Sample records for random variables drawn

  1. Statistical auditing and randomness test of lotto k/N-type games

    NASA Astrophysics Data System (ADS)

    Coronel-Brizio, H. F.; Hernández-Montoya, A. R.; Rapallo, F.; Scalas, E.

    2008-11-01

    One of the most popular lottery games worldwide is the so-called “lotto k/N”. It considers N numbers 1,2,…,N from which k are drawn randomly, without replacement. A player selects k or more numbers and the first prize is shared amongst those players whose selected numbers match all of the k randomly drawn. Exact rules may vary in different countries. In this paper, mean values and covariances for the random variables representing the numbers drawn from this kind of game are presented, with the aim of using them to audit statistically the consistency of a given sample of historical results with theoretical values coming from a hypergeometric statistical model. The method can be adapted to test pseudorandom number generators.

  2. Effect of randomness in logistic maps

    NASA Astrophysics Data System (ADS)

    Khaleque, Abdul; Sen, Parongama

    2015-01-01

    We study a random logistic map xt+1 = atxt[1 - xt] where at are bounded (q1 ≤ at ≤ q2), random variables independently drawn from a distribution. xt does not show any regular behavior in time. We find that xt shows fully ergodic behavior when the maximum allowed value of at is 4. However , averaged over different realizations reaches a fixed point. For 1 ≤ at ≤ 4, the system shows nonchaotic behavior and the Lyapunov exponent is strongly dependent on the asymmetry of the distribution from which at is drawn. Chaotic behavior is seen to occur beyond a threshold value of q1(q2) when q2(q1) is varied. The most striking result is that the random map is chaotic even when q2 is less than the threshold value 3.5699⋯ at which chaos occurs in the nonrandom map. We also employ a different method in which a different set of random variables are used for the evolution of two initially identical x values, here the chaotic regime exists for all q1 ≠ q2 values.

  3. Scaling exponents for ordered maxima

    DOE PAGES

    Ben-Naim, E.; Krapivsky, P. L.; Lemons, N. W.

    2015-12-22

    We study extreme value statistics of multiple sequences of random variables. For each sequence with N variables, independently drawn from the same distribution, the running maximum is defined as the largest variable to date. We compare the running maxima of m independent sequences and investigate the probability S N that the maxima are perfectly ordered, that is, the running maximum of the first sequence is always larger than that of the second sequence, which is always larger than the running maximum of the third sequence, and so on. The probability S N is universal: it does not depend on themore » distribution from which the random variables are drawn. For two sequences, S N~N –1/2, and in general, the decay is algebraic, S N~N –σm, for large N. We analytically obtain the exponent σ 3≅1.302931 as root of a transcendental equation. Moreover, the exponents σ m grow with m, and we show that σ m~m for large m.« less

  4. Latin Hypercube Sampling (LHS) UNIX Library/Standalone

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

    2004-05-13

    The LHS UNIX Library/Standalone software provides the capability to draw random samples from over 30 distribution types. It performs the sampling by a stratified sampling method called Latin Hypercube Sampling (LHS). Multiple distributions can be sampled simultaneously, with user-specified correlations amongst the input distributions, LHS UNIX Library/ Standalone provides a way to generate multi-variate samples. The LHS samples can be generated either as a callable library (e.g., from within the DAKOTA software framework) or as a standalone capability. LHS UNIX Library/Standalone uses the Latin Hypercube Sampling method (LHS) to generate samples. LHS is a constrained Monte Carlo sampling scheme. Inmore » LHS, the range of each variable is divided into non-overlapping intervals on the basis of equal probability. A sample is selected at random with respect to the probability density in each interval, If multiple variables are sampled simultaneously, then values obtained for each are paired in a random manner with the n values of the other variables. In some cases, the pairing is restricted to obtain specified correlations amongst the input variables. Many simulation codes have input parameters that are uncertain and can be specified by a distribution, To perform uncertainty analysis and sensitivity analysis, random values are drawn from the input parameter distributions, and the simulation is run with these values to obtain output values. If this is done repeatedly, with many input samples drawn, one can build up a distribution of the output as well as examine correlations between input and output variables.« less

  5. Some limit theorems for ratios of order statistics from uniform random variables.

    PubMed

    Xu, Shou-Fang; Miao, Yu

    2017-01-01

    In this paper, we study the ratios of order statistics based on samples drawn from uniform distribution and establish some limit properties such as the almost sure central limit theorem, the large deviation principle, the Marcinkiewicz-Zygmund law of large numbers and complete convergence.

  6. Internal Communication and Job Satisfaction Revisited: The Impact of Organizational Trust and Influence on Commercial Bank Supervisors.

    ERIC Educational Resources Information Center

    Pincus, J. David; And Others

    Using H. Dennis' (1974) five-factor communication climate construct framework as a predictor variable, a study investigated the relationship between perceptions of communication climate and job satisfaction of supervisory employees in the banking industry. A systematic random sample was drawn from 68 commercial banks in Orange County, California,…

  7. Benford's law and continuous dependent random variables

    NASA Astrophysics Data System (ADS)

    Becker, Thealexa; Burt, David; Corcoran, Taylor C.; Greaves-Tunnell, Alec; Iafrate, Joseph R.; Jing, Joy; Miller, Steven J.; Porfilio, Jaclyn D.; Ronan, Ryan; Samranvedhya, Jirapat; Strauch, Frederick W.; Talbut, Blaine

    2018-01-01

    Many mathematical, man-made and natural systems exhibit a leading-digit bias, where a first digit (base 10) of 1 occurs not 11% of the time, as one would expect if all digits were equally likely, but rather 30%. This phenomenon is known as Benford's Law. Analyzing which datasets adhere to Benford's Law and how quickly Benford behavior sets in are the two most important problems in the field. Most previous work studied systems of independent random variables, and relied on the independence in their analyses. Inspired by natural processes such as particle decay, we study the dependent random variables that emerge from models of decomposition of conserved quantities. We prove that in many instances the distribution of lengths of the resulting pieces converges to Benford behavior as the number of divisions grow, and give several conjectures for other fragmentation processes. The main difficulty is that the resulting random variables are dependent. We handle this by using tools from Fourier analysis and irrationality exponents to obtain quantified convergence rates as well as introducing and developing techniques to measure and control the dependencies. The construction of these tools is one of the major motivations of this work, as our approach can be applied to many other dependent systems. As an example, we show that the n ! entries in the determinant expansions of n × n matrices with entries independently drawn from nice random variables converges to Benford's Law.

  8. Engineering Design Handbook. Army Weapon Systems Analysis. Part 2

    DTIC Science & Technology

    1979-10-01

    EXPERIMENTAL DESIGN ............................... ............ 41-3 41-5 RESULTS OF THE ASARS lIX SIMULATIONS ........................... 41-4 41-6 LATIN...sciences and human factors engineering fields utilizing experimental methodology and multi-variable statistical techniques drawn from experimental ...randomly to grenades for the test design . The nine experimental types of hand grenades (first’ nine in Table 33-2) had a "pip" on their spherical

  9. Comparison of Random Forest and Parametric Imputation Models for Imputing Missing Data Using MICE: A CALIBER Study

    PubMed Central

    Shah, Anoop D.; Bartlett, Jonathan W.; Carpenter, James; Nicholas, Owen; Hemingway, Harry

    2014-01-01

    Multivariate imputation by chained equations (MICE) is commonly used for imputing missing data in epidemiologic research. The “true” imputation model may contain nonlinearities which are not included in default imputation models. Random forest imputation is a machine learning technique which can accommodate nonlinearities and interactions and does not require a particular regression model to be specified. We compared parametric MICE with a random forest-based MICE algorithm in 2 simulation studies. The first study used 1,000 random samples of 2,000 persons drawn from the 10,128 stable angina patients in the CALIBER database (Cardiovascular Disease Research using Linked Bespoke Studies and Electronic Records; 2001–2010) with complete data on all covariates. Variables were artificially made “missing at random,” and the bias and efficiency of parameter estimates obtained using different imputation methods were compared. Both MICE methods produced unbiased estimates of (log) hazard ratios, but random forest was more efficient and produced narrower confidence intervals. The second study used simulated data in which the partially observed variable depended on the fully observed variables in a nonlinear way. Parameter estimates were less biased using random forest MICE, and confidence interval coverage was better. This suggests that random forest imputation may be useful for imputing complex epidemiologic data sets in which some patients have missing data. PMID:24589914

  10. Comparison of random forest and parametric imputation models for imputing missing data using MICE: a CALIBER study.

    PubMed

    Shah, Anoop D; Bartlett, Jonathan W; Carpenter, James; Nicholas, Owen; Hemingway, Harry

    2014-03-15

    Multivariate imputation by chained equations (MICE) is commonly used for imputing missing data in epidemiologic research. The "true" imputation model may contain nonlinearities which are not included in default imputation models. Random forest imputation is a machine learning technique which can accommodate nonlinearities and interactions and does not require a particular regression model to be specified. We compared parametric MICE with a random forest-based MICE algorithm in 2 simulation studies. The first study used 1,000 random samples of 2,000 persons drawn from the 10,128 stable angina patients in the CALIBER database (Cardiovascular Disease Research using Linked Bespoke Studies and Electronic Records; 2001-2010) with complete data on all covariates. Variables were artificially made "missing at random," and the bias and efficiency of parameter estimates obtained using different imputation methods were compared. Both MICE methods produced unbiased estimates of (log) hazard ratios, but random forest was more efficient and produced narrower confidence intervals. The second study used simulated data in which the partially observed variable depended on the fully observed variables in a nonlinear way. Parameter estimates were less biased using random forest MICE, and confidence interval coverage was better. This suggests that random forest imputation may be useful for imputing complex epidemiologic data sets in which some patients have missing data.

  11. Penetration and Growth Rates of Mobile Phones in Developing Countries: An Analytical Classification

    PubMed Central

    2010-01-01

    This brief paper uses a simple arithmetic framework to classify and explain the performance of developing countries in closing the absolute digital divide. Four categories are created on the basis of two variables, namely, the penetration and rate of growth of mobile phones. The paper answers questions such as: Which countries do well and badly on both variables? Are the countries in these categories drawn from specific regions or similar income levels or is the distribution more random? How can similar countries from the same region appear in two diametrically opposite categories? What does this imply for policy? PMID:20835391

  12. 11. 28'X40' original vellum, VariableAngle Launcher, 'INDEX TO Drawings' drawn ...

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

    11. 28'X40' original vellum, Variable-Angle Launcher, 'INDEX TO Drawings' drawn at no scale (P.W.DWG.No. 1781). - Variable Angle Launcher Complex, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  13. The effects of the one-step replica symmetry breaking on the Sherrington-Kirkpatrick spin glass model in the presence of random field with a joint Gaussian probability density function for the exchange interactions and random fields

    NASA Astrophysics Data System (ADS)

    Hadjiagapiou, Ioannis A.; Velonakis, Ioannis N.

    2018-07-01

    The Sherrington-Kirkpatrick Ising spin glass model, in the presence of a random magnetic field, is investigated within the framework of the one-step replica symmetry breaking. The two random variables (exchange integral interaction Jij and random magnetic field hi) are drawn from a joint Gaussian probability density function characterized by a correlation coefficient ρ, assuming positive and negative values. The thermodynamic properties, the three different phase diagrams and system's parameters are computed with respect to the natural parameters of the joint Gaussian probability density function at non-zero and zero temperatures. The low temperature negative entropy controversy, a result of the replica symmetry approach, has been partly remedied in the current study, leading to a less negative result. In addition, the present system possesses two successive spin glass phase transitions with characteristic temperatures.

  14. Modeling of Bacillus spores: Inactivation and Outgrowth

    DTIC Science & Technology

    2011-03-01

    there has to be a suitable amount of repair enzymes viable to accomplish this. 34 Let ( )r eE t be the enzyme concentration for the spore population...was drawn from a Gaussian fitness distribution with mean, 0E and variance, 0 2 E , 2 0 0 2 0 0 0 0 ( 0 0 ) 2 ( , 1 ) , , 2 0. E E E E E E f e EE ...time progresses, the evolution of the distribution of ( )r eE t will approach the kill threshold. Since 0E is a random variable, ( )r eE t is also a

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

    Dayman, Ken J; Ade, Brian J; Weber, Charles F

    High-dimensional, nonlinear function estimation using large datasets is a current area of interest in the machine learning community, and applications may be found throughout the analytical sciences, where ever-growing datasets are making more information available to the analyst. In this paper, we leverage the existing relevance vector machine, a sparse Bayesian version of the well-studied support vector machine, and expand the method to include integrated feature selection and automatic function shaping. These innovations produce an algorithm that is able to distinguish variables that are useful for making predictions of a response from variables that are unrelated or confusing. We testmore » the technology using synthetic data, conduct initial performance studies, and develop a model capable of making position-independent predictions of the coreaveraged burnup using a single specimen drawn randomly from a nuclear reactor core.« less

  16. NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 17: The relationship between seven variables and the use of US government technical reports by US aerospace engineers and scientists

    NASA Technical Reports Server (NTRS)

    Pinelli, Thomas E.; Barclay, Rebecca O.; Kennedy, John M.; Glassman, Nanci; Demerath, Loren

    1991-01-01

    A study was undertaken to investigate the relationship between the use of U.S. government technical reports by U.S. aerospace engineers and scientists and seven selected sociometric variables. Data were collected by means of a self-administered mail survey which was distributed to a randomly drawn sample of American Institute of Aeronautics and Astronautics (AIAA) members. Two research questions concerning the use of conference meeting papers, journal articles, in-house technical reports, and U.S. government technical reports were investigated. Relevance, technical quality, and accessibility were found to be more important determinants of the overall extent to which U.S. government technical reports and three other information products were used by U.S. aerospace engineers and scientists.

  17. Aggressive crime, alcohol and drug use, and concentrated poverty in 24 U.S. urban areas.

    PubMed

    Valdez, Avelardo; Kaplan, Charles D; Curtis, Russell L

    2007-01-01

    The nexus between substance use and aggressive crime involves a complex interrelationship among mediating individual and community-level variables. Using multilevel logistic regression models, we investigate how community-level concentration of poverty variables mediate the predictive relationships among individual level social attachment variables and substance use on aggressive crime in a large national sample of male arrestees (N = 20,602) drawn from 24 U.S. urban areas. The findings support our hypothesis that individual social attachments to marriage and the labor force (education and employment) are the principal individual-level pathway mediating the substance abuse/aggression nexus. In the random intercept model, 3.17% of the variation not explained by the individual-level predictor variables is attributable to community-level variation in urban area female-headed households and households receiving welfare. This confirms our hypothesis that social structural conditions of an urban environment differentially expose persons to conditions that predict being arrested for an aggressive crime. Our findings tend to counter the cultural theorists who argue for an indigenous culture of violence in inner-city ghettos and barrios.

  18. Factors associated with acceptance of peers with mental health problems in childhood and adolescence.

    PubMed

    Swords, Lorraine; Heary, Caroline; Hennessy, Eilis

    2011-09-01

    Research suggests that children's reactions to peers with mental health problems are related to the maintenance and outcomes of these problems. However, children's perceptions of such peers, particularly those with internalising problems, are neither well researched nor understood. The present study aimed to test a series of models relating socio-demographic and attributional variables to the acceptance of hypothetical boys and girls with attention deficit hyperactivity disorder (ADHD) and depression. A sample of 595 participants, drawn from five different age-groups spanning early childhood to late adolescence, completed a booklet of questions in response to two vignettes describing the behaviour of hypothetical target peers with depression and ADHD. The sample was drawn from schools randomly selected in the east of Ireland. The models indicated that age and gender of the participant, and the perceived responsibility of the target character for his/her condition, were the three most important predictors of acceptance in all models. However, the relationship between these variables and acceptance varied depending on the gender of the target child and the condition (depression or ADHD) in the models tested. The findings of the study suggest that the relationships between socio-demographic and attributional variables and acceptance of peers with mental health problems depend on the type of mental health problem under consideration. The findings have implications for the development of information and education programmes to improve the integration of children with mental health problems. © 2011 The Authors. Journal of Child Psychology and Psychiatry © 2011 Association for Child and Adolescent Mental Health.

  19. Against Popperized epidemiology.

    PubMed

    Jacobsen, M

    1976-03-01

    The recommendation of Popper's philosophy of science should be adopted by epidemiologists is disputed. Reference is made to other authors who have shown that the most constructive elements in Popper's ideas have been advocated by earlier philosophers and have been used in epidemiology without abandoning inductive reasoning. It is argued that Popper's denigration of inductive methods is particularly harmful to epidemiology. Inductive reasoning and statistical inference play a key role in the science; it is suggested that unfamiliarity with these ideas contributes to widespread misunderstanding of the function of epidemiology. Attention is drawn to a common fallacy involving correlations between three random variables. The prevalence of the fallacy may be related to confusion between deductive and inductive logic.

  20. [Discrimination of varieties of brake fluid using visual-near infrared spectra].

    PubMed

    Jiang, Lu-lu; Tan, Li-hong; Qiu, Zheng-jun; Lu, Jiang-feng; He, Yong

    2008-06-01

    A new method was developed to fast discriminate brands of brake fluid by means of visual-near infrared spectroscopy. Five different brands of brake fluid were analyzed using a handheld near infrared spectrograph, manufactured by ASD Company, and 60 samples were gotten from each brand of brake fluid. The samples data were pretreated using average smoothing and standard normal variable method, and then analyzed using principal component analysis (PCA). A 2-dimensional plot was drawn based on the first and the second principal components, and the plot indicated that the clustering characteristic of different brake fluid is distinct. The foregoing 6 principal components were taken as input variable, and the band of brake fluid as output variable to build the discriminate model by stepwise discriminant analysis method. Two hundred twenty five samples selected randomly were used to create the model, and the rest 75 samples to verify the model. The result showed that the distinguishing rate was 94.67%, indicating that the method proposed in this paper has good performance in classification and discrimination. It provides a new way to fast discriminate different brands of brake fluid.

  1. The Impact of Anxious and Calm Emotional States on Color Usage in Pre-Drawn Mandalas

    ERIC Educational Resources Information Center

    Kersten, Andrea; van der Vennet, Renee

    2010-01-01

    The purpose of this single-subject experiment was to test whether a link exists between emotional state and color usage in a common art therapy technique. The researchers hypothesized that when coloring a pre-drawn mandala, participants would choose warm colors when they were anxious and cool colors when they were calm. The non-random sample…

  2. Determinant of Household Business Scale of Moa Buffaloes at Moa Island Southwest Maluku Regency

    NASA Astrophysics Data System (ADS)

    Lainsamputty, J.; Roessali, W.; Santosa, S. I.; Eddy, B. T.

    2018-02-01

    The objective of this research was to analyze factors that affect the business scale of Moa buffaloes at Moa Island, Regency of Southwest Maluku. The research used a survey method with multistage random sampling. The location chosen was the District of Moa Lakor at Moa Island based on its largest buffalo population. Respondents were randomly drawn in a total of 120 respondents. The variables measured were years of experience in rearing animals, costs of production, farmer’s participation in group activities, animal housing systems, farmer’s income and farmer’s age. The statistical test used was the multiple linear regressions. The results showed that the mean of business scale in the area of high density of buffaloes population was 12.6 AU, in the moderate was 12.4 AU and in the low was 11.0 AU. The average of production cost was IDR 1.893.536.00/year, the average of revenue was IDR14.083.333.00/year, while the average of income was IDR 12.189.797.00/year. The independent variables simultaneously influence the business scale (P<0.01). Partially, experience, costs of production, participation and housing systems had highly significant influences on the business scale (P<0.01).

  3. Random Responding as a Threat to the Validity of Effect Size Estimates in Correlational Research

    ERIC Educational Resources Information Center

    Crede, Marcus

    2010-01-01

    Random responding to psychological inventories is a long-standing concern among clinical practitioners and researchers interested in interpreting idiographic data, but it is typically viewed as having only a minor impact on the statistical inferences drawn from nomothetic data. This article explores the impact of random responding on the size and…

  4. Under What Circumstances Does External Knowledge about the Correlation Structure Improve Power in Cluster Randomized Designs?

    ERIC Educational Resources Information Center

    Rhoads, Christopher

    2014-01-01

    Recent publications have drawn attention to the idea of utilizing prior information about the correlation structure to improve statistical power in cluster randomized experiments. Because power in cluster randomized designs is a function of many different parameters, it has been difficult for applied researchers to discern a simple rule explaining…

  5. Random Drug Testing of Students: Where Will the Line Be Drawn?

    ERIC Educational Resources Information Center

    Roberts, Nathan M.; Fossey, Richard

    2002-01-01

    Discusses several state and federal court cases testing the limits of school district efforts to expand the scope of random student drug-testing since the Supreme Court's 1995 decision in "Vernonia School District 47J v. Action," wherein the Court approved random drug-testing of student athletes in public high schools. (Contains 113…

  6. 89. 22'X34' original vellum, VariableAngle Launcher 'ELEVATION OF LAUNCHER BRIDGE ...

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

    89. 22'X34' original vellum, Variable-Angle Launcher 'ELEVATION OF LAUNCHER BRIDGE ON TEMPORARY SUPPORT' drawn at 1'=20'. (BUORD Sketch # 209786, PAPW 1932). - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  7. 90. 22'X34' original blueprint, VariableAngle Launcher, 'FRONT ELEVATION OF LAUNCHER ...

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

    90. 22'X34' original blueprint, Variable-Angle Launcher, 'FRONT ELEVATION OF LAUNCHER BRIDGE, CONNECTING BRIDGE AND BARGES' drawn at 1/4'=1'0'. (BUROD Sketch # 208247). - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  8. Enhancement in Informational Masking

    ERIC Educational Resources Information Center

    Cao, Xiang; Richards, Virginia M.

    2012-01-01

    Purpose: The ability to detect a tone added to a random masker improves when a preview of the masker is provided. In 2 experiments, the authors explored the role that perceptual organization plays in this release from masking. Method: Detection thresholds were measured in informational masking studies. The maskers were drawn at random prior to…

  9. Deterministic modelling and stochastic simulation of biochemical pathways using MATLAB.

    PubMed

    Ullah, M; Schmidt, H; Cho, K H; Wolkenhauer, O

    2006-03-01

    The analysis of complex biochemical networks is conducted in two popular conceptual frameworks for modelling. The deterministic approach requires the solution of ordinary differential equations (ODEs, reaction rate equations) with concentrations as continuous state variables. The stochastic approach involves the simulation of differential-difference equations (chemical master equations, CMEs) with probabilities as variables. This is to generate counts of molecules for chemical species as realisations of random variables drawn from the probability distribution described by the CMEs. Although there are numerous tools available, many of them free, the modelling and simulation environment MATLAB is widely used in the physical and engineering sciences. We describe a collection of MATLAB functions to construct and solve ODEs for deterministic simulation and to implement realisations of CMEs for stochastic simulation using advanced MATLAB coding (Release 14). The program was successfully applied to pathway models from the literature for both cases. The results were compared to implementations using alternative tools for dynamic modelling and simulation of biochemical networks. The aim is to provide a concise set of MATLAB functions that encourage the experimentation with systems biology models. All the script files are available from www.sbi.uni-rostock.de/ publications_matlab-paper.html.

  10. Predictors of psychological distress in low-income populations of Montreal.

    PubMed

    Caron, Jean; Latimer, Eric; Tousignant, Michel

    2007-01-01

    THEORETICAL PERSPECTIVE: Many epidemiologic studies agree that low-income populations are the groups most vulnerable to mental health problems. However, not all people in economic difficulty show symptoms, and it appears that having a social support network plays a role in protecting against the chronic stress resulting from conditions such as poverty. The aim of the study is to clarify the relative contribution of social support to the mental health of low-income populations in two neighbourhoods in the southwest of Montreal: Pointe-Saint Charles and Saint-Henri. A random sample of 416 social assistance recipients in southwest Montreal and another sample of 112 people, drawn at random from the general population, were interviewed. The psychological distress scale used was the Indice de détresse psychologique--Enquête Santê Quêbec (IDPESQ). The availability of social support components was assessed by using the Social Provisions Scale. Data were collected during interviews in the respondents' homes. Social support measures were entered into a multidimensional model including many variables identified as being associated with mental health. Multiple regression analysis identified the best predictors of psychological distress for the low-income population. Among the 30 variables included in a multiple regression analysis, emotional support and the presence of persons perceived as stressful together accounted for most of the variance in distress predicted by the model. Although younger people, people experiencing food insecurity and people with poorer numeracy show a higher level of distress, these variables make a fairly marginal contribution compared with that of social relations.

  11. Attendance at cultural events, reading books or periodicals, and making music or singing in a choir as determinants for survival: Swedish interview survey of living conditions.

    PubMed

    Bygren, L O; Konlaan, B B; Johansson, S E

    To investigate the possible influence of attendance at cultural events, reading books or periodicals, making music or singing in a choir as determinants for survival. A simple random sample was drawn of 15,198 individuals aged 16-74 years. Of these, 85% (12,982) were interviewed by trained non-medical interviewers between 1982 and 1983 about cultural activities. They were followed up with respect to survival until 31 December 1991. Swedish interview survey of living conditions comprising a random sample of the adult Swedish population. 12,675 people interviewed between 1982 and 1983. Survival of subjects after controlling for eight confounding variables: age, sex, education level, income, long term disease, social network, smoking, and physical exercise. 6,301 men and 6,374 women were followed up; 533 men and 314 women died during this period. The control variables influenced survival in the expected directions except for social network for men; a significant negative effective was found when the analysis was made separately for men and women. We found an influence on mortality when the eight control variables were controlled for in people who rarely attended events compared with those attending most often, the relative risk being 1.57 (95% confidence interval 1.18 to 2.09). Attendance at cultural events may have a positive influence on survival. Long term follow up of large samples with confounders that are well controlled for and with the cultural stimulation more highly specified should be used to try to falsify the hypothesis before experiments start.

  12. A Model for the Correlates of Students' Creative Thinking

    ERIC Educational Resources Information Center

    Sarsani, Mahender Reddy

    2007-01-01

    The present study was aimed to explore the relationships between orgainsational or school variables, students' personal background variables, and cognitive and motivational variables. The sample for the survey included 373 students drawn from nine Government schools in Andhra Pradesh, India. Students' creative thinking abilities were measured by…

  13. 13. 22'X34' original vellum, VariableAngle Launcher, 'SIDEVIEW CAMERA CAR TRACK ...

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

    13. 22'X34' original vellum, Variable-Angle Launcher, 'SIDEVIEW CAMERA CAR TRACK DETAILS' drawn at 1/4'=1'-0' (BUORD Sketch # 208078, PAPW 908). - Variable Angle Launcher Complex, Camera Car & Track, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  14. 10. 22'X34' original blueprint, VariableAngle Launcher, 'SIDE VIEW CAMERA CARSTEEL ...

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

    10. 22'X34' original blueprint, Variable-Angle Launcher, 'SIDE VIEW CAMERA CAR-STEEL FRAME AND AXLES' drawn at 1/2'=1'-0'. (BOURD Sketch # 209124). - Variable Angle Launcher Complex, Camera Car & Track, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  15. A Randomized Clinical Trial of Methadone Maintenance for Prisoners: Prediction of Treatment Entry and Completion in Prison

    PubMed Central

    GORDON, MICHAEL S.; KINLOCK, TIMOTHY W.; COUVILLION, KATHRYN A.; SCHWARTZ, ROBERT P.; O’GRADY, KEVIN

    2014-01-01

    The present report is an intent-to-treat analysis involving secondary data drawn from the first randomized clinical trial of prison-initiated methadone in the United States. This study examined predictors of treatment entry and completion in prison. A sample of 211 adult male prerelease inmates with preincarceration heroin dependence were randomly assigned to one of three treatment conditions: counseling only (counseling in prison; n= 70); counseling plus transfer (counseling in prison with transfer to methadone maintenance treatment upon release; n= 70); and counseling plus methadone (methadone maintenance in prison, continued in a community-based methadone maintenance program upon release; n= 71). Entered prison treatment (p <. 01), and completed prison treatment (p< .001) were significantly predicted by the set of 10 explanatory variables and favored the treatment conditions receiving methadone. The present results indicate that individuals who are older in age and have longer prison sentences may have better outcomes than younger individuals with shorter sentences, meaning they are more likely to enter and complete prison-based treatment. Furthermore, implications for the treatment of prisoners with prior heroin dependence and for conducting clinical trials may indicate the importance of examining individual characteristics and the possibility of the examination of patient preference. PMID:25392605

  16. A Randomized Clinical Trial of Methadone Maintenance for Prisoners: Prediction of Treatment Entry and Completion in Prison.

    PubMed

    Gordon, Michael S; Kinlock, Timothy W; Couvillion, Kathryn A; Schwartz, Robert P; O'Grady, Kevin

    2012-05-01

    The present report is an intent-to-treat analysis involving secondary data drawn from the first randomized clinical trial of prison-initiated methadone in the United States. This study examined predictors of treatment entry and completion in prison. A sample of 211 adult male prerelease inmates with preincarceration heroin dependence were randomly assigned to one of three treatment conditions: counseling only (counseling in prison; n= 70); counseling plus transfer (counseling in prison with transfer to methadone maintenance treatment upon release; n= 70); and counseling plus methadone (methadone maintenance in prison, continued in a community-based methadone maintenance program upon release; n= 71). Entered prison treatment (p <. 01), and completed prison treatment (p< .001) were significantly predicted by the set of 10 explanatory variables and favored the treatment conditions receiving methadone. The present results indicate that individuals who are older in age and have longer prison sentences may have better outcomes than younger individuals with shorter sentences, meaning they are more likely to enter and complete prison-based treatment. Furthermore, implications for the treatment of prisoners with prior heroin dependence and for conducting clinical trials may indicate the importance of examining individual characteristics and the possibility of the examination of patient preference.

  17. Differences in Mathematics Teachers' Perceived Preparedness to Demonstrate Competence in Secondary School Mathematics Content by Teacher Characteristics

    ERIC Educational Resources Information Center

    Ng'eno, J. K.; Chesimet, M. C.

    2016-01-01

    A sample of 300 mathematics teachers drawn from a population of 1500 participated in this study. The participants were selected using systematic random sampling and stratified random sampling (stratified by qualification and gender). The data was collected using self-report questionnaires for mathematics teachers. One tool was used to collect…

  18. Fisher, Sir Ronald Aylmer (1890-1962)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Statistician, born in London, England. After studying astronomy using AIRY's manual on the Theory of Errors he became interested in statistics, and laid the foundation of randomization in experimental design, the analysis of variance and the use of data in estimating the properties of the parent population from which it was drawn. Invented the maximum likelihood method for estimating from random ...

  19. Gender Differentiation in the New York "Times": 1885 and 1985.

    ERIC Educational Resources Information Center

    Jolliffe, Lee

    A study examined the descriptive language and sex-linked roles ascribed to women and men in articles of the New York "Times" from 1885 and 1985. Seven content analysis methods were applied to four random samples from the "Times"; one sample each for women and men from both years. Samples were drawn using randomly constructed…

  20. Self-esteem of young adults with chronic health conditions: appraising the effects of perceived impact.

    PubMed

    Ireys, H T; Gross, S S; Werthamer-Larsson, L A; Kolodner, K B

    1994-12-01

    The relationships between selected condition characteristics and self-esteem were investigated in a randomly drawn, community-based sample of 286 young adults with chronic illnesses and disabilities. Whether appraisals of the impact of the condition mediated relationships between condition characteristics and self-esteem, as measured by the Rosenberg Self-Esteem Scale, was also measured. As a group, the youth in this sample reported positive self-esteem. When sociodemographic and condition-related variables were considered simultaneously, maternal education, unpredictability of symptoms, prognosis, sensory impairment, and the presence of a co-occurring learning disability were found to have direct effects on esteem. Perceived impact mediated the relationship between condition characteristics and self-esteem. The results are discussed in relation to the role of impact appraisal in determining the emotional well-being of young adults with chronic illnesses.

  1. The reduction of occupational stress among elderly lawyers: the creation of a functional niche.

    PubMed

    Meltzer, M W

    1981-01-01

    The question of how older lawyers function in the context of what is generally a high stress occupation is examined from data drawn from a random stratified sample of 130 members of the legal profession. It is shown that elderly lawyers are able to reduce work stress (largely deriving from volume, responsibility, clients, and trials) by control over the quantity and focus of their work, as well as through client selection. Elderly lawyers are able to create a relatively stress free work role, which is in fact a functional niche for them within the profession. The result is high job satisfaction and low rates of retirement among elderly practitioners. Two factors: work role compensation and work role autonomy, are isolated from the legal data and proposed as important variables in a general theory of retirement behavior.

  2. Effect of breakfast on selected serum and cardiovascular variables

    NASA Technical Reports Server (NTRS)

    Frey, Mary A. B.; Merz, Marion P.; Hoffler, G. W.

    1992-01-01

    In view of the objections of many subjects to overnight fasting prior to their blood being drawn for analyses, the effect of eating breakfast on the results of subsequent blood analyses of selected blood constituents and on cardiovascular variables was investigated in 47 men and 34 women who were subjected to blood analyses on two occasions, one week apart: once fasting and once after breakfast. Results suggest that subjects need not fast overnight before blood is being drawn for determinations of the HDL-C levels, hemoglobin, hematocrit, total cholesterol, or phosphorus. However, based on other studies, it is suggested breakfast should not have a high content of fat.

  3. A Randomized Clinical Trial of Methadone Maintenance for Prisoners: Prediction of Treatment Entry and Completion in Prison

    ERIC Educational Resources Information Center

    Gordon, Michael S.; Kinlock, Timothy W.; Couvillion, Kathryn A.; Schwartz, Robert P.; O'Grady, Kevin

    2012-01-01

    The present report is an intent-to-treat analysis involving secondary data drawn from the first randomized clinical trial of prison-initiated methadone in the United States. This study examined predictors of treatment entry and completion in prison. A sample of 211 adult male prerelease inmates with preincarceration heroin dependence were randomly…

  4. Can Broad Inferences Be Drawn from Lottery Analyses of School Choice Programs? An Exploration of Appropriate Sensitivity Analyses

    ERIC Educational Resources Information Center

    Zimmer, Ron; Engberg, John

    2016-01-01

    School choice programs continue to be controversial, spurring a number of researchers into evaluating them. When possible, researchers evaluate the effect of attending a school of choice using randomized designs to eliminate possible selection bias. Randomized designs are often thought of as the gold standard for research, but many circumstances…

  5. The Malleability of Spatial Ability under Treatment of a FIRST LEGO League-Based Robotics Simulation

    ERIC Educational Resources Information Center

    Coxon, Steve V.

