WorldWideScience

Sample records for variable importance measures

  1. Variable: Classification, Measurement and Importance in Social Science Research

    OpenAIRE

    Raiphea, Yow Peter

    2015-01-01

    Variable generally regarded as unit of analysis is defined by scholars in different ways. There is no fixed definition and classification of variable in research. In social science research variable played an important role in the formulation of hypothesis, increase clarity of research problem, in choosing what type of measurement scale to be used. Variable helped to avoid subjectivity and to bring about true picture of events or phenomena or behavior which the social science researchers are ...

  2. Alternative measure for education variable in an empirical economic growth model: Is primary education less important?

    OpenAIRE

    Tin-Chun Lin

    2006-01-01

    In this paper, an alternative measure of the education variable is proposed in an empirical economic growth model. Taiwan from 1964-2000 is selected as a case study. The main innovation of this paper is the weighting of education inputs by schooling level as an additional input into the application of production. Results reveal that primary education carries the greatest credits in Taiwan's economic development, which suggests that educators and policy makers value the importance of the found...

  3. Kernel-Based Measure of Variable Importance for Genetic Association Studies.

    Science.gov (United States)

    Gallego, Vicente; Luz Calle, M; Oller, Ramon

    2017-06-17

    The identification of genetic variants that are associated with disease risk is an important goal of genetic association studies. Standard approaches perform univariate analysis where each genetic variant, usually Single Nucleotide Polymorphisms (SNPs), is tested for association with disease status. Though many genetic variants have been identified and validated so far using this univariate approach, for most complex diseases a large part of their genetic component is still unknown, the so called missing heritability. We propose a Kernel-based measure of variable importance (KVI) that provides the contribution of a SNP, or a group of SNPs, to the joint genetic effect of a set of genetic variants. KVI can be used for ranking genetic markers individually, sets of markers that form blocks of linkage disequilibrium or sets of genetic variants that lie in a gene or a genetic pathway. We prove that, unlike the univariate analysis, KVI captures the relationship with other genetic variants in the analysis, even when measured at the individual level for each genetic variable separately. This is specially relevant and powerful for detecting genetic interactions. We illustrate the results with data from an Alzheimer's disease study and show through simulations that the rankings based on KVI improve those rankings based on two measures of importance provided by the Random Forest. We also prove with a simulation study that KVI is very powerful for detecting genetic interactions.

  4. DYSFUNCTION OF THE AUTONOMIC NERVOUS SYSTEM ASSOCIATED WITH EXCESSIVE ALCOHOL CONSUMPTION : IMPORTANCE OF MEASURING HEART RATE VARIABILITY

    OpenAIRE

    Lechevallier, Zina; Héron, Anne

    2017-01-01

    Ethanol has multiple effects on the cardiovascular system that can increase mortality, especially in chronic alcoholic patient. Some effects result from alcohol toxicity on autonomic nervous system. They may regress in case of abstinence and could be detected early. This review shows the importance of identifying cardiovascular dysautonomia by measuring heart rate variability which is reduced in such cases and represents a non-invasive tool of choice, to identify cardiovascular risks in alcoh...

  5. Variable importance in latent variable regression models

    NARCIS (Netherlands)

    Kvalheim, O.M.; Arneberg, R.; Bleie, O.; Rajalahti, T.; Smilde, A.K.; Westerhuis, J.A.

    2014-01-01

    The quality and practical usefulness of a regression model are a function of both interpretability and prediction performance. This work presents some new graphical tools for improved interpretation of latent variable regression models that can also assist in improved algorithms for variable

  6. Intraspecific variability: an important consideration in forming ...

    African Journals Online (AJOL)

    species of cyanobacteria, dinoflagellates, haptophytes, raphidophytes and diatoms. ... The available data underscore the importance of including multiple strains in research to advance understanding about toxigenic algal species and the importance of tempering conclusions to consider the potential for differences beyond ...

  7. Cell number as an important variable in optimising inoculum age ...

    African Journals Online (AJOL)

    The growth lag phase during microbial fermentation reduced productivity and equipment efficiency. Inoculum age and size were the two important variables considered in fermentation optimisation. Previous studies investigated these two variables separately, in contrast to the orthogonal or use of response surface ...

  8. Issues in Evaluating Importance Weighting in Quality of Life Measures

    Science.gov (United States)

    Hsieh, Chang-ming

    2013-01-01

    For most empirical research investigating the topic of importance weighting in quality of life (QoL) measures, the prevailing approach has been to use (1) a limited choice of global QoL measures as criterion variables (often a single one) to determine the performance of importance weighting, (2) a limited option of weighting methods to develop…

  9. Affect Variability is Constantly Important: Implications for Health

    OpenAIRE

    Jenkins, Brooke Nicole

    2017-01-01

    Positive and negative affect has been associated with numerous health factors. However, what is commonly investigated are the mean levels of affect. While means reveal important information, how affect varies over time may provide further information about how the experience of affect relates to important outcomes. This change from moment to moment, day to day, or week to week has been referred to as affect variability and is often operationally defined as the standard deviation of affect ove...

  10. Interpreting Multiple Linear Regression: A Guidebook of Variable Importance

    Science.gov (United States)

    Nathans, Laura L.; Oswald, Frederick L.; Nimon, Kim

    2012-01-01

    Multiple regression (MR) analyses are commonly employed in social science fields. It is also common for interpretation of results to typically reflect overreliance on beta weights, often resulting in very limited interpretations of variable importance. It appears that few researchers employ other methods to obtain a fuller understanding of what…

  11. Measurement Decision Risk - The Importance of Definitions

    Science.gov (United States)

    Mimbs, Scott M.

    2008-01-01

    One of the more misunderstood areas of metrology is the Test Uncertainty Ratio (TUR) and the Test Accuracy Ratio (TAR). There have been many definitions over the years, but why are these definitions important to a discussion on measurement decision risk? The importance lies in the clarity of communication. Problems can immediately arise in the application (or misapplication) of the definition of these terms. In other words, while it is important to understand the definitions, it is more important to understand concepts behind the definitions and to be precise in how they are applied. The objective of any measurement is a decision. Measurement Decision Risk is a way to look at the quality of a measurement, and although it is not a new concept, it has generated a lot of attention since its addition as a requirement in the new U.S. National Standard, ANSIINCSL Z540.3-2006. In addition to Measurement Decision Risk as the prime method of managing measurement risk, Z540.3 has added, as a fall-back, an explicit definition for TUR. The impact these new requirements may have on calibration service providers has become the topic of much discussion and in some cases concern. This paper will look at the concepts behind the definitions and how they relate to Measurement Decision Risk. Using common examples, this paper will also provide a comparison of various elements of risk related to measurement science using the concepts of TAR, TUR, accuracy ratios, and Consumer Risk (False Accept Risk). The goal of this paper is to provide a better understanding of their relevance to the measurement decision process.

  12. Additive measures of travel time variability

    DEFF Research Database (Denmark)

    Engelson, Leonid; Fosgerau, Mogens

    2011-01-01

    This paper derives a measure of travel time variability for travellers equipped with scheduling preferences defined in terms of time-varying utility rates, and who choose departure time optimally. The corresponding value of travel time variability is a constant that depends only on preference...... parameters. The measure is unique in being additive with respect to independent parts of a trip. It has the variance of travel time as a special case. Extension is provided to the case of travellers who use a scheduled service with fixed headway....

  13. The Importance of Landfill Gas Policy Measures

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    The purpose of this document is to identify and examine global policies, measures, and incentives that appear to be stimulating LFG use. As certain countries have made great advances in LFGE development through effective policies, the intention of this report is to use information from the IEA's Global Renewable Energy and Energy Efficiency Measures and Policies Databases to identify and discuss policies. By consolidating this information and categorising it according to policy type, the attributes that are most appealing or applicable to the circumstances of a particular country or area -- technology demonstration, financial incentives, awareness campaigns, etc. -- are more easily identified. The report begins with background information on LFG and sanitary landfill practices, including a discussion of regional disparities, followed by a description of LFG mitigation technologies. Barriers to LFGE projects are then outlined. An explanation of the importance and effectiveness of policy measures leads into a discussion of types and examples of measures that are being used to overcome these barriers and encourage LFGE development. The report concludes with lessons learned, recommendations for further study, and resources where more information can be found.

  14. Measure of Psychological Variables in Dancers Sport

    OpenAIRE

    Cantón, Enrique; Universidad de Valencia; Checa, Irene; Centro de Psicologia Teseo

    2012-01-01

    The aim of this study is to identify and assess key psychological variables are intervening at different levels of performance in sport dance practice. For this reason, among others, was used the “Cuestionario de Características Psicológicas aplicadas al Rendimiento Deportivo” (Gimeno, Buceta & Pérez-Llantada, 2001). Carrying out an analysis of variance, although not reaching statistically significant differences in the factors Stress Management and Influence of Performance Measurement, if we...

  15. Selection of Important Variables in Principal Component Analysis ...

    African Journals Online (AJOL)

    While the criterion (M2) based on Procrustes Analysis, found in literature, identifies structure-bearing variables, particularly for grouped data, the proposed criteria retain those variables that preserve the maximum sample variation and carry whatever unknown multivariate structure, which may be present in the complete ...

  16. Blood pressure variability: a novel and important risk factor.

    Science.gov (United States)

    Floras, John S

    2013-05-01

    Blood pressure is a continuous, not a static, variable. Individuals exhibiting similar clinic or home blood pressure can differ considerably with respect to their average day and nighttime values, beat-by-beat blood pressure variation during wakefulness and sleep, responses to mental and physical stimuli, and intersession and seasonal variation. There now is evidence that several such representations of blood pressure variability, if augmented, increase cardiovascular risk independent of the average of conventionally acquired blood pressure readings. As well, recent retrospective analyses of published trial data have concluded that antihypertensive drug classes differ in their effects on intersession blood pressure variability and associated risk of stroke. If the goal of the hypertension community is to optimize personalized cardiovascular risk assessment and to attenuate fully such risk, future efforts should be directed at determining which representation of blood pressure variability estimates individual cardiovascular risk best, establishing "normal" and "high- risk" variability distributions, testing the hypothesis that attenuating such variability specifically through drug or device therapy reduces cardiovascular risk more than blood pressure reduction per se, and integrating such data into clinical practice. Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  17. Variable importance and prediction methods for longitudinal problems with missing variables.

    Directory of Open Access Journals (Sweden)

    Iván Díaz

    Full Text Available We present prediction and variable importance (VIM methods for longitudinal data sets containing continuous and binary exposures subject to missingness. We demonstrate the use of these methods for prognosis of medical outcomes of severe trauma patients, a field in which current medical practice involves rules of thumb and scoring methods that only use a few variables and ignore the dynamic and high-dimensional nature of trauma recovery. Well-principled prediction and VIM methods can provide a tool to make care decisions informed by the high-dimensional patient's physiological and clinical history. Our VIM parameters are analogous to slope coefficients in adjusted regressions, but are not dependent on a specific statistical model, nor require a certain functional form of the prediction regression to be estimated. In addition, they can be causally interpreted under causal and statistical assumptions as the expected outcome under time-specific clinical interventions, related to changes in the mean of the outcome if each individual experiences a specified change in the variable (keeping other variables in the model fixed. Better yet, the targeted MLE used is doubly robust and locally efficient. Because the proposed VIM does not constrain the prediction model fit, we use a very flexible ensemble learner (the SuperLearner, which returns a linear combination of a list of user-given algorithms. Not only is such a prediction algorithm intuitive appealing, it has theoretical justification as being asymptotically equivalent to the oracle selector. The results of the analysis show effects whose size and significance would have been not been found using a parametric approach (such as stepwise regression or LASSO. In addition, the procedure is even more compelling as the predictor on which it is based showed significant improvements in cross-validated fit, for instance area under the curve (AUC for a receiver-operator curve (ROC. Thus, given that 1 our VIM

  18. The importance of measuring household sector innovation

    NARCIS (Netherlands)

    de Jong, J.P.J.

    Empirical evidence shows that consumers can innovate as well as producers They spend considerable time and money and collaboratively develop substantial projects, which enhance social welfare. Household sector innovation is also important in developing countries. We summarize recent insights on how

  19. The importance of local measurements for cosmology

    CERN Document Server

    Verde, Licia; Jimenez, Raul

    2013-01-01

    We explore how local, cosmology-independent measurements of the Hubble constant and the age of the Universe help to provide a powerful consistency check of the currently favored cosmological model (flat LambdaCDM) and model-independent constraints on cosmology. We use cosmic microwave background (CMB) data to define the model-dependent cosmological parameters, and add local measurements to assess consistency and determine whether extensions to the model are justified. At current precision, there is no significant tension between the locally measured Hubble constant and age of the Universe (with errors of 3% and 5% respectively) and the corresponding parameters derived from the CMB. However, if errors on the local measurements could be decreased by a factor of two, one could decisively conclude if there is tension or not. We also compare the local and CMB data assuming simple extensions of the flat, $\\Lambda$CDM model (including curvature, dark energy with a constant equation of state parameter not equal to -1...

  20. Importance of predictor variables for models of chemical function

    Data.gov (United States)

    U.S. Environmental Protection Agency — Importance of random forest predictors for all classification models of chemical function. This dataset is associated with the following publication: Isaacs , K., M....

  1. The active liquid Earth - importance of temporal and spatial variability

    Science.gov (United States)

    Arheimer, Berit

    2016-04-01

    The Planet Earth is indeed liquid and active - 71 percent of its surface is water-covered and this water never rests. Thanks to the water cycle, our planet's water supply is constantly moving from one place to another and from one form to another. Only 2.5% of the water is freshwater and it exists in the air as water vapor; it hits the ground as rain and snow; it flows on the surface from higher to lower altitudes in rivers, lakes, and glaciers; and it flows in the ground in soil, aquifers, and in all living organisms until it reaches the sea. On its way over the Earth's crust, some returns quickly to vapor again, while some is trapped and exposed to many "fill and spill" situations for a long journey. The variability in the water balance is crucial for hydrological understanding and modelling. The water cycle may appear simple, but magnitudes and rates in fluxes are very different from one place to another, resulting from variable drivers such as solar energy, precipitation and gravity in co-evolution with geology, soil, vegetation and fauna. The historical evolution, the temporal fluxes and diversity in space continue to fascinate hydrological scientists. Specific physical processes may be well known, but their boundary conditions, interactions and rate often remain unknown at a specific site and are difficult to monitor in nature. This results in mysterious features where trends in drivers do not match runoff, like the Sahelian Paradox or discharge to the Arctic Ocean. Humans have always interfered with the water cycle and engineering is fundamental for water regulation and re-allocation. Some 80% of the river flow from the northern part of the Earth is affected by fragmentation of the river channels by dams. In water management, there is always a tradeoff between upstream and downstream activities, not only regarding total water quantities but also for temporal patterns and water quality aspects. Sharing a water resource can generate conflicts but geopolitical

  2. A perspective demonstration on the importance of variable selection in inverse calibration for complex analytical systems.

    Science.gov (United States)

    Yun, Yong-Huan; Liang, Yi-Zeng; Xie, Gui-Xiang; Li, Hong-Dong; Cao, Dong-Sheng; Xu, Qing-Song

    2013-11-07

    Classical calibration and inverse calibration are two kinds of multivariate calibration in chemical modeling. They use strategies of modeling in component spectral space and in measured variable space, respectively. However, the intrinsic difference between these two calibration models is not fully investigated. Besides, in the case of complex analytical systems, the net analyte signal (NAS) cannot be well defined in inverse calibration due to the existence of uninformative and/or interfering variables. Therefore, application of the NAS cannot improve the predictive performance for this kind of calibration, since it is essentially a technique based on the full-spectrum. From our perspective, variable selection can significantly improve the predictive performance through removing uninformative and/or interfering variables. Although the need for variable selection in the inverse calibration model has already been experimentally demonstrated, it has not aroused so much attention. In this study, we first clarify the intrinsic difference between these two calibration models and then use a new perspective to intrinsically prove the importance of variable selection in the inverse calibration model for complex analytical systems. In addition, we have experimentally validated our viewpoint through the use of one UV dataset and two generated near infrared (NIR) datasets.

  3. Variable Bone Density of Scaphoid: Importance of Subchondral Screw Placement.

    Science.gov (United States)

    Swanstrom, Morgan M; Morse, Kyle W; Lipman, Joseph D; Hearns, Krystle A; Carlson, Michelle G

    2018-02-01

    Background  Ideal internal fixation of the scaphoid relies on adequate bone stock for screw purchase; so, knowledge of regional bone density of the scaphoid is crucial. Questions/Purpose  The purpose of this study was to evaluate regional variations in scaphoid bone density. Materials and Methods  Three-dimensional CT models of fractured scaphoids were created and sectioned into proximal/distal segments and then into quadrants (volar/dorsal/radial/ulnar). Concentric shells in the proximal and distal pole were constructed in 2-mm increments moving from exterior to interior. Bone density was measured in Hounsfield units (HU). Results  Bone density of the distal scaphoid (453.2 ± 70.8 HU) was less than the proximal scaphoid (619.8 ± 124.2 HU). There was no difference in bone density between the four quadrants in either pole. In both the poles, the first subchondral shell was the densest. In both the proximal and distal poles, bone density decreased significantly in all three deeper shells. Conclusion  The proximal scaphoid had a greater density than the distal scaphoid. Within the poles, there was no difference in bone density between the quadrants. The subchondral 2-mm shell had the greatest density. Bone density dropped off significantly between the first and second shell in both the proximal and distal scaphoids. Clinical Relevance  In scaphoid fracture ORIF, optimal screw placement engages the subchondral 2-mm shell, especially in the distal pole, which has an overall lower bone density, and the second shell has only two-third the density of the first shell.

  4. CTreconSIM - a simulator of reconstruction induced measurement variability

    DEFF Research Database (Denmark)

    Miles, James Edward

    2015-01-01

    VBA macro to model the effect of inter-reconstruction variability on orthopaedic measurements made from CT scans.......VBA macro to model the effect of inter-reconstruction variability on orthopaedic measurements made from CT scans....

  5. Important meteorological variables for statistical long-term air quality prediction in eastern China

    Science.gov (United States)

    Zhang, Libo; Liu, Yongqiang; Zhao, Fengjun

    2017-09-01

    Weather is an important factor for air quality. While there have been increasing attentions to long-term (monthly and seasonal) air pollution such as regional hazes from land-clearing fires during El Niño, the weather-air quality relationships are much less understood at long-term than short-term (daily and weekly) scales. This study is aimed to fill this gap through analyzing correlations between meteorological variables and air quality at various timescales. A regional correlation scale was defined to measure the longest time with significant correlations at a substantial large number of sites. The air quality index (API) and five meteorological variables during 2001-2012 at 40 eastern China sites were used. The results indicate that the API is correlated to precipitation negatively and air temperature positively across eastern China, and to wind, relative humidity and air pressure with spatially varied signs. The major areas with significant correlations vary with meteorological variables. The correlations are significant not only at short-term but also at long-term scales, and the important variables are different between the two types of scales. The concurrent regional correlation scales reach seasonal at p air temperature and relative humidity. Precipitation, which was found to be the most important variable for short-term air quality conditions, and air pressure are not important for long-term air quality. The lagged correlations are much smaller in magnitude than the concurrent correlations and their regional correction scales are at long term only for wind speed and relative humidity. It is concluded that wind speed should be considered as a primary predictor for statistical prediction of long-term air quality in a large region over eastern China. Relative humidity and temperature are also useful predictors but at less significant levels.

  6. Preanalytical factors of importance for measurement of Chromogranin A.

    Science.gov (United States)

    Pedersen, Lise; Nybo, Mads

    2014-09-25

    Studies indicate that fasting and diurnal variation can influence serum Chromogranin A (CgA) concentrations and furthermore, stability of the CgA molecule has been questioned. We investigated the impact of pre-analytical conditions on a CgA assay. Serum CgA concentrations were measured in blood samples collected from ten healthy subjects at three time points during three days with and without fasting. Samples were kept at 4°C and re-measured after 24 and 48 h in order to test the stability of the measured epitopes. For establishment of a reference interval, serum samples were collected from 120 healthy individuals. Serum CgA concentrations did not vary between fasting and non-fasting individuals (p=0.74), nor between gender (p=0.66). The analytical imprecision was 4.3%, the within-subject variability was 11.9%, while the between-subject variability was as high as 50.2%. Serum CgA concentrations measured during the day did however not differ (p=0.30). Of importance, re-analysis at 4°C showed significant decay in the CgA concentrations after 24 h (mean decrease 15.6%) and 48 h (mean decrease 44%). The median CgA concentration in 120 healthy subjects was 41.2 ng/mL with a reference interval of 30.3-94.4 ng/mL (2.5-97.5 percentile). Fasting does not influence CgA concentrations significantly, while sample stability is a major issue with the assay tested. The biological variation of CgA was defined and a reference interval was established. Copyright © 2014. Published by Elsevier B.V.

  7. Measurement and Modeling of Solar and PV Output Variability: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, M.

    2011-04-01

    This paper seeks to understand what temporal and spatial scales of variability in global horizontal radiation are important to a PV plants and what measurements are needed to be able to characterize them. As solar radiation measuring instruments are point receivers it is important to understand how those measurements translate to energy received over a larger spatial extent. Also of importance is the temporal natural of variability over large spatial areas. In this research we use high temporal and spatial resolution measurements from multiple sensors at a site in Hawaii to create solar radiation fields at various spatial and temporal scales. Five interpolation schemes were considered and the high resolution solar fields were converted to power production for a PV power plant. It was found that the interpolation schemes are robust and create ramp distributions close to what would be computed if the average solar radiation field was used. We also investigated the possibility of using time averaged solar data from 1 sensor to recreate the ramp distribution from the 17 sensors. It was found that the ramping distribution from using appropriately time averaged data from 1 sensor can reasonably match the distribution created using the 17 sensor network.

  8. Variability of Fusion Vergence Measurements in Heterophoria.

    Science.gov (United States)

    Costa Lança, Carla; Rowe, Fiona J

    2016-06-01

    The aims of this study were to compare fusional vergence measurements between orthophoria, esophoria, and exophoria, and to determine the strength of correlations between fusional convergence and divergence and angle of deviation. A cross-sectional study was performed in children with best-corrected visual acuity of 0.0 LogMAR in either eye, compensated heterophoria within 10 prism diopters (PD), full ocular rotations, presence of fusional vergence, and stereopsis (60 seconds of arc or better). Fusional amplitudes were compared between orthophoric and heterophoric children. The fusion reserve ratio was determined as compensating vergence divided by alternating cover test. Five hundred and thirty children (7.66±1.20 years) were recruited to this study. The most common heterophoria was exophoria (n=181, 34.2% for near; n=20, 3.8% for distance). Exophoric children had significant lower mean positive fusional vergences (exophoria-orthophoria: P=0.003; exophoria-esophoria: P=0.035) for near (19.54±5.23 base-out) compared with children with orthophoria (20.48±4.83 base-out) and esophoria (22.27±5.60 base-out). Smaller convergence fusion amplitudes were associated with larger angles of deviation at near (rs=-0.115; P=0.008) and lower fusion reserve ratios were associated with larger angles of deviation at distance (rs=-0.848; PVergence measurements, taking into consideration the baseline heterophoria, give important information about the ability of the patient to increase their vergence demand and maintain ocular alignment.

  9. [Variable measurement in urologic clinical research].

    Science.gov (United States)

    Fernández Pérez, Cristina; Coll Torres, Elisabeth; Barreales Tolosa, Laura

    2003-01-01

    Epidemiology develops measurements that allow to quantify the occurrence of disease within the population. There are three types of measurements: frequency measurements, explained in this article; association measurements, between the occurrence of disease and some characteristics, the effect of which on the disease is what they intend to measure; and measurements of the potential impact that modification or disappearance of some risk factors would have on the occurrence of disease in the population. The first objective of epidemiological studies is the knowledge of the frequency of disease. There are three basic measurements of frequency of a disease. Prevalence measures the proportion of people that has it in a given moment. Cumulative incidence measures the proportion of people that convert from non-sick individual to sick individual during a specified period of time. Incidence rate is a measure of the instantaneous strength of occurrence of the disease.

  10. Importance of fruit variability in the assessment of apple quality by sensory evaluation

    DEFF Research Database (Denmark)

    Bavay, Cécile; Symoneaux, Ronan; Maître, Isabelle

    2013-01-01

    the problem of handling variation due to fruit variability and assessor differences. The aim of this study was to investigate the weight of within-batch variability in sensory evaluation of apples and to propose a methodology that accounts for this variability. Prior to sensory analysis, for three apple...... hierarchical model for the analysis of the sensory data was proposed to measure the contribution of fruit variability to the variability of sensory scores. The results showed the efficiency of the model in quantifying within-batch variability. Fruit sampling and presentation methods as well as data handling...

  11. A complex network-based importance measure for mechatronics systems

    Science.gov (United States)

    Wang, Yanhui; Bi, Lifeng; Lin, Shuai; Li, Man; Shi, Hao

    2017-01-01

    In view of the negative impact of functional dependency, this paper attempts to provide an alternative importance measure called Improved-PageRank (IPR) for measuring the importance of components in mechatronics systems. IPR is a meaningful extension of the centrality measures in complex network, which considers usage reliability of components and functional dependency between components to increase importance measures usefulness. Our work makes two important contributions. First, this paper integrates the literature of mechatronic architecture and complex networks theory to define component network. Second, based on the notion of component network, a meaningful IPR is brought into the identifying of important components. In addition, the IPR component importance measures, and an algorithm to perform stochastic ordering of components due to the time-varying nature of usage reliability of components and functional dependency between components, are illustrated with a component network of bogie system that consists of 27 components.

  12. Bayesian modeling of measurement error in predictor variables

    NARCIS (Netherlands)

    Fox, Gerardus J.A.; Glas, Cornelis A.W.

    2003-01-01

    It is shown that measurement error in predictor variables can be modeled using item response theory (IRT). The predictor variables, that may be defined at any level of an hierarchical regression model, are treated as latent variables. The normal ogive model is used to describe the relation between

  13. Importance Is Not Unimportant: The Role of Importance Weighting in QOL Measures

    Science.gov (United States)

    Hsieh, Chang-Ming

    2012-01-01

    The effect of relative domain importance as a weighting mechanism in quality of life (QoL) measures has been a topic of debate for decades. Studies investigating the role of domain importance in QoL measures have produced mixed results. The mixed results may very well be the consequences of a limited choice of global satisfaction or QoL measures,…

  14. Importance of coastal change variables in determining vulnerability to sea- and lake-level change

    Science.gov (United States)

    Pendleton, E.A.; Thieler, E.R.; Williams, S.J.

    2010-01-01

    In 2001, the U.S. Geological Survey began conducting scientific assessments of coastal vulnerability to potential future sea- and lake-level changes in 22 National Park Service sea- and lakeshore units. Coastal park units chosen for the assessment included a variety of geological and physical settings along the U.S. Atlantic, Pacific, Gulf of Mexico, Gulf of Alaska, Caribbean, and Great Lakes shorelines. This research is motivated by the need to understand and anticipate coastal changes caused by accelerating sea-level rise, as well as lake-level changes caused by climate change, over the next century. The goal of these assessments is to provide information that can be used to make long-term (decade to century) management decisions. Here we analyze the results of coastal vulnerability assessments for several coastal national park units. Index-based assessments quantify the likelihood that physical changes may occur based on analysis of the following variables: tidal range, ice cover, wave height, coastal slope, historical shoreline change rate, geomorphology, and historical rate of relative sea- or lake-level change. This approach seeks to combine a coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, and it provides a measure of the system's potential vulnerability to the effects of sea- or lake-level change. Assessments for 22 park units are combined to evaluate relationships among the variables used to derive the index. Results indicate that Atlantic and Gulf of Mexico parks have the highest vulnerability rankings relative to other park regions. A principal component analysis reveals that 99% of the index variability can be explained by four variables: geomorphology, regional coastal slope, water-level change rate, and mean significant wave height. Tidal range, ice cover, and historical shoreline change are not as important when the index is evaluated at large spatial scales (thousands of kilometers

  15. Prognostic importance of glycaemic variability on hospital mortality in patients hospitalised in Internal Medicine Departments.

    Science.gov (United States)

    Sáenz-Abad, D; Gimeno-Orna, J A; Pérez-Calvo, J I

    2015-12-01

    The objective was to assess the prognostic importance of various glycaemic control measures on hospital mortality. Retrospective, analytical cohort study that included patients hospitalised in internal medicine departments with a diagnosis related to diabetes mellitus (DM), excluding acute decompensations. The clinical endpoint was hospital mortality. We recorded clinical, analytical and glycaemic control-related variables (scheduled insulin administration, plasma glycaemia at admission, HbA1c, mean glycaemia (MG) and in-hospital glycaemic variability and hypoglycaemia). The measurement of hospital mortality predictors was performed using univariate and multivariate logistic regression. A total of 384 patients (50.3% men) were included. The mean age was 78.5 (SD, 10.3) years. The DM-related diagnoses were type 2 diabetes (83.6%) and stress hyperglycaemia (6.8%). Thirty-one (8.1%) patients died while in hospital. In the multivariate analysis, the best model for predicting mortality (R(2)=0.326; P<.0001) consisted, in order of importance, of age (χ(2)=8.19; OR=1.094; 95% CI 1.020-1.174; P=.004), Charlson index (χ(2)=7.28; OR=1.48; 95% CI 1.11-1.99; P=.007), initial glycaemia (χ(2)=6.05; OR=1.007; 95% CI 1.001-1.014; P=.014), HbA1c (χ(2)=5.76; OR=0.59; 95% CI 0.33-1; P=.016), glycaemic variability (χ(2)=4.41; OR=1.031; 95% CI 1-1.062; P=.036), need for corticosteroid treatment (χ(2)=4.03; OR=3.1; 95% CI 1-9.64; P=.045), administration of scheduled insulin (χ(2)=3.98; OR=0.26; 95% CI 0.066-1; P=.046) and systolic blood pressure (χ(2)=2.92; OR=0.985; 95% CI 0.97-1.003; P=.088). An increase in initial glycaemia and in-hospital glycaemic variability predict the risk of mortality for hospitalised patients with DM. Copyright © 2015 Elsevier España, S.L.U. y Sociedad Española de Medicina Interna (SEMI). All rights reserved.

  16. The cost of travel time variability: three measures with properties

    DEFF Research Database (Denmark)

    Engelson, Leonid; Fosgerau, Mogens

    2016-01-01

    This paper explores the relationships between three types of measures of the cost of travel time variability: measures based on scheduling preferences and implicit departure time choice, Bernoulli type measures based on a univariate function of travel time, and mean-dispersion measures. We...

  17. Improving Attribute-Importance Measurement : a Reference-Point Approach

    NARCIS (Netherlands)

    Ittersum, van K.; Pennings, J.M.E.; Wansink, B.; Trijp, van J.C.M.

    2004-01-01

    Despite the importance of identifying the hierarchy of product attributes that drive judgment and choice, the many available methods remain limited regarding their convergent validity and test-retest reliability. To increase the validity and reliability of attribute-importance measurement, we focus

  18. The Relative Importance of Job Factors: A New Measurement Approach.

    Science.gov (United States)

    Nealey, Stanley M.

    This paper reports on a new two-phase measurement technique that permits a direct comparison of the perceived relative importance of economic vs. non-economic factors in a job situation in accounting for personnel retention, the willingness to produce, and job satisfaction. The paired comparison method was used to measure the preferences of 91…

  19. Clinical Trials With Large Numbers of Variables: Important Advantages of Canonical Analysis.

    Science.gov (United States)

    Cleophas, Ton J

    2016-01-01

    Canonical analysis assesses the combined effects of a set of predictor variables on a set of outcome variables, but it is little used in clinical trials despite the omnipresence of multiple variables. The aim of this study was to assess the performance of canonical analysis as compared with traditional multivariate methods using multivariate analysis of covariance (MANCOVA). As an example, a simulated data file with 12 gene expression levels and 4 drug efficacy scores was used. The correlation coefficient between the 12 predictor and 4 outcome variables was 0.87 (P = 0.0001) meaning that 76% of the variability in the outcome variables was explained by the 12 covariates. Repeated testing after the removal of 5 unimportant predictor and 1 outcome variable produced virtually the same overall result. The MANCOVA identified identical unimportant variables, but it was unable to provide overall statistics. (1) Canonical analysis is remarkable, because it can handle many more variables than traditional multivariate methods such as MANCOVA can. (2) At the same time, it accounts for the relative importance of the separate variables, their interactions and differences in units. (3) Canonical analysis provides overall statistics of the effects of sets of variables, whereas traditional multivariate methods only provide the statistics of the separate variables. (4) Unlike other methods for combining the effects of multiple variables such as factor analysis/partial least squares, canonical analysis is scientifically entirely rigorous. (5) Limitations include that it is less flexible than factor analysis/partial least squares, because only 2 sets of variables are used and because multiple solutions instead of one is offered. We do hope that this article will stimulate clinical investigators to start using this remarkable method.

  20. Metabolic Syndrome and Importance of Associated Variables in Children and Adolescents in Guabiruba - SC, Brazil

    Directory of Open Access Journals (Sweden)

    Nilton Rosini

    2015-07-01

    Full Text Available Background:The risk factors that characterize metabolic syndrome (MetS may be present in childhood and adolescence, increasing the risk of cardiovascular disease in adulthood.Objective:Evaluate the prevalence of MetS and the importance of its associated variables, including insulin resistance (IR, in children and adolescents in the city of Guabiruba-SC, Brazil.Methods:Cross-sectional study with 1011 students (6–14 years, 52.4% girls, 58.5% children. Blood samples were collected for measurement of biochemical parameters by routine laboratory methods. IR was estimated by the HOMA-IR index, and weight, height, waist circumference and blood pressure were determined. Multivariate logistic regression models were used to examine the associations between risk variables and MetS.Results:The prevalence of MetS, IR, overweight and obesity in the cohort were 14%, 8.5%, 21% and 13%, respectively. Among students with MetS, 27% had IR, 33% were overweight, 45.5% were obese and 22% were eutrophic. IR was more common in overweight (48% and obese (41% students when compared with eutrophic individuals (11%; p = 0.034. The variables with greatest influence on the development of MetS were obesity (OR = 32.7, overweight (OR = 6.1, IR (OR = 4.4; p ≤ 0.0001 for all and age (OR = 1.15; p = 0.014.Conclusion:There was a high prevalence of MetS in children and adolescents evaluated in this study. Students who were obese, overweight or insulin resistant had higher chances of developing the syndrome.

  1. Streamlining air import operations by trade facilitation measures

    Directory of Open Access Journals (Sweden)

    Yuri da Cunha Ferreira

    2017-12-01

    Full Text Available Global operations are subject to considerable uncertainties. Due to the Trade Facilitation Agreement that became effective in February 2017, the study of measures to streamline customs controls is urgent. This study aims to assess the impact of trade facilitation measures on import flows. An experimental study was performed in the largest cargo airport in South America through discrete-event simulation and design of experiments. Operation impacts of three trade facilitation measures are assessed on import flow by air. We shed light in the following trade facilitation measures: the use of X-ray equipment for physical inspection; increase of the number of qualified companies in the trade facilitation program; performance targets for customs officials. All trade facilitation measures used indicated potential to provide more predictability, cost savings, time reduction, and increase in security in international supply chain.

  2. MEASUREMENT OPTIMALIZATION OF ZAKAT DISTRIBUTION AT LEMBAGA AMIL ZAKAT USING VARIABLE MEASUREMENT OF ECONOMY

    Directory of Open Access Journals (Sweden)

    Marissa Haque

    2016-08-01

    Full Text Available The aim of this research conducted is to optimalize the zakat distribution using economy variabel measurement. Design/Metodology. The Quantitative Research Method is used to analyze financial data, with Optimalize Model as Z variable design, Measurement of Economy as Y variable and Objective Output as X variable, using AMOS program and SEM as tool analysis to confirm that the model can be used as a measurement tool. Research result. Using some indicators to analyze every variable, obtaining output and objective result, influence optimalization of measurement of economy. Conclusion. The measurement of optimalization of zakat distribution using measurement of economy variable, with independent variable/output exogenous and objective, can be used as a model to measure Lembaga Amil Zakat performance. Furthermore, this research need to have some indicators’ development especially in the area of objective variable.

  3. Importance measures in reliability, risk, and optimization principles and applications

    CERN Document Server

    Kuo, Way

    2012-01-01

    This unique treatment systematically interprets a spectrum of importance measures to provide a comprehensive overview of their applications in the areas of reliability, network, risk, mathematical programming, and optimization. Investigating the precise relationships among various importance measures, it describes how they are modelled and combined with other design tools to allow users to solve readily many real-world, large-scale decision-making problems.  Presenting the state-of-the-art in network analysis, multistate systems, and application in modern systems, this book offers a c

  4. IMPORTANCE OF KINETIC MEASURES IN TRAJECTORY PREDICTION WITH OPTIMAL CONTROL

    Directory of Open Access Journals (Sweden)

    Ömer GÜNDOĞDU

    2001-02-01

    Full Text Available A two-dimensional sagittally symmetric human-body model was established to simulate an optimal trajectory for manual material handling tasks. Nonlinear control techniques and genetic algorithms were utilized in the optimizations to explore optimal lifting patterns. The simulation results were then compared with the experimental data. Since the kinetic measures such as joint reactions and moments are vital parameters in injury determination, the importance of comparing kinetic measures rather than kinematical ones was emphasized.

  5. The importance and challenges of measuring work hours

    OpenAIRE

    Stewart, Jay

    2014-01-01

    Work hours are key components in estimating productivity growth and hourly wages as well as being a useful cyclical indicator in their own right, so measuring them correctly is important. The US Bureau of Labor Statistics (BLS) collects data on work hours in several surveys and publishes three widely-used series that measure average weekly hours. The series tell different stories about average weekly hours and trends in those hours but qualitatively similar stories about the cyclical behavior...

  6. Methane emissions in the Pantanal, South America, during the low water season - importance of environmental variables and within-lake variability

    Science.gov (United States)

    Bastviken, David; Santoro, Ana Lucia; Marotta, Humberto; Queiroz Pinho, Luana; Calheiros, Debora; Crill, Patrick; Enrich-Prast, Alex

    2010-05-01

    Freshwater environments contribute on the order of 75% of the natural methane (CH4) emissions. While there are indications that tropical lakes emit 58-400 % more CH4 per area unit than similar environments in boreal and temperate biomes, direct measurements of tropical lake emissions are scarce. We measured CH4 emissions from 15 lakes in the Pantanal region of South America, one of the world's largest tropical wetland areas, during the low water period. Measured fluxes ranged from 3.9 to 74.2 mmol m-2 d-1 and the average flux from all studied lakes was 8.79 mmol m-2 d-1 (equivalent to 131.8 mg CH4 m-2 d-1). Ebullition accounted for 91 % of the flux (28-98 % on individual lakes). The use of floating diffusion chambers underlain by a submersed bubble shield in combination with regular, unshielded chambers provides a straightforward way of separating diffusive flux and ebullition. We observed diurnal cycling of emission rates and therefore 24 hour measurements are recommended compared to measurements not accounting for the full diurnal cycle. Within-lake variability of CH4 emissions may be equally or more important than between-lake variability in floodplain areas, and this study identified habitats within lakes having widely different flux rates. Future measurements with static floating chambers should be based on many individual chambers distributed in the various sub-environments shown to differ in emissions in order to account for the within-lake variability.

  7. Bayesian modeling of measurement error in predictor variables using item response theory

    NARCIS (Netherlands)

    Fox, Gerardus J.A.; Glas, Cornelis A.W.

    2000-01-01

    This paper focuses on handling measurement error in predictor variables using item response theory (IRT). Measurement error is of great important in assessment of theoretical constructs, such as intelligence or the school climate. Measurement error is modeled by treating the predictors as unobserved

  8. Measured spatial variability of beach erosion due to aeolian processes.

    NARCIS (Netherlands)

    de Vries, S.; Verheijen, A.H.; Hoonhout, B.M.; Vos, S.E.; Cohn, Nicholas; Ruggiero, P; Aagaard, T.; Deigaard, R.; Fuhrman, D.

    2017-01-01

    This paper shows the first results of measured spatial variability of beach erosion due to aeolian processes during the recently conducted SEDEX2 field experiment at Long Beach, Washington, U.S.A.. Beach erosion and sedimentation were derived using series of detailed terrestrial LIDAR measurements

  9. Complementarity in variable strength quantum non-demolition measurements

    Energy Technology Data Exchange (ETDEWEB)

    Barbieri, M; Goggin, M E; Almeida, M P; Lanyon, B P; White, A G [Centre for Quantum Computer Technology, Department of Physics, University of Queensland, QLD 4072, Brisbane (Australia)], E-mail: marco.barbieri@institutoptique.fr

    2009-09-15

    Using a linear optic quantum gate we perform a variable strength quantum non-demolition measurement, to elucidate the role of which-path knowledge in a complementarity experiment. Specifically, we demonstrate that the entanglement created by the measurement interaction prevents an exhaustive description in terms of complementary wave-like and particle-like behaviour of a single photon in an interferometer.

  10. Complementarity in variable strength quantum non-demolition measurements

    Science.gov (United States)

    Barbieri, M.; Goggin, M. E.; Almeida, M. P.; Lanyon, B. P.; White, A. G.

    2009-09-01

    Using a linear optic quantum gate we perform a variable strength quantum non-demolition measurement, to elucidate the role of which-path knowledge in a complementarity experiment. Specifically, we demonstrate that the entanglement created by the measurement interaction prevents an exhaustive description in terms of complementary wave-like and particle-like behaviour of a single photon in an interferometer.

  11. Incorporating Perceived Importance of Service Elements into Client Satisfaction Measures

    Science.gov (United States)

    Hsieh, Chang-Ming

    2012-01-01

    Objective: The purpose of this study was to assess the need for incorporating perceived importance of service elements into client satisfaction measures. Method: A secondary analysis of client satisfaction data from 112 clients of an elderly case management setting was conducted. Results: This study found that the relationship between global…

  12. PC Based Linear Variable Differential Displacement Measurement Uses Optical Technique

    Directory of Open Access Journals (Sweden)

    Tapan Kumar MAITI

    2007-07-01

    Full Text Available PC based linear variable differential displacement (LVDD measurement with optical approach has been presented. The technique is a good blending of both hardware and software and is basically an alternative method of linear variable differential transformer (LVDT. A visual basic (VB programming is used for this PC based measurement. Here the voltage output and the displacement of the reflector can be studied and stored continuously. Theoretical predictions are supported by experimental results. This technique can be used for the measurement of some non-electrical parameters e.g. force, torque and liquid level etc.

  13. Submesoscale Sea Surface Temperature Variability from UAV and Satellite Measurements

    Directory of Open Access Journals (Sweden)

    Sandra L. Castro

    2017-10-01

    Full Text Available Earlier studies of spatial variability in sea surface temperature (SST using ship-based radiometric data suggested that variability at scales smaller than 1 km is significant and affects the perceived uncertainty of satellite-derived SSTs. Here, we compare data from the Ball Experimental Sea Surface Temperature (BESST thermal infrared radiometer flown over the Arctic Ocean against coincident Moderate Resolution Imaging Spectroradiometer (MODIS measurements to assess the spatial variability of skin SSTs within 1-km pixels. By taking the standard deviation, σ, of the BESST measurements within individual MODIS pixels, we show that significant spatial variability of the skin temperature exists. The distribution of the surface variability measured by BESST shows a peak value of O(0.1 K, with 95% of the pixels showing σ < 0.45 K. Significantly, high-variability pixels are located at density fronts in the marginal ice zone, which are a primary source of submesoscale intermittency near the surface. SST wavenumber spectra indicate a spectral slope of −2, which is consistent with the presence of submesoscale processes at the ocean surface. Furthermore, the BESST wavenumber spectra not only match the energy distribution of MODIS SST spectra at the satellite-resolved wavelengths, they also span the spectral slope of −2 by ~3 decades, from wavelengths of 8 km to <0.08 km.

  14. Measuring and Predicting Tag Importance for Image Retrieval.

    Science.gov (United States)

    Li, Shangwen; Purushotham, Sanjay; Chen, Chen; Ren, Yuzhuo; Kuo, C-C Jay

    2017-12-01

    Textual data such as tags, sentence descriptions are combined with visual cues to reduce the semantic gap for image retrieval applications in today's Multimodal Image Retrieval (MIR) systems. However, all tags are treated as equally important in these systems, which may result in misalignment between visual and textual modalities during MIR training. This will further lead to degenerated retrieval performance at query time. To address this issue, we investigate the problem of tag importance prediction, where the goal is to automatically predict the tag importance and use it in image retrieval. To achieve this, we first propose a method to measure the relative importance of object and scene tags from image sentence descriptions. Using this as the ground truth, we present a tag importance prediction model to jointly exploit visual, semantic and context cues. The Structural Support Vector Machine (SSVM) formulation is adopted to ensure efficient training of the prediction model. Then, the Canonical Correlation Analysis (CCA) is employed to learn the relation between the image visual feature and tag importance to obtain robust retrieval performance. Experimental results on three real-world datasets show a significant performance improvement of the proposed MIR with Tag Importance Prediction (MIR/TIP) system over other MIR systems.

  15. Examples for the importance of radiophysical measurements in clinical phototherapy.

    Science.gov (United States)

    Schneider, Lars Alexander; Wlaschek, Meinhard; Dissemond, Joachim; Scharffetter-Kochanek, Karin

    2007-05-01

    Optimal UV therapy requires regular surveillance of the variables that influence therapeutic success. In daily practice, phototherapy equipment is often operated with an attitude of "autocontrol." This implies that thorough control measurements of the emission spectra and calibration of UV fluences are not routinely performed. For both quality control and patient safety, it is essential to regularly check whether a UV source is providing the right target spectrum with the correct dose to the skin. We have exemplarily taken three UV sources currently used in clinical practice and performed radiophysical measurements, i. e. determined emission spectra, radiation output and correctness of dose calculation. All three sources revealed either a largely inhomogeneous distribution pattern of radiation intensity, variation of radiation intensity over time or insufficient filtering of the UV lamp emission spectrum. Furthermore the dose calculation procedures had to be revised because of significant differences between the estimated and the administered UV doses. Radiophysical measurement of all UV-equipment in clinical use is a simple and effective way to improve the safety and reliability of phototherapy. Such measurements help to uncover technical flaws in radiation sources and prevent unnecessary side effects and UV exposure risks for the patient.

  16. Free testosterone: clinical utility and important analytical aspects of measurement.

    Science.gov (United States)

    Shea, Jennifer L; Wong, Pui-Yuen; Chen, Yu

    2014-01-01

    Testosterone, the most abundant androgen in men, is a steroid hormone that is synthesized predominantly by the testes. In women, minor amounts are synthesized in the ovaries. Androgen precursors are also produced and secreted from the adrenal glands in both sexes, where they undergo peripheral conversion to testosterone. Circulating concentrations are approximately 15-25 times higher in adult men compared to women. Maintenance of these levels is necessary for development and maintenance of secondary sexual characteristics, libido, growth, prevention of osteoporosis, and most importantly in men, spermatogenesis. Most testosterone circulates tightly bound to sex hormone-binding globulin (SHBG) or weakly bound to albumin. A minor amount circulates as free testosterone, and it is believed that this is the metabolically active fraction. Measurement of free testosterone is important in the diagnosis of many diseases, most importantly disorders of androgen deficiency in men (i.e., hypogonadism) and androgen excess in women (i.e., polycystic ovary syndrome and hirsutism). Many methodologies are available for free testosterone measurement including the reference methods (equilibrium dialysis and ultrafiltration), analog immunoassay, and calculated free testosterone based on measurement of total testosterone, SHBG, and albumin. Moreover, measurement of bioavailable testosterone, a combination of albumin-bound and free testosterone, also has clinical utility and can be measured by selective protein precipitation or calculation. In this review, the advantages and limitations of each of these methods will be discussed in the context of clinical utility and implementation into a routine hospital laboratory. Furthermore, up and coming methodologies for free testosterone measurement, including liquid chromatography-tandem mass spectrometry, will also be discussed.

  17. Measuring Quasar Variability with Pan-STARRS1 and SDSS

    Science.gov (United States)

    Morganson, E.; Burgett, W. S.; Chambers, K. C.; Green, P. J.; Kaiser, N.; Magnier, E. A.; Marshall, P. J.; Morgan, J. S.; Price, P. A.; Rix, H.-W.; Schlafly, E. F.; Tonry, J. L.; Walter, F.

    2014-04-01

    We measure quasar variability using the Panoramic Survey Telescope and Rapid Response System 1 Survey (Pan-STARRS1 or PS1) and the Sloan Digital Sky Survey (SDSS) and establish a method of selecting quasars via their variability in 104 deg2 surveys. We use 105 spectroscopically confirmed quasars that have been well measured in both PS1 and SDSS and take advantage of the decadal timescales that separate SDSS measurements and PS1 measurements. A power law model fits the data well over the entire time range tested, 0.01-10 yr. Variability in the current PS1-SDSS data set can efficiently distinguish between quasars and nonvarying objects. It improves the purity of a griz quasar color cut from 4.1% to 48% while maintaining 67% completeness. Variability will be very effective at finding quasars in data sets with no u band and in redshift ranges where exclusively photometric selection is not efficient. We show that quasars' rest-frame ensemble variability, measured as a root mean squared in Δ magnitudes, is consistent with V(z, L, t) = A 0(1 + z)0.37(L/L 0)-0.16(t/1 yr)0.246, where L 0 = 1046 erg s-1 and A 0 = 0.190, 0.162, 0.147, or 0.141 in the g P1, r P1, i P1, or z P1filter, respectively. We also fit across all four filters and obtain median variability as a function of z, L, and λ as V(z, L, λ, t) = 0.079(1 + z)0.15(L/L 0)-0.2(λ/1000 nm)-0.44(t/1 yr)0.246.

  18. Screening of variable importance for optimizing electrodialytic remediation of heavy metals from polluted harbour sediments

    DEFF Research Database (Denmark)

    Pedersen, Kristine B.; Lejon, Tore; Ottosen, Lisbeth M.

    2015-01-01

    Using multivariate design and modelling, the optimal conditions for electrodialytic remediation (EDR) of heavy metals were determined for polluted harbour sediments from Hammerfest harbour located in the geographic Arctic region of Norway. The comparative importance of the variables, current...... density, remediation time, light/no light, the liquid-solid ratio and stirring rate of the sediment suspension, was determined in 15 laboratory-scale EDR experiments by projection to latent structures (PLS). The relation between the X matrix (experimental variables) and the Y matrix (removal efficiencies...

  19. Importance of variable time-step algorithms in spatial kinetics calculations

    Energy Technology Data Exchange (ETDEWEB)

    Aviles, B.N.

    1994-12-31

    The use of spatial kinetics codes in conjunction with advanced thermal-hydraulics codes is becoming more widespread as better methods and faster computers appear. The integrated code packages are being used for routine nuclear power plant design and analysis, including simulations with instrumentation and control systems initiating system perturbations such as rod motion and scrams. As a result, it is important to include a robust variable time-step algorithm that can accurately and efficiently follow widely varying plant neutronic behavior. This paper describes the variable time-step algorithm in SPANDEX and compares the automatic time-step scheme with a more traditional fixed time-step scheme.

  20. Determination of continuous variable entanglement by purity measurements.

    Science.gov (United States)

    Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

    2004-02-27

    We classify the entanglement of two-mode Gaussian states according to their degree of total and partial mixedness. We derive exact bounds that determine maximally and minimally entangled states for fixed global and marginal purities. This characterization allows for an experimentally reliable estimate of continuous variable entanglement based on measurements of purity.

  1. Molecular variability and genetic structure of Chrysodeixis includens (Lepidoptera: Noctuidae), an important soybean defoliator in Brazil

    OpenAIRE

    Janine Palma; Kevin Maebe; Jerson Vanderlei Carús Guedes; Guy Smagghe

    2015-01-01

    This study provides the first genetic characterization of the soybean looper, Chrysodeixis includens (Walker, 1857), an important defoliating pest species of soybean crops in Brazil. Population genetic variability and the genetic structure of C. includens populations were evaluated by using ISSR markers with samples from the major soybean producing regions in Brazil in the growing seasons 2011/2012. Seven different primers were applied for population characterization of the molecular variabil...

  2. Assessing the Importance of Intraspecific Variability in Dung Beetle Functional Traits.

    Directory of Open Access Journals (Sweden)

    Hannah M Griffiths

    Full Text Available Functional diversity indices are used to facilitate a mechanistic understanding of many theoretical and applied questions in current ecological research. The use of mean trait values in functional indices assumes that traits are robust, in that greater variability exists between than within species. While the assertion of robust traits has been explored in plants, there exists little information on the source and extent of variability in the functional traits of higher trophic level organisms. Here we investigated variability in two functionally relevant dung beetle traits, measured from individuals collected from three primary forest sites containing distinct beetle communities: body mass and back leg length. In doing so we too addressed the following questions: (i what is the contribution of intra vs. interspecific differences in trait values; (ii what sample size is needed to provide representative species mean trait values; and (iii what impact does omission of intraspecific trait information have on the calculation of functional diversity (FD indices from naturally assembled communities? At the population level, interspecific differences explained the majority of variability in measured traits (between 94% and 96%. In accordance with this, the error associated with calculating FD without inclusion of intraspecific variability was low, less than 20% in all cases. This suggests that complete sampling to capture intraspecific variance in traits is not necessary even when investigating the FD of small and/or naturally formed communities. To gain an accurate estimation of species mean trait values we encourage the measurement of 30-60 individuals and, where possible, these should be taken from specimens collected from the site of study.

  3. Long-term variability of importance of brain regions in evolving epileptic brain networks

    Science.gov (United States)

    Geier, Christian; Lehnertz, Klaus

    2017-04-01

    We investigate the temporal and spatial variability of the importance of brain regions in evolving epileptic brain networks. We construct these networks from multiday, multichannel electroencephalographic data recorded from 17 epilepsy patients and use centrality indices to assess the importance of brain regions. Time-resolved indications of highest importance fluctuate over time to a greater or lesser extent, however, with some periodic temporal structure that can mostly be attributed to phenomena unrelated to the disease. In contrast, relevant aspects of the epileptic process contribute only marginally. Indications of highest importance also exhibit pronounced alternations between various brain regions that are of relevance for studies aiming at an improved understanding of the epileptic process with graph-theoretical approaches. Nonetheless, these findings may guide new developments for individualized diagnosis, treatment, and control.

  4. Long-term variability of importance of brain regions in evolving epileptic brain networks.

    Science.gov (United States)

    Geier, Christian; Lehnertz, Klaus

    2017-04-01

    We investigate the temporal and spatial variability of the importance of brain regions in evolving epileptic brain networks. We construct these networks from multiday, multichannel electroencephalographic data recorded from 17 epilepsy patients and use centrality indices to assess the importance of brain regions. Time-resolved indications of highest importance fluctuate over time to a greater or lesser extent, however, with some periodic temporal structure that can mostly be attributed to phenomena unrelated to the disease. In contrast, relevant aspects of the epileptic process contribute only marginally. Indications of highest importance also exhibit pronounced alternations between various brain regions that are of relevance for studies aiming at an improved understanding of the epileptic process with graph-theoretical approaches. Nonetheless, these findings may guide new developments for individualized diagnosis, treatment, and control.

  5. Intercomparison of measurements of distribution coefficient. Investigation of factors affecting variability of measured values

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Tomoyuki; Takebe, Shinichi; Kimura, Hideo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    1997-10-01

    The distribution coefficient(Kd), which is defined as partitioning of solute between a solid and liquid phases, is used for various models which describe the migration behavior of nuclides in the environment. Therefore it is a very important parameter for safety assessment of nuclear facilities. Aiming at the recommendation of standard methodologies for measurement and application of Kd, we have discussed a procedure of standardization in `WG on Parameters for Safety Assessment` of `Technical Committee on Behavior of Environmental Radioactivity` which belongs to `Research Committee on Environmental Radioactivity` organized by Japan Atomic Energy Research Institute. As a first step for recommendation of a standard methodology for measurement, intercomparisons on measurement of Kd for radionuclides ({sup 60}Co, {sup 137}Cs, {sup 85}Sr and {sup 54}Mn) were carried out by four groups to evaluate the cause of variability in measured Kds. As a result of five different experiments under various conditions, it was found that the difference of chemical property of radionuclide solution, form of vessels and method of shaking have strong influence on the measured values of Kd. (author)

  6. Are changes in the mean or variability of climate signals more important for long-term stochastic growth rate?

    Directory of Open Access Journals (Sweden)

    Bernardo García-Carreras

    Full Text Available Population dynamics are affected by changes in both the mean and standard deviation of climate, e.g., changes in average temperature are likely to affect populations, but so are changes in the strength of year-to-year temperature variability. The impacts of increases in average temperature are extensively researched, while the impacts of changes in climate variability are less studied. Is the greater attention given to changes in mean environment justified? To help answer this question we developed a simple population model, explicitly linked to an environmental process. We used the model to compare the sensitivities of a population's long-term stochastic growth rate, a measure of fitness, to changes in the mean and standard deviation of the environment. Results are interpreted in light of a comparative analysis of the relative magnitudes of change in means and standard deviations of biologically relevant climate variables in the United States. Results show that changes in the variability of the environment can be more important for many populations. Changes in mean conditions are likely to have a greater impact than changes in variability on populations far from their ideal environment, for example, populations near species range boundaries and potentially of conservation concern. Populations near range centres and close to their ideal environment are more likely to be affected by changes in variability. Among pest and insect disease vectors, as well as species of commercial value, populations likely to be of greatest economic and public health significance are those near species range centers, living in a near-ideal environment for the species. Observed changes in the variability of climate variables may benefit these populations.

  7. Assessing heart rate variability through wavelet-based statistical measures.

    Science.gov (United States)

    Wachowiak, Mark P; Hay, Dean C; Johnson, Michel J

    2016-10-01

    Because of its utility in the investigation and diagnosis of clinical abnormalities, heart rate variability (HRV) has been quantified with both time and frequency analysis tools. Recently, time-frequency methods, especially wavelet transforms, have been applied to HRV. In the current study, a complementary computational approach is proposed wherein continuous wavelet transforms are applied directly to ECG signals to quantify time-varying frequency changes in the lower bands. Such variations are compared for resting and lower body negative pressure (LBNP) conditions using statistical and information-theoretic measures, and compared with standard HRV metrics. The latter confirm the expected lower variability in the LBNP condition due to sympathetic nerve activity (e.g. RMSSD: p=0.023; SDSD: p=0.023; LF/HF: p=0.018). Conversely, using the standard Morlet wavelet and a new transform based on windowed complex sinusoids, wavelet analysis of the ECG within the observed range of heart rate (0.5-1.25Hz) exhibits significantly higher variability, as measured by frequency band roughness (Morlet CWT: p=0.041), entropy (Morlet CWT: p=0.001), and approximate entropy (Morlet CWT: p=0.004). Consequently, this paper proposes that, when used with well-established HRV approaches, time-frequency analysis of ECG can provide additional insights into the complex phenomenon of heart rate variability. Copyright © 2016. Published by Elsevier Ltd.

  8. Estimation of road profile variability from measured vehicle responses

    Science.gov (United States)

    Fauriat, W.; Mattrand, C.; Gayton, N.; Beakou, A.; Cembrzynski, T.

    2016-05-01

    When assessing the statistical variability of fatigue loads acting throughout the life of a vehicle, the question of the variability of road roughness naturally arises, as both quantities are strongly related. For car manufacturers, gathering information on the environment in which vehicles evolve is a long and costly but necessary process to adapt their products to durability requirements. In the present paper, a data processing algorithm is proposed in order to estimate the road profiles covered by a given vehicle, from the dynamic responses measured on this vehicle. The algorithm based on Kalman filtering theory aims at solving a so-called inverse problem, in a stochastic framework. It is validated using experimental data obtained from simulations and real measurements. The proposed method is subsequently applied to extract valuable statistical information on road roughness from an existing load characterisation campaign carried out by Renault within one of its markets.

  9. Variability of Measured Runoff and Soil Loss from Field Plots

    Directory of Open Access Journals (Sweden)

    F. Asadzadeh

    2016-02-01

    Full Text Available Introduction: Field plots are widely used in studies related to the measurements of soil loss and modeling of erosion processes. Research efforts are needed to investigate factors affecting the data quality of plots. Spatial scale or size of plots is one of these factors which directly affects measuring runoff and soil loss by means of field plots. The effect of plot size on measured runoff or soil loss from natural plots is known as plot scale effect. On the other hand, variability of runoff and sediment yield from replicated filed plots is a main source of uncertainty in measurement of erosion from plots which should be considered in plot data interpretation processes. Therefore, there is a demand for knowledge of soil erosion processes occurring in plots of different sizes and of factors that determine natural variability, as a basis for obtaining soil loss data of good quality. This study was carried out to investigate the combined effects of these two factors by measurement of runoff and soil loss from replicated plots with different sizes. Materials and Methods: In order to evaluate the variability of runoff and soil loss data seven plots, differing in width and length, were constructed in a uniform slope of 9% at three replicates at Koohin Research Station in Qazvin province. The plots were ploughed up to down slope in September 2011. Each plot was isolated using soil beds with a height of 30 cm, to direct generated surface runoff to the lower part of the plots. Runoff collecting systems composed of gutters, pipes and tankswere installed at the end of each plot. During the two-year study period of 2011-2012, plots were maintained in bare conditions and runoff and soil loss were measured for each single event. Precipitation amounts and characteristics were directly measured by an automatic recording tipping-bucket rain gauge located about 200 m from the experimental plots. The entire runoff volume including eroded sediment was measured on

  10. Importance of measuring lactate levels in children with sepsis.

    Science.gov (United States)

    Anil, Nisha

    2017-10-10

    Sepsis is a major public health problem as well as one of the leading causes of preventable death in children because of failure to recognise the early signs and symptoms and to resuscitate rapidly. Blood lactate levels are used to assess the severity of sepsis and the effectiveness of resuscitation. Lactate levels are easily obtainable and should be checked in all patients admitted with suspected sepsis within six hours of presentation. The test should be repeated four and eight-hours post-diagnosis of sepsis. For the diagnosis of sepsis, patients' clinical symptoms, along with the combined analysis of partial pressure of oxygen, carbon dioxide and lactate levels, should be used. A multitude of factors can cause elevated lactate levels and so clinicians should use elevated levels cautiously by considering all other aetiologies. This article, which focuses on practice in Australia but makes reference to the UK, discusses the importance of measuring lactate levels in sepsis, the pathophysiology of lactate production, causes of elevated lactate levels, lactate measurement, nursing management of patients with elevated lactate levels, limitations of using lactate as a biomarker for diagnosing sepsis and implications for practice. ©2012 RCN Publishing Company Ltd. All rights reserved. Not to be copied, transmitted or recorded in any way, in whole or part, without prior permission of the publishers.

  11. Sources of variability in metabolite measurements from urinary samples.

    Directory of Open Access Journals (Sweden)

    Qian Xiao

    Full Text Available The application of metabolomics in epidemiological studies would potentially allow researchers to identify biomarkers associated with exposures and diseases. However, within-individual variability of metabolite levels caused by temporal variation of metabolites, together with technical variability introduced by laboratory procedures, may reduce the study power to detect such associations. We assessed the sources of variability of metabolites from urine samples and the implications for designing epidemiologic studies.We measured 539 metabolites in urine samples from the Navy Colon Adenoma Study using liquid chromatography-mass spectrometry (LC-MS and gas chromatography-mass spectroscopy (GC-MS. The study collected 2-3 samples per person from 17 male subjects (age 38-70 over 2-10 days. We estimated between-individual, within-individual, and technical variability and calculated expected study power with a specific focus on large case-control and nested case-control studies.Overall technical reliability was high (median intraclass correlation = 0.92, and for 72% of the metabolites, the majority of total variance can be attributed to between-individual variability. Age, gender and body mass index explained only a small proportion of the total metabolite variability. For a relative risk (comparing upper and lower quartiles of "usual" levels of 1.5, we estimated that a study with 500, 1,000, and 5,000 individuals could detect 1.0%, 4.5% and 75% of the metabolite associations.The use of metabolomics in urine samples from epidemiological studies would require large sample sizes to detect associations with moderate effect sizes.

  12. Performance Measure as Feedback Variable in Image Processing

    Directory of Open Access Journals (Sweden)

    Ristić Danijela

    2006-01-01

    Full Text Available This paper extends the view of image processing performance measure presenting the use of this measure as an actual value in a feedback structure. The idea behind is that the control loop, which is built in that way, drives the actual feedback value to a given set point. Since the performance measure depends explicitly on the application, the inclusion of feedback structures and choice of appropriate feedback variables are presented on example of optical character recognition in industrial application. Metrics for quantification of performance at different image processing levels are discussed. The issues that those metrics should address from both image processing and control point of view are considered. The performance measures of individual processing algorithms that form a character recognition system are determined with respect to the overall system performance.

  13. Review of energy system flexibility measures to enable high levels of variable renewable electricity

    OpenAIRE

    Peter D. Lund; Lindgren, Juuso; Mikkola, Jani; Salpakari, Jyri

    2015-01-01

    The paper reviews different approaches, technologies, and strategies to manage large-scale schemes of variable renewable electricity such as solar and wind power. We consider both supply and demand side measures. In addition to presenting energy system flexibility measures, their importance to renewable electricity is discussed. The flexibility measures available range from traditional ones such as grid extension or pumped hydro storage to more advanced strategies such as demand side manageme...

  14. Time-dependent prediction and evaluation of variable importance using superlearning in high-dimensional clinical data.

    Science.gov (United States)

    Hubbard, Alan; Munoz, Ivan Diaz; Decker, Anna; Holcomb, John B; Schreiber, Martin A; Bulger, Eileen M; Brasel, Karen J; Fox, Erin E; del Junco, Deborah J; Wade, Charles E; Rahbar, Mohammad H; Cotton, Bryan A; Phelan, Herb A; Myers, John G; Alarcon, Louis H; Muskat, Peter; Cohen, Mitchell J

    2013-07-01

    Prediction of outcome after injury is fraught with uncertainty and statistically beset by misspecified models. Single-time point regression only gives prediction and inference at one time, of dubious value for continuous prediction of ongoing bleeding. New statistical machine learning techniques such as SuperLearner (SL) exist to make superior prediction at iterative time points while evaluating the changing relative importance of each measured variable on an outcome. This then can provide continuously changing prediction of outcome and evaluation of which clinical variables likely drive a particular outcome. PROMMTT data were evaluated using both naive (standard stepwise logistic regression) and SL techniques to develop a time-dependent prediction of future mortality within discrete time intervals. We avoided both underfitting and overfitting using cross validation to select an optimal combination of predictors among candidate predictors/machine learning algorithms. SL was also used to produce interval-specific robust measures of variable importance measures (VIM resulting in an ordered list of variables, by time point) that have the strongest impact on future mortality. Nine hundred eighty patients had complete clinical and outcome data and were included in the analysis. The prediction of ongoing transfusion with SL was superior to the naive approach for all time intervals (correlations of cross-validated predictions with the outcome were 0.819, 0.789, 0.792 for time intervals 30-90, 90-180, 180-360, >360 minutes). The estimated VIM of mortality also changed significantly at each time point. The SL technique for prediction of outcome from a complex dynamic multivariate data set is superior at each time interval to standard models. In addition, the SL VIM at each time point provides insight into the time-specific drivers of future outcome, patient trajectory, and targets for clinical intervention. Thus, this automated approach mimics clinical practice, changing

  15. The importance of pre-measurements of wellbeing and achievement for students' current wellbeing

    OpenAIRE

    Karen Van Petegem; Bert Creemers; Antonia Aelterman; Yves Rosseel

    2008-01-01

    Educational effectiveness research focuses not only on cognitive output but also on affective student outcomes. Student wellbeing has to be addressed as an important output variable of the educational process. The focus in this study is on student wellbeing at the end of Grade 10 and its relationship to current achievement, and pre-measurements of student wellbeing and achievement. Student characteristics and motives for attending school are taken into account. Moreover, within classroom envi...

  16. Determining relative importance of variables in developing and validating predictive models

    Directory of Open Access Journals (Sweden)

    Atenafu Eshetu G

    2009-09-01

    Full Text Available Abstract Background Multiple regression models are used in a wide range of scientific disciplines and automated model selection procedures are frequently used to identify independent predictors. However, determination of relative importance of potential predictors and validating the fitted models for their stability, predictive accuracy and generalizability are often overlooked or not done thoroughly. Methods Using a case study aimed at predicting children with acute lymphoblastic leukemia (ALL who are at low risk of Tumor Lysis Syndrome (TLS, we propose and compare two strategies, bootstrapping and random split of data, for ordering potential predictors according to their relative importance with respect to model stability and generalizability. We also propose an approach based on relative increase in percentage of explained variation and area under the Receiver Operating Characteristic (ROC curve for developing models where variables from our ordered list enter the model according to their importance. An additional data set aimed at identifying predictors of prostate cancer penetration is also used for illustrative purposes. Results Age is chosen to be the most important predictor of TLS. It is selected 100% of the time using the bootstrapping approach. Using the random split method, it is selected 99% of the time in the training data and is significant (at 5% level 98% of the time in the validation data set. This indicates that age is a stable predictor of TLS with good generalizability. The second most important variable is white blood cell count (WBC. Our methods also identified an important predictor of TLS that was otherwise omitted if relying on any of the automated model selection procedures alone. A group at low risk of TLS consists of children younger than 10 years of age, without T-cell immunophenotype, whose baseline WBC is 9/L and palpable spleen is Conclusion Our model selection procedures based on bootstrap re-sampling and

  17. Gait assessment system based on novel gait variability measures.

    Science.gov (United States)

    Wang, Xingchen; Ristic-Durrant, Danijela; Spranger, Matthias; Graser, Axel

    2017-07-01

    In this paper, a novel gait assessment system based on measures of gait variability reflected through the variability of shapes of gait cycles trajectories is proposed. The presented gait assessment system is based on SVM (support vector machine) classifier and on gait variability-based features calculated from the hip and knee joint angle trajectories recorded using wearable IMUs during walking trials. A system classifier was trained to distinguish healthy gait patterns from the pathological ones. The features were extracted by calculating the distances between the joint trajectories of the individual gait cycles using 4 different distance functions. As result, the system is able to provide a Gait Variability Index (GVI), which is a numeric value that can be used as an indicator of a degree to which a pathological gait pattern is close to a healthy gait pattern. The system and GVI were tested in three experiments, involving subjects suffering from gait disorders caused by different neurological diseases. The results demonstrated that the proposed gait assessment system would be suitable for supporting clinicians in the evaluation of gait performances during the gait rehabilitation procedures.

  18. Treatment of hypertension based on measurement of blood pressure variability: lessons from animal studies.

    Science.gov (United States)

    Su, Ding-Feng

    2006-09-01

    Blood pressure variability, a quantitative index for the spontaneous variation in blood pressure, has been proposed as a risk factor for end-organ damage and to determine the efficacy of hypertension treatment. Animal studies indicate that blood pressure variability is as important as blood pressure level in determining end-organ damage, and that high blood pressure variability is associated with end-organ damage, including myocardial lesions, aortic hypertrophy, vascular remodeling and renal damage. Although the organ damage induced by high blood pressure variability was similar to that induced by hypertension, comparative studies in sinoaortic-denervated and spontaneously hypertensive rats revealed that aortic hypertrophy is a sensitive index of high blood pressure variability, and left ventricular hypertrophy is a sensitive index of high blood pressure level. The possible mechanisms for high blood pressure variability-induced end-organ damage include: direct endothelial lesions, renin-angiotensin system activation, inflammation initiation and cardiomyocyte apoptosis augmentation. Blood pressure variability reduction contributes importantly to the organ-protective effect of some antihypertensive drugs. Although animal studies suggest some advantages in blood pressure variability measurements, clinical trials are necessary before the widespread use of blood pressure variability as a predictor of hypertensive organ damage and a new strategy for the treatment of hypertension.

  19. Sources of Variability in Musculo-Articular Stiffness Measurement

    Science.gov (United States)

    Ditroilo, Massimiliano; Watsford, Mark; Murphy, Aron; De Vito, Giuseppe

    2013-01-01

    The assessment of musculo-articular stiffness (MAS) with the free-oscillation technique is a popular method with a variety of applications. This study examined the sources of variability (load applied and frequency of oscillation) when MAS is assessed. Over two testing occasions, 14 healthy men (27.7±5.2 yr, 1.82±0.04 m, 79.5±8.4 kg) were measured for isometric maximum voluntary contraction and MAS of the knee flexors using submaximal loads relative to the individual's maximum voluntary contraction (MAS%MVC) and a single absolute load (MASABS). As assessment load increased, MAS%MVC (coefficient of variation (CV)  =  8.1–12.1%; standard error of measurement (SEM)  =  51.6–98.8 Nm−1) and frequency (CV  =  4.8–7.0%; SEM  =  0.060–0.075 s−1) variability increased consequently. Further, similar levels of variability arising from load (CV  =  6.7%) and frequency (CV  =  4.8–7.0%) contributed to the overall MAS%MVC variability. The single absolute load condition yielded better reliability scores for MASABS (CV  =  6.5%; SEM  =  40.2 Nm−1) and frequency (CV  =  3.3%; SEM  =  0.039 s−1). Low and constant loads for MAS assessment, which are particularly relevant in the clinical setting, exhibited superior reliability compared to higher loads expressed as a percentage of maximum voluntary contraction, which are more suitable for sporting situations. Appropriate sample size and minimum detectable change can therefore be determined when prospective studies are carried out. PMID:23667662

  20. Application of a Deep Neural Network to Metabolomics Studies and Its Performance in Determining Important Variables.

    Science.gov (United States)

    Date, Yasuhiro; Kikuchi, Jun

    2018-02-06

    Deep neural networks (DNNs), which are kinds of the machine learning approaches, are powerful tools for analyzing big sets of data derived from biological and environmental systems. However, DNNs are not applicable to metabolomics studies because they have difficulty in identifying contribution factors, e.g., biomarkers, in constructed classification and regression models. In this paper, we describe an improved DNN-based analytical approach that incorporates an importance estimation for each variable using a mean decrease accuracy (MDA) calculation, which is based on a permutation algorithm; this approach is called DNN-MDA. The performance of the DNN-MDA approach was evaluated using a data set of metabolic profiles derived from yellowfin goby that lived in various rivers throughout Japan. Its performance was compared with that of conventional multivariate and machine learning methods, and the DNN-MDA approach was found to have the best classification accuracy (97.8%) among the examined methods. In addition to this, the DNN-MDA approach facilitated the identification of important variables such as trimethylamine N-oxide, inosinic acid, and glycine, which were characteristic metabolites that contributed to the discrimination of the geographical differences between fish caught in the Kanto region and those caught in other regions. As a result, the DNN-MDA approach is a useful and powerful tool for determining the geographical origins of specimens and identifying their biomarkers in metabolomics studies that are conducted in biological and environmental systems.

  1. FIRE: an SPSS program for variable selection in multiple linear regression analysis via the relative importance of predictors

    National Research Council Canada - National Science Library

    Lorenzo-Seva, Urbano; Ferrando, Pere J

    2011-01-01

    We provide an SPSS program that implements currently recommended techniques and recent developments for selecting variables in multiple linear regression analysis via the relative importance of predictors...

  2. A State-Based Sensitivity Analysis for Distinguishing the Global Importance of Predictor Variables in Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Ehsan Ardjmand

    2016-01-01

    Full Text Available Artificial neural networks (ANNs are powerful empirical approaches used to model databases with a high degree of accuracy. Despite their recognition as universal approximators, many practitioners are skeptical about adopting their routine usage due to lack of model transparency. To improve the clarity of model prediction and correct the apparent lack of comprehension, researchers have utilized a variety of methodologies to extract the underlying variable relationships within ANNs, such as sensitivity analysis (SA. The theoretical basis of local SA (that predictors are independent and inputs other than variable of interest remain “fixed” at predefined values is challenged in global SA, where, in addition to altering the attribute of interest, the remaining predictors are varied concurrently across their respective ranges. Here, a regression-based global methodology, state-based sensitivity analysis (SBSA, is proposed for measuring the importance of predictor variables upon a modeled response within ANNs. SBSA was applied to network models of a synthetic database having a defined structure and exhibiting multicollinearity. SBSA achieved the most accurate portrayal of predictor-response relationships (compared to local SA and Connected Weights Analysis, closely approximating the actual variability of the modeled system. From this, it is anticipated that skepticisms concerning the delineation of predictor influences and their uncertainty domains upon a modeled output within ANNs will be curtailed.

  3. Quantifying variability in the measurement of control in intermittent exotropia.

    Science.gov (United States)

    Hatt, Sarah R; Leske, David A; Liebermann, Laura; Holmes, Jonathan M

    2015-02-01

    To evaluate the performance of a series of summary measures of control and to assess reliability in quantifying exodeviation control in intermittent exotropia. A large, simulated dataset of control scores for 10,000 hypothetical patients with intermittent exotropia was created using Monte Carlo simulations. These data were based on children with intermittent exotropia in whom control was assessed twice during one clinical examination, using the office control score (0-5). Each simulated patient had a baseline and 11 subsequent control scores. The repeatability of a series of summary measures of control (the mean of 2 vs the mean of 3 up to the mean of 6), was calculated using 95% limits of agreement (LOA). A total of 322 examinations in 152 patients were used to provide representative distributions of control scores. From the resultant Monte Carlo simulations, the 95% LOAs were 2.60 for 1 distance control score measure, 1.76 for the average of 3, and 1.28 for the average of 6. Therefore using the average of 3 scores, a change of variability, whereas a change of >1.76 would suggest a real change in control. The large dataset of simulated control scores allowed us to assess the variability of specific summary measures of control. We recommend the average of 3 scores (a triple control score) as a new standard for assessing control, providing improved reliability over a single measure, while remaining implementable in clinical practice. Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  4. Individual variability in clinical effect and tolerability of opioid analgesics - Importance of drug interactions and pharmacogenetics.

    Science.gov (United States)

    Solhaug, Vigdis; Molden, Espen

    2017-10-17

    As pain is often a comorbid condition, many patients use opioid analgesics in combination with several other drugs. This implies a generally increased risk of drug interactions, which along with inherent pharmacogenetic variability and other factors may cause differences in therapeutic response of opioids. To provide an overview of interactions and pharmacogenetic variability of relevance for individual differences in effect and tolerability of opioid analgesics, which physicians and other healthcare professionals should be aware of in clinical practice. The article was based on unsystematic searches in PubMed to identify literature highlighting the clinical impact of drug interactions and pharmacogenetics as sources of variable response of opioid analgesics. Cytochrome P450 (CYP)-mediated metabolism is an important process for both clinically relevant interactions and pharmacogenetic variability of several opioids. Concomitant use of CYP inhibitors (e.g. paroxetine, fluoxetine and bupropion) or inducers (e.g. carbamazepine, phenobarbital and phenytoin) could counteract the clinical effect or trigger side effects of analgesics in the same manner as genetically determined differences in CYP2D6-mediated metabolism of many opioids. Moreover, combination treatment with drugs that inhibit or induce P-glycoprotein (ABCB1), a blood-brain barrier efflux transporter, may alter the amount ('dose') of opioids distributed to the brain. At the pharmacodynamic level, it is crucial to be aware of the potential risk of interaction causing serotonergic syndrome when combining opioids and serotonergic drugs, in particular antidepressants inhibiting serotonin reuptake (SSRIs and SNRIs). Regarding pharmacogenetics at the receptor level of pain treatment, the knowledge is currently scarce, but an allelic variant of the μ1 opioid receptor (OPRM1) gene has been associated with higher dosage requirement to achieve analgesia. Drug interactions and pharmacogenetic differences may lead to

  5. [Diabetes mellitus: how important is it to measure the quality of life?].

    Science.gov (United States)

    Kulzer, B

    2006-12-01

    Maintaining the quality of life (QoL) of diabetics is a decisive outcome variable in the treatment of diabetes. It should be used as an important indicator of quality in assessing efficacy and effectiveness of therapeutic measures. QoL of diabetics is reduced compared with non-diabetics. Diabetics with impaired QoL more frequently suffer from subclinical or clinical depression, which clearly impairs the short-term and chronic prognosis of the disease. The WHO-5 questionnaire has proven valuable for measuring QoL and in screening for depression. It is a simple and valid method of assessment which is recommended in international and national guidelines.

  6. [Comparison of heart rate variability measurements between ballistocardiogram and electrocardiography].

    Science.gov (United States)

    Wang, Kun; Zhu, Tiangang; Zhang, Xianwen; Yu, Chao; Cao, Xinrong; Tang, Jintian; Wan, Zheng

    2015-05-01

    To compare the heart rate variability (HRV) measurements between ballistocardiogram (BCG) and electrocardiography (ECG). The signals of BCG and ECG of 21 patients were collected synchronously. JJ intervals of BCG and RR intervals of ECG were used to calculate the cardiac periods. The parameters of HRV analysis were calculated in time domain analysis, frequency domain analysis and nonlinear analysis. The results derived from BCG and ECG were compared. The parameters of HRV analysis calculated from BCG and ECG had high similarity. The correlation coefficients of SDNN, TP, LF, HF and SD2 between the BCG and ECG methods were high (r = 1). The correlation coefficients of rMSSD and SD2 were 0.99 and of PNN50 and LF/HF were 0.98 between the two methods. HRV analysis results derived from the two methods were similar (P > 0.05). HRV could also be measured reliably by calculating the JJ interval from BCG.

  7. The Importance of Freshwater to Spatial Variability of Aragonite Saturation State in the Gulf of Alaska

    Science.gov (United States)

    Siedlecki, Samantha A.; Pilcher, Darren J.; Hermann, Albert J.; Coyle, Ken; Mathis, Jeremy

    2017-11-01

    High-latitude and subpolar regions like the Gulf of Alaska (GOA) are more vulnerable than equatorial regions to rising carbon dioxide (CO2) levels, in part due to local processes that amplify the global signal. Recent field observations have shown that the shelf of the GOA is currently experiencing seasonal corrosive events (carbonate mineral saturation states Ω, Ω < 1), including suppressed Ω in response to ocean acidification as well as local processes like increased low-alkalinity glacial meltwater discharge. While the glacial discharge mainly influences the inner shelf, on the outer shelf, upwelling brings corrosive waters from the deep GOA. In this work, we develop a high-resolution model for carbon dynamics in the GOA, identify regions of high variability of Ω, and test the sensitivity of those regions to changes in the chemistry of glacial meltwater discharge. Results indicate the importance of this climatically sensitive and relatively unconstrained regional freshwater forcing for Ω variability in the nearshore. The increase was nearly linear at 0.002 Ω per 100 µmol/kg increase in alkalinity in the freshwater runoff. We find that the local winds, biological processes, and freshwater forcing all contribute to the spatial distribution of Ω and identify which of these three is highly correlated to the variability in Ω. Given that the timing and magnitude of these processes will likely change during the next few decades, it is critical to elucidate the effect of local processes on the background ocean acidification signal using robust models, such as the one described here.

  8. Molecular variability and genetic structure of Chrysodeixis includens (Lepidoptera: Noctuidae), an important soybean defoliator in Brazil.

    Science.gov (United States)

    Palma, Janine; Maebe, Kevin; Guedes, Jerson Vanderlei Carús; Smagghe, Guy

    2015-01-01

    This study provides the first genetic characterization of the soybean looper, Chrysodeixis includens (Walker, 1857), an important defoliating pest species of soybean crops in Brazil. Population genetic variability and the genetic structure of C. includens populations were evaluated by using ISSR markers with samples from the major soybean producing regions in Brazil in the growing seasons 2011/2012. Seven different primers were applied for population characterization of the molecular variability and genetic structure of 8 soybean looper populations from 8 states of Brazil. The seven ISSR loci generated 247 bands in 246 individuals of C. includens sampled. The expected heterozygosity (HE) in the populations varied between 0.093 and 0.106, while the overall HE was 0.099, indicating low genetic diversity. The analysis of molecular variance indicated that 98% of the variability was expressed among individuals within populations (FST = 0.021, p = 0.001). The low level of polymorphism over all populations, the high levels of gene flow, and the low genetic structure are indicatives of the exchange of genetic information between the different sampled regions. Population structuring suggests the presence of two major groups which do not correlate with their geographic sampling location in Brazil. These results may indicate recent recolonization of C. includens in Brazil or migration patterns following source-sink dynamics. Furthermore, the presence of two groups within C. includens suggests that a study on development of resistance or any other genetic-based trait needs to be evaluated on both groups, and pest management in soybean fields should be aware that differences may come to the control strategies they use.

  9. Molecular variability and genetic structure of Chrysodeixis includens (Lepidoptera: Noctuidae, an important soybean defoliator in Brazil.

    Directory of Open Access Journals (Sweden)

    Janine Palma

    Full Text Available This study provides the first genetic characterization of the soybean looper, Chrysodeixis includens (Walker, 1857, an important defoliating pest species of soybean crops in Brazil. Population genetic variability and the genetic structure of C. includens populations were evaluated by using ISSR markers with samples from the major soybean producing regions in Brazil in the growing seasons 2011/2012. Seven different primers were applied for population characterization of the molecular variability and genetic structure of 8 soybean looper populations from 8 states of Brazil. The seven ISSR loci generated 247 bands in 246 individuals of C. includens sampled. The expected heterozygosity (HE in the populations varied between 0.093 and 0.106, while the overall HE was 0.099, indicating low genetic diversity. The analysis of molecular variance indicated that 98% of the variability was expressed among individuals within populations (FST = 0.021, p = 0.001. The low level of polymorphism over all populations, the high levels of gene flow, and the low genetic structure are indicatives of the exchange of genetic information between the different sampled regions. Population structuring suggests the presence of two major groups which do not correlate with their geographic sampling location in Brazil. These results may indicate recent recolonization of C. includens in Brazil or migration patterns following source-sink dynamics. Furthermore, the presence of two groups within C. includens suggests that a study on development of resistance or any other genetic-based trait needs to be evaluated on both groups, and pest management in soybean fields should be aware that differences may come to the control strategies they use.

  10. Evolution of dispersal in spatially and temporally variable environments: The importance of life cycles.

    Science.gov (United States)

    Massol, François; Débarre, Florence

    2015-07-01

    Spatiotemporal variability of the environment is bound to affect the evolution of dispersal, and yet model predictions strongly differ on this particular effect. Recent studies on the evolution of local adaptation have shown that the life cycle chosen to model the selective effects of spatiotemporal variability of the environment is a critical factor determining evolutionary outcomes. Here, we investigate the effect of the order of events in the life cycle on the evolution of unconditional dispersal in a spatially heterogeneous, temporally varying landscape. Our results show that the occurrence of intermediate singular strategies and disruptive selection are conditioned by the temporal autocorrelation of the environment and by the life cycle. Life cycles with dispersal of adults versus dispersal of juveniles, local versus global density regulation, give radically different evolutionary outcomes that include selection for total philopatry, evolutionary bistability, selection for intermediate stable states, and evolutionary branching points. Our results highlight the importance of accounting for life-cycle specifics when predicting the effects of the environment on evolutionarily selected trait values, such as dispersal, as well as the need to check the robustness of model conclusions against modifications of the life cycle. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  11. Nutrition as an important mediator of the impact of background variables on outcome in middle childhood

    Science.gov (United States)

    Kitsao-Wekulo, Patricia; Holding, Penny; Taylor, H. Gerry; Abubakar, Amina; Kvalsvig, Jane; Connolly, Kevin

    2013-01-01

    Adequate nutrition is fundamental to the development of a child's full potential. However, the extent to which malnutrition affects developmental and cognitive outcomes in the midst of co-occurring risk factors remains largely understudied. We sought to establish if the effects of nutritional status varied according to diverse background characteristics as well as to compare the relative strength of the effects of poor nutritional status on language skills, motor abilities, and cognitive functioning at school age. This cross-sectional study was conducted among school-age boys and girls resident in Kilifi District in Kenya. We hypothesized that the effects of area of residence, school attendance, household wealth, age and gender on child outcomes are experienced directly and indirectly through child nutritional status. The use of structural equation modeling (SEM) allowed the disaggregation of the total effect of the explanatory variables into direct effects (effects that go directly from one variable to another) and indirect effects. Each of the models tested for the four child outcomes had a good fit. However, the effects on verbal memory apart from being weaker than for the other outcomes, were not mediated through nutritional status. School attendance was the most influential predictor of nutritional status and child outcomes. The estimated models demonstrated the continued importance of child nutritional status at school-age. PMID:24298246

  12. Beyond Multiplication: Incorporating Importance into Client Satisfaction Measures

    Science.gov (United States)

    Hsieh, Chang-Ming

    2014-01-01

    Objective: This article brings the discussions on incorporating perceived importance across study areas into the study of client satisfaction and cautions the use of multiplicative scores (multiplying satisfaction and importance scores) as a weighting method. An alternative weighting method is provided. Method: Analyze data from a client…

  13. Sources of variability in wideband energy reflectance measurements in adults.

    Science.gov (United States)

    Feeney, M Patrick; Stover, Bert; Keefe, Douglas H; Garinis, Angela C; Day, Jessica E; Seixas, Noah

    2014-05-01

    Wideband acoustic immittance measurements of the middle ear, such as wideband energy reflectance (ER), can provide information about how the middle ear functions across the traditional audiometric frequency range. These measurements are being investigated as a new means of evaluating conductive hearing disorders, and studies have been reported on a number of middle-ear disorders. However, the normative database for wideband ER is still being developed, and more information is needed about sources of test variability. The purpose of the present study was to evaluate sources of variability in wideband ER measurements at baseline and across annual tests for up to 5 yr in subjects with normal hearing. The main group consisted of 112 subjects (187 ears), 24 females and 88 males, with normal hearing and normal 0.226-kHz admittance tympanometry. An additional 24 adults with abnormal 0.226-kHz tympanometry provided baseline comparison data. A longitudinal design was used in obtaining annual measurements of audiometry, tympanometry, and wideband ER at ambient pressure in adults. Clinical audiometry and tympanometry data and 1/3-octave wideband ER measurements were obtained at baseline and annually for up to four additional tests. Descriptive statistics and t-tests were used to explore differences in 1/3-octave baseline ER measures in terms of subject age, test ear, sex, and clinical tympanometry. Longitudinal mixed-effects linear regression models at 1.0, 2.0, and 4.0 kHz were used to examine the different sources of variance affecting ER over time. There were small but statistically significant mean differences in ER for baseline measurements as a function of ear, sex, and age. Compared with these results, data for 29 ears with abnormal 0.226-kHz tympanometry differed from mean normal data across a broad frequency range by as much as 20%. ER varied as a function of peak compensated static acoustic admittance (Ytm) for measures at 1.0 kHz but was unrelated to Ytm at 2.0 and

  14. Relative importance of factors affecting corneal hysteresis measurement.

    Science.gov (United States)

    Sullivan-Mee, Michael; Katiyar, Suchitra; Pensyl, Denise; Halverson, Kathy D; Qualls, Clifford

    2012-05-01

    variables that independently influence CH values, the overall r value indicates that these variables together only explain 40% of CH variability. These results suggest that other significant sources of variability exist and deserve investigation.

  15. Monitoring and identification of sepsis development through a composite measure of heart rate variability.

    Directory of Open Access Journals (Sweden)

    Andrea Bravi

    Full Text Available Tracking the physiological conditions of a patient developing infection is of utmost importance to provide optimal care at an early stage. This work presents a procedure to integrate multiple measures of heart rate variability into a unique measure for the tracking of sepsis development. An early warning system is used to illustrate its potential clinical value. The study involved 17 adults (age median 51 (interquartile range 46-62 who experienced a period of neutropenia following chemoradiotherapy and bone marrow transplant; 14 developed sepsis, and 3 did not. A comprehensive panel (N = 92 of variability measures was calculated for 5 min-windows throughout the period of monitoring (12 ± 4 days. Variability measures underwent filtering and two steps of data reduction with the objective of enhancing the information related to the greatest degree of change. The proposed composite measure was capable of tracking the development of sepsis in 12 out of 14 patients. Simulating a real-time monitoring setting, the sum of the energy over the very low frequency range of the composite measure was used to classify the probability of developing sepsis. The composite revealed information about the onset of sepsis about 60 hours (median value before of sepsis diagnosis. In a real monitoring setting this quicker detection time would be associated to increased efficacy in the treatment of sepsis, therefore highlighting the potential clinical utility of a composite measure of variability.

  16. Importance and challenges of measuring intrinsic foot muscle strength

    Science.gov (United States)

    2012-01-01

    Background Intrinsic foot muscle weakness has been implicated in a range of foot deformities and disorders. However, to establish a relationship between intrinsic muscle weakness and foot pathology, an objective measure of intrinsic muscle strength is needed. The aim of this review was to provide an overview of the anatomy and role of intrinsic foot muscles, implications of intrinsic weakness and evaluate the different methods used to measure intrinsic foot muscle strength. Method Literature was sourced from database searches of MEDLINE, PubMed, SCOPUS, Cochrane Library, PEDro and CINAHL up to June 2012. Results There is no widely accepted method of measuring intrinsic foot muscle strength. Methods to estimate toe flexor muscle strength include the paper grip test, plantar pressure, toe dynamometry, and the intrinsic positive test. Hand-held dynamometry has excellent interrater and intrarater reliability and limits toe curling, which is an action hypothesised to activate extrinsic toe flexor muscles. However, it is unclear whether any method can actually isolate intrinsic muscle strength. Also most methods measure only toe flexor strength and other actions such as toe extension and abduction have not been adequately assessed. Indirect methods to investigate intrinsic muscle structure and performance include CT, ultrasonography, MRI, EMG, and muscle biopsy. Indirect methods often discriminate between intrinsic and extrinsic muscles, but lack the ability to measure muscle force. Conclusions There are many challenges to accurately measure intrinsic muscle strength in isolation. Most studies have measured toe flexor strength as a surrogate measure of intrinsic muscle strength. Hand-held dynamometry appears to be a promising method of estimating intrinsic muscle strength. However, the contribution of extrinsic muscles cannot be excluded from toe flexor strength measurement. Future research should clarify the relative contribution of intrinsic and extrinsic muscles

  17. Proportional Hazards Model with Covariate Measurement Error and Instrumental Variables.

    Science.gov (United States)

    Song, Xiao; Wang, Ching-Yun

    2014-12-01

    In biomedical studies, covariates with measurement error may occur in survival data. Existing approaches mostly require certain replications on the error-contaminated covariates, which may not be available in the data. In this paper, we develop a simple nonparametric correction approach for estimation of the regression parameters in the proportional hazards model using a subset of the sample where instrumental variables are observed. The instrumental variables are related to the covariates through a general nonparametric model, and no distributional assumptions are placed on the error and the underlying true covariates. We further propose a novel generalized methods of moments nonparametric correction estimator to improve the efficiency over the simple correction approach. The efficiency gain can be substantial when the calibration subsample is small compared to the whole sample. The estimators are shown to be consistent and asymptotically normal. Performance of the estimators is evaluated via simulation studies and by an application to data from an HIV clinical trial. Estimation of the baseline hazard function is not addressed.

  18. Importance and challenges of measuring intrinsic foot muscle strength

    OpenAIRE

    Soysa Achini; Hiller Claire; Refshauge Kathryn; Burns Joshua

    2012-01-01

    Abstract Background Intrinsic foot muscle weakness has been implicated in a range of foot deformities and disorders. However, to establish a relationship between intrinsic muscle weakness and foot pathology, an objective measure of intrinsic muscle strength is needed. The aim of this review was to provide an overview of the anatomy and role of intrinsic foot muscles, implications of intrinsic weakness and evaluate the different methods used to measure intrinsic foot muscle strength. Method Li...

  19. CORRECTING FOR MEASUREMENT ERROR IN LATENT VARIABLES USED AS PREDICTORS*

    Science.gov (United States)

    Schofield, Lynne Steuerle

    2015-01-01

    This paper represents a methodological-substantive synergy. A new model, the Mixed Effects Structural Equations (MESE) model which combines structural equations modeling and item response theory is introduced to attend to measurement error bias when using several latent variables as predictors in generalized linear models. The paper investigates racial and gender disparities in STEM retention in higher education. Using the MESE model with 1997 National Longitudinal Survey of Youth data, I find prior mathematics proficiency and personality have been previously underestimated in the STEM retention literature. Pre-college mathematics proficiency and personality explain large portions of the racial and gender gaps. The findings have implications for those who design interventions aimed at increasing the rates of STEM persistence among women and under-represented minorities. PMID:26977218

  20. The importance of measuring psychosocial functioning in schizophrenia

    Directory of Open Access Journals (Sweden)

    Dias Vasco

    2011-06-01

    Full Text Available Abstract Background Schizophrenia is among the most disabling of mental illnesses and frequently causes impaired functioning. We explore issues of definition and terminology, and the relationship between social functioning, cognition, and psychopathology considering relevant research findings. Methods The present article describes measures of social functioning and outlines their psychometric properties. It considers their usefulness in research and clinical settings. Treatment aims and objectives are explored in the context of cognitive and social functioning. Finally, we identify areas for developing research and refining the measurement of social functioning. Results The definition and measurement of social functioning in schizophrenia remains a complex and disputed area. The relationships between symptoms, cognitive functioning and social functioning are complex but we are beginning to understand them better. Scales for measuring functioning in clinical practice must be brief and sensitive to change and the Personal and Social Performance (PSP scale may offer several advantages in these regards. Brief cognitive assessments focusing upon the domains most commonly affected in schizophrenia, such as verbal memory and executive functions, should be coadministered with measures of functioning. Conclusions The use of validated scales for schizophrenia that are sensitive to change over the course of the illness and its treatment, should allow for a better understanding of patients' functional disabilities, enabling better and more comprehensive monitoring and evaluation of both pharmacological and non-pharmacological treatment strategies.

  1. Blood Pressure Variability and Cognitive Function Among Older African Americans: Introducing a New Blood Pressure Variability Measure.

    Science.gov (United States)

    Tsang, Siny; Sperling, Scott A; Park, Moon Ho; Helenius, Ira M; Williams, Ishan C; Manning, Carol

    2017-09-01

    Although blood pressure (BP) variability has been reported to be associated with cognitive impairment, whether this relationship affects African Americans has been unclear. We sought correlations between systolic and diastolic BP variability and cognitive function in community-dwelling older African Americans, and introduced a new BP variability measure that can be applied to BP data collected in clinical practice. We assessed cognitive function in 94 cognitively normal older African Americans using the Mini-Mental State Examination (MMSE) and the Computer Assessment of Mild Cognitive Impairment (CAMCI). We used BP measurements taken at the patients' three most recent primary care clinic visits to generate three traditional BP variability indices, range, standard deviation, and coefficient of variation, plus a new index, random slope, which accounts for unequal BP measurement intervals within and across patients. MMSE scores did not correlate with any of the BP variability indices. Patients with greater diastolic BP variability were less accurate on the CAMCI verbal memory and incidental memory tasks. Results were similar across the four BP variability indices. In a sample of cognitively intact older African American adults, BP variability did not correlate with global cognitive function, as measured by the MMSE. However, higher diastolic BP variability correlated with poorer verbal and incidental memory. By accounting for differences in BP measurement intervals, our new BP variability index may help alert primary care physicians to patients at particular risk for cognitive decline.

  2. Various approaches to standardization and the importance of measurement accuracy

    NARCIS (Netherlands)

    Gram, J.; Jespersen, J.; Kluft, C.; Declerck, P.

    1996-01-01

    Biochemical measurements of quantities, i.e. analytes, of the haemostatic system are the basis of evaluating patients with potentially serious or lifethreatening disorders. Therefore, there is a need of a high level of certainty of the results. Experience based on the comprehensive international

  3. Active Learning: The Importance of Developing a Comprehensive Measure

    Science.gov (United States)

    Carr, Rodney; Palmer, Stuart; Hagel, Pauline

    2015-01-01

    This article reports on an investigation into the validity of a widely used scale for measuring the extent to which higher education students employ active learning strategies. The scale is the active learning scale in the Australasian Survey of Student Engagement. This scale is based on the Active and Collaborative Learning scale of the National…

  4. Measuring the affordability of medicines: Importance and challenges

    NARCIS (Netherlands)

    L.M. Niëns (Laurens); W.B.F. Brouwer (Werner)

    2013-01-01

    markdownabstract__Abstract__ The issue of affordability of health care services remains high on the (health) policy agenda. Determining whether health care services are affordable is complex, however, as the concept 'affordability' is inherently normative. With a focus on measuring affordability

  5. GFT centrality: A new node importance measure for complex networks

    Science.gov (United States)

    Singh, Rahul; Chakraborty, Abhishek; Manoj, B. S.

    2017-12-01

    Identifying central nodes is very crucial to design efficient communication networks or to recognize key individuals of a social network. In this paper, we introduce Graph Fourier Transform Centrality (GFT-C), a metric that incorporates local as well as global characteristics of a node, to quantify the importance of a node in a complex network. GFT-C of a reference node in a network is estimated from the GFT coefficients derived from the importance signal of the reference node. Our study reveals the superiority of GFT-C over traditional centralities such as degree centrality, betweenness centrality, closeness centrality, eigenvector centrality, and Google PageRank centrality, in the context of various arbitrary and real-world networks with different degree-degree correlations.

  6. Sky Background Variability Measured on Maunakea at Gemini North Observatory

    Science.gov (United States)

    Smith, Adam B.; Roth, Katherine; Stephens, Andrew W.

    2016-01-01

    Gemini North has recently implemented a Quality Assessment Pipeline (QAP) that automatically reduces images in realtime to determine sky condition quantities, including background sky brightness from the optical to near-infrared. Processing archived images through the QAP and mining the results allows us to look for trends and systematic issues with the instruments and optics during the first decade of Gemini.Here we present the results of using the QAP calculated values to quantify how airglow affects the background sky brightness of images taken with Gemini's imaging instruments, GMOS and NIRI, as well as searching for other factors that may cause changes in the sky brightness. By investigating the dependence of measured sky brightness as a function of a variety of variables, including time after twilight, airmass, season, distance from the moon, air temperature, etc., we quantify the effect of sky brightness and its impact on the sensitivity of Gemini optical and near-infrared imaging data. These measurements will be used to determine new sky background relationships for Maunakea, and to improve the Gemini Integration Time Calculators (ITCs).

  7. Head lice prevalence among households in Norway: importance of spatial variables and individual and household characteristics.

    Science.gov (United States)

    Rukke, Bjørn Arne; Birkemoe, Tone; Soleng, Arnulf; Lindstedt, Heidi Heggen; Ottesen, Preben

    2011-09-01

    Head lice prevalence varies greatly between and within countries, and more knowledge is needed to approach causes of this variation. In the present study, we investigated head lice prevalence among elementary school students and their households in relation to individual and household characteristics as well as spatial variables. The investigation included households from 5 geographically separated municipalities. Present infestations among household members as well as previous infestations in the household were reported in a questionnaire. In elementary school students prevalence was low (1·63%), but more than one-third of the households (36·43%) had previously experienced pediculosis. Prevalence was higher in elementary school students than in other household members, and highest in third-grade children. Prevalence was also influenced by the school attended, which suggested that interactions between children in the same school are important for head lice transmission. Previous occurrence of head lice in homes also increased the risk of present infestation. Prevalence of previous infestations was higher in households with more children and in more densely populated municipalities, indicating that the density of hosts or groups of hosts influences transmission rates. These results demonstrate that information of hosts' spatial distribution as well as household and individual characteristics is needed to better understand head lice population dynamics.

  8. Predicting the distribution of a threatened albatross: The importance of competition, fisheries and annual variability

    Science.gov (United States)

    Catry, P.; Lemos, R. T.; Brickle, P.; Phillips, R. A.; Matias, R.; Granadeiro, J. P.

    2013-03-01

    The ability to predict the distribution of threatened marine predators is essential to inform spatially explicit seascape management. We tracked 99 individual black-browed albatrosses Thalassarche melanophris from two Falkland Islands’ colonies in 2 years. We modeled the observed distribution of foraging activity taking environmental variables, fisheries activity (derived from vessel monitoring system data), accessibility to feeding grounds and intra-specific competition into account. The resulting models had sufficient generality to make reasonable predictions for different years and colonies, which allows temporal and spatial variation to be incorporated into the decision making process by managers for regions and seasons where available information is incomplete. We also illustrated that long-ranging birds from colonies separated by as little as 75 km can show important spatial segregation at sea, invalidating direct or uncorrected extrapolation from one colony to neighboring ones. Fisheries had limited influence on albatross distribution, despite the well known scavenging behavior of these birds. The models developed here have potentially wide application to the identification of sensitive geographical areas where special management practices (such as fisheries closures) could be implemented, and would predict how these areas are likely to move with annual and seasonal changes in environmental conditions.

  9. The importance of measuring customer satisfaction in palliative care.

    Science.gov (United States)

    Turriziani, Adriana; Attanasio, Gennaro; Scarcella, Francesco; Sangalli, Luisa; Scopa, Anna; Genualdo, Alessandra; Quici, Stefano; Nazzicone, Giulia; Ricciotti, Maria Adelaide; La Commare, Francesco

    2016-03-01

    In the last decades, palliative care has been more and more focused on the evaluation of patients' and families' satisfaction with care. However, the evaluation of customer satisfaction in palliative care presents a number of issues such as the presence of both patients and their families, the frail condition of the patients and the complexity of their needs, and the lack of standard quality indicators and appropriate measurement tools. In this manuscript, we critically review existing evidence and literature on the evaluation of satisfaction in the palliative care context. Moreover, we provide - as a practical example - the preliminary results of our experience in this setting with the development of a dedicated tool for the measurement of satisfaction.

  10. Preanalytical factors of importance for measurement of Chromogranin A

    DEFF Research Database (Denmark)

    Pedersen, Lise; Nybo, Mads

    2014-01-01

    BACKGROUND: Studies indicate that fasting and diurnal variation can influence serum Chromogranin A (CgA) concentrations and furthermore, stability of the CgA molecule has been questioned. We investigated the impact of pre-analytical conditions on a CgA assay. METHODS: Serum CgA concentrations were....../mL with a reference interval of 30.3-94.4 ng/mL (2.5-97.5 percentile). CONCLUSIONS: Fasting does not influence CgA concentrations significantly, while sample stability is a major issue with the assay tested. The biological variation of CgA was defined and a reference interval was established....... measured in blood samples collected from ten healthy subjects at three time points during three days with and without fasting. Samples were kept at 4°C and re-measured after 24 and 48 h in order to test the stability of the measured epitopes. For establishment of a reference interval, serum samples were...

  11. Screening for lifetime concussion in athletes: importance of oculomotor measures.

    Science.gov (United States)

    Poltavski, Dmitri V; Biberdorf, David

    2014-01-01

    The purpose of the present study was to determine the utility of oculomotor-based evaluation protocols in screening for lifetime concussion incidence in elite hockey players. Forty-two Division I collegiate male and female hockey players were evaluated using the guidelines of an overall oculomotor-based diagnostic clinical test protocol for the mTBI population. The sensitivity of the collected measures to lifetime concussion was then compared with the corresponding sensitivity of measures of neuropsychological functioning (ImPACT) often used with athletes for acute concussion diagnosis. This model showed that a hockey player with a Near Point of Fixation Disparity (NPFD) equal to or greater than 15 cm, Visagraph comprehension rate less than 85% and the total score on part A of an ADHD questionnaire equal to or greater than 11 was on average 10.72-times more likely to have previously suffered a concussion than an athlete with lower values on the NPFD and ADHD questionnaire and a higher comprehension rate on the Visagraph. None of the IMPACT baseline assessment measures were significantly predictive of the individual's concussion history. The study provides a relatively sensitive screening tool to assess the probability of previous concussion(s) in an athlete. This model may allow athletic personnel to address in a timely manner the risks associated with repeat concussions and to develop individualized concussion management protocols.

  12. VLBA Trigonometric Parallax Measurement of the Semi-regular Variable RT Vir

    Science.gov (United States)

    Zhang, Bo; Zheng, Xingwu; Reid, Mark J.; Honma, Mareki; Menten, Karl M.; Brunthaler, Andreas; Kim, Jaeheon

    2017-11-01

    We report a trigonometric parallax measurement of 22 GHz H2O masers toward the semi-regular variable RT Vir from multi-epoch Very Long Baseline Array observations. The parallax of 4.417 ± 0.134 mas, corresponding to a distance of 226 ± 7 pc, is significantly different from the Hipparcos parallax, but is consistent with a distance derived from the period-luminosity relation (PLR). This suggests that the Hipparcos parallax suffers from systematic bias, possibly owing to a variable photo-center for this giant star. As such, VLBI parallax measurements will serve as an important cross-check for Gaia. Combing our RT Vir parallax with other long period variable parallaxes, we find a Galactic PLR at an infrared K band of {M}K=-3.52{log}P+(1.10+/- 0.08), assuming that the slope of the Large Magellanic Cloud relation is the same to that of our Galaxy.

  13. The importance of puberty for adolescent development: conceptualization and measurement.

    Science.gov (United States)

    Berenbaum, Sheri A; Beltz, Adriene M; Corley, Robin

    2015-01-01

    How and why are teenagers different from children and adults? A key question concerns the ways in which pubertal development shapes psychological changes in adolescence directly through changes to the brain and indirectly through the social environment. Empirical work linking pubertal development to adolescent psychological function draws from several different perspectives, often with varying approaches and a focus on different outcomes and mechanisms. The main themes concern effects of atypical pubertal timing on behavior problems during adolescence, effects of pubertal status (and associated hormones) on normative changes in behaviors that can facilitate or hinder development (especially risk-taking, social reorientation, and stress responsivity), and the role of puberty in triggering psychopathology in vulnerable individuals. There is also interest in understanding the ways in which changes in the brain reflect pubertal processes and underlie psychological development in adolescence. In this chapter, we consider the ways that puberty might affect adolescent psychological development, and why this is of importance to developmentalists. We describe the processes of pubertal development; summarize what is known about pubertal influences on adolescent development; consider the assumptions that underlie most work and the methodological issues that affect the interpretation of results; and propose research directions to help understand paths from puberty to behavior. Throughout, we emphasize the importance of pubertal change in all aspects of psychological development, and the ways in which puberty represents an opportunity to study the interplay of biological and social influences. © 2015 Elsevier Inc. All rights reserved.

  14. A novel method for importance measure analysis in the presence of epistemic and aleatory uncertainties

    Directory of Open Access Journals (Sweden)

    Ren Bo

    2014-06-01

    Full Text Available For structural systems with both epistemic and aleatory uncertainties, research on quantifying the contribution of the epistemic and aleatory uncertainties to the failure probability of the systems is conducted. Based on the method of separating epistemic and aleatory uncertainties in a variable, the core idea of the research is firstly to establish a novel deterministic transition model for auxiliary variables, distribution parameters, random variables, failure probability, then to propose the improved importance sampling (IS to solve the transition model. Furthermore, the distribution parameters and auxiliary variables are sampled simultaneously and independently; therefore, the inefficient sampling procedure with an “inner-loop” for epistemic uncertainty and an “outer-loop” for aleatory uncertainty in traditional methods is avoided. Since the proposed method combines the fast convergence of the proper estimates and searches failure samples in the interesting regions with high efficiency, the proposed method is more efficient than traditional methods for the variance-based failure probability sensitivity measures in the presence of epistemic and aleatory uncertainties. Two numerical examples and one engineering example are introduced for demonstrating the efficiency and precision of the proposed method for structural systems with both epistemic and aleatory uncertainties.

  15. THE IMPORTANCE OF MEASURING INDIVIDUAL PERFORMANCE TO INCREASE ORGANIZATIONAL PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Ecaterina Livia TĂTAR

    2011-01-01

    Full Text Available Management theory and practice suggest a wide range of instruments used in organizations in order to measure performance, whether individual or organizational. The purpose of this paper is to mention some of these tools, with an emphasis on the balanced scorecard. Although numerous organizations have adopted the balanced scorecard as a means to increase organizational performance, few of them have succeeded in making it really work. Moreover, individual performance appraisal is often regarded as a coercive instrument rather than a procedure meant to foster the employee’s performance which, in turn, should contribute to enhancing the organization’s overall performance. The hereby article aims at highlighting some of the advantages, as well as shortcomings of the balanced scorecard, followed by drawing conclusions regarding the way in which the balanced scorecard can and must contribute to organization’s well being.

  16. The Relative Importance of Socioeconomic and Political Variables for Public Policy

    Science.gov (United States)

    Lewis-Beck, Michael S.

    1977-01-01

    Argues that comparison of "effects coefficients" derived from path analysis is the preferred method of assessing the relative impact of different independent variables on a given dependent variable. Available from: American Political Science Association, 1527 New Hampshire Avenue, N.W., Washington, DC 20036; $10.50 single copy.…

  17. Variability in Adaptive Behavior in Autism: Evidence for the Importance of Family History

    Science.gov (United States)

    Mazefsky, Carla A.; Williams, Diane L.; Minshew, Nancy J.

    2008-01-01

    Adaptive behavior in autism is highly variable and strongly related to prognosis. This study explored family history as a potential source of variability in adaptive behavior in autism. Participants included 77 individuals (mean age = 18) with average or better intellectual ability and autism. Parents completed the Family History Interview about…

  18. Importance of the macroeconomic variables for variance prediction: A GARCH-MIDAS approach

    DEFF Research Database (Denmark)

    Asgharian, Hossein; Hou, Ai Jun; Javed, Farrukh

    2013-01-01

    This paper aims to examine the role of macroeconomic variables in forecasting the return volatility of the US stock market. We apply the GARCH-MIDAS (Mixed Data Sampling) model to examine whether information contained in macroeconomic variables can help to predict short-term and long...

  19. A novel topological centrality measure capturing biologically important proteins.

    Science.gov (United States)

    Karabekmez, Muhammed Erkan; Kirdar, Betul

    2016-02-01

    Topological centrality in protein interaction networks and its biological implications have widely been investigated in the past. In the present study, a novel metric of centrality-weighted sum of loads eigenvector centrality (WSL-EC)-based on graph spectra is defined and its performance in identifying topologically and biologically important nodes is comparatively investigated with common metrics of centrality in a human protein-protein interaction network. The metric can capture nodes from peripherals of the network differently from conventional eigenvector centrality. Different metrics were found to selectively identify hub sets that are significantly associated with different biological processes. The widely accepted metrics degree centrality, betweenness centrality, subgraph centrality and eigenvector centrality are subject to a bias towards super-hubs, whereas WSL-EC is not affected by the presence of super-hubs. WSL-EC outperforms other metrics of centrality in detecting biologically central nodes such as pathogen-interacting, cancer, ageing, HIV-1 or disease-related proteins and proteins involved in immune system processes and autoimmune diseases in the human interactome.

  20. Variability of adjacency effects in sky reflectance measurements.

    Science.gov (United States)

    Groetsch, Philipp M M; Gege, Peter; Simis, Stefan G H; Eleveld, Marieke A; Peters, Steef W M

    2017-09-01

    Sky reflectance Rsky(λ) is used to correct in situ reflectance measurements in the remote detection of water color. We analyzed the directional and spectral variability in Rsky(λ) due to adjacency effects against an atmospheric radiance model. The analysis is based on one year of semi-continuous Rsky(λ) observations that were recorded in two azimuth directions. Adjacency effects contributed to Rsky(λ) dependence on season and viewing angle and predominantly in the near-infrared (NIR). For our test area, adjacency effects spectrally resembled a generic vegetation spectrum. The adjacency effect was weakly dependent on the magnitude of Rayleigh- and aerosol-scattered radiance. The reflectance differed between viewing directions 5.4±6.3% for adjacency effects and 21.0±19.8% for Rayleigh- and aerosol-scattered Rsky(λ) in the NIR. Under which conditions in situ water reflectance observations require dedicated correction for adjacency effects is discussed. We provide an open source implementation of our method to aid identification of such conditions.

  1. Measuring Networking as an Outcome Variable in Undergraduate Research Experiences

    Science.gov (United States)

    Hanauer, David I.; Hatfull, Graham

    2015-01-01

    The aim of this paper is to propose, present, and validate a simple survey instrument to measure student conversational networking. The tool consists of five items that cover personal and professional social networks, and its basic principle is the self-reporting of degrees of conversation, with a range of specific discussion partners. The networking instrument was validated in three studies. The basic psychometric characteristics of the scales were established by conducting a factor analysis and evaluating internal consistency using Cronbach’s alpha. The second study used a known-groups comparison and involved comparing outcomes for networking scales between two different undergraduate laboratory courses (one involving a specific effort to enhance networking). The final study looked at potential relationships between specific networking items and the established psychosocial variable of project ownership through a series of binary logistic regressions. Overall, the data from the three studies indicate that the networking scales have high internal consistency (α = 0.88), consist of a unitary dimension, can significantly differentiate between research experiences with low and high networking designs, and are related to project ownership scales. The ramifications of the networking instrument for student retention, the enhancement of public scientific literacy, and the differentiation of laboratory courses are discussed. PMID:26538387

  2. Spatial heterogeneity in ecologically important climate variables at coarse and fine scales in a high-snow mountain landscape.

    Science.gov (United States)

    Ford, Kevin R; Ettinger, Ailene K; Lundquist, Jessica D; Raleigh, Mark S; Hille Ris Lambers, Janneke

    2013-01-01

    Climate plays an important role in determining the geographic ranges of species. With rapid climate change expected in the coming decades, ecologists have predicted that species ranges will shift large distances in elevation and latitude. However, most range shift assessments are based on coarse-scale climate models that ignore fine-scale heterogeneity and could fail to capture important range shift dynamics. Moreover, if climate varies dramatically over short distances, some populations of certain species may only need to migrate tens of meters between microhabitats to track their climate as opposed to hundreds of meters upward or hundreds of kilometers poleward. To address these issues, we measured climate variables that are likely important determinants of plant species distributions and abundances (snow disappearance date and soil temperature) at coarse and fine scales at Mount Rainier National Park in Washington State, USA. Coarse-scale differences across the landscape such as large changes in elevation had expected effects on climatic variables, with later snow disappearance dates and lower temperatures at higher elevations. However, locations separated by small distances (∼20 m), but differing by vegetation structure or topographic position, often experienced differences in snow disappearance date and soil temperature as great as locations separated by large distances (>1 km). Tree canopy gaps and topographic depressions experienced later snow disappearance dates than corresponding locations under intact canopy and on ridges. Additionally, locations under vegetation and on topographic ridges experienced lower maximum and higher minimum soil temperatures. The large differences in climate we observed over small distances will likely lead to complex range shift dynamics and could buffer species from the negative effects of climate change.

  3. Spatial heterogeneity in ecologically important climate variables at coarse and fine scales in a high-snow mountain landscape.

    Directory of Open Access Journals (Sweden)

    Kevin R Ford

    Full Text Available Climate plays an important role in determining the geographic ranges of species. With rapid climate change expected in the coming decades, ecologists have predicted that species ranges will shift large distances in elevation and latitude. However, most range shift assessments are based on coarse-scale climate models that ignore fine-scale heterogeneity and could fail to capture important range shift dynamics. Moreover, if climate varies dramatically over short distances, some populations of certain species may only need to migrate tens of meters between microhabitats to track their climate as opposed to hundreds of meters upward or hundreds of kilometers poleward. To address these issues, we measured climate variables that are likely important determinants of plant species distributions and abundances (snow disappearance date and soil temperature at coarse and fine scales at Mount Rainier National Park in Washington State, USA. Coarse-scale differences across the landscape such as large changes in elevation had expected effects on climatic variables, with later snow disappearance dates and lower temperatures at higher elevations. However, locations separated by small distances (∼20 m, but differing by vegetation structure or topographic position, often experienced differences in snow disappearance date and soil temperature as great as locations separated by large distances (>1 km. Tree canopy gaps and topographic depressions experienced later snow disappearance dates than corresponding locations under intact canopy and on ridges. Additionally, locations under vegetation and on topographic ridges experienced lower maximum and higher minimum soil temperatures. The large differences in climate we observed over small distances will likely lead to complex range shift dynamics and could buffer species from the negative effects of climate change.

  4. Spatial-temporal gait variability poststroke: variations in measurement and implications for measuring change.

    Science.gov (United States)

    Chisholm, Amanda E; Makepeace, Shelley; Inness, Elizabeth L; Perry, Stephen D; McIlroy, William E; Mansfield, Avril

    2014-07-01

    To determine the responsiveness to change of spatial-temporal gait parameters among stroke survivors for 3 different variability measures: SD, coefficient of variation (CV), and median absolute deviation (MAD). Retrospective chart review. Clinical laboratory in a Canadian hospital. Stroke survivors (N=74) receiving inpatient rehabilitation. Not applicable. Spatial-temporal gait variability was calculated for step length, step width, stance time, swing time, and double support time. Responsiveness to change was determined by comparing (1) trials without versus trials with a concurrent cognitive task and (2) admission to discharge from rehabilitation. Variability estimators (SD, CV, and MAD) increased with the addition of a cognitive task and decreased from admission to discharge of rehabilitation. However, these changes were not statistically significant when change in gait velocity was included as a covariate. The effect size values were similar for all variability estimators with a trend toward a greater SD response to temporal parameters. The CV displayed a larger response to change for step length than did the SD and MAD. Although gait variability decreased between admission and discharge, the effect size was larger for the condition without the cognitive task than for the condition with the cognitive task. Our results show that gait variability estimators demonstrate a similar responsiveness to a concurrent cognitive task and improved walking ability with recovery from stroke. Future work may focus on evaluating the clinical utility of these measures in relation to informing therapy and response to gait-specific training protocols. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  5. The Relationship between Psychosocial Variables and Measures of ...

    African Journals Online (AJOL)

    Background: Fibromyalgia is considered to be a multifactorial condition in which a number of biological and psychological variables interact. However, the exact pathogenesis and effective treatment of fibromyalgia are still unknown. In this study the relationship between psychosocial variables of self-efficacy, helplessness, ...

  6. Handling ordinal variables in three-way analysis of quantification matrices for variables of mixed measurement levels

    NARCIS (Netherlands)

    Kiers, Henk A.L.

    For the analysis of variables of mixed measurement levels a class of methods can be used that is based on three-way analysis of quantification matrices for nominal or quantitative variables. This class of methods incorporates some well-known techniques but also offers a series of interesting new

  7. Measuring Networking as an Outcome Variable in Undergraduate Research Experiences.

    Science.gov (United States)

    Hanauer, David I; Hatfull, Graham

    2015-01-01

    The aim of this paper is to propose, present, and validate a simple survey instrument to measure student conversational networking. The tool consists of five items that cover personal and professional social networks, and its basic principle is the self-reporting of degrees of conversation, with a range of specific discussion partners. The networking instrument was validated in three studies. The basic psychometric characteristics of the scales were established by conducting a factor analysis and evaluating internal consistency using Cronbach's alpha. The second study used a known-groups comparison and involved comparing outcomes for networking scales between two different undergraduate laboratory courses (one involving a specific effort to enhance networking). The final study looked at potential relationships between specific networking items and the established psychosocial variable of project ownership through a series of binary logistic regressions. Overall, the data from the three studies indicate that the networking scales have high internal consistency (α = 0.88), consist of a unitary dimension, can significantly differentiate between research experiences with low and high networking designs, and are related to project ownership scales. The ramifications of the networking instrument for student retention, the enhancement of public scientific literacy, and the differentiation of laboratory courses are discussed. © 2015 D. I. Hanauer and G. Hatfull. CBE—Life Sciences Education © 2015 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  8. Comparison of seasonal variability in European domestic radon measurements

    Directory of Open Access Journals (Sweden)

    C. J. Groves-Kirkby

    2010-03-01

    Full Text Available Analysis of published data characterising seasonal variability of domestic radon concentrations in Europe and elsewhere shows significant variability between different countries and between regions where regional data is available. Comparison is facilitated by application of the Gini Coefficient methodology to reported seasonal variation data. Overall, radon-rich sedimentary strata, particularly high-porosity limestones, exhibit high seasonal variation, while radon-rich igneous lithologies demonstrate relatively constant, but somewhat higher, radon concentrations. High-variability regions include the Pennines and South Downs in England, Languedoc and Brittany in France, and especially Switzerland. Low-variability high-radon regions include the granite-rich Cornwall/Devon peninsula in England, and Auvergne and Ardennes in France, all components of the Devonian-Carboniferous Hercynian belt.

  9. Examining the importance of endmember class and spectra variability in unmixing analysis for mapping urban impervious surfaces

    Science.gov (United States)

    Li, Wenliang

    2017-12-01

    Impervious surface is considered as a key indicator for evaluating urbanization intensity and environmental quality. For mapping impervious surfaces, spectral mixture analysis has been widely applied because of its effectiveness in addressing the mixed pixel problem. For spectral mixture analysis, endmember class and spectra variability have been recognized as profound error sources. In order to address these challenging problems, many techniques have been developed in recent years. While the proposed methods have proven valuable for mapping impervious surface fractions, the importance of endmember class and spectra variability in unmixing analysis is still not clear yet. In this study, I implemented five typical temporal mixture analysis models with different considerations of endmember class and endmember spectra variability. In particular, I evaluated the modelling performance of all five temporal mixture analysis models through visual examination and quantitative analysis. Furthermore, a detailed modelling performance comparison has been conducted for the overall area and both developed and less developed areas to examine the importance of endmember class and endmember spectral variability in unmixing analysis for mapping impervious surfaces. Analysis results suggest that all five proposed temporal mixture analysis models have achieved a promising performance for mapping impervious surfaces. Moreover, the performance comparison results show that the endmember class variability is more important for less developed areas and the endmember spectra variability is more important for developed areas.

  10. A variability study of computerized sagittal spinopelvic radiologic measurements of trunk balance.

    Science.gov (United States)

    Berthonnaud, E; Labelle, H; Roussouly, P; Grimard, G; Vaz, G; Dimnet, J

    2005-02-01

    The accurate measurement of spinal and pelvic alignment in the sagittal plane is of prime importance for various disorders. Pelvic incidence (PI) is a fundamental anatomic parameter that is specific and constant for each adult individual and is related to pelvic orientation as well as to the size of lumbar lordosis (LL). It is the summation of the sacral slope (SS) and pelvic tilt (PT), two position-dependent variables that determine pelvic orientation in the sagittal plane. The authors have proposed a computer software designed to measure PI, SS, PT, LL, and thoracic kyphosis (TK) on standardized standing lateral digitized x-rays of the spine and pelvis. The purpose of this study was to evaluate the inter- and intraobserver variability of measurements using this software, to determine if it can be used reliably in a clinical environment. The standing lateral x-rays of 30 subjects were randomly selected from the database of two medical institutions. The normal population had standard radiographs on which the various pertinent landmarks were marked by one operator prior to digitization, whereas the scoliotic population had digital radiographs that obviated the need for prior marking of landmarks. Four individuals measured all variables on the 30 x-rays on two occasions, with a 15-day interval between the two sessions. Statistical analysis was done with intraclass correlation coefficients (ICCs). The ICC measured within observers was between 0.93 and 0.99, whereas the ICC between observers varied between 0.92 and 0.99. The variations observed were similar for normal and scoliotic subjects, and prior marking of the x-rays had no significant influence. We conclude that the variability of measurements with this method is lower than with similar radiologic measures done manually and that the use of this software can be recommended for future clinical and research studies of spinopelvic sagittal balance.

  11. The importance of pre-measurements of wellbeing and achievement for students' current wellbeing

    Directory of Open Access Journals (Sweden)

    Karen Van Petegem

    2008-11-01

    Full Text Available Educational effectiveness research focuses not only on cognitive output but also on affective student outcomes. Student wellbeing has to be addressed as an important output variable of the educational process. The focus in this study is on student wellbeing at the end of Grade 10 and its relationship to current achievement, and pre-measurements of student wellbeing and achievement. Student characteristics and motives for attending school are taken into account. Moreover, within classroom environment research, student perceptions of psychosocial characteristics within the classroom are considered as an important factor in the explanation of student wellbeing. Data from 429 students at 13 different secondary technical and vocational training schools in Flanders (Belgium are used. The results indicated that pre-measurements of student wellbeing and achievement are positively related to student wellbeing at the end of Grade 10. No relationship was found between student wellbeing and achievement when both are measured at the end of Grade 10. Furthermore, students feel better when they perceive their teacher's interpersonal behaviour in the classroom as tolerant/authoritative and not as authoritarian.

  12. Graphometric variables of one's signature: I. Basic measures.

    Science.gov (United States)

    Aström, J; Thorell, L H

    2007-12-01

    This study focused on statistical properties and interrelationships of graphometric variables of the signatures of outpatients, 100 men and 119 women, remitted from somatic and psychiatric clinics for possible psychotherapy or for tests of IQ, personality, or brain lesions. The patients' signature on test forms were used. The type of handwriting was classified into Common, Print and Block letters, quantified in breadth, length, and area and grades of slant of minuscules ("lower-case letters") and majuscules ("upper-case"). Analysis indicated sex and age played roles in style of handwriting and size of letters; writing styles differed on most graphometric variables; and meaningful patterns of interrelationships among graphometric variables were specified by factor analysis.

  13. The response of macro variables of emerging and developed oil importers to oil price movements

    OpenAIRE

    Taghizadeh-Hesary, Farhad; Yoshino, Naoyuki; Hossein Abadi, Majid Mohammadi; Farboudmanesh, Rosa

    2015-01-01

    This paper assesses the impact of crude oil price movements on two macro variables - the gross domestic product (GDP) growth rate and consumer price index inflation rate - in the developed economies of the United States and Japan, and an emerging economy, the People's Republic of China (PRC). These countries were chosen for this research because they are the world's three largest oil consumers. The main objective of this study is to see whether these economies are still reactive to oil price ...

  14. Identification of Important Process Variables for Fiber Spinning of Protein Nanotubes Generated from Waste Materials

    Science.gov (United States)

    2012-01-11

    Hydrochloric acid HPLC High-performance liquid chromatography IPA isopropanol MC10 Microcon 10 MeOH Methanol MES 2-[N-morpholino...composites. Vegetable or plant -based natural fibers including flax, hemp, cotton, sisal, and kenaf11 and animal-based natural fibers including wool...to steel, enzyme ( protease ) resistant, have variable and potentially tailorable structural features (length and morphologies), and have potential

  15. Same same but different - quantifying the importance of intra-specific variability to plankton biodiversity

    Science.gov (United States)

    Menden-Deuer, S.; Rowlett, J. M.

    2016-02-01

    Planktonic microbes are vastly more diverse than theoretically explicable (Hutchinson 1961). We recently suggested that intra-specific variability was the key characteristic that allowed co-existence of dozens of planktonic species because the outcome of competitions between individuals with variable competitive abilities was unpredictable (Menden-Deuer and Rowlett 2014). Building on this game-theoretic model, here we examine the quantitative consequences of different degrees of intra-specific variability on species survival and co-existence probability. Frequency distributions of species competitive abilities (i.e. species behavior distributions SBD) vary, including invariant distributions with each individual's competitive ability identical to the mean to entirely bimodal distributions, consisting only of individuals with the highest and lowest competitive ability. In total, we explore the effect of 14 different SBDs on species survival probability in individual-based competition model simulations across varying durations and population sizes. We find that particularly at small population sizes intra-specific diversity enhances survival probability and for some SBDs extinctions are not observed. These results have implications for anticipating species ability to withstand changing environmental conditions and understand diverse planktonic communities in a seemingly uniform ocean.

  16. Measuring spatial variability of land use associated with ...

    African Journals Online (AJOL)

    2011-06-07

    use system is linked to orderly .... i.e., the probability of an urban area occurring around a city centre (Chen et al., 2010). ..... represents around 53% of the maximum degree of land-use spa- tial variability. This means that ...

  17. Continuous measurement of heart rate variability following carbon ...

    African Journals Online (AJOL)

    2010-07-16

    Jul 16, 2010 ... Power spectral analysis of the electrocardiographic R-R interval [heart rate variability: (HRV)] is a well known, non- invasive method for assessing autonomic nervous activity.1. Studies using HRV analysis during positive-pressure pneumoperitoneum (PPP) have demonstrated increased sympathetic ...

  18. Measuring spatial variability of land use associated with ...

    African Journals Online (AJOL)

    2011-06-07

    Jun 7, 2011 ... Decision making for water resources is needed for land-use change due to urbanisation, which impacts hydrological variables such as ...... Values showing relationships between return period, risk of failure, increase in runoff and entropy. T = return period. (years). R = Risk (of failure due to flooding). URB ( ...

  19. Continuous measurement of heart rate variability following carbon ...

    African Journals Online (AJOL)

    Background: Previous studies of autonomic nervous system activity through analysis of heart rate variability (HRV) have demonstrated increased sympathetic activity during positive-pressure pneumoperitoneum. We employed an online, continuous method for rapid HRV analysis (MemCalc™, Tarawa, Suwa Trust, Tokyo, ...

  20. Spectral measurement using IC-compatible linear variable optical filter

    NARCIS (Netherlands)

    Emadi, A.; Grabarnik, S.; Wu, H.; De Graaf, G.; Hedsten, K.; Enoksson, P.; Correia, J.H.; Wolffenbuttel, R.F.

    2010-01-01

    This paper reports on the functional and spectral characterization of a microspectrometer based on a CMOS detector array covered by an IC-Compatible Linear Variable Optical Filter (LVOF). The Fabry-Perot LVOF is composed of 15 dielectric layers with a tapered middle cavity layer, which has been

  1. Evaluating Welfare Effects of Rice Import Quota in Japan: Based on Measuring Non-Tariff Barriers of SBS Rice Imports

    Directory of Open Access Journals (Sweden)

    Qianhui Gao

    2016-08-01

    Full Text Available The principal objective of this study is to analyze welfare effects of Japan’s rice import quota focusing on the simultaneous buy and sell (SBS of the rice importation minimum access (MA policy. Based on the utility function specified in this study, the constructed model is adopted to measure consumption patterns through estimating elasticity of substitution between imported rice and Japan’s domestic rice, and consumers’ preference parameters for different kinds of rice. The results showed that Japanese households prefer domestic rice to the imported rice. Besides, three scenarios of adjusting rice quota volumes were carried out to examine the changes in consumer prices of imported rice and Japanese consumers’ welfares. The results revealed that tariff equivalents of the SBS import quota almost doubled the scale of the mark-up, and the intervention by the Ministry of Agriculture of Japan did cause non-tariff barriers to trade (NTBs. Finally, if the SBS rice quota quantity was fixed at or larger than 180 thousand tons every fiscal year, the consumer prices of imported rice in Japan’s market would decrease to be less than the prices of Japan’s domestic rice, and therefore the imported rice would have more price advantages in this scenario.

  2. What weather variables are important in predicting heat-related mortality? A new application of statistical learning methods.

    Science.gov (United States)

    Zhang, Kai; Li, Yun; Schwartz, Joel D; O'Neill, Marie S

    2014-07-01

    Hot weather increases risk of mortality. Previous studies used different sets of weather variables to characterize heat stress, resulting in variation in heat-mortality associations depending on the metric used. We employed a statistical learning method - random forests - to examine which of the various weather variables had the greatest impact on heat-related mortality. We compiled a summertime daily weather and mortality counts dataset from four U.S. cities (Chicago, IL; Detroit, MI; Philadelphia, PA; and Phoenix, AZ) from 1998 to 2006. A variety of weather variables were ranked in predicting deviation from typical daily all-cause and cause-specific death counts. Ranks of weather variables varied with city and health outcome. Apparent temperature appeared to be the most important predictor of heat-related mortality for all-cause mortality. Absolute humidity was, on average, most frequently selected as one of the top variables for all-cause mortality and seven cause-specific mortality categories. Our analysis affirms that apparent temperature is a reasonable variable for activating heat alerts and warnings, which are commonly based on predictions of total mortality in next few days. Additionally, absolute humidity should be included in future heat-health studies. Finally, random forests can be used to guide the choice of weather variables in heat epidemiology studies. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Important aspects of Eastern Mediterranean large-scale variability revealed from data of three fixed observatories

    Science.gov (United States)

    Bensi, Manuel; Velaoras, Dimitris; Cardin, Vanessa; Perivoliotis, Leonidas; Pethiakis, George

    2015-04-01

    Long-term variations of temperature and salinity observed in the Adriatic and Aegean Seas seem to be regulated by larger-scale circulation modes of the Eastern Mediterranean (EMed) Sea, such as the recently discovered feedback mechanisms, namely the BiOS (Bimodal Oscillating System) and the internal thermohaline pump theories. These theories are the results of interpretation of many years' observations, highlighting possible interactions between two key regions of the EMed. Although repeated oceanographic cruises carried out in the past or planned for the future are a very useful tool for understanding the interaction between the two basins (e.g. alternating dense water formation, salt ingressions), recent long time-series of high frequency (up to 1h) sampling have added valuable information to the interpretation of internal mechanisms for both areas (i.e. mesoscale eddies, evolution of fast internal processes, etc.). During the last 10 years, three deep observatories were deployed and maintained in the Adriatic, Ionian, and Aegean Seas: they are respectively, the E2-M3A, the Pylos, and the E1-M3A. All are part of the largest European network of Fixed Point Open Ocean Observatories (FixO3, http://www.fixo3.eu/). Herein, from the analysis of temperature and salinity, and potential density time series collected at the three sites from the surface down to the intermediate and deep layers, we will discuss the almost perfect anti-correlated behavior between the Adriatic and the Aegean Seas. Our data, collected almost continuously since 2006, reveal that these observatories well represent the thermohaline variability of their own areas. Interestingly, temperature and salinity in the intermediate layer suddenly increased in the South Adriatic from the end of 2011, exactly when they started decreasing in the Aegean Sea. Moreover, Pylos data used together with additional ones (e.g. Absolute dynamic topography, temperature and salinity data from other platforms) collected

  4. Importance of Variable Density and Non-Boussinesq Effects on the Drag of Spherical Particles

    Science.gov (United States)

    Ganguli, Swetava; Lele, Sanjiva

    2017-11-01

    What are the forces that act on a particle as it moves in a fluid? How do they change in the presence of significant heat transfer from the particle, a variable density fluid or gravity? Last year, using particle-resolved simulations we quantified these effects on a single spherical particle and on particles in periodic lattices when O(10-3) 50%) in the absolute drag are observed as λ approaches unity. Oppenheimer, et al. (2016) [1] have proposed a theoretical formula for the drag of a heated sphere at extremely low Re. We show that when Re >O(10), inertial effects completely dominate the drag while when Re zero volumetric dilation rate. In the limit of λ approaching 0 (Stokes' limit), the drag modification can also be captured as a correction to Stokes' drag using a suitable scaling based on the dilation rate. Stanford University - Predictive Science Academic Alliance Program (PSSAP II).

  5. Importance of Various Training-Load Measures in Injury Incidence of Professional Rugby League Athletes.

    Science.gov (United States)

    Thornton, Heidi R; Delaney, Jace A; Duthie, Grant M; Dascombe, Ben J

    2017-07-01

    To investigate the ability of various internal and external training-load (TL) monitoring measures to predict injury incidence among positional groups in professional rugby league athletes. TL and injury data were collected across 3 seasons (2013-2015) from 25 players competing in National Rugby League competition. Daily TL data were included in the analysis, including session rating of perceived exertion (sRPE-TL), total distance (TD), high-speed-running distance (>5 m/s), and high-metabolic-power distance (HPD; >20 W/kg). Rolling sums were calculated, nontraining days were removed, and athletes' corresponding injury status was marked as "available" or "unavailable." Linear (generalized estimating equations) and nonlinear (random forest; RF) statistical methods were adopted. Injury risk factors varied according to positional group. For adjustables, the TL variables associated most highly with injury were 7-d TD and 7-d HPD, whereas for hit-up forwards they were sRPE-TL ratio and 14-d TD. For outside backs, 21- and 28-d sRPE-TL were identified, and for wide-running forwards, sRPE-TL ratio. The individual RF models showed that the importance of the TL variables in injury incidence varied between athletes. Differences in risk factors were recognized between positional groups and individual athletes, likely due to varied physiological capacities and physical demands. Furthermore, these results suggest that robust machine-learning techniques can appropriately monitor injury risk in professional team-sport athletes.

  6. Importance of ocean mesoscale variability for air-sea interactions in the Gulf of Mexico

    Science.gov (United States)

    Putrasahan, D. A.; Kamenkovich, I.; Le Hénaff, M.; Kirtman, B. P.

    2017-06-01

    Mesoscale variability of currents in the Gulf of Mexico (GoM) can affect oceanic heat advection and air-sea heat exchanges, which can influence climate extremes over North America. This study is aimed at understanding the influence of the oceanic mesoscale variability on the lower atmosphere and air-sea heat exchanges. The study contrasts global climate model (GCM) with 0.1° ocean resolution (high resolution; HR) with its low-resolution counterpart (1° ocean resolution with the same 0.5° atmosphere resolution; LR). The LR simulation is relevant to current generation of GCMs that are still unable to resolve the oceanic mesoscale. Similar to observations, HR exhibits positive correlation between sea surface temperature (SST) and surface turbulent heat flux anomalies, while LR has negative correlation. For HR, we decompose lateral advective heat fluxes in the upper ocean into mean (slowly varying) and mesoscale-eddy (fast fluctuations) components. We find that the eddy flux divergence/convergence dominates the lateral advection and correlates well with the SST anomalies and air-sea latent heat exchanges. This result suggests that oceanic mesoscale advection supports warm SST anomalies that in turn feed surface heat flux. We identify anticyclonic warm-core circulation patterns (associated Loop Current and rings) which have an average diameter of 350 km. These warm anomalies are sustained by eddy heat flux convergence at submonthly time scales and have an identifiable imprint on surface turbulent heat flux, atmospheric circulation, and convective precipitation in the northwest portion of an averaged anticyclone.

  7. THE RELIABILITY AND ACCURACY OF THE TRIPLE MEASUREMENTS OF ANALOG PROCESS VARIABLES

    Directory of Open Access Journals (Sweden)

    V. A. Anishchenko

    2017-01-01

    Full Text Available The increase in unit capacity of electric equipment as well as complication of technological processes, devices control and management of the latter in power plants and substations demonstrate the need to improve the reliability and accuracy of measurement information characterizing the state of the objects being managed. The mentioned objective is particularly important for nuclear power plants, where the price of inaccuracy of measurement responsible process variables is particularly high and the error might lead to irreparable consequences. Improving the reliability and accuracy of measurements along with the improvement of the element base is provided by methods of operational validation. These methods are based on the use of information redundancy (structural, topological, temporal. In particular, information redundancy can be achieved by the simultaneous measurement of one analog variable by two (duplication or three devices (triplication i.e., triple redundancy. The problem of operational control of the triple redundant system of measurement of electrical analog variables (currents, voltages, active and reactive power and energy is considered as a special case of signal processing by an orderly sampling on the basis of majority transformation and transformation being close to majority one. Difficulties in monitoring the reliability of measurements are associated with the two tasks. First, one needs to justify the degree of truncation of the distributions of random errors of measurements and allowable residuals of the pairwise differences of the measurement results. The second task consists in formation of the algorithm of joint processing of a set of separate measurements determined as valid. The quality of control is characterized by the reliability, which adopted the synonym of validity, and accuracy of the measuring system. Taken separately, these indicators might lead to opposite results. A compromise solution is therefore proposed

  8. A software framework for developing measurement applications under variable requirements.

    Science.gov (United States)

    Arpaia, Pasquale; Buzio, Marco; Fiscarelli, Lucio; Inglese, Vitaliano

    2012-11-01

    A framework for easily developing software for measurement and test applications under highly and fast-varying requirements is proposed. The framework allows the software quality, in terms of flexibility, usability, and maintainability, to be maximized. Furthermore, the development effort is reduced and finalized, by relieving the test engineer of development details. The framework can be configured for satisfying a large set of measurement applications in a generic field for an industrial test division, a test laboratory, or a research center. As an experimental case study, the design, the implementation, and the assessment inside the application to a measurement scenario of magnet testing at the European Organization for Nuclear Research is reported.

  9. Biophysical characterization of the underappreciated and important relationship between heart rate variability and heart rate.

    Science.gov (United States)

    Monfredi, Oliver; Lyashkov, Alexey E; Johnsen, Anne-Berit; Inada, Shin; Schneider, Heiko; Wang, Ruoxi; Nirmalan, Mahesh; Wisloff, Ulrik; Maltsev, Victor A; Lakatta, Edward G; Zhang, Henggui; Boyett, Mark R

    2014-12-01

    Heart rate (HR) variability (HRV; beat-to-beat changes in the R-wave to R-wave interval) has attracted considerable attention during the past 30+ years (PubMed currently lists >17 000 publications). Clinically, a decrease in HRV is correlated to higher morbidity and mortality in diverse conditions, from heart disease to fetal distress. It is usually attributed to fluctuation in cardiac autonomic nerve activity. We calculated HRV parameters from a variety of cardiac preparations (including humans, living animals, Langendorff-perfused heart, and single sinoatrial nodal cell) in diverse species, combining this with data from previously published articles. We show that regardless of conditions, there is a universal exponential decay-like relationship between HRV and HR. Using 2 biophysical models, we develop a theory for this and confirm that HRV is primarily dependent on HR and cannot be used in any simple way to assess autonomic nerve activity to the heart. We suggest that the correlation between a change in HRV and altered morbidity and mortality is substantially attributable to the concurrent change in HR. This calls for re-evaluation of the findings from many articles that have not adjusted properly or at all for HR differences when comparing HRV in multiple circumstances. © 2014 American Heart Association, Inc.

  10. Variability in response to clopidogrel: how important are pharmacogenetics and drug interactions?

    Science.gov (United States)

    Ma, Terry K W; Lam, Yat-Yin; Tan, Victoria P; Yan, Bryan P

    2011-01-01

    Clopidogrel is a pro-drug which is converted to an active metabolite that selectively blocks ADP-dependent platelet activation and aggregation. The main enzyme responsible for activating clopidogrel is the cytochrome P450 (CYP) isoenzyme CYP2C19, which is polymorphic. There is a growing body of literature showing that carriers of variant CYP2C19 alleles have impaired ability to metabolize clopidogrel (i.e. poor metabolizers), which is associated with decreased inhibition of platelet aggregation and increased cardiovascular risk. Some proton pump inhibitors are also metabolized by the CYP2C19 enzyme and often given together with clopidogrel to reduce gastrointestinal side effects. In particular, omeprazole has been shown to inhibit the CYP-mediated metabolism of clopidogrel, and some studies have shown that the combination was associated with a higher incidence of cardiovascular adverse reactions than clopidogrel given alone. However, a recent randomized controlled trial demonstrated no significant difference in adverse cardiovascular events for patients on the combination of clopidogrel and omeprazole compared with clopidogrel alone. This current review aims to summarize the role of pharmacogenetics and drug interactions in determining variability in response to clopidogrel. PMID:21352268

  11. Disruptive Behavior and Academic Achievement: The Importance of Psychological and Environment Variables

    Directory of Open Access Journals (Sweden)

    Lourenço, Abílio A.

    2010-07-01

    Full Text Available The present investigation aimed to study the impact of self-concept and environment of the classroom in disruptive behaviors, as well as the influence of these behaviors on grades in two state schools in the north of Portugal, through 3 questionnaires (PHCSCS-2, APSA and EDEP to 425 students of the compulsory Portuguese schooling. It was found that with the increase of self-concept and improve the environment of the classroom are less frequent disruptive behaviors, increasing thus the academic achievement of students (Portuguese language and mathematics, which stresses the importance of these constructs in the success school. Educational implications are discussed at these levels of education.

  12. Jarosite in Gale Crater, Mars: The Importance of Temporal and Spatial Variability and Implications for Habitiability

    Science.gov (United States)

    Leveille, R. J.; Oehler, D. Z.; Fairen, A. G.; Clark, B. C.; Niles, P. B.; Blank, J. G.

    2015-01-01

    The Curiosity rover has recently found evidence for small amounts of jarosite, a ferric sulfate, in the Pahrump Hills region at the base of Aeolis Mons (Mount Sharp), Gale crater. While jarosite has been described previously at other locations on Mars, including several sites at Meridiani Planum (explored by the Opportunity rover; and Mawrth Vallis (by remote MRO-CRISM observations; this is the first identification in Gale. Jarosite is interpreted to be a mineral indicator of acidic conditions (pH less than 4; on Earth, it is most commonly found in acid rock-drainage or acid sulfate soil environments. However, jarosite has also been described from a number of terrestrial environments where widespread acidic conditions are not prevalent. As a case study, we describe here an occurrence of sedimentary pyrite nodules that have been variably oxidized in situ to gypsum, schwertmannite, K-/Na-jarosite and iron oxides in a polar desert environment on Devon Island, Nunavut, Canada. Remarkably, these nodules occur in loosely consolidated carbonate sediments, which would have required a higher pH environment at their time of formation and deposition. Thus, acidic conditions may only exist at a small (sub-cm) scale or in a restricted temporal window in an otherwise well-buffered environment. On Devon Island, the jarosite occurs in the most oxidized nodules and is never associated directly with pyrite. Schwertmannite, a metastable iron oxyhydroxysulfate that can form at pH higher than that required for jarosite, occurs in association with partially oxidized pyrite. The paragenetic sequence observed here suggests initial formation of schwertmannite and late-stage precipitation of jarosite in restricted micro-environments, possibly forming via transformation of an amorphous schwertmannite-like phase. While the carbonate environment on Devon Island differs significantly from that of Gale crater, i.e., where we find predominantly basaltic sedimentary rocks, this terrestrial analog

  13. Screening of Catalyst and Important Variable for The Esterification of Acrylic Acid with 2 Ethylhexanol

    Science.gov (United States)

    Ahmad, M. A. A.; Chin, S. Y.

    2017-06-01

    The global demand of 2-ethylhexyl acrylate (2EHA) market has witnessed a significant growth in the past few years and this growth is anticipated to increase in the coming years. 2EHA is one of the basic organic building blocks that mainly used in the production of coatings, adhesives, superabsorbents, thickeners and plastic additives. Homogenous acid-catalysed esterification of acrylic acid (AA) with 2-ethylhexanol (2EH) is commonly used for the production of 2EHA. The homogeneous catalysts such as sulfuric and para-toluene sulfonic acid have resulted the costly and complicated downstream process that generates acidic, corrosive and non-environmental friendly waste. Therefore, it is importance to develop a cheaper process that employing heterogeneous catalysts and alternative raw material from wastewater containing acrylic acid. In this research, the study for the esterification of AA with 2EH catalysed by ion-exchange resin was conducted. The best sulfonic acid functional cation-exchange resin among SK104, SK1B, PK208, PK216, PK228, RCP145, and RCP160 was screened. PK208 outperformed the other resins and it was used subsequently in the parametric studies. The effect of important parameters (initial concentration of acrylic acid (AA), temperature, molar ratio of reactant (AA and 2EH), catalyst loading, and polymerisation inhibitor loading) was studied using 2 factorial design to determine the significant parameters to the esterification. It was found that the initial concentration of AA and temperature were most significantly affecting the esterification of AA with 2EH.

  14. Applications of hybrid measurements with discrete and continuous variables

    DEFF Research Database (Denmark)

    Laghaout, Amine

    . This is what we do for two particular applications of quantum measurements: Bell tests and the amplication of Schrödinger cat states. This project also had an experimental component which was supposed to produce high-fidelity Schrödinger cat states. This goal turned out to be hampered by noise from the laser...

  15. Variability of Capillary Refill Time among Physician Measurements.

    Science.gov (United States)

    Sheridan, David C; Baker, Steven D; Kayser, Susan A; Jones, David; Hansen, Matthew L

    2017-11-01

    The assessment of capillary refill time (CRT) is a common physical examination technique. However, despite its importance and its widespread use, there is little standardization, which can lead to inaccurate assessments. In this article, we assessed how different physicians estimate CRT. We hypothesized that when different physicians are presented with the same recordings of CRT, clinicians will, on average, provide different CRT estimates. Using recordings of different fingertip compressions, physicians assessed and documented when capillary refill had returned to normal. Videos were recorded of the fingertips only, with no other identifying markers or subject characteristics provided. Videos were shown at one-quarter speed to allow time for recognition and response to the capillary refill. The primary outcome was physician estimates of CRT for each video recording. An analysis of variance regression revealed significant differences in physician estimates of CRT when examining the same CRT videos from 34 subjects. Further regression analyses reveal the importance of controlling for the physician that is examining the patient when predicting a patient's CRT. Results indicate that some physicians gave, on average, slower CRT estimates, whereas others gave, on average, faster CRT estimates. Objective approaches and innovations in assessment of capillary refill have the potential to increase the diagnostic accuracy of this important clinical examination finding. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Survival in macaroni penguins and the relative importance of different drivers: individual traits, predation pressure and environmental variability.

    Science.gov (United States)

    Horswill, Catharine; Matthiopoulos, Jason; Green, Jonathan A; Meredith, Michael P; Forcada, Jaume; Peat, Helen; Preston, Mark; Trathan, Phil N; Ratcliffe, Norman

    2014-09-01

    Understanding the demographic response of free-living animal populations to different drivers is the first step towards reliable prediction of population trends. Penguins have exhibited dramatic declines in population size, and many studies have linked this to bottom-up processes altering the abundance of prey species. The effects of individual traits have been considered to a lesser extent, and top-down regulation through predation has been largely overlooked due to the difficulties in empirically measuring this at sea where it usually occurs. For 10 years (2003-2012), macaroni penguins (Eudyptes chrysolophus) were marked with subcutaneous electronic transponder tags and re-encountered using an automated gateway system fitted at the entrance to the colony. We used multistate mark-recapture modelling to identify the different drivers influencing survival rates and a sensitivity analysis to assess their relative importance across different life stages. Survival rates were low and variable during the fledging year (mean = 0·33), increasing to much higher levels from age 1 onwards (mean = 0·89). We show that survival of macaroni penguins is driven by a combination of individual quality, top-down predation pressure and bottom-up environmental forces. The relative importance of these covariates was age specific. During the fledging year, survival rates were most sensitive to top-down predation pressure, followed by individual fledging mass, and finally bottom-up environmental effects. In contrast, birds older than 1 year showed a similar response to bottom-up environmental effects and top-down predation pressure. We infer from our results that macaroni penguins will most likely be negatively impacted by an increase in the local population size of giant petrels. Furthermore, this population is, at least in the short term, likely to be positively influenced by local warming. More broadly, our results highlight the importance of considering multiple causal effects across

  17. Canonical Measure of Correlation (CMC) and Canonical Measure of Distance (CMD) between sets of data. Part 3. Variable selection in classification.

    Science.gov (United States)

    Ballabio, Davide; Consonni, Viviana; Mauri, Andrea; Todeschini, Roberto

    2010-01-11

    In multivariate regression and classification issues variable selection is an important procedure used to select an optimal subset of variables with the aim of producing more parsimonious and eventually more predictive models. Variable selection is often necessary when dealing with methodologies that produce thousands of variables, such as Quantitative Structure-Activity Relationships (QSARs) and highly dimensional analytical procedures. In this paper a novel method for variable selection for classification purposes is introduced. This method exploits the recently proposed Canonical Measure of Correlation between two sets of variables (CMC index). The CMC index is in this case calculated for two specific sets of variables, the former being comprised of the independent variables and the latter of the unfolded class matrix. The CMC values, calculated by considering one variable at a time, can be sorted and a ranking of the variables on the basis of their class discrimination capabilities results. Alternatively, CMC index can be calculated for all the possible combinations of variables and the variable subset with the maximal CMC can be selected, but this procedure is computationally more demanding and classification performance of the selected subset is not always the best one. The effectiveness of the CMC index in selecting variables with discriminative ability was compared with that of other well-known strategies for variable selection, such as the Wilks' Lambda, the VIP index based on the Partial Least Squares-Discriminant Analysis, and the selection provided by classification trees. A variable Forward Selection based on the CMC index was finally used in conjunction of Linear Discriminant Analysis. This approach was tested on several chemical data sets. Obtained results were encouraging.

  18. Landsat Imagery Spectral Trajectories—Important Variables for Spatially Predicting the Risks of Bark Beetle Disturbance

    Directory of Open Access Journals (Sweden)

    Martin Hais

    2016-08-01

    Full Text Available Tree mortality caused by bark beetle infestation has significant effects on the ecology and value of both natural and commercial forests. Therefore, prediction of bark beetle infestations is critical in forest management. Existing predictive models, however, rarely consider the influence of long-term stressors on forest susceptibility to bark beetle infestation. In this study we introduce pre-disturbance spectral trajectories from Landsat Thematic Mapper (TM imagery as an indicator of long-term stress into models of bark beetle infestation together with commonly used environmental predictors. Observations for this study come from forests in the central part of the Šumava Mountains, in the border region between the Czech Republic and Germany, Central Europe. The areas of bark beetle-infested forest were delineated from aerial photographs taken in 1991 and in every year from 1994 to 2000. The environmental predictors represent forest stand attributes (e.g., tree density and distance to the infested forest from previous year and common abiotic factors, such as topography, climate, geology, and soil. Pre-disturbance spectral trajectories were defined by the linear regression slope of Tasseled Cap components (Wetness, Brightness and Greenness calculated from a time series of 16 Landsat TM images across years from 1984 until one year before the bark beetle infestation. Using logistic regression and multimodel inference, we calculated predictive models separately for each single year from 1994 to 2000 to account for a possible shift in importance of individual predictors during disturbance. Inclusion of two pre-disturbance spectral trajectories (Wetness slope and Brightness slope significantly improved predictive ability of bark beetle infestation models. Wetness slope had the greatest predictive power, even relative to environmental predictors, and was relatively stable in its power over the years. Brightness slope improved the model only in the

  19. Predicting Local Dengue Transmission in Guangzhou, China, through the Influence of Imported Cases, Mosquito Density and Climate Variability

    Science.gov (United States)

    Sang, Shaowei; Yin, Wenwu; Bi, Peng; Zhang, Honglong; Wang, Chenggang; Liu, Xiaobo; Chen, Bin; Yang, Weizhong; Liu, Qiyong

    2014-01-01

    Introduction Each year there are approximately 390 million dengue infections worldwide. Weather variables have a significant impact on the transmission of Dengue Fever (DF), a mosquito borne viral disease. DF in mainland China is characterized as an imported disease. Hence it is necessary to explore the roles of imported cases, mosquito density and climate variability in dengue transmission in China. The study was to identify the relationship between dengue occurrence and possible risk factors and to develop a predicting model for dengue’s control and prevention purpose. Methodology and Principal Findings Three traditional suburbs and one district with an international airport in Guangzhou city were selected as the study areas. Autocorrelation and cross-correlation analysis were used to perform univariate analysis to identify possible risk factors, with relevant lagged effects, associated with local dengue cases. Principal component analysis (PCA) was applied to extract principal components and PCA score was used to represent the original variables to reduce multi-collinearity. Combining the univariate analysis and prior knowledge, time-series Poisson regression analysis was conducted to quantify the relationship between weather variables, Breteau Index, imported DF cases and the local dengue transmission in Guangzhou, China. The goodness-of-fit of the constructed model was determined by pseudo-R2, Akaike information criterion (AIC) and residual test. There were a total of 707 notified local DF cases from March 2006 to December 2012, with a seasonal distribution from August to November. There were a total of 65 notified imported DF cases from 20 countries, with forty-six cases (70.8%) imported from Southeast Asia. The model showed that local DF cases were positively associated with mosquito density, imported cases, temperature, precipitation, vapour pressure and minimum relative humidity, whilst being negatively associated with air pressure, with different time

  20. Predicting local dengue transmission in Guangzhou, China, through the influence of imported cases, mosquito density and climate variability.

    Directory of Open Access Journals (Sweden)

    Shaowei Sang

    Full Text Available Each year there are approximately 390 million dengue infections worldwide. Weather variables have a significant impact on the transmission of Dengue Fever (DF, a mosquito borne viral disease. DF in mainland China is characterized as an imported disease. Hence it is necessary to explore the roles of imported cases, mosquito density and climate variability in dengue transmission in China. The study was to identify the relationship between dengue occurrence and possible risk factors and to develop a predicting model for dengue's control and prevention purpose.Three traditional suburbs and one district with an international airport in Guangzhou city were selected as the study areas. Autocorrelation and cross-correlation analysis were used to perform univariate analysis to identify possible risk factors, with relevant lagged effects, associated with local dengue cases. Principal component analysis (PCA was applied to extract principal components and PCA score was used to represent the original variables to reduce multi-collinearity. Combining the univariate analysis and prior knowledge, time-series Poisson regression analysis was conducted to quantify the relationship between weather variables, Breteau Index, imported DF cases and the local dengue transmission in Guangzhou, China. The goodness-of-fit of the constructed model was determined by pseudo-R2, Akaike information criterion (AIC and residual test. There were a total of 707 notified local DF cases from March 2006 to December 2012, with a seasonal distribution from August to November. There were a total of 65 notified imported DF cases from 20 countries, with forty-six cases (70.8% imported from Southeast Asia. The model showed that local DF cases were positively associated with mosquito density, imported cases, temperature, precipitation, vapour pressure and minimum relative humidity, whilst being negatively associated with air pressure, with different time lags.Imported DF cases and mosquito

  1. Predicting local dengue transmission in Guangzhou, China, through the influence of imported cases, mosquito density and climate variability.

    Science.gov (United States)

    Sang, Shaowei; Yin, Wenwu; Bi, Peng; Zhang, Honglong; Wang, Chenggang; Liu, Xiaobo; Chen, Bin; Yang, Weizhong; Liu, Qiyong

    2014-01-01

    Each year there are approximately 390 million dengue infections worldwide. Weather variables have a significant impact on the transmission of Dengue Fever (DF), a mosquito borne viral disease. DF in mainland China is characterized as an imported disease. Hence it is necessary to explore the roles of imported cases, mosquito density and climate variability in dengue transmission in China. The study was to identify the relationship between dengue occurrence and possible risk factors and to develop a predicting model for dengue's control and prevention purpose. Three traditional suburbs and one district with an international airport in Guangzhou city were selected as the study areas. Autocorrelation and cross-correlation analysis were used to perform univariate analysis to identify possible risk factors, with relevant lagged effects, associated with local dengue cases. Principal component analysis (PCA) was applied to extract principal components and PCA score was used to represent the original variables to reduce multi-collinearity. Combining the univariate analysis and prior knowledge, time-series Poisson regression analysis was conducted to quantify the relationship between weather variables, Breteau Index, imported DF cases and the local dengue transmission in Guangzhou, China. The goodness-of-fit of the constructed model was determined by pseudo-R2, Akaike information criterion (AIC) and residual test. There were a total of 707 notified local DF cases from March 2006 to December 2012, with a seasonal distribution from August to November. There were a total of 65 notified imported DF cases from 20 countries, with forty-six cases (70.8%) imported from Southeast Asia. The model showed that local DF cases were positively associated with mosquito density, imported cases, temperature, precipitation, vapour pressure and minimum relative humidity, whilst being negatively associated with air pressure, with different time lags. Imported DF cases and mosquito density play a

  2. Systematic analysis of measurement variability in lung cancer with multidetector computed tomography.

    Science.gov (United States)

    Jiang, Binghu; Zhou, Dan; Sun, Yujie; Wang, Jichen

    2017-01-01

    To systematically analyze the nature of measurement variability in lung cancer with multidetector computed tomography (CT) scans. Multidetector CT scans of 67 lung cancer patients were analyzed. Unidimensional (Response Evaluation Criteria in Solid Tumor criteria), bidimensional (World Health Organization criteria), and volumetric measurements were performed independently by ten radiologists and were repeated after at least 5 months. Repeatability and reproducibility measurement variations were estimated by analyzing reliability, agreement, variation coefficient, and misclassification statistically. The relationship of measurement variability with various sources was also analyzed. Analyses of 69 lung tumors with an average size of 1.1-12.1 cm (mean 4.3 cm) indicated that volumetric technique had the minimum measurement variability compared to the unidimensional or bidimensional technique. Tumor characteristics (object effect) could be the primary factor to influence measurement variability while the effect of raters (subjective effect) was faint. Segmentation and size in tumor characteristics were associated with measurement variability, and some mathematical function was established between the volumetric variability and tumor size. Volumetric technique has the minimum variability in measuring lung cancer, and measurement variability is associated with tumor size by nonlinear mathematical function.

  3. Enceladus Plume Morphology and Variability from UVIS Measurements

    Science.gov (United States)

    Hansen, Candice; Esposito, Larry; Colwell, Josh; Hendrix, Amanda; Portyankina, Ganna

    2017-10-01

    The Ultraviolet Imaging Spectrograph (UVIS) on the Cassini spacecraft has been observing Enceladus’ plume and its effect on the Saturnian environment since 2004. One solar and 7 stellar occultations have been observed between 2005 and 2017. On 27 March 2017 epsilon Canis Majoris (CMa) passed behind the plume of water vapor spewing from Enceladus’ tiger stripe fissures. With this occultation we have 6 cuts through the plume at a variety of orientations over 12 years. Following our standard procedure the column density along the line of sight from Enceladus to the star was determined and the water flux calculated [1]. The mean anomaly was 131, well away from the dust flux peak associated with Enceladus at an orbital longitude near apoapsis [2]. We find that the water vapor flux was ~160 kg/sec (this number will be refined when the final reconstructed trajectory is available). That puts it “in family” with the other occultations, with values that cluster around 200 kg/sec. It is at the low end, which may be consistent with the drop in particle output observed over the last decade [3]. UVIS results show that the supersonic collimated gas jets imbedded in the plume are the likely source of the variability in dust output [4], rather than overall flux from the tiger stripes. An occultation of epsilon Orionis was observed on 11 March 2016 when Enceladus was at a mean anomaly of 208. Although the bulk flux changed little the amount of water vapor coming from the Baghdad I supersonic jet increased by 25% relative to 2011. The Baghdad I jet was observed again in the 2017 epsilon CMa occultation, and the column density is half that of 2016, further bolstering the conclusion that the gas jets change output as a function of orbital longitude. UVIS results describing gas flux, jets, and general structure of the plume, the observables above the surface, are key to testing hypotheses for what is driving Enceladus’ eruptive activity below the surface. [1] Hansen, C. J. et

  4. Estimation of intersubject variability of cerebral blood flow measurements using MRI and positron emission tomography

    DEFF Research Database (Denmark)

    Henriksen, Otto Mølby; Larsson, Henrik B W; Hansen, Adam E

    2012-01-01

    PURPOSE: To investigate the within and between subject variability of quantitative cerebral blood flow (CBF) measurements in normal subjects using various MRI techniques and positron emission tomography (PET). MATERIALS AND METHODS: Repeated CBF measurements were performed in 17 healthy, young...

  5. Measuring the Evolutionarily Important Goals of Situations: Situational Affordances for Adaptive Problems

    National Research Council Canada - National Science Library

    Brown, Nicolas A; Neel, Rebecca; Sherman, Ryne A

    2015-01-01

    .... This article introduces the Situational Affordances for Adaptive Problems (SAAP), a measure of situation characteristics that promotes or prevents the achievement of these evolutionarily important goals...

  6. Core-temperature sensor ingestion timing and measurement variability.

    Science.gov (United States)

    Domitrovich, Joseph W; Cuddy, John S; Ruby, Brent C

    2010-01-01

    Telemetric core-temperature monitoring is becoming more widely used as a noninvasive means of monitoring core temperature during athletic events. To determine the effects of sensor ingestion timing on serial measures of core temperature during continuous exercise. Crossover study. Outdoor dirt track at an average ambient temperature of 4.4°C ± 4.1°C and relative humidity of 74.1% ± 11.0%. Seven healthy, active participants (3 men, 4 women; age  =  27.0 ± 7.5 years, height  =  172.9 ± 6.8 cm, body mass  =  67.5 ± 6.1 kg, percentage body fat  =  12.7% ± 6.9%, peak oxygen uptake [Vo(2peak)]  =  54.4 ± 6.9 mL•kg⁻¹•min⁻¹) completed the study. Participants completed a 45-minute exercise trial at approximately 70% Vo(2peak). They consumed core-temperature sensors at 24 hours (P1) and 40 minutes (P2) before exercise. Core temperature was recorded continuously (1-minute intervals) using a wireless data logger worn by the participants. All data were analyzed using a 2-way repeated-measures analysis of variance (trial × time), Pearson product moment correlation, and Bland-Altman plot. Fifteen comparisons were made between P1 and P2. The main effect of time indicated an increase in core temperature compared with the initial temperature. However, we did not find a main effect for trial or a trial × time interaction, indicating no differences in core temperature between the sensors (P1  =  38.3°C ± 0.2°C, P2  =  38.3°C ± 0.4°C). We found no differences in the temperature recordings between the 2 sensors. These results suggest that assumed sensor location (upper or lower gastrointestinal tract) does not appreciably alter the transmission of reliable and repeatable measures of core temperature during continuous running in the cold.

  7. Instruments for Measuring Nursing Practice and Other Health Care Variables: Volume I [and] Volume 2.

    Science.gov (United States)

    Ward, Mary Jane, Ed.; Lindeman, Carol Ann, Ed.

    This two-volume compilation classifies, describes, and critiques 159 clinical nursing instruments; 140 which measure psychosocial variables, 19 which measure physiological variables. Instruments are in various formats: paper and pencil tests, questionnaires, interview schedules, observation guides, rating scales, and mechanical devices such as…

  8. Evaluation for Intensity of Stress in Lesson using Heart Rate Variability Detected by Simultaneously Measurement

    Science.gov (United States)

    Horiguchi, Ayaka; Takatsu, Hiroaki; Ohno, Wataru; Ozeki, Osamu

    We studied the evaluation for the intensity of stress of students in lesson using heart rate variability. Heart rate of many students were measured simultaneously by developed portable measurement systems. Heart rate variability data suggests that many students have more stress in normal dictation lesson then video lesson using difficult subject.

  9. Decreased Heart Rate Variability in HIV Positive Patients Receiving Antiretroviral Therapy: Importance of Blood Glucose and Cholesterol

    DEFF Research Database (Denmark)

    Askgaard, Gro; Kristoffersen, Ulrik Sloth; Mehlsen, Jesper

    2011-01-01

    received medication for hypertension. Following a 10 min resting period a 15 min ECG recording was performed. Heart-rate variability (HRV) analysis was performed in accordance with current guidelines and data reported as mean [interquartile range]. RESULTS: Mean normal-to-normal (NN) and total HRV measured...... as standard deviation of normal-to-normal (SDNN) was lower in HIV patients compared to controls (905 vs. 982 ms; p

  10. Tack Measurements of Prepreg Tape at Variable Temperature and Humidity

    Science.gov (United States)

    Wohl, Christopher; Palmieri, Frank L.; Forghani, Alireza; Hickmott, Curtis; Bedayat, Houman; Coxon, Brian; Poursartip, Anoush; Grimsley, Brian

    2017-01-01

    NASA’s Advanced Composites Project has established the goal of achieving a 30 percent reduction in the timeline for certification of primary composite structures for application on commercial aircraft. Prepreg tack is one of several critical parameters affecting composite manufacturing by automated fiber placement (AFP). Tack plays a central role in the prevention of wrinkles and puckers that can occur during AFP, thus knowledge of tack variation arising from a myriad of manufacturing and environmental conditions is imperative for the prediction of defects during AFP. A full design of experiments was performed to experimentally characterize tack on 0.25-inch slit-tape tow IM7/8552-1 prepreg using probe tack testing. Several process parameters (contact force, contact time, retraction speed, and probe diameter) as well as environmental parameters (temperature and humidity) were varied such that the entire parameter space could be efficiently evaluated. Mid-point experimental conditions (i.e., parameters not at either extrema) were included to enable prediction of curvature in relationships and repeat measurements were performed to characterize experimental error. Collectively, these experiments enable determination of primary dependencies as well as multi-parameter relationships. Slit-tape tow samples were mounted to the bottom plate of a rheometer parallel plate fixture using a jig to prevent modification of the active area to be interrogated with the top plate, a polished stainless steel probe, during tack testing. The probe surface was slowly brought into contact with the pre-preg surface until a pre-determined normal force was achieved (2-30 newtons). After a specified dwell time (0.02-10 seconds), during which the probe substrate interaction was maintained under displacement control, the probe was retracted from the surface (0.1-50 millimeters per second). Initial results indicated a clear dependence of tack strength on several parameters, with a particularly

  11. Climate variables explain neutral and adaptive variation within salmonid metapopulations: The importance of replication in landscape genetics

    Science.gov (United States)

    Hand, Brian K; Muhlfeld, Clint C.; Wade, Alisa A.; Kovach, Ryan; Whited, Diane C.; Narum, Shawn R.; Matala, Andrew P; Ackerman, Michael W.; Garner, B. A.; Kimball, John S; Stanford, Jack A.; Luikart, Gordon

    2016-01-01

    Understanding how environmental variation influences population genetic structure is important for conservation management because it can reveal how human stressors influence population connectivity, genetic diversity and persistence. We used riverscape genetics modelling to assess whether climatic and habitat variables were related to neutral and adaptive patterns of genetic differentiation (population-specific and pairwise FST) within five metapopulations (79 populations, 4583 individuals) of steelhead trout (Oncorhynchus mykiss) in the Columbia River Basin, USA. Using 151 putatively neutral and 29 candidate adaptive SNP loci, we found that climate-related variables (winter precipitation, summer maximum temperature, winter highest 5% flow events and summer mean flow) best explained neutral and adaptive patterns of genetic differentiation within metapopulations, suggesting that climatic variation likely influences both demography (neutral variation) and local adaptation (adaptive variation). However, we did not observe consistent relationships between climate variables and FST across all metapopulations, underscoring the need for replication when extrapolating results from one scale to another (e.g. basin-wide to the metapopulation scale). Sensitivity analysis (leave-one-population-out) revealed consistent relationships between climate variables and FST within three metapopulations; however, these patterns were not consistent in two metapopulations likely due to small sample sizes (N = 10). These results provide correlative evidence that climatic variation has shaped the genetic structure of steelhead populations and highlight the need for replication and sensitivity analyses in land and riverscape genetics.

  12. Repeatability of gait pattern variables measured by use of extremity-mounted inertial measurement units in nonlame horses during trotting.

    Science.gov (United States)

    Cruz, Antonio M; Maninchedda, Ugo E; Burger, Dominik; Wanda, Sabine; Vidondo, Beatriz

    2017-09-01

    OBJECTIVE To determine repeatability of gait variables measured by use of extremity-mounted inertial measurement units (IMUs) in nonlame horses during trotting under controlled conditions of treadmill exercise. ANIMALS 10 horses. PROCEDURES Six IMUs were strapped to the metacarpal, metatarsal, and distal tibial regions of each horse. Data were collected in a standardized manner (3 measurements/d on 3 d/wk over a 3-week period) while each horse was trotted on a treadmill. Every measurement consisted of a minimum of 20 strides from which a minimum of 10 strides was selected for analysis. Spatial and temporal variables were derived from the IMUs. Repeatability coefficients based on the within-subject SD were computed for each gait analysis variable at each week. RESULTS Most of the temporal and spatial variables had high repeatability (repeatability coefficients variables, specifically the symmetry variables (which were calculated from other variables), had somewhat higher repeatability coefficients (ie, lower repeatability) only in the last week. CONCLUSIONS AND CLINICAL RELEVANCE With the exceptions of some symmetry variables, which may reflect individual variations during movement, the extremity-mounted IMUs provided data with high repeatability for nonlame horses trotting under controlled conditions of treadmill exercise. Repeatability was achieved for each instrumented limb segment with regard to the spatial relationship between 2 adjacent segments (joint angles) and the temporal relationship among all segments (limb phasing). Extremity-mounted IMUs could have the potential to become a method for gait analysis in horses.

  13. The importance of pre-measurements of wellheing and achievement for students' current wellheing

    NARCIS (Netherlands)

    Van Petegem, Karen; Creemers, Bert; Aelterman, Antonia; Rosseel, Yves

    2008-01-01

    Educational effectiveness research focuses not only on cognitive output but also on affective student outcomes. Student wellbeing has to be addressed as an important output variable of the educational process. The focus in this study is on student wellbeing at the end of Grade 10 and its

  14. Capturing Dynamics of Biased Attention: Are New Attention Variability Measures the Way Forward?

    Directory of Open Access Journals (Sweden)

    Anne-Wil Kruijt

    Full Text Available New indices, calculated on data from the widely used Dot Probe Task, were recently proposed to capture variability in biased attention allocation. We observed that it remains unclear which data pattern is meant to be indicative of dynamic bias and thus to be captured by these indices. Moreover, we hypothesized that the new indices are sensitive to SD differences at the response time (RT level in the absence of bias.Randomly generated datasets were analyzed to assess properties of the Attention Bias Variability (ABV and Trial Level Bias Score (TL-BS indices. Sensitivity to creating differences in 1 RT standard deviation, 2 mean RT, and 3 bias magnitude were assessed. In addition, two possible definitions of dynamic attention bias were explored by creating differences in 4 frequency of bias switching, and 5 bias magnitude in the presence of constant switching.ABV and TL-BS indices were found highly sensitive to increasing SD at the response time level, insensitive to increasing bias, linearly sensitive to increasing bias magnitude in the presence of bias switches, and non-linearly sensitive to increasing the frequency of bias switches. The ABV index was also found responsive to increasing mean response times in the absence of bias.Recently proposed DPT derived variability indices cannot uncouple measurement error from bias variability. Significant group differences may be observed even if there is no bias present in any individual dataset. This renders the new indices in their current form unfit for empirical purposes. Our discussion focuses on fostering debate and ideas for new research to validate the potentially very important notion of biased attention being dynamic.

  15. Tsunami waveform inversion for sea surface displacement following the 2011 Tohoku Earthquake: Importance of dispersion and variable rupture velocity

    Science.gov (United States)

    Cummins, P. R.; Hossen, M. J.; Dettmer, J.; Baba, T.

    2015-12-01

    This presentation considers the importance of model parametrization, including dispersion, source kinematics and source discretization, in tsunami source inversion. We implement single and multiple time window methods for dispersive and non-dispersive wave propagation to estimate source models for the tsunami generated by the 2011 Tohoku-oki earthquake. Our source model is described by sea surface displacement instead of fault slip, since sea surface displacement accounts for various tsunami generation mechanisms in addition to fault slip. The results show that tsunami source models can strongly depend on such model choices, particularly when high-quality, open-ocean tsunami waveform data are available. We carry out several synthetic inversion tests to validate the method and assess the impact of parametrization including dispersion and variable rupture velocity in data predictions on the inversion results. Although each of these effects have been considered separately in previous studies, we show that it is important to consider them together in order to obtain more meaningful inversion results. Our results suggest that the discretization of the source, the use of dispersive waves, and accounting for source kinematics are all important factors in tsunami source inversion of large events such as the Tohoku-oki earthquake, particularly when an extensive set of high quality tsunami waveform recordings are available. For the Tohoku event, a dispersive model with variable rupture velocity results in a profound improvement in waveform fits that justify the higher source complexity and provide a more realistic source model.

  16. The Impact of Resonance Frequency Breathing on Measures of Heart Rate Variability, Blood Pressure, and Mood

    Directory of Open Access Journals (Sweden)

    Patrick R. Steffen

    2017-08-01

    Full Text Available Heart rate variability biofeedback (HRVB significantly improves heart rate variability (HRV. Breathing at resonance frequency (RF, approximately 6 breaths/min constitutes a key part of HRVB training and is hypothesized to be a pathway through which biofeedback improves HRV. No studies to date, however, have experimentally examined whether RF breathing impacts measures of HRV. The present study addressed this question by comparing three groups: the RF group breathed at their determined RF for 15 min; the RF + 1 group breathed at 1 breath/min higher than their determined RF for 15 min; and the third group sat quietly for 15 min. After this 15-min period, all groups participated in the Paced Auditory Serial Addition Task (PASAT for 8 min, and then sat quietly during a 10-min recovery period. HRV, blood pressure, and mood were measured throughout the experiment. Groups were not significantly different on any of the measures at baseline. After the breathing exercise, the RF group reported higher positive mood than the other two groups and a significantly higher LF/HF HRV ratio relative to the control group, a key goal in HRVB training (p < 0.05. Additionally, the RF group showed lower systolic blood pressure during the PASAT and during the recovery period relative to the control group, with the RF + 1 group not being significantly different from either group (p < 0.05. Overall, RF breathing appears to play an important role in the positive effect HRVB has on measures of HRV.

  17. Evaluation of the Wind Flow Variability Using Scanning Doppler Lidar Measurements

    Science.gov (United States)

    Sand, S. C.; Pichugina, Y. L.; Brewer, A.

    2016-12-01

    Better understanding of the wind flow variability at the heights of the modern turbines is essential to accurately assess of generated wind power and efficient turbine operations. Nowadays the wind energy industry often utilizes scanning Doppler lidar to measure wind-speed profiles at high spatial and temporal resolution.The study presents wind flow features captured by scanning Doppler lidars during the second Wind Forecast and Improvement Project (WFIP 2) sponsored by the Department of Energy (DOE) and National Oceanic and Atmospheric Administration (NOAA). This 18-month long experiment in the Columbia River Basin aims to improve model wind forecasts complicated by mountain terrain, coastal effects, and numerous wind farms.To provide a comprehensive dataset to use for characterizing and predicting meteorological phenomena important to Wind Energy, NOAA deployed scanning, pulsed Doppler lidars to two sites in Oregon, one at Wasco, located upstream of all wind farms relative to the predominant westerly flow in the region, and one at Arlington, located in the middle of several wind farms.In this presentation we will describe lidar scanning patterns capable of providing data in conical, or vertical-slice modes. These individual scans were processed to obtain 15-min averaged profiles of wind speed and direction in real time. Visualization of these profiles as time-height cross sections allows us to analyze variability of these parameters with height, time and location, and reveal periods of rapid changes (ramp events). Examples of wind flow variability between two sites of lidar measurements along with examples of reduced wind velocity downwind of operating turbines (wakes) will be presented.

  18. FIRE: an SPSS program for variable selection in multiple linear regression analysis via the relative importance of predictors.

    Science.gov (United States)

    Lorenzo-Seva, Urbano; Ferrando, Pere J

    2011-03-01

    We provide an SPSS program that implements currently recommended techniques and recent developments for selecting variables in multiple linear regression analysis via the relative importance of predictors. The approach consists of: (1) optimally splitting the data for cross-validation, (2) selecting the final set of predictors to be retained in the equation regression, and (3) assessing the behavior of the chosen model using standard indices and procedures. The SPSS syntax, a short manual, and data files related to this article are available as supplemental materials from brm.psychonomic-journals.org/content/supplemental.

  19. The Importance of and the Complexities Associated With Measuring Continuity of Care During Resident Training: Possible Solutions Do Exist.

    Science.gov (United States)

    Carney, Patricia A; Conry, Colleen M; Mitchell, Karen B; Ericson, Annie; Dickinson, W Perry; Martin, James C; Carek, Peter J; Douglass, Alan B; Eiff, M Patrice

    2016-04-01

    Evolutions in care delivery toward the patient-centered medical home have influenced important aspects of care continuity. Primary responsibility for a panel of continuity patients is a foundational requirement in family medicine residencies. In this paper we characterize challenges in measuring continuity of care in residency training in this new era of primary care. We synthesized the literature and analyzed information from key informant interviews and group discussions with residency faculty and staff to identify the challenges and possible solutions for measuring continuity of care during family medicine training. We specifically focused on measuring interpersonal continuity at the patient level, resident level, and health care team level. Challenges identified in accurately measuring interpersonal continuity of care during residency training include: (1) variability in empanelment approaches for all patients, (2) scheduling complexity in different types of visits, (3) variability in ability to attain continuity counts at the level of the resident, and (4) shifting make-up of health care teams, especially in residency training. Possible solutions for each challenge are presented. Philosophical issues related to continuity are discussed, including whether true continuity can be achieved during residency training and whether qualitative rather than quantitative measures of continuity are better suited to residencies. Measuring continuity of care in residency training is challenging but possible, though improvements in precision and assessment of the comprehensive nature of the relationships are needed. Definitions of continuity during training and the role continuity measurement plays in residency need further study.

  20. Observer variability of lung function measurements in 2-6-yr-old children

    DEFF Research Database (Denmark)

    Klug, B; Nielsen, K G; Bisgaard, H

    2000-01-01

    The aim of this study was to assess the within-observer and between-observer variability of lung function measurements in children aged 2-6 yrs. Two observers examined 22 asthmatic children independently according to a predefined protocol. Each observer obtained duplicate measurements of respirat......The aim of this study was to assess the within-observer and between-observer variability of lung function measurements in children aged 2-6 yrs. Two observers examined 22 asthmatic children independently according to a predefined protocol. Each observer obtained duplicate measurements...... by the interrupter technique measurements in young children are subject to influence by the observer, and the random variability between observers appears to be particularly great for respiratory resistance assessed by the interrupter technique. The authors suggest that the between-observer variability should...... be investigated when evaluating novel methods for testing lung function....

  1. Finite-size analysis of measurement-device-independent quantum cryptography with continuous variables

    Science.gov (United States)

    Papanastasiou, Panagiotis; Ottaviani, Carlo; Pirandola, Stefano

    2017-10-01

    We study the impact of finite-size effects on the key rate of continuous-variable (CV) measurement-device-independent (MDI) quantum key distribution (QKD), considering two-mode Gaussian attacks. Inspired by the parameter estimation technique developed in by Ruppert et al. [Phys. Rev. A 90, 062310 (2014), 10.1103/PhysRevA.90.062310], we adapt it to study CV-MDI-QKD and, assuming realistic experimental conditions, we analyze the impact of finite-size effects on the key rate. We find that the performance of the protocol approaches the ideal one, increasing the block size, and, most importantly, that blocks between 106 and 109 data points may provide key rates ˜10-2 bit/use over metropolitan distances.

  2. Measuring the chemical and cytotoxic variability of commercially available kava (Piper methysticum G. Forster.

    Directory of Open Access Journals (Sweden)

    Amanda C Martin

    Full Text Available Formerly used world-wide as a popular botanical medicine to reduce anxiety, reports of hepatotoxicity linked to consuming kava extracts in the late 1990s have resulted in global restrictions on kava use and have hindered kava-related research. Despite its presence on the United States Food and Drug Administration consumer advisory list for the past decade, export data from kava producing countries implies that US kava imports, which are not publicly reported, are both increasing and of a fairly high volume. We have measured the variability in extract chemical composition and cytotoxicity towards human lung adenocarcinoma A549 cancer cells of 25 commercially available kava products. Results reveal a high level of variation in chemical content and cytotoxicity of currently available kava products. As public interest and use of kava products continues to increase in the United States, efforts to characterize products and expedite research of this potentially useful botanical medicine are necessary.

  3. Risk Importance Measures in the Designand Operation of Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Vrbanic I.; Samanta P.; Basic, I

    2017-10-31

    This monograph presents and discusses risk importance measures as quantified by the probabilistic risk assessment (PRA) models of nuclear power plants (NPPs) developed according to the current standards and practices. Usually, PRA tools calculate risk importance measures related to a single ?basic event? representing particular failure mode. This is, then, reflected in many current PRA applications. The monograph focuses on the concept of ?component-level? importance measures that take into account different failure modes of the component including common-cause failures (CCFs). In opening sections the roleof risk assessment in safety analysis of an NPP is introduced and discussion given of ?traditional?, mainly deterministic, design principles which have been established to assign a level of importance to a particular system, structure or component. This is followed by an overview of main risk importance measures for risk increase and risk decrease from current PRAs. Basic relations which exist among the measures are shown. Some of the current practical applications of risk importancemeasures from the field of NPP design, operation and regulation are discussed. The core of the monograph provides a discussion on theoreticalbackground and practical aspects of main risk importance measures at the level of ?component? as modeled in a PRA, starting from the simplest case, single basic event, and going toward more complexcases with multiple basic events and involvements in CCF groups. The intent is to express the component-level importance measures via theimportance measures and probabilities of the underlying single basic events, which are the inputs readily available from a PRA model andits results. Formulas are derived and discussed for some typical cases. The formulas and their results are demonstrated through some practicalexamples, done by means of a simplified PRA model developed in and run by RiskSpectrum? tool, which are presented in the appendices. The

  4. Authentic early experience in Medical Education: a socio-cultural analysis identifying important variables in learning interactions within workplaces.

    Science.gov (United States)

    Yardley, Sarah; Brosnan, Caragh; Richardson, Jane; Hays, Richard

    2013-12-01

    This paper addresses the question 'what are the variables influencing social interactions and learning during Authentic Early Experience (AEE)?' AEE is a complex educational intervention for new medical students. Following critique of the existing literature, multiple qualitative methods were used to create a study framework conceptually orientated to a socio-cultural perspective. Study participants were recruited from three groups at one UK medical school: students, workplace supervisors, and medical school faculty. A series of intersecting spectra identified in the data describe dyadic variables that make explicit the parameters within which social interactions are conducted in this setting. Four of the spectra describe social processes related to being in workplaces and developing the ability to manage interactions during authentic early experiences. These are: (1) legitimacy expressed through invited participation or exclusion; (2) finding a role-a spectrum from student identity to doctor mindset; (3) personal perspectives and discomfort in transition from lay to medical; and, (4) taking responsibility for 'risk'-moving from aversion to management through graded progression of responsibility. Four further spectra describe educational consequences of social interactions. These spectra identify how the reality of learning is shaped through social interactions and are (1) generic-specific objectives, (2) parallel-integrated-learning, (3) context specific-transferable learning and (4) performing or simulating-reality. Attention to these variables is important if educators are to maximise constructive learning from AEE. Application of each of the spectra could assist workplace supervisors to maximise the positive learning potential of specific workplaces.

  5. Effects of variability of meteorological measures on soil temperature in permafrost regions

    OpenAIRE

    Beer, Christian; Porada, Philipp; Ekici, Altug; Brakebusch, Matthias

    2016-01-01

    To clarify effects of the variability of meteorological measures and their extreme events on topsoil and subsoil temperature in permafrost regions, an artificially manipulated climate dataset has been used for process-oriented model experiments. Climate variability mainly impacts snow depth, and the cover and thermal diffusivity of lichens and bryophytes. The latter effect is of opposite direction in summer and winter. These impacts of climate variability on insulating layers together substan...

  6. Examining Parallelism of Sets of Psychometric Measures Using Latent Variable Modeling

    Science.gov (United States)

    Raykov, Tenko; Patelis, Thanos; Marcoulides, George A.

    2011-01-01

    A latent variable modeling approach that can be used to examine whether several psychometric tests are parallel is discussed. The method consists of sequentially testing the properties of parallel measures via a corresponding relaxation of parameter constraints in a saturated model or an appropriately constructed latent variable model. The…

  7. Guide to the measurement of tree characteristics important to the quality classification for young hardwood trees

    Science.gov (United States)

    David L. Sonderman

    1979-01-01

    A procedure is shown for measuring external tree characteristics that are important in determining the current and future quality of young hardwood trees. This guide supplements a precious study which describes the quality classification system for young hardwood trees

  8. Measuring pH variability using an experimental sensor on an underwater glider

    Science.gov (United States)

    Hemming, Michael P.; Kaiser, Jan; Heywood, Karen J.; Bakker, Dorothee C. E.; Boutin, Jacqueline; Shitashima, Kiminori; Lee, Gareth; Legge, Oliver; Onken, Reiner

    2017-05-01

    Autonomous underwater gliders offer the capability of measuring oceanic parameters continuously at high resolution in both vertical and horizontal planes, with timescales that can extend to many months. An experimental ion-sensitive field-effect transistor (ISFET) sensor measuring pH on the total scale was attached to a glider during the REP14-MED experiment in June 2014 in the Sardinian Sea in the northwestern Mediterranean. During the deployment, pH was sampled at depths of up to 1000 m along an 80 km transect over a period of 12 days. Water samples were collected from a nearby ship and analysed for dissolved inorganic carbon concentration and total alkalinity to derive the pH for validating the ISFET sensor measurements. The vertical resolution of the pH sensor was good (1 to 2 m), but stability was poor and the sensor drifted in a non-monotonous fashion. In order to remove the sensor drift, a depth-constant time-varying offset was applied throughout the water column for each dive, reducing the spread of the data by approximately two-thirds. Furthermore, the ISFET sensor required temperature- and pressure-based corrections, which were achieved using linear regression. Correcting for this decreased the apparent sensor pH variability by a further 13 to 31 %. Sunlight caused an apparent sensor pH decrease of up to 0.1 in surface waters around local noon, highlighting the importance of shielding the sensor from light in future deployments. The corrected pH from the ISFET sensor is presented along with potential temperature, salinity, potential density anomalies (σθ), and dissolved oxygen concentrations (c(O2)) measured by the glider, providing insights into the physical and biogeochemical variability in the Sardinian Sea. The pH maxima were identified close to the depth of the summer chlorophyll maximum, where high c(O2) values were also found. Longitudinal pH variations at depth (σθ > 28. 8 kg m-3) highlighted the variability of water masses in the Sardinian

  9. Contributions to the Theory of Measures of Association for Ordinal Variables

    OpenAIRE

    Ekström, Joakim

    2009-01-01

    In this thesis, we consider measures of association for ordinal variables from a theoretical perspective. In particular, we study the phi-coefficient, the tetrachoric correlation coefficient and the polychoric correlation coefficient. We also introduce a new measure of association for ordinal variables, the empirical polychoric correlation coefficient, which has better theoretical properties than the polychoric correlation coefficient, including greatly enhanced robustness. In the first artic...

  10. Multi-attribute integrated measurement of node importance in complex networks

    Science.gov (United States)

    Wang, Shibo; Zhao, Jinlou

    2015-11-01

    The measure of node importance in complex networks is very important to the research of networks stability and robustness; it also can ensure the security of the whole network. Most researchers have used a single indicator to measure the networks node importance, so that the obtained measurement results only reflect certain aspects of the networks with a loss of information. Meanwhile, because of the difference of networks topology, the nodes' importance should be described by combining the character of the networks topology. Most of the existing evaluation algorithms cannot completely reflect the circumstances of complex networks, so this paper takes into account the degree of centrality, the relative closeness centrality, clustering coefficient, and topology potential and raises an integrated measuring method to measure the nodes' importance. This method can reflect nodes' internal and outside attributes and eliminate the influence of network structure on the node importance. The experiments of karate network and dolphin network show that networks topology structure integrated measure has smaller range of metrical result than a single indicator and more universal. Experiments show that attacking the North American power grid and the Internet network with the method has a faster convergence speed than other methods.

  11. Canonical Measure of Correlation (CMC) and Canonical Measure of Distance (CMD) between sets of data Part 2. Variable reduction.

    Science.gov (United States)

    Consonni, V; Ballabio, D; Manganaro, A; Mauri, A; Todeschini, R

    2009-08-19

    This paper proposes a new method for determining the subset of variables that reproduce as well as possible the main structural features of the complete data set. This method can be useful for pre-treatment of large data sets since it allows discarding variables that contain redundant information. Reducing the number of variables often allows one to better investigate data structure and obtain more stable results from multivariate modelling methods. The novel method is based on the recently proposed canonical measure of correlation (CMC index) between two sets of variables [R. Todeschini, V. Consonni, A. Manganaro, D. Ballabio, A. Mauri, Canonical Measure of Correlation (CMC) and Canonical Measure of Distance (CMD) between sets of data. Part 1. Theory and simple chemometric applications, Anal. Chim. Acta submitted for publication (2009)]. Following a stepwise procedure (backward elimination), each variable in turn is compared to all the other variables and the most correlated is definitively discarded. Finally, a key subset of variables being as orthogonal as possible are selected. The performance was evaluated on both simulated and real data sets. The effectiveness of the novel method is discussed by comparison with results of other well known methods for variable reduction, such as Jolliffe techniques, McCabe criteria, Krzanowski approach and its modification based on genetic algorithms, loadings of the first principal component, Key Set Factor Analysis (KSFA), Variable Inflation Factor (VIF), pairwise correlation approach, and K correlation analysis (KIF). The obtained results are consistent with those of the other considered methods; moreover, the advantage of the proposed CMC method is that calculation is very quick and can be easily implemented in any software application.

  12. 41 CFR 102-117.280 - What aspects of the TSP's performance are important to measure?

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false What aspects of the TSP... REGULATION TRANSPORTATION 117-TRANSPORTATION MANAGEMENT Transportation Service Provider (TSP) Performance § 102-117.280 What aspects of the TSP's performance are important to measure? Important TSP performance...

  13. PD-Detection vs. Loss Measurements at High Voltages with variable frequencies

    DEFF Research Database (Denmark)

    Holbøll, Joachim T.; Edin, Hans

    1999-01-01

    Partial discharge-activity (PD) in internal voids in epoxy plastic was measured at AC voltages from below inception to 3 times inception with variable frequencies in the range 0.1 to 100Hz.The results from phase/height analyses were compared to dielec-tric loss measurements and related to the app......Partial discharge-activity (PD) in internal voids in epoxy plastic was measured at AC voltages from below inception to 3 times inception with variable frequencies in the range 0.1 to 100Hz.The results from phase/height analyses were compared to dielec-tric loss measurements and related...

  14. Intraobserver and interobserver variability in CT angiography and MR angiography measurements of the size of cerebral aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hye Jeong [Hallym University College of Medicine, Department of Radiology, Kangnam Sacred Heart Hospital, Seoul (Korea, Republic of); Yoon, Dae Young; Lee, Hyung Jin [Hallym University College of Medicine, Department of Radiology, Kangdong Seong-Sim Hospital, Seoul (Korea, Republic of); Kim, Eun Soo [Hallym University College of Medicine, Department of Radiology, Hallym University Sacred Heart Hospital, Anyang, Gyeonggi-do (Korea, Republic of); Jeon, Hong Jun; Lee, Jong Young; Cho, Byung-Moon [Hallym University College of Medicine, Department of Neurosurgery, Kangdong Seong-Sim Hospital, Seoul (Korea, Republic of)

    2017-05-15

    Accurate and reliable measurement of aneurysm size is important for treatment planning. The purpose of this study was to determine intraobserver and interobserver variability of CTA and MRA for measurement of the size of cerebral aneurysms. Thirty patients with 33 unruptured cerebral aneurysms (saccular, >3 mm in their maximal dimension, with no daughter sacs or lobulations) who underwent 256-row multislice CTA, 3-D TOF MRA at 3.0T, and 3D rotational angiography (3DRA) were retrospectively analyzed. Three independent observers measured the neck, height, and width of the aneurysms using the CTA and MRA images. Intraobserver and interobserver variability of CTA and MRA measurements was evaluated using the standardized difference and intraclass correlation coefficient, with 3DRA measurements as the reference standard. In addition, the mean values of the measurements using CTA and MRA were compared with those using 3DRA. The overall intraobserver and interobserver standardized differences in CTA/MRA were 12.83-15.92%/13.48-17.45% and 14.08-17.00%/12.08-17.67%, respectively. The overall intraobserver and interobserver intraclass correlation coefficients of CTA/MRA were 0.88-0.98/0.84-0.96 and 0.86-0.98/0.85-0.95, respectively. Compared to the height and width measurements, measurements of the neck dimensions showed higher intraobserver and interobserver variability. The sizes of the cerebral aneurysms measured by CTA and MRA were 1.13-9.26 and 5.20-9.67% larger than those measured by 3DRA, respectively; however, these differences were not statistically significant. There were no noticeable differences between intraobserver and interobserver variability for both CTA- and MRA-based measurements of the size of cerebral aneurysms. (orig.)

  15. How are we measuring clinically important outcome for operative treatments in sports medicine?

    Science.gov (United States)

    Nwachukwu, Benedict U; Runyon, R Scott; Kahlenberg, Cynthia A; Gausden, Elizabeth B; Schairer, William W; Allen, Answorth A

    2017-05-01

    Minimal clinically important difference (MCID) and other measures of minimum clinical importance are increasingly recognized as important clinical considerations for evaluating the efficacy of an intervention. As our interpretation of clinical outcome evolves beyond statistical significance, psychometric properties such as MCID will be increasingly important to various stakeholders in the orthopaedic community. The purpose of this study was to: 1) describe the state of clinically important outcome reporting and 2) describe the methods used to derive these psychometric values for sports medicine patients undergoing operative treatments. A review of the MEDLINE database was performed. Studies primarily deriving and reporting clinically important outcome measures for operative interventions in sports medicine were included. Demographic, methodological and psychometric properties of included studies were extracted. Level of Evidence and the Newcastle Ottawa Scale (NOS) were used to assess study quality. Statistical analysis was primarily descriptive. Fifteen studies met inclusion criteria; 10 of the 15 studies were Level II evidence and mean NOS score was 5.3/9. Minimal detectable change (MDC) was the most commonly derived measure of clinical importance, calculated in 53.3% of studies, followed by MCID, calculated in 40.0% of studies. A combination of distribution and anchor-based methods was the most commonly used method to determine clinical importance (N = 7, 46.7%) followed by distribution only (N = 5, 33.3%). Predictors of clinically important change were reported in four studies and were most commonly related to pre-operative functional score. MDC and the MCID are the most commonly reported measures of clinically important outcome after operative treatment in sports medicine. A combination of both distribution and anchor-based methods is commonly used to derive these values. More attention should be paid to reporting outcomes that are clinically important and

  16. State-of-the-art measurements in human body composition: A moving frontier of clinical importance

    Science.gov (United States)

    Gallagher, D.; Shaheen, I.; Zafar, K.

    2010-01-01

    The measurement of human body composition allows for the estimation of body tissues, organs, and their distributions in living persons without inflicting harm. From a nutritional perspective, the interest in body composition has increased multi-fold with the global increase in the prevalence of obesity and its complications. The latter has driven in part the need for improved measurement methods with greater sensitivity and precision. There is no single gold standard for body-composition measurements in-vivo. All methods incorporate assumptions that do not apply in all individuals and the more accurate models are derived by using a combination of measurements, thereby reducing the importance of each assumption. This review will discuss why the measurement of body composition or human phenotyping is important; discuss new areas where the measurement of body composition (human phenotyping) is recognized as having important application; and will summarize recent advances made in new methodology. Reference will also be made to areas we cannot yet measure due to the lack of appropriate measurement methodologies, most especially measurements methods that provide information on kinetic states (not just static state) and metabolic function. PMID:21234275

  17. Attitude importance as a moderator of the relationship between implicit and explicit attitude measures.

    Science.gov (United States)

    Karpinski, Andrew; Steinman, Ross B; Hilton, James L

    2005-07-01

    The authors examined attitude importance as a moderator of the relationship between the Implicit Association Test (IAT) and explicit attitude measures. In Study 1 (N = 194), as ratings of attitude importance regarding the 2000 presidential election increased, the strength of the relationship between a Bush-Gore IAT and explicit attitude measures also increased. Study 2 provided a conceptual replication of these results using attitudes toward Coke and Pepsi (N = 112). In addition, across both studies, explicit attitude measures were better predictors of deliberative behaviors than IAT scores. In Study 3 (N = 77), the authors examined the role of elaboration as a mechanism by which attitude importance may moderate IAT-explicit attitude correlations. As predicted, increased elaboration resulted in stronger IAT-explicit attitude correlations. Other possible mechanisms by which attitude importance may moderate the IAT-explicit attitude relationship also are discussed.

  18. LAI Measurement With Hemispherical Photographs At Variable Conditions For Assessment Of Remotely Sensed Estimations

    Science.gov (United States)

    Alexandridis, Thomas K.; Stavridou, Domna; Strati, Stavroula; Monachou, Styliani; Silleos, Nikolaos

    2013-12-01

    The leaf area index (LAI) of a plant canopy is defined as its leaf area per unit of ground area. It is an important input parameter for several studies related to water, gases and energy exchange on the Earth surface, and several algorithms have been developed to estimate LAI from remotely sensed images. Nevertheless, in-situ estimations are required for the development and validation of these algorithms, which is often the most costly part of a project. Various source of errors during acquisition or analysis of digital hemispherical canopy photography have been reported, such as exposure and evenness of sky lighting. Several instructions have been found in literature, however some seem arbitrarily related to the automatic exposure of the camera, and further investigation is needed to achieve standards. The aim of this work is to identify a procedure for in-situ hemispherical lens photography and processing that guarantees comparable measurements across variable acquisition conditions, in order to be used as validation of remotely sensed LAI maps. The experimental design is based on the assumption that LAI should be constant in a site throughout the day, and in various cloud conditions. The effect of variable illumination conditions has been examined with taking bihourly time-series of hemispherical photos at the exact same locations, under the same canopy conditions. Two calibration techniques were tested to minimize the effect of clear vs. overcast sky. Finally, two computer software specialized in hemispherical photos processing were used. Results suggest that calibration using the sky lighting is a good means for repeatability of observations under closed canopies. Also, CAN-EYE and HEMISFER software are capable of processing large numbers of hemispherical photographs accurately. The resulting in-situ LAI measurements were used to validate LAI maps from various satellites: ENVISAT MERIS, Terra MODIS, and SPOT VEGETATION.

  19. Midiendo la variabilidad en caracteres cualitativos = Measuring variability in qualitative characteristics

    Directory of Open Access Journals (Sweden)

    Jesús Basulto Santos

    2012-12-01

    Full Text Available El estudio de la variabilidad en caracteres categóricos rara vez es abordado. A partir de un enfoque menos usado de la variabilidad en variables cuantitativas, el de la disparidad, distinto al de la dispersión que, por ejemplo, proporciona la varianza, se propone la construcción de dos coeficientes de medida de la variabilidad en variables cualitativas o categóricas a los que llamamos coeficientes de disparidad. La sencillez y proximidad de los mismos permiten que sean abordados en un curso introductorio de estadística descriptiva. Ejemplos sencillos son ofrecidos para introducir las medidas y para, también, que el profesor constate la idea que el alumno tiene sobre variabilidad, dispersión y disparidad. The study of variability in categorical characteristics is rarely discussed. From a less used viewpoint of variability in quantitative variables, as it is the one of dissimilarity, which is different from the dispersion that, for example, the variance provides, we propose the construction of two coefficients that measure the variability in qualitative or categorical variables, which we call coefficients of dissimilarity. Simple examples are provided to introduce the measures, so that the teacher can also evaluate the idea students have about variability, dispersion and dissimilarity.

  20. Reproducibility of heart rate variability and baroreflex sensitivity measurements in children

    NARCIS (Netherlands)

    Dietrich, Andrea; Rosmalen, Judith G. M.; Althaus, Monika; van Roon, Arie M.; Mulder, Lambertus J. M.; Minderaa, Ruud B.; Oldehinkel, Albertine J.; Riese, Harriette

    Despite their extensive use, the reproducibility of cardiac autonomic measurements in children is not well-known. We investigated the reproducibility of short-term continuous measurements of heart rate (HR), heart rate variability (HRV, time and frequency domain), and spontaneous baroreflex

  1. Analysis of impedance measurements of a suspension of microcapsules using a variable length impedance measurement cell

    Directory of Open Access Journals (Sweden)

    Dejan Krizaj

    2012-10-01

    Full Text Available Electrical impedance measurements of the suspensions have to take into account the double layer impedance that is due to a very thin charged layer formed at the electrode-electrolite interface. A dedicated measuring cell that enables variation of the distance between the electrodes was developed for investigation of electrical properties of suspensions using two electrode impedance measurements. By varying the distance between the electrodes it is possible to separate the double layer and the suspension impedance from the measured data. From measured and extracted impedances electrical lumped models have been developed. The error of non inclusion of the double layer impedance has been analyzed. The error depends on the frequency of the measurements as well as on the distance between the electrodes.

  2. Statistical Primer for Athletic Trainers: The Essentials of Understanding Measures of Reliability and Minimal Important Change.

    Science.gov (United States)

    Riemann, Bryan L; Lininger, Monica R

    2018-01-01

      To describe the concepts of measurement reliability and minimal important change.   All measurements have some magnitude of error. Because clinical practice involves measurement, clinicians need to understand measurement reliability. The reliability of an instrument is integral in determining if a change in patient status is meaningful.   Measurement reliability is the extent to which a test result is consistent and free of error. Three perspectives of reliability-relative reliability, systematic bias, and absolute reliability-are often reported. However, absolute reliability statistics, such as the minimal detectable difference, are most relevant to clinicians because they provide an expected error estimate. The minimal important difference is the smallest change in a treatment outcome that the patient would identify as important.   Clinicians should use absolute reliability characteristics, preferably the minimal detectable difference, to determine the extent of error around a patient's measurement. The minimal detectable difference, coupled with an appropriately estimated minimal important difference, can assist the practitioner in identifying clinically meaningful changes in patients.

  3. The measurement of dynamic poverty with geographical and intertemporal price variability: evidence from Rwanda

    OpenAIRE

    Christophe Muller

    1998-01-01

    Little attention has been devoted to the effects of absolute and relative prices variability at local and seasonal levels, for the measurement of living standards in LDCs. In particular, it is not known if a substantial share of welfare or poverty indicators may be the consequence of price differences rather than of differences in living standards across households and seasons. With exogenous poverty lines, we show how the directions of effects of accounting for price variability can be theor...

  4. Measurement and control of optical nonlinearities of importance to glass laser fusion systems

    Energy Technology Data Exchange (ETDEWEB)

    Kurnit, N.A.; Shimada, T.; Sorem, M.S.; Taylor, A.J.; Rodriguez, G.; Clement, T.S.; James, D.F.V.; Milonni, P.W.

    1996-12-31

    Results of a number of studies carried out at Los Alamos, both experimental and theoretical, of nonlinear optical phenomena important to the design of the National Ignition Facility are summarized. These include measurements of nonlinear index coefficients, Raman scattering in atmospheric oxygen, and theoretical studies of harmonic conversion. The measurements were made by two different techniques in order to increase confidence in the results. One method was an application of a recently-developed technique for measuring the amplitude and phase of an ultrashort pulse by Frequency-Resolved Optical Gating (FROG). The other utilized a modified version of the Z-scan technique that measures beam distortion introduced by scanning a sample through the focus of a beam. The measurements by both techniques for fused silica were consistent with the lower range of previously measured values, indicating that it should not be necessary to further expand the beam size in the NIF to stay below the self-focusing threshold.

  5. Variability in size-selective mortality obscures the importance of larval traits to recruitment success in a temperate marine fish.

    Science.gov (United States)

    Murphy, Hannah M; Warren-Myers, Fletcher W; Jenkins, Gregory P; Hamer, Paul A; Swearer, Stephen E

    2014-08-01

    In fishes, the growth-mortality hypothesis has received broad acceptance as a driver of recruitment variability. Recruitment is likely to be lower in years when the risk of starvation and predation in the larval stage is greater, leading to higher mortality. Juvenile snapper, Pagrus auratus (Sparidae), experience high recruitment variation in Port Phillip Bay, Australia. Using a 5-year (2005, 2007, 2008, 2010, 2011) data set of larval and juvenile snapper abundances and their daily growth histories, based on otolith microstructure, we found selective mortality acted on larval size at 5 days post-hatch in 4 low and average recruitment years. The highest recruitment year (2005) was characterised by no size-selective mortality. Larval growth of the initial larval population was related to recruitment, but larval growth of the juveniles was not. Selective mortality may have obscured the relationship between larval traits of the juveniles and recruitment as fast-growing and large larvae preferentially survived in lower recruitment years and fast growth was ubiquitous in high recruitment years. An index of daily mortality within and among 3 years (2007, 2008, 2010), where zooplankton were concurrently sampled with ichthyoplankton, was related to per capita availability of preferred larval prey, providing support for the match-mismatch hypothesis. In 2010, periods of low daily mortality resulted in no selective mortality. Thus both intra- and inter-annual variability in the magnitude and occurrence of selective mortality in species with complex life cycles can obscure relationships between larval traits and population replenishment, leading to underestimation of their importance in recruitment studies.

  6. Resolving meso-scale seabed variability using reflection measurements from an autonomous underwater vehicle.

    Science.gov (United States)

    Holland, Charles W; Nielsen, Peter L; Dettmer, Jan; Dosso, Stan

    2012-02-01

    Seabed geoacoustic variability is driven by geological processes that occur over a wide spectrum of space-time scales. While the acoustics community has some understanding of horizontal fine-scale geoacoustic variability, less than O(10(0)) m, and large-scale variability, greater than O(10(3)) m, there is a paucity of data resolving the geoacoustic meso-scale O(10(0)-10(3)) m. Measurements of the meso-scale along an ostensibly "benign" portion of the outer shelf reveal three classes of variability. The first class was expected and is due to horizontal variability of layer thicknesses: this was the only class that could be directly tied to seismic reflection data. The second class is due to rapid changes in layer properties and/or boundaries, occurring over scales of meters to hundreds of meters. The third class was observed as rapid variations of the angle/frequency dependent reflection coefficient within a single observation and is suggestive of variability at scales of meter or less. Though generally assumed to be negligible in acoustic modeling, the second and third classes are indicative of strong horizontal geoacoustic variability within a given layer. The observations give early insight into possible effects of horizontal geoacoustic variability on long-range acoustic propagation and reverberation. © 2012 Acoustical Society of America

  7. Measured and calculated variables of global oxygenation in healthy neonatal foals.

    Science.gov (United States)

    Wong, David M; Hepworth-Warren, Kate L; Sponseller, Beatrice T; Howard, Joan M; Wang, Chong

    2017-02-01

    OBJECTIVE To assess multiple central venous and arterial blood variables that alone or in conjunction with one another reflect global oxygenation status in healthy neonatal foals. ANIMALS 11 healthy neonatal foals. PROCEDURES Central venous and arterial blood samples were collected from healthy neonatal foals at 12, 24, 36, 48, 72, and 96 hours after birth. Variables measured from central venous and arterial blood samples included oxygen saturation of hemoglobin, partial pressure of oxygen, lactate concentration, partial pressure of carbon dioxide, and pH. Calculated variables included venous-to-arterial carbon dioxide gap, estimated oxygen extraction ratio, ratio of partial pressure of oxygen in arterial blood to the fraction of inspired oxygen, bicarbonate concentration, base excess, and blood oxygen content. RESULTS Significant differences between arterial and central venous blood obtained from neonatal foals were detected for several variables, particularly partial pressure of oxygen, oxygen saturation of hemoglobin, and oxygen content. In addition, the partial pressure of carbon dioxide in central venous blood samples was significantly higher than the value for corresponding arterial blood samples. Several temporal differences were detected for other variables. CONCLUSIONS AND CLINICAL RELEVANCE Results of this study provided information about several variables that reflect global oxygenation in healthy neonatal foals. Values for these variables in healthy foals can allow for comparison with values for critically ill foals in future studies. Comparison of these variables between healthy and ill foals may aid in treatment decisions and prognosis of clinical outcome for critically ill foals.

  8. Analysis of a Pulse Rate Variability Measurement Using a Smartphone Camera

    Directory of Open Access Journals (Sweden)

    András Bánhalmi

    2018-01-01

    Full Text Available Background. Heart rate variability (HRV provides information about the activity of the autonomic nervous system. Because of the small amount of data collected, the importance of HRV has not yet been proven in clinical practice. To collect population-level data, smartphone applications leveraging photoplethysmography (PPG and some medical knowledge could provide the means for it. Objective. To assess the capabilities of our smartphone application, we compared PPG (pulse rate variability (PRV with ECG (HRV. To have a baseline, we also compared the differences among ECG channels. Method. We took fifty parallel measurements using iPhone 6 at a 240 Hz sampling frequency and Cardiax PC-ECG devices. The correspondence between the PRV and HRV indices was investigated using correlation, linear regression, and Bland-Altman analysis. Results. High PPG accuracy: the deviation of PPG-ECG is comparable to that of ECG channels. Mean deviation between PPG-ECG and two ECG channels: RR: 0.01 ms–0.06 ms, SDNN: 0.78 ms–0.46 ms, RMSSD: 1.79 ms–1.21 ms, and pNN50: 2.43%–1.63%. Conclusions. Our iPhone application yielded good results on PPG-based PRV indices compared to ECG-based HRV indices and to differences among ECG channels. We plan to extend our results on the PPG-ECG correspondence with a deeper analysis of the different ECG channels.

  9. Influence of temporally variable groundwater flow conditions on point measurements and contaminant mass flux estimations

    DEFF Research Database (Denmark)

    Rein, Arno; Bauer, S; Dietrich, P

    2009-01-01

    Monitoring of contaminant concentrations, e.g., for the estimation of mass discharge or contaminant degradation rates. often is based on point measurements at observation wells. In addition to the problem, that point measurements may not be spatially representative. a further complication may arise...... information representing observation wells installed along control planes using different well frequencies and configurations. Results of the scenario simulations show that temporally variable flow conditions can lead to significant temporal fluctuations of the concentration and thus are a substantial source...... is present, the concentration variability due to a fluctuating groundwater flow direction varies significantly within the control plane and between the different realizations. Determination of contaminant mass fluxes is also influenced by the temporal variability of the concentration measurement, especially...

  10. Should We Give up Domain Importance Weighting in QoL Measures?

    Science.gov (United States)

    Hsieh, Chang-ming

    2012-01-01

    The purpose of this article is to examine the recent claims calling for abolishing domain importance weighting in quality of life (QoL) measures by considering the evidence conceptually and empirically. Based on a close review of evidence presented to date, it is suggested that using the range-of-affect hypothesis as a possible explanation of the…

  11. Comparing measurement error correction methods for rate-of-change exposure variables in survival analysis.

    Science.gov (United States)

    Veronesi, Giovanni; Ferrario, Marco M; Chambless, Lloyd E

    2013-12-01

    In this article we focus on comparing measurement error correction methods for rate-of-change exposure variables in survival analysis, when longitudinal data are observed prior to the follow-up time. Motivational examples include the analysis of the association between changes in cardiovascular risk factors and subsequent onset of coronary events. We derive a measurement error model for the rate of change, estimated through subject-specific linear regression, assuming an additive measurement error model for the time-specific measurements. The rate of change is then included as a time-invariant variable in a Cox proportional hazards model, adjusting for the first time-specific measurement (baseline) and an error-free covariate. In a simulation study, we compared bias, standard deviation and mean squared error (MSE) for the regression calibration (RC) and the simulation-extrapolation (SIMEX) estimators. Our findings indicate that when the amount of measurement error is substantial, RC should be the preferred method, since it has smaller MSE for estimating the coefficients of the rate of change and of the variable measured without error. However, when the amount of measurement error is small, the choice of the method should take into account the event rate in the population and the effect size to be estimated. An application to an observational study, as well as examples of published studies where our model could have been applied, are also provided.

  12. [Methodological issues in the measurement of alcohol consumption: the importance of drinking patterns].

    Science.gov (United States)

    Valencia Martín, José L; González, M José; Galán, Iñaki

    2014-08-01

    Measurement of alcohol consumption is essential for proper investigation of its effects on health. However, its estimation is extremely complex, because of the diversity of forms of alcohol consumption and their highly heterogeneous classification. Moreover, each form may have different effects on health; therefore, not considering the most important drinking patterns when estimating alcohol intake could mask the important role of consumption patterns in these effects. All these issues make it very difficult to compare the results of different studies and to establish consistent associations for understanding the true effects of alcohol consumption, both overall and specific to each drinking pattern. This article reviews the main methods and sources of information available in Spain for estimating the most important aspects of alcohol consumption, as well as the most frequent methodological problems encountered in the measurement and classification of drinking patterns.

  13. Is temperature an important variable in recovery after mild traumatic brain injury? [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Coleen M. Atkins

    2017-11-01

    Full Text Available With nearly 42 million mild traumatic brain injuries (mTBIs occurring worldwide every year, understanding the factors that may adversely influence recovery after mTBI is important for developing guidelines in mTBI management. Extensive clinical evidence exists documenting the detrimental effects of elevated temperature levels on recovery after moderate to severe TBI. However, whether elevated temperature alters recovery after mTBI or concussion is an active area of investigation. Individuals engaged in exercise and competitive sports regularly experience body and brain temperature increases to hyperthermic levels and these temperature increases are prolonged in hot and humid ambient environments. Thus, there is a strong potential for hyperthermia to alter recovery after mTBI in a subset of individuals at risk for mTBI. Preclinical mTBI studies have found that elevating brain temperature to 39°C before mTBI significantly increases neuronal death within the cortex and hippocampus and also worsens cognitive deficits. This review summarizes the pathology and behavioral problems of mTBI that are exacerbated by hyperthermia and discusses whether hyperthermia is a variable that should be considered after concussion and mTBI. Finally, underlying pathophysiological mechanisms responsible for hyperthermia-induced altered responses to mTBI and potential gender considerations are discussed.

  14. Correlation of Blood Pressure Variability as Measured By Clinic, Self-measurement at Home, and Ambulatory Blood Pressure Monitoring.

    Science.gov (United States)

    Abellán-Huerta, José; Prieto-Valiente, Luis; Montoro-García, Silvia; Abellán-Alemán, José; Soria-Arcos, Federico

    2018-02-09

    Blood pressure variability (BPV) has been postulated as a potential predictor of cardiovascular outcomes. No agreement exists as to which measurement method is best for BPV estimation. We attempt to assess the correlation between BPV obtained at the doctor's office, self-measurement at home (SMBP) and ambulatory BP monitoring (ABPM). Eight weekly clinic BP measurements, 2 SMBP series, and 1 24-hour ABPM recording were carried out in a sample of treated hypertensive patients. BPV was calculated using the SD, the "coefficient of variation" and the "average real variability." Determinants of short-, mid-, and long-term BPV (within each measurement method) were also calculated. The different BPV determinants were correlated "intramethod" and "intermethod" by linear regression test. For the 104 patients (66.5 ± 7.7 years, 58.7% males), the ABPM BPV (SD, systolic/diastolic: 14.5 ± 3.1/9.8 ± 2.5 mm Hg) was higher than the SMBP (12.2 ± 9.8/7.4 ± 5.8 mm Hg; P < 0.001) and clinic BPV (10 ± 8.9/5.9 ± 4.9 mm Hg; P = 0.001). The main BPV correlation between methods was weak, with a maximum R2 = 0.17 (P < 0.001) between clinic and SMBP systolic BPV. The "intramethod" correlation of BPV yielded a maximum R2 = 0.21 (P < 0.001) between morning diastolic SMBP intershift/intermeans variability. The "intermethod" correlation of short-, mid-, and long-term BPV determinants was weak (maximum R2 = 0.22, P < 0.001, between clinic intraday variability/SMBP morning intershift variability). The "intramethod" and "intermethod" correlation between BPV determinants was weak or nonexistent, even when comparing determinants reflecting the same type of temporal BPV. Our data suggest that BPV reflects a heterogeneous phenomenon that strongly depends on the estimation method and the time period evaluated.

  15. Classical and NIR measurements of the quality and nutritional parameters of apples: a methodological study of intra-fruit variability

    Directory of Open Access Journals (Sweden)

    Lateur, M.

    2012-01-01

    Full Text Available For the past few years, research has focused on the application of Near Infrared Spectroscopy (NIR techniques to analyze the quality of apple varieties. As all fruit quality and nutritional parameters are affected by many factors, to standardize the sampling methods prior to analysis is very important. In this study, the intra-fruit variability of apple varieties in terms of quality parameters (sugar, total polyphenol and vitamin C content was examined. The adequacy of the protocols usually applied to analyze apple quality (reference analyses of a representative sample of the apple and NIR measurements collected at four points 45° from each other in the equatorial region of the apple was then investigated. The reference values for the quality parameters showed important intra-fruit variability for all quality parameters analyzed. The results also showed that there was little difference between the mean value at the four points and the mean value of the entire apple. This suggested that a mean value obtained from a representative sample of an apple is enough to assess the variability within the fruit and to estimate, with precision, the content of the quality parameters. The results of NIR spectroscopy showed that measurement at the four target points is suitable for predicting quality parameters precisely. The study concluded that standardized reference analyses should be done on a representative fruit sample of an apple and spectral measurements made at four points 45° from each other in the equatorial region of the apple.

  16. Impulsive buying tendency: Measuring important relationships with a new perspective and an indigenous scale

    Directory of Open Access Journals (Sweden)

    Anant Jyoti Badgaiyan

    2016-12-01

    Full Text Available With the opening up of the economy and the proliferation of mall culture, the economic relevance of impulsive buying behaviour has assumed significance. Impulsive buying behaviour is better understood by examining the impulsive buying tendency that shapes such behaviour, and since consumer behaviour differs across cultures, by incorporating an indigenous perspective in understanding and measuring the tendency. Studies were conducted to develop an Indian scale for measuring impulsive buying tendency and to validate it by examining its association with other relevant variables. A two factor, 8-item scale was developed; a significant positive relationship was seen between impulsive buying tendency and impulsive buying behaviour, and the relationship between impulsive buying tendency and self-control was found to be inversely significant. Results also showed significant relationship between impulsive buying tendency and the two personality constructs of Conscientiousness and Extraversion.

  17. Variability of M-mode versus two-dimensional echocardiography measurements in children with dilated cardiomyopathy.

    Science.gov (United States)

    Lee, Caroline K; Margossian, Renee; Sleeper, Lynn A; Canter, Charles E; Chen, Shan; Tani, Lloyd Y; Shirali, Girish; Szwast, Anita; Tierney, Elif Seda Selamet; Campbell, M Jay; Golding, Fraser; Wang, Yanli; Altmann, Karen; Colan, Steven D

    2014-04-01

    M-mode and 2-dimensional (2D) echocardiographic imaging are routinely used to quantify left-ventricular (LV) size and function in pediatric patients with dilated cardiomyopathy (DCM). The reproducibility of and correlation between these techniques are unknown. This analysis sought to compare interreader, intrareader, and interacquisition reproducibility of M-mode versus 2D measurements in pediatric DCM patients. The Ventricular Volume Variability study of the Pediatric Heart Network is a multicenter, prospective, observational study assessing the course of chronic DCM in children. Two sonographers performed baseline image acquisitions locally, and two readers performed measurements at the echocardiographic core laboratory. One reader repeated measurements 1 month later. These data were used to assess reproducibility and agreement between M-mode and 2D measurements. One hundred sixty-nine subjects were enrolled. M-mode had similar or greater reproducibility in both intrareader and interreader settings for LV dimensions, shortening fraction (SF), and most wall thicknesses. In contrast, 2D reproducibility was similar or better for nearly all variables in the interacquisition setting but not for SF. Interacquisition variability was approximately twice the intrareader variability. LV dimensions by either modality consistently had high reproducibility and had the highest agreement between modalities. In pediatric DCM patients, variability of linear echocardiographic assessment could be minimized by relying on a single reader and using a consistent method (M-mode or 2D) for serial measurements, preferably M-mode when SF is the primary variable of interest. Except for LV dimensions, M-mode and 2D values should not be used interchangeably due to poor agreement.

  18. Seasonal variability of the Red Sea, from GRACE time-variable gravity and altimeter sea surface height measurements

    Science.gov (United States)

    Wahr, John; Smeed, David; Leuliette, Eric; Swenson, Sean

    2014-05-01

    Seasonal variability of sea surface height and mass within the Red Sea, occurs mostly through the exchange of heat with the atmosphere and wind-driven inflow and outflow of water through the strait of Bab el Mandab that opens into the Gulf of Aden to the south. The seasonal effects of precipitation and evaporation, of water exchange through the Suez Canal to the north, and of runoff from the adjacent land, are all small. The flow through the Bab el Mandab involves a net mass transfer into the Red Sea during the winter and a net transfer out during the summer. But that flow has a multi-layer pattern, so that in the summer there is actually an influx of cool water at intermediate (~100 m) depths. Thus, summer water in the southern Red Sea is warmer near the surface due to higher air temperatures, but cooler at intermediate depths (especially in the far south). Summer water in the northern Red Sea experiences warming by air-sea exchange only. The temperature profile affects the water density, which impacts the sea surface height but has no effect on vertically integrated mass. Here, we study this seasonal cycle by combining GRACE time-variable mass estimates, altimeter (Jason-1, Jason-2, and Envisat) measurements of sea surface height, and steric sea surface height contributions derived from depth-dependent, climatological values of temperature and salinity obtained from the World Ocean Atlas. We find good consistency, particularly in the northern Red Sea, between these three data types. Among the general characteristics of our results are: (1) the mass contributions to seasonal SSHT variations are much larger than the steric contributions; (2) the mass signal is largest in winter, consistent with winds pushing water into the Red Sea through the Strait of Bab el Mandab in winter, and out during the summer; and (3) the steric signal is largest in summer, consistent with summer sea surface warming.

  19. Measuring pH variability using an experimental sensor on an underwater glider

    Directory of Open Access Journals (Sweden)

    M. P. Hemming

    2017-05-01

    Full Text Available Autonomous underwater gliders offer the capability of measuring oceanic parameters continuously at high resolution in both vertical and horizontal planes, with timescales that can extend to many months. An experimental ion-sensitive field-effect transistor (ISFET sensor measuring pH on the total scale was attached to a glider during the REP14-MED experiment in June 2014 in the Sardinian Sea in the northwestern Mediterranean. During the deployment, pH was sampled at depths of up to 1000 m along an 80 km transect over a period of 12 days. Water samples were collected from a nearby ship and analysed for dissolved inorganic carbon concentration and total alkalinity to derive the pH for validating the ISFET sensor measurements. The vertical resolution of the pH sensor was good (1 to 2 m, but stability was poor and the sensor drifted in a non-monotonous fashion. In order to remove the sensor drift, a depth-constant time-varying offset was applied throughout the water column for each dive, reducing the spread of the data by approximately two-thirds. Furthermore, the ISFET sensor required temperature- and pressure-based corrections, which were achieved using linear regression. Correcting for this decreased the apparent sensor pH variability by a further 13 to 31 %. Sunlight caused an apparent sensor pH decrease of up to 0.1 in surface waters around local noon, highlighting the importance of shielding the sensor from light in future deployments. The corrected pH from the ISFET sensor is presented along with potential temperature, salinity, potential density anomalies (σθ, and dissolved oxygen concentrations (c(O2 measured by the glider, providing insights into the physical and biogeochemical variability in the Sardinian Sea. The pH maxima were identified close to the depth of the summer chlorophyll maximum, where high c(O2 values were also found. Longitudinal pH variations at depth (σθ > 28. 8 kg m−3 highlighted the variability of

  20. Precipitation measurement and modelling: Uncertainty, variability, observations, ensemble simulation and downscaling

    Science.gov (United States)

    Langousis, Andreas; Deidda, Roberto; Carsteanu, Alin Andrei; Onof, Chistian; Burlando, Paolo; Uijlenhoet, Remko; Bárdossy, András

    2018-01-01

    Assessing the intermittent and highly variable character of precipitation in space and time, and modelling its statistical structure, are of crucial importance in a variety of applications, such as the evaluation of hydrological impacts of climate change, assessment of the availability of water resources in space and time, and flood risk estimation and forecasting, to name a few.

  1. Estimating minimal clinically important differences of upper extremity measures early after stroke

    Science.gov (United States)

    Lang, Catherine E.; Edwards, Dorothy F.; Birkenmeier, Rebecca L.; Dromerick, Alexander W.

    2010-01-01

    Objective To estimate minimal clinically important difference values of several upper extremity measures early after stroke. Design Data in this report were collected during the VECTORS trial, an acute, single-blind randomized controlled trial of Constraint Induced Movement Therapy. Subjects were tested at the pre-randomization baseline assessment (average of 9.5 days post stroke), and the first post-treatment assessment (25.9 days post stroke). At each time point, the affected upper extremity was evaluated with a battery of 6 tests. At the second assessment, subjects were also asked to provide a global rating of perceived changes in their affected upper extremity. Anchor-based minimal clinically important difference values were calculated separately for the affected dominant upper extremities and the affected non-dominant upper extremities for each of the 6 tests. Setting Inpatient rehabilitation hospital. Participants Fifty-two people with hemiparesis post stroke. Interventions Not applicable. Main Outcome Measures Estimated minimal clinically important difference values for grip strength, composite upper extremity strength, Action Research Arm Test (ARAT), Wolf Motor Function Test (WMFT), Motor Activity Log (MAL), and duration of upper extremity use as measured with accelerometry. Results Minimal clinically important difference values for grip strength were 5.0 and 6.2 kg for the affected dominant and non-dominant sides respectively. Minimal clinically important difference values for the ARAT were 12 and 17 points, for the WMFT Function score were 1.0 and 1.2 points, and for the MAL How well score were 1.0 and 1.1 points for the two sides respectively. Minimal clinically important difference values were indeterminate for the dominant (composite strength), the non-dominant (WMFT Time score) or for both affected sides (duration of use) for the other measures. Conclusions Our data provide some of the first estimates of minimal clinically important difference values

  2. Uncertainty Quantification Reveals the Importance of Data Variability and Experimental Design Considerations for in Silico Proarrhythmia Risk Assessment

    Directory of Open Access Journals (Sweden)

    Kelly C. Chang

    2017-11-01

    Full Text Available The Comprehensive in vitro Proarrhythmia Assay (CiPA is a global initiative intended to improve drug proarrhythmia risk assessment using a new paradigm of mechanistic assays. Under the CiPA paradigm, the relative risk of drug-induced Torsade de Pointes (TdP is assessed using an in silico model of the human ventricular action potential (AP that integrates in vitro pharmacology data from multiple ion channels. Thus, modeling predictions of cardiac risk liability will depend critically on the variability in pharmacology data, and uncertainty quantification (UQ must comprise an essential component of the in silico assay. This study explores UQ methods that may be incorporated into the CiPA framework. Recently, we proposed a promising in silico TdP risk metric (qNet, which is derived from AP simulations and allows separation of a set of CiPA training compounds into Low, Intermediate, and High TdP risk categories. The purpose of this study was to use UQ to evaluate the robustness of TdP risk separation by qNet. Uncertainty in the model parameters used to describe drug binding and ionic current block was estimated using the non-parametric bootstrap method and a Bayesian inference approach. Uncertainty was then propagated through AP simulations to quantify uncertainty in qNet for each drug. UQ revealed lower uncertainty and more accurate TdP risk stratification by qNet when simulations were run at concentrations below 5× the maximum therapeutic exposure (Cmax. However, when drug effects were extrapolated above 10× Cmax, UQ showed that qNet could no longer clearly separate drugs by TdP risk. This was because for most of the pharmacology data, the amount of current block measured was <60%, preventing reliable estimation of IC50-values. The results of this study demonstrate that the accuracy of TdP risk prediction depends both on the intrinsic variability in ion channel pharmacology data as well as on experimental design considerations that preclude an

  3. Performance evaluation of the short-time objective intelligibility measure with different band importance functions

    DEFF Research Database (Denmark)

    Heidemann Andersen, Asger; de Haan, Jan Mark; Tan, Zheng-Hua

    Methods for speech intelligibility prediction are quickly becoming popular tools within the speech processing community. Such methods can easily and objectively estimate the effectiveness of different speech enhancement schemes. The short-time objective intelligibility (STOI) measure has enjoyed...... particular popularity due to its simplicity and its proven ability to provide accurate predictions across a wide range of conditions. The STOI measure has a simple structure which is similar to many other intelligibility measures: 1) clean and degraded speech signals are split into one-third octave bands......, is that all frequency bands are equally weighted in the final measure. This is in contrast to classical methods such as the speech intelligibility index (SII) which employs empirically determined band importance functions (BIFs), specifying the relative contribution of each frequency band to intelligibility...

  4. The importance of measuring growth in response to intervention models: Testing a core assumption.

    Science.gov (United States)

    Schatschneider, Christopher; Wagner, Richard K; Crawford, Elizabeth C

    2008-01-01

    A core assumption of response to instruction or intervention (RTI) models is the importance of measuring growth in achievement over time in response to effective instruction or intervention. Many RTI models actively monitor growth for identifying individuals who need different levels of intervention. A large-scale (N=23,438), two-year longitudinal study of first grade children was carried out to compare the predictive validity of measures of achievement status, growth in achievement, and their combination for predicting future reading achievement. The results indicate that under typical conditions, measures of growth do not make a contribution to prediction that is independent of measures of achievement status. These results question the validity of a core assumption of RTI models.

  5. Measurement of heart rate variability using off-the-shelf smart phones.

    Science.gov (United States)

    Huang, Ren-You; Dung, Lan-Rong

    2016-01-29

    The cardiac parameters, such as heart rate (HR) and heart rate variability (HRV), are very important physiological data for daily healthcare. Recently, the camera-based photoplethysmography techniques have been proposed for HR measurement. These techniques allow us to estimate the HR contactlessly with low-cost camera. However, the previous works showed limit success for estimating HRV because the R-R intervals, the primary data for HRV calculation, are sensitive to noise and artifacts. This paper proposed a non-contact method to extract the blood volume pulse signal using a chrominance-based method followed by a proposed CWT-based denoising technique. The R-R intervals can then be obtained by finding the peaks in the denoised signal. In this paper, we taped 12 video clips using the frontal camera of a smart phone with different scenarios to make comparisons among our method and the other alternatives using the absolute errors between the estimated HRV metrics and the ones obtained by an ECG-accurate chest band. As shown in experiments, our algorithm can greatly reduce absolute errors of HRV metrics comparing with the related works using RGB color signals. The mean of absolute errors of HRV metrics from our method is only 3.53 ms for the static-subject video clips. The proposed camera-based method is able to produce reliable HRV metrics which are close to the ones measured by contact devices under different conditions. Thus, our method can be used for remote health monitoring in a convenient and comfortable way.

  6. Kiloampere, Variable-Temperature, Critical-Current Measurements of High-Field Superconductors.

    Science.gov (United States)

    Goodrich, L F; Cheggour, N; Stauffer, T C; Filla, B J; Lu, X F

    2013-01-01

    We review variable-temperature, transport critical-current (I c) measurements made on commercial superconductors over a range of critical currents from less than 0.1 A to about 1 kA. We have developed and used a number of systems to make these measurements over the last 15 years. Two exemplary variable-temperature systems with coil sample geometries will be described: a probe that is only variable-temperature and a probe that is variable-temperature and variable-strain. The most significant challenge for these measurements is temperature stability, since large amounts of heat can be generated by the flow of high current through the resistive sample fixture. Therefore, a significant portion of this review is focused on the reduction of temperature errors to less than ±0.05 K in such measurements. A key feature of our system is a pre-regulator that converts a flow of liquid helium to gas and heats the gas to a temperature close to the target sample temperature. The pre-regulator is not in close proximity to the sample and it is controlled independently of the sample temperature. This allows us to independently control the total cooling power, and thereby fine tune the sample cooling power at any sample temperature. The same general temperature-control philosophy is used in all of our variable-temperature systems, but the addition of another variable, such as strain, forces compromises in design and results in some differences in operation and protocol. These aspects are analyzed to assess the extent to which the protocols for our systems might be generalized to other systems at other laboratories. Our approach to variable-temperature measurements is also placed in the general context of measurement-system design, and the perceived advantages and disadvantages of design choices are presented. To verify the accuracy of the variable-temperature measurements, we compared critical-current values obtained on a specimen immersed in liquid helium ("liquid" or I c liq) at 5

  7. Challenge in Enhancing the Teaching and Learning of Variable Measurements in Quantitative Research

    Science.gov (United States)

    Kee, Chang Peng; Osman, Kamisah; Ahmad, Fauziah

    2013-01-01

    Statistical analysis is one component that cannot be avoided in a quantitative research. Initial observations noted that students in higher education institution faced difficulty analysing quantitative data which were attributed to the confusions of various variable measurements. This paper aims to compare the outcomes of two approaches applied in…

  8. Endotracheal temperature and humidity measurements in laryngectomized patients: intra- and inter-patient variability

    NARCIS (Netherlands)

    Scheenstra, R.J.; Muller, S.H.; Vincent, A.; Sinaasappel, M.; Zuur, J.K.; Hilgers, F.J.M.

    2009-01-01

    This study assesses intra- and inter-patient variability in endotracheal climate (temperature and humidity) and effects of heat and moister exchangers (HME) in 16 laryngectomized individuals, measured repeatedly (N = 47). Inhalation Breath Length (IBL) was 1.35 s without HME and 1.05 s with HME (P <

  9. Force levels in uni- and bimanual isometric tasks affect variability measures differently throughout lifespan.

    NARCIS (Netherlands)

    Smits-Engelsman, B.C.M.; Galen, G.P. van; Duysens, J.E.J.

    2004-01-01

    Ninety-four participants (age 5-93 years) performed isometric force production tasks at five different levels of their maximum voluntary contraction (MVC) with either one or two index fingers. Research questions were whether variability measures in the bimanual task condition were different compared

  10. Force levels in uni- and bimanual isometric tasks affect variability measures differently throughout lifespan

    NARCIS (Netherlands)

    Smits-Engelsman, B.C.M.; Galen, G.P. van; Duysens, J.E.J.

    2004-01-01

    Ninety-four participants (age 5-93 years) performed isometric force production tasks at five different levels of their maximum voluntary contraction (MVC) with either one or two index fingers. Research questions were whether variability measures in the bimanual task condition were different compared

  11. Measure Guideline. Replacing Single-Speed Pool Pumps with Variable Speed Pumps for Energy Savings

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, A. [Building Media and the Building America Retrofit Alliance (BARA), Wilmington, DE (United States); Easley, S. [Building Media and the Building America Retrofit Alliance (BARA), Wilmington, DE (United States)

    2012-05-01

    This measure guideline evaluates potential energy savings by replacing traditional single-speed pool pumps with variable speed pool pumps, and provides a basic cost comparison between continued uses of traditional pumps verses new pumps. A simple step-by-step process for inspecting the pool area and installing a new pool pump follows.

  12. COMPARISON OF EXPERIMENTAL-DESIGNS COMBINING PROCESS AND MIXTURE VARIABLES .2. DESIGN EVALUATION ON MEASURED DATA

    NARCIS (Netherlands)

    DUINEVELD, CAA; SMILDE, AK; DOORNBOS, DA

    The construction of a small experimental design for a combination of process and mixture variables is a problem which has not been solved completely by now. In a previous paper we evaluated some designs with theoretical measures. This second paper evaluates the capabilities of the best of these

  13. COMPARISON OF EXPERIMENTAL-DESIGNS COMBINING PROCESS AND MIXTURE VARIABLES .2. DESIGN EVALUATION ON MEASURED DATA

    NARCIS (Netherlands)

    DUINEVELD, C. A. A.; Smilde, A. K.; Doornbos, D. A.

    1993-01-01

    The construction of a small experimental design for a combination of process and mixture variables is a problem which has not been solved completely by now. In a previous paper we evaluated some designs with theoretical measures. This second paper evaluates the capabilities of the best of these

  14. Spectral measurement with a linear variable filter using a LMS algorithm

    NARCIS (Netherlands)

    Emadi, A.; Grabarnik, S.; Wu, H.; De Graaf, R.F.; Wolffenbuttel, R.F.

    2010-01-01

    This paper presents spectral measurements using a linear variable optical filter. A LVOF has been developed for operation in the 530 nm–720 nm spectral band and has been fabricated in an IC-compatible process. The LVOF has been mounted on a CMOS camera. A Least Mean Square algorithm has been

  15. Endotracheal temperature and humidity measurements in laryngectomized patients: intra- and inter-patient variability

    NARCIS (Netherlands)

    Scheenstra, R. J.; Muller, S. H.; Vincent, A.; Sinaasappel, M.; Zuur, J. K.; Hilgers, Frans J. M.

    2009-01-01

    This study assesses intra- and inter-patient variability in endotracheal climate (temperature and humidity) and effects of heat and moister exchangers (HME) in 16 laryngectomized individuals, measured repeatedly (N = 47). Inhalation Breath Length (IBL) was 1.35 s without HME and 1.05 s with HME (P

  16. The Formal Elements Art Therapy Scale: A Measurement System for Global Variables in Art

    Science.gov (United States)

    Gantt, Linda M.

    2009-01-01

    The Formal Elements Art Therapy Scale (FEATS) is a measurement system for applying numbers to global variables in two-dimensional art (drawing and painting). While it was originally developed for use with the single-picture assessment ("Draw a person picking an apple from a tree" [PPAT]), researchers can also apply many of the 14 scales of the…

  17. The Effect of Listening to Specific Musical Genre Selections on Measures of Heart Rate Variability

    Science.gov (United States)

    Orman, Evelyn K.

    2011-01-01

    University students (N = 30) individually listened to the Billboard 100 top-ranked musical selection for their most and least liked musical genre. Two minutes of silence preceded each musical listening condition, and heart rate variability (HRV) was recorded throughout. All HRV measures decreased during music listening as compared with silence.…

  18. How we eat may be as important as what we eat: eating behaviour and heart rate variability.

    Science.gov (United States)

    Ozpelit, Mehmet Emre; Ozpelit, Ebru

    2017-06-01

    Objective Diet exerts a crucial role on cardiovascular health. Evidence is mainly based on the content and the amount of dietary intakes. Some recent reports demonstrated that eating behaviour may also be of significant importance in cardiovascular health. In this study we aimed to investigate the effects of eating behaviour on heart rate variability (HRV) in healthy subjects. Methods and results In total, 521 healthy subjects with 24-hour Holter ECG recordings filled out a special questionnaire about their eating behaviour and lifestyles. From these patients, 425 subjects were healthy and had recordings suitable for analysis. Five types of eating behaviour were assessed in the questionnaire: (1) adherence to the Mediterranean diet (using the MedDietScore), (2) skipping breakfast, (3) late night eating, (4) having snacks, and (5) rapid eating. Physical exercise level and active working status of the subjects were also assessed. The root mean square of successive differences (RMSSD) was used for assessment of HRV. RMSSD values were lower in subjects skipping breakfast compared to subjects having breakfast regularly (26.32 vs 31.52 P = 0.02). Other behavioural patterns did not have any effect on the HRV parameters. Ageing, male sex, sedentary lifestyle and no active working were also found to be associated with reduced HRV in univariate analysis. In multivariate regression analysis, age and skipping breakfast were the only parameters significantly associated with a lower RMSSD (β: -0.222, P: 0.008 and β: -0.191, P: 0.020, respectively) Conclusions The findings of this study showed that skipping breakfast may be a cause of cardiac autonomic dysfunction.

  19. Comparing measured and modelled soil carbon: which site-specific variables are linked to high stability?

    Science.gov (United States)

    Robertson, Andy; Schipanski, Meagan; Ma, Liwang; Ahuja, Lajpat; McNamara, Niall; Smith, Pete; Davies, Christian

    2016-04-01

    Changes in soil carbon (C) stocks have been studied in depth over the last two decades, as net greenhouse gas (GHG) sinks are highlighted to be a partial solution to the causes of climate change. However, the stability of this soil C is often overlooked when measuring these changes. Ultimately a net sequestration in soils is far less beneficial if labile C is replacing more stable forms. To date there is no accepted framework for measuring soil C stability, and as a result there is considerable uncertainty associated with the simulated impacts of land management and land use change when using process-based systems models. However, a recent effort to equate measurable soil C fractions to model pools has generated data that help to assess the impacts of land management, and can ultimately help to reduce the uncertainty of model predictions. Our research compiles this existing fractionation data along with site metadata to create a simplistic statistical model able to quantify the relative importance of different site-specific conditions. Data was mined from 23 published studies and combined with original data to generate a dataset of 100+ land use change sites across Europe. For sites to be included they required soil C fractions isolated using the Zimmermann et al. (2007) method and specific site metadata (mean annual precipitation, MAP; mean annual temperature, MAT; soil pH; land use; altitude). Of the sites, 75% were used to develop a generalized linear mixed model (GLMM) to create coefficients where site parameters can be used to predict influence on the measured soil fraction C stocks. The remaining 25% of sites were used to evaluate uncertainty and validate this empirical model. Further, four of the aforementioned sites were used to simulate soil C dynamics using the RothC, DayCent and RZWQM2 models. A sensitivity analysis (4096 model runs for each variable applying Latin hypercube random sampling techniques) was then used to observe whether these models place

  20. Angular Size Measurements of 18 Mira Variable Stars at 2.2 microns

    Science.gov (United States)

    van Belle, G. T.; Dyck, H. M.; Benson, J. A.; Lacasse, M. G.

    1996-11-01

    We present angular size measurements of 18 oxygen-rich Mira variable stars. These data are part of a long term observational program using the Infrared Optical Telescope Array (IOTA) to characterize the observable behavior of these stars. Complementing the infrared angular size measurements, values for variable star phase, spectral type, bolometric flux, and distance were established for stars in the sample; flux and distance led to values for effective temperature (TEFF), and linear radius, respectively. We are able to define an effective temperature versus spectral type scale for Mira variables that we compare to the temperature scales for K and M giants and supergiants. TEFF'S and linear radii for these stars are shown to lie between approximately 2100 and 3200 K, and 200 and 600 Rsun, respectively. Relationships among the Mira variable parameters are explored for significant trends. Notably, the phase dependence of TEFF is shown to follow simple expectations, and examination of the radius-T relationship yields a plausible description of the V and K band light curves of these stars. A simple examination of the oscillation mode of the stars in the sample does not strongly suggest either fundamental or first-overtone oscillation as the primary mode of oscillation. This conclusion differs from that recently presented by Haniff et al. (1995), who argue that Mira variables are all first-overtone pulsators. We discuss some possible reasons for the different conclusions between the two studies.

  1. Reliability and variability of day-to-day vault training measures in artistic gymnastics.

    Science.gov (United States)

    Bradshaw, Elizabeth; Hume, Patria; Calton, Mark; Aisbett, Brad

    2010-06-01

    Inter-day training reliability and variability in artistic gymnastics vaulting was determined using a customised infra-red timing gate and contact mat timing system. Thirteen Australian high performance gymnasts (eight males and five females) aged 11-23 years were assessed during two consecutive days of normal training. Each gymnast completed a number of vault repetitions per daily session. Inter-day variability of vault run-up velocities (at -18 to -12 m, -12 to -6 m, -6 to -2 m, and -2 to 0 m from the nearest edge of the beat board), and board contact, pre-flight, and table contact times were determined using mixed modelling statistics to account for random (within-subject variability) and fixed effects (gender, number of subjects, number of trials). The difference in the mean (Mdiff) and Cohen's effect sizes for reliability assessment and intra-class correlation coefficients, and the coefficient of variation percentage (CV%) were calculated for variability assessment. Approach velocity (-18 to -2m, CV = 2.4-7.8%) and board contact time (CV = 3.5%) were less variable measures when accounting for day-to-day performance differences, than pre-flight time (CV = 17.7%) and table contact time (CV = 20.5%). While pre-flight and table contact times are relevant training measures, approach velocity and board contact time are more reliable when quantifying vaulting performance.

  2. Hypocretin measurement: shelf age of radioimmunoassay kit, but not freezer time, influences assay variability.

    Science.gov (United States)

    Keating, Glenda; Bliwise, Donald L; Saini, Prabhjyot; Rye, David B; Trotti, Lynn Marie

    2017-09-01

    The hypothalamic peptide hypocretin 1 (orexin A) may be assayed in cerebrospinal fluid to diagnose narcolepsy type 1. This testing is not commercially available, and factors contributing to assay variability have not previously been comprehensively explored. In the present study, cerebrospinal fluid hypocretin concentrations were determined in duplicate in 155 patient samples, across a range of sleep disorders. Intra-assay variability of these measures was analyzed. Inter-assay correlation between samples tested at Emory and at Stanford was high (r = 0.79, p freezer (r = 0.16, p = 0.04) and age of the kit used for assay (t = 3.64, p = 0.0004) were significant predictors of intra-kit variability in univariate analyses, only age of kit was significant in multivariate linear regression (F = 4.93, p = 0.03). Age of radioimmunoassay kit affects intra-kit variability of measured hypocretin values, such that kits closer to expiration exhibit significantly more variability.

  3. Applying Importance-Performance Analysis as a Service Quality Measure in Food Service Industry

    OpenAIRE

    Gwo-Hshiung Tzeng; Hung-Fan Chang

    2011-01-01

    As the global economy becomes a service oriented economy, food service accounts for over 20% of service revenue, with an annual growth rate of more than 3%. Compared to physical products, service features are invisible, and the production and sale occurs simultaneously. There is not easy to measure the performance of service. Therefore, the service quality of catering services is considered to be an important topic of service management. According Market Intelligence & Consulting Institute (M...

  4. BIOPHYSICAL CHARACTERISATION OF THE UNDER-APPRECIATED AND IMPORTANT RELATIONSHIP BETWEEN HEART RATE VARIABILITY AND HEART RATE

    Science.gov (United States)

    Monfredi, Oliver; Lyashkov, Alexey E; Johnsen, Anne-Berit; Inada, Shin; Schneider, Heiko; Wang, Ruoxi; Nirmalan, Mahesh; Wisloff, Ulrik; Maltsev, Victor A; Lakatta, Edward G; Zhang, Henggui; Boyett, Mark R

    2014-01-01

    Heart rate variability (beat-to-beat changes in the RR interval) has attracted considerable attention over the last 30+ years (PubMed currently lists >17,000 publications). Clinically, a decrease in heart rate variability is correlated to higher morbidity and mortality in diverse conditions, from heart disease to foetal distress. It is usually attributed to fluctuation in cardiac autonomic nerve activity. We calculated heart rate variability parameters from a variety of cardiac preparations (including humans, living animals, Langendorff-perfused heart and single sinoatrial nodal cell) in diverse species, combining this with data from previously published papers. We show that regardless of conditions, there is a universal exponential decay-like relationship between heart rate variability and heart rate. Using two biophysical models, we develop a theory for this, and confirm that heart rate variability is primarily dependent on heart rate and cannot be used in any simple way to assess autonomic nerve activity to the heart. We suggest that the correlation between a change in heart rate variability and altered morbidity and mortality is substantially attributable to the concurrent change in heart rate. This calls for re-evaluation of the findings from many papers that have not adjusted properly or at all for heart rate differences when comparing heart rate variability in multiple circumstances. PMID:25225208

  5. Association between different measurements of blood pressure variability by ABP monitoring and ankle-brachial index.

    Science.gov (United States)

    Wittke, Estefânia; Fuchs, Sandra C; Fuchs, Flávio D; Moreira, Leila B; Ferlin, Elton; Cichelero, Fábio T; Moreira, Carolina M; Neyeloff, Jeruza; Moreira, Marina B; Gus, Miguel

    2010-11-05

    Blood pressure (BP) variability has been associated with cardiovascular outcomes, but there is no consensus about the more effective method to measure it by ambulatory blood pressure monitoring (ABPM). We evaluated the association between three different methods to estimate BP variability by ABPM and the ankle brachial index (ABI). In a cross-sectional study of patients with hypertension, BP variability was estimated by the time rate index (the first derivative of SBP over time), standard deviation (SD) of 24-hour SBP; and coefficient of variability of 24-hour SBP. ABI was measured with a doppler probe. The sample included 425 patients with a mean age of 57 ± 12 years, being 69.2% women, 26.1% current smokers and 22.1% diabetics. Abnormal ABI (≤ 0.90 or ≥ 1.40) was present in 58 patients. The time rate index was 0.516 ± 0.146 mmHg/min in patients with abnormal ABI versus 0.476 ± 0.124 mmHg/min in patients with normal ABI (P = 0.007). In a logistic regression model the time rate index was associated with ABI, regardless of age (OR = 6.9, 95% CI = 1.1- 42.1; P = 0.04). In a multiple linear regression model, adjusting for age, SBP and diabetes, the time rate index was strongly associated with ABI (P < 0.01). None of the other indexes of BP variability were associated with ABI in univariate and multivariate analyses. Time rate index is a sensible method to measure BP variability by ABPM. Its performance for risk stratification of patients with hypertension should be explored in longitudinal studies.

  6. Observer variability of absolute and relative thrombus density measurements in patients with acute ischemic stroke

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Emilie M.M. [Erasmus MC - University Medical Center Rotterdam, Department of Radiology, P.O. Box 2040, Rotterdam (Netherlands); Department of Radiology, AMC, Amsterdam (Netherlands); Yoo, Albert J. [Texas Stroke Institute, Plano, TX (United States); Beenen, Ludo F.; Majoie, Charles B. [Department of Radiology, AMC, Amsterdam (Netherlands); Berkhemer, Olvert A. [Department of Radiology, AMC, Amsterdam (Netherlands); Department of Neurology, Erasmus MC, Rotterdam (Netherlands); Blanken, Mark D. den; Wismans, Carrie [AMC, Department of Biomedical Engineering and Physics, Amsterdam (Netherlands); Niessen, Wiro J. [Erasmus MC - University Medical Center Rotterdam, Department of Radiology, P.O. Box 2040, Rotterdam (Netherlands); Delft University of Technology, Faculty of Applied Sciences, Delft (Netherlands); Marquering, Henk A. [Department of Radiology, AMC, Amsterdam (Netherlands); AMC, Department of Biomedical Engineering and Physics, Amsterdam (Netherlands); Collaboration: on behalf of the MR CLEAN investigators

    2016-02-15

    Thrombus density may be a predictor for acute ischemic stroke treatment success. However, only limited data on observer variability for thrombus density measurements exist. This study assesses the variability and bias of four common thrombus density measurement methods by expert and non-expert observers. For 132 consecutive patients with acute ischemic stroke, three experts and two trained observers determined thrombus density by placing three standardized regions of interest (ROIs) in the thrombus and corresponding contralateral arterial segment. Subsequently, absolute and relative thrombus densities were determined using either one or three ROIs. Intraclass correlation coefficient (ICC) was determined, and Bland-Altman analysis was performed to evaluate interobserver and intermethod agreement. Accuracy of the trained observer was evaluated with a reference expert observer using the same statistical analysis. The highest interobserver agreement was obtained for absolute thrombus measurements using three ROIs (ICCs ranging from 0.54 to 0.91). In general, interobserver agreement was lower for relative measurements, and for using one instead of three ROIs. Interobserver agreement of trained non-experts and experts was similar. Accuracy of the trained observer measurements was comparable to the expert interobserver agreement and was better for absolute measurements and with three ROIs. The agreement between the one ROI and three ROI methods was good. Absolute thrombus density measurement has superior interobserver agreement compared to relative density measurement. Interobserver variation is smaller when multiple ROIs are used. Trained non-expert observers can accurately and reproducibly assess absolute thrombus densities using three ROIs. (orig.)

  7. The importance of risk-aversion as a measurable psychological parameter governing risk-taking behaviour

    Science.gov (United States)

    Thomas, P. J.

    2013-09-01

    A utility function with risk-aversion as its sole parameter is developed and used to examine the well-known psychological phenomenon, whereby risk averse people adopt behavioural strategies that are extreme and apparently highly risky. The pioneering work of the psychologist, John W. Atkinson, is revisited, and utility theory is used to extend his mathematical model. His explanation of the psychology involved is improved by regarding risk-aversion not as a discrete variable with three possible states: risk averse, risk neutral and risk confident, but as continuous and covering a large range. A probability distribution is derived, the "motivational density", to describe the process of selecting tasks of different degrees of difficulty. An assessment is then made of practicable methods for measuring risk-aversion.

  8. Tumour ADC measurements in rectal cancer: effect of ROI methods on ADC values and interobserver variability

    Energy Technology Data Exchange (ETDEWEB)

    Lambregts, Doenja M.J.; Maas, Monique [Maastricht University Medical Center, Department of Radiology, Maastricht (Netherlands); Maastricht University Medical Center, Department of Surgery, Maastricht (Netherlands); Beets, Geerard L. [Maastricht University Medical Center, Department of Surgery, Maastricht (Netherlands); Curvo-Semedo, Luis [Radiology University Clinic, Coimbra University Hospital, Department of Radiology, Coimbra (Portugal); Kessels, Alfons G.H. [Maastricht University Medical Center, Department of Epidemiology, Maastricht (Netherlands); Thywissen, Thomas; Beets-Tan, Regina G.H. [Maastricht University Medical Center, Department of Radiology, Maastricht (Netherlands)

    2011-12-15

    To assess the influence of region of interest (ROI) size and positioning on tumour ADC measurements and interobserver variability in patients with locally advanced rectal cancer (LARC). Forty-six LARC patients were retrospectively included. Patients underwent MRI including DWI (b0,500,1000) before and 6-8 weeks after chemoradiation (CRT). Two readers measured mean tumour ADCs (pre- and post-CRT) according to three ROI protocols: whole-volume, single-slice or small solid samples. The three protocols were compared for differences in ADC, SD and interobserver variability (measured as the intraclass correlation coefficient; ICC). ICC for the whole-volume ROIs was excellent (0.91) pre-CRT versus good (0.66) post-CRT. ICCs were 0.53 and 0.42 for the single-slice ROIs versus 0.60 and 0.65 for the sample ROIs. Pre-CRT ADCs for the sample ROIs were significantly lower than for the whole-volume or single-slice ROIs. Post-CRT there were no significant differences between the whole-volume ROIs and the single-slice or sample ROIs, respectively. The SDs for the whole-volume and single-slice ROIs were significantly larger than for the sample ROIs. ROI size and positioning have a considerable influence on tumour ADC values and interobserver variability. Interobserver variability is worse after CRT. ADCs obtained from the whole tumour volume provide the most reproducible results. (orig.)

  9. Importance of education and competence maintenance in metrology field (measurement science)

    Science.gov (United States)

    Dobiliene, J.; Meskuotiene, A.

    2015-02-01

    For certain tasks in metrology field trained employers might be necessary to fulfill specific requirements. It is important to pay attention that metrologists are responsible for fluent work of devices that belong to huge variety of vide spectrum of measurements. People who perform measurements (that are related to our safety, security or everyday life) with reliable measuring instruments must be sure for trueness of their results or conclusions. So with the purpose to reach the harmony between the ordinary man and his used means it is very important to ensure competence of specialists that are responsible for mentioned harmony implementation. Usually these specialists have a university degree and perform highly specified tasks in science, industry or laboratories. Their task is quite narrow. For example, type approval of measuring instrument or calibration and verification. Due to the fact that the number of such employers and their tasks is relatively small in the field of legal metrology, this paper focuses on the significance of training and qualification of legal metrology officers.

  10. Minimal Clinically Important Difference of Patient Reported Outcome Measures of Lower Extremity Injuries in Orthopedics

    Science.gov (United States)

    Çelik, Derya; Çoban, Özge; Kılıçoğlu, Önder

    2017-01-01

    Purpose: MCID scores for outcome measures are frequently used evidence-based guides to gage meaningful changes. To conduct a systematic review of the quality and content of the the minimal clinically important difference (MCID) relating to 16 patient-rated outcome measures (PROM) used in lower extremity. Methods: We conducted a systematic literature review on articles reporting MCID in lower extremity outcome measures and orthopedics from January 1, 1980, to May 10, 2016. We evaluated MCID of the 16 patient reported outcome measures (PROM) which were Harris Hip Score (HHS), Oxford Hip Score (OHS), Hip Outcome Score (HOS), Hip Disability and Osteoarthritis Outcome Score (HOOS), The International Knee Documentation Committee Subjective Knee Form (IKDC), The Lysholm Scale, The Western Ontario Meniscal Evaluation Tool (WOMET), The Anterior Cruciate Ligament Quality of Life Questionnaire (ACL-QOL), The Lower Extremity Functional Scale (LEFS), The Western Ontario and Mcmaster Universities Index (WOMAC), Knee İnjury And Osteoarthritis Outcome Score (KOOS), Oxford Knee Score (OKS), Kujala Anterior Knee Pain Scale, The Victorian Institute of Sports Assessment Patellar Tendinosis (Jumper’s Knee) (VİSA-P), Tegner Activity Rating Scale, Marx Activity Rating Scale, Foot And Ankle Outcome Score (FAOS), The Foot Function Index (FFI), Foot And Ankle Ability Measure (FAAM), The Foot And Ankle Disability Index Score and Sports Module, Achill Tendon Total Rupture Score(ATRS), The Victorian İnstitute Of Sports Assesment Achilles Questionnaire(VİSA-A), American Orthopaedic Foot and Ankle Society (AOFAS). A search of the PubMed/MEDLINE, PEDro and Cochrane Cen¬tral Register of Controlled Trials and Web of Science databases from the date of inception to May 1, 2016 was conducted. The terms “minimal clinically important difference,” “minimal clinically important change”, “minimal clinically important improvement” “were combined with one of the PROM as mentioned above

  11. Newborn Thyroid Screening: Influence of Pre-Analytic Variables on Dried Blood Spot Thyrotropin Measurement.

    Science.gov (United States)

    Butler, Allison M; Charoensiriwatana, Wiyada; Krasao, Piamnukul; Pankanjanato, Rotjanapan; Thong-Ngao, Penpan; Polson, Randall C; Snow, Gregory; Ehrenkranz, Joel

    2017-09-01

    Measuring thyrotropin (TSH) eluted from a dried blood spot (DBS) is used to screen an estimated 30 million newborns annually for congenital hypothyroidism (CH). Newborn thyroid screening has eliminated cretinism from the industrialized world and decreased the adverse effects of unrecognized CH on neurocognitive development. Hematocrit, a pre-analytic variable that affects the measurement of TSH from a DBS, contributes to the imprecision of DBS TSH measurement and could account for false-negative and false-positive DBS newborn screening test results. To assess whether variations in hematocrit found in newborns have a clinical effect in DBS-based newborn thyroid screening, the effects of hematocrit variability on the measurement of DBS TSH were studied. U.S. Centers for Disease Control and Prevention procedures for manufacturing DBS performance testing standards were used to generate DBSs from blood samples, with hematocrits of 35%, 40%, 45%, 50%, 55%, 60%, and 65% and serum TSH concentrations of 6.3 ± 0.4 and 26.6 ± 8.0 mIU/L. TSH was measured in the eluates of four replicate DBS 3 mm punches at each hematocrit using the Thailand Ministry of Public Health Newborn Screening Operation Center enzyme-linked immunosorbent assay. Data were analyzed using a linear mixed-effects model. Based on the mixed-effects model, hematocrit significantly affected DBS TSH measurement (p factors may improve the precision of DBS TSH measurement.

  12. Variability of Liver Shear Wave Measurements Using a New Ultrasound Elastographic Technique.

    Science.gov (United States)

    Nadebaum, David P; Nicoll, Amanda J; Sood, Siddharth; Gorelik, Alexandra; Gibson, Robert N

    2017-09-29

    A new 2-dimensional (2D) shear wave elastographic (SWE) device has been developed for the noninvasive assessment of liver fibrosis. Guidelines on measurement acquisition parameters are not yet well established for this technique. Our study aimed to assess 2D SWE measurement variability and to determine the number of measurements required per patient to reliably assess liver stiffness. Two-dimensional SWE was assessed in 55 patients with mixed-etiology chronic liver disease on an Aplio 500 ultrasound system (Toshiba Medical Systems Corporation, Tochigi, Japan). Ten measurements were obtained per patient by an operator blinded to all preceding readings. Results were analyzed with clinical information obtained from medical records. The median interquartile range/median ratio for 2D SWE was 0.131 (quartiles 1-3, 0.089-0.174). Five readings provided an approximation within 0.11 m/s, or 4.2% of the median velocity of 10 measurements. Factors associated with increased measurement variability included body mass index (ρ = 0.388; P = .01), increased skin-to-liver capsule distance (ρ = 0.426; P = .002), and measurements taken within 1.5 cm of the liver capsule (P  0.15) showed greater deviation from the set's median velocity than those with an ROI SD/speed ratio of 0.15 or lower (0.42 versus 0.22 m/s; P = .001). Two-dimensional SWE showed low overall measurement variability, with a minimum of 5 readings providing equivalent precision to the existing method using 10 samples. Obesity, increasing abdominal wall thickness, subcapsular measurements and an ROI SD/speed ratio of greater than 0.15 were all associated with increased measurement variability. The ROI SD/speed ratio warrants further evaluation as a quality assessment metric, to allow objective operator assessment of individual 2D SWE measurement reliability in real time. © 2017 by the American Institute of Ultrasound in Medicine.

  13. Intra-individual variability and continuity of action and perception measures in infants.

    Science.gov (United States)

    Gampe, Anja; Keitel, Anne; Daum, Moritz M

    2015-01-01

    The development of action and perception, and their relation in infancy is a central research area in socio-cognitive sciences. In this Perspective Article, we focus on the developmental variability and continuity of action and perception. At group level, these skills have been shown to consistently improve with age. We would like to raise awareness for the issue that, at individual level, development might be subject to more variable changes. We present data from a longitudinal study on the perception and production of contralateral reaching skills of infants aged 7, 8, 9, and 12 months. Our findings suggest that individual development does not increase linearly for action or for perception, but instead changes dynamically. These non-continuous changes substantially affect the relation between action and perception at each measuring point and the respective direction of causality. This suggests that research on the development of action and perception and their interrelations needs to take into account individual variability and continuity more progressively.

  14. Importance of Performance Measurement and MCH Epidemiology Leadership to Quality Improvement Initiatives at the National, State and Local Levels.

    Science.gov (United States)

    Rankin, Kristin M; Gavin, Loretta; Moran, John W; Kroelinger, Charlan D; Vladutiu, Catherine J; Goodman, David A; Sappenfield, William M

    2016-11-01

    Purpose In recognition of the importance of performance measurement and MCH epidemiology leadership to quality improvement (QI) efforts, a plenary session dedicated to this topic was presented at the 2014 CityMatCH Leadership and MCH Epidemiology Conference. This paper summarizes the session and provides two applications of performance measurement to QI in MCH. Description Performance measures addressing processes of care are ubiquitous in the current health system landscape and the MCH community is increasingly applying QI processes, such as Plan-Do-Study-Act (PDSA) cycles, to improve the effectiveness and efficiency of systems impacting MCH populations. QI is maximally effective when well-defined performance measures are used to monitor change. Assessment MCH epidemiologists provide leadership to QI initiatives by identifying population-based outcomes that would benefit from QI, defining and implementing performance measures, assessing and improving data quality and timeliness, reporting variability in measures throughout PDSA cycles, evaluating QI initiative impact, and translating findings to stakeholders. MCH epidemiologists can also ensure that QI initiatives are aligned with MCH priorities at the local, state and federal levels. Two examples of this work, one highlighting use of a contraceptive service performance measure and another describing QI for peripartum hemorrhage prevention, demonstrate MCH epidemiologists' contributions throughout. Challenges remain in applying QI to complex community and systems-level interventions, including those aimed at improving access to quality care. Conclusion MCH epidemiologists provide leadership to QI initiatives by ensuring they are data-informed and supportive of a common MCH agenda, thereby optimizing the potential to improve MCH outcomes.

  15. Relative Importance of Central and Peripheral Adiposities on Cardiometabolic Variables in Females: A Japanese Population-Based Study.

    Science.gov (United States)

    Kouda, Katsuyasu; Dongmei, Namiraa; Tamaki, Junko; Iki, Masayuki; Tachiki, Takahiro; Kajita, Etsuko; Nakatani, Yoshimi; Uenishi, Kazuhiro; Kagamimori, Sadanobu; Kagawa, Yoshiko; Yoneshima, Hideo

    In epidemiological studies, there is little evidence regarding the relative impact of central adiposity and peripheral adiposity on cardiometabolic risk factors, especially in Asian populations. This study investigated associations between central-to-peripheral fat ratios and cardiometabolic variables using data from a population-based study of Japanese women. The source population was composed of 1800 women aged 50 yr or older at the 15th- to 16th-yr follow-up survey of the Japanese Population-Based Osteoporosis Cohort Study. This study analyzed cross-sectional data from 998 women for whom complete information about body fat variables according to dual-energy X-ray absorptiometry, cardiometabolic variables, and potential confounding factors was available. Both before and after adjusting for potential confounding factors, trunk-to-appendicular fat ratios showed significant (p variables were independent of relationships between fat volumes (in whole body or in trunk) and cardiometabolic variables. Furthermore, relationships between trunk-to-appendicular fat ratios and cardiometabolic variables were observed among women in the lowest tertile of total body fat (brachial-ankle pulse wave velocity, β = 0.08; high-density lipoprotein cholesterol, β = -0.32; low-density lipoprotein cholesterol, β = 0.15; and hemoglobin A1C, β = 0.16; p variables than peripheral adiposity. Information on central-to-peripheral fat ratios is particularly valuable for the evaluation of relatively thin Japanese women. Copyright © 2016 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  16. Uncertainty Quantification Reveals the Importance of Data Variability and Experimental Design Considerations for in Silico Proarrhythmia Risk Assessment.

    Science.gov (United States)

    Chang, Kelly C; Dutta, Sara; Mirams, Gary R; Beattie, Kylie A; Sheng, Jiansong; Tran, Phu N; Wu, Min; Wu, Wendy W; Colatsky, Thomas; Strauss, David G; Li, Zhihua

    2017-01-01

    The Comprehensive in vitro Proarrhythmia Assay (CiPA) is a global initiative intended to improve drug proarrhythmia risk assessment using a new paradigm of mechanistic assays. Under the CiPA paradigm, the relative risk of drug-induced Torsade de Pointes (TdP) is assessed using an in silico model of the human ventricular action potential (AP) that integrates in vitro pharmacology data from multiple ion channels. Thus, modeling predictions of cardiac risk liability will depend critically on the variability in pharmacology data, and uncertainty quantification (UQ) must comprise an essential component of the in silico assay. This study explores UQ methods that may be incorporated into the CiPA framework. Recently, we proposed a promising in silico TdP risk metric (qNet), which is derived from AP simulations and allows separation of a set of CiPA training compounds into Low, Intermediate, and High TdP risk categories. The purpose of this study was to use UQ to evaluate the robustness of TdP risk separation by qNet. Uncertainty in the model parameters used to describe drug binding and ionic current block was estimated using the non-parametric bootstrap method and a Bayesian inference approach. Uncertainty was then propagated through AP simulations to quantify uncertainty in qNet for each drug. UQ revealed lower uncertainty and more accurate TdP risk stratification by qNet when simulations were run at concentrations below 5× the maximum therapeutic exposure (Cmax). However, when drug effects were extrapolated above 10× Cmax, UQ showed that qNet could no longer clearly separate drugs by TdP risk. This was because for most of the pharmacology data, the amount of current block measured was design considerations that preclude an accurate determination of drug IC50-values in vitro. Thus, we demonstrate that UQ provides valuable information about in silico modeling predictions that can inform future proarrhythmic risk evaluation of drugs under the CiPA paradigm.

  17. Measurement variability of quantitative sensory testing in persons with post-stroke shoulder pain.

    Science.gov (United States)

    Lindgren, Ingrid; Ekstrand, Elisabeth; Brogårdh, Christina

    2016-04-28

    To evaluate the measurement variability of quantitative sensory testing (QST) in persons with post-stroke shoulder pain. A test-retest design. Twenty-three persons with post-stroke shoulder pain (median age 65 years). Thermal detection thresholds (cold and warm), pain thresholds (cold and heat) and mechanical pain thresholds (pressure and pin prick) were assessed twice in both arms, 2-3 weeks apart. Measurement variability was analysed with the intraclass correlation coefficient (ICC2.1), the change in mean (đ) with 95% confidence interval (logarithmic scales), and the relative standard error of measurement (SEM%; re-transformed scales). The ICCs for thermal thresholds ranged from 0.48 to 0.89 in the affected (painful) arm and from 0.50 to 0.63 in the unaffected arm, and for mechanical pain thresholds from 0.66 to 0.90 in both arms. No systematic changes in the mean (đ) were found. The SEM% ranged from 4% to 10% for thermal detection and heat pain thresholds, and from 17% to 42% for cold pain and mechanical pain thresholds in both arms. QST measurements, especially cold pain thresholds and mechanical pain thresholds, vary in persons with post-stroke shoulder pain. Before QST can be used routinely to evaluate post-stroke shoulder pain, a test protocol with decreased variability needs to be developed.

  18. Variability in Measures of Exhaled Breath Na, Influence of pulmonary Blood Flow and salivary Na

    Directory of Open Access Journals (Sweden)

    Courtney M. Wheatley

    2010-04-01

    Full Text Available The assessment of inflammatory markers and ions in exhaled breath condensate (EBC is being utilized more frequently in diseases such as asthma and cystic fibrosis with marked variability in EBC measures, including those of exhaled Na + . We sought to determine if variability in exhaled Na + was due to differences in pulmonary blood flow (PBF or Na + in the mouth (salivary Na + . We measured exhaled Na + three times with coinciding sampling of salivary Na + and assessment of PBF (using acetylene rebreathing in 13 healthy subjects (54% female, age = 27 ± 7 yrs., ht. = 172 ± 10 cm, wt. = 70 ± 21 kg, BMI = 22 ± 7 kg/m 2 mean ± SD. Exhaled Na + averaged 2.7 ± 1.2 mmol/l, and salivary Na + averaged 5.51 ± 4.58 mmol/l. The coefficients of variation across all three measures in all 13 subjects averaged 30% for exhaled Na + and 83% for salivary Na + , within subjects the variability across the three measures averaged 30% for exhaled Na + and 38% for salivary Na + . Across all three measures in all 13 subjects the relationship between PBF and exhaled Na + averaged 0.027 ( P = 0.87, and the relationship between salivary Na + and exhaled Na + concentrations averaged 0.59 ( P = 0.001. Also, we sought to determine the relationship between exhaled Na + and serum Na + in an addition 20 subjects. There was a moderate and significant relationship between serum Na + and exhaled Na + (r = 0.37, P = 0.04. These findings suggest there that the variability in exhaled Na + is caused, at least in part, by droplet formation from within the mouth as turbulent air passes through and that there is a flux of ions from the pulmonary blood into the airways.

  19. Googling food webs: can an eigenvector measure species' importance for coextinctions?

    Science.gov (United States)

    Allesina, Stefano; Pascual, Mercedes

    2009-09-01

    A major challenge in ecology is forecasting the effects of species' extinctions, a pressing problem given current human impacts on the planet. Consequences of species losses such as secondary extinctions are difficult to forecast because species are not isolated, but interact instead in a complex network of ecological relationships. Because of their mutual dependence, the loss of a single species can cascade in multiple coextinctions. Here we show that an algorithm adapted from the one Google uses to rank web-pages can order species according to their importance for coextinctions, providing the sequence of losses that results in the fastest collapse of the network. Moreover, we use the algorithm to bridge the gap between qualitative (who eats whom) and quantitative (at what rate) descriptions of food webs. We show that our simple algorithm finds the best possible solution for the problem of assigning importance from the perspective of secondary extinctions in all analyzed networks. Our approach relies on network structure, but applies regardless of the specific dynamical model of species' interactions, because it identifies the subset of coextinctions common to all possible models, those that will happen with certainty given the complete loss of prey of a given predator. Results show that previous measures of importance based on the concept of "hubs" or number of connections, as well as centrality measures, do not identify the most effective extinction sequence. The proposed algorithm provides a basis for further developments in the analysis of extinction risk in ecosystems.

  20. Googling food webs: can an eigenvector measure species' importance for coextinctions?

    Directory of Open Access Journals (Sweden)

    Stefano Allesina

    2009-09-01

    Full Text Available A major challenge in ecology is forecasting the effects of species' extinctions, a pressing problem given current human impacts on the planet. Consequences of species losses such as secondary extinctions are difficult to forecast because species are not isolated, but interact instead in a complex network of ecological relationships. Because of their mutual dependence, the loss of a single species can cascade in multiple coextinctions. Here we show that an algorithm adapted from the one Google uses to rank web-pages can order species according to their importance for coextinctions, providing the sequence of losses that results in the fastest collapse of the network. Moreover, we use the algorithm to bridge the gap between qualitative (who eats whom and quantitative (at what rate descriptions of food webs. We show that our simple algorithm finds the best possible solution for the problem of assigning importance from the perspective of secondary extinctions in all analyzed networks. Our approach relies on network structure, but applies regardless of the specific dynamical model of species' interactions, because it identifies the subset of coextinctions common to all possible models, those that will happen with certainty given the complete loss of prey of a given predator. Results show that previous measures of importance based on the concept of "hubs" or number of connections, as well as centrality measures, do not identify the most effective extinction sequence. The proposed algorithm provides a basis for further developments in the analysis of extinction risk in ecosystems.

  1. Pneumophonic coordination impairments in parkinsonian dysarthria: importance of aerodynamic parameters measurements.

    Science.gov (United States)

    Moustapha, S M; Alain, G; Robert, E; Bernard, T; Mourtalla, Kâ M; Lamine, G; François, V

    2012-01-01

    Among Parkinsonian axial signs, dysarthria represents an important disabling symptom able to lead towards a significant reduction of oral communication. Several methods of dysarthria assessment have been used but aerodynamic evaluation is rare in the literature. To highlight the importance of aerodynamic parameters measurements in assessment of parkinsonian dysarthria. Using a dedicated system (EVA2), 24 parkinsonian patients were recorded after withdrawal of L-dopa for at least 12 h (condition called OFF DOPA) in order to evaluate intra-oral pressure (IOP), mean oral air flow (MOAF) and laryngeal resistance (LR) on six /p/ during realization of the sentence "Papa ne m'a pas parle' de beau-papa" ("Daddy did not speak to me about daddy-in-law") which corresponds to a breath group. 50 control subjects were recorded in parallel in order to define reference measurements. It appeared that there is in Parkinson's disease aerodynamic impairments which were evidenced by the fall in IOP and that of MOAF in patients compared with control subjects. The difference between the two groups was statistically significant. In addition a greater instability of LR in patients compared with control subjects was also noted. Our results show that measurements of aerodynamics parameters, by reflecting the dysfunction induced by disease, may well be relevant factors in parkinsonian dysarthria evaluation.

  2. Association between different measurements of blood pressure variability by ABP monitoring and ankle-brachial index

    Directory of Open Access Journals (Sweden)

    Moreira Leila B

    2010-11-01

    Full Text Available Abstract Background Blood pressure (BP variability has been associated with cardiovascular outcomes, but there is no consensus about the more effective method to measure it by ambulatory blood pressure monitoring (ABPM. We evaluated the association between three different methods to estimate BP variability by ABPM and the ankle brachial index (ABI. Methods and Results In a cross-sectional study of patients with hypertension, BP variability was estimated by the time rate index (the first derivative of SBP over time, standard deviation (SD of 24-hour SBP; and coefficient of variability of 24-hour SBP. ABI was measured with a doppler probe. The sample included 425 patients with a mean age of 57 ± 12 years, being 69.2% women, 26.1% current smokers and 22.1% diabetics. Abnormal ABI (≤ 0.90 or ≥ 1.40 was present in 58 patients. The time rate index was 0.516 ± 0.146 mmHg/min in patients with abnormal ABI versus 0.476 ± 0.124 mmHg/min in patients with normal ABI (P = 0.007. In a logistic regression model the time rate index was associated with ABI, regardless of age (OR = 6.9, 95% CI = 1.1- 42.1; P = 0.04. In a multiple linear regression model, adjusting for age, SBP and diabetes, the time rate index was strongly associated with ABI (P Conclusion Time rate index is a sensible method to measure BP variability by ABPM. Its performance for risk stratification of patients with hypertension should be explored in longitudinal studies.

  3. Bone marrow content measured in radioimmune bone marrow scintigraphy: intra- and inter-observer variability.

    Science.gov (United States)

    Roland, J; Brans, B; Vervaet, A; Goor, C; Servais, J; de Meyere, P; van den Wijngaert, D; Vandevivere, J; Scalliet, P

    1999-05-01

    The aim of this study was to assess the possible quantification of vertebral residual bone marrow content relative to the bone marrow content of a non-irradiated vertebra. This method is based on the vertebral count activity, measured using radioimmune bone marrow scintigraphy. First, however, we had to evaluate intra- and inter-observer variability. In three patients who underwent radioimmune bone marrow scintigraphy, two independent observers measured the count density in 51 (15 lumbar and 36 thoracic) vertebrae using a manually drawn region of interest. To evaluate intra- and inter-observer variability, we calculated the means and standard deviations of the differences between measurements. Bland-Altman plots were drawn for all vertebrae as well as for three subgroups of vertebrae (the upper thoracic spine, D1-D6; the lower thoracic spine, D7-D12; and the lumber spine, L1-L5). For all vertebrae, the mean (+/- S.D.) difference, expressed as a percentage of the overall mean, was -0.44 +/- 3.3% for observer 1 and -0.3 +/- 2.1% for observer 2 for intra-observer variability; inter-observer variability varied from 0.55 +/- 3.9% to 1.28 +/- 3.7%. On the Bland-Altman plots, the data points were evenly distributed above and below the 0-line and the linear regression equations matched the line of equality almost perfectly. This pattern was observed for all the vertebrae as well as for the subgroups of vertebrae. In conclusion, our results show that the intra- and inter-observer variabilities are not great, confirming that this technique is simple and robust and can be used for further quantification of bone marrow content in the axial skeleton.

  4. Increased accuracy through variable-baseline gradient measurements with superconducting gravimeters

    Science.gov (United States)

    Kennedy, J.; Ferre, T. P.; Abe, M.; Guntner, A.

    2013-12-01

    Despite the availability of sub-microgal superconducting gravimeters for many years, precise measurements of gravity change are still limited by our ability to resolve the signal of interest. Errors in Earth tide, ocean loading, and atmospheric corrections can obscure signals of interest for applications in hydrology, reservoir management, CO2 sequestration, volcanology, and other studies. Errors are largest for instruments deployed in new locations for short durations, in which case loading-model parameters must be determined a priori to calculate gravity residuals. Without better models or improved methods to remove unwanted signals, more accurate gravimeters provide limited benefit. One way to remove unwanted signals is to make 'variable-baseline gravity gradient' measurements using two (or more) gravimeters. With two gravimeters located in close proximity, common-mode signals that affect both instruments equally, such as Earth tides, ocean loading, and atmospheric changes, are removed from the differenced signal - essentially, this creates an average, single-tensor gradient measurement over the baseline separating the gravimeters. In winter 2012, such a variable-baseline gradient measurement was made for the first time adjacent to an artificial recharge basin in Arizona, USA. One of two iGrav gravimeters was deployed inside a newly-developed field enclosure, demonstrating that such instruments can be deployed for short periods with little preparation. The difference between the two instruments could be resolved to better than 0.3 microgals per day. As compared to the single-instrument signal, the gradient measurement better resolved the timing of the onset of infiltration and the depth of the wetting front beneath the basin over time. Furthermore, by varying the position of the two gravimeters, the measurement can be 'focused' at a specific depth. Making variable-baseline gravity gradient measurements can provide improved accuracy and sensitivity using today

  5. Identification of voltage stability condition of a power system using measurements of bus variables

    Directory of Open Access Journals (Sweden)

    Durlav Hazarika

    2014-12-01

    Full Text Available Several online methods were proposed for investigating the voltage stability condition of an interconnected power system using the measurements of voltage and current phasors at a bus. For this purpose, phasor measurement units (PMUs are used. A PMU is a device which measures the electrical waves on an electrical network, using a common time source (reference bus for synchronisation. This study proposes a method for online monitoring of voltage stability condition of a power system using measurements of bus variables namely – (i real power, (ii reactive power and (iii bus voltage magnitude at a bus. The measurements of real power, reactive power and bus voltage magnitude could be extracted/captured from a smart energy meter. The financial involvement for implementation of the proposed method would significantly lower compared with the PMU-based method.

  6. Heart Rate Variability as a Measure of Disease State in Irritable Bowel Syndrome

    Directory of Open Access Journals (Sweden)

    Hyo-Jung Park, RN, PhD

    2008-03-01

    Full Text Available Heart rate variability (HRV is a noninvasive measure of sympathovagal balance in the autonomic nervous system (ANS. This review will: (a consider HRV measurement in irritable bowel syndrome (IBS; (b discuss the applicability of HRV measurement in IBS by addressing strengths and limitations; and (c propose future directions in this field of gastrointestinal research and clinical practice. As a strength, analyzing HRV components is a useful method and appears most suitable for detection of changes in ANS sympathovagal balance in both stress and non-stress conditions with good validity and reliability. Also, it is an appropriate measure for ANS in studies with large populations, in both laboratory and clinical settings, and for longitudinal studies because of its noninvasive assets. With regard to limitations of measuring HRV, these are poor standardization, additional human editing, not considering medication or other confounding factors, inconsistent results in gastrointestinal vagal tone study, and different time periods.

  7. Thymic measurements in pathologically proven normal thymus and thymic hyperplasia: intraobserver and interobserver variabilities.

    Science.gov (United States)

    Araki, Tetsuro; Sholl, Lynette M; Gerbaudo, Victor H; Hatabu, Hiroto; Nishino, Mizuki

    2014-06-01

    To determine the intraobserver and interobserver variabilities of thymic measurements on computed tomography (CT) in patients with pathologic diagnosis of thymic hyperplasia or normal thymus. Thirty-three patients with pathologic diagnosis of thymic hyperplasia (n = 25) or normal thymus (n = 8) who had identifiable thymus gland on CT were retrospectively studied. Two radiologists independently measured thymic size and CT attenuation. Concordance correlation coefficients (CCCs) and Bland-Altman plots were used to assess intraobserver and interobserver agreements. The intraobserver and interobserver agreements of thymic diameters and the lobe length were moderate, with CCCs ranging from 0.73 to 0.89 and from 0.72 to 0.81, respectively. Higher agreement was noted among patients whose measurements were performed on the same CT image in two independent measurements, with intraobserver CCC ≥ 0.95 for diameters and length. After providing readers with an instruction for consistent selection of CT image for measurements, the intraobserver and interobserver agreements improved, resulting in CCCs ranging from 0.81 to 0.92 and from 0.77 to 0.85 for diameters and length, respectively. Thymic lobe thickness had the least agreement. CT attenuation measurements were highly reproducible, with CCCs ranging from 0.88 to 0.97. In patients with thymic CT attenuation >30 HU (Hounsfield unit), the attenuation measurements were more reproducible with narrower 95% limits of agreement. Thymic size measurements had moderate-to-high intraobserver and interobserver agreements, when the instruction for consistent selection of images was provided to the readers. CT attenuation was highly reproducible, with higher reproducibility for thymic glands with >30 HU. Awareness of thymic measurement variability is necessary when interpreting measured values of normal thymus and thymic pathology on CT. Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.

  8. Thymic measurements in pathologically proven normal thymus and thymic hyperplasia: Intra- and interobserver variability

    Science.gov (United States)

    Araki, Tetsuro; Sholl, Lynette M.; Gerbaudo, Victor H.; Hatabu, Hiroto; Nishino, Mizuki

    2014-01-01

    Objective: Determine the intra- and interobserver variability of thymic measurements on computed tomography (CT) in patients with pathological diagnosis of thymic hyperplasia or normal thymus. Materials and Methods: Thirty-three patients with pathological diagnosis of thymic hyperplasia (n=25) or normal thymus (n=8) who had identifiable thymus gland on CT were retrospectively studied. Two radiologists independently measured thymic size and CT attenuation. Concordance correlation coefficients (CCCs) and Bland-Altman plots were used to assess intra- and interobserver agreements. Results: The intra- and interobserver agreements of thymic diameters and the lobe length were moderate, with CCCs ranging 0.73-0.89 and 0.72-0.81, respectively. Higher agreement was noted among patients whose measurements were performed on the same CT image in two independent measurements, with intraobserver CCC ≥0.95 for diameters and length. After providing readers with an instruction for consistent selection of CT image for measurements, the intra- and interobserver agreement improved, resulting in CCCs ranging 0.81-0.92 and 0.77-0.85 for diameters and length, respectively. Thymic lobe thickness had the least agreement. CT attenuation measurements were highly reproducible, with CCCs ranging 0.88-0.97. In patients with thymic CT attenuation >30HU, the attenuation measurements were more reproducible with narrower 95% limits of agreement. Conclusion: Thymic size measurements had moderate to high intra- and interobserver agreement, when the instruction for consistent selection of images were provided to the readers. CT attenuation was highly reproducible, with higher reproducibility for thymic glands with >30HU. Awareness of thymic measurement variability is necessary when interpreting measured values of normal thymus and thymic pathology on CT. PMID:24809315

  9. Measured Deformation Enhancement in Western Greenland Shows the Importance of Viscosity Reduction for Elevated Melt Season Velocities

    Science.gov (United States)

    Maier, N. T.; Humphrey, N. F.; Harper, J. T.; Meierbachtol, T. W.

    2016-12-01

    There is increasing evidence that much of the bed on the Western Margin of the Greenland Ice Sheet (GrIS) is hydrologically isolated during the melt season, making it necessary to understand how ice dynamics regulates basal flow between active and inactive regions of the bed. We present measurements of englacial shear strain rates collected by tilt sensors embedded in a boreholes approximately 670 m deep during the 2015 melt season at a field site on the Western Margin of the GrIS. The measurements demonstrate that shear strain rates during the melt season can increase by a factor of three. The increase in shear strain rates and deformation velocity is well correlated to the surface and basal sliding velocity measured at the field site. Coincident with the enhanced deformation, the effective stress calculated from the surficial strain rate tensor increases from approximately 70-160 kPa. During this period each stress component shows a high degree of variability. The magnitude and range of the effective stress is in agreement with the change in the effective stress necessary to produce the elevated strain rates observed englacially. This result demonstrates that spatially variable flow at the onset of the melt season can result in a significant decrease in the effective ice viscosity. The decrease in the effective ice viscosity is sufficient to increase the deformation velocity from approximately 20 to 40 ma-1. The increase in the deformation velocity is well correlated to the observed increase in basal sliding suggesting that ice softening may be an important mechanism to enhance basal flow in isolated regions of the bed. For a glacier on a hard bed, the rate of basal sliding is controlled by the rate at which the basal ice can deform around bedrock obstacles. In this context, a reduction in the effective viscosity can enhance the basal sliding velocity without a basal friction reduction through local changes in basal water pressure or water storage.

  10. The importance of optical methods for non-invasive measurements in the skin care industry

    Science.gov (United States)

    Stamatas, Georgios N.

    2010-02-01

    Pharmaceutical and cosmetic industries are concerned with treating skin disease, as well as maintaining and promoting skin health. They are dealing with a unique tissue that defines our body in space. As such, skin provides not only the natural boundary with the environment inhibiting body dehydration as well as penetration of exogenous aggressors to the body, it is also ideally situated for optical measurements. A plurality of spectroscopic and imaging methods is being used to understand skin physiology and pathology and document the effects of topically applied products on the skin. The obvious advantage of such methods over traditional biopsy techniques is the ability to measure the cutaneous tissue in vivo and non-invasively. In this work, we will review such applications of various spectroscopy and imaging methods in skin research that is of interest the cosmetic and pharmaceutical industry. Examples will be given on the importance of optical techniques in acquiring new insights about acne pathogenesis and infant skin development.

  11. Gait stability and variability measures show effects of impaired cognition and dual tasking in frail people

    Directory of Open Access Journals (Sweden)

    de Vries Oscar J

    2011-01-01

    Full Text Available Abstract Background Falls in frail elderly are a common problem with a rising incidence. Gait and postural instability are major risk factors for falling, particularly in geriatric patients. As walking requires attention, cognitive impairments are likely to contribute to an increased fall risk. An objective quantification of gait and balance ability is required to identify persons with a high tendency to fall. Recent studies have shown that stride variability is increased in elderly and under dual task condition and might be more sensitive to detect fall risk than walking speed. In the present study we complemented stride related measures with measures that quantify trunk movement patterns as indicators of dynamic balance ability during walking. The aim of the study was to quantify the effect of impaired cognition and dual tasking on gait variability and stability in geriatric patients. Methods Thirteen elderly with dementia (mean age: 82.6 ± 4.3 years and thirteen without dementia (79.4 ± 5.55 recruited from a geriatric day clinic, walked at self-selected speed with and without performing a verbal dual task. The Mini Mental State Examination and the Seven Minute Screen were administered. Trunk accelerations were measured with an accelerometer. In addition to walking speed, mean, and variability of stride times, gait stability was quantified using stochastic dynamical measures, namely regularity (sample entropy, long range correlations and local stability exponents of trunk accelerations. Results Dual tasking significantly (p Conclusions The observed trunk adaptations were a consistent instability factor. These results support the concept that changes in cognitive functions contribute to changes in the variability and stability of the gait pattern. Walking under dual task conditions and quantifying gait using dynamical parameters can improve detecting walking disorders and might help to identify those elderly who are able to adapt walking

  12. Gait stability and variability measures show effects of impaired cognition and dual tasking in frail people.

    Science.gov (United States)

    Lamoth, Claudine J; van Deudekom, Floor J; van Campen, Jos P; Appels, Bregje A; de Vries, Oscar J; Pijnappels, Mirjam

    2011-01-17

    Falls in frail elderly are a common problem with a rising incidence. Gait and postural instability are major risk factors for falling, particularly in geriatric patients. As walking requires attention, cognitive impairments are likely to contribute to an increased fall risk. An objective quantification of gait and balance ability is required to identify persons with a high tendency to fall. Recent studies have shown that stride variability is increased in elderly and under dual task condition and might be more sensitive to detect fall risk than walking speed. In the present study we complemented stride related measures with measures that quantify trunk movement patterns as indicators of dynamic balance ability during walking. The aim of the study was to quantify the effect of impaired cognition and dual tasking on gait variability and stability in geriatric patients. Thirteen elderly with dementia (mean age: 82.6 ± 4.3 years) and thirteen without dementia (79.4 ± 5.55) recruited from a geriatric day clinic, walked at self-selected speed with and without performing a verbal dual task. The Mini Mental State Examination and the Seven Minute Screen were administered. Trunk accelerations were measured with an accelerometer. In addition to walking speed, mean, and variability of stride times, gait stability was quantified using stochastic dynamical measures, namely regularity (sample entropy, long range correlations) and local stability exponents of trunk accelerations. Dual tasking significantly (p dual task conditions. The observed trunk adaptations were a consistent instability factor. These results support the concept that changes in cognitive functions contribute to changes in the variability and stability of the gait pattern. Walking under dual task conditions and quantifying gait using dynamical parameters can improve detecting walking disorders and might help to identify those elderly who are able to adapt walking ability and those who are not and thus are at

  13. An exploration of extra and classroom variables for three measures of college mathematics achievement

    OpenAIRE

    Jamison, Margaret Godwin

    1994-01-01

    This study was an exploration into the effects of four categories of extra-student variables: high school performance, demographic characteristics, Myers-Briggs personality preferences and mathematics attitudes on three measures of college mathematics achievement (a Problem-Solving Test, an Algebra Skills Final Examination and course grade for all seven classes of 175 undergraduate students taking Pre-Calculus I Fall semester 1993). High school performance explained the most...

  14. Heart Rate Variability as a Measure of Airport Ramp-Traffic Controllers Workload

    Science.gov (United States)

    Hayashi, Miwa; Dulchinos, Victoria Lee

    2016-01-01

    Heart Rate Variability (HRV) has been reported to reflect the person's cognitive and emotional stress levels, and may offer an objective measure of human-operator's workload levels, which are recorded continuously and unobtrusively to the task performance. The present paper compares the HRV data collected during a human-in-the-loop simulation of airport ramp-traffic control operations with the controller participants' own verbal self-reporting ratings of their workload.

  15. The minimal important difference for measures of urticaria disease activity: Updated findings.

    Science.gov (United States)

    Mathias, Susan D; Crosby, Ross D; Rosén, Karin E; Zazzali, James L

    2015-01-01

    The Urticaria Patient Daily Diary (UPDD) is a validated patient-reported outcome that captures key measures of urticaria disease activity. To update estimates of the minimal important difference (MID) for urticaria disease activity measures in the UPDD, including the weekly itch severity score, weekly number of hives score, weekly average size of largest hive score, and the composite measure of itch severity and number of hives over 7 days, or urticaria activity score 7 (UAS7). A total of 975 subjects with chronic idiopathic urticaria from three randomized, double-blind, placebo-controlled studies completed the UPDD and other patient-reported outcome assessments (the Dermatology Life Quality Index, Medical Outcomes Study Sleep Scale, the Chronic Urticaria Quality-of-Life Questionnaire, the EuroQoL-5 Dimension Questionnaire) multiple times. MIDs were estimated through a combination of distribution- and anchor-based methods. MID estimates ranged from 4.5 to 5.0 for the weekly itch severity score, 5.0 to 5.5 for weekly hives count score, 9.5 to 10.5 for the UAS7, and 4.0 to 4.5 for the weekly size of the largest hive score. This analysis provided confirmation of the previous MID estimates for the urticaria disease activity measures in the UPDD.

  16. Control of environmental variables on species density in fens and meadows: importance of direct effects and effects through community biomass

    NARCIS (Netherlands)

    Olde Venterink, H.; Wassen, M.J.; Belgers, J.D.M.; Verhoeven, J.T.A.

    2001-01-01

    1. We tested whether patterns of species density are controlled not only by variations in community biomass but also by variations in environmental conditions, which may be related or unrelated to community biomass. Environmental variables (soil characteristics, acidity, water regime, nutrient

  17. Imported brucellosis in Denmark: Molecular identification and multiple-locus variable number tandem repeat analysis (MLVA) genotyping of the bacteria

    DEFF Research Database (Denmark)

    Aftab, H.; Dargis, R.; Christensen, J. J.

    2011-01-01

    A polymerase chain reaction was used to identify Brucella species isolated from humans in Denmark. Consecutive analysis of referred bacteria and re-examination of historical isolates identified all as Brucella melitensis. Multiple-locus variable number tandem repeat analysis (MLVA) placed...

  18. Fault-tolerant measurement-based quantum computing with continuous-variable cluster states.

    Science.gov (United States)

    Menicucci, Nicolas C

    2014-03-28

    A long-standing open question about Gaussian continuous-variable cluster states is whether they enable fault-tolerant measurement-based quantum computation. The answer is yes. Initial squeezing in the cluster above a threshold value of 20.5 dB ensures that errors from finite squeezing acting on encoded qubits are below the fault-tolerance threshold of known qubit-based error-correcting codes. By concatenating with one of these codes and using ancilla-based error correction, fault-tolerant measurement-based quantum computation of theoretically indefinite length is possible with finitely squeezed cluster states.

  19. Effect of pre-analytic variables on the reproducibility of qPCR relative telomere length measurement.

    Directory of Open Access Journals (Sweden)

    Casey L Dagnall

    Full Text Available Telomeres, long nucleotide repeats and a protein complex at chromosome ends, shorten with each cell division and are susceptible to oxidative damage. Quantitative PCR (qPCR is a widely-used technique to measure relative telomere length (RTL in DNA samples but is challenging to optimize and significant lab-to-lab variability has been reported. In this study, we evaluated factors that may contribute to qPCR RTL measurement variability including DNA extraction methods, methods used for removing potential residual PCR inhibitors, sample storage conditions, and sample location in the PCR plate. Our results show that the DNA extraction and purification techniques, as well as sample storage conditions introduce significant variability in qPCR RTL results. We did not find significant differences in results based on sample location in the PCR plate or qPCR instrument used. These data suggest that lack of reproducibility in published association studies of RTL could be, in part, due to methodological inconsistencies. This study illustrates the importance of uniform sample handling, from DNA extraction through data generation and analysis, in using qPCR to determine RTL.

  20. Variability in baseline laboratory measurements of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

    Science.gov (United States)

    Ladwig, R; Vigo, A; Fedeli, L M G; Chambless, L E; Bensenor, I; Schmidt, M I; Vidigal, P G; Castilhos, C D; Duncan, B B

    2016-08-01

    Multi-center epidemiological studies must ascertain that their measurements are accurate and reliable. For laboratory measurements, reliability can be assessed through investigation of reproducibility of measurements in the same individual. In this paper, we present results from the quality control analysis of the baseline laboratory measurements from the ELSA-Brasil study. The study enrolled 15,105 civil servants at 6 research centers in 3 regions of Brazil between 2008-2010, with multiple biochemical analytes being measured at a central laboratory. Quality control was ascertained through standard laboratory evaluation of intra- and inter-assay variability and test-retest analysis in a subset of randomly chosen participants. An additional sample of urine or blood was collected from these participants, and these samples were handled in the same manner as the original ones, locally and at the central laboratory. Reliability was assessed with the intraclass correlation coefficient (ICC), estimated through a random effects model. Coefficients of variation (CV) and Bland-Altman plots were additionally used to assess measurement variability. Laboratory intra and inter-assay CVs varied from 0.86% to 7.77%. From test-retest analyses, the ICCs were high for the majority of the analytes. Notably lower ICCs were observed for serum sodium (ICC=0.50; 95%CI=0.31-0.65) and serum potassium (ICC=0.73; 95%CI=0.60-0.83), due to the small biological range of these analytes. The CVs ranged from 1 to 14%. The Bland-Altman plots confirmed these results. The quality control analyses showed that the collection, processing and measurement protocols utilized in the ELSA-Brasil produced reliable biochemical measurements.

  1. Inter-observer Variability in Esophageal Body Measurements with High Resolution Manometry among New Physician Users

    Science.gov (United States)

    Singh, Erick; Rife, Christopher; Clayton, Steven; Naas, Peter; Nietert, Paul; Castell, Donald

    2012-01-01

    Goals To evaluate inter-observer variability among four new physician users on measures of esophageal body function. Background Esophageal high resolution manometry (HRM) allows observation of esophageal motility via pressure topography plots. Little is known about the inter-observer variability among physicians. Study Two resident and two fellow level physicians each interpreted 10 liquid swallows of 20 esophageal HRM studies (n=200 swallows) using the BioVIEW Analysis Suite (Sandhill Scientific, Inc.). Studies evaluated were from patients referred for evaluation of dysphagia but found to have normal esophageal manometry and complete liquid bolus transit. Physicians received an orientation session and reviewed recent literature. Each physician recorded contractile front velocity (CFV) and distal contractile integral (DCI) for each liquid swallow. STATISTICS: Inter-observer agreements for CFV and DCI were assessed by intraclass correlation (ICC) values. Linear correlations between measurements by two readers were assessed using linear regression modeling techniques. Results CFV and DCI values of up to 200 data points were analyzed. Four reader results for CFV and DCI showed strong agreement although stronger for DCI measures (ICC=0.94; 0.91 - 0.98) in comparison to CFV (ICC=0.79; 0.52 - 0.82). Further correlation was performed with two readers; readers 1 and 2 revealed excellent correlation for DCI (r=0.95, p<0.001) and good correlation for CFV (r=0.61, p<0.001). Conclusions With a thorough orientation session, good to excellent agreement for CFV and DCI measurements can be obtained from new physician users. CFV measures exhibit greater inter-observer variability possibly due to the artifact produced by intraesophageal pressurization. PMID:22647828

  2. Focusing on glaucoma progression and the clinical importance of progression rate measurement: a review.

    Science.gov (United States)

    Rossetti, L; Goni, F; Denis, P; Bengtsson, B; Martinez, A; Heijl, A

    2010-10-01

    This review aims to provide guidance in managing glaucoma patients more effectively. It focuses on the importance of detecting progression and measuring its rate within the management of primary open-angle glaucoma today. Recent findings strongly indicate that continued monitoring of visual fields (VFs) and reassessment of target intraocular pressures (IOPs) depending on VF progression rates are mandatory in the management of glaucoma. Data on glaucoma progression from older as well as most recent literature findings are summarized in this article. In addition, the article elaborates on the scientific content from a series of lectures given by experts in the field during several international symposia on 'rate of progression' in 2008. This review summarizes key findings on the natural history of glaucoma and known factors for disease progression. It highlights the visual function changes observed as glaucoma progresses and discusses disease impact on patients' quality of life. Findings support the need to obtain information on rate of progression and its importance for clinical management. Practical ways to measure rate of progression are given by new software options to help measure major parameters. Finally, on the basis of a patient's individual rate of progression therapeutic options are assessed, such as maximum medical therapy with fixed combinations. Estimating a patient's individual rate of VF progression by using newly developed analyses will be helpful to forecast the potential future development of the glaucoma. An individualized treatment approach then requires that in patients in whom the risk of becoming visually impaired or blind during their lifetime is higher, a more intensive medical IOP-lowering therapy such as fixed combinations can be considered as treatment option.

  3. Relative importance of strength, power, and anthropometric measures to jump performance of elite volleyball players.

    Science.gov (United States)

    Sheppard, Jeremy M; Cronin, John B; Gabbett, Tim J; McGuigan, Michael R; Etxebarria, Naroa; Newton, Robert U

    2008-05-01

    The purpose of this investigation was to examine the potential strength, power, and anthropometric contributors to vertical jump performances that are considered specific to volleyball success: the spike jump (SPJ) and counter-movement vertical jump (CMVJ). To assess the relationship among strength, power, and anthropometric variables with CMVJ and SPJ, a correlation and regression analysis was performed. In addition, a comparison of strength, power, and anthropometric differences between the seven best subjects and the seven worst athletes on the CMVJ test and SPJ test was performed. When expressed as body mass relative measures, moderate correlations (0.53-0.65; p performance and relative SPJ (0.85; p performance, explaining 84% of performance. The single best predictor for relative SPJ was also the relative depth jump performance (72% of performance), with the three-component models of relative depth jump, relative CMVJ, spike jump contribution (percent difference between SPJ and CMVJ), and relative CMVJ, spike jump contribution, and peak force, accounting for 96% and 97%, respectively. The results of this study clearly demonstrate that in an elite population of volleyball players, stretch-shortening cycle performance and the ability to tolerate high stretch loads, as in the depth jump, is critical to performance in the jumps associated with volleyball performance.

  4. The importance of measuring self-efficacy in patients with diabetes.

    Science.gov (United States)

    Mishali, M; Omer, H; Heymann, A D

    2011-02-01

    Self-efficacy is an important factor influencing diabetes self-management behaviours. Previous studies have examined self-efficacy as a general measure in diabetes care for all self-care treatment recommendations together. This current study was designed to examine if low self-efficacy in each of the measured self-care treatment recommendations is related to decreased adherence for each specific recommendation. The self-efficacy was measured in 119 patients for four different treatment recommendations: blood glucose self-monitoring, exercise, diet and oral medication intake and correlated with The Resistance to Treatment Questionnaire. Significant and positive Pearson's correlations were found between the frequency of adherence to treatment recommendations and the self-efficacy regarding different recommendations. The correlation between self-efficacy and diet and physical activity was 0.5 and 0.67, respectively. The higher the resistance to treatment score, the less confident the patient is in his or her ability to adhere with treatment recommendations. This pattern was not present in adherence to medication intake. Self-efficacy impacts adherence to treatment and therefore plays a role in the clinical outcome. The practical implication is that assessment of self-efficacy in people with diabetes may be a first step in the development of individually tailored interventions.

  5. The more things change, the more they stay the same? When is trait variability important for stability of ecosystem function in a changing environment.

    Science.gov (United States)

    Wright, Justin P; Ames, Gregory M; Mitchell, Rachel M

    2016-05-19

    The importance of intraspecific trait variability for community dynamics and ecosystem functioning has been underappreciated. There are theoretical reasons for predicting that species that differ in intraspecific trait variability will also differ in their effects on ecosystem functioning, particularly in variable environments. We discuss whether species with greater trait variability are likely to exhibit greater temporal stability in their population dynamics, and under which conditions this might lead to stability in ecosystem functioning. Resolving this requires us to consider several questions. First, are species with high levels of variation for one trait equally variable in others? In particular, is variability in response and effects traits typically correlated? Second, what is the relative contribution of local adaptation and phenotypic plasticity to trait variability? If local adaptation dominates, then stability in function requires one of two conditions: (i) individuals of appropriate phenotypes present in the environment at high enough frequencies to allow for populations to respond rapidly to the changing environment, and (ii) high levels of dispersal and gene flow. While we currently lack sufficient information on the causes and distribution of variability in functional traits, filling in these key data gaps should increase our ability to predict how changing biodiversity will alter ecosystem functioning. © 2016 The Author(s).

  6. Measurement of strength and loading variables on the knee during Alpine skiing.

    Science.gov (United States)

    Maxwell, S M; Hull, M L

    1989-01-01

    The study focusses on the prevention of knee injuries during snow skiing. In order to develop a technology of knee injury prevention, both the strength and loading on the knee during skiing activity must be known. This paper reports measurements of variables influencing both knee strength and loading of the joint. The strength variables measured included the degree of activity in six muscles crossing the knee, the knee flexion angle, and the axial load (i.e. weight bearing) transmitted to the knee. Transducers included surface electrodes to monitor electromyogram signals indicating the degree of muscle activity and a goniometer to measure both hip and knee flexion angles. The complete loading on the knee was derived from a dynamometer which measured the six load components at the boot-dynamometer interface. The transducer data were acquired and stored by a compact, battery powered digital data acquisition-controller system. Three male subjects of similar physical size (nominal was 1.8 m and 75 kg) and skiing ability (advanced intermediate to expert) were tested under similar conditions. Each subject skied a total of four slalom runs--one snowplow and three parallel. The total time of each test was 21 s. Example data plots from different types of runs are presented and discussed. Based on observations from the data, necessary performance features for ski bindings offering improved protection from knee ligamentous injuries are defined.

  7. Correlations between Sportsmen’s Morpho-Functional Measurements and Voice Acoustic Variables

    Directory of Open Access Journals (Sweden)

    Rexhepi Agron M.

    2016-12-01

    Full Text Available Purpose. Since human voice characteristics are specific to each individual, numerous anthropological studies have been oriented to find significant relationships between voice and morpho-functional features. The goal of this study was to identify the correlation between seven morpho-functional variables and six voice acoustic parameters in sportsmen. Methods. Following the protocols of the International Biological Program, seven morpho-functional variables and six voice acoustic parameters have been measured in 88 male professional athletes from Kosovo, aged 17-35 years, during the period of April-October 2013. The statistical analysis was accomplished through the SPSS program, version 20. The obtained data were analysed through descriptive parameters and with Spearman’s method of correlation analysis. Results. Spearman’s method of correlation showed significant negative correlations (R = -0.215 to -0.613; p = 0.05 between three voice acoustic variables of the fundamental frequency of the voice sample (Mean, Minimum, and Maximum Pitch and six morpho-functional measures (Body Height, Body Weight, Margaria-Kalamen Power Test, Sargent Jump Test, Pull-up Test, and VO2max.abs. Conclusions. The significant correlations imply that the people with higher stature have longer vocal cords and a lower voice. These results encourage investigations on predicting sportsmen’s functional abilities on the basis of their voice acoustic parameters.

  8. A protocol for measuring spatial variables in soft-sediment tide pools

    Directory of Open Access Journals (Sweden)

    Marina R. Brenha-Nunes

    2016-01-01

    Full Text Available ABSTRACT We present a protocol for measuring spatial variables in large (>50 m2 soft-sediment tide pool. Secondarily, we present the fish capture efficiency of a sampling protocol that based on such spatial variables to calculate relative abundances. The area of the pool is estimated by summing areas of basic geometric forms; the depth, by taken representative measurements of the depth variability of each pool's sector, previously determined according to its perimeter; and the volume, by considering the pool as a prism. These procedures were a trade-off between the acquisition of reliable estimates and the minimization of both the cost of operating and the time spent in field. The fish sampling protocol is based on two con secutive stages: 1 two people search for fishes under structures (e.g., rocks and litters on the pool and capture them with hand seines; 2 these structures are removed and then a beach-seine is hauled over the whole pool. Our method is cheaper than others and fast to operate considering the time in low tides. The method to sample fish is quite efficient resulting in a capture efficiency of 89%.

  9. Variability in heart rate recovery measurements over 1 year in healthy, middle-aged adults.

    Science.gov (United States)

    Mellis, M G; Ingle, L; Carroll, S

    2014-02-01

    This study assessed the longer-term (12-month) variability in post-exercise heart rate recovery following a submaximal exercise test. Longitudinal data was analysed for 97 healthy middle-aged adults (74 male, 23 female) from 2 occasions, 12 months apart. Participants were retrospectively selected if they had stable physical activity habits, submaximal treadmill fitness and anthropometric measurements between the 2 assessment visits. A submaximal Bruce treadmill test was performed to at least 85% age-predicted maximum heart rate. Absolute heart rate and Δ heart rate recovery (change from peak exercise heart rate) were recorded for 1 and 2 min post-exercise in an immediate supine position. Heart rate recovery at both time-points was shown to be reliable with intra-class correlation coefficient values ≥ 0.714. Absolute heart rate 1-min post-exercise showed the strongest agreement between repeat tests (r = 0.867, P heart rate values rather than Δ heart rate recovery, and for 1-min rather than 2-min post-exercise recovery time points. Log-transformed values generated better variability with acceptable coefficient of variation for all measures (2.2-10%). Overall, 1 min post-exercise heart rate recovery data had least variability over the 12-month period in apparently healthy middle-aged adults. © Georg Thieme Verlag KG Stuttgart · New York.

  10. Measuring perceptions related to e-cigarettes: Important principles and next steps to enhance study validity.

    Science.gov (United States)

    Gibson, Laura A; Creamer, MeLisa R; Breland, Alison B; Giachello, Aida Luz; Kaufman, Annette; Kong, Grace; Pechacek, Terry F; Pepper, Jessica K; Soule, Eric K; Halpern-Felsher, Bonnie

    2018-04-01

    Measuring perceptions associated with e-cigarette use can provide valuable information to help explain why youth and adults initiate and continue to use e-cigarettes. However, given the complexity of e-cigarette devices and their continuing evolution, measures of perceptions of this product have varied greatly. Our goal, as members of the working group on e-cigarette measurement within the Tobacco Centers of Regulatory Science (TCORS) network, is to provide guidance to researchers developing surveys concerning e-cigarette perceptions. We surveyed the 14 TCORS sites and received and reviewed 371 e-cigarette perception items from seven sites. We categorized the items based on types of perceptions asked, and identified measurement approaches that could enhance data validity and approaches that researchers may consider avoiding. The committee provides suggestions in four areas: (1) perceptions of benefits, (2) harm perceptions, (3) addiction perceptions, and (4) perceptions of social norms. Across these 4 areas, the most appropriate way to assess e-cigarette perceptions depends largely on study aims. The type and number of items used to examine e-cigarette perceptions will also vary depending on respondents' e-cigarette experience (i.e., user vs. non-user), level of experience (e.g., experimental vs. established), type of e-cigarette device (e.g., cig-a-like, mod), and age. Continuous formative work is critical to adequately capture perceptions in response to the rapidly changing e-cigarette landscape. Most important, it is imperative to consider the unique perceptual aspects of e-cigarettes, building on the conventional cigarette literature as appropriate, but not relying on existing conventional cigarette perception items without adjustment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. The importance of deep, basinwide measurements in optimized Atlantic Meridional Overturning Circulation observing arrays

    Science.gov (United States)

    McCarthy, G. D.; Menary, M. B.; Mecking, J. V.; Moat, B. I.; Johns, W. E.; Andrews, M. B.; Rayner, D.; Smeed, D. A.

    2017-03-01

    The Atlantic Meridional Overturning Circulation (AMOC) is a key process in the global redistribution of heat. The AMOC is defined as the maximum of the overturning stream function, which typically occurs near 30°N in the North Atlantic. The RAPID mooring array has provided full-depth, basinwide, continuous estimates of this quantity since 2004. Motivated by both the need to deliver near real-time data and optimization of the array to reduce costs, we consider alternative configurations of the mooring array. Results suggest that the variability observed since 2004 could be reproduced by a single tall mooring on the western boundary and a mooring to 1500 m on the eastern boundary. We consider the potential future evolution of the AMOC in two generations of the Hadley Centre climate models and a suite of additional CMIP5 models. The modeling studies show that deep, basinwide measurements are essential to capture correctly the future decline of the AMOC. We conclude that, while a reduced array could be useful for estimates of the AMOC on subseasonal to decadal time scales as part of a near real-time data delivery system, extreme caution must be applied to avoid the potential misinterpretation or absence of a climate time scale AMOC decline that is a key motivation for the maintenance of these observations.Plain Language SummaryThe Atlantic Overturning Circulation is a system of ocean currents that carries heat northwards in the Atlantic. This heat is crucial to maintaining the mild climate of northwest Europe. The Overturning Circulation is predicted to slow in future in response to man-made climate change. The RAPID program is designed to measure the Overturning Circulation using a number of fixed point observations spanning the Atlantic between the Canary Islands and the Bahamas. We look at whether we could reduce the number of these fixed point observations to continue to get accurate estimates of the overturning strength but for less cost. We conclude that

  12. The importance of sensory-motor control in providing core stability: implications for measurement and training.

    Science.gov (United States)

    Borghuis, Jan; Hof, At L; Lemmink, Koen A P M

    2008-01-01

    correlation was found between poor balance performance in a sitting balance task and delayed firing of the trunk muscles during sudden perturbation. It was suggested that both phenomena are caused by proprioceptive deficits. The importance of sensory-motor control has implications for the development of measurement and training protocols. It has been shown that challenging propriocepsis during training activities, for example, by making use of unstable surfaces, leads to increased demands on trunk muscles, thereby improving core stability and balance. Various tests to directly or indirectly measure neuromuscular control and coordination have been developed and are discussed in the present article. Sitting balance performance and trunk muscle response times may be good indicators of core stability. In light of this, it would be interesting to quantify core stability using a sitting balance task, for example by making use of accelerometry. Further research is required to develop training programmes and evaluation methods that are suitable for various target groups.

  13. Variability in sublingual microvessel density and flow measurements in healthy volunteers.

    Science.gov (United States)

    Hubble, Sheena M A; Kyte, Hayley L; Gooding, Kim; Shore, Angela C

    2009-02-01

    As sublingual microvascular indices are increasingly heralded as new resuscitation end-points, better population data are required to power clinical studies. This paper describes improved methods to quantify sublingual microvessel flow and density in images obtained by sidestream dark field (SDF) technology in healthy volunteers, including vessels under 10 microm in diameter. Measurements of sublingual capillary density and flow were obtained by recording three 15-second images in 20 healthy volunteers over three days. Two independent observers quantified capillary density by using two methods: total vessel length (mm/mm2) and counting (number/mm). Both intraoral and temporal variabilities within subject and observer reproducibilities were determined by using coefficients of variability and reproducibility indices. For small (1-10 microm), medium (11-20 microm), and large (21-50 microm) diameter, mean vessel density with standard deviations (SDs) in volunteers was 21.3(+/- 4.9), 5.2 (+/- 1.2), and 2.7 (+/- 0.9) mm/mm2, respectively. Also, 94.0 +/- 1.4% of small vessels, 94.5 +/- 1.4% of medium vessels, and 94.5+/- 4.0% of large vessels had continuous perfusion. Within subjects, the means of all measurements over three days varied less than 13, 22, and 35% in small, medium, and large vessels, respectively. Interobserver reproducibility was good, especially for capillary (1-10 microm) density and flow measurements. Our methods of microvessel flow and density quantification have low observer variability and confirm the stability of microcirculatory measurements over time. These results facilitate the development of SDF-acquired sublingual microvascular indices as feasible microperfusion markers in shock resuscitation.

  14. [The Study of the Measurement of Heart Rate Variability Using ECG and Photoplethysmographic Signal].

    Science.gov (United States)

    Wang, Buqing; Chai, Xiaoke; Zhang Zhengbo; Wang, Weidong

    2015-07-01

    In comparison with the measurement of heart rate variability from ECG and from photoplethysmographic signal from 46 healthy adults in their spontaneous breathing state. The beat-to-beat intervals in ECG and pulse-to-pulse intervals in photoplethysmographic signal are extracted, and then the parameters of heart rate variability are calculated. Three kinds of algorithms are chosen to get the pulse-to-pulse intervals, which are the intervals of maximum of second derivative, the maximum of PPG signal and the tangent intersection. The results show that the correlation coefficients of the HRV parameters in the two calculation methods are highly correlated. The Bland-Altman scattered plots show the relative bias results from the algorithm of the maximum of PPG signal are smallest and singular points that deviate from the consistent limits are the least compared with the other two algorithms.

  15. Reconstruction of global atmospheric dust concentrations using dust flux measurements in paleoclimatic archives and dust model variables

    Science.gov (United States)

    Lambert, F.; Rojas, M.; Gallardo, L.; Mahowald, N. M.; Takemura, T.; KUG, J.; Winckler, G.; Park, R.; Abe-Ouchi, A.

    2013-12-01

    Aerosols are the second most potent agent affecting anthropogenic radiative forcing after greenhouse gases. However, despite some progress in the field, the uncertainty of aerosol impact on present and past climate remains much larger than for other species. The total atmospheric dust load is an important factor for the radiative budget of the atmosphere, and for the micronutrient supply to terrestrial and marine ecosystems. We have collected published dust flux (mass accumulation rate) measurements from marine sediment cores, ice cores, loess fields, and peat bogs. These measurements are interpolated to two global grids of average Holocene and Last Glacial Maximum (LGM) climatic conditions. The interpolation is performed using a kriging algorithm and its uncertainty shows regions where new measurements are most needed. We have developed a new method that combines observational dust flux measurements with dust depositional variables from climate models to reconstruct average Holocene and LGM atmospheric dust concentrations. Here we use dust simulations from two different coupled GCMs (CAM3-CCSM3 and SPRINTARS-MIROC) to give an idea of the uncertainties due to model variables. Our reconstructions give a different perspective on Holocene and LGM atmospheric dust loads from pure model simulations. The discrepancies between modeled and reconstructed dust concentrations and radiative forcing gives insights on regions and variables that may be improved in the models. In addition, this method allows to follow the temporal and spatial evolution of dust loads (and the resulting changes in radiative forcing and iron fertilization) through the glacial-interglacial transition. Top row: Interpolated Mass Accumulation Rates (MAR) for average Holocene (left column) and Last Glacial Maximum (right column) climatic conditions. The second and third row show simulated MAR from two different coupled climate models.

  16. Variables Associated with the Use of Coercive Measures on Psychiatric Patients in Spanish Penitentiary Centers

    Directory of Open Access Journals (Sweden)

    E. Girela

    2014-01-01

    Full Text Available We have studied the use of coercive medical measures (forced medication, isolation, and mechanical restraint in mentally ill inmates within two secure psychiatric hospitals (SPH and three regular prisons (RP in Spain. Variables related to adopted coercive measures were analyzed, such as type of measure, causes of indication, opinion of patient inmate, opinion of medical staff, and more frequent morbidity. A total of 209 patients (108 from SPH and 101 from RP were studied. Isolation (41.35% was the most frequent coercive measure, followed by mechanical restraint (33.17% and forced medication (25.48%. The type of center has some influence; specifically in RP there is less risk of isolation and restraint than in SPH. Not having had any previous imprisonment reduces isolation and restraint risk while increases the risk of forced medication, as well as previous admissions to psychiatric inpatient units does. Finally, the fact of having lived with a partner before imprisonment reduces the risk of forced medication and communication with the family decreases the risk of isolation. Patients subjected to a coercive measure exhibited a pronounced psychopathology and most of them had been subjected to such measures on previous occasions. The mere fact of external assessment of compliance with human rights slows down the incidence of coercive measures.

  17. Importance of Viral Sequence Length and Number of Variable and Informative Sites in Analysis of HIV Clustering.

    Science.gov (United States)

    Novitsky, Vlad; Moyo, Sikhulile; Lei, Quanhong; DeGruttola, Victor; Essex, M

    2015-05-01

    To improve the methodology of HIV cluster analysis, we addressed how analysis of HIV clustering is associated with parameters that can affect the outcome of viral clustering. The extent of HIV clustering and tree certainty was compared between 401 HIV-1C near full-length genome sequences and subgenomic regions retrieved from the LANL HIV Database. Sliding window analysis was based on 99 windows of 1,000 bp and 45 windows of 2,000 bp. Potential associations between the extent of HIV clustering and sequence length and the number of variable and informative sites were evaluated. The near full-length genome HIV sequences showed the highest extent of HIV clustering and the highest tree certainty. At the bootstrap threshold of 0.80 in maximum likelihood (ML) analysis, 58.9% of near full-length HIV-1C sequences but only 15.5% of partial pol sequences (ViroSeq) were found in clusters. Among HIV-1 structural genes, pol showed the highest extent of clustering (38.9% at a bootstrap threshold of 0.80), although it was significantly lower than in the near full-length genome sequences. The extent of HIV clustering was significantly higher for sliding windows of 2,000 bp than 1,000 bp. We found a strong association between the sequence length and proportion of HIV sequences in clusters, and a moderate association between the number of variable and informative sites and the proportion of HIV sequences in clusters. In HIV cluster analysis, the extent of detectable HIV clustering is directly associated with the length of viral sequences used, as well as the number of variable and informative sites. Near full-length genome sequences could provide the most informative HIV cluster analysis. Selected subgenomic regions with a high extent of HIV clustering and high tree certainty could also be considered as a second choice.

  18. [The importance of relationship satisfaction and the questionnaire techniques of its measurement].

    Science.gov (United States)

    Vajda, Dóra; Sz Makó, Hajnalka

    2014-01-01

    The quality of marriage or partnership has an impact on many areas of life. Consequently, a good working relationship can be a significant resource to cope with difficult life situations and stress, and may contribute to partners' well-being and healthy lifestyle. Therefore, its investigation has particular relevance. Relationship satisfaction is a complex concept which is confirmed by both diversity and multidimensionality of its definition. The aim of this study is to provide an overview of the importance of relationship satisfaction, inter- and intrapersonal factors influencing its development, its changes over family life cycles and the gender differences that may manifest in relationship satisfaction. In addition, this review summarizes the questionnaire techniques of measuring relationship satisfaction which are also reflected within the complexity and the diversity of the concept. Given the fact that the degree of relationship satisfaction plays a salient role in many aspects of life, the empirical research findings which emphasize the importance of this conception can serve as an alternative to aim the mobilization of its practical work.

  19. Importance of measuring discharge and sediment transport in lesser tributaries when closing sediment budgets

    Science.gov (United States)

    Griffiths, Ronald E.; Topping, David J.

    2017-11-01

    Sediment budgets are an important tool for understanding how riverine ecosystems respond to perturbations. Changes in the quantity and grain size distribution of sediment within river systems affect the channel morphology and related habitat resources. It is therefore important for resource managers to know if a river reach is in a state of sediment accumulation, deficit or stasis. Many sediment-budget studies have estimated the sediment loads of ungaged tributaries using regional sediment-yield equations or other similar techniques. While these approaches may be valid in regions where rainfall and geology are uniform over large areas, use of sediment-yield equations may lead to poor estimations of loads in regions where rainfall events, contributing geology, and vegetation have large spatial and/or temporal variability. Previous estimates of the combined mean-annual sediment load of all ungaged tributaries to the Colorado River downstream from Glen Canyon Dam vary by over a factor of three; this range in estimated sediment loads has resulted in different researchers reaching opposite conclusions on the sign (accumulation or deficit) of the sediment budget for particular reaches of the Colorado River. To better evaluate the supply of fine sediment (sand, silt, and clay) from these tributaries to the Colorado River, eight gages were established on previously ungaged tributaries in Glen, Marble, and Grand canyons. Results from this sediment-monitoring network show that previous estimates of the annual sediment loads of these tributaries were too high and that the sediment budget for the Colorado River below Glen Canyon Dam is more negative than previously calculated by most researchers. As a result of locally intense rainfall events with footprints smaller than the receiving basin, floods from a single tributary in semi-arid regions can have large (≥ 10 ×) differences in sediment concentrations between equal magnitude flows. Because sediment loads do not

  20. Vertical Variability of Rain Drop Size Distribution from Micro Rain Radar Measurements during IFloodS

    Science.gov (United States)

    Adirosi, Elisa; Tokay, Ali; Roberto, Nicoletta; Gorgucci, Eugenio; Montopoli, Mario; Baldini, Luca

    2017-04-01

    Ground based weather radars are highly used to generate rainfall products for meteorological and hydrological applications. However, weather radar quantitative rainfall estimation is obtained at a certain altitude that depends mainly on the radar elevation angle and on the distance from the radar. Therefore, depending on the vertical variability of rainfall, a time-height ambiguity between radar measurement and rainfall at the ground can affect the rainfall products. The vertically pointing radars (such as the Micro Rain Radar, MRR) are great tool to investigate the vertical variability of rainfall and its characteristics and ultimately, to fill the gap between the ground level and the first available radar elevation. Furthermore, the knowledge of rain Drop Size Distribution (DSD) variability is linked to the well-known problem of the non-uniform beam filling that is one of the main uncertainties of Global Precipitation Measurement (GPM) mission Dual frequency Precipitation Radar (DPR). During GPM Ground Validation Iowa Flood Studies (IFloodS) field experiment, data collected with 2D video disdrometers (2DVD), Autonomous OTT Parsivel2 Units (APU), and MRR profilers at different sites were available. In three different sites co-located APU, 2DVD and MRR are available and covered by the S-band Dual Polarimetric Doppler radar (NPOL). The first elevation height of the radar beam varies, among the three sites, between 70 m and 1100 m. The IFloodS set-up has been used to compare disdrometers, MRR and NPOL data and to evaluate the uncertainties of those measurements. First, the performance of disdrometers and MRR in determining different rainfall parameters at ground has been evaluated and then the MRR based parameters have been compared with the ones obtained from NPOL data at the lowest elevations. Furthermore, the vertical variability of DSD and integral rainfall parameters within the MRR bins (from ground to 1085 m each 35 m) has been investigated in order to provide

  1. Control measures following a case of imported Lassa fever from Togo, North Rhine Westphalia, Germany, 2016.

    Science.gov (United States)

    Lehmann, Clara; Kochanek, Matthias; Abdulla, Diana; Becker, Stephan; Böll, Boris; Bunte, Anne; Cadar, Daniel; Dormann, Arno; Eickmann, Markus; Emmerich, Petra; Feldt, Torsten; Frank, Christina; Fries, Jochen; Gabriel, Martin; Goetsch, Udo; Gottschalk, René; Günther, Stephan; Hallek, Michael; Häussinger, Dieter; Herzog, Christian; Jensen, Björn; Kolibay, Felix; Krakau, Michael; Langebartels, Georg; Rieger, Toni; Schaade, Lars; Schmidt-Chanasit, Jonas; Schömig, Edgar; Schüttfort, Gundolf; Shimabukuro-Vornhagen, Alexander; von Bergwelt-Baildon, Michael; Wieland, Ulrike; Wiesmüller, Gerhard; Wolf, Timo; Fätkenheuer, Gerd

    2017-09-01

    In a patient transferred from Togo to Cologne, Germany, Lassa fever was diagnosed 12 days post mortem. Sixty-two contacts in Cologne were categorised according to the level of exposure, and gradual infection control measures were applied. No clinical signs of Lassa virus infection or Lassa specific antibodies were observed in the 62 contacts. Thirty-three individuals had direct contact to blood, other body fluids or tissue of the patients. Notably, with standard precautions, no transmission occurred between the index patient and healthcare workers. However, one secondary infection occurred in an undertaker exposed to the corpse in Rhineland-Palatinate, who was treated on the isolation unit at the University Hospital of Frankfurt. After German authorities raised an alert regarding the imported Lassa fever case, an American healthcare worker who had cared for the index patient in Togo, and who presented with diarrhoea, vomiting and fever, was placed in isolation and medevacked to the United States. The event and the transmission of Lassa virus infection outside of Africa underlines the need for early diagnosis and use of adequate personal protection equipment (PPE), when highly contagious infections cannot be excluded. It also demonstrates that larger outbreaks can be prevented by infection control measures, including standard PPE.

  2. IMPORTANCE OF MEASURING LEVELS OF INFLIXIMAB IN PATIENTS TREATING INFLAMMATORY BOWEL DISEASE IN A BRAZILIAN COHORT

    Directory of Open Access Journals (Sweden)

    Katia Cristina KAMPA

    2017-09-01

    Full Text Available ABSTRACT BACKGROUND: Crohn’s disease and ulcerative colitis are chronic inflammatory bowel diseases. In such pathologies, there is an increased production of alpha tumor necrosis factor (TNF-α. Patients, in whom the conventional immunosuppressant treatment fails, require the use of immunobiological therapy, such as anti-TNF-α, a monoclonal antibody. Infliximab is an anti-TNF-α drug, a chimerical immunoglobulin, with a murine component, which is responsible for the generation of immunogenicity against the drug and formation of anti-TNF-α antibodies. The presence of anti-drug antibodies may be responsible for adverse events and reduction of the drug’s effectiveness. Patients with inflammatory bowel diseases undergoing therapy with biological medication, such as infliximab, can relapse overtime and this may not be translated into clinical symptoms. Thus, there is a need for a method to evaluate the efficacy of the drug, through the measurement of serum infliximab levels, as well as antibodies research. OBJECTIVE: This study aimed to measure serum infliximab levels and anti-infliximab antibodies in patients with inflammatory bowel diseases post-induction phase and during maintenance therapy, and describe the therapeutic modifications that took place based on the serum levels results. METHODS: It was a retrospective study, that included forty-five patients, with a total of 63 samples of infliximab measurement. RESULTS: Twenty-one patients had an adequate infliximab serum level, 31 had subtherapeutic levels and 11 had supratherapeutic levels. Seven patients had their medication suspended due to therapeutic failure or high levels of antibodies to infliximab. CONCLUSION: In conclusion, only a third of the patients had adequate infliximab levels and 36% presented with subtherapeutic levels at the end of the induction phase. Therapy optimization occurred based in about 46% of the samples results, demonstrating the importance of having this tool to

  3. A Method to Measure the Unbiased Decorrelation Timescale of the AGN Variable Signal from Structure Functions

    Science.gov (United States)

    Kozłowski, Szymon

    2017-02-01

    A simple, model-independent method to quantify the stochastic variability of active galactic nuclei (AGNs) is the structure function (SF) analysis. If the SF for the timescales shorter than the decorrelation timescale τ is a single power law and for the longer ones becomes flat (I.e., white noise), then the auto-correlation function (ACF) of the signal can have the form of the power exponential (PE). We show that the signal decorrelation timescale can be measured directly from the SF as the timescale matching the amplitude 0.795 of the flat SF part (at long timescales), and only then is the measurement independent of the ACF PE power. Typically, the timescale has been measured at an arbitrarily fixed SF amplitude, but as we prove, this approach provides biased results, because the AGN SF/power spectral density slopes, and thus the ACF shape, are not constant and depend on either the AGN luminosity and/or the black hole mass. In particular, we show that using such a method for the simulated SFs that includes a combination of empirically known dependencies between the AGN luminosity L and both the SF amplitude and the PE power, and having no intrinsic τ-L dependence, produces a fake τ \\propto {L}κ relation with 0.3≲ κ ≲ 0.6, which otherwise is expected from theoretical works (κ \\equiv 0.5). Our method provides an alternative means for analyzing AGN variability to the standard SF fitting. The caveats, for both methods, are that the light curves must be sufficiently long (with a several year rest frame) and the ensemble SF assumes AGNs to have the same underlying variability process.

  4. Political Participation: A Latent Variable Approach. Testing Measurement Equivalence of Political Participation Using ESS Data

    Directory of Open Access Journals (Sweden)

    Marina Goroshit

    2016-01-01

    Full Text Available Theoretical definitions refer to political participation as multi-faceted. While some authors introduce up to twenty different kinds of behavior to measure political action, political participation is measured in surveys like ESS, WVS or EVS by a limited number of activities. Most of the researchers of political participation use composite scores for measuring political participation. The main aim of this research was to test (i “whether political participation can be measured as a latent construct?” and (ii “is this construct measurement equivalent across different countries or different time points?” Using the 5th round of ESS data and the alignment procedure, I measured cross-country comparability of political participation as a bi-dimensional construct with 2 latent factors: institutional and non-institutional participation. Results showed that for the vast majority of ESS countries, the data reflect the theoretical construct of political participation. Furthermore, I compared between the time points within each country and I found that, with few exceptions, the ESS countries show temporal invariance regarding the political participation construct. Both results suggest that political participation can be treated as latent variable and allow us further cross-cultural comparisons.

  5. Context matters! sources of variability in weekend physical activity among families: a repeated measures study

    Directory of Open Access Journals (Sweden)

    Robert J. Noonan

    2017-04-01

    Full Text Available Abstract Background Family involvement is an essential component of effective physical activity (PA interventions in children. However, little is known about the PA levels and characteristics of PA among families. This study used a repeated measures design and multiple data sources to explore the variability and characteristics of weekend PA among families. Methods Families (including a ‘target’ child aged 9–11 years, their primary caregiver(s and siblings aged 6–8 years were recruited through primary schools in Liverpool, UK. Participants completed a paper-based PA diary and wore an ActiGraph GT9X accelerometer on their left wrist for up to 16 weekend days. ActiGraph.csv files were analysed using the R-package GGIR version 1.1–4. Mean minutes of moderate-to-vigorous PA (MVPA for each weekend of measurement were calculated using linear mixed models, and variance components were estimated for participant (inter-individual, weekend of measurement, and residual error (intra-individual. Intraclass correlation coefficients (ICC were calculated from the proportion of total variance accounted for by inter-individual sources, and used as a measure of reliability. Diary responses were summed to produce frequency counts. To offer contextual insight into weekend PA among family units, demographic, accelerometer, and diary data were combined to form two case studies representative of low and high active families. Results Twenty-five participants from 7 families participated, including 7 ‘target’ children (mean age 9.3 ± 1.1 years, 4 boys, 6 siblings (mean age 7.2 ± 0.7 years; 4 boys and 12 adults (7 mothers and 5 fathers. There was a high degree of variability in target children’s (ICC = 0.55, siblings (ICC = 0.38, and mothers’ MVPA (ICC = 0.58, but not in fathers’ MVPA (ICC = 0.83. Children’s weekend PA was mostly unstructured in nature and undertaken with friends, whereas a greater proportion of parents’ weekend

  6. Robust shot-noise measurement for continuous-variable quantum key distribution

    Science.gov (United States)

    Kunz-Jacques, Sébastien; Jouguet, Paul

    2015-02-01

    We study a practical method to measure the shot noise in real time in continuous-variable quantum key distribution systems. The amount of secret key that can be extracted from the raw statistics depends strongly on this quantity since it affects in particular the computation of the excess noise (i.e., noise in excess of the shot noise) added by an eavesdropper on the quantum channel. Some powerful quantum hacking attacks relying on faking the estimated value of the shot noise to hide an intercept and resend strategy were proposed. Here, we provide experimental evidence that our method can defeat the saturation attack and the wavelength attack.

  7. Modelling global water stress of the recent past: on the relative importance of trends in water demand and climate variability

    Science.gov (United States)

    Wada, Y.; van Beek, L. P. H.; Bierkens, M. F. P.

    2011-12-01

    During the past decades, human water use has more than doubled, yet available freshwater resources are finite. As a result, water scarcity has been prevalent in various regions of the world. Here, we present the first global assessment of past development of water stress considering not only climate variability but also growing water demand, desalinated water use and non-renewable groundwater abstraction over the period 1960-2001 at a spatial resolution of 0.5°. Agricultural water demand is estimated based on past extents of irrigated areas and livestock densities. We approximate past economic development based on GDP, energy and household consumption and electricity production, which are subsequently used together with population numbers to estimate industrial and domestic water demand. Climate variability is expressed by simulated blue water availability defined by freshwater in rivers, lakes, wetlands and reservoirs by means of the global hydrological model PCR-GLOBWB. We thus define blue water stress by comparing blue water availability with corresponding net total blue water demand by means of the commonly used, Water Scarcity Index. The results show a drastic increase in the global population living under water-stressed conditions (i.e. moderate to high water stress) due to growing water demand, primarily for irrigation, which has more than doubled from 1708/818 to 3708/1832 km3 yr-1 (gross/net) over the period 1960-2000. We estimate that 800 million people or 27% of the global population were living under water-stressed conditions for 1960. This number is eventually increased to 2.6 billion or 43% for 2000. Our results indicate that increased water demand is a decisive factor for heightened water stress in various regions such as India and North China, enhancing the intensity of water stress up to 200%, while climate variability is often a main determinant of extreme events. However, our results also suggest that in several emerging and developing economies

  8. Transverse Acoustic Measurements of Superuid Helium-3 at Fixed and Variable Path Lengths

    Science.gov (United States)

    Collett, Charles Alward

    This thesis describes experiments using transverse zero sound in pure superfluid 3He to probe excitations with energies below the superfluid gap. One main focus is on a collective mode of the order parameter, the imaginary squashing mode. The splitting of this mode in a magnetic field causes acoustic birefringence, which rotates the polarization axis of the transverse sound wave. We have made precise measurements of this rotation in magnetic fields up to 0.11 T and observed the onset of nonlinear field dependence. Our measurements of the linear field dependence disagree with theoretical predictions, which led us to discover that the theory only applies when the sound frequency is close to the mode frequency, a condition not satisfied in our experiments. We extrapolated our data to the region of validity of the theory, and measured attractive sub-dominant f-wave pairing interactions. The other main focus is the construction of an experimental apparatus to enable in situ variation of the acoustic cavity spacing at low temperatures. Recent measurements have indicated a coupling between the transverse sound attenuation and surface Andreev bound states, which are predicted to be Majorana states in the specular scattering limit. A variable path length sample cell would enable measurements of the absolute attenuation of transverse sound, as well as allow for the separation of bulk effects from surface effects. It would also enable experiments looking for transverse zero sound in the normal state of 3He, which is predicted to have a high attenuation length requiring a micron-scale acoustic cavity. We have designed and implemented a diaphragm-based variable path length cell, and discuss our current progress and future prospects.

  9. Variability of GPS units for measuring distance in team sport movements.

    Science.gov (United States)

    Jennings, Denise; Cormack, Stuart; Coutts, Aaron J; Boyd, Luke J; Aughey, Robert J

    2010-12-01

    To examine the difference in distance measured by two global positioning system (GPS) units of the same model worn by the same player while performing movements common to team sports. Twenty elite Australian football players completed two trials of the straight line movement (10, 20, 40 m) at four speeds (walk, jog, stride, sprint), two trials of the changes of direction (COD) courses of two different frequencies (gradual and tight), and five trials of a team sport running simulation circuit. To assess inter-unit variability for total and high intensity running (HIR) distance measured in matches, data from eight field players were collected in three Australian Hockey League (AHL) matches during the 2009 season. Each subject wore two GPS devices (MinimaxX v2.5, Catapult, Australia) that collected position data at 5 Hz for each movement and match trial. The percentage difference ±90% confidence interval (CI) was used to determine differences between units. Differences (±90% CI) between the units ranged from 9.9 ± 4.7% to 11.9 ± 19.5% for straight line running movements and from 9.5 ± 7.2% to 10.7 ± 7.9% in the COD courses. Similar results were exhibited in the team sport circuit (11.1 ± 4.2%). Total distance (10.3 ± 6.2%) and HIR distance (10.3 ± 15.6) measured during the match play displayed similar variability. It is recommended that players wear the same GPS unit for each exercise session to reduce measurement error. The level of between-unit measurement error should be considered when comparing results from players wearing different GPS units.

  10. Does Distress Tolerance Moderate the Impact of Major Life Events on Psychosocial Variables and Behaviors Important in the Management of HIV?

    Science.gov (United States)

    O'Cleirigh, Conall; Ironson, Gail; Smits, Jasper A. J.

    2007-01-01

    Living with HIV involves management of multiple stressful disease-related and other life events. Distress tolerance may provide a functional, individual-based context for qualifying the established relationships between major life events and psychosocial variables important in the management of HIV. The present study provided a preliminary test of…

  11. Serial Holter ST-segment monitoring after first acute myocardial infarction. Prevalence, variability, and long-term prognostic importance of transient myocardial ischemia

    DEFF Research Database (Denmark)

    Mickley, H; Nielsen, J R; Berning, J

    1998-01-01

    Based on serial Holter monitoring performed 7 times within 3 years after a first acute myocardial infarction, we assessed the prevalence, variability and long-term clinical importance of transient myocardial ischemia (TMI) defined as episodes of ambulatory ST-segment depression. In all, 121...

  12. A stepwedge-based method for measuring breast density: observer variability and comparison with human reading

    Science.gov (United States)

    Diffey, Jenny; Berks, Michael; Hufton, Alan; Chung, Camilla; Verow, Rosanne; Morrison, Joanna; Wilson, Mary; Boggis, Caroline; Morris, Julie; Maxwell, Anthony; Astley, Susan

    2010-04-01

    Breast density is positively linked to the risk of developing breast cancer. We have developed a semi-automated, stepwedge-based method that has been applied to the mammograms of 1,289 women in the UK breast screening programme to measure breast density by volume and area. 116 images were analysed by three independent operators to assess inter-observer variability; 24 of these were analysed on 10 separate occasions by the same operator to determine intra-observer variability. 168 separate images were analysed using the stepwedge method and by two radiologists who independently estimated percentage breast density by area. There was little intra-observer variability in the stepwedge method (average coefficients of variation 3.49% - 5.73%). There were significant differences in the volumes of glandular tissue obtained by the three operators. This was attributed to variations in the operators' definition of the breast edge. For fatty and dense breasts, there was good correlation between breast density assessed by the stepwedge method and the radiologists. This was also observed between radiologists, despite significant inter-observer variation. Based on analysis of thresholds used in the stepwedge method, radiologists' definition of a dense pixel is one in which the percentage of glandular tissue is between 10 and 20% of the total thickness of tissue.

  13. Development of a scale to measure adherence to self-monitoring of blood glucose with latent variable measurement.

    Science.gov (United States)

    Wagner, J A; Schnoll, R A; Gipson, M T

    1998-07-01

    Adherence to self-monitoring of blood glucose (SMBG) is problematic for many people with diabetes. Self-reports of adherence have been found to be unreliable, and existing paper-and-pencil measures have limitations. This study developed a brief measure of SMBG adherence with good psychometric properties and a useful factor structure that can be used in research and in practice. A total of 216 adults with diabetes responded to 30 items rated on a 9-point Likert scale that asked about blood monitoring habits. In part I of the study, items were evaluated and retained based on their psychometric properties. The sample was divided into exploratory and confirmatory halves. Using the exploratory half, items with acceptable psychometric properties were subjected to a principal components analysis. In part II of the study, structural equation modeling was used to confirm the component solution with the entire sample. Structural modeling was also used to test the relationship between these components. It was hypothesized that the scale would produce four correlated factors. Principal components analysis suggested a two-component solution, and confirmatory factor analysis confirmed this solution. The first factor measures the degree to which patients rely on others to help them test and thus was named "social influence." The second component measures the degree to which patients use physical symptoms of blood glucose levels to help them test and thus was named "physical influence." Results of the structural model show that the components are correlated and make up the higher-order latent variable adherence. The resulting 15-item scale provides a short, reliable way to assess patient adherence to SMBG. Despite the existence of several aspects of adherence, this study indicates that the construct consists of only two components. This scale is an improvement on previous measures of adherence because of its good psychometric properties, its interpretable factor structure, and its

  14. On the intrinsic timescales of temporal variability in measurements of the surface solar radiation

    Science.gov (United States)

    Bengulescu, Marc; Blanc, Philippe; Wald, Lucien

    2018-01-01

    This study is concerned with the intrinsic temporal scales of the variability in the surface solar irradiance (SSI). The data consist of decennial time series of daily means of the SSI obtained from high-quality measurements of the broadband solar radiation impinging on a horizontal plane at ground level, issued from different Baseline Surface Radiation Network (BSRN) ground stations around the world. First, embedded oscillations sorted in terms of increasing timescales of the data are extracted by empirical mode decomposition (EMD). Next, Hilbert spectral analysis is applied to obtain an amplitude-modulation-frequency-modulation (AM-FM) representation of the data. The time-varying nature of the characteristic timescales of variability, along with the variations in the signal intensity, are thus revealed. A novel, adaptive null hypothesis based on the general statistical characteristics of noise is employed in order to discriminate between the different features of the data, those that have a deterministic origin and those being realizations of various stochastic processes. The data have a significant spectral peak corresponding to the yearly variability cycle and feature quasi-stochastic high-frequency variability components, irrespective of the geographical location or of the local climate. Moreover, the amplitude of this latter feature is shown to be modulated by variations in the yearly cycle, which is indicative of nonlinear multiplicative cross-scale couplings. The study has possible implications on the modeling and the forecast of the surface solar radiation, by clearly discriminating the deterministic from the quasi-stochastic character of the data, at different local timescales.

  15. Measurement and modeling of diel variability of polybrominated diphenyl ethers and chlordanes in air.

    Science.gov (United States)

    Moeckel, Claudia; Macleod, Matthew; Hungerbühler, Konrad; Jones, Kevin C

    2008-05-01

    Short-term variability of concentrations of polybrominated diphenyl ethers (PBDEs) and chlordanes in air at a semirural site in England over a 5 day period is reported. Four-hour air samples were collected during a period dominated by a high pressure system that produced stable diel (24-h) patterns of meteorological conditions such as temperature and atmospheric boundary layer height. PBDE and chlordane concentrations showed clear diel variability with concentrations in the afternoon and evening being 1.9 - 2.7 times higher than in the early morning. The measurements are interpreted using a multimedia mass balance model parametrized with forcing functions representing local temperature, atmospheric boundary layer height, wind speed and hydroxyl radical concentrations. Model results indicate that reversible, temperature-controlled air-surface exchange is the primary driver of the diel concentration pattern observed for chlordanes and PBDE 28. For higher brominated PBDE congeners (47, 99 and 100), the effect of variable atmospheric mixing height in combination with irreversible deposition on aerosol particles is dominant and explains the diel patterns almost entirely. Higher concentrations of chlordanes and PBDEs in air observed at the end of the study period could be related to likely source areas using back trajectory analysis. This is the first study to clearly document diel variability in concentrations of PBDEs in air over a period of several days. Our model analysis indicates that high daytime and low nighttime concentrations of semivolatile organic chemicals can arise from different underlying driving processes, and are not necessarily evidence of reversible air-surface exchange on a 24-h time scale.

  16. CO2 Total Column Variability From Ground-Based FTIR Measurements Over Central Mexico

    Science.gov (United States)

    Baylon, J. L.; Stremme, W.; Plaza, E.; Bezanilla, A.; Grutter, M.; Hase, F.; Blumenstock, T.

    2014-12-01

    There are now several space missions dedicated to measure greenhouse gases in order to improve the understanding of the carbon cycle. Ground based measurement sites are of great value in the validation process, however there are only a few stations in tropical latitudes. We present measurements of solar-absorption infrared spectra recorded on two locations over Central Mexico: the High-Altitude Station Altzomoni (19.12 N, 98.65 W), located in the Izta-Popo National Park outside of Mexico City; and the UNAM's Atmospheric Observatory (19.32 N, 99.17 W) in Mexico City. These measurements were performed using a high resolution Fourier transform infrared spectrometer FTIR (Bruker, HR 120/5) at Altzomoni and a moderate resolution FTIR (Bruker, Vertex 80) within the city. In this work, we present the first results for total vertical columns of CO2 derived from near-infrared spectra recorded at both locations using the retrieval code PROFFIT. We present the seasonal cycle and variability from the measurements, as well as the full diagnostics of the retrieval in order assess its quality and discuss the differences of both instruments and locations (altitudes, urban vs remote). This work aims to contribute to generate high quality datasets for satellite validation.

  17. Instrumental variables vs. grouping approach for reducing bias due to measurement error.

    Science.gov (United States)

    Batistatou, Evridiki; McNamee, Roseanne

    2008-01-01

    Attenuation of the exposure-response relationship due to exposure measurement error is often encountered in epidemiology. Given that error cannot be totally eliminated, bias correction methods of analysis are needed. Many methods require more than one exposure measurement per person to be made, but the `group mean OLS method,' in which subjects are grouped into several a priori defined groups followed by ordinary least squares (OLS) regression on the group means, can be applied with one measurement. An alternative approach is to use an instrumental variable (IV) method in which both the single error-prone measure and an IV are used in IV analysis. In this paper we show that the `group mean OLS' estimator is equal to an IV estimator with the group mean used as IV, but that the variance estimators for the two methods are different. We derive a simple expression for the bias in the common estimator which is a simple function of group size, reliability and contrast of exposure between groups, and show that the bias can be very small when group size is large. We compare this method with a new proposal (group mean ranking method), also applicable with a single exposure measurement, in which the IV is the rank of the group means. When there are two independent exposure measurements per subject, we propose a new IV method (EVROS IV) and compare it with Carroll and Stefanski's (CS IV) proposal in which the second measure is used as an IV; the new IV estimator combines aspects of the `group mean' and `CS' strategies. All methods are evaluated in terms of bias, precision and root mean square error via simulations and a dataset from occupational epidemiology. The `group mean ranking method' does not offer much improvement over the `group mean method.' Compared with the `CS' method, the `EVROS' method is less affected by low reliability of exposure. We conclude that the group IV methods we propose may provide a useful way to handle mismeasured exposures in epidemiology with or

  18. Dynamic Stall Measurements and Computations for a VR-12 Airfoil with a Variable Droop Leading Edge

    Science.gov (United States)

    Martin, P. B.; McAlister, K. W.; Chandrasekhara, M. S.; Geissler, W.

    2003-01-01

    High density-altitude operations of helicopters with advanced performance and maneuver capabilities have lead to fundamental research on active high-lift system concepts for rotor blades. The requirement for this type of system was to improve the sectional lift-to-drag ratio by alleviating dynamic stall on the retreating blade while simultaneously reducing the transonic drag rise of the advancing blade. Both measured and computational results showed that a Variable Droop Leading Edge (VDLE) airfoil is a viable concept for application to a rotor high-lift system. Results are presented for a series of 2D compressible dynamic stall wind tunnel tests with supporting CFD results for selected test cases. These measurements and computations show a dramatic decrease in the drag and pitching moment associated with severe dynamic stall when the VDLE concept is applied to the Boeing VR-12 airfoil. Test results also show an elimination of the negative pitch damping observed in the baseline moment hysteresis curves.

  19. A simple method to measure the complex permittivity of materials at variable temperatures

    Science.gov (United States)

    Yang, Xiaoqing; Yin, Yang; Liu, Zhanwei; Zhang, Di; Wu, Shiyue; Yuan, Jianping; Li, Lixin

    2017-10-01

    Measurement of the complex permittivity (CP) of a material at different temperatures in microwave heating applications is difficult and complicated. In this paper a simple and convenient method is employed to measure the CP of a material over variable temperature. In this method the temperature of a sample is increased experimentally to obtain the formula for the relationship between CP and temperature by a genetic algorithm. We chose agar solution (sample) and a Yangshao reactor (microwave heating system) to validate the reliability and feasibility of this method. The physical parameters (the heat capacity, C p , density, ρ, and thermal conductivity, k) of the sample are set as constants in the process of simulation and inversion. We analyze the influence of the variation of physical parameters with temperature on the accuracy of the inversion results. It is demonstrated that the variation of these physical parameters has little effect on the inversion results in a certain temperature range.

  20. Design and evaluation of a handheld impedance plethysmograph for measuring heart rate variability

    DEFF Research Database (Denmark)

    Kristiansen, N. K.; Fleischer, J.; Jensen, M. S.

    2005-01-01

    Heart rate variability (HRV) analysis from 10s ECGs has been shown to be reliable. However, the short examination time warrants a user-friendly system that can be used for ad-hoc examinations without normal preparation, unlike ECG. A handheld device has been developed that can measure ultra...... was performed by a digital signal processor, where the discrete heart beats were detected using a correlation algorithm that could adapt to individual pulse wave shapes to account for biological variation. The novel device was evaluated in 20 mainly young volunteers, using 10 s time-correlated ECG recordings...... as the reference method. Agreement between the two methods in measuring heart rate and root mean square of successive differences in the heart beat interval (RMSSD) was analysed using correlation coefficients (Pearson's R-2), mean differences with 95% confidence intervals and 95% limits of agreement, and Bland...

  1. Variable Speed Drive Characterization: Review of Measurement Techniques and Future Trends

    Directory of Open Access Journals (Sweden)

    Edoardo Fiorucci

    2013-01-01

    Full Text Available The significant advances in power electronics have permitted the implementation of sophisticated methods for control of electric motors. Each innovative electrical apparatus for industrial and automotive application must be correctly and exhaustively tested, both during the developing process and finally for the compliance test. The development of a new electrical system should be associated with a parallel design of an ad hoc measurement system, whose performance should be defined according to the features of the system under test. In recent years, the increasing interest for sensorless electric motor drives involved the development and implementation of a wide set of control techniques. This paper reviews the state and the trends of measurement techniques and instruments applied for the experimental characterization of variable speed drives.

  2. Variables Measured During Cardiopulmonary Exercise Testing as Predictors of Mortality in Chronic Systolic Heart Failure.

    Science.gov (United States)

    Keteyian, Steven J; Patel, Mahesh; Kraus, William E; Brawner, Clinton A; McConnell, Timothy R; Piña, Ileana L; Leifer, Eric S; Fleg, Jerome L; Blackburn, Gordon; Fonarow, Gregg C; Chase, Paul J; Piner, Lucy; Vest, Marianne; O'Connor, Christopher M; Ehrman, Jonathan K; Walsh, Mary N; Ewald, Gregory; Bensimhon, Dan; Russell, Stuart D

    2016-02-23

    Data from a cardiopulmonary exercise (CPX) test are used to determine prognosis in patients with chronic heart failure (HF). However, few published studies have simultaneously compared the relative prognostic strength of multiple CPX variables. The study sought to describe the strength of the association among variables measured during a CPX test and all-cause mortality in patients with HF with reduced ejection fraction (HFrEF), including the influence of sex and patient effort, as measured by respiratory exchange ratio (RER). Among patients (n = 2,100, 29% women) enrolled in the HF-ACTION (HF-A Controlled Trial Investigating Outcomes of exercise traiNing) trial, 10 CPX test variables measured at baseline (e.g., peak oxygen uptake [Vo2], exercise duration, percent predicted peak Vo2 [%ppVo2], ventilatory efficiency) were examined. Over a median follow-up of 32 months, there were 357 deaths. All CPX variables, except RER, were related to all-cause mortality (all p mortality. Peak Vo2 (ml·kg(-1)·min(-1)) was the strongest predictor of mortality among men (Wald chi-square: 129) and exercise duration among women (Wald chi-square: 41). Multivariable analyses showed that %ppVo2, exercise duration, and peak Vo2 (ml·kg(-1)·min(-1)) were similarly able to predict and discriminate mortality. In men, a 10% 1-year mortality rate corresponded to a peak Vo2 of 10.9 ml·kg(-1)·min(-1) versus 5.3 ml·kg(-1)·min(-1) in women. Peak Vo2, exercise duration, and % ppVo2 carried the strongest ability to predict and discriminate the likelihood of death in patients with HFrEF. The prognosis associated with a given peak Vo2 differed by sex. (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure; NCT00047437). Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  3. Identification of Muscidae (Diptera) of medico-legal importance by means of wing measurements.

    Science.gov (United States)

    Grzywacz, Andrzej; Ogiela, Jakub; Tofilski, Adam

    2017-05-01

    Cadavers attract numerous species and genera of Muscidae, both regular elements of carrion insect assemblages, and accidental visitors. Identification of adult Muscidae may be considered difficult, particularly by non-experts. Since species identification is a vital first step in the analysis of entomological material in any forensic entomology orientated experiment and real cases, various alternative methods of species identification have been proposed. We investigated possibility of semiautomated identification by means of wing measurements as an alternative for classic morphology and DNA-based approaches. We examined genus-level identification success for 790 specimens representing 13 genera of the most common European cadavers visiting Muscidae. We found 99.8% of examined specimens correctly identified to the genus-level. Without error, the following were identified: Azelia, Eudasyphora, Graphomya, Hydrotaea, Musca, Muscina, Mydaea, Neomyia, Polietes, Stomoxys and Thricops. Genus-level misidentifications were found only in Helina and Phaonia. Discrimination of examined material on the species level within Hydrotaea (318 specimens representing eight species) and Muscina (163 specimens representing four species) showed lower, yet still high average identification success, 97.2 and 98.8%, respectively. Our results revealed relatively high success in both genus and species identification of Muscidae of medico-legal importance. Semiautomated identification by means of wing measurements can be used by non-experts and does not require sophisticated equipment. This method will facilitate the identification of forensically relevant muscids in comparison to more difficult and more time-consuming identification approaches based on taxonomic keys or DNA-based methods. However, for unambiguous identification of some taxa, we recommend complementary use of identification keys.

  4. Development of hematological respiratory variables in late chicken embryos: the relative importance of incubation time and embryo mass.

    Science.gov (United States)

    Tazawa, Hiroshi; Andrewartha, Sarah J; Burggren, Warren W

    2011-07-01

    Oxygen demand increases during embryonic development, requiring an increase in red blood cells (RBCs) containing hemoglobin (Hb) to transport O(2) between the respiratory organ and systemic tissues. A thorough ontogenetic understanding of the onset and maturation of the complex regulatory processes for RBC concentration ([RBC]), Hb concentration ([Hb]), hematocrit (Hct), mean corpuscular indices (mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration ([MCHb])) is currently lacking. We hypothesize that during the last half of incubation when the respiratory organ (the chorioallantoic membrane) envelops most of the egg contents, mean corpuscular indices will stabilize. Accordingly, Hct, [RBC] and [Hb] must also all change proportionally across development. Further, we hypothesize that the hematological respiratory variables develop and mature as a function of incubation duration, independently of embryonic growth. As predicted, a similar increase in Hct (from 18.7±0.6% on day 10 (d10) to 34.1±0.5% on d19 of incubation), [RBC] (1.13±0.03×10(6)/μL to 2.50±0.03×10(6)/μL) and [Hb] (6.1±0.2 g% to 11.2±0.1 g%) occurred during d10-19. Both [RBC] and [Hb] demonstrated high linear correlation with Hct, resulting in constant [MCHb] (~33 g% from d10 to d19). The decrease in MCV (from ~165 μ(3) on d10 to ~140 μ(3) on d13) and MCH (~55 pg to ~45 pg) during d10-13, may be attributed to a changeover from larger primary to smaller secondary and adult-type erythrocytes with MCV and MCH remaining constant (~140 μ(3) and ~45 pg respectively) for the rest of the incubation period (d13-19). Hematological respiratory values on a given incubation day were identical between embryos of different masses using either natural mass variation or experimental growth acceleration, indicating that the hematological variables develop as a function of incubation time, irrespective of embryo growth. Copyright © 2011. Published by

  5. Motion capture measures variability in laryngoscopic movement during endotracheal intubation: a preliminary report.

    Science.gov (United States)

    Carlson, Jestin N; Das, Samarjit; De la Torre, Fernando; Callaway, Clifton W; Phrampus, Paul E; Hodgins, Jessica

    2012-08-01

    Success rates with emergent endotracheal intubation (ETI) improve with increasing provider experience. Few objective metrics exist to quantify differences in ETI technique between providers of various skill levels. We tested the feasibility of using motion capture videography to quantify variability in the motions of the left hand and the laryngoscope in providers with various experience. Three providers with varying levels of experience [attending physician (experienced), emergency medicine resident (intermediate), and postdoctoral student with no previous ETI experience (novice)] each performed ETI 4 times on a mannequin. Vicon, a 16-camera system, tracked the 3-dimensional orientation and movement of markers on the providers, handle of the laryngoscope, and mannequin. Attempt duration, path length of the left hand, and the inclination of the plane of the laryngoscope handle (mean square angular deviation from vertical) were calculated for each laryngoscopy attempt. We compared interattempt and interprovider variability of each measure. All ETI attempts were successful. Mean (SD) duration of laryngoscopy attempts differed between experienced [5.50 (0.68) seconds], intermediate [6.32 (1.13) seconds], and novice [12.38 (1.06) seconds] providers (P = 0.021). Mean path length of the left hand did not differ between providers (P = 0.37). Variability of the plane of the laryngoscope differed between providers: 8.3 (experienced), 28.7 (intermediate), and 54.5 (novice) degrees squared. Motion analysis can detect interprovider differences in hand and laryngoscope movements during ETI, which may be related to provider experience. This technology has potential to objectively measure training and skill in ETI.

  6. Measuring variability in trophic status in the Lake Waco/Bosque River Watershed

    Directory of Open Access Journals (Sweden)

    Rodriguez Angela D

    2008-01-01

    Full Text Available Abstract Background Nutrient management in rivers and streams is difficult due to the spatial and temporal variability of algal growth responses. The objectives of this project were to determine the spatial and seasonal in situ variability of trophic status in the Lake Waco/Bosque River watershed, determine the variability in the lotic ecosystem trophic status index (LETSI at each site as indicators of the system's nutrient sensitivity, and determine if passive diffusion periphytometers could provide threshold algal responses to nutrient enrichment. Methods We used the passive diffusion periphytometer to measure in-situ nutrient limitation and trophic status at eight sites in five streams in the Lake Waco/Bosque River Watershed in north-central Texas from July 1997 through October 1998. The chlorophyll a production in the periphytometers was used as an indicator of baseline chlorophyll a productivity and of maximum primary productivity (MPP in response to nutrient enrichment (nitrogen and phosphorus. We evaluated the lotic ecosystem trophic status index (LETSI using the ratio of baseline primary productivity to MPP, and evaluated the trophic class of each site. Results The rivers and streams in the Lake Waco/Bosque River Watershed exhibited varying degrees of nutrient enrichment over the 18-month sampling period. The North Bosque River at the headwaters (NB-02 located below the Stephenville, Texas wastewater treatment outfall consistently exhibited the highest degree of water quality impact due to nutrient enrichment. Sites at the outlet of the watershed (NB-04 and NB-05 were the next most enriched sites. Trophic class varied for enriched sites over seasons. Conclusion Seasonality played a significant role in the trophic class and sensitivity of each site to nutrients. Managing rivers and streams for nutrients will require methods for measuring in situ responses and sensitivities to nutrient enrichment. Nutrient enrichment periphytometers show

  7. Measuring variability in trophic status in the Lake Waco/Bosque River Watershed.

    Science.gov (United States)

    Rodriguez, Angela D; Matlock, Marty D

    2008-01-11

    Nutrient management in rivers and streams is difficult due to the spatial and temporal variability of algal growth responses. The objectives of this project were to determine the spatial and seasonal in situ variability of trophic status in the Lake Waco/Bosque River watershed, determine the variability in the lotic ecosystem trophic status index (LETSI) at each site as indicators of the system's nutrient sensitivity, and determine if passive diffusion periphytometers could provide threshold algal responses to nutrient enrichment. We used the passive diffusion periphytometer to measure in-situ nutrient limitation and trophic status at eight sites in five streams in the Lake Waco/Bosque River Watershed in north-central Texas from July 1997 through October 1998. The chlorophyll a production in the periphytometers was used as an indicator of baseline chlorophyll a productivity and of maximum primary productivity (MPP) in response to nutrient enrichment (nitrogen and phosphorus). We evaluated the lotic ecosystem trophic status index (LETSI) using the ratio of baseline primary productivity to MPP, and evaluated the trophic class of each site. The rivers and streams in the Lake Waco/Bosque River Watershed exhibited varying degrees of nutrient enrichment over the 18-month sampling period. The North Bosque River at the headwaters (NB-02) located below the Stephenville, Texas wastewater treatment outfall consistently exhibited the highest degree of water quality impact due to nutrient enrichment. Sites at the outlet of the watershed (NB-04 and NB-05) were the next most enriched sites. Trophic class varied for enriched sites over seasons. Seasonality played a significant role in the trophic class and sensitivity of each site to nutrients. Managing rivers and streams for nutrients will require methods for measuring in situ responses and sensitivities to nutrient enrichment. Nutrient enrichment periphytometers show significant potential for use in nutrient gradient studies.

  8. Mini-UAV Based Sensory System for Measuring Environmental Variables in Greenhouses

    Directory of Open Access Journals (Sweden)

    Juan Jesús Roldán

    2015-02-01

    Full Text Available This paper describes the design, construction and validation of a mobile sensory platform for greenhouse monitoring. The complete system consists of a sensory system on board a small quadrotor (i.e., a four rotor mini-UAV. The goals of this system include taking measures of temperature, humidity, luminosity and CO2 concentration and plotting maps of these variables. These features could potentially allow for climate control, crop monitoring or failure detection (e.g., a break in a plastic cover. The sensors have been selected by considering the climate and plant growth models and the requirements for their integration onboard the quadrotor. The sensors layout and placement have been determined through a study of quadrotor aerodynamics and the influence of the airflows from its rotors. All components of the system have been developed, integrated and tested through a set of field experiments in a real greenhouse. The primary contributions of this paper are the validation of the quadrotor as a platform for measuring environmental variables and the determination of the optimal location of sensors on a quadrotor.

  9. Mini-UAV based sensory system for measuring environmental variables in greenhouses.

    Science.gov (United States)

    Roldán, Juan Jesús; Joossen, Guillaume; Sanz, David; del Cerro, Jaime; Barrientos, Antonio

    2015-02-02

    This paper describes the design, construction and validation of a mobile sensory platform for greenhouse monitoring. The complete system consists of a sensory system on board a small quadrotor (i.e., a four rotor mini-UAV). The goals of this system include taking measures of temperature, humidity, luminosity and CO2 concentration and plotting maps of these variables. These features could potentially allow for climate control, crop monitoring or failure detection (e.g., a break in a plastic cover). The sensors have been selected by considering the climate and plant growth models and the requirements for their integration onboard the quadrotor. The sensors layout and placement have been determined through a study of quadrotor aerodynamics and the influence of the airflows from its rotors. All components of the system have been developed, integrated and tested through a set of field experiments in a real greenhouse. The primary contributions of this paper are the validation of the quadrotor as a platform for measuring environmental variables and the determination of the optimal location of sensors on a quadrotor.

  10. Associations Between Step Duration Variability and Inertial Measurement Unit Derived Gait Characteristics.

    Science.gov (United States)

    Rantalainen, Timo; Hart, Nicolas H; Nimphius, Sophia; Wundersitz, Daniel W

    2016-08-01

    Inertial measurement units (IMU) provide a convenient tool for gait stability assessment. However, it is unclear how various gait characteristics relate to each other and whether gait characteristics can be obtained from resultant acceleration. Therefore, step duration variability was measured in treadmill walking from 39 young ambulant volunteers (age 24.2 [± 2.5] y; height 1.79 [± 0.09] m; mass 71.6 [± 12.0] kg) using motion capture. Accelerations and gyrations were simultaneously recorded with an IMU. Harmonic ratio, maximum Lyapunov exponents, and multiscale sample entropy (MSE) were calculated. Step duration variability was positively associated with MSE with coarseness levels = 3-6 (r = -.33 to -.42, P ≤ .045). Harmonic ratio and MSE with all coarseness levels were negatively associated (r = -.45 to -.57, P ≤ .004). The MSE with coarseness level = 2 was negatively associated with short-term maximum Lyapunov exponents (r = -.32, P = .047). The agreement between resultant and vertical acceleration derived gait characteristics was excellent (ICC = 0.97-0.99). In conclusion, MSE with varying coarseness levels was associated with the other gait characteristics evaluated in the study. Resultant and vertical acceleration derived results had excellent agreement, which suggests that resultant acceleration is a viable alternative to considering the acceleration dimensions independently.

  11. The non-contact measure of the heart rate variability by laser Doppler vibrometry: comparison with electrocardiography

    Science.gov (United States)

    Cosoli, G.; Casacanditella, L.; Tomasini, E. P.; Scalise, L.

    2016-06-01

    The assessment of the heart rate variability (HRV) is of utmost importance, being one of the most promising markers of the activity of the autonomic nervous system and associated to cardiovascular mortality. Different signals can be used to perform HRV, primarily electrocardiography (ECG), photoplethysmography (PPG), phonocardiography (PCG) or vibrocardiography (VCG), since the fundamental aspect is the individuation of a periodic feature strictly correlated with cardiac activity (i.e. R-peak in ECG or the first sound in PCG). In this work, the authors demonstrate that the VCG performances in HRV analysis are sufficiently accurate if compared to the ones measured by ECG (i.e. standard methodology); moreover, the authors want to prove the feasibility of such measurement in correspondence of different measurement points (i.e. carotid artery—which is the typical VCG measurement point—and the radial artery on the wrist)1. Results show that VCG has a mean deviation of  <1 bpm with respect to ECG in heart rate (HR) measurement; carotid artery is the most accurate site for the assessment, but also the radial artery is a valid site, even if with a reduced SNR. With regards to HRV parameters, the mean percentage deviation is  <10% in correspondence of carotid artery, and  ≈16% for the radial artery. So, VCG allows for non-contact monitoring of the cardiac activity.

  12. Circumpolar analysis of the Adélie Penguin reveals the importance of environmental variability in phenological mismatch

    Science.gov (United States)

    Youngflesh, Casey; Jenouvrier, Stephanie; Li, Yun; Ji, Rubao; Ainley, David G.; Ballard, Grant; Barbraud, Christophe; Delord, Karine; Dugger, Catherine; Emmerson, Loiuse M.; Fraser, William R.; Hinke, Jefferson T.; Lyver, Phil O'B.; Olmastroni, Silvia; Southwell, Colin J.; Trivelpiece, Susan G.; Trivelpiece, Wayne Z.; Lynch, Heather J.

    2017-01-01

    Evidence of climate-change-driven shifts in plant and animal phenology have raised concerns that certain trophic interactions may be increasingly mismatched in time, resulting in declines in reproductive success. Given the constraints imposed by extreme seasonality at high latitudes and the rapid shifts in phenology seen in the Arctic, we would also expect Antarctic species to be highly vulnerable to climate-change-driven phenological mismatches with their environment. However, few studies have assessed the impacts of phenological change in Antarctica. Using the largest database of phytoplankton phenology, sea-ice phenology, and Adélie Penguin breeding phenology and breeding success assembled to date, we find that, while a temporal match between Penguin breeding phenology and optimal environmental conditions sets an upper limit on breeding success, only a weak relationship to the mean exists. Despite previous work suggesting that divergent trends in Adélie Penguin breeding phenology are apparent across the Antarctic continent, we find no such trends. Furthermore, we find no trend in the magnitude of phenological mismatch, suggesting that mismatch is driven by interannual variability in environmental conditions rather than climate-change-driven trends, as observed in other systems. We propose several criteria necessary for a species to experience a strong climate-change-driven phenological mismatch, of which several may be violated by this system.

  13. Distance between Anterior Commissure and the First Tracheal Ring: An Important New Clinical Laryngotracheal Measurement

    Directory of Open Access Journals (Sweden)

    Ehsan Khadivi

    2015-05-01

    Full Text Available Introduction: The distance between the anterior commissure of the larynx and the first tracheal ring (AC.T. distance is of great importance in laryngotracheal surgeries.  The amount of narrowing of the subglottic airway is used as a quantitative mean to determine whether the lesion is subglottic or has extended to the trachea and therefore helps in the prediction of the final prognosis.   Materials and Methods: In this study, the larynx was exposed by direct laryngoscopy under general anesthesia. The case was considered to be difficult because the exposure did not optimally reveal the anterior commissure, therefore a cricoid tape or anterior commissure laryngoscope was used. A zero degree Hopkins lens was used to view the anterior commissure and the first tracheal ring. Special markers were used to mark the two points with the distance between those being considered as the AC.T. distance. The relationship between AC.T. distance and the patient's age, sex, BMI, and laryngeal exposure condition during laryngoscopy was also studied.   Results: Eighty-two patients participated in this study. The mean AC.T. distance was measured and was found to be 32.67±3.34 mm in males and 29.80± 3.00 mm in females. This difference was statistically significant between the two groups (P

  14. Health status measurement in COPD: the minimal clinically important difference of the clinical COPD questionnaire

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    van den Berg JWK

    2006-04-01

    Full Text Available Abstract Background Patient-reported outcomes (PRO questionnaires are being increasingly used in COPD clinical studies. The challenge facing investigators is to determine what change is significant, ie what is the minimal clinically important difference (MCID. This study aimed to identify the MCID for the clinical COPD questionnaire (CCQ in terms of patient referencing, criterion referencing, and by the standard error of measurement (SEM. Methods Patients were ≥40 years of age, diagnosed with COPD, had a smoking history of >10 pack-years, and were participating in a randomized, controlled clinical trial comparing intravenous and oral prednisolone in patients admitted with an acute exacerbation of COPD. The CCQ was completed on Days 1–7 and 42. A Global Rating of Change (GRC assessment was taken to establish the MCID by patient referencing. For criterion referencing, health events during a period of 1 year after Day 42 were included in this analysis. Results 210 patients were recruited, 168 completed the CCQ questionnaire on Day42. The MCID of the CCQ total score, as indicated by patient referencing in terms of the GRC, was 0.44. The MCID of the CCQ in terms of criterion referencing for the major outcomes was 0.39, and calculation of the SEM resulted in a value of 0.21. Conclusion This investigation, which is the first to determine the MCID of a PRO questionnaire via more than one approach, indicates that the MCID of the CCQ total score is 0.4.

  15. Variability in Patellofemoral Alignment Measurements on MRI: Influence of Knee Position.

    Science.gov (United States)

    Marquez-Lara, Alejandro; Andersen, Jason; Lenchik, Leon; Ferguson, Cristin M; Gupta, Pushpender

    2017-05-01

    The purpose of this study was to determine the variability of distances between four distinct anatomic landmarks used for the evaluation of patellofemoral alignment while implementing controlled changes in patient positioning during MRI. Limited MRI was performed of 12 knees in healthy volunteers (10 men, two women; mean age, 28 years) with the knees in four different positions. The four landmarks used were TT (the most anterior point of the osseous tibial tubercle), TG (the nadir of the cartilaginous trochlear groove), PT (the center of the patellar tendon insertion on the tibia), and PCL (the medial border of the posterior cruciate ligament at its insertion along the posterior tibia). TT-TG, PT-TG, TT-PCL, and PT-PCL distances were measured on the MR images. Each distance was measured with the knee at maximum patient comfort (rest), full extension, 15° of flexion, and 30° of flexion. Linear mixed models with random intercepts were implemented to determine variability between measurements and knee position. In general, measurements based on anatomic landmark and knee position varied greatly. The greatest variability in different knee positions was seen in mean TT-TG and PT-TG distances ± SD (TT-TG: rest, 18.1 ± 7.9 mm; full extension, 17.3 ± 5.3 mm; 15° of flexion, 11.4 ± 5.7 mm; 30° of flexion, 11.7 ± 6.0 mm; intraclass correlation coefficient [ICC] = 0.539; PT-TG: rest, 18.1 ± 6.3 mm; full extension, 17.9 ± 4.7 mm; 15° of flexion, 13.2 ± 5.2 mm; 30° of flexion, 11.8 ± 4.3 mm; ICC = 0.633). In contrast, knee position did not significantly affect distances for TT-PCL and PT-PCL (TT-PCL: rest, 23.5 ± 6.8 mm; full extension, 20.5 ± 5.5 mm; 15° of flexion, 22.8 ± 6.2 mm; 30° of flexion, 22.8 ± 6.7 mm; ICC = 0.484; PTPCL: rest, 23.4 ± 5.3 mm; full extension, 21.5 ± 4.5 mm; 15° of flexion, 22.3 ± 4.3 mm; 30° of flexion, 23.1 ± 4.8 mm; ICC = 0.509). On MRI, TT-PCL and PT-PCL measurements have significantly less variability compared with TT

  16. Measuring trunk motions in industry: variability due to task factors, individual differences, and the amount of data collected.

    Science.gov (United States)

    Allread, W G; Marras, W S; Burr, D L

    2000-06-01

    The focus of this study was to determine the amount of data needed to ensure sufficient accuracy in estimating mean trunk motions of employees performing industrial manual materials handling tasks. Over 450 tasks were selected, in which the load weight and the vertical start and destination heights of the activity remained constant throughout the task. Data were collected as employees did their work at the job site, using the Lumbar Motion Monitor. Variance components were estimated in a hierarchical design and used to compute standard errors of mean trunk kinematic measures. These analyses found task-to-task variation to be much larger than the variability due to either multiple employees performing the same task or to repetitive movements within a task. Also, it was found that no significant reduction in the standard errors occurred when data were gathered for more than three employees and three repetitions of each task by an employee. This study indicates that the vast majority of variability in mean trunk motions is accounted for by the design of work tasks, and variations due to repeated cycles of a task or to employees are rather minor. It is also important as a basis for future work on modelling low-back disorder risk based on a job's trunk kinematic measures.

  17. The study of the potato’s life-cycle phases important to the increase of the individual variability

    Directory of Open Access Journals (Sweden)

    Zsuzsanna NEMES

    2008-05-01

    Full Text Available The authors describe the practical importance of the knowledge of the potato’s life-cycle phases. There was made a research about the life-cycle of some varieties created at the Potato Research and Development Station Targu-Secuiesc, aiming at the proper management of the crop care, the irrigation and fertilization of the crops, depending on their objective.The varieties Redsec, Ioana, Luiza and Star are semi-late maturing varieties, with a vegetative period of 80 – 110 days, each of them displaying certain specific features during the growth and development period that are highlighted in the present research paper.

  18. The study of the potato’s life-cycle phases important to the increase of the individual variability

    OpenAIRE

    Zsuzsanna NEMES; Anca BACIU; Daniela POPA; Luiza MIKE; Adriana PETRUS–VANCEA; Oana DANCI

    2008-01-01

    The authors describe the practical importance of the knowledge of the potato’s life-cycle phases. There was made a research about the life-cycle of some varieties created at the Potato Research and Development Station Targu-Secuiesc, aiming at the proper management of the crop care, the irrigation and fertilization of the crops, depending on their objective.The varieties Redsec, Ioana, Luiza and Star are semi-late maturing varieties, with a vegetative period of 80 – 110 days, each of them dis...

  19. Irrigation as an important anthropogenic forcing on the mean and intra-seasonal variability of Indian summer monsoon

    Science.gov (United States)

    Agrawal, Shubhi; Chakraborty, Arindam; Karmakar, Nirupam; Moulds, Simon; Mijic, Ana; Buytaert, Wouter

    2017-04-01

    Decreasing trend in rainfall in the last few decades over Indo-Gangetic Plains of northern India as seen from ground-based observations, parallels stressed ground water resources, with irrigation utilising up to 90%. The decrease in mean rainfall is co-incidental with an increasing trend in irrigation. In this work, we have analysed the effect of the extensive irrigation over Gangetic Plains (GP) on monsoon climate. In the first step, the effect of irrigation on soil moisture was accessed using a high-resolution land surface model (JULES). The model was run over Gangetic basin in two scenarios: with and without irrigation. It was seen that the mean soil moisture over GP in the irrigated scenario is higher as compared to non-irrigated scenario. These soil moisture fields were then used as forcing to a state-of-the-art general circulation model with realistic land-atmosphere coupling. A decrease in June-September precipitation over GP, significant at 95% level, is noted in the model simulation with irrigation as compared to simulation without irrigation. In specific, these changes show a remarkable similarity to the long-term trend in observed rainfall spatial pattern. Moreover, weakening of the variability of intra-seasonal oscillations in the high (10-20 days) and low (30-60 days) frequency bands is noted with irrigation. Our results suggest that with shrinking ground water resources in the GP region and a decline in the summer precipitation, the water crisis could exacerbate, with irrigation contributing in a positive feedback mechanism on these tendencies.

  20. On measuring the response of mesophyll conductance to carbon dioxide with the variable J method.

    Science.gov (United States)

    Gilbert, Matthew Edmund; Pou, Alícia; Zwieniecki, Maciej Andrzej; Holbrook, N Michele

    2012-01-01

    The response of mesophyll conductance to CO(2) (g(m)) to environmental variation is a challenging parameter to measure with current methods. The 'variable J' technique, used in the majority of studies of g(m), assumes a one-to-one relationship between photosystem II (PSII) fluorescence and photosynthesis under non-photorespiratory conditions. When calibrating this relationship for Populus trichocarpa, it was found that calibration relationships produced using variation in light and CO(2) were not equivalent, and in all cases the relationships were non-linear-something not accounted for in previous studies. Detailed analyses were performed of whether different calibration procedures affect the observed g(m) response to CO(2). Past linear and assumed calibration methods resulted in systematic biases in the fluorescence estimates of electron transport. A sensitivity analysis on modelled data (where g(m) was held constant) demonstrated that biases in the estimation of electron transport as small as 2% (∼0.5 μmol m(-2) s(-1)) resulted in apparent changes in the relationship of g(m) to CO(2) of similar shape and magnitude to those observed with past calibration techniques. This sensitivity to biases introduced during calibrations leads to results where g(m) artefactually decreases with CO(2), assuming that g(m) is constant; if g(m) responds to CO(2), then biases associated with past calibration methods would lead to overestimates of the slope of the relationship. Non-linear calibrations were evaluated; these removed the bias present in past calibrations, but the method remained sensitive to measurement errors. Thus measurement errors, calibration non-linearities leading to bias, and the sensitivity of variable J g(m) hinders its use under conditions of varying CO(2) or light.

  1. System importance measures: A new approach to resilient systems-of-systems

    Science.gov (United States)

    Uday, Payuna

    Resilience is the ability to withstand and recover rapidly from disruptions. While this attribute has been the focus of research in several fields, in the case of system-of-systems (SoSs), addressing resilience is particularly interesting and challenging. As infrastructure SoSs, such as power, transportation, and communication networks, grow in complexity and interconnectivity, measuring and improving the resilience of these SoSs is vital in terms of safety and providing uninterrupted services. The characteristics of systems-of-systems make analysis and design of resilience challenging. However, these features also offer opportunities to make SoSs resilient using unconventional methods. In this research, we present a new approach to the process of resilience design. The core idea behind the proposed design process is a set of system importance measures (SIMs) that identify systems crucial to overall resilience. Using the results from the SIMs, we determine appropriate strategies from a list of design principles to improve SoS resilience. The main contribution of this research is the development of an aid to design that provides specific guidance on where and how resources need to be targeted. Based on the needs of an SoS, decision-makers can iterate through the design process to identify a set of practical and effective design improvements. We use two case studies to demonstrate how the SIM-based design process can inform decision-making in the context of SoS resilience. The first case study focuses on a naval warfare SoS and describes how the resilience framework can leverage existing simulation models to support end-to-end design. We proceed through stages of the design approach using an agent-based model (ABM) that enables us to demonstrate how simulation tools and analytical models help determine the necessary inputs for the design process and, subsequently, inform decision-making regarding SoS resilience. The second case study considers the urban

  2. The importance of measuring toothpaste abrasivity in both a quantitative and qualitative way.

    Science.gov (United States)

    Johannsen, Gunnar; Tellefsen, Georg; Johannsen, Annsofi; Liljeborg, Anders

    2013-01-01

    To evaluate the relative abrasivity of different toothpastes and polishing pastes both qualitatively and quantitatively. Acrylic plates were exposed to brushing in a brushing machine with a toothpaste/water slurry for 1 and 6 h. Twelve different toothpastes were used and also four different polishing pastes. The results were evaluated using a profilometer after 1 and 6 h of brushing (corresponding to 2000 and 12 000 double strokes, respectively). A surface roughness value (Ra-value) and also a volume loss value were calculated from the profilometer measurements. These values were then correlated to each other. An unpaired t-test for the difference in the abrasion values between the toothpastes and the abrasion values over time was used. The polishing paste RDA® 170 yielded higher Ra-values than RDA 250®, both after 1 and 6 h of brushing (1.01 ± 0.22 and 8.99 ± 1.55 compared to 0.63 ± 0.26 and 7.83 ± 5.89, respectively) as well as volume loss values (3.71 ± 0.17 and 20.20 ± 2.41 compared to 2.15 ± 1.41 and 14.79 ± 11.76, respectively), thus poor correlations between the RDA and Ra and Volume loss values were shown. Among the toothpastes, Apotekets® showed the highest Ra value after 1 h of brushing and Pepsodent® whitening after 6 h of brushing. Pepsodent® whitening also showed the highest volume loss values, both after 1 and 6 h of brushing. This study emphasizes the importance of not only considering the RDA value, but also a roughness value, when describing the abrasivity of a toothpaste. Furthermore, it can be concluded that so called 'whitening' toothpastes do not necessarily have a higher abrasive effect than other toothpastes.

  3. Recent Methods for Measuring Dopamine D3 receptor Occupancy In Vivo: Importance for Drug Development

    Directory of Open Access Journals (Sweden)

    Bernard eLe Foll

    2014-07-01

    Full Text Available There is considerable interest in developing highly selective dopamine D3 receptor ligands for a variety of mental health disorders. Dopamine D3 receptors have been implicated in Parkinson’s Disease, schizophrenia, anxiety, depression, and substance use disorders. The most concrete evidence suggests a role for the D3 receptor in drug-seeking behaviors. D3 receptors are a subtype of D2 receptors, and traditionally the functional role of these two receptors has been difficult to differentiate. Over the past 10-15 years a number of compounds selective for D3 over D2 receptors have been developed. However, translating these findings into clinical research has been difficult as many of these compounds cannot be used in humans. Therefore, the functional data involving the D3 receptor in drug addiction mostly comes from preclinical studies. Recently, with the advent of [11C]-(+-PHNO, it has become possible to image D3 receptors in the human brain with increased selectivity and sensitivity. This is a significant innovation over traditional methods such as [11C]-raclopride that cannot differentiate between D2 and D3 receptors. The use of [11C]-(+-PHNO will allow for further delineation of the role of D3 receptors. Here, we review recent evidence that the role of the D3 receptor has functional importance and is distinct from the role of the D2 receptor. We then introduce the utility of analyzing [11C]-(+-PHNO binding by region of interest. This novel methodology can be used in preclinical and clinical approaches for the measurement of occupancy of both D3 and D2 receptors. Evidence that [11C]-(+-PHNO can provide insights into the function of D3 receptors in addiction is also presented.

  4. On measuring bird habitat: influence of observer variability and sample size

    Science.gov (United States)

    William M. Block; Kimberly A. With; Michael L. Morrison

    1987-01-01

    We studied the effects of observer variability when estimating vegetation characteristics at 75 0.04-ha bird plots. Observer estimates were significantly different for 31 of 49 variables. Multivariate analyses showed significant interobserver differences for five of the seven classes of variables studied. Variable classes included the height, number, and diameter of...

  5. Variable speed rotary compressor and adjustable speed drive efficiencies measured in the laboratory

    Science.gov (United States)

    Miller, W. A.

    Two state-of-the-art variable-speed rotary compressors, of nominal one ton cooling capacity, were instrumented and tested in the laboratory. Both compressors were identical except for their respective variable-speed drive systems (i.e., motor and inverter). One compressor had an inverter driven induction motor (IDIM) drive, and the other had a permanent magnet electronically commutated motor drive (PM-ECM). The laboratory study evaluated the compressor's efficiency under representative variable-speed conditions. Testing was conducted as a function of compressor drive frequency and of refrigerant condensing and evaporating conditions. Saturated refrigerant conditions, inlet superheat, and subcooling were controlled using a secondary refrigerant calorimeter. Spectrum analysis was conducted on the current input to one phase of the three-phase drive systems to measure motor speed and characterize harmonic content of the inverters. An optimal volt per Hz ratio was determined at 120-, 90-, 60-, and 30-Hz drive frequencies and at different load conditions for the rotary with induction motor as driven by a PWM inverter and also by a motor generator set (ideal induction motor drive). Variation of voltage input to the compressor had the largest effect at the lowest drive frequency (30Hz). A 5 percent variation about the optimal voltage at 30 Hz frequency caused a roughly 5 percent drop in compressor isentropic efficiency. Calorimeter data were used to develop modulating compressor and drive system performance maps. Performances of the two compressors were compared and the rotary with PM-ECM drive showed better efficiency trends at 30-Hz drive frequency. Above the 30-Hz drive frequency no clear advantage was observed for the PM-ECM vs the IDIM, possibly due to oversizing of the PM-ECM inverter.

  6. MEASURING X-RAY VARIABILITY IN FAINT/SPARSELY SAMPLED ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Allevato, V. [Department of Physics, University of Helsinki, Gustaf Haellstroemin katu 2a, FI-00014 Helsinki (Finland); Paolillo, M. [Department of Physical Sciences, University Federico II, via Cinthia 6, I-80126 Naples (Italy); Papadakis, I. [Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, 71003 Heraklion (Greece); Pinto, C. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584-CA Utrecht (Netherlands)

    2013-07-01

    We study the statistical properties of the normalized excess variance of variability process characterized by a ''red-noise'' power spectral density (PSD), as in the case of active galactic nuclei (AGNs). We perform Monte Carlo simulations of light curves, assuming both a continuous and a sparse sampling pattern and various signal-to-noise ratios (S/Ns). We show that the normalized excess variance is a biased estimate of the variance even in the case of continuously sampled light curves. The bias depends on the PSD slope and on the sampling pattern, but not on the S/N. We provide a simple formula to account for the bias, which yields unbiased estimates with an accuracy better than 15%. We show that the normalized excess variance estimates based on single light curves (especially for sparse sampling and S/N < 3) are highly uncertain (even if corrected for bias) and we propose instead the use of an ''ensemble estimate'', based on multiple light curves of the same object, or on the use of light curves of many objects. These estimates have symmetric distributions, known errors, and can also be corrected for biases. We use our results to estimate the ability to measure the intrinsic source variability in current data, and show that they could also be useful in the planning of the observing strategy of future surveys such as those provided by X-ray missions studying distant and/or faint AGN populations and, more in general, in the estimation of the variability amplitude of sources that will result from future surveys such as Pan-STARRS and LSST.

  7. Coronary CT Angiography: Variability of CT Scanners and Readers in Measurement of Plaque Volume.

    Science.gov (United States)

    Symons, Rolf; Morris, Justin Z; Wu, Colin O; Pourmorteza, Amir; Ahlman, Mark A; Lima, João A C; Chen, Marcus Y; Mallek, Marissa; Sandfort, Veit; Bluemke, David A

    2016-12-01

    Purpose To determine reader and computed tomography (CT) scan variability for measurement of coronary plaque volume. Materials and Methods This HIPAA-compliant study followed Standards for Reporting of Diagnostic Accuracy guidelines. Baseline coronary CT angiography was performed in 40 prospectively enrolled subjects (mean age, 67 years ± 6 [standard deviation]) with asymptomatic hyperlipidemia by using a 320-detector row scanner (Aquilion One Vision; Toshiba, Otawara, Japan). Twenty of these subjects underwent coronary CT angiography repeated on a separate day with the same CT scanner (Toshiba, group 1); 20 subjects underwent repeat CT performed with a different CT scanner (Somatom Force; Siemens, Forchheim, Germany [group 2]). Intraclass correlation coefficients (ICCs) and Bland-Altman analysis were used to assess interreader, intrareader, and interstudy reproducibility. Results Baseline and repeat coronary CT angiography scans were acquired within 19 days ± 6. Interreader and intrareader agreement rates were high for total, calcified, and noncalcified plaques for both CT scanners (all ICCs ≥ 0.96) without bias. Scanner variability was ±18.4% (coefficient of variation) with same-vendor follow-up. However, scanner variability increased to ±29.9% with different-vendor follow-up. The sample size to detect a 5% change in noncalcified plaque volume with 90% power and an α error of .05 was 286 subjects for same-CT scanner follow-up and 753 subjects with different-vendor follow-up. Conclusion State-of-the-art coronary CT angiography with same-vendor follow-up has good scan-rescan reproducibility, suggesting a role of coronary CT angiography in monitoring coronary artery plaque response to therapy. Differences between coronary CT angiography vendors resulted in lower scan-rescan reproducibility. (©) RSNA, 2016 Online supplemental material is available for this article.

  8. Differences between measured and linearly interpolated synoptic variables over a 12-h period during AVE 4

    Science.gov (United States)

    Dupuis, L. R.; Scoggins, J. R.

    1979-01-01

    Results of analyses revealed that nonlinear changes or differences formed centers or systems, that were mesosynoptic in nature. These systems correlated well in space with upper level short waves, frontal zones, and radar observed convection, and were very systematic in time and space. Many of the centers of differences were well established in the vertical, extending up to the tropopause. Statistical analysis showed that on the average nonlinear changes were larger in convective areas than nonconvective regions. Errors often exceeding 100 percent were made by assuming variables to change linearly through a 12-h period in areas of thunderstorms, indicating that these nonlinear changes are important in the development of severe weather. Linear changes, however, accounted for more and more of an observed change as the time interval (within the 12-h interpolation period) increased, implying that the accuracy of linear interpolation increased over larger time intervals.

  9. Resolving key drivers of variability through an important circulation choke point in the western Mediterranean Sea; using gliders, models & satellite remote sensing

    Science.gov (United States)

    Heslop, Emma; Aguiar, Eva; Mourre, Baptiste; Juza, Mélanie; Escudier, Romain; Tintoré, Joaquín

    2017-04-01

    The Ibiza Channel plays an important role in the circulation of the Western Mediterranean Sea, it governs the north/south exchange of different water masses that are known to affect regional ecosystems and is influenced by variability in the different drivers that affect sub-basins to the north (N) and south (S). A complex system. In this study we use a multi-platform approach to resolve the key drivers of this variability, and gain insight into the inter-connection between the N and S of the Western Mediterranean Sea through this choke point. The 6-year glider time series from the quasi-continuous glider endurance line monitoring of the Ibiza Channel, undertaken by SOCIB (Balearic Coastal Ocean observing and Forecasting System), is used as the base from which to identify key sub-seasonal to inter-annual patterns and shifts in water mass properties and transport volumes. The glider data indicates the following key components in the variability of the N/S flow of different water mass through the channel; regional winter mode water production, change in intermediate water mass properties, northward flows of a fresher water mass and the basin-scale circulation. To resolve the drivers of these components of variability, the strength of combining datasets from different sources, glider, modeling, altimetry and moorings, is harnessed. To the north atmospheric forcing in the Gulf of Lions is a dominant driver, while to the south the mesoscale circulation patterns of the Atlantic Jet and Alboran gyres dominate the variability but do not appear to influence the fresher inflows. Evidence of a connection between the northern and southern sub-basins is however indicated. The study highlights importance of sub-seasonal variability and the scale of rapid change possible in the Mediterranean, as well as the benefits of leveraging high resolution glider datasets within a multi-platform and modelling study.

  10. On Measuring the Criticality of Various Variables and Processes in Organization Information Systems: Proposed Methodological Procedure

    Directory of Open Access Journals (Sweden)

    Jagdish PATHAK

    2010-01-01

    Full Text Available This paper proposes methodological procedures to be used by the accounting, organizational and managerial researchers and executives to ascertain the criticality of the variables and the processes in the measurement of management control system. We have restricted the validation of proposed methods to the extraction of critical success factors (CSF in this study. We have also provided a numerical illustration and tested our methodological procedures using a dataset of an empirical study conducted for the purpose of ascertaining the CSFs. The proposed methods can be used by the researchers in accounting, organizational information systems, economics, and business and also in other relevant disciplines of organizational sciences. The main contribution of this paper is the extension of Rockart’s work [33] on critical success factors. We have extended the theory of CSF beyond the initially suggested domain of information into management control system decision making. The methodological procedures developed by us are expected to enrich the literature of analytical and empirical studies in accounting and organizational areas where it can prove helpful in understanding the criticality of individual variables, processes, methods or success factors.

  11. Within-Session Stability of Short-Term Heart Rate Variability Measurement

    Directory of Open Access Journals (Sweden)

    Cipryan Lukas

    2016-04-01

    Full Text Available The primary aim of this study was to assess the retest stability of the short-term heart rate variability (HRV measurement performed within one session and without the use of any intervention. Additionally, a precise investigation of the possible impact of intrinsic biological variation on HRV reliability was also performed. First, a single test-retest HRV measurement was conducted with 20-30 min apart from one another. Second, the HRV measurement was repeated in ten non-interrupted consecutive intervals. The lowest typical error (CV = 21.1% was found for the square root of the mean squared differences of successive RR intervals (rMSSD and the highest for the low frequency power (PLF (CV = 93.9%. The standardized changes in the mean were trivial to small. The correlation analysis revealed the highest level for ln rMSSD (ICC = 0.87, while ln PLF represented the worst case (ICC = 0.59. The reliability indices for ln rMSSD in 10 consecutive intervals improved (CV = 9.9%; trivial standardized changes in the mean; ICC = 0.96. In conclusion, major differences were found in the reliability level between the HRV indices. The rMSSD demonstrated the highest reliability level. No substantial influence of intrinsic biological variation on the HRV reliability was observed.

  12. Past and present variability of the solar-terrestrial system: measurement, data analysis and theoretical models

    Energy Technology Data Exchange (ETDEWEB)

    Cini Castagnoli, G.; Provenzale, A. [eds.

    1997-12-31

    The course Past and present variability of the solar-terrestrial system: measurement, data analysis and theoretical models is explicitly devoted to these issues. A solar cycle ago, in summer 1985, G. Cini organized a similar school, in a time when this field was in a very early stage of development and definitely fewer high-quality measurements were available. After eleven years, the field has grown toward becoming a robust scientific discipline, new data have been obtained, and new ideas have been proposed by both solar physicists and climate dynamicists. For this reason, the authors felt that it was the right time to organize a new summer school, with the aim of formalizing the developments that have taken place during these years, and also for speculating and maybe dreaming of new results that will be achieved in the upcoming years. The papers of the lectures have now been collected in this volume. First, in order to know what the authors talking about, they need to obtain reliable data from terrestrial archives,and to properly date the records that have been measured. To these crucial aspects is devoted the first part of the book, dealing with various types of proxy data and with the difficult issue of the dating of the records.

  13. Measurement of heart rate variability and stress evaluation by using microwave reflectometric vital signal sensing

    Science.gov (United States)

    Nagae, Daisuke; Mase, Atsushi

    2010-09-01

    In this paper, we present two robust signal processing techniques for stress evaluation using a microwave reflectometric cardiopulmonary sensing instrument. These techniques enable the heart rate variability (HRV) to be recovered from measurements of body-surface dynamic motion, which is subsequently used for the stress evaluation. Specifically, two novel elements are introduced: one is a reconfiguration of the HRV from the cross-correlation function between a measurement signal and a template signal which is constructed by averaging periodic component over a measurement time. The other is a reconstruction of the HRV from the time variation of the heartbeat frequency; this is evaluated by a repetition of the maximum entropy method. These two signal processing techniques accomplish the reconstruction of the HRV, though they are completely different algorithms. For validations of our model, an experimental setup is presented and several sets of experimental data are analyzed using the two proposed signal processing techniques, which are subsequently used for the stress evaluation. The results presented herein are consistent with electrocardiogram data.

  14. Relative importance of water column vs zooplankton variables in the determination of late-stage larval fish assemblage structure in coastal waters of a coral reef lagoon

    Directory of Open Access Journals (Sweden)

    Laure Carassou

    2009-10-01

    Full Text Available The relationship between fish larvae and their zooplanktonic prey has not been fully explored for late-stage larvae of coral-reef fish in lagoonal environments. However, compared to most temperate taxa, these larvae are characterized by strong sensory and swimming abilities, which may influence their feeding behaviour in the water column. The present study aims to determine the relative importance of the water column and zooplankton variables for the structure of pre-settlement larval fish assemblages within a single season in three bays of the coral reef lagoon of New Caledonia, southwest Pacific. The structure of larval assemblages was found to be explained better by water column variables in two out of the three bays examined. Zooplankton variables only played a role in one bay out of the three, probably due to the lower variability in the water column variables. Moreover, the relationship between total larval fish abundance and zooplankton density was not significant in any of the three bays. These results suggest that the relationship between late-stage coral-reef fish larvae and their prey: 1 is difficult to detect at small spatial and temporal scales, 2 is probably complex and non-linear, 3 depends on environmental conditions, and 4 probably varies between fish taxa.

  15. Association and relative importance of multiple obesity measures with bone mineral density: the National Health and Nutrition Examination Survey 2005-2006.

    Science.gov (United States)

    Yang, Shuman; Shen, Xuejun

    2015-01-01

    All obesity measures were positively associated with femoral neck bone mineral density (BMD), but not with lumbar spine BMD. Hip circumference was the most important obesity measure in relation to BMD. Multiple measures are used to quantify obesity; different obesity measures have diverse relationship with BMD. Which obesity measure has the most important value in relation to BMD is still poorly understood. We examined the association between multiple obesity measures and BMD and determined the relative importance (RI, percentage of variation) of multiple obesity measures associated with BMD. Data from 5287 men and women aged between 8 and 69 years (mean age = 29 years) in the National Health and Nutrition Examination Survey 2005-2006 were analyzed. Body mass index (BMI), waist circumference, hip circumference, body fat mass (FM) index, total body FM, abdominal FM, and appendicular FM were considered the exposures and femoral neck and lumbar spine BMD the outcomes. In the multivariable analysis, greater BMI and hip circumference were associated with increased BMD at the lumbar spine and femoral neck (all P obesity variables were positively associated with increased femoral neck BMD only (all P obesity measures associated with femoral neck BMD was much greater than that associated with lumbar spine BMD. Moreover, hip circumference had higher RI (19.8 for femoral neck BMD; 7.0 for lumbar spine BMD) than other obesity measures (all RIs ≤14.1 for femoral neck BMD; all RIs ≤3.5 for lumbar spine BMD) in relation to BMD. All obesity measures were positively associated with femoral neck BMD, but not with lumbar spine BMD. Hip circumference was the most important obesity measure in relation to BMD.

  16. Biogenic carbon in combustible waste: Waste composition, variability and measurement uncertainty

    DEFF Research Database (Denmark)

    Larsen, Anna Warberg; Fuglsang, Karsten; Pedersen, Niels H.

    2013-01-01

    described in the literature. This study addressed the variability of biogenic and fossil carbon in combustible waste received at a municipal solid waste incinerator. Two approaches were compared: (1) radiocarbon dating (14C analysis) of carbon dioxide sampled from the flue gas, and (2) mass and energy......, the measurement uncertainties related to the two approaches were determined. Two flue gas sampling campaigns at a full-scale waste incinerator were included: one during normal operation and one with controlled waste input. Estimation of carbon contents in the main waste types received was included. Both the 14C...... method and the balance method represented promising methods able to provide good quality data for the ratio between biogenic and fossil carbon in waste. The relative uncertainty in the individual experiments was 7–10% (95% confidence interval) for the 14C method and slightly lower for the balance method....

  17. Prediction of extubation readiness in extreme preterm infants based on measures of cardiorespiratory variability.

    Science.gov (United States)

    Precup, Doina; Robles-Rubio, Carlos A; Brown, Karen A; Kanbar, L; Kaczmarek, J; Chawla, S; Sant'Anna, G M; Kearney, Robert E

    2012-01-01

    The majority of extreme preterm infants require endotracheal intubation and mechanical ventilation (ETT-MV) during the first days of life to survive. Unfortunately this therapy is associated with adverse clinical outcomes and consequently, it is desirable to remove ETT-MV as quickly as possible. However, about 25% of extubated infants will fail and require re-intubation which is also associated with a 5-fold increase in mortality and a longer stay in the intensive care unit. Therefore, the ultimate goal is to determine the optimal time for extubation that will minimize the duration of MV and maximize the chances of success. This paper presents a new objective predictor to assist clinicians in making this decision. The predictor uses a modern machine learning method (Support Vector Machines) to determine the combination of measures of cardiorespiratory variability, computed automatically, that best predicts extubation readiness. Our results demonstrate that this predictor accurately classified infants who would fail extubation.

  18. Development of a time-variable nuclear pulser for half life measurements

    Energy Technology Data Exchange (ETDEWEB)

    Zahn, Guilherme S.; Domienikan, Claudio; Carvalhaes, Roberto P. M.; Genezini, Frederico A. [Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP. P.O. Box 11049, Sao Paulo, 05422-970 (Brazil)

    2013-05-06

    In this work a time-variable pulser system with an exponentially-decaying pulse frequency is presented, which was developed using the low-cost, open-source Arduino microcontroler plataform. In this system, the microcontroller produces a TTL signal in the selected rate and a pulse shaper board adjusts it to be entered in an amplifier as a conventional pulser signal; both the decay constant and the initial pulse rate can be adjusted using a user-friendly control software, and the pulse amplitude can be adjusted using a potentiometer in the pulse shaper board. The pulser was tested using several combinations of initial pulse rate and decay constant, and the results show that the system is stable and reliable, and is suitable to be used in half-life measurements.

  19. Cortisol Variability and Self-reports in the Measurement of Work-related Stress

    DEFF Research Database (Denmark)

    Karlson, Björn; Eek, Frida; Hansen, Åse Marie

    2011-01-01

    We examined whether a high cortisol awakening response (CAR) and low cortisol decline over the day (CDD) are related to self-reported work stress and well-being, and whether there are gender differences in these relationships. Three hundred eighty-three working men and women responded to a survey...... measuring job stress factors, mastery at work, symptoms and well-being. Salivary cortisol was sampled at awakening, after 45 min and at 21:00, from which the variables CAR and CDD were defi ned. A high CAR was associated with lower perceived job control and work mastery, and poorer well-being. Low CDD...... was associated only with higher job demands, but the self-report scores showed a number of interactions between cortisol group and gender. Among women, those showing a low CDD, compared with those with a higher CDD, had more favourable scores on a number of job stress factors and symptom load. In contrast, among...

  20. Carpet-dust chemicals as measures of exposure: Implications of variability

    Directory of Open Access Journals (Sweden)

    Whitehead Todd P

    2012-03-01

    Full Text Available Abstract Background There is increasing interest in using chemicals measured in carpet dust as indicators of chemical exposures. However, investigators have rarely sampled dust repeatedly from the same households and therefore little is known about the variability of chemical levels that exist within and between households in dust samples. Results We analyzed 9 polycyclic aromatic hydrocarbons, 6 polychlorinated biphenyls, and nicotine in 68 carpet-dust samples from 21 households in agricultural communities of Fresno County, California collected from 2003-2005. Chemical concentrations (ng per g dust ranged from Conclusions Our findings suggest that attenuation bias should be relatively modest when using these semi-volatile carpet-dust chemicals as exposure surrogates in epidemiologic studies.

  1. Variability in automatic activation as an unobtrusive measure of racial attitudes: a bona fide pipeline?

    Science.gov (United States)

    Fazio, R H; Jackson, J R; Dunton, B C; Williams, C J

    1995-12-01

    The research examines an unobtrusive measure of racial attitudes based on the evaluations that are automatically activated from memory on the presentation of Black versus White faces. Study 1, which concerned the technique's validity, obtained different attitude estimates for Black and White participants and also revealed that the variability among White participants was predictive of other race-related judgments and behavior. Study 2 concerned the lack of correspondence between the unobtrusive estimates and Modern Racism Scale (MRS) scores. The reactivity of the MRS was demonstrated in Study 3. Study 4 observed an interaction between the unobtrusive estimates and an individual difference in motivation to control prejudiced reactions when predicting MRS scores. The theoretical implications of the findings for consideration of automatic and controlled components of racial prejudice are discussed, as is the status of the MRS.

  2. Gas permeation measurement under defined humidity via constant volume/variable pressure method

    KAUST Repository

    Jan Roman, Pauls

    2012-02-01

    Many industrial gas separations in which membrane processes are feasible entail high water vapour contents, as in CO 2-separation from flue gas in carbon capture and storage (CCS), or in biogas/natural gas processing. Studying the effect of water vapour on gas permeability through polymeric membranes is essential for materials design and optimization of these membrane applications. In particular, for amine-based CO 2 selective facilitated transport membranes, water vapour is necessary for carrier-complex formation (Matsuyama et al., 1996; Deng and Hägg, 2010; Liu et al., 2008; Shishatskiy et al., 2010) [1-4]. But also conventional polymeric membrane materials can vary their permeation behaviour due to water-induced swelling (Potreck, 2009) [5]. Here we describe a simple approach to gas permeability measurement in the presence of water vapour, in the form of a modified constant volume/variable pressure method (pressure increase method). © 2011 Elsevier B.V.

  3. Driving Extreme Variability: Measuring the Changing Characteristics of the X-ray Emitting Coronae in AGN

    Science.gov (United States)

    Wilkins, Daniel; Gallo, Luigi C.; Kara, Erin; Fabian, Andrew c

    2014-08-01

    Through detailed analysis of the reflection of the X-ray continuum from the accretion disc, it is possible to probe the innermost structures right down to the innermost stable circular orbit and event horizon around the supermassive black holes in AGN. By measuring the emissivity profile of the accretion disc, that is its pattern of illumination by the coronal X-ray source, along with reverberation time lags between variability in the X-ray continuum and reflection, it has proven possible to measure the geometry and spatial extend of the corona that produces the X-ray continuum when the observed data are combined with insight gained from general relativistic ray tracing simulations.We conducted detailed analysis of both the X-ray continuum and its reflection from the accretion disc during periods of high and low X-ray flux drawn from long observations of the narrow line Seyfert 1 galaxy, 1H0707-495, totalling more than 1.3Ms with XMM Newton, as well as during the course of an X-ray flare in another narrow line Seyfert 1 galaxy, Markarian 335, observed in 2013 by Suzaku.These observations allow us to trace, for the first time, from observations, the evolution of the X-ray emitting corona that gives rise to the extreme variability seen in the X-ray emission from AGN. We detect expansion in the corona as well as variations in its energetics as the X-ray flux increases, which gives us insight into the physical processes by which energy is liberated from black hole accretion flows and allows observational constraints to be placed upon theoretical models of black hole accretion flows and associated coronae.

  4. Discrimination between monomorphic and polymorphic ventricular tachycardia using cycle length variability measured by wavelet transform analysis.

    Science.gov (United States)

    Sierra, G; Gómez, M J; Le Guyader, P; Trelles, F; Cardinal, R; Savard, P; Nadeau, R

    1998-07-01

    normalized standard deviation of the intervals between individual electrograms (0.076 +/- 0.006). No significant differences were shown (P = .0022), and a strong linear correlation was found between both measurements (Pearson correlation coefficient, .966). It is concluded that WT analysis discriminated accurately between MVT and PVT, and a quantitative relation was found with the spatial dispersion of sites of earliest epicardial activation. The WT results strongly correlated with those obtained by another method of estimating cycle length variability. Methodologically, the strength of the WT lies in the complementary information that could be extracted from the processing of electrograms to enhance the detection/discrimination of different types of arrhythmias.

  5. Lack of Agreement Between Gas Exchange Variables Measured by Two Metabolic Systems

    Science.gov (United States)

    Jakovljevic, Djordje G.; Nunan, David; Donovan, Gay; Hodges, Lynette D.; Sandercock, Gavin R. H.; Brodie, David A.

    2008-01-01

    The purpose of this study was to assess the agreement and consistency between gas exchange variables measured by two online metabolic systems during an incremental exercise test. After obtaining local ethics approval and informed consent, 15 healthy subjects performed an incremental exercise test to volitional fatigue using the Bruce protocol. The Innocor (Innovision, Denmark) and CardiO2 (Medical Graphics, USA) systems were placed in series, with the Innocor mouthpiece attached to the pneumotach of the CardiO2. Metabolic data were analysed during the last 30 seconds of each stage and at peak exercise. There were non- significant differences (p > 0.05) between the two systems in estimation of oxygen consumption (VO2) and in minute ventilation (VE). Mean Cronbach’s alpha for VO2 and VE were 0.88 and 0.92. The Bland-Altman analysis revealed that limits of agreement were -0.52 to 0.55 l.min-1 for VO2, and -8.74 to 10.66 l.min-1 for VE. Carbon dioxide production (VCO2) and consequently respiratory exchange ratio (RER) measured by the Innocor were significantly lower (p < 0.05) through all stages. The CardiO2 measured fraction of expired carbon dioxide (FeCO2) significantly higher (p < 0.05). The limits of agreement for VO2 and VE are wide and unacceptable in cardio-pulmonary exercise testing. The Innocor reported VCO2 systematically lower. Therefore the Innocor and CardiO2 metabolic systems cannot be used interchangeably without affecting the diagnosis of an individual patient. Results from the present study support previous suggestion that considerable care is needed when comparing metabolic data obtained from different automated metabolic systems. Key pointsThere is general concern regarding the limited knowledge available about the accuracy of a number of commercially available systems.Demonstrated limits of agreement between key gas exchange variables (oxygen consumption and minute ventilation) as measured by the two metabolic systems were wide and unacceptable

  6. Importance of measuring non-HDL cholesterol in type 2 diabetes patients.

    Science.gov (United States)

    Ram, Nanik; Ahmed, Bilal; Hashmi, Fauzan; Jabbar, Abdul

    2014-02-01

    To study the correlation between Non-high-density lipoprotein and low-density lipoprotein cholesterol in patients with Type 2 diabetes mellitus and the proportion of patients achieving Adult Treatment Panel III recommended goals. The cross sectional study was conducted at the Diabetic Clinic, Aga Khan University Hospital, Karachi. Data of Type 2 diabetes mellitus patients who attended the clinic bewteen 2007 and 2011 was reviewed. All Type 2 diabetic patients of either gender with fasting lipid profile irrespective of taking lipid lowering therapy were included.Type-1 DM, gestational diabetes, type 2 diabetes patients with pregnancy and those with incomplete data were excluded. Correlation between the low-density lipoprotein and Non-high-density lipoprotein was assessed by applying Cramer V and phi. Proportion of patients achieving Adult Treatment Panel III recommended goals was checked. Multivariable regression was done to identify common factors associated with elevated Non-high-density lipoprotein cholesterol. A total of 1352 patients fulfilling the eligibility criteria were included in the study. Mean age of the patients was 54.5 +/- 11.3 years; 797 (59%) were males; 1122 (83%) had Body Mass Index above 25; and 1016 (75%) had HbA1c > or = 7%. Mean Non-high-density lipoprotein cholesterol was 129 +/- 42 mg/dl. Mean low-density lipoprotein cholesterol was 100 +/- 37 mg/dl. Both low-density lipoprotein important to note that although 728 (53.8%) patients achieved target LDL cholesterol of 130 mg/dl (p 100 mg/dl was independently associated with having Non-high-density lipoprotein cholesterol > 130 mg/dl (Adjusted Odds Ratio 38.6; 95% Confidance Interval = 28.1-53.1). Similarly, age 130 mg/dl (Adjusted Odds Ratio 1.6; 95% Confidance Interval = 1.01 - 2.3). Whereas having obesity Body Mass Index > 25 was 3.6 times more associated to have Non-high-density lipoprotein > 130 mg/dl (Adjusted Odds Ratio 3.6; 95% Confidance Interval = 1.6-7.7). In patients with coronary

  7. Important aspects of end-of-life care among veterans: implications for measurement and quality improvement.

    Science.gov (United States)

    Casarett, David; Pickard, Amy; Amos Bailey, F; Ritchie, Christine; Furman, Christian; Rosenfeld, Ken; Shreve, Scott; Shea, Judy A

    2008-02-01

    To identify aspects of end-of-life care in the U.S. Department of Veterans Affairs (VA) health care system that are not assessed by existing survey instruments and to identify issues that may be unique to veterans, telephone interviews using open-ended questions were conducted with family members of veterans who had received care from a VA facility in the last month of life. Responses were compared to validated end-of-life care assessment instruments in common use. The study took place in four VA medical centers and one family member per patient was invited to participate, selected from medical records using predefined eligibility criteria. These family members were asked to describe positive and negative aspects of the care the veteran received in the last month of life. Interview questions elicited perceptions of care both at VA sites and at non-VA sites. Family reports were coded and compared with items in five existing prospective and retrospective instruments that assess the quality of care that patients receive near the end of life. Interviews were completed with 66 family members and revealed 384 codes describing both positive and negative aspects of care during the last month of life. Almost half of these codes were not represented in any of the five reference instruments (n=174; 45%). These codes, some of which are unique to the veteran population, were grouped into eight categories: information about VA benefits (n=36; 55%), inpatient care (n=36; 55%), access to care (n=33; 50%), transitions in care (n=32; 48%), care that the veteran received at the time of death (n=31; 47%), home care (n=26; 40%), health care facilities (n=12; 18%), and mistakes and complications (n=18; 27%). Although most of the reference instruments assessed some aspect of these categories, they did not fully capture the experiences described by our respondents. These data suggest that many aspects of veterans' end-of-life care that are important to their families are not assessed by

  8. The importance of additionality in evaluating the economic viability of motor-related energy efficiency measures

    OpenAIRE

    Zuberi, Muhammad Jibran Shahzad; Patel, Martin Kumar

    2017-01-01

    The additionality of an energy efficiency (EE) measure is defined as the supplementary impact of a measure beyond standard practices and autonomous changes. The consideration of additionality and the manner of accounting for it may strongly influence the cost-effectiveness of the EE measures and consequently the decision by policy makers. Many studies on energy efficiency improvement potentials fail to provide transparency regarding the methodology and underlying data (discount rate, lifetime...

  9. Measuring FMD in the brachial artery: how important is QRS gating?

    Science.gov (United States)

    Kizhakekuttu, Tinoy J; Gutterman, David D; Phillips, Shane A; Jurva, Jason W; Arthur, Emily I L; Das, Emon; Widlansky, Michael E

    2010-10-01

    Recommendations for the measurement of brachial flow-mediated dilation (FMD) typically suggest images be obtained at identical times in the cardiac cycle, usually end diastole (QRS complex onset). This recommendation presumes that inter-individual differences in arterial compliance are minimized. However, published evidence is conflicting. Furthermore, ECG gating is not available on many ultrasound systems; it requires an expensive software upgrade or increased image processing time. We tested whether analysis of images acquired with QRS gating or with the more simplified method of image averaging would yield similar results. We analyzed FMD and nitroglycerin-mediated dilation (NMD) in 29 adults with type 2 diabetes mellitus and in 31 older adults and 12 young adults without diabetes, yielding a range of brachial artery distensibility. FMD and NMD were measured using recommended QRS-gated brachial artery diameter measurements and, alternatively, the average brachial diameters over the entire R-R interval. We found strong agreement between both methods for FMD and NMD (intraclass correlation coefficients = 0.88-0.99). Measuring FMD and NMD using average diameter measurements significantly reduced post-image-processing time (658.9 ± 71.6 vs. 1,024.1 ± 167.6 s for QRS-gated analysis, P FMD and NMD measurements based on average diameter measurements can be performed without reducing accuracy. This finding may allow for simplification of FMD measurement and aid in the development of FMD as a potentially useful clinical tool.

  10. Assessing variability in audiovisual speech integration skills using capacity and accuracy measures.

    Science.gov (United States)

    Altieri, Nicholas; Hudock, Daniel

    2014-10-01

    While most normal-hearing listeners rely on the auditory modality to obtain speech information, research has demonstrated the importance that non-auditory modalities have on language recognition during face-to-face communication. The efficient utilization of the visual modality becomes increasingly important in difficult listening conditions, and especially for older and hearing-impaired listeners with sensory or cognitive decline. First, this report will quantify audiovisual integration skills using a recently developed capacity measure that incorporates speed and accuracy. Second, to investigate sensory factors contributing to integration ability, high and low-frequency hearing thresholds will be correlated with capacity, as well as gain measures from sentence recognition. Integration scores were obtained from a within-subjects design using an open-set sentence speech recognition experiment and a closed set speeded-word classification experiment, designed to examine integration (i.e. capacity). A sample of 44 adult listeners without a self-reported history of hearing-loss was recruited. RESULTS demonstrated a significant relationship between measures of audiovisual integration and hearing thresholds. Our data indicated that a listener's ability to integrate auditory and visual speech information in the domains of speed and accuracy is associated with auditory sensory capabilities and possibly other sensory and cognitive factors.

  11. Body mass index is related to autonomic nervous system activity as measured by heart rate variability.

    Science.gov (United States)

    Molfino, A; Fiorentini, A; Tubani, L; Martuscelli, M; Rossi Fanelli, F; Laviano, A

    2009-10-01

    Autonomic nervous system activity is involved in body weight regulation. We assessed whether the body mass index (BMI) is related to the autonomic nervous system activity as assessed by heart rate variability (HRV). Twenty-five adult normotensive, euglycemic healthy males (M) and females (F) were studied (M/F=13/12). BMI was assessed in each individual. HRV was assessed and the domains of low frequencies (LF, index of the sympathetic modulation) and high frequencies (HF, index of the parasympathetic modulation) were measured. Data were statistically analyzed and are presented as mean+/-s.d. Mean BMI did not correlate with either HF or LF. It inversely related to HF (r=-0.50, P<0.01), whereas its relationship with LF was marginally significant (r=-0.39, P=0.05). The HF in individuals with BMI <20 kg/m(2) was significantly higher from those measured in the remaining subjects (P<0.05). The results support the role of parasympathetic activity in influencing BMI through likely modulation of body weight.

  12. Measuring stress level of dairy cows during milking using by geometric indices of heart rate variability

    Directory of Open Access Journals (Sweden)

    Levente Kovács

    2013-05-01

    Heart rate (HR and heart rate variability (HRV were investigated in cows (n=32, age: 3.86 years, milk production: 35±2.5 kg, DIM: 150±15 milked in a parallel milking parlour. Geometric parameters of HRV (SD1 and SD2 were calculated using Poincare graphs. HRV indices of resting 1 h after midday milking (reference period were compared to those measured during the different phases of the evening milking (driving; in the holding pen; udder preparation; milking; after milking in the milking stall. There was no difference between the reference period and the different phases of milking in animal welfare terms. During the reference period SD2 (198.5 ms was significantly higher (p<0.05 than every other measured period suggesting an increasing parasympathetic tone after milking. This parasympathetic predominance decreased with time of the day (1.5 h after milking. SD2 was significantly affected by parity, by the breeding bull (p<0.01 and by milk production (p<0.05. SD2 was notably higher (102.8 ms in multiparous cows than in primiparous cows (p<0.017; α=0.005 during resting and milking. Results suggested that a conventional milking process is not really stressful for cows. Primiparous cows were more susceptible of milking process than multiparous ones. SD2 is a good marker of vagus activity and affected by several independent factors.

  13. Selection of entropy-measure parameters for knowledge discovery in heart rate variability data.

    Science.gov (United States)

    Mayer, Christopher C; Bachler, Martin; Hörtenhuber, Matthias; Stocker, Christof; Holzinger, Andreas; Wassertheurer, Siegfried

    2014-01-01

    Heart rate variability is the variation of the time interval between consecutive heartbeats. Entropy is a commonly used tool to describe the regularity of data sets. Entropy functions are defined using multiple parameters, the selection of which is controversial and depends on the intended purpose. This study describes the results of tests conducted to support parameter selection, towards the goal of enabling further biomarker discovery. This study deals with approximate, sample, fuzzy, and fuzzy measure entropies. All data were obtained from PhysioNet, a free-access, on-line archive of physiological signals, and represent various medical conditions. Five tests were defined and conducted to examine the influence of: varying the threshold value r (as multiples of the sample standard deviation σ, or the entropy-maximizing rChon), the data length N, the weighting factors n for fuzzy and fuzzy measure entropies, and the thresholds rF and rL for fuzzy measure entropy. The results were tested for normality using Lilliefors' composite goodness-of-fit test. Consequently, the p-value was calculated with either a two sample t-test or a Wilcoxon rank sum test. The first test shows a cross-over of entropy values with regard to a change of r. Thus, a clear statement that a higher entropy corresponds to a high irregularity is not possible, but is rather an indicator of differences in regularity. N should be at least 200 data points for r = 0.2 σ and should even exceed a length of 1000 for r = rChon. The results for the weighting parameters n for the fuzzy membership function show different behavior when coupled with different r values, therefore the weighting parameters have been chosen independently for the different threshold values. The tests concerning rF and rL showed that there is no optimal choice, but r = rF = rL is reasonable with r = rChon or r = 0.2σ. Some of the tests showed a dependency of the test significance on the data at hand. Nevertheless, as the medical

  14. Variabilidade na mensuração das medidas orofaciais Variability of orofacial measures

    Directory of Open Access Journals (Sweden)

    Fernanda Veloso Rodrigues

    2008-01-01

    Full Text Available OBJETIVO: Verificar o grau da variabilidade das medidas orofaciais, entre fonoaudiólogos especialistas em Motricidade Orofacial. MÉTODOS: Estudo longitudinal prospectivo, tendo 30 fonoaudiólogos especialistas em Motricidade Orofacial realizado, em dois momentos distintos, com uso de paquímetro digital, a mensuração de dez medidas orofaciais de um sujeito padrão. Foram comparados os dados inter e intra-examinador por meio das medidas de tendência central, das medidas de dispersão e de testes de hipóteses, com nível de significância de 5%. RESULTADOS: Nove dos dez parâmetros investigados foram considerados como homogêneos na avaliação inter e intra-observadores. A abertura máxima da boca com língua na papila apresentou coeficientes de variação altos, indicando dados heterogêneos, apesar dos valores de correlação inter-observadores terem sido considerados semelhantes. Já na avaliação intra-examinador para este parâmetro foi evidenciada uma diferença significante (p=0,0384. Na análise dos dados, observou-se ainda diferenças próximas ao ponto de corte estabelecido no estudo, na mensuração intra-observador do terço médio da face (p=0,0711 e da abertura máxima da boca (p=0,0677. Dentre as dez variáveis analisadas, não foi observada diminuição do coeficiente de variação da 1ª para 2ª mensuração apenas nos parâmetros terço médio da face e lábio superior. CONCLUSÃO: Não foi observada variabilidade nas mensurações orofaciais realizadas, exceto para o parâmetro abertura m��xima da boca com língua na papila, indicando que dados produzidos por diferentes profissionais podem ser considerados parcialmente confiáveis.PURPOSE: To verify the degree of variability of orofacial measures, among speech pathologists who are specialists in orofacial myology. METHODS: A prospective study was carried out, where 30 speech pathologists who are specialists in orofacial myology measured, in two different moments

  15. Input variable selection for data-driven models of Coriolis flowmeters for two-phase flow measurement

    Science.gov (United States)

    Wang, Lijuan; Yan, Yong; Wang, Xue; Wang, Tao

    2017-03-01

    Input variable selection is an essential step in the development of data-driven models for environmental, biological and industrial applications. Through input variable selection to eliminate the irrelevant or redundant variables, a suitable subset of variables is identified as the input of a model. Meanwhile, through input variable selection the complexity of the model structure is simplified and the computational efficiency is improved. This paper describes the procedures of the input variable selection for the data-driven models for the measurement of liquid mass flowrate and gas volume fraction under two-phase flow conditions using Coriolis flowmeters. Three advanced input variable selection methods, including partial mutual information (PMI), genetic algorithm-artificial neural network (GA-ANN) and tree-based iterative input selection (IIS) are applied in this study. Typical data-driven models incorporating support vector machine (SVM) are established individually based on the input candidates resulting from the selection methods. The validity of the selection outcomes is assessed through an output performance comparison of the SVM based data-driven models and sensitivity analysis. The validation and analysis results suggest that the input variables selected from the PMI algorithm provide more effective information for the models to measure liquid mass flowrate while the IIS algorithm provides a fewer but more effective variables for the models to predict gas volume fraction.

  16. VALIDITY OF SINGLE VARIABLES AND COMPOSITE INDEXES FOR MEASURING DISEASE-ACTIVITY IN RHEUMATOID-ARTHRITIS

    NARCIS (Netherlands)

    VANDERHEIJDE, DMFM; VANTHOF, MA; VANRIEL, PLCM; VANLEEUWEN, MA; VANRIJSWIJK, MH; VANDEPUTTE, LBA

    There is no agreement as to which variable best mirrors disease activity in rheumatoid arthritis (RA) and no studies have been performed on the validity of disease activity variables. In this study the validity of 10 commonly used single variables and three composite indices was tested. All patients

  17. Measuring the effect of inter-study variability on estimating prediction error.

    Directory of Open Access Journals (Sweden)

    Shuyi Ma

    Full Text Available The biomarker discovery field is replete with molecular signatures that have not translated into the clinic despite ostensibly promising performance in predicting disease phenotypes. One widely cited reason is lack of classification consistency, largely due to failure to maintain performance from study to study. This failure is widely attributed to variability in data collected for the same phenotype among disparate studies, due to technical factors unrelated to phenotypes (e.g., laboratory settings resulting in "batch-effects" and non-phenotype-associated biological variation in the underlying populations. These sources of variability persist in new data collection technologies.Here we quantify the impact of these combined "study-effects" on a disease signature's predictive performance by comparing two types of validation methods: ordinary randomized cross-validation (RCV, which extracts random subsets of samples for testing, and inter-study validation (ISV, which excludes an entire study for testing. Whereas RCV hardwires an assumption of training and testing on identically distributed data, this key property is lost in ISV, yielding systematic decreases in performance estimates relative to RCV. Measuring the RCV-ISV difference as a function of number of studies quantifies influence of study-effects on performance.As a case study, we gathered publicly available gene expression data from 1,470 microarray samples of 6 lung phenotypes from 26 independent experimental studies and 769 RNA-seq samples of 2 lung phenotypes from 4 independent studies. We find that the RCV-ISV performance discrepancy is greater in phenotypes with few studies, and that the ISV performance converges toward RCV performance as data from additional studies are incorporated into classification.We show that by examining how fast ISV performance approaches RCV as the number of studies is increased, one can estimate when "sufficient" diversity has been achieved for learning a

  18. A novel variable baseline visibility detection system and its measurement method

    Science.gov (United States)

    Li, Meng; Jiang, Li-hui; Xiong, Xing-long; Zhang, Guizhong; Yao, JianQuan

    2017-10-01

    As an important meteorological observation instrument, the visibility meter can ensure the safety of traffic operation. However, due to the optical system contamination as well as sample error, the accuracy and stability of the equipment are difficult to meet the requirement in the low-visibility environment. To settle this matter, a novel measurement equipment was designed based upon multiple baseline, which essentially acts as an atmospheric transmission meter with movable optical receiver, applying weighted least square method to process signal. Theoretical analysis and experiments in real atmosphere environment support this technique.

  19. LACK OF AGREEMENT BETWEEN GAS EXCHANGE VARIABLES MEASURED BY TWO METABOLIC SYSTEMS

    Directory of Open Access Journals (Sweden)

    DjordjeG. Jakovljevic

    2008-03-01

    Full Text Available The purpose of this study was to assess the agreement and consistency between gas exchange variables measured by two online metabolic systems during an incremental exercise test. After obtaining local ethics approval and informed consent, 15 healthy subjects performed an incremental exercise test to volitional fatigue using the Bruce protocol. The Innocor (Innovision, Denmark and CardiO2 (Medical Graphics, USA systems were placed in series, with the Innocor mouthpiece attached to the pneumotach of the CardiO2. Metabolic data were analysed during the last 30 seconds of each stage and at peak exercise. There were non- significant differences (p > 0.05 between the two systems in estimation of oxygen consumption (VO2 and in minute ventilation (VE. Mean Cronbach's alpha for VO2 and VE were 0.88 and 0.92. The Bland-Altman analysis revealed that limits of agreement were -0.52 to 0.55 l.min-1 for VO2, and -8.74 to 10.66 l.min-1 for VE. Carbon dioxide production (VCO2 and consequently respiratory exchange ratio (RER measured by the Innocor were significantly lower (p < 0.05 through all stages. The CardiO2 measured fraction of expired carbon dioxide (FeCO2 significantly higher (p < 0.05. The limits of agreement for VO2 and VE are wide and unacceptable in cardio-pulmonary exercise testing. The Innocor reported VCO2 systematically lower. Therefore the Innocor and CardiO2 metabolic systems cannot be used interchangeably without affecting the diagnosis of an individual patient. Results from the present study support previous suggestion that considerable care is needed when comparing metabolic data obtained from different automated metabolic systems.

  20. Non-Proliferation, the IAEA Safeguards System, and the importance of nuclear material measurements

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, Rebecca S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-18

    The objective of this project is to explain the contribution of nuclear material measurements to the system of international verification of State declarations and the non-proliferation of nuclear weapons.

  1. Measuring the relative importance of strategic thinking dimensions in relation to counterproductive behavior

    Directory of Open Access Journals (Sweden)

    Afsaneh Zamani Moghaddam

    2013-11-01

    Full Text Available The purpose of this paper is to explore the relative importance of strategic thinking dimensions in prediction of counter-productive behavior. The research method is based on a descriptive- Survey research. After collecting the questionnaires from 73 top managers and 110 staffs, the correlations between strategic thinking dimensions and counterproductive behavior were calculated. The relative importance method was used to calculate the relative weight of each dimension of strategic thinking in prediction of counterproductive behaviors. The results show that the strategic thinking of top managers is associated with their counterproductive behavior (correlation coefficient -0.38. Furthermore, The results of the Relative Importance Method indicate that the relative importance of each dimension of strategic thinking in prediction of counterproductive behavior is not the same. System perspective with 31.1% has the highest importance and hypothesis driven with 11.7% has the lowest weight. Intent focus, thinking in time and intelligent opportunism predict 14.1%, 13.3%, and 29.8% of counter-productive changes, respectively.

  2. Validity of (Ultra-Short Recordings for Heart Rate Variability Measurements.

    Directory of Open Access Journals (Sweden)

    M Loretto Munoz

    Full Text Available In order to investigate the applicability of routine 10s electrocardiogram (ECG recordings for time-domain heart rate variability (HRV calculation we explored to what extent these (ultra-short recordings capture the "actual" HRV.The standard deviation of normal-to-normal intervals (SDNN and the root mean square of successive differences (RMSSD were measured in 3,387 adults. SDNN and RMSSD were assessed from (ultrashort recordings of 10s(3x, 30s, and 120s and compared to 240s-300s (gold standard measurements. Pearson's correlation coefficients (r, Bland-Altman 95% limits of agreement and Cohen's d statistics were used as agreement analysis techniques.Agreement between the separate 10s recordings and the 240s-300s recording was already substantial (r = 0.758-0.764/Bias = 0.398-0.416/d = 0.855-0.894 for SDNN; r = 0.853-0.862/Bias = 0.079-0.096/d = 0.150-0.171 for RMSSD, and improved further when three 10s periods were averaged (r = 0.863/Bias = 0.406/d = 0.874 for SDNN; r = 0.941/Bias = 0.088/d = 0.167 for RMSSD. Agreement increased with recording length and reached near perfect agreement at 120s (r = 0.956/Bias = 0.064/d = 0.137 for SDNN; r = 0.986/Bias = 0.014/d = 0.027 for RMSSD. For all recording lengths and agreement measures, RMSSD outperformed SDNN.Our results confirm that it is unnecessary to use recordings longer than 120s to obtain accurate measures of RMSSD and SDNN in the time domain. Even a single 10s (standard ECG recording yields a valid RMSSD measurement, although an average over multiple 10s ECGs is preferable. For SDNN we would recommend either 30s or multiple 10s ECGs. Future research projects using time-domain HRV parameters, e.g. genetic epidemiological studies, could calculate HRV from (ultra-short ECGs enabling such projects to be performed at a large scale.

  3. [Comparison of self-reported anthropometric variables and real measurement data].

    Science.gov (United States)

    Díaz-García, J; González-Zapata, L I; Estrada-Restrepo, A

    2012-06-01

    The objectives of this study were to evaluate self-reporting of weight, height, and waist circumference, and to compare that perception with the real measurements in college students of the MESPYN cohort--Medellin, Salud Pública y Nutrición--from the University of Antioquia (UdeA), Colombia. A cross-sectional study was conducted starting with the first measurement of the MESPYN Cohort 2009-2010. The sample included volunteer students from different academic areas. Self-perception of weight, height, and waist circumference were recorded before the real measurements were performed. Intraclass correlation coefficients (ICC) were calculated for all the variables, and an alpha of 0.05 was used. The concordance between real measurements and self-referred values was evaluated with the Bland and Altman method. 424 volunteer students were included. The average real weight (kg) in males was 67.4 +/- 10.4 and self-reported: 67.0 +/- 11.0; in females the real value was 55.7 +/- 10.1 and self-reported: 55.0 +/- 9.0. The average real height (m) in males was 1.73 +/- 6.1 and self-reported: 1.73 +/- 6.0; in females the real value was 1.60 +/- 5.9 and self-reported: 1.61 +/- 6.0. In males, the average real waist circumference (cm) was 76.6 +/- 8.0 and self-reported: 75.0 +/- 14.0; in females the real value was 69.9 +/- 8.0 and self-reported: 70.0 +/- 9.0. Weight ICC: 0.956, 95% CI (0.95; 0.97), (p < 0.01); height ICC: 0.953, 95%IC (0.91; 0.97), (p < 0.01), and waist circumference ICC: 0.593, 95% IC (0.55; 0.65), (p < 0.01). In conclusion, anthropometric nutritional evaluation of UdeA students can be performed with self-reported data for weight and height, but the evaluation of abdominal obesity requires direct measurement of waist circumference.

  4. United Kingdom windspeed: Measurement, climatology, predictability and link to tropical Atlantic variability

    Science.gov (United States)

    George, Steven Edward

    Windspeed impacts the business performance of many industries yet has received relatively little attention compared with other meteorological fields. The present study addresses this inconsistency. A UK seasonal windspeed climatology is de veloped using a new dataset of United Kingdom hourly windspeed measurements comprising 30 years of observations from 52 geographically dispersed sites. The data are shown to contain significant errors associated with non-ideal measurement conditions. A correction algorithm is described and on application the adjusted site-records exhibit improved homogeneity. Seasonal climatological windspeed char acteristics are modelled using the Weibull distribution: results indicate that central southern England can expect 1-6 near-gale events each winter, compared with 22-27 near-gale events in southwest England. Rare (strong) event return periods are modelled using Gumbell extreme-value theory. Seasonal predictability of winter storminess is investigated using an index defined by the 95th percentile of winter daily maximum windspeed (SI). The interannual variability of SI over Europe is dominated by the North Atlantic Oscillation (NAO, 34% Percentage Variance Ex plained (PVE)). Conversely, a secondary SI mode of variability (SI2, 19% PVE) is seen to have a significant impact over the UK. Multi-field correlation analysis is employed to assess potential SI2 predictability, with statistical forecast models built from the results: the models show mixed skill performance. Tropical North Atlantic (TNA) windspeed is shown to co-vary with winter NAO: surface tradewinds for Dec- Jan-Feb are 19% higher in strong-NAO composite years compared to weak-NAO composite years. In turn this impacts the subsequent distribution of Caribbean rainfall: wet-season precipitation is significantly reduced following a strong winter NAO. It is hypothesised that changes in the TNA trade winds create long lasting SST anomalies, which in turn feedback onto wet season

  5. Predicting Word Reading and Comprehension with Executive Function and Speed Measures Across Development: A Latent Variable Analysis

    Science.gov (United States)

    Christopher, Micaela E.; Miyake, Akira; Keenan, Janice M.; Pennington, Bruce; DeFries, John C.; Wadsworth, Sally J.; Willcutt, Erik; Olson, Richard K.

    2012-01-01

    The present study explored whether different executive control and speed measures (working memory, inhibition, processing speed, and naming speed) independently predict individual differences in word reading and reading comprehension. Although previous studies suggest these cognitive constructs are important for reading, we analyze the constructs simultaneously to test whether each is a unique predictor. We used latent variables from 483 participants (ages 8 to 16) to portion each cognitive and reading construct into its unique and shared variance. In these models we address two specific issues: (a) given that our wide age range may span the theoretical transition from “learning to read” to “reading to learn,” we first test whether the relation between word reading and reading comprehension is stable across two age groups (ages 8 to 10 and 11 to 16); and (b) the main theoretical question of interest: whether what is shared and what is separable for word reading and reading comprehension are associated with individual differences in working memory, inhibition, and measures of processing and naming speed. The results indicated that: (a) the relation between word reading and reading comprehension is largely invariant across the age groups; (b) working memory and general processing speed, but not inhibition or the speeded naming of non-alphanumeric stimuli, are unique predictors of both word reading and comprehension, with working memory equally important for both reading abilities and processing speed more important for word reading. These results have implications for understanding why reading comprehension and word reading are highly correlated yet separable. PMID:22352396

  6. Predicting word reading and comprehension with executive function and speed measures across development: a latent variable analysis.

    Science.gov (United States)

    Christopher, Micaela E; Miyake, Akira; Keenan, Janice M; Pennington, Bruce; DeFries, John C; Wadsworth, Sally J; Willcutt, Erik; Olson, Richard K

    2012-08-01

    The present study explored whether different executive control and speed measures (working memory, inhibition, processing speed, and naming speed) independently predict individual differences in word reading and reading comprehension. Although previous studies suggest these cognitive constructs are important for reading, the authors analyze the constructs simultaneously to test whether each is a unique predictor. Latent variables from 483 participants (ages 8-16 years) were used to portion each cognitive and reading construct into its unique and shared variance. In these models 2 specific issues are addressed: (a) Given that the wide age range may span the theoretical transition from "learning to read" to "reading to learn," the authors first test whether the relation between word reading and reading comprehension is stable across 2 age groups (ages 8-10 and 11-16); and (b) the main theoretical question of interest: whether what is shared and what is separable for word reading and reading comprehension are associated with individual differences in working memory, inhibition, and measures of processing and naming speed. The results indicated that (a) the relation between word reading and reading comprehension is largely invariant across the age groups, and (b) working memory and general processing speed, but not inhibition or the speeded naming of non-alphanumeric stimuli, are unique predictors of both word reading and comprehension, with working memory equally important for both reading abilities and processing speed more important for word reading. These results have implications for understanding why reading comprehension and word reading are highly correlated yet separable . (PsycINFO Database Record (c) 2012 APA, all rights reserved).

  7. Using satellite-based measurements to explore spatiotemporal scales and variability of drivers of new particle formation

    Science.gov (United States)

    Sullivan, R. C.; Crippa, P.; Hallar, A. G.; Clarisse, L.; Whitburn, S.; Van Damme, M.; Leaitch, W. R.; Walker, J. T.; Khlystov, A.; Pryor, S. C.

    2016-10-01

    New particle formation (NPF) can potentially alter regional climate by increasing aerosol particle (hereafter particle) number concentrations and ultimately cloud condensation nuclei. The large scales on which NPF is manifest indicate potential to use satellite-based (inherently spatially averaged) measurements of atmospheric conditions to diagnose the occurrence of NPF and NPF characteristics. We demonstrate the potential for using satellite-based measurements of insolation (UV), trace gas concentrations (sulfur dioxide (SO2), nitrogen dioxide (NO2), ammonia (NH3), formaldehyde (HCHO), and ozone (O3)), aerosol optical properties (aerosol optical depth (AOD) and Ångström exponent (AE)), and a proxy of biogenic volatile organic compound emissions (leaf area index (LAI) and temperature (T)) as predictors for NPF characteristics: formation rates, growth rates, survival probabilities, and ultrafine particle (UFP) concentrations at five locations across North America. NPF at all sites is most frequent in spring, exhibits a one-day autocorrelation, and is associated with low condensational sink (AOD × AE) and HCHO concentrations, and high UV. However, there are important site-to-site variations in NPF frequency and characteristics, and in which of the predictor variables (particularly gas concentrations) significantly contribute to the explanatory power of regression models built to predict those characteristics. This finding may provide a partial explanation for the reported spatial variability in skill of simple generalized nucleation schemes in reproducing observed NPF. In contrast to more simple proxies developed in prior studies (e.g., based on AOD, AE, SO2, and UV), use of additional predictors (NO2, NH3, HCHO, LAI, T, and O3) increases the explained temporal variance of UFP concentrations at all sites.

  8. Relation between the Sensory and Anthropometric Variables in the Quiet Standing Postural Control: Is the Inverted Pendulum Important for the Static Balance Control?

    Science.gov (United States)

    Alonso, Angélica C; Mochizuki, Luis; Silva Luna, Natália Mariana; Ayama, Sérgio; Canonica, Alexandra Carolina; Greve, Júlia M D A

    2015-01-01

    The aim of this study was to evaluate the relation between the sensory and anthropometric variables in the quiet standing. One hundred individuals (50 men, 50 women; 20-40 years old) participated in this study. For all participants, the body composition (fat tissue, lean mass, bone mineral content, and bone mineral density) and body mass, height, trunk-head length, lower limb length, and upper limb length were measured. The center of pressure was measured during the quiet standing posture, the eyes opened and closed with a force platform. Correlation and regression analysis were run to analyze the relation among body composition, anthropometric data, and postural sway. The correlation analysis showed low relation between postural sway and anthropometric variables. The multiple linear regression analyses showed that the height explained 12% of the mediolateral displacement and 11% of the center of pressure area. The length of the trunk head explained 6% of displacement in the anteroposterior postural sway. During eyes closed condition, the support basis and height explained 18% of mediolateral postural sway. The postural control depends on body composition and dimension. This relation is mediated by the sensory information. The height was the anthropometric variable that most influenced the postural sway.

  9. Relation between the Sensory and Anthropometric Variables in the Quiet Standing Postural Control: Is the Inverted Pendulum Important for the Static Balance Control?

    Directory of Open Access Journals (Sweden)

    Angélica C. Alonso

    2015-01-01

    Full Text Available The aim of this study was to evaluate the relation between the sensory and anthropometric variables in the quiet standing. Methods. One hundred individuals (50 men, 50 women; 20–40 years old participated in this study. For all participants, the body composition (fat tissue, lean mass, bone mineral content, and bone mineral density and body mass, height, trunk-head length, lower limb length, and upper limb length were measured. The center of pressure was measured during the quiet standing posture, the eyes opened and closed with a force platform. Correlation and regression analysis were run to analyze the relation among body composition, anthropometric data, and postural sway. Results. The correlation analysis showed low relation between postural sway and anthropometric variables. The multiple linear regression analyses showed that the height explained 12% of the mediolateral displacement and 11% of the center of pressure area. The length of the trunk head explained 6% of displacement in the anteroposterior postural sway. During eyes closed condition, the support basis and height explained 18% of mediolateral postural sway. Conclusion. The postural control depends on body composition and dimension. This relation is mediated by the sensory information. The height was the anthropometric variable that most influenced the postural sway.

  10. Relative and Combined Prognostic Importance of On-Treatment Mean and Visit-to-Visit Blood Pressure Variability in ONTARGET and TRANSCEND Patients.

    Science.gov (United States)

    Mancia, Giuseppe; Schumacher, Helmut; Böhm, Michael; Redon, Josep; Schmieder, Roland E; Verdecchia, Paolo; Sleight, Peter; Teo, Koon; Yusuf, Salim

    2017-11-01

    In 28 790 patients recruited for the ONTARGET (Ongoing Treatment Alone and in Combination With Ramipril Global End Point Trials) and TRANSCEND (Telmisartan Randomized Assessment Study in ACE Intolerant Subjects With Cardiovascular Disease) trials, we investigated the prognostic value for cardiovascular events (primary outcome) of (1)on-treatment visit-to-visit systolic blood pressure (SBP) variability versus mean SBP and (2) the 2 measures together. SBP variability was measured by the coefficient of variation (CV) of mean SBP to which it was unrelated. Confounders such as variable time and number of visits from which to calculate SBP-CV were avoided by using the same number of visits at identical times in all patients. The covariate-adjusted risk of the primary outcome (Cox models) increased as SBP-CV or mean on-treatment quintile SBP increased, but only for mean on-treatment SBP, the relationship achieved statistical significance: global test for trend, P=0.12 versus PURL: http//www.clinicaltrial.gov. Unique identifier: NCT153.101. © 2017 American Heart Association, Inc.

  11. The Importance of Sensory-Motor Control in Providing Core Stability Implications for Measurement and Training

    NARCIS (Netherlands)

    Borghuis, Jan; Hof, At L.; Lemmink, Koen A. P. M.

    2008-01-01

    Although the hip musculature is found to be very important in connecting the core to the lower extremities and in transferring forces from and to the core, it is proposed to leave the hip musculature out of consideration when talking about the concept of core stability. A low level of co-contraction

  12. The metabolic syndrome in long-term cancer survivors, an important target for secondary preventive measures

    NARCIS (Netherlands)

    Nuver, J; Smit, AJ; Postma, A; Sleijfer, DT; Gietema, JA

    With increasing numbers of cancer survivors, attention has been drawn to long-term complications of curative cancer treatment, including a range of metabolic disorders. These metabolic disorders often resemble the components of the so-called metabolic syndrome, or syndrome X, which is an important

  13. Health status measurement in COPD : the minimal clinically important difference of the clinical COPD questionnaire

    NARCIS (Netherlands)

    Kocks, J. W. H.; Tuinenga, M. G.; Uil, S. M.; van den Berg, J. W. K.; Stahl, E.; van der Molen, T.

    2006-01-01

    Background: Patient-reported outcomes ( PRO) questionnaires are being increasingly used in COPD clinical studies. The challenge facing investigators is to determine what change is significant, ie what is the minimal clinically important difference (MCID). This study aimed to identify the MCID for

  14. Measuring Anxiety in Children: The Importance of Separate Mother and Father Reports

    Science.gov (United States)

    Jansen, Mélou; Bodden, Denise H. M.; Muris, Peter; van Doorn, Marleen; Granic, Isabela

    2017-01-01

    Background: Previous research suggests that it is important to use parental reports when assessing children's anxiety, but it remains unclear to what extent there are differences between mothers' and fathers' scores and whether these potential differences have any repercussions for the psychometric properties of the scale being used. Objective:…

  15. Strategic B2B customer experience management: the importance of outcomes-based measures

    OpenAIRE

    Zolkiewski, Judy; Story, Victoria; Burton, Jamie; Chan, Paul; Gomes, Andre; Hunter-Jones, Philippa; O’Malley, Lisa; Peters, Linda D.; Raddats, Chris; Robinson, William

    2017-01-01

    Purpose\\ud \\ud The purpose of this paper is to critique the adequacy of efforts to capture the complexities of customer experience in a business-to-business (B2B) context using input–output measures. The paper introduces a strategic customer experience management framework to capture the complexity of B2B service interactions and discusses the value of outcomes-based measurement.\\ud Design/methodology/approach\\ud \\ud This is a theoretical paper that reviews extant literature related to B2B cu...

  16. Importance of Raman Lidar Aerosol Extinction Measurements for Aerosol-Cloud Interaction Studies

    Directory of Open Access Journals (Sweden)

    Han Zaw

    2016-01-01

    Full Text Available Using a UV Raman Lidar for aerosol extinction, and combining Microwave Radiometer derived Liquid Water Path (LWP with Multifilter Rotating Shadowband Radiometer derived Cloud Optical depth, to get cloud effective radius (Reff, we observe under certain specialized conditions, clear signatures of the Twomey Aerosol Indirect effect on cloud droplet properties which are consistent with the theoretical bounds. We also show that the measurement is very sensitive to how far the aerosol layer is from the cloud base and demonstrate that surface PM25 is far less useful. Measurements from both the DOE ARM site and new results at CCNY are presented.

  17. Measuring efficiency at U.S. banks: accounting for heterogeneity is important

    OpenAIRE

    Loretta J. Mester

    1996-01-01

    Estimates of bank cost efficiency can be biased if bank heterogeneity is ignored. The author compares X-inefficiency measures derived from a model that constrains the cost frontier to be the same for all banks in the nation and a model that allows the cost functions and error terms to differ across Federal Reserve Districts. The author finds that the data reject the single cost function model; X-inefficiency measures based on the single cost function model are, on average, higher than those b...

  18. SATELLITE-MEASURED SPATIAL AND TEMPORAL CHLOROPHYLL-A VARIABILITY IN THE GULF OF TOMINI, SULAWESI

    Directory of Open Access Journals (Sweden)

    I Nyoman Radiarta

    2009-12-01

    Full Text Available Chlorophyll-a concentration, an index of phytoplankton biomass, is an important parameter for fisheries resources and marine aquaculture development. Spatial and temporal variability of surface cholophyll-a (chl-a concentration and water condition in the Gulf of Tomini were investigated using monthly climatologies the Sea-viewing Wide Field-of-view sensor (SeaWiFS, sea surface temperature (SST, and wind data from January 2000 to December 2007. The results showed seasonal variation of chla and SST in the Gulf of Tomini. High chl-a concentrations located in the eastern part of the gulf were observed during the southeast monsoon in August. During the northwest monsoon, chl-a concentrations were relatively low ( 28oC during the northwest monsoon, but low during the southeast monsoon. High wind speed was coincided with high chl-a concentrations. Local forcing such as sea surface heating and wind condition are the mechanisms that controlled the spatial and temporal variations of chlorophyll concentrations.

  19. Ground-based measurements of spatial and temporal variability of snow accumulation in East Antarctica

    Science.gov (United States)

    Eisen, Olaf; Frezzotti, Massimo; Genthon, Christophe; Isaksson, Elisabeth; Magand, Olivier; van den Broeke, Michiel R.; Dixon, Daniel A.; Ekaykin, Alexey; Holmlund, Per; Kameda, Takao; KarlöF, Lars; Kaspari, Susan; Lipenkov, Vladimir Y.; Oerter, Hans; Takahashi, Shuhei; Vaughan, David G.

    2008-06-01

    The East Antarctic Ice Sheet is the largest, highest, coldest, driest, and windiest ice sheet on Earth. Understanding of the surface mass balance (SMB) of Antarctica is necessary to determine the present state of the ice sheet, to make predictions of its potential contribution to sea level rise, and to determine its past history for paleoclimatic reconstructions. However, SMB values are poorly known because of logistic constraints in extreme polar environments, and they represent one of the biggest challenges of Antarctic science. Snow accumulation is the most important parameter for the SMB of ice sheets. SMB varies on a number of scales, from small-scale features (sastrugi) to ice-sheet-scale SMB patterns determined mainly by temperature, elevation, distance from the coast, and wind-driven processes. In situ measurements of SMB are performed at single points by stakes, ultrasonic sounders, snow pits, and firn and ice cores and laterally by continuous measurements using ground-penetrating radar. SMB for large regions can only be achieved practically by using remote sensing and/or numerical climate modeling. However, these techniques rely on ground truthing to improve the resolution and accuracy. The separation of spatial and temporal variations of SMB in transient regimes is necessary for accurate interpretation of ice core records. In this review we provide an overview of the various measurement techniques, related difficulties, and limitations of data interpretation; describe spatial characteristics of East Antarctic SMB and issues related to the spatial and temporal representativity of measurements; and provide recommendations on how to perform in situ measurements.

  20. Reexamining age, race, site, and thermometer type as variables affecting temperature measurement in adults – A comparison study

    Directory of Open Access Journals (Sweden)

    Smith Linda S

    2003-06-01

    Full Text Available Abstract Background As a result of the recent international vigilance regarding disease assessment, accurate measurement of body temperature has become increasingly important. Yet, trusted low-tech, portable mercury glass thermometers are no longer available. Thus, comparing accuracy of mercury-free thermometers with mercury devices is essential. Study purposes were 1 to examine age, race, site as variables affecting temperature measurement in adults, and 2 to compare clinical accuracy of low-tech Galinstan-in-glass device to mercury-in-glass at oral, axillary, groin, and rectal sites in adults. Methods Setting 176 bed accredited healthcare facility, rural northwest US Participants Convenience sample (N = 120 of hospitalized persons ≥ 18 years old. Instruments Temperatures (°F measured at oral, skin (simultaneous, immediately followed by rectal sites with four each mercury-glass (BD and Galinstan-glass (Geratherm thermometers; 10 minute dwell times. Results Participants averaged 61.6 years (SD 17.9, 188 pounds (SD 55.3; 61% female; race: 85% White, 8.3% Native Am., 4.2% Hispanic, 1.7 % Asian, 0.8% Black. For both mercury and Galinstan-glass thermometers, within-subject temperature readings were highest rectally; followed by oral, then skin sites. Galinstan assessments demonstrated rectal sites 0.91°F > oral and ≅ 1.3°F > skin sites. Devices strongly correlated between and across sites. Site difference scores between devices showed greatest variability at skin sites; least at rectal site. 95% confidence intervals of difference scores by site (°F: oral (0.142 – 0.265, axilla (0.167 – 0.339, groin (0.037 – 0.321, and rectal (-0.111 – 0.111. Race correlated with age, temperature readings each site and device. Conclusion Temperature readings varied by age, race. Mercury readings correlated with Galinstan thermometer readings at all sites. Site mean differences between devices were considered clinically insignificant. Still considered

  1. Importance of accurate measurements in nutrition research: dietary flavonoids as a case study

    Science.gov (United States)

    Accurate measurements of the secondary metabolites in natural products and plant foods are critical to establishing diet/health relationships. There are as many as 50,000 secondary metabolites which may influence human health. Their structural and chemical diversity present a challenge to analytic...

  2. The importance of severity of arthrosis for the reliability of bone mineral density measurement in women.

    Science.gov (United States)

    Hayirlioglu, Alper; Gokaslan, Husnu; Cimsit, Canan; Baysal, Begumhan

    2009-02-01

    The objective of this study is to investigate the effect of the severity of degenerative changes on measurements of A-P lumbar spines BMD values and to determine the reliability of DEXA measurements associated with severity of the disease on A-P lumbar spines BMD values using DEXA. The measurements using DEXA were taken from L2-L4 spines and femoral neck of total 271 female cases. One hundred and ten of them had mild arthrosis (Group 0), and 69 had severe arthrosis (Group 1). Ninety-two cases without arthrosis were chosen as control group (Group 2). The cases with arthrosic changes were grouped according to their degree of severity of arthrosis. The groups were compared two by two and Tukey multiple comparison test was used for the analysis of the difference of the means of the groups. The mean age of cases was 61.79, 61.84, and 60.47, respectively. The average height was 157.26, 155.93, and 15.92 cm while the average weight was 69.21, 70.78, and 71.45 kg, respectively. The mean body mass index (BMI) was 0.00283, 0.00291, and 0.00293, respectively. L2-L4 A-P spinal BMD values were 0.9870, 0.9848, and 1.0836 g/cm(2) while the femoral neck BMD values were 0.7964, 0.8056, and 0.8223 g/cm(2), respectively. There was no statistical significance between study and control groups in terms of age, weight, height, BMI, and BMD values obtained from femoral neck. However, lumbar region BMD values of the cases with severe arthrosis were statistically significantly high when compared with other two groups. The femoral neck measurement is the prominent alternative method in severe arthrosis while taking measurements from lumbar region is still the most appropriate method in cases with mild arthrosis without having giant osteophytes.

  3. Variability of measurements of sweat sodium using the regional absorbent-patch method.

    Science.gov (United States)

    Dziedzic, Christine E; Ross, Megan L; Slater, Gary J; Burke, Louise M

    2014-09-01

    There is interest in including recommendations for the replacement of the sodium lost in sweat in individualized hydration plans for athletes. Although the regional absorbent-patch method provides a practical approach to measuring sweat sodium losses in field conditions, there is a need to understand the variability of estimates associated with this technique. Sweat samples were collected from the forearms, chest, scapula, and thigh of 12 cyclists during 2 standardized cycling time trials in the heat and 2 in temperate conditions. Single measure analysis of sodium concentration was conducted immediately by ion-selective electrodes (ISE). A subset of 30 samples was frozen for reanalysis of sodium concentration using ISE, flame photometry (FP), and conductivity (SC). Sweat samples collected in hot conditions produced higher sweat sodium concentrations than those from the temperate environment (P = .0032). A significant difference (P = .0048) in estimates of sweat sodium concentration was evident when calculated from the forearm average (mean ± 95% CL; 64 ± 12 mmol/L) compared with using a 4-site equation (70 ± 12 mmol/L). There was a high correlation between the values produced using different analytical techniques (r2 = .95), but mean values were different between treatments (frozen FP, frozen SC > immediate ISE > frozen ISE; P sweat sodium concentration estimates differed depending on the number of sites included in the calculation. Environmental testing conditions should be considered in the interpretation of results. The impact of sample freezing and subsequent analytical technique was small but statistically significant. Nevertheless, when undertaken using a standardized protocol, the regional absorbent-patch method appears to be a relatively robust field test.

  4. UV variability in Moscow according to long-term UV measurements and reconstruction model

    Directory of Open Access Journals (Sweden)

    N. Y. Chubarova

    2008-06-01

    Full Text Available Long-term measurements of erythemally weighted UV irradiance (Qer have been analyzed for the 1999–2006 period as well as UV variability according to a reconstruction model since 1968. The estimates of different atmospheric parameters effects, including NO2 content, on Qer have been obtained on seasonal and interannual scales. It has been shown that NO2 content in conditions of large megalopolis provides average Qer decrease of about 1.5–2%. The seasonal variations of the observed UV indices are discussed from the point of view of the impact on health. Using the reconstruction model we showed a distinct growth in Qer since 1980 due to changes in total ozone (+2.5% per decade, effective cloud amount transmission (+2.1% per decade and aerosol loading (+1.1% per decade. However, there is no change in Qer over the longer 1968–2006 period due to significant decrease in effective cloud amount transmission (−11% per decade in 1968–1980.

  5. UV variability in Moscow according to long-term UV measurements and reconstruction model

    Science.gov (United States)

    Chubarova, N. Y.

    2008-06-01

    Long-term measurements of erythemally weighted UV irradiance (Qer) have been analyzed for the 1999-2006 period as well as UV variability according to a reconstruction model since 1968. The estimates of different atmospheric parameters effects, including NO2 content, on Qer have been obtained on seasonal and interannual scales. It has been shown that NO2 content in conditions of large megalopolis provides average Qer decrease of about 1.5-2%. The seasonal variations of the observed UV indices are discussed from the point of view of the impact on health. Using the reconstruction model we showed a distinct growth in Qer since 1980 due to changes in total ozone (+2.5% per decade), effective cloud amount transmission (+2.1% per decade) and aerosol loading (+1.1% per decade). However, there is no change in Qer over the longer 1968-2006 period due to significant decrease in effective cloud amount transmission (-11% per decade) in 1968-1980.

  6. Continuous-variable Measurement-device-independent Quantum Relay Network with Phase-sensitive Amplifiers

    Science.gov (United States)

    Li, Fei; Zhao, Wei; Guo, Ying

    2017-09-01

    Continuous-variable (CV) measurement-device-independent (MDI) quantum cryptography is now heading towards solving the practical problem of implementing scalable quantum networks. In this paper, we show that a solution can come from deploying an optical amplifier in the CV-MDI system, aiming to establish a high-rate quantum network. We suggest an improved CV-MDI protocol using the EPR states coupled with optical amplifiers. It can implement a practical quantum network scheme, where the legal participants create the secret correlations by using EPR states connecting to an untrusted relay via insecure links and applying the multi-entangled Greenberger-Horne-Zeilinger (GHZ) state analysis at relay station. Despite the possibility that the relay could be completely tampered with and imperfect links are subject to the powerful attacks, the legal participants are still able to extract a secret key from network communication. The numerical simulation indicates that the quantum network communication can be achieved in an asymmetric scenario, fulfilling the demands of a practical quantum network. Furthermore, we show that the use of optical amplifiers can compensate the inherent imperfections and improve the secret key rate of the CV-MDI system.

  7. Improving Continuous-Variable Measurement-Device-Independent Multipartite Quantum Communication with Optical Amplifiers*

    Science.gov (United States)

    Guo, Ying; Zhao, Wei; Li, Fei; Huang, Duan; Liao, Qin; Xie, Cai-Lang

    2017-08-01

    The developing tendency of continuous-variable (CV) measurement-device-independent (MDI) quantum cryptography is to cope with the practical issue of implementing scalable quantum networks. Up to now, most theoretical and experimental researches on CV-MDI QKD are focused on two-party protocols. However, we suggest a CV-MDI multipartite quantum secret sharing (QSS) protocol use the EPR states coupled with optical amplifiers. More remarkable, QSS is the real application in multipartite CV-MDI QKD, in other words, is the concrete implementation method of multipartite CV-MDI QKD. It can implement a practical quantum network scheme, under which the legal participants create the secret correlations by using EPR states connecting to an untrusted relay via insecure links and applying the multi-entangled Greenberger-Horne-Zeilinger (GHZ) state analysis at relay station. Even if there is a possibility that the relay may be completely tampered, the legal participants are still able to extract a secret key from network communication. The numerical simulation indicates that the quantum network communication can be achieved in an asymmetric scenario, fulfilling the demands of a practical quantum network. Additionally, we illustrate that the use of optical amplifiers can compensate the partial inherent imperfections of detectors and increase the transmission distance of the CV-MDI quantum system.

  8. Entropy Measures in the Assessment of Heart Rate Variability in Patients with Cardiodepressive Vasovagal Syncope

    Directory of Open Access Journals (Sweden)

    Beata Graff

    2015-03-01

    Full Text Available Sample entropy (SampEn was reported to be useful in the assessment of the complexity of heart rate dynamics. Permutation entropy (PermEn is a new measure based on the concept of order and was previously shown to be accurate for short, non-stationary datasets. The aim of the present study is to assess if SampEn and PermEn obtained from baseline recordings might differentiate patients with various outcomes of the head-up tilt test (HUTT. Time-domain heart rate variability (HRV indices and several nonlinear parameters were calculated using 500 RR interval-long ECG recordings done before tilting in patients with a history suggesting vasovagal syncope. Groups of patients with so-called cardiodepressive vasovagal syncope (VVS_2 during HUTT and patients who did not faint during the test were compared. Two types of HUT tests were analyzed: with spontaneous (SB or controlled breathing (CB. In our study, SampEn was higher in VVS_2 patients during SB, and PermEn was higher in VVS_2 patients during CB. Irrespective of the type of breathing during the test, SampEn and PermEn were similar in patients with the same type of reaction during HUTT. The use of several entropy-based parameters seems to be useful in HRV assessment in patients with vasovagal fainting.

  9. Estimating regional methane surface fluxes: the relative importance of surface and GOSAT mole fraction measurements

    Directory of Open Access Journals (Sweden)

    A. Fraser

    2013-06-01

    Full Text Available We use an ensemble Kalman filter (EnKF, together with the GEOS-Chem chemistry transport model, to estimate regional monthly methane (CH4 fluxes for the period June 2009–December 2010 using proxy dry-air column-averaged mole fractions of methane (XCH4 from GOSAT (Greenhouse gases Observing SATellite and/or NOAA ESRL (Earth System Research Laboratory and CSIRO GASLAB (Global Atmospheric Sampling Laboratory CH4 surface mole fraction measurements. Global posterior estimates using GOSAT and/or surface measurements are between 510–516 Tg yr−1, which is less than, though within the uncertainty of, the prior global flux of 529 ± 25 Tg yr−1. We find larger differences between regional prior and posterior fluxes, with the largest changes in monthly emissions (75 Tg yr−1 occurring in Temperate Eurasia. In non-boreal regions the error reductions for inversions using the GOSAT data are at least three times larger (up to 45% than if only surface data are assimilated, a reflection of the greater spatial coverage of GOSAT, with the two exceptions of latitudes >60° associated with a data filter and over Europe where the surface network adequately describes fluxes on our model spatial and temporal grid. We use CarbonTracker and GEOS-Chem XCO2 model output to investigate model error on quantifying proxy GOSAT XCH4 (involving model XCO2 and inferring methane flux estimates from surface mole fraction data and show similar resulting fluxes, with differences reflecting initial differences in the proxy value. Using a series of observing system simulation experiments (OSSEs we characterize the posterior flux error introduced by non-uniform atmospheric sampling by GOSAT. We show that clear-sky measurements can theoretically reproduce fluxes within 10% of true values, with the exception of tropical regions where, due to a large seasonal cycle in the number of measurements because of clouds and aerosols, fluxes are within 15% of true fluxes. We evaluate our

  10. Importance of Leadership Style towards Quality of Care Measures in Healthcare Settings: A Systematic Review.

    Science.gov (United States)

    Sfantou, Danae F; Laliotis, Aggelos; Patelarou, Athina E; Sifaki-Pistolla, Dimitra; Matalliotakis, Michail; Patelarou, Evridiki

    2017-10-14

    Effective leadership of healthcare professionals is critical for strengthening quality and integration of care. This study aimed to assess whether there exist an association between different leadership styles and healthcare quality measures. The search was performed in the Medline (National Library of Medicine, PubMed interface) and EMBASE databases for the time period 2004-2015. The research question that guided this review was posed as: "Is there any relationship between leadership style in healthcare settings and quality of care?" Eighteen articles were found relevant to our research question. Leadership styles were found to be strongly correlated with quality care and associated measures. Leadership was considered a core element for a well-coordinated and integrated provision of care, both from the patients and healthcare professionals.

  11. Importance of Leadership Style towards Quality of Care Measures in Healthcare Settings: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Danae F. Sfantou

    2017-10-01

    Full Text Available Effective leadership of healthcare professionals is critical for strengthening quality and integration of care. This study aimed to assess whether there exist an association between different leadership styles and healthcare quality measures. The search was performed in the Medline (National Library of Medicine, PubMed interface and EMBASE databases for the time period 2004–2015. The research question that guided this review was posed as: “Is there any relationship between leadership style in healthcare settings and quality of care?” Eighteen articles were found relevant to our research question. Leadership styles were found to be strongly correlated with quality care and associated measures. Leadership was considered a core element for a well-coordinated and integrated provision of care, both from the patients and healthcare professionals.

  12. Importance of Leadership Style towards Quality of Care Measures in Healthcare Settings: A Systematic Review

    Science.gov (United States)

    Sfantou, Danae F.; Patelarou, Athina E.; Sifaki- Pistolla, Dimitra; Patelarou, Evridiki

    2017-01-01

    Effective leadership of healthcare professionals is critical for strengthening quality and integration of care. This study aimed to assess whether there exist an association between different leadership styles and healthcare quality measures. The search was performed in the Medline (National Library of Medicine, PubMed interface) and EMBASE databases for the time period 2004–2015. The research question that guided this review was posed as: “Is there any relationship between leadership style in healthcare settings and quality of care?” Eighteen articles were found relevant to our research question. Leadership styles were found to be strongly correlated with quality care and associated measures. Leadership was considered a core element for a well-coordinated and integrated provision of care, both from the patients and healthcare professionals. PMID:29036901

  13. Measurements of the Spatial Variability of Mean Wind Profiles Using Multiple Doppler Lidars over Distances less than 1 Km

    Science.gov (United States)

    Banta, R. M.; Choukulkar, A.; Brewer, A.; Lundquist, J. K.; Iungo, V.; Pichugina, Y. L.; Quelet, P. T.; Wolfe, D. E.; Oncley, S.; Sandberg, S.; Weickmann, A. M.; Delgado, R.; McCaffrey, K.

    2015-12-01

    Small differences in wind speed can translate to large differences in wind energy (WE) revenues, so WE decision making requires accurate measurements of wind profiles through the turbine rotor layer of the lower atmosphere. Advances in understanding and modeling of boundary-layer processes, also needed by WE, requires such measurements through an even deeper layer—at least the lowest few hundreds of meters. An important use for such accurate measured wind-profile data is in the initiation and verification of NWP models. This prospect raises several fundamental questions, such as, what does the modeled profile represent, how was the measured profile determined, and what if the profile had been measured from a different site within the grid cell? To address these questions, two experiments were conducted at the Boulder Atmospheric Observatory (BAO) in modestly complex terrain downwind of the mountains. The Lidar Uncertainty Measurement Experiment (LUMEX) in June-July 2014 featured 5 Doppler lidars (2 scanning), and XPIA in April-May 2015, 11 Doppler lidars, including 5 scanning systems. Two broad goals of these projects were to assess differences in scanning and other data acquisition procedures on the measurements, addressed in (Pichugina et al.) at this conference, and to evaluate the effects of varying spatial separations on differences in the measured winds, addressed in the present paper. Sonic anemometers every 50 m on the 300-m BAO tower were used as a reference for the wind calculations, as well as another profile location. Lidar scan data indicated terrain-related regions of stronger flow within the scan volume of more than 1 m/s that were at least semi-recurrent. This variability produced significant differences in mean rotor-level winds by 2 identical profiling lidars separated by 500 m. During XPIA, four of the scanning Doppler lidars performed intersecting elevation scans (vertical-slice or "RHI") to create 'virtual towers' at various separation

  14. Missing transverse energy measurement in ATLAS detector: first LHC data results and importance for physics study

    CERN Document Server

    Pizio, Caterina

    2010-01-01

    The Large Hadron Collider (LHC) at CERN started its operation at the end of November 2009, first at a centre-of-mass energy of 900 GeV, then, since March 2010, at 7 TeV. During this period the ATLAS experiment has collected a large number of proton-proton collision events, resulting up to now in an integrated luminosity of about 45 pb-1. A very good measurement of the missing transverse energy, ETmiss, is essential for many physics studies in ATLAS both for Standard Model channels, as W, Z bosons decaying to tau leptons or top quark decays, and for discovering channels. Events with large ETmiss are expected to be the key signature for new physics such as supersymmetry and extra dimensions. A good ETmiss measurement in terms of linearity and resolution is crucial for the efficient and accurate reconstruction of the Higgs boson mass when the Higgs boson decays to a pair of tau leptons. This thesis describes the first measurement of ETmiss in ATLAS with real data. The performance of the algorithm for ETmiss reco...

  15. Measure your septa release ratios: pheromone release ratio variability affected by rubber septa and solvent.

    Science.gov (United States)

    Kuenen, L P S; Siegel, Joel P

    2015-03-01

    The type of solvent and the volume used to load pheromone components onto rubber septa had significant effects on pheromone release ratios, the variability of those release ratios, and the recoverability of the volatile components during subsequent extraction with hexane. Volatile release ratios of synthetic Oriental fruit moth (OFM) pheromone and additional volatile compounds were determined using a gas chromatograph column as a volatile trap for rapid (≤1 hr) analysis from individual rubber septa. Volatile compound solutions were prepared in hexane, pentane, CH2Cl2, and methyl tert-butyl ether, and a 10, 33, or 100 μl aliquot of each solution was applied to rubber septa. Septa loaded with 100 μl of CH2Cl2 emitted significantly (P < 0.05) higher alcohol: acetate (OH:Ac) ratios than septa loaded with the other solvents, which were all similar. Release ratios of the alcohol and acetate components of the OFM pheromone components were assessed over a 3 week period using septa loaded with each solvent. Regardless of loading solvent, the OFM OH:Ac ratios declined logarithmically over 3 weeks; however, the decay slope from septa loaded with CH2Cl2 solutions was different from those of the other three solvents, which were nearly all the same. A high variability in OH:Ac release ratios was measured overall, regardless of the solvent used or the volume it was applied in. Four compounds of near-equal mass: 1-dodecanol, 1-dodecanal, methyl decanoate, and tridecane emitted different release ratios dependent on the solvent, hexane or CH2Cl2, with which a septum was loaded. The more polar and the greater the mass of the test compound, the slower it was emitted from a septum regardless of solvent. These combined results plus comparisons to earlier reports, suggest that researchers should empirically assess the release ratios from septa to be used in bioassays rather than just reporting the type of septum, ratios of compounds applied and solvent used to prepare them.

  16. Magnetic resonance sounding measurements for modeling of water flow transport in variably saturated porous media

    Science.gov (United States)

    Legchenko, Anatoly; Legout, Cédric; Descloitres, Marc

    2017-04-01

    Numerical modeling of water flow in partly saturated porous media requires knowledge of hydraulic properties of the media. The straightforward approach consists of directly measuring K(teta) and h(teta), which is challenging in many practically important applications. In-situ non-invasive measurements of K(teta) and h(teta) are even more difficult and probably impossible. Additionally, K(teta) and h(teta) are both scale dependent parameters. Under favorable conditions, surface geophysical methods may allow non-invasive identification of different geological formations and estimate of the porosity. A few papers report hydrogeological modeling considering water-saturated formations with integrated geophysical data (aquifer geometry, K and teta at saturation). However, modeling of water transport in partly saturated subsurface is more difficult task because it requires more extensive knowledge of soil hydraulic properties. We use Magnetic Resonance Sounding (MRS) method for non-invasive time-lapse measurements of the water content as an input into numerical modeling tool for hydrogeological modeling. However, MRS is not able to provide h(teta), which rest inaccessible. We propose an approach, which consists of performing infiltration tests (or observation of natural infiltration and monitoring rain water) and measuring corresponding variation of the water content in the subsurface. Then, we use a data base of soils with accurately known hydraulic properties. We try different soils for modeling water transport under our conditions (reproducing our experiment) and select one, which allows fitting experimentally observed variations in the water content. When such a soil is found we obtain K(teta) and h(teta). Thus, instead of looking for true hydraulic characteristics of the subsurface we obtain some equivalent media that allows reproducing our observations. We demonstrate the feasibility of our approach using simple 1-D models and commercially available software

  17. Measuring the importance of oil-related revenues in total fiscal income for Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Reyes-Loya, Manuel Lorenzo; Blanco, Lorenzo [Facultad de Economia, Universidad Autonoma de Nuevo Leon, Loma Redonda 1515 Pte., Col. Loma Larga, C.P. 64710, Monterrey, Nuevo Leon (Mexico)

    2008-09-15

    Revenues from oil exports are an important part of government budgets in Mexico. A time-series analysis is conducted using monthly data from 1990 to 2005 examining three different specifications to determine how international oil price fluctuations and government income generated from oil exports influence fiscal policy in Mexico. The behavior of government spending and taxation is consistent with the spend-tax hypothesis. The results show that there is an inverse relationship between oil-related revenues and tax revenue from non-oil sources. Fiscal policy reform is urgently needed in order to improve tax collection as oil reserves in Mexico become more and more depleted. (author)

  18. On the importance of Task 1 and error performance measures in PRP dual-task studies

    Directory of Open Access Journals (Sweden)

    Tilo eStrobach

    2015-04-01

    Full Text Available The Psychological Refractory Period (PRP paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and 2 are presented with variable stimulus onset asynchronies (SOAs and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e. decreasing SOAs do not increase RTs and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/ or error rates in Task 1. This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects.

  19. On the importance of Task 1 and error performance measures in PRP dual-task studies.

    Science.gov (United States)

    Strobach, Tilo; Schütz, Anja; Schubert, Torsten

    2015-01-01

    The psychological refractory period (PRP) paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and Task 2) are presented with variable stimulus onset asynchronies (SOAs) and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e., decreasing SOAs do not increase reaction times (RTs) and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates) show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/or error rates in Task 1). This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects.

  20. A unified multi-level model approach to assessing patient responsiveness including; return to normal, minimally important differences and minimal clinically important improvement for patient reported outcome measures.

    Science.gov (United States)

    Sayers, Adrian; Wylde, Vikki; Lenguerrand, Erik; Gooberman-Hill, Rachael; Dawson, Jill; Beard, David; Price, Andrew; Blom, Ashley W

    2017-07-21

    This article reviews and compares four commonly used approaches to assess patient responsiveness with a treatment or therapy (return to normal (RTN), minimal important difference (MID), minimal clinically important improvement (MCII), OMERACT-OARSI [Outcome Measures in Rheumatology-Osteoarthris Reseach Society International] (OO)) and demonstrates how each of the methods can be formulated in a multilevel modelling (MLM) framework. Cohort study. A cohort of patients undergoing total hip and knee replacement were recruited from a single UK National Health Service hospital. 400 patients from the Arthroplasty Pain Experience cohort study undergoing total hip (n=210) and knee (n=190) replacement who completed the Intermittent and Constant Osteoarthritis Pain questionnaire prior to surgery and then at 3, 6 and 12 months after surgery. The primary outcome was defined as a response to treatment following total hip or knee replacement. We compared baseline scores, change scores and proportion of individuals defined as 'responders' using traditional and MLM approaches with patient responsiveness. Using existing approaches, baseline and change scores are underestimated, and the variance of baseline and change scores overestimated in comparison with MLM approaches. MLM increases the proportion of individuals defined as responding in RTN, MID and OO criteria compared with existing approaches. Using MLM with the MCII criteria reduces the number of individuals identified as responders. MLM improves the estimation of the SD of baseline and change scores by explicitly incorporating measurement error into the model and avoiding regression to the mean when making individual predictions. Using refined definitions of responsiveness may lead to a reduction in misclassification when attempting to predict who does and does not respond to an intervention and clarifies the similarities between existing methods. © Article author(s) (or their employer(s) unless otherwise stated in the text

  1. Measuring time-frequency importance functions of speech with bubble noise.

    Science.gov (United States)

    Mandel, Michael I; Yoho, Sarah E; Healy, Eric W

    2016-10-01

    Listeners can reliably perceive speech in noisy conditions, but it is not well understood what specific features of speech they use to do this. This paper introduces a data-driven framework to identify the time-frequency locations of these features. Using the same speech utterance mixed with many different noise instances, the framework is able to compute the importance of each time-frequency point in the utterance to its intelligibility. The mixtures have approximately the same global signal-to-noise ratio at each frequency, but very different recognition rates. The difference between these intelligible vs unintelligible mixtures is the alignment between the speech and spectro-temporally modulated noise, providing different combinations of "glimpses" of speech in each mixture. The current results reveal the locations of these important noise-robust phonetic features in a restricted set of syllables. Classification models trained to predict whether individual mixtures are intelligible based on the location of these glimpses can generalize to new conditions, successfully predicting the intelligibility of novel mixtures. They are able to generalize to novel noise instances, novel productions of the same word by the same talker, novel utterances of the same word spoken by different talkers, and, to some extent, novel consonants.

  2. The importance of P-glycoprotein multidrug transporter activity measurement in patients with Helicobacter pylori infection.

    Science.gov (United States)

    Babić, Zarko; Kucisec-Tepes, Nastja; Troskot, Rosana; Dorosulić, Zdravko; Svoboda-Beusan, Ivna

    2009-12-01

    P-glycoprotein is important in local antibiotic resistance. Aim was to evaluate the role of P-glycoprotein in local antibiotic resistance in patients with antral gastritis during antibiotic therapy to Helicobacter pylori infection. In the group of 53 patients with pathohistologically verified gastritis and microbiologically confirmed H. pylori infection (no signs of antimicrobial resistance) we have determined P-glycoprotein activity in gastric mucosa biopsy specimens, and compared them with the P-glycoprotein activity in 12 control subjects with normal endoscopic findings. The H. pylori positive patients were treated according to Maastricht protocol with short-term 7-day therapy consisting of two antibiotics (amoxicillin and azithromycin/metronidazole and clarithromycin) and a proton pump inhibitor P-glycoprotein activity was determined in rhodamine dye efflux test and quantified by ratio of the mean fluorescence (RMF) in flow cytometry analysis. H. pylori was successfully eradicated in the first cycle in 20 patients, whereas therapy was continued in 33 patients. The mean pre-treatment RMF values were higher in patients with H. pylori infection then in control subjects (p RMF was also higher in patients with multiple therapeutic failure than in those with successful H. pylori eradication (p RMF increased significantly during the antibiotic therapy (p < 0.05). P-glycoprotein might be one of the causes of therapy failure in patients with H. pylori. Our study confirms the importance of quantitative evaluation of P-glycoprotein expression during antibiotic treatment response.

  3. Constructing Proxy Variables to Measure Adult Learners' Time Management Strategies in LMS

    Science.gov (United States)

    Jo, Il-Hyun; Kim, Dongho; Yoon, Meehyun

    2015-01-01

    This study describes the process of constructing proxy variables from recorded log data within a Learning Management System (LMS), which represents adult learners' time management strategies in an online course. Based on previous research, three variables of total login time, login frequency, and regularity of login interval were selected as…

  4. Comparison of Measures of Variability of Speech Movement Trajectories Using Synthetic Records.

    Science.gov (United States)

    Lucero, Jorge C.

    2005-01-01

    In speech research, it is often desirable to assess quantitatively the variability of a set of speech movement trajectories. This problem is studied here using synthetic trajectories, which consist of a common pattern and terms representing amplitude and phase variability. The results show that a technique for temporal alignment of the records…

  5. Local versus global measures of accuracy: an important distinction for diagnostic imaging.

    Science.gov (United States)

    Black, W C; Dwyer, A J

    1990-01-01

    Unlike many tests, diagnostic imaging provides information about the location of disease, in addition to its presence or absence. To account for this ability of imaging, the authors make the distinction between local and global measures of accuracy. Local pertains to each anatomic site of potential disease in the patient and the corresponding image, while global refers to all such sites, collectively. After making this distinction, the authors demonstrate two major problems with global sensitivity and specificity, which are more commonly reported than their local counterparts. First, global sensitivity, unlike local sensitivities, varies with the anatomic distribution of disease in the reference population. Second, the conventional global measures cannot be integrated with pretest knowledge about the anatomic distribution of disease. Consequently, predictive values based on global sensitivity and specificity under-estimate the probability of disease when imaging and clinical findings correlate anatomically and overestimate the probability when the findings do not correlate. The local versus global distinction supports the commonsense notion that information pertaining to the anatomic distribution of disease is crucial for test interpretation.

  6. Wilson's disease: the importance of measuring serum caeruloplasmin non-immunologically.

    Science.gov (United States)

    Walshe, J M

    2003-03-01

    Wilson's disease should be considered as a possible diagnosis in any child, adolescent or young adult with liver damage without other explanation, especially when haemolysis is present. However, it may also present in adolescents or young adults with neurological signs confined to the motor system. The first diagnostic screening test is the estimation of the serum caeruloplasmin and total serum copper concentrations, with calculation of the serum non-caeruloplasmin-bound ('free') copper. Serum caeruloplasmin, which contains copper, is best determined by measurement of its oxidase activity, as the immunonephelometric method measures both caeruloplasmin and the biologically inactive apo-form. Diagnosis may be confirmed by an elevated urinary copper excretion. All close relatives of an identified patient must be screened and, where doubt persists, investigation of the Wilson's gene at chromosome 13q14.3 can be employed. Lifelong follow-up studies are best conducted in a specialist centre. Compliance with chelating therapy (penicillamine or trientine) or administration of the metal antagonist tetrathiomolybdate or zinc is monitored by determination of the serum 'free' copper, which should be maintained at or near 1.6 micromol/L (10 microg/100 mL). Side-effects of therapy are detected by the estimation of urinary total protein, full blood count and erythrocyte sedimentation rate, clotting factors and liver function tests.

  7. Measuring edge importance: a quantitative analysis of the stochastic shielding approximation for random processes on graphs.

    Science.gov (United States)

    Schmidt, Deena R; Thomas, Peter J

    2014-04-17

    Mathematical models of cellular physiological mechanisms often involve random walks on graphs representing transitions within networks of functional states. Schmandt and Galán recently introduced a novel stochastic shielding approximation as a fast, accurate method for generating approximate sample paths from a finite state Markov process in which only a subset of states are observable. For example, in ion-channel models, such as the Hodgkin-Huxley or other conductance-based neural models, a nerve cell has a population of ion channels whose states comprise the nodes of a graph, only some of which allow a transmembrane current to pass. The stochastic shielding approximation consists of neglecting fluctuations in the dynamics associated with edges in the graph not directly affecting the observable states. We consider the problem of finding the optimal complexity reducing mapping from a stochastic process on a graph to an approximate process on a smaller sample space, as determined by the choice of a particular linear measurement functional on the graph. The partitioning of ion-channel states into conducting versus nonconducting states provides a case in point. In addition to establishing that Schmandt and Galán's approximation is in fact optimal in a specific sense, we use recent results from random matrix theory to provide heuristic error estimates for the accuracy of the stochastic shielding approximation for an ensemble of random graphs. Moreover, we provide a novel quantitative measure of the contribution of individual transitions within the reaction graph to the accuracy of the approximate process.

  8. Risk Mitigation Measures: An Important Aspect of the Environmental Risk Assessment of Pharmaceuticals

    Directory of Open Access Journals (Sweden)

    Markus Liebig

    2014-01-01

    Full Text Available Within EU marketing authorization procedures of human and veterinary medicinal products (HMP and VMP, an environmental risk assessment (ERA has to be performed. In the event that an unacceptable environmental risk is identified, risk mitigation measures (RMM shall be applied in order to reduce environmental exposure to the pharmaceutical. Within the authorization procedures of HMP, no RMM have been applied so far, except for specific precautions for the disposal of the unused medicinal product or waste materials. For VMP, a limited number of RMM do exist. The aim of this study was to develop consistent and efficient RMM. Therefore, existing RMM were compiled from a summary of product characteristics of authorized pharmaceuticals, and new RMM were developed and evaluated. Based on the results, appropriate RMM were applied within the authorization procedures of medicinal products. For HMP, except for the existing precautions for disposal, no further reasonable measures could be developed. For VMP, two specific precautions for disposal and 17 specific precautions for use in animals were proposed as RMM.

  9. Using multiple biomarkers and determinants to obtain a better measurement of oxidative stress: a latent variable structural equation model approach.

    Science.gov (United States)

    Eldridge, Ronald C; Flanders, W Dana; Bostick, Roberd M; Fedirko, Veronika; Gross, Myron; Thyagarajan, Bharat; Goodman, Michael

    2017-09-01

    Since oxidative stress involves a variety of cellular changes, no single biomarker can serve as a complete measure of this complex biological process. The analytic technique of structural equation modeling (SEM) provides a possible solution to this problem by modelling a latent (unobserved) variable constructed from the covariance of multiple biomarkers. Using three pooled datasets, we modelled a latent oxidative stress variable from five biomarkers related to oxidative stress: F 2 -isoprostanes (FIP), fluorescent oxidation products, mitochondrial DNA copy number, γ-tocopherol (Gtoc) and C-reactive protein (CRP, an inflammation marker closely linked to oxidative stress). We validated the latent variable by assessing its relation to pro- and anti-oxidant exposures. FIP, Gtoc and CRP characterized the latent oxidative stress variable. Obesity, smoking, aspirin use and β-carotene were statistically significantly associated with oxidative stress in the theorized directions; the same exposures were weakly and inconsistently associated with the individual biomarkers. Our results suggest that using SEM with latent variables decreases the biomarker-specific variability, and may produce a better measure of oxidative stress than do single variables. This methodology can be applied to similar areas of research in which a single biomarker is not sufficient to fully describe a complex biological phenomenon.

  10. Examining the Minimal Important Difference of Patient-reported Outcome Measures for Individuals with Knee Osteoarthritis

    DEFF Research Database (Denmark)

    Mills, Kathryn A G; Naylor, Justine M; Eyles, Jillian P

    2016-01-01

    OBJECTIVE: To examine the influence of different analytical methods, baseline covariates, followup periods, and anchor questions when establishing a minimal important difference (MID) for individuals with knee osteoarthritis (OA). Second, to propose MID for improving and worsening on the Knee...... injury and Osteoarthritis Outcome Score (KOOS). METHODS: Retrospective analysis of prospectively collected data from 272 patients with knee OA undergoing a multidisciplinary nonsurgical management strategy. The magnitude and rate of change as well as the influence of baseline covariates were examined...... for 5 KOOS subscales over 52 weeks. The MID for improving and worsening were investigated using 4 anchor-based methods. RESULTS: Waitlisted for joint replacement and exhibiting unilateral/bilateral symptoms influenced change in KOOS over time. Generally, low correlations between anchors and KOOS change...

  11. [An important variability factor in determination of urinary activity of N-acetyl-beta-D-glucosaminidase: contamination of urine with semen].

    Science.gov (United States)

    Pastoris, A; Artioli, D; Catalani, S; Alinovi, R; Sbaffi, A; Mutti, A; Apostoli, P

    2004-01-01

    Urinary N-acetyl-beta-D-glucosaminidase (U-NAG) and its isoenzyme B (U-NAG-B) have been demonstrated useful and early markers of renal damage, although they are present in many other tissues and organs. To evaluate semen contamination of the urine and its role in variability of U-NAG. To assess control group values beta2-microglobulin, retinol-binding protein and U-NAG were measured in the urine of 30 healthy, non-smoking and non metal-exposed adults (19 females and 11 males). In four urine samples U-NAG was higher than the method reference value (5 U/g creatinine), without increases in other functional markers. Microscope examination revealed the presence of sperm in these samples. U-NAG variability decreased after the exclusion of these four values. The role of contamination was confirmed by adding semen to urine: when semen to urine ratio was 1:1000, enzyme activity was more than twice the basal level. U-NAG variability is strongly increased by contamination with semen, where enzyme concentration (especially NAG-B) is very high. Increased excretion of U-NAG and of its iso-form (U-NAG-B) in males, not correlated with other renal alterations or with exposure to heavy metals or other renal toxic substances, should be carefully evaluated and microscopic observation is advisable to detect the presence of sperm in urine.

  12. Increase of Short-Term Heart Rate Variability Induced by Blood Pressure Measurements during Ambulatory Blood Pressure Monitoring

    OpenAIRE

    Attila Frigy; Annamária Magdás; Victor-Dan Moga; Ioana Georgiana Coteț; Miklós Kozlovszky; László Szilágyi

    2017-01-01

    Objective. The possible effect of blood pressure measurements per se on heart rate variability (HRV) was studied in the setting of concomitant ambulatory blood pressure monitoring (ABPM) and Holter ECG monitoring (HM). Methods. In 25 hypertensive patients (14 women and 11 men, mean age: 58.1 years), 24-hour combined ABPM and HM were performed. For every blood pressure measurement, 2-minute ECG segments (before, during, and after measurement) were analyzed to obtain time domain parameters of H...

  13. The importance of measuring macroprolactin in the differential diagnosis of hyperprolactinemic patients

    Directory of Open Access Journals (Sweden)

    Chih-Chin Lu

    2012-02-01

    Full Text Available This study investigated the differences in clinical and laboratory features as well as treatment response in 70 outpatients with macroprolactinemia and monomeric hyperprolactinemia treated with dopamine agonists. After precipitation of the patients’ serum samples with poly-ethylene-glycol (PEG, serum prolactin (PRL levels were measured. We also measured serum levels of luteinizing hormone (LH, follicle-stimulating hormone (FSH, estradiol for women and testosterone for men. Clinical symptoms and signs were recorded. All patients received brain magnetic resonance imaging (MRI. After excluding patients with macroadenoma, 66 patients were treated with the dopamine agonist cabergoline. After 1 year, the clinical responses to cabergoline were recorded and PRL levels measured. Of the initial 70 patients with hyperprolactinemia, 15 patients (21.4% were found to have macroprolactinemia, while the rest had monomeric hyperprolactinemia. The two groups did not differ with regard to galactorrhea, menstrual disturbances or impotence. There were no significant group differences in serum LH, FSH, estradiol or testosterone levels. Patients with macroprolactinemia, however, had a significantly lower infertility rate than those with true hyperprolactinemia (6.7% vs. 32.7%, p=0.005. A greater percentage of macroprolactinemic patients had normal MRI pituitary images than those with hyperprolactinemia (73.3% vs. 34.5%, p=0.029. Compared to those with true hyperprolactinemia, patients with macroprolactinemia were found to have no significant changes in clinical features and PRL levels after 1 year of cabergoline therapy (after PEG precipitation, pre- and post-PRL levels: 59.3±100.2 to 13.8±9.5 ng/mL vs. 6.1±5.3 to 5.1±4.3 ng/mL, p=0.002. In conclusion, while macroprolactinemia is a common cause of hyperprolactinemia, many clinical and laboratory features cannot be used reliably to differentiate macroprolactinemia from true hyperprolactinemia. Routine screening

  14. The importance of the boundary condition in the transport of intensity equation based phase measurement

    Science.gov (United States)

    Zhang, Jialin; Chen, Qian; Li, Jiaji; Zuo, Chao

    2017-02-01

    The transport of intensity equation (TIE) is a powerful tool for direct quantitative phase retrieval in microscopy imaging. However, there may be some problems when dealing with the boundary condition of the TIE. The previous work introduces a hard-edged aperture to the camera port of the traditional bright field microscope to generate the boundary signal for the TIE solver. Under this Neumann boundary condition, we can obtain the quantitative phase without any assumption or prior knowledge about the test object and the setup. In this paper, we will demonstrate the effectiveness of this method based on some experiments in practice. The micro lens array will be used for the comparison of two TIE solvers results based on introducing the aperture or not and this accurate quantitative phase imaging technique allows measuring cell dry mass which is used in biology to follow cell cycle, to investigate cell metabolism, or to address effects of drugs.

  15. The spatial variability of water chemistry and DOC in bog pools: the importance of slope position, diurnal turnover and pool type

    Science.gov (United States)

    Holden, Joseph; Turner, Ed; Baird, Andy; Beadle, Jeannie; Billett, Mike; Brown, Lee; Chapman, Pippa; Dinsmore, Kerry; Dooling, Gemma; Grayson, Richard; Moody, Catherine; Gee, Clare

    2017-04-01

    We have previously shown that marine influence is an important factor controlling regional variability of pool water chemistry in blanket peatlands. Here we examine within-site controls on pool water chemistry. We surveyed natural and artificial (restoration sites) bog pools at blanket peatland sites in northern Scotland and Sweden. DOC, pH, conductivity, dissolved oxygen, temperature, cations, anions and absorbance spectra from 220-750nm were sampled. We sampled changes over time but also conducted intensive spatial surveys within individual pools and between pools on the same sampling days at individual study sites. Artificial pools had significantly greater DOC concentrations and different spectral absorbance characteristics when compared to natural pools at all sites studied. Within-pool variability in water chemistry tended to be small, even for very large pools ( 400 m2), except where pools had a layer of loose, mobile detritus on their beds. In these instances rapid changes took place between the overlying water column and the mobile sediment layer wherein dissolved oxygen concentrations dropped from values of around 12-10 mg/L to values less than 0.5 mg/L over just 2-3 cm of the depth profile. Such strong contrasts were not observed for pools which had a hard peat floor and which lacked a significant detritus layer. Strong diurnal turnover occurred within the pools on summer days, including within small, shallow pools (e.g. control on several pool water chemistry variables including pH and DOC concentration with accumulation (higher concentrations) in pools that were located further downslope in both natural and artificial pool systems. These processes have important implications for our interpretation of water chemistry and gas flux data from pool systems, how we design our sampling strategies and how we upscale results.

  16. Completing the Picture: Importance of Considering Participatory Mapping for REDD+ Measurement, Reporting and Verification (MRV).

    Science.gov (United States)

    Beaudoin, Guillaume; Rafanoharana, Serge; Boissière, Manuel; Wijaya, Arief; Wardhana, Wahyu

    2016-01-01

    Remote sensing has been widely used for mapping land cover and is considered key to monitoring changes in forest areas in the REDD+ Measurement, Reporting and Verification (MRV) system. But Remote Sensing as a desk study cannot capture the whole picture; it also requires ground checking. Therefore, complementing remote sensing analysis using participatory mapping can help provide information for an initial forest cover assessment, gain better understanding of how local land use might affect changes, and provide a way to engage local communities in REDD+. Our study looked at the potential of participatory mapping in providing complementary information for remotely sensed maps. The research sites were located in different ecological and socio-economic contexts in the provinces of Papua, West Kalimantan and Central Java, Indonesia. Twenty-one maps of land cover and land use were drawn with local community participation during focus group discussions in seven villages. These maps, covering a total of 270,000ha, were used to add information to maps developed using remote sensing, adding 39 land covers to the eight from our initial desk assessment. They also provided additional information on drivers of land use and land cover change, resource areas, territory claims and land status, which we were able to correlate to understand changes in forest cover. Incorporating participatory mapping in the REDD+ MRV protocol would help with initial remotely sensed land classifications, stratify an area for ground checks and measurement plots, and add other valuable social data not visible at the RS scale. Ultimately, it would provide a forum for local communities to discuss REDD+ activities and develop a better understanding of REDD+.

  17. Measuring Edge Importance: A Quantitative Analysis of the Stochastic Shielding Approximation for Random Processes on Graphs

    Science.gov (United States)

    2014-01-01

    Mathematical models of cellular physiological mechanisms often involve random walks on graphs representing transitions within networks of functional states. Schmandt and Galán recently introduced a novel stochastic shielding approximation as a fast, accurate method for generating approximate sample paths from a finite state Markov process in which only a subset of states are observable. For example, in ion-channel models, such as the Hodgkin–Huxley or other conductance-based neural models, a nerve cell has a population of ion channels whose states comprise the nodes of a graph, only some of which allow a transmembrane current to pass. The stochastic shielding approximation consists of neglecting fluctuations in the dynamics associated with edges in the graph not directly affecting the observable states. We consider the problem of finding the optimal complexity reducing mapping from a stochastic process on a graph to an approximate process on a smaller sample space, as determined by the choice of a particular linear measurement functional on the graph. The partitioning of ion-channel states into conducting versus nonconducting states provides a case in point. In addition to establishing that Schmandt and Galán’s approximation is in fact optimal in a specific sense, we use recent results from random matrix theory to provide heuristic error estimates for the accuracy of the stochastic shielding approximation for an ensemble of random graphs. Moreover, we provide a novel quantitative measure of the contribution of individual transitions within the reaction graph to the accuracy of the approximate process. PMID:24742077

  18. Discrimination power of short-term heart rate variability measures for CHF assessment.

    Science.gov (United States)

    Pecchia, Leandro; Melillo, Paolo; Sansone, Mario; Bracale, Marcello

    2011-01-01

    In this study, we investigated the discrimination power of short-term heart rate variability (HRV) for discriminating normal subjects versus chronic heart failure (CHF) patients. We analyzed 1914.40 h of ECG of 83 patients of which 54 are normal and 29 are suffering from CHF with New York Heart Association (NYHA) classification I, II, and III, extracted by public databases. Following guidelines, we performed time and frequency analysis in order to measure HRV features. To assess the discrimination power of HRV features, we designed a classifier based on the classification and regression tree (CART) method, which is a nonparametric statistical technique, strongly effective on nonnormal medical data mining. The best subset of features for subject classification includes square root of the mean of the sum of the squares of differences between adjacent NN intervals (RMSSD), total power, high-frequencies power, and the ratio between low- and high-frequencies power (LF/HF). The classifier we developed achieved sensitivity and specificity values of 79.3 % and 100 %, respectively. Moreover, we demonstrated that it is possible to achieve sensitivity and specificity of 89.7 % and 100 %, respectively, by introducing two nonstandard features ΔAVNN and ΔLF/HF, which account, respectively, for variation over the 24 h of the average of consecutive normal intervals (AVNN) and LF/HF. Our results are comparable with other similar studies, but the method we used is particularly valuable because it allows a fully human-understandable description of classification procedures, in terms of intelligible "if … then …" rules.

  19. Passive in-home measurement of stride-to-stride gait variability comparing vision and Kinect sensing.

    Science.gov (United States)

    Stone, Erik E; Skubic, Marjorie

    2011-01-01

    We present an analysis of measuring stride-to-stride gait variability passively, in a home setting using two vision based monitoring techniques: anonymized video data from a system of two web-cameras, and depth imagery from a single Microsoft Kinect. Millions of older adults fall every year. The ability to assess the fall risk of elderly individuals is essential to allowing them to continue living safely in independent settings as they age. Studies have shown that measures of stride-to-stride gait variability are predictive of falls in older adults. For this analysis, a set of participants were asked to perform a number of short walks while being monitored by the two vision based systems, along with a marker based Vicon motion capture system for ground truth. Measures of stride-to-stride gait variability were computed using each of the systems and compared against those obtained from the Vicon.

  20. Helping Gulf shrimpers adopt safety measures: importance of partnerships and research to practice.

    Science.gov (United States)

    Levin, Jeffrey L; Gilmore, Karen; Carruth, Ann; Wickman, Amanda; Shepherd, Sara; Gallardo, Gilbert; Nonnenmann, Matthew

    2012-01-01

    Commercial fishing continues to be a dangerous line of work. There are many hazards and the work is complex, even on a small scale. Along the United States Gulf Coast, the make-up of the commercial fishing population is diverse, with many Vietnamese shrimpers. Cultural barriers can interfere with critical communication and with receptivity to necessary safety training. In the course of studying these factors, it became apparent that language was a significant barrier among Vietnamese shrimp fishermen learning sound signals and making Mayday calls, potentially contributing to adverse events. This article is a qualitative description of a pilot project in response to this observation and aimed at the development of a model simulating the bridge of a commercial fishing vessel (including horn blast and radio). The model is used to improve knowledge and skills of the fishermen by providing instruction in Vietnamese. As a Mayday call must be made in English, instructional aids are provided to assist fishermen in the exercise. This example of research to practice (r2p) demonstrates how research findings may enhance acquisition of safety knowledge and skills through development of these types of models as well sustainable instructional tools like the multi-lingual interactive CD described here. It further illustrates the importance of partnerships in the design and delivery of workplace safety training interventions. The model, instructional aids, and CD are timely as they coincide with new regulation which mandates certification of these competencies or skills.

  1. Realising the Real Benefits of Outsourcing: Measurement Excellence and Its Importance in Achieving Long Term Value

    Science.gov (United States)

    Oshri, Ilan; Kotlarsky, Julia

    These days firms are, more than ever, pressed to demonstrate returns on their investment in outsourcing. While the initial returns can always be associated with one-off cost cutting, outsourcing arrangements are complex, often involving inter-related high-value activities, which makes the realisation of long-term benefits from outsourcing ever more challenging. Executives in client firms are no longer satisfied with the same level of service delivery through the outsourcing lifecycle. They seek to achieve business transformation and innovation in their present and future services, beyond satisfying service level agreements (SLAs). Clearly the business world is facing a new challenge: an outsourcing delivery system of high-value activities that demonstrates value over time and across business functions. However, despite such expectations, many client firms are in the dark when trying to measure and quantify the return on outsourcing investments: results of this research show that less than half of all CIOs and CFOs (43%) have attempted to calculate the financial impact of outsourcing to their bottom line, indicating that the financial benefits are difficult to quantify (51%).

  2. The role and importance of ozone for atmospheric chemistry and methods for measuring its concentration

    Directory of Open Access Journals (Sweden)

    Marković Dragan M.

    2003-01-01

    Full Text Available Depending on where ozone resides, it can protect or harm life on Earth. The thin layer of ozone that surrounds Earth acts as a shield protecting the planet from irradiation by UV light. When it is close to the planet's surface, ozone is a powerful photochemical oxidant that damage, icons frescos, museum exhibits, rubber, plastic and all plant and animal life. Besides the basic properties of some methods for determining the ozone concentration in working and living conditions, this paper presents a detailed description of the electrochemical method. The basic properties of the electrochemical method are used in the construction of mobile equipment for determining the sum of oxidants in the atmosphere. The equipment was used for testing the determination of the ozone concentration in working rooms, where the concentration was at a high level and caused by UV radiation or electrostatic discharge. According to the obtained results, it can be concluded that this equipment for determining the ozone concentration in the atmosphere is very powerful and reproducible in measurements.

  3. Effect of trotting speed on kinematic variables measured by use of extremity-mounted inertial measurement units in nonlame horses performing controlled treadmill exercise.

    Science.gov (United States)

    Cruz, Antonio M; Vidondo, Beatriz; Ramseyer, Alessandra A; Maninchedda, Ugo E

    2018-02-01

    OBJECTIVE To assess effects of speed on kinematic variables measured by use of extremity-mounted inertial measurement units (IMUs) in nonlame horses performing controlled exercise on a treadmill. ANIMALS 10 nonlame horses. PROCEDURES 6 IMUs were attached at predetermined locations on 10 nonlame Franches Montagnes horses. Data were collected in triplicate during trotting at 3.33 and 3.88 m/s on a high-speed treadmill. Thirty-three selected kinematic variables were analyzed. Repeated-measures ANOVA was used to assess the effect of speed. RESULTS Significant differences between the 2 speeds were detected for most temporal (11/14) and spatial (12/19) variables. The observed spatial and temporal changes would translate into a gait for the higher speed characterized by increased stride length, protraction and retraction, flexion and extension, mediolateral movement of the tibia, and symmetry, but with similar temporal variables and a reduction in stride duration. However, even though the tibia coronal range of motion was significantly different between speeds, the high degree of variability raised concerns about whether these changes were clinically relevant. For some variables, the lower trotting speed apparently was associated with more variability than was the higher trotting speed. CONCLUSIONS AND CLINICAL RELEVANCE At a higher trotting speed, horses moved in the same manner (eg, the temporal events investigated occurred at the same relative time within the stride). However, from a spatial perspective, horses moved with greater action of the segments evaluated. The detected changes in kinematic variables indicated that trotting speed should be controlled or kept constant during gait evaluation.

  4. Sperm DNA damage output parameters measured by the alkaline Comet assay and their importance.

    Science.gov (United States)

    Simon, L; Aston, K I; Emery, B R; Hotaling, J; Carrell, D T

    2017-03-01

    The alkaline Comet assay has shown high diagnostic value to determine male reproductive health and prognostic ability to predict ART success. Here, spermatozoon was analysed in 47 fertile donors and 238 patients, including 132 couples undergoing ART [semen was collected: Group I - within 3 months of their treatment (n = 79); and Group II - 3 months prior to their treatment (n = 53)]. We introduce four Comet distribution plots (A, B1, B2 and C) by plotting the level of DNA damage (x-axis) and percentage of comets (y-axis). Fertile donors had low mean DNA damage, olive tail moment and per cent of spermatozoa with damage and increased type A plots. Comet parameters were associated with clinical pregnancies in Group I. About 66% of couples with type A distribution plot were successful after ART, whereas couples with type B1, B2 and C distribution plots achieved 56%, 44% and 33% pregnancies respectively. The efficiency of the Comet assay was due to complete decondensation process, where the compact sperm nuclear DNA (28.2 ± 0.2 μm 3 ) is decondensed to ~63 μm 3 (before lysis) and ~1018 μm 3 (after lysis). A combinational analysis of all the Comet output parameters may provide a comprehensive evaluation of patient's reproductive health as these parameters measure different aspects of DNA damage within the spermatozoa. © 2016 Blackwell Verlag GmbH.

  5. Measurement of Vapor Flow As an Important Source of Water in Dry Land Eco-Hydrology

    Science.gov (United States)

    Wang, Z.; He, Z.; Wang, Y.; Gao, Z.; Hishida, K.

    2014-12-01

    When the temperature of land surface is lower than that of air and deeper soils, water vapor gathers toward the ground surface where dew maybe formed depending on the prevailing dew point and wind speed. Some plants are able to absorb the dew and vapor flow while the soil can readily absorb both. Certain animals such as desert beetles and ants harvest the dew or fog for daily survival. Recently, it is also realized that the dew and vapor flow can be a life-saving amount of water for plant survival at the driest seasons of the year in arid and semi-arid regions. Researches are conducted to quantify the amount of near-surface vapor flow in arid and semi-arid regions in China and USA. Quantitative leaf water absorption and desorption functions were derived based on laboratory experiments. Results show that plant leaves absorb and release water at different speeds depending on species and varieties. The "ideal" native plants in the dry climates can quickly absorb water and slowly release it. This water-holding capacity of plant is characterized by the absorption and desorption functions derived for plant physiology and water balance studies. Field studies are conducted to measure the dynamic vapor flow movements from the atmosphere and the groundwater table to soil surface. Results show that dew is usually formed on soil and plant surfaces during the daily hours when the temperature gradients are inverted toward the soil surface. The amount of dew harvested using gravels on the soil surface was enough to support water melon agriculture on deserts. The vapor flow can be effectively intercepted by artificially seeded plants in semi-arid regions forming new forests. New studies are attempted to quantify the role of vapor flow for the survival of giant sequoias in the southern Sierra Nevada Mountains of California.

  6. Liver Stiffness Measurement in Psoriasis: Do Metabolic or Disease Factors Play the Important Role?

    Directory of Open Access Journals (Sweden)

    Jamrus Pongpit

    2016-01-01

    Full Text Available Background. An increased prevalence of metabolic syndrome including nonalcoholic fatty liver disease (NAFLD was reported in psoriasis. NAFLD can progress to nonalcoholic steatohepatitis and fibrosis. Transient elastography (TE is a noninvasive liver fibrosis assessment. We evaluated the prevalence of significant liver fibrosis or high liver stiffness measurement (LSM using the LSM cutoff over 7 kPa and its associated factors in psoriatic patients. Methods. Subjects underwent TE and ultrasonography. Univariate and multivariate analysis were performed for the associated factors. Results. One hundred and sixty-eight patients were recruited. Three patients were excluded due to TE failure. Mean BMI was 24.8±4.7 kg/m2. NAFLD, metabolic syndrome, and diabetes were seen in 105 (63.6%, 83 (50.3%, and 31 (18.8% patients. The total cumulative dose of methotrexate over 1.5 g was seen in 39 (23.6% patients. Mean LSM was 5.3±2.9 kPa. High LSM was found in 18 (11.0% patients. Waist circumference (OR: 1.24; 95% CI: 1.11–1.38; P=0.0002, diabetes (OR: 12.70; 95% CI: 1.84–87.70; P=0.010, and AST (OR: 1.08; 95% CI: 1.02–1.16; P=0.017 were associated with high LSM. Conclusion. 11% of psoriatic patients had significant liver fibrosis by high LSM. Waist circumference, diabetes, and AST level were the independent predictors.

  7. Commentary: variability in workplace exposures and the design of efficient measurement and control strategies

    NARCIS (Netherlands)

    A. Burdorf (Alex); M. van Tongeren

    2003-01-01

    textabstractKromhout et al.'s (1993) well-cited publication presented detailed information on statistical procedures to estimate the magnitude of exposure variability within and between workers, drawing from a large database on chemical exposures throughout industry. It

  8. Entropy Measures in the Assessment of Heart Rate Variability in Patients with Cardiodepressive Vasovagal Syncope

    National Research Council Canada - National Science Library

    Beata Graff; Grzegorz Graff; Danuta Makowiec; Agnieszka Kaczkowska; Dorota Wejer; Szymon Budrejko; Dariusz Kozlowski; Krzysztof Narkiewicz

    2015-01-01

    ...). Time-domain heart rate variability (HRV) indices and several nonlinear parameters were calculated using 500 RR interval-long ECG recordings done before tilting in patients with a history suggesting vasovagal syncope...

  9. Test-retest reliability of trunk motor variability measured by large-array surface electromyography.

    Science.gov (United States)

    Abboud, Jacques; Nougarou, François; Loranger, Michel; Descarreaux, Martin

    2015-01-01

    The objective of this study was to evaluate the test-retest reliability of the trunk muscle activity distribution in asymptomatic participants during muscle fatigue using large-array surface electromyography (EMG). Trunk muscle activity distribution was evaluated twice, with 3 to 4 days between them, in 27 asymptomatic volunteers using large-array surface EMG. Motor variability, assessed with 2 different variables (the centroid coordinates of the root mean square map and the dispersion variable), was evaluated during a low back muscle fatigue task. Test-retest reliability of muscle activity distribution was obtained using Pearson correlation coefficients. A shift in the distribution of EMG amplitude toward the lateral-caudal region of the lumbar erector spinae induced by muscle fatigue was observed. Moderate to very strong correlations were found between both sessions in the last 3 phases of the fatigue task for both motor variability variables, whereas weak to moderate correlations were found in the first phases of the fatigue task only for the dispersion variable. These findings show that, in asymptomatic participants, patterns of EMG activity are less reliable in initial stages of muscle fatigue, whereas later stages are characterized by highly reliable patterns of EMG activity. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

  10. Quantifying Intrinsic Variability of Sagittarius A* Using Closure Phase Measurements of the Event Horizon Telescope

    Science.gov (United States)

    Roelofs, Freek; Johnson, Michael D.; Shiokawa, Hotaka; Doeleman, Sheperd S.; Falcke, Heino

    2017-09-01

    General relativistic magnetohydrodynamic (GRMHD) simulations of accretion disks and jets associated with supermassive black holes show variability on a wide range of timescales. On timescales comparable to or longer than the gravitational timescale {t}G={GM}/{c}3, variation may be dominated by orbital dynamics of the inhomogeneous accretion flow. Turbulent evolution within the accretion disk is expected on timescales comparable to the orbital period, typically an order of magnitude larger than t G . For Sgr A*, t G is much shorter than the typical duration of a VLBI experiment, enabling us to study this variability within a single observation. Closure phases, the sum of interferometric visibility phases on a triangle of baselines, are particularly useful for studying this variability. In addition to a changing source structure, variations in observed closure phase can also be due to interstellar scattering, thermal noise, and the changing geometry of projected baselines over time due to Earth rotation. We present a metric that is able to distinguish the latter two from intrinsic or scattering variability. This metric is validated using synthetic observations of GRMHD simulations of Sgr A*. When applied to existing multi-epoch EHT data of Sgr A*, this metric shows that the data are most consistent with source models containing intrinsic variability from source dynamics, interstellar scattering, or a combination of those. The effects of black hole inclination, orientation, spin, and morphology (disk or jet) on the expected closure phase variability are also discussed.

  11. Spatial variability analysis of within-field winter wheat nitrogen and grain quality using canopy fluorescence sensor measurements

    Science.gov (United States)

    Wheat grain protein content (GPC) is a key component when evaluating wheat nutrition. It is also important to determine wheat GPC before harvest for agricultural and food process enterprises in order to optimize the wheat grading process. Wheat GPC across a field is spatially variable due to the inh...

  12. Measuring phenotypic variability and plasticity in influenza A virus using multispectral viral strains

    Science.gov (United States)

    Vahey, Michael

    Despite relevance to human health, the mechanisms of enveloped virus assembly remain largely mysterious. This is particularly true of influenza A virus (IAV), which (unlike viral capsids with stereotyped shape and composition) forms heterogeneous particles whose assembly cannot be described in terms of equilibrium thermodynamics. Although the ability to assemble into particles with diverse size and composition could have important implications for infectivity, understanding how virion-to-virion differences arise and how they ultimately influence virus replication has proven challenging due to the lack of available tools for studying the assembly process. To address this challenge and establish a dynamic picture of how IAV assembles, we have developed virus strains that harbor small, non-disruptive fluorescent tags on each of the virus's five major structural proteins. Using these multispectral strains, we are able to quantify the protein composition and dynamics of virions as they assemble in live infected cells - measurements that have been previously inaccessible, and which reveal subpopulations of virus that favor either the binding or destruction of host receptors. The occupancy of these different subpopulations is malleable, shifting in response to environmental stimuli, including antiviral drugs that block receptor-destruction. In complex environments like the human respiratory tract, this phenotypic diversity could act as an evolutionary hedge. We acknowledge the Burroughs Wellcome Fund and NIH NIGMS for supporting this work.

  13. A new family of standardized and symmetric indices for measuring the intensity and importance of plant neighbour effects

    NARCIS (Netherlands)

    Diaz Sierra, R.; Verwijmeren, M.; Rietkerk, M.G.; Resco de Dios, Victor; Baudena, M.

    Measurements of competition and facilitation between plants often rely upon intensity and importance indices that quantify the net effect of neighbours on the performance of a target plant. A systematic analysis of the mathematical behaviour of the indices is lacking and leads to structural

  14. Reduced Penetrance and Variable Expression of SCN5A Mutations and the Importance of Co-inherited Genetic Variants: Case Report and Review of the Literature

    Directory of Open Access Journals (Sweden)

    T. Robyns, MD.

    2014-05-01

    Full Text Available Mutations in the SCN5A gene are responsible for multiple phenotypical presentations including Brugada syndrome, long QT syndrome, progressive familial heart block, sick sinus syndrome, dilated cardiomyopathy, lone atrial fibrillation and multiple overlap syndromes. These different phenotypic expressions of a mutation in a single gene can be explained by variable expression and reduced penetrance. One of the possible explanations of these phenomena is the co-inheritance of genetic variants. We describe a family where the individuals exhibit a compound heterozygosity in the SCN5A gene including a mutation (R1632H and a new variant (M858L. Individuals with both the mutation and new variant present with a more severe phenotype including spontaneous atrial tachyarrhythmia at young age. We give an overview of the different phenotypes of "SCN5A disease" and discuss the importance of co-inherited genetic variants in the expression of SCN5A disease.

  15. Combining in situ measurements and altimetry to estimate volume, heat and salt transport variability through the Faroe–Shetland Channel

    Directory of Open Access Journals (Sweden)

    B. Berx

    2013-07-01

    Full Text Available From 1994 to 2011, instruments measuring ocean currents (Acoustic Doppler Current Profilers; ADCPs have been moored on a section crossing the Faroe–Shetland Channel. Together with CTD (Conductivity Temperature Depth measurements from regular research vessel occupations, they describe the flow field and water mass structure in the channel. Here, we use these data to calculate the average volume transport and properties of the flow of warm water through the channel from the Atlantic towards the Arctic, termed the Atlantic inflow. We find the average volume transport of this flow to be 2.7 ± 0.5 Sv (1 Sv = 106 m3 s–1 between the shelf edge on the Faroe side and the 150 m isobath on the Shetland side. The average heat transport (relative to 0 °C was estimated to be 107 ± 21 TW (1 TW = 1012 W and the average salt import to be 98 ± 20 × 106 kg s−1. Transport values for individual months, based on the ADCP data, include a large level of variability, but can be used to calibrate sea level height data from satellite altimetry. In this way, a time series of volume transport has been generated back to the beginning of satellite altimetry in December 1992. The Atlantic inflow has a seasonal variation in volume transport that peaks around the turn of the year and has an amplitude of 0.7 Sv. The Atlantic inflow has become warmer and more saline since 1994, but no equivalent trend in volume transport was observed.

  16. Reproducibility of heart rate variability parameters measured in healthy subjects at rest and after a postural change maneuver

    Directory of Open Access Journals (Sweden)

    E.M. Dantas

    2010-10-01

    Full Text Available Heart rate variability (HRV provides important information about cardiac autonomic modulation. Since it is a noninvasive and inexpensive method, HRV has been used to evaluate several parameters of cardiovascular health. However, the internal reproducibility of this method has been challenged in some studies. Our aim was to determine the intra-individual reproducibility of HRV parameters in short-term recordings obtained in supine and orthostatic positions. Electrocardiographic (ECG recordings were obtained from 30 healthy subjects (20-49 years, 14 men using a digital apparatus (sampling ratio = 250 Hz. ECG was recorded for 10 min in the supine position and for 10 min in the orthostatic position. The procedure was repeated 2-3 h later. Time and frequency domain analyses were performed. Frequency domain included low (LF, 0.04-0.15 Hz and high frequency (HF, 0.15-0.4 Hz bands. Power spectral analysis was performed by the autoregressive method and model order was set at 16. Intra-subject agreement was assessed by linear regression analysis, test of difference in variances and limits of agreement. Most HRV measures (pNN50, RMSSD, LF, HF, and LF/HF ratio were reproducible independent of body position. Better correlation indexes (r > 0.6 were obtained in the orthostatic position. Bland-Altman plots revealed that most values were inside the agreement limits, indicating concordance between measures. Only SDNN and NNv in the supine position were not reproducible. Our results showed reproducibility of HRV parameters when recorded in the same individual with a short time between two exams. The increased sympathetic activity occurring in the orthostatic position probably facilitates reproducibility of the HRV indexes.

  17. JPL field measurements at the Finney County, Kansas, test site, October 1976: Meteorological variables, surface reflectivity, surface and subsurface temperatures

    Science.gov (United States)

    Kahle, A. B.; Schieldge, J.; Paley, H. N.

    1977-01-01

    Data collected at the Finney County, Kansas test site as part of the Joint Soil Moisture Experiment (JSME) are presented here, prior to analysis, to provide all JSME investigators with an immediate source of primary information. The ground-truth measurements were taken to verify and complement soil moisture data taken by microwave and infrared sensors during aircraft overflights. Measurements were made of meteorological variables (air speed, temperature, relative humidity, and rainfall), surface reflectivity, and temperatures at and below the surface.

  18. Identification of biosecurity measures and spatial variables as potential risk factors for Aleutian disease in Danish mink farms

    DEFF Research Database (Denmark)

    Themudo, Goncalo Espregueira Cruz; Houe, Hans; Agger, Jens Frederik Gramstrup

    2012-01-01

    for the infection in this region based on logistic regression of spatial (environmental, neighbourhood) variables and biosecurity measures. Information on potential biosecurity (management) risk factors in the region was obtained from interviews in 342 registered farms in the region using a structured questionnaire...

  19. The vulnerability of Australian rural communities to climate variability and change: Part I—Conceptualising and measuring vulnerability

    NARCIS (Netherlands)

    Nelson, R.; Kokic, P.; Crimp, S.; Meinke, H.B.; Howden, S.M.

    2010-01-01

    Vulnerability is a term frequently used to describe the potential threat to rural communities posed by climate variability and change. Despite growing use of the term, analytical measures of vulnerability that are useful for prioritising and evaluating policy responses are yet to evolve. Demand for

  20. Do Two or More Multicomponent Instruments Measure the Same Construct? Testing Construct Congruence Using Latent Variable Modeling

    Science.gov (United States)

    Raykov, Tenko; Marcoulides, George A.; Tong, Bing

    2016-01-01

    A latent variable modeling procedure is discussed that can be used to test if two or more homogeneous multicomponent instruments with distinct components are measuring the same underlying construct. The method is widely applicable in scale construction and development research and can also be of special interest in construct validation studies.…

  1. Assessing spatio-temporal variability and trends in modelled and measured Greenland Ice Sheet albedo (2000-2013)

    NARCIS (Netherlands)

    Alexander, P. M.; Tedesco, M.; Fettweis, X.; Van De Wal, R. S W; Smeets, C. J P P; Van Den Broeke, M. R.

    2014-01-01

    Accurate measurements and simulations of Greenland Ice Sheet (GrIS) surface albedo are essential, given the role of surface albedo in modulating the amount of absorbed solar radiation and meltwater production. In this study, we assess the spatio-temporal variability of GrIS albedo during June, July,

  2. Power of tests for a dichotomous independent variable measured with error.

    Science.gov (United States)

    McCaffrey, Daniel F; Elliott, Marc N

    2008-06-01

    To examine the implications for statistical power of using predicted probabilities for a dichotomous independent variable, rather than the actual variable. An application uses 271,479 observations from the 2000 to 2002 CAHPS Medicare Fee-for-Service surveys. STUDY DESIGN AND DATA: A methodological study with simulation results and a substantive application to previously collected data. Researchers often must employ key dichotomous predictors that are unobserved but for which predictions exist. We consider three approaches to such data: the classification estimator (1); the direct substitution estimator (2); the partial information maximum likelihood estimator (3, PIMLE). The efficiency of (1) (its power relative to testing with the true variable) roughly scales with the square of one less the classification error. The efficiency of (2) roughly scales with the R(2) for predicting the unobserved dichotomous variable, and is usually more powerful than (1). Approach (3) is most powerful, but for testing differences in means of 0.2-0.5 standard deviations, (2) is typically more than 95 percent as efficient as (3). The information loss from not observing actual values of dichotomous predictors can be quite large. Direct substitution is easy to implement and interpret and nearly as efficient as the PIMLE.

  3. Measure your septa release ratios: pheromone release ratio variability affected by rubber septa and solvent

    Science.gov (United States)

    The type of solvent and volume of the solvent used to load pheromone/volatile components onto rubber septa had significant effects on release ratios, the variability of those release ratios, and the recoverability of the volatile components during subsequent extraction with hexane. Volatile release ...

  4. Multi-level IRT with measurement error in the predictor variables

    NARCIS (Netherlands)

    Fox, Gerardus J.A.; Glas, Cornelis A.W.

    1998-01-01

    A two-level regression model is imposed on the ability parameters in an item response theory (IRT) model. The advantage of using latent rather than observed scores as dependent variables of a multilevel model is that this offers the possibility of separating the influence of item difficulty and

  5. Measure Guideline: Replacing Single-Speed Pool Pumps with Variable Speed Pumps for Energy Savings

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, A.; Easley, S.

    2012-05-01

    The report evaluates potential energy savings by replacing traditional single-speed pool pumps with variable speed pool pumps, and provide a basic cost comparison between continued uses of traditional pumps verses new pumps. A simple step-by-step process for inspecting the pool area and installing a new pool pump follows.

  6. Validity of (Ultra-)Short Recordings for Heart Rate Variability Measurements

    NARCIS (Netherlands)

    Muñoz Venegas, M.L.; van Roon, A.; Riese, H.; Thio, C.; Oostenbroek, E.; Westrik, I.; de Geus, E.J.C.; Gansevoort, R.; Lefrandt, J.; Nolte, I.M.; Snieder, H.

    2015-01-01

    Objectives In order to investigate the applicability of routine 10s electrocardiogram (ECG) recordings for time-domain heart rate variability (HRV) calculation we explored to what extent these (ultra-)short recordings capture the "actual" HRV. Methods The standard deviation of normal-to-normal

  7. Measuring Theoretical Orientations of Counselor Trainees in Turkey: The Role of Personal and Professional Variables

    Science.gov (United States)

    Demir, Ilkay; Gazioglu, Esra Ismen

    2017-01-01

    The first aim of this study was to explore the reliability and validity of the Turkish version of the Theoretical Orientation Profile Scale-Revised, and the second aim was to understand the relative influence of personal and professional variables on the choice of a guiding theoretical orientation among Turkish counselor trainees. Results showed…

  8. Estimating forest variables from top-of-atmosphere radiance satellite measurements using coupled radiative transfer models

    NARCIS (Netherlands)

    Laurent, V.C.E.; Verhoef, W.; Clevers, J.G.P.W.; Schaepman, M.E.

    2011-01-01

    Traditionally, it is necessary to pre-process remote sensing data to obtain top of canopy (TOC) reflectances before applying physically-based model inversion techniques to estimate forest variables. Corrections for atmospheric, adjacency, topography, and surface directional effects are applied

  9. Magnetic field measurements and wind-line variability of OB-type stars

    NARCIS (Netherlands)

    Schnerr, R.S.; Henrichs, H.F.; Neiner, C.; Verdugo, E.; de Jong, J.; Geers, V.C.; Wiersema, K.; van Dalen, B.; Tijani, A.; Plaggenborg, B.; Rygl, K.L.J.

    2008-01-01

    Context. The first magnetic fields in O- and B-type stars that do not belong to the Bp-star class, have been discovered. The cyclic UV wind-line variability, which has been observed in a significant fraction of early-type stars, is likely to be related to such magnetic fields. Aims. We attempt to

  10. Improved theory of time domain reflectometry with variable coaxial cable length for electrical conductivity measurements

    Science.gov (United States)

    Although empirical models have been developed previously, a mechanistic model is needed for estimating electrical conductivity (EC) using time domain reflectometry (TDR) with variable lengths of coaxial cable. The goals of this study are to: (1) derive a mechanistic model based on multisection tra...

  11. Variability of indoor and outdoor VOC measurements: An analysis using variance components

    Science.gov (United States)

    Jia, Chunrong; Batterman, Stuart A.; Relyea, George E.

    2014-01-01

    This study examines concentrations of volatile organic compounds (VOCs) measured inside and outside of 162 residences in southeast Michigan, U.S.A. Nested analyses apportioned four sources of variation: city, residence, season, and measurement uncertainty. Indoor measurements were dominated by seasonal and residence effects, accounting for 50 and 31%, respectively, of the total variance. Contributions from measurement uncertainty (VOC concentrations can use multi-seasonal measurements at centralized locations. Error models showed that uncertainties at low concentrations might obscure effects of other factors. Variance component analyses can be used to interpret existing measurements, design effective exposure studies, and determine whether the instrumentation and protocols are satisfactory. PMID:21995872

  12. Increase of Short-Term Heart Rate Variability Induced by Blood Pressure Measurements during Ambulatory Blood Pressure Monitoring

    Directory of Open Access Journals (Sweden)

    Attila Frigy

    2017-01-01

    Full Text Available Objective. The possible effect of blood pressure measurements per se on heart rate variability (HRV was studied in the setting of concomitant ambulatory blood pressure monitoring (ABPM and Holter ECG monitoring (HM. Methods. In 25 hypertensive patients (14 women and 11 men, mean age: 58.1 years, 24-hour combined ABPM and HM were performed. For every blood pressure measurement, 2-minute ECG segments (before, during, and after measurement were analyzed to obtain time domain parameters of HRV: SDNN and rMSSD. Mean of normal RR intervals (MNN, SDNN/MNN, and rMSSD/MNN were calculated, too. Parameter variations related to blood pressure measurements were analyzed using one-way ANOVA with multiple comparisons. Results. 2281 measurements (1518 during the day and 763 during the night were included in the analysis. Both SDNN and SDNN/MNN had a constant (the same for 24-hour, daytime, and nighttime values and significant change related to blood pressure measurements: an increase during measurements and a decrease after them (p<0.01 for any variation. Conclusion. In the setting of combined ABPM and HM, the blood pressure measurement itself produces an increase in short-term heart rate variability. Clarifying the physiological basis and the possible clinical value of this phenomenon needs further studies.

  13. THE EFFECT OF PERFORMANCE MEASUREMENT SYSTEM AND REMUNERATION TO EMPLOYEE PERFORMANCE WITH ORGANIZATIONAL CULTURE AS A MODERATING VARIABLE

    Directory of Open Access Journals (Sweden)

    Dewi Noor Fatikhah Rokhimakhumullah

    2017-12-01

    Full Text Available This study aims to examine the effect of performance measurement system and remuneration on employee performance with organizational culture as moderating variable. This research uses survey research design with Partial Least Square (PLS data analysis. Respondents in this study are 66 employees who have structural positions in KPP Madya Malang and KPP Pratama Batu. The results showed that the performance measurement system can improve employee performance. The results of this study demonstrated that organizational culture as a moderating variable was able to strengthen the relationship of performance measurement system and remuneration to employee performance. In addition, the results of the study was unable to prove that remuneration can improve the employees’ performance, because the remuneration given by the directorate general of taxes is not accompanied by a good performance appraisal.

  14. Evaluation of Intra- and Inter-observer Measurement Variability of a Radiographic Stifle Osteoarthritis Scoring System in Dogs.

    Science.gov (United States)

    Wessely, Marlis; Brühschwein, Andreas; Schnabl-Feichter, Eva

    2017-11-01

    Objectives To evaluate the intra- and inter-observer measurement variability of an existing osteoarthritis (OA) stifle scoring system. Methods Paired caudocranial and mediolateral canine stifle radiographs were selected randomly. A total of 15 assessment points were evaluated independently and graded twice (integer numeric scale: 1-4) at an interval of 2 weeks by three observers with different levels of experience. The grades for each of the 15 factors were summed to obtain the OA score for each patient. Results The 15 independent assessment points measured by the three observers showed high reproducibility and low intra-observer variability. Inter-observer variability was also low (mean: 1.09 ± 4.99, 95% CI [confidence interval]: -0.35 to 2.55). The most discordant ratings among the three observers involved sesamoid bones of gastrocnemius muscle (assessment point 11 of 15) and popliteal surface of femur (assessment point 10 of 15). Clinical Significance A validated and feasible OA scoring method is prerequisite for reliable radiographic assessment of OA progression. The low overall inter- and intra-observer variabilities among the 15 independent measures of the OA scoring system presented herein support its feasibility for application in clinical practice as an objective tool for radiographic scoring of stifle OA. Schattauer GmbH Stuttgart.

  15. The psychological importance of collective assembly: Development and validation of the Tendency for Effervescent Assembly Measure (TEAM).

    Science.gov (United States)

    Gabriel, Shira; Valenti, Jennifer; Naragon-Gainey, Kristin; Young, Ariana F

    2017-11-01

    Although previous research suggests that connection to large, mostly anonymous groups is important for the fulfillment of psychological needs and a sense of psychological well-being, no measure exists to assess individual differences in this area. In 5 studies, we developed and provided support for the validity of the Tendency for Effervescent Assembly Measure (TEAM). Utilizing data from student and community samples, we conducted exploratory factor analyses to guide item selection for the scale (Study 1), evaluated the structure of the scale in an independent sample (Study 2), examined the convergent, discriminant, and incremental validity of the scale (Study 3), and assessed measurement invariance of the scale across different demographic groups (Study 4). Study 5 explored the role of social needs fulfillment in effervescent assembly, as well as examined the relationship of the scale with recent collective effervescence experiences. Results revealed that our final 11-item scale was unidimensional, with excellent internal consistency and good test-retest reliability over 2 months. Measurement invariance was established across gender, ethnicity, and religion, providing support for the validity of the measure across demographic subgroups. Importantly, the TEAM predicted decreased loneliness, increased positive feelings, a sense of meaning in one's life, self-awareness, and spiritual transcendence, above and beyond the effects of the big 5 factors of personality and collective and relational interdependence. Furthermore, results suggested that positive outcomes associated with the TEAM are because of social need fulfillment. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  16. Universal Quantum Computing with Measurement-Induced Continuous-Variable Gate Sequence in a Loop-Based Architecture

    Science.gov (United States)

    Takeda, Shuntaro; Furusawa, Akira

    2017-09-01

    We propose a scalable scheme for optical quantum computing using measurement-induced continuous-variable quantum gates in a loop-based architecture. Here, time-bin-encoded quantum information in a single spatial mode is deterministically processed in a nested loop by an electrically programmable gate sequence. This architecture can process any input state and an arbitrary number of modes with almost minimum resources, and offers a universal gate set for both qubits and continuous variables. Furthermore, quantum computing can be performed fault tolerantly by a known scheme for encoding a qubit in an infinite-dimensional Hilbert space of a single light mode.

  17. Compact energy consulting. The most important guidelines, measures and check lists; Energieberatung kompakt. Die wichtigsten Richtwerte, Massnahmen und Checklisten

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, Heinz P. [Deutsche Gesellschaft fuer Sonnenenergie e.V. (DGS), Muenchen (Germany)

    2010-07-01

    The numerous tables, illustrations and check lists in the compact paperback under consideration support the inventory, recommendation of suitable measures of reorganization, estimation of the energy saving and cost saving as well as the answer of the most important customer questions in counselling interviews locally. The paperback contains the following aspects: (a) construction units and heating systems in existing buildings; (b) stocktaking; (c) requirements on the Energy Saving Ordinance (EnEV) 2009; (d) measures of reorganization; (e) estimation of energy conservation and cost savings; (f) financing programs; (g) energy passports.

  18. Measurement of phi* variable in Drell-Yan events in p-p collisions with 8 TeV data

    CERN Document Server

    AUTHOR|(CDS)2087044

    2016-01-01

    Transverse momentum spectra of vector bosons in Drell-Yan events have always been interesting observables since they test the theoreticaldescription of the process. At lower end the spectrum tests the model ofunderlying event while the high tail can be compared with predictions fromperturbative QCD. However the measurements at LHC are limited due to theresolution in the measurement of momenta of the daughter leptons,electron and muon, in particular. A novel variable phistar has beenproposed recently which uses the angular correlation of the lepton pairsfrom Z decay to probe the transverse momenta the vector boson and hencehas less systematic error.Results from measurements at LHC will be presented in this talk.

  19. TWO MEASURES OF THE DEPENDENCE OF PREFERENTIAL RANKINGS ON CATEGORICAL VARIABLES

    Directory of Open Access Journals (Sweden)

    Lissowski Grzegorz

    2017-06-01

    Full Text Available The aim of this paper is to apply a general methodology for constructing statistical methods, which is based on decision theory, to give a statistical description of preferential rankings, with a focus on the rankings’ dependence on categorical variables. In the paper, I use functions of description errors that are based on the Kemeny and Hamming distances between preferential orderings, but the proposed methodology can also be applied to other methods of estimating description errors.

  20. Characterization of Common Measures of Heart Period Variability in Healthy Human Subjects: Implications for Patient Monitoring

    Science.gov (United States)

    2010-01-01

    5 min 31 ± 13 5 min Salo et al. [35] 32 ± 18 5 min Pitzalis et al. [37] 34 ± 23 5 min Pinna et al. [19] 85 ± 34a 800 beats Kuusela et al. [16] pNN50...Reproducibility of the heart rate variability responses to graded lower body negative pressure. Eur J Appl Physiol 2004; 92: 106–113. 35. Salo TM, Voipio-Pulkki

  1. Gait stability and variability measures show effects of impaired cognition and dual tasking in frail people

    OpenAIRE

    de Vries Oscar J; Appels Bregje A; van Campen Jos P; van Deudekom Floor J; Lamoth Claudine J; Pijnappels Mirjam

    2011-01-01

    Abstract Background Falls in frail elderly are a common problem with a rising incidence. Gait and postural instability are major risk factors for falling, particularly in geriatric patients. As walking requires attention, cognitive impairments are likely to contribute to an increased fall risk. An objective quantification of gait and balance ability is required to identify persons with a high tendency to fall. Recent studies have shown that stride variability is increased in elderly and under...

  2. A Multi-Component Proxy for OH Variability Measured from Space: Evaluation and Evolution

    Science.gov (United States)

    Murray, L. T.; Fiore, A. M.; Valin, L. C.

    2014-12-01

    Observed changes in the decay rate of methyl chloroform (MCF; CH3CCl3) have been the traditional top-down constraint for variability in tropospheric abundances of the hydroxyl radical (OH), and thereby the oxidative capacity of the atmosphere. However, as atmospheric MCF concentrations approach detection limits following its ban under the Montréal Protocol, it is necessary to identify new proxies for global OH and its variability. We present here a novel proxy for tropospheric OH using convolved observations of total and tropospheric columns of ozone, water vapor, NO2, and CO, available from the Aura and Aqua satellites in the NASA Earth Observing System constellation. Derived from photochemical steady-state assumptions, the satellite proxy generates spatiotemporally coherent monthly percent anomalies in column OH for Oct. 2004 through Sept. 2012. We demonstrate that the temporal evolution of the globally integrated signal is statistically consistent with changes inferred by the MCF decay rate during this period. The magnitude of interannual variability in the satellite OH proxy is smaller than that from MCF, more consistent with global chemical transport models (CTMs). We evaluate the proxy by comparing to 9-year hind-cast simulations of the GEOS-Chem global CTM driven by MERRA reanalysis meteorology at 2° x 2.5° horizontal resolution, and find that the satellite proxy correlates with the airmass-weighted tropospheric monthly mean OH anomalies (R = 0.6; n = 96 months). The satellite proxy and model simulations indicate regional-scale coherent OH anomalies for many regions and seasons; where discrepancies occur, we highlight possible causes. We present a source attribution of the spatial and temporal patterns in the satellite OH proxy, informed by the individual components of the satellite proxy, a series of zero-emission sensitivity simulations with GEOS-Chem, and independent proxies for major modes of climate variability.

  3. Measurement of Event Shape Variables in Deep-Inelastic Scattering at HERA

    CERN Document Server

    Aktas, A; Anthonis, T; Antunovic, B; Aplin, S; Asmone, A; Astvatsatourov, A; Babaev, A; Backovic, S; Bähr, J; Baghdasaryan, A; Baranov, P; Barrelet, E; Bartel, Wulfrin; Baudrand, S; Baumgartner, S; Becker, J; Beckingham, M; Behnke, O; Behrendt, O; Belousov, A; Berger, C; Berger, N; Bizot, J C; Boenig, M O; Boudry, V; Bracinik, J; Brandt, G; Brisson, V; Bruncko, Dusan; Büsser, F W; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Contreras, J G; Coughlan, J A; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; De Boer, Y; Delcourt, B; Del Degan, M; de Roeck, A; Desch, Klaus; De Wolf, E A; Diaconu, C; Dodonov, V; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Elsen, E; Erdmann, W; Essenov, S; Falkewicz, A; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Finke, L; Fleischer, M; Fleischmann, P; Flucke, G; Fomenko, A; Foresti, I; Franke, G; Frisson, T; Gabathuler, E; Garutti, E; Gayler, J; Gerlich, C; Ghazaryan, S; Ginzburgskaya, S; Glazov, A; Glushkov, I; Görlich, L; Goettlich, M; Gogitidze, N; Gorbounov, S; Goyon, C; Grab, C; Greenshaw, T; Gregori, M; Grell, B R; Grindhammer, G; Gwilliam, C; Haidt, D; Hajduk, L; Hansson, M; Heinzelmann, G; Henderson, R C W; Henschel, H; Herrera-Corral, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R P; Hovhannisyan, A; Hreus, T; Hussain, S; Ibbotson, M; Ismail, M; Jacquet, M; Janauschek, L; Janssen, X; Jemanov, V; Jönsson, L B; Johnson, D P; Jung, A W; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Klimkovich, T; Kluge, T; Knies, G; Knutsson, A; Korbel, V; Kostka, P; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Krüger, K; Kuckens, J; Landon, M P J; Lange, W; Laistoviicka, T; Lastoviicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Lindfeld, L; Lipka, K; Liptaj, A; List, B; List, J; Lobodzinska, E; Loktionova, N; López-Fernandez, R; Lubimov, V; Lucaci-Timoce, A I; Lüders, H; Lüke, D; Lux, T; Lytkin, L; Makankine, A; Malden, N; Malinovskii, E I; Mangano, S; Marage, P; Marshall, R; Martisikova, M; Martyn, H U; Maxfield, S J; Meer, D; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Milstead, D; Mladenov, D; Mohamed, A; Moreau, F; Morozov, A; Morris, J V; Mozer, M U; Müller, K; Murn, P; Nankov, K; Naroska, Beate; Naumann, T; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nozicka, M; Oganezov, R; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Papadopoulou, T D; Pascaud, C; Patel, G D; Peng, H; Pérez, E; Perez-Astudillo, D; Perieanu, A; Petrukhin, A; Pitzl, D; Placakyte, R; Portheault, B; Povh, B; Prideaux, P; Rahmat, A J; Raicevic, N; Reimer, P; Rimmer, A; Risler, C; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rurikova, Z; Rusakov, S; Salvaire, F; Sankey, D P C; Sauvan, E; Schatzel, S; Schmidt, S; Schmitt, S; Schmitz, C; Schoeffel, L; Schöning, A; Schultz-Coulon, H C; Sedlak, K; Sefkow, F; Shaw-West, R N; Shevyakov, I; Shtarkov, L N; Sloan, T; Smirnov, P; Soloviev, Yu; South, D; Spaskov, V; Specka, A; Steder, M; Stella, B; Stiewe, J; Strauch, I; Straumann, U; Sunar, D; Tchoulakov, V; Thompson, G; Thompson, P D; Tomasz, F; Traynor, D; Truöl, P; Tsakov, I; Tsipolitis, G; Tsurin, I; Turnau, J; Tzamariudaki, E; Urban, K; Urban, M; Usik, A; Utkin, D; Valkárová, A; Vallée, C; Van Mechelen, P; Vargas-Trevino, A; Vazdik, Ya A; Veelken, C; Vinokurova, S; Volchinski, V; Wacker, K; Wagner, J; Weber, G; Weber, R; Wegener, D; Werner, C; Wessels, M; Wessling, B; Wigmore, C; Wissing, C; Wolf, R; Wünsch, E; Xella, S M; Yan, W; Yeganov, V; Zaicek, J; Zaleisak, J; Zhang, Z; Zhelezov, A; Zhokin, A; Zhu, Y C; Zimmermann, J; Zimmermann, T; Zohrabyan, H; Zomer, F

    2006-01-01

    Deep-inelastic ep scattering data taken with the H1 detector at HERA and corresponding to an integrated luminosity of 106 pb^{-1} are used to study the differential distributions of event shape variables. These include thrust, jet broadening, jet mass and the C-parameter. The four-momentum transfer Q is taken to be the relevant energy scale and ranges between 14 GeV and 200 GeV. The event shape distributions are compared with perturbative QCD predictions, which include resummed contributions and analytical power law corrections, the latter accounting for non-perturbative hadronisation effects. The data clearly exhibit the running of the strong coupling alpha_s(Q) and are consistent with a universal power correction parameter alpha_0 for all event shape variables. A combined QCD fit using all event shape variables yields alpha_s(mZ) = 0.1198 \\pm 0.0013 ^{+0.0056}_{-0.0043} and alpha_0 = 0.476 \\pm 0.008 ^{+0.018} _{-0.059}.

  4. Time-Domain Sub-mm Astronomy. Measuring the Accretion Variability of Deeply Embedded Protostars.

    Science.gov (United States)

    Johnstone, Douglas

    2018-01-01

    During the protostellar phase of stellar evolution, accretion is expected to be variable, but this variability has been difficult to detect because protostars are deeply embedded. We have undertaken a 3-year dedicated JCMT/SCUBA-2 monitoring program of eight nearby star-forming regions (Herczeg et al. 2017) to search for sub-mm brightness variations as a proxy of episodic accretion. Here, we describe a sub-mm luminosity burst of the Class I protostar EC 53 in Serpens Main (Yoo et al. 2017). The change in sub-mm brightness of EC 53 is interpreted as dust heating in the envelope, generated by a luminosity increase of the protostar. The sub-mm lightcurve resembles the historical K-band lightcurve, which varies by a factor of ˜6 with a 543 period and is interpreted as accretion variability excited by interactions between the accretion disk and a close binary system. We further compare archival SCUBA-2 observations against the first year of our survey (Mairs et al. 2017) and perform a statistical analysis of the first eighteen months of the survey (Johnstone et al. 2017). We conclude that greater than 5% of the known deeply embedded protostars are found to vary in the sub-mm.

  5. On-shell constrained $M_2$ variables with applications to mass measurements and topology disambiguation

    CERN Document Server

    Cho, Won Sang; Kim, Doojin; Matchev, Konstantin T.; Moortgat, Filip; Pape, Luc; Park, Myeonghun

    2014-01-01

    We consider a class of on-shell constrained mass variables that are 3+1 dimensional generalizations of the Cambridge $M_{T2}$ variable and that automatically incorporate various assumptions about the underlying event topology. The presence of additional on-shell constraints causes their kinematic distributions to exhibit sharper endpoints than the usual $M_{T2}$ distribution. We study the mathematical properties of these new variables, e.g., the uniqueness of the solution selected by the minimization over the invisible particle 4-momenta. We then use this solution to reconstruct the masses of various particles along the decay chain. We propose several tests for validating the assumed event topology in missing energy events from new physics. The tests are able to determine: 1) whether the decays in the event are two-body or three-body, 2) if the decay is two-body, whether the intermediate resonances in the two decay chains are the same, and 3) the exact sequence in which the visible particles are emitted from ...

  6. Intra- and inter-individual variability in the mechanical properties of the human skin from in vivo measurements on 20 volunteers.

    Science.gov (United States)

    Jacquet, E; Chambert, J; Pauchot, J; Sandoz, P

    2017-11-01

    The mechanical properties and behavior of the human skin in vivo are of medical importance, particularly to surgeons who have to consider the skin extension capabilities in the preparation of surgical acts. Variable data can be found in literature that result from diverse kinds of tests (in vivo, ex vivo, and postmortem) performed with different instruments. This paper presents the results of in vivo measurements performed on a cohort of 20 healthy volunteers with an ultralight homemade uniaxial extensometer. Different anatomical zones were explored under different directions of solicitation in order to document inter- and intra-individual variability as well as skin anisotropy. The experimental data obtained are fitted with a phenomenological exponential model allowing the identification of three parameters characteristic of the tested skin behavior. These parameters can be related to the concept of skin extensibility used by surgeons. The inter- and intra-variability observed on that cohort confirms the need for a patient-specific approach based on the in vivo measurement of the mechanical behavior of the human skin of interest. Even the direction of higher skin stiffness is found to be individual-dependent. The capability of the extensometer used in this study to fulfill such measurement needs is also demonstrated. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Objectively measured sedentary time and associations with insulin sensitivity: Importance of reallocating sedentary time to physical activity.

    Science.gov (United States)

    Yates, Thomas; Henson, Joseph; Edwardson, Charlotte; Dunstan, David; Bodicoat, Danielle H; Khunti, Kamlesh; Davies, Melanie J

    2015-07-01

    The aim of this study is to quantify associations between objectively measured sedentary time and markers of insulin sensitivity by considering allocation into light-intensity physical activity or moderate- to vigorous-intensity physical activity (MVPA). Participants with an increased risk of impaired glucose regulation (IGR) were recruited (Leicestershire, United Kingdom, 2010-2011). Sedentary, light-intensity physical activity and MVPA time were measured using accelerometers. Fasting and 2-hour post-challenge insulin and glucose were assessed; insulin sensitivity was calculated by HOMA-IS and Matsuda-ISI. Isotemporal substitution regression models were used. Data were analysed in 2014. 508 participants were included (average age=65years, female=34%). Reallocating 30min of sedentary time into light-intensity physical activity was associated a 5% (95% CI 1, 9%; p=0.024) difference in Matsuda-ISI after adjustment for measured confounding variables. Reallocation into MVPA was associated with a 15% (7, 25%; p<0.001) difference in HOMA-IS and 18% (8, 28%; p<0.001) difference in Matsuda-ISI. Results for light-intensity physical activity were modified by IGR status with stronger associations seen in those with IGR. Reallocating sedentary time into light-intensity physical activity or MVPA was associated with differences in insulin sensitivity, with stronger and more consistent associations seen for MVPA. Copyright © 2015. Published by Elsevier Inc.

  8. Autonomy dimensions and care seeking for delivery in Zambia; the prevailing importance of cluster-level measurement

    Science.gov (United States)

    Gabrysch, Sabine; McMahon, Shannon A.; Siling, Katja; Kenward, Michael G.; Campbell, Oona M. R.

    2016-01-01

    It is widely held that decisions whether or when to attend health facilities for childbirth are not only influenced by risk awareness and household wealth, but also by factors such as autonomy or a woman’s ability to act upon her own preferences. How autonomy should be constructed and measured – namely, as an individual or cluster-level variable – has been less examined. We drew on household survey data from Zambia to study the effect of several autonomy dimensions (financial, relationship, freedom of movement, health care seeking and violence) on place of delivery for 3200 births across 203 rural clusters (villages). In multilevel logistic regression, two autonomy dimensions (relationship and health care seeking) were strongly associated with facility delivery when measured at the cluster level (OR 1.27 and 1.57, respectively), though not at the individual level. This suggests that power relations and gender norms at the community level may override an individual woman’s autonomy, and cluster-level measurement may prove critical to understanding the interplay between autonomy and care seeking in this and similar contexts. PMID:26931301

  9. The relative importance of water vapour and dust in controlling the variability in radiative heating of the summertime Saharan heat low

    Science.gov (United States)

    Marsham, John H.; Parker, Douglas J.; Todd, Martin C.; Banks, Jamie R.; Brindley, Helen E.; Garcia-Carreras, Luis; Roberts, Alexander J.; Ryder, Claire L.

    2017-04-01

    The summertime Sahara heat low (SHL) is a key component of the West African monsoon (WAM) system but is a key source of uncertainty in global models. There is considerable uncertainty over the relative importance of water vapour and dust concentrations in controlling the radiation budget over the Sahara. This limits our ability to explain the variability and trends in the SHL and WAM systems, and so hampers our ability to reduce model biases. Here we use in situ observations from Fennec supersite-1 in the central Sahara from June 2011 and 2012, as well as satellite retrievals from GERB, to quantify how total column water vapour (TCWV) and dust aerosols control day-to-day variability in the energy balance in observations and ECMWF reanalyses (ERA-I). Results show that the earth-atmosphere system is radiatively heated in June 2011 and 2012. While we are not able to completely disentangle the roles of water vapour, clouds and dust from the observations, the analysis demonstrates that TCWV provides a far stronger control on TOA net radiation, and so the net heating of the earth-atmosphere system, than AOD does. Variations in dust provide a much stronger control on surface heating, but the reduction in surface heating associated with high dust loadings are largely compensated by associated increases in atmospheric heating, and so dust control on net TOA radiation is weak. Dust and TCWV are both important for direct atmospheric heating. ERA-I assimilated radiosondes from the Fennec campaign but uses a monthly dust climatology, and so cannot capture the impact of daily variations in dustiness. Despite this, ERA-I managed to capture the control of TOA net flux by TCWV, with a positive correlation (r = 0.6) between observed and modelled TOA net radiation. Variations in surface net radiation, and so the vertical profile of radiative heating, are not captured in ERA-I, given it does not capture variations in dust. Results show that ventilation of the SHL by cool moist air

  10. Periorbital biometric measurements using ImageJ software: Standardisation of technique and assessment of intra- and interobserver variability

    Directory of Open Access Journals (Sweden)

    R Rajyalakshmi

    2017-01-01

    Full Text Available Purpose: To assess the reliability and repeatability of periorbital biometric measurements using ImageJ software and to assess if the horizontal visible iris diameter (HVID serves as a reliable scale for facial measurements. Methods: This study was a prospective, single-blind, comparative study. Two clinicians performed 12 periorbital measurements on 100 standardised face photographs. Each individual’s HVID was determined by Orbscan IIz and used as a scale for measurements using ImageJ software. All measurements were repeated using the ‘average’ HVID of the study population as a measurement scale. Intraclass correlation coefficient (ICC and Pearson product-moment coefficient were used as statistical tests to analyse the data. Results: The range of ICC for intra- and interobserver variability was 0.79–0.99 and 0.86–0.99, respectively. Test-retest reliability ranged from 0.66–1.0 to 0.77–0.98, respectively. When average HVID of the study population was used as scale, ICC ranged from 0.83 to 0.99, and the test-retest reliability ranged from 0.83 to 0.96 and the measurements correlated well with recordings done with individual Orbscan HVID measurements. Conclusion: Periorbital biometric measurements using ImageJ software are reproducible and repeatable. Average HVID of the population as measured by Orbscan is a reliable scale for facial measurements.