.23)degrees, which was significantly lower than the deviation between ideal CobbL4-S1 and preoperative CobbL4-S1 (13.60 ± 1.85)degrees (t = 6.065, P = 0.001). Scoliometer software can help surgeon obtain

[Food value of the spiruline algae to man].

PubMed

Sautier, C; Tremolieres, J

1975-01-01

The acceptability of various culinary products based on the algae spirulina was tested by questionaire: formulas rich in proteins, soups, omelets, desserts. Spirulina are little appreciated in France due to offensive color, smell and taste. Tomato and chocolate are the most acceptable flavors. Lyophilisation is preferable to atomisation, and discoloration using alcohol is preferable to the acetone method. The hydrolysate obtained, having neither the smell nor the taste of algae, is excellent. Nitrogen, sodium and potassium balances were recorded in 5 undernourished subjects fed via a gastric tube. The spirulina provided respectively 15 p. 100 (1 subject), 30 p. 100 (2 subjects), and 50 p. 100 (2 subjects) of the protein ration. There were no intestinal problems. The spirulina did not modify the investigated balances. However, faecal nitrogen increased to 2.08 g (compared to control period values, 1.33 g and 1.51 g). The various coefficients: digestibility, nitrogen retention and protein utilization did not vary. In man as in animals, nitrogen retention is satisfactory, but digestibility is diminished. Uric acid did not vary in the urine, but serum values increased slightly. Ingestion of spirulina in small doses even over a long period should be tolerable in the normal subject.

Adaptive Selective Harmonic Minimization Based on ANNs for Cascade Multilevel Inverters With Varying DC Sources

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

Filho, Faete; Maia, Helder Z; Mateus, Tiago Henrique D

2013-01-01

A new approach for modulation of an 11-level cascade multilevel inverter using selective harmonic elimination is presented in this paper. The dc sources feeding the multilevel inverter are considered to be varying in time, and the switching angles are adapted to the dc source variation. This method uses genetic algorithms to obtain switching angles offline for different dc source values. Then, artificial neural networks are used to determine the switching angles that correspond to the real-time values of the dc sources for each phase. This implies that each one of the dc sources of this topology can have different valuesmore » at any time, but the output fundamental voltage will stay constant and the harmonic content will still meet the specifications. The modulating switching angles are updated at each cycle of the output fundamental voltage. This paper gives details on the method in addition to simulation and experimental results.« less

Service quality and perceived customer value in community pharmacies.

PubMed

Guhl, Dennis; Blankart, Katharina E; Stargardt, Tom

2018-01-01

A patient's perception of the service provided by a health care provider is essential for the successful delivery of health care. This study examines the value created by community pharmacies-defined as perceived customer value-in the prescription drug market through varying elements of service quality. We develop a path model that describes the relationship between service elements and perceived customer value. We then analyze the effect of perceived customer value on customer satisfaction and loyalty. We use data obtained from 289 standardized interviews on respondents' prescription fill in the last six months in Germany. The service elements personal interaction (path coefficient: 0.31), physical aspect (0.12), store policy (0.24), and availability (0.1) have a positive significant effect on perceived customer value. Consultation and reliability have no significant influence. We further find a strong positive interdependency between perceived customer value, customer satisfaction (0.75), and customer loyalty (0.71). Thus, pharmacies may enhance customer satisfaction and loyalty if they consider the customer perspective and focus on the relevant service elements. To enhance benefit, personal interaction appears to be most important to address appropriately.

Design of crusher liner based on time - varying uncertainty theory

NASA Astrophysics Data System (ADS)

Tang, J. C.; Shi, B. Q.; Yu, H. J.; Wang, R. J.; Zhang, W. Y.

2017-09-01

This article puts forward the time-dependent design method considering the load fluctuation factors for the liner based on the time-varying uncertainty theory. In this method, the time-varying uncertainty design model of liner is constructed by introducing the parameters that affect the wear rate, the volatility and the drift rate. Based on the design example, the timevarying design outline of the moving cone liner is obtained. Based on the theory of minimum wear, the gap curve of wear resistant cavity is designed, and the optimized cavity is obtained by the combination of the thickness of the cone and the cavity gap. Taking the PYGB1821 multi cylinder hydraulic cone crusher as an example, it is proved that the service life of the new liner is improved by more than 14.3%.

Valuing inter-sectoral costs and benefits of interventions in the healthcare sector: methods for obtaining unit prices.

PubMed

Drost, Ruben M W A; Paulus, Aggie T G; Ruwaard, Dirk; Evers, Silvia M A A

2017-02-01

There is a lack of knowledge about methods for valuing health intervention-related costs and monetary benefits in the education and criminal justice sectors, also known as 'inter-sectoral costs and benefits' (ICBs). The objective of this study was to develop methods for obtaining unit prices for the valuation of ICBs. By conducting an exploratory literature study and expert interviews, several generic methods were developed. The methods' feasibility was assessed through application in the Netherlands. Results were validated in an expert meeting, which was attended by policy makers, public health experts, health economists and HTA-experts, and discussed at several international conferences and symposia. The study resulted in four methods, including the opportunity cost method (A) and valuation using available unit prices (B), self-constructed unit prices (C) or hourly labor costs (D). The methods developed can be used internationally and are valuable for the broad international field of HTA.

Stereoscopic depth perception varies with hues

NASA Astrophysics Data System (ADS)

Chen, Zaiqing; Shi, Junsheng; Tai, Yonghang; Yun, Lijun

2012-09-01

The contribution of color information to stereopsis is controversial, and whether the stereoscopic depth perception varies with chromaticity is ambiguous. This study examined the changes in depth perception caused by hue variations. Based on the fact that a greater disparity range indicates more efficient stereoscopic perception, the effect of hue variations on depth perception was evaluated through the disparity range with random-dot stereogram stimuli. The disparity range was obtained by constant-stimulus method for eight chromaticity points sampled from the CIE 1931 chromaticity diagram. Eight sample points include four main color hues: red, yellow, green, and blue at two levels of chroma. The results show that the disparity range for the yellow hue is greater than the red hue, the latter being greater than the blue hue and the disparity range for green hue is smallest. We conclude that the perceived depth is not the same for different hues for a given size of disparity. We suggest that the stereoscopic depth perception can vary with chromaticity.

Optical waveguide device with an adiabatically-varying width

DOEpatents

Watts,; Michael R. , Nielson; Gregory, N [Albuquerque, NM

2011-05-10

Optical waveguide devices are disclosed which utilize an optical waveguide having a waveguide bend therein with a width that varies adiabatically between a minimum value and a maximum value of the width. One or more connecting members can be attached to the waveguide bend near the maximum value of the width thereof to support the waveguide bend or to supply electrical power to an impurity-doped region located within the waveguide bend near the maximum value of the width. The impurity-doped region can form an electrical heater or a semiconductor junction which can be activated with a voltage to provide a variable optical path length in the optical waveguide. The optical waveguide devices can be used to form a tunable interferometer (e.g. a Mach-Zehnder interferometer) which can be used for optical modulation or switching. The optical waveguide devices can also be used to form an optical delay line.

Relative stability of DNA as a generic criterion for promoter prediction: whole genome annotation of microbial genomes with varying nucleotide base composition.

PubMed

Rangannan, Vetriselvi; Bansal, Manju

2009-12-01

The rapid increase in genome sequence information has necessitated the annotation of their functional elements, particularly those occurring in the non-coding regions, in the genomic context. Promoter region is the key regulatory region, which enables the gene to be transcribed or repressed, but it is difficult to determine experimentally. Hence an in silico identification of promoters is crucial in order to guide experimental work and to pin point the key region that controls the transcription initiation of a gene. In this analysis, we demonstrate that while the promoter regions are in general less stable than the flanking regions, their average free energy varies depending on the GC composition of the flanking genomic sequence. We have therefore obtained a set of free energy threshold values, for genomic DNA with varying GC content and used them as generic criteria for predicting promoter regions in several microbial genomes, using an in-house developed tool PromPredict. On applying it to predict promoter regions corresponding to the 1144 and 612 experimentally validated TSSs in E. coli (50.8% GC) and B. subtilis (43.5% GC) sensitivity of 99% and 95% and precision values of 58% and 60%, respectively, were achieved. For the limited data set of 81 TSSs available for M. tuberculosis (65.6% GC) a sensitivity of 100% and precision of 49% was obtained.

A discrete choice experiment to obtain a tariff for valuing informal care situations measured with the CarerQol instrument.

PubMed

Hoefman, Renske J; van Exel, Job; Rose, John M; van de Wetering, E J; Brouwer, Werner B F

2014-01-01

Economic evaluations adopting a societal perspective need to include informal care whenever relevant. However, in practice, informal care is often neglected, because there are few validated instruments to measure and value informal care for inclusion in economic evaluations. The CarerQol, which is such an instrument, measures the impact of informal care on 7 important burden dimensions (CarerQol-7D) and values this in terms of general quality of life (CarerQol-VAS). The objective of the study was to calculate utility scores based on relative utility weights for the CarerQol-7D. These tariffs will facilitate inclusion of informal care in economic evaluations. The CarerQol-7D tariff was derived with a discrete choice experiment conducted as an Internet survey among the general adult population in the Netherlands (N = 992). The choice set contained 2 unlabeled alternatives described in terms of the 7 CarerQol-7D dimensions (level range: "no,"some," and "a lot"). An efficient experimental design with priors obtained from a pilot study (N = 104) was used. Data were analyzed with a panel mixed multinomial parameter model including main and interaction effects of the attributes. The utility attached to informal care situations was significantly higher when this situation was more attractive in terms of fewer problems and more fulfillment or support. The interaction term between the CarerQol-7D dimensions physical health and mental health problems also significantly explained this utility. The tariff was constructed by adding up the relative utility weights per category of all CarerQol-7D dimensions and the interaction term. We obtained a tariff providing standard utility scores for caring situations described with the CarerQol-7D. This facilitates the inclusion of informal care in economic evaluations.

Performance Optimizing Adaptive Control with Time-Varying Reference Model Modification

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.; Hashemi, Kelley E.

2017-01-01

This paper presents a new adaptive control approach that involves a performance optimization objective. The control synthesis involves the design of a performance optimizing adaptive controller from a subset of control inputs. The resulting effect of the performance optimizing adaptive controller is to modify the initial reference model into a time-varying reference model which satisfies the performance optimization requirement obtained from an optimal control problem. The time-varying reference model modification is accomplished by the real-time solutions of the time-varying Riccati and Sylvester equations coupled with the least-squares parameter estimation of the sensitivities of the performance metric. The effectiveness of the proposed method is demonstrated by an application of maneuver load alleviation control for a flexible aircraft.

Obtaining the Iodine Value of Various Oils via Bromination with Pyridinium Tribromide

ERIC Educational Resources Information Center

Simurdiak, Michael; Olukoga, Olushola; Hedberg, Kirk

2016-01-01

A laboratory exercise was devised that allows students to rapidly and fairly accurately determine the iodine value of oleic acid. This method utilizes the addition of elemental bromine to the unsaturated bonds in oleic acid, due to bromine's relatively fast reaction rate compared to that of the traditional Wijs solution method. This method also…

Value Orientations of Future Teachers-Researchers

ERIC Educational Resources Information Center

Botalova, Olga B.; Osipova, Seraphima V.; Asenova, Nazymgul S.; Kenenbaeva, Marzhan A.; Kuderina, Aizhan Y.; Zholtaeva, Gulnar; Boribekova, Farzana; Zhanatbekova, Nazym; Vedilina, Elena A.; Azanbekova, Gulnaz

2016-01-01

Values are keystones of society; they can vary depending on the professional activity. Teacher's values play an important role, since they directly affect the formation of knowledge of students. The paper presents the characteristics of one of the structural components of future teachers' active scientific position--pedagogic values such as…

Administrative database code accuracy did not vary notably with changes in disease prevalence.

PubMed

van Walraven, Carl; English, Shane; Austin, Peter C

2016-11-01

Previous mathematical analyses of diagnostic tests based on the categorization of a continuous measure have found that test sensitivity and specificity varies significantly by disease prevalence. This study determined if the accuracy of diagnostic codes varied by disease prevalence. We used data from two previous studies in which the true status of renal disease and primary subarachnoid hemorrhage, respectively, had been determined. In multiple stratified random samples from the two previous studies having varying disease prevalence, we measured the accuracy of diagnostic codes for each disease using sensitivity, specificity, and positive and negative predictive value. Diagnostic code sensitivity and specificity did not change notably within clinically sensible disease prevalence. In contrast, positive and negative predictive values changed significantly with disease prevalence. Disease prevalence had no important influence on the sensitivity and specificity of diagnostic codes in administrative databases. Copyright © 2016 Elsevier Inc. All rights reserved.

Does the Newtonian Gravity "Constant" G Vary?

NASA Astrophysics Data System (ADS)

Noerdlinger, Peter D.

2015-08-01

A series of measurements of Newton's gravity constant, G, dating back as far as 1893, yielded widely varying values, the variation greatly exceeding the stated error estimates (Gillies, 1997; Quinn, 2000, Mohr et al 2008). The value of G is usually said to be unrelated to other physics, but we point out that the 8B Solar Neutrino Rate ought to be very sensitive. Improved pulsar timing could also help settle the issue as to whether G really varies. We claim that the variation in measured values over time (1893-2014 C.E.) is a more serious problem than the failure of the error bars to overlap; it appears that challenging or adjusting the error bars hardly masks the underlying disagreement in central values. We have assessed whether variations in the gravitational potential due to (for example) local dark matter (DM) could explain the variations. We find that the required potential fluctuations could transiently accelerate the Solar System and nearby stars to speeds in excess of the Galactic escape speed. Previous theories for the variation in G generally deal with supposed secular variation on a cosmological timescale, or very rapid oscillations whose envelope changes on that scale (Steinhardt and Will 1995). Therefore, these analyses fail to support variations on the timescale of years or spatial scales of order parsecs, which would be required by the data for G. We note that true variations in G would be associated with variations in clock rates (Derevianko and Pospelov 2014; Loeb and Maoz 2015), which could mask changes in orbital dynamics. Geringer-Sameth et al (2014) studied γ-ray emission from the nearby Reticulum dwarf galaxy, which is expected to be free of "ordinary" (stellar, black hole) γ-ray sources and found evidence for DM decay. Bernabei et al (2003) also found evidence for DM penetrating deep underground at Gran Sasso. If, indeed, variations in G can be tied to variations in gravitational potential, we have a new tool to assess the DM density.

Are preference and resistance to change convergent expressions of stimulus value?

PubMed

Podlesnik, Christopher A; Jimenez-Gomez, Corina; Shahan, Timothy A

2013-07-01

Behavioral momentum theory asserts that preference and relative resistance to disruption depend on reinforcement rates and provide converging expressions of the conditioned value of discriminative stimuli. However, preference and resistance to disruption diverge when assessing preference during brief extinction probes. We expanded upon this opposing relation by arranging target stimuli signaling equal variable-interval schedules across components of a multiple schedule. We paired one target stimulus with a richer reinforced alternative and the other with a leaner alternative. Furthermore, we varied reinforcement rates for the paired alternatives to assess the effects of manipulating relative conditioned value on preference and resistance to disruption by presession feeding, intercomponent food, and extinction. We replicated the opposing relation between preference and resistance to disruption but varying reinforcement rates for the paired alternatives did not systematically affect preference or resistance to disruption beyond levels observed in our initial condition. Importantly, we found that only preference between the target stimuli was related to relative baseline response rates in the presence of those stimuli. These findings suggest that preference during extinction probes might reveal more about baseline response rates between concurrently available alternatives than relative conditioned value. Resistance to disruption, conversely, appears to better reflect conditioned value because it is less confounded with baseline response rates and is a function of all sources of reinforcement obtained in the presence of a stimulus context. © Society for the Experimental Analysis of Behavior.

Modeling spatially-varying landscape change points in species occurrence thresholds

USGS Publications Warehouse

Wagner, Tyler; Midway, Stephen R.

2014-01-01

Predicting species distributions at scales of regions to continents is often necessary, as large-scale phenomena influence the distributions of spatially structured populations. Land use and land cover are important large-scale drivers of species distributions, and landscapes are known to create species occurrence thresholds, where small changes in a landscape characteristic results in abrupt changes in occurrence. The value of the landscape characteristic at which this change occurs is referred to as a change point. We present a hierarchical Bayesian threshold model (HBTM) that allows for estimating spatially varying parameters, including change points. Our model also allows for modeling estimated parameters in an effort to understand large-scale drivers of variability in land use and land cover on species occurrence thresholds. We use range-wide detection/nondetection data for the eastern brook trout (Salvelinus fontinalis), a stream-dwelling salmonid, to illustrate our HBTM for estimating and modeling spatially varying threshold parameters in species occurrence. We parameterized the model for investigating thresholds in landscape predictor variables that are measured as proportions, and which are therefore restricted to values between 0 and 1. Our HBTM estimated spatially varying thresholds in brook trout occurrence for both the proportion agricultural and urban land uses. There was relatively little spatial variation in change point estimates, although there was spatial variability in the overall shape of the threshold response and associated uncertainty. In addition, regional mean stream water temperature was correlated to the change point parameters for the proportion of urban land use, with the change point value increasing with increasing mean stream water temperature. We present a framework for quantify macrosystem variability in spatially varying threshold model parameters in relation to important large-scale drivers such as land use and land cover

Contrast and autoshaping in multiple schedules varying reinforcer rate and duration.

PubMed

Hamilton, B E; Silberberg, A

1978-07-01

Thirteen master pigeons were exposed to multiple schedules in which reinforcement frequency (Experiment I) or duration (Experiment II) was varied. In Phases 1 and 3 of Experiment I, the values of the first and second components' random-interval schedules were 33 and 99 seconds, respectively. In Phase 2, these values were 99 seconds for both components. In Experiment II, a random-interval 33-second schedule was associated with each component. During Phases 1 and 3, the first and second components had hopper durations of 7.5 and 2.5 seconds respectively. During Phase 2, both components' hopper durations were 2.5 seconds. In each experiment, positive contrast obtained for about half the master subjects. The rest showed a rate increase in both components (positive induction). Each master subject's key colors and reinforcers were synchronously presented on a response-independent basis to a yoked control. Richer component key-pecking occurred during each experiment's Phases 1 and 3 among half these subjects. However, none responded during the contrast condition (unchanged component of each experiment's Phase 2). From this it is inferred that autoshaping did not contribute to the contrast and induction findings among master birds. Little evidence of local contrast (highest rate at beginning of richer component) was found in any subject. These data show that (a) contrast can occur independently from autoshaping, (b) contrast assays during equal-valued components may produce induction, (c) local contrast in multiple schedules often does not occur, and (d) differential hopper durations can produce autoshaping and contrast.

Contrast and autoshaping in multiple schedules varying reinforcer rate and duration

PubMed Central

Hamilton, Bruce E.; Silberberg, Alan

1978-01-01

Thirteen master pigeons were exposed to multiple schedules in which reinforcement frequency (Experiment I) or duration (Experiment II) was varied. In Phases 1 and 3 of Experiment I, the values of the first and second components' random-interval schedules were 33 and 99 seconds, respectively. In Phase 2, these values were 99 seconds for both components. In Experiment II, a random-interval 33-second schedule was associated with each component. During Phases 1 and 3, the first and second components had hopper durations of 7.5 and 2.5 seconds respectively. During Phase 2, both components' hopper durations were 2.5 seconds. In each experiment, positive contrast obtained for about half the master subjects. The rest showed a rate increase in both components (positive induction). Each master subject's key colors and reinforcers were synchronously presented on a response-independent basis to a yoked control. Richer component key-pecking occurred during each experiment's Phases 1 and 3 among half these subjects. However, none responded during the contrast condition (unchanged component of each experiment's Phase 2). From this it is inferred that autoshaping did not contribute to the contrast and induction findings among master birds. Little evidence of local contrast (highest rate at beginning of richer component) was found in any subject. These data show that (a) contrast can occur independently from autoshaping, (b) contrast assays during equal-valued components may produce induction, (c) local contrast in multiple schedules often does not occur, and (d) differential hopper durations can produce autoshaping and contrast. PMID:16812081

Robust linear parameter-varying control of blood pressure using vasoactive drugs

NASA Astrophysics Data System (ADS)

Luspay, Tamas; Grigoriadis, Karolos

2015-10-01

Resuscitation of emergency care patients requires fast restoration of blood pressure to a target value to achieve hemodynamic stability and vital organ perfusion. A robust control design methodology is presented in this paper for regulating the blood pressure of hypotensive patients by means of the closed-loop administration of vasoactive drugs. To this end, a dynamic first-order delay model is utilised to describe the vasoactive drug response with varying parameters that represent intra-patient and inter-patient variability. The proposed framework consists of two components: first, an online model parameter estimation is carried out using a multiple-model extended Kalman-filter. Second, the estimated model parameters are used for continuously scheduling a robust linear parameter-varying (LPV) controller. The closed-loop behaviour is characterised by parameter-varying dynamic weights designed to regulate the mean arterial pressure to a target value. Experimental data of blood pressure response of anesthetised pigs to phenylephrine injection are used for validating the LPV blood pressure models. Simulation studies are provided to validate the online model estimation and the LPV blood pressure control using phenylephrine drug injection models representing patients showing sensitive, nominal and insensitive response to the drug.

Subjective value of risky foods for individual domestic chicks: a hierarchical Bayesian model.

PubMed

Kawamori, Ai; Matsushima, Toshiya

2010-05-01

For animals to decide which prey to attack, the gain and delay of the food item must be integrated in a value function. However, the subjective value is not obtained by expected profitability when it is accompanied by risk. To estimate the subjective value, we examined choices in a cross-shaped maze with two colored feeders in domestic chicks. When tested by a reversal in food amount or delay, chicks changed choices similarly in both conditions (experiment 1). We therefore examined risk sensitivity for amount and delay (experiment 2) by supplying one feeder with food of fixed profitability and the alternative feeder with high- or low-profitability food at equal probability. Profitability varied in amount (groups 1 and 2 at high and low variance) or in delay (group 3). To find the equilibrium, the amount (groups 1 and 2) or delay (group 3) of the food in the fixed feeder was adjusted in a total of 18 blocks. The Markov chain Monte Carlo method was applied to a hierarchical Bayesian model to estimate the subjective value. Chicks undervalued the variable feeder in group 1 and were indifferent in group 2 but overvalued the variable feeder in group 3 at a population level. Re-examination without the titration procedure (experiment 3) suggested that the subjective value was not absolute for each option. When the delay was varied, the variable option was often given a paradoxically high value depending on fixed alternative. Therefore, the basic assumption of the uniquely determined value function might be questioned.

On radiating baroclinic instability of zonally varying flow

NASA Technical Reports Server (NTRS)

Finley, Catherine A.; Nathan, Terrence R.

1993-01-01

A quasi-geostrophic, two-layer, beta-plane model is used to study the baroclinic instability characteristics of a zonally inhomogeneous flow. It is assumed that the disturbance varied slowly in the cross-stream direction, and the stability problem was formulated as a 1D initial value problem. Emphasis is placed on determining how the vertically averaged wind, local maximum in vertical wind shear, and length of the locally supercritical region combine to yield local instabilities. Analysis of the local disturbance energetics reveals that, for slowly varying basic states, the baroclinic energy conversion predominates within the locally unstable region. Using calculations of the basic state tendencies, it is shown that the net effect of the local instabilities is to redistribute energy from the baroclinic to the barotropic component of the basic state flow.

Comparison of the T2-star Values of Placentas Obtained from Pre-eclamptic Patients with Those of a Control Group: an Ex-vivo Magnetic Resonance Imaging Study.

PubMed

Yurttutan, Nursel; Bakacak, Murat; Kızıldağ, Betül

2017-09-29

Endotel dysfunction, vasoconstriction, and oxidative stress are described in the pathophysiology of pre-eclampsia, but its aetiology has not been revealed clearly. To examine whether there is a difference between the placentas of pre-eclamptic pregnant women and those of a control group in terms of their T2 star values. Case-control study. Twenty patients diagnosed with pre-eclampsia and 22 healthy controls were included in this study. The placentas obtained after births performed via Caesarean section were taken into the magnetic resonance imaging area in plastic bags within the first postnatal hour, and imaging was performed via modified DIXON-Quant sequence. Average values were obtained by performing T2 star measurements from four localisations on the placentas. T2 star values measured in the placentas of the control group were found to be significantly lower than those in the pre-eclampsia group (p<0.01). While the mean T2 star value in the pre-eclamptic group was found to be 37.48 ms (standard deviation ± 11.3), this value was 28.74 (standard deviation ± 8.08) in the control group. The cut-off value for the T2 star value, maximising the accuracy of diagnosis, was 28.59 ms (area under curve: 0.741; 95% confidence interval: 0.592-0.890); sensitivity and specificity were 70% and 63.6%, respectively. This study, the T2 star value, which is an indicator of iron amount, was found to be significantly lower in the control group than in the pre-eclampsia group. This may be related to the reduction in blood flow to the placenta due to endothelial dysfunction and vasoconstriction, which are important in pre-eclampsia pathophysiology.

Correlation of Lactic Acid and Base Deficit Values Obtained From Arterial and Peripheral Venous Samples in a Pediatric Population During Intraoperative Care.

PubMed

Bordes, Brianne M; Walia, Hina; Sebastian, Roby; Martin, David; Tumin, Dmitry; Tobias, Joseph D

2017-12-01

Lactic acid and base deficit (BD) values are frequently monitored in the intensive care unit and operating room setting to evaluate oxygenation, ventilation, cardiac output, and peripheral perfusion. Although generally obtained from an arterial cannula, such access may not always be available. The current study prospectively investigates the correlation of arterial and peripheral venous values of BD and lactic acid. The study cohort included 48 patients. Arterial BD values ranged from -8 to 4 mEq/L and peripheral venous BD values ranged from -8 to 4 mEq/L. Arterial lactic acid values ranged from 0.36 to 2.45 μmol/L and peripheral venous lactic acid values ranged from 0.38 to 4 μmol/L. The arterial BD (-0.4 ± 2.2 mEq/L) was not significantly different from the peripheral venous BD (-0.6 ± 2.2 mEq/L). The arterial lactic acid (1.0 ± 0.5 μmol/L) was not significantly different from the peripheral venous lactic acid (1.1 ± 0.6 μmol/L). Pearson correlation coefficients demonstrated a very high correlation between arterial and peripheral venous BD ( r = .88, P < .001) and between arterial and peripheral venous lactic acid ( r = .67, P < .001). Bland-Altman plots of both pairs of measures showed that the majority of observations fell within the 95% limits of agreement. Least-squares regression indicated that a 1-unit increase in arterial BD corresponded to a 0.9-unit increase in peripheral venous BD (95% confidence interval [CI]: 0.7-1.0; P < .001) and a 1-unit increase in arterial lactic acid corresponded to a 0.9-unit increase in peripheral venous lactic acid (95% CI: 0.6-1.2; P < .001). These data demonstrate that there is a clinically useful correlation between arterial and peripheral venous lactic acid and BD values.

Rational-q Triggered Transport Changes With Varying Toroidal Rotation in DIII-D

NASA Astrophysics Data System (ADS)

Austin, M. E.; Burrell, K. H.; Waltz, R. E.; van Zeeland, M. A.; McKee, G. R.; Shafer, M. W.; Rhodes, T. L.

2007-11-01

Comparison of rational-q triggered ITBs in discharges with varying toroidal torque injection was carried out. Experiments were conducted in negative central shear discharges with different mixes of co/counter neutral beam injection (NBI) that altered the equilibrium ExB shear in conditions where transient improvements in transport occur near integer qmin values. The transport changes were seen in high and low rotation cases; however, the latter discharges did not transition to improved core confinement. Observations support the model that sufficient background ExB shear is required for barrier formation and zonal flow effects at integer qmin act as trigger in this case. The lack of TAE modes in the balanced injection cases indicates they are not linked to the transient confinement improvement. Fluctuation data obtained in co and balanced NBI show similar reductions in turbulence near integer qmin as well as poloidal velocity excursions that may be further evidence of zonal flow.

Using the Climbing Drum Peel (CDP) Test to Obtain a G(sub IC) value for Core/Facesheet Bonds

NASA Technical Reports Server (NTRS)

Nettles, A. T.; Gregory, Elizabeth D.; Jackson, Justin R.

2006-01-01

A method of measuring the Mode I fracture toughness of core/facesheet bonds in sandwich Structures is desired, particularly with the widespread use of models that need this data as input. This study examined if a critical strain energy release rate, G(sub IC), can be obtained from the climbing drum peel (CDP) test. The CDP test is relatively simple to perform and does not rely on measuring small crack lengths such as required by the double cantilever beam (DCB) test. Simple energy methods were used to calculate G(sub IC) from CDP test data on composite facesheets bonded to a honeycomb core. Facesheet thicknesses from 2 to 5 plies were tested to examine the upper and lower bounds on facesheet thickness requirements. Results from the study suggest that the CDP test, with certain provisions, can be used to find the GIG value of a core/facesheet bond.

Time-varying higher order spectra

NASA Astrophysics Data System (ADS)

Boashash, Boualem; O'Shea, Peter

1991-12-01

A general solution for the problem of time-frequency signal representation of nonlinear FM signals is provided, based on a generalization of the Wigner-Ville distribution. The Wigner- Ville distribution (WVD) is a second order time-frequency representation. That is, it is able to give ideal energy concentration for quadratic phase signals and its ensemble average is a second order time-varying spectrum. The same holds for Cohen's class of time-frequency distributions, which are smoothed versions of the WVD. The WVD may be extended so as to achieve ideal energy concentration for higher order phase laws, and such that the expectation is a time-varying higher order spectrum. The usefulness of these generalized Wigner-Ville distributions (GWVD) is twofold. Firstly, because they achieve ideal energy concentration for polynomial phase signals, they may be used for optimal instantaneous frequency estimation. Second, they are useful for discriminating between nonstationary processes of differing higher order moments. In the same way that the WVD is generalized, we generalize Cohen's class of TFDs by defining a class of generalized time-frequency distributions (GTFDs) obtained by a two dimensional smoothing of the GWVD. Another results derived from this approach is a method based on higher order spectra which allows the separation of cross-terms and auto- terms in the WVD.

Light sensitometry of mammography films at varying development temperatures and times

PubMed Central

Sharma, Reena; Sharma, Sunil Dutt; Mayya, Y. S.

2012-01-01

Kodak MinR-2000 mammography film is widely used for mammography imaging. The sensitometric indices like base plus fog level (B + F), maximum optical density (ODmax), average gradient (AG) and speed of this film at varying development temperatures and times were evaluated using a light sensitometer. Totally 33 film strips were cut from a single Kodak MinR-2000 mammography film box and exposed in a light sensitometer operated in the green light spectrum to produce a 21-step sensitometric strip. These exposed film strips were processed at temperatures in the range of 32°C–37°C in the step of 1°C and at processing times in the range of 1–6 minutes in the step of 1 minute. The results of the present study show that the measured base plus fog level of the mammography film was not affected much, whereas significant changes were seen in the ODmax, AG and speed with varying development temperatures and times. The ODmax values of the film were found in the range of 3.67–3.76, AG values were in the range of 2.48–3.4 and speed values were in the range of 0.015–0.0236 when the processing temperature was varied from 32°C to 37°C. With processing time variation from 1 to 6 minutes, the observed changes in ODmax values were in the range of 3.54-3.71, changes in AG were in the range of 2.66–3.27 and changes in speed were in the range of 0.011–0.025. Based on these observations, recommendations for optimum processing parameters to be used for this film are made. PMID:22363111

Impedance Eduction in Sound Fields With Peripherally Varying Liners and Flow

NASA Technical Reports Server (NTRS)

Watson, W. R.; Jones, M. G.

2015-01-01

A two-dimensional impedance eduction theory is extended to three-dimensional sound fields and peripherally varying duct liners. The approach is to first measure the acoustic pressure field at a series of flush-mounted wall microphones located around the periphery of the flow duct. The numerical solution for the acoustic pressure field at these microphones is also obtained by solving the three-dimensional convected Helmholtz equation using the finite element method. A quadratic objective function based on the difference between the measured and finite element solution is constructed and the unknown impedance function is obtained by minimizing this objective function. Impedance spectra educed for two uniform-structure liners (a wire-mesh and a conventional liner) and a hard-soft-hard peripherally varying liner (for which the soft segment is that of the conventional liner) are presented. Results are presented at three mean flow Mach numbers and fourteen sound source frequencies. The impedance spectra of the uniform-structure liners are also computed using a two-dimensional impedance eduction theory. The primary conclusions of the study are: 1) when measured data is used with the uniform-structure liners, the three-dimensional theory reproduces the same impedance spectra as the two-dimensional theory except for frequencies corresponding to very low or very high liner attenuation; and 2) good agreement between the educed impedance spectra of the uniform structure conventional liner and the soft segment of the peripherally varying liner is obtained.

Optimal critic learning for robot control in time-varying environments.

PubMed

Wang, Chen; Li, Yanan; Ge, Shuzhi Sam; Lee, Tong Heng

2015-10-01

In this paper, optimal critic learning is developed for robot control in a time-varying environment. The unknown environment is described as a linear system with time-varying parameters, and impedance control is employed for the interaction control. Desired impedance parameters are obtained in the sense of an optimal realization of the composite of trajectory tracking and force regulation. Q -function-based critic learning is developed to determine the optimal impedance parameters without the knowledge of the system dynamics. The simulation results are presented and compared with existing methods, and the efficacy of the proposed method is verified.

47 CFR 54.615 - Obtaining services.

Code of Federal Regulations, 2010 CFR

2010-10-01

... provided under § 54.621, that the requester cannot obtain toll-free access to an Internet service provider... thing of value; (6) If the service or services are being purchased as part of an aggregated purchase...

[Full blood count reference values in children of 8 to 12 years old residing at 2,760 m above sea level].

PubMed

Armando García-Miranda, L; Contreras, I; Estrada, J A

2014-04-01

To determine reference values for full blood count parameters in a population of children 8 to 12 years old, living at an altitude of 2760 m above sea level. Our sample consisted of 102 individuals on whom a full blood count was performed. The parameters included: total number of red blood cells, platelets, white cells, and a differential count (millions/μl and %) of neutrophils, lymphocytes, monocytes, eosinophils and basophils. Additionally, we obtained values for hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, concentration of corpuscular hemoglobin and red blood cell distribution width. The results were statistically analyzed with a non-parametric test, to divide the sample in quartiles and obtain the lower and upper limits for our intervals. Moreover, the values for the intervals obtained from this analysis were compared to intervals obtained estimating+- 2 standard deviations above and below from our mean values. Our results showed significant differences compared to normal interval values reported for the adult Mexican population in most of the parameters studied. The full blood count is an important laboratory test used routinely for the initial assessment of a patient. Values of full blood counts in healthy individuals vary according to gender, age and geographic location; therefore, each population should have its own reference values. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

WE-G-18C-02: Estimation of Optimal B-Value Set for Obtaining Apparent Diffusion Coefficient Free From Perfusion in Non-Small Cell Lung Cancer

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

Karki, K; Hugo, G; Ford, J

2014-06-15

Purpose: Diffusion-weighted MRI (DW-MRI) is increasingly being investigated for radiotherapy planning and response assessment. Selection of a limited number of b-values in DW-MRI is important to keep geometrical variations low and imaging time short. We investigated various b-value sets to determine an optimal set for obtaining monoexponential apparent diffusion coefficient (ADC) close to perfusion-insensitive intravoxel incoherent motion (IVIM) model ADC (ADC IVIM) in nonsmall cell lung cancer. Methods: Seven patients had 27 DW-MRI scans before and during radiotherapy in a 1.5T scanner. Respiratory triggering was applied to the echo-planar DW-MRI with TR=4500ms approximately, TE=74ms, pixel size=1.98X1.98mm{sub 2}, slice thickness=4–6mm andmore » 7 axial slices. Diffusion gradients were applied to all three axes producing traceweighted images with eight b-values of 0–1000μs/μm{sup 2}. Monoexponential model ADC values using various b-value sets were compared to ADC IVIM using all b-values. To compare the relative noise in ADC maps, intra-scan coefficient of variation (CV) of active tumor volumes was computed. Results: ADC IVIM, perfusion coefficient and perfusion fraction for tumor volumes were in the range of 880-1622 μm{sup 2}/s, 8119-33834 μm{sup 2}/s and 0.104–0.349, respectively. ADC values using sets of 250, 800 and 1000; 250, 650 and 1000; and 250–1000μs/μm{sup 2} only were not significantly different from ADC IVIM(p>0.05, paired t-test). Error in ADC values for 0–1000, 50–1000, 100–1000, 250–1000, 500–1000, and three b-value sets- 250, 500 and 1000; 250, 650 and 1000; and 250, 800 and 1000μs/μm{sup 2} were 15.0, 9.4, 5.6, 1.4, 11.7, 3.7, 2.0 and 0.2% relative to the reference-standard ADC IVIM, respectively. Mean intrascan CV was 20.2, 20.9, 21.9, 24.9, 32.6, 25.8, 25.4 and 24.8%, respectively, whereas that for ADC IVIM was 23.3%. Conclusion: ADC values of two 3 b-value sets (250, 650 and 1000; and 250, 800 and 1000μs/μm{sup 2

Limit case analysis of the "stable indenter velocity" method for obtaining creep stress exponents from constant load indentation creep tests

NASA Astrophysics Data System (ADS)

Campbell, J.; Dean, J.; Clyne, T. W.

2017-02-01

This study concerns a commonly-used procedure for evaluating the steady state creep stress exponent, n, from indentation data. The procedure involves monitoring the indenter displacement history under constant load and making the assumption that, once its velocity has stabilised, the system is in a quasi-steady state, with stage II creep dominating the behaviour. The stress and strain fields under the indenter are represented by "equivalent stress" and "equivalent strain rate" values. The estimate of n is then obtained as the gradient of a plot of the logarithm of the equivalent strain rate against the logarithm of the equivalent stress. Concerns have, however, been expressed about the reliability of this procedure, and indeed it has already been shown to be fundamentally flawed. In the present paper, it is demonstrated, using a very simple analysis, that, for a genuinely stable velocity, the procedure always leads to the same, constant value for n (either 1.0 or 0.5, depending on whether the tip shape is spherical or self-similar). This occurs irrespective of the value of the measured velocity, or indeed of any creep characteristic of the material. It is now clear that previously-measured values of n, obtained using this procedure, have varied in a more or less random fashion, depending on the functional form chosen to represent the displacement-time history and the experimental variables (tip shape and size, penetration depth, etc.), with little or no sensitivity to the true value of n.

Means for ultrasonic testing when material properties vary

DOEpatents

Beller, Laurence S.

1979-01-01

A device is provided for maintaining constant sensitivity in an ultrasonic testing device, despite varying attenuation due to the properties of the material being tested. The device includes a sensor transducer for transmitting and receiving a test signal and a monitor transducer positioned so as to receive ultrasonic energy transmitted through the material to be tested. The received signal of the monitor transducer is utilized in analyzing data obtained from the sensor transducer.

Investigating Constituent Values and School Policy

ERIC Educational Resources Information Center

Allen, Ann; Glassman, Michael; Riegel, Lisa; Dawson, Heather

2013-01-01

Using a sociopolitical perspective to understand the alignment of community values and school policies, we conducted focus groups in three geographically close but economically varied neighborhood in one Midwest urban area. The article presents findings related to constituent values, social capital, and school policies, including charter school…

Varying ultrasound power level to distinguish surgical instruments and tissue.

PubMed

Ren, Hongliang; Anuraj, Banani; Dupont, Pierre E

2018-03-01

We investigate a new framework of surgical instrument detection based on power-varying ultrasound images with simple and efficient pixel-wise intensity processing. Without using complicated feature extraction methods, we identified the instrument with an estimated optimal power level and by comparing pixel values of varying transducer power level images. The proposed framework exploits the physics of ultrasound imaging system by varying the transducer power level to effectively distinguish metallic surgical instruments from tissue. This power-varying image-guidance is motivated from our observations that ultrasound imaging at different power levels exhibit different contrast enhancement capabilities between tissue and instruments in ultrasound-guided robotic beating-heart surgery. Using lower transducer power levels (ranging from 40 to 75% of the rated lowest ultrasound power levels of the two tested ultrasound scanners) can effectively suppress the strong imaging artifacts from metallic instruments and thus, can be utilized together with the images from normal transducer power levels to enhance the separability between instrument and tissue, improving intraoperative instrument tracking accuracy from the acquired noisy ultrasound volumetric images. We performed experiments in phantoms and ex vivo hearts in water tank environments. The proposed multi-level power-varying ultrasound imaging approach can identify robotic instruments of high acoustic impedance from low-signal-to-noise-ratio ultrasound images by power adjustments.

Network Inference via the Time-Varying Graphical Lasso

PubMed Central

Hallac, David; Park, Youngsuk; Boyd, Stephen; Leskovec, Jure

2018-01-01

Many important problems can be modeled as a system of interconnected entities, where each entity is recording time-dependent observations or measurements. In order to spot trends, detect anomalies, and interpret the temporal dynamics of such data, it is essential to understand the relationships between the different entities and how these relationships evolve over time. In this paper, we introduce the time-varying graphical lasso (TVGL), a method of inferring time-varying networks from raw time series data. We cast the problem in terms of estimating a sparse time-varying inverse covariance matrix, which reveals a dynamic network of interdependencies between the entities. Since dynamic network inference is a computationally expensive task, we derive a scalable message-passing algorithm based on the Alternating Direction Method of Multipliers (ADMM) to solve this problem in an efficient way. We also discuss several extensions, including a streaming algorithm to update the model and incorporate new observations in real time. Finally, we evaluate our TVGL algorithm on both real and synthetic datasets, obtaining interpretable results and outperforming state-of-the-art baselines in terms of both accuracy and scalability. PMID:29770256

Intraocular pressure values obtained by ocular response analyzer, dynamic contour tonometry, and goldmann tonometry in keratokonic corneas.

PubMed

Bayer, Atilla; Sahin, Afsun; Hürmeriç, Volkan; Ozge, Gökhan

2010-01-01

To determine the agreement between dynamic contour tonometer (DCT), Goldmann applanation tonometer (GAT), and Ocular Response Analyzer (ORA) in keratoconic corneas and to find out the effect of corneal biomechanics on intraocular pressure (IOP) measurements obtained by these devices. IOP was measured with the ORA, DCT, and GAT in random order in 120 eyes of 61 keratoconus patients. Central corneal thickness (CCT) and keratometry were measured after all IOP determinations had been made. The mean IOP measurement by the ORA and DCT was compared with the measurement by the GAT, using Student t test. Bland-Altman analysis was performed to assess the clinical agreement between these methods. The effect of corneal hysteresis (CH), corneal resistance factor (CRF), and CCT on measured IOP was explored by multiple backward stepwise linear regression analysis. The mean±SD patient age was 30.6±11.2 years. The mean±SD IOP measurement obtained with GAT, ORA Goldmann-correlated IOP (IOPg), ORA corneal-compensated IOP (IOPcc), and DCT was 10.96±2.8, 10.23±3.5, 14.65±2.8, and 15.42±2.7 mm Hg, respectively. The mean±SD CCT was 464.08±58.4 microns. The mean difference between IOPcc and GAT (P<0.0001), IOPcc and DCT (P<0.001), GAT and DCT (P<0.0001), IOPg and GAT (P<0.002), and IOPg and DCT (P<0.0001), was highly statistically significant. In multivariable regression analysis, DCT IOP and GAT IOP measurements were significantly associated with CH and CRF (P<0.0001 for both). DCT seemed to be affected by CH and CRF, and the IOP values tended to be higher when compared with GAT. ORA-measured IOPcc was found to be independent of CCT and suitable in comparison to the DCT in keratoconic eyes.

Full Value Evolving.

ERIC Educational Resources Information Center

Schoel, Jim

2002-01-01

The evolution of Project Adventure's Full Value Contract from its original No Discount format is described. Although wording varies among groups, all versions ask the group to create safe and respectful behavioral norms under which it will operate, to commit to those norms, and to accept a shared responsibility for their maintenance. (TD)

Power-rate synchronization of coupled genetic oscillators with unbounded time-varying delay.

PubMed

Alofi, Abdulaziz; Ren, Fengli; Al-Mazrooei, Abdullah; Elaiw, Ahmed; Cao, Jinde

2015-10-01

In this paper, a new synchronization problem for the collective dynamics among genetic oscillators with unbounded time-varying delay is investigated. The dynamical system under consideration consists of an array of linearly coupled identical genetic oscillators with each oscillators having unbounded time-delays. A new concept called power-rate synchronization, which is different from both the asymptotical synchronization and the exponential synchronization, is put forward to facilitate handling the unbounded time-varying delays. By using a combination of the Lyapunov functional method, matrix inequality techniques and properties of Kronecker product, we derive several sufficient conditions that ensure the coupled genetic oscillators to be power-rate synchronized. The criteria obtained in this paper are in the form of matrix inequalities. Illustrative example is presented to show the effectiveness of the obtained results.

Obtaining orthotropic elasticity tensor using entries zeroing method.

NASA Astrophysics Data System (ADS)

Gierlach, Bartosz; Danek, Tomasz

2017-04-01

A generally anisotropic elasticity tensor obtained from measurements can be represented by a tensor belonging to one of eight material symmetry classes. Knowledge of symmetry class and orientation is helpful for describing physical properties of a medium. For each non-trivial symmetry class except isotropic this problem is nonlinear. A common method of obtaining effective tensor is a choosing its non-trivial symmetry class and minimizing Frobenius norm between measured and effective tensor in the same coordinate system. Global optimization algorithm has to be used to determine the best rotation of a tensor. In this contribution, we propose a new approach to obtain optimal tensor, with the assumption that it is orthotropic (or at least has a similar shape to the orthotropic one). In orthotropic form tensor 24 out of 36 entries are zeros. The idea is to minimize the sum of squared entries which are supposed to be equal to zero through rotation calculated with optimization algorithm - in this case Particle Swarm Optimization (PSO) algorithm. Quaternions were used to parametrize rotations in 3D space to improve computational efficiency. In order to avoid a choice of local minima we apply PSO several times and only if we obtain similar results for the third time we consider it as a correct value and finish computations. To analyze obtained results Monte-Carlo method was used. After thousands of single runs of PSO optimization, we obtained values of quaternion parts and plot them. Points concentrate in several points of the graph following the regular pattern. It suggests the existence of more complex symmetry in the analyzed tensor. Then thousands of realizations of generally anisotropic tensor were generated - each tensor entry was replaced with a random value drawn from normal distribution having a mean equal to measured tensor entry and standard deviation of the measurement. Each of these tensors was subject of PSO based optimization delivering quaternion for optimal

The Advancement Value Chain: An Exploratory Model

ERIC Educational Resources Information Center

Leonard, Edward F., III

2005-01-01

Since the introduction of the value chain concept in 1985, several varying, yet virtually similar, value chains have been developed for the business enterprise. Shifting to higher education, can a value chain be found that links together the various activities of advancement so that an institution's leaders can actually look at the philanthropic…

A Functional Varying-Coefficient Single-Index Model for Functional Response Data

PubMed Central

Li, Jialiang; Huang, Chao; Zhu, Hongtu

2016-01-01

Motivated by the analysis of imaging data, we propose a novel functional varying-coefficient single index model (FVCSIM) to carry out the regression analysis of functional response data on a set of covariates of interest. FVCSIM represents a new extension of varying-coefficient single index models for scalar responses collected from cross-sectional and longitudinal studies. An efficient estimation procedure is developed to iteratively estimate varying coefficient functions, link functions, index parameter vectors, and the covariance function of individual functions. We systematically examine the asymptotic properties of all estimators including the weak convergence of the estimated varying coefficient functions, the asymptotic distribution of the estimated index parameter vectors, and the uniform convergence rate of the estimated covariance function and their spectrum. Simulation studies are carried out to assess the finite-sample performance of the proposed procedure. We apply FVCSIM to investigating the development of white matter diffusivities along the corpus callosum skeleton obtained from Alzheimer’s Disease Neuroimaging Initiative (ADNI) study. PMID:29200540

A Functional Varying-Coefficient Single-Index Model for Functional Response Data.

PubMed

Li, Jialiang; Huang, Chao; Zhu, Hongtu

2017-01-01

Motivated by the analysis of imaging data, we propose a novel functional varying-coefficient single index model (FVCSIM) to carry out the regression analysis of functional response data on a set of covariates of interest. FVCSIM represents a new extension of varying-coefficient single index models for scalar responses collected from cross-sectional and longitudinal studies. An efficient estimation procedure is developed to iteratively estimate varying coefficient functions, link functions, index parameter vectors, and the covariance function of individual functions. We systematically examine the asymptotic properties of all estimators including the weak convergence of the estimated varying coefficient functions, the asymptotic distribution of the estimated index parameter vectors, and the uniform convergence rate of the estimated covariance function and their spectrum. Simulation studies are carried out to assess the finite-sample performance of the proposed procedure. We apply FVCSIM to investigating the development of white matter diffusivities along the corpus callosum skeleton obtained from Alzheimer's Disease Neuroimaging Initiative (ADNI) study.

Standardizing Foot-Type Classification Using Arch Index Values

PubMed Central

Weil, Rich; de Boer, Emily

2012-01-01

ABSTRACT Purpose: The lack of a reliable classification standard for foot type makes drawing conclusions from existing research and clinical decisions difficult, since different foot types may move and respond to treatment differently. The purpose of this study was to determine interrater agreement for foot-type classification based on photo-box-derived arch index values. Method: For this correlational study with two raters, a sample of 11 healthy volunteers with normal to obese body mass indices was recruited from both a community weight-loss programme and a programme in physical therapy. Arch index was calculated using AutoCAD software from footprint photographs obtained via mirrored photo-box. Classification as high-arched, normal, or low-arched foot type was based on arch index values. Reliability of the arch index was determined with intra-class correlations; agreement on foot-type classification was determined using quadratic weighted kappa (κw). Results: Average arch index was 0.215 for one tester and 0.219 for the second tester, with an overall range of 0.017 to 0.370. Both testers classified 6 feet as low-arched, 9 feet as normal, and 7 feet as high-arched. Interrater reliability for the arch index was ICC=0.90; interrater agreement for foot-type classification was κw=0.923. Conclusions: Classification of foot type based on arch index values derived from plantar footprint photographs obtained via mirrored photo-box showed excellent reliability in people with varying BMI. Foot-type classification may help clinicians and researchers subdivide sample populations to better differentiate mobility, gait, or treatment effects among foot types. PMID:23729964

Stability in Cohen Grossberg-type bidirectional associative memory neural networks with time-varying delays

NASA Astrophysics Data System (ADS)

Cao, Jinde; Song, Qiankun

2006-07-01

In this paper, the exponential stability problem is investigated for a class of Cohen-Grossberg-type bidirectional associative memory neural networks with time-varying delays. By using the analysis method, inequality technique and the properties of an M-matrix, several novel sufficient conditions ensuring the existence, uniqueness and global exponential stability of the equilibrium point are derived. Moreover, the exponential convergence rate is estimated. The obtained results are less restrictive than those given in the earlier literature, and the boundedness and differentiability of the activation functions and differentiability of the time-varying delays are removed. Two examples with their simulations are given to show the effectiveness of the obtained results.

Differences in liver stiffness values obtained with new ultrasound elastography machines and Fibroscan: A comparative study.

PubMed

Piscaglia, Fabio; Salvatore, Veronica; Mulazzani, Lorenzo; Cantisani, Vito; Colecchia, Antonio; Di Donato, Roberto; Felicani, Cristina; Ferrarini, Alessia; Gamal, Nesrine; Grasso, Valentina; Marasco, Giovanni; Mazzotta, Elena; Ravaioli, Federico; Ruggieri, Giacomo; Serio, Ilaria; Sitouok Nkamgho, Joules Fabrice; Serra, Carla; Festi, Davide; Schiavone, Cosima; Bolondi, Luigi

2017-07-01

Whether Fibroscan thresholds can be immediately adopted for none, some or all other shear wave elastography techniques has not been tested. The aim of the present study was to test the concordance of the findings obtained from 7 of the most recent ultrasound elastography machines with respect to Fibroscan. Sixteen hepatitis C virus-related patients with fibrosis ≥2 and having reliable results at Fibroscan were investigated in two intercostal spaces using 7 different elastography machines. Coefficients of both precision (an index of data dispersion) and accuracy (an index of bias correction factors expressing different magnitudes of changes in comparison to the reference) were calculated. Median stiffness values differed among the different machines as did coefficients of both precision (range 0.54-0.72) and accuracy (range 0.28-0.87). When the average of the measurements of two intercostal spaces was considered, coefficients of precision significantly increased with all machines (range 0.72-0.90) whereas of accuracy improved more scatteredly and by a smaller degree (range 0.40-0.99). The present results showed only moderate concordance of the majority of elastography machines with the Fibroscan results, preventing the possibility of the immediate universal adoption of Fibroscan thresholds for defining liver fibrosis staging for all new machines. Copyright © 2017 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Uncertainties in obtaining high reliability from stress-strength models

NASA Technical Reports Server (NTRS)

Neal, Donald M.; Matthews, William T.; Vangel, Mark G.

1992-01-01

There has been a recent interest in determining high statistical reliability in risk assessment of aircraft components. The potential consequences are identified of incorrectly assuming a particular statistical distribution for stress or strength data used in obtaining the high reliability values. The computation of the reliability is defined as the probability of the strength being greater than the stress over the range of stress values. This method is often referred to as the stress-strength model. A sensitivity analysis was performed involving a comparison of reliability results in order to evaluate the effects of assuming specific statistical distributions. Both known population distributions, and those that differed slightly from the known, were considered. Results showed substantial differences in reliability estimates even for almost nondetectable differences in the assumed distributions. These differences represent a potential problem in using the stress-strength model for high reliability computations, since in practice it is impossible to ever know the exact (population) distribution. An alternative reliability computation procedure is examined involving determination of a lower bound on the reliability values using extreme value distributions. This procedure reduces the possibility of obtaining nonconservative reliability estimates. Results indicated the method can provide conservative bounds when computing high reliability. An alternative reliability computation procedure is examined involving determination of a lower bound on the reliability values using extreme value distributions. This procedure reduces the possibility of obtaining nonconservative reliability estimates. Results indicated the method can provide conservative bounds when computing high reliability.

A service-oriented approach to assessing the infrastructure value index.

PubMed

Amaral, R; Alegre, H; Matos, J S

Many national and regional administrations are currently facing challenges to ensure long-term sustainability of urban water services, as infrastructures continue to accumulate alarming levels of deferred maintenance and rehabilitation. The infrastructure value index (IVI) has proven to be an effective tool to support long-term planning, in particular by facilitating the ability to communicate and to create awareness. It is given by the ratio between current value of an infrastructure and its replacement cost. Current value is commonly estimated according to an asset-oriented approach, which is based on the concept of useful life of individual components. The standard values assumed for the useful lives can vary significantly, which leads to valuations that are just as different. Furthermore, with water companies increasingly focused on the customer, effective service-centric asset management is essential now more than ever. This paper shows results of on-going research work, which aims to explore a service-oriented approach for assessing the IVI. The paper presents the fundamentals underlying this approach, discusses and compares results obtained from both perspectives and points to challenges that still need to be addressed.

Child-Langmuir flow with periodically varying anode voltage

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

Rokhlenko, A.

Using the Lagrangian technique, we study settled Child-Langmuir flows in a one dimensional planar diodes whose anode voltages periodically vary around given positive values. Our goal is to find analytically if the average currents in these systems can exceed the famous Child-Langmuir limit found for the stationary current a long time ago. The main result of our study is that in a periodic quasi-stationary regime the average current can be larger than the Child-Langmuir maximum even by 50% compared with its adiabatic average value. The cathode current in this case has the form of rectangular pulses which are formed bymore » a very special triangular voltage modulation. This regime, i.e., periodicity, shape of pulses, and their amplitude, needs to be carefully chosen for the best performance.« less

Accuracy Evaluation of the Unified P-Value from Combining Correlated P-Values

PubMed Central

Alves, Gelio; Yu, Yi-Kuo

2014-01-01

Meta-analysis methods that combine -values into a single unified -value are frequently employed to improve confidence in hypothesis testing. An assumption made by most meta-analysis methods is that the -values to be combined are independent, which may not always be true. To investigate the accuracy of the unified -value from combining correlated -values, we have evaluated a family of statistical methods that combine: independent, weighted independent, correlated, and weighted correlated -values. Statistical accuracy evaluation by combining simulated correlated -values showed that correlation among -values can have a significant effect on the accuracy of the combined -value obtained. Among the statistical methods evaluated those that weight -values compute more accurate combined -values than those that do not. Also, statistical methods that utilize the correlation information have the best performance, producing significantly more accurate combined -values. In our study we have demonstrated that statistical methods that combine -values based on the assumption of independence can produce inaccurate -values when combining correlated -values, even when the -values are only weakly correlated. Therefore, to prevent from drawing false conclusions during hypothesis testing, our study advises caution be used when interpreting the -value obtained from combining -values of unknown correlation. However, when the correlation information is available, the weighting-capable statistical method, first introduced by Brown and recently modified by Hou, seems to perform the best amongst the methods investigated. PMID:24663491

Patterns of Work Values Held by Secondary School Girls.

ERIC Educational Resources Information Center

Wearne, T. David; And Others

1980-01-01

The work values of 541 high school girls did not vary significantly from grade to grade. The girls valued security, achievement, and the "good life" the most and valued management, intellectual stimulation, and esthetics the least. (SB)

Arbitrarily small amounts of correlation for arbitrarily varying quantum channels

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

Boche, H., E-mail: boche@tum.de, E-mail: janis.noetzel@tum.de; Nötzel, J., E-mail: boche@tum.de, E-mail: janis.noetzel@tum.de

2013-11-15

As our main result show that in order to achieve the randomness assisted message and entanglement transmission capacities of a finite arbitrarily varying quantum channel it is not necessary that sender and receiver share (asymptotically perfect) common randomness. Rather, it is sufficient that they each have access to an unlimited amount of uses of one part of a correlated bipartite source. This access might be restricted to an arbitrary small (nonzero) fraction per channel use, without changing the main result. We investigate the notion of common randomness. It turns out that this is a very costly resource – generically, itmore » cannot be obtained just by local processing of a bipartite source. This result underlines the importance of our main result. Also, the asymptotic equivalence of the maximal- and average error criterion for classical message transmission over finite arbitrarily varying quantum channels is proven. At last, we prove a simplified symmetrizability condition for finite arbitrarily varying quantum channels.« less

16 CFR 460.20 - R-value per inch claims.

Code of Federal Regulations, 2010 CFR

2010-01-01

...-values per inch of your product does not drop as it gets thicker. You can list a range of R-value per... add this statement: “The R-value per inch of this insulation varies with thickness. The thicker the...

Scaling Reward Value with Demand Curves versus Preference Tests

PubMed Central

Schwartz, Lindsay P.; Silberberg, Alan; Casey, Anna H.; Paukner, Annika; Suomi, Stephen J.

2016-01-01

In Experiment 1, six capuchins lifted a weight during a 10-minute session to receive a food piece. Across conditions, the weight was increased across six different amounts for three different food types. The number of food pieces obtained as a function of the weight lifted was fitted by a demand equation that is hypothesized to quantify food value. For most subjects, this analysis showed that the three food types differed little in value. In Experiment 2, these monkeys were given pairwise choices among these food types. In 13 of 18 comparisons, preferences at least equaled a 3-to-1 ratio; in seven comparisons, preference was absolute. There was no relation between values based on degree of preference versus values based on the demand equation. When choices in the present report were compared to similar data with these subjects from another study, between-study lability in preference emerged. This outcome contrasts with the finding in demand analysis that test-retest reliability is high. We attribute the unreliability and extreme assignment of value based on preference tests to high substitutability between foods. We suggest use of demand analysis instead of preference tests for studies that compare the values of different foods. A better strategy might be to avoid manipulating value by using different foods. Where possible, value should be manipulated by varying amounts of a single food type because, over an appropriate range, more food is consistently more valuable than less. Such an approach would be immune to problems in between-food substitutability. PMID:26908005

Smoothly varying in-plane stiffness heterogeneity evaluated under uniaxial tensile stress

Treesearch

J.M. Considine; F. Pierron; K.T. Turner; P. Lava; X. Tang

2017-01-01

Identification of spatially varying stiffness is a challenging, but important, research topic in the mechanics of materials and can provide the necessary information for material suitability, damage, and process control, especially for high‐value applications. One homogeneous and 3 heterogeneous virtual field method (VFM) formulations were used to create a methodology...

Comparison of Geant4-DNA simulation of S-values with other Monte Carlo codes

NASA Astrophysics Data System (ADS)

André, T.; Morini, F.; Karamitros, M.; Delorme, R.; Le Loirec, C.; Campos, L.; Champion, C.; Groetz, J.-E.; Fromm, M.; Bordage, M.-C.; Perrot, Y.; Barberet, Ph.; Bernal, M. A.; Brown, J. M. C.; Deleuze, M. S.; Francis, Z.; Ivanchenko, V.; Mascialino, B.; Zacharatou, C.; Bardiès, M.; Incerti, S.

2014-01-01

Monte Carlo simulations of S-values have been carried out with the Geant4-DNA extension of the Geant4 toolkit. The S-values have been simulated for monoenergetic electrons with energies ranging from 0.1 keV up to 20 keV, in liquid water spheres (for four radii, chosen between 10 nm and 1 μm), and for electrons emitted by five isotopes of iodine (131, 132, 133, 134 and 135), in liquid water spheres of varying radius (from 15 μm up to 250 μm). The results have been compared to those obtained from other Monte Carlo codes and from other published data. The use of the Kolmogorov-Smirnov test has allowed confirming the statistical compatibility of all simulation results.

Maximum group velocity in a one-dimensional model with a sinusoidally varying staggered potential

NASA Astrophysics Data System (ADS)

Nag, Tanay; Sen, Diptiman; Dutta, Amit

2015-06-01

We use Floquet theory to study the maximum value of the stroboscopic group velocity in a one-dimensional tight-binding model subjected to an on-site staggered potential varying sinusoidally in time. The results obtained by numerically diagonalizing the Floquet operator are analyzed using a variety of analytical schemes. In the low-frequency limit we use adiabatic theory, while in the high-frequency limit the Magnus expansion of the Floquet Hamiltonian turns out to be appropriate. When the magnitude of the staggered potential is much greater or much less than the hopping, we use degenerate Floquet perturbation theory; we find that dynamical localization occurs in the former case when the maximum group velocity vanishes. Finally, starting from an "engineered" initial state where the particles (taken to be hard-core bosons) are localized in one part of the chain, we demonstrate that the existence of a maximum stroboscopic group velocity manifests in a light-cone-like spreading of the particles in real space.

The amount effect and marginal value.

PubMed

Rachlin, Howard; Arfer, Kodi B; Safin, Vasiliy; Yen, Ming

2015-07-01

The amount effect of delay discounting (by which the value of larger reward amounts is discounted by delay at a lower rate than that of smaller amounts) strictly implies that value functions (value as a function of amount) are steeper at greater delays than they are at lesser delays. That is, the amount effect and the difference in value functions at different delays are actually a single empirical finding. Amount effects of delay discounting are typically found with choice experiments. Value functions for immediate rewards have been empirically obtained by direct judgment. (Value functions for delayed rewards have not been previously obtained.) The present experiment obtained value functions for both immediate and delayed rewards by direct judgment and found them to be steeper when the rewards were delayed--hence, finding an amount effect with delay discounting. © Society for the Experimental Analysis of Behavior.

A comparison of quality of present-day heat flow obtained from BHTs, Horner Plots of Malay Basin

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

Waples, D.W.; Mahadir, R.

1994-07-01

Reconciling temperature data obtained from measurement of single BHT, multiple BHT at a single depth, RFTs, and DSTs, is very difficult. Quality of data varied widely, however DST data were assumed to be most reliable. Data from 87 wells was used in this study, but only 47 wells have DST data. BASINMOD program was used to calculate the present-day heat flow, using measured thermal conductivity and calibrated against the DST data. The heat flows obtained from the DST data were assumed to be correct and representative throughout the basin. Then, heat flows using (1) uncorrected RFT data, (2) multiple BHTmore » data corrected by the Horner plot method, and (3) single BHT values corrected upward by a standard 10% were calculated. All of these three heat-flow populations had identically standard deviations to that for the DST data, but with significantly lower mean values. Correction factors were calculated to give each of the three erroneous populations the same mean value as the DST population. Heat flows calculated from RFT data had to be corrected upward by a factor of 1.12 to be equivalent to DST data; Horner plot data corrected by a factor of 1.18, and single BHT data by a factor of 1.2. These results suggest that present-day subsurface temperatures using RFT, Horner plot, and BHT data are considerably lower than they should be. The authors suspect qualitatively similar results would be found in other areas. Hence, they recommend significant corrections be routinely made until local calibration factors are established.« less

A VARI-Based Relative Greenness from MODIS Data for Computing the Fire Potential Index

NASA Technical Reports Server (NTRS)

Schneider, P.; Roberts, D. A.; Kyriakidis, P. C.

2008-01-01

The Fire Potential Index (FPI) relies on relative greenness (RG) estimates from remote sensing data. The Normalized Difference Vegetation index (NDVI), derived from NOAA Advanced Very High Resolution Radiometer (AVHRR) imagery is currently used to calculate RG operationally. Here we evaluated an alternate measure of RG using the Visible Atmospheric Resistant Index (VARI) derived from Moderate Resolution Imaging Spectrometer (MODIS) data. VARI was chosen because it has previously been shown to have the strongest relationship with Live Fuel Moisture (LFM) out of a wide selection of MODIS-derived indices in southern California shrublands. To compare MODIS-based NDVI-FPI and VARI-FPI, RG was calculated from a 6-year time series of MODIS composites and validated against in-situ observations of LFM as a surrogate for vegetation greenness. RG from both indices was then compared in terms of its performance for computing the FPI using historical wildfire data. Computed RG values were regressed against ground-sampled LFM at 14 sites within Los Angeles County. The results indicate the VARI-based RG consistently shows a stronger relationship with observed LFM than NDVI-based RG. With an average R2 of 0.727 compared to a value of only 0.622 for NDVI-RG, VARI-RG showed stronger relationships at 13 out of 14 sites. Based on these results, daily FPI maps were computed for the years 2001 through 2005 using both NDVI-RG and VARI-RG. These were then validated against 12,490 fire detections from the MODIS active fire product using logistic regression. Deviance of the logistic regression model was 408.8 for NDVI-FPI and 176.2 for VARI-FPI. The c-index was found to be 0.69 and 0.78, respectively. The results show that VARI-FP outperforms NDVI-FPI in distinguishing between fire and no-fire events for historical wildfire data in southern California for the given time period.

In-vitro evaluation of the accuracy of conventional and digital methods of obtaining full-arch dental impressions.

PubMed

Ender, Andreas; Mehl, Albert

2015-01-01

To investigate the accuracy of conventional and digital impression methods used to obtain full-arch impressions by using an in-vitro reference model. Eight different conventional (polyether, POE; vinylsiloxanether, VSE; direct scannable vinylsiloxanether, VSES; and irreversible hydrocolloid, ALG) and digital (CEREC Bluecam, CER; CEREC Omnicam, OC; Cadent iTero, ITE; and Lava COS, LAV) full-arch impressions were obtained from a reference model with a known morphology, using a highly accurate reference scanner. The impressions obtained were then compared with the original geometry of the reference model and within each test group. A point-to-point measurement of the surface of the model using the signed nearest neighbour method resulted in a mean (10%-90%)/2 percentile value for the difference between the impression and original model (trueness) as well as the difference between impressions within a test group (precision). Trueness values ranged from 11.5 μm (VSE) to 60.2 μm (POE), and precision ranged from 12.3 μm (VSE) to 66.7 μm (POE). Among the test groups, VSE, VSES, and CER showed the highest trueness and precision. The deviation pattern varied with the impression method. Conventional impressions showed high accuracy across the full dental arch in all groups, except POE and ALG. Conventional and digital impression methods show differences regarding full-arch accuracy. Digital impression systems reveal higher local deviations of the full-arch model. Digital intraoral impression systems do not show superior accuracy compared to highly accurate conventional impression techniques. However, they provide excellent clinical results within their indications applying the correct scanning technique.

Vibrational properties of gold nanoparticles obtained by green synthesis

NASA Astrophysics Data System (ADS)

Alvarez, Ramón A. B.; Cortez-Valadez, M.; Bueno, L. Oscar Neira; Britto Hurtado, R.; Rocha-Rocha, O.; Delgado-Beleño, Y.; Martinez-Nuñez, C. E.; Serrano-Corrales, Luis Ivan; Arizpe-Chávez, H.; Flores-Acosta, M.

2016-10-01

This study reports the synthesis and characterization of gold nanoparticles through an ecological method to obtain nanostructures from the extract of the plant Opuntia ficus-indica. Colloidal nanoparticles show sizes that vary between 10-20 nm, and present various geometric morphologies. The samples were characterized through optical absorption, Raman Spectroscopy and Transmission Electron Microscopy (TEM). Additionally, low energy metallic clusters of Aun (n=2-20 atoms) were modeled by computational quantum chemistry. The theoretical results were obtained with Density Functional Theory (DFT). The predicted results of Au clusters show a tendency and are correlated with the experimental results concerning the optical absorption bands and Raman spectroscopy in gold nanoparticles.

Human attitudes towards herpetofauna: the influence of folklore and negative values on the conservation of amphibians and reptiles in Portugal.

PubMed

Ceríaco, Luis Mp

2012-02-08

Human values and folklore of wildlife strongly influence the effectiveness of conservation efforts. These values and folklore may also vary with certain demographic characteristics such as gender, age, or education. Reptiles and amphibians are among the least appreciated of vertebrates and are victims of many negative values and wrong ideas resulting from the direct interpretation of folklore. We try to demonstrate how these values and folklore can affect the way people relate to them and also the possible conservation impacts on these animals. A questionnaire survey distributed to 514 people in the district of Évora, Portugal, was used to obtain data regarding the hypothesis that the existence of wrong ideas and negative values contributes to the phenomenon of human-associated persecution of these animals. A structural equation model was specified in order to confirm the hypothesis about the possible relationships between the presence of perceptions and negative values about amphibians and reptiles and persecution and anti-conservation attitudes. Sociodemographic variables were also added. The results of the model suggest that the presence of folklore and negative values clearly predicts persecution and anti-conservation attitudes towards amphibians and reptiles. Also, the existence of folklore varies sociodemographically, but negative values concerning these animals are widespread in the population. With the use of structural equation models, this work is a contribution to the study of how certain ideas and values can directly influence human attitudes towards herpetofauna and how they can be a serious conservation issue.

New exponential synchronization criteria for time-varying delayed neural networks with discontinuous activations.

PubMed

Cai, Zuowei; Huang, Lihong; Zhang, Lingling

2015-05-01

This paper investigates the problem of exponential synchronization of time-varying delayed neural networks with discontinuous neuron activations. Under the extended Filippov differential inclusion framework, by designing discontinuous state-feedback controller and using some analytic techniques, new testable algebraic criteria are obtained to realize two different kinds of global exponential synchronization of the drive-response system. Moreover, we give the estimated rate of exponential synchronization which depends on the delays and system parameters. The obtained results extend some previous works on synchronization of delayed neural networks not only with continuous activations but also with discontinuous activations. Finally, numerical examples are provided to show the correctness of our analysis via computer simulations. Our method and theoretical results have a leading significance in the design of synchronized neural network circuits involving discontinuous factors and time-varying delays. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Tentative Application Of Morphological Filters To Time-Varying Images

NASA Astrophysics Data System (ADS)

Billard, D.; Poquillon, B.

1989-03-01

In this paper, morphological filters, which are commonly used to process either 2D or multidimensional static images, are generalized to the analysis of time-varying image sequence. The introduction of the time dimension induces then interesting prop-erties when designing such spatio-temporal morphological filters. In particular, the specification of spatio-temporal structuring ele-ments (equivalent to time-varying spatial structuring elements) can be adjusted according to the temporal variations of the image sequences to be processed : this allows to derive specific morphological transforms to perform noise filtering or moving objects discrimination on dynamic images viewed by a non-stationary sensor. First, a brief introduction to the basic principles underlying morphological filters will be given. Then, a straightforward gener-alization of these principles to time-varying images will be pro-posed. This will lead us to define spatio-temporal opening and closing and to introduce some of their possible applications to process dynamic images. At last, preliminary results obtained us-ing a natural forward looking infrared (FUR) image sequence are presented.

Models of consumer value cocreation in health care.

PubMed

Nambisan, Priya; Nambisan, Satish

2009-01-01

In recent years, consumer participation in health care has gained critical importance as health care organizations (HCOs) seek varied avenues to enhance the quality and the value of their offerings. Many large HCOs have established online health communities where health care consumers (patients) can interact with one another to share knowledge and offer emotional support in disease management and care. Importantly, the focus of consumer participation in health care has moved beyond such personal health care management as the potential for consumers to participate in innovation and value creation in varied areas of the health care industry becomes increasingly evident. Realizing such potential, however, will require HCOs to develop a better understanding of the varied types of consumer value cocreation that are enabled by new information and communication technologies such as online health communities and Web 2.0 (social media) technologies. This article seeks to contribute toward such an understanding by offering a concise and coherent theoretical framework to analyze consumer value cocreation in health care. We identify four alternate models of consumer value cocreation-the partnership model, the open-source model, the support-group model, and the diffusion model-and discuss their implications for HCOs. We develop our theoretical framework by drawing on theories and concepts in knowledge creation, innovation management, and online communities. A set of propositions are developed by combining theoretical insights from these areas with real-world examples of consumer value cocreation in health care. The theoretical framework offered here informs on the potential impact of the different models of consumer value cocreation on important organizational variables such as innovation cost and time, service quality, and consumer perceptions of HCO. An understanding of the four models of consumer value cocreation can help HCOs adopt appropriate strategies and practices to

Budgerigar flight in a varying environment: flight at distinct speeds?

PubMed

Schiffner, Ingo; Srinivasan, Mandyam V

2016-06-01

How do flying birds respond to changing environments? The behaviour of budgerigars, Melopsittacus undulatus, was filmed as they flew through a tapered tunnel. Unlike flying insects-which vary their speed progressively and continuously by holding constant the optic flow induced by the walls-the birds showed a tendency to fly at only two distinct, fixed speeds. They switched between a high speed in the wider section of the tunnel, and a low speed in the narrower section. The transition between the two speeds was abrupt, and anticipatory. The high speed was close to the energy-efficient, outdoor cruising speed for these birds, while the low speed was approximately half this value. This is the first observation of the existence of two distinct, preferred flight speeds in birds. A dual-speed flight strategy may be beneficial for birds that fly in varying environments, with the high speed set at an energy-efficient value for flight through open spaces, and the low speed suited to safe manoeuvring in a cluttered environment. The constancy of flight speed within each regime enables the distances of obstacles and landmarks to be directly calibrated in terms of optic flow, thus facilitating simple and efficient guidance of flight through changing environments. © 2016 The Author(s).

[Gas Concentration Measurement Based on the Integral Value of Absorptance Spectrum].

PubMed

Liu, Hui-jun; Tao, Shao-hua; Yang, Bing-chu; Deng, Hong-gui

2015-12-01

of the absorptance spectrum varied with temperature and the calculating error for the integral value fluctuates with ranges of temperature, in the gas measurement when we usd integral values of the absoptance spectrum, we should select a suitable temperature variation and obtain a more accurate measurement result.

Cloud overlapping parameter obtained from CloudSat/CALIPSO dataset and its application in AGCM with McICA scheme

NASA Astrophysics Data System (ADS)

Jing, Xianwen; Zhang, Hua; Peng, Jie; Li, Jiangnan; Barker, Howard W.

2016-03-01

Vertical decorrelation length (Lcf) as used to determine overlap of cloudy layers in GCMs was obtained from CloudSat/CALIPSO measurements, made between 2007 and 2010, and analyzed in terms of monthly means. Global distributions of Lcf were produced for several cross-sectional lengths. Results show that: Lcf over the tropical convective regions typically exceeds 2 km and shift meridionally with season; the smallest Lcf (< 1 km) tends to occur in regions dominated by marine stratiform clouds; Lcf for mid-to-high latitude continents of the Northern Hemisphere (NH) ranges from 5-6 km during winter to 2-3 km during summer; and there are marked differences between continental and oceanic values of Lcf in the mid-latitudes of the NH. These monthly-gridded, observationally-based values of Lcf data were then used by the Monte Carlo Independent Column Approximation (McICA) radiation routines within the Beijing Climate Center's GCM (BCC_AGCM2.0.1). Additionally, the GCM was run with two other descriptions of Lcf: one varied with latitude only, and the other was simply 2 km everywhere all the time. It is shown that using the observationally-based Lcf in the GCM led to local and seasonal changes in total cloud fraction and shortwave (longwave) cloud radiative effects that serve mostly to reduce model biases. This indicates that usage of Lcf that vary according to location and time has the potential to improve climate simulations.

Imaging b-value depth variations within the Cocos and Rivera plates at the Mexican subduction zone

NASA Astrophysics Data System (ADS)

Rodríguez-Pérez, Quetzalcoatl; Zuñiga, F. Ramón

2018-06-01

By a systematic mapping of the b-value along profiles perpendicular to the Mexican Wadati-Benioff zone, we obtained important characteristics pertaining the stress state and faulting style related to the subduction process. To this purpose, we used data from the earthquake catalog reported by the Servicio Sismologico Nacional (1988-2016). We investigate depth variations of the b-value for the Cocos and Rivera under North American plates interface, by a detailed analysis of 15 cross-sections. The obtained b-value profiles vary from 0.50 to 2.50, which nevertheless appear related to the faulting style and stress state. By comparing the locations and focal mechanism of the largest events with the b-values of the surrounding regions, our analysis corroborates the dependence of the b-value on the faulting style. Thrust events occur in regions of low and high b-value at depths <50 km. Normal-faulting events occur mainly in high b-value regions at all shallow (Z < 30 km) and intermediate depths (Z > 30 km), in agreement with global studies. These results support the hypothesis that differential stress processes may be behind the occurrence of the different faulting style. On the contrary, by analyzing the mean b-values for both types of faulting mechanism at each of the cross-sections, we found a significantly lower mean b-value related to normal faulting for those regions where the 8 (Mw 8.2) and 19 (Mw 7.1) September 2017 earthquakes occur. These results lead us to conclude that those regions experienced an increased stress state prone to the occurrence of normal-intraplate events. We also compare the b-value distribution with Vp and Q tomography studies obtaining a good correlation between them. We found evidence to relate b-value variations with subduction processes such as stress state due to tectonic and flexural conditions, and to a lesser extent to material heterogeneity and fluid dehydration.

Impulsive effect on global exponential stability of BAM fuzzy cellular neural networks with time-varying delays

NASA Astrophysics Data System (ADS)

Li, Kelin

2010-02-01

In this article, a class of impulsive bidirectional associative memory (BAM) fuzzy cellular neural networks (FCNNs) with time-varying delays is formulated and investigated. By employing delay differential inequality and M-matrix theory, some sufficient conditions ensuring the existence, uniqueness and global exponential stability of equilibrium point for impulsive BAM FCNNs with time-varying delays are obtained. In particular, a precise estimate of the exponential convergence rate is also provided, which depends on system parameters and impulsive perturbation intention. It is believed that these results are significant and useful for the design and applications of BAM FCNNs. An example is given to show the effectiveness of the results obtained here.

7 CFR 765.353 - Determining market value.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Determining market value. 765.353 Section 765.353... Determining market value. (a) Security proposed for disposition. (1) The Agency will obtain an appraisal of... estimated value is less than $25,000. (b) Security remaining after disposition. The Agency will obtain an...

Time-varying phononic crystals

NASA Astrophysics Data System (ADS)

Wright, Derek Warren

The primary objective of this thesis was to gain a deeper understanding of acoustic wave propagation in phononic crystals, particularly those that include materials whose properties can be varied periodically in time. This research was accomplished in three ways. First, a 2D phononic crystal was designed, created, and characterized. Its properties closely matched those determined through simulation. The crystal demonstrated band gaps, dispersion, and negative refraction. It served as a means of elucidating the practicalities of phononic crystal design and construction and as a physical verification of their more interesting properties. Next, the transmission matrix method for analyzing 1D phononic crystals was extended to include the effects of time-varying material parameters. The method was then used to provide a closed-form solution for the case of periodically time-varying material parameters. Some intriguing results from the use of the extended method include dramatically altered transmission properties and parametric amplification. New insights can be gained from the governing equations and have helped to identify the conditions that lead to parametric amplification in these structures. Finally, 2D multiple scattering theory was modified to analyze scatterers with time-varying material parameters. It is shown to be highly compatible with existing multiple scattering theories. It allows the total scattered field from a 2D time-varying phononic crystal to be determined. It was shown that time-varying material parameters significantly affect the phononic crystal transmission spectrum, and this was used to switch an incident monochromatic wave. Parametric amplification can occur under certain circumstances, and this effect was investigated using the closed-form solutions provided by the new 1D method. The complexity of the extended methods grows logarithmically as opposed linearly with existing methods, resulting in superior computational complexity for large

Prognostic Value of Coronary Flow Reserve Obtained on Dobutamine Stress Echocardiography and its Correlation with Target Heart Rate.

PubMed

Abreu, José Sebastião de; Rocha, Eduardo Arrais; Machado, Isadora Sucupira; Parahyba, Isabelle O; Rocha, Thais Brito; Paes, Fernando José Villar Nogueira; Diogenes, Tereza Cristina Pinheiro; Abreu, Marília Esther Benevides de; Farias, Ana Gardenia Liberato Ponte; Carneiro, Marcia Maria; Paes, José Nogueira

2017-05-01

Normal coronary flow velocity reserve (CFVR) (≥ 2) obtained in the left anterior descending coronary artery (LAD) from transthoracic echocardiography is associated with a good prognosis, but there is no study correlating CFVR with submaximal target heart rate (HR). To evaluate the prognostic value of CFVR obtained in the LAD of patients with preserved (>50%) left ventricular ejection fraction (LVEF) who completed a dobutamine stress echocardiography (DSE), considering target HR. Prospective study of patients with preserved LVEF and CFVR obtained in the LAD who completed DSE. In Group I (GI = 31), normal CFVR was obtained before achieving target HR, and, in Group II (GII = 28), after that. Group III (G III=24) reached target HR, but CFVR was abnormal. Death, acute coronary insufficiency, coronary intervention, coronary angiography without further intervention, and hospitalization were considered events. In 28 ± 4 months, there were 18 (21.6%) events: 6% (2/31) in GI, 18% (5/28) in GII, and 46% (11/24) in GIII. There were 4 (4.8%) deaths, 6 (7.2%) coronary interventions and 8 (9.6%) coronary angiographies without further intervention. In event-free survival by regression analysis, GIII had more events than GI (p < 0.001) and GII (p < 0.045), with no difference between GI and GII (p = 0.160). After adjustment, the only difference was between GIII and GI (p = 0.012). In patients with preserved LVEF and who completed their DSE, normal CFVR obtained before achieving target HR was associated with better prognosis. A reserva de velocidade de fluxo coronariano (RVFC) adequada (≥ 2) obtida na artéria descendente anterior (ADA) através do ecocardiograma transtorácico associa-se a bom prognóstico, mas não há estudo correlacionando-a com a frequência cardíaca (FC) alvo (submáxima). Avaliar o valor prognóstico da RVFC obtida na ADA de pacientes com fração de ejeção do ventrículo esquerdo (FEVE) preservada (>50%) e ecocardiograma sob estresse com dobutamina

Effectiveness of Prompts on Fourth-Grade Children's Dietary Recall Accuracy Depends on Retention Interval and Varies by Gender.

PubMed

Baxter, Suzanne D; Smith, Albert F; Hitchcock, David B; Guinn, Caroline H; Royer, Julie A; Collins, Kathleen L; Smith, Alyssa L; Puryear, Megan P; Vaadi, Kate K; Finney, Christopher J; Miller, Patricia H

2015-09-01

Dietary recall accuracy is related to retention interval (RI) (i.e., time between to-be-reported meals and the interview), and possibly to prompts. To the best of our knowledge, no study has evaluated their combined effect. The combined influence of RI and prompts on children's recall accuracy was investigated in this study. Two RIs [short (prior-24-h recall obtained in afternoon) and long (previous-day recall obtained in morning)] were crossed with 4 prompts [forward (distant-to-recent), meal-name (breakfast, lunch, etc.), open (no instructions), and reverse (recent-to-distant)], creating 8 conditions. Fourth-grade children (n = 480; 50% girls) were randomly selected from consenting children at 10 schools in 4 districts in a southern state during 3 school years (2011-2012, 2012-2013, and 2013-2014). Each child was observed eating school-provided breakfast and lunch, and interviewed one time under 1 of the 8 conditions. Condition assignment was constrained so that each had 60 children (30 girls). Accuracy measures were food-item omission and intrusion rates, and energy correspondence rate and inflation ratio. For each measure, linear models determined effects of RI, prompt, gender, and interactions (2-way, 3-way); race/ethnicity, school year, and district were control variables. RI (P values < 0.015) and prompt (P values < 0.005) were significant for all 4 accuracy measures. RI × prompt (P values < 0.001) was significant for 3 accuracy measures (not intrusion rate). Prompt × gender (P = 0.005) was significant for omission rate. RI × prompt × gender was significant for intrusion rate and inflation ratio (P values < 0.001). For the short vs. long RI across prompts and genders, accuracy was better by 33-50% for each accuracy measure. To obtain the most accurate recalls possible from children, studies should be designed to use a short rather than long RI. Prompts affect children's recall accuracy, although the effectiveness of different prompts depends on RI and

Hybrid value foraging: How the value of targets shapes human foraging behavior.

PubMed

Wolfe, Jeremy M; Cain, Matthew S; Alaoui-Soce, Abla

2018-04-01

In hybrid foraging, observers search visual displays for multiple instances of multiple target types. In previous hybrid foraging experiments, although there were multiple types of target, all instances of all targets had the same value. Under such conditions, behavior was well described by the marginal value theorem (MVT). Foragers left the current "patch" for the next patch when the instantaneous rate of collection dropped below their average rate of collection. An observer's specific target selections were shaped by previous target selections. Observers were biased toward picking another instance of the same target. In the present work, observers forage for instances of four target types whose value and prevalence can vary. If value is kept constant and prevalence manipulated, participants consistently show a preference for the most common targets. Patch-leaving behavior follows MVT. When value is manipulated, observers favor more valuable targets, though individual foraging strategies become more diverse, with some observers favoring the most valuable target types very strongly, sometimes moving to the next patch without collecting any of the less valuable targets.

Varying electric charge in multiscale spacetimes

NASA Astrophysics Data System (ADS)

Calcagni, Gianluca; Magueijo, João; Fernández, David Rodríguez

2014-01-01

We derive the covariant equations of motion for Maxwell field theory and electrodynamics in multiscale spacetimes with weighted Laplacian. An effective spacetime-dependent electric charge of geometric origin naturally emerges from the theory, thus giving rise to a varying fine-structure constant. The theory is compared with other varying-coupling models, such as those with a varying electric charge or varying speed of light. The theory is also confronted with cosmological observations, which can place constraints on the characteristic scales in the multifractional measure. We note that the model considered here is fundamentally different from those previously proposed in the literature, either of the varying-e or varying-c persuasion.

Memory, priority encoding, and overcoming high-value proactive interference in younger and older adults.

PubMed

Friedman, Michael C; Castel, Alan D

2013-01-01

It is often necessary to remember important information while directing attention away from encoding less valuable information. To examine how aging influences the ability to control and update the encoding of high-value information, younger and older adults studied six lists of words that varied in terms of the point values associated with each word. The words were paired with the same high and low point values for three study-test cycles, but on the fourth and subsequent cycles the value-word pairings were switched such that the lowest value pairs became the highest values (and vice versa). For the first three study-test cycles, younger adults outperformed older adults in terms of the number of words recalled and overall point totals, but performance was similar in terms of selectively remembering high-value words. When the values were switched, both groups displayed substantial interference from the previous pairings. Although both groups improved with additional study-test cycles, only younger adults were able to fully recover from the interference effects. A similar, and more pronounced, set of results were obtained when positive and negative point values were paired with the words. The findings are interpreted in a value-directed remembering framework, emphasizing the role of benefits and costs of strategic encoding and age-related differences in the effects of interference on memory.

Path Flow Estimation Using Time Varying Coefficient State Space Model

NASA Astrophysics Data System (ADS)

Jou, Yow-Jen; Lan, Chien-Lun

2009-08-01

The dynamic path flow information is very crucial in the field of transportation operation and management, i.e., dynamic traffic assignment, scheduling plan, and signal timing. Time-dependent path information, which is important in many aspects, is nearly impossible to be obtained. Consequently, researchers have been seeking estimation methods for deriving valuable path flow information from less expensive traffic data, primarily link traffic counts of surveillance systems. This investigation considers a path flow estimation problem involving the time varying coefficient state space model, Gibbs sampler, and Kalman filter. Numerical examples with part of a real network of the Taipei Mass Rapid Transit with real O-D matrices is demonstrated to address the accuracy of proposed model. Results of this study show that this time-varying coefficient state space model is very effective in the estimation of path flow compared to time-invariant model.

Human attitudes towards herpetofauna: The influence of folklore and negative values on the conservation of amphibians and reptiles in Portugal

PubMed Central

2012-01-01

Background Human values and folklore of wildlife strongly influence the effectiveness of conservation efforts. These values and folklore may also vary with certain demographic characteristics such as gender, age, or education. Reptiles and amphibians are among the least appreciated of vertebrates and are victims of many negative values and wrong ideas resulting from the direct interpretation of folklore. We try to demonstrate how these values and folklore can affect the way people relate to them and also the possible conservation impacts on these animals. Methods A questionnaire survey distributed to 514 people in the district of Évora, Portugal, was used to obtain data regarding the hypothesis that the existence of wrong ideas and negative values contributes to the phenomenon of human-associated persecution of these animals. A structural equation model was specified in order to confirm the hypothesis about the possible relationships between the presence of perceptions and negative values about amphibians and reptiles and persecution and anti-conservation attitudes. Sociodemographic variables were also added. Results The results of the model suggest that the presence of folklore and negative values clearly predicts persecution and anti-conservation attitudes towards amphibians and reptiles. Also, the existence of folklore varies sociodemographically, but negative values concerning these animals are widespread in the population. Conclusions With the use of structural equation models, this work is a contribution to the study of how certain ideas and values can directly influence human attitudes towards herpetofauna and how they can be a serious conservation issue. PMID:22316318

Diffusion-weighted MR imaging of the pancreas: optimizing b-value for visualization of pancreatic adenocarcinoma.

PubMed

Fukukura, Yoshihiko; Shindo, Toshikazu; Hakamada, Hiroto; Takumi, Koji; Umanodan, Tomokazu; Nakajo, Masanori; Kamimura, Kiyoshisa; Umanodan, Aya; Ideue, Junnichi; Yoshiura, Takashi

2016-10-01

To determine the optimal b-value of 3.0-T diffusion-weighted imaging (DWI) for visualizing pancreatic adenocarcinomas Fifty-five patients with histologically confirmed pancreatic adenocarcinoma underwent DWI with different b-values (b = 500, 1000, 1500, and 2000 s/mm(2)) at 3.0 T. For each b-value, we retrospectively evaluated DWI findings of pancreatic adenocarcinomas (clear hyperintensity relative to the surrounding pancreas, hyperintensity with an unclear distal border, and isointensity) and image quality, and measured tumour-to-pancreas signal intensity (SI) ratios. DWI findings, image quality, and tumour-to-pancreas SI ratios were compared between the four b-values. There was a significantly higher incidence of tumours showing clear hyperintensity on DWI with b-value of 1500 s/mm(2) than on that with b-value of 1000 s/mm(2) (P < 0.001), and on DWI with b-value of 1000 s/mm(2) than on that with b-value of 500 s/mm(2) (P < 0.001). The tumour-to-distal pancreas SI ratio was higher with b-value of 1500 s/mm(2) than with b-value of 1000 s/mm(2) (P < 0.001), and with b-value of 1000 s/mm(2) than with b-value of 500 s/mm(2) (P < 0.001). A lower image quality was obtained at increasing b-values (P < 0.001); the lowest scores were observed with b-value of 2000 s/mm(2). The use of b = 1500 s/mm(2) for 3.0-T DWI can improve the delineation of pancreatic adenocarcinomas. • Diffusion-weighted imaging (DWI) has been used for diagnosing pancreatic adenocarcinoma • The techniques for DWI, including the choice of b-values, vary considerably • DWI often fails to delineate pancreatic adenocarcinomas because of hyperintense pancreas • DWI with a higher b-value can improve the tumour delineation • The lowest image quality was obtained on DWI with b-value = 2000 s/mm (2).

A simple strategy for varying the restart parameter in GMRES(m)

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

Baker, A H; Jessup, E R; Kolev, T V

2007-10-02

When solving a system of linear equations with the restarted GMRES method, a fixed restart parameter is typically chosen. We present numerical experiments that demonstrate the beneficial effects of changing the value of the restart parameter in each restart cycle on the total time to solution. We propose a simple strategy for varying the restart parameter and provide some heuristic explanations for its effectiveness based on analysis of the symmetric case.

Preference-based measures to obtain health state utility values for use in economic evaluations with child-based populations: a review and UK-based focus group assessment of patient and parent choices.

PubMed

Wolstenholme, Jane L; Bargo, Danielle; Wang, Kay; Harnden, Anthony; Räisänen, Ulla; Abel, Lucy

2018-03-21

No current guidance is available in the UK on the choice of preference-based measure (PBM) that should be used in obtaining health-related quality of life from children. The aim of this study is to review the current usage of PBMs for obtaining health state utility values in child and adolescent populations, and to obtain information on patient and parent-proxy respondent preferences in completing PBMs in the UK. A literature review was conducted to determine which instrument is most frequently used for child-based economic evaluations and whether child or proxy responses are used. Instruments were compared on dimensions, severity levels, elicitation and valuation methods, availability of value sets and validation studies, and the range of utility values generated. Additionally, a series of focus groups of parents and young people (11-20 years) were convened to determine patient and proxy preferences. Five PBMs suitable for child populations were identified, although only the Health Utilities Index 2 (HUI2) and Child Heath Utility 9D (CHU-9D) have UK value sets. 45 papers used PBMs in this population, but many used non-child-specific PBMs. Most respondents were parent proxies, even in adolescent populations. Reported missing data ranged from 0.5 to 49.3%. The focus groups reported their experiences with the EQ-5D-Y and CHU-9D. Both the young persons' group and parent/proxy groups felt that the CHU-9D was more comprehensive but may be harder for a proxy to complete. Some younger children had difficulty understanding the CHU-9D questions, but the young persons' group nonetheless preferred responding directly. The use of PBMs in child populations is increasing, but many studies use PBMs that do not have appropriate value sets. Parent proxies are the most common respondents, but the focus group responses suggest it would be preferred, and may be more informative, for older children to self-report or for child-parent dyads to respond.

Existence and global exponential stability of periodic solution of memristor-based BAM neural networks with time-varying delays.

PubMed

Li, Hongfei; Jiang, Haijun; Hu, Cheng

2016-03-01

In this paper, we investigate a class of memristor-based BAM neural networks with time-varying delays. Under the framework of Filippov solutions, boundedness and ultimate boundedness of solutions of memristor-based BAM neural networks are guaranteed by Chain rule and inequalities technique. Moreover, a new method involving Yoshizawa-like theorem is favorably employed to acquire the existence of periodic solution. By applying the theory of set-valued maps and functional differential inclusions, an available Lyapunov functional and some new testable algebraic criteria are derived for ensuring the uniqueness and global exponential stability of periodic solution of memristor-based BAM neural networks. The obtained results expand and complement some previous work on memristor-based BAM neural networks. Finally, a numerical example is provided to show the applicability and effectiveness of our theoretical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

Organic particulate matter formation at varying relative humidity using surrogate secondary and primary organic compounds with activity corrections in the condensed phase obtained using a method based on the Wilson equation

NASA Astrophysics Data System (ADS)

Chang, E. I.; Pankow, J. F.

2008-01-01

Secondary organic aerosol (SOA) formation in the atmosphere is currently often modeled using a multiple lumped "two-product" (N·2p) approach. The N·2p approach neglects: 1) variation of activity coefficient (ζi) values and mean molecular weight MW in the particulate matter (PM) phase; 2) water uptake into the PM; and 3) the possibility of phase separation in the PM. This study considers these effects by adopting an (N·2p)ζ, MW ,θ approach (θ is a phase index). Specific chemical structures are assigned to 25 lumped SOA compounds and to 15 representative primary organic aerosol (POA) compounds to allow calculation of ζi and MW values. The SOA structure assignments are based on chamber-derived 2p gas/particle partition coefficient values coupled with known effects of structure on vapor pressure pL,i° (atm). To facilitate adoption of the (N·2p)ζ, MW, θ approach in large-scale models, this study also develops CP-Wilson.1, a group-contribution ζi-prediction method that is more computationally economical than the UNIFAC model of Fredenslund et al. (1975). Group parameter values required by CP-Wilson.1 are obtained by fitting ζi values to predictions from UNIFAC. The (N·2p)ζ,MW, θ approach is applied (using CP-Wilson.1) to several real α-pinene/O3 chamber cases for high reacted hydrocarbon levels (ΔHC≍400 to 1000 μg m-3) when relative humidity (RH) ≍50%. Good agreement between the chamber and predicted results is obtained using both the (N·2p)ζ, MW, θ and N·2p approaches, indicating relatively small water effects under these conditions. However, for a hypothetical α-pinene/O3 case at �

Line-driven winds revisited in the context of Be stars: Ω-slow solutions with high k values

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

Silaj, J.; Jones, C. E.; Curé, M.

2014-11-01

The standard, or fast, solutions of m-CAK line-driven wind theory cannot account for slowly outflowing disks like the ones that surround Be stars. It has been previously shown that there exists another family of solutions—the Ω-slow solutions—that is characterized by much slower terminal velocities and higher mass-loss rates. We have solved the one-dimensional m-CAK hydrodynamical equation of rotating radiation-driven winds for this latter solution, starting from standard values of the line force parameters (α, k, and δ), and then systematically varying the values of α and k. Terminal velocities and mass-loss rates that are in good agreement with those foundmore » in Be stars are obtained from the solutions with lower α and higher k values. Furthermore, the equatorial densities of such solutions are comparable to those that are typically assumed in ad hoc models. For very high values of k, we find that the wind solutions exhibit a new kind of behavior.« less

Individual preferences modulate incentive values: Evidence from functional MRI

PubMed Central

Koeneke, Susan; Pedroni, Andreas F; Dieckmann, Anja; Bosch, Volker; Jäncke, Lutz

2008-01-01

Background In most studies on human reward processing, reward intensity has been manipulated on an objective scale (e.g., varying monetary value). Everyday experience, however, teaches us that objectively equivalent rewards may differ substantially in their subjective incentive values. One factor influencing incentive value in humans is branding. The current study explores the hypothesis that individual brand preferences modulate activity in reward areas similarly to objectively measurable differences in reward intensity. Methods A wheel-of-fortune game comprising an anticipation phase and a subsequent outcome evaluation phase was implemented. Inside a 3 Tesla MRI scanner, 19 participants played for chocolate bars of three different brands that differed in subjective attractiveness. Results Parametrical analysis of the obtained fMRI data demonstrated that the level of activity in anatomically distinct neural networks was linearly associated with the subjective preference hierarchy of the brands played for. During the anticipation phases, preference-dependent neural activity has been registered in premotor areas, insular cortex, orbitofrontal cortex, and in the midbrain. During the outcome phases, neural activity in the caudate nucleus, precuneus, lingual gyrus, cerebellum, and in the pallidum was influenced by individual preference. Conclusion Our results suggest a graded effect of differently preferred brands onto the incentive value of objectively equivalent rewards. Regarding the anticipation phase, the results reflect an intensified state of wanting that facilitates action preparation when the participants play for their favorite brand. This mechanism may underlie approach behavior in real-life choice situations. PMID:19032746

Decreased value-sensitivity in schizophrenia.

PubMed

Martinelli, Cristina; Rigoli, Francesco; Dolan, Ray J; Shergill, Sukhwinder S

2018-01-01

Pathophysiology in schizophrenia has been linked to aberrant incentive salience, namely the dysfunctional processing of value linked to abnormal dopaminergic activity. In line with this, recent studies showed impaired learning of value in schizophrenia. However, how value is used to guide behaviour independently from learning, as in risky choice, has rarely been examined in this disorder. We studied value-guided choice under risk in patients with schizophrenia and in controls using a task requiring a choice between a certain monetary reward, varying trial-by-trial, and a gamble offering an equal probability of getting double this certain amount or nothing. We observed that patients compared to controls exhibited reduced sensitivity to values, implying that their choices failed to flexibly adapt to the specific values on offer. Moreover, the degree of this value sensitivity inversely correlated with aberrant salience experience, suggesting that the inability to tune choice to value may be a key element of aberrant salience in the illness. Our results help clarify the cognitive mechanisms underlying improper attribution of value in schizophrenia and may thus inform cognitive interventions aimed at reinstating value sensitivity in patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Timber value growth rates in New England

Treesearch

David A, Gansner; Stanford L. Arner; Thomas W. Birch; Thomas W. Birch

1990-01-01

Rates of growth in the value of standing timber can vary greatly from stand to stand and from tree to tree. In Maine, the compound annual rate of change in stand value between the two most recent forest inventories ranged from -12 to +43 percent. Faced with this kind of variation, forest managers can use help in determining financial rates of return for their woodland...

Shape and Spatially-Varying Reflectance Estimation from Virtual Exemplars.

PubMed

Hui, Zhuo; Sankaranarayanan, Aswin C

2017-10-01

This paper addresses the problem of estimating the shape of objects that exhibit spatially-varying reflectance. We assume that multiple images of the object are obtained under a fixed view-point and varying illumination, i.e., the setting of photometric stereo. At the core of our techniques is the assumption that the BRDF at each pixel lies in the non-negative span of a known BRDF dictionary. This assumption enables a per-pixel surface normal and BRDF estimation framework that is computationally tractable and requires no initialization in spite of the underlying problem being non-convex. Our estimation framework first solves for the surface normal at each pixel using a variant of example-based photometric stereo. We design an efficient multi-scale search strategy for estimating the surface normal and subsequently, refine this estimate using a gradient descent procedure. Given the surface normal estimate, we solve for the spatially-varying BRDF by constraining the BRDF at each pixel to be in the span of the BRDF dictionary; here, we use additional priors to further regularize the solution. A hallmark of our approach is that it does not require iterative optimization techniques nor the need for careful initialization, both of which are endemic to most state-of-the-art techniques. We showcase the performance of our technique on a wide range of simulated and real scenes where we outperform competing methods.

Valuing wetland attributes in the Lake Champlain Basin

Treesearch

Donald F. Dennis; Walter F. Kuentzel

1998-01-01

This research explores the use of conjoint analysis to assess and understand wetland values. A conjoint rating survey was designed and mailed to landowners in the Laplatte River Basin (Lake Champlain) in Vermont. Landowners rated options to protect wetlands that varied by the wetland's ability to decrease pollutants entering Lake Champlain, value in providing food...

Meaning That Social Studies Teacher Candidates Give to Value Concept and Their Value Rankings

ERIC Educational Resources Information Center

Aysegül, Tural

2018-01-01

This work determines the role that value education plays in shaping people's personal and social life. This research aims to put forward meaning that social studies teacher candidates give to value concept and its value ranking. To achieve this aim, the opinions of 12 social studies teacher candidates were obtained. During the data collection…

Time-varying Concurrent Risk of Extreme Droughts and Heatwaves in California

NASA Astrophysics Data System (ADS)

Sarhadi, A.; Diffenbaugh, N. S.; Ausin, M. C.

2016-12-01

Anthropogenic global warming has changed the nature and the risk of extreme climate phenomena such as droughts and heatwaves. The concurrent of these nature-changing climatic extremes may result in intensifying undesirable consequences in terms of human health and destructive effects in water resources. The present study assesses the risk of concurrent extreme droughts and heatwaves under dynamic nonstationary conditions arising from climate change in California. For doing so, a generalized fully Bayesian time-varying multivariate risk framework is proposed evolving through time under dynamic human-induced environment. In this methodology, an extreme, Bayesian, dynamic copula (Gumbel) is developed to model the time-varying dependence structure between the two different climate extremes. The time-varying extreme marginals are previously modeled using a Generalized Extreme Value (GEV) distribution. Bayesian Markov Chain Monte Carlo (MCMC) inference is integrated to estimate parameters of the nonstationary marginals and copula using a Gibbs sampling method. Modelled marginals and copula are then used to develop a fully Bayesian, time-varying joint return period concept for the estimation of concurrent risk. Here we argue that climate change has increased the chance of concurrent droughts and heatwaves over decades in California. It is also demonstrated that a time-varying multivariate perspective should be incorporated to assess realistic concurrent risk of the extremes for water resources planning and management in a changing climate in this area. The proposed generalized methodology can be applied for other stochastic nature-changing compound climate extremes that are under the influence of climate change.

[Analysis of chromatic value of gingival porcelain].

PubMed

Wang, Min; Sun, Jun; Chao, Yong-Lie

2005-08-01

To study the distribution of the chromatic value of gingival porcelains. The color change of Shofu VINTAGE and Vita VMK95 gingival porcelains on the black and white backings was determined with a spectrophotometer (PR-650). The results showed that the chromatic value of gingival porcelains was different on varying backings. The color space of gingival porcelain was L*: 41.85 - 50.64, a*: 12.46 - 19.46, b*: 1.33 - 4.62. The chromatic value distribution cannot cover the color region of natural gingiva.

An MHD simulation model of time-dependent global solar corona with temporally varying solar-surface magnetic field maps

NASA Astrophysics Data System (ADS)

Hayashi, K.

2013-11-01

We present a model of a time-dependent three-dimensional magnetohydrodynamics simulation of the sub-Alfvenic solar corona and super-Alfvenic solar wind with temporally varying solar-surface boundary magnetic field data. To (i) accommodate observational data with a somewhat arbitrarily evolving solar photospheric magnetic field as the boundary value and (ii) keep the divergence-free condition, we developed a boundary model, here named Confined Differential Potential Field model, that calculates the horizontal components of the magnetic field, from changes in the vertical component, as a potential field confined in a thin shell. The projected normal characteristic method robustly simulates the solar corona and solar wind, in response to the temporal variation of the boundary Br. We conduct test MHD simulations for two periods, from Carrington Rotation number 2009 to 2010 and from Carrington Rotation 2074 to 2075 at solar maximum and minimum of Cycle 23, respectively. We obtained several coronal features that a fixed boundary condition cannot yield, such as twisted magnetic field lines at the lower corona and the transition from an open-field coronal hole to a closed-field streamer. We also obtained slight improvements of the interplanetary magnetic field, including the latitudinal component, at Earth.

Holographic cinematography of time-varying reflecting and time-varying phase objects using a Nd:YAG laser.

PubMed

Decker, A J

1982-03-01

The use of a Nd:YAG laser to record holographic motion pictures of time-varying reflecting objects and time-varying phase objects is discussed. Sample frames from both types of holographic motion pictures are presented. The holographic system discussed is intended for three-dimensional flow visualization of the time-varying flows that occur in jet-engine components.

Holographic cinematography of time-varying reflecting and time-varying phase objects using a Nd:YAG laser

NASA Technical Reports Server (NTRS)

Decker, A. J.

1982-01-01

The use of a Nd:YAG laser to record holographic motion pictures of time-varying reflecting objects and time-varying phase objects is discussed. Sample frames from both types of holographic motion pictures are presented. The holographic system discussed is intended for three-dimensional flow visualization of the time-varying flows that occur in jet-engine components.

Dopamine prediction error responses integrate subjective value from different reward dimensions

PubMed Central

Lak, Armin; Stauffer, William R.; Schultz, Wolfram

2014-01-01

Prediction error signals enable us to learn through experience. These experiences include economic choices between different rewards that vary along multiple dimensions. Therefore, an ideal way to reinforce economic choice is to encode a prediction error that reflects the subjective value integrated across these reward dimensions. Previous studies demonstrated that dopamine prediction error responses reflect the value of singular reward attributes that include magnitude, probability, and delay. Obviously, preferences between rewards that vary along one dimension are completely determined by the manipulated variable. However, it is unknown whether dopamine prediction error responses reflect the subjective value integrated from different reward dimensions. Here, we measured the preferences between rewards that varied along multiple dimensions, and as such could not be ranked according to objective metrics. Monkeys chose between rewards that differed in amount, risk, and type. Because their choices were complete and transitive, the monkeys chose “as if” they integrated different rewards and attributes into a common scale of value. The prediction error responses of single dopamine neurons reflected the integrated subjective value inferred from the choices, rather than the singular reward attributes. Specifically, amount, risk, and reward type modulated dopamine responses exactly to the extent that they influenced economic choices, even when rewards were vastly different, such as liquid and food. This prediction error response could provide a direct updating signal for economic values. PMID:24453218

Skyrmion dynamics in width-varying nanotracks and implications for skyrmionic applications

NASA Astrophysics Data System (ADS)

Chen, Xing; Kang, Wang; Zhu, Daoqian; Zhang, Xichao; Lei, Na; Zhang, Youguang; Zhou, Yan; Zhao, Weisheng

2017-11-01

A comprehensive study of the magnetic skyrmion dynamics in terms of size, velocity, energy, and stability in width-varying nanotracks is reported by micromagnetic simulations. We find that the diameter of a skyrmion reduces with the decrease in the nanotrack width in the spin Hall effect (SHE)-induced skyrmion motion. Accordingly, the skyrmion energy increases giving rise to the growing instability of the skyrmion. It is also numerically demonstrated that the velocity of the skyrmion varies during the motion, since the repulsive force of the nanotrack edges acting on the skyrmion as well as the driving force created by the SHE associated with the size of the skyrmion have a joint impact on the skyrmion motion dynamics in the width-varying nanotrack. In addition, one interesting finding reveals that skyrmions with small sizes, which may be inaccessible to typical approaches by means of directly injecting a spin-polarized current, could be obtained by utilizing this structure. This finding is potential for generating nanoscale skyrmions in skyrmionic applications with ultra-dense density. Finally, inspired by the skyrmion dynamics in the width-varying nanotrack, a general summary on the tradeoff between the nanotrack width (storage density) and the skyrmion velocity (data access speed) is given by further analyzing the skyrmion dynamics in parallel nanotracks with different widths, which may provide guidelines in designing racetrack-type skyrmionic applications.

Robust stability for uncertain stochastic fuzzy BAM neural networks with time-varying delays

NASA Astrophysics Data System (ADS)

Syed Ali, M.; Balasubramaniam, P.

2008-07-01

In this Letter, by utilizing the Lyapunov functional and combining with the linear matrix inequality (LMI) approach, we analyze the global asymptotic stability of uncertain stochastic fuzzy Bidirectional Associative Memory (BAM) neural networks with time-varying delays which are represented by the Takagi-Sugeno (TS) fuzzy models. A new class of uncertain stochastic fuzzy BAM neural networks with time varying delays has been studied and sufficient conditions have been derived to obtain conservative result in stochastic settings. The developed results are more general than those reported in the earlier literatures. In addition, the numerical examples are provided to illustrate the applicability of the result using LMI toolbox in MATLAB.

Time-varying BRDFs.

PubMed

Sun, Bo; Sunkavalli, Kalyan; Ramamoorthi, Ravi; Belhumeur, Peter N; Nayar, Shree K

2007-01-01

The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying. However, none of the existing BRDF models and databases take time variation into consideration; they represent the appearance of a material at a single time instance. In this paper, we address the acquisition, analysis, modeling, and rendering of a wide range of time-varying BRDFs (TVBRDFs). We have developed an acquisition system that is capable of sampling a material's BRDF at multiple time instances, with each time sample acquired within 36 sec. We have used this acquisition system to measure the BRDFs of a wide range of time-varying phenomena, which include the drying of various types of paints (watercolor, spray, and oil), the drying of wet rough surfaces (cement, plaster, and fabrics), the accumulation of dusts (household and joint compound) on surfaces, and the melting of materials (chocolate). Analytic BRDF functions are fit to these measurements and the model parameters' variations with time are analyzed. Each category exhibits interesting and sometimes nonintuitive parameter trends. These parameter trends are then used to develop analytic TVBRDF models. The analytic TVBRDF models enable us to apply effects such as paint drying and dust accumulation to arbitrary surfaces and novel materials.

Quantifying time-varying cellular secretions with local linear models.

PubMed

Byers, Jeff M; Christodoulides, Joseph A; Delehanty, James B; Raghu, Deepa; Raphael, Marc P

2017-07-01

Extracellular protein concentrations and gradients initiate a wide range of cellular responses, such as cell motility, growth, proliferation and death. Understanding inter-cellular communication requires spatio-temporal knowledge of these secreted factors and their causal relationship with cell phenotype. Techniques which can detect cellular secretions in real time are becoming more common but generalizable data analysis methodologies which can quantify concentration from these measurements are still lacking. Here we introduce a probabilistic approach in which local-linear models and the law of mass action are applied to obtain time-varying secreted concentrations from affinity-based biosensor data. We first highlight the general features of this approach using simulated data which contains both static and time-varying concentration profiles. Next we apply the technique to determine concentration of secreted antibodies from 9E10 hybridoma cells as detected using nanoplasmonic biosensors. A broad range of time-dependent concentrations was observed: from steady-state secretions of 230 pM near the cell surface to large transients which reached as high as 56 nM over several minutes and then dissipated.

Emotions in freely varying and mono-pitched vowels, acoustic and EGG analyses.

PubMed

Waaramaa, Teija; Palo, Pertti; Kankare, Elina

2015-12-01

Vocal emotions are expressed either by speech or singing. The difference is that in singing the pitch is predetermined while in speech it may vary freely. It was of interest to study whether there were voice quality differences between freely varying and mono-pitched vowels expressed by professional actors. Given their profession, actors have to be able to express emotions both by speech and singing. Electroglottogram and acoustic analyses of emotional utterances embedded in expressions of freely varying vowels [a:], [i:], [u:] (96 samples) and mono-pitched protracted vowels (96 samples) were studied. Contact quotient (CQEGG) was calculated using 35%, 55%, and 80% threshold levels. Three different threshold levels were used in order to evaluate their effects on emotions. Genders were studied separately. The results suggested significant gender differences for CQEGG 80% threshold level. SPL, CQEGG, and F4 were used to convey emotions, but to a lesser degree, when F0 was predetermined. Moreover, females showed fewer significant variations than males. Both genders used more hypofunctional phonation type in mono-pitched utterances than in the expressions with freely varying pitch. The present material warrants further study of the interplay between CQEGG threshold levels and formant frequencies, and listening tests to investigate the perceptual value of the mono-pitched vowels in the communication of emotions.

Normal Values of Tissue-Muscle Perfusion Indexes of Lower Limbs Obtained with a Scintigraphic Method.

PubMed

Manevska, Nevena; Stojanoski, Sinisa; Pop Gjorceva, Daniela; Todorovska, Lidija; Miladinova, Daniela; Zafirova, Beti

2017-09-01

Introduction Muscle perfusion is a physiologic process that can undergo quantitative assessment and thus define the range of normal values of perfusion indexes and perfusion reserve. The investigation of the microcirculation has a crucial role in determining the muscle perfusion. Materials and method The study included 30 examinees, 24-74 years of age, without a history of confirmed peripheral artery disease and all had normal findings on Doppler ultrasonography and pedo-brachial index of lower extremity (PBI). 99mTc-MIBI tissue muscle perfusion scintigraphy of lower limbs evaluates tissue perfusion in resting condition "rest study" and after workload "stress study", through quantitative parameters: Inter-extremity index (for both studies), left thigh/right thigh (LT/RT) left calf/right calf (LC/RC) and perfusion reserve (PR) for both thighs and calves. Results In our investigated group we assessed the normal values of quantitative parameters of perfusion indexes. Indexes ranged for LT/RT in rest study 0.91-1.05, in stress study 0.92-1.04. LC/RC in rest 0.93-1.07 and in stress study 0.93-1.09. The examinees older than 50 years had insignificantly lower perfusion reserve of these parameters compared with those younger than 50, LC (p=0.98), and RC (p=0.6). Conclusion This non-invasive scintigraphic method allows in individuals without peripheral artery disease to determine the range of normal values of muscle perfusion at rest and stress condition and to clinically implement them in evaluation of patients with peripheral artery disease for differentiating patients with normal from those with impaired lower limbs circulation.

Comparison of the biometric values obtained by two different A-mode ultrasound devices (Eye Cubed vs. PalmScan): A Transversal, descriptive, and comparative study

PubMed Central

2010-01-01

Background To assess the reliability of the measurements obtained with the PalmScan™, when compared with another standardized A-mode ultrasound device, and assess the consistency and correlation between the two methods. Methods Transversal, descriptive, and comparative study. We recorded the axial length (AL), anterior chamber depth (ACD) and lens thickness (LT) obtained with two A-mode ultrasounds (PalmScan™ A2000 and Eye Cubed™) using an immersion technique. We compared the measurements with a two-sample t-test. Agreement between the two devices was assessed with Bland-Altman plots and 95% limits of agreement. Results 70 eyes of 70 patients were enrolled in this study. The measurements with the Eye Cubed™ of AL and ACD were shorter than the measurements taken by the PalmScan™. The differences were not statistically significant regarding AL (p < 0.4) but significant regarding ACD (p < 0.001). The highest agreement between the two devices was obtained during LT measurement. The PalmScan™ measurements were shorter, but not statistically significantly (p < 0.2). Conclusions The values of AL and LT, obtained with both devices are not identical, but within the limits of agreement. The agreement is not affected by the magnitude of the ocular dimensions (but only between range of 20 mm to 27 mm of AL and 3.5 mm to 5.7 mm of LT). A correction of about 0.5 D could be considered if an intraocular lens is being calculated. However due to the large variability of the results, the authors recommend discretion in using this conversion factor, and to adjust the power of the intraocular lenses based upon the personal experience of the surgeon. PMID:20334670

Comparison of the biometric values obtained by two different A-mode ultrasound devices (Eye Cubed vs. PalmScan): a transversal, descriptive, and comparative study.

PubMed

Velez-Montoya, Raul; Shusterman, Eugene Mark; López-Miranda, Miriam Jessica; Mayorquin-Ruiz, Mariana; Salcedo-Villanueva, Guillermo; Quiroz-Mercado, Hugo; Morales-Cantón, Virgilio

2010-03-24

To assess the reliability of the measurements obtained with the PalmScan, when compared with another standardized A-mode ultrasound device, and assess the consistency and correlation between the two methods. Transversal, descriptive, and comparative study. We recorded the axial length (AL), anterior chamber depth (ACD) and lens thickness (LT) obtained with two A-mode ultrasounds (PalmScan A2000 and Eye Cubed) using an immersion technique. We compared the measurements with a two-sample t-test. Agreement between the two devices was assessed with Bland-Altman plots and 95% limits of agreement. 70 eyes of 70 patients were enrolled in this study. The measurements with the Eye Cubed of AL and ACD were shorter than the measurements taken by the PalmScan. The differences were not statistically significant regarding AL (p < 0.4) but significant regarding ACD (p < 0.001). The highest agreement between the two devices was obtained during LT measurement. The PalmScan measurements were shorter, but not statistically significantly (p < 0.2). The values of AL and LT, obtained with both devices are not identical, but within the limits of agreement. The agreement is not affected by the magnitude of the ocular dimensions (but only between range of 20 mm to 27 mm of AL and 3.5 mm to 5.7 mm of LT). A correction of about 0.5 D could be considered if an intraocular lens is being calculated. However due to the large variability of the results, the authors recommend discretion in using this conversion factor, and to adjust the power of the intraocular lenses based upon the personal experience of the surgeon.

Effect of storage conditions on the calorific value of municipal solid waste.

PubMed

Nzioka, Antony Mutua; Hwang, Hyeon-Uk; Kim, Myung-Gyun; Yan, Cao Zheng; Lee, Chang-Soo; Kim, Young-Ju

2017-08-01

Storage conditions are considered to be an important factor as far as waste material characteristics are concerned. This experimental investigation was conducted using municipal solid waste (MSW) with a high moisture content and varying composition of organic waste. The objective of this study was to understand the effect of storage conditions and temperature on the moisture content and calorific value of the waste. Samples were subjected to two different storage conditions and investigated at specified temperatures. The composition of sample materials investigated was varied for each storage condition and temperature respectively. Gross calorific value was determined experimentally while net calorific value was calculated using empirical formulas proposed by other researchers. Results showed minimal changes in moisture content as well as in gross and net calorific values when the samples were subjected to sealed storage conditions. Moisture content reduced due to the ventilation process and the rate of moisture removal increased with a rise in storage temperature. As expected, rate of moisture removal had a positive effect on gross and net calorific values. Net calorific values also increased at varying rates with a simultaneous decrease in moisture content. Experimental investigation showed the effectiveness of ventilation in improving the combustion characteristics of the waste.

Comparison with IRI-PLUS and IRI-2012-TEC values of GPS-TEC values

NASA Astrophysics Data System (ADS)

Atıcı, Ramazan; Saǧır, Selçuk

2016-07-01

This study presents a comparison with IRI-PLUS and IRI-2012 Total Electron Content (TEC) values of Total Electron Content (TEC) values obtained from Ankara station (39,7 N; 32,76 E) of Global Position System (GPS) of Turkey on equinox and solstice days of 2009 year. For all days, it is observed that GPS-TEC values are greater than IRI-2012-TEC values, while IRI-PLUS-TEC values are very close to GPS-TEC values. When GPS-TEC values for both equinoxes are compared, it is seen that TEC values on September equinox are greater than one on March equinox. However, it is observed that GPS-TEC values on June solstice are greater than one on December solstice. Also, the relationship between GPS-TEC values and geomagnetic indexes is investigated.

Tendon material properties vary and are interdependent among turkey hindlimb muscles.

PubMed

Matson, Andrew; Konow, Nicolai; Miller, Samuel; Konow, Pernille P; Roberts, Thomas J

2012-10-15

The material properties of a tendon affect its ability to store and return elastic energy, resist damage, provide mechanical feedback and amplify or attenuate muscle power. While the structural properties of a tendon are known to respond to a variety of stimuli, the extent to which material properties vary among individual muscles remains unclear. We studied the tendons of six different muscles in the hindlimb of Eastern wild turkeys to determine whether there was variation in elastic modulus, ultimate tensile strength and resilience. A hydraulic testing machine was used to measure tendon force during quasi-static lengthening, and a stress-strain curve was constructed. There was substantial variation in tendon material properties among different muscles. Average elastic modulus differed significantly between some tendons, and values for the six different tendons varied nearly twofold, from 829±140 to 1479±106 MPa. Tendons were stretched to failure, and the stress at failure, or ultimate tensile stress, was taken as a lower-limit estimate of tendon strength. Breaking tests for four of the tendons revealed significant variation in ultimate tensile stress, ranging from 66.83±14.34 to 112.37±9.39 MPa. Resilience, or the fraction of energy returned in cyclic length changes was generally high, and one of the four tendons tested was significantly different in resilience from the other tendons (range: 90.65±0.83 to 94.02±0.71%). An analysis of correlation between material properties revealed a positive relationship between ultimate tensile strength and elastic modulus (r(2)=0.79). Specifically, stiffer tendons were stronger, and we suggest that this correlation results from a constrained value of breaking strain, which did not vary significantly among tendons. This finding suggests an interdependence of material properties that may have a structural basis and may explain some adaptive responses observed in studies of tendon plasticity.

Adaptive Value Normalization in the Prefrontal Cortex Is Reduced by Memory Load.

PubMed

Holper, L; Van Brussel, L D; Schmidt, L; Schulthess, S; Burke, C J; Louie, K; Seifritz, E; Tobler, P N

2017-01-01

Adaptation facilitates neural representation of a wide range of diverse inputs, including reward values. Adaptive value coding typically relies on contextual information either obtained from the environment or retrieved from and maintained in memory. However, it is unknown whether having to retrieve and maintain context information modulates the brain's capacity for value adaptation. To address this issue, we measured hemodynamic responses of the prefrontal cortex (PFC) in two studies on risky decision-making. In each trial, healthy human subjects chose between a risky and a safe alternative; half of the participants had to remember the risky alternatives, whereas for the other half they were presented visually. The value of safe alternatives varied across trials. PFC responses adapted to contextual risk information, with steeper coding of safe alternative value in lower-risk contexts. Importantly, this adaptation depended on working memory load, such that response functions relating PFC activity to safe values were steeper with presented versus remembered risk. An independent second study replicated the findings of the first study and showed that similar slope reductions also arose when memory maintenance demands were increased with a secondary working memory task. Formal model comparison showed that a divisive normalization model fitted effects of both risk context and working memory demands on PFC activity better than alternative models of value adaptation, and revealed that reduced suppression of background activity was the critical parameter impairing normalization with increased memory maintenance demand. Our findings suggest that mnemonic processes can constrain normalization of neural value representations.

Adaptive Value Normalization in the Prefrontal Cortex Is Reduced by Memory Load

PubMed Central

Burke, C. J.; Seifritz, E.; Tobler, P. N.

2017-01-01

Abstract Adaptation facilitates neural representation of a wide range of diverse inputs, including reward values. Adaptive value coding typically relies on contextual information either obtained from the environment or retrieved from and maintained in memory. However, it is unknown whether having to retrieve and maintain context information modulates the brain’s capacity for value adaptation. To address this issue, we measured hemodynamic responses of the prefrontal cortex (PFC) in two studies on risky decision-making. In each trial, healthy human subjects chose between a risky and a safe alternative; half of the participants had to remember the risky alternatives, whereas for the other half they were presented visually. The value of safe alternatives varied across trials. PFC responses adapted to contextual risk information, with steeper coding of safe alternative value in lower-risk contexts. Importantly, this adaptation depended on working memory load, such that response functions relating PFC activity to safe values were steeper with presented versus remembered risk. An independent second study replicated the findings of the first study and showed that similar slope reductions also arose when memory maintenance demands were increased with a secondary working memory task. Formal model comparison showed that a divisive normalization model fitted effects of both risk context and working memory demands on PFC activity better than alternative models of value adaptation, and revealed that reduced suppression of background activity was the critical parameter impairing normalization with increased memory maintenance demand. Our findings suggest that mnemonic processes can constrain normalization of neural value representations. PMID:28462394

Robust state estimation for uncertain fuzzy bidirectional associative memory networks with time-varying delays

NASA Astrophysics Data System (ADS)

Vadivel, P.; Sakthivel, R.; Mathiyalagan, K.; Arunkumar, A.

2013-09-01

This paper addresses the issue of robust state estimation for a class of fuzzy bidirectional associative memory (BAM) neural networks with time-varying delays and parameter uncertainties. By constructing the Lyapunov-Krasovskii functional, which contains the triple-integral term and using the free-weighting matrix technique, a set of sufficient conditions are derived in terms of linear matrix inequalities (LMIs) to estimate the neuron states through available output measurements such that the dynamics of the estimation error system is robustly asymptotically stable. In particular, we consider a generalized activation function in which the traditional assumptions on the boundedness, monotony and differentiability of the activation functions are removed. More precisely, the design of the state estimator for such BAM neural networks can be obtained by solving some LMIs, which are dependent on the size of the time derivative of the time-varying delays. Finally, a numerical example with simulation result is given to illustrate the obtained theoretical results.

Varying-energy CT imaging method based on EM-TV

NASA Astrophysics Data System (ADS)

Chen, Ping; Han, Yan

2016-11-01

For complicated structural components with wide x-ray attenuation ranges, conventional fixed-energy computed tomography (CT) imaging cannot obtain all the structural information. This limitation results in a shortage of CT information because the effective thickness of the components along the direction of x-ray penetration exceeds the limit of the dynamic range of the x-ray imaging system. To address this problem, a varying-energy x-ray CT imaging method is proposed. In this new method, the tube voltage is adjusted several times with the fixed lesser interval. Next, the fusion of grey consistency and logarithm demodulation are applied to obtain full and lower noise projection with a high dynamic range (HDR). In addition, for the noise suppression problem of the analytical method, EM-TV (expectation maximization-total Jvariation) iteration reconstruction is used. In the process of iteration, the reconstruction result obtained at one x-ray energy is used as the initial condition of the next iteration. An accompanying experiment demonstrates that this EM-TV reconstruction can also extend the dynamic range of x-ray imaging systems and provide a higher reconstruction quality relative to the fusion reconstruction method.

Universal values of Canadian astronauts

NASA Astrophysics Data System (ADS)

Brcic, Jelena; Della-Rossa, Irina

2012-11-01

Values are desirable, trans-situational goals, varying in importance, that guide behavior. Research has demonstrated that universal values may alter in importance as a result of major life events. The present study examines the effect of spaceflight and the demands of astronauts' job position as life circumstances that affect value priorities. We employed thematic content analysis for references to Schwartz's well-established value markers in narratives (media interviews, journals, and pre-flight interviews) of seven Canadian astronauts and compared the results to the values of National Aeronautics and Space Administration (NASA) and Russian Space Agency (RKA) astronauts. Space flight did alter the level of importance of Canadian astronauts' values. We found a U-shaped pattern for the values of Achievement and Tradition before, during, and after flight, and a linear decrease in the value of Stimulation. The most frequently mentioned values were Achievement, Universalism, Security, and Self-Direction. Achievement and Self Direction are also within the top 4 values of all other astronauts; however, Universalism was significantly higher among the Canadian astronauts. Within the value hierarchy of Canadian astronauts, Security was the third most frequently mentioned value, while it is in seventh place for all other astronauts. Interestingly, the most often mentioned value marker (sub-category) in this category was Patriotism. The findings have important implications in understanding multi-national crew relations during training, flight, and reintegration into society.

Proanthocyanidin profile and ORAC values of Manitoba berries, chokecherries, and seabuckthorn.

PubMed

Hosseinian, Farah S; Li, Wende; Hydamaka, Arnie W; Tsopmo, Apollinaire; Lowry, Lynda; Friel, James; Beta, Trust

2007-08-22

Six Manitoba fruits were analyzed for their phytochemical content and antioxidant activity in order to increase their production and marketability. The major proanthocyanidins (flavanols) present in whole fruit, juice, and pulp of strawberry, Saskatoon berry, raspberry, wild blueberry, chokecherry, and seabuckthorn were measured. The extraction and purification were facilitated using flash column chromatography, while separation and identification were accomplished by using HPLC and LC-MS techniques. The total proanthocyanidin contents varied from 275.55 to 504.77 mg/100 g in the whole fruit samples. Raspberry contained the highest content, and seabuckthorn showed the lowest content of total flavanols. The highest concentration of proanthocyanidin in juice was found in Saskatoon berry (1363.34 mg/100 mL) and the lowest value in strawberry (622.60 mg/100 mL). HPLC and LC-MS results indicated that epicatechin was the most abundant flavanol followed by B2 in the berry samples, while no catechin or B1 was detected in these fruits. A series of oligomers and polymers were detected in all samples. The recovery percentage was obtained from the ratio of the unspiked samples to the area of spiked samples. Monomers, dimers, oligomers, and polymers gave recovery ranges of 83-99%. The lipophilic and hydrophilic antioxidant capacities of whole fruit, juice, and pulp extracts were measured by the oxygen radical absorbance capacity (ORAC) procedure. In whole fruits, the ORAC values varied from 135 to 479 mg/100 g TE in the MeOH fraction. The corresponding ORAC values varied from 115.30 to 733.15 mg/100 g for the acetone fraction. In juice, all berries showed the same antioxidant capacity (P > 0.05) (133.0-312.0 mg/100 g) in the MeOH fraction, with the exception of raspberry (603.0 mg/100 g). Overall, MeOH fractions mainly contained monomers and dimers with smaller amounts of oligomers and polymers when compared to the acetone fractions. Acetone fractions mainly contained polymers

Organic particulate matter formation at varying relative humidity using surrogate secondary and primary organic compounds with activity corrections in the condensed phase obtained using a method based on the Wilson equation

NASA Astrophysics Data System (ADS)

Chang, E. I.; Pankow, J. F.

2010-06-01

Secondary organic aerosol (SOA) formation in the atmosphere is currently often modeled using a multiple lumped "two-product" (N·2p) approach. The N·2p approach neglects: 1) variation of activity coefficient (ζi) values and mean molecular weight MW in the particulate matter (PM) phase; 2) water uptake into the PM; and 3) the possibility of phase separation in the PM. This study considers these effects by adopting an (N·2p)ζpMW,ζ approach (θ is a phase index). Specific chemical structures are assigned to 25 lumped SOA compounds and to 15 representative primary organic aerosol (POA) compounds to allow calculation of ζi and MW values. The SOA structure assignments are based on chamber-derived 2p gas/particle partition coefficient values coupled with known effects of structure on vapor pressure pL,io (atm). To facilitate adoption of the (N·2p)ζpMW,θ approach in large-scale models, this study also develops CP-Wilson.1 (Chang-Pankow-Wilson.1), a group-contribution ζi-prediction method that is more computationally economical than the UNIFAC model of Fredenslund et al. (1975). Group parameter values required by CP-Wilson.1 are obtained by fitting ζi values to predictions from UNIFAC. The (N·2p)ζpMW,θ approach is applied (using CP-Wilson.1) to several real α-pinene/O3 chamber cases for high reacted hydrocarbon levels (ΔHC≈400 to 1000 μg m-3) when relative humidity (RH) ≍50%. Good agreement between the chamber and predicted results is obtained using both the (N·2p)ζpMW,θ and N·2p approaches, indicating relatively small water effects under these conditions. However, for a hypothetical α-pinene/O3 case at ΔHC=30 μg m-3 and

Inappropriate fiddling with statistical analyses to obtain a desirable p-value: tests to detect its presence in published literature.

PubMed

Gadbury, Gary L; Allison, David B

2012-01-01

Much has been written regarding p-values below certain thresholds (most notably 0.05) denoting statistical significance and the tendency of such p-values to be more readily publishable in peer-reviewed journals. Intuition suggests that there may be a tendency to manipulate statistical analyses to push a "near significant p-value" to a level that is considered significant. This article presents a method for detecting the presence of such manipulation (herein called "fiddling") in a distribution of p-values from independent studies. Simulations are used to illustrate the properties of the method. The results suggest that the method has low type I error and that power approaches acceptable levels as the number of p-values being studied approaches 1000.

How to Assess the Value of Medicines?

PubMed Central

Simoens, Steven

2010-01-01

This study aims to discuss approaches to assessing the value of medicines. Economic evaluation assesses value by means of the incremental cost-effectiveness ratio (ICER). Health is maximized by selecting medicines with increasing ICERs until the budget is exhausted. The budget size determines the value of the threshold ICER and vice versa. Alternatively, the threshold value can be inferred from pricing/reimbursement decisions, although such values vary between countries. Threshold values derived from the value-of-life literature depend on the technique used. The World Health Organization has proposed a threshold value tied to the national GDP. As decision makers may wish to consider multiple criteria, variable threshold values and weighted ICERs have been suggested. Other approaches (i.e., replacement approach, program budgeting and marginal analysis) have focused on improving resource allocation, rather than maximizing health subject to a budget constraint. Alternatively, the generalized optimization framework and multi-criteria decision analysis make it possible to consider other criteria in addition to value. PMID:21607066

How to assess the value of medicines?

PubMed

Simoens, Steven

2010-01-01

This study aims to discuss approaches to assessing the value of medicines. Economic evaluation assesses value by means of the incremental cost-effectiveness ratio (ICER). Health is maximized by selecting medicines with increasing ICERs until the budget is exhausted. The budget size determines the value of the threshold ICER and vice versa. Alternatively, the threshold value can be inferred from pricing/reimbursement decisions, although such values vary between countries. Threshold values derived from the value-of-life literature depend on the technique used. The World Health Organization has proposed a threshold value tied to the national GDP. As decision makers may wish to consider multiple criteria, variable threshold values and weighted ICERs have been suggested. Other approaches (i.e., replacement approach, program budgeting and marginal analysis) have focused on improving resource allocation, rather than maximizing health subject to a budget constraint. Alternatively, the generalized optimization framework and multi-criteria decision analysis make it possible to consider other criteria in addition to value.

Process-based modelling of the nutritive value of forages: a review

USDA-ARS?s Scientific Manuscript database

Modelling sward nutritional value (NV) is of particular importance to understand the interactions between grasslands, livestock production, environment and climate-related impacts. Variables describing nutritive value vary significantly between ruminant production systems, but two types are commonly...

Obtaining information by dynamic (effortful) touching

PubMed Central

Turvey, M. T.; Carello, Claudia

2011-01-01

Dynamic touching is effortful touching. It entails deformation of muscles and fascia and activation of the embedded mechanoreceptors, as when an object is supported and moved by the body. It is realized as exploratory activities that can vary widely in spatial and temporal extents (a momentary heft, an extended walk). Research has revealed the potential of dynamic touching for obtaining non-visual information about the body (e.g. limb orientation), attachments to the body (e.g. an object's height and width) and the relation of the body both to attachments (e.g. hand's location on a grasped object) and surrounding surfaces (e.g. places and their distances). Invariants over the exploratory activity (e.g. moments of a wielded object's mass distribution) seem to ground this ‘information about’. The conception of a haptic medium as a nested tensegrity structure has been proposed to express the obtained information realized by myofascia deformation, by its invariants and transformations. The tensegrity proposal rationalizes the relative indifference of dynamic touch to the site of mechanical contact (hand, foot, torso or probe) and the overtness of exploratory activity. It also provides a framework for dynamic touching's fractal nature, and the finding that its degree of fractality may matter to its accomplishments. PMID:21969694

Attention! Can choices for low value food over high value food be trained?

PubMed

Zoltak, Michael J; Veling, Harm; Chen, Zhang; Holland, Rob W

2018-05-01

People choose high value food items over low value food items, because food choices are guided by the comparison of values placed upon choice alternatives. This value comparison process is also influenced by the amount of attention people allocate to different items. Recent research shows that choices for food items can be increased by training attention toward these items, with a paradigm named cued-approach training (CAT). However, previous work till now has only examined the influence of CAT on choices between two equally valued items. It has remained unclear whether CAT can increase choices for low value items when people choose between a low and high value food item. To address this question in the current study participants were cued to make rapid responses in CAT to certain low and high value items. Next, they made binary choices between low and high value items, where we systematically varied whether the low and high value items were cued or uncued. In two experiments, we found that participants overall preferred high over low value food items for real consumption. More important, their choices for low value items increased when only the low value item had been cued in CAT compared to when both low and high value items had not been cued. Exploratory analyses revealed that this effect was more pronounced for participants with a relatively small value difference between low and high value items. The present research thus suggests that CAT may be used to boost the choice and consumption of low value items via enhanced attention toward these items, as long as the value difference is not too large. Implications for facilitating choices for healthy food are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

A simple cosmology with a varying fine structure constant.

PubMed

Sandvik, Håvard Bunes; Barrow, John D; Magueijo, João

2002-01-21

We investigate the cosmological consequences of a theory in which the electric charge e can vary. In this theory the fine structure "constant," alpha, remains almost constant in the radiation era, undergoes a small increase in the matter era, but approaches a constant value when the universe starts accelerating because of a positive cosmological constant. This model satisfies geonuclear, nucleosynthesis, and cosmic microwave background constraints on time variation in alpha, while fitting the observed accelerating Universe and evidence for small alpha variations in quasar spectra. It also places specific restrictions on the nature of the dark matter. Further tests, involving stellar spectra and Eötvös experiments, are proposed.

Porous materials based on foaming solutions obtained from industrial waste

NASA Astrophysics Data System (ADS)

Starostina, I. V.; Antipova, A. N.; Ovcharova, I. V.; Starostina, Yu L.

2018-03-01

This study analyzes foam concrete production efficiency. Research has shown the possibility of using a newly-designed protein-based foaming agent to produce porous materials using gypsum and cement binders. The protein foaming agent is obtained by alkaline hydrolysis of a raw mixture consisting of industrial waste in an electromagnetic field. The mixture consists of spent biomass of the Aspergillus niger fungus and dust from burning furnaces used in cement production. Varying the content of the foaming agent allows obtaining gypsum binder-based foam concretes with the density of 200-500 kg/m3 and compressive strength of 0.1-1.0 MPa, which can be used for thermal and sound insulation of building interiors. Cement binders were used to obtain structural and thermal insulation materials with the density of 300-950 kg/m3 and compressive strength of 0.9-9.0 MPa. The maximum operating temperature of cement-based foam concretes is 500°C because it provides the shrinkage of less than 2%.

Statistical Analysis of the Ionosphere based on Singular Value Decomposition

NASA Astrophysics Data System (ADS)

Demir, Uygar; Arikan, Feza; Necat Deviren, M.; Toker, Cenk

2016-07-01

Ionosphere is made up of a spatio-temporally varying trend structure and secondary variations due to solar, geomagnetic, gravitational and seismic activities. Hence, it is important to monitor the ionosphere and acquire up-to-date information about its state in order both to better understand the physical phenomena that cause the variability and also to predict the effect of the ionosphere on HF and satellite communications, and satellite-based positioning systems. To charaterise the behaviour of the ionosphere, we propose to apply Singular Value Decomposition (SVD) to Total Electron Content (TEC) maps obtained from the TNPGN-Active (Turkish National Permanent GPS Network) CORS network. TNPGN-Active network consists of 146 GNSS receivers spread over Turkey. IONOLAB-TEC values estimated from each station are spatio-temporally interpolated using a Universal Kriging based algorithm with linear trend, namely IONOLAB-MAP, with very high spatial resolution. It is observed that the dominant singular value of TEC maps is an indicator of the trend structure of the ionosphere. The diurnal, seasonal and annual variability of the most dominant value is the representation of solar effect on ionosphere in midlatitude range. Secondary and smaller singular values are indicators of secondary variation which can have significance especially during geomagnetic storms or seismic disturbances. The dominant singular values are related to the physical basis vectors where ionosphere can be fully reconstructed using these vectors. Therefore, the proposed method can be used both for the monitoring of the current state of a region and also for the prediction and tracking of future states of ionosphere using singular values and singular basis vectors. This study is supported by by TUBITAK 115E915 and Joint TUBITAK 114E092 and AS CR14/001 projects.

The transition to value-based care.

PubMed

Ray, Jordan C; Kusumoto, Fred

2016-10-01

Delivery of medical care is evolving rapidly worldwide. Over the past several years in the USA, there has been a rapid shift in reimbursement from a simple fee-for-service model to more complex models that attempt to link payment to quality and value. Change in any large system can be difficult, but with medicine, the transition to a value-based system has been particularly hard to implement because both quality and cost are difficult to quantify. Professional societies and other medical groups are developing different programs in an attempt to define high value care. However, applying a national standard of value for any treatment is challenging, since value varies from person to person, and the individual benefit must remain the central tenet for delivering best patient-centered medical care. Regardless of the specific operational features of the rapidly changing healthcare environment, physicians must first and foremost always remain patient advocates.

Neural coding of time-varying interaural time differences and time-varying amplitude in the inferior colliculus

PubMed Central

2017-01-01

Binaural cues occurring in natural environments are frequently time varying, either from the motion of a sound source or through interactions between the cues produced by multiple sources. Yet, a broad understanding of how the auditory system processes dynamic binaural cues is still lacking. In the current study, we directly compared neural responses in the inferior colliculus (IC) of unanesthetized rabbits to broadband noise with time-varying interaural time differences (ITD) with responses to noise with sinusoidal amplitude modulation (SAM) over a wide range of modulation frequencies. On the basis of prior research, we hypothesized that the IC, one of the first stages to exhibit tuning of firing rate to modulation frequency, might use a common mechanism to encode time-varying information in general. Instead, we found weaker temporal coding for dynamic ITD compared with amplitude modulation and stronger effects of adaptation for amplitude modulation. The differences in temporal coding of dynamic ITD compared with SAM at the single-neuron level could be a neural correlate of “binaural sluggishness,” the inability to perceive fluctuations in time-varying binaural cues at high modulation frequencies, for which a physiological explanation has so far remained elusive. At ITD-variation frequencies of 64 Hz and above, where a temporal code was less effective, noise with a dynamic ITD could still be distinguished from noise with a constant ITD through differences in average firing rate in many neurons, suggesting a frequency-dependent tradeoff between rate and temporal coding of time-varying binaural information. NEW & NOTEWORTHY Humans use time-varying binaural cues to parse auditory scenes comprising multiple sound sources and reverberation. However, the neural mechanisms for doing so are poorly understood. Our results demonstrate a potential neural correlate for the reduced detectability of fluctuations in time-varying binaural information at high speeds, as occurs

Absorption Ångström exponents of aerosols and light absorbing carbon (LAC) obtained from in situ data in Covilhã, central Portugal.

PubMed

Mogo, S; Cachorro, V E; de Frutos, A; Rodrigues, A

2012-12-01

A field campaign was conducted from October 2009 to July 2010 at Covilhã, a small town located in the region of Beira Interior (Portugal) in the interior of the Iberian Peninsula. The ambient light-absorption coefficient, σ(a) (522 nm), obtained from a Particle Soot Absorption Photometer (PSAP), presented a daily mean value of 12.1 Mm⁻¹ (StD = 7.3 Mm⁻¹). The wavelength dependence of aerosol light absorption is investigated through the Ångström parameter, α(a). The α(a) values for the pair of wavelengths 470-660 nm ranged from 0.86 to 1.47 during the period of measurements. The PSAP data were used to infer the mass of light absorbing carbon (LAC) and the daily mean varied from 0.1 to 6.8 μg m⁻³. A detailed study of special events with different aerosol characteristics is carried out and, to support data interpretation, air masses trajectory analysis is performed.

Revisiting crash spatial heterogeneity: A Bayesian spatially varying coefficients approach.

PubMed

Xu, Pengpeng; Huang, Helai; Dong, Ni; Wong, S C

2017-01-01

This study was performed to investigate the spatially varying relationships between crash frequency and related risk factors. A Bayesian spatially varying coefficients model was elaborately introduced as a methodological alternative to simultaneously account for the unstructured and spatially structured heterogeneity of the regression coefficients in predicting crash frequencies. The proposed method was appealing in that the parameters were modeled via a conditional autoregressive prior distribution, which involved a single set of random effects and a spatial correlation parameter with extreme values corresponding to pure unstructured or pure spatially correlated random effects. A case study using a three-year crash dataset from the Hillsborough County, Florida, was conducted to illustrate the proposed model. Empirical analysis confirmed the presence of both unstructured and spatially correlated variations in the effects of contributory factors on severe crash occurrences. The findings also suggested that ignoring spatially structured heterogeneity may result in biased parameter estimates and incorrect inferences, while assuming the regression coefficients to be spatially clustered only is probably subject to the issue of over-smoothness. Copyright © 2016 Elsevier Ltd. All rights reserved.

Partitioned key-value store with atomic memory operations

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

Bent, John M.; Faibish, Sorin; Grider, Gary

A partitioned key-value store is provided that supports atomic memory operations. A server performs a memory operation in a partitioned key-value store by receiving a request from an application for at least one atomic memory operation, the atomic memory operation comprising a memory address identifier; and, in response to the atomic memory operation, performing one or more of (i) reading a client-side memory location identified by the memory address identifier and storing one or more key-value pairs from the client-side memory location in a local key-value store of the server; and (ii) obtaining one or more key-value pairs from themore » local key-value store of the server and writing the obtained one or more key-value pairs into the client-side memory location identified by the memory address identifier. The server can perform functions obtained from a client-side memory location and return a result to the client using one or more of the atomic memory operations.« less

Clinical utility of apparent diffusion coefficient values obtained using high b-value when diagnosing prostate cancer using 3 tesla MRI: comparison between ultra-high b-value (2000 s/mm²) and standard high b-value (1000 s/mm²).

PubMed

Kitajima, Kazuhiro; Takahashi, Satoru; Ueno, Yoshiko; Yoshikawa, Takeshi; Ohno, Yoshiharu; Obara, Makoto; Miyake, Hideaki; Fujisawa, Masato; Sugimura, Kazuro

2012-07-01

To determine whether the apparent diffusion coefficient (ADC) obtained using b = 2000 s/mm(2) upon 3 Tesla (T) diffusion-weighted MRI is superior to b = 1000 s/mm(2) for discriminating malignant from normal prostate tissue and predicting the aggressiveness of prostate cancer, using histopathological findings of radical prostatectomy as a reference. Eighty prostate cancer patients underwent preoperative 3T MRI including diffusion weighted imaging with b-values of 0, 1000, and 2000 s/mm(2) . ADCs were measured for malignant lesions and normal sites on three sets of ADC maps calculated with monoexponential fitting between b = 0 and 1000, 0 and 2000, and 1000 and 2000, respectively. The relationship between the ADC and Gleason score was evaluated. The areas under the ROC curves for b = 0,1000, b = 0,2000, and b = 1000,2000 were 0.896, 0.937, and 0.857, respectively, in the peripheral zone (PZ) and 0.877, 0.889, and 0.731, respectively, in the transition zone (TZ). The difference between b = 0,1000 and b = 0,2000 was significant in PZ (P = 0.033), but not in TZ (P = 0.84). Weak but significant negative correlations were identified between ADCs and Gleason score in both PZ and TZ cancer at b = 0,1000 and b = 0,2000 (r = -0.323 to -0.341). For 3T MRI, ADCs using b = 0,2000 are more accurate than b = 0,1000 for diagnosing PZ cancer, and as accurate for TZ cancer. Copyright © 2012 Wiley Periodicals, Inc.

Inappropriate Fiddling with Statistical Analyses to Obtain a Desirable P-value: Tests to Detect its Presence in Published Literature

PubMed Central

Gadbury, Gary L.; Allison, David B.

2012-01-01

Much has been written regarding p-values below certain thresholds (most notably 0.05) denoting statistical significance and the tendency of such p-values to be more readily publishable in peer-reviewed journals. Intuition suggests that there may be a tendency to manipulate statistical analyses to push a “near significant p-value” to a level that is considered significant. This article presents a method for detecting the presence of such manipulation (herein called “fiddling”) in a distribution of p-values from independent studies. Simulations are used to illustrate the properties of the method. The results suggest that the method has low type I error and that power approaches acceptable levels as the number of p-values being studied approaches 1000. PMID:23056287

Use of multivariate statistics to identify unreliable data obtained using CASA.

PubMed

Martínez, Luis Becerril; Crispín, Rubén Huerta; Mendoza, Maximino Méndez; Gallegos, Oswaldo Hernández; Martínez, Andrés Aragón

2013-06-01

In order to identify unreliable data in a dataset of motility parameters obtained from a pilot study acquired by a veterinarian with experience in boar semen handling, but without experience in the operation of a computer assisted sperm analysis (CASA) system, a multivariate graphical and statistical analysis was performed. Sixteen boar semen samples were aliquoted then incubated with varying concentrations of progesterone from 0 to 3.33 µg/ml and analyzed in a CASA system. After standardization of the data, Chernoff faces were pictured for each measurement, and a principal component analysis (PCA) was used to reduce the dimensionality and pre-process the data before hierarchical clustering. The first twelve individual measurements showed abnormal features when Chernoff faces were drawn. PCA revealed that principal components 1 and 2 explained 63.08% of the variance in the dataset. Values of principal components for each individual measurement of semen samples were mapped to identify differences among treatment or among boars. Twelve individual measurements presented low values of principal component 1. Confidence ellipses on the map of principal components showed no statistically significant effects for treatment or boar. Hierarchical clustering realized on two first principal components produced three clusters. Cluster 1 contained evaluations of the two first samples in each treatment, each one of a different boar. With the exception of one individual measurement, all other measurements in cluster 1 were the same as observed in abnormal Chernoff faces. Unreliable data in cluster 1 are probably related to the operator inexperience with a CASA system. These findings could be used to objectively evaluate the skill level of an operator of a CASA system. This may be particularly useful in the quality control of semen analysis using CASA systems.

Methods of obtaining a uniform volume concentration of implanted ions

NASA Astrophysics Data System (ADS)

Reutov, V. F.

1998-05-01

Three simple practical methods of irradiation with high energy particles (>5 MeV/n), providing the conditions of obtaining a uniform volume concentration of the implanted ions in the massive samples are described in the present paper. Realization of the condition of two-sided irradiation of a plane sample during its rotation in the flux of the projectiles is the basis of the first method. The use of free air as a filter with varying absorbent ability due to the movement of the irradiated sample along ion beam brought to the atmosphere is at the basis of the second method of uniform ion alloying. The third method of obtaining a uniform volume concentration of the implanted ions in a massive sample consists of sample irradiation through the absorbent filter in the shape of a foil curved according to the parabolic law moving along its surface. The first method is the most effective for obtaining a great number of the samples, for mechanical tests, for example, the second one - for irradiation in different gaseous media, the third one - for obtaining high concentration of the implanted ions under controlled (regulated) thermal and deformation conditions.

Wave scattering by an axisymmetric ice floe of varying thickness

NASA Astrophysics Data System (ADS)

Bennetts, Luke G.; Biggs, Nicholas R. T.; Porter, David

2009-04-01

The problem of water wave scattering by a circular ice floe, floating in fluid of finite depth, is formulated and solved numerically. Unlike previous investigations of such situations, here we allow the thickness of the floe (and the fluid depth) to vary axisymmetrically and also incorporate a realistic non-zero draught. A numerical approximation to the solution of this problem is obtained to an arbitrary degree of accuracy by combining a Rayleigh-Ritz approximation of the vertical motion with an appropriate variational principle. This numerical solution procedure builds upon the work of Bennets et al. (2007, J. Fluid Mech., 579, 413-443). As part of the numerical formulation, we utilize a Fourier cosine expansion of the azimuthal motion, resulting in a system of ordinary differential equations to solve in the radial coordinate for each azimuthal mode. The displayed results concentrate on the response of the floe rather than the scattered wave field and show that the effects of introducing the new features of varying floe thickness and a realistic draught are significant.

Cold fission description with constant and varying mass asymmetries

NASA Astrophysics Data System (ADS)

Duarte, S. B.; Rodríguez, O.; Tavares, O. A. P.; Gonçalves, M.; García, F.; Guzmán, F.

1998-05-01

Different descriptions for varying the mass asymmetry in the fragmentation process are used to calculate the cold fission barrier penetrability. The relevance of the appropriate choice for both the description of the prescission phase and inertia coefficient to unify alpha decay, cluster radioactivity, and spontaneous cold fission processes in the same theoretical framework is explicitly shown. We calculate the half-life of all possible partition modes of nuclei of A>200 following the most recent Mass Table by Audi and Wapstra. It is shown that if one uses the description in which the mass asymmetry is maintained constant during the fragmentation process, the experimental half-life values and mass yield of 234U cold fission are satisfactorily reproduced.

HDPE/HA composites obtained in solution: Effect of the gamma radiation

NASA Astrophysics Data System (ADS)

Carmen, Albano; Arquímedes, Karam; Rosestela, Perera; Gema, González; Nohemy, Domínguez; Jeanette, González; Yanixia, Sánchez

2006-06-01

Radiation is employed to sterilize composite materials used in the biomedical field. Due to the changes induced by radiation onto polymeric materials, it is important to study variations in their melt flow index (MFI), as well as in their mechanical and thermal properties. In this work, those previous parameters were determined in composites obtained via solution of a high-density polyethylene (HDPE) in decalin, with different amounts of hydroxyapatite (HA), varying from 10 to 30 parts per hundred, after being exposed to gamma radiation at absorbed doses between 25 and 100 kGy. After the irradiation, the MFI of HDPE dissolved in decalin and precipitated afterwards and without filler increased from 6 to 24 g/10 min at the highest absorbed doses. This behavior was also observed in composites with 10 pph of HA, being the increase less pronounced, specifically in the range between 50 and 100 kGy. Composites with 20 and 30 pph of HA showed a maximum MFI value at 50 kGy, which decreased at higher doses. This implies that the filler begin to exert an influence because it does not melt at the test temperature and consequently, it does not flow. It was observed that Young's modulus increased with HA addition due to rigidity of the ceramic filler. Radiation did not significantly affect this tensile property. On the other hand, the tensile strength did not show significant variations at the different doses but the filler content did affect this property improving it. Finally, elongation at break showed a drastic decrease with filler addition. When the thermal behavior was studied it was noticed that crystallization and melting temperatures remained unchanged. Instead, crystallinity degree slightly increased in the composites, and a little decrease was obtained when they were irradiated.

The value of post-extracted algae residue

DOE PAGES

Bryant, Henry; Gogichaishvili, Ilia; Anderson, David; ...

2012-07-26

This paper develops a hedonic pricing model for post-extracted algae residue (PEAR), which can be used for assessing the economic feasibility of an algal production enterprise. Prices and nutritional characteristics of commonly employed livestock feed ingredients are used to estimate the value of PEAR based on its composition. We find that PEAR would have a value lower than that of soybean meal in recent years. The value of PEAR will vary substantially based on its characteristics. PEAR could have generated algal fuel co-product credits that in recent years would have ranged between $0.95 and $2.43 per gallon of fuel produced.

Hot Ductility Behavior of Boron Containing Microalloyed Steels with Varying Manganese Contents

NASA Astrophysics Data System (ADS)

Brune, Tobias; Senk, Dieter; Walpot, Raphael; Steenken, Bernhard

2015-02-01

The hot ductility is measured for six different steel grades with different microalloying elements and with varying manganese contents using the hot tensile test machine with melting/solidification unit at the Department of Ferrous Metallurgy RWTH Aachen University. To identify the influence of manganese on hot ductility, tests are performed with varying the manganese content from 0.7 to 18.2 wt pct, a high manganese steel. Additionally, the effect of different cooling and strain rates is analyzed by changing the particular rate for selected samples in the minima. To investigate and detect the cause of cracking during testing, the fracture surfaces in the ductility minima are considered with scanning electron microscope-energy dispersive X-ray spectroscopy. Thermodynamic modeling is conducted on basis of the commercial software ThermoCalc©. A sharp decrease of the hot ductility is recognizable at 1398 K (1125 °C), at only 0.7 wt pct manganese because of the low manganese to sulfur ratio. The grades with a Mn content up to 1.9 wt pct show a good ductility with minimal ductility loss. In comparison, the steel grade with 18.2 wt pct has a poor hot ductility. Because of the formation of complex precipitates, where several alloying elements are involved, the influence of boron on hot ductility is not fully clarified. By increasing the cooling rate, the reduction of area values are shifted to smaller values. For high test temperatures, these measured values are decreased for lower strain rates. Thereby, an early drop of the ductility is noticeable for the high temperatures around 1373 K (1100 °C).

A varying coefficient model to measure the effectiveness of mass media anti-smoking campaigns in generating calls to a Quitline.

PubMed

Bui, Quang M; Huggins, Richard M; Hwang, Wen-Han; White, Victoria; Erbas, Bircan

2010-01-01

Anti-smoking advertisements are an effective population-based smoking reduction strategy. The Quitline telephone service provides a first point of contact for adults considering quitting. Because of data complexity, the relationship between anti-smoking advertising placement, intensity, and time trends in total call volume is poorly understood. In this study we use a recently developed semi-varying coefficient model to elucidate this relationship. Semi-varying coefficient models comprise parametric and nonparametric components. The model is fitted to the daily number of calls to Quitline in Victoria, Australia to estimate a nonparametric long-term trend and parametric terms for day-of-the-week effects and to clarify the relationship with target audience rating points (TARPs) for the Quit and nicotine replacement advertising campaigns. The number of calls to Quitline increased with the TARP value of both the Quit and other smoking cessation advertisement; the TARP values associated with the Quit program were almost twice as effective. The varying coefficient term was statistically significant for peak periods with little or no advertising. Semi-varying coefficient models are useful for modeling public health data when there is little or no information on other factors related to the at-risk population. These models are well suited to modeling call volume to Quitline, because the varying coefficient allowed the underlying time trend to depend on fixed covariates that also vary with time, thereby explaining more of the variation in the call model.

A Varying Coefficient Model to Measure the Effectiveness of Mass Media Anti-Smoking Campaigns in Generating Calls to a Quitline

PubMed Central

Bui, Quang M.; Huggins, Richard M.; Hwang, Wen-Han; White, Victoria; Erbas, Bircan

2010-01-01

Background Anti-smoking advertisements are an effective population-based smoking reduction strategy. The Quitline telephone service provides a first point of contact for adults considering quitting. Because of data complexity, the relationship between anti-smoking advertising placement, intensity, and time trends in total call volume is poorly understood. In this study we use a recently developed semi-varying coefficient model to elucidate this relationship. Methods Semi-varying coefficient models comprise parametric and nonparametric components. The model is fitted to the daily number of calls to Quitline in Victoria, Australia to estimate a nonparametric long-term trend and parametric terms for day-of-the-week effects and to clarify the relationship with target audience rating points (TARPs) for the Quit and nicotine replacement advertising campaigns. Results The number of calls to Quitline increased with the TARP value of both the Quit and other smoking cessation advertisement; the TARP values associated with the Quit program were almost twice as effective. The varying coefficient term was statistically significant for peak periods with little or no advertising. Conclusions Semi-varying coefficient models are useful for modeling public health data when there is little or no information on other factors related to the at-risk population. These models are well suited to modeling call volume to Quitline, because the varying coefficient allowed the underlying time trend to depend on fixed covariates that also vary with time, thereby explaining more of the variation in the call model. PMID:20827036

Bending of solitons in weak and slowly varying inhomogeneous plasma

NASA Astrophysics Data System (ADS)

Mukherjee, Abhik; Janaki, M. S.; Kundu, Anjan

2015-12-01

The bending of solitons in two dimensional plane is presented in the presence of weak and slowly varying inhomogeneous ion density for the propagation of ion acoustic soliton in unmagnetized cold plasma with isothermal electrons. Using reductive perturbation technique, a modified Kadomtsev-Petviashvili equation is obtained with a chosen unperturbed ion density profile. The exact solution of the equation shows that the phase of the solitary wave gets modified by a function related to the unperturbed inhomogeneous ion density causing the soliton to bend in the two dimensional plane, while the amplitude of the soliton remains constant.

Bending of solitons in weak and slowly varying inhomogeneous plasma

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

Mukherjee, Abhik, E-mail: abhik.mukherjee@saha.ac.in; Janaki, M. S., E-mail: ms.janaki@saha.ac.in; Kundu, Anjan, E-mail: anjan.kundu@saha.ac.in

2015-12-15

The bending of solitons in two dimensional plane is presented in the presence of weak and slowly varying inhomogeneous ion density for the propagation of ion acoustic soliton in unmagnetized cold plasma with isothermal electrons. Using reductive perturbation technique, a modified Kadomtsev-Petviashvili equation is obtained with a chosen unperturbed ion density profile. The exact solution of the equation shows that the phase of the solitary wave gets modified by a function related to the unperturbed inhomogeneous ion density causing the soliton to bend in the two dimensional plane, while the amplitude of the soliton remains constant.

Thermal Images of Seeds Obtained at Different Depths by Photoacoustic Microscopy (PAM)

NASA Astrophysics Data System (ADS)

Domínguez-Pacheco, A.; Hernández-Aguilar, C.; Cruz-Orea, A.

2015-06-01

The objective of the present study was to obtain thermal images of a broccoli seed ( Brassica oleracea) by photoacoustic microscopy, at different modulation frequencies of the incident light beam ((0.5, 1, 5, and 20) Hz). The thermal images obtained in the amplitude of the photoacoustic signal vary with each applied frequency. In the lowest light frequency modulation, there is greater thermal wave penetration in the sample. Likewise, the photoacoustic signal is modified according to the structural characteristics of the sample and the modulation frequency of the incident light. Different structural components could be seen by photothermal techniques, as shown in the present study.

Tendon material properties vary and are interdependent among turkey hindlimb muscles

PubMed Central

Matson, Andrew; Konow, Nicolai; Miller, Samuel; Konow, Pernille P.; Roberts, Thomas J.

2012-01-01

SUMMARY The material properties of a tendon affect its ability to store and return elastic energy, resist damage, provide mechanical feedback and amplify or attenuate muscle power. While the structural properties of a tendon are known to respond to a variety of stimuli, the extent to which material properties vary among individual muscles remains unclear. We studied the tendons of six different muscles in the hindlimb of Eastern wild turkeys to determine whether there was variation in elastic modulus, ultimate tensile strength and resilience. A hydraulic testing machine was used to measure tendon force during quasi-static lengthening, and a stress–strain curve was constructed. There was substantial variation in tendon material properties among different muscles. Average elastic modulus differed significantly between some tendons, and values for the six different tendons varied nearly twofold, from 829±140 to 1479±106 MPa. Tendons were stretched to failure, and the stress at failure, or ultimate tensile stress, was taken as a lower-limit estimate of tendon strength. Breaking tests for four of the tendons revealed significant variation in ultimate tensile stress, ranging from 66.83±14.34 to 112.37±9.39 MPa. Resilience, or the fraction of energy returned in cyclic length changes was generally high, and one of the four tendons tested was significantly different in resilience from the other tendons (range: 90.65±0.83 to 94.02±0.71%). An analysis of correlation between material properties revealed a positive relationship between ultimate tensile strength and elastic modulus (r2=0.79). Specifically, stiffer tendons were stronger, and we suggest that this correlation results from a constrained value of breaking strain, which did not vary significantly among tendons. This finding suggests an interdependence of material properties that may have a structural basis and may explain some adaptive responses observed in studies of tendon plasticity. PMID:22771746

The preference of probability over negative values in action selection.

PubMed

Neyedli, Heather F; Welsh, Timothy N

2015-01-01

It has previously been found that when participants are presented with a pair of motor prospects, they can select the prospect with the largest maximum expected gain (MEG). Many of those decisions, however, were trivial because of large differences in MEG between the prospects. The purpose of the present study was to explore participants' preferences when making non-trivial decisions between two motor prospects. Participants were presented with pairs of prospects that: 1) differed in MEG with either only the values or only the probabilities differing between the prospects; and 2) had similar MEG with one prospect having a larger probability of hitting the target and a higher penalty value and the other prospect a smaller probability of hitting the target but a lower penalty value. In different experiments, participants either had 400 ms or 2000 ms to decide between the prospects. It was found that participants chose the configuration with the larger MEG more often when the probability varied between prospects than when the value varied. In pairs with similar MEGs, participants preferred a larger probability of hitting the target over a smaller penalty value. These results indicate that participants prefer probability information over negative value information in a motor selection task.

The value of value of information: best informing research design and prioritization using current methods.

PubMed

Eckermann, Simon; Karnon, Jon; Willan, Andrew R

2010-01-01

Value of information (VOI) methods have been proposed as a systematic approach to inform optimal research design and prioritization. Four related questions arise that VOI methods could address. (i) Is further research for a health technology assessment (HTA) potentially worthwhile? (ii) Is the cost of a given research design less than its expected value? (iii) What is the optimal research design for an HTA? (iv) How can research funding be best prioritized across alternative HTAs? Following Occam's razor, we consider the usefulness of VOI methods in informing questions 1-4 relative to their simplicity of use. Expected value of perfect information (EVPI) with current information, while simple to calculate, is shown to provide neither a necessary nor a sufficient condition to address question 1, given that what EVPI needs to exceed varies with the cost of research design, which can vary from very large down to negligible. Hence, for any given HTA, EVPI does not discriminate, as it can be large and further research not worthwhile or small and further research worthwhile. In contrast, each of questions 1-4 are shown to be fully addressed (necessary and sufficient) where VOI methods are applied to maximize expected value of sample information (EVSI) minus expected costs across designs. In comparing complexity in use of VOI methods, applying the central limit theorem (CLT) simplifies analysis to enable easy estimation of EVSI and optimal overall research design, and has been shown to outperform bootstrapping, particularly with small samples. Consequently, VOI methods applying the CLT to inform optimal overall research design satisfy Occam's razor in both improving decision making and reducing complexity. Furthermore, they enable consideration of relevant decision contexts, including option value and opportunity cost of delay, time, imperfect implementation and optimal design across jurisdictions. More complex VOI methods such as bootstrapping of the expected value of

Cotton Defense Induction Patterns Under Spatially, Temporally and Quantitatively Varying Herbivory Levels.

PubMed

Eisenring, Michael; Meissle, Michael; Hagenbucher, Steffen; Naranjo, Steven E; Wettstein, Felix; Romeis, Jörg

2017-01-01

In its defense against herbivores, cotton ( Gossypium sp.) relies in part on the production of a set of inducible, non-volatile terpenoids. Under uniform damage levels, in planta allocation of induced cotton terpenoids has been found to be highest in youngest leaves, supporting assumptions of the optimal defense theory (ODT) which predicts that plants allocate defense compounds to tissues depending on their value and the likelihood of herbivore attack. However, our knowledge is limited on how varying, and thus more realistic, damage levels might affect cotton defense organization. We hypothesized that the allocation of terpenoids and densities of terpenoid-storing glands in leaves aligns with assumptions of the ODT, even when plants are subjected to temporally, spatially and quantitatively varying caterpillar ( Heliothis virescens ) damage. As expected, cotton plants allocated most of their defenses to their youngest leaves regardless of damage location. However, defense induction in older leaves varied with damage location. For at least 14 days after damage treatments ended, plants reallocated defense resources from previously young leaves to newly developed leaves. Furthermore, we observed a positive hyperbolic relationship between leaf damage area and both terpenoid concentrations and gland densities, indicating that cotton plants can fine-tune defense allocation. Although it appears that factors like vascular constraints and chemical properties of individual defense compounds can affect defense levels, our results overall demonstrate that induced defense organization of cotton subjected to varying damage treatments is in alignment with key assumptions of the ODT.

Cotton Defense Induction Patterns Under Spatially, Temporally and Quantitatively Varying Herbivory Levels

PubMed Central

Eisenring, Michael; Meissle, Michael; Hagenbucher, Steffen; Naranjo, Steven E.; Wettstein, Felix; Romeis, Jörg

2017-01-01

In its defense against herbivores, cotton (Gossypium sp.) relies in part on the production of a set of inducible, non-volatile terpenoids. Under uniform damage levels, in planta allocation of induced cotton terpenoids has been found to be highest in youngest leaves, supporting assumptions of the optimal defense theory (ODT) which predicts that plants allocate defense compounds to tissues depending on their value and the likelihood of herbivore attack. However, our knowledge is limited on how varying, and thus more realistic, damage levels might affect cotton defense organization. We hypothesized that the allocation of terpenoids and densities of terpenoid-storing glands in leaves aligns with assumptions of the ODT, even when plants are subjected to temporally, spatially and quantitatively varying caterpillar (Heliothis virescens) damage. As expected, cotton plants allocated most of their defenses to their youngest leaves regardless of damage location. However, defense induction in older leaves varied with damage location. For at least 14 days after damage treatments ended, plants reallocated defense resources from previously young leaves to newly developed leaves. Furthermore, we observed a positive hyperbolic relationship between leaf damage area and both terpenoid concentrations and gland densities, indicating that cotton plants can fine-tune defense allocation. Although it appears that factors like vascular constraints and chemical properties of individual defense compounds can affect defense levels, our results overall demonstrate that induced defense organization of cotton subjected to varying damage treatments is in alignment with key assumptions of the ODT. PMID:28270830

Estimation of Time-Varying Pilot Model Parameters

NASA Technical Reports Server (NTRS)

Zaal, Peter M. T.; Sweet, Barbara T.

2011-01-01

Human control behavior is rarely completely stationary over time due to fatigue or loss of attention. In addition, there are many control tasks for which human operators need to adapt their control strategy to vehicle dynamics that vary in time. In previous studies on the identification of time-varying pilot control behavior wavelets were used to estimate the time-varying frequency response functions. However, the estimation of time-varying pilot model parameters was not considered. Estimating these parameters can be a valuable tool for the quantification of different aspects of human time-varying manual control. This paper presents two methods for the estimation of time-varying pilot model parameters, a two-step method using wavelets and a windowed maximum likelihood estimation method. The methods are evaluated using simulations of a closed-loop control task with time-varying pilot equalization and vehicle dynamics. Simulations are performed with and without remnant. Both methods give accurate results when no pilot remnant is present. The wavelet transform is very sensitive to measurement noise, resulting in inaccurate parameter estimates when considerable pilot remnant is present. Maximum likelihood estimation is less sensitive to pilot remnant, but cannot detect fast changes in pilot control behavior.

Calibrations between chlorophyll meter values and chlorophyll contents vary as the result of differences in leaf structure

USDA-ARS?s Scientific Manuscript database

In order to relate leaf chlorophyll meter values with total leaf chlorophyll contents (µg cm-2), calibration equations are established with measured data on leaves. Many studies have documented differences in calibration equations using different species and using different growing conditions for th...

Development and Integration of Professional Core Values Among Practicing Clinicians.

PubMed

McGinnis, Patricia Quinn; Guenther, Lee Ann; Wainwright, Susan F

2016-09-01

The physical therapy profession has adopted professional core values, which define expected values for its members, and developed a self-assessment tool with sample behaviors for each of the 7 core values. However, evidence related to the integration of these core values into practice is limited. The aims of this study were: (1) to gain insight into physical therapists' development of professional core values and (2) to gain insight into participants' integration of professional core values into clinical practice. A qualitative design permitted in-depth exploration of the development and integration of the American Physical Therapy Association's professional core values into physical therapist practice. Twenty practicing physical therapists were purposefully selected to explore the role of varied professional, postprofessional, and continuing education experiences related to exposure to professional values. The Core Values Self-Assessment and résumé sort served as prompts for reflection via semistructured interviews. Three themes were identified: (1) personal values were the foundation for developing professional values, which were further shaped by academic and clinical experiences, (2) core values were integrated into practice independent of practice setting and varied career paths, and (3) participants described the following professional core values as well integrated into their practice: integrity, compassion/caring, and accountability. Social responsibility was an area consistently identified as not being integrated into their practice. The Core Values Self-Assessment tool is a consensus-based document developed through a Delphi process. Future studies to establish reliability and construct validity of the tool may be warranted. Gaining an in-depth understanding of how practicing clinicians incorporate professional core values into clinical practice may shed light on the relationship between core values mastery and its impact on patient care. Findings may

First attempts to obtain a reference drift curve for traditional olive grove's plantations following ISO 22866.

PubMed

Gil, Emilio; Llorens, Jordi; Gallart, Montserrat; Gil-Ribes, Jesús A; Miranda-Fuentes, Antonio

2018-06-15

The current standard for the field measurements of spray drift (ISO 22866) is the only official standard for drift measurements in field conditions for all type of crops, including bushes and trees. A series of field trials following all the requirements established in the standard were arranged in a traditional olive grove in Córdoba (south of Spain). The aims of the study were to evaluate the applicability of the current standard procedure to the particular conditions of traditional olive trees plantations, to evaluate the critical requirements for performing the tests and to obtain a specific drift curve for such as important and specific crop as olive trees in traditional plantations, considering the enormous area covered by this type of crop all around the world. Results showed that the field trials incur a very complex process due to the particular conditions of the crop and the very precise environmental requirements. Furthermore, the trials offered a very low level of repeatability as the drift values varied significantly from one spray application to the next, with the obtained results being closely related to the wind speed, even when considering the standard minimum value of 1 m·s -1 . The collector's placement with respect to the position of the isolated trees was determined as being critical since this substantially modifies the ground deposit in the first 5 m. Even though, a new drift curve for olive trees in traditional plantation has been defined, giving an interesting tool for regulatory aspects. Conclusions indicated that a deep review of the official standard is needed to allow its application to the most relevant orchard/fruit crops. Copyright © 2018 Elsevier B.V. All rights reserved.

The place-value of a digit in multi-digit numbers is processed automatically.

PubMed

Kallai, Arava Y; Tzelgov, Joseph

2012-09-01

The automatic processing of the place-value of digits in a multi-digit number was investigated in 4 experiments. Experiment 1 and two control experiments employed a numerical comparison task in which the place-value of a non-zero digit was varied in a string composed of zeros. Experiment 2 employed a physical comparison task in which strings of digits varied in their physical sizes. In both types of tasks, the place-value of the non-zero digit in the string was irrelevant to the task performed. Interference of the place-value information was found in both tasks. When the non-zero digit occupied a lower place-value, it was recognized slower as a larger digit or as written in a larger font size. We concluded that place-value in a multi-digit number is processed automatically. These results support the notion of a decomposed representation of multi-digit numbers in memory. PsycINFO Database Record (c) 2012 APA, all rights reserved.

Finite-time synchronization for memristor-based neural networks with time-varying delays.

PubMed

Abdurahman, Abdujelil; Jiang, Haijun; Teng, Zhidong

2015-09-01

Memristive network exhibits state-dependent switching behaviors due to the physical properties of memristor, which is an ideal tool to mimic the functionalities of the human brain. In this paper, finite-time synchronization is considered for a class of memristor-based neural networks with time-varying delays. Based on the theory of differential equations with discontinuous right-hand side, several new sufficient conditions ensuring the finite-time synchronization of memristor-based chaotic neural networks are obtained by using analysis technique, finite time stability theorem and adding a suitable feedback controller. Besides, the upper bounds of the settling time of synchronization are estimated. Finally, a numerical example is given to show the effectiveness and feasibility of the obtained results. Copyright © 2015 Elsevier Ltd. All rights reserved.

ΔT and tidal acceleration values from three european medieval eclipses

NASA Astrophysics Data System (ADS)

Martinez, M. J.; Marco, F. J.

2011-10-01

There are many possible reasons for the fact that the rate of rotation of the Earth is slowly decreasing in time, being the most important the tidal friction. Since Universal Time (UT) is a time scale based on the rotation of the Earth and ΔT defined as the difference between the uniform time-scale (Dynamical Time), and the Universal Time, clearly that ΔT will vary with time. The problem is that this variation is not uniform, existing irregular fluctuations. In addition, it is not possible to predict exact values for ΔT, being the only possibility its deduction a posteriori from observations. ΔT is strongly related with occultations and eclipses, because it is used for the calculation of exact times of the event, and for determining the position of the central line or the zone of visibility. In this sense, a value ΔT =3600s is roughly equivalent to a shift of 15. in longitude. Past values of ΔT can be deduced from historical astronomical observations such as ancient eclipses which have been widely studied by F.R. Stephenson [3] and [4] who has even obtained an approximation fitted with cubic splines for ΔT from -500 to +1950. This approximation is nowadays widely used in astronomical calculations. The derived relative error from ΔT obtained from ancient eclipsed is quite large, mainly because of the large width of the totality zone and the inaccuracy in the definition of the observational place. A possibility to partially solve these former problems is the analysis of total eclipse records from multiple sites, which could provide a narrow parameter range. In addition, The conjunct analysis of these astronomical phenomena is useful for determining a range of ΔT in function of the tidal acceleration of the Moon. Further discussion about these eclipses in under review.

Evaluation of assigned-value uncertainty for complex calibrator value assignment processes: a prealbumin example.

PubMed

Middleton, John; Vaks, Jeffrey E

2007-04-01

Errors of calibrator-assigned values lead to errors in the testing of patient samples. The ability to estimate the uncertainties of calibrator-assigned values and other variables minimizes errors in testing processes. International Organization of Standardization guidelines provide simple equations for the estimation of calibrator uncertainty with simple value-assignment processes, but other methods are needed to estimate uncertainty in complex processes. We estimated the assigned-value uncertainty with a Monte Carlo computer simulation of a complex value-assignment process, based on a formalized description of the process, with measurement parameters estimated experimentally. This method was applied to study uncertainty of a multilevel calibrator value assignment for a prealbumin immunoassay. The simulation results showed that the component of the uncertainty added by the process of value transfer from the reference material CRM470 to the calibrator is smaller than that of the reference material itself (<0.8% vs 3.7%). Varying the process parameters in the simulation model allowed for optimizing the process, while keeping the added uncertainty small. The patient result uncertainty caused by the calibrator uncertainty was also found to be small. This method of estimating uncertainty is a powerful tool that allows for estimation of calibrator uncertainty for optimization of various value assignment processes, with a reduced number of measurements and reagent costs, while satisfying the requirements to uncertainty. The new method expands and augments existing methods to allow estimation of uncertainty in complex processes.

Patterns of Wildlife Value Orientations

Treesearch

Harry C. Zinn; Michael J. Manfredo; Susan C. Barro

2002-01-01

Public value orientations toward wildlife may be growing less utilitarian and more protectionist. To better understand one aspect of this trend, we investigated patterns of wildlife value orientations within families. Using a mail survey, we sampled Pennsylvania and Colorado hunting license holders 50 or older; obtaining a 54% response rate (n = 599). Males (94% of...

Varying negative work assistance at the ankle with a soft exosuit during loaded walking.

PubMed

Malcolm, Philippe; Lee, Sangjun; Crea, Simona; Siviy, Christopher; Saucedo, Fabricio; Galiana, Ignacio; Panizzolo, Fausto A; Holt, Kenneth G; Walsh, Conor J

2017-06-26

Only very recently, studies have shown that it is possible to reduce the metabolic rate of unloaded and loaded walking using robotic ankle exoskeletons. Some studies obtained this result by means of high positive work assistance while others combined negative and positive work assistance. There is no consensus about the isolated contribution of negative work assistance. Therefore, the aim of the present study is to examine the effect of varying negative work assistance at the ankle joint while maintaining a fixed level of positive work assistance with a multi-articular soft exosuit. We tested eight participants during walking at 1.5 ms -1 with a 23-kg backpack. Participants wore a version of the exosuit that assisted plantarflexion via Bowden cables tethered to an off-board actuation platform. In four active conditions we provided different rates of exosuit bilateral ankle negative work assistance ranging from 0.015 to 0.037 W kg -1 and a fixed rate of positive work assistance of 0.19 W kg -1 . All active conditions significantly reduced metabolic rate by 11 to 15% compared to a reference condition, where the participants wore the exosuit but no assistance was provided. We found no significant effect of negative work assistance. However, there was a trend (p = .08) toward greater reduction in metabolic rate with increasing negative work assistance, which could be explained by observed reductions in biological ankle and hip joint power and moment. The non-significant trend of increasing negative work assistance with increasing reductions in metabolic rate motivates the value in further studies on the relative effects of negative and positive work assistance. There may be benefit in varying negative work over a greater range or in isolation from positive work assistance.

Linear-parameter-varying gain-scheduled control of aerospace systems

NASA Astrophysics Data System (ADS)

Barker, Jeffrey Michael

The dynamics of many aerospace systems vary significantly as a function of flight condition. Robust control provides methods of guaranteeing performance and stability goals across flight conditions. In mu-syntthesis, changes to the dynamical system are primarily treated as uncertainty. This method has been successfully applied to many control problems, and here is applied to flutter control. More recently, two techniques for generating robust gain-scheduled controller have been developed. Linear fractional transformation (LFT) gain-scheduled control is an extension of mu-synthesis in which the plant and controller are explicit functions of parameters measurable in real-time. This LFT gain-scheduled control technique is applied to the Benchmark Active Control Technology (BACT) wing, and compared with mu-synthesis control. Linear parameter-varying (LPV) gain-scheduled control is an extension of Hinfinity control to parameter varying systems. LPV gain-scheduled control directly incorporates bounds on the rate of change of the scheduling parameters, and often reduces conservatism inherent in LFT gain-scheduled control. Gain-scheduled LPV control of the BACT wing compares very favorably with the LFT controller. Gain-scheduled LPV controllers are generated for the lateral-directional and longitudinal axes of the Innovative Control Effectors (ICE) aircraft and implemented in nonlinear simulations and real-time piloted nonlinear simulations. Cooper-Harper and pilot-induced oscillation ratings were obtained for an initial design, a reference aircraft and a redesign. Piloted simulation results for the initial LPV gain-scheduled control of the ICE aircraft are compared with results for a conventional fighter aircraft in discrete pitch and roll angle tracking tasks. The results for the redesigned controller are significantly better than both the previous LPV controller and the conventional aircraft.

Incidence of Artifacts and Deviating Values in Research Data Obtained from an Anesthesia Information Management System in Children.

PubMed

Hoorweg, Anne-Lee J; Pasma, Wietze; van Wolfswinkel, Leo; de Graaff, Jurgen C

2018-02-01

Vital parameter data collected in anesthesia information management systems are often used for clinical research. The validity of this type of research is dependent on the number of artifacts. In this prospective observational cohort study, the incidence of artifacts in anesthesia information management system data was investigated in children undergoing anesthesia for noncardiac procedures. Secondary outcomes included the incidence of artifacts among deviating and nondeviating values, among the anesthesia phases, and among different anesthetic techniques. We included 136 anesthetics representing 10,236 min of anesthesia time. The incidence of artifacts was 0.5% for heart rate (95% CI: 0.4 to 0.7%), 1.3% for oxygen saturation (1.1 to 1.5%), 7.5% for end-tidal carbon dioxide (6.9 to 8.0%), 5.0% for noninvasive blood pressure (4.0 to 6.0%), and 7.3% for invasive blood pressure (5.9 to 8.8%). The incidence of artifacts among deviating values was 3.1% for heart rate (2.1 to 4.4%), 10.8% for oxygen saturation (7.6 to 14.8%), 14.1% for end-tidal carbon dioxide (13.0 to 15.2%), 14.4% for noninvasive blood pressure (10.3 to 19.4%), and 38.4% for invasive blood pressure (30.3 to 47.1%). Not all values in anesthesia information management systems are valid. The incidence of artifacts stored in the present pediatric anesthesia practice was low for heart rate and oxygen saturation, whereas noninvasive and invasive blood pressure and end-tidal carbon dioxide had higher artifact incidences. Deviating values are more often artifacts than values in a normal range, and artifacts are associated with the phase of anesthesia and anesthetic technique. Development of (automatic) data validation systems or solutions to deal with artifacts in data is warranted.

Inferring time-varying recharge from inverse analysis of long-term water levels

NASA Astrophysics Data System (ADS)

Dickinson, Jesse E.; Hanson, R. T.; Ferré, T. P. A.; Leake, S. A.

2004-07-01

Water levels in aquifers typically vary in response to time-varying rates of recharge, suggesting the possibility of inferring time-varying recharge rates on the basis of long-term water level records. Presumably, in the southwestern United States (Arizona, Nevada, New Mexico, southern California, and southern Utah), rates of mountain front recharge to alluvial aquifers depend on variations in precipitation rates due to known climate cycles such as the El Niño-Southern Oscillation index and the Pacific Decadal Oscillation. This investigation examined the inverse application of a one-dimensional analytical model for periodic flow described by Lloyd R. Townley in 1995 to estimate periodic recharge variations on the basis of variations in long-term water level records using southwest aquifers as the case study. Time-varying water level records at various locations along the flow line were obtained by simulation of forward models of synthetic basins with applied sinusoidal recharge of either a single period or composite of multiple periods of length similar to known climate cycles. Periodic water level components, reconstructed using singular spectrum analysis (SSA), were used to calibrate the analytical model to estimate each recharge component. The results demonstrated that periodic recharge estimates were most accurate in basins with nearly uniform transmissivity and the accuracy of the recharge estimates depends on monitoring well location. A case study of the San Pedro Basin, Arizona, is presented as an example of calibrating the analytical model to real data.

Inferring time‐varying recharge from inverse analysis of long‐term water levels

USGS Publications Warehouse

Dickinson, Jesse; Hanson, R.T.; Ferré, T.P.A.; Leake, S.A.

2004-01-01

Water levels in aquifers typically vary in response to time‐varying rates of recharge, suggesting the possibility of inferring time‐varying recharge rates on the basis of long‐term water level records. Presumably, in the southwestern United States (Arizona, Nevada, New Mexico, southern California, and southern Utah), rates of mountain front recharge to alluvial aquifers depend on variations in precipitation rates due to known climate cycles such as the El Niño‐Southern Oscillation index and the Pacific Decadal Oscillation. This investigation examined the inverse application of a one‐dimensional analytical model for periodic flow described by Lloyd R. Townley in 1995 to estimate periodic recharge variations on the basis of variations in long‐term water level records using southwest aquifers as the case study. Time‐varying water level records at various locations along the flow line were obtained by simulation of forward models of synthetic basins with applied sinusoidal recharge of either a single period or composite of multiple periods of length similar to known climate cycles. Periodic water level components, reconstructed using singular spectrum analysis (SSA), were used to calibrate the analytical model to estimate each recharge component. The results demonstrated that periodic recharge estimates were most accurate in basins with nearly uniform transmissivity and the accuracy of the recharge estimates depends on monitoring well location. A case study of the San Pedro Basin, Arizona, is presented as an example of calibrating the analytical model to real data.

Applying the Expectancy-Value Model to understand health values.

PubMed

Zhang, Xu-Hao; Xie, Feng; Wee, Hwee-Lin; Thumboo, Julian; Li, Shu-Chuen

2008-03-01

Expectancy-Value Model (EVM) is the most structured model in psychology to predict attitudes by measuring attitudinal attributes (AAs) and relevant external variables. Because health value could be categorized as attitude, we aimed to apply EVM to explore its usefulness in explaining variances in health values and investigate underlying factors. Focus group discussion was carried out to identify the most common and significant AAs toward 5 different health states (coded as 11111, 11121, 21221, 32323, and 33333 in EuroQol Five-Dimension (EQ-5D) descriptive system). AAs were measured in a sum of multiplications of subjective probability (expectancy) and perceived value of attributes with 7-point Likert scales. Health values were measured using visual analog scales (VAS, range 0-1). External variables (age, sex, ethnicity, education, housing, marital status, and concurrent chronic diseases) were also incorporated into survey questionnaire distributed by convenience sampling among eligible respondents. Univariate analyses were used to identify external variables causing significant differences in VAS. Multiple linear regression model (MLR) and hierarchical regression model were used to investigate the explanatory power of AAs and possible significant external variable(s) separately or in combination, for each individual health state and a mixed scenario of five states, respectively. Four AAs were identified, namely, "worsening your quality of life in terms of health" (WQoL), "adding a burden to your family" (BTF), "making you less independent" (MLI) and "unable to work or study" (UWS). Data were analyzed based on 232 respondents (mean [SD] age: 27.7 [15.07] years, 49.1% female). Health values varied significantly across 5 health states, ranging from 0.12 (33333) to 0.97 (11111). With no significant external variables identified, EVM explained up to 62% of the variances in health values across 5 health states. The explanatory power of 4 AAs were found to be between 13

Recommended Values of the Fundamental Physical Constants: A Status Report

PubMed Central

Taylor, Barry N.; Cohen, E. Richard

1990-01-01

We summarize the principal advances made in the fundamental physical constants field since the completion of the 1986 CODATA least-squares adjustment of the constants and discuss their implications for both the 1986 set of recommended values and the next least-squares adjustment. In general, the new results lead to values of the constants with uncertainties 5 to 7 times smaller than the uncertainties assigned the 1986 values. However, the changes in the values themselves are less than twice the 1986 assigned one-standard-deviation uncertainties and thus are not highly significant. Although much new data has become available since 1986, three new results dominate the analysis: a value of the Planck constant obtained from a realization of the watt; a value of the fine-structure constant obtained from the magnetic moment anomaly of the electron; and a value of the molar gas constant obtained from the speed of sound in argon. Because of their dominant role in determining the values and uncertainties of many of the constants, it is highly desirable that additional results of comparable uncertainty that corroborate these three data items be obtained before the next adjustment is carried out. Until then, the 1986 CODATA set of recommended values will remain the set of choice. PMID:28179787

Passivity of memristive BAM neural networks with leakage and additive time-varying delays

NASA Astrophysics Data System (ADS)

Wang, Weiping; Wang, Meiqi; Luo, Xiong; Li, Lixiang; Zhao, Wenbing; Liu, Linlin; Ping, Yuan

2018-02-01

This paper investigates the passivity of memristive bidirectional associate memory neural networks (MBAMNNs) with leakage and additive time-varying delays. Based on some useful inequalities and appropriate Lyapunov-Krasovskii functionals (LKFs), several delay-dependent conditions for passivity performance are obtained in linear matrix inequalities (LMIs). Moreover, the leakage delays as well as additive delays are considered separately. Finally, numerical simulations are provided to demonstrate the feasibility of the theoretical results.

Characteristics of women obtaining induced abortions in selected low- and middle-income countries

PubMed Central

Desai, Sheila; Crowell, Marjorie; Sedgh, Gilda; Singh, Susheela

2017-01-01

Background In 2010–2014, approximately 86% of abortions took place in low- and middle-income countries (LMICs). Although abortion incidence varies minimally across geographical regions, it varies widely by subregion and within countries by subgroups of women. Differential abortion levels stem from variation in the level of unintended pregnancies and in the likelihood that women with unintended pregnancies obtain abortions. Objectives To examine the characteristics of women obtaining induced abortions in LMICs. Methods We use data from official statistics, population-based surveys, and abortion patient surveys to examine variation in the percentage distribution of abortions and abortion rates by age at abortion, marital status, parity, wealth, education, and residence. We analyze data from five countries in Africa, 13 in Asia, eight in Europe, and two in Latin America and the Caribbean (LAC). Results Women across all sociodemographic subgroups obtain abortions. In most countries, women aged 20–29 obtained the highest proportion of abortions, and while adolescents obtained a substantial fraction of abortions, they do not make up a disproportionate share. Region-specific patterns were observed in the distribution of abortions by parity. In many countries, a higher fraction of abortions occurred among women of high socioeconomic status, as measured by wealth status, educational attainment, and urban residence. Due to limited data on marital status, it is unknown whether married or unmarried women make up a larger share of abortions. Conclusions These findings help to identify subgroups of women with disproportionate levels of abortion, and can inform policies and programs to reduce the incidence of unintended pregnancies; and in LMICs that have restrictive abortion laws, these findings can also inform policies to minimize the consequences of unsafe abortion and motivate liberalization of abortion laws. Program planners, policymakers, and advocates can use this

Comparison of the diagnostic performance of bacterial culture of nasopharyngeal swab and bronchoalveolar lavage fluid samples obtained from calves with bovine respiratory disease.

PubMed

Capik, Sarah F; White, Brad J; Lubbers, Brian V; Apley, Michael D; DeDonder, Keith D; Larson, Robert L; Harhay, Greg P; Chitko-McKown, Carol G; Harhay, Dayna M; Kalbfleisch, Ted S; Schuller, Gennie; Clawson, Michael L

2017-03-01

OBJECTIVE To compare predictive values, extent of agreement, and gamithromycin susceptibility between bacterial culture results of nasopharyngeal swab (NPS) and bronchoalveolar lavage fluid (BALF) samples obtained from calves with bovine respiratory disease (BRD). ANIMALS 28 beef calves with clinical BRD. PROCEDURES Pooled bilateral NPS samples and BALF samples were obtained for bacterial culture from calves immediately before and at various times during the 5 days after gamithromycin (6 mg/kg, SC, once) administration. For each culture-positive sample, up to 12 Mannheimia haemolytica, 6 Pasteurella multocida, and 6 Histophilus somni colonies underwent gamithromycin susceptibility testing. Whole-genome sequencing was performed on all M haemolytica isolates. For paired NPS and BALF samples collected 5 days after gamithromycin administration, the positive and negative predictive values for culture results of NPS samples relative to those of BALF samples and the extent of agreement between the sampling methods were determined. RESULTS Positive and negative predictive values of NPS samples were 67% and 100% for M haemolytica, 75% and 100% for P multocida, and 100% and 96% for H somni. Extent of agreement between results for NPS and BALF samples was substantial for M haemolytica (κ, 0.71) and H somni (κ, 0.78) and almost perfect for P multocida (κ, 0.81). Gamithromycin susceptibility varied within the same sample and between paired NPS and BALF samples. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated culture results of NPS and BALF samples from calves with BRD should be interpreted cautiously considering disease prevalence within the population, sample collection relative to antimicrobial administration, and limitations of diagnostic testing methods.

Failure Modes in Capacitors When Tested Under a Time-Varying Stress

NASA Technical Reports Server (NTRS)

Liu, David (Donhang)

2011-01-01

Steady step surge testing (SSST) is widely applied to screen out potential power-on failures in solid tantalum capacitors. The test simulates the power supply's on and off characteristics. Power-on failure has been the prevalent failure mechanism for solid tantalum capacitors for decoupling applications. On the other hand, the SSST can also be reviewed as an electrically destructive test under a time-varying stress. It consists of rapidly charging the capacitor with incremental voltage increases, through a low resistance in series, until the capacitor under test is electrically shorted. Highly accelerated life testing (HALT) is usually a time-efficient method for determining the failure mechanism in capacitors; however, a destructive test under a time-varying stress like SSST is even more effective. It normally takes days to complete a HALT test, but it only takes minutes for a time-varying stress test to produce failures. The advantage of incorporating specific time-varying stress into a statistical model is significant in providing an alternative life test method for quickly revealing the failure modes in capacitors. In this paper, a time-varying stress has been incorporated into the Weibull model to characterize the failure modes. The SSST circuit and transient conditions to correctly test the capacitors is discussed. Finally, the SSST was applied for testing polymer aluminum capacitors (PA capacitors), Ta capacitors, and multi-layer ceramic capacitors with both precious metal electrode (PME) and base-metal-electrodes (BME). It appears that testing results are directly associated to the dielectric layer breakdown in PA and Ta capacitors and are independent on the capacitor values, the way the capacitors being built, and the manufactures. The testing results also reveal that ceramic capacitors exhibit breakdown voltages more than 20 times the rated voltage, and the breakdown voltages are inverse proportional to the dielectric layer thickness. The possibility of

Analysis of randomly time varying systems by gaussian closure technique

NASA Astrophysics Data System (ADS)

Dash, P. K.; Iyengar, R. N.

1982-07-01

The Gaussian probability closure technique is applied to study the random response of multidegree of freedom stochastically time varying systems under non-Gaussian excitations. Under the assumption that the response, the coefficient and the excitation processes are jointly Gaussian, deterministic equations are derived for the first two response moments. It is further shown that this technique leads to the best Gaussian estimate in a minimum mean square error sense. An example problem is solved which demonstrates the capability of this technique for handling non-linearity, stochastic system parameters and amplitude limited responses in a unified manner. Numerical results obtained through the Gaussian closure technique compare well with the exact solutions.

Probabilities and statistics for backscatter estimates obtained by a scatterometer with applications to new scatterometer design data

NASA Technical Reports Server (NTRS)

Pierson, Willard J., Jr.

1989-01-01

The values of the Normalized Radar Backscattering Cross Section (NRCS), sigma (o), obtained by a scatterometer are random variables whose variance is a known function of the expected value. The probability density function can be obtained from the normal distribution. Models for the expected value obtain it as a function of the properties of the waves on the ocean and the winds that generated the waves. Point estimates of the expected value were found from various statistics given the parameters that define the probability density function for each value. Random intervals were derived with a preassigned probability of containing that value. A statistical test to determine whether or not successive values of sigma (o) are truly independent was derived. The maximum likelihood estimates for wind speed and direction were found, given a model for backscatter as a function of the properties of the waves on the ocean. These estimates are biased as a result of the terms in the equation that involve natural logarithms, and calculations of the point estimates of the maximum likelihood values are used to show that the contributions of the logarithmic terms are negligible and that the terms can be omitted.

Estimating the impact of somatic cell count on the value of milk utilising parameters obtained from the published literature.

PubMed

Geary, Una; Lopez-Villalobos, Nicolas; O'Brien, Bernadette; Garrick, Dorian J; Shalloo, Laurence

2014-05-01

The impact of mastitis on milk value per litre independent of the effect of mastitis on milk volume, was quantified for Ireland using a meta-analysis and a processing sector model. Changes in raw milk composition, cheese processing and composition associated with increased bulk milk somatic cell count (BMSCC) were incorporated into the model. Processing costs and market values were representative of current industry values. It was assumed that as BMSCC increased (i) milk fat and milk protein increased and milk lactose decreased, (ii) fat and protein recoveries decreased, (iii) cheese protein decreased and cheese moisture increased. Five BMSCC categories were examined from ⩽100 000 to >400 000 cells/ml. The analysis showed that as BMSCC increased the production quantities reduced. An increase in BMSCC from 100 000 to >400 000 cells/ml saw a reduction in net revenue of 3·2% per annum (€51·3 million) which corresponded to a reduction in the value of raw milk of €0·0096 cents/l.

[Value of liquid-based cytology of brushing specimens obtained via fiberoptic bronchoscopy for the diagnosis of lung cancer].

PubMed

Zhao, Huan; Guo, Huiqin; Zhang, Chuanxin; Zhao, Linlin; Cao, Jian; Pan, Qinjing

2015-06-01

To investigate the value of the liquid-based cytology (LBC) of brushing specimens obtained via fiberoptic bronchoscopy for clinical diagnosis of lung cancer. We retrospectively analyzed the LBC cases in our hospital from January 2011 to May 2012, and evaluate its role in the diagnosis of lung cancer. The clinical data of a total of 4 380 cases were reviewed and 3 763 of them had histopathological or clinical follow-up results (including 3 306 lung cancer cases and 457 benign lesion cases). The sensitivity, specificity, and accuracy of LBC diagnosis for lung cancer were 72.4% (2 392/3 306), 99.3% (454/457) and 75.6% (2 846/3 763), respectively. Of the 1 992 lung cancer cases diagnosed by brushing LBC, 528 cases (26.5%) were failed to take forceps biopsy and 113 cases (5.7%) showed negative forceps biopsy results. The accurate rate of subtyping of LBC for non-small cell carcinoma and small cell carcinoma was 99.0% (1 487/1 502) (P < 0.001). Take the resection histopathology as gold standard, the accurate rates of subtyping squamous cell carcinoma, adenocarcinoma and small cell carcinoma by LBC were 95.6% (351/367), 95.6% (351/367) and 100% (367/367), respectively, (P < 0.001). The accurate rates of subtyping of squamous cell carcinoma, adenocarcinoma and small cell carcinoma by forceps biopsy were 97.0% (293/302), 97.4% (294/302) and 99.7% (301/302), respectively, (Kappa = 0.895, P < 0.001). There was no significant difference in subtyping respectively between forceps biopsy and brushing LBC (P > 0.05). Fiberoptic bronchoscopic brushing liquid-based cytology can significantly improve the detection rate of lung cancer, and have a high specificity and accurate rate of subtyping. It is an effective tool for the diagnosis and subtyping of lung cancer.

Estimating time-varying RSA to examine psychophysiological linkage of marital dyads.

PubMed

Gates, Kathleen M; Gatzke-Kopp, Lisa M; Sandsten, Maria; Blandon, Alysia Y

2015-08-01

One of the primary tenets of polyvagal theory dictates that parasympathetic influence on heart rate, often estimated by respiratory sinus arrhythmia (RSA), shifts rapidly in response to changing environmental demands. The current standard analytic approach of aggregating RSA estimates across time to arrive at one value fails to capture this dynamic property within individuals. By utilizing recent methodological developments that enable precise RSA estimates at smaller time intervals, we demonstrate the utility of computing time-varying RSA for assessing psychophysiological linkage (or synchrony) in husband-wife dyads using time-locked data collected in a naturalistic setting. © 2015 Society for Psychophysiological Research.

Pre-Licensed Nursing Students Rate Professional Values

ERIC Educational Resources Information Center

Garee, Denise L.

2016-01-01

Ethical decision making of new nurses relies on professional values and moral development obtained during training. This descriptive, comparative study demonstrated the importance values attributed to the items of the Nurses' Professional Values Scale-Revised (Weis & Schank, 2009), by a sample of senior ADN and BSN students from across the…

Ethics education for health professionals: a values based approach.

PubMed

Godbold, Rosemary; Lees, Amanda

2013-11-01

It is now widely accepted that ethics is an essential part of educating health professionals. Despite a clear mandate to educators, there are differing approaches, in particular, how and where ethics is positioned in training programmes, underpinning philosophies and optimal modes of assessment. This paper explores varying practices and argues for a values based approach to ethics education. It then explores the possibility of using a web-based technology, the Values Exchange, to facilitate a values based approach. It uses the findings of a small scale study to signal the potential of the Values Exchange for engaging, meaningful and applied ethics education. Copyright © 2013 Elsevier Ltd. All rights reserved.

Hematological parameters in relation to age, sex and biochemical values for mute swans (Cygnus olor).

PubMed

Dolka, B; Włodarczyk, R; Zbikowski, A; Dolka, I; Szeleszczuk, P; Kluciński, W

2014-06-01

The knowledge of the correct morphological and biochemical parameters in mute swans is an important indicator of their health status, body condition, adaptation to habitat and useful diagnostic tools in veterinary practice and ecological research. The aim of the study was to obtain hematological parameters in relation to age, sex and serum biochemistry values in wild-living mute swans. We found the significant differences in the erythrocyte count, hematocrit, hemoglobin concentration and erythrocyte sedimentation rate in relation to age of mute swans. There were no differences in hematological values between males and females. The leukogram and H/L ratio did not vary by age and sex in swans. Among of biochemical parameters the slightly increased AST, ALP, CK, K, urea, decreased CHOL and TG values were recorded. As far as we know, this is the first study in which the morphometric parameters of blood cells in mute swans were presented. We found extremely low concentration of lead in blood (at subthreshold level). No blood parasites were found in blood smears. The analysis of body mass and biometric parameters revealed a significant differences dependent on age and sex. No differences in the scaled mass index were found. Our results represent a normal hematologic and blood chemistry values and age-sex related changes, as reference values for the mute swan.

Strong surface enhanced Raman scattering from gold nanoarrays obtained by direct laser writing

NASA Astrophysics Data System (ADS)

Ivanov, V. G.; Todorov, N. D.; Petrov, L. S.; Ritacco, T.; Giocondo, M.; Vlakhov, E. S.

2016-10-01

We report for surface enhanced Raman scattering (SERS) from arrays of gold nanoparticles produced by 2-photons photo-reduction of the metallic precursor (HAuCl4) hosted in a Poly-Vinyl Alcohol (PVA) matrix, on glass substrates. Samples with the same pattern but featuring different nanoparticles size and density were obtained by varying the writing laser power and scanning speed. The Raman spectra were recorded from samples immersed in a solution of rhodamine-6G (R6G), as well as, after exposure of the samples in xylene. SERS enhancement factors of up to ∼104 were obtained for both analytes. The measurements show that the SERS enhancement is maximized on golden strips produced at higher writing laser power and lower scanning speed, where closer nanoparticles packing is obtained..

Sleep-wake time perception varies by direct or indirect query.

PubMed

Alameddine, Y; Ellenbogen, J M; Bianchi, M T

2015-01-15

The diagnosis of insomnia rests on self-report of difficulty initiating or maintaining sleep. However, subjective reports may be unreliable, and possibly may vary by the method of inquiry. We investigated this possibility by comparing within-individual response to direct versus indirect time queries after overnight polysomnography. We obtained self-reported sleep-wake times via morning questionnaires in 879 consecutive adult diagnostic polysomnograms. Responses were compared within subjects (direct versus indirect query) and across groups defined by apnea-hypopnea index and by self-reported insomnia symptoms in pre-sleep questionnaires. Direct queries required a time duration response, while indirect queries required clock times from which we calculated time durations. Direct and indirect queries of sleep latency were the same in only 41% of cases, and total sleep time queries matched in only 5.4%. For both latency and total sleep, the most common discrepancy involved the indirect value being larger than the direct response. The discrepancy between direct and indirect queries was not related to objective sleep metrics. The degree of discrepancy was not related to the presence of insomnia symptoms, although patients reporting insomnia symptoms showed underestimation of total sleep duration by direct response. Self-reported sleep latency and total sleep time are often internally inconsistent when comparing direct and indirect survey queries of each measure. These discrepancies represent substantive challenges to effective clinical practice, particularly when diagnosis and management depends on self-reported sleep patterns, as with insomnia. Although self-reported sleep-wake times remains fundamental to clinical practice, objective measures provide clinically relevant adjunctive information. © 2015 American Academy of Sleep Medicine.

Controversy in the allometric application of fixed- versus varying-exponent models: a statistical and mathematical perspective.

PubMed

Tang, Huadong; Hussain, Azher; Leal, Mauricio; Fluhler, Eric; Mayersohn, Michael

2011-02-01

This commentary is a reply to a recent article by Mahmood commenting on the authors' article on the use of fixed-exponent allometry in predicting human clearance. The commentary discusses eight issues that are related to criticisms made in Mahmood's article and examines the controversies (fixed-exponent vs. varying-exponent allometry) from the perspective of statistics and mathematics. The key conclusion is that any allometric method, which is to establish a power function based on a limited number of animal species and to extrapolate the resulting power function to human values (varying-exponent allometry), is infused with fundamental statistical errors. Copyright © 2010 Wiley-Liss, Inc.

Exploring the Value Orientations of Inuit and White Students: An Empirical Inquiry.

ERIC Educational Resources Information Center

Roberts, Lance W.; And Others

1989-01-01

Finds that, among 46 Inuit and 11 White 10-16-year-old students in the Northwest Territories (Canada), Inuit students had less modern values than their white peers, but Inuit scores varied considerably both within and among the 5 value orientations examined. Contains 34 references. (SV)

Function projective synchronization of memristor-based Cohen-Grossberg neural networks with time-varying delays.

PubMed

Abdurahman, Abdujelil; Jiang, Haijun; Rahman, Kaysar

2015-12-01

This paper deals with the problem of function projective synchronization for a class of memristor-based Cohen-Grossberg neural networks with time-varying delays. Based on the theory of differential equations with discontinuous right-hand side, some novel criteria are obtained to realize the function projective synchronization of addressed networks by combining open loop control and linear feedback control. As some special cases, several control strategies are given to ensure the realization of complete synchronization, anti-synchronization and the stabilization of the considered memristor-based Cohen-Grossberg neural network. Finally, a numerical example and its simulations are provided to demonstrate the effectiveness of the obtained results.

Use of Different Proteases to Obtain Flaxseed Protein Hydrolysates with Antioxidant Activity.

PubMed

Karamać, Magdalena; Kosińska-Cagnazzo, Agnieszka; Kulczyk, Anna

2016-06-29

The antioxidant activity of flaxseed protein hydrolysates obtained using five different enzymes was evaluated. Proteins were isolated from flaxseed cake and were separately treated with papain, trypsin, pancreatin, Alcalase and Flavourzyme. The degree of hydrolysis (DH) was determined as the percentage of cleaved peptide bonds using a spectrophotometric method with o-phthaldialdehyde. The distribution of the molecular weights (MW) of the hydrolysis products was profiled using Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (Tricine-SDS-PAGE) and size exclusion-high performance liquid chromatography (SE-HPLC) separations. The antioxidant activities of the protein isolate and hydrolysates were probed for their radical scavenging activity using 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonate) radical cation (ABTS(•+)) and photochemiluminescence (PCL-ACL) assays, and for their ferric reducing antioxidant power (FRAP) and ability to bind Fe(2+). The hydrolysates were more effective as antioxidants than the protein isolate in all systems. The PCL-ACL values of the hydrolysates ranged from 7.2 to 35.7 μmol Trolox/g. Both the FRAP and ABTS(•+) scavenging activity differed among the hydrolysates to a lower extent, with the ranges of 0.20-0.24 mmol Fe(2+)/g and 0.17-0.22 mmol Trolox/g, respectively. The highest chelating activity (71.5%) was noted for the pancreatin hydrolysate. In general, the hydrolysates obtained using Alcalase and pancreatin had the highest antioxidant activity, even though their DH (15.4% and 29.3%, respectively) and the MW profiles of the peptides varied substantially. The O₂(•-) scavenging activity and the ability to chelate Fe(2+) of the Flavourzyme hydrolysate were lower than those of the Alcalase and pancreatin hydrolysates. Papain was the least effective in releasing the peptides with antioxidant activity. The study showed that the type of enzyme used for flaxseed protein hydrolysis determines the antioxidant activity

Costs and added value of haemodialysis and peritoneal dialysis outsourcing agreements.

PubMed

Lamas Barreiro, J M; Alonso Suárez, M; Saavedra Alonso, J A; Gándara Martínez, A

2011-01-01

Despite the discrepancy in results from Spanish studies on the costs of dialysis, it is assumed that peritoneal dialysis (PD) is more efficient than haemodialysis (HD). To analyse the costs and added value of HD and PD outsourcing agreements in Galicia, the medical transport for HD and the relationship between the cost of the agreement and the cost of consumables used in continuous ambulatory peritoneal dialysis (CAPD) with bicarbonate. The cost of the outsourcing agreements and the staff was obtained from official publications. The cost of PD and medical transport were calculated using health service data for one month and extrapolating it to one year. The cost of CAPD consumables was provided by the suppliers. The added value was calculated from the investments generated for each agreement treating 40 patients. Expressed as patient/year, the mean costs for treatment were €21595 and €25664 in HD and PD, respectively. Medical transport varied between €3323 and €6338, while those of the CAPD agreement and consumables were €19268 and €12057, respectively. The added value was greater with the HD agreement, especially considering the jobs created. One cannot generalise that the cost of PD, which is significantly influenced by prescriptions, is lower than that of HD. It would be appropriate to review the additional cost to consumables in the CAPD agreement. The added value generated by dialysis agreements should be considered in future studies and in health planning. More controlled studies are needed to better understand this issue.

Einstein Equations from Varying Complexity

NASA Astrophysics Data System (ADS)

Czech, Bartłomiej

2018-01-01

A recent proposal equates the circuit complexity of a quantum gravity state with the gravitational action of a certain patch of spacetime. Since Einstein's equations follow from varying the action, it should be possible to derive them by varying complexity. I present such a derivation for vacuum solutions of pure Einstein gravity in three-dimensional asymptotically anti-de Sitter space. The argument relies on known facts about holography and on properties of tensor network renormalization, an algorithm for coarse-graining (and optimizing) tensor networks.

Use of the 'real-ear to dial difference' to derive real-ear SPL from hearing level obtained with insert earphones.

PubMed

Munro, K J; Lazenby, A

2001-10-01

The electroacoustic characteristics of a hearing instrument are normally selected for individuals using data obtained during audiological assessment. The precise inter-relationship between the electroacoustic and audiometric variables is most readily appreciated when they have been measured at the same reference point, such as the tympanic membrane. However, it is not always possible to obtain the real-ear sound pressure level (SPL) directly if this is below the noise floor of the probe-tube microphone system or if the subject is unco-operative. The real-ear SPL may be derived by adding the subject's real-ear to dial difference (REDD) acoustic transform to the audiometer dial setting. The aim of the present study was to confirm the validity of the Audioscan RM500 to measure the REDD with the ER-3A insert earphone. A probe-tube microphone was used to measure the real-ear SPL and REDD from the right ears of 16 adult subjects ranging in age from 22 to 41 years (mean age 27 years). Measurements were made from 0.25 kHz to 6 kHz at a dial setting of 70 dB with an ER-3A insert earphone and two earmould configurations: the EAR-LINK foam ear-tip and the subjects' customized skeleton earmoulds. Mean REDD varied as a function of frequency but was typically approximately 12 dB with a standard deviation (SD) of +/- 1.7 dB and +/- 2.7 dB for the foam ear-tip and customized earmould, respectively. The mean test-retest difference of the REDD varied with frequency but was typically 0.5 dB (SD 1 dB). Over the frequency range 0.5-4 kHz, the derived values were found to be within 5 dB of the measured values in 95% of subjects when using the EAR-LINK foam ear-tip and within 4 dB when using the skeleton earmould. The individually measured REDD transform can be used in clinical practice to derive a valid estimate of real-ear SPL when it has not been possible to measure this directly.

12 CFR 703.11 - Valuing securities.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) At least monthly, a Federal credit union must determine the fair value of each security it holds. It may determine fair value by obtaining a price quotation on the security from an industry-recognized... supervisory committee or its external auditor must independently assess the reliability of monthly price...

Nonlinear recurrent neural networks for finite-time solution of general time-varying linear matrix equations.

PubMed

Xiao, Lin; Liao, Bolin; Li, Shuai; Chen, Ke

2018-02-01

In order to solve general time-varying linear matrix equations (LMEs) more efficiently, this paper proposes two nonlinear recurrent neural networks based on two nonlinear activation functions. According to Lyapunov theory, such two nonlinear recurrent neural networks are proved to be convergent within finite-time. Besides, by solving differential equation, the upper bounds of the finite convergence time are determined analytically. Compared with existing recurrent neural networks, the proposed two nonlinear recurrent neural networks have a better convergence property (i.e., the upper bound is lower), and thus the accurate solutions of general time-varying LMEs can be obtained with less time. At last, various different situations have been considered by setting different coefficient matrices of general time-varying LMEs and a great variety of computer simulations (including the application to robot manipulators) have been conducted to validate the better finite-time convergence of the proposed two nonlinear recurrent neural networks. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fractal analysis of time varying data

DOEpatents

Vo-Dinh, Tuan; Sadana, Ajit

2002-01-01

Characteristics of time varying data, such as an electrical signal, are analyzed by converting the data from a temporal domain into a spatial domain pattern. Fractal analysis is performed on the spatial domain pattern, thereby producing a fractal dimension D.sub.F. The fractal dimension indicates the regularity of the time varying data.

Sensitivity of solar g-modes to varying G cosmologies

NASA Technical Reports Server (NTRS)

Guenther, D. B.; Sills, Ken; Demarque, Pierre; Krauss, Lawrence M.

1995-01-01

The sensitivity of the solar g-mode oscillation spectrum to variability in the universal gravitational constant G is described. Solar models in varying G cosmologies were constructed by evolving a zero-age main-sequence stellar model to the Sun's current age, while allowing the value of G to change according to the power law G(t) proportional to t(exp -beta), where Beta approximately equals delta G/GH and H is the Hubble constant. All solar models were constrained to the observed luminosity and radius at the current age of the Sun by adjusting the helium abundance and the mixing-length parameter of the models in the usual way for standard stellar models. Low-l g-mode oscillation periods were calculated for each of the models and compared to the claimed observation of the solar g-mode oscillation spectrum by Hill & Gu (1990). If one accepts Hill & Gu's claims, then within the uncertainties of the physics of the solar model calculation, our models rule out all but (delta G/GH) less than approximately 0.05. In other words, we conclude that G could not have varied by more than 2% over the past 4.5 Gyr, the lifetime of the present-day Sun. This result lends independent support to the validity of the standard solar model.

Evaluating Frameworks That Provide Value Measures for Health Care Interventions.

PubMed

Mandelblatt, Jeanne S; Ramsey, Scott D; Lieu, Tracy A; Phelps, Charles E

2017-02-01

The recent acceleration of scientific discovery has led to greater choices in health care. New technologies, diagnostic tests, and pharmaceuticals have widely varying impact on patients and populations in terms of benefits, toxicities, and costs, stimulating a resurgence of interest in the creation of frameworks intended to measure value in health. Many of these are offered by providers and/or advocacy organizations with expertise and interest in specific diseases (e.g., cancer and heart disease). To help assess the utility of and the potential biases embedded in these frameworks, we created an evaluation taxonomy with seven basic components: 1) define the purpose; 2) detail the conceptual approach, including perspectives, methods for obtaining preferences of decision makers (e.g., patients), and ability to incorporate multiple dimensions of value; 3) discuss inclusions and exclusions of elements included in the framework, and whether the framework assumes clinical intervention or offers alternatives such as palliative care or watchful waiting; 4) evaluate data sources and their scientific validity; 5) assess the intervention's effect on total costs of treating a defined population; 6) analyze how uncertainty is incorporated; and 7) illuminate possible conflicts of interest among those creating the framework. We apply the taxonomy to four representative value frameworks recently published by professional organizations focused on treatment of cancer and heart disease and on vaccine use. We conclude that each of these efforts has strengths and weaknesses when evaluated using our taxonomy, and suggest pathways to enhance the utility of value-assessing frameworks for policy and clinical decision making. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

In vivo precision of conventional and digital methods for obtaining quadrant dental impressions.

PubMed

Ender, Andreas; Zimmermann, Moritz; Attin, Thomas; Mehl, Albert

2016-09-01

Quadrant impressions are commonly used as alternative to full-arch impressions. Digital impression systems provide the ability to take these impressions very quickly; however, few studies have investigated the accuracy of the technique in vivo. The aim of this study is to assess the precision of digital quadrant impressions in vivo in comparison to conventional impression techniques. Impressions were obtained via two conventional (metal full-arch tray, CI, and triple tray, T-Tray) and seven digital impression systems (Lava True Definition Scanner, T-Def; Lava Chairside Oral Scanner, COS; Cadent iTero, ITE; 3Shape Trios, TRI; 3Shape Trios Color, TRC; CEREC Bluecam, Software 4.0, BC4.0; CEREC Bluecam, Software 4.2, BC4.2; and CEREC Omnicam, OC). Impressions were taken three times for each of five subjects (n = 15). The impressions were then superimposed within the test groups. Differences from model surfaces were measured using a normal surface distance method. Precision was calculated using the Perc90_10 value. The values for all test groups were statistically compared. The precision ranged from 18.8 (CI) to 58.5 μm (T-Tray), with the highest precision in the CI, T-Def, BC4.0, TRC, and TRI groups. The deviation pattern varied distinctly depending on the impression method. Impression systems with single-shot capture exhibited greater deviations at the tooth surface whereas high-frame rate impression systems differed more in gingival areas. Triple tray impressions displayed higher local deviation at the occlusal contact areas of upper and lower jaw. Digital quadrant impression methods achieve a level of precision, comparable to conventional impression techniques. However, there are significant differences in terms of absolute values and deviation pattern. With all tested digital impression systems, time efficient capturing of quadrant impressions is possible. The clinical precision of digital quadrant impression models is sufficient to cover a broad variety of

THE VARIED INFLUENCE OF SES ON ENVIRONMENTAL CONCERN

PubMed Central

Pampel, Fred C.

2013-01-01

Objective Cross-national studies have found positive relationships of socioeconomic status (SES) with environmental concern at the individual level but have not systematically examined how the relationships may differ across nations. Such comparisons have relevance to identifying the generality of theories of postmaterialism, affluence, and global environmentalism. Methods This study specifies how the individual-level influence of SES varies across national contexts and tests predictions using four waves of the World Values Survey on up to 96 nations. Results The results show that SES is associated only weakly with environmental concern in lower income nations with poor environmental conditions but is associated strongly and positively in higher income nations with better environmental conditions. Conclusion SES has a contingent relationship with environmental concern such that the global environmentalism theory receives support for lower income nations, while the postmaterialism and affluence theories receive support for higher income nations. PMID:24678128

Lunar tidal acceleration obtained from satellite-derived ocean tide parameters

NASA Technical Reports Server (NTRS)

Goad, C. C.; Douglas, B. C.

1978-01-01

One hundred sets of mean elements of GEOS-3 computed at 2-day intervals yielded observation equations for the M sub 2 ocean tide from the long periodic variations of the inclination and node of the orbit. The 2nd degree Love number was given the value k sub 2 = 0.30 and the solid tide phase angle was taken to be zero. Combining obtained equations with results for the satellite 1967-92A gives the M sub 2 ocean tide parameter values. Under the same assumption of zero solid tide phase lag, the lunar tidal acceleration was found mostly due to the C sub 22 term in the expansion of the M sub 2 tide with additional small contributions from the 0 sub 1 and N sub 2 tides. Using Lambeck's (1975) estimates for the latter, the obtained acceleration in lunar longitudal in excellent agreement with the most recent determinations from ancient and modern astronomical data.

Scale effects on spatially varying relationships between urban landscape patterns and water quality.

PubMed

Sun, Yanwei; Guo, Qinghai; Liu, Jian; Wang, Run

2014-08-01

Scientific interpretation of the relationships between urban landscape patterns and water quality is important for sustainable urban planning and watershed environmental protection. This study applied the ordinary least squares regression model and the geographically weighted regression model to examine the spatially varying relationships between 12 explanatory variables (including three topographical factors, four land use parameters, and five landscape metrics) and 15 water quality indicators in watersheds of Yundang Lake, Maluan Bay, and Xinglin Bay with varying levels of urbanization in Xiamen City, China. A local and global investigation was carried out at the watershed-level, with 50 and 200 m riparian buffer scales. This study found that topographical features and landscape metrics are the dominant factors of water quality, while land uses are too weak to be considered as a strong influential factor on water quality. Such statistical results may be related with the characteristics of land use compositions in our study area. Water quality variations in the 50 m buffer were dominated by topographical variables. The impact of landscape metrics on water quality gradually strengthen with expanding buffer zones. The strongest relationships are obtained in entire watersheds, rather than in 50 and 200 m buffer zones. Spatially varying relationships and effective buffer zones were verified in this study. Spatially varying relationships between explanatory variables and water quality parameters are more diversified and complex in less urbanized areas than in highly urbanized areas. This study hypothesizes that all these varying relationships may be attributed to the heterogeneity of landscape patterns in different urban regions. Adjustment of landscape patterns in an entire watershed should be the key measure to successfully improving urban lake water quality.

Obtaining of caffeine from Turkish tea fiber and stalk wastes.

PubMed

Gürü, M; Içen, H

2004-08-01

The aim of this study was to find a cheap method to obtain caffeine. Experiments were performed on fiber and stalk wastes of Turkish tea plants that had no economical value other than being used merely as low grade fuel and fodder. Tea stalks and fiber were obtained from tea factories. Parameters affecting caffeine extraction from tea wastes were determined to be, mixing rate, water/tea ratio, temperature, time and particle size. The maximum yields by dried mass from the tea fibers and stalks were 1.16% and 0.92%, respectively.

Modelling tourists arrival using time varying parameter

NASA Astrophysics Data System (ADS)

Suciptawati, P.; Sukarsa, K. G.; Kencana, Eka N.

2017-06-01

The importance of tourism and its related sectors to support economic development and poverty reduction in many countries increase researchers’ attentions to study and model tourists’ arrival. This work is aimed to demonstrate time varying parameter (TVP) technique to model the arrival of Korean’s tourists to Bali. The number of Korean tourists whom visiting Bali for period January 2010 to December 2015 were used to model the number of Korean’s tourists to Bali (KOR) as dependent variable. The predictors are the exchange rate of Won to IDR (WON), the inflation rate in Korea (INFKR), and the inflation rate in Indonesia (INFID). Observing tourists visit to Bali tend to fluctuate by their nationality, then the model was built by applying TVP and its parameters were approximated using Kalman Filter algorithm. The results showed all of predictor variables (WON, INFKR, INFID) significantly affect KOR. For in-sample and out-of-sample forecast with ARIMA’s forecasted values for the predictors, TVP model gave mean absolute percentage error (MAPE) as much as 11.24 percent and 12.86 percent, respectively.

Estimation of spatially varying heat transfer coefficient from a flat plate with flush mounted heat sources using Bayesian inference

NASA Astrophysics Data System (ADS)

Jakkareddy, Pradeep S.; Balaji, C.

2016-09-01

This paper employs the Bayesian based Metropolis Hasting - Markov Chain Monte Carlo algorithm to solve inverse heat transfer problem of determining the spatially varying heat transfer coefficient from a flat plate with flush mounted discrete heat sources with measured temperatures at the bottom of the plate. The Nusselt number is assumed to be of the form Nu = aReb(x/l)c . To input reasonable values of ’a’ and ‘b’ into the inverse problem, first limited two dimensional conjugate convection simulations were done with Comsol. Based on the guidance from this different values of ‘a’ and ‘b’ are input to a computationally less complex problem of conjugate conduction in the flat plate (15mm thickness) and temperature distributions at the bottom of the plate which is a more convenient location for measuring the temperatures without disturbing the flow were obtained. Since the goal of this work is to demonstrate the eficiacy of the Bayesian approach to accurately retrieve ‘a’ and ‘b’, numerically generated temperatures with known values of ‘a’ and ‘b’ are treated as ‘surrogate’ experimental data. The inverse problem is then solved by repeatedly using the forward solutions together with the MH-MCMC aprroach. To speed up the estimation, the forward model is replaced by an artificial neural network. The mean, maximum-a-posteriori and standard deviation of the estimated parameters ‘a’ and ‘b’ are reported. The robustness of the proposed method is examined, by synthetically adding noise to the temperatures.

Dual-user nonlinear teleoperation subjected to varying time delay and bounded inputs.

PubMed

Zakerimanesh, Amir; Hashemzadeh, Farzad; Ghiasi, Amir Rikhtehgar

2017-05-01

A novel trilateral control architecture for Dual-master/Single-slave teleoperation system with taking account of saturation in actuators, nonlinear dynamics for telemanipulators and bounded varying time delay which affects the transmitted signals in the communication channels, is proposed in this paper. In this research, we will address the stability and desired position coordination problem of trilateral teleoperation system by extension of (nP+D) controller that is used for Single-master/Single-slave teleoperation system. Our proposed controller is weighted summation of nonlinear Proportional plus Damping (nP+D) controller that incorporate gravity compensation and the weights are specified by the dominance factor, which determines the supremacy of each user over the slave robot and over the other user. The asymptotic stability of closed loop dynamics is studied using Lyapunov-Krasovskii functional under conditions on the controller parameters, the actuator saturation characteristics and the maximum values of varying time delays. It is shown that these controllers satisfy the desired position coordination problem in free motion condition. To show the effectiveness of the proposed method, a number of simulations have been conducted on a varying time delay Dual-master/Single-slave teleoperation system using 3-DOF planar robots for each telemanipulator subjected to actuator saturation. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

On the extreme value statistics of normal random matrices and 2D Coulomb gases: Universality and finite N corrections

NASA Astrophysics Data System (ADS)

Ebrahimi, R.; Zohren, S.

2018-03-01

In this paper we extend the orthogonal polynomials approach for extreme value calculations of Hermitian random matrices, developed by Nadal and Majumdar (J. Stat. Mech. P04001 arXiv:1102.0738), to normal random matrices and 2D Coulomb gases in general. Firstly, we show that this approach provides an alternative derivation of results in the literature. More precisely, we show convergence of the rescaled eigenvalue with largest modulus of a normal Gaussian ensemble to a Gumbel distribution, as well as universality for an arbitrary radially symmetric potential. Secondly, it is shown that this approach can be generalised to obtain convergence of the eigenvalue with smallest modulus and its universality for ring distributions. Most interestingly, the here presented techniques are used to compute all slowly varying finite N correction of the above distributions, which is important for practical applications, given the slow convergence. Another interesting aspect of this work is the fact that we can use standard techniques from Hermitian random matrices to obtain the extreme value statistics of non-Hermitian random matrices resembling the large N expansion used in context of the double scaling limit of Hermitian matrix models in string theory.

Partial Adaptation of Obtained and Observed Value Signals Preserves Information about Gains and Losses

PubMed Central

Baddeley, Michelle; Tobler, Philippe N.; Schultz, Wolfram

2016-01-01

Given that the range of rewarding and punishing outcomes of actions is large but neural coding capacity is limited, efficient processing of outcomes by the brain is necessary. One mechanism to increase efficiency is to rescale neural output to the range of outcomes expected in the current context, and process only experienced deviations from this expectation. However, this mechanism comes at the cost of not being able to discriminate between unexpectedly low losses when times are bad versus unexpectedly high gains when times are good. Thus, too much adaptation would result in disregarding information about the nature and absolute magnitude of outcomes, preventing learning about the longer-term value structure of the environment. Here we investigate the degree of adaptation in outcome coding brain regions in humans, for directly experienced outcomes and observed outcomes. We scanned participants while they performed a social learning task in gain and loss blocks. Multivariate pattern analysis showed two distinct networks of brain regions adapt to the most likely outcomes within a block. Frontostriatal areas adapted to directly experienced outcomes, whereas lateral frontal and temporoparietal regions adapted to observed social outcomes. Critically, in both cases, adaptation was incomplete and information about whether the outcomes arose in a gain block or a loss block was retained. Univariate analysis confirmed incomplete adaptive coding in these regions but also detected nonadapting outcome signals. Thus, although neural areas rescale their responses to outcomes for efficient coding, they adapt incompletely and keep track of the longer-term incentives available in the environment. SIGNIFICANCE STATEMENT Optimal value-based choice requires that the brain precisely and efficiently represents positive and negative outcomes. One way to increase efficiency is to adapt responding to the most likely outcomes in a given context. However, too strong adaptation would result

From Out Here: Valuing our Rural Colleges

ERIC Educational Resources Information Center

Geller, Jack M.

2004-01-01

There is little doubt that having a local college or university in your community is a wonderful local and regional asset. However, the true size and scope of its economic value and impact on the community can vary greatly. Is your community just thankful that as a large employer the college provides a large and stable payroll? Is the college…

Separate Populations of Neurons in Ventral Striatum Encode Value and Motivation

PubMed Central

Gentry, Ronny N.; Goldstein, Brandon L.; Hearn, Taylor N.; Barnett, Brian R.; Kashtelyan, Vadim; Roesch, Matthew R.

2013-01-01

Neurons in the ventral striatum (VS) fire to cues that predict differently valued rewards. It is unclear whether this activity represents the value associated with the expected reward or the level of motivation induced by reward anticipation. To distinguish between the two, we trained rats on a task in which we varied value independently from motivation by manipulating the size of the reward expected on correct trials and the threat of punishment expected upon errors. We found that separate populations of neurons in VS encode expected value and motivation. PMID:23724077

Working harder to obtain more snack foods when wanting to eat less.

PubMed

Giesen, Janneke C A H; Havermans, Remco C; Nederkoorn, Chantal; Strafaci, Silvana; Jansen, Anita

2009-01-01

This study investigates individual differences in the reinforcing value of snack food. More specifically, it was investigated whether differences in restraint status are associated with differences in working for high-caloric snack food. Thirty-six unrestrained non-dieters, twenty restrained non-dieters and fifteen current dieters performed a concurrent schedules task in which they had the option to work for points for either snack food or fruit and vegetables. By progressively increasing the "price" of the snack foods (i.e., the amount of work required to obtain extra snack points) the relative reinforcing value of snack food was determined. As hypothesized, restrained non-dieters worked harder and current dieters worked less hard to obtain snack food as compared to unrestrained non-dieters.

12 CFR 703.11 - Valuing securities.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 12 Banks and Banking 7 2014-01-01 2014-01-01 false Valuing securities. 703.11 Section 703.11 Banks... DEPOSIT ACTIVITIES § 703.11 Valuing securities. (a) Before purchasing or selling a security, a Federal credit union must obtain either price quotations on the security from at least two broker-dealers or a...

Effects of b-value and number of gradient directions on diffusion MRI measures obtained with Q-ball imaging

NASA Astrophysics Data System (ADS)

Schilling, Kurt G.; Nath, Vishwesh; Blaber, Justin; Harrigan, Robert L.; Ding, Zhaohua; Anderson, Adam W.; Landman, Bennett A.

2017-02-01

High-angular-resolution diffusion-weighted imaging (HARDI) MRI acquisitions have become common for use with higher order models of diffusion. Despite successes in resolving complex fiber configurations and probing microstructural properties of brain tissue, there is no common consensus on the optimal b-value and number of diffusion directions to use for these HARDI methods. While this question has been addressed by analysis of the diffusion-weighted signal directly, it is unclear how this translates to the information and metrics derived from the HARDI models themselves. Using a high angular resolution data set acquired at a range of b-values, and repeated 11 times on a single subject, we study how the b-value and number of diffusion directions impacts the reproducibility and precision of metrics derived from Q-ball imaging, a popular HARDI technique. We find that Q-ball metrics associated with tissue microstructure and white matter fiber orientation are sensitive to both the number of diffusion directions and the spherical harmonic representation of the Q-ball, and often are biased when under sampled. These results can advise researchers on appropriate acquisition and processing schemes, particularly when it comes to optimizing the number of diffusion directions needed for metrics derived from Q-ball imaging.

Nuclear DNA C‐values in 30 Species Double the Familial Representation in Pteridophytes

PubMed Central

OBERMAYER, RENATE; LEITCH, ILIA J.; HANSON, LYNDA; BENNETT, MICHAEL D.

2002-01-01

Nuclear DNA C‐values and genome size are important biodiversity characters with fundamental biological significance. Yet C‐value data for pteridophytes, a diverse group of vascular plants with approx. 9000 extant species, remain scarce. A recent survey by Bennett and Leitch (2001, Annals of Botany 87: 335–345) found that C‐values were reported for only 48 pteridophyte species. To improve phylogenetic representation in this group and to check previously reported estimates, C‐values for 30 taxa in 17 families were measured using flow cytometry for all but one species. This technique proved generally applicable, but the ease with which C‐value data were generated varied greatly between materials. Comparing the new data with those previously published revealed several large discrepancies. After discounting doubtful data, C‐values for 62 pteridophyte species remained acceptable for analysis. The present work has increased the number of such species’ C‐values by 93 %, and more than doubled the number of families represented (from 10 to 21). Analysis shows that pteridophyte C‐values vary approx. 450‐fold, from 0·16 pg in Selaginella kraussiana to 72·7 pg in Psilotum nudum var. gasa. Superimposing C‐value data onto a robust phylogeny of pteridophytes suggests some possible trends in C‐value evolution and highlights areas for future work. PMID:12197518

Optimizing Methods of Obtaining Stellar Parameters for the H3 Survey

NASA Astrophysics Data System (ADS)

Ivory, KeShawn; Conroy, Charlie; Cargile, Phillip

2018-01-01

The Stellar Halo at High Resolution with Hectochelle Survey (H3) is in the process of observing and collecting stellar parameters for stars in the Milky Way's halo. With a goal of measuring radial velocities for fainter stars, it is crucial that we have optimal methods of obtaining this and other parameters from the data from these stars.The method currently developed is The Payne, named after Cecilia Payne-Gaposchkin, a code that uses neural networks and Markov Chain Monte Carlo methods to utilize both spectra and photometry to obtain values for stellar parameters. This project was to investigate the benefit of fitting both spectra and spectral energy distributions (SED). Mock spectra using the parameters of the Sun were created and noise was inserted at various signal to noise values. The Payne then fit each mock spectrum with and without a mock SED also generated from solar parameters. The result was that at high signal to noise, the spectrum dominated and the effect of fitting the SED was minimal. But at low signal to noise, the addition of the SED greatly decreased the standard deviation of the data and resulted in more accurate values for temperature and metallicity.

Estimating the reliability of glycemic index values and potential sources of methodological and biological variability

USDA-ARS?s Scientific Manuscript database

Background: The utility of glycemic index (GI) values for chronic disease risk management remains controversial. While absolute GI value determinations for individual foods have been shown to vary significantly in individuals with diabetes, there is a dearth of data on the reliability of GI value de...

Failure Modes in Capacitors When Tested Under a Time-Varying Stress

NASA Technical Reports Server (NTRS)

Liu, David (Donhang)

2011-01-01

Power-on failure has been the prevalent failure mechanism for solid tantalum capacitors in decoupling applications. A surge step stress test (SSST) has been previously applied to identify the critical stress level of a capacitor batch to give some predictability to the power-on failure mechanism [1]. But SSST can also be viewed as an electrically destructive test under a time-varying stress (voltage). It consists of rapidly charging the capacitor with incremental voltage increases, through a low resistance in series, until the capacitor under test is electrically shorted. When the reliability of capacitors is evaluated, a highly accelerated life test (HALT) is usually adopted since it is a time-efficient method of determining the failure mechanism; however, a destructive test under a time-varying stress such as SSST is even more time efficient. It usually takes days or weeks to complete a HALT test, but it only takes minutes for a time-varying stress test to produce failures. The advantage of incorporating a specific time-varying stress profile into a statistical model is significant in providing an alternative life test method for quickly revealing the failure mechanism in capacitors. In this paper, a time-varying stress that mimics a typical SSST has been incorporated into the Weibull model to characterize the failure mechanism in different types of capacitors. The SSST circuit and transient conditions for correctly surge testing capacitors are discussed. Finally, the SSST was applied for testing Ta capacitors, polymer aluminum capacitors (PA capacitors), and multi-layer ceramic (MLC) capacitors with both precious metal electrodes (PME) and base metal electrodes (BME). The test results are found to be directly associated with the dielectric layer breakdown in Ta and PA capacitors and are independent of the capacitor values, the way the capacitors were built, and the capacitors manufacturers. The test results also show that MLC capacitors exhibit surge breakdown

Fast Time-Varying Volume Rendering Using Time-Space Partition (TSP) Tree

NASA Technical Reports Server (NTRS)

Shen, Han-Wei; Chiang, Ling-Jen; Ma, Kwan-Liu

1999-01-01

We present a new, algorithm for rapid rendering of time-varying volumes. A new hierarchical data structure that is capable of capturing both the temporal and the spatial coherence is proposed. Conventional hierarchical data structures such as octrees are effective in characterizing the homogeneity of the field values existing in the spatial domain. However, when treating time merely as another dimension for a time-varying field, difficulties frequently arise due to the discrepancy between the field's spatial and temporal resolutions. In addition, treating spatial and temporal dimensions equally often prevents the possibility of detecting the coherence that is unique in the temporal domain. Using the proposed data structure, our algorithm can meet the following goals. First, both spatial and temporal coherence are identified and exploited for accelerating the rendering process. Second, our algorithm allows the user to supply the desired error tolerances at run time for the purpose of image-quality/rendering-speed trade-off. Third, the amount of data that are required to be loaded into main memory is reduced, and thus the I/O overhead is minimized. This low I/O overhead makes our algorithm suitable for out-of-core applications.

Removal of mercury (II) from aqueous solution by activated carbon obtained from furfural.

PubMed

Yardim, M F; Budinova, T; Ekinci, E; Petrov, N; Razvigorova, M; Minkova, V

2003-08-01

The adsorption of Hg(II) from aqueous solution at 293 K by activated carbon obtained from furfural is studied. The carbon is prepared by polymerization of furfural following carbonization and activation of the obtained polymer material with water vapor at 800 degrees C. Adsorption studies of Hg(II) are carried out varying some conditions: treatment time, metal ion concentration, adsorbent amount and pH. It is determined that Hg(II) adsorption follows both Langmuir and Freundlich isotherms. The adsorption capacity of the carbon is 174 mg/g. It is determined that Hg(II) uptake increases with increasing pH. Desorption studies are performed with hot water. The percent recovery of Hg(II) is 6%.

Optimization of the parameters for obtaining zirconia-alumina coatings, made by flame spraying from results of numerical simulation

NASA Astrophysics Data System (ADS)

Ferrer, M.; Vargas, F.; Peña, G.

2017-12-01

The K-Sommerfeld values (K) and the melting percentage (% F) obtained by numerical simulation using the Jets et Poudres software were used to find the projection parameters of zirconia-alumina coatings by thermal spraying flame, in order to obtain coatings with good morphological and structural properties to be used as thermal insulation. The experimental results show the relationship between the Sommerfeld parameter and the porosity of the zirconia-alumina coatings. It is found that the lowest porosity is obtained when the K-Sommerfeld value is close to 45 with an oxidant flame, on the contrary, when superoxidant flames are used K values are close 52, which improve wear resistance.

Design of 2D time-varying vector fields.

PubMed

Chen, Guoning; Kwatra, Vivek; Wei, Li-Yi; Hansen, Charles D; Zhang, Eugene

2012-10-01

Design of time-varying vector fields, i.e., vector fields that can change over time, has a wide variety of important applications in computer graphics. Existing vector field design techniques do not address time-varying vector fields. In this paper, we present a framework for the design of time-varying vector fields, both for planar domains as well as manifold surfaces. Our system supports the creation and modification of various time-varying vector fields with desired spatial and temporal characteristics through several design metaphors, including streamlines, pathlines, singularity paths, and bifurcations. These design metaphors are integrated into an element-based design to generate the time-varying vector fields via a sequence of basis field summations or spatial constrained optimizations at the sampled times. The key-frame design and field deformation are also introduced to support other user design scenarios. Accordingly, a spatial-temporal constrained optimization and the time-varying transformation are employed to generate the desired fields for these two design scenarios, respectively. We apply the time-varying vector fields generated using our design system to a number of important computer graphics applications that require controllable dynamic effects, such as evolving surface appearance, dynamic scene design, steerable crowd movement, and painterly animation. Many of these are difficult or impossible to achieve via prior simulation-based methods. In these applications, the time-varying vector fields have been applied as either orientation fields or advection fields to control the instantaneous appearance or evolving trajectories of the dynamic effects.

Using Value-Added Measures of Teacher Quality. Brief 9

ERIC Educational Resources Information Center

Hanushek, Eric A.; Rivkin, Steven G.

2010-01-01

Extensive education research on the contribution of teachers to student achievement produces two generally accepted results. First, teacher quality varies substantially as measured by the value added to student achievement or future academic attainment or earnings. Second, variables often used to determine entry into the profession and…

An evaluation of the accuracy of geomagnetic data obtained from an unattended, automated, quasi-absolute station

USGS Publications Warehouse

Herzog, D.C.

1990-01-01

A comparison is made of geomagnetic calibration data obtained from a high-sensitivity proton magnetometer enclosed within an orthogonal bias coil system, with data obtained from standard procedures at a mid-latitude U.S. Geological Survey magnetic observatory using a quartz horizontal magnetometer, a Ruska magnetometer, and a total field magnetometer. The orthogonal coil arrangement is used with the proton magnetometer to provide Deflected-Inclination-Deflected-Declination (DIDD) data from which quasi-absolute values of declination, horizontal intensity, and vertical intensity can be derived. Vector magnetometers provide the ordinate values to yield baseline calibrations for both the DIDD and standard observatory processes. Results obtained from a prototype system over a period of several months indicate that the DIDD unit can furnish adequate absolute field values for maintaining observatory calibration data, thus providing baseline control for unattended, remote stations. ?? 1990.

Stochastic analysis of epidemics on adaptive time varying networks

NASA Astrophysics Data System (ADS)

Kotnis, Bhushan; Kuri, Joy

2013-06-01

Many studies investigating the effect of human social connectivity structures (networks) and human behavioral adaptations on the spread of infectious diseases have assumed either a static connectivity structure or a network which adapts itself in response to the epidemic (adaptive networks). However, human social connections are inherently dynamic or time varying. Furthermore, the spread of many infectious diseases occur on a time scale comparable to the time scale of the evolving network structure. Here we aim to quantify the effect of human behavioral adaptations on the spread of asymptomatic infectious diseases on time varying networks. We perform a full stochastic analysis using a continuous time Markov chain approach for calculating the outbreak probability, mean epidemic duration, epidemic reemergence probability, etc. Additionally, we use mean-field theory for calculating epidemic thresholds. Theoretical predictions are verified using extensive simulations. Our studies have uncovered the existence of an “adaptive threshold,” i.e., when the ratio of susceptibility (or infectivity) rate to recovery rate is below the threshold value, adaptive behavior can prevent the epidemic. However, if it is above the threshold, no amount of behavioral adaptations can prevent the epidemic. Our analyses suggest that the interaction patterns of the infected population play a major role in sustaining the epidemic. Our results have implications on epidemic containment policies, as awareness campaigns and human behavioral responses can be effective only if the interaction levels of the infected populace are kept in check.

Pinning synchronization of memristor-based neural networks with time-varying delays.

PubMed

Yang, Zhanyu; Luo, Biao; Liu, Derong; Li, Yueheng

2017-09-01

In this paper, the synchronization of memristor-based neural networks with time-varying delays via pinning control is investigated. A novel pinning method is introduced to synchronize two memristor-based neural networks which denote drive system and response system, respectively. The dynamics are studied by theories of differential inclusions and nonsmooth analysis. In addition, some sufficient conditions are derived to guarantee asymptotic synchronization and exponential synchronization of memristor-based neural networks via the presented pinning control. Furthermore, some improvements about the proposed control method are also discussed in this paper. Finally, the effectiveness of the obtained results is demonstrated by numerical simulations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Visual and Statistical Analysis of Digital Elevation Models Generated Using Idw Interpolator with Varying Powers

NASA Astrophysics Data System (ADS)

Asal, F. F.

2012-07-01

Digital elevation data obtained from different Engineering Surveying techniques is utilized in generating Digital Elevation Model (DEM), which is employed in many Engineering and Environmental applications. This data is usually in discrete point format making it necessary to utilize an interpolation approach for the creation of DEM. Quality assessment of the DEM is a vital issue controlling its use in different applications; however this assessment relies heavily on statistical methods with neglecting the visual methods. The research applies visual analysis investigation on DEMs generated using IDW interpolator of varying powers in order to examine their potential in the assessment of the effects of the variation of the IDW power on the quality of the DEMs. Real elevation data has been collected from field using total station instrument in a corrugated terrain. DEMs have been generated from the data at a unified cell size using IDW interpolator with power values ranging from one to ten. Visual analysis has been undertaken using 2D and 3D views of the DEM; in addition, statistical analysis has been performed for assessment of the validity of the visual techniques in doing such analysis. Visual analysis has shown that smoothing of the DEM decreases with the increase in the power value till the power of four; however, increasing the power more than four does not leave noticeable changes on 2D and 3D views of the DEM. The statistical analysis has supported these results where the value of the Standard Deviation (SD) of the DEM has increased with increasing the power. More specifically, changing the power from one to two has produced 36% of the total increase (the increase in SD due to changing the power from one to ten) in SD and changing to the powers of three and four has given 60% and 75% respectively. This refers to decrease in DEM smoothing with the increase in the power of the IDW. The study also has shown that applying visual methods supported by statistical

Neural-Dynamic-Method-Based Dual-Arm CMG Scheme With Time-Varying Constraints Applied to Humanoid Robots.

PubMed

Zhang, Zhijun; Li, Zhijun; Zhang, Yunong; Luo, Yamei; Li, Yuanqing

2015-12-01

We propose a dual-arm cyclic-motion-generation (DACMG) scheme by a neural-dynamic method, which can remedy the joint-angle-drift phenomenon of a humanoid robot. In particular, according to a neural-dynamic design method, first, a cyclic-motion performance index is exploited and applied. This cyclic-motion performance index is then integrated into a quadratic programming (QP)-type scheme with time-varying constraints, called the time-varying-constrained DACMG (TVC-DACMG) scheme. The scheme includes the kinematic motion equations of two arms and the time-varying joint limits. The scheme can not only generate the cyclic motion of two arms for a humanoid robot but also control the arms to move to the desired position. In addition, the scheme considers the physical limit avoidance. To solve the QP problem, a recurrent neural network is presented and used to obtain the optimal solutions. Computer simulations and physical experiments demonstrate the effectiveness and the accuracy of such a TVC-DACMG scheme and the neural network solver.

Suitability of Spatial Interpolation Techniques in Varying Aquifer Systems of a Basaltic Terrain for Monitoring Groundwater Availability

NASA Astrophysics Data System (ADS)

Katpatal, Y. B.; Paranjpe, S. V.; Kadu, M. S.

2017-12-01

Geological formations act as aquifer systems and variability in the hydrological properties of aquifers have control over groundwater occurrence and dynamics. To understand the groundwater availability in any terrain, spatial interpolation techniques are widely used. It has been observed that, with varying hydrogeological conditions, even in a geologically homogenous set up, there are large variations in observed groundwater levels. Hence, the accuracy of groundwater estimation depends on the use of appropriate interpretation techniques. The study area of the present study is Venna Basin of Maharashtra State, India which is a basaltic terrain with four different types of basaltic layers laid down horizontally; weathered vesicular basalt, weathered and fractured basalt, highly weathered unclassified basalt and hard massive basalt. The groundwater levels vary with topography as different types of basalts are present at varying depths. The local stratigraphic profiles were generated at different types of basaltic terrains. The present study aims to interpolate the groundwater levels within the basin and to check the co-relation between the estimated and the observed values. The groundwater levels for 125 observation wells situated in these different basaltic terrains for 20 years (1995 - 2015) have been used in the study. The interpolation was carried out in Geographical Information System (GIS) using ordinary kriging and Inverse Distance Weight (IDW) method. A comparative analysis of the interpolated values of groundwater levels is carried out for validating the recorded groundwater level dataset. The results were co-related to various types of basaltic terrains present in basin forming the aquifer systems. Mean Error (ME) and Mean Square Errors (MSE) have been computed and compared. It was observed that within the interpolated values, a good correlation does not exist between the two interpolation methods used. The study concludes that in crystalline basaltic

Flow in curved ducts of varying cross-section

NASA Astrophysics Data System (ADS)

Sotiropoulos, F.; Patel, V. C.

1992-07-01

Two numerical methods for solving the incompressible Navier-Stokes equations are compared with each other by applying them to calculate laminar and turbulent flows through curved ducts of regular cross-section. Detailed comparisons, between the computed solutions and experimental data, are carried out in order to validate the two methods and to identify their relative merits and disadvantages. Based on the conclusions of this comparative study a numerical method is developed for simulating viscous flows through curved ducts of varying cross-sections. The proposed method is capable of simulating the near-wall turbulence using fine computational meshes across the sublayer in conjunction with a two-layer k-epsilon model. Numerical solutions are obtained for: (1) a straight transition duct geometry, and (2) a hydroturbine draft-tube configuration at model scale Reynolds number for various inlet swirl intensities. The report also provides a detailed literature survey that summarizes all the experimental and computational work in the area of duct flows.

Carbon Dioxide Compensation Values in Citronella and Lemongrass 1

PubMed Central

Herath, H. M. Walter; Ormrod, Douglas P.

1977-01-01

Carbon dioxide compensation values of mature leaves from 10 selections of citronella (Cymbopogon nardus [L.] Rendle) grown at 32/27 or 27/21 C day/night temperatures and three strains of lemongrass (Cymbopogon citratus [D.C.] Stapf. and Cymbopogon flexuosus [D.C.] Stapf.) grown at 8- or 15-hour photoperiods were measured in a controlled environment at 25 C. All leaves had low compensation values but citronella varied from 1.3 to 9.7 μl/liter and lemongrass from 0.7 to 3.5 μl/liter. Lower growing temperature generally resulted in lower compensation values for citronella but there was no consistent photoperiod effect on lemongrass. PMID:16659935

Synthesis and characterization of microporous titanosilicate ETS-10 obtained with different Ti sources

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

Casado, Clara; Amghouz, Zakariae; Garcia, Jose R.

2009-06-03

Titanosilicate ETS-10 crystals were prepared by hydrothermal synthesis varying Ti source (TiCl{sub 3} and commercial TiO{sub 2}-anatase), time in autoclave and seeding with previously prepared ETS-10 crystals. The crystalline powders were characterized by X-ray diffraction, N{sub 2} adsorption, thermogravimetric analysis, and scanning and transmission electron microscopies. Control of the particle size of ETS-10 crystals ranging from 0.32 {mu}m x 0.41 {mu}m to 16.4 {mu}m x 32.5 {mu}m was successfully achieved varying the seeding and synthesis conditions. In particular, it was found that the use of TiO{sub 2}-anatase alone or together with TiCl{sub 3} promotes heterogeneous primary nucleation. Transmission electron microscopymore » demonstrated that the largest crystals obtained here were twinned.« less

Species Identification and Design Value Estimation of Wooden Members in Covered Bridges

Treesearch

Alex C. Wiedenhoeft; David E. Kretschmann

2014-01-01

Covered timber bridges are historic structures with unique aesthetic value. To preserve this value and maintain bridges in service, robust evaluation of their performance and safety is necessary. The strength of the timber found in covered bridges can vary considerably, not only because of age and condition, but also because of species and grade. For the practicing...

Rimonabant reduces the essential value of food in the genetically obese Zucker rat: an exponential demand analysis.

PubMed

Rasmussen, Erin B; Reilly, William; Buckley, Jessica; Boomhower, Steven R

2012-02-01

Research on free-food intake suggests that cannabinoids are implicated in the regulation of feeding. Few studies, however, have characterized how environmental factors that affect food procurement interact with cannabinoid drugs that reduce food intake. Demand analysis provides a framework to understand how cannabinoid blockers, such as rimonabant, interact with effort in reducing demand for food. The present study examined the effects rimonabant had on demand for sucrose in obese Zucker rats when effort to obtain food varied and characterized the data using the exponential ("essential value") model of demand. Twenty-nine male (15 lean, 14 obese) Zucker rats lever-pressed under eight fixed ratio (FR) schedules of sucrose reinforcement, in which the number of lever-presses to gain access to a single sucrose pellet varied between 1 and 300. After behavior stabilized under each FR schedule, acute doses of rimonabant (1-10mg/kg) were administered prior to some sessions. The number of food reinforcers and responses in each condition was averaged and the exponential and linear demand equations were fit to the data. These demand equations quantify the value of a reinforcer by its sensitivity to price (FR) increases. Under vehicle conditions, obese Zucker rats consumed more sucrose pellets than leans at smaller fixed ratios; however, they were equally sensitive to price increases with both models of demand. Rimonabant dose-dependently reduced reinforcers and responses for lean and obese rats across all FR schedules. Data from the exponential analysis suggest that rimonabant dose-dependently increased elasticity, i.e., reduced the essential value of sucrose, a finding that is consistent with graphical depictions of normalized demand curves. Copyright © 2011 Elsevier Inc. All rights reserved.

Employee-Organization Pro-environmental Values Fit and Pro-environmental Behavior: The Role of Supervisors' Personal Values.

PubMed

Lu, Hui; Liu, Xia; Chen, Hong; Long, Ruyin

2017-12-18

This study examines the relationship among the employees-organization pro-environmental values fit (E-O PEVs fit), supervisors' PEVs and employees' pro-environmental behaviors (PEB). Informed by the PEB, organizational values and employee-organization fit literature, we propose and test hypotheses that under egoistic, altruistic and biosphere-value orientations, E-O PEVs fit versus non-fit have significant effects on employees' private-sphere PEB and public-sphere PEB, identifying supervisors' PEVs as a moderator. An empirical investigation indicates that the effect of E-O PEVs fit on employees' private-sphere PEB and public-sphere PEB varies as the value orientation differs. More specifically, under the context of altruistic and biosphere-value orientations, if the organizational PEVs do not match the employees' PEVs, especially when the former exceeds the latter, employees' PEB will rise as the organizational PEVs increase. As for egoistic value orientation, when organizational PEVs exceed employees' PEVs, not only will public-sphere PEB stop decreasing and tend to stabilize, but also private-sphere PEB will rise to a slight degree. Furthermore, compared with altruistic and biospheric values dimensions, supervisors who promote egoistic PEVs will have a more significant effect on the relationship between global E-O PEVs fit and employees' PEB. Finally, we suggest that the goals of an organization and its supervisors need to be combined within the actual situation of Chinese corporations to truly implement corporate green practices by balancing the profit goal and the environmental goal.

Controlling orbital angular momentum of an optical vortex by varying its ellipticity

NASA Astrophysics Data System (ADS)

Kotlyar, Victor V.; Kovalev, Alexey A.

2018-03-01

An exact analytical expression is obtained for the orbital angular momentum (OAM) of a Gaussian optical vortex with a different degree of ellipticity. The OAM turned out to be proportional to the ratio of two Legendre polynomials of adjoining orders. It is shown that if an elliptical optical vortex is embedded into the center of the waist of a circularly symmetrical Gaussian beam, then the normalized OAM of such laser beam is fractional and it does not exceed the topological charge n. If, on the contrary, a circularly symmetrical optical vortex is embedded into the center of the waist of an elliptical Gaussian beam, then the OAM is equal to n. If the optical vortex and the Gaussian beam have the same (or matched) ellipticity degree, then the OAM of the laser beam is greater than n. Continuous varying of the OAM of a laser beam by varying its ellipticity degree can be used in optical trapping for accelerated motion of microscopic particles along an elliptical trajectory as well as in quantum informatics for detecting OAM-entangled photons.

Values exchange: using online technology to raise awareness of values and ethics in radiography education.

PubMed

Mc Inerney, John; Lees, Amanda

2018-03-01

Ethics and values are increasingly significant aspects of patient-centred healthcare. While it is widely agreed that ethics and values are essential for healthcare delivery, there is also an acknowledgement that these are areas that are challenging to teach. The purpose of this study is to report a small-scale evaluative research project of a web-based technology with the educational potential to facilitate learning in relation to ethics, values, self-reflection and peer-based learning. Five diagnostic radiography students took part in a semi-structured focus group with the aim of exploring their experiences of using Values Exchange, an online ethical decision-making framework, to examine practice-based ethical issues. Transcripts were interrogated for key themes. From the thematic analysis three major themes emerged, understanding and appreciating others, addressing the theory-practice gap and delivering a safe and effective learning environment. Perceived limitations of the platform included students' fear of misinterpreted responses and possibility of poor group dynamics. There are varied approaches to how ethics and values are taught and assessed within health-related environments. Values Exchange is one such teaching tool and has been investigated and described positively by radiography students in this study. Online teaching tools can have a positive effect in helping students identify their own values but require skilled implementation to reap positive rewards. © 2018 The Authors. Journal of Medical Radiation Sciences published by John Wiley & Sons Australia, Ltd on behalf of Australian Society of Medical Imaging and Radiation Therapy and New Zealand Institute of Medical Radiation Technology.

FLUID: A numerical interpolation procedure for obtaining thermodynamic and transport properties of fluids

NASA Technical Reports Server (NTRS)

Fessler, T. E.

1977-01-01

A computer program subroutine, FLUID, was developed to calculate thermodynamic and transport properties of pure fluid substances. It provides for determining the thermodynamic state from assigned values for temperature-density, pressure-density, temperature-pressure, pressure-entropy, or pressure-enthalpy. Liquid or two-phase (liquid-gas) conditions are considered as well as the gas phase. A van der Waals model is used to obtain approximate state values; these values are then corrected for real gas effects by model-correction factors obtained from tables based on experimental data. Saturation conditions, specific heat, entropy, and enthalpy data are included in the tables for each gas. Since these tables are external to the FLUID subroutine itself, FLUID can implement any gas for which a set of tables has been generated. (A setup phase is used to establish pointers dynamically to the tables for a specific gas.) Data-table preparation is described. FLUID is available in both SFTRAN and FORTRAN

Time varying voltage combustion control and diagnostics sensor

DOEpatents

Chorpening, Benjamin T [Morgantown, WV; Thornton, Jimmy D [Morgantown, WV; Huckaby, E David [Morgantown, WV; Fincham, William [Fairmont, WV

2011-04-19

A time-varying voltage is applied to an electrode, or a pair of electrodes, of a sensor installed in a fuel nozzle disposed adjacent the combustion zone of a continuous combustion system, such as of the gas turbine engine type. The time-varying voltage induces a time-varying current in the flame which is measured and used to determine flame capacitance using AC electrical circuit analysis. Flame capacitance is used to accurately determine the position of the flame from the sensor and the fuel/air ratio. The fuel and/or air flow rate (s) is/are then adjusted to provide reduced flame instability problems such as flashback, combustion dynamics and lean blowout, as well as reduced emissions. The time-varying voltage may be an alternating voltage and the time-varying current may be an alternating current.

Novel shock absorber features varying yield strengths

NASA Technical Reports Server (NTRS)

Geier, D. J.

1964-01-01

A shock absorbent webbing of partially drawn synthetic strands is arranged in sections of varying density related to the varying mass of the human body. This is contoured to protect the body at points of contact, when subjected to large acceleration or deceleration forces.

Maximal isometric muscle strength values obtained By hand-held dynamometry in children between 6 and 15 years of age.

PubMed

Escobar, Raul G; Munoz, Karin T; Dominguez, Angelica; Banados, Pamela; Bravo, Maria J

2017-01-01

In this study we aimed to determine the maximal isometric muscle strength of a healthy, normal-weight, pediatric population between 6 and 15 years of age using hand-held dynamometry to establish strength reference values. The secondary objective was determining the relationship between strength and anthropometric parameters. Four hundred normal-weight Chilean children, split into 10 age groups, separated by 1-year intervals, were evaluated. Each age group included between 35 and 55 children. The strength values increased with increasing age and weight, with a correlation of 0.83 for age and 0.82 for weight. The results were similar to those reported in previous studies regarding the relationships among strength, age, and anthropometric parameters, but the reported strength differed. These results provide normal strength parameters for healthy and normal-weight Chilean children between 6 and 15 years of age and highlight the relevance of ethnicity in defining reference values for muscle strength in a pediatric population. Muscle Nerve 55: 16-22, 2017. © 2016 Wiley Periodicals, Inc.

Analysis of personal and cultural values as key determinants of novel food acceptance. Application to an ethnic product.

PubMed

Barrena, Ramo; García, Teresa; Sánchez, Mercedes

2015-04-01

This paper sets out to analyse whether the complexity and the type of benefits and values pursued in the consumer choice process for a novel food product (couscous) varies with the consumer's ethnic origin (Spanish and Arab). A qualitative study was used to explore these issues in an application of the "means-end chain" theory. The hierarchical value maps obtained point to the presence of an important emotional dimension in the consumption of the selected product, particularly Arab consumers, suggesting that greater familiarity with the product results in a more complex choice process. Some cross-cultural variation can also be observed. Arab consumers attach more importance to issues such as the geographic origin of the product, cultural identification, and fulfilment of family duty. Spanish couscous consumers, meanwhile, claim that it is a way to follow the latest trends, and be more cosmopolitan and more successful within their environment. Copyright © 2014 Elsevier Ltd. All rights reserved.

A MODEL FOR THE SOURCES OF THE SLOWLY VARYING COMPONENT OF MICROWAVE SOLAR RADIATION

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

Swarup, G.; Kakinuma, T.

1962-11-01

A comparison of the observations of the slowly varying component of the solar radio emission made with highresolution interferometers operating at wavelengths of 3.2, strong sources are higher at the longer wavelengths than at 3 cm. The same conclusion is derived from eclipse and statistical investigations, which indicate further that the spectrum of the flux density has a peak around 6 cm. The decrease in flux density with frequency cannot be explained simply by assuming a greater optical thickness for the extraordinary wave near 10 cm in the million-degree corona, as given by the magneto-ionic theory, since the observed degreemore » of polarization at 7.5 or 9.1 cm is much lower than that at 3.2 cm. It is suggested that radiation at the gyrofrequency and its harmonics emitted by the thermal electrons in the dense region over a sunspot group should be raken into account to explain the spectrum of the slowly varying component. This mechanism of resonance absorption requires the average strength of the magnetic field over the sunspot group to be about 800 gauss at a height of 2 x 10/sup 4/ km above the photosphere and 250 gauss at a height of 4 x 10/sup 4/ km. In order to explain the observed values of brightness temperature of 1/-4 x 10/sup 6/ deg K near 10 cm by the magneto-ionic theory, it is necessary to assume values of electron density of up to 20 or 40 times the normal. However, these high values of densities are not required by the gyro-theory, and values of five to ten times the normal are sufficient for explaining simultaneously the observations of brightness temperature, flux density, and polarization. This theory also explains the small size of the source in the range 3-10 cm. The radio emission is considered to originate thermally, which requires that the value of the electron temperature in the region of the inner solar corona above a large sunspot group is about 2-4 x 10 deg K. (auth)« less

Enhancing Established Counting Routines to Promote Place-Value Understanding: An Empirical Study in Early Elementary Classrooms

ERIC Educational Resources Information Center

Fraivillig, Judith L.

2018-01-01

Understanding place value is a critical and foundational competency for elementary mathematics. Classroom teachers who endeavor to promote place-value development adopt a variety of established practices to varying degrees of effectiveness. In parallel, researchers have validated models of how young children acquire place-value understanding.…

Measuring the Accuracy of Simple Evolving Connectionist System with Varying Distance Formulas

NASA Astrophysics Data System (ADS)

Al-Khowarizmi; Sitompul, O. S.; Suherman; Nababan, E. B.

2017-12-01

Simple Evolving Connectionist System (SECoS) is a minimal implementation of Evolving Connectionist Systems (ECoS) in artificial neural networks. The three-layer network architecture of the SECoS could be built based on the given input. In this study, the activation value for the SECoS learning process, which is commonly calculated using normalized Hamming distance, is also calculated using normalized Manhattan distance and normalized Euclidean distance in order to compare the smallest error value and best learning rate obtained. The accuracy of measurement resulted by the three distance formulas are calculated using mean absolute percentage error. In the training phase with several parameters, such as sensitivity threshold, error threshold, first learning rate, and second learning rate, it was found that normalized Euclidean distance is more accurate than both normalized Hamming distance and normalized Manhattan distance. In the case of beta fibrinogen gene -455 G/A polymorphism patients used as training data, the highest mean absolute percentage error value is obtained with normalized Manhattan distance compared to normalized Euclidean distance and normalized Hamming distance. However, the differences are very small that it can be concluded that the three distance formulas used in SECoS do not have a significant effect on the accuracy of the training results.

Deblurring for spatial and temporal varying motion with optical computing

NASA Astrophysics Data System (ADS)

Xiao, Xiao; Xue, Dongfeng; Hui, Zhao

2016-05-01

A way to estimate and remove spatially and temporally varying motion blur is proposed, which is based on an optical computing system. The translation and rotation motion can be independently estimated from the joint transform correlator (JTC) system without iterative optimization. The inspiration comes from the fact that the JTC system is immune to rotation motion in a Cartesian coordinate system. The work scheme of the JTC system is designed to keep switching between the Cartesian coordinate system and polar coordinate system in different time intervals with the ping-pang handover. In the ping interval, the JTC system works in the Cartesian coordinate system to obtain a translation motion vector with optical computing speed. In the pang interval, the JTC system works in the polar coordinate system. The rotation motion is transformed to the translation motion through coordinate transformation. Then the rotation motion vector can also be obtained from JTC instantaneously. To deal with continuous spatially variant motion blur, submotion vectors based on the projective motion path blur model are proposed. The submotion vectors model is more effective and accurate at modeling spatially variant motion blur than conventional methods. The simulation and real experiment results demonstrate its overall effectiveness.

Radiative corrections in the (varying power)-law modified gravity

NASA Astrophysics Data System (ADS)

Hammad, Fayçal

2015-06-01

Although the (varying power)-law modified gravity toy model has the attractive feature of unifying the early- and late-time expansions of the Universe, thanks to the peculiar dependence of the scalar field's potential on the scalar curvature, the model still suffers from the fine-tuning problem when used to explain the actually observed Hubble parameter. Indeed, a more correct estimate of the mass of the scalar field needed to comply with actual observations gives an unnaturally small value. On the other hand, for a massless scalar field the potential would have no minimum and hence the field would always remain massless. What solves these issues are the radiative corrections that modify the field's effective potential. These corrections raise the field's effective mass, rendering the model free from fine-tuning, immune against positive fifth-force tests, and better suited to tackle the dark matter sector.

ANTIRADICAL AND ANTIMICROBIAL ACTIVITY OF PHENOLIC FRACTIONS OBTAINED FROM HONEYS.

PubMed

Mazol, Irena; Sroka, Zbigniew; Sowa, Alina; Ostrowska, Anna; Dryś, Andrzej; Gamian, Andrzej

2016-01-01

Honey is a natural product consisting of multiple components which determine its dietary and medicinal properties. In this work there were studied methanol fractions obtained from seven honeys from Lower Silesia (Poland) collected in different seasons of three successive years. Melissopalynologic studies revealed that two of them were polyfloral, and five were classified as monofloral (two buckwheat and three rapes). The amount of phenolic compounds in honeys varied from 0.09 to 0.38 mg per g of honey. Honeys harvested in 2010 were the richest in phenolic compounds and especially rich was buckwheat honey, comparing to 2011- 2012. Determination of antioxidant potential with the DPPH radical revealed that the strongest antiradical activity was exhibited by extracts obtained from polyfloral (1.22 TAU(515/mg)) and buckwheat (1.06 TAU(515lmg)) honeys, while the highest number of antiradical units was observed for rape honey (3.64 TAU(515/g)). Polyphenolic fractions exhibited various bactericidal activities against Klebsiella pneumoniae and Staphylococcus aureus and weak or no activity was observed against Pseudomonas aeruginosa.

Neural representation of expected value in the adolescent brain.

PubMed

Barkley-Levenson, Emily; Galván, Adriana

2014-01-28

Previous work shows that the adolescent reward system is hyperactive, but this finding may be confounded by differences in how teens value money. To address this, we examined the neural ontogeny of objective value representation. Adolescent and adult participants performed a monetary gambling task in which they chose to accept or reject gambles of varying expected value. Increasing expected value had a stronger influence over gambling choices in adolescents relative to adults, an effect that was paralleled by greater activation in the ventral striatum in adolescents. This unique adolescent ventral striatum response remained even after matching groups on acceptance behavior. These behavioral and neural data suggest that the value of available options has a greater influence in adolescent versus adult choices, even when objective value and subjective choice are held constant. This research provides further evidence that hyperactivation of reward circuitry in adolescence may be a normative ontogenetic shift that is due to greater valuation in the adolescent brain.

Neural representation of expected value in the adolescent brain

PubMed Central

Barkley-Levenson, Emily; Galván, Adriana

2014-01-01

Previous work shows that the adolescent reward system is hyperactive, but this finding may be confounded by differences in how teens value money. To address this, we examined the neural ontogeny of objective value representation. Adolescent and adult participants performed a monetary gambling task in which they chose to accept or reject gambles of varying expected value. Increasing expected value had a stronger influence over gambling choices in adolescents relative to adults, an effect that was paralleled by greater activation in the ventral striatum in adolescents. This unique adolescent ventral striatum response remained even after matching groups on acceptance behavior. These behavioral and neural data suggest that the value of available options has a greater influence in adolescent versus adult choices, even when objective value and subjective choice are held constant. This research provides further evidence that hyperactivation of reward circuitry in adolescence may be a normative ontogenetic shift that is due to greater valuation in the adolescent brain. PMID:24474790

Calculating a Continuous Metabolic Syndrome Score Using Nationally Representative Reference Values.

PubMed

Guseman, Emily Hill; Eisenmann, Joey C; Laurson, Kelly R; Cook, Stephen R; Stratbucker, William

2018-02-26

The prevalence of metabolic syndrome in youth varies on the basis of the classification system used, prompting implementation of continuous scores; however, the use of these scores is limited to the sample from which they were derived. We sought to describe the derivation of the continuous metabolic syndrome score using nationally representative reference values in a sample of obese adolescents and a national sample obtained from National Health and Nutrition Examination Survey (NHANES) 2011-2012. Clinical data were collected from 50 adolescents seeking obesity treatment at a stage 3 weight management center. A second analysis relied on data from adolescents included in NHANES 2011-2012, performed for illustrative purposes. The continuous metabolic syndrome score was calculated by regressing individual values onto nationally representative age- and sex-specific standards (NHANES III). Resultant z scores were summed to create a total score. The final sample included 42 obese adolescents (15 male and 35 female subjects; mean age, 14.8 ± 1.9 years) and an additional 445 participants from NHANES 2011-2012. Among the clinical sample, the mean continuous metabolic syndrome score was 4.16 ± 4.30, while the NHANES sample mean was quite a bit lower, at -0.24 ± 2.8. We provide a method to calculate the continuous metabolic syndrome by comparing individual risk factor values to age- and sex-specific percentiles from a nationally representative sample. Copyright © 2018 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

Stability analysis for uncertain switched neural networks with time-varying delay.

PubMed

Shen, Wenwen; Zeng, Zhigang; Wang, Leimin

2016-11-01

In this paper, stability for a class of uncertain switched neural networks with time-varying delay is investigated. By exploring the mode-dependent properties of each subsystem, all the subsystems are categorized into stable and unstable ones. Based on Lyapunov-like function method and average dwell time technique, some delay-dependent sufficient conditions are derived to guarantee the exponential stability of considered uncertain switched neural networks. Compared with general results, our proposed approach distinguishes the stable and unstable subsystems rather than viewing all subsystems as being stable, thus getting less conservative criteria. Finally, two numerical examples are provided to show the validity and the advantages of the obtained results. Copyright © 2016 Elsevier Ltd. All rights reserved.

Surrogate markers for time-varying treatments and outcomes

PubMed Central

Hsu, Jesse Y; Kennedy, Edward H; Roy, Jason A; Stephens-Shields, Alisa J; Small, Dylan S; Joffe, Marshall M

2015-01-01

Background A surrogate marker is a variable commonly used in clinical trials to guide treatment decisions when the outcome of ultimate interest is not available. A good surrogate marker is one where the treatment effect on the surrogate is a strong predictor of the effect of treatment on the outcome. We review the situation when there is one treatment delivered at baseline, one surrogate measured at one later time point and one ultimate outcome of interest, and discuss new issues arising when variables are time-varying. Methods Most of the literature on surrogate markers has only considered simple settings with one treatment, one surrogate, and one outcome of interest at a fixed time point. However, more complicated time-varying settings are common in practice. In this paper, we describe the unique challenges in two settings, time-varying treatments and time-varying surrogates, while relating the ideas back to the causal-effects and causal-association paradigms. Conclusions In addition to discussing and extending popular notions of surrogacy to time-varying settings, we give examples illustrating that one can be misled by not taking into account time-varying information about the surrogate or treatment. We hope this paper has provided some motivation for future work on estimation and inference in such settings. PMID:25948621

A precise and accurate acupoint location obtained on the face using consistency matrix pointwise fusion method.

PubMed

Yanq, Xuming; Ye, Yijun; Xia, Yong; Wei, Xuanzhong; Wang, Zheyu; Ni, Hongmei; Zhu, Ying; Xu, Lingyu

2015-02-01

To develop a more precise and accurate method, and identified a procedure to measure whether an acupoint had been correctly located. On the face, we used an acupoint location from different acupuncture experts and obtained the most precise and accurate values of acupoint location based on the consistency information fusion algorithm, through a virtual simulation of the facial orientation coordinate system. Because of inconsistencies in each acupuncture expert's original data, the system error the general weight calculation. First, we corrected each expert of acupoint location system error itself, to obtain a rational quantification for each expert of acupuncture and moxibustion acupoint location consistent support degree, to obtain pointwise variable precision fusion results, to put every expert's acupuncture acupoint location fusion error enhanced to pointwise variable precision. Then, we more effectively used the measured characteristics of different acupuncture expert's acupoint location, to improve the measurement information utilization efficiency and acupuncture acupoint location precision and accuracy. Based on using the consistency matrix pointwise fusion method on the acupuncture experts' acupoint location values, each expert's acupoint location information could be calculated, and the most precise and accurate values of each expert's acupoint location could be obtained.

A model for filtered backprojection reconstruction artifacts due to time-varying attenuation values in perfusion C-arm CT.

PubMed

Fieselmann, Andreas; Dennerlein, Frank; Deuerling-Zheng, Yu; Boese, Jan; Fahrig, Rebecca; Hornegger, Joachim

2011-06-21

Filtered backprojection is the basis for many CT reconstruction tasks. It assumes constant attenuation values of the object during the acquisition of the projection data. Reconstruction artifacts can arise if this assumption is violated. For example, contrast flow in perfusion imaging with C-arm CT systems, which have acquisition times of several seconds per C-arm rotation, can cause this violation. In this paper, we derived and validated a novel spatio-temporal model to describe these kinds of artifacts. The model separates the temporal dynamics due to contrast flow from the scan and reconstruction parameters. We introduced derivative-weighted point spread functions to describe the spatial spread of the artifacts. The model allows prediction of reconstruction artifacts for given temporal dynamics of the attenuation values. Furthermore, it can be used to systematically investigate the influence of different reconstruction parameters on the artifacts. We have shown that with optimized redundancy weighting function parameters the spatial spread of the artifacts around a typical arterial vessel can be reduced by about 70%. Finally, an inversion of our model could be used as the basis for novel dynamic reconstruction algorithms that further minimize these artifacts.

Tracking the time-varying cortical connectivity patterns by adaptive multivariate estimators.

PubMed

Astolfi, L; Cincotti, F; Mattia, D; De Vico Fallani, F; Tocci, A; Colosimo, A; Salinari, S; Marciani, M G; Hesse, W; Witte, H; Ursino, M; Zavaglia, M; Babiloni, F

2008-03-01

The directed transfer function (DTF) and the partial directed coherence (PDC) are frequency-domain estimators that are able to describe interactions between cortical areas in terms of the concept of Granger causality. However, the classical estimation of these methods is based on the multivariate autoregressive modelling (MVAR) of time series, which requires the stationarity of the signals. In this way, transient pathways of information transfer remains hidden. The objective of this study is to test a time-varying multivariate method for the estimation of rapidly changing connectivity relationships between cortical areas of the human brain, based on DTF/PDC and on the use of adaptive MVAR modelling (AMVAR) and to apply it to a set of real high resolution EEG data. This approach will allow the observation of rapidly changing influences between the cortical areas during the execution of a task. The simulation results indicated that time-varying DTF and PDC are able to estimate correctly the imposed connectivity patterns under reasonable operative conditions of signal-to-noise ratio (SNR) ad number of trials. An SNR of five and a number of trials of at least 20 provide a good accuracy in the estimation. After testing the method by the simulation study, we provide an application to the cortical estimations obtained from high resolution EEG data recorded from a group of healthy subject during a combined foot-lips movement and present the time-varying connectivity patterns resulting from the application of both DTF and PDC. Two different cortical networks were detected with the proposed methods, one constant across the task and the other evolving during the preparation of the joint movement.

The social construction of copyright ethics and values.

PubMed

Slaughter, Sheila; Rhoades, Gary

2010-06-01

This study is based on analysis of copyright policies and 26 interviews with science and engineering faculty at three research universities on the topic of copyright beliefs, values, and practices, with emphasis on copyright of instructional materials, courseware, tools, and texts. Given that research universities now emphasize increasing external revenue flows through marketing of intellectual property, we expected copyright to follow the path of patents and lead to institutional emphasis of policies and practices that enhanced universities' intellectual property portfolios, accompanied by an increase in copyrighting by professors. Although this pattern occurred with regard to institutions, professors offered a more varied pattern, with some fully participating in commercialization of copyright and embracing entrepreneurial values, while others resisted or subverted commercial activity in favor of traditional science and engineering values.

Comparison of histomorphometrical data obtained with two different image analysis methods.

PubMed

Ballerini, Lucia; Franke-Stenport, Victoria; Borgefors, Gunilla; Johansson, Carina B

2007-08-01

A common way to determine tissue acceptance of biomaterials is to perform histomorphometrical analysis on histologically stained sections from retrieved samples with surrounding tissue, using various methods. The "time and money consuming" methods and techniques used are often "in house standards". We address light microscopic investigations of bone tissue reactions on un-decalcified cut and ground sections of threaded implants. In order to screen sections and generate results faster, the aim of this pilot project was to compare results generated with the in-house standard visual image analysis tool (i.e., quantifications and judgements done by the naked eye) with a custom made automatic image analysis program. The histomorphometrical bone area measurements revealed no significant differences between the methods but the results of the bony contacts varied significantly. The raw results were in relative agreement, i.e., the values from the two methods were proportional to each other: low bony contact values in the visual method corresponded to low values with the automatic method. With similar resolution images and further improvements of the automatic method this difference should become insignificant. A great advantage using the new automatic image analysis method is that it is time saving--analysis time can be significantly reduced.

Learning Time-Varying Coverage Functions

PubMed Central

Du, Nan; Liang, Yingyu; Balcan, Maria-Florina; Song, Le

2015-01-01

Coverage functions are an important class of discrete functions that capture the law of diminishing returns arising naturally from applications in social network analysis, machine learning, and algorithmic game theory. In this paper, we propose a new problem of learning time-varying coverage functions, and develop a novel parametrization of these functions using random features. Based on the connection between time-varying coverage functions and counting processes, we also propose an efficient parameter learning algorithm based on likelihood maximization, and provide a sample complexity analysis. We applied our algorithm to the influence function estimation problem in information diffusion in social networks, and show that with few assumptions about the diffusion processes, our algorithm is able to estimate influence significantly more accurately than existing approaches on both synthetic and real world data. PMID:25960624

Learning Time-Varying Coverage Functions.

PubMed

Du, Nan; Liang, Yingyu; Balcan, Maria-Florina; Song, Le

2014-12-08

Coverage functions are an important class of discrete functions that capture the law of diminishing returns arising naturally from applications in social network analysis, machine learning, and algorithmic game theory. In this paper, we propose a new problem of learning time-varying coverage functions, and develop a novel parametrization of these functions using random features. Based on the connection between time-varying coverage functions and counting processes, we also propose an efficient parameter learning algorithm based on likelihood maximization, and provide a sample complexity analysis. We applied our algorithm to the influence function estimation problem in information diffusion in social networks, and show that with few assumptions about the diffusion processes, our algorithm is able to estimate influence significantly more accurately than existing approaches on both synthetic and real world data.

Time-varying trends of global vegetation activity

NASA Astrophysics Data System (ADS)

Pan, N.; Feng, X.; Fu, B.

2016-12-01

Vegetation plays an important role in regulating the energy change, water cycle and biochemical cycle in terrestrial ecosystems. Monitoring the dynamics of vegetation activity and understanding their driving factors have been an important issue in global change research. Normalized Difference Vegetation Index (NDVI), an indicator of vegetation activity, has been widely used in investigating vegetation changes at regional and global scales. Most studies utilized linear regression or piecewise linear regression approaches to obtain an averaged changing rate over a certain time span, with an implicit assumption that the trend didn't change over time during that period. However, no evidence shows that this assumption is right for the non-linear and non-stationary NDVI time series. In this study, we adopted the multidimensional ensemble empirical mode decomposition (MEEMD) method to extract the time-varying trends of NDVI from original signals without any a priori assumption of their functional form. Our results show that vegetation trends are spatially and temporally non-uniform during 1982-2013. Most vegetated area exhibited greening trends in the 1980s. Nevertheless, the area with greening trends decreased over time since the early 1990s, and the greening trends have stalled or even reversed in many places. Regions with browning trends were mainly located in southern low latitudes in the 1980s, whose area decreased before the middle 1990s and then increased at an accelerated rate. The greening-to-browning reversals were widespread across all continents except Oceania (43% of the vegetated areas), most of which happened after the middle 1990s. In contrast, the browning-to-greening reversals occurred in smaller area and earlier time. The area with monotonic greening and browning trends accounted for 33% and 5% of the vegetated area, respectively. By performing partial correlation analyses between NDVI and climatic elements (temperature, precipitation and cloud cover

Full characterization of modular values for finite-dimensional systems

NASA Astrophysics Data System (ADS)

Ho, Le Bin; Imoto, Nobuyuki

2016-06-01

Kedem and Vaidman obtained a relationship between the spin-operator modular value and its weak value for specific coupling strengths [14]. Here we give a general expression for the modular value in the n-dimensional Hilbert space using the weak values up to (n - 1)th order of an arbitrary observable for any coupling strength, assuming non-degenerated eigenvalues. For two-dimensional case, it shows a linear relationship between the weak value and the modular value. We also relate the modular value of the sum of observables to the weak value of their product.

Generalized semiparametric varying-coefficient models for longitudinal data

NASA Astrophysics Data System (ADS)

Qi, Li

In this dissertation, we investigate the generalized semiparametric varying-coefficient models for longitudinal data that can flexibly model three types of covariate effects: time-constant effects, time-varying effects, and covariate-varying effects, i.e., the covariate effects that depend on other possibly time-dependent exposure variables. First, we consider the model that assumes the time-varying effects are unspecified functions of time while the covariate-varying effects are parametric functions of an exposure variable specified up to a finite number of unknown parameters. The estimation procedures are developed using multivariate local linear smoothing and generalized weighted least squares estimation techniques. The asymptotic properties of the proposed estimators are established. The simulation studies show that the proposed methods have satisfactory finite sample performance. ACTG 244 clinical trial of HIV infected patients are applied to examine the effects of antiretroviral treatment switching before and after HIV developing the 215-mutation. Our analysis shows benefit of treatment switching before developing the 215-mutation. The proposed methods are also applied to the STEP study with MITT cases showing that they have broad applications in medical research.

Vector curvaton with varying kinetic function

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

Dimopoulos, Konstantinos; Karciauskas, Mindaugas; Wagstaff, Jacques M.

2010-01-15

A new model realization of the vector curvaton paradigm is presented and analyzed. The model consists of a single massive Abelian vector field, with a Maxwell-type kinetic term. By assuming that the kinetic function and the mass of the vector field are appropriately varying during inflation, it is shown that a scale-invariant spectrum of superhorizon perturbations can be generated. These perturbations can contribute to the curvature perturbation of the Universe. If the vector field remains light at the end of inflation it is found that it can generate substantial statistical anisotropy in the spectrum and bispectrum of the curvature perturbation.more » In this case the non-Gaussianity in the curvature perturbation is predominantly anisotropic, which will be a testable prediction in the near future. If, on the other hand, the vector field is heavy at the end of inflation then it is demonstrated that particle production is approximately isotropic and the vector field alone can give rise to the curvature perturbation, without directly involving any fundamental scalar field. The parameter space for both possibilities is shown to be substantial. Finally, toy models are presented which show that the desired variation of the mass and kinetic function of the vector field can be realistically obtained, without unnatural tunings, in the context of supergravity or superstrings.« less

[Reference values of energy for the Venezuelan population].

PubMed

Landaeta-Jiménez, Maritza; Aliaga, Carla; Sifontes, Yaritza; Vásquez, Maura; Ramírez, Guillermo; Falque Madrid, Luís; Herrera, Marianella; María Reyes, Ana; Emilia, Elzakem; Herrera, Ctor; Bernal, Jennifer

2013-12-01

The project of updating the Venezuelan energy reference values respond to the recommendations made by an FAO experts committee, several decades ago for the countries assuming this work. Because of the dramatic changes experienced globally regarding energy intake/expenditure and particularly variations on the Venezuelan nutritional scenario with the presence of "the double burden of malnutrition" it a review of Energy Reference Values (VRE) from a more integral approach is pertinent. This report follows the methodology proposed by FAO/WHO/UNU 2004 experts committee and energy reference values were established by group of age and gender, also average energy values for Venezuelan population were obtained. For calculation of these requirements, the energy expenditure was included by taking into account Basal Metabolic Rate and physical activity level for some specific groups. The score average values updated in 2012 of 2.200 kcal/dia reported to be lower than those of 2000 at all ages for masculine gender except for the 16-17 age group and for feminine gender just until ages 10-12 years and from there are slightly above the values obtained in 2000.

Derivation of the extrinsic values of biological diversity from its intrinsic value and of both from the first principles of evolution.

PubMed

White, Peter S

2013-12-01

Conservation ethics have been based on 2 philosophical value systems: extrinsic value (defined broadly to include all values that derive from something external to the thing valued) and intrinsic value. Valuing biological diversity on the basis of an extrinsic value system is problematic because measurement is often difficult; extrinsic value changes as spatial or temporal scales change; extrinsic value differs on the basis of external factors; some species have trivial or negative extrinsic values; and extrinsic value varies across human cultures and societies and with such factors as socioeconomic conditions, individual experiences, and educational backgrounds. Valuing biological diversity on the basis of an intrinsic value system also poses challenges because intrinsic value can be seen as a disguised form of human extrinsic value; intrinsic value is initially ambiguous as to which objects or characteristics of biological diversity are to being valued; all aspects of biological diversity (e.g., species and ecosystems) are transitory; species and ecosystems are not static concrete entities; and intrinsic value of one species is often in conflict with the intrinsic value of other species. Extrinsic and intrinsic value systems share a common origin, such that extrinsic values are always derived from intrinsic value and life mutely expresses both intrinsic and extrinsic values-these are derived from and are products of biological evolution. Probing the values that underlie conservation helps the community clearly articulate its aims. Derivación de los Valores Extrínsecos de la Biodiversidad a Partir de sus Valores Intrínsecos y de Ambos a Partir de los Primeros Principios de la Evolución. © 2013 Society for Conservation Biology.

Failure to obtain value enhancement by within-trial contrast in simultaneous and successive discriminations.

PubMed

Arantes, Joana; Grace, Randolph C

2008-02-01

The present research tested the generality of the "work ethic" effect described by Clement, Feltus, Kaiser, and Zentall (2000). In Experiment 1, we trained 10 pigeons on a pair of either simultaneous or successive discriminations. One discrimination followed a high-effort requirement (20 pecks to the center key) and the other followed a low-effort requirement (1 peck). Contrary to Clement et al.'s results, we found that preferences between the S+ and S- stimuli in transfer tests depended on the event that initiated the trial: Pigeons preferred the stimulus from the baseline discrimination whose initiating event was most dissimilar from that preceding the test trial. Preferences were similar but less extreme in the successive condition. In Experiment 2, we investigated whether test preferences depended on the amount of training. A total of 12 pigeons were trained on a pair of simultaneous discriminations, except that test sessions were scheduled after every three baseline sessions. Preferences increased across test sessions but were similar to those in Experiment 1. Together with Vasconcelos, Urcuioli, and Lionello-DeNolf (2007a), our study represents a second failure to replicate Clement et al.'s work ethic effect. The finding that preference depends on the event that initiates the test trial suggests that choice probes may not provide unambiguous assessments of stimulus value.

Hematocrit and plasma osmolality values of young-of-year shortnose sturgeon following acute exposures to combinations of salinity and temperature

USGS Publications Warehouse

Ziegeweid, J.R.; Black, M.C.

2010-01-01

Little is known about the physiological capabilities of young-of-year (YOY) shortnose sturgeon. In this study, plasma osmolality and hematocrit values were measured for YOY shortnose sturgeon following 48-h exposures to 12 different combinations of salinity and temperature. Hematocrit levels varied significantly with temperature and age, and plasma osmolalities varied significantly with salinity and age. Plasma osmolality and hematocrit values were similar to previously published values for other sturgeons of similar age and size in similar treatment conditions. ?? 2010 Springer Science+Business Media B.V.

Synchronized state of coupled dynamics on time-varying networks.

PubMed

Amritkar, R E; Hu, Chin-Kun

2006-03-01

We consider synchronization properties of coupled dynamics on time-varying networks and the corresponding time-average network. We find that if the different Laplacians corresponding to the time-varying networks commute with each other then the stability of the synchronized state for both the time-varying and the time-average topologies are approximately the same. On the other hand for noncommuting Laplacians the stability of the synchronized state for the time-varying topology is in general better than the time-average topology.

Using Publicly Available Data to Construct a Transparent Measure of Health Care Value: A Method and Initial Results.

PubMed

Weeks, William B; Kotzbauer, Gregory R; Weinstein, James N

2016-06-01

Using publicly available Hospital Compare and Medicare data, we found a substantial range of hospital-level performance on quality, expenditure, and value measures for 4 common reasons for admission. Hospitals' ability to consistently deliver high-quality, low-cost care varied across the different reasons for admission. With the exception of coronary artery bypass grafting, hospitals that provided the highest-value care had more beds and a larger average daily census than those providing the lowest-value care. Transparent data like those we present can empower patients to compare hospital performance, make better-informed treatment decisions, and decide where to obtain care for particular health care problems. In the United States, the transition from volume to value dominates discussions of health care reform. While shared decision making might help patients determine whether to get care, transparency in procedure- and hospital-specific value measures would help them determine where to get care. Using Hospital Compare and Medicare expenditure data, we constructed a hospital-level measure of value from a numerator composed of quality-of-care measures (satisfaction, use of timely and effective care, and avoidance of harms) and a denominator composed of risk-adjusted 30-day episode-of-care expenditures for acute myocardial infarction (1,900 hospitals), coronary artery bypass grafting (884 hospitals), colectomy (1,252 hospitals), and hip replacement surgery (1,243 hospitals). We found substantial variation in aggregate measures of quality, cost, and value at the hospital level. Value calculation provided additional richness when compared to assessment based on quality or cost alone: about 50% of hospitals in an extreme quality- (and about 65% more in an extreme cost-) quintile were in the same extreme value quintile. With the exception of coronary artery bypass grafting, higher-value hospitals were larger and had a higher average daily census than lower-value

Computation of rapidly varied unsteady, free-surface flow

USGS Publications Warehouse

Basco, D.R.

1987-01-01

Many unsteady flows in hydraulics occur with relatively large gradients in free surface profiles. The assumption of hydrostatic pressure distribution with depth is no longer valid. These are rapidly-varied unsteady flows (RVF) of classical hydraulics and also encompass short wave propagation of coastal hydraulics. The purpose of this report is to present an introductory review of the Boussinnesq-type differential equations that describe these flows and to discuss methods for their numerical integration. On variable slopes and for large scale (finite-amplitude) disturbances, three independent derivational methods all gave differences in the motion equation for higher order terms. The importance of these higher-order terms for riverine applications must be determined by numerical experiments. Care must be taken in selection of the appropriate finite-difference scheme to minimize truncation error effects and the possibility of diverging (double mode) numerical solutions. It is recommended that practical hydraulics cases be established and tested numerically to demonstrate the order of differences in solution with those obtained from the long wave equations of St. Venant. (USGS)

Realization of arbitrarily long focus-depth optical vortices with spiral area-varying zone plates

NASA Astrophysics Data System (ADS)

Zheng, Chenglong; Zang, Huaping; Du, Yanli; Tian, Yongzhi; Ji, Ziwen; Zhang, Jing; Fan, Quanping; Wang, Chuanke; Cao, Leifeng; Liang, Erjun

2018-05-01

We provide a methodology to realize an optical vortex with arbitrarily long focus-depth. With a technique of varying each zone area of a phase spiral zone plate one can obtain optics capable of generating ultra-long focus-depth optical vortex from a plane wave. The focal property of such optics was analysed using the Fresnel diffraction theory, and an experimental demonstration was performed to verify its effectiveness. Such optics may bring new opportunity and benefits for optical vortex application such as optical manipulation and lithography.

A Validity and Reliability Study on the Development of the Values Scale in Turkey

ERIC Educational Resources Information Center

Dilmac, Bulent; Aricak, Osman Tolga; Cesur, Sevim

2014-01-01

The purpose of the present study is to examine the initial psychometric properties of the Values Scale for adults. While developing the first stage of the Values Scale, open-ended data on the values held by 216 university students were obtained. During the second stage, the validity and reliability studies of the 60-item Values Scale obtained by…

Balancing tradeoffs: Reconciling multiple environmental goals when ecosystem services vary regionally

NASA Astrophysics Data System (ADS)

O’Connell, Christine S.; Carlson, Kimberly M.; Cuadra, Santiago; Feeley, Kenneth J.; Gerber, James; West, Paul C.; Polasky, Stephen

2018-06-01

As the planet’s dominant land use, agriculture often competes with the preservation of natural systems that provide globally and regionally important ecosystem services. How agriculture impacts ecosystem service delivery varies regionally, among services being considered, and across spatial scales. Here, we assess the tradeoffs between four ecosystem services—agricultural production, carbon storage, biophysical climate regulation, and biodiversity—using as a case study the Amazon, an active frontier of agricultural expansion. We find that the highest values for each of the ecosystem services are concentrated in different regions. Agricultural production potential and carbon storage are highest in the north and west, biodiversity greatest in the west, and climate regulation services most vulnerable to disruption in the south and east. Using a simple optimization model, we find that under scenarios of agricultural expansion that optimize total production across ecosystem services, small increases in priority for one ecosystem service can lead to reductions in other services by as much as 140%. Our results highlight the difficulty of managing landscapes for multiple environmental goals; the approach presented here can be adapted to guide value-laden conservation decisions and identify potential solutions that balance priorities.

Marijuana smoking: effects of varying puff volume and breathhold duration.

PubMed

Azorlosa, J L; Greenwald, M K; Stitzer, M L

1995-02-01

Two studies were conducted to quantify biological and behavioral effects resulting from exposure to controlled doses of marijuana smoke. In one study, puff volume (30, 60 and 90 ml) and in a second study, breathhold duration (0, 10 and 20 sec) were systematically varied while holding constant other smoking topography parameters (number of puffs = 10, interpuff interval = 60 sec and inhalation volume = 25% of vital capacity). Each study also varied levels of delta 9-tetrahydro-cannabinol marijuana cigarette content (1.75% and 3.55%). Regular marijuana users served as subjects (n = 7 in each experiment). Subjects smoked 10 puffs in each of six sessions; a seventh, nonsmoking session (all measures recorded at the same times as in active smoking sessions) served as a control. Variations in puff volume produced significant dose-related changes in postsmoking plasma delta 9-tetrahydro-cannabinol levels, carbon monoxide boost and subjective effects (e.g., "high"). In contrast, breathholding for 10 or 20 sec versus 0 sec increased plasma delta 9-tetrahydro-cannabinol levels but not CO boost or subjective effects. Task performance measures were not reliably influenced by marijuana smoke exposure within the dosing ranges examined. These findings confirm the utility of the controlled smoking technology, support the notion that cumulative puff volume systematically influences biological exposure and subjective effects, but cast doubt on the common belief that prolonged breathholding of marijuana smoke enhances classical subjective effects associated with its reinforcing value in humans.

Correcting for Measurement Error in Time-Varying Covariates in Marginal Structural Models.

PubMed

Kyle, Ryan P; Moodie, Erica E M; Klein, Marina B; Abrahamowicz, Michał

2016-08-01

Unbiased estimation of causal parameters from marginal structural models (MSMs) requires a fundamental assumption of no unmeasured confounding. Unfortunately, the time-varying covariates used to obtain inverse probability weights are often error-prone. Although substantial measurement error in important confounders is known to undermine control of confounders in conventional unweighted regression models, this issue has received comparatively limited attention in the MSM literature. Here we propose a novel application of the simulation-extrapolation (SIMEX) procedure to address measurement error in time-varying covariates, and we compare 2 approaches. The direct approach to SIMEX-based correction targets outcome model parameters, while the indirect approach corrects the weights estimated using the exposure model. We assess the performance of the proposed methods in simulations under different clinically plausible assumptions. The simulations demonstrate that measurement errors in time-dependent covariates may induce substantial bias in MSM estimators of causal effects of time-varying exposures, and that both proposed SIMEX approaches yield practically unbiased estimates in scenarios featuring low-to-moderate degrees of error. We illustrate the proposed approach in a simple analysis of the relationship between sustained virological response and liver fibrosis progression among persons infected with hepatitis C virus, while accounting for measurement error in γ-glutamyltransferase, using data collected in the Canadian Co-infection Cohort Study from 2003 to 2014. © The Author 2016. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

pKa of fentanyl varies with temperature: implications for acid-base management during extremes of body temperature.

PubMed

Thurlkill, Richard L; Cross, David A; Scholtz, J Martin; Pace, C Nick

2005-12-01

The pKa of fentanyl has not been measured previously at varying extremes of body temperature. The goal of this laboratory investigation was to test the hypothesis that the pKa of fentanyl changes with temperature. The investigation involved measuring the pKa values of aqueous fentanyl at varying temperatures. The investigation was conducted in a controlled laboratory environment. No human or animal subjects were involved. Because no live subjects were involved in the investigation, no interventions were necessary. This paper reports the effect of temperature on the pKa of fentanyl. The pKa of aqueous fentanyl was measured at 15 degrees C, 25 degrees C, 37 degrees C, 42 degrees C, and 47.5 degrees C by potentiometric titration in 0.01 mmol/L of potassium chloride after extensive degassing. Data were analyzed using the least squares method with an appropriately fitting equation. The pKa of fentanyl was found to change in a similar manner to the neutral point of water at varying temperatures. This finding has implications for the bioavailability of fentanyl at extremes of body temperature in association with the clinical acid-base management of the patient. Clinical implications for differing methods of intraoperative acid-base management at varying temperatures are discussed.

Whey-derived valuable products obtained by microbial fermentation.

PubMed

Pescuma, Micaela; de Valdez, Graciela Font; Mozzi, Fernanda

2015-08-01

Whey, the main by-product of the cheese industry, is considered as an important pollutant due to its high chemical and biological oxygen demand. Whey, often considered as waste, has high nutritional value and can be used to obtain value-added products, although some of them need expensive enzymatic synthesis. An economical alternative to transform whey into valuable products is through bacterial or yeast fermentations and by accumulation during algae growth. Fermentative processes can be applied either to produce individual compounds or to formulate new foods and beverages. In the first case, a considerable amount of research has been directed to obtain biofuels able to replace those derived from petrol. In addition, the possibility of replacing petrol-derived plastics by biodegradable polymers synthesized during bacterial fermentation of whey has been sought. Further, the ability of different organisms to produce metabolites commonly used in the food and pharmaceutical industries (i.e., lactic acid, lactobionic acid, polysaccharides, etc.) using whey as growth substrate has been studied. On the other hand, new low-cost functional whey-based foods and beverages leveraging the high nutritional quality of whey have been formulated, highlighting the health-promoting effects of fermented whey-derived products. This review aims to gather the multiple uses of whey as sustainable raw material for the production of individual compounds, foods, and beverages by microbial fermentation. This is the first work to give an overview on the microbial transformation of whey as raw material into a large repertoire of industrially relevant foods and products.

Improving Value in Musculoskeletal Care Delivery: AOA Critical Issues.

PubMed

Wei, David H; Hawker, Gillian A; Jevsevar, David S; Bozic, Kevin J

2015-05-06

Improving value in musculoskeletal health care has emerged as an important objective in both the United States and Canada. In order to achieve this objective, providers need to have a clear definition of value and an infrastructure for measuring outcomes of interest to patients and costs over the episode of care. Although national patient registries have been established in the United States and Canada, they nevertheless lag behind other registries worldwide in terms of collecting patient-reported outcomes and capturing data from a wide cross-section of hospitals and physicians. With the help of professional medical societies and the creation of national initiatives, patient-reported outcomes data collection on a large scale may be possible, but many challenges remain regarding implementation. Alternatives to the fee-for-service payment model, including pay-for-reporting and pay-for-performance, may help incentivize physicians and health-care providers to obtain and improve on patient-reported outcomes data collection. Other payment reforms, such as bundled payments, have been piloted in certain regions, but their sustainability and long-term success are unclear at this time. Novel health-care delivery strategies aimed at improving quality, coordinating multispecialty care, and enhancing patient participation in shared decision-making have shown promise in improving patient-centered outcomes, but delivery models continue to vary greatly throughout the United States and Canada. The current status of musculoskeletal health-care delivery requires substantial change before the goal of improving patient outcomes and lowering health-care costs can be achieved. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

Evaluation of True Power Luminous Efficiency from Experimental Luminance Values

NASA Astrophysics Data System (ADS)

Tsutsui, Tetsuo; Yamamato, Kounosuke

1999-05-01

A method for obtaining true external power luminous efficiencyfrom experimentally obtained luminance in organic light-emittingdiodes (LEDs) wasdemonstrated. Conventional two-layer organic LEDs with different electron-transport layer thicknesses wereprepared. Spatial distributions of emission intensities wereobserved. The large deviation in both emission spectra and spatialemission patterns were observed when the electron-transport layerthickness was varied. The deviation of emission patterns from thestandard Lambertian pattern was found to cause overestimations ofpower luminous efficiencies as large as 30%. A method for evaluatingcorrection factors was proposed.

Fungicidal values of bio-oils and their lignin-rich fractions obtained from wood/bark fast pyrolysis.

PubMed

Mohan, Dinesh; Shi, Jenny; Nicholas, Darrel D; Pittman, Charles U; Steele, Philip H; Cooper, Jerome E

2008-03-01

Pine wood, pine bark, oak wood and oak bark were pyrolyzed in an auger reactor. A total of 16 bio-oils or pyrolytic oils were generated at different temperatures and residence times. Two additional pine bio-oils were produced at the National Renewable Energy Laboratory in a fluidized-bed reactor at different temperatures. All these bio-oils were fractionated to obtain lignin-rich fractions which consist mainly of phenols and neutrals. The pyrolytic lignin-rich fractions were obtained by liquid-liquid extraction. Whole bio-oils and their lignin-rich fractions were studied as potential environmentally benign wood preservatives to replace metal-based CCA and copper systems that have raised environmental concerns. Each bio-oil and several lignin-rich fractions were tested for antifungal properties. Soil block tests were conducted using one brown-rot fungus (Gloeophyllum trabeum) and one white-rot fungus (Trametes versicolor). The lignin-rich fractions showed greater fungal inhibition than whole bio-oils for a impregnation solution 10% concentration level. Water repellence tests were also performed to study wood wafer swelling behavior before and after bio-oil and lignin-rich fraction treatments. In this case, bio-oil fractions did not exhibit higher water repellency than whole bio-oils. Comparison of raw bio-oils in soil block tests, with unleached wafers, at 10% and 25% bio-oil impregnation solution concentration levels showed excellent wood preservation properties at the 25% level. The good performance of raw bio-oils at higher loading levels suggests that fractionation to generate lignin-rich fractions is unnecessary. At this more effective 25% loading level in general, the raw bio-oils performed similarly. Prevention of leaching is critically important for both raw bio-oils and their fractions to provide decay resistance. Initial tests of a polymerization chemical to prevent leaching showed some success.

The deflection of circular mirrors of linearly varying thickness supported along a central hole and free along the outer edge.

PubMed

Prevenslik, T V

1968-10-01

Most cassegrainian mirrors supported along the central hole are designed for deflection tolerances using the theory for solid, constant thickness plates. Where tolerances are critical, the mirror is usually made thicker, thereby reducing the deflection, but also increasing the weight of the mirror. Weight can be reduced by using a honeycomb design; however, manufacturing problems result because of the inherent complexity. To circumvent the disadvantages of excessive weight in the solid, constant thickness design and the complexity of the honeycomb design, a lightweight, yet simple design would be desirable. A possible lightweight, yet simple design would be a solid mirror of linearly varying thickness, decreasing in thickness from the center to the outer edge. As mirrors of linearly varying thickness may provide the best solution under combined deflection and weight restraints, a design basis is required and found in small deflection plate theory. The work of H. Conway was extended to account for pressure loading proportional to mirror density for the case when Poisson's ratio is ?. Closed form solutions for the slope of the linearly varying thickness mirrors were obtained for fixed and simply supported boundary conditions along the central hole. Maximum deflections were obtained by numerical integration and compared with the results for comparable constant thickness mirrors.

Investigation of Sunspot Area Varying with Sunspot Number

NASA Astrophysics Data System (ADS)

Li, K. J.; Li, F. Y.; Zhang, J.; Feng, W.

2016-11-01

The statistical relationship between sunspot area (SA) and sunspot number (SN) is investigated through analysis of their daily observation records from May 1874 to April 2015. For a total of 1607 days, representing 3 % of the total interval considered, either SA or SN had a value of zero while the other parameter did not. These occurrences most likely reflect the report of short-lived spots by a single observatory and subsequent averaging of zero values over multiple stations. The main results obtained are as follows: i) The number of spotless days around the minimum of a solar cycle is statistically negatively correlated with the maximum strength of solar activity of that cycle. ii) The probability distribution of SA generally decreases monotonically with SA, but the distribution of SN generally increases first, then it decreases as a whole. The different probability distribution of SA and SN should strengthen their non-linear relation, and the correction factor [k] in the definition of SN may be one of the factors that cause the non-linearity. iii) The non-linear relation of SA and SN indeed exists statistically, and it is clearer during the maximum epoch of a solar cycle.

Examination about the Spatial Representation of PM2.5 Obtained from Limited Stations Using a Network Observation

NASA Astrophysics Data System (ADS)

Shi, X.; Zhao, C.

2017-12-01

Haze aerosol pollution has been a focus issue in China, and its characteristics is highly demanded. With limited observation sites, aerosol properties obtained from a single site is frequently used to represent the haze condition over a large domain, such as tens of kilometers. This could result in high uncertainties in the haze characteristics due to their spatial variation. Using a network observation from November 2015 to February 2016 over an urban city in North China with high spatial resolution, this study examines the spatial representation of ground site observations. A method is first developed to determine the representative area of measurements from limited stations. The key idea of this method is to determine the spatial variability of particulate matter with diameters less than 2.5 μm (PM2.5) concentration using a variance function in 2km x 2km grids. Based on the high spatial resolution (0.5km x 0.5km) measurements of PM2.5, the grids in which PM2.5 have high correlations and weak value differences are determined as the representation area of measurements at these grids. Note that the size representation area is not exactly a circle region. It shows that the size representation are for the study region and study period ranges from 0.25 km2 to 16.25 km2. The representation area varies with locations. For the 20 km x 20 km study region, 10 station observations would have a good representation of the PM2.5 observations obtained from current 169 stations at the four-month time scale.

Stabilisation of time-varying linear systems via Lyapunov differential equations

NASA Astrophysics Data System (ADS)

Zhou, Bin; Cai, Guang-Bin; Duan, Guang-Ren

2013-02-01

This article studies stabilisation problem for time-varying linear systems via state feedback. Two types of controllers are designed by utilising solutions to Lyapunov differential equations. The first type of feedback controllers involves the unique positive-definite solution to a parametric Lyapunov differential equation, which can be solved when either the state transition matrix of the open-loop system is exactly known, or the future information of the system matrices are accessible in advance. Different from the first class of controllers which may be difficult to implement in practice, the second type of controllers can be easily implemented by solving a state-dependent Lyapunov differential equation with a given positive-definite initial condition. In both cases, explicit conditions are obtained to guarantee the exponentially asymptotic stability of the associated closed-loop systems. Numerical examples show the effectiveness of the proposed approaches.

Auditory Evoked Potentials with Different Speech Stimuli: a Comparison and Standardization of Values

PubMed Central

Didoné, Dayane Domeneghini; Oppitz, Sheila Jacques; Folgearini, Jordana; Biaggio, Eliara Pinto Vieira; Garcia, Michele Vargas

2016-01-01

Introduction Long Latency Auditory Evoked Potentials (LLAEP) with speech sounds has been the subject of research, as these stimuli would be ideal to check individualś detection and discrimination. Objective The objective of this study is to compare and describe the values of latency and amplitude of cortical potentials for speech stimuli in adults with normal hearing. Methods The sample population included 30 normal hearing individuals aged between 18 and 32 years old with ontological disease and auditory processing. All participants underwent LLAEP search using pairs of speech stimuli (/ba/ x /ga/, /ba/ x /da/, and /ba/ x /di/. The authors studied the LLAEP using binaural stimuli at an intensity of 75dBNPS. In total, they used 300 stimuli were used (∼60 rare and 240 frequent) to obtain the LLAEP. Individuals received guidance to count the rare stimuli. The authors analyzed latencies of potential P1, N1, P2, N2, and P300, as well as the ampleness of P300. Results The mean age of the group was approximately 23 years. The averages of cortical potentials vary according to different speech stimuli. The N2 latency was greater for /ba/ x /di/ and P300 latency was greater for /ba/ x /ga/. Considering the overall average amplitude, it ranged from 5.35 and 7.35uV for different speech stimuli. Conclusion It was possible to obtain the values of latency and amplitude for different speech stimuli. Furthermore, the N2 component showed higher latency with the / ba / x / di / stimulus and P300 for /ba/ x / ga /. PMID:27096012

Impulsive Effects on Quasi-Synchronization of Neural Networks With Parameter Mismatches and Time-Varying Delay.

PubMed

Tang, Ze; Park, Ju H; Feng, Jianwen

2018-04-01

This paper is concerned with the exponential synchronization issue of nonidentically coupled neural networks with time-varying delay. Due to the parameter mismatch phenomena existed in neural networks, the problem of quasi-synchronization is thus discussed by applying some impulsive control strategies. Based on the definition of average impulsive interval and the extended comparison principle for impulsive systems, some criteria for achieving the quasi-synchronization of neural networks are derived. More extensive ranges of impulsive effects are discussed so that impulse could either play an effective role or play an adverse role in the final network synchronization. In addition, according to the extended formula for the variation of parameters with time-varying delay, precisely exponential convergence rates and quasi-synchronization errors are obtained, respectively, in view of different types impulsive effects. Finally, some numerical simulations with different types of impulsive effects are presented to illustrate the effectiveness of theoretical analysis.

Provisional hourly values of equatorial Dst for 1971

NASA Technical Reports Server (NTRS)

Sugiura, M.; Poros, D. J.

1972-01-01

Tables and plots of provisional hourly values of the equatorial Dst index for 1971 are given, a table of daily mean Dst values for 1971 is also provided. The base line values for the four observatories, Hermanus, Kakioka, Honolulu, and San Juan, were obtained from extrapolations using the coefficients for the secular variations determined for the previous years. Examining the Dst values for quiet days, the base lines so determined appear to be slightly low, so that the Dst index for quiet periods tends to be high.

Reference values and repeatability of the Schirmer tear tests I and II in domesticated, clinically normal dromedary camels (Camelus dromedarius).

PubMed

Marzok, Mohamed A; Badawy, Adel M; El-Khodery, Sabry A

2017-05-01

To determine the normal values and repeatability for Schirmer tear test (STT) in clinically normal dromedary camels and to analyze the influence of the age and gender on these values. Thirty clinically normal dromedary camels of different ages (calves, immature, and mature). Schirmer tear tests I and II were performed using commercial STT strips. Three measurements were obtained from each eye over three consecutive weeks, and the variance of these measurements was determined. Mean values and coefficient of variation of STT I and STT II for the right and left eyes varied significantly among camel groups (P < 0.05). For STT I, the most frequently recorded values were >14-18, > 22-26, and >30-34 mm/min in calves, immature camels, and mature camels, respectively. For STT II, however, the most frequently recorded values were 7-14, >10-18, and >26-30 mm/min, respectively. The interassay coefficients of variation were 1.7-14.4% and were significantly lower in mature camels than in calves and immature camels (P < 0.05). Age was positively correlated with STT I (r = 0.81) and STT II values (r = 0.88). No significant variations were found between genders. This preliminary study reports STT I and II values and repeatability in normal dromedary camels. This information may assist veterinary practitioners in complete ophthalmic examinations and in accurate diagnosis of ocular surface diseases affecting the tear film in this species. © 2016 American College of Veterinary Ophthalmologists.

Usability and reproducibility of tear meniscus values generated via swept-source optical coherence tomography and the slit lamp with a graticule method.

PubMed

Imamura, Hitoshi; Tabuchi, Hitoshi; Nakakura, Shunsuke; Nagasato, Daisuke; Baba, Hiroaki; Kiuchi, Yoshiaki

2018-04-01

To investigate the usability and the reproducibility of the tear meniscus values via swept-source optical coherence tomography (SS-OCT) and the conventional slit lamp microscope method with a graticule. The right eye was examined in 90 healthy adult subjects who were grouped according to age (group 1: 20-39 years; group 2: 40-59 years; group 3: ≥60 years). The tear meniscus height (TMH) and tear meniscus area were measured using SS-OCT and TMH by the slit lamp microscope method. The reproducibility of each method was calculated using intraclass correlation coefficients (ICCs) in additionally enrolled 30 healthy young subjects. We also evaluated TMH at 3 mm from the corneal center in both temporal and nasal directions using SS-OCT. The mean of the TMH values measured by SS-OCT was significantly higher than those measured by the slit lamp method (328 vs. 212 μm, P < 0.001, respectively). High reproducibility was observed for each method (ICC > 0.75 for both). No statistically significant differences were found in TMH among the age groups using both SS-OCT and slit lamp methods (P = 0.985, 0.380, respectively). TMH values at both sides of the corneal center were significantly smaller than those at the corneal center (P < 0.0001). TMH values obtained by the slit lamp method were lower than those obtained by SS-OCT. However, both methods yielded highly reproducible TMH measurements, suggesting that they are clinically useful. Tear meniscus values did not vary by age but by measurement points in our cohort.

Patients' Perspective on the Value of Medication Management Appointments.

PubMed

Cruz, Mario; Cruz, Robyn Flaum; Pincus, Harold Alan

2015-05-20

There is ongoing concern that psychiatric medication management appointments add little value to care. The present study attempted to address this concern by capturing depressed patients' views and opinions about the value of psychiatric medication management appointments. Seventy-eight semi-structured interviews were performed with white and African American depressed patients post medication management appointments. These interviews tapped patients' views and opinions about the value of attending medication management appointments. An iterative thematic analysis was performed. Patients reported greater appointment value when appointments included obtaining medications, discussing the need for medication changes or dose adjustments, and discussing the impact of medications on their illness. Additionally, greater appointment value was perceived by patients when there were non-medical conversations about life issues, immediate outcomes from the appointment such as motivation to continue in care, and specific qualities of providers that were appealing to patients. Patients' perceived value of psychiatric medication management appointments is complex. Though important patient outcomes are obtaining medicine and perceiving improvement in their mental health, there are other valued appointment and provider factors. Some of these other valued factors embedded within medication management appointments could have therapeutic properties. These findings have implications for future clinical research and service delivery.

The goal of value-based medicine analyses: comparability. The case for neovascular macular degeneration.

PubMed

Brown, Gary C; Brown, Melissa M; Brown, Heidi C; Kindermann, Sylvia; Sharma, Sanjay

2007-01-01

To evaluate the comparability of articles in the peer-reviewed literature assessing the (1) patient value and (2) cost-utility (cost-effectiveness) associated with interventions for neovascular age-related macular degeneration (ARMD). A search was performed in the National Library of Medicine database of 16 million peer-reviewed articles using the key words cost-utility, cost-effectiveness, value, verteporfin, pegaptanib, laser photocoagulation, ranibizumab, and therapy. All articles that used an outcome of quality-adjusted life-years (QALYs) were studied in regard to (1) percent improvement in quality of life, (2) utility methodology, (3) utility respondents, (4) types of costs included (eg, direct healthcare, direct nonhealthcare, indirect), (5) cost bases (eg, Medicare, National Health Service in the United Kingdom), and (6) study cost perspective (eg, government, societal, third-party insurer). To qualify as a value-based medicine analysis, the patient value had to be measured using the outcome of the QALYs conferred by respective interventions. As with value-based medicine analyses, patient-based time tradeoff utility analysis had to be utilized, patient utility respondents were necessary, and direct medical costs were used. Among 21 cost-utility analyses performed on interventions for neovascular macular degeneration, 15 (71%) met value-based medicine criteria. The 6 others (29%) were not comparable owing to (1) varying utility methodology, (2) varying utility respondents, (3) differing costs utilized, (4) differing cost bases, and (5) varying study perspectives. Among value-based medicine studies, laser photocoagulation confers a 4.4% value gain (improvement in quality of life) for the treatment of classic subfoveal choroidal neovascularization. Intravitreal pegaptanib confers a 5.9% value gain (improvement in quality of life) for classic, minimally classic, and occult subfoveal choroidal neovascularization, and photodynamic therapy with verteporfin confers

THE GOAL OF VALUE-BASED MEDICINE ANALYSES: COMPARABILITY. THE CASE FOR NEOVASCULAR MACULAR DEGENERATION

PubMed Central

Brown, Gary C.; Brown, Melissa M.; Brown, Heidi C.; Kindermann, Sylvia; Sharma, Sanjay

2007-01-01

Purpose To evaluate the comparability of articles in the peer-reviewed literature assessing the (1) patient value and (2) cost-utility (cost-effectiveness) associated with interventions for neovascular age-related macular degeneration (ARMD). Methods A search was performed in the National Library of Medicine database of 16 million peer-reviewed articles using the key words cost-utility, cost-effectiveness, value, verteporfin, pegaptanib, laser photocoagulation, ranibizumab, and therapy. All articles that used an outcome of quality-adjusted life-years (QALYs) were studied in regard to (1) percent improvement in quality of life, (2) utility methodology, (3) utility respondents, (4) types of costs included (eg, direct healthcare, direct nonhealthcare, indirect), (5) cost bases (eg, Medicare, National Health Service in the United Kingdom), and (6) study cost perspective (eg, government, societal, third-party insurer). To qualify as a value-based medicine analysis, the patient value had to be measured using the outcome of the QALYs conferred by respective interventions. As with value-based medicine analyses, patient-based time tradeoff utility analysis had to be utilized, patient utility respondents were necessary, and direct medical costs were used. Results Among 21 cost-utility analyses performed on interventions for neovascular macular degeneration, 15 (71%) met value-based medicine criteria. The 6 others (29%) were not comparable owing to (1) varying utility methodology, (2) varying utility respondents, (3) differing costs utilized, (4) differing cost bases, and (5) varying study perspectives. Among value-based medicine studies, laser photocoagulation confers a 4.4% value gain (improvement in quality of life) for the treatment of classic subfoveal choroidal neovascularization. Intravitreal pegaptanib confers a 5.9% value gain (improvement in quality of life) for classic, minimally classic, and occult subfoveal choroidal neovascularization, and photodynamic therapy

Watermarking scheme based on singular value decomposition and homomorphic transform

NASA Astrophysics Data System (ADS)

Verma, Deval; Aggarwal, A. K.; Agarwal, Himanshu

2017-10-01

A semi-blind watermarking scheme based on singular-value-decomposition (SVD) and homomorphic transform is pro-posed. This scheme ensures the digital security of an eight bit gray scale image by inserting an invisible eight bit gray scale wa-termark into it. The key approach of the scheme is to apply the homomorphic transform on the host image to obtain its reflectance component. The watermark is embedded into the singular values that are obtained by applying the singular value decomposition on the reflectance component. Peak-signal-to-noise-ratio (PSNR), normalized-correlation-coefficient (NCC) and mean-structural-similarity-index-measure (MSSIM) are used to evaluate the performance of the scheme. Invisibility of watermark is ensured by visual inspection and high value of PSNR of watermarked images. Presence of watermark is ensured by visual inspection and high values of NCC and MSSIM of extracted watermarks. Robustness of the scheme is verified by high values of NCC and MSSIM for attacked watermarked images.

Correlation between radio-induced lymphocyte apoptosis measurements obtained from two French centres.

PubMed

Mirjolet, C; Merlin, J L; Dalban, C; Maingon, P; Azria, D

2016-07-01

In the era of modern treatment delivery, increasing the dose delivered to the target to improve local control might be modulated by the patient's intrinsic radio-sensitivity. A predictive assay based on radio-induced lymphocyte apoptosis quantification highlighted the significant correlation between CD4 and CD8 T-lymphocyte apoptosis and grade 2 or 3 radiation-induced late toxicities. By conducting this assay at several technical platforms, the aim of this study was to demonstrate that radio-induced lymphocyte apoptosis values obtained from two different platforms were comparable. For 25 patients included in the PARATOXOR trial running in Dijon the radio-induced lymphocyte apoptosis results obtained from the laboratory of Montpellier (IRCM, Inserm U1194, France), considered as the reference (referred to as Lab 1), were compared with those from the laboratory located at the Institut de cancérologie de Lorraine (ICL, France), referred to as Lab 2. Different statistical methods were used to measure the agreement between the radio-induced lymphocyte apoptosis data from the two laboratories (quantitative data). The Bland-Altman plot was used to identify potential bias. All statistical tests demonstrated good agreement between radio-induced lymphocyte apoptosis values obtained from both sites and no major bias was identified. Since radio-induced lymphocyte apoptosis values, which predict tolerance to radiotherapy, could be assessed by two laboratories and showed a high level of robustness and consistency, we can suggest that this assay be extended to any laboratories that use the same technique. Copyright © 2016 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

Monopoly models with time-varying demand function

NASA Astrophysics Data System (ADS)

Cavalli, Fausto; Naimzada, Ahmad

2018-05-01

We study a family of monopoly models for markets characterized by time-varying demand functions, in which a boundedly rational agent chooses output levels on the basis of a gradient adjustment mechanism. After presenting the model for a generic framework, we analytically study the case of cyclically alternating demand functions. We show that both the perturbation size and the agent's reactivity to profitability variation signals can have counterintuitive roles on the resulting period-2 cycles and on their stability. In particular, increasing the perturbation size can have both a destabilizing and a stabilizing effect on the resulting dynamics. Moreover, in contrast with the case of time-constant demand functions, the agent's reactivity is not just destabilizing, but can improve stability, too. This means that a less cautious behavior can provide better performance, both with respect to stability and to achieved profits. We show that, even if the decision mechanism is very simple and is not able to always provide the optimal production decisions, achieved profits are very close to those optimal. Finally, we show that in agreement with the existing empirical literature, the price series obtained simulating the proposed model exhibit a significant deviation from normality and large volatility, in particular when underlying deterministic dynamics become unstable and complex.

Hematologic values of the endangered San Joaquin kit fox, Vulpes macrotis mutica

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

McCue, P.M.; O'Farrell, T.P.

1986-01-01

Between 1981 and 1982 a total of 102 blood samples was collected from 91 San Joaquin kit foxes, Vulpes macrotis mutica, won the US Department of Energy's Naval Petroleum Reserve No. 1 (Elk Hills), in western Kern County, California. The goal of the study was to establish normal blood parameters for this endangered species and to determine whether changes in them could be used to assess the possible effects of petroleum developments on foxes. Adult foxes had the following average hematological characteristics: RBC, 8.4 x 10/sup 6/ cells/..mu..l; Hb, 14.9 g/dl; PCV, 46.9%; MCV, 56.4 fl; MCH, 18.2 pg; MCHC,more » 32.0 g/dl; and WBC, 6900/..mu..l. None of the parameters differed significantly between the sexes. RBC, Hb, PCV, MCV, and MCHC varied as a function of age for puppies between three and six months of age. The highest values of MCV and MCH were obtained in summer, 1982, and the highest value of MCHC was obtained in winter, 1981-1982. These were the only parameters that appeared to change with season. None of the blood parameters appeared to be affected by petroleum developments. Hematological data for kit foxes, coyotes, and wolves confirmed a previously published observation that within mammalian families RBC is inversely correlated with body weight, and that MCV is directly correlated with body weight. It was speculated that it was an adaptive advantage for kit foxes having a high weight-specific metabolic rate to have evolved a high RBC and low MCV, allowing increased oxygen transport and exchange, while PCV was maintained relatively constant, avoiding hemoconcentration and increased viscosity of blood. 33 refs., 1 fig., 6 tabs.« less

Time-varying sliding-coefficient-based decoupled terminal sliding-mode control for a class of fourth-order systems.

PubMed

Bayramoglu, Husnu; Komurcugil, Hasan

2014-07-01

A time-varying sliding-coefficient-based decoupled terminal sliding mode control strategy is presented for a class of fourth-order systems. First, the fourth-order system is decoupled into two second-order subsystems. The sliding surface of each subsystem was designed by utilizing time-varying coefficients. Then, the control target of one subsystem to another subsystem was embedded. Thereafter, a terminal sliding mode control method was utilized to make both subsystems converge to their equilibrium points in finite time. The simulation results on the inverted pendulum system demonstrate that the proposed method exhibits a considerable improvement in terms of a faster dynamic response and lower IAE and ITAE values as compared with the existing decoupled control methods. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

High historical values of foEs—Reality or artefact?

NASA Astrophysics Data System (ADS)

Laštovička, J.; Boška, J.; Burešová, D.; Kouba, D.

2012-01-01

Very high values of foEs had sometimes been reported in the past. These values, as well as all other ionogram-scaled values, had been derived from ionograms under the assumption of the vertical reflection of ordinary mode of sounding radio waves. In the past it was impossible to check the validity of this assumption. However, modern digisondes determine clearly the oblique or extraordinary mode reflections. To test the assumption of the vertical reflection of ordinary mode for high values of foEs, seven summers (June 2004-August 2010) from a midlatitude station Pruhonice are chosen. All hourly values of foEs≥6.0 MHz are selected from this data set, altogether 282 values. In 90% of cases the “classical” way of evaluation of foEs provides values higher than “true” values from modern digisonde (average difference about 1 MHz). 38% of “classical” foEs are oblique reflections, which however do not occur in direction perpendicular to geomagnetic field. The occurrence of high values of foEs varies very much from year to year between 0 and 130 events per year. As for diurnal variation, a pronounced maximum occurs at ˜10:00LT and 16:00LT (secondary), and a minimum after midnight.

Assessment of a surface-layer parameterization scheme in an atmospheric model for varying meteorological conditions

NASA Astrophysics Data System (ADS)

Anurose, T. J.; Bala Subrahamanyam, D.

2014-06-01

The performance of a surface-layer parameterization scheme in a high-resolution regional model (HRM) is carried out by comparing the model-simulated sensible heat flux (H) with the concurrent in situ measurements recorded at Thiruvananthapuram (8.5° N, 76.9° E), a coastal station in India. With a view to examining the role of atmospheric stability in conjunction with the roughness lengths in the determination of heat exchange coefficient (CH) and H for varying meteorological conditions, the model simulations are repeated by assigning different values to the ratio of momentum and thermal roughness lengths (i.e. z0m/z0h) in three distinct configurations of the surface-layer scheme designed for the present study. These three configurations resulted in differential behaviour for the varying meteorological conditions, which is attributed to the sensitivity of CH to the bulk Richardson number (RiB) under extremely unstable, near-neutral and stable stratification of the atmosphere.

Adaptive value of sex in microbial pathogens.

PubMed

Michod, Richard E; Bernstein, Harris; Nedelcu, Aurora M

2008-05-01

Explaining the adaptive value of sex is one of the great outstanding problems in biology. The challenge comes from the difficulty in identifying the benefits provided by sex, which must outweigh the substantial costs of sex. Here, we consider the adaptive value of sex in viruses, bacteria and fungi, and particularly the information available on the adaptive role of sex in pathogenic microorganisms. Our general theme is that the varied aspects of sex in pathogens illustrate the varied issues surrounding the evolution of sex generally. These include, the benefits of sex (in the short- and long-term), as well as the costs of sex (both to the host and to the pathogen). For the benefits of sex (that is, its adaptive value), we consider three hypotheses: (i) sex provides for effective and efficient recombinational repair of DNA damages, (ii) sex provides DNA for food, and (iii) sex produces variation and reduces genetic associations among alleles under selection. Although the evolution of sex in microbial pathogens illustrates these general issues, our paper is not a general review of theories for the evolution of sex in all organisms. Rather, we focus on the adaptive value of sex in microbial pathogens and conclude that in terms of short-term benefits, the DNA repair hypothesis has the most support and is the most generally applicable hypothesis in this group. In particular, recombinational repair of DNA damages may substantially benefit pathogens when challenged by the oxidative defenses of the host. However, in the long-term, sex may help get rid of mutations, increase the rate of adaptation of the population, and, in pathogens, may infrequently create new infective strains. An additional general issue about sex illustrated by pathogens is that some of the most interesting consequences of sex are not necessarily the reasons for which sex evolved. For example, antibiotic resistance may be transferred by bacterial sex, but this transfer is probably not the reason sex

A study of thematic content in hospital mission statements: a question of values.

PubMed

Williams, Jaime; Smythe, William; Hadjistavropoulos, Thomas; Malloy, David C; Martin, Ronald

2005-01-01

We examined the content of Canadian hospital mission statements using thematic content analysis. The mission statements that we studied varied in terms of both content and length. Although there was some content related to goals designed to ensure organizational visibility, survival, and competitiveness, the domain of values predominated over our entire coding structure. The primary value-related theme that emerged concerned the importance of patient care.

Scalar discrete nonlinear multipoint boundary value problems

NASA Astrophysics Data System (ADS)

Rodriguez, Jesus; Taylor, Padraic

2007-06-01

In this paper we provide sufficient conditions for the existence of solutions to scalar discrete nonlinear multipoint boundary value problems. By allowing more general boundary conditions and by imposing less restrictions on the nonlinearities, we obtain results that extend previous work in the area of discrete boundary value problems [Debra L. Etheridge, Jesus Rodriguez, Periodic solutions of nonlinear discrete-time systems, Appl. Anal. 62 (1996) 119-137; Debra L. Etheridge, Jesus Rodriguez, Scalar discrete nonlinear two-point boundary value problems, J. Difference Equ. Appl. 4 (1998) 127-144].

New Passivity Criteria for Fuzzy Bam Neural Networks with Markovian Jumping Parameters and Time-Varying Delays

NASA Astrophysics Data System (ADS)

Vadivel, P.; Sakthivel, R.; Mathiyalagan, K.; Thangaraj, P.

2013-02-01

This paper addresses the problem of passivity analysis issue for a class of fuzzy bidirectional associative memory (BAM) neural networks with Markovian jumping parameters and time varying delays. A set of sufficient conditions for the passiveness of the considered fuzzy BAM neural network model is derived in terms of linear matrix inequalities by using the delay fractioning technique together with the Lyapunov function approach. In addition, the uncertainties are inevitable in neural networks because of the existence of modeling errors and external disturbance. Further, this result is extended to study the robust passivity criteria for uncertain fuzzy BAM neural networks with time varying delays and uncertainties. These criteria are expressed in the form of linear matrix inequalities (LMIs), which can be efficiently solved via standard numerical software. Two numerical examples are provided to demonstrate the effectiveness of the obtained results.

Analysis of the stability of nonlinear suspension system with slow-varying sprung mass under dual-excitation

NASA Astrophysics Data System (ADS)

Yao, Jun; Zhang, Jinqiu; Zhao, Mingmei; Li, Xin

2018-07-01

This study investigated the stability of vibration in a nonlinear suspension system with slow-varying sprung mass under dual-excitation. A mathematical model of the system was first established and then solved using the multi-scale method. Finally, the amplitude-frequency curve of vehicle vibration, the solution's stable region and time-domain curve in Hopf bifurcation were derived. The obtained results revealed that an increase in the lower excitation would reduce the system's stability while an increase in the upper excitation can make the system more stable. The slow-varying sprung mass will change the system's damping from negative to positive, leading to the appearance of limit cycle and Hopf bifurcation. As a result, the vehicle's vibration state is forced to change. The stability of this system is extremely fragile under the effect of dynamic Hopf bifurcation as well as static bifurcation.

Transfer factors and effective half-lives of (134)Cs and (137)Cs in different environmental sample types obtained from Northern Finland: case Fukushima accident.

PubMed

Koivurova, Matias; Leppänen, Ari-Pekka; Kallio, Antti

2015-08-01

The Fukushima NPP accident caused a small but detectable cesium fallout in northern Finland, of the order of 1 Bq/m(2). This fallout transferred further to soil, water, flora and fauna. By using modern HPGe detector systems traces of (134)Cs from the Fukushima fallout were observed in various samples of biota. In northern Finland different types of environmental samples such as reindeer meat, berries, fish, lichens and wolf were collected during 2011-2013. The observed (134)Cs concentrations varied from 0.1 Bq/kg to a few Bq/kg. By using the known (134)Cs/(137)Cs ratio observed in Fukushima fallout the increase of the Fukushima accident to the (137)Cs concentrations was found to vary from 0.06 % to 6.9 % depending on the sample type. The aggregated transfer factors (Tag) and effective half-lives (Teff) for (134)Cs and (137)Cs were also determined and then compared with known values found from earlier studies which are calculated based on the fallout from the Chernobyl accident. Generally, the Tag and Teff values determined in this study were found to agree with the values found in the earlier studies. The Teff values were sample-type specific and were found to vary from 0.91 to 2.1 years for (134)Cs and the estimates for (137)Cs ranged between 1.6 and 19 years. Interestingly, the ground lichens had the longest Teff whereas the beard lichen had the shortest. In fauna, highest Tag values were determined for wolf meat ranging between 1.0 and 2.2 m(2)/kg. In flora, the highest Tag values were determined for beard lichens, ranging from 1.9 m(2)/kg to 3.5 m(2)/kg. Copyright © 2015 Elsevier Ltd. All rights reserved.

Boys, girls, and the school cultural environment: Teachers' judgment and students' values.

PubMed

Aelenei, Cristina; Darnon, Céline; Martinot, Delphine

2017-01-01

Due to gender socialization, girls are more likely to endorse self-transcendence values (e.g., helping people) compared to boys, whereas boys are more likely to endorse self-enhancement values (e.g., wanting to be in charge) compared to girls. In two studies, we investigated teachers' judgment regarding the display of these values in school and students' endorsement of the self-transcendence and self-enhancement values in two contexts: home and school. In Study 1 (N = 240), teachers evaluated a student perceived as strongly endorsing the self-transcendence values more positively compared to a student perceived as strongly endorsing the self-enhancement values, regardless of the student's gender. In Study 2 (N = 151), boys endorsed the self-enhancement values more than the self-transcendence values at home, whereas the opposite occurred in the school context. Girls did not vary across contexts, endorsing the self-transcendence values more than the self-enhancement values in both contexts. Possible consequences on boys' school-related outcomes are discussed.

High speed Infrared imaging method for observation of the fast varying temperature phenomena

NASA Astrophysics Data System (ADS)

Moghadam, Reza; Alavi, Kambiz; Yuan, Baohong

With new improvements in high-end commercial R&D camera technologies many challenges have been overcome for exploring the high-speed IR camera imaging. The core benefits of this technology is the ability to capture fast varying phenomena without image blur, acquire enough data to properly characterize dynamic energy, and increase the dynamic range without compromising the number of frames per second. This study presents a noninvasive method for determining the intensity field of a High Intensity Focused Ultrasound Device (HIFU) beam using Infrared imaging. High speed Infrared camera was placed above the tissue-mimicking material that was heated by HIFU with no other sensors present in the HIFU axial beam. A MATLAB simulation code used to perform a finite-element solution to the pressure wave propagation and heat equations within the phantom and temperature rise to the phantom was computed. Three different power levels of HIFU transducers were tested and the predicted temperature increase values were within about 25% of IR measurements. The fundamental theory and methods developed in this research can be used to detect fast varying temperature phenomena in combination with the infrared filters.

Proximate analyses and predicting HHV of chars obtained from cocracking of petroleum vacuum residue with coal, plastics and biomass.

PubMed

Ahmaruzzaman, M

2008-07-01

Higher heating value (HHV) and analysis of chars obtained from cocracking of petroleum vacuum residue (XVR) with coal (SC), biomass (BG, CL) and plastics (PP, PS, BL) are important which define the energy content and determine the clean and efficient use of these chars. The main aim of the present study is to analyze the char obtained from cocracking in terms of their proximate analysis data and determination of the HHV of the chars. The char obtained from XVR+PP cocracking showed a HHV of 32.84 MJ/kg, whereas that from CL cracking showed a HHV of 18.52 MJ/kg. The experimentally determined heating values of the char samples obtained from cocracking have been correlated with the theoretical equation based on proximate analysis data. There exists a variety of correlations for predicting HHV from proximate analysis of fuels. Based upon proximate analysis data, the models were tested. The best results show coefficient of determination (R2) of 0.965 and average absolute and bias error of 3.07% and 0.41%, respectively. The heating values obtained from the model were in good agreement with that obtained by experiment. Proximate analysis of the chars obtained from the cocracking of XVR with coal, biomass and plastics showed that there exists a definite interaction of the reactive species, when they were cocracked together.

The initial value problem in Lagrangian drift kinetic theory

NASA Astrophysics Data System (ADS)

Burby, J. W.

2016-06-01

> Existing high-order variational drift kinetic theories contain unphysical rapidly varying modes that are not seen at low orders. These unphysical modes, which may be rapidly oscillating, damped or growing, are ushered in by a failure of conventional high-order drift kinetic theory to preserve the structure of its parent model's initial value problem. In short, the (infinite dimensional) system phase space is unphysically enlarged in conventional high-order variational drift kinetic theory. I present an alternative, `renormalized' variational approach to drift kinetic theory that manifestly respects the parent model's initial value problem. The basic philosophy underlying this alternate approach is that high-order drift kinetic theory ought to be derived by truncating the all-orders system phase-space Lagrangian instead of the usual `field particle' Lagrangian. For the sake of clarity, this story is told first through the lens of a finite-dimensional toy model of high-order variational drift kinetics; the analogous full-on drift kinetic story is discussed subsequently. The renormalized drift kinetic system, while variational and just as formally accurate as conventional formulations, does not support the troublesome rapidly varying modes.

Effect of calcium in assay medium on D value of Bacillus stearothermophilus ATCC 7953 spores.

PubMed

Sasaki, K; Shintani, H; Itoh, J; Kamogawa, T; Kajihara, Y

2000-12-01

The D value of commercial biological indicator spore strips using Bacillus stearothermophilus ATCC 7953 was increased by higher calcium concentrations in assay media. The calcium concentration in assay media varied among the manufacturers. The calcium concentration in assay media is an important factor to consider to minimize the variation of D value.

Redox potential - field measurements - meassured vs. expected values

NASA Astrophysics Data System (ADS)

Stavělová, Monika; Kovář, Martin

2016-04-01

Oxidation and reduction (redox) potential is an important and theoretically very well defined parameter and can be calculated accurately. Its value is determinative for management of many electrochemical processes, chemical redox technologies as well as biotechnologies. To measure the redox value that would correspond with the accuracy level of theoretical calculations in field or operational conditions is however nearly impossible. Redox is in practice measured using combined argentochloride electrode with subsequent value conversion to standard hydrogen electrode (EH). Argentochloride electrode does not allow for precise calibration. Prior to the measurement the accuracy of measurement of particular electrode can only be verified in comparative/control solution with value corresponding with oxic conditions (25°C: +220 mV argentochloride electrode, i.e.. +427 mV after conversion to EH). A commercial product of stabile comparative solution for anoxic conditions is not available and therefore not used in every day practice - accuracy of negative redox is not verified. In this presentation results of two tests will be presented: a) monitoring during dynamic groundwater sampling from eight monitoring wells at a site contaminated by chlorinated ethenes (i.e. post-oxic to anoxic conditions) and b) laboratory test of groundwater contaminated by arsenic from two sites during reaction with highly oxidized compounds of iron (ferrates) - i.e. strongly oxic conditions. In both tests a simultaneous measurement by four argentochloride electrodes was implemented - all four electrodes were prior to the test maintained expertly. The redox values of testing electrodes in a comparative solution varied by max. 6 mV. The redox values measured by four electrodes in both anoxic and oxic variant varied by tens to a hundred mV, while with growing time of test the variance of measured redox values increased in both oxic and anoxic variant. Therefore the interpretation of measured redox

BLOOD CHEMISTRY AND HEMATOLOGY VALUES IN HEALTHY AND REHABILITATED ROUGH-TOOTHED DOLPHINS ( STENO BREDANENSIS).

PubMed

Manire, Charles A; Reiber, C Melanie; Gaspar, Cécile; Rhinehart, Howard L; Byrd, Lynne; Sweeney, Jay; West, Kristi L

2018-01-01

Rehabilitation efforts for live stranded marine mammals are guided by diagnostic measures of blood chemistry and hematology parameters obtained from each individual undergoing treatment. Despite the widespread use of blood parameters, reference values are not available in the literature from healthy rough-toothed dolphins ( Steno bredanensis) with which to infer the health status of an animal. We examined serum or plasma chemistry and hematology data from 17 rough-toothed dolphins either housed at Dolphin Quest French Polynesia or during their rehabilitation at the Dolphin and Whale Hospital in Sarasota, Florida, US between 1994 and 2005. Blood parameters were compared among healthy animals, rehabilitation animals that were eventually released, and rehabilitation animals that died. This study indicated significant differences in many blood parameters for the poorly known rough-toothed dolphin that are likely to vary between healthy and sick animals. These included aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, bicarbonate, and globulins, which were greater in sick dolphins, and alkaline phosphatase and total protein which were greater in healthy individuals. Total white blood cell counts were lower in healthy animals as were the absolute numbers of neutrophils, monocytes, and eosinophils. Analysis of first blood sample levels for glucose, sodium, and erythrocyte sedimentation rate may have value for triage and prognostic evaluation.

Dynamic Factor Analysis Models with Time-Varying Parameters

ERIC Educational Resources Information Center

Chow, Sy-Miin; Zu, Jiyun; Shifren, Kim; Zhang, Guangjian

2011-01-01

Dynamic factor analysis models with time-varying parameters offer a valuable tool for evaluating multivariate time series data with time-varying dynamics and/or measurement properties. We use the Dynamic Model of Activation proposed by Zautra and colleagues (Zautra, Potter, & Reich, 1997) as a motivating example to construct a dynamic factor…

Everyday value conflicts and integrative complexity of thought.

PubMed

Myyry, Liisa

2002-12-01

This study examined the value pluralism model in everyday value conflicts, and the effect of issue context on complexity of thought. According to the cognitive manager model we hypothesized that respondents would obtain a higher level of integrative complexity on personal issues that on professional and general issues. We also explored the relations of integrative complexity to value priorities, measured by the Schwartz Value Survey, and to emotional empathy. The value pluralism model was not supported by the data collected from 126 university students from social science, business and technology. The cognitive manager model was partially confirmed by data from females but not from males. Concerning value priorities, more complex respondents had higher regard for self-transcendence values, and less complex respondents for self-enhancement values Emotional empathy was also significantly related to complexity score.

The Varied Roles of Notch in Cancer

PubMed Central

Aster, Jon C.; Pear, Warren S.; Blacklow, Stephen C.

2018-01-01

Notch receptors influence cellular behavior by participating in a seemingly simple signaling pathway, but outcomes produced by Notch signaling are remarkably varied depending on signal dose and cell context. Here, after briefly reviewing new insights into physiologic mechanisms of Notch signaling in healthy tissues and defects in Notch signaling that contribute to congenital disorders and viral infection, we discuss the varied roles of Notch in cancer, focusing on cell autonomous activities that may be either oncogenic or tumor suppressive. PMID:27959635

Two-dimensional dynamic stall as simulated in a varying freestream

NASA Technical Reports Server (NTRS)

Pierce, G. A.; Kunz, D. L.; Malone, J. B.

1978-01-01

A low speed wind tunnel equipped with a axial gust generator to simulate the aerodynamic environment of a helicopter rotor was used to study the dynamic stall of a pitching blade in an effort to ascertain to what extent harmonic velocity perturbations in the freestream affect dynamic stall. The aerodynamic moment on a two dimensional, pitching blade model in both constant and pulsating airstream was measured. An operational analog computer was used to perform on-line data reduction and plots of moment versus angle of attack and work done by the moment were obtained. The data taken in the varying freestream were then compared to constant freestream data and to the results of two analytical methods. These comparisons show that the velocity perturbations have a significant effect on the pitching moment which can not be consistently predicted by the analytical methods, but had no drastic effect on the blade stability.

Global value chains: Building blocks and network dynamics

NASA Astrophysics Data System (ADS)

Tsekeris, Theodore

2017-12-01

The paper employs measures and tools from complex network analysis to enhance the understanding and interpretation of structural characteristics pertaining to the Global Value Chains (GVCs) during the period 1995-2011. The analysis involves the country, sector and country-sector value chain networks to identify main drivers of structural change. The results indicate significant intertemporal changes, mirroring the increased globalization in terms of network size, strength and connectivity. They also demonstrate higher clustering and increased concentration of the most influential countries and country-sectors relative to all others in the GVC network, with the geographical dimension to prevail over the sectoral dimension in the formation of value chains. The regionalization and less hierarchical organization drive country-sector production sharing, while the sectoral value chain network has become more integrated and more competitive over time. The findings suggest that the impact of country-sector policies and/or shocks may vary with the own-group and network-wide influence of each country, take place in multiple geographical scales, as GVCs have a block structure, and involve time dynamics.

Synchronization of a Class of Switched Neural Networks with Time-Varying Delays via Nonlinear Feedback Control.

PubMed

Wang, Leimin; Shen, Yi; Zhang, Guodong

2016-10-01

This paper is concerned with the synchronization problem for a class of switched neural networks (SNNs) with time-varying delays. First, a new crucial lemma which includes and extends the classical exponential stability theorem is constructed. Then by using the lemma, new algebraic criteria of ψ -type synchronization (synchronization with general decay rate) for SNNs are established via the designed nonlinear feedback control. The ψ -type synchronization which is in a general framework is obtained by introducing a ψ -type function. It contains exponential synchronization, polynomial synchronization, and other synchronization as its special cases. The results of this paper are general, and they also complement and extend some previous results. Finally, numerical simulations are carried out to demonstrate the effectiveness of the obtained results.

Perspectives on woody biomass fuel value and specifications in Alabama

Treesearch

Dana Mitchell

2006-01-01

Pulp and paper mills in Alabama buy woody biomass but the specifications required by the mills vary and are not widely known. Some characteristics of woody biomass that are often included in mill specifications include size, species, ash and moisture content. These characteristics are briefly reviewed in reference to how they impact the energy value, physical handling...

Local regularity for time-dependent tug-of-war games with varying probabilities

NASA Astrophysics Data System (ADS)

Parviainen, Mikko; Ruosteenoja, Eero

2016-07-01

We study local regularity properties of value functions of time-dependent tug-of-war games. For games with constant probabilities we get local Lipschitz continuity. For more general games with probabilities depending on space and time we obtain Hölder and Harnack estimates. The games have a connection to the normalized p (x , t)-parabolic equation ut = Δu + (p (x , t) - 2) Δ∞N u.

Effect of Calcium in Assay Medium on D Value of Bacillus stearothermophilus ATCC 7953 Spores

PubMed Central

Sasaki, Koichi; Shintani, Hideharu; Itoh, Junpei; Kamogawa, Takuji; Kajihara, Yousei

2000-01-01

The D value of commercial biological indicator spore strips using Bacillus stearothermophilus ATCC 7953 was increased by higher calcium concentrations in assay media. The calcium concentration in assay media varied among the manufacturers. The calcium concentration in assay media is an important factor to consider to minimize the variation of D value. PMID:11097939

[Influence of surface roughness on degree of polarization of biotite plagioclase gneiss varying with viewing angle].

PubMed

Xiang, Yun; Yan, Lei; Zhao, Yun-sheng; Gou, Zhi-yang; Chen, Wei

2011-12-01

Polarized reflectance is influenced by such factors as its physical and chemical properties, the viewing geometry composed of light incident zenith, viewing zenith and viewing azimuth relative to light incidence, surface roughness and texture, surface density, detection wavelengths, polarization phase angle and so on. In the present paper, the influence of surface roughness on the degree of polarization (DOP) of biotite plagioclase gneiss varying with viewing angle was inquired and analyzed quantitatively. The polarized spectra were measured by ASD FS3 spectrometer on the goniometer located in Northeast Normal University. When the incident zenith angle was fixed at 50 degrees, it was showed that on the rock surfaces with different roughness, in the specular reflection direction, the DOP spectrum within 350-2500 nm increased to the highest value first, and then began to decline varying with viewing zenith angle from 0 degree to 80 degrees. The characterized band (520 +/- 10) nm was picked out for further analysis. The correlation analysis between the peak DOP value of zenith and surface roughness showed that they are in a power function relationship, with the regression equation: y = 0.604x(-0.297), R2 = 0.985 4. The correlation model of the angle where the peak is in and the surface roughness is y = 3.4194x + 51.584, y < 90 degrees , R2 = 0.8177. With the detecting azimuth farther away from 180 degrees azimuth where the maximum DOP exists, the DOP lowers gradually and tends to 0. In the detection azimuth 180 dgrees , the correlation analysis between the peak values of DOP on the (520 =/- 10) nm band for five rocks and their surface roughness indicates a power function, with the regression equation being y = 0.5822x(-0.333), R2 = 0.9843. F tests of the above regression models indicate that the peak value and its corresponding viewing angle correlate much with surface roughness. The study provides a theoretical base for polarization remote sensing, and impels the

[Morphometric and stereologic nuclear values obtained from the study of a population suffering from nasopharyngeal carcinoma].

PubMed

Pérez Plasencia, D; Flores Corral, T; Urrutia Avisrror, M; Santa Cruz Ruiz, S; Benito González, J; Mateos Pérez, M M; Gómez González, J L

2002-01-01

Computer nuclear morphometry and stereology are attractive methods because its objectivity and cheapness allowing histologic diagnosis when identifying minimal variations respectively the normality and also detect negligible disparities between anormal cells which could escape to the assessment of the pathologist. We present the data gained from several morphogenic and stereologic parameters resulting of measurements of tumoral cells procured from 40 patients with nasopharyngeal carcinomata. Middle values have been: nuclear area 27.70 microns 2; nuclear perimeter 20.80 microns; nuclear factor of form 0.81 microns; nuclear outline index 4.01; nuclear orientation angle 87.29 degrees; nuclear ellipsiticity 704.14; nuclear regularity 61.83; middle lineal length 4.30, middle linear distance 107.94; and nuclear volume 118.80 microns 3. Our series is the largest studied till now of all found in the literature. Comparison our data with those of previous publications.

Species richness alone does not predict cultural ecosystem service value

PubMed Central

Graves, Rose A.; Pearson, Scott M.; Turner, Monica G.

2017-01-01

Many biodiversity-ecosystem services studies omit cultural ecosystem services (CES) or use species richness as a proxy and assume that more species confer greater CES value. We studied wildflower viewing, a key biodiversity-based CES in amenity-based landscapes, in Southern Appalachian Mountain forests and asked (i) How do aesthetic preferences for wildflower communities vary with components of biodiversity, including species richness?; (ii) How do aesthetic preferences for wildflower communities vary across psychographic groups?; and (iii) How well does species richness perform as an indicator of CES value compared with revealed social preferences for wildflower communities? Public forest visitors (n = 293) were surveyed during the summer of 2015 and asked to choose among images of wildflower communities in which flower species richness, flower abundance, species evenness, color diversity, and presence of charismatic species had been digitally manipulated. Aesthetic preferences among images were unrelated to species richness but increased with more abundant flowers, greater species evenness, and greater color diversity. Aesthetic preferences were consistent across psychographic groups and unaffected by knowledge of local flora or value placed on wildflower viewing. When actual wildflower communities (n = 54) were ranked based on empirically measured flower species richness or wildflower viewing utility based on multinomial logit models of revealed preferences, rankings were broadly similar. However, designation of hotspots (CES values above the median) based on species richness alone missed 27% of wildflower viewing utility hotspots. Thus, conservation priorities for sustaining CES should incorporate social preferences and consider multiple dimensions of biodiversity that underpin CES supply. PMID:28320953

Species richness alone does not predict cultural ecosystem service value.

PubMed

Graves, Rose A; Pearson, Scott M; Turner, Monica G

2017-04-04

Many biodiversity-ecosystem services studies omit cultural ecosystem services (CES) or use species richness as a proxy and assume that more species confer greater CES value. We studied wildflower viewing, a key biodiversity-based CES in amenity-based landscapes, in Southern Appalachian Mountain forests and asked ( i ) How do aesthetic preferences for wildflower communities vary with components of biodiversity, including species richness?; ( ii ) How do aesthetic preferences for wildflower communities vary across psychographic groups?; and ( iii ) How well does species richness perform as an indicator of CES value compared with revealed social preferences for wildflower communities? Public forest visitors ( n = 293) were surveyed during the summer of 2015 and asked to choose among images of wildflower communities in which flower species richness, flower abundance, species evenness, color diversity, and presence of charismatic species had been digitally manipulated. Aesthetic preferences among images were unrelated to species richness but increased with more abundant flowers, greater species evenness, and greater color diversity. Aesthetic preferences were consistent across psychographic groups and unaffected by knowledge of local flora or value placed on wildflower viewing. When actual wildflower communities ( n = 54) were ranked based on empirically measured flower species richness or wildflower viewing utility based on multinomial logit models of revealed preferences, rankings were broadly similar. However, designation of hotspots (CES values above the median) based on species richness alone missed 27% of wildflower viewing utility hotspots. Thus, conservation priorities for sustaining CES should incorporate social preferences and consider multiple dimensions of biodiversity that underpin CES supply.

Changing health behaviors to improve health outcomes after angioplasty: a randomized trial of net present value versus future value risk communication.

PubMed

Charlson, M E; Peterson, J C; Boutin-Foster, C; Briggs, W M; Ogedegbe, G G; McCulloch, C E; Hollenberg, J; Wong, C; Allegrante, J P

2008-10-01

Patients who have undergone angioplasty experience difficulty modifying at-risk behaviors for subsequent cardiac events. The purpose of this study was to test whether an innovative approach to framing of risk, based on 'net present value' economic theory, would be more effective in behavioral intervention than the standard 'future value approach' in reducing cardiovascular morbidity and mortality following angioplasty. At baseline, all patients completed a health assessment, received an individualized risk profile and selected risk factors for modification. The intervention randomized patients into two varying methods for illustrating positive effects of behavior change. For the experimental group, each selected risk factor was assigned a numeric biologic age (the net present value) that approximated the relative potential to improve current health status and quality of life when modifying that risk factor. In the control group, risk reduction was framed as the value of preventing future health problems. Ninety-four percent of patients completed 2-year follow-up. There was no difference between the rates of death, stroke, myocardial infarction, Class II-IV angina or severe ischemia (on non-invasive testing) between the net present value group and the future value group. Our results show that a net present risk communication intervention did not result in significant differences in health outcomes.

Rescaling quality of life values from discrete choice experiments for use as QALYs: a cautionary tale

PubMed Central

Flynn, Terry N; Louviere, Jordan J; Marley, Anthony AJ; Coast, Joanna; Peters, Tim J

2008-01-01

Background Researchers are increasingly investigating the potential for ordinal tasks such as ranking and discrete choice experiments to estimate QALY health state values. However, the assumptions of random utility theory, which underpin the statistical models used to provide these estimates, have received insufficient attention. In particular, the assumptions made about the decisions between living states and the death state are not satisfied, at least for some people. Estimated values are likely to be incorrectly anchored with respect to death (zero) in such circumstances. Methods Data from the Investigating Choice Experiments for the preferences of older people CAPability instrument (ICECAP) valuation exercise were analysed. The values (previously anchored to the worst possible state) were rescaled using an ordinal model proposed previously to estimate QALY-like values. Bootstrapping was conducted to vary artificially the proportion of people who conformed to the conventional random utility model underpinning the analyses. Results Only 26% of respondents conformed unequivocally to the assumptions of conventional random utility theory. At least 14% of respondents unequivocally violated the assumptions. Varying the relative proportions of conforming respondents in sensitivity analyses led to large changes in the estimated QALY values, particularly for lower-valued states. As a result these values could be either positive (considered to be better than death) or negative (considered to be worse than death). Conclusion Use of a statistical model such as conditional (multinomial) regression to anchor quality of life values from ordinal data to death is inappropriate in the presence of respondents who do not conform to the assumptions of conventional random utility theory. This is clearest when estimating values for that group of respondents observed in valuation samples who refuse to consider any living state to be worse than death: in such circumstances the model

Personal and professional values held by baccalaureate nursing students.

PubMed

Kaya, Hülya; Işik, Burçin; Şenyuva, Emine; Kaya, Nurten

2017-09-01

Values are ideals and beliefs that individuals and groups uphold and lie at the core of the diverse world of human behaviour and are expressed in every human decision and action, both consciously and unconsciously. They represent basic beliefs of what is right, good or desirable and motivate both personal and professional behaviour. In the context of nursing profession, values are essential in order to maintain high standards of the nursing care. This study was planned to examine changes in nursing students' personal and professional values between entering and graduating from an undergraduate nursing programme. Ethical considerations: Measures to protect participants included obtaining Deaconship of Nursing Faculty approval, obtaining signed informed consent and maintaining confidentiality. This study was designed as longitudinal quality. The research population included 143 students registered at a first grade of a nursing faculty for the 2009-2010 academic year. Data were collected with a Questionnaire Form, the Value Preferences Scale, the Professional Values Precedence Scale and the Nursing Professional Values Scale. According to the results, social values have statistical differences in 4-year nursing education. Nursing students in second class have higher score in terms of social values than those in third class. Also, majority of students ranked human dignity as first and justice as second and third from first to fourth classes, and they have very high scores on Nursing Professional Values Scale and its subscales and stated that all items of Nursing Professional Values Scale are very important. As a result, nursing education has vital role in acquiring and maintaining professional values.

The Slowly Varying Corona. I. Daily Differential Emission Measure Distributions Derived from EVE Spectra

NASA Astrophysics Data System (ADS)

Schonfeld, S. J.; White, S. M.; Hock-Mysliwiec, R. A.; McAteer, R. T. J.

2017-08-01

Daily differential emission measure (DEM) distributions of the solar corona are derived from spectra obtained by the Extreme-ultraviolet Variability Experiment (EVE) over a 4 yr period starting in 2010 near solar minimum and continuing through the maximum of solar cycle 24. The DEMs are calculated using six strong emission features dominated by Fe lines of charge states viii, ix, xi, xii, xiv, and xvi that sample the nonflaring coronal temperature range 0.3-5 MK. A proxy for the non-Fe xviii emission in the wavelength band around the 93.9 Å line is demonstrated. There is little variability in the cool component of the corona (T < 1.3 MK) over the 4 yr, suggesting that the quiet-Sun corona does not respond strongly to the solar cycle, whereas the hotter component (T > 2.0 MK) varies by more than an order of magnitude. A discontinuity in the behavior of coronal diagnostics in 2011 February-March, around the time of the first X-class flare of cycle 24, suggests fundamentally different behavior in the corona under solar minimum and maximum conditions. This global state transition occurs over a period of several months. The DEMs are used to estimate the thermal energy of the visible solar corona (of order 1031 erg), its radiative energy loss rate ((2.5-8) × {10}27 erg s-1), and the corresponding energy turnover timescale (about an hour). The uncertainties associated with the DEMs and these derived values are mostly due to the coronal Fe abundance and density and the CHIANTI atomic line database.

Stabilization of kerosene/water emulsions using bioemulsifiers obtained by fermentation of hemicellulosic sugars with Lactobacillus pentosus.

PubMed

Portilla-Rivera, Oscar Manuel; Torrado, Ana María; Domínguez, José Manuel; Moldes, Ana Belén

2010-09-22

The results of the present study show that Lactobacillus pentosus can produce extracellular bioemulsifiers by utilizing hemicellulosic sugars from grape marc as a source of carbon. The effectiveness of these bioemulsifiers (LPEM) was studied by preparing kerosene/water (K/W) emulsions in the presence and absence of these emulsifiers. Various parameters such as relative emulsion volume (EV), stabilizing capacity (ES), viscosity, and droplet size of K/W emulsions were measured. The EV values for K/W emulsions stabilized by concentrated LPEM were approximately 74.5% after 72 h of emulsion formation, with ES values of 97%. These values were higher than those obtained with dodecyl sodium sulfate as emulsifier (EV=62.3% and ES=87.7%). Additionally, K/W emulsions stabilized by LPEM produced polydisperse emulsions containing droplets of radius between 10 and 40 μm, which were smaller than those obtained for K/W emulsions without LPEM (droplet radius=60-100 μm). Moreover, the viscosity values of the K/W emulsions without and with LPEM were approximately 236 and 495 cP, respectively.

Relation of Different Type Love-Shida Numbers Determined with the Use of Time-Varying Incremental Gravitational Potential

NASA Astrophysics Data System (ADS)

Varga, Peter; Grafarend, Erik; Engels, Johannes

2017-03-01

There are different equations to describe relations between different classes of Love-Shida numbers. In this study with the use of the time-varying gravitational potential an integral relation was obtained which connects tidal Love-Shida numbers (h, l, k), load numbers (h', l', k'), potential free Love-Shida numbers generated by normal (h″, l″, k″) and horizontal (h‴, l‴, k‴) stresses. The equations obtained in frame of present study is the only one which - holds for every type of Love-Shida numbers, - describes a relationship not between different, but the same type of Love-Shida numbers, - does not follow from the sixth-order differential equation system of motion usually applied to calculate the Love-Shida numbers.

Analysis of loss of time value during road maintenance project

NASA Astrophysics Data System (ADS)

Sudarsana, Dewa Ketut; Sanjaya, Putu Ari

2017-06-01

Lane closure is frequently performed in the execution of the road maintenance project. It has a negative impact on road users such as the loss of vehicle operating costs and the loss of time value. Nevertheless, analysis on loss of time value in Indonesia has not been carried out. The parameter of time value for the road users was the minimum wage city/region approach. Vehicle speed of pre-construction was obtained by observation, while the speed during the road maintenance project was predicted by the speed of the pre-construction by multiplying it with the speed adjustment factor. In the case of execution of the National road maintenance project in the two-lane two-way urban and interurban road types in the fiscal year of 2015 in Bali province, the loss of time value was at the average of IDR 12,789,000/day/link road. The relationship of traffic volume and loss of time value of the road users was obtained by a logarithm model.

Economic Value of Instream Flow for Non-Commercial Whitewater Boating Using Recreation Demand and Contingent Valuation Methods

NASA Astrophysics Data System (ADS)

Loomis, John; McTernan, James

2014-03-01

Whitewater river kayaking and river rafting require adequate instream flows that are often adversely affected by upstream water diversions. However, there are very few studies in the USA of the economic value of instream flow to inform environmental managers. This study estimates the economic value of instream flow to non-commercial kayakers derived using a Travel Cost Method recreation demand model and Contingent Valuation Method (CVM), a type of Contingent Behavior Method (CBM). Data were obtained from a visitor survey administered along the Poudre River in Colorado. In the dichotomous choice CVM willingness to pay (WTP) question, visitors were asked if they would still visit the river if the cost of their trip was Y higher, and the level of Y was varied across the sample. The CVM yielded an estimate of WTP that was sensitive to flows ranging from 55 per person per day at 300 Cubic Feet per Second (CFS) to a maximum 97 per person per day at flows of 1900 CFS. The recreation demand model estimated a boater's number of trips per season. We found the number of trips taken was also sensitive to flow, ranging from as little as 1.63 trips at 300 CFS to a maximum number of 14 trips over the season at 1900 CFS. Thus, there is consistency between peak benefits per trip and number of trips, respectively. With an average of about 100 non-commercial boaters per day, the maximum marginal values per acre foot averages about 220. This value exceeds irrigation water values in this area of Colorado.

Continuous higher-order sliding mode control with time-varying gain for a class of uncertain nonlinear systems.

PubMed

Han, Yaozhen; Liu, Xiangjie

2016-05-01

This paper presents a continuous higher-order sliding mode (HOSM) control scheme with time-varying gain for a class of uncertain nonlinear systems. The proposed controller is derived from the concept of geometric homogeneity and super-twisting algorithm, and includes two parts, the first part of which achieves smooth finite time stabilization of pure integrator chains. The second part conquers the twice differentiable uncertainty and realizes system robustness by employing super-twisting algorithm. Particularly, time-varying switching control gain is constructed to reduce the switching control action magnitude to the minimum possible value while keeping the property of finite time convergence. Examples concerning the perturbed triple integrator chains and excitation control for single-machine infinite bus power system are simulated respectively to demonstrate the effectiveness and applicability of the proposed approach. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Added value of double reading in diagnostic radiology,a systematic review.

PubMed

Geijer, Håkan; Geijer, Mats

2018-06-01

Double reading in diagnostic radiology can find discrepancies in the original report, but a systematic program of double reading is resource consuming. There are conflicting opinions on the value of double reading. The purpose of the current study was to perform a systematic review on the value of double reading. A systematic review was performed to find studies calculating the rate of misses and overcalls with the aim of establishing the added value of double reading by human observers. The literature search resulted in 1610 hits. After abstract and full-text reading, 46 articles were selected for analysis. The rate of discrepancy varied from 0.4 to 22% depending on study setting. Double reading by a sub-specialist, in general, led to high rates of changed reports. The systematic review found rather low discrepancy rates. The benefit of double reading must be balanced by the considerable number of working hours a systematic double-reading scheme requires. A more profitable scheme might be to use systematic double reading for selected, high-risk examination types. A second conclusion is that there seems to be a value of sub-specialisation for increased report quality. A consequent implementation of this would have far-reaching organisational effects. • In double reading, two or more radiologists read the same images. • A systematic literature review was performed. • The discrepancy rates varied from 0.4 to 22% in various studies. • Double reading by sub-specialists found high discrepancy rates.

Do petroleum-based protective coatings add fuel value to slash

Treesearch

James L. Murphy; Charles W. Philpot

1965-01-01

Asphalts and wax emulsions have been recommended as protective coatings to help obtain clean, safe burns in slash disposal work. Fuel value determinations in the laboratory indicate that such coatings add little to the fuel value of slash.

Valuing Trial Designs from a Pharmaceutical Perspective Using Value-Based Pricing.

PubMed

Breeze, Penny; Brennan, Alan

2015-11-01

Our aim was to adapt the traditional framework for expected net benefit of sampling (ENBS) to be more compatible with drug development trials from the pharmaceutical perspective. We modify the traditional framework for conducting ENBS and assume that the price of the drug is conditional on the trial outcomes. We use a value-based pricing (VBP) criterion to determine price conditional on trial data using Bayesian updating of cost-effectiveness (CE) model parameters. We assume that there is a threshold price below which the company would not market the new intervention. We present a case study in which a phase III trial sample size and trial duration are varied. For each trial design, we sampled 10,000 trial outcomes and estimated VBP using a CE model. The expected commercial net benefit is calculated as the expected profits minus the trial costs. A clinical trial with shorter follow-up, and larger sample size, generated the greatest expected commercial net benefit. Increasing the duration of follow-up had a modest impact on profit forecasts. Expected net benefit of sampling can be adapted to value clinical trials in the pharmaceutical industry to optimise the expected commercial net benefit. However, the analyses can be very time consuming for complex CE models. © 2014 The Authors. Health Economics published by John Wiley & Sons Ltd.

Evaluation of Varying Biochars as Carrier Materials for Bacterial Soil Inoculants

NASA Astrophysics Data System (ADS)

Hale, Lauren; Crowley, David

2014-05-01

The incorporation of biochar into agricultural soils for carbon sequestration and improved soil fertility creates an opportunity to simultaneously deliver plant-growth promoting rhizobacteria (PGPR). Many characteristics of biochar materials indicate that these particles could be conducive as inoculum carriers. This could provide a value-added component for biochar marketing and has an advantage over traditional carrier materials, which can be unsustainable or expensive to produce. Here, we assessed the suitability of 10 biochar types, made from 5 feedstocks at 2 pyrolysis temperatures (300°C and 600°C), to serve as carriers for 2 model PGPR strains, Enterobacter cloacae UW5 and Pseudomonas putida UW4. All biochars were characterized based on BET specific surface area, C-N content, pH, EC, and their abilities to adsorb bacterial cells from a liquid inoculum. Further studies incorporated qPCR to quantify the survival of inoculants after introduction into soils via biochar carriers. The biochars that performed well were further assayed for their influence on PGPR traits, 1-aminocyclopropane-1-carboxylate (ACC) deaminase and auxin production. Peat and vermiculite served as traditional carrier materials to which we compared the biochars. Our findings indicated that biochars varied in their interactions with our model PGPR strains. Based on our analysis several biochar types were able to serve as carriers which were as good, if not better than, the traditional carrier materials. Future work should seek to assess shelf life and varying inoculation methods for the biochar-inoculant complexes.

Definitions of climate and climate change under varying external conditions

NASA Astrophysics Data System (ADS)

Werndl, C.

2014-06-01

Commonly, definitions of climate are endorsed where the external conditions are held constant. This paper argues that these definitions risk being empirically void because in reality the external conditions vary. As a consequence, analogous definitions for varying external conditions are explored with help of the recently developed theory of non-autonomous dynamical systems, and the similarities and differences between the cases of constant and varying external conditions are discussed. It is argued that there are analogous definitions for varying external conditions which are preferable to the definitions where the external conditions are held constant. In this context, a novel definition is proposed (namely, climate as the distribution over time under a regime of varying external conditions), which is argued to be promising.

Approximation-based adaptive tracking control of pure-feedback nonlinear systems with multiple unknown time-varying delays.

PubMed

Wang, Min; Ge, Shuzhi Sam; Hong, Keum-Shik

2010-11-01

This paper presents adaptive neural tracking control for a class of non-affine pure-feedback systems with multiple unknown state time-varying delays. To overcome the design difficulty from non-affine structure of pure-feedback system, mean value theorem is exploited to deduce affine appearance of state variables x(i) as virtual controls α(i), and of the actual control u. The separation technique is introduced to decompose unknown functions of all time-varying delayed states into a series of continuous functions of each delayed state. The novel Lyapunov-Krasovskii functionals are employed to compensate for the unknown functions of current delayed state, which is effectively free from any restriction on unknown time-delay functions and overcomes the circular construction of controller caused by the neural approximation of a function of u and [Formula: see text] . Novel continuous functions are introduced to overcome the design difficulty deduced from the use of one adaptive parameter. To achieve uniformly ultimate boundedness of all the signals in the closed-loop system and tracking performance, control gains are effectively modified as a dynamic form with a class of even function, which makes stability analysis be carried out at the present of multiple time-varying delays. Simulation studies are provided to demonstrate the effectiveness of the proposed scheme.

Dealing with the health state 'dead' when using discrete choice experiments to obtain values for EQ-5D-5L heath states.

PubMed

Ramos-Goñi, Juan Manuel; Rivero-Arias, Oliver; Errea, María; Stolk, Elly A; Herdman, Michael; Cabasés, Juan Manuel

2013-07-01

To evaluate two different methods to obtain a dead (0)--full health (1) scale for EQ-5D-5L valuation studies when using discrete choice (DC) modeling. The study was carried out among 400 respondents from Barcelona who were representative of the Spanish population in terms of age, sex, and level of education. The DC design included 50 pairs of health states in five blocks. Participants were forced to choose between two EQ-5D-5L states (A and B). Two extra questions concerned whether A and B were considered worse than dead. Each participant performed ten choice exercises. In addition, values were collected using lead-time trade-off (lead-time TTO), for which 100 states in ten blocks were selected. Each participant performed five lead-time TTO exercises. These consisted of DC models offering the health state 'dead' as one of the choices--for which all participants' responses were used (DCdead)--and a model that included only the responses of participants who chose at least one state as worse than dead (WTD) (DCWTD). The study also estimated DC models rescaled with lead-time TTO data and a lead-time TTO linear model. The DC(dead) and DCWTD models produced relatively similar results, although the coefficients in the DCdead model were slightly lower. The DC model rescaled with lead-time TTO data produced higher utility decrements. Lead-time TTO produced the highest utility decrements. The incorporation of the state 'dead' in the DC models produces results in concordance with DC models that do not include 'dead'.

Gut microbiomes of Indian children of varying nutritional status.

PubMed

Ghosh, Tarini Shankar; Gupta, Sourav Sen; Bhattacharya, Tanudeep; Yadav, Deepak; Barik, Anamitra; Chowdhury, Abhijit; Das, Bhabatosh; Mande, Sharmila S; Nair, G Balakrish

2014-01-01

Malnutrition is a global health problem affecting more than 300 million pre-school children worldwide. It is one of the major health concerns in India since around 50% of children below the age of two suffer from various forms of malnutrition. The gut microbiome plays an important role in nutrient pre-processing, assimilation and energy harvest from food. Consequently, dysbiosis of the gut microbiota has been implicated in malnutrition. Metagenomics approach was adopted to investigate the gut microbiome sampled from 20 rural Indian children with varying nutritional status. The changes in the abundances of various taxonomic and functional groups were investigated across these gut microbiomes. A core set of 23 genera were observed across samples, with some showing differential abundances with varying nutritional status. One of the findings of the current study is the positive/negative associations of specific taxonomic and functional groups with the nutritional status of the children. Notable alterations in the architecture of the inter-microbial co-occurrence networks were also observed with changes in nutritional status. A key example is the clustering of potentially pathogenic groups into a distinct hub in severely malnourished gut. Our data does not demonstrate causality with the microbiome patterns that we observed, rather a description of some interesting patterns, whose underlying mechanism remains to be uncovered. The present study envisioned interrelationships between the pattern of gut microbiome and the nutritional status of children. The cause of this pattern needs to be explored. However, insights obtained from the present study form the basis for further metagenomic investigations on larger population of children. Results of such studies will be useful in identifying the key microbial groups that can be utilized for targeted therapeutic interventions for managing severe acute malnutrition.

Hydrodynamic simulations of accretion flows with time-varying viscosity

NASA Astrophysics Data System (ADS)

Roy, Abhishek; Chakrabarti, Sandip K.

2017-12-01

X-ray outbursts of stellar-mass black hole candidates are believed to be due to a sudden rise in viscosity, which transports angular momentum efficiently and increases the accretion rates, causing higher X-ray flux. After the viscosity is reduced, the outburst subsides and the object returns back to the pre-outburst quiescence stage. In the absence of a satisfactory understanding of the physical mechanism leading to such a sharp time dependence of viscous processes, we perform numerical simulations where we include the rise and fall of a viscosity parameter at an outer injection grid, assumed to be located at the accumulation radius where matter from the companion is piled up before being released by enhanced viscosity. We use a power-law radial dependence of the viscosity parameter (α ∼ rε), but the exponent (ε) is allowed to vary with time to mimic a fast rise and decay of the viscosity parameter. Since X-ray spectra of a black hole candidate can be explained by a Keplerian disc component in the presence of a post-shock region of an advective flow, our goal here is also to understand whether the flow configurations required to explain the spectral states of an outbursting source could be obtained by a time-varying viscosity. We present the results of our simulations to prove that low-angular-momentum (sub-Keplerian) advective flows do form a Keplerian disc in the pre-shock region when the viscosity is enhanced, which disappears on a much longer time-scale after the viscosity is withdrawn. From the variation of the Keplerian disc inside an advective halo, we believe that our result, for the first time, is able to simulate the two-component advective flow dynamics during an entire X-ray outburst and explain the observed hysteresis effects in the hardness-intensity diagram.

Gut Microbiomes of Indian Children of Varying Nutritional Status

PubMed Central

Bhattacharya, Tanudeep; Yadav, Deepak; Barik, Anamitra; Chowdhury, Abhijit; Das, Bhabatosh; Mande, Sharmila S.; Nair, G. Balakrish

2014-01-01

Background Malnutrition is a global health problem affecting more than 300 million pre-school children worldwide. It is one of the major health concerns in India since around 50% of children below the age of two suffer from various forms of malnutrition. The gut microbiome plays an important role in nutrient pre-processing, assimilation and energy harvest from food. Consequently, dysbiosis of the gut microbiota has been implicated in malnutrition. Methodology/Principal Findings Metagenomics approach was adopted to investigate the gut microbiome sampled from 20 rural Indian children with varying nutritional status. The changes in the abundances of various taxonomic and functional groups were investigated across these gut microbiomes. A core set of 23 genera were observed across samples, with some showing differential abundances with varying nutritional status. One of the findings of the current study is the positive/negative associations of specific taxonomic and functional groups with the nutritional status of the children. Notable alterations in the architecture of the inter-microbial co-occurrence networks were also observed with changes in nutritional status. A key example is the clustering of potentially pathogenic groups into a distinct hub in severely malnourished gut. Our data does not demonstrate causality with the microbiome patterns that we observed, rather a description of some interesting patterns, whose underlying mechanism remains to be uncovered. Conclusions The present study envisioned interrelationships between the pattern of gut microbiome and the nutritional status of children. The cause of this pattern needs to be explored. However, insights obtained from the present study form the basis for further metagenomic investigations on larger population of children. Results of such studies will be useful in identifying the key microbial groups that can be utilized for targeted therapeutic interventions for managing severe acute malnutrition. PMID

The perception of emotion and focus prosody with varying acoustic cues in cochlear implant simulations with varying filter slopes

PubMed Central

van de Velde, Daan J.; Schiller, Niels O.; van Heuven, Vincent J.; Levelt, Claartje C.; van Ginkel, Joost; Beers, Mieke; Briaire, Jeroen J.; Frijns, Johan H. M.

2017-01-01

This study aimed to find the optimal filter slope for cochlear implant simulations (vocoding) by testing the effect of a wide range of slopes on the discrimination of emotional and linguistic (focus) prosody, with varying availability of F0 and duration cues. Forty normally hearing participants judged if (non-)vocoded sentences were pronounced with happy or sad emotion, or with adjectival or nominal focus. Sentences were recorded as natural stimuli and manipulated to contain only emotion- or focus-relevant segmental duration or F0 information or both, and then noise-vocoded with 5, 20, 80, 120, and 160 dB/octave filter slopes. Performance increased with steeper slopes, but only up to 120 dB/octave, with bigger effects for emotion than for focus perception. For emotion, results with both cues most closely resembled results with F0, while for focus results with both cues most closely resembled those with duration, showing emotion perception relies primarily on F0, and focus perception on duration. This suggests that filter slopes affect focus perception less than emotion perception because for emotion, F0 is both more informative and more affected. The performance increase until extreme filter slope values suggests that much performance improvement in prosody perception is still to be gained for CI users. PMID:28599540

Children's perceived cost for exercise: application of an expectancy-value paradigm.

PubMed

Chiang, Evelyn S; Byrd, Sandra P; Molin, Ashley J

2011-04-01

Expectancy-value models of motivation have been applied to understanding children's choices in areas such as academics and sports. Here, an expectancy-value paradigm is applied to exercising (defined as engaging in physical activity). The notion of perceived cost is highlighted in particular. Two hundred twenty children in third, fourth, and fifth grades were surveyed on their competence beliefs, perceived importance, interest, and perceived cost of being physically active. Results indicated that perceived cost is empirically distinct from competence beliefs and other types of value, that perceived cost is marginally related to children's self-reported level of physical activity, and children's beliefs and other values are related to their self-reported level of physical activity. Children's perceptions of cost vary depending on grade and gender. Interventions based on these findings are proposed.

Human perceptions of colour rendition vary with average fidelity, average gamut, and gamut shape

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

Royer, MP; Wilkerson, A.; Wei, M.

An experiment was conducted to evaluate how subjective impressions of color quality vary with changes in average fidelity, average gamut, and gamut shape (which considers the specific hues that are saturated or desaturated). Twenty-eight participants each evaluated 26 lighting conditions—created using four, seven-channel, tunable LED luminaires—in a 3.1 m by 3.7 m room filled with objects selected to cover a range of hue, saturation, and lightness. IES TM-30 fidelity index (Rf) values ranged from 64 to 93, IES TM-30 gamut index (Rg¬) values from 79 to 117, and IES TM-30 Rcs,h1 values (a proxy for gamut shape) from -19% tomore » 26%. All lighting conditions delivered the same nominal illuminance and chromaticity. Participants were asked to rate each condition on eight point semantic differential scales for saturated-dull, normal-shifted, and like-dislike. They were also asked one multiple choice question, classifying the condition as saturated, dull, normal, or shifted. The findings suggest that gamut shape is more important than average gamut for human preference, where reds play a more important role than other hues. Additionally, average fidelity alone is a poor predictor of human perceptions, although Rf was somewhat better than CIE Ra. The most preferred source had a CIE Ra value of 68, and 9 of the top 12 rated products had a CIE Ra value of 73 or less, which indicates that the commonly used criteria of CIE Ra ≥ 80 may be excluding a majority of preferred light sources.« less

Specimen loading list for the varying temperature experiment

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

Qualls, A.L.; Sitterson, R.G.

1998-09-01

The varying temperature experiment HFIR-RB-13J has been assembled and inserted in the reactor. Approximately 5300 specimens were cleaned, inspected, matched, and loaded into four specimen holders. A listing of each specimen loaded into the steady temperature holder, its position in the capsule, and the identification of the corresponding specimen loaded into the varying temperature holder is presented in this report.

Discrimination Method of the Volatiles from Fresh Mushrooms by an Electronic Nose Using a Trapping System and Statistical Standardization to Reduce Sensor Value Variation

PubMed Central

Fujioka, Kouki; Shimizu, Nobuo; Manome, Yoshinobu; Ikeda, Keiichi; Yamamoto, Kenji; Tomizawa, Yasuko

2013-01-01

Electronic noses have the benefit of obtaining smell information in a simple and objective manner, therefore, many applications have been developed for broad analysis areas such as food, drinks, cosmetics, medicine, and agriculture. However, measurement values from electronic noses have a tendency to vary under humidity or alcohol exposure conditions, since several types of sensors in the devices are affected by such variables. Consequently, we show three techniques for reducing the variation of sensor values: (1) using a trapping system to reduce the infering components; (2) performing statistical standardization (calculation of z-score); and (3) selecting suitable sensors. With these techniques, we discriminated the volatiles of four types of fresh mushrooms: golden needle (Flammulina velutipes), white mushroom (Agaricus bisporus), shiitake (Lentinus edodes), and eryngii (Pleurotus eryngii) among six fresh mushrooms (hen of the woods (Grifola frondosa), shimeji (Hypsizygus marmoreus) plus the above mushrooms). Additionally, we succeeded in discrimination of white mushroom, only comparing with artificial mushroom flavors, such as champignon flavor and truffle flavor. In conclusion, our techniques will expand the options to reduce variations in sensor values. PMID:24233028

Lipid Extraction and the Fugacity of Stable Isotope Values

NASA Astrophysics Data System (ADS)

Padula, V.; Causey, D.; Wolf, N.; Welker, J. M.

2013-12-01

Stable isotope analysis of blood, feathers, and other tissues are often used to infer migration patterns, diet composition and trophic status of seabirds. Tissues contain variable amounts of lipids that are depleted in the heavy carbon isotope (13C) and may introduce a bias in these values. There is evidence that lipid extraction may affect other stable isotope ratios, such as δ15N. Consequently, correction factors need to be applied to appropriately interpret δ13C and δ15N values for individual species and tissue type. In this study, we collected seven species of seabirds from the Near Islands, the western most group of islands in the Aleutian Island archipelago. We sampled kidney, liver, heart and muscle samples from each bird and after freeze drying, individual tissue samples were divided into two subsamples. We left one subsample unaltered and extracted lipids from the other subsample using a 2:1 chloroform-methanol solution. We found that the change in δ13C values after lipid extraction (Δδ13C) varied widely among categories (eg., species, tissue type) from 0 - 4 ‰, while Δδ15N values ranged from 0 to 2‰. Notably, within category variation was nonsignificant and the Δδ values were linear against the covariant C:N ratio of the isotopic data, which allows us to use arithmetic corrections for categorical values. Our data strongly indicate that the effects of lipid extraction on stable isotopic values, while linear within category, vary widely by species, tissue, geographic area, year of collection, and isotope. Fugacity is usually employed as a thermodynamic quantity related to the chemical potential or activity that characterizes the escaping tendency from a phase (eg. Mackay & Paterson 1982). Here we use fugacity in the earlier, broader sense of fleeting, transitory, or instable states (eg., S. Johnson 1751), and its measure may be approximated by the higher order variance of Δδ13C and Δδ15N among data categories. Clearly, understanding the

Evaluation of marginal and internal gaps of metal ceramic crowns obtained from conventional impressions and casting techniques with those obtained from digital techniques.

PubMed

Rai, Rathika; Kumar, S Arun; Prabhu, R; Govindan, Ranjani Thillai; Tanveer, Faiz Mohamed

2017-01-01

Accuracy in fit of cast metal restoration has always remained as one of the primary factors in determining the success of the restoration. A well-fitting restoration needs to be accurate both along its margin and with regard to its internal surface. The aim of the study is to evaluate the marginal fit of metal ceramic crowns obtained by conventional inlay casting wax pattern using conventional impression with the metal ceramic crowns obtained by computer-aided design and computer-aided manufacturing (CAD/CAM) technique using direct and indirect optical scanning. This in vitro study on preformed custom-made stainless steel models with former assembly that resembles prepared tooth surfaces of standardized dimensions comprised three groups: the first group included ten samples of metal ceramic crowns fabricated with conventional technique, the second group included CAD/CAM-milled direct metal laser sintering (DMLS) crowns using indirect scanning, and the third group included DMLS crowns fabricated by direct scanning of the stainless steel model. The vertical marginal gap and the internal gap were evaluated with the stereomicroscope (Zoomstar 4); post hoc Turkey's test was used for statistical analysis. One-way analysis of variance method was used to compare the mean values. Metal ceramic crowns obtained from direct optical scanning showed the least marginal and internal gap when compared to the castings obtained from inlay casting wax and indirect optical scanning. Indirect and direct optical scanning had yielded results within clinically acceptable range.

Forecasting the value-at-risk of Chinese stock market using the HARQ model and extreme value theory

NASA Astrophysics Data System (ADS)

Liu, Guangqiang; Wei, Yu; Chen, Yongfei; Yu, Jiang; Hu, Yang

2018-06-01

Using intraday data of the CSI300 index, this paper discusses value-at-risk (VaR) forecasting of the Chinese stock market from the perspective of high-frequency volatility models. First, we measure the realized volatility (RV) with 5-minute high-frequency returns of the CSI300 index and then model it with the newly introduced heterogeneous autoregressive quarticity (HARQ) model, which can handle the time-varying coefficients of the HAR model. Second, we forecast the out-of-sample VaR of the CSI300 index by combining the HARQ model and extreme value theory (EVT). Finally, using several popular backtesting methods, we compare the VaR forecasting accuracy of HARQ model with other traditional HAR-type models, such as HAR, HAR-J, CHAR, and SHAR. The empirical results show that the novel HARQ model can beat other HAR-type models in forecasting the VaR of the Chinese stock market at various risk levels.

Electric fields induced in the human body by time-varying magnetic field gradients in MRI: numerical calculations and correlation analysis.

PubMed

Bencsik, Martin; Bowtell, Richard; Bowley, Roger

2007-05-07

The spatial distributions of the electric fields induced in the human body by switched magnetic field gradients in MRI have been calculated numerically using the commercial software package, MAFIA, and the three-dimensional, HUGO body model that comprises 31 different tissue types. The variation of |J|, |E| and |B| resulting from exposure of the body model to magnetic fields generated by typical whole-body x-, y- and z-gradient coils has been analysed for three different body positions (head-, heart- and hips-centred). The magnetic field varied at 1 kHz, so as to produce a rate of change of gradient of 100 T m(-1) s(-1) at the centre of each coil. A highly heterogeneous pattern of induced electric field and current density was found to result from the smoothly varying magnetic field in all cases, with the largest induced electric fields resulting from application of the y-gradient, in agreement with previous studies. By applying simple statistical analysis to electromagnetic quantities within axial planes of the body model, it is shown that the induced electric field is strongly correlated to the local value of resistivity, and the induced current density exhibits even stronger correlation with the local conductivity. The local values of the switched magnetic field are however shown to bear little relation to the local values of the induced electric field or current density.

Estimating Time-Varying PCB Exposures Using Person-Specific Predictions to Supplement Measured Values: A Comparison of Observed and Predicted Values in Two Cohorts of Norwegian Women.

PubMed

Nøst, Therese Haugdahl; Breivik, Knut; Wania, Frank; Rylander, Charlotta; Odland, Jon Øyvind; Sandanger, Torkjel Manning

2016-03-01

Studies on the health effects of polychlorinated biphenyls (PCBs) call for an understanding of past and present human exposure. Time-resolved mechanistic models may supplement information on concentrations in individuals obtained from measurements and/or statistical approaches if they can be shown to reproduce empirical data. Here, we evaluated the capability of one such mechanistic model to reproduce measured PCB concentrations in individual Norwegian women. We also assessed individual life-course concentrations. Concentrations of four PCB congeners in pregnant (n = 310, sampled in 2007-2009) and postmenopausal (n = 244, 2005) women were compared with person-specific predictions obtained using CoZMoMAN, an emission-based environmental fate and human food-chain bioaccumulation model. Person-specific predictions were also made using statistical regression models including dietary and lifestyle variables and concentrations. CoZMoMAN accurately reproduced medians and ranges of measured concentrations in the two study groups. Furthermore, rank correlations between measurements and predictions from both CoZMoMAN and regression analyses were strong (Spearman's r > 0.67). Precision in quartile assignments from predictions was strong overall as evaluated by weighted Cohen's kappa (> 0.6). Simulations indicated large inter-individual differences in concentrations experienced in the past. The mechanistic model reproduced all measurements of PCB concentrations within a factor of 10, and subject ranking and quartile assignments were overall largely consistent, although they were weak within each study group. Contamination histories for individuals predicted by CoZMoMAN revealed variation between study subjects, particularly in the timing of peak concentrations. Mechanistic models can provide individual PCB exposure metrics that could serve as valuable supplements to measurements.

Physician Service Attribution Methods for Examining Provision of Low-Value Care.

PubMed

Chang, Eva; Buist, Diana Sm; Handley, Matthew; Pardee, Roy; Gundersen, Gabrielle; Reid, Robert J

2016-01-01

There has been significant research on provider attribution for quality and cost. Low-value care is an area of heightened focus, with little of the focus being on measurement; a key methodological decision is how to attribute delivered services and procedures. We illustrate the difference in relative and absolute physician- and panel-attributed services and procedures using overuse in cervical cancer screening. A retrospective, cross-sectional study in an integrated health care system. We used 2013 physician-level data from Group Health Cooperative to calculate two utilization attributions: (1) panel attribution with the procedure assigned to the physician's predetermined panel, regardless of who performed the procedure; and (2) physician attribution with the procedure assigned to the performing physician. We calculated the percentage of low-value cervical cancer screening tests and ranked physicians within the clinic using the two utilization attribution methods. The percentage of low-value cervical cancer screening varied substantially between physician and panel attributions. Across the whole delivery system, median panel- and physician-attributed percentages were 15 percent and 10 percent, respectively. Among sampled clinics, panel-attributed percentages ranged between 10 percent and 17 percent, and physician-attributed percentages ranged between 9 percent and 13 percent. Within a clinic, median panel-attributed screening percentage was 17 percent (range 0 percent-27 percent) and physician-attributed percentage was 11 percent (range 0 percent-24 percent); physician rank varied by attribution method. The attribution method is an important methodological decision when developing low-value care measures since measures may ultimately have an impact on national benchmarking and quality scores. Cross-organizational dialogue and transparency in low-value care measurement will become increasingly important for all stakeholders.

Study on the Variation of Groundwater Level under Time-varying Recharge

NASA Astrophysics Data System (ADS)

Wu, Ming-Chang; Hsieh, Ping-Cheng

2017-04-01

The slopes of the suburbs come to important areas by focusing on the work of soil and water conservation in recent years. The water table inside the aquifer is affected by rainfall, geology and topography, which will result in the change of groundwater discharge and water level. Currently, the way to obtain water table information is to set up the observation wells; however, owing to that the cost of equipment and the wells excavated is too expensive, we develop a mathematical model instead, which might help us to simulate the groundwater level variation. In this study, we will discuss the groundwater level change in a sloping unconfined aquifer with impermeable bottom under time-varying rainfall events. Referring to Child (1971), we employ the Boussinesq equation as the governing equation, and apply the General Integral Transforms Method (GITM) to analyzing the groundwater level after linearizing the Boussinesq equation. After comparing the solution with Verhoest & Troch (2000) and Bansal & Das (2010), we get satisfactory results. To sum up, we have presented an alternative approach to solve the linearized Boussinesq equation for the response of groundwater level in a sloping unconfined aquifer. The present analytical results combine the effect of bottom slope and the time-varying recharge pattern on the water table fluctuations. Owing to the limitation and difficulty of measuring the groundwater level directly, we develop such a mathematical model that we can predict or simulate the variation of groundwater level affected by any rainfall events in advance.

A Conversion Formula for Comparing Pulse Oximeter Desaturation Rates Obtained with Different Averaging Times

PubMed Central

Vagedes, Jan; Bialkowski, Anja; Wiechers, Cornelia; Poets, Christian F.; Dietz, Klaus

2014-01-01

Objective The number of desaturations determined in recordings of pulse oximeter saturation (SpO2) primarily depends on the time over which values are averaged. As the averaging time in pulse oximeters is not standardized, it varies considerably between centers. To make SpO2 data comparable, it is thus desirable to have a formula that allows conversion between desaturation rates obtained using different averaging times for various desaturation levels and minimal durations. Methods Oxygen saturation was measured for 170 hours in 12 preterm infants with a mean number of 65 desaturations <90% per hour of arbitrary duration by using a pulse oximeter in a 2–4 s averaging mode. Using 7 different averaging times between 3 and 16 seconds, the raw red-to-infrared data were reprocessed to determine the number of desaturations (D). The whole procedure was carried out for 7 different minimal desaturation durations (≥1, ≥5, ≥10, ≥15, ≥20, ≥25, ≥30 s) below SpO2 threshold values of 80%, 85% or 90% to finally reach a conversion formula. The formula was validated by splitting the infants into two groups of six children each and using one group each as a training set and the other one as a test set. Results Based on the linear relationship found between the logarithm of the desaturation rate and the logarithm of the averaging time, the conversion formula is: D2 = D1 (T2/T1)c, where D2 is the desaturation rate for the desired averaging time T2, and D1 is the desaturation rate for the original averaging time T1, with the exponent c depending on the desaturation threshold and the minimal desaturation duration. The median error when applying this formula was 2.6%. Conclusion This formula enables the conversion of desaturation rates between different averaging times for various desaturation thresholds and minimal desaturation durations. PMID:24489887

A conversion formula for comparing pulse oximeter desaturation rates obtained with different averaging times.

PubMed

Vagedes, Jan; Bialkowski, Anja; Wiechers, Cornelia; Poets, Christian F; Dietz, Klaus

2014-01-01

The number of desaturations determined in recordings of pulse oximeter saturation (SpO2) primarily depends on the time over which values are averaged. As the averaging time in pulse oximeters is not standardized, it varies considerably between centers. To make SpO2 data comparable, it is thus desirable to have a formula that allows conversion between desaturation rates obtained using different averaging times for various desaturation levels and minimal durations. Oxygen saturation was measured for 170 hours in 12 preterm infants with a mean number of 65 desaturations <90% per hour of arbitrary duration by using a pulse oximeter in a 2-4 s averaging mode. Using 7 different averaging times between 3 and 16 seconds, the raw red-to-infrared data were reprocessed to determine the number of desaturations (D). The whole procedure was carried out for 7 different minimal desaturation durations (≥ 1, ≥ 5, ≥ 10, ≥ 15, ≥ 20, ≥ 25, ≥ 30 s) below SpO2 threshold values of 80%, 85% or 90% to finally reach a conversion formula. The formula was validated by splitting the infants into two groups of six children each and using one group each as a training set and the other one as a test set. Based on the linear relationship found between the logarithm of the desaturation rate and the logarithm of the averaging time, the conversion formula is: D2 = D1 (T2/T1)(c), where D2 is the desaturation rate for the desired averaging time T2, and D1 is the desaturation rate for the original averaging time T1, with the exponent c depending on the desaturation threshold and the minimal desaturation duration. The median error when applying this formula was 2.6%. This formula enables the conversion of desaturation rates between different averaging times for various desaturation thresholds and minimal desaturation durations.

Stimulus Value Signals in Ventromedial PFC Reflect the Integration of Attribute Value Signals Computed in Fusiform Gyrus and Posterior Superior Temporal Gyrus

PubMed Central

Lim, Seung-Lark; O'Doherty, John P.

2013-01-01

We often have to make choices among multiattribute stimuli (e.g., a food that differs on its taste and health). Behavioral data suggest that choices are made by computing the value of the different attributes and then integrating them into an overall stimulus value signal. However, it is not known whether this theory describes the way the brain computes the stimulus value signals, or how the underlying computations might be implemented. We investigated these questions using a human fMRI task in which individuals had to evaluate T-shirts that varied in their visual esthetic (e.g., color) and semantic (e.g., meaning of logo printed in T-shirt) components. We found that activity in the fusiform gyrus, an area associated with the processing of visual features, correlated with the value of the visual esthetic attributes, but not with the value of the semantic attributes. In contrast, activity in posterior superior temporal gyrus, an area associated with the processing of semantic meaning, exhibited the opposite pattern. Furthermore, both areas exhibited functional connectivity with an area of ventromedial prefrontal cortex that reflects the computation of overall stimulus values at the time of decision. The results provide supporting evidence for the hypothesis that some attribute values are computed in cortical areas specialized in the processing of such features, and that those attribute-specific values are then passed to the vmPFC to be integrated into an overall stimulus value signal to guide the decision. PMID:23678116

Stimulus value signals in ventromedial PFC reflect the integration of attribute value signals computed in fusiform gyrus and posterior superior temporal gyrus.

PubMed

Lim, Seung-Lark; O'Doherty, John P; Rangel, Antonio

2013-05-15

We often have to make choices among multiattribute stimuli (e.g., a food that differs on its taste and health). Behavioral data suggest that choices are made by computing the value of the different attributes and then integrating them into an overall stimulus value signal. However, it is not known whether this theory describes the way the brain computes the stimulus value signals, or how the underlying computations might be implemented. We investigated these questions using a human fMRI task in which individuals had to evaluate T-shirts that varied in their visual esthetic (e.g., color) and semantic (e.g., meaning of logo printed in T-shirt) components. We found that activity in the fusiform gyrus, an area associated with the processing of visual features, correlated with the value of the visual esthetic attributes, but not with the value of the semantic attributes. In contrast, activity in posterior superior temporal gyrus, an area associated with the processing of semantic meaning, exhibited the opposite pattern. Furthermore, both areas exhibited functional connectivity with an area of ventromedial prefrontal cortex that reflects the computation of overall stimulus values at the time of decision. The results provide supporting evidence for the hypothesis that some attribute values are computed in cortical areas specialized in the processing of such features, and that those attribute-specific values are then passed to the vmPFC to be integrated into an overall stimulus value signal to guide the decision.

Analysis of Calorific Value of Tibarau Cane Briquette

NASA Astrophysics Data System (ADS)

Nurdin, H.; Hasanuddin, H.; Darmawi, D.; Prasetya, F.

2018-04-01

The development of product diversification through tibarau cane briquettes as an effort in obtaining alternative fuels. Tibarau cane is one of the potential materials of renewable energy sources that can be processed into briquette. So as to reduce dependence on energy fuel oil, which for the middle to lower class is the main requirement. Efforts and innovations tibarau cane briquettes in producing fuel that has quality and performance can be measured with calorific value. Prior to development of this potential required the existence of test and evaluation stages according to the order of the flow of new material product development. Through process technology of briquette product making with compaction and optimization of composition content on tapioca adhesive and mesh particles suitable to get optimum calorific value. The results obtained in this research are the development of tibarau cane briquette model which is recommended as replacement fuel. Where the calorific value of tibarau cane briquette is 11.221,72 kJ / kg at composition percentage 80: 20 and its density is 0,565 gr/cm3. The comparison of mass tibarau with tapioca, particle size, pressure force (compaction), can affect the calorific value and density of tibarau cane briquette.

A nonconformist account of the Asch experiments: values, pragmatics, and moral dilemmas.

PubMed

Hodges, Bert H; Geyer, Anne L

2006-01-01

This article offers a new approach to Asch's (1956) influential studies relating physical and social perception. Drawing on research on values, conversational pragmatics, cross-cultural comparisons, and negotiation, the authors challenge the normative assumptions that have led psychologists to interpret the studies in terms of conformity. A values-pragmatics account is offered that suggests that participants attempt to realize multiple values (e.g., truth, social solidarity) in an inherently frustrating situation by tacitly varying patterns of dissent and agreement to communicate larger scale truths and cooperative intentions. Alternative theories (e.g., embarrassment, attribution) are compared and empirical implications of the values-pragmatics account are evaluated. The possibility of multiple strategies promoting group survival and the proper role of moral evaluation in social psychological research are considered.

Discrete simulations of spatio-temporal dynamics of small water bodies under varied stream flow discharges

NASA Astrophysics Data System (ADS)

Daya Sagar, B. S.

2005-01-01

Spatio-temporal patterns of small water bodies (SWBs) under the influence of temporally varied stream flow discharge are simulated in discrete space by employing geomorphologically realistic expansion and contraction transformations. Cascades of expansion-contraction are systematically performed by synchronizing them with stream flow discharge simulated via the logistic map. Templates with definite characteristic information are defined from stream flow discharge pattern as the basis to model the spatio-temporal organization of randomly situated surface water bodies of various sizes and shapes. These spatio-temporal patterns under varied parameters (λs) controlling stream flow discharge patterns are characterized by estimating their fractal dimensions. At various λs, nonlinear control parameters, we show the union of boundaries of water bodies that traverse the water body and non-water body spaces as geomorphic attractors. The computed fractal dimensions of these attractors are 1.58, 1.53, 1.78, 1.76, 1.84, and 1.90, respectively, at λs of 1, 2, 3, 3.46, 3.57, and 3.99. These values are in line with general visual observations.

Estimation of Bid Curves in Power Exchanges using Time-varying Simultaneous-Equations Models

NASA Astrophysics Data System (ADS)

Ofuji, Kenta; Yamaguchi, Nobuyuki

Simultaneous-equations model (SEM) is generally used in economics to estimate interdependent endogenous variables such as price and quantity in a competitive, equilibrium market. In this paper, we have attempted to apply SEM to JEPX (Japan Electric Power eXchange) spot market, a single-price auction market, using the publicly available data of selling and buying bid volumes, system price and traded quantity. The aim of this analysis is to understand the magnitude of influences to the auctioned prices and quantity from the selling and buying bids, than to forecast prices and quantity for risk management purposes. In comparison with the Ordinary Least Squares (OLS) estimation where the estimation results represent average values that are independent of time, we employ a time-varying simultaneous-equations model (TV-SEM) to capture structural changes inherent in those influences, using State Space models with Kalman filter stepwise estimation. The results showed that the buying bid volumes has that highest magnitude of influences among the factors considered, exhibiting time-dependent changes, ranging as broad as about 240% of its average. The slope of the supply curve also varies across time, implying the elastic property of the supply commodity, while the demand curve remains comparatively inelastic and stable over time.

ESTIMATION OF CONSTANT AND TIME-VARYING DYNAMIC PARAMETERS OF HIV INFECTION IN A NONLINEAR DIFFERENTIAL EQUATION MODEL.

PubMed

Liang, Hua; Miao, Hongyu; Wu, Hulin

2010-03-01

Modeling viral dynamics in HIV/AIDS studies has resulted in deep understanding of pathogenesis of HIV infection from which novel antiviral treatment guidance and strategies have been derived. Viral dynamics models based on nonlinear differential equations have been proposed and well developed over the past few decades. However, it is quite challenging to use experimental or clinical data to estimate the unknown parameters (both constant and time-varying parameters) in complex nonlinear differential equation models. Therefore, investigators usually fix some parameter values, from the literature or by experience, to obtain only parameter estimates of interest from clinical or experimental data. However, when such prior information is not available, it is desirable to determine all the parameter estimates from data. In this paper, we intend to combine the newly developed approaches, a multi-stage smoothing-based (MSSB) method and the spline-enhanced nonlinear least squares (SNLS) approach, to estimate all HIV viral dynamic parameters in a nonlinear differential equation model. In particular, to the best of our knowledge, this is the first attempt to propose a comparatively thorough procedure, accounting for both efficiency and accuracy, to rigorously estimate all key kinetic parameters in a nonlinear differential equation model of HIV dynamics from clinical data. These parameters include the proliferation rate and death rate of uninfected HIV-targeted cells, the average number of virions produced by an infected cell, and the infection rate which is related to the antiviral treatment effect and is time-varying. To validate the estimation methods, we verified the identifiability of the HIV viral dynamic model and performed simulation studies. We applied the proposed techniques to estimate the key HIV viral dynamic parameters for two individual AIDS patients treated with antiretroviral therapies. We demonstrate that HIV viral dynamics can be well characterized and

Predictive value and efficiency of laboratory testing.

PubMed

Galen, R S

1980-11-01

Literature on determining reference values and reference intervals on "normal" or "healthy" individuals is abundant. It is impossible, however, to evaluate a data set of reference values and select a suitable reference interval that will be meaningful for the practice of medicine. The reference interval, no matter how derived statistically, tells us nothing about disease. This is the main reason the concepts of "normal values" have failed us and why "reference values" will prove similarly disappointing. By studying these same constituents in a variety of disease states as well, it will be possible to select "referent values" that will make the test procedure meaningful for diagnostic purposes. In order to obtain meaningful referent values for predicting disease, it is necessary to study not only the "healthy" reference population, but patients with the disease in question, and patients who are free of the disease in question but who have other diseases. Studies of this type are not frequently found for laboratory tests that are in common use today.

Elliptical varied line-space (EVLS) gratings

NASA Astrophysics Data System (ADS)

Thomas, Roger J.

2004-10-01

Imaging spectroscopy at wavelengths below 2000 Å offers an especially powerful method for studying many extended high-temperature astronomical objects, like the Sun and its outer layers. But the technology to make such measurements is also especially challenging, because of the poor reflectance of all standard materials at these wavelengths, and because the observation must be made from above the absorbing effects of the Earth's atmosphere. To solve these problems, single-reflection stigmatic spectrographs for XUV wavelengths have bee flown on several space missions based on designs with toroidal uniform line-space (TULS) or spherical varied line-space (SVLS) gratings that operate at near normal-incidence. More recently, three solar EUV/UV instruments have been selected that use toroidal varied line-space (TVLS) gratings; these are SUMI and RAISE, both sounding rocket payloads, and NEXUS, a SMEX satellite-mission. The next logical extension to such designs is the use of elliptical surfaces for varied line-space (EVLS) rulings. In fact, EVLS designs are found to provide superior imaging even at very large spectrograph magnifications and beam-speeds, permitting extremely high-quality performance in remarkably compact instrument packages. In some cases, such designs may be optimized even further by using a hyperbolic surface for the feeding telescope. The optical characteristics of two solar EUV spectrometers based on these concepts are described: EUS and EUI, both being developed as possible instruments for ESA's Solar Orbiter mission by consortia led by RAL and by MSSL, respectively.

An asymptotic formula for polynomials orthonormal with respect to a varying weight. II

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

Komlov, A V; Suetin, S P

2014-09-30

This paper gives a proof of the theorem announced by the authors in the preceding paper with the same title. The theorem states that asymptotically the behaviour of the polynomials which are orthonormal with respect to the varying weight e{sup −2nQ(x)}p{sub g}(x)/√(∏{sub j=1}{sup 2p}(x−e{sub j})) coincides with the asymptotic behaviour of the Nuttall psi-function, which solves a special boundary-value problem on the relevant hyperelliptic Riemann surface of genus g=p−1. Here e{sub 1}

Modeling the Value Recovery of Rare Earth Permanent Magnets at End-of-Life

DOE PAGES

Cong, Liang; Jin, Hongyue; Fitsos, Pete; ...

2015-05-21

Permanent magnets containing rare earth elements (REEs) such as Dysprosium and Neodymium offer an advantage over non-REE containing magnets (e.g. ferrite or AlNiCo) in terms of power relative to size. However, REE availability has varied significantly in recent years leading to volatility in the cost of rare earth permanent magnets (REPMs). The supply of REEs can be increased by recycling consumer products and industrial machinery that contain REPMs at product end-of-life (EOL). This paper discusses the REE recovery process for EOL products. The optimal dismantling of products is examined with an emphasis placed on obtaining used REPMs. The challenge ofmore » collecting, managing, transporting, and processing used products is addressed through the development of a cost model for REPM recovery. This model is used to investigate several EOL strategies for recovering REPMs. Sensitivity analysis is conducted to identify the key factors that influence value recovery economics. A hard disk drive serves as a case study for model demonstration.« less

Rheological behaviour of a suspension of microswimmers varying in motor characteristics

NASA Astrophysics Data System (ADS)

Tirumkudulu, Mahesh; Karmakar, Richa; Gulvady, Ranjit; Venkatesh, K. V.

2013-11-01

A suspension of motile cells exhibits complex rheological properties due to their collective motion. We measure the shear viscosity of suspensions of Escherichia coli strains varying in motor characteristics such as duration of run and tumble. At low cell densities, all strains irrespective of their motor characteristics exhibiting a linear increase in viscosity with cell density suggesting that the cells behave as a suspension of rods with an effective aspect ratio set by the motor characteristics of the bacteria. As the cell density is increased beyond a critical value, the viscosity drops sharply signaling the presence of strongly coordinated motion among bacteria. The critical density depends not only on the magnitude of shear but also the motor characteristics of individual cells. High shear rate disrupts the coordinated motion reducing its behavior, once again, to a suspension of inactive particles. The authors acknowldege financial support from Department of Science and Technology, India.

Time-varying metamaterials based on graphene-wrapped microwires: Modeling and potential applications

NASA Astrophysics Data System (ADS)

Salary, Mohammad Mahdi; Jafar-Zanjani, Samad; Mosallaei, Hossein

2018-03-01

The successful realization of metamaterials and metasurfaces requires the judicious choice of constituent elements. In this paper, we demonstrate the implementation of time-varying metamaterials in the terahertz frequency regime by utilizing graphene-wrapped microwires as building blocks and modulation of graphene conductivity through exterior electrical gating. These elements enable enhancement of light-graphene interaction by utilizing optical resonances associated with Mie scattering, yielding a large tunability and modulation depth. We develop a semianalytical framework based on transition-matrix formulation for modeling and analysis of periodic and aperiodic arrays of such time-varying building blocks. The proposed method is validated against full-wave numerical results obtained using the finite-difference time-domain method. It provides an ideal tool for mathematical synthesis and analysis of space-time gradient metamaterials, eliminating the need for computationally expensive numerical models. Moreover, it allows for a wider exploration of exotic space-time scattering phenomena in time-modulated metamaterials. We apply the method to explore the role of modulation parameters in the generation of frequency harmonics and their emerging wavefronts. Several potential applications of such platforms are demonstrated, including frequency conversion, holographic generation of frequency harmonics, and spatiotemporal manipulation of light. The presented results provide key physical insights to design time-modulated functional metadevices using various building blocks and open up new directions in the emerging paradigm of time-modulated metamaterials.

Design and optimization of mixed flow pump impeller blades by varying semi-cone angle

NASA Astrophysics Data System (ADS)

Dash, Nehal; Roy, Apurba Kumar; Kumar, Kaushik

2018-03-01

The mixed flow pump is a cross between the axial and radial flow pump. These pumps are used in a large number of applications in modern fields. For the designing of these mixed flow pump impeller blades, a lot number of design parameters are needed to be considered which makes this a tedious task for which fundamentals of turbo-machinery and fluid mechanics are always prerequisites. The semi-cone angle of mixed flow pump impeller blade has a specified range of variations generally between 45o to 60o. From the literature review done related to this topic researchers have considered only a particular semi-cone angle and all the calculations are based on this very same semi-cone angle. By varying this semi-cone angle in the specified range, it can be verified if that affects the designing of the impeller blades for a mixed flow pump. Although a lot of methods are available for designing of mixed flow pump impeller blades like inverse time marching method, the pseudo-stream function method, Fourier expansion singularity method, free vortex method, mean stream line theory method etc. still the optimized design of the mixed flow pump impeller blade has been a cumbersome work. As stated above since all the available research works suggest or propose the blade designs with constant semi-cone angle, here the authors have designed the impeller blades by varying the semi-cone angle in a particular range with regular intervals for a Mixed-Flow pump. Henceforth several relevant impeller blade designs are obtained and optimization is carried out to obtain the optimized design (blade with optimal geometry) of impeller blade.

Comparison of ophthalmic measurements obtained via high-frequency ultrasound imaging in four species of snakes.

PubMed

Hollingsworth, Steven R; Holmberg, Bradford J; Strunk, Anneliese; Oakley, Alicia D; Sickafoose, Leann M; Kass, Philip H

2007-10-01

To measure the dimensions of the eyes of living snakes by use of high-frequency ultrasound imaging and correlate those measurements with age, length, and weight. Animals-14 clinically normal snakes. Species, age, length, weight, and horizontal spectacle diameter were recorded, and each snake underwent physical and ophthalmic examinations; ultrasonographic examination of both eyes was performed by use of a commercially available ultrasound unit and a 50-MHz transducer. Ultrasonographic measurements included spectacle thickness, subspectacular space depth, corneal thickness, anterior chamber depth, lens thickness, vitreous cavity depth, and globe length. All measurements were made along the visual axis. 2 corn snakes, 5 California king snakes, 1 gopher snake, and 6 ball pythons were examined. There were no significant differences within or between the species with regard to mean spectacle thickness, corneal thickness, or subspectacular space depth. However, mean horizontal spectacle diameter, anterior chamber depth, and axial globe length differed among the 4 species; for each measurement, ball pythons had significantly larger values than California king snakes. Spectacle thickness, subspectacular space depth, and corneal thickness were similar among the species of snake examined and did not vary significantly with age, length, or weight. Measurements of these dimensions can potentially serve as baseline values to evaluate snakes of these species with a retained spectacle, subspectacular abscess, or subspectacular fluid accumulation. Anterior chamber depth and axial length appeared variable among species, but axial length did not vary with age, length, or weight in the species studied.

The role of utility value in achievement behavior: the importance of culture.

PubMed

Shechter, Olga G; Durik, Amanda M; Miyamoto, Yuri; Harackiewicz, Judith M

2011-03-01

Two studies tested how participants' responses to utility value interventions and subsequent interest in a math technique vary by culture (Westerners vs. East Asians) and levels of initial math interest. Participants in Study 1 were provided with information about the utility value of the technique or not. The manipulation was particularly effective for East Asian learners with initially lower math interest, who showed more interest in the technique relative to low-interest Westerners. Study 2 compared the effects of two types of utility value (proximal or distal) and examined the effects on interest, effort, performance, and process variables. Whereas East Asian participants reaped the most motivational benefits from a distal value manipulation, Westerners benefited the most from a proximal value manipulation. These findings have implications for how to promote motivation for learners with different cultural backgrounds and interests.

Values and public acceptability dimensions of sustainable egg production.

PubMed

Thompson, P B; Appleby, M; Busch, L; Kalof, L; Miele, M; Norwood, B F; Pajor, E

2011-09-01

The attributes of egg production that elicit values-based responses include the price and availability of eggs, environmental impacts, food safety or health concerns, and animal welfare. Different social groups have distinct interests regarding the sustainability of egg production that reflect these diverse values. Current scientifically based knowledge about how values and attitudes in these groups can be characterized is uneven and must be derived from studies conducted at varying times and using incomplete study methods. In general, some producer and consumer interests are translated through markets and are mediated by market mechanisms, whereas others are poorly reflected by economic behavior. An array of survey and focus group research has been performed to elicit consumer and activist beliefs about performance goals they would expect from an egg production system. These studies provide evidence that consumers' market behavior may be at odds with their ethical and political beliefs about performance goals.

Skill transfer specificity shapes perception and action under varying environmental constraints.

PubMed

Seifert, Ludovic; Wattebled, Léo; Orth, Dominic; L'Hermette, Maxime; Boulanger, Jérémie; Davids, Keith

2016-08-01

Using an ecological dynamics framework, this study investigated the generality and specificity of skill transfer processes in organisation of perception and action using climbing as a task vehicle. Fluency of hip trajectory and orientation was assessed using normalized jerk coefficients exhibited by participants as they adapted perception and action under varying environmental constraints. Twelve recreational climbers were divided into two groups: one completing a 10-m high route on an indoor climbing wall; a second undertaking a 10-m high route on an icefall in a top-rope condition. We maintained the same level of difficulty between these two performance environments. An inertial measurement unit was attached each climber's hips to collect 3D acceleration and 3D orientation data to compute jerk coefficient values. Video footage was used to record the ratio of exploratory/performatory movements. Results showed higher jerk coefficient values and number of exploratory movements for performance on the icefall route, perhaps due to greater functional complexity in perception and action required when climbing icefalls, which involves use of specific tools for anchorage. Findings demonstrated how individuals solve different motor problems, exploiting positive general transfer processes enabling participants to explore the pick-up of information for the perception of affordances specific to icefall climbing. Copyright © 2016 Elsevier B.V. All rights reserved.

Time-varying multiplex network: Intralayer and interlayer synchronization

NASA Astrophysics Data System (ADS)

Rakshit, Sarbendu; Majhi, Soumen; Bera, Bidesh K.; Sinha, Sudeshna; Ghosh, Dibakar

2017-12-01

A large class of engineered and natural systems, ranging from transportation networks to neuronal networks, are best represented by multiplex network architectures, namely a network composed of two or more different layers where the mutual interaction in each layer may differ from other layers. Here we consider a multiplex network where the intralayer coupling interactions are switched stochastically with a characteristic frequency. We explore the intralayer and interlayer synchronization of such a time-varying multiplex network. We find that the analytically derived necessary condition for intralayer and interlayer synchronization, obtained by the master stability function approach, is in excellent agreement with our numerical results. Interestingly, we clearly find that the higher frequency of switching links in the layers enhances both intralayer and interlayer synchrony, yielding larger windows of synchronization. Further, we quantify the resilience of synchronous states against random perturbations, using a global stability measure based on the concept of basin stability, and this reveals that intralayer coupling strength is most crucial for determining both intralayer and interlayer synchrony. Lastly, we investigate the robustness of interlayer synchronization against a progressive demultiplexing of the multiplex structure, and we find that for rapid switching of intralayer links, the interlayer synchronization persists even when a large number of interlayer nodes are disconnected.

Time-varying multiplex network: Intralayer and interlayer synchronization.

PubMed

Rakshit, Sarbendu; Majhi, Soumen; Bera, Bidesh K; Sinha, Sudeshna; Ghosh, Dibakar

2017-12-01

A large class of engineered and natural systems, ranging from transportation networks to neuronal networks, are best represented by multiplex network architectures, namely a network composed of two or more different layers where the mutual interaction in each layer may differ from other layers. Here we consider a multiplex network where the intralayer coupling interactions are switched stochastically with a characteristic frequency. We explore the intralayer and interlayer synchronization of such a time-varying multiplex network. We find that the analytically derived necessary condition for intralayer and interlayer synchronization, obtained by the master stability function approach, is in excellent agreement with our numerical results. Interestingly, we clearly find that the higher frequency of switching links in the layers enhances both intralayer and interlayer synchrony, yielding larger windows of synchronization. Further, we quantify the resilience of synchronous states against random perturbations, using a global stability measure based on the concept of basin stability, and this reveals that intralayer coupling strength is most crucial for determining both intralayer and interlayer synchrony. Lastly, we investigate the robustness of interlayer synchronization against a progressive demultiplexing of the multiplex structure, and we find that for rapid switching of intralayer links, the interlayer synchronization persists even when a large number of interlayer nodes are disconnected.

Toward Developing a Relative Value Scale for Medical and Surgical Services

PubMed Central

Hsiao, William C.; Stason, William B.

1979-01-01

A methodology has been developed to determine the relative values of surgical procedures and medical office visits on the basis of resource costs. The time taken to perform the service and the complexity of that service are the most critical variables. Interspecialty differences in the opportunity costs of training and overhead expenses are also considered. Results indicate some important differences between the relative values based on resource costs and existing standards, prevailing Medicare charges, and California Relative Value Study values. Most dramatic are discrepancies between existing reimbursement levels and resource cost values for office visits compared to surgical procedures. These vary from procedure to procedure and specialty to specialty but indicate that, on the average, office visits are undervalued (or surgical procedures overvalued) by four- to five-fold. After standardizing the variations in the complexity of different procedures, the hourly reimbursement rate in 1978 ranged from $40 for a general practitioner to $200 for surgical specialists. PMID:10309112

Genetic polymorphisms in varied environments.

PubMed

Powell, J R

1971-12-03

Thirteen experimenital populationis of Drosophila willistoni were maintained in cages, in some of which the environments were relatively constant and in others varied. After 45 weeks, the populations were assayed by gel electrophoresis for polymorphisms at 22 protein loci. The average heterozygosity per individual and the average unmber of alleles per locus were higher in populations maintained in heterogeneous environments than in populations in more constant enviroments.

On two special values of temperature factor in hypersonic flow stagnation point

NASA Astrophysics Data System (ADS)

Bilchenko, G. G.; Bilchenko, N. G.

2018-03-01

The hypersonic aircraft permeable cylindrical and spherical surfaces laminar boundary layer heat and mass transfer control mathematical model properties are investigated. The nonlinear algebraic equations systems are obtained for two special values of temperature factor in the hypersonic flow stagnation point. The mappings bijectivity between heat and mass transfer local parameters and controls is established. The computation experiments results are presented: the domains of allowed values “heat-friction” are obtained.

3-D loaded scaffolds obtained by supercritical CO2 assisted process

NASA Astrophysics Data System (ADS)

Cardea, S.; Reverchon, E.

2014-08-01

In this work, a supercritical CO2 (SC-CO2) drying process for the formation of 3-D PVDF-HFP loaded scaffolds was tested. Experiments at pressures ranging between 150 and 250 bar and at temperatures ranging between 35 and 55°C were performed. The PVDF-HFP- acetone-ethanol solution at 15% w/w polymer was selected as the base case. The drug (amoxicillin) concentration was varied from 20 to 30% w/w with respect to PVDF-HFP. SC- CO2 drying process was confirmed to be a valid alternative to generate loaded structures; indeed, scaffolds characterized by nanometric networks (with mean pore diameter of about 300 nm) with a homogeneous drug distribution were obtained. Drug controlled release experiments were also performed and a quasi-zero order release kinetic was observed.

Mass separation of deuterium and helium with conventional quadrupole mass spectrometer by using varied ionization energy

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

Yu, Yaowei; Hu, Jiansheng, E-mail: hujs@ipp.ac.cn; Wan, Zhao

2016-03-15

Deuterium pressure in deuterium-helium mixture gas is successfully measured by a common quadrupole mass spectrometer (model: RGA200) with a resolution of ∼0.5 atomic mass unit (AMU), by using varied ionization energy together with new developed software and dedicated calibration for RGA200. The new software is developed by using MATLAB with the new functions: electron energy (EE) scanning, deuterium partial pressure measurement, and automatic data saving. RGA200 with new software is calibrated in pure deuterium and pure helium 1.0 × 10{sup −6}–5.0 × 10{sup −2} Pa, and the relation between pressure and ion current of AMU4 under EE = 25 eVmore » and EE = 70 eV is obtained. From the calibration result and RGA200 scanning with varied ionization energy in deuterium and helium mixture gas, both deuterium partial pressures (P{sub D{sub 2}}) and helium partial pressure (P{sub He}) could be obtained. The result shows that deuterium partial pressure could be measured if P{sub D{sub 2}} > 10{sup −6} Pa (limited by ultimate pressure of calibration vessel), and helium pressure could be measured only if P{sub He}/P{sub D{sub 2}} > 0.45, and the measurement error is evaluated as 15%. This method is successfully employed in EAST 2015 summer campaign to monitor deuterium outgassing/desorption during helium discharge cleaning.« less

25 CFR 162.539 - Must I obtain a WEEL before obtaining a WSR lease?

Code of Federal Regulations, 2014 CFR

2014-04-01

... AND PERMITS Wind and Solar Resource Leases Wsr Leases § 162.539 Must I obtain a WEEL before obtaining... direct result of energy resource information gathered from a WEEL activity, obtaining a WEEL is not a...

25 CFR 162.539 - Must I obtain a WEEL before obtaining a WSR lease?

Code of Federal Regulations, 2013 CFR

2013-04-01

... AND PERMITS Wind and Solar Resource Leases Wsr Leases § 162.539 Must I obtain a WEEL before obtaining... direct result of energy resource information gathered from a WEEL activity, obtaining a WEEL is not a...

Varying potential silicon carbide gas sensor

NASA Technical Reports Server (NTRS)

Shields, Virgil B. (Inventor); Ryan, Margaret A. (Inventor); Williams, Roger M. (Inventor)

1997-01-01

A hydrocarbon gas detection device operates by dissociating or electro-chemically oxidizing hydrocarbons adsorbed to a silicon carbide detection layer. Dissociation or oxidation are driven by a varying potential applied to the detection layer. Different hydrocarbon species undergo reaction at different applied potentials so that the device is able to discriminate among various hydrocarbon species. The device can operate at temperatures between 100.degree. C. and at least 650.degree. C., allowing hydrocarbon detection in hot exhaust gases. The dissociation reaction is detected either as a change in a capacitor or, preferably, as a change of current flow through an FET which incorporates the silicon carbide detection layers. The silicon carbide detection layer can be augmented with a pad of catalytic material which provides a signal without an applied potential. Comparisons between the catalytically produced signal and the varying potential produced signal may further help identify the hydrocarbon present.

Exponential stability of impulsive stochastic genetic regulatory networks with time-varying delays and reaction-diffusion

DOE PAGES

Cao, Boqiang; Zhang, Qimin; Ye, Ming

2016-11-29

We present a mean-square exponential stability analysis for impulsive stochastic genetic regulatory networks (GRNs) with time-varying delays and reaction-diffusion driven by fractional Brownian motion (fBm). By constructing a Lyapunov functional and using linear matrix inequality for stochastic analysis we derive sufficient conditions to guarantee the exponential stability of the stochastic model of impulsive GRNs in the mean-square sense. Meanwhile, the corresponding results are obtained for the GRNs with constant time delays and standard Brownian motion. Finally, an example is presented to illustrate our results of the mean-square exponential stability analysis.