    2012-01-01

    A stratified random sample of volunteer participants (N = 75) aged 9 to 14 was drawn from 16 public school districts' gifted programs, including as many females (n = 28) and children from groups traditionally underrepresented in gifted programs (n = 18) as available. Participants were randomly divided into an experimental (n = 38) and a control…

  6. WORD FREQUENCY IN THE MODERN GERMAN SHORT STORY. FINAL REPORT.

    ERIC Educational Resources Information Center

    SCHERER, GEORGE A.; AND OTHERS

    A LIST OF THE MOST FREQUENTLY USED WORDS IN MODERN GERMAN SHORT STORIES WAS COMPILED. AN ANTHOLOGY OF 702 RECENTLY PUBLISHED, GERMAN SHORT STORIES WAS OBTAINED AND USED FOR A WORD COUNT, INVOLVING THE RANDOM SELECTION OF 4 WORDS IN EVERY 100-WORD PASSAGE. TWO INDEPENDENT RANDOM SAMPLES OF ABOUT 80,000 WORDS EACH WERE DRAWN FROM NEARLY 2 MILLION…

  7. Attendance at cultural events, reading books or periodicals, and making music or singing in a choir as determinants for survival: Swedish interview survey of living conditions.

    PubMed Central

    Bygren, L. O.; Konlaan, B. B.; Johansson, S. E.

    1996-01-01

    OBJECTIVES: To investigate the possible influence of attendance at cultural events, reading books or periodicals, making music or singing in a choir as determinants for survival. DESIGN: A simple random sample was drawn of 15,198 individuals aged 16-74 years. Of these, 85% (12,982) were interviewed by trained non-medical interviewers between 1982 and 1983 about cultural activities. They were followed up with respect to survival until 31 December 1991. SETTING: Swedish interview survey of living conditions comprising a random sample of the adult Swedish population. SUBJECTS: 12,675 people interviewed between 1982 and 1983. MAIN OUTCOME MEASURES: Survival of subjects after controlling for eight confounding variables: age, sex, education level, income, long term disease, social network, smoking, and physical exercise. RESULTS: 6,301 men and 6,374 women were followed up; 533 men and 314 women died during this period. The control variables influenced survival in the expected directions except for social network for men; a significant negative effective was found when the analysis was made separately for men and women. We found an influence on mortality when the eight control variables were controlled for in people who rarely attended events compared with those attending most often, the relative risk being 1.57 (95% confidence interval 1.18 to 2.09). CONCLUSION: Attendance at cultural events may have a positive influence on survival. Long term follow up of large samples with confounders that are well controlled for and with the cultural stimulation more highly specified should be used to try to falsify the hypothesis before experiments start. PMID:8990990

  8. Headache disorders in children and adolescents: their association with psychological, behavioral, and socio-environmental factors.

    PubMed

    Kröner-Herwig, Birgit; Gassmann, Jennifer

    2012-10-01

    This cross-sectional study on a randomly drawn population sample of children and adolescents (n = 3399; aged 9 to 15) aimed at the assessment of patterns of associations between psychosocial variables and primary headache disorders like migraine (MIG) or tension-type headache. A headache-free group served as a control. Data on headache and psychological trait variables (eg, internalizing symptoms), behavioral factors (eg, physical activities), and socio-environmental factors (eg, life events) were gathered by questionnaire. Logistic regression analyses were conducted with headache types (MIG, tension-type, and non-classifiable headache) as dependent variables. The pattern of correlations was largely congruent between the headache disorders. Associations were closest regarding maladaptive psychological traits (in particular internalizing symptoms with an odds ratio > 4 regarding MIG) compared with socio-environmental factors and particularly the behavioral factors. Unfavorable psychological traits and socio-environmental strains demonstrated distinctly stronger associations with MIG than tension-type headache and explained more variance in the occurrence of pediatric headache disorders than parental headache. Sex-specific analyses showed similarities as well as differences regarding the correlations, and in general, the associations were stronger in girls than boys. A common path model as posited by several researchers in the field may explain the parallelism in biopsychosocial vulnerability regarding the different headache disorders. © 2012 American Headache Society.

  9. A statistical, task-based evaluation method for three-dimensional x-ray breast imaging systems using variable-background phantoms

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

    Park, Subok; Jennings, Robert; Liu Haimo

    Purpose: For the last few years, development and optimization of three-dimensional (3D) x-ray breast imaging systems, such as digital breast tomosynthesis (DBT) and computed tomography, have drawn much attention from the medical imaging community, either academia or industry. However, there is still much room for understanding how to best optimize and evaluate the devices over a large space of many different system parameters and geometries. Current evaluation methods, which work well for 2D systems, do not incorporate the depth information from the 3D imaging systems. Therefore, it is critical to develop a statistically sound evaluation method to investigate the usefulnessmore » of inclusion of depth and background-variability information into the assessment and optimization of the 3D systems. Methods: In this paper, we present a mathematical framework for a statistical assessment of planar and 3D x-ray breast imaging systems. Our method is based on statistical decision theory, in particular, making use of the ideal linear observer called the Hotelling observer. We also present a physical phantom that consists of spheres of different sizes and materials for producing an ensemble of randomly varying backgrounds to be imaged for a given patient class. Lastly, we demonstrate our evaluation method in comparing laboratory mammography and three-angle DBT systems for signal detection tasks using the phantom's projection data. We compare the variable phantom case to that of a phantom of the same dimensions filled with water, which we call the uniform phantom, based on the performance of the Hotelling observer as a function of signal size and intensity. Results: Detectability trends calculated using the variable and uniform phantom methods are different from each other for both mammography and DBT systems. Conclusions: Our results indicate that measuring the system's detection performance with consideration of background variability may lead to differences in system performance estimates and comparisons. For the assessment of 3D systems, to accurately determine trade offs between image quality and radiation dose, it is critical to incorporate randomness arising from the imaging chain including background variability into system performance calculations.« less

  10. A comparative study of Conroy and Monte Carlo methods applied to multiple quadratures and multiple scattering

    NASA Technical Reports Server (NTRS)

    Deepak, A.; Fluellen, A.

    1978-01-01

    An efficient numerical method of multiple quadratures, the Conroy method, is applied to the problem of computing multiple scattering contributions in the radiative transfer through realistic planetary atmospheres. A brief error analysis of the method is given and comparisons are drawn with the more familiar Monte Carlo method. Both methods are stochastic problem-solving models of a physical or mathematical process and utilize the sampling scheme for points distributed over a definite region. In the Monte Carlo scheme the sample points are distributed randomly over the integration region. In the Conroy method, the sample points are distributed systematically, such that the point distribution forms a unique, closed, symmetrical pattern which effectively fills the region of the multidimensional integration. The methods are illustrated by two simple examples: one, of multidimensional integration involving two independent variables, and the other, of computing the second order scattering contribution to the sky radiance.

  11. A Comprehensive Comparison of Multiparty Secure Additions with Differential Privacy

    PubMed Central

    Goryczka, Slawomir; Xiong, Li

    2016-01-01

    This paper considers the problem of secure data aggregation (mainly summation) in a distributed setting, while ensuring differential privacy of the result. We study secure multiparty addition protocols using well known security schemes: Shamir’s secret sharing, perturbation-based, and various encryptions. We supplement our study with our new enhanced encryption scheme EFT, which is efficient and fault tolerant. Differential privacy of the final result is achieved by either distributed Laplace or Geometric mechanism (respectively DLPA or DGPA), while approximated differential privacy is achieved by diluted mechanisms. Distributed random noise is generated collectively by all participants, which draw random variables from one of several distributions: Gamma, Gauss, Geometric, or their diluted versions. We introduce a new distributed privacy mechanism with noise drawn from the Laplace distribution, which achieves smaller redundant noise with efficiency. We compare complexity and security characteristics of the protocols with different differential privacy mechanisms and security schemes. More importantly, we implemented all protocols and present an experimental comparison on their performance and scalability in a real distributed environment. Based on the evaluations, we identify our security scheme and Laplace DLPA as the most efficient for secure distributed data aggregation with privacy. PMID:28919841

  12. A Comprehensive Comparison of Multiparty Secure Additions with Differential Privacy.

    PubMed

    Goryczka, Slawomir; Xiong, Li

    2017-01-01

    This paper considers the problem of secure data aggregation (mainly summation) in a distributed setting, while ensuring differential privacy of the result. We study secure multiparty addition protocols using well known security schemes: Shamir's secret sharing, perturbation-based, and various encryptions. We supplement our study with our new enhanced encryption scheme EFT, which is efficient and fault tolerant. Differential privacy of the final result is achieved by either distributed Laplace or Geometric mechanism (respectively DLPA or DGPA), while approximated differential privacy is achieved by diluted mechanisms. Distributed random noise is generated collectively by all participants, which draw random variables from one of several distributions: Gamma, Gauss, Geometric, or their diluted versions. We introduce a new distributed privacy mechanism with noise drawn from the Laplace distribution, which achieves smaller redundant noise with efficiency. We compare complexity and security characteristics of the protocols with different differential privacy mechanisms and security schemes. More importantly, we implemented all protocols and present an experimental comparison on their performance and scalability in a real distributed environment. Based on the evaluations, we identify our security scheme and Laplace DLPA as the most efficient for secure distributed data aggregation with privacy.

  13. The modelling of carbon-based supercapacitors: Distributions of time constants and Pascal Equivalent Circuits

    NASA Astrophysics Data System (ADS)

    Fletcher, Stephen; Kirkpatrick, Iain; Dring, Roderick; Puttock, Robert; Thring, Rob; Howroyd, Simon

    2017-03-01

    Supercapacitors are an emerging technology with applications in pulse power, motive power, and energy storage. However, their carbon electrodes show a variety of non-ideal behaviours that have so far eluded explanation. These include Voltage Decay after charging, Voltage Rebound after discharging, and Dispersed Kinetics at long times. In the present work, we establish that a vertical ladder network of RC components can reproduce all these puzzling phenomena. Both software and hardware realizations of the network are described. In general, porous carbon electrodes contain random distributions of resistance R and capacitance C, with a wider spread of log R values than log C values. To understand what this implies, a simplified model is developed in which log R is treated as a Gaussian random variable while log C is treated as a constant. From this model, a new family of equivalent circuits is developed in which the continuous distribution of log R values is replaced by a discrete set of log R values drawn from a geometric series. We call these Pascal Equivalent Circuits. Their behaviour is shown to resemble closely that of real supercapacitors. The results confirm that distributions of RC time constants dominate the behaviour of real supercapacitors.

  14. The Academic Library and Student Retention and Graduation: An Exploratory Study

    ERIC Educational Resources Information Center

    Crawford, Gregory A.

    2015-01-01

    This study analyzed the relationships between variables of institutional expenses, library expenses, and library use and variables representing graduation and retention rates for colleges and universities. Using data drawn from the Integrated Postsecondary Educational Data System and the Academic Library Survey, institutions were compared by their…

  15. Representative Sampling: Follow-up of Spring 1972 and Spring 1973 Students. TEX-SIS FOLLOW-UP SC3.

    ERIC Educational Resources Information Center

    Wilkinson, Larry; And Others

    This report presents the findings of a research study, conducted by the College of the Mainland (COM) as a subcontractor for Project FOLLOW-UP, designed to test the accuracy of random sampling and to measure non-response bias in mail surveys. In 1975, a computer-generated random sample of 500 students was drawn from a population of 1,256 students…

  16. Multipartite nonlocality and random measurements

    NASA Astrophysics Data System (ADS)

    de Rosier, Anna; Gruca, Jacek; Parisio, Fernando; Vértesi, Tamás; Laskowski, Wiesław

    2017-07-01

    We present an exhaustive numerical analysis of violations of local realism by families of multipartite quantum states. As an indicator of nonclassicality we employ the probability of violation for randomly sampled observables. Surprisingly, it rapidly increases with the number of parties or settings and even for relatively small values local realism is violated for almost all observables. We have observed this effect to be typical in the sense that it emerged for all investigated states including some with randomly drawn coefficients. We also present the probability of violation as a witness of genuine multipartite entanglement.

  17. Relationships between sleeping habits, sedentary leisure activities and childhood overweight and obesity.

    PubMed

    Busto-Zapico, Raquel; Amigo-Vázquez, Isaac; Peña-Suárez, Elsa; Fernández-Rodríguez, Concepción

    2014-01-01

    The aim of this study is to show how sedentary leisure activities and a decrease in hours of sleep interact to lead to an increase in the body mass index (BMI) in children. A random sample of 291 nine-year-old and ten-year-old schoolchildren from Asturias (Spain) was taken. A cross-sectional design was used, the children's weight and height were measured and an individual interview was carried out. Using path analysis, a model was tested in which bedtime, the number of hours spent sleeping and sedentary leisure activities were the independent variables and the BMI was the dependent variable. The results show that sedentary leisure activities and hours spent sleeping are predictors of a greater BMI in children. Moreover, the effect of the time spent sleeping is mediated by sedentary leisure activities. That is to say, it is those children who go to bed late and who use that extra time to watch the television or play with the computer that tend to have a greater BMI. Attention should be drawn to the importance of this fact and to the implications it may have for education and children's health.

  18. Observed intra-cluster correlation coefficients in a cluster survey sample of patient encounters in general practice in Australia

    PubMed Central

    Knox, Stephanie A; Chondros, Patty

    2004-01-01

    Background Cluster sample study designs are cost effective, however cluster samples violate the simple random sample assumption of independence of observations. Failure to account for the intra-cluster correlation of observations when sampling through clusters may lead to an under-powered study. Researchers therefore need estimates of intra-cluster correlation for a range of outcomes to calculate sample size. We report intra-cluster correlation coefficients observed within a large-scale cross-sectional study of general practice in Australia, where the general practitioner (GP) was the primary sampling unit and the patient encounter was the unit of inference. Methods Each year the Bettering the Evaluation and Care of Health (BEACH) study recruits a random sample of approximately 1,000 GPs across Australia. Each GP completes details of 100 consecutive patient encounters. Intra-cluster correlation coefficients were estimated for patient demographics, morbidity managed and treatments received. Intra-cluster correlation coefficients were estimated for descriptive outcomes and for associations between outcomes and predictors and were compared across two independent samples of GPs drawn three years apart. Results Between April 1999 and March 2000, a random sample of 1,047 Australian general practitioners recorded details of 104,700 patient encounters. Intra-cluster correlation coefficients for patient demographics ranged from 0.055 for patient sex to 0.451 for language spoken at home. Intra-cluster correlations for morbidity variables ranged from 0.005 for the management of eye problems to 0.059 for management of psychological problems. Intra-cluster correlation for the association between two variables was smaller than the descriptive intra-cluster correlation of each variable. When compared with the April 2002 to March 2003 sample (1,008 GPs) the estimated intra-cluster correlation coefficients were found to be consistent across samples. Conclusions The demonstrated precision and reliability of the estimated intra-cluster correlations indicate that these coefficients will be useful for calculating sample sizes in future general practice surveys that use the GP as the primary sampling unit. PMID:15613248

  19. Explanations for Contempt Expressed Towards Old People.

    ERIC Educational Resources Information Center

    Maxwell, Eleanor Krassen; Maxwell, Robert J.

    The issue of contempt expressed towards the aged was examined from a cross-cultural perspective. Eight reasons for expressions of contempt emerged from a study of 95 societies drawn from the Standard Cross-Cultural Sample, and were treated as independent variables, with the overall level of contempt as the dependent variable, in a application of…

  20. Children's Motivation in Elementary Physical Education: A Longitudinal Study

    ERIC Educational Resources Information Center

    Xiang, Ping; McBride, Ron; Guan, Jianmin

    2004-01-01

    The present study examined relationships among variables drawn from achievement goal theory and the expectancy-value model of achievement choice as well as mean level changes of these variables over time in elementary physical education. Participants (N = 207) completed questionnaires over a 2-year period: once while in the second and fourth…

  1. Characterizing the Optical Variability of Bright Blazars: Variability-Based Selection of Fermi Active Galactic Nuclei

    DTIC Science & Technology

    2012-11-20

    10′. We do not apply cosmological redshift corrections here for blazar selection. Similar to the conclusions drawn from Figure 4, there is clear...effects. For example, the observed blazar characteristic damping timescale τblz,obs (after correcting for cosmological redshift) should be shortened in

  2. On the Misconception of Multicollinearity in Detection of Moderating Effects: Multicollinearity Is Not Always Detrimental

    ERIC Educational Resources Information Center

    Shieh, Gwowen

    2010-01-01

    Due to its extensive applicability and computational ease, moderated multiple regression (MMR) has been widely employed to analyze interaction effects between 2 continuous predictor variables. Accordingly, considerable attention has been drawn toward the supposed multicollinearity problem between predictor variables and their cross-product term.…

  3. Self-Regulated Learning and Ethnic/Racial Variables: Predicting Minority First-Generation College Students' Persistence

    ERIC Educational Resources Information Center

    Moore, John S., III.

    2013-01-01

    The purpose of this study was to investigate how self-regulated learning and ethnic/racial variables predict minority first-generation college student persistence and related constructs. Participants were drawn nationally from the U.S. Department of Education funded TRiO Student Support Services Programs. Additional participants from the Talent…

  4. Population density approach for discrete mRNA distributions in generalized switching models for stochastic gene expression.

    PubMed

    Stinchcombe, Adam R; Peskin, Charles S; Tranchina, Daniel

    2012-06-01

    We present a generalization of a population density approach for modeling and analysis of stochastic gene expression. In the model, the gene of interest fluctuates stochastically between an inactive state, in which transcription cannot occur, and an active state, in which discrete transcription events occur; and the individual mRNA molecules are degraded stochastically in an independent manner. This sort of model in simplest form with exponential dwell times has been used to explain experimental estimates of the discrete distribution of random mRNA copy number. In our generalization, the random dwell times in the inactive and active states, T_{0} and T_{1}, respectively, are independent random variables drawn from any specified distributions. Consequently, the probability per unit time of switching out of a state depends on the time since entering that state. Our method exploits a connection between the fully discrete random process and a related continuous process. We present numerical methods for computing steady-state mRNA distributions and an analytical derivation of the mRNA autocovariance function. We find that empirical estimates of the steady-state mRNA probability mass function from Monte Carlo simulations of laboratory data do not allow one to distinguish between underlying models with exponential and nonexponential dwell times in some relevant parameter regimes. However, in these parameter regimes and where the autocovariance function has negative lobes, the autocovariance function disambiguates the two types of models. Our results strongly suggest that temporal data beyond the autocovariance function is required in general to characterize gene switching.

  5. Generating variable and random schedules of reinforcement using Microsoft Excel macros.

    PubMed

    Bancroft, Stacie L; Bourret, Jason C

    2008-01-01

    Variable reinforcement schedules are used to arrange the availability of reinforcement following varying response ratios or intervals of time. Random reinforcement schedules are subtypes of variable reinforcement schedules that can be used to arrange the availability of reinforcement at a constant probability across number of responses or time. Generating schedule values for variable and random reinforcement schedules can be difficult. The present article describes the steps necessary to write macros in Microsoft Excel that will generate variable-ratio, variable-interval, variable-time, random-ratio, random-interval, and random-time reinforcement schedule values.

  6. Statistical optics

    NASA Astrophysics Data System (ADS)

    Goodman, J. W.

    This book is based on the thesis that some training in the area of statistical optics should be included as a standard part of any advanced optics curriculum. Random variables are discussed, taking into account definitions of probability and random variables, distribution functions and density functions, an extension to two or more random variables, statistical averages, transformations of random variables, sums of real random variables, Gaussian random variables, complex-valued random variables, and random phasor sums. Other subjects examined are related to random processes, some first-order properties of light waves, the coherence of optical waves, some problems involving high-order coherence, effects of partial coherence on imaging systems, imaging in the presence of randomly inhomogeneous media, and fundamental limits in photoelectric detection of light. Attention is given to deterministic versus statistical phenomena and models, the Fourier transform, and the fourth-order moment of the spectrum of a detected speckle image.

  7. Certain Characteristics of iSchools Compared to Other LIS Programs

    ERIC Educational Resources Information Center

    Wedgeworth, Robert

    2013-01-01

    This dissertation compares 17 iSchools and 36 other LIS schools that offer the ALA-accredited Master's degree program according to certain characteristics. The study compiles quantitative and qualitative data on 32 variables and sub-variables drawn from the schools' web sites, ALISE 2010 Statistical Report, and Elsevier's SCOPUS…

  8. Mental Health Correlates of Post Disaster Increases in Alcohol and Cigarette Smoking: A Vietnamese Study

    ERIC Educational Resources Information Center

    Ritter, Juliana D.; McCauley, Jenna L.; Amstadter, Ananda B.; Richardson, Lisa; Kilpatrick, Dean; Tran, Trinh L.; Trung, Lam T.; Tam, Nguyen T.; Tuan, Tran; Buoi, La Thi; Ha, Tran Thu; Thach, Tran D.; Acierno, Ron

    2011-01-01

    Previous research in US populations has found associations between disaster-related variables, psychological variables, and post-disaster increases in smoking and alcohol use. To date, no research has examined this association in an international population of disaster exposed individuals. Data used in this study were drawn from a larger study…

  9. Convergence to equilibrium under a random Hamiltonian.

    PubMed

    Brandão, Fernando G S L; Ćwikliński, Piotr; Horodecki, Michał; Horodecki, Paweł; Korbicz, Jarosław K; Mozrzymas, Marek

    2012-09-01

    We analyze equilibration times of subsystems of a larger system under a random total Hamiltonian, in which the basis of the Hamiltonian is drawn from the Haar measure. We obtain that the time of equilibration is of the order of the inverse of the arithmetic average of the Bohr frequencies. To compute the average over a random basis, we compute the inverse of a matrix of overlaps of operators which permute four systems. We first obtain results on such a matrix for a representation of an arbitrary finite group and then apply it to the particular representation of the permutation group under consideration.

  10. Convergence to equilibrium under a random Hamiltonian

    NASA Astrophysics Data System (ADS)

    Brandão, Fernando G. S. L.; Ćwikliński, Piotr; Horodecki, Michał; Horodecki, Paweł; Korbicz, Jarosław K.; Mozrzymas, Marek

    2012-09-01

    We analyze equilibration times of subsystems of a larger system under a random total Hamiltonian, in which the basis of the Hamiltonian is drawn from the Haar measure. We obtain that the time of equilibration is of the order of the inverse of the arithmetic average of the Bohr frequencies. To compute the average over a random basis, we compute the inverse of a matrix of overlaps of operators which permute four systems. We first obtain results on such a matrix for a representation of an arbitrary finite group and then apply it to the particular representation of the permutation group under consideration.

  11. The propensity to adopt evidence-based practice among physical therapists

    PubMed Central

    Bridges, Patricia H; Bierema, Laura L; Valentine, Thomas

    2007-01-01

    Background Many authors, as well as the American Physical Therapy Association, advocate that physical therapists adopt practice patterns based on research evidence, known as evidence-based practice (EBP). At the same time, physical therapists should be capable of integrating EBP within the day-to-day practice of physical therapy. The purpose of this study was to determine the extent to which personal characteristics and the characteristics of the social system in the workplace influence the propensity of physical therapists to adopt EBP. Methods The study used a 69 item mailed self-completion questionnaire. The questionnaire had four major sections. The first three sections were each drawn from a different theoretical framework and from different authors' work. The instrument was developed to capture the propensity of physical therapists to adopt EBP, characteristics of the social system in the workplace of physical therapists, personal characteristics of physical therapists, and selected demographic variables of physical therapists. The eligible population consisted of 3,897 physical therapists licensed by the state of Georgia in the United States of America. A random sample of 1320 potential participants was drawn. Results 939 questionnaires were returned for a response rate of 73%. 831 of the participants' questionnaires were useable and became the basis for the study. There was a moderate association between desire for learning (r = .36, r2 = .13), highest degree held (r = .29, r2 = .08), practicality (r = .27, r2 = .07) and nonconformity (r = .24, r2 = .06) and the propensity to adopt EBP. A negative correlation was found between age, years licensed and percentage of time in direct patient care. The findings demonstrated that the best three variables for predicting the propensity to adopt EBP in physical therapy were: desire for learning, highest degree held, and practicality. Conclusion The study confirms there is no single factor to facilitate research evidence into day-to-day practice. Multiple practice change strategies will be needed to facilitate change in practice. PMID:17615076

  12. Generating Variable and Random Schedules of Reinforcement Using Microsoft Excel Macros

    PubMed Central

    Bancroft, Stacie L; Bourret, Jason C

    2008-01-01

    Variable reinforcement schedules are used to arrange the availability of reinforcement following varying response ratios or intervals of time. Random reinforcement schedules are subtypes of variable reinforcement schedules that can be used to arrange the availability of reinforcement at a constant probability across number of responses or time. Generating schedule values for variable and random reinforcement schedules can be difficult. The present article describes the steps necessary to write macros in Microsoft Excel that will generate variable-ratio, variable-interval, variable-time, random-ratio, random-interval, and random-time reinforcement schedule values. PMID:18595286

  13. A Population of Assessment Tasks

    ERIC Educational Resources Information Center

    Daro, Phil; Burkhardt, Hugh

    2012-01-01

    We propose the development of a "population" of high-quality assessment tasks that cover the performance goals set out in the "Common Core State Standards for Mathematics." The population will be published. Tests are drawn from this population as a structured random sample guided by a "balancing algorithm."

  14. Depression in type 2 diabetes mellitus: prevalence, impact, and treatment.

    PubMed

    Semenkovich, Katherine; Brown, Miriam E; Svrakic, Dragan M; Lustman, Patrick J

    2015-04-01

    Clinically significant depression is present in one of every four people with type 2 diabetes mellitus (T2DM). Depression increases the risk of the development of T2DM and the subsequent risks of hyperglycemia, insulin resistance, and micro- and macrovascular complications. Conversely, a diagnosis of T2DM increases the risk of incident depression and can contribute to a more severe course of depression. This linkage reflects a shared etiology consisting of complex bidirectional interactions among multiple variables, a process that may include autonomic and neurohormonal dysregulation, weight gain, inflammation, and hippocampal structural alterations. Two recent meta-analyses of randomized controlled depression treatment trials in patients with T2DM concluded that psychotherapy and antidepressant medication (ADM) were each moderately effective for depression and that cognitive behavior therapy (CBT) had beneficial effects on glycemic control. However, the number of studies (and patients exposed to randomized treatment) included in these analyses is extremely small and limits the certainty of conclusions that can be drawn from the data. Ultimately, there is no escaping the paucity of the evidence base and the need for additional controlled trials that specifically address depression management in T2DM. Future trials should determine both the effects of treatment and the change in depression during treatment on measures of mood, glycemic control, and medical outcome.

  15. The Value of Information in Distributed Decision Networks

    DTIC Science & Technology

    2016-03-04

    formulation, and then we describe the various results at- tained. 1 Mathematical description of Distributed Decision Network un- der Information...Constraints We now define a mathematical framework for networks. Let G = (V,E) be an undirected random network (graph) drawn from a known distribution pG, 1

  16. Family socialization of adolescent's self-reported cigarette use: the role of parents' history of regular smoking and parenting style.

    PubMed

    Foster, Sarah E; Jones, Deborah J; Olson, Ardis L; Forehand, Rex; Gaffney, Cecelia A; Zens, Michael S; Bau, J J

    2007-05-01

    To examine the main and interactive effects of parental history of regular cigarette smoking and parenting style on adolescent self-reported cigarette use. Predictors of adolescent self-reported cigarette use, including parents' history of regular cigarette smoking and two dimensions of parenting behavior, were analyzed in a sample of 934 predominately Caucasian (96.3%) parent-adolescent dyads. Families were drawn from the control group of a randomized control trial aimed at preventing adolescent substance use. In addition to the main effects of parents' history of regular smoking and parental warmth, logistic regression analysis revealed that the interaction of these two variables was associated with adolescent self-reported cigarette use. Parental warmth was associated with a decreased likelihood of the adolescent ever having smoked a cigarette; however, this was true only if neither parent had a history of regular cigarette smoking. Findings suggest that adolescent smoking prevention programs may be more efficacious if they address both parental history of regular smoking and parenting behavior.

  17. Does grandchild care influence grandparents' self-rated health? Evidence from a fixed effects approach.

    PubMed

    Ates, Merih

    2017-10-01

    The present study aims to identify, whether and how supplementary grandchild care is causally related to grandparents' self-rated health (SRH). Based on longitudinal data drawn from the German Aging Survey (DEAS; 2008-2014), I compare the results of pooled OLS, pooled OLS with lagged dependant variables (POLS-LD), random and fixed effects (RE, FE) panel regression. The results show that there is a positive but small association between supplementary grandchild care and SRH in POLS, POLS-LD, and RE models. However, the fixed effects model shows that the intrapersonal change in grandchild care does not cause a change in grandparents' SRH. The FE findings indicate that supplementary grandchild care in Germany does not have a causal impact on grandparents' SRH, suggesting that models with between-variation components overestimate the influence of grandchild care on grandparents' health because they do not control for unobserved (time-constant) heterogeneity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Empirical microeconomics action functionals

    NASA Astrophysics Data System (ADS)

    Baaquie, Belal E.; Du, Xin; Tanputraman, Winson

    2015-06-01

    A statistical generalization of microeconomics has been made in Baaquie (2013), where the market price of every traded commodity, at each instant of time, is considered to be an independent random variable. The dynamics of commodity market prices is modeled by an action functional-and the focus of this paper is to empirically determine the action functionals for different commodities. The correlation functions of the model are defined using a Feynman path integral. The model is calibrated using the unequal time correlation of the market commodity prices as well as their cubic and quartic moments using a perturbation expansion. The consistency of the perturbation expansion is verified by a numerical evaluation of the path integral. Nine commodities drawn from the energy, metal and grain sectors are studied and their market behavior is described by the model to an accuracy of over 90% using only six parameters. The paper empirically establishes the existence of the action functional for commodity prices that was postulated to exist in Baaquie (2013).

  19. Adolescents and alcohol: an explorative audience segmentation analysis

    PubMed Central

    2012-01-01

    Background So far, audience segmentation of adolescents with respect to alcohol has been carried out mainly on the basis of socio-demographic characteristics. In this study we examined whether it is possible to segment adolescents according to their values and attitudes towards alcohol to use as guidance for prevention programmes. Methods A random sample of 7,000 adolescents aged 12 to 18 was drawn from the Municipal Basic Administration (MBA) of 29 Local Authorities in the province North-Brabant in the Netherlands. By means of an online questionnaire data were gathered on values and attitudes towards alcohol, alcohol consumption and socio-demographic characteristics. Results We were able to distinguish a total of five segments on the basis of five attitude factors. Moreover, the five segments also differed in drinking behavior independently of socio-demographic variables. Conclusions Our investigation was a first step in the search for possibilities of segmenting by factors other than socio-demographic characteristics. Further research is necessary in order to understand these results for alcohol prevention policy in concrete terms. PMID:22950946

  20. Equitability of Treatment in Army Judicial Proceedings (ETAJUP)

    DTIC Science & Technology

    1993-12-01

    difference associated with Black offenders has a MIN of -0.8 percent at the "More than 75%" in charges level. (c) Comment on Factor. In general, most cases...system. The analysis seeks to identify the most significant variables drawn from court-martial case records which distinguish membership in these groups...means and variances of the two classes are computed for each variable. The variable with the most statistically significant 1-test is selected to

  1. Agreement of parents and children on characteristics of pediatric headache, other pains, somatic symptoms, and depressive symptoms in an epidemiologic study.

    PubMed

    Kröner-Herwig, Birgit; Morris, Lisette; Heinrich, Marion; Gassmann, Jennifer; Vath, Nuria

    2009-01-01

    The objective of the present study was to assess the concordance between parent and child report regarding different domains of pediatric health, headache in particular. In addition, the influence of potential moderator variables on the agreement between parents and children was examined. In an epidemiologic study on a randomly drawn sample of households with at least 1 child in the family between 7 and 14 years of age (community registries), various pediatric health disturbances (headache, other pains, somatic symptoms, and depression/anxiety) were assessed via both child (from the age of 9 y on) and parent report (n=3461). A relatively high parent-child agreement (sigmaM=0.61) was found regarding the variable headache frequency, whereas consensus regarding other pains was, for the most part, markedly lower. The lowest agreement (sigmaM=0.27) was found for depression/anxiety symptoms. A moderator analysis (with age, sex, and parental headache) between child and parent failed to reveal significant differences regarding the degree of agreement between the 2 data sources. Children reported more frequent and more severe symptoms in all health domains. The examined potential moderator variables did not elucidate processes underlying the differences in child and parent agreement. There is no convincing evidence that the children's appraisal is less valid than their parents'. In summary, parents' reports cannot be viewed as a substitute for children's reports in pediatric pain and health assessment. Instead, each perspective represents a unique subjective reality and as such, both are of importance for research on pediatric pain and other health variables.

  2. From micro-correlations to macro-correlations

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

    Eliazar, Iddo, E-mail: iddo.eliazar@intel.com

    2016-11-15

    Random vectors with a symmetric correlation structure share a common value of pair-wise correlation between their different components. The symmetric correlation structure appears in a multitude of settings, e.g. mixture models. In a mixture model the components of the random vector are drawn independently from a general probability distribution that is determined by an underlying parameter, and the parameter itself is randomized. In this paper we study the overall correlation of high-dimensional random vectors with a symmetric correlation structure. Considering such a random vector, and terming its pair-wise correlation “micro-correlation”, we use an asymptotic analysis to derive the random vector’smore » “macro-correlation” : a score that takes values in the unit interval, and that quantifies the random vector’s overall correlation. The method of obtaining macro-correlations from micro-correlations is then applied to a diverse collection of frameworks that demonstrate the method’s wide applicability.« less

  3. Reliability of the Cardiff Test of basic life support and automated external defibrillation version 3.1.

    PubMed

    Whitfield, Richard H; Newcombe, Robert G; Woollard, Malcolm

    2003-12-01

    The introduction of the European Resuscitation Guidelines (2000) for cardiopulmonary resuscitation (CPR) and automated external defibrillation (AED) prompted the development of an up-to-date and reliable method of assessing the quality of performance of CPR in combination with the use of an AED. The Cardiff Test of basic life support (BLS) and AED version 3.1 was developed to meet this need and uses standardised checklists to retrospectively evaluate performance from analyses of video recordings and data drawn from a laptop computer attached to a training manikin. This paper reports the inter- and intra-observer reliability of this test. Data used to assess reliability were obtained from an investigation of CPR and AED skill acquisition in a lay responder AED training programme. Six observers were recruited to evaluate performance in 33 data sets, repeating their evaluation after a minimum interval of 3 weeks. More than 70% of the 42 variables considered in this study had a kappa score of 0.70 or above for inter-observer reliability or were drawn from computer data and therefore not subject to evaluator variability. 85% of the 42 variables had kappa scores for intra-observer reliability of 0.70 or above or were drawn from computer data. The standard deviations for inter- and intra-observer measures of time to first shock were 11.6 and 7.7 s, respectively. The inter- and intra-observer reliability for the majority of the variables in the Cardiff Test of BLS and AED version 3.1 is satisfactory. However, reliability is less acceptable with respect to shaking when checking for responsiveness, initial check/clearing of the airway, checks for signs of circulation, time to first shock and performance of interventions in the correct sequence. Further research is required to determine if modifications to the method of assessing these variables can increase reliability.

  4. Effects of endovascular cooling on infarct size in ST-segment elevation myocardial infarction: A patient-level pooled analysis from randomized trials.

    PubMed

    Dae, Michael; O'Neill, William; Grines, Cindy; Dixon, Simon; Erlinge, David; Noc, Marko; Holzer, Michael; Dee, Anne

    2018-06-01

    This study sought to examine the relationship between temperature at reperfusion and infarct size. Hypothermia consistently reduces infarct size when administered prior to reperfusion in animal studies, however, clinical results have been inconsistent. We performed a patient-level pooled analysis from six randomized control trials of endovascular cooling during primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) in 629 patients in which infarct size was assessed within 1 month after randomization by either single-photon emission computed tomography (SPECT) or cardiac magnetic resonance imaging (cMR). In anterior infarct patients, after controlling for variability between studies, mean infarct size in controls was 21.3 (95%CI 17.4-25.3) and in patients with hypothermia <35°C it was 14.8 (95%CI 10.1-19.6), which was a statistically significant absolute reduction of 6.5%, or a 30% relative reduction in infarct size (P = 0.03). There was no significant difference in infarct size in anterior ≥35°C, or inferior infarct patients. There was no difference in the incidence of death, ventricular arrhythmias, or re-infarction due to stent thrombosis between hypothermia and control patients. The present study, drawn from a patient-level pooled analysis of six randomized trials of endovascular cooling during primary PCI in STEMI, showed a significant reduction in infarct size in patients with anterior STEMI who were cooled to <35°C at the time of reperfusion. The results support the need for trials in patients with anterior STEMI using more powerful cooling devices to optimize the delivery of hypothermia prior to reperfusion. © 2017 The Authors. Journal of Interventional Cardiology Published by Wiley Periodicals, Inc.

  5. Relative Carnitine Deficiency in Autism

    ERIC Educational Resources Information Center

    Filipek, Pauline A.; Juranek, Jenifer; Nguyen, Minh T.; Cummings, Christa; Gargus, J. Jay

    2004-01-01

    A random retrospective chart review was conducted to document serum carnitine levels on 100 children with autism. Concurrently drawn serum pyruvate, lactate, ammonia, and alanine levels were also available in many of these children. Values of free and total carnitine ([rho] less than 0.001), and pyruvate ([rho]=0.006) were significantly reduced…

  6. Apprehension and Effective Writing in the Principalship.

    ERIC Educational Resources Information Center

    Podsen, India J.

    1991-01-01

    A random sample of 305 principals was drawn from the membership roosters of 4 Principal Centers. Responses from 100 principals (33 percent) show that there is a relationship between writing apprehension level on performance of job writing skills. Advises school administrators to take courses in current written communication practices. (six…

  7. Correcting Poor Posture without Awareness or Willpower

    ERIC Educational Resources Information Center

    Wernik, Uri

    2012-01-01

    In this article, a new technique for correcting poor posture is presented. Rather than intentionally increasing awareness or mobilizing willpower to correct posture, this approach offers a game using randomly drawn cards with easy daily assignments. A case using the technique is presented to emphasize the subjective experience of living with poor…

  8. Relationship of Study Habits with Mathematics Achievement

    ERIC Educational Resources Information Center

    Odiri, Onoshakpokaiye E.

    2015-01-01

    The study examined the relationship of study habits of students and their achievement in mathematics. The method used for the study was correlation design. A sample of 500 students were randomly selected from 25 public secondary schools in Delta Central Senatorial District, Delta State, Nigeria. Questionnaires were drawn to gather data on…

  9. 40 CFR 204.51 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... tests. (m) Test sample means the collection of compressors from the same category or configuration which is randomly drawn from the batch sample and which will receive emissions tests. (n) Batch size means... category or configuration in a batch. (o) Test sample size means the number of compressors of the same...

  10. The Causal Relationship of Organizational Performance of Thailand Private Higher Education Institutions

    ERIC Educational Resources Information Center

    Mahasinpaisan, Tippaporn

    2011-01-01

    The purpose of this study was to propose causal model of the relationship among transformational leadership, organizational culture, knowledge management, and organizational performance. A sample of 389 was randomly drawn from instructors of private higher education institutions under the Office of the Higher Education Commission. Data were…

  11. School Counselors' Perceptions of Biracial Students' Functioning

    ERIC Educational Resources Information Center

    Kindaichi, Mai Margaret

    2010-01-01

    The number of biracial school-aged youth has continued to increase dramatically (Jones & Smith, 2001), and has drawn timely attention to the extent to which practicing school counselors address biracial youths' concerns in a culturally competent manner. This study examined the perceptions of a nationally-based random sample of 203 White school…

  12. Women Secondary Principals in Texas 1998 and 2011: Movement toward Equity

    ERIC Educational Resources Information Center

    Marczynski, Jean C.; Gates, Gordon S.

    2013-01-01

    Purpose: The purpose of this paper is to analyze data gathered in 1998 and 2011 from representative samples of women secondary school principals in Texas to identify differences in personal, professional, leadership, and school characteristics. Design/methodology/approach: Two proportionate, random samples were drawn of women secondary principals…

  13. A national mass media smoking cessation campaign: effects by race/ethnicity and education.

    PubMed

    Vallone, Donna M; Niederdeppe, Jeff; Richardson, Amanda Kalaydjian; Patwardhan, Pallavi; Niaura, Raymond; Cullen, Jennifer

    2011-01-01

    To assess the effectiveness of a large-scale, national smoking cessation media campaign, the EX campaign, across racial/ethnic and educational subgroups. A longitudinal random-digit-dial panel study conducted prior to and 6 months following the national launch of the campaign. The sample was drawn from eight designated media markets in the United States. The baseline survey was conducted on 5616 current smokers, aged 18 to 49 years, and 4067 (73% follow-up response rate) were resurveyed at the 6-month follow-up. The primary independent variable is confirmed awareness of the campaign advertising, and the outcome variables are follow-up cessation-related cognitions index score and quit attempts. Multivariable logistic and linear regression analyses were conducted within racial/ethnic and educational strata to assess the strength of association between confirmed awareness of campaign advertising and cessation-related outcomes. Confirmed awareness of campaign advertising increased favorable cessation-related cognitions among Hispanics and quit attempts among non-Hispanic blacks, and increased favorable cessation-related cognitions and quit attempts among smokers with less than a high school education. These results suggest that the EX campaign may be effective in promoting cessation-related cognitions and behaviors among minority and disadvantaged smokers who experience a disproportionate burden of tobacco-related illness and mortality.

  14. A systematic overview of radiation therapy effects in oesophageal cancer.

    PubMed

    Ask, Anders; Albertsson, Maria; Järhult, Johannes; Cavallin-Ståhl, Eva

    2003-01-01

    A systematic review of radiation therapy trials in several tumour types was performed by The Swedish Council of Technology Assessment in Health Care (SBU). The procedures for evaluation of the scientific literature are described separately (Acta Oncol 2003; 42: 357-365). This synthesis of the literature on radiation therapy for oesophageal cancer is based on data from 42 randomized trials and 2 meta-analyses. A total of 44 scientific articles are included, involving 5 772 patients. The conclusions reached can be summarized as follows: There is fairly strong evidence that preoperative radiotherapy does not improve the survival in patients with potentially resectable oesophageal cancer. There is moderate evidence that preoperative chemo-radiotherapy has no beneficial impact on the survival of patients with potentially resectable oesophageal cancer. There is no scientific evidence that postoperative radiotherapy improves survival in patients with resectable oesophageal cancer. The documentation is, however, poor, consisting of only three randomized trials. There is fairly strong evidence that concomitant (but not sequential) chemo-radiotherapy gives significantly better survival rate than radiotherapy alone in inoperable oesophageal cancer. The results of the reported clinical trials are, however, conflicting, and no solid conclusion can be drawn. Hyperfractionated radiotherapy has been compared with conventionally fractionated radiotherapy in two randomized studies with conflicting results and no firm conclusion can be drawn.

  15. An efficient algorithm for generating random number pairs drawn from a bivariate normal distribution

    NASA Technical Reports Server (NTRS)

    Campbell, C. W.

    1983-01-01

    An efficient algorithm for generating random number pairs from a bivariate normal distribution was developed. Any desired value of the two means, two standard deviations, and correlation coefficient can be selected. Theoretically the technique is exact and in practice its accuracy is limited only by the quality of the uniform distribution random number generator, inaccuracies in computer function evaluation, and arithmetic. A FORTRAN routine was written to check the algorithm and good accuracy was obtained. Some small errors in the correlation coefficient were observed to vary in a surprisingly regular manner. A simple model was developed which explained the qualities aspects of the errors.

  16. The Direct and Indirect Effects of Paliperidone Extended-release on Depressive Symptoms in Schizoaffective Disorder: A Path Analysis.

    PubMed

    Turkoz, Ibrahim; Fu, Dong-Jing; Bossie, Cynthia A; Alphs, Larry

    2015-01-01

    This analysis evaluates improvement in symptoms of depression in patients with schizoaffective disorder administered oral paliperidone extended-release by accounting for the magnitude of direct and indirect (changes in negative and positive symptoms and worsening of extrapyramidal symptoms) treatment effects on depressive symptoms. Data for this post hoc analysis were drawn from two six-week, randomized, placebo-controlled studies of paliperidone extended-release versus placebo in adult subjects with schizoaffective disorder (N=614; NCT00412373, NCT00397033). Subjects with baseline 17-item Hamilton Rating Scale for Depression scores of 16 or greater were included. Structural equation models (path analyses) were used to separate total effects into direct and indirect effects on depressive symptoms. Change from baseline in 17-item Hamilton Rating Scale for Depression score at the Week 6 end point was the dependent variable; changes in Positive and Negative Syndrome Scale positive and negative factors and Simpson-Angus Scale (to evaluate extrapyramidal symptoms) scores were independent variables. At baseline, 332 of 614 (54.1%) subjects had a 17-item Hamilton Rating Scale for Depression score of 16 or greater. Path analysis determined that up to 26.4 percent of the paliperidone extended-release versus placebo effect on depressive symptoms may be attributed to a direct treatment effect, and 45.8 percent and 28.4 percent were mediated indirectly through improvements on positive and negative symptoms, respectively. No effects were identified as mediated through extrapyramidal symptoms changes (-0.7%). RESULTS of this analysis suggest that paliperidone's effect on depressive symptoms in subjects with schizoaffective disorder participating in two six-week, randomized, placebo-controlled studies is mediated through indirect effects (e.g., positive and negative symptom changes) and a direct treatment effect.

  17. Among Patients Undergoing Ablative Treatment for Oral Cancer, Does the Provision of Oral Rehabilitation Improve the Quality of Life? A Review of the Current Literature.

    PubMed

    Petrosyan, Vahe; Ball, Dimity; Harrison, Rebecca; Ameerally, Phillip

    2016-05-01

    The impact of oral cancer and its treatment is well documented; therefore, oral rehabilitation (OH; eg, with prosthetics, osseointegrated implants, etc) can be indicated to restore some level of form, function, and well-being. The purpose of this study was to review the current literature and evaluate the impact of OH on quality of life (QoL) after ablative surgery. A systematic literature search was conducted using EMBASE, MEDLINE, and PsychINFO. The study population was composed of all articles published from 2000 to 2015. To be included, studies had to use validated, specific head and neck QoL measurements (European Organization for Research and Treatment of Cancer QoL Head and Neck Module or University of Washington QoL Questionnaire). Only 8 articles met these inclusion criteria. In this review, OH was the primary predictor variable and QoL was the primary outcome variable. The 8 articles reviewed used a range of designs, including 1 randomized controlled trial, 3 prospective cohort studies, 3 case series, and 1 single-measurement cross-sectional descriptive study. Sample sizes were small (n = 26 to 102), and there was limited randomization and control of intervention and comparator groups. The overall level of evidence was weak. All studies showed a link between OH and QoL, but the results varied in significance (P < .01 to P = .95). Overall, there appears to be improvement in QoL to varying degrees after OH. However, a more systematic use of QoL measurements is needed before any definitive conclusions can be drawn. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  18. HDMR methods to assess reliability in slope stability analyses

    NASA Astrophysics Data System (ADS)

    Kozubal, Janusz; Pula, Wojciech; Vessia, Giovanna

    2014-05-01

    Stability analyses of complex rock-soil deposits shall be tackled considering the complex structure of discontinuities within rock mass and embedded soil layers. These materials are characterized by a high variability in physical and mechanical properties. Thus, to calculate the slope safety factor in stability analyses two issues must be taken into account: 1) the uncertainties related to structural setting of the rock-slope mass and 2) the variability in mechanical properties of soils and rocks. High Dimensional Model Representation (HDMR) (Chowdhury et al. 2009; Chowdhury and Rao 2010) can be used to carry out the reliability index within complex rock-soil slopes when numerous random variables with high coefficient of variations are considered. HDMR implements the inverse reliability analysis, meaning that the unknown design parameters are sought provided that prescribed reliability index values are attained. Such approach uses implicit response functions according to the Response Surface Method (RSM). The simple RSM can be efficiently applied when less than four random variables are considered; as the number of variables increases, the efficiency in reliability index estimation decreases due to the great amount of calculations. Therefore, HDMR method is used to improve the computational accuracy. In this study, the sliding mechanism in Polish Flysch Carpathian Mountains have been studied by means of HDMR. The Southern part of Poland where Carpathian Mountains are placed is characterized by a rather complicated sedimentary pattern of flysh rocky-soil deposits that can be simplified into three main categories: (1) normal flysch, consisting of adjacent sandstone and shale beds of approximately equal thickness, (2) shale flysch, where shale beds are thicker than adjacent sandstone beds, and (3) sandstone flysch, where the opposite holds. Landslides occur in all flysch deposit types thus some configurations of possible unstable settings (within fractured rocky-soil masses) resulting in sliding mechanisms have been investigated in this study. The reliability indices values drawn from the HDRM method have been compared with conventional approaches as neural networks: the efficiency of HDRM is shown in the case studied. References Chowdhury R., Rao B.N. and Prasad A.M. 2009. High-dimensional model representation for structural reliability analysis. Commun. Numer. Meth. Engng, 25: 301-337. Chowdhury R. and Rao B. 2010. Probabilistic Stability Assessment of Slopes Using High Dimensional Model Representation. Computers and Geotechnics, 37: 876-884.

  19. Describing the Elephant: Structure and Function in Multivariate Data.

    ERIC Educational Resources Information Center

    McDonald, Roderick P.

    1986-01-01

    There is a unity underlying the diversity of models for the analysis of multivariate data. Essentially, they constitute a family of models, most generally nonlinear, for structural/functional relations between variables drawn from a behavior domain. (Author)

  20. Psycho-Social Factors Causing Stress: A Study of Teacher Educators

    ERIC Educational Resources Information Center

    Jain, Geetika; Tyagi, Harish Kumar; Kumar, Anil

    2015-01-01

    Purpose: The present investigation was planned to determine the influence of type of personality, gender, age, qualification and experience causing stress among teacher educators at work. Method: A sample of 100 subjects from male and female teachers teaching in teacher training colleges, Delhi, India was drawn randomly. The data was collected by…

  1. Collaborative Job Training in Rural Areas

    ERIC Educational Resources Information Center

    Green, Gary Paul; Galetto, Valeria; Haines, Anna

    2003-01-01

    We examine collaborative efforts by employers to provide job training in rural areas and assess how this collaboration affects the willingness of employers to train workers. Data are drawn from a telephone survey conducted in 2001 of a stratified random sample of 1,590 nonmetropolitan firms in the U.S. The literature on job training suggests that…

  2. Family Conflict as a Mediator of Caregiver Strain

    ERIC Educational Resources Information Center

    Scharlach, Andrew; Li, Wei; Dalvi, Tapashi B.

    2006-01-01

    The present study used structural equation modeling to examine the potential mediating effect of family conflict on caregiver strain in a randomly drawn household sample of 650 adults with primary care responsibility for an adult age 50 or older with a mental disability. Caregiver strain was directly influenced by the conflict, disagreements, and…

  3. Exceptional Children and Microcomputers, A Survey of Public School Applications.

    ERIC Educational Resources Information Center

    Crowner, T. Timothy

    Telephone interviews on the use of microcomputers in special education were administered to personnel in 25 districts (drawn from a random sample of the largest school districts in the United States) on the following topics: coordination of microcomputers; numbers of microcomputers owned and used; pragmatic uses; funding; brands used; selection,…

  4. Literacy, Information and Communication Technology as Tools for Empowerment of Inmates

    ERIC Educational Resources Information Center

    Joseph, Tenibiaje Dele

    2012-01-01

    The study investigated the present position of literacy, information and communication technology (ICT) in prisons by examining the perception of inmates. The study adopted a descriptive survey using structured questionnaire and observation guides on a randomly and purposively drawn sample of 664 inmates out of a population of 47,628 inmates…

  5. MPA and CPM Curriculum: An Analysis of the Views of Public Administrators.

    ERIC Educational Resources Information Center

    Rose, Bruce J.

    Views of state public administrators about management education and training needs were investigated, as were administrator views concerning short-term management development workshops. Data was drawn from responses to questionnaires mailed to 5,980 state administrators who were selected from a national survey and from random samples using lists…

  6. Evaluation of an Anger Therapy Intervention for Incarcerated Adult Males

    ERIC Educational Resources Information Center

    Vannoy, Steven D.; Hoyt, William T.

    2004-01-01

    An anger therapy intervention was developed for incarcerated adult males. The therapy was an extension of cognitive-behavioral approaches, incorporating principles and practices drawn from Buddhist psychology. Adult males from a Midwestern low-security prison were randomly assigned to either a treatment group (n= 16) or a waiting list control…

  7. Community of Inquiry Method and Language Skills Acquisition: Empirical Evidence

    ERIC Educational Resources Information Center

    Preece, Abdul Shakhour Duncan

    2015-01-01

    The study investigates the effectiveness of community of inquiry method in preparing students to develop listening and speaking skills in a sample of junior secondary school students in Borno state, Nigeria. A sample of 100 students in standard classes was drawn in one secondary school in Maiduguri metropolis through stratified random sampling…

  8. Home Education: Characteristics of Its Families and Schools.

    ERIC Educational Resources Information Center

    Gladin, Earl Wade

    This study of the characteristics of home schooling is based on returned questionnaires of 37 questions each, mailed to a random sample of 416 drawn from 6,850 families listed in the Bob Jones University Press home school mailing list. The 253 returned questionnaires, representing a 62% reponse, provided data on the characteristics of these…

  9. Examining iPod Use by Texas Agricultural Science and Technology Teachers

    ERIC Educational Resources Information Center

    Murphrey, Theresa Pesl; Miller, Kimberly A.; Roberts, T. Grady

    2009-01-01

    The purpose of this study was to establish baseline data regarding the adoption of iPods and similar technologies by agricultural science and technology teachers. The population consisted of all agricultural science and technology teachers in Texas. A sample of 310 was randomly drawn from the population. Study findings reveal that while…

  10. Drug Testing High School Athletes and the Fourth Amendment.

    ERIC Educational Resources Information Center

    Bjorklun, Eugene C.

    1993-01-01

    Examines recent court decisions regarding the legality of drug-testing programs aimed at student athletes. Concludes the drug-testing programs will be upheld if the program is narrowly drawn with regard to the student population; aims at limited and achievable goals; involves random selection of students for testing; and imposes penalties…

  11. An Investigation of the Difficulties Faced by EFL Undergraduates in Speaking Skills

    ERIC Educational Resources Information Center

    Al-Jamal, Dina A.; Al-Jamal, Ghadeer A.

    2014-01-01

    Since speaking well in English is crucial for English language literature undergraduates, the present study aimed at describing difficulties that may be encountered at an EFL setting. The sample was stratified random as drawn from six Jordanian public universities. Survey questionnaires as well as semi-structured interviews were constructed. 64…

  12. Altering Attitudes toward Suicide in an Abnormal Psychology Course.

    ERIC Educational Resources Information Center

    Domino, George

    1980-01-01

    The article describes a report stemming from the development and application of a Suicide Opinion Questionnaire (SOQ)--a 100 item attitudinal and factual instrument designed to cover a wide range of suicidal concerns. Subjects of the study were 17 college students drawn at random from 89 students enrolled in an abnormal psychology course. Results…

  13. INFERENCES DRAWN FROM A RISK ASSESSMENT COMPARED DIRECTLY TO A RANDOMIZED TRIAL OF A HOME DRINKING WATER INTERVENTION

    EPA Science Inventory

    Risk assessments and intervention trials have been used to inform the EPA on drinking water risks. Seldom are both methods used concurrently. Between 2001 and 2003, illness data from a trial were collected simultaneously with exposure data, providing a unique opportunity to com...

  14. Seven Elements Important to Successful Implementation of Early Literacy Intervention

    ERIC Educational Resources Information Center

    Foorman, Barbara; Dombek, Jennifer; Smith, Kevin

    2016-01-01

    The objective of this article is to describe seven elements important to successful implementation of early literacy intervention. The seven elements are drawn from research as well as from the authors' recent randomized controlled trial of effective early literacy interventions in kindergarten through second grade in 55 schools across Florida.…

  15. Assessing Students' Metacognitive Awareness of Learning Strategies among Secondary School Students in Edo State, Nigeria

    ERIC Educational Resources Information Center

    Okoza, Jolly; Aluede, Oyaziwo; Owens-Sogolo, Osasere

    2013-01-01

    This study examined metacognitive awareness of learning strategies among Secondary School Students in Edo State, Nigeria. The study was an exploratory one, which utilized descriptive statistics. A total number of 1200 students drawn through multistage proportionate random sampling technique participated in the study. The study found that secondary…

  16. Construct Equivalence of a National Certification Examination that Uses Dual Languages and Audio Assistance

    ERIC Educational Resources Information Center

    Wang, Shudong; Wang, Ning; Hoadley, David

    2007-01-01

    This study used confirmatory factor analysis (CFA) to examine the comparability of the National Nurse Aide Assessment Program (NNAAP[TM]) test scores across language and administration condition groups for calibration and validation samples that were randomly drawn from the same population. Fit statistics supported both the calibration and…

  17. An issue encountered in solving problems in electricity and magnetism: curvilinear coordinates

    NASA Astrophysics Data System (ADS)

    Gülçiçek, Çağlar; Damlı, Volkan

    2016-11-01

    In physics lectures on electromagnetic theory and mathematical methods, physics teacher candidates have some difficulties with curvilinear coordinate systems. According to our experience, based on both in-class interactions and teacher candidates’ answers in test papers, they do not seem to have understood the variables in curvilinear coordinate systems very well. For this reason, the problems that physics teacher candidates have with variables in curvilinear coordinate systems have been selected as a study subject. The aim of this study is to find the physics teacher candidates’ problems with determining the variables of drawn shapes, and problems with drawing shapes based on given variables in curvilinear coordinate systems. Two different assessment tests were used in the study to achieve this aim. The curvilinear coordinates drawing test (CCDrT) was used to discover their problems related to drawing shapes, and the curvilinear coordinates detection test (CCDeT) was used to find out about problems related to determining variables. According to the findings obtained from both tests, most physics teacher candidates have problems with the ϕ variable, while they have limited problems with the r variable. Questions that are mostly answered wrongly have some common properties, such as value. According to inferential statistics, there is no significant difference between the means of the CCDeT and CCDrT scores. The mean of the CCDeT scores is only 4.63 and the mean of the CCDrT is only 4.66. Briefly, we can say that most physics teacher candidates have problems with drawing a shape using the variables of curvilinear coordinate systems or in determining the variables of drawn shapes. Part of this study was presented at the XI. National Science and Mathematics Education Congress (UFBMEK) in 2014.

  18. Optimizing the delivery of contraceptives in low- and middle-income countries through task shifting: a systematic review of effectiveness and safety.

    PubMed

    Polus, Stephanie; Lewin, Simon; Glenton, Claire; Lerberg, Priya M; Rehfuess, Eva; Gülmezoglu, A Metin

    2015-04-01

    To assess the effectiveness and safety of task shifting for the delivery of injectable contraceptives, contraceptive implants, intrauterine devices (IUDs), tubal ligation and vasectomy in low- and middle-income countries. Multiple electronic databases were searched up to 25 May 2012 for studies which had assessed the delivery of contraceptives by health workers with lower levels of training, compared to delivery by health workers usually assigned this role, or compared to no organized provision of contraceptives. We included randomized controlled trials, non-randomized controlled trials, controlled before-after studies, and interrupted time series. Data were extracted using a standard form and the certainty of the evidence found was assessed using GRADE. We identified six randomized controlled trials published between 1977 and 1995 that assessed the safety and effectiveness of task shifting for the delivery of long-term contraceptives. Two studies assessed IUD insertion by nurses compared to doctors, two assessed IUD insertion by auxiliary nurse-midwives compared to doctors, one assessed tubal ligation by midwives compared to doctors, and one assessed the delivery of vasectomy by medical students compared to doctors. In general, little or no difference was found in contraceptive outcomes between cadres. Study design limitations and the low number of eligible studies, however, allow only limited conclusions to be drawn. The findings indicate that task shifting for the delivery of long-term contraceptives may be a safe and effective approach to increasing access to contraception. Further research is needed because the certainty of the evidence identified is variable.

  19. Does physical activity protect against drug abuse vulnerability?

    PubMed

    Bardo, Michael T; Compton, Wilson M

    2015-08-01

    The current review examined recent literature to determine our state of knowledge about the potential ability of physical activity serve as a protectant against drug abuse vulnerability. Both preclinical and clinical studies were examined using either associational or random assignment study designs. In addition to examining drug use as an outcome variable, the potential neural mediators linking physical activity and drug abuse vulnerability were examined. Several important conclusions may be drawn. First, the preclinical evidence is solid in showing that physical activity in various forms is able to serve as both a preventive and treatment intervention that reduces drug use, although voluntary alcohol drinking appears to be an exception to this conclusion. Second, the clinical evidence provides some evidence, albeit mixed, to suggest a beneficial effect of physical activity on tobacco dependent individuals. In contrast, there exists only circumstantial evidence that physical activity may reduce use of drugs other than nicotine, and there is essentially no solid information from random control studies to know if physical activity may prevent initiation of problem use. Finally, both preclinical and clinical evidence shows that various brain systems are altered by physical activity, with the medial prefrontal cortex (mPFC) serving as one potential node that may mediate the putative link between physical activity and drug abuse vulnerability. It is concluded that novel neurobehavioral approaches taking advantage of novel techniques for assessing the physiological impact of physical activity are needed and can be used to inform the longitudinal random control studies that will answer definitively the question posed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Use of predefined biochemical admission profiles does not reduce the number of tests or total cost: a randomized-controlled pilot study.

    PubMed

    Pareek, Manan; Haidl, Felix; Folkestad, Lars; Brabrand, Mikkel

    2014-02-01

    The objective of this pilot study was to evaluate whether the use of predefined biochemical profiles as an alternative to individually ordered blood tests by the treating physicians resulted in fewer tests or a lower total cost. This was a randomized-controlled trial of 191 adult patients admitted to a medical admission unit. Upon admission, the patients were randomized to have their blood tests determined by either using a predefined profile (used routinely and designed by the department head) or ordered individually by the treating physician. All patients were initially assessed by junior physicians. We compared the number of tests, estimated total cost, and length of stay. Data are presented as median (interquartile range). Differences were compared using the Wilcoxon rank-sum test and Fishers' exact test. Ninety-two patients were men, median age 65 years. Patients randomized to the use of the predefined profile had median 17 (14-22) blood tests drawn and patients randomized to physician discretion had median 17 (12-21) tests drawn (P=0.3). The median total cost of tests in the profile group was 618 DKK (493-803) and the cost in the physician group was 564 DKK (434-812) (P=0.19). Length of stay in the profile group was a median of 4 days (2-6 days) and 2 days (2-6 days) in the physician group (P=0.08). The use of a predefined blood test panel did not significantly affect the number of tests, total cost, or length of stay for acutely admitted medical patients compared with tests ordered at the discretion of the treating physician.

  1. An Entropy-Based Measure of Dependence between Two Groups of Random Variables. Research Report. ETS RR-07-20

    ERIC Educational Resources Information Center

    Kong, Nan

    2007-01-01

    In multivariate statistics, the linear relationship among random variables has been fully explored in the past. This paper looks into the dependence of one group of random variables on another group of random variables using (conditional) entropy. A new measure, called the K-dependence coefficient or dependence coefficient, is defined using…

  2. Autocorrelation peaks in congruential pseudorandom number generators

    NASA Technical Reports Server (NTRS)

    Neuman, F.; Merrick, R. B.

    1976-01-01

    The complete correlation structure of several congruential pseudorandom number generators (PRNG) of the same type and small cycle length was studied to deal with the problem of congruential PRNG almost repeating themselves at intervals smaller than their cycle lengths, during simulation of bandpass filtered normal random noise. Maximum period multiplicative and mixed congruential generators were studied, with inferences drawn from examination of several tractable members of a class of random number generators, and moduli from 2 to the 5th power to 2 to the 9th power. High correlation is shown to exist in mixed and multiplicative congruential random number generators and prime moduli Lehmer generators for shifts a fraction of their cycle length. The random noise sequences in question are required when simulating electrical noise, air turbulence, or time variation of wind parameters.

  3. A Mediterranean-style low-glycemic-load diet improves variables of metabolic syndrome in women, and addition of a phytochemical-rich medical food enhances benefits on lipoprotein metabolism.

    PubMed

    Jones, Jennifer L; Fernandez, Maria Luz; McIntosh, Mark S; Najm, Wadie; Calle, Mariana C; Kalynych, Colleen; Vukich, Clare; Barona, Jacqueline; Ackermann, Daniela; Kim, Jung Eun; Kumar, Vivek; Lott, Michelle; Volek, Jeff S; Lerman, Robert H

    2011-01-01

    The high prevalence of metabolic syndrome (MetS) has highlighted the need for effective dietary interventions to combat this growing problem. To assess the impact of a Mediterranean-style low-glycemic-load diet (control arm, n = 44) or the same diet plus a medical food containing phytosterols, soy protein, and extracts from hops and acacia (intervention arm, n = 45) on cardiometabolic risk variables in women with MetS. In this 12-week, 2-arm randomized trial, baseline, week 8 and 12, fasting blood samples were drawn to measure plasma lipids, apolipoproteins, and homocysteine. Dietary records were also collected and analyzed. There were decreases in fat and sugar intake (P < .001 for both) and increases in docosahexaenoic acid and eicosapentaenoic acid intake (P < .001 for both) over time, consistent with the prescribed diet. Regarding MetS variables, there were decreases in waist circumference, systolic and diastolic blood pressure, and plasma triglycerides in all subjects (P < .001 for all) with no differences between arms. Plasma low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol, apolipoprotein (apo) B, and apo B/apo A1 were reduced over time but to a greater extent in the intervention arm (P < .05 for all), indicating the medical food had a greater effect in altering lipoprotein metabolism. Further, medical food intake was associated with reduced plasma homocysteine (P < .01) compared to the control arm. A Mediterranean-style low-glycemic-load diet effectively reduces the variables of MetS. Addition of the medical food results in a less atherogenic lipoprotein profile and lower plasma homocysteine. Copyright © 2011 National Lipid Association. Published by Elsevier Inc. All rights reserved.

  4. Ductile alloy and process for preparing composite superconducting wire

    DOEpatents

    Verhoeven, John D.; Finnemore, Douglas K.; Gibson, Edwin D.; Ostenson, Jerome E.

    1983-03-29

    An alloy for the commercial production of ductile superconducting wire is prepared by melting together copper and at least 15 weight percent niobium under non-oxygen-contaminating conditions, and rapidly cooling the melt to form a ductile composite consisting of discrete, randomly distributed and orientated dendritic-shaped particles of niobium in a copper matrix. As the wire is worked, the dendritric particles are realigned parallel to the longitudinal axis and when drawn form a plurality of very fine ductile superconductors in a ductile copper matrix. The drawn wire may be tin coated and wound into magnets or the like before diffusing the tin into the wire to react with the niobium. Impurities such as aluminum or gallium may be added to improve upper critical field characteristics.

  5. Ductile alloy and process for preparing composite superconducting wire

    DOEpatents

    Verhoeven, J.D.; Finnemore, D.K.; Gibson, E.D.; Ostenson, J.E.

    An alloy for the commercial production of ductile superconducting wire is prepared by melting together copper and at least 15 weight percent niobium under non-oxygen-contaminating conditions, and rapidly cooling the melt to form a ductile composite consisting of discrete, randomly distributed and oriented dendritic-shaped particles of niobium in a copper matrix. As the wire is worked, the dendritic particles are realigned parallel to the longitudinal axis and when drawn form a plurality of very fine ductile superconductors in a ductile copper matrix. The drawn wire may be tin coated and wound into magnets or the like before diffusing the tin into the wire to react with the niobium. Impurities such as aluminum or gallium may be added to improve upper critical field characteristics.

  6. Clock face drawing test performance in children with ADHD.

    PubMed

    Ghanizadeh, Ahmad; Safavi, Salar; Berk, Michael

    2013-01-01

    The utility and discriminatory pattern of the clock face drawing test in ADHD is unclear. This study therefore compared Clock Face Drawing test performance in children with ADHD and controls. 95 school children with ADHD and 191 other children were matched for gender ratio and age. ADHD symptoms severities were assessed using DSM-IV ADHD checklist and their intellectual functioning was assessed. The participants completed three clock-drawing tasks, and the following four functions were assessed: Contour score, Numbers score, Hands setting score, and Center score. All the subscales scores of the three clock drawing tests of the ADHD group were lower than that of the control group. In ADHD children, inattention and hyperactivity/ impulsivity scores were not related to free drawn clock test scores. When pre-drawn contour test was performed, inattentiveness score was statistically associated with Number score while none of the other variables of age, gender, intellectual functioning, and hand use preference were associated with that kind of score. In pre-drawn clock, no association of ADHD symptoms with any CDT subscales found significant. In addition, more errors are observed with free drawn clock and Pre-drawn contour than pre-drawn clock. Putting Numbers and Hands setting are more sensitive measures to screen ADHD than Contour and Center drawing. Test performance, except Hands setting, may have already reached a developmental plateau. It is probable that Hand setting deficit in children with ADHD may not decrease from age 8 to 14 years. Performance of children with ADHD is associated with complexity of CDT.

  7. Impact of Sex Education in Kogi State, Nigeria

    ERIC Educational Resources Information Center

    Sule, H. A.; Akor, J. A.; Toluhi, O. J.; Suleiman, R. O.; Akpihi, L.; Ali, O. U.

    2015-01-01

    The focus of this study was to investigate the impact of family sex education in secondary schools on students in Kogi State, Nigeria. The descriptive survey design was used for the study. A total of 1,960 secondary school students were drawn by stratified random sampling from 40 schools within Kogi State, Nigeria. Three research questions were…

  8. Measuring Organizational Learning Capability in Indian Managers and Establishing Firm Performance Linkage: An Empirical Analysis

    ERIC Educational Resources Information Center

    Bhatnagar, Jyotsna

    2006-01-01

    Purpose: The purpose of this research is to measure Organizational Learning Capability (OLC) perception in the managers of public, private and multinational organizations and establish the link between OLC and firm performance. Design/methodology/approach: The data were collected from a sample of 612 managers randomly drawn from Indian industry,…

  9. The Effect of Graphical Representation on the Learner's Learning Interest and Achievement in Multimedia Learning

    ERIC Educational Resources Information Center

    Park, Sanghoon; Lim, Jung

    2004-01-01

    The purpose of this paper was to investigate the effects of different types of visual illustrations on learner's learning interest, motivation and achievement, especially in multimedia learning. The participants were drawn from two classes of an "Introduction to Educational Technology" course and randomly assigned to one of the three…

  10. Relationships among Teachers' Self-Efficacy and Students' Motivation, Atmosphere, and Satisfaction in Physical Education

    ERIC Educational Resources Information Center

    Pan, Yi-Hsiang

    2014-01-01

    The purpose of this study was to confirm the relationships among teachers' self-efficacy, and students' learning motivation, learning atmosphere, and learning satisfaction in senior high school physical education (PE). A sample of 462 PE teachers and 2681 students was drawn using stratified random sampling and cluster sampling from high schools in…

  11. Strategies for Coping with the Challenges of Incarceration among Nigerian Prison Inmates

    ERIC Educational Resources Information Center

    Agbakwuru, Chikwe; Awujo, Grace C.

    2016-01-01

    This paper investigated the strategies for coping with the challenges of incarceration among inmates of Port Harcourt Prison, Nigeria. The population was 2,997 inmates of the prison while the sample was 250 inmates drawn through stratified random sampling technique from the same Port Harcourt prison. Six research questions were posed and data for…

  12. Exploring the Influence of Ethnicity, Age, and Trauma on Prisoners' World Assumptions

    ERIC Educational Resources Information Center

    Gibson, Sandy

    2011-01-01

    In this study, the author explores world assumptions of prisoners, how these assumptions vary by ethnicity and age, and whether trauma history affects world assumptions. A random sample of young and old prisoners, matched for prison location, was drawn from the New Jersey Department of Corrections prison population. Age and ethnicity had…

  13. DEVELOPMENT OF INDICATORS OF EXPOSURE AND RESPONSE TO SEDIMENT AND HABITAT ALTERATION IN LAKE MICHIGAN COASTAL RIVERINE WETLANDS

    EPA Science Inventory

    Measures are being assessed to quantify the relationship of land-use in upstream watersheds to the habitat and biota in downstream coastal wetlands. Twenty-two sites were randomly drawn from a pool of 125 identified as riverine coastal wetlands along the shore of Lake Michigan. W...

  14. Demographic Prediction of Juvenile Delinquency across and within Delinquency Levels.

    ERIC Educational Resources Information Center

    Fink, Michael D.; Truckenmiller, James L.

    Demographic prediction of juvenile delinquency has been hampered by the heterogeniety of youth samples. In an attempt to correct for sampling bias in predicting juvenile delinquency, 1,689 male and female youths(aged 12 to 19, drawn from a 6 percent systematic, census tract, random sample of Pennsylvania school youths) completed the Youth Needs…

  15. Using Random Parameter Logit in Open and Distance Learning (ODL) Institutions in Malaysia

    ERIC Educational Resources Information Center

    Chiam, Chooi Chea; Loo, SzeWei

    2015-01-01

    Attention has been drawn to Open Distance Learning (ODL) as a mode for teaching and learning with the advancement in communication via the Internet. Education today has expanded the role of ICT in learning and knowledge generation, leveraging on Internet technology to transmit education across the country. Due to the advancement of technology and…

  16. Emotional Abuse of Secondary School Students by Teachers in Edo State, Nigeria

    ERIC Educational Resources Information Center

    Aluede, Oyaziwo; Ojugo, A. I.; Okoza, Jolly

    2012-01-01

    This study examined the forms of emotional abuse experienced by students and the percentage of victims that experience the various forms of emotional abuse. The survey design was adopted for this study. A total of 1,559 students drawn from public secondary schools in Edo State, Nigeria, who were randomly selected through the multi-stage…

  17. Rural Economic Development Consequences of the Population Turnaround in Northern Lower Michigan.

    ERIC Educational Resources Information Center

    West, Patrick C.; And Others

    Consequences of population turnaround for rural economic development are examined in a 9-county region of Northern Lower Michigan. Data from census reports and 374 usable responses to a questionnaire mailed to a random sample of property owners drawn from 1982 county tax assessment rolls were used to test competing hypotheses about rural…

  18. Order of Verdict Consideration and Decision Rule Effects on Mock Jury Decision Making.

    ERIC Educational Resources Information Center

    Olaye, Imafidon M.

    A study investigated the effects of order verdict consideration and decision rule on jury verdicts. After reading the summary of an actual trial, 240 mock jurors drawn from undergraduate communications classes were randomly assigned to six-member juries. Jury assignments were made under two verdict orders (ascending and descending order of…

  19. The Interrelationships of Preadolescents' Student Characteristics Influencing Selection of Career Exploration Courses [And Abstract]. Industrial Arts Education Monograph No. 1.

    ERIC Educational Resources Information Center

    Meehan, Merrill L.

    The study investigated the interaction of personal and environmental factors influencing seventh graders' selection of career exploration courses for increased exploration in the eighth grade. A stratified random sample (496 students) was drawn from the Pittsburgh Public School's Occupational, Vocational, and Technical Exploratory Program.…

  20. A Nationwide Epidemiologic Modeling Study of LD: Risk, Protection, and Unintended Impact

    ERIC Educational Resources Information Center

    McDermott, Paul A.; Goldberg, Michelle M.; Watkins, Marley W.; Stanley, Jeanne L.; Glutting, Joseph J.

    2006-01-01

    Through multiple logistic regression modeling, this article explores the relative importance of risk and protective factors associated with learning disabilities (LD). A representative national sample of 6- to 17-year-old students (N = 1,268) was drawn by random stratification and classified by the presence versus absence of LD in reading,…

  1. Construct Equivalence of a National Certification Examination that Uses Dual Languages and Audio Assistant.

    ERIC Educational Resources Information Center

    Wang, Shudong; Wang, Ning; Hoadley, David

    This study examined the comparability of scores on the National Nurses Aides Assessment Program (NNAAP) test across language and administration condition groups for calibration and validation samples that were randomly drawn from the same population. A sample of 20,568 candidate responses to 1 test form was used. This examination is given in…

  2. Mothers' Antenatal Depression and Their Children's Antisocial Outcomes

    ERIC Educational Resources Information Center

    Hay, Dale F.; Pawlby, Susan; Waters, Cerith S.; Perra, Oliver; Sharp, Deborah

    2010-01-01

    Interviews of 120 British adolescents and their parents (80% of a random sample of antenatal patients drawn from a representative urban population and followed longitudinally) revealed that 40 (33%) had been arrested and/or had a diagnosis of "DSM-IV" conduct disorder by 16 years of age; of those, 18 (45%) had committed violent acts.…

  3. Social-Economic Factors, Student Factors, Student Academic Goals and Performance of Students in Institutions of Higher Learning in Uganda

    ERIC Educational Resources Information Center

    Ngoma, Muhammed; Ntale, Peter Dithan; Abaho, Earnest

    2017-01-01

    This article evaluates the relationship between social-economic factors, students' factors, student academic goals and performance of students. The study adopts a cross-sectional survey, with largely quantitative approaches. A sample of 950 students was randomly and proportionately drawn from undergraduates in four institutions of higher learning.…

  4. Arts and the Quality of Life: An Exploratory Study

    ERIC Educational Resources Information Center

    Michalos, Alex C.

    2005-01-01

    The aim of this investigation was to measure the impact of the arts broadly construed on the quality of life. A randomly drawn household sample of 315 adult residents of Prince George, British Columbia served as the working data-set. Examining zero-order correlations, among other things, it was found that playing a musical instrument a number of…

  5. Free-Response and Multiple-Choice Items: Measures of the Same Ability?

    ERIC Educational Resources Information Center

    Bennett, Randy Elliot; And Others

    This study examined the relationship of multiple-choice and free-response items contained on the College Board's Advanced Placement Computer Science (APCS) examination. Subjects were two samples of 1,000 randomly drawn from the population of 7,372 high school students taking the 1988 examination of the APCS "AB" form. Most were high…

  6. An aging population: relationships between socio-demographics, motivations and participation

    Treesearch

    Karen Robinson; Robert C. Burns; Chad D. Pierskalla; Alan Graefe

    2008-01-01

    The purpose of this study was to examine the outdoor recreation behavior of Oregon's aging population, including developing a socio-demographic profile and examining the importance of their current motivations with the importance of their expected motivations 10 years from now. A stratified random sample was drawn of Oregon residents, and a mailback questionnaire...

  7. Characteristics and Experiences Related to VTAE Programs That Encourage and/or Inhibit Entrepreneurial Competencies. Final Report.

    ERIC Educational Resources Information Center

    Gilbertson, Alan; And Others

    A study examined the characteristics and features of vocational, technical, and adult education (VTAE) programs that encourage and/or inhibit entrepreneurship competencies. The study population included random samples of 50 students drawn from each of Wisconsin's VTAE districts, 30 occupational instructors from each district, and 30 graduates of…

  8. Homosexual parents: a comparative forensic study of character and harms to children.

    PubMed

    Cameron, P; Cameron, K

    1998-06-01

    40 appeals cases of custody disputes drawn systematically from all cases involving a homosexual parent in the United States were compared to 38 appeals cases involving heterosexual custody disputes drawn randomly from listings under parental "character" and 18 appeals cases drawn randomly from "general" cases in Dicennial Digest from 1966 to 1991. Each case involving homosexual vs heterosexual claimants was examined for recorded information about (1) the character of the homosexual parent, the associates of the homosexual parent, the heterosexual parent, and the associates of the heterosexual parent, (2) the effects, particularly harms, upon the child(ren), and (3) psychiatric opinion. 82% of the homosexual vs 18% of the heterosexual parents and 54% of the homosexual's associates vs 19% of the heterosexuals' associates were recorded as having poor character in cases involving a homosexual claimant. Of the 66 recorded harms, e.g., molestation, physical abuse, to the 73 children, homosexual persons accounted for 64 (97%). Of the 32 lesbians, 6 were recorded as having engaged in criminal activity and 3 of bringing false charges of child sexual abuse against the father. Psychiatric opinion, however, ran 25 to 12 in favor of custody for the homosexual parent. In the 56 heterosexual vs heterosexual comparison cases, 38% of the heterosexual parents and 28% of their associates were recorded as having poor character. Six harms to their 105 children and 3 instances of criminality but no false charges of sexual abuse were recorded. In the appeals court literature, homosexual parents were disproportionately of poor character and disproportionately associated with various harms to their children.

  9. Contextuality in canonical systems of random variables

    NASA Astrophysics Data System (ADS)

    Dzhafarov, Ehtibar N.; Cervantes, Víctor H.; Kujala, Janne V.

    2017-10-01

    Random variables representing measurements, broadly understood to include any responses to any inputs, form a system in which each of them is uniquely identified by its content (that which it measures) and its context (the conditions under which it is recorded). Two random variables are jointly distributed if and only if they share a context. In a canonical representation of a system, all random variables are binary, and every content-sharing pair of random variables has a unique maximal coupling (the joint distribution imposed on them so that they coincide with maximal possible probability). The system is contextual if these maximal couplings are incompatible with the joint distributions of the context-sharing random variables. We propose to represent any system of measurements in a canonical form and to consider the system contextual if and only if its canonical representation is contextual. As an illustration, we establish a criterion for contextuality of the canonical system consisting of all dichotomizations of a single pair of content-sharing categorical random variables. This article is part of the themed issue `Second quantum revolution: foundational questions'.

  10. Repeated exposure to media messages encouraging parent-child communication about sex: differential trajectories for mothers and fathers.

    PubMed

    Blitstein, Jonathan L; Evans, W Douglas; Davis, Kevin C; Kamyab, Kian

    2012-01-01

    To examine changes in parent-child communication related to sexual behavior after exposure to public health messages. Randomized, controlled trial that was part of precampaign message testing. Exposure occurred online or through DVDs mailed to participants and viewed on their personal computers. Data collection occurred via a secure Web site. Participants included parents (n  =  1969) living with a child age 10 to 14 years drawn from a nationally representative sample of U.S. households. Treatment participants were exposed to video, audio, and print advertisements that promoted the benefits of speaking to their children early and often about delaying initiation of sexual activity; messages also directed parents to an informational Web site. The dependent variable assessed frequency of parent-child communication related to sexual behavior. The primary independent variable was treatment assignment. Longitudinal growth modeling that included five waves of data. The trajectory of growth over time differed between fathers in the treatment group and fathers in the control group (F[1, 2357]  =  4.15; p < .042), indicating more frequent communication among treatment fathers than among control fathers. Trajectories did not differ between mothers in treatment and control groups. This study demonstrates that father-child and mother-child communication patterns differ over time in response to public health messages. Findings have implication for researchers developing health marketing campaigns.

  11. RoboPol: the optical polarization of gamma-ray-loud and gamma-ray-quiet blazars

    NASA Astrophysics Data System (ADS)

    Angelakis, E.; Hovatta, T.; Blinov, D.; Pavlidou, V.; Kiehlmann, S.; Myserlis, I.; Böttcher, M.; Mao, P.; Panopoulou, G. V.; Liodakis, I.; King, O. G.; Baloković, M.; Kus, A.; Kylafis, N.; Mahabal, A.; Marecki, A.; Paleologou, E.; Papadakis, I.; Papamastorakis, I.; Pazderski, E.; Pearson, T. J.; Prabhudesai, S.; Ramaprakash, A. N.; Readhead, A. C. S.; Reig, P.; Tassis, K.; Urry, M.; Zensus, J. A.

    2016-12-01

    We present average R-band optopolarimetric data, as well as variability parameters, from the first and second RoboPol observing season. We investigate whether gamma-ray-loud and gamma-ray-quiet blazars exhibit systematic differences in their optical polarization properties. We find that gamma-ray-loud blazars have a systematically higher polarization fraction (0.092) than gamma-ray-quiet blazars (0.031), with the hypothesis of the two samples being drawn from the same distribution of polarization fractions being rejected at the 3σ level. We have not found any evidence that this discrepancy is related to differences in the redshift distribution, rest-frame R-band luminosity density, or the source classification. The median polarization fraction versus synchrotron-peak-frequency plot shows an envelope implying that high-synchrotron-peaked sources have a smaller range of median polarization fractions concentrated around lower values. Our gamma-ray-quiet sources show similar median polarization fractions although they are all low-synchrotron-peaked. We also find that the randomness of the polarization angle depends on the synchrotron peak frequency. For high-synchrotron-peaked sources, it tends to concentrate around preferred directions while for low-synchrotron-peaked sources, it is more variable and less likely to have a preferred direction. We propose a scenario which mediates efficient particle acceleration in shocks and increases the helical B-field component immediately downstream of the shock.

  12. Variables in Elementary Mathematics Education

    ERIC Educational Resources Information Center

    Brizuela, Bárbara M.

    2016-01-01

    In this article, I analyze episodes from two third-grade classrooms drawn from a larger classroom teaching experiment to explore how these students began to incorporate nonnumerical symbols in their mathematical expressions when asked to represent indeterminate quantities. The article addresses two research questions: What understandings did these…

  13. Understanding Bhutanese Refugee Suicide Through the Interpersonal-Psychological Theory of Suicidal Behavior

    PubMed Central

    Ellis, B. Heidi; Lankau, Emily W.; Ao, Trong; Benson, Molly A.; Miller, Alisa B.; Shetty, Sharmila; Cardozo, Barbara Lopes; Geltman, Paul L.; Cochran, Jennifer

    2016-01-01

    Attention has been drawn to high rates of suicide among refugees after resettlement and in particular among the Bhutanese refugees. This study sought to understand the apparent high rates of suicide among resettled Bhutanese refugees in the context of the Interpersonal-Psychological Theory of Suicidal Behavior (IPTS). Expanding on a larger investigation of suicide in a randomly selected sample of Bhutanese men and women resettled in Arizona, Georgia, New York, and Texas (Ao et al., 2012), the current study focused on 2 factors, thwarted belongingness and perceived burdensomeness, examined individual and postmigration variables associated with these factors, and explored how they differed by gender. Overall, factors such as poor health were associated with perceived burdensomeness and thwarted belongingness. For men, stressors related to employment and providing for their families were related to feeling burdensome and/or alienated from family and friends, whereas for women, stressors such as illiteracy, family conflict, and being separated from family members were more associated. IPTS holds promise in understanding suicide in the resettled Bhutanese community. PMID:25642653

  14. Progressive calibration and averaging for tandem mass spectrometry statistical confidence estimation: Why settle for a single decoy?

    PubMed Central

    Keich, Uri; Noble, William Stafford

    2017-01-01

    Estimating the false discovery rate (FDR) among a list of tandem mass spectrum identifications is mostly done through target-decoy competition (TDC). Here we offer two new methods that can use an arbitrarily small number of additional randomly drawn decoy databases to improve TDC. Specifically, “Partial Calibration” utilizes a new meta-scoring scheme that allows us to gradually benefit from the increase in the number of identifications calibration yields and “Averaged TDC” (a-TDC) reduces the liberal bias of TDC for small FDR values and its variability throughout. Combining a-TDC with “Progressive Calibration” (PC), which attempts to find the “right” number of decoys required for calibration we see substantial impact in real datasets: when analyzing the Plasmodium falciparum data it typically yields almost the entire 17% increase in discoveries that “full calibration” yields (at FDR level 0.05) using 60 times fewer decoys. Our methods are further validated using a novel realistic simulation scheme and importantly, they apply more generally to the problem of controlling the FDR among discoveries from searching an incomplete database. PMID:29326989

  15. Adjuvant role of vitamin B analogue (sulbutiamine) with anti-infective treatment in infection associated asthenia.

    PubMed

    Shah, Siddharth N

    2003-09-01

    Asthenic symptoms such as weakness accompany illness. This study investigates whether the centrally acting cholinergic agent, vitamin B analogue (sulbutiamine), is effective and acceptable in relieving these symptoms in infectious disease when combined with specific anti-infective treatment. In a prospective uncontrolled, non-randomised, commercial, observational study, 1772 patients with an infectious disease and asthenic symptoms, drawn from the practice of 350 randomly selected physicians throughout India, received vitamin B analogue (sulbutiamine) in addition to specific anti-infective treatment for 15 days. The primary outcome variable was complete resolution of asthenic symptoms with treatment. The number (%, 95% confidence interval) of patients with complete resolution of all asthenic symptoms was 916 (51.7, 49.4-54). In the remaining patients, severe asthenia was reduced but persisted in 11 (0.6, 0-26); and moderate asthenia in 94 (5.3, 0-17.6). The response was greater in patients with acute infection and symptoms more related to cerebral function. Side effects occurred in 10 (0.6%), patients and well being improved significantly. Vitamin B analogue (sulbutiamine) may be a useful adjunct to specific anti-infective treatment.

  16. A random variance model for detection of differential gene expression in small microarray experiments.

    PubMed

    Wright, George W; Simon, Richard M

    2003-12-12

    Microarray techniques provide a valuable way of characterizing the molecular nature of disease. Unfortunately expense and limited specimen availability often lead to studies with small sample sizes. This makes accurate estimation of variability difficult, since variance estimates made on a gene by gene basis will have few degrees of freedom, and the assumption that all genes share equal variance is unlikely to be true. We propose a model by which the within gene variances are drawn from an inverse gamma distribution, whose parameters are estimated across all genes. This results in a test statistic that is a minor variation of those used in standard linear models. We demonstrate that the model assumptions are valid on experimental data, and that the model has more power than standard tests to pick up large changes in expression, while not increasing the rate of false positives. This method is incorporated into BRB-ArrayTools version 3.0 (http://linus.nci.nih.gov/BRB-ArrayTools.html). ftp://linus.nci.nih.gov/pub/techreport/RVM_supplement.pdf

  17. Diverging conductance at the contact between random and pure quantum XX spin chains

    NASA Astrophysics Data System (ADS)

    Chatelain, Christophe

    2017-11-01

    A model consisting of two quantum XX spin chains, one homogeneous and the second with random couplings drawn from a binary distribution, is considered. The two chains are coupled to two different non-local thermal baths and their dynamics is governed by a Lindblad equation. In the steady state, a current J is induced between the two chains by coupling them together by their edges and imposing different chemical potentials μ to the two baths. While a regime of linear characteristics J versus Δμ is observed in the absence of randomness, a gap opens as the disorder strength is increased. In the infinite-randomness limit, this behavior is related to the density of states of the localized states contributing to the current. The conductance is shown to diverge in this limit.

  18. Automated mapping of the ocean floor using the theory of intrinsic random functions of order k

    USGS Publications Warehouse

    David, M.; Crozel, D.; Robb, James M.

    1986-01-01

    High-quality contour maps can be computer drawn from single track echo-sounding data by combining Universal Kriging and the theory of intrinsic random function of order K (IRFK). These methods interpolate values among the closely spaced points that lie along relatively widely spaced lines. The technique provides a variance which can be contoured as a quantitative measure of map precision. The technique can be used to evaluate alternative survey trackline configurations and data collection intervals, and can be applied to other types of oceanographic data. ?? 1986 D. Reidel Publishing Company.

  19. Maximum-entropy probability distributions under Lp-norm constraints

    NASA Technical Reports Server (NTRS)

    Dolinar, S.

    1991-01-01

    Continuous probability density functions and discrete probability mass functions are tabulated which maximize the differential entropy or absolute entropy, respectively, among all probability distributions with a given L sub p norm (i.e., a given pth absolute moment when p is a finite integer) and unconstrained or constrained value set. Expressions for the maximum entropy are evaluated as functions of the L sub p norm. The most interesting results are obtained and plotted for unconstrained (real valued) continuous random variables and for integer valued discrete random variables. The maximum entropy expressions are obtained in closed form for unconstrained continuous random variables, and in this case there is a simple straight line relationship between the maximum differential entropy and the logarithm of the L sub p norm. Corresponding expressions for arbitrary discrete and constrained continuous random variables are given parametrically; closed form expressions are available only for special cases. However, simpler alternative bounds on the maximum entropy of integer valued discrete random variables are obtained by applying the differential entropy results to continuous random variables which approximate the integer valued random variables in a natural manner. All the results are presented in an integrated framework that includes continuous and discrete random variables, constraints on the permissible value set, and all possible values of p. Understanding such as this is useful in evaluating the performance of data compression schemes.

  20. Observation chart design features affect the detection of patient deterioration: a systematic experimental evaluation.

    PubMed

    Christofidis, Melany J; Hill, Andrew; Horswill, Mark S; Watson, Marcus O

    2016-01-01

    To systematically evaluate the impact of several design features on chart-users' detection of patient deterioration on observation charts with early-warning scoring-systems. Research has shown that observation chart design affects the speed and accuracy with which abnormal observations are detected. However, little is known about the contribution of individual design features to these effects. A 2 × 2 × 2 × 2 mixed factorial design, with data-recording format (drawn dots vs. written numbers), scoring-system integration (integrated colour-based system vs. non-integrated tabular system) and scoring-row placement (grouped vs. separate) varied within-participants and scores (present vs. absent) varied between-participants by random assignment. 205 novice chart-users, tested between March 2011-March 2014, completed 64 trials where they saw real patient data presented on an observation chart. Each participant saw eight cases (four containing abnormal observations) on each of eight designs (which represented a factorial combination of the within-participants variables). On each trial, they assessed whether any of the observations were physiologically abnormal, or whether all observations were normal. Response times and error rates were recorded for each design. Participants responded faster (scores present and absent) and made fewer errors (scores absent) using drawn-dot (vs. written-number) observations and an integrated colour-based (vs. non-integrated tabular) scoring-system. Participants responded faster using grouped (vs. separate) scoring-rows when scores were absent, but separate scoring-rows when scores were present. Our findings suggest that several individual design features can affect novice chart-users' ability to detect patient deterioration. More broadly, the study further demonstrates the need to evaluate chart designs empirically. © 2015 John Wiley & Sons Ltd.

  1. The effect of asset-based wealth inequality on problem drinking among rural Thai elders: A prospective population-based cohort study☆

    PubMed Central

    Jirapramukpitak, Tawanchai; Abas, Melanie; Tangchonlatip, Kanchana; Punpuing, Sureeporn

    2014-01-01

    Evidence on the link between income inequality and alcohol-related problems is scarce, inconclusive and dominated by studies from the developed world. The use of income as a proxy measure for wealth is also questionable, particularly in developing countries. The goal of the present study is to explore the contextual influence of asset-based wealth inequality on problem drinking among Thai older adults. A population-based cohort study with a one-year follow-up was nested in a Demographic Surveillance System (DSS) of 100 villages in western Thailand. Data were drawn from a random sample of 1104 older residents, aged 60 or over (one per household) drawn from all 100 villages, of whom 982 (89%) provided problem drinking data at follow-up. The primary outcome measure was a validated Thai version of the Alcohol-Used Disorder Identification Test for problem drinking. Living in areas of high wealth inequality was prospectively associated with a greater risk for problem drinking among older people (adjusted odds ratio 2.30, 95% confidence intervals 1.02–5.22), after adjusting for individual-level and village-level factors. A rise in wealth inequality over the year was also independently associated with an increased risk of problem drinking (adjusted odds ratio 2.89, 95% confidence intervals 1.24–6.65). The associations were not explained by the social capital, status anxiety or psychosocial stress variables. The data suggest that wealth inequality and an increase in inequality across time lead to a greater risk of problem drinking. Efforts should be directed towards reducing gaps and preventing large jumps in inequality in the communities. Further research should investigate the effect of asset-based inequality on various health risk behaviors and its specific mediating pathways. PMID:24444845

  2. Sources of Life Strengths as Predictors of Late-Life Mortality and Survivorship

    ERIC Educational Resources Information Center

    Fry, Prem S.; Debats, Dominique L.

    2006-01-01

    The aim of the research was to determine within a single study the extent to which demographic factors, self-rated-health and psychosocial factors present the strongest risks or benefits to older adults' mortality in the course of a 5.9-year longitudinal follow-up. The initial sample of 732 individuals was drawn randomly from the registry listings…

  3. Types of Bullying in the Senior High Schools in Ghana

    ERIC Educational Resources Information Center

    Antiri, Kwasi Otopa

    2016-01-01

    The main objective of the study was to examine the types of bullying that were taking place in the senior high schools in Ghana. A multi-stage sampling procedure, comprising purposive, simple random and snowball sampling technique, was used in the selection of the sample. A total of 354 respondents were drawn six schools in Ashanti, Central and…

  4. The Relationship between School Achievement and Peer Harassment in Canadian Adolescents: The Importance of Mediating Factors

    ERIC Educational Resources Information Center

    Beran, Tanya N.; Lupart, Judy

    2009-01-01

    The relationship between school achievement and peer harassment was examined using individual and peer characteristics as mediating factors. The sample consisted of adolescents age 12-15 years (n = 4,111) drawn from the Canadian National Longitudinal Survey of Children and Youth, which is a stratified random sample of 22,831 households in Canada.…

  5. Occupational Commonalities: A Base for Course Construction. Paper No. 2219, Journal Series.

    ERIC Educational Resources Information Center

    Dillon, Roy D.; Horner, James T.

    To determine competencies and activities used by workers in a cross section of the statewide labor force, data were obtained from a random sample of 1,500 employed persons drawn from 14 purposively selected index counties in Nebraska. An interview-questionnaire procedure yielded an 87.7 percent response to a checklist of 144 activities, duties,…

  6. How Generalizable Is Your Experiment? An Index for Comparing Experimental Samples and Populations

    ERIC Educational Resources Information Center

    Tipton, Elizabeth

    2014-01-01

    Although a large-scale experiment can provide an estimate of the average causal impact for a program, the sample of sites included in the experiment is often not drawn randomly from the inference population of interest. In this article, we provide a generalizability index that can be used to assess the degree of similarity between the sample of…

  7. IDENTIFICATION OF OFF-FARM AGRICULTURAL OCCUPATIONS AND THE EDUCATION NEEDED FOR EMPLOYMENT IN THESE OCCUPATIONS IN DELAWARE.

    ERIC Educational Resources Information Center

    BARWICK, RALPH P.

    THE PURPOSES OF THE STUDY WERE TO (1) IDENTIFY PRESENT AND EMERGING OFF-FARM AGRICULTURAL OCCUPATIONS, (2) ESTIMATE THE NUMBER EMPLOYED, (3) ESTIMATE THE NUMBER TO BE EMPLOYED IN THE FUTURE, AND (4) DETERMINE COMPETENCIES NEEDED IN SELECTED OCCUPATIONAL FAMILIES. A DISPROPORTIONATE RANDOM SAMPLE OF 267 BUSINESSES OR SERVICES WAS DRAWN FROM A LIST…

  8. Parent-Client Participation in the Bilingual Education Program in St. Croix, United States Virgin Islands.

    ERIC Educational Resources Information Center

    Padgett, Carmen H. A.

    A study of a St. Croix bilingual education program looked at parent involvement from the program's beginning to the present and at parent recommendations for more meaningful involvement. A random sample of parents representing students at all grade levels was drawn from school records. The parents were surveyed by questionnaire, and interviewed.…

  9. The Influence of Parental Background on Students' Academic Performance in Physics in WASSCS 2000-2005

    ERIC Educational Resources Information Center

    Ebong, Samuel T.

    2015-01-01

    The study investigated parental background on student's academic performance in secondary schools in Abak local government, Akwa Ibom State, Nigeria. A survey design was adopted for the study. One thousand four hundred and forty (1440) senior secondary three (SS3) Physics students were drawn by simple random sampling from 12 Schools, six (6) each…

  10. Structural Relations among Spirituality, Religiosity, and Thriving in Adolescence

    ERIC Educational Resources Information Center

    Dowling, Elizabeth M.; Gestsdottir, Steinunn; Anderson, Pamela M.; Von Eye, Alexander; Almerigi, Jason; Lerner, Richard M.

    2004-01-01

    Using the randomly selected subsample of 1,000 youth (472 boys, M age = 12.2 years, SD = 1.5; 528 girls, M age = 12.1 years, SD = 1.4) drawn by Dowling, Getsdottir, Anderson, von Eye, and Lerner (in press) from a Search Institute (1984) archival data set, Young Adolescents and Their Parents (YAP), this research employed structural equation…

  11. The Validity of the Major Field Test in Psychology as a Programme Assessment Tool

    ERIC Educational Resources Information Center

    Gallagher, Shawn P.; Cook, Shaun P.

    2013-01-01

    The Major Field Test in Psychology (MFT) is a standardised test designed to assess subject mastery at the conclusion of an undergraduate career. Eighty-one graduating majors completed the MFT and 56 of them also took a multiple-choice exam of questions drawn randomly from an introductory psychology test bank. Like the MFT, the constructed exam was…

  12. The Relationships of Color to the Attribution of Positive or Negative Affect.

    ERIC Educational Resources Information Center

    Sexton, Donna J.; And Others

    The purpose of the study was to experimentally determine if the attribution of positive or negative social values is associated with particular colors. The subjects were 76 four-and five-year old females drawn from six privately owned kindergartens and nurseries. The children were randomly assigned to one of two groups. In the control group, color…

  13. Evaluation of Achievement of Universal Basic Education (UBE) in Delta State

    ERIC Educational Resources Information Center

    Osadebe, P. U.

    2014-01-01

    The study evaluated the objectives of the Universal Basic Education (UBE) programme in Delta State. It considered the extent to which each objective was achieved. A research question on the extent to which the UBE objectives were achieved guided the study. Two hypotheses were tested. A sample of 300 students was randomly drawn through the use of…

  14. Pilot Survey of Young African American Males in Four Cities.

    ERIC Educational Resources Information Center

    Harris (Louis) and Associates, Inc., New York, NY.

    A pilot survey was conducted to explore why some young African American men living in cities stay in high school and why others drop out. Between October 1993 and March 1994, face-to-face interviews were conducted with 360 young black men aged 17 to 22, randomly drawn from census tracts in New York (New York), Chicago (Illinois), Los Angeles…

  15. Systematic sampling of discrete and continuous populations: sample selection and the choice of estimator

    Treesearch

    Harry T. Valentine; David L. R. Affleck; Timothy G. Gregoire

    2009-01-01

    Systematic sampling is easy, efficient, and widely used, though it is not generally recognized that a systematic sample may be drawn from the population of interest with or without restrictions on randomization. The restrictions or the lack of them determine which estimators are unbiased, when using the sampling design as the basis for inference. We describe the...

  16. Ethnic Differences in the Nutritiousness of Diets of Hawai'i's Children.

    ERIC Educational Resources Information Center

    Lai, Morris K.; Shimabukuro, Sandra

    Data on the nutritional quality of Hawaiian children's diet, arranged by age and ethnic group, are presented in this paper. The data are drawn from a random sampling of the diets of 890 students. Tables show mean nutritional intake and the percent of calories from protein, carbohydrate and fat for elementary, junior high and senior high school…

  17. Political Empowerment of Women through Literacy Education Programmes in EDO and Delta States, Nigeria

    ERIC Educational Resources Information Center

    Olomukoro, Caroline O.; Adelore, Omobola O.

    2015-01-01

    The study examined the political empowerment of women through literacy education programmes in Edo and Delta States in the South-South Geopolitical zone of Nigeria. A sample of 1022 women was randomly drawn from the different levels of literacy classes organised by the Agency of Adult and Nonformal Education and non-governmental and private…

  18. High Level of Emotional Intelligence Is Related to High Level of Online Teaching Self-Efficacy among Academic Nurse Educators

    ERIC Educational Resources Information Center

    Ali, Nagia; Ali, Omar; Jones, James

    2017-01-01

    This study examined the relationship between emotional intelligence (EI) and online teaching self-efficacy among 115 academic nurse educators who teach online (totally, blended, or both). The sample was randomly drawn from the list of nursing schools accredited by Commission on Collegiate Nursing Education (CCNE) with baccalaureate, master's…

  19. Internet-Users and Internet Non-Users Attitude towards Research: A Comparative Study on Post-Graduate Students

    ERIC Educational Resources Information Center

    Noor ul Amin, Syed

    2017-01-01

    The purpose of the present study was to compare the Internet-user and Internet Non-user post-graduate students on their attitude towards research. The sample comprised 600 post graduate students (300 Internet-users and 300 Internet-Non-users) drawn from different faculties of University of Kashmir (J&K), India. Random sampling technique was…

  20. Predictive Factors in Undergraduates' Involvement in Campus Secret Cults in Public Universities in Edo State of Nigeria

    ERIC Educational Resources Information Center

    Azetta Arhedo, Philip; Aluede, Oyaziwo; Adomeh, Ilu O. C.

    2011-01-01

    This study examined the predictive factors in undergraduates' involvement in campus secret cults in public universities in Edo State of Nigeria. The study employed the descriptive method, specifically the survey format. A random sample of three hundred and eighty (380) undergraduates was drawn from the two public universities. Data were elicited…

  1. A Study of Ontogenetic and Generational Change in Adolescent Personality by Means of Multivariate Longitudinal Sequences: Phase II. Final Report.

    ERIC Educational Resources Information Center

    Nesselroade, John R.; Baltes, Paul B.

    Assessment of the relationship between ontogenetic (individual) and generational (historical) change in adolescent personality development was the focus of this study. The total sample included 1000 male and female adolescents (ages 13-18) randomly drawn from 32 public school systems in West Virginia following a design using longitudinal sequences…

  2. Connecting Work and School: A Statewide Study of Employer Participation in Florida School-to-Work Initiatives.

    ERIC Educational Resources Information Center

    Haley, Mary

    A study assessed the characteristics and practices of employers participating in Florida school-to-work (STW) initiatives, the factors influencing their participation, and the quality and value of their partnerships with schools. Data were gathered through a statewide mail survey of a random sample of employers drawn from more than 15,000 Florida…

  3. International News in the Canadian and American Press: A Comparative News Flow Study.

    ERIC Educational Resources Information Center

    Sparkes, Vernone M.; Robinson, Gertrude Joch

    This study tested the power of "elite nation" factors (trade, population, and gross national product) to predict the amount of foreign news coverage for specific countries. A composite week for the first quarter of 1975 was randomly drawn, and ten Canadian and twenty-nine United States newspapers were coded for all news items reported on…

  4. Rigor in Qualitative Social Work Research: A Review of Strategies Used in Published Articles

    ERIC Educational Resources Information Center

    Barusch, Amanda; Gringeri, Christina; George, Molly

    2011-01-01

    This study was conducted to describe strategies used by social work researchers to enhance the rigor of their qualitative work. A template was developed and used to review a random sample of 100 articles drawn from social work journals listed in the "2005 Journal Citation Reports: Science and Social Sciences Edition." Results suggest that the most…

  5. Effect of Self Regulated Learning Approach on Junior Secondary School Students' Achievement in Basic Science

    ERIC Educational Resources Information Center

    Nwafor, Chika E.; Obodo, Abigail Chikaodinaka; Okafor, Gabriel

    2015-01-01

    This study explored the effect of self-regulated learning approach on junior secondary school students' achievement in basic science. Quasi-experimental design was used for the study.Two co-educational schools were drawn for the study through simple random sampling technique. One school was assigned to the treatment group while the other was…

  6. Fitting distributions to microbial contamination data collected with an unequal probability sampling design.

    PubMed

    Williams, M S; Ebel, E D; Cao, Y

    2013-01-01

    The fitting of statistical distributions to microbial sampling data is a common application in quantitative microbiology and risk assessment applications. An underlying assumption of most fitting techniques is that data are collected with simple random sampling, which is often times not the case. This study develops a weighted maximum likelihood estimation framework that is appropriate for microbiological samples that are collected with unequal probabilities of selection. A weighted maximum likelihood estimation framework is proposed for microbiological samples that are collected with unequal probabilities of selection. Two examples, based on the collection of food samples during processing, are provided to demonstrate the method and highlight the magnitude of biases in the maximum likelihood estimator when data are inappropriately treated as a simple random sample. Failure to properly weight samples to account for how data are collected can introduce substantial biases into inferences drawn from the data. The proposed methodology will reduce or eliminate an important source of bias in inferences drawn from the analysis of microbial data. This will also make comparisons between studies and the combination of results from different studies more reliable, which is important for risk assessment applications. © 2012 No claim to US Government works.

  7. On the minimum of independent geometrically distributed random variables

    NASA Technical Reports Server (NTRS)

    Ciardo, Gianfranco; Leemis, Lawrence M.; Nicol, David

    1994-01-01

    The expectations E(X(sub 1)), E(Z(sub 1)), and E(Y(sub 1)) of the minimum of n independent geometric, modifies geometric, or exponential random variables with matching expectations differ. We show how this is accounted for by stochastic variability and how E(X(sub 1))/E(Y(sub 1)) equals the expected number of ties at the minimum for the geometric random variables. We then introduce the 'shifted geometric distribution' and show that there is a unique value of the shift for which the individual shifted geometric and exponential random variables match expectations both individually and in the minimums.

  8. Students' Misconceptions about Random Variables

    ERIC Educational Resources Information Center

    Kachapova, Farida; Kachapov, Ilias

    2012-01-01

    This article describes some misconceptions about random variables and related counter-examples, and makes suggestions about teaching initial topics on random variables in general form instead of doing it separately for discrete and continuous cases. The focus is on post-calculus probability courses. (Contains 2 figures.)

  9. A Study of Array Direction HDPE Fiber Reinforced Mortar

    NASA Astrophysics Data System (ADS)

    Kamsuwan, Trithos

    2018-02-01

    This paper presents the effect of array direction HDPE fiber using as the reinforced material in cement mortar. The experimental data were created reference to the efficiency of using HDPE fiber reinforced on the tensile properties of cement mortar with different high drawn ratio of HDPE fibers. The fiber with the different drawn ratio 25x (d25 with E xx), and 35x (d35 with E xx) fiber volume fraction (0%, 1.0%, 1.5%) and fiber length 20 mm. were used to compare between random direction and array direction of HDPE fibers and the stress - strain displacement relationship behavior of HDPE short fiber reinforced cement mortar were investigated. It was found that the array direction with HDPE fibers show more improved in tensile strength and toughness when reinforced in cement mortar.

  10. The Dynamic Model and Inherent Variability: The Case of Northern France.

    ERIC Educational Resources Information Center

    Hornsby, David

    1999-01-01

    Explores the claims of the "dynamic" model of variation by testing against data recorded in Avion, Northern France. Parallels are drawn between "langue d'oil" areas of France and decreolization situations in which proponents of the dynamic model have generally worked. (Author/VWL)

  11. Ethnic and Socioeconomic Status Differences in Human Figure Drawings

    ERIC Educational Resources Information Center

    Adler, Peter T.

    1971-01-01

    Human figures drawn by psychiatric patients were evaluated. It was hypothesized that differences in performance, particularly differences reflecting a lower level of cognitive maturity, would be associated with the sociocultural background variables, and that these differences might well be such as to be misinterpreted as psychopathologically…

  12. Pharmacokinetics of S-ketamine during prolonged sedation at the pediatric intensive care unit.

    PubMed

    Flint, Robert B; Brouwer, Carole N M; Kränzlin, Anne S C; Lie-A-Huen, Loraine; Bos, Albert P; Mathôt, Ron A A

    2017-11-01

    S-ketamine is the S(+)-enantiomer of the racemic mixture ketamine, an anesthetic drug providing both sedation and analgesia. In clinical practice, significant interpatient variability in drug effect of S-ketamine is observed during long-term sedation. The aim of this study was to evaluate the pharmacokinetic variability of S-ketamine in children aged 0-18 years during long-term sedation. Twenty-five children (median age: 0.42 years, range: 0.02-12.5) received continuous intravenous administrations of 0.3-3.6 mg/kg/h S-ketamine for sedation during mechanical ventilation. Infusion rates were adjusted to the desired level of sedation and analgesia based on the COMFORT-B score and Visual Analog Scale. Blood samples were drawn once daily at random time-points, and at 1 and 4 hours after discontinuation of S-ketamine infusion. Time profiles of plasma concentrations of S-ketamine and active metabolite S-norketamine were analyzed using nonlinear mixed-effects modeling software. Clearance and volume of distribution were allometrically scaled using the ¾ power model. A total of 86 blood samples were collected. A 2-compartment and 1-compartment model adequately described the PK of S-ketamine and S-norketamine, respectively. The typical parameter estimates for clearance and central and peripheral volumes of distribution were: CL S - KETAMINE =112 L/h/70 kg, V1 S- KETAMINE =7.7 L/70 kg, V2 S- KETAMINE =545L/70 kg, Q S - kETAMINE =196 L/h/70 kg, and CL S - NORKETAMINE =53 L/h/70 kg. Interpatient variability of CL S - KETAMINE and CL S - NORKETAMINE was considerable with values of 40% and 104%, respectively, leading to marked variability in steady-state plasma concentrations. Substantial interpatient variability in pharmacokinetics in children complicates the development of adequate dosage regimen for continuous sedation. © 2017 John Wiley & Sons Ltd.

  13. A Multivariate Randomization Text of Association Applied to Cognitive Test Results

    NASA Technical Reports Server (NTRS)

    Ahumada, Albert; Beard, Bettina

    2009-01-01

    Randomization tests provide a conceptually simple, distribution-free way to implement significance testing. We have applied this method to the problem of evaluating the significance of the association among a number (k) of variables. The randomization method was the random re-ordering of k-1 of the variables. The criterion variable was the value of the largest eigenvalue of the correlation matrix.

  14. Survivalism and Public Opinion on Criminality: A Cross-National Analysis of Prostitution

    ERIC Educational Resources Information Center

    Stack, Steven; Adamczyk, Amy; Cao, Liqun

    2010-01-01

    Explanations of variability in public opinion on crime have drawn disproportionately from the literature on specific symbolic orientations including religious fundamentalism and racial prejudice. In contrast, this article hypothesizes that public opinion is linked to the strength of a general cultural axis of nations: survivalism vs.…

  15. Predictors of Employment Outcomes for State-Federal Vocational Rehabilitation Consumers with HIV/AIDS

    ERIC Educational Resources Information Center

    Jung, Youngoh; Schaller, James; Bellini, James

    2010-01-01

    In this study, the authors investigated the effects of demographic, medical, and vocational rehabilitation service variables on employment outcomes of persons living with HIV/AIDS. Binary logistic regression analyses were conducted to determine predictors of employment outcomes using two groups drawn from Rehabilitation Services Administration…

  16. Personal Fables, Narcissism, and Adolescent Adjustment

    ERIC Educational Resources Information Center

    Aalsma, Matthew C.; Lapsley, Daniel K.; Flannery, Daniel J.

    2006-01-01

    The relationship among three personal fables ("omnipotence," "invulnerability," "personal uniqueness"), narcissism, and mental health variables was assessed in a large, cross-sectional sample of adolescents drawn from Grades 6 (n = 94), 8 (n = 223), 10 (n = 142), and 12 (n = 102). Participants responded to the New Personal Fable Scale, the…

  17. College and Adult Reading VIII: The Eighth Yearbook of the North Central Reading Association.

    ERIC Educational Resources Information Center

    Fisher, Joseph A., Ed.

    Drawn from the presentations at the eighteenth and nineteenth annual conferences of the North Central Reading Association, this yearbook includes sections on programs and centers; materials and techniques; evaluation; and professional growth and issues. Papers include: "Successfully Effecting Change on Personality Variables through Academic Skills…

  18. How to Measure Diversity When You Must

    ERIC Educational Resources Information Center

    Budescu, David V.; Budescu, Mia

    2012-01-01

    Racial/ethnic diversity has become an increasingly important variable in the social sciences. Research from multiple disciplines consistently demonstrates the tremendous impact of ethnic diversity on individuals and organizations. Investigators use a variety of measures, and their choices can affect the conclusions that can be drawn and limit the…

  19. Explaining Relationships among Student Outcomes and the School's Physical Environment

    ERIC Educational Resources Information Center

    Tanner, C. Kenneth

    2008-01-01

    This descriptive study investigated the possible effects of selected school design patterns on third-grade students' academic achievement. A reduced regression analysis revealed the effects of school design components (patterns) on ITBS achievement data, after including control variables, for a sample of third-grade students drawn from 24…

  20. Lexical Characteristics of Expressive Vocabulary in Toddlers with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Kover, Sara T.; Weismer, Susan Ellis

    2014-01-01

    Purpose: Vocabulary is a domain of particular challenge for many children with autism spectrum disorder (ASD). Recent research has drawn attention to ways in which lexical characteristics relate to vocabulary acquisition. The current study tested the hypothesis that lexical characteristics account for variability in vocabulary size of young…

  1. Consistency of Children's Inconsistent Preferences Attributable to Novelty

    ERIC Educational Resources Information Center

    Bradbury, Hinton

    1975-01-01

    The analysis of logical and antilogical influences on preference made by Bradbury and Nelson is extended to a consideration of choices by children in kindergarten, Grade 4, and Grade 8. Conclusions are drawn concerning the dependence of intransitive preference on the collative variable of novelty in choice context. (Author/SDH)

  2. School Management and Contingency Theory: An Emerging Perspective.

    ERIC Educational Resources Information Center

    Hanson, E. Mark

    An understanding of the "situational" characteristics of the organizational forces that influence the relationships between environmental, management, and performance variables is now coming to be seen as a key to understanding the management process itself. This paper is a synthesis of the contingency theory literature drawn from the…

  3. Instructional Media Choice: Factors Affecting the Preferences of Distance Education Coordinators

    ERIC Educational Resources Information Center

    Caspi, Avner; Gorsky, Paul

    2005-01-01

    This article examines the impact of several variables on media choice among 51 distance education course coordinators at the Open University of Israel. Hypotheses were drawn from Media Richness Theory (Daft & Lengel, 1984), Social Influence Theory (Fulk, 1993), Media Symbolism (Trevino, Lengel & Daft, 1987), and Experience Account (King…

  4. Early antibiotic administration but not antibody therapy directed against IL-6 improves survival in septic mice predicted to die on basis of high IL-6 levels.

    PubMed

    Vyas, Dinesh; Javadi, Pardis; Dipasco, Peter J; Buchman, Timothy G; Hotchkiss, Richard S; Coopersmith, Craig M

    2005-10-01

    Elevated interleukin (IL)-6 levels correlate with increased mortality following sepsis. IL-6 levels >14,000 pg/ml drawn 6 h after cecal ligation and puncture (CLP) are associated with 100% mortality in ND4 mice, even if antibiotic therapy is initiated 12 h after septic insult. Our first aim was to see whether earlier institution of antibiotic therapy could improve overall survival in septic mice and rescue the subset of animals predicted to die on the basis of high IL-6 levels. Mice (n = 184) were subjected to CLP, had IL-6 levels drawn 6 h later, and then were randomized to receive imipenem, a broad spectrum antimicrobial agent, beginning 6 or 12 h postoperatively. Overall 1-wk survival improved from 25.5 to 35.9% with earlier administration of antibiotics (P < 0.05). In mice with IL-6 levels >14,000 pg/ml, 25% survived if imipenem was started at 6 h, whereas none survived if antibiotics were started later (P < 0.05). On the basis of these results, we examined whether targeted antibody therapy could improve survival in mice with elevated IL-6 levels. A different cohort of mice (n = 54) had blood drawn 6 h after CLP, and then they were randomized to receive either monoclonal anti-IL-6 IgG or irrelevant rat IgG. Anti-IL-6 antibody failed to improve either overall survival or outcome in mice with IL-6 levels >14,000 pg/ml. These results demonstrate that earlier systemic therapy can improve outcome in a subset of mice predicted to die in sepsis, but we are unable to demonstrate any benefit in similar animals using targeted therapy directed at IL-6.

  5. Early antibiotic administration but not antibody therapy directed against IL-6 improves survival in septic mice predicted to die based upon high IL-6 levels

    PubMed Central

    Vyas, Dinesh; Javadi, Pardis; DiPasco, Peter J; Buchman, Timothy G; Hotchkiss, Richard S; Coopersmith, Craig M

    2005-01-01

    Elevated interleukin (IL)-6 levels correlate with increased mortality following sepsis. IL-6 levels >14,000 pg/ml drawn 6 hours following cecal ligation and puncture (CLP) are associated with 100% mortality in ND4 mice, even if antibiotic therapy is initiated 12 hours after the septic insult. The first aim of this study was to see if earlier institution of antibiotic therapy could improve overall survival in septic mice and rescue the subset of animals predicted to die based upon high IL-6 levels. Mice (n=184) were subjected to CLP, had IL-6 levels drawn six hours later and then were randomized to receive imipenem, a broad spectrum antimicrobial agent, beginning six or twelve hours post-operatively. Overall one-week survival improved from 25.5% to 35.9% with earlier administration of antibiotics (p<0.05). In mice with IL-6 levels >14,000 pg/ml, 25% survived if imipenem was started at 6 hours, while none survived if antibiotics were started later (p<0.05). Based upon these results, we examined whether targeted antibody therapy could improve survival in mice with elevated IL-6 levels. A different cohort of mice (n=54) had their blood drawn six hours after CLP and then were randomized to receive either monoclonal anti-IL-6 IgG or irrelevant rat IgG. Anti-IL-6 antibody failed to improve either overall survival or outcome in mice with IL-6 levels >14,000 pg/ml. These results demonstrate that earlier systemic therapy can improve outcome in a subset of mice predicted to die in sepsis, but we are unable to demonstrate any benefit in similar animals using targeted therapy directed at IL-6. PMID:15947070

  6. Learning Probabilities From Random Observables in High Dimensions: The Maximum Entropy Distribution and Others

    NASA Astrophysics Data System (ADS)

    Obuchi, Tomoyuki; Cocco, Simona; Monasson, Rémi

    2015-11-01

    We consider the problem of learning a target probability distribution over a set of N binary variables from the knowledge of the expectation values (with this target distribution) of M observables, drawn uniformly at random. The space of all probability distributions compatible with these M expectation values within some fixed accuracy, called version space, is studied. We introduce a biased measure over the version space, which gives a boost increasing exponentially with the entropy of the distributions and with an arbitrary inverse `temperature' Γ . The choice of Γ allows us to interpolate smoothly between the unbiased measure over all distributions in the version space (Γ =0) and the pointwise measure concentrated at the maximum entropy distribution (Γ → ∞ ). Using the replica method we compute the volume of the version space and other quantities of interest, such as the distance R between the target distribution and the center-of-mass distribution over the version space, as functions of α =(log M)/N and Γ for large N. Phase transitions at critical values of α are found, corresponding to qualitative improvements in the learning of the target distribution and to the decrease of the distance R. However, for fixed α the distance R does not vary with Γ which means that the maximum entropy distribution is not closer to the target distribution than any other distribution compatible with the observable values. Our results are confirmed by Monte Carlo sampling of the version space for small system sizes (N≤ 10).

  7. On the identification of Dragon Kings among extreme-valued outliers

    NASA Astrophysics Data System (ADS)

    Riva, M.; Neuman, S. P.; Guadagnini, A.

    2013-07-01

    Extreme values of earth, environmental, ecological, physical, biological, financial and other variables often form outliers to heavy tails of empirical frequency distributions. Quite commonly such tails are approximated by stretched exponential, log-normal or power functions. Recently there has been an interest in distinguishing between extreme-valued outliers that belong to the parent population of most data in a sample and those that do not. The first type, called Gray Swans by Nassim Nicholas Taleb (often confused in the literature with Taleb's totally unknowable Black Swans), is drawn from a known distribution of the tails which can thus be extrapolated beyond the range of sampled values. However, the magnitudes and/or space-time locations of unsampled Gray Swans cannot be foretold. The second type of extreme-valued outliers, termed Dragon Kings by Didier Sornette, may in his view be sometimes predicted based on how other data in the sample behave. This intriguing prospect has recently motivated some authors to propose statistical tests capable of identifying Dragon Kings in a given random sample. Here we apply three such tests to log air permeability data measured on the faces of a Berea sandstone block and to synthetic data generated in a manner statistically consistent with these measurements. We interpret the measurements to be, and generate synthetic data that are, samples from α-stable sub-Gaussian random fields subordinated to truncated fractional Gaussian noise (tfGn). All these data have frequency distributions characterized by power-law tails with extreme-valued outliers about the tail edges.

  8. Time-lapse culture with morphokinetic embryo selection improves pregnancy and live birth chances and reduces early pregnancy loss: a meta-analysis.

    PubMed

    Pribenszky, Csaba; Nilselid, Anna-Maria; Montag, Markus

    2017-11-01

    Embryo evaluation and selection is fundamental in clinical IVF. Time-lapse follow-up of embryo development comprises undisturbed culture and the application of the visual information to support embryo evaluation. A meta-analysis of randomized controlled trials was carried out to study whether time-lapse monitoring with the prospective use of a morphokinetic algorithm for selection of embryos improves overall clinical outcome (pregnancy, early pregnancy loss, stillbirth and live birth rate) compared with embryo selection based on single time-point morphology in IVF cycles. The meta-analysis of five randomized controlled trials (n = 1637) showed that the application of time-lapse monitoring was associated with a significantly higher ongoing clinical pregnancy rate (51.0% versus 39.9%), with a pooled odds ratio of 1.542 (P < 0.001), significantly lower early pregnancy loss (15.3% versus 21.3%; OR: 0.662; P = 0.019) and a significantly increased live birth rate (44.2% versus 31.3%; OR 1.668; P = 0.009). Difference in stillbirth was not significant between groups (4.7% versus 2.4%). Quality of the evidence was moderate to low owing to inconsistencies across the studies. Selective application and variability were also limitations. Although time-lapse is shown to significantly improve overall clinical outcome, further high-quality evidence is needed before universal conclusions can be drawn. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  9. Evaluating a Multidimensional Reading Comprehension Program and Reconsidering the Lowly Reputation of Tests of Near Transfer

    ERIC Educational Resources Information Center

    Fuchs, Douglas; Hendricks, Emma; Walsh, Meagan E.; Fuchs, Lynn S.; Gilbert, Jennifer K.; Zhang Tracy, Wen; Patton, Samuel, III.; Davis, Nicole; Kim, Wooliya; Elleman, Amy M.; Peng, Peng

    2018-01-01

    We conducted a 14-week experimental study of 2 versions of a relatively comprehensive RC intervention that involved 50 classroom teachers, 15 tutors, and 120 children drawn in equal proportions from grades 3 and 5 in 13 schools in a large urban school district. Students were randomly assigned in equal numbers to the 2 tutoring conditions and a…

  10. Evaluating a Multidimensional Reading Comprehension Program and Reconsidering the Lowly Reputation of Tests of Near-Transfer

    ERIC Educational Resources Information Center

    Fuchs, Douglas; Hendricks, Emma; Walsh, Meagan E.; Fuchs, Lynn S.; Gilbert, Jennifer K.; Zhang Tracy, Wen; Patton, Samuel, III; Davis-Perkins, Nicole; Kim, Wooliya; Elleman, Amy M.; Peng, Peng

    2018-01-01

    We conducted a 14-week experimental study of 2 versions of a relatively comprehensive RC intervention that involved 50 classroom teachers, 15 tutors, and 116 children drawn in equal proportions from grades 3 and 5 in 13 schools in a large urban school district. Students were randomly assigned in equal numbers to the two tutoring conditions and a…

  11. Gender Differences and Public Sector Managers: Women's Perceptions of Equality in State Government.

    ERIC Educational Resources Information Center

    Whitcraft, Carol; Williams, M. Lee

    A study assessed the equality of women managers in 11 of the largest state agencies in Texas. It also investigated the perceptions of men and women managers concerning a variety of work related issues in Texas state government. A stratified random sample of 25 percent of all managers was drawn, and 1,844 responses, representing a 55.5% response…

  12. Effects of Project, Inquiry and Lecture-Demonstration Teaching Methods on Senior Secondary Students' Achievement in Separation of Mixtures Practical Test

    ERIC Educational Resources Information Center

    Sola, Agboola Omowunmi; Ojo, Oloyede Ezekiel

    2007-01-01

    This study assessed and compared the relative effectiveness of three methods for teaching and conducting experiments in separation of mixtures in chemistry. A pre-test, post-test experimental design with a control group was used. Two hundred and thirty three randomly selected Senior Secondary School I (SSS I) chemistry students were drawn from…

  13. A Longitudinal Study of Illinois State Scholarship Commission Monetary Award Recipients, 1967-1974.

    ERIC Educational Resources Information Center

    Boyd, Joseph D.; Fenske, Robert H.

    The present effectiveness and future direction of monetary award programs administered by the Illinois State Scholarship Commission is examined in three surveys. A random sample of 1,000 was drawn from the total number of scholarship recipients during the 1967-68 and 1970-71 academic years; 2,000 from the 1973-74 survey. It is shown that: (1)…

  14. Evaluating Effect of Students' Academic Achievement on Identified Difficult Concepts in Senior Secondary School Biology in Delta State

    ERIC Educational Resources Information Center

    Agboghoroma, Tim E.; Oyovwi, E. O.

    2015-01-01

    This study evaluated the effect of students' academic achievement on identified difficult concepts or topics in Senior Secondary School Biology in Delta State, Nigeria. The study was quasi-experimental and the design was a 2X2 factorial non-randomized pretest-posttest control group design. The sample was drawn from intact classes from four…

  15. Same Sex Attraction, Homophobic Bullying and Mental Health of Young People in Northern Ireland

    ERIC Educational Resources Information Center

    McNamee, Helen; Lloyd, Katrina; Schubotz, Dirk

    2008-01-01

    This article reports on the relationship between same-sex attraction, experience of bullying in school and mental health measured using the 12-item version of the General Health Questionnaire (GHQ12). A random sample of 16 year olds, drawn from the Child Benefit Register, was invited to take part in the 2005 Young Life and Times survey, which is a…

  16. Testing Mediators Hypothesized to Account for the Effects of a Dissonance-Based Eating Disorder Prevention Program over Longer Term Follow-Up

    ERIC Educational Resources Information Center

    Stice, Eric; Marti, C. Nathan; Rohde, Paul; Shaw, Heather

    2011-01-01

    Objective: Test the hypothesis that reductions in thin-ideal internalization and body dissatisfaction mediate the effects of a dissonance-based eating disorder prevention program on reductions in eating disorder symptoms over 1-year follow-up. Method: Data were drawn from a randomized effectiveness trial in which 306 female high school students…

  17. The effects of noise due to random undetected tilts and paleosecular variation on regional paleomagnetic directions

    USGS Publications Warehouse

    Calderone, G.J.; Butler, R.F.

    1991-01-01

    Random tilting of a single paleomagnetic vector produces a distribution of vectors which is not rotationally symmetric about the original vector and therefore not Fisherian. Monte Carlo simulations were performed on two types of vector distributions: 1) distributions of vectors formed by perturbing a single original vector with a Fisher distribution of bedding poles (each defining a tilt correction) and 2) standard Fisher distributions. These simulations demonstrate that inclinations of vectors drawn from both distributions are biased toward shallow inclinations. The Fisher mean direction of the distribution of vectors formed by perturbing a single vector with random undetected tilts is biased toward shallow inclinations, but this bias is insignificant for angular dispersions of bedding poles less than 20??. -from Authors

  18. Optical memory development. Volume 2: Gain-assisted holographic storage media

    NASA Technical Reports Server (NTRS)

    Gange, R. A.; Mezrich, R. S.

    1972-01-01

    Thin deformable films were investigated for use as the storage medium in a holographic optical memory. The research was directed toward solving the problems of material fatigue, selective heat addressing, electrical charging of the film surface and charge patterning by light. A number of solutions to these problems were found but the main conclusion to be drawn from the work is that deformable media which employ heat in the recording process are not satisfactory for use in a high-speed random-access read/write holographic memory. They are, however, a viable approach in applications where either high speed or random-access is not required.

  19. Structural Analysis of Hand Drawn Bumblebee Bombus terrestris Silk.

    PubMed

    Woodhead, Andrea L; Sutherland, Tara D; Church, Jeffrey S

    2016-07-20

    Bombus terrestris, commonly known as the buff-tailed bumblebee, is native to Europe, parts of Africa and Asia. It is commercially bred for use as a pollinator of greenhouse crops. Larvae pupate within a silken cocoon that they construct from proteins produced in modified salivary glands. The amino acid composition and protein structure of hand drawn B. terrestris, silk fibres was investigated through the use of micro-Raman spectroscopy. Spectra were obtained from single fibres drawn from the larvae salivary gland at a rate of 0.14 cm/s. Raman spectroscopy enabled the identification of poly(alanine), poly(alanine-glycine), phenylalanine, tryptophan, and methionine, which is consistent with the results of amino acid analysis. The dominant protein conformation was found to be coiled coil (73%) while the β-sheet content of 10% is, as expected, lower than those reported for hornets and ants. Polarized Raman spectra revealed that the coiled coils were highly aligned along the fibre axis while the β-sheet and random coil components had their peptide carbonyl groups roughly perpendicular to the fibre axis. The protein orientation distribution is compared to those of other natural and recombinant silks. A structural model for the B. terrestris silk fibre is proposed based on these results.

  20. The (Mis)Measurement of Job Performance in Child Welfare Using (Non)Experimental Design

    ERIC Educational Resources Information Center

    Lieberman, Alice A.; Levy, Michelle M.

    2006-01-01

    This commentary explicates two principal arguments against the conclusions drawn by Robin Perry in his article "Do Social Workers Make Better Child Welfare Workers Than Non-Social Workers?" The first concerns the methodology used, whereas the second centers on the measurement of the dependent variable, performance expectation. Considering the…

  1. A Cross-Age Study of Science Student Teachers' Chemistry Attitudes

    ERIC Educational Resources Information Center

    Çalik, Muammer; Ültay, Neslihan; Kolomuç, Ali; Aytar, Ayse

    2015-01-01

    The aim of this study is to investigate the effects of some variables (gender and year of study) on science student teachers' (SSTs) chemistry attitudes. An adapted version of Chemistry Attitudes and Experiences Questionnaire was administered to 983 SSTs drawn from four different universities in the region of Eastern Black Sea, Turkey. Significant…

  2. The Gender Division of Labor in Two-Earner Marriages: Dimensions of Variability and Change.

    ERIC Educational Resources Information Center

    Ferree, Myra Marx

    1991-01-01

    Examined data drawn from representative sample survey of two-earner households (n=382 couples) on division of domestic labor. Concludes that implicitly and explicitly gendered expectations that both husbands and wives bring to thinking about housework play significant role in shaping degree of egalitarianism in practice. (Author/NB)

  3. Non-Intellectual Correlates of Attrition Among Disadvantaged Adults.

    ERIC Educational Resources Information Center

    Wingate, James G.

    The study described in this report was conducted in order to determine the effects of self concept and selected demographic and economic variables on attrition. Data are drawn from a group of 74 disadvantaged adult students who enrolled in a college preparatory program at the Syracuse Educational Opportunity Center (S.E.O.C.). Demographic…

  4. ICCS 2009 User Guide for the International Database. Supplement 4: ICCS 2009 Sampling Stratification Information

    ERIC Educational Resources Information Center

    Brese, Falk; Jung, Michael; Mirazchiyski, Plamen; Schulz, Wolfram; Zuehlke, Olaf

    2011-01-01

    This supplement contains documentation on the explicit and implicit stratification variables included in the International Civic and Citizenship Education Study (ICCS) 2009 data files. The explicit strata are smaller sampling frames, created from the national sampling frames, from which national samples of schools were drawn. The implicit strata…

  5. Network Structural Influences on the Adoption of Evidence-Based Prevention in Communities

    ERIC Educational Resources Information Center

    Fujimoto, Kayo; Valente, Thomas W.; Pentz, Mary Ann

    2009-01-01

    This study examined the impact of key variables in coalition communication networks, centralization and density, on the adoption of evidence-based substance abuse prevention. Data were drawn from a network survey and a corresponding community leader survey that measured leader attitudes and practices toward substance abuse prevention programs. Two…

  6. Simulation of Teacher Demand, Demographics, and Mobility: A Preliminary Report.

    ERIC Educational Resources Information Center

    Baugh, William H.; Stone, Joe A.

    A Markov chain is used to construct a simulation model of the educator labor market in Oregon. The variables crucial to this study, drawn from the University of Southern California faculty planning model, include factors such as appointment rate; age; probability of attaining promotion; retirement, resignation and mortality rates; length of…

  7. Teacher Support, Instructional Practices, Student Motivation, and Mathematics Achievement in High School

    ERIC Educational Resources Information Center

    Yu, Rongrong; Singh, Kusum

    2018-01-01

    The authors examined the relationships among teacher classroom practices, student motivation, and mathematics achievement in high school. The data for this study was drawn from the base-year data of High School Longitudinal Study of 2009. Structural equation modeling method was used to estimate the relationships among variables. The results…

  8. Intra-and-Inter Species Biomass Prediction in a Plantation Forest: Testing the Utility of High Spatial Resolution Spaceborne Multispectral RapidEye Sensor and Advanced Machine Learning Algorithms

    PubMed Central

    Dube, Timothy; Mutanga, Onisimo; Adam, Elhadi; Ismail, Riyad

    2014-01-01

    The quantification of aboveground biomass using remote sensing is critical for better understanding the role of forests in carbon sequestration and for informed sustainable management. Although remote sensing techniques have been proven useful in assessing forest biomass in general, more is required to investigate their capabilities in predicting intra-and-inter species biomass which are mainly characterised by non-linear relationships. In this study, we tested two machine learning algorithms, Stochastic Gradient Boosting (SGB) and Random Forest (RF) regression trees to predict intra-and-inter species biomass using high resolution RapidEye reflectance bands as well as the derived vegetation indices in a commercial plantation. The results showed that the SGB algorithm yielded the best performance for intra-and-inter species biomass prediction; using all the predictor variables as well as based on the most important selected variables. For example using the most important variables the algorithm produced an R2 of 0.80 and RMSE of 16.93 t·ha−1 for E. grandis; R2 of 0.79, RMSE of 17.27 t·ha−1 for P. taeda and R2 of 0.61, RMSE of 43.39 t·ha−1 for the combined species data sets. Comparatively, RF yielded plausible results only for E. dunii (R2 of 0.79; RMSE of 7.18 t·ha−1). We demonstrated that although the two statistical methods were able to predict biomass accurately, RF produced weaker results as compared to SGB when applied to combined species dataset. The result underscores the relevance of stochastic models in predicting biomass drawn from different species and genera using the new generation high resolution RapidEye sensor with strategically positioned bands. PMID:25140631

  9. The Effects of Compensatory Scanning Training on Mobility in Patients with Homonymous Visual Field Defects: Further Support, Predictive Variables and Follow-Up

    PubMed Central

    Melis-Dankers, Bart J. M.; Brouwer, Wiebo H.; Tucha, Oliver; Heutink, Joost

    2016-01-01

    Introduction People with homonymous visual field defects (HVFD) often report difficulty detecting obstacles in the periphery on their blind side in time when moving around. Recently, a randomized controlled trial showed that the InSight-Hemianopia Compensatory Scanning Training (IH-CST) specifically improved detection of peripheral stimuli and avoiding obstacles when moving around, especially in dual task situations. Method The within-group training effects of the previously reported IH-CST are examined in an extended patient group. Performance of patients with HVFD on a pre-assessment, post-assessment and follow-up assessment and performance of a healthy control group are compared. Furthermore, it is examined whether training effects can be predicted by demographic characteristics, variables related to the visual disorder, and neuropsychological test results. Results Performance on both subjective and objective measures of mobility-related scanning was improved after training, while no evidence was found for improvement in visual functions (including visual fields), reading, visual search and dot counting. Self-reported improvement did not correlate with improvement in objective mobility performance. According to the participants, the positive effects were still present six to ten months after training. No demographic characteristics, variables related to the visual disorder, and neuropsychological test results were found to predict the size of training effect, although some inconclusive evidence was found for more improvement in patients with left-sided HVFD than in patients with right-sided HFVD. Conclusion Further support was found for a positive effect of IH-CST on detection of visual stimuli during mobility-related activities specifically. Based on the reports given by patients, these effects appear to be long-term effects. However, no conclusions can be drawn on the objective long-term training effects. PMID:27935973

  10. Biologically-variable rhythmic auditory cues are superior to isochronous cues in fostering natural gait variability in Parkinson's disease.

    PubMed

    Dotov, D G; Bayard, S; Cochen de Cock, V; Geny, C; Driss, V; Garrigue, G; Bardy, B; Dalla Bella, S

    2017-01-01

    Rhythmic auditory cueing improves certain gait symptoms of Parkinson's disease (PD). Cues are typically stimuli or beats with a fixed inter-beat interval. We show that isochronous cueing has an unwanted side-effect in that it exacerbates one of the motor symptoms characteristic of advanced PD. Whereas the parameters of the stride cycle of healthy walkers and early patients possess a persistent correlation in time, or long-range correlation (LRC), isochronous cueing renders stride-to-stride variability random. Random stride cycle variability is also associated with reduced gait stability and lack of flexibility. To investigate how to prevent patients from acquiring a random stride cycle pattern, we tested rhythmic cueing which mimics the properties of variability found in healthy gait (biological variability). PD patients (n=19) and age-matched healthy participants (n=19) walked with three rhythmic cueing stimuli: isochronous, with random variability, and with biological variability (LRC). Synchronization was not instructed. The persistent correlation in gait was preserved only with stimuli with biological variability, equally for patients and controls (p's<0.05). In contrast, cueing with isochronous or randomly varying inter-stimulus/beat intervals removed the LRC in the stride cycle. Notably, the individual's tendency to synchronize steps with beats determined the amount of negative effects of isochronous and random cues (p's<0.05) but not the positive effect of biological variability. Stimulus variability and patients' propensity to synchronize play a critical role in fostering healthier gait dynamics during cueing. The beneficial effects of biological variability provide useful guidelines for improving existing cueing treatments. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Formability analysis of austenitic stainless steel-304 under warm conditions

    NASA Astrophysics Data System (ADS)

    Lade, Jayahari; Singh, Swadesh Kumar; Banoth, Balu Naik; Gupta, Amit Kumar

    2013-12-01

    A warm deep drawing process of austenitic stainless steel-304 (ASS-304) of circular blanks with coupled ther mal analysis is studied in this article. 65 mm blanks were deep drawn at different temperatures and thickness distribution is experimentally measured after cutting the drawn component into two halves. The process is simulated using explicit fin ite element code LS-DYNA. A Barlat 3 parameter model is used in the simulation, as the material is anisotropic up to 30 0°C. Material properties for the simulation are determined at different temperatures using a 5 T UTM coupled with a furn ace. In this analysis constant punch speed and variable blank holder force (BHF) is applied to draw cups without wrinkle.

  12. An instrumental variable random-coefficients model for binary outcomes

    PubMed Central

    Chesher, Andrew; Rosen, Adam M

    2014-01-01

    In this paper, we study a random-coefficients model for a binary outcome. We allow for the possibility that some or even all of the explanatory variables are arbitrarily correlated with the random coefficients, thus permitting endogeneity. We assume the existence of observed instrumental variables Z that are jointly independent with the random coefficients, although we place no structure on the joint determination of the endogenous variable X and instruments Z, as would be required for a control function approach. The model fits within the spectrum of generalized instrumental variable models, and we thus apply identification results from our previous studies of such models to the present context, demonstrating their use. Specifically, we characterize the identified set for the distribution of random coefficients in the binary response model with endogeneity via a collection of conditional moment inequalities, and we investigate the structure of these sets by way of numerical illustration. PMID:25798048

  13. Polynomial chaos expansion with random and fuzzy variables

    NASA Astrophysics Data System (ADS)

    Jacquelin, E.; Friswell, M. I.; Adhikari, S.; Dessombz, O.; Sinou, J.-J.

    2016-06-01

    A dynamical uncertain system is studied in this paper. Two kinds of uncertainties are addressed, where the uncertain parameters are described through random variables and/or fuzzy variables. A general framework is proposed to deal with both kinds of uncertainty using a polynomial chaos expansion (PCE). It is shown that fuzzy variables may be expanded in terms of polynomial chaos when Legendre polynomials are used. The components of the PCE are a solution of an equation that does not depend on the nature of uncertainty. Once this equation is solved, the post-processing of the data gives the moments of the random response when the uncertainties are random or gives the response interval when the variables are fuzzy. With the PCE approach, it is also possible to deal with mixed uncertainty, when some parameters are random and others are fuzzy. The results provide a fuzzy description of the response statistical moments.

  14. Computer simulation of random variables and vectors with arbitrary probability distribution laws

    NASA Technical Reports Server (NTRS)

    Bogdan, V. M.

    1981-01-01

    Assume that there is given an arbitrary n-dimensional probability distribution F. A recursive construction is found for a sequence of functions x sub 1 = f sub 1 (U sub 1, ..., U sub n), ..., x sub n = f sub n (U sub 1, ..., U sub n) such that if U sub 1, ..., U sub n are independent random variables having uniform distribution over the open interval (0,1), then the joint distribution of the variables x sub 1, ..., x sub n coincides with the distribution F. Since uniform independent random variables can be well simulated by means of a computer, this result allows one to simulate arbitrary n-random variables if their joint probability distribution is known.

  15. Vector wind profile gust model

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.

    1981-01-01

    To enable development of a vector wind gust model suitable for orbital flight test operations and trade studies, hypotheses concerning the distributions of gust component variables were verified. Methods for verification of hypotheses that observed gust variables, including gust component magnitude, gust length, u range, and L range, are gamma distributed and presented. Observed gust modulus has been drawn from a bivariate gamma distribution that can be approximated with a Weibull distribution. Zonal and meridional gust components are bivariate gamma distributed. An analytical method for testing for bivariate gamma distributed variables is presented. Two distributions for gust modulus are described and the results of extensive hypothesis testing of one of the distributions are presented. The validity of the gamma distribution for representation of gust component variables is established.

  16. Using Recent BCI Literature to Deepen our Understanding of Clinical Neurofeedback: A Short Review.

    PubMed

    Jeunet, Camille; Lotte, Fabien; Batail, Jean-Marie; Philip, Pierre; Micoulaud Franchi, Jean-Arthur

    2018-05-15

    In their recent paper, Alkoby et al. (2017) provide the readership with an extensive and very insightful review of the factors influencing NeuroFeedback (NF) performance. These factors are drawn from both the NF literature and the Brain-Computer Interface (BCI) literature. Our short review aims to complement Alkoby et al.'s review by reporting recent additions to the BCI literature. The object of this paper is to highlight this literature and discuss its potential relevance and usefulness to better understand the processes underlying NF and further improve the design of clinical trials assessing NF efficacy. Indeed, we are convinced that while NF and BCI are fundamentally different in many ways, both the BCI and NF communities could reach compelling achievements by building upon one another. By reviewing the recent BCI literature, we identified three types of factors that influence BCI performance: task-specific, cognitive/motivational and technology-acceptance-related factors. Since BCIs and NF share a common goal (i.e., learning to modulate specific neurophysiological patterns), similar cognitive and neurophysiological processes are likely to be involved during the training process. Thus, the literature on BCI training may help (1) to deepen our understanding of neurofeedback training processes and (2) to understand the variables that influence the clinical efficacy of NF. This may help to properly assess and/or control the influence of these variables during randomized controlled trials. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

  17. Influence of Host Community on Industrial Relations Practices and Policies: A Survey of Agbara Community and Power Holding Company of Nigeria (PHCN)

    ERIC Educational Resources Information Center

    Chidi, Christopher O.; Shadare, Oluseyi A.

    2011-01-01

    This study investigated the influence of host community on industrial relations practices and policies using Agbara community and Power Holding Company of Nigeria PLC as a case. The study adopted both the qualitative and quantitative methods. A total of 120 samples were drawn from the population using the simple random sampling technique in which…

  18. What Has Happened to Iowa's GED Graduates? A Two-, Five-, and Ten-Year Follow-Up Study. Final Report.

    ERIC Educational Resources Information Center

    Iowa State Dept. of Education, Des Moines. Div. of Community Colleges.

    A longitudinal study was conducted to determine the short-term (2-year), intermediate (5-year), and long-term (10-year) impact of earning a high school equivalency diploma by taking the General Educational Development (GED) Tests in Iowa. The random sample of 2,500 GED graduates was drawn from each time cohort (individuals who had passed the GED…

  19. Measures of Residual Risk with Connections to Regression, Risk Tracking, Surrogate Models, and Ambiguity

    DTIC Science & Technology

    2015-01-07

    vector that helps to manage , predict, and mitigate the risk in the original variable. Residual risk can be exemplified as a quantification of the improved... the random variable of interest is viewed in concert with a related random vector that helps to manage , predict, and mitigate the risk in the original...measures of risk. They view a random variable of interest in concert with an auxiliary random vector that helps to manage , predict and mitigate the risk

  20. Raw and Central Moments of Binomial Random Variables via Stirling Numbers

    ERIC Educational Resources Information Center

    Griffiths, Martin

    2013-01-01

    We consider here the problem of calculating the moments of binomial random variables. It is shown how formulae for both the raw and the central moments of such random variables may be obtained in a recursive manner utilizing Stirling numbers of the first kind. Suggestions are also provided as to how students might be encouraged to explore this…

  1. A Random Variable Related to the Inversion Vector of a Partial Random Permutation

    ERIC Educational Resources Information Center

    Laghate, Kavita; Deshpande, M. N.

    2005-01-01

    In this article, we define the inversion vector of a permutation of the integers 1, 2,..., n. We set up a particular kind of permutation, called a partial random permutation. The sum of the elements of the inversion vector of such a permutation is a random variable of interest.

  2. Natural trophic variability in a large, oligotrophic, near-pristine lake

    USGS Publications Warehouse

    Young, Talia; Jensen, Olaf P.; Weidel, Brian C.; Chandra, Sudeep

    2015-01-01

    Conclusions drawn from stable isotope data can be limited by an incomplete understanding of natural isotopic variability over time and space. We quantified spatial and temporal variability in fish carbon and nitrogen stable isotopes in Lake Hövsgöl, Mongolia, a large, remote, oligotrophic lake with an unusually species-poor fish community. The fish community demonstrated a high degree of trophic level overlap. Variability in δ13C was inversely related to littoral-benthic dependence, with pelagic species demonstrating more δ13C variability than littoral-benthic species. A mixed effects model suggested that space (sampling location) had a greater impact than time (collection year) on both δ13C and δ15N variability. The observed variability in Lake Hövsgöl was generally greater than isotopic variability documented in other large, oligotrophic lakes, similar to isotopic shifts attributed to introduced species, and less than isotopic shifts attributed to anthropogenic chemical changes such as eutrophication. This work complements studies on isotopic variability and changes in other lakes around the world.

  3. A Geometrical Framework for Covariance Matrices of Continuous and Categorical Variables

    ERIC Educational Resources Information Center

    Vernizzi, Graziano; Nakai, Miki

    2015-01-01

    It is well known that a categorical random variable can be represented geometrically by a simplex. Accordingly, several measures of association between categorical variables have been proposed and discussed in the literature. Moreover, the standard definitions of covariance and correlation coefficient for continuous random variables have been…

  4. Virtual active touch using randomly patterned intracortical microstimulation.

    PubMed

    O'Doherty, Joseph E; Lebedev, Mikhail A; Li, Zheng; Nicolelis, Miguel A L

    2012-01-01

    Intracortical microstimulation (ICMS) has promise as a means for delivering somatosensory feedback in neuroprosthetic systems. Various tactile sensations could be encoded by temporal, spatial, or spatiotemporal patterns of ICMS. However, the applicability of temporal patterns of ICMS to artificial tactile sensation during active exploration is unknown, as is the minimum discriminable difference between temporally modulated ICMS patterns. We trained rhesus monkeys in an active exploration task in which they discriminated periodic pulse-trains of ICMS (200 Hz bursts at a 10 Hz secondary frequency) from pulse trains with the same average pulse rate, but distorted periodicity (200 Hz bursts at a variable instantaneous secondary frequency). The statistics of the aperiodic pulse trains were drawn from a gamma distribution with mean inter-burst intervals equal to those of the periodic pulse trains. The monkeys distinguished periodic pulse trains from aperiodic pulse trains with coefficients of variation 0.25 or greater. Reconstruction of movement kinematics, extracted from the activity of neuronal populations recorded in the sensorimotor cortex concurrent with the delivery of ICMS feedback, improved when the recording intervals affected by ICMS artifacts were removed from analysis. These results add to the growing evidence that temporally patterned ICMS can be used to simulate a tactile sense for neuroprosthetic devices.

  5. Parent-teen communication about sex in urban Thai families.

    PubMed

    Rhucharoenpornpanich, Orratai; Chamratrithirong, Aphichat; Fongkaew, Warunee; Miller, Brenda A; Cupp, Pamela K; Rosati, Michael J; Byrnes, Hilary F; Atwood, Katharine A; Chookhare, Warunee

    2012-01-01

    This study describes sexual communication among Thai parents and their teens and identifies variables related to communication about sex in urban Thai families. Data were derived from 420 families whose teenage children ages 13-14 years were randomly selected using the probability proportional to size technique. Interviews were conducted with 1 parent and 1 teenage child in each family. In-depth interviews were also conducted in 30 parents and teens drawn from the same 420 families. Results showed that parents were most likely to talk with their teens about body changes and dating; however, less discussion about sex-related issues, birth control, and HIV/AIDS occurred. More daughters than sons reported frequent discussions with their parents about sex. Parents who believed their teens had been involved in sexual activity were more likely to talk about HIV/AIDS and the difficulty of teenagers having babies, instead of talking about sexual intercourse or when to start having sex. Multiple regression analysis indicated that gender of the child (female), parental religiosity, and parental perception of teen sexual activity were significant predictors of increased sexual communication in Thai families. The findings suggest a need for approaches designed to facilitate communication skills about sex-related issues among Thai parents.

  6. Change in self-esteem predicts depressive symptoms at follow-up after intensive multimodal psychotherapy for major depression.

    PubMed

    Dinger, Ulrike; Ehrenthal, Johannes C; Nikendei, Christoph; Schauenburg, Henning

    2017-09-01

    Reduced self-esteem is a core symptom of depression, but few studies have investigated within-treatment change of self-esteem as a predictor of long-term outcome in depression. This study investigated change in self-esteem during 8 weeks of multimodal, psychodynamically oriented psychotherapy for 40 depressed patients and tested whether it would predict outcome 6 months after termination. Data was drawn from a randomized clinical pilot trial on day-clinic versus inpatient psychotherapy for depression. Findings supported the association between change in self-esteem and follow-up depression severity, even when controlling for within-treatment symptom change. Change in self-esteem was not related to overall symptoms and interpersonal problems at follow-up. Thus, change in self-esteem may be an important variable in preventing relapse for depression. Self-esteem is related to depressive symptoms and interpersonal problems. Improvement of self-esteem during psychotherapy correlates with improvements of symptoms and interpersonal problems. Change of self-esteem during psychotherapy predicts depressive symptoms 6 months after termination of therapy. When treating depressed patients, psychotherapists should work towards an improvement of self-esteem in order to prevent relapse. Copyright © 2017 John Wiley & Sons, Ltd.

  7. Comparing the Happiness Effects of Real and On-Line Friends

    PubMed Central

    Helliwell, John F.; Huang, Haifang

    2013-01-01

    A recent large Canadian survey permits us to compare face-to-face (‘real-life’) and on-line social networks as sources of subjective well-being. The sample of 5,000 is drawn randomly from an on-line pool of respondents, a group well placed to have and value on-line friendships. We find three key results. First, the number of real-life friends is positively correlated with subjective well-being (SWB) even after controlling for income, demographic variables and personality differences. Doubling the number of friends in real life has an equivalent effect on well-being as a 50% increase in income. Second, the size of online networks is largely uncorrelated with subjective well-being. Third, we find that real-life friends are much more important for people who are single, divorced, separated or widowed than they are for people who are married or living with a partner. Findings from large international surveys (the European Social Surveys 2002–2008) are used to confirm the importance of real-life social networks to SWB; they also indicate a significantly smaller value of social networks to married or partnered couples. PMID:24019875

  8. Dental caries in relation to diet, saliva and cariogenic microorganisms in Tanzanians of selected age groups.

    PubMed

    Mazengo, M C; Tenovuo, J; Hausen, H

    1996-06-01

    The relationship between diet and dental caries in a Tanzanian population was studied. Mutans streptococci, lactobacilli, yeasts, salivary flow rate as well as buffer effect were also analyzed. A random sample of 12-, 35-44- and 65- to 74- year olds was drawn from Msongola (rural) and Ukombozi (urban), Dar-es-Salaam. The mean of two 24-h recalls was used for the assessment of food intake. The percentage of those with at least one carious tooth ranged from 30% in the 12-year-olds to 80% in the oldest age group. The mean number of decayed teeth (DT) increased significantly with age (P = 0.000) but was not significantly associated with the area of residence. DT increased significantly (P = 0.048) with the number of snacks per day and was also associated with dietary sucrose (P = 0.025), total carbohydrates (P = 0.002) and fiber (P = 0.002). Among salivary variables lactobacilli (P = 0.000) correlated positively with DT. Our study did not reveal any strong association between total energy intake and dental caries in rural or urban populations in Tanzania but snacking and sucrose intake were significantly associated with caries, in particular in the urban area.

  9. Emperical Tests of Acceptance Sampling Plans

    NASA Technical Reports Server (NTRS)

    White, K. Preston, Jr.; Johnson, Kenneth L.

    2012-01-01

    Acceptance sampling is a quality control procedure applied as an alternative to 100% inspection. A random sample of items is drawn from a lot to determine the fraction of items which have a required quality characteristic. Both the number of items to be inspected and the criterion for determining conformance of the lot to the requirement are given by an appropriate sampling plan with specified risks of Type I and Type II sampling errors. In this paper, we present the results of empirical tests of the accuracy of selected sampling plans reported in the literature. These plans are for measureable quality characteristics which are known have either binomial, exponential, normal, gamma, Weibull, inverse Gaussian, or Poisson distributions. In the main, results support the accepted wisdom that variables acceptance plans are superior to attributes (binomial) acceptance plans, in the sense that these provide comparable protection against risks at reduced sampling cost. For the Gaussian and Weibull plans, however, there are ranges of the shape parameters for which the required sample sizes are in fact larger than the corresponding attributes plans, dramatically so for instances of large skew. Tests further confirm that the published inverse-Gaussian (IG) plan is flawed, as reported by White and Johnson (2011).

  10. Parent-Teen Communication about Sex in Urban Thai Families

    PubMed Central

    Rhucharoenpornpanich, Orratai; Chamratrithirong, Aphichat; Fongkaew, Warunee; Miller, Brenda A.; Cupp, Pamela K.; Roseti, Michael J.; Byrnes, Hilary F.; Atwood, Katharine; Chookhare, Warunee

    2012-01-01

    This study describes sexual communication among Thai parents and their teens and identifies variables related to communication about sex in urban Thai families. Data were derived from 420 families whose teenage children ages 13 – 14 were randomly selected using the probability proportional to size technique. Interviews were conducted with one parent and one teenage child in each family. In-depth interviews were also conducted in 30 parents and teens drawn from the same 420 families. Results showed that parents were most likely to talk with their teens about body changes and dating; however, less discussion about sex-related issues, birth control and HIV/AIDS occurred. More daughters than sons reported frequent discussions with their parents about sex. Parents who believed their teens had been involved in sexual activity were more likely to talk about HIV/AIDS and the difficulty of teenagers having babies, instead of talking about sexual intercourse or when to start having sex. Multiple regression analysis indicated that sex of the child (girls), parental religiosity and parental perception of teen sexual activity were significant predictors of increased sexual communication in Thai families. The findings suggest a need for approaches designed to facilitate communication skills about sex- related issues among Thai parents. PMID:22206411

  11. Method of preparing composite superconducting wire

    DOEpatents

    Verhoeven, John D.; Gibson, Edwin D.; Finnemore, Douglas K.; Ostenson, Jerome E.; Schmidt, Frederick A.; Owen, Charles V.

    1985-08-06

    An improved method of preparing composite multifilament superconducting wire of Nb.sub.3 Sn in a copper matrix which eliminates the necessity of coating the drawn wire with tin. A generalized cylindrical billet of an alloy of copper containing at least 15 weight percent niobium, present in the copper as discrete, randomly distributed and oriented dendritic-shaped particles, is provided with at least one longitudinal opening which is filled with tin to form a composite drawing rod. The drawing rod is then drawn to form a ductile composite multifilament wire containing a filament of tin. The ductile wire containing the tin can then be wound into magnet coils or other devices before heating to diffuse the tin through the wire to react with the niobium forming Nb.sub.3 Sn. Also described is an improved method for making large billets of the copper-niobium alloy by consumable-arc casting.

  12. Evaluation of the statistical evidence for Characteristic Earthquakes in the frequency-magnitude distributions of Sumatra and other subduction zone regions

    NASA Astrophysics Data System (ADS)

    Naylor, M.; Main, I. G.; Greenhough, J.; Bell, A. F.; McCloskey, J.

    2009-04-01

    The Sumatran Boxing Day earthquake and subsequent large events provide an opportunity to re-evaluate the statistical evidence for characteristic earthquake events in frequency-magnitude distributions. Our aims are to (i) improve intuition regarding the properties of samples drawn from power laws, (ii) illustrate using random samples how appropriate Poisson confidence intervals can both aid the eye and provide an appropriate statistical evaluation of data drawn from power-law distributions, and (iii) apply these confidence intervals to test for evidence of characteristic earthquakes in subduction-zone frequency-magnitude distributions. We find no need for a characteristic model to describe frequency magnitude distributions in any of the investigated subduction zones, including Sumatra, due to an emergent skew in residuals of power law count data at high magnitudes combined with a sample bias for examining large earthquakes as candidate characteristic events.

  13. Improved method of preparing composite superconducting wire

    DOEpatents

    Verhoeven, J.D.; Gibson, E.D.; Finnemore, D.K.; Ostenson, J.E.; Schmidt, F.A.; Owen, C.V.

    1979-10-17

    An improved method of preparing composite multifilament superconducting wire of Nb/sub 3/Sn in a copper matrix eliminates the necessity of coating the drawn wire with tin. A generalized cylindrical billet of an alloy of copper containing at least 15 weight percent niobium, present in the copper as discrete, randomly distributed and oriented dendritic-shaped particles, is provided with at least one longitudinal opening which is filled with tin to form a composite drawing rod. The drawing rod is then drawn to form a ductile composite multifilament wire containing a filament of tin. The ductile wire containing the tin can then be wound into magnet coils or other devices before heating to diffuse the tin through the wire to react with the niobium forming Nb/sub 3/Sn. Also described is an improved method for making large billets of the copper-niobium alloy by consumable-arc casting.

  14. PIRLS 2011 User Guide for the International Database. Supplement 4: PIRLS 2011 Sampling Stratification Information

    ERIC Educational Resources Information Center

    Foy, Pierre, Ed.; Drucker, Kathleen T., Ed.

    2013-01-01

    This supplement contains documentation on the explicit and implicit stratification variables included in the PIRLS 2011 data files. The explicit strata are smaller sampling frames, created from the national sampling frames, from which national samples of schools were drawn. The implicit strata are nested within the explicit strata, and were used…

  15. TIMSS 2011 User Guide for the International Database. Supplement 4: TIMSS 2011 Sampling Stratification Information

    ERIC Educational Resources Information Center

    Foy, Pierre, Ed.; Arora, Alka, Ed.; Stanco, Gabrielle M., Ed.

    2013-01-01

    This supplement contains documentation on the explicit and implicit stratification variables included in the TIMSS 2011 data files. The explicit strata are smaller sampling frames, created from the national sampling frames, from which national samples of schools were drawn. The implicit strata are nested within the explicit strata, and were used…

  16. TEAM TRAINING. FINAL TECHNICAL REPORT FEBRUARY 1966-FEBRUARY 1967.

    ERIC Educational Resources Information Center

    BRIGGS, GEORGE E.; JOHNSTON, WILLIAM A.

    THIS IS THE FINAL REPORT ON A FOUR-YEAR PROGRAM OF LABORATORY RESEARCH ON TEAM TRAINING IN A COMBAT INFORMATION CENTER (CIC) CONTEXT. THE RESEARCH LITERATURE ON TEAM TRAINING IS REVIEWED, AND A SET OF CONCLUSIONS IS DRAWN WITH REGARD TO TEAM PERFORMANCE AS A FUNCTION OF TASK, TRAINING, AND COMMUNICATIONS VARIABLES. IN ADDITION, THE IMPLICATIONS…

  17. Influencing Attitudes Regarding Special Class Placement Using a Psychoeducational Report: An Investigation of the Elaboration Likelihood Model.

    ERIC Educational Resources Information Center

    Andrews, Lester W.; Gutkin, Terry B.

    1994-01-01

    Investigates variables drawn from the Elaboration Likelihood Model (ELM) that might be manipulated to enhance the persuasiveness of a psychoeducational report. Results showed teachers in training were more persuaded by reports with high message quality. Findings are discussed in terms of the ELM and professional school psychology practice. (RJM)

  18. What Pictures Can and Can't Do for Children's Story Understanding.

    ERIC Educational Resources Information Center

    Meringoff, Laurene K.

    Contrasts between children's visualization and understanding of a filmed story and of a story in print are drawn in the introduction of this symposium paper. Discussion then briefly focuses on variables related to studying effects of story pictures on viewers, such as the story-line, audience characteristics, and the coordination of story modality…

  19. THE STRUCTURE OF VARIATION AND ITS INFLUENCE ON THE ESTIMATION OF STATUS: INDICATORS OF CONDITION OF LAKES IN THE NORTHEAST, U.S.A.

    EPA Science Inventory

    One goal of regional-scale sample surveys is to estimate the status of a resource of interest from a statistically drawn representative sample of that resource. An expression of status is a frequency distribution of indicator scores capturing the variability of the attributes of...

  20. A Comparative Study on Perceived Effects of Communication Networks in Acquiring International Orientations.

    ERIC Educational Resources Information Center

    Haavelsrud, Magnus

    A study was designed to test the hypothesis that different communication stages between nations--primitive, traditional, modern, and neomodern--provide important variables for explaining differences in pre-adults' conception of war in different countries. Although the two samples used in the study were drawn from two cultures which fall into the…

  1. Paying for Retirement: Sex Differences in Inclusion in Employer-Provided Retirement Plans

    ERIC Educational Resources Information Center

    Wright, Rosemary

    2012-01-01

    Purpose: This study examines sex differences among Baby Boom workers in the likelihood of coverage by an employer-provided retirement plan. Design and Methods: This study used a sample of Baby Boom workers drawn from the 2009 Current Population Survey. Independent variables were selected to replicate as closely as possible those in two 1995…

  2. How Old Am I? Perceived Age in Middle and Later Life

    ERIC Educational Resources Information Center

    Ward, Russell A.

    2010-01-01

    Literatures on perceived age and developmental issues in middle and later life are joined in analyzing perceived age and its implications for well-being. Respondents aged 40-74 (N = 2,696) are drawn from the national MIDUS survey, containing developmental variables such as personal growth and insight into past. People generally "feel" ("felt age")…

  3. High School Counselors' Perceived Self-Efficacy and Relationships with Actual and Preferred Job Activities

    ERIC Educational Resources Information Center

    Jellison, Vickie Dawn

    2013-01-01

    The purpose of this research was to explore the relationship between School Counselor self-efficacy, role definition and actual and preferred school counseling activities in a sample drawn from a population of school counselors. To measure these variables, the School Counselor Self-Efficacy Scale (SCSE) and the School Counselor Activity Rating…

  4. Investigation of Profiles of Risk Factors for Adolescent Psychopathology: A Person-Centered Approach

    ERIC Educational Resources Information Center

    Parra, Gilbert R.; DuBois, David L.; Sher, Kenneth J.

    2006-01-01

    Latent variable mixture modeling was used to identify subgroups of adolescents with distinct profiles of risk factors from individual, family, peer, and broader contextual domains. Data were drawn from the National Longitudinal Study of Adolescent Health. Four-class models provided the most theoretically meaningful solutions for both 7th (n = 907;…

  5. The coverage of a random sample from a biological community.

    PubMed

    Engen, S

    1975-03-01

    A taxonomic group will frequently have a large number of species with small abundances. When a sample is drawn at random from this group, one is therefore faced with the problem that a large proportion of the species will not be discovered. A general definition of quantitative measures of "sample coverage" is proposed, and the problem of statistical inference is considered for two special cases, (1) the actual total relative abundance of those species that are represented in the sample, and (2) their relative contribution to the information index of diversity. The analysis is based on a extended version of the negative binomial species frequency model. The results are tabulated.

  6. Multilevel Model Prediction

    ERIC Educational Resources Information Center

    Frees, Edward W.; Kim, Jee-Seon

    2006-01-01

    Multilevel models are proven tools in social research for modeling complex, hierarchical systems. In multilevel modeling, statistical inference is based largely on quantification of random variables. This paper distinguishes among three types of random variables in multilevel modeling--model disturbances, random coefficients, and future response…

  7. A person based formula for allocating commissioning funds to general practices in England: development of a statistical model.

    PubMed

    Dixon, Jennifer; Smith, Peter; Gravelle, Hugh; Martin, Steve; Bardsley, Martin; Rice, Nigel; Georghiou, Theo; Dusheiko, Mark; Billings, John; Lorenzo, Michael De; Sanderson, Colin

    2011-11-22

    To develop a formula for allocating resources for commissioning hospital care to all general practices in England based on the health needs of the people registered in each practice Multivariate prospective statistical models were developed in which routinely collected electronic information from 2005-6 and 2006-7 on individuals and the areas in which they lived was used to predict their costs of hospital care in the next year, 2007-8. Data on individuals included all diagnoses recorded at any inpatient admission. Models were developed on a random sample of 5 million people and validated on a second random sample of 5 million people and a third sample of 5 million people drawn from a random sample of practices. All general practices in England as of 1 April 2007. All NHS inpatient admissions and outpatient attendances for individuals registered with a general practice on that date. All individuals registered with a general practice in England at 1 April 2007. Power of the statistical models to predict the costs of the individual patient or each practice's registered population for 2007-8 tested with a range of metrics (R(2) reported here). Comparisons of predicted costs in 2007-8 with actual costs incurred in the same year were calculated by individual and by practice. Models including person level information (age, sex, and ICD-10 codes diagnostic recorded) and a range of area level information (such as socioeconomic deprivation and supply of health facilities) were most predictive of costs. After accounting for person level variables, area level variables added little explanatory power. The best models for resource allocation could predict upwards of 77% of the variation in costs at practice level, and about 12% at the person level. With these models, the predicted costs of about a third of practices would exceed or undershoot the actual costs by 10% or more. Smaller practices were more likely to be in these groups. A model was developed that performed well by international standards, and could be used for allocations to practices for commissioning. The best formulas, however, could predict only about 12% of the variation in next year's costs of most inpatient and outpatient NHS care for each individual. Person-based diagnostic data significantly added to the predictive power of the models.

  8. Randomly correcting model errors in the ARPEGE-Climate v6.1 component of CNRM-CM: applications for seasonal forecasts

    NASA Astrophysics Data System (ADS)

    Batté, Lauriane; Déqué, Michel

    2016-06-01

    Stochastic methods are increasingly used in global coupled model climate forecasting systems to account for model uncertainties. In this paper, we describe in more detail the stochastic dynamics technique introduced by Batté and Déqué (2012) in the ARPEGE-Climate atmospheric model. We present new results with an updated version of CNRM-CM using ARPEGE-Climate v6.1, and show that the technique can be used both as a means of analyzing model error statistics and accounting for model inadequacies in a seasonal forecasting framework.The perturbations are designed as corrections of model drift errors estimated from a preliminary weakly nudged re-forecast run over an extended reference period of 34 boreal winter seasons. A detailed statistical analysis of these corrections is provided, and shows that they are mainly made of intra-month variance, thereby justifying their use as in-run perturbations of the model in seasonal forecasts. However, the interannual and systematic error correction terms cannot be neglected. Time correlation of the errors is limited, but some consistency is found between the errors of up to 3 consecutive days.These findings encourage us to test several settings of the random draws of perturbations in seasonal forecast mode. Perturbations are drawn randomly but consistently for all three prognostic variables perturbed. We explore the impact of using monthly mean perturbations throughout a given forecast month in a first ensemble re-forecast (SMM, for stochastic monthly means), and test the use of 5-day sequences of perturbations in a second ensemble re-forecast (S5D, for stochastic 5-day sequences). Both experiments are compared in the light of a REF reference ensemble with initial perturbations only. Results in terms of forecast quality are contrasted depending on the region and variable of interest, but very few areas exhibit a clear degradation of forecasting skill with the introduction of stochastic dynamics. We highlight some positive impacts of the method, mainly on Northern Hemisphere extra-tropics. The 500 hPa geopotential height bias is reduced, and improvements project onto the representation of North Atlantic weather regimes. A modest impact on ensemble spread is found over most regions, which suggests that this method could be complemented by other stochastic perturbation techniques in seasonal forecasting mode.

  9. Combinatorial Statistics on Trees and Networks

    DTIC Science & Technology

    2010-09-29

    interaction graph is drawn from the Erdos- Renyi , G(n,p), where each edge is present independently with probability p. For this model we establish a double...special interest is the behavior of Gibbs sampling on the Erdos- Renyi random graph G{n, d/n), where each edge is chosen independently with...which have no counterparts in the coloring setting. Our proof presented here exploits in novel ways the local treelike structure of Erdos- Renyi

  10. Mean convergence theorems and weak laws of large numbers for weighted sums of random variables under a condition of weighted integrability

    NASA Astrophysics Data System (ADS)

    Ordóñez Cabrera, Manuel; Volodin, Andrei I.

    2005-05-01

    From the classical notion of uniform integrability of a sequence of random variables, a new concept of integrability (called h-integrability) is introduced for an array of random variables, concerning an array of constantsE We prove that this concept is weaker than other previous related notions of integrability, such as Cesàro uniform integrability [Chandra, Sankhya Ser. A 51 (1989) 309-317], uniform integrability concerning the weights [Ordóñez Cabrera, Collect. Math. 45 (1994) 121-132] and Cesàro [alpha]-integrability [Chandra and Goswami, J. Theoret. ProbabE 16 (2003) 655-669]. Under this condition of integrability and appropriate conditions on the array of weights, mean convergence theorems and weak laws of large numbers for weighted sums of an array of random variables are obtained when the random variables are subject to some special kinds of dependence: (a) rowwise pairwise negative dependence, (b) rowwise pairwise non-positive correlation, (c) when the sequence of random variables in every row is [phi]-mixing. Finally, we consider the general weak law of large numbers in the sense of Gut [Statist. Probab. Lett. 14 (1992) 49-52] under this new condition of integrability for a Banach space setting.

  11. Mind-Body Interventions for Irritable Bowel Syndrome Patients in the Chinese Population: a Systematic Review and Meta-Analysis.

    PubMed

    Wang, Weidong; Wang, Fang; Fan, Feng; Sedas, Ana Cristina; Wang, Jian

    2017-04-01

    The aim of this study is to identify and assess evidence related to the efficacy of mind-body interventions on irritable bowel syndrome (IBS) in the Chinese population. Drawn from Chinese databases, nine RCTs and three Q-E studies were included in the systematic review. The methodological quality of RCTs was evaluated based on the following criteria: adequate sequence generation, allocation concealment, blinding, completeness of outcome data, selective reporting, and other potential biases. For continuous variables, the effect size (ES) was determined by calculating the standardized mean difference between groups. For dichotomous variables, the ES was determined by calculating the risk ratio (RR) between groups. Given the heterogeneity between the trials and the small number of studies included, both random effects and fixed effects models were used. The inverse variance method was used for pooling. Statistical analyses were performed using Review Manager version 5.0. The total number of papers identified was 710: 462 from English language databases and 248 from Chinese language databases. Twelve studies met our eligibility criteria. Among the studies selected, three were Q-E studies the rest RCTs. Two studies described the randomization process. None of the studies reported allocation concealment nor blinding. Seven studies reported no dropouts. One of the studies mentioned the total amount of dropouts; though the reason for dropping out was not referenced. The other four studies did not clearly report dropouts. With the exception of three studies, there was inadequate information to determine biased reporting for the majority; the level of risk for bias in these studies is unclear. Finally, six meta-analyses were performed. One was conducted with four randomized controlled trials (RCTs) that used cure rate as outcome measures to evaluate gastrointestinal (GI) symptoms, which suggested that mind-body interventions were effective in improving GI symptoms (random effects model: RR = 1.08; 95 % CI 1.01 to 1.17; fixed effects model: RR = 1.07; 95 % CI 1.01 to 1.12). The remaining five were conducted in three RCTs, which suggested that mind-body interventions were effective in improving several aspects of quality of life, including interference with activity (random effects and fixed effects models: SMD = 0.64; 95 % CI 0.41 to 0.86), body image (random effects model: SMD = 0.36; 95 % CI 0.06 to 0.67; fixed effects model: SMD = 0.33; 95 % CI 0.11 to 0.55), health worry (random effects and fixed effects models: SMD = 0.67; 95 % CI 0.44 to 0.90), food avoidance (random effects and fixed effects models: SMD = 0.45; 95 % CI 0.23 to 0.68), and social reaction (random effects model: SMD = 0.79; 95 % CI 0.47 to 1.12; fixed effects model: SMD = 0.78; 95 % CI 0.55 to 1.01), as measured by Irritable Bowel Syndrome Quality of Life Questionnaire ( IBS-QOL). Mind-body interventions may have the potential to improve GI symptoms in Chinese patients with IBS. The improvement of GI symptoms was also accompanied with the improvement of various outcomes, including depression, anxiety, and quality of life, just to mention a few. However, the published studies generally had significant methodological limitations. Future clinical trials with rigorous research design are needed in this field. More studies focusing on the mind-body interventions originated in China, such as tai chi and qi gong should be encouraged.

  12. Visualizing Spatially Varying Distribution Data

    NASA Technical Reports Server (NTRS)

    Kao, David; Luo, Alison; Dungan, Jennifer L.; Pang, Alex; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    Box plot is a compact representation that encodes the minimum, maximum, mean, median, and quarters information of a distribution. In practice, a single box plot is drawn for each variable of interest. With the advent of more accessible computing power, we are now facing the problem of visual icing data where there is a distribution at each 2D spatial location. Simply extending the box plot technique to distributions over 2D domain is not straightforward. One challenge is reducing the visual clutter if a box plot is drawn over each grid location in the 2D domain. This paper presents and discusses two general approaches, using parametric statistics and shape descriptors, to present 2D distribution data sets. Both approaches provide additional insights compared to the traditional box plot technique

  13. Memory for temporally dynamic scenes.

    PubMed

    Ferguson, Ryan; Homa, Donald; Ellis, Derek

    2017-07-01

    Recognition memory was investigated for individual frames extracted from temporally continuous, visually rich film segments of 5-15 min. Participants viewed a short clip from a film in either a coherent or a jumbled order, followed by a recognition test of studied frames. Foils came either from an earlier or a later part of the film (Experiment 1) or from deleted segments selected from random cuts of varying duration (0.5 to 30 s) within the film itself (Experiment 2). When the foils came from an earlier or later part of the film (Experiment 1), recognition was excellent, with the hit rate far exceeding the false-alarm rate (.78 vs. 18). In Experiment 2, recognition was far worse, with the hit rate (.76) exceeding the false-alarm rate only for foils drawn from the longest cuts (15 and 30 s) and matching the false-alarm rate for the 5 s segments. When the foils were drawn from the briefest cuts (0.5 and 1.0 s), the false-alarm rate exceeded the hit rate. Unexpectedly, jumbling had no effect on recognition in either experiment. These results are consistent with the view that memory for complex visually temporal events is excellent, with the integrity unperturbed by disruption of the global structure of the visual stream. Disruption of memory was observed only when foils were drawn from embedded segments of duration less than 5 s, an outcome consistent with the view that memory at these shortest durations are consolidated with expectations drawn from the previous stream.

  14. Memory Support Strategies and Bundles: A Pathway to Improving Cognitive Therapy for Depression?

    PubMed Central

    Dong, Lu; Lee, Jason Y.; Harvey, Allison G.

    2017-01-01

    Objective Therapist use of memory support (MS) alongside treatment-as-usual, with the goal of enhancing patient recall of treatment contents, has been of recent interest as a novel pathway to improve treatment outcome. The Memory Support Intervention involves treatment providers’ using eight specific MS strategies to promote patient memory for treatment. The present study examines to what extent therapist use of MS strategies and bundles improves patient recall of treatment contents and treatment outcome. Methods The data were drawn from a pilot randomized controlled trial reported elsewhere. Participants were 48 adults (mean age = 44.27 years, 29 females) with major depressive disorder (MDD), randomized to receive 14 sessions of either CT+Memory Support (n = 25) or CT-as-usual (n = 23). Therapist use of MS was coded using the Memory Support Rating Scale. Patient memory and treatment outcomes were assessed at baseline, mid-treatment (patient recall only), post-treatment, and 6-month follow-up. Results Participants in CT+Memory Support received significantly higher amount of MS relative to CT-as-usual. Though not reaching statistical significance, small-to-medium effects were observed between MS strategies and patient recall in the expected direction. Although MS variables were not significantly associated with changes in continuous depressive symptoms, MS was associated with better global functioning. MS also exhibited small to medium effects on treatment response and recurrence in the expected direction but not on remission, though these effects did not reach statistical significance. Conclusions These results provide initial empirical evidence supporting an active method for therapists to implement MS strategies. PMID:28221056

  15. Economic Evaluation of Frequent Home Nocturnal Hemodialysis Based on a Randomized Controlled Trial

    PubMed Central

    Tonelli, Marcello; Pauly, Robert; Walsh, Michael; Culleton, Bruce; So, Helen; Hemmelgarn, Brenda; Manns, Braden

    2014-01-01

    Provider and patient enthusiasm for frequent home nocturnal hemodialysis (FHNHD) has been renewed; however, the cost-effectiveness of this technique is unknown. We performed a cost-utility analysis of FHNHD compared with conventional hemodialysis (CvHD; 4 hours three times per week) from a health payer perspective over a lifetime horizon using patient information from the Alberta NHD randomized controlled trial. Costs, including training costs, were obtained using microcosting and administrative data (CAN$2012). We determined the incremental cost per quality-adjusted life year (QALY) gained. Robustness was assessed using scenario, sensitivity, and probabilistic sensitivity analyses. Compared with CvHD (61% in-center, 14% satellite, and 25% home dialysis), FHNHD led to incremental cost savings (−$6700) and an additional 0.38 QALYs. In sensitivity analyses, when the annual probability of technique failure with FHNHD increased from 7.6% (reference case) to ≥19%, FHNHD became unattractive (>$75,000/QALY). The cost/QALY gained became $13,000 if average training time for FHNHD increased from 3.7 to 6 weeks. In scenarios with alternate comparator modalities, FHNHD remained dominant compared with in-center CvHD; cost/QALYs gained were $18,500, $198,000, and $423,000 compared with satellite CvHD, home CvHD, and peritoneal dialysis, respectively. In summary, FHNHD is attractive compared with in-center CvHD in this cohort. However, the attractiveness of FHNHD varies by technique failure rate, training time, and dialysis modalities from which patients are drawn, and these variables should be considered when establishing FHNHD programs. PMID:24231665

  16. Structural Analysis of Hand Drawn Bumblebee Bombus terrestris Silk

    PubMed Central

    Woodhead, Andrea L.; Sutherland, Tara D.; Church, Jeffrey S.

    2016-01-01

    Bombus terrestris, commonly known as the buff-tailed bumblebee, is native to Europe, parts of Africa and Asia. It is commercially bred for use as a pollinator of greenhouse crops. Larvae pupate within a silken cocoon that they construct from proteins produced in modified salivary glands. The amino acid composition and protein structure of hand drawn B. terrestris, silk fibres was investigated through the use of micro-Raman spectroscopy. Spectra were obtained from single fibres drawn from the larvae salivary gland at a rate of 0.14 cm/s. Raman spectroscopy enabled the identification of poly(alanine), poly(alanine-glycine), phenylalanine, tryptophan, and methionine, which is consistent with the results of amino acid analysis. The dominant protein conformation was found to be coiled coil (73%) while the β-sheet content of 10% is, as expected, lower than those reported for hornets and ants. Polarized Raman spectra revealed that the coiled coils were highly aligned along the fibre axis while the β-sheet and random coil components had their peptide carbonyl groups roughly perpendicular to the fibre axis. The protein orientation distribution is compared to those of other natural and recombinant silks. A structural model for the B. terrestris silk fibre is proposed based on these results. PMID:27447623

  17. Qualitatively Assessing Randomness in SVD Results

    NASA Astrophysics Data System (ADS)

    Lamb, K. W.; Miller, W. P.; Kalra, A.; Anderson, S.; Rodriguez, A.

    2012-12-01

    Singular Value Decomposition (SVD) is a powerful tool for identifying regions of significant co-variability between two spatially distributed datasets. SVD has been widely used in atmospheric research to define relationships between sea surface temperatures, geopotential height, wind, precipitation and streamflow data for myriad regions across the globe. A typical application for SVD is to identify leading climate drivers (as observed in the wind or pressure data) for a particular hydrologic response variable such as precipitation, streamflow, or soil moisture. One can also investigate the lagged relationship between a climate variable and the hydrologic response variable using SVD. When performing these studies it is important to limit the spatial bounds of the climate variable to reduce the chance of random co-variance relationships being identified. On the other hand, a climate region that is too small may ignore climate signals which have more than a statistical relationship to a hydrologic response variable. The proposed research seeks to identify a qualitative method of identifying random co-variability relationships between two data sets. The research identifies the heterogeneous correlation maps from several past results and compares these results with correlation maps produced using purely random and quasi-random climate data. The comparison identifies a methodology to determine if a particular region on a correlation map may be explained by a physical mechanism or is simply statistical chance.

  18. Effectiveness of Parent-Child Mediation in Improving Family Functioning and Reducing Adolescent Problem Behavior: Results from a Pilot Randomized Controlled Trial.

    PubMed

    Tucker, Joan S; Edelen, Maria Orlando; Huang, Wenjing

    2017-03-01

    Parent-child mediation programs are intended to resolve or manage disputes and improve family functioning, but rigorous evaluations of their effectiveness are lacking. Families referred to a community-based mediation program (N = 111) were randomized to an intervention or wait-list control group, and completed three surveys over a 12-week period. With the exception of parent-reported child delinquency (which decreased more in the intervention group), this evaluation provides little support for the short-term effectiveness of parent-child mediation for improving family functioning and reducing child problem behaviors in general. Given that this is the first randomized controlled trial of a parent-child mediation program, additional evaluations involving larger samples and longer follow-ups are needed before firm conclusions can be drawn about the effectiveness of this intervention.

  19. A Meta-Analysis of Depressive Symptom Outcomes in Randomized, Controlled Trials for PTSD.

    PubMed

    Ronconi, Julia McDougal; Shiner, Brian; Watts, Bradley V

    2015-07-01

    Posttraumatic stress disorder (PTSD) often co-occurs with depression. Current PTSD practice guidelines lack specific guidance for clinicians regarding the treatment of depressive symptoms. We conducted a meta-analysis of all randomized, placebo-controlled trials for PTSD therapies focusing on depression outcomes to inform clinicians about effective treatment options for depressive symptoms associated with PTSD. We searched literature databases for randomized, controlled clinical trials of any treatment for PTSD published between 1980 and 2013. We selected articles in which all subjects were adults with a diagnosis of PTSD based on the Diagnostic and Statistical Manual of Mental Disorders criteria, and valid PTSD and depressive symptom measures were reported. The sample consisted of 116 treatment comparisons drawn from 93 manuscripts. Evidence-based PTSD treatments are effective for comorbid depressive symptoms. Existing PTSD treatments work as well for comorbid depressive symptoms as they do for PTSD symptoms.

  20. Deterministic multidimensional nonuniform gap sampling.

    PubMed

    Worley, Bradley; Powers, Robert

    2015-12-01

    Born from empirical observations in nonuniformly sampled multidimensional NMR data relating to gaps between sampled points, the Poisson-gap sampling method has enjoyed widespread use in biomolecular NMR. While the majority of nonuniform sampling schemes are fully randomly drawn from probability densities that vary over a Nyquist grid, the Poisson-gap scheme employs constrained random deviates to minimize the gaps between sampled grid points. We describe a deterministic gap sampling method, based on the average behavior of Poisson-gap sampling, which performs comparably to its random counterpart with the additional benefit of completely deterministic behavior. We also introduce a general algorithm for multidimensional nonuniform sampling based on a gap equation, and apply it to yield a deterministic sampling scheme that combines burst-mode sampling features with those of Poisson-gap schemes. Finally, we derive a relationship between stochastic gap equations and the expectation value of their sampling probability densities. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Effectiveness of Parent-Child Mediation in Improving Family Functioning and Reducing Adolescent Problem Behavior: Results from a Pilot Randomized Controlled Trial

    PubMed Central

    Tucker, Joan S.; Edelen, Maria Orlando; Huang, Wenjing

    2016-01-01

    Parent-child mediation programs are intended to resolve or manage disputes and improve family functioning, but rigorous evaluations of their effectiveness are lacking. Families referred to a community-based mediation program (N=111) were randomized to an intervention or wait-list control group, and completed three surveys over a 12-week period. With the exception of parent-reported child delinquency (which decreased more in the intervention group), this evaluation provides little support for the short-term effectiveness of parent-child mediation for improving family functioning and reducing child problem behaviors in general. Given that this is the first randomized controlled trial of a parent-child mediation program, additional evaluations involving larger samples and longer follow-ups are needed before firm conclusions can be drawn about the effectiveness of this intervention. PMID:26762375

  2. Mixed effects of geolocators on reproduction and survival of Cerulean Warblers, a canopy-dwelling, long-distance migrant

    Treesearch

    Douglas W. Raybuck; Jeffrey L. Larkin; Scott H. Stoleson; Than J. Boves

    2017-01-01

    Light-level geolocators, miniature devices used for tracking avian migration over the full annual cycle, are being widely deployed on small migratory passerines. However, the effects of carrying geolocators on the breeding biology of songbirds are unclear, and variable species- and guild-specific conclusions have been drawn regarding their effects on return rates (...

  3. Health Characteristics as Precursors of Substance Abuse in Puerto Rican Adolescents.

    ERIC Educational Resources Information Center

    Haran, Elizabeth M.; And Others

    In a longitudinal study of precursors of drug usage, data collected in 1968 on health variables was related to substance usage patterns obtained in 1975-76. Some 657 young Puerto Ricans were interviewed for this study, drawn from a pool of about 5,000 questionnaired in 1968. The major findings were that the health factors associated with drug…

  4. The Changing Contours of the Psychological Contract: Unpacking Context and Circumstances of Breach

    ERIC Educational Resources Information Center

    Pate, Judy

    2006-01-01

    Purpose: The purpose of this paper is to propose a processual framework of psychological contract breach, which maps holistically the interactions among concepts drawn from the trust and justice literature. However, the price of a holistic picture is frequently a lack of depth of analysis of any single variable, and consequently the second part of…

  5. Variability in vegetation and surface fuels across mixed-conifer-dominated landscapes with over 40 years of natural fire

    Treesearch

    Brandon M. Collins; Jamie M. Lydersen; Danny L. Fry; Katherine Wilkin; Tadashi Moody; Scott L. Stephens

    2016-01-01

    Studies of historical fire and vegetation conditions in dry conifer forests have demonstrated a high degree of heterogeneity across landscapes. However, there is a limit to the amount of inference that can be drawn from historical fire reconstructions. Contemporary "reference" landscapes may be able to provide information that is not available from historical...

  6. The Relationship between Child Abuse, Parental Divorce, and Lifetime Mental Disorders and Suicidality in a Nationally Representative Adult Sample

    ERIC Educational Resources Information Center

    Afifi, Tracie O.; Boman, Jonathan; Fleisher, William; Sareen, Jitender

    2009-01-01

    Objectives: To determine how the experiences of child abuse and parental divorce are related to long-term mental health outcomes using a nationally representative adult sample after adjusting for sociodemographic variables and parental psychopathology. Methods: Data were drawn from the National Comorbidity Survey (NCS, n=5,877; age 15-54 years;…

  7. Adjustment Problems in the Family and School Contexts, Attitude towards Authority, and Violent Behavior at School in Adolescence

    ERIC Educational Resources Information Center

    Ochoa, Gonzalo Musitu; Lopez, Estefania Estevez; Emler, Nicholas P.

    2007-01-01

    This study analyzed the role of different but interrelated variables in the family and school contexts in relation to problems of violent behavior at school during adolescence. Participants were 1,068 students aged 11 to 16 (47% male) drawn from secondary schools in the Valencian Community (Spain). Statistical analyses were carried out using…

  8. Research of trace metals as markers of entry pathways in combined sewers.

    PubMed

    Gounou, C; Varrault, G; Amedzro, K; Gasperi, J; Moilleron, R; Garnaud, S; Chebbo, G

    2011-01-01

    Combined sewers receive high toxic trace metal loads emitted by various sources, such as traffic, industry, urban heating and building materials. During heavy rain events, Combined Sewer Overflows (CSO) can occur and, if so, are discharged directly into the aquatic system and therefore could have an acute impact on receiving waters. In this study, the concentrations of 18 metals have been measured in 89 samples drawn from the three pollutant Entry Pathways in Combined Sewers (EPCS): i) roof runoff, ii) street runoff, and iii) industrial and domestic effluents and also drawn from sewer deposits (SD). The aim of this research is to identify metallic markers for each EPCS; the data matrix was submitted to principal component analysis in order to determine metallic markers for the three EPCS and SD. This study highlights the fact that metallic content variability across samples from different EPCS and SD exceeds the spatio-temporal variability of samples from the same EPCS. In the catchment studied here, the most valuable EPCS and SD markers are lead, sodium, boron, antimony and zinc; these markers could be used in future studies to identify the contributions of each EPCS to CSO metallic loads.

  9. Design approaches to experimental mediation☆

    PubMed Central

    Pirlott, Angela G.; MacKinnon, David P.

    2016-01-01

    Identifying causal mechanisms has become a cornerstone of experimental social psychology, and editors in top social psychology journals champion the use of mediation methods, particularly innovative ones when possible (e.g. Halberstadt, 2010, Smith, 2012). Commonly, studies in experimental social psychology randomly assign participants to levels of the independent variable and measure the mediating and dependent variables, and the mediator is assumed to causally affect the dependent variable. However, participants are not randomly assigned to levels of the mediating variable(s), i.e., the relationship between the mediating and dependent variables is correlational. Although researchers likely know that correlational studies pose a risk of confounding, this problem seems forgotten when thinking about experimental designs randomly assigning participants to levels of the independent variable and measuring the mediator (i.e., “measurement-of-mediation” designs). Experimentally manipulating the mediator provides an approach to solving these problems, yet these methods contain their own set of challenges (e.g., Bullock, Green, & Ha, 2010). We describe types of experimental manipulations targeting the mediator (manipulations demonstrating a causal effect of the mediator on the dependent variable and manipulations targeting the strength of the causal effect of the mediator) and types of experimental designs (double randomization, concurrent double randomization, and parallel), provide published examples of the designs, and discuss the strengths and challenges of each design. Therefore, the goals of this paper include providing a practical guide to manipulation-of-mediator designs in light of their challenges and encouraging researchers to use more rigorous approaches to mediation because manipulation-of-mediator designs strengthen the ability to infer causality of the mediating variable on the dependent variable. PMID:27570259

  10. Design approaches to experimental mediation.

    PubMed

    Pirlott, Angela G; MacKinnon, David P

    2016-09-01

    Identifying causal mechanisms has become a cornerstone of experimental social psychology, and editors in top social psychology journals champion the use of mediation methods, particularly innovative ones when possible (e.g. Halberstadt, 2010, Smith, 2012). Commonly, studies in experimental social psychology randomly assign participants to levels of the independent variable and measure the mediating and dependent variables, and the mediator is assumed to causally affect the dependent variable. However, participants are not randomly assigned to levels of the mediating variable(s), i.e., the relationship between the mediating and dependent variables is correlational. Although researchers likely know that correlational studies pose a risk of confounding, this problem seems forgotten when thinking about experimental designs randomly assigning participants to levels of the independent variable and measuring the mediator (i.e., "measurement-of-mediation" designs). Experimentally manipulating the mediator provides an approach to solving these problems, yet these methods contain their own set of challenges (e.g., Bullock, Green, & Ha, 2010). We describe types of experimental manipulations targeting the mediator (manipulations demonstrating a causal effect of the mediator on the dependent variable and manipulations targeting the strength of the causal effect of the mediator) and types of experimental designs (double randomization, concurrent double randomization, and parallel), provide published examples of the designs, and discuss the strengths and challenges of each design. Therefore, the goals of this paper include providing a practical guide to manipulation-of-mediator designs in light of their challenges and encouraging researchers to use more rigorous approaches to mediation because manipulation-of-mediator designs strengthen the ability to infer causality of the mediating variable on the dependent variable.

  11. Strong influence of variable treatment on the performance of numerically defined ecological regions.

    PubMed

    Snelder, Ton; Lehmann, Anthony; Lamouroux, Nicolas; Leathwick, John; Allenbach, Karin

    2009-10-01

    Numerical clustering has frequently been used to define hierarchically organized ecological regionalizations, but there has been little robust evaluation of their performance (i.e., the degree to which regions discriminate areas with similar ecological character). In this study we investigated the effect of the weighting and treatment of input variables on the performance of regionalizations defined by agglomerative clustering across a range of hierarchical levels. For this purpose, we developed three ecological regionalizations of Switzerland of increasing complexity using agglomerative clustering. Environmental data for our analysis were drawn from a 400 m grid and consisted of estimates of 11 environmental variables for each grid cell describing climate, topography and lithology. Regionalization 1 was defined from the environmental variables which were given equal weights. We used the same variables in Regionalization 2 but weighted and transformed them on the basis of a dissimilarity model that was fitted to land cover composition data derived for a random sample of cells from interpretation of aerial photographs. Regionalization 3 was a further two-stage development of Regionalization 2 where specific classifications, also weighted and transformed using dissimilarity models, were applied to 25 small scale "sub-domains" defined by Regionalization 2. Performance was assessed in terms of the discrimination of land cover composition for an independent set of sites using classification strength (CS), which measured the similarity of land cover composition within classes and the dissimilarity between classes. Regionalization 2 performed significantly better than Regionalization 1, but the largest gains in performance, compared to Regionalization 1, occurred at coarse hierarchical levels (i.e., CS did not increase significantly beyond the 25-region level). Regionalization 3 performed better than Regionalization 2 beyond the 25-region level and CS values continued to increase to the 95-region level. The results show that the performance of regionalizations defined by agglomerative clustering are sensitive to variable weighting and transformation. We conclude that large gains in performance can be achieved by training classifications using dissimilarity models. However, these gains are restricted to a narrow range of hierarchical levels because agglomerative clustering is unable to represent the variation in importance of variables at different spatial scales. We suggest that further advances in the numerical definition of hierarchically organized ecological regionalizations will be possible with techniques developed in the field of statistical modeling of the distribution of community composition.

  12. Experimental toxicology: Issues of statistics, experimental design, and replication.

    PubMed

    Briner, Wayne; Kirwan, Jeral

    2017-01-01

    The difficulty of replicating experiments has drawn considerable attention. Issues with replication occur for a variety of reasons ranging from experimental design to laboratory errors to inappropriate statistical analysis. Here we review a variety of guidelines for statistical analysis, design, and execution of experiments in toxicology. In general, replication can be improved by using hypothesis driven experiments with adequate sample sizes, randomization, and blind data collection techniques. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. The effect of asset-based wealth inequality on problem drinking among rural Thai elders: a prospective population-based cohort study.

    PubMed

    Jirapramukpitak, Tawanchai; Abas, Melanie; Tangchonlatip, Kanchana; Punpuing, Sureeporn

    2014-01-01

    Evidence on the link between income inequality and alcohol-related problems is scarce, inconclusive and dominated by studies from the developed world. The use of income as a proxy measure for wealth is also questionable, particularly in developing countries. The goal of the present study is to explore the contextual influence of asset-based wealth inequality on problem drinking among Thai older adults. A population-based cohort study with a one-year follow-up was nested in a Demographic Surveillance System (DSS) of 100 villages in western Thailand. Data were drawn from a random sample of 1104 older residents, aged 60 or over (one per household) drawn from all 100 villages, of whom 982 (89%) provided problem drinking data at follow-up. The primary outcome measure was a validated Thai version of the Alcohol-Used Disorder Identification Test for problem drinking. Living in areas of high wealth inequality was prospectively associated with a greater risk for problem drinking among older people (adjusted odds ratio 2.30, 95% confidence intervals 1.02-5.22), after adjusting for individual-level and village-level factors. A rise in wealth inequality over the year was also independently associated with an increased risk of problem drinking (adjusted odds ratio 2.89, 95% confidence intervals 1.24-6.65). The associations were not explained by the social capital, status anxiety or psychosocial stress variables. The data suggest that wealth inequality and an increase in inequality across time lead to a greater risk of problem drinking. Efforts should be directed towards reducing gaps and preventing large jumps in inequality in the communities. Further research should investigate the effect of asset-based inequality on various health risk behaviors and its specific mediating pathways. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. An investigation of the effect of an essential oil mouthrinse on induced bacteraemia: a pilot study.

    PubMed

    Fine, Daniel H; Furgang, David; McKiernan, Marie; Tereski-Bischio, Debra; Ricci-Nittel, Danette; Zhang, Paul; Araujo, Marcelo W B

    2010-09-01

    This pilot study was designed to assess the effect of an essential oil antiseptic mouthrinse (EOM) in reducing bloodstream bacteria after chewing an apple. From a panel of 200, we screened 62 individuals with mild-to-moderate gingivitis. Twenty-two individuals who showed a bacteraemia after chewing an apple were enrolled. Subjects were recalled, instructed to chew an apple, had blood drawn (first baseline), and were randomly assigned EOM or a control (C) treatment for 2 weeks. Subjects were recalled, given an apple, and had blood taken for bacterial counts. Following a 1-week fluoride dentifrice wash-out, subjects were recalled, given the apple challenge, had blood drawn (second baseline), assigned the alternate treatment, and recalled for testing. Differences between baseline and 2-week post-treatment (EOM versus C) in blood-borne bacteria were assessed by analysis of covariance. Mean aerobic blood-borne bacteria decreased by 68.5% (17.7 viable counts from baseline; p<0.001), while anaerobic counts decreased by 70.7% (14.5 mean viable counts from baseline; p<0.001) for the EOM treatment. No reduction was seen for the C treatment. This double-blind, placebo-controlled, randomized, 2-week cross-over study showed that rinsing with essential oils reduced the level of bloodstream bacteria in subjects with mild-to-moderate gingivitis.

  15. Dietary exposure to aflatoxin in human male infertility in Benin City, Nigeria.

    PubMed

    Ibeh, I N; Uraih, N; Ogonar, J I

    1994-01-01

    To discover the relationship between aflatoxin levels, if any, in serum of infertile men in comparison with random controls from the community. In a parallel experiment, adult male rats were given an aflatoxin-contaminated diet. 100 adult males, yielding 50 semen samples, from men attending Infertility Clinics at a university teaching hospital and 50 normal men in the same community. The staple foods of the men were assayed for aflatoxin content. The rats were given the aflatoxin-rich diet, and their spermatozoa were examined and their ability to reproduce assessed. A random sampling of semen from 100 adult males comprising 50 samples drawn from infertile men and 50 drawn from normal individuals within the same community revealed the presence of aflatoxins in 20 semen samples from the infertile group (40.0%) and four samples from the fertile group (8.0%). The mean aflatoxin concentrations were 1.660 +/- 0.04 micrograms/mL (infertile men) and 1.041 +/- 0.01 micrograms/mL (fertile men). Infertile men with aflatoxin in their semen showed a higher percentage of spermatozoal abnormality (50.0%) than the fertile men (10.0-15.0%). Dietary exposure of adult male Albino rats to aflatoxin (8.5 micrograms AF1/g of Guinea growers feed for 14 days) produced deleterious effects on the spermatozoa of the affected rats, producing features that resemble those seen in semen of infertile men exposed to aflatoxin.

  16. Compliance-Effect Correlation Bias in Instrumental Variables Estimators

    ERIC Educational Resources Information Center

    Reardon, Sean F.

    2010-01-01

    Instrumental variable estimators hold the promise of enabling researchers to estimate the effects of educational treatments that are not (or cannot be) randomly assigned but that may be affected by randomly assigned interventions. Examples of the use of instrumental variables in such cases are increasingly common in educational and social science…

  17. Statistical properties of solar flares and coronal mass ejections through the solar cycle

    NASA Astrophysics Data System (ADS)

    Telloni, Daniele; Carbone, Vincenzo; Lepreti, Fabio; Antonucci, Ester

    2016-03-01

    Waiting Time Distributions (WTDs) of solar flares are investigated all through the solar cycle. The same approach applied to Coronal Mass Ejections (CMEs) in a previous work is considered here for flare occurrence. Our analysis reveals that flares and CMEs share some common statistical properties, which result dependent on the level of solar activity. Both flares and CMEs seem to independently occur during minimum solar activity phases, whilst their WTDs significantly deviate from a Poisson function at solar maximum, thus suggesting that these events are correlated. The characteristics of WTDs are constrained by the physical processes generating those eruptions associated with flares and CMEs. A scenario may be drawn in which different mechanisms are actively at work during different phases of the solar cycle. Stochastic processes, most likely related to random magnetic reconnections of the field lines, seem to play a key role during solar minimum periods. On the other hand, persistent processes, like sympathetic eruptions associated to the variability of the photospheric magnetism, are suggested to dominate during periods of high solar activity. Moreover, despite the similar statistical properties shown by flares and CMEs, as it was mentioned above, their WTDs appear different in some aspects. During solar minimum periods, the flare occurrence randomness seems to be more evident than for CMEs. Those persistent mechanisms generating interdependent events during maximum periods of solar activity can be suggested to play a more important role for CMEs than for flares, thus mitigating the competitive action of the random processes, which seem instead strong enough to weaken the correlations among flare event occurrence during solar minimum periods. However, it cannot be excluded that the physical processes at the basis of the origin of the temporal correlation between solar events are different for flares and CMEs, or that, more likely, more sophisticated effects are at work at the same time leading to an even more complex picture. This work represents a first step for further investigations.

  18. On the Misconception of Multicollinearity in Detection of Moderating Effects: Multicollinearity Is Not Always Detrimental.

    PubMed

    Shieh, Gwowen

    2010-05-28

    Due to its extensive applicability and computational ease, moderated multiple regression (MMR) has been widely employed to analyze interaction effects between 2 continuous predictor variables. Accordingly, considerable attention has been drawn toward the supposed multicollinearity problem between predictor variables and their cross-product term. This article attempts to clarify the misconception of multicollinearity in MMR studies. The counterintuitive yet beneficial effects of multicollinearity on the ability to detect moderator relationships are explored. Comprehensive treatments and numerical investigations are presented for the simplest interaction model and more complex three-predictor setting. The results provide critical insight that both helps avoid misleading interpretations and yields better understanding for the impact of intercorrelation among predictor variables in MMR analyses.

  19. Lungworm Infections in German Dairy Cattle Herds — Seroprevalence and GIS-Supported Risk Factor Analysis

    PubMed Central

    Schunn, Anne-Marie; Conraths, Franz J.; Staubach, Christoph; Fröhlich, Andreas; Forbes, Andrew; Strube, Christina

    2013-01-01

    In November 2008, a total of 19,910 bulk tank milk (BTM) samples were obtained from dairy farms from all over Germany, corresponding to about 20% of all German dairy herds, and analysed for antibodies against the bovine lungworm Dictyocaulus viviparus by use of the recombinant MSP-ELISA. A total number of 3,397 (17.1%; n = 19,910) BTM samples tested seropositive. The prevalences in individual German federal states varied between 0.0% and 31.2% positive herds. A geospatial map was drawn to show the distribution of seropositive and seronegative herds per postal code area. ELISA results were further analysed for associations with land-use and climate data. Bivariate statistical analysis was used to identify potential spatial risk factors for dictyocaulosis. Statistically significant positive associations were found between lungworm seropositive herds and the proportion of water bodies and grassed area per postal code area. Variables that showed a statistically significant association with a positive BTM test were included in a logistic regression model, which was further refined by controlled stepwise selection of variables. The low Pseudo R2 values (0.08 for the full model and 0.06 for the final model) and further evaluation of the model by ROC analysis indicate that additional, unrecorded factors (e.g. management factors) or random effects may substantially contribute to lungworm infections in dairy cows. Veterinarians should include lungworms in the differential diagnosis of respiratory disease in dairy cattle, particularly those at pasture. Monitoring of herds through BTM screening for antibodies can help farmers and veterinarians plan and implement appropriate control measures. PMID:24040243

  20. Childhood Risk Factors for Early-Onset Drinking*

    PubMed Central

    Donovan, John E.; Molina, Brooke S. G.

    2011-01-01

    Objective: There is relatively little research on the childhood antecedent predictors of early-onset alcohol use. This study examined an array of psychosocial variables assessed at age 10 and reflecting Problem Behavior Theory as potential antecedent risk factors for the initiation of alcohol use at age 14 or younger. Method: A sample of 452 children (238 girls) ages 8 or 10 and their families was drawn from Allegheny County, PA, using targeted-age directory sampling and random-digit dialing procedures. Children and parents were interviewed using computer-assisted interviews. Logistic regression analyses were used to examine the age-10 univariate and multivariate predictors of the initiation of alcohol use by age 14 or younger. Results: Twenty-five percent of the sample reported having more than a sip or a taste of alcohol in their life by age 14. Sex, race, and age cohort did not relate to early drinking status. Children with two parents were less likely to initiate drinking early. Early initiation of drinking related significantly to an array of antecedent risk factors (personality, social environment, and behavioral) assessed at age 10 that reflect psychosocial proneness for problem behavior. In the multivariate model, the variables most predictive of early-onset drinking were having a single parent, sipping or tasting alcohol by age 10, having parents who also started drinking at an early age, and parental drinking frequency. Conclusions: Initiation of alcohol use by age 14 reflects childhood psychosocial proneness to engage in problem behavior as measured by Problem Behavior Theory and having a family environment conducive to alcohol use. PMID:21906502

  1. Distinct Correlation Structure Supporting a Rate-Code for Sound Localization in the Owl’s Auditory Forebrain

    PubMed Central

    2017-01-01

    Abstract While a topographic map of auditory space exists in the vertebrate midbrain, it is absent in the forebrain. Yet, both brain regions are implicated in sound localization. The heterogeneous spatial tuning of adjacent sites in the forebrain compared to the midbrain reflects different underlying circuitries, which is expected to affect the correlation structure, i.e., signal (similarity of tuning) and noise (trial-by-trial variability) correlations. Recent studies have drawn attention to the impact of response correlations on the information readout from a neural population. We thus analyzed the correlation structure in midbrain and forebrain regions of the barn owl’s auditory system. Tetrodes were used to record in the midbrain and two forebrain regions, Field L and the downstream auditory arcopallium (AAr), in anesthetized owls. Nearby neurons in the midbrain showed high signal and noise correlations (RNCs), consistent with shared inputs. As previously reported, Field L was arranged in random clusters of similarly tuned neurons. Interestingly, AAr neurons displayed homogeneous monotonic azimuth tuning, while response variability of nearby neurons was significantly less correlated than the midbrain. Using a decoding approach, we demonstrate that low RNC in AAr restricts the potentially detrimental effect it can have on information, assuming a rate code proposed for mammalian sound localization. This study harnesses the power of correlation structure analysis to investigate the coding of auditory space. Our findings demonstrate distinct correlation structures in the auditory midbrain and forebrain, which would be beneficial for a rate-code framework for sound localization in the nontopographic forebrain representation of auditory space. PMID:28674698

  2. Longitudinal study of effects of patient characteristics on direct costs in Alzheimer disease.

    PubMed

    Zhu, C W; Scarmeas, N; Torgan, R; Albert, M; Brandt, J; Blacker, D; Sano, M; Stern, Y

    2006-09-26

    To estimate long-term trajectories of direct cost of caring for patients with Alzheimer disease (AD) and examine the effects of patients' characteristics on cost longitudinally. The sample is drawn from the Predictors Study, a large, multicenter cohort of patients with probable AD, prospectively followed up annually for up to 7 years in three university-based AD centers in the United States. Random effects models estimated the effects of patients' clinical and sociodemographic characteristics on direct cost of care. Direct cost included cost associated with medical and nonmedical care. Clinical characteristics included cognitive status (measured by Mini-Mental State Examination), functional capacity (measured by Blessed Dementia Rating Scale [BDRS]), psychotic symptoms, behavioral problems, depressive symptoms, extrapyramidal signs, and comorbidities. The model also controlled for patients' sex, age, and living arrangements. Total direct cost increased from approximately 9,239 dollars per patient per year at baseline, when all patients were at the early stages of the disease, to 19,925 dollars by year 4. After controlling for other variables, a one-point increase in the BDRS score increased total direct cost by 7.7%. One more comorbid condition increased total direct cost by 14.3%. Total direct cost was 20.8% lower for patients living at home compared with those living in an institutional setting. Total direct cost of caring for patients with Alzheimer disease increased substantially over time. Much of the cost increases were explained by patients' clinical and demographic variables. Comorbidities and functional capacity were associated with higher direct cost over time.

  3. Foundations for computer simulation of a low pressure oil flooded single screw air compressor

    NASA Astrophysics Data System (ADS)

    Bein, T. W.

    1981-12-01

    The necessary logic to construct a computer model to predict the performance of an oil flooded, single screw air compressor is developed. The geometric variables and relationships used to describe the general single screw mechanism are developed. The governing equations to describe the processes are developed from their primary relationships. The assumptions used in the development are also defined and justified. The computer model predicts the internal pressure, temperature, and flowrates through the leakage paths throughout the compression cycle of the single screw compressor. The model uses empirical external values as the basis for the internal predictions. The computer values are compared to the empirical values, and conclusions are drawn based on the results. Recommendations are made for future efforts to improve the computer model and to verify some of the conclusions that are drawn.

  4. Reliability Coupled Sensitivity Based Design Approach for Gravity Retaining Walls

    NASA Astrophysics Data System (ADS)

    Guha Ray, A.; Baidya, D. K.

    2012-09-01

    Sensitivity analysis involving different random variables and different potential failure modes of a gravity retaining wall focuses on the fact that high sensitivity of a particular variable on a particular mode of failure does not necessarily imply a remarkable contribution to the overall failure probability. The present paper aims at identifying a probabilistic risk factor ( R f ) for each random variable based on the combined effects of failure probability ( P f ) of each mode of failure of a gravity retaining wall and sensitivity of each of the random variables on these failure modes. P f is calculated by Monte Carlo simulation and sensitivity analysis of each random variable is carried out by F-test analysis. The structure, redesigned by modifying the original random variables with the risk factors, is safe against all the variations of random variables. It is observed that R f for friction angle of backfill soil ( φ 1 ) increases and cohesion of foundation soil ( c 2 ) decreases with an increase of variation of φ 1 , while R f for unit weights ( γ 1 and γ 2 ) for both soil and friction angle of foundation soil ( φ 2 ) remains almost constant for variation of soil properties. The results compared well with some of the existing deterministic and probabilistic methods and found to be cost-effective. It is seen that if variation of φ 1 remains within 5 %, significant reduction in cross-sectional area can be achieved. But if the variation is more than 7-8 %, the structure needs to be modified. Finally design guidelines for different wall dimensions, based on the present approach, are proposed.

  5. Anderson localization for radial tree-like random quantum graphs

    NASA Astrophysics Data System (ADS)

    Hislop, Peter D.; Post, Olaf

    We prove that certain random models associated with radial, tree-like, rooted quantum graphs exhibit Anderson localization at all energies. The two main examples are the random length model (RLM) and the random Kirchhoff model (RKM). In the RLM, the lengths of each generation of edges form a family of independent, identically distributed random variables (iid). For the RKM, the iid random variables are associated with each generation of vertices and moderate the current flow through the vertex. We consider extensions to various families of decorated graphs and prove stability of localization with respect to decoration. In particular, we prove Anderson localization for the random necklace model.

  6. Comfortable synchronization of cyclic drawing movements with a metronome.

    PubMed

    Repp, Bruno H

    2011-02-01

    Continuous circle drawing is considered a paragon of emergent timing, whereas the timing of finger tapping is said to be event-based. Synchronization with a metronome, however, must to some extent be event-based for both types of movement. Because the target events in the movement trajectory are more poorly defined in circle drawing than in tapping, circle drawing shows more variable asynchronies with a metronome than does tapping. One factor that may have contributed to high variability in past studies is that circle size, drawing direction, and target point were prescribed and perhaps outside the comfort range. In the present study, participants were free to choose most comfortable settings of these parameters for two continuously drawn shapes, circles and infinity signs, while synchronizing with a regular or intermittently perturbed metronome at four different tempi. Results showed that preferred circle sizes were generally smaller than in previous studies but tended to increase as tempo decreased. Synchronization results were similar for circles and infinity signs, and similar to earlier results for circles drawn within a fixed template (Repp & Steinman, 2010). Comparison with tapping data still showed drawing to exhibit much greater variability and persistence of asynchronies as well as slower phase correction in response to phase shifts in the metronome. With comfort level ruled out as a factor, these differences can now be attributed more confidently to differences in event definition and/or movement dynamics. Copyright © 2010 Elsevier B.V. All rights reserved.

  7. Unbiased split variable selection for random survival forests using maximally selected rank statistics.

    PubMed

    Wright, Marvin N; Dankowski, Theresa; Ziegler, Andreas

    2017-04-15

    The most popular approach for analyzing survival data is the Cox regression model. The Cox model may, however, be misspecified, and its proportionality assumption may not always be fulfilled. An alternative approach for survival prediction is random forests for survival outcomes. The standard split criterion for random survival forests is the log-rank test statistic, which favors splitting variables with many possible split points. Conditional inference forests avoid this split variable selection bias. However, linear rank statistics are utilized by default in conditional inference forests to select the optimal splitting variable, which cannot detect non-linear effects in the independent variables. An alternative is to use maximally selected rank statistics for the split point selection. As in conditional inference forests, splitting variables are compared on the p-value scale. However, instead of the conditional Monte-Carlo approach used in conditional inference forests, p-value approximations are employed. We describe several p-value approximations and the implementation of the proposed random forest approach. A simulation study demonstrates that unbiased split variable selection is possible. However, there is a trade-off between unbiased split variable selection and runtime. In benchmark studies of prediction performance on simulated and real datasets, the new method performs better than random survival forests if informative dichotomous variables are combined with uninformative variables with more categories and better than conditional inference forests if non-linear covariate effects are included. In a runtime comparison, the method proves to be computationally faster than both alternatives, if a simple p-value approximation is used. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  8. Coverage of Developed and Developing Nations in American Wire Services to Asia.

    ERIC Educational Resources Information Center

    Giffard, C. Anthony

    A study was conducted to contrast the news coverage of developed and developing nations, and of the United States specifically, as transmitted to Asia by the Associated Press (AP) and United Press International (UPI). A total of 556 AP reports and 453 UPI reports drawn from a 6-week period were coded for more than 100 variables and 47 topics. The…

  9. The evolution of mapping habitat for northern spotted owls (Strix occidentalis caurina): A comparison of photo-interpreted, Landsat-based, and lidar-based habitat maps

    Treesearch

    Steven H. Ackers; Raymond J. Davis; Keith A. Olsen; Katie M. Dugger

    2015-01-01

    Wildlife habitat mapping has evolved at a rapid pace over the last fewdecades. Beginning with simple, often subjective, hand-drawn maps, habitat mapping now involves complex species distribution models (SDMs) using mapped predictor variables derived from remotely sensed data. For species that inhabit large geographic areas, remote sensing technology is often...

  10. Enhancing Creativity by Using NLN (Neurological-Linguistic Programming) and Guided Imagery

    ERIC Educational Resources Information Center

    Rosemarin, Shoshana

    2016-01-01

    The significance of the role of creativity as an essential component of giftedness has long been assumed by most of the experts in the field. The most fertile creations will often be those formed of elements drawn from domains which are far apart. It is assumed that creativity is a personality variable, and not an ability, and thus it is believed…

  11. Simulation of multivariate stationary stochastic processes using dimension-reduction representation methods

    NASA Astrophysics Data System (ADS)

    Liu, Zhangjun; Liu, Zenghui; Peng, Yongbo

    2018-03-01

    In view of the Fourier-Stieltjes integral formula of multivariate stationary stochastic processes, a unified formulation accommodating spectral representation method (SRM) and proper orthogonal decomposition (POD) is deduced. By introducing random functions as constraints correlating the orthogonal random variables involved in the unified formulation, the dimension-reduction spectral representation method (DR-SRM) and the dimension-reduction proper orthogonal decomposition (DR-POD) are addressed. The proposed schemes are capable of representing the multivariate stationary stochastic process with a few elementary random variables, bypassing the challenges of high-dimensional random variables inherent in the conventional Monte Carlo methods. In order to accelerate the numerical simulation, the technique of Fast Fourier Transform (FFT) is integrated with the proposed schemes. For illustrative purposes, the simulation of horizontal wind velocity field along the deck of a large-span bridge is proceeded using the proposed methods containing 2 and 3 elementary random variables. Numerical simulation reveals the usefulness of the dimension-reduction representation methods.

  12. Generating Variable and Random Schedules of Reinforcement Using Microsoft Excel Macros

    ERIC Educational Resources Information Center

    Bancroft, Stacie L.; Bourret, Jason C.

    2008-01-01

    Variable reinforcement schedules are used to arrange the availability of reinforcement following varying response ratios or intervals of time. Random reinforcement schedules are subtypes of variable reinforcement schedules that can be used to arrange the availability of reinforcement at a constant probability across number of responses or time.…

  13. Optimization Of Mean-Semivariance-Skewness Portfolio Selection Model In Fuzzy Random Environment

    NASA Astrophysics Data System (ADS)

    Chatterjee, Amitava; Bhattacharyya, Rupak; Mukherjee, Supratim; Kar, Samarjit

    2010-10-01

    The purpose of the paper is to construct a mean-semivariance-skewness portfolio selection model in fuzzy random environment. The objective is to maximize the skewness with predefined maximum risk tolerance and minimum expected return. Here the security returns in the objectives and constraints are assumed to be fuzzy random variables in nature and then the vagueness of the fuzzy random variables in the objectives and constraints are transformed into fuzzy variables which are similar to trapezoidal numbers. The newly formed fuzzy model is then converted into a deterministic optimization model. The feasibility and effectiveness of the proposed method is verified by numerical example extracted from Bombay Stock Exchange (BSE). The exact parameters of fuzzy membership function and probability density function are obtained through fuzzy random simulating the past dates.

  14. Random Variables: Simulations and Surprising Connections.

    ERIC Educational Resources Information Center

    Quinn, Robert J.; Tomlinson, Stephen

    1999-01-01

    Features activities for advanced second-year algebra students in grades 11 and 12. Introduces three random variables and considers an empirical and theoretical probability for each. Uses coins, regular dice, decahedral dice, and calculators. (ASK)

  15. Binomial leap methods for simulating stochastic chemical kinetics.

    PubMed

    Tian, Tianhai; Burrage, Kevin

    2004-12-01

    This paper discusses efficient simulation methods for stochastic chemical kinetics. Based on the tau-leap and midpoint tau-leap methods of Gillespie [D. T. Gillespie, J. Chem. Phys. 115, 1716 (2001)], binomial random variables are used in these leap methods rather than Poisson random variables. The motivation for this approach is to improve the efficiency of the Poisson leap methods by using larger stepsizes. Unlike Poisson random variables whose range of sample values is from zero to infinity, binomial random variables have a finite range of sample values. This probabilistic property has been used to restrict possible reaction numbers and to avoid negative molecular numbers in stochastic simulations when larger stepsize is used. In this approach a binomial random variable is defined for a single reaction channel in order to keep the reaction number of this channel below the numbers of molecules that undergo this reaction channel. A sampling technique is also designed for the total reaction number of a reactant species that undergoes two or more reaction channels. Samples for the total reaction number are not greater than the molecular number of this species. In addition, probability properties of the binomial random variables provide stepsize conditions for restricting reaction numbers in a chosen time interval. These stepsize conditions are important properties of robust leap control strategies. Numerical results indicate that the proposed binomial leap methods can be applied to a wide range of chemical reaction systems with very good accuracy and significant improvement on efficiency over existing approaches. (c) 2004 American Institute of Physics.

  16. Do bioclimate variables improve performance of climate envelope models?

    USGS Publications Warehouse

    Watling, James I.; Romañach, Stephanie S.; Bucklin, David N.; Speroterra, Carolina; Brandt, Laura A.; Pearlstine, Leonard G.; Mazzotti, Frank J.

    2012-01-01

    Climate envelope models are widely used to forecast potential effects of climate change on species distributions. A key issue in climate envelope modeling is the selection of predictor variables that most directly influence species. To determine whether model performance and spatial predictions were related to the selection of predictor variables, we compared models using bioclimate variables with models constructed from monthly climate data for twelve terrestrial vertebrate species in the southeastern USA using two different algorithms (random forests or generalized linear models), and two model selection techniques (using uncorrelated predictors or a subset of user-defined biologically relevant predictor variables). There were no differences in performance between models created with bioclimate or monthly variables, but one metric of model performance was significantly greater using the random forest algorithm compared with generalized linear models. Spatial predictions between maps using bioclimate and monthly variables were very consistent using the random forest algorithm with uncorrelated predictors, whereas we observed greater variability in predictions using generalized linear models.

  17. Investigating Factorial Invariance of Latent Variables Across Populations When Manifest Variables Are Missing Completely

    PubMed Central

    Widaman, Keith F.; Grimm, Kevin J.; Early, Dawnté R.; Robins, Richard W.; Conger, Rand D.

    2013-01-01

    Difficulties arise in multiple-group evaluations of factorial invariance if particular manifest variables are missing completely in certain groups. Ad hoc analytic alternatives can be used in such situations (e.g., deleting manifest variables), but some common approaches, such as multiple imputation, are not viable. At least 3 solutions to this problem are viable: analyzing differing sets of variables across groups, using pattern mixture approaches, and a new method using random number generation. The latter solution, proposed in this article, is to generate pseudo-random normal deviates for all observations for manifest variables that are missing completely in a given sample and then to specify multiple-group models in a way that respects the random nature of these values. An empirical example is presented in detail comparing the 3 approaches. The proposed solution can enable quantitative comparisons at the latent variable level between groups using programs that require the same number of manifest variables in each group. PMID:24019738

  18. A Procedure to Detect Item Bias Present Simultaneously in Several Items

    DTIC Science & Technology

    1991-04-25

    exhibit a coherent and major biasing influence at the test level. In partic- ular, this can be true even if each individual item displays only a minor...response functions (IRFs) without the use of item parameter estimation algorithms when the sample size is too small for their use. Thissen, Steinberg...convention). A random sample of examinees is drawn from each group, and a test of N items is administered to them. Typically it is suspected that a

  19. Explaining Zipf's law via a mental lexicon

    NASA Astrophysics Data System (ADS)

    Allahverdyan, Armen E.; Deng, Weibing; Wang, Q. A.

    2013-12-01

    Zipf's law is the major regularity of statistical linguistics that has served as a prototype for rank-frequency relations and scaling laws in natural sciences. Here we show that Zipf's law—together with its applicability for a single text and its generalizations to high and low frequencies including hapax legomena—can be derived from assuming that the words are drawn into the text with random probabilities. Their a priori density relates, via the Bayesian statistics, to the mental lexicon of the author who produced the text.

  20. A unified approach for squeal instability analysis of disc brakes with two types of random-fuzzy uncertainties

    NASA Astrophysics Data System (ADS)

    Lü, Hui; Shangguan, Wen-Bin; Yu, Dejie

    2017-09-01

    Automotive brake systems are always subjected to various types of uncertainties and two types of random-fuzzy uncertainties may exist in the brakes. In this paper, a unified approach is proposed for squeal instability analysis of disc brakes with two types of random-fuzzy uncertainties. In the proposed approach, two uncertainty analysis models with mixed variables are introduced to model the random-fuzzy uncertainties. The first one is the random and fuzzy model, in which random variables and fuzzy variables exist simultaneously and independently. The second one is the fuzzy random model, in which uncertain parameters are all treated as random variables while their distribution parameters are expressed as fuzzy numbers. Firstly, the fuzziness is discretized by using α-cut technique and the two uncertainty analysis models are simplified into random-interval models. Afterwards, by temporarily neglecting interval uncertainties, the random-interval models are degraded into random models, in which the expectations, variances, reliability indexes and reliability probabilities of system stability functions are calculated. And then, by reconsidering the interval uncertainties, the bounds of the expectations, variances, reliability indexes and reliability probabilities are computed based on Taylor series expansion. Finally, by recomposing the analysis results at each α-cut level, the fuzzy reliability indexes and probabilities can be obtained, by which the brake squeal instability can be evaluated. The proposed approach gives a general framework to deal with both types of random-fuzzy uncertainties that may exist in the brakes and its effectiveness is demonstrated by numerical examples. It will be a valuable supplement to the systematic study of brake squeal considering uncertainty.

  1. Size differences in migrant sandpiper flocks: ghosts in ephemeral guilds

    USGS Publications Warehouse

    Eldridge, J.L.; Johnson, D.H.

    1988-01-01

    Scolopacid sandpipers were studied from 1980 until 1984 during spring migration in North Dakota. Common species foraging together in mixed-species flocks differed in bill length most often by 20 to 30 percent (ratios from 1.2:1 to 1.3:1). Observed flocks were compared to computer generated flocks drawn from three source pools of Arctic-nesting sandpipers. The source pools included 51 migrant species from a global pool, 33 migrant species from a Western Hemisphere pool, and 13 species that migrated through North Dakota. The observed flocks formed randomly from the available species that used the North Dakota migration corridor but the North Dakota species were not a random selection from the Western Hemisphere and global pools of Arctic-nesting scolopacid sandpipers. In short, the ephemeral, mixed-species foraging flocks that we observed in North Dakota were random mixes from a non-random pool. The size-ratio distributions were consistent with the interpretation that use of this migration corridor by sandpipers has been influenced by some form of size-related selection such as competition.

  2. Knowledge about writing influences reading: Dynamic visual information about letter production facilitates letter identification.

    PubMed

    Schubert, Teresa; Reilhac, Caroline; McCloskey, Michael

    2018-06-01

    How are reading and writing related? In this study, we address the relationship between letter identification and letter production, uncovering a link in which production information can be used to identify letters presented dynamically. By testing an individual with a deficit in letter identification, we identified a benefit which would be masked by ceiling effects in unimpaired readers. In Experiment 1 we found that letter stimuli defined by the direction of dot motion (tiny dots within letter move leftward, background dots move rightward) provided no advantage over static letters. In Experiment 2, we tested dynamic stimuli in which the letter shapes emerged over time: drawn as they would be written, drawn in reverse, or with the letter shape filled in randomly. Improved identification was observed only for letters drawn as they are typically written. These results demonstrate that information about letter production can be integrated into letter identification, and point to bi-directional connections between stored letter production information (used for writing) and abstract letter identity representations (used in both reading and writing). The links from stored production information to abstract letter identities allow the former to activate the latter. We also consider the implications of our results for remediation of acquired letter identification deficits, including letter-drawing treatments and the underlying cause of their efficacy. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Selection of Variables in Cluster Analysis: An Empirical Comparison of Eight Procedures

    ERIC Educational Resources Information Center

    Steinley, Douglas; Brusco, Michael J.

    2008-01-01

    Eight different variable selection techniques for model-based and non-model-based clustering are evaluated across a wide range of cluster structures. It is shown that several methods have difficulties when non-informative variables (i.e., random noise) are included in the model. Furthermore, the distribution of the random noise greatly impacts the…

  4. Personal and psychosocial predictors of doping use in physical activity settings: a meta-analysis.

    PubMed

    Ntoumanis, Nikos; Ng, Johan Y Y; Barkoukis, Vassilis; Backhouse, Susan

    2014-11-01

    There is a growing body of empirical evidence on demographic and psychosocial predictors of doping intentions and behaviors utilizing a variety of variables and conceptual models. However, to date there has been no attempt to quantitatively synthesize the available evidence and identify the strongest predictors of doping. Using meta-analysis, we aimed to (i) determine effect sizes of psychological (e.g. attitudes) and social-contextual factors (e.g. social norms), and demographic (e.g. sex and age) variables on doping intentions and use; (ii) examine variables that moderate such effect sizes; and (iii) test a path analysis model, using the meta-analyzed effect sizes, based on variables from the theory of planned behavior (TPB). Articles were identified from online databases, by contacting experts in the field, and searching the World Anti-Doping Agency website. Studies that measured doping behaviors and/or doping intentions, and at least one other demographic, psychological, or social-contextual variable were included. We identified 63 independent datasets. Study information was extracted by using predefined data fields and taking into account study quality indicators. A random effects meta-analysis was carried out, correcting for sampling and measurement error, and identifying moderator variables. Path analysis was conducted on a subset of studies that utilized the TPB. Use of legal supplements, perceived social norms, and positive attitudes towards doping were the strongest positive correlates of doping intentions and behaviors. In contrast, morality and self-efficacy to refrain from doping had the strongest negative association with doping intentions and behaviors. Furthermore, path analysis suggested that attitudes, perceived norms, and self-efficacy to refrain from doping predicted intentions to dope and, indirectly, doping behaviors. Various meta-analyzed effect sizes were based on a small number of studies, which were correlational in nature. This is a limitation of the extant literature. This review identifies a number of important correlates of doping intention and behavior, many of which were measured via self-reports and were drawn from an extended TPB framework. Future research might benefit from embracing other conceptual models of doping behavior and adopting experimental methodologies that will test some of the identified correlates in an effort to develop targeted anti-doping policies and programs.

  5. Predictive models of energy consumption in multi-family housing in College Station, Texas

    NASA Astrophysics Data System (ADS)

    Ali, Hikmat Hummad

    Patterns of energy consumption in apartment buildings are different than those in single-family houses. Apartment buildings have different physical characteristics, and their inhabitants have different demographic attributes. This study develops models that predict energy usage in apartment buildings in College Station. This is accomplished by analyzing and identifying the predictive variables that affect energy usage, studying the consumption patterns, and creating formulas based on combinations of these variables. According to the hypotheses and the specific research context, a cross-sectional design strategy is adopted. This choice implies analyses across variations within a sample of fourplex apartments in College Station. The data available for analysis include the monthly billing data along with the physical characteristics of the building, climate data for College Station, and occupant demographic characteristics. A simple random sampling procedure is adopted. The sample size of 176 apartments is drawn from the population in such a way that every possible sample has the same chance of being selected. Statistical methods used to interpret the data include univariate analysis (mean, standard deviation, range, and distribution of data), correlation analysis, regression analysis, and ANOVA (analyses of variance). The results show there are significant differences in cooling efficiency and actual energy consumption among different building types, but there are no significant differences in heating consumption. There are no significant differences in actual energy consumption between student and non-student groups or among ethnic groups. The findings indicate that there are significant differences in actual energy consumption among marital status groups and educational level groups. The multiple regression procedures show there is a significant relationship between normalized annual consumption and the combined variables of floor area, marital status, dead band, construction material, summer thermostat setting, heating, slope, and base load, as well as a relationship between cooling slope and the combined variables of share wall, floor level, summer thermostat setting, external wall, and American household. In addition, there is a significant relationship between heating slope and the combined variables of winter thermostat setting, market value, student, and rent. The results also indicate there is a relationship between base load and the combined variables of floor area, market value, age of the building, marital status, student, and summer thermostat setting.

  6. Effects of Three Motivationally Targeted Mobile Device Applications on Initial Physical Activity and Sedentary Behavior Change in Midlife and Older Adults: A Randomized Trial.

    PubMed

    King, Abby C; Hekler, Eric B; Grieco, Lauren A; Winter, Sandra J; Sheats, Jylana L; Buman, Matthew P; Banerjee, Banny; Robinson, Thomas N; Cirimele, Jesse

    2016-01-01

    While there has been an explosion of mobile device applications (apps) promoting healthful behaviors, including physical activity and sedentary patterns, surprisingly few have been based explicitly on strategies drawn from behavioral theory and evidence. This study provided an initial 8-week evaluation of three different customized physical activity-sedentary behavior apps drawn from conceptually distinct motivational frames in comparison with a commercially available control app. Ninety-five underactive adults ages 45 years and older with no prior smartphone experience were randomized to use an analytically framed app, a socially framed app, an affectively framed app, or a diet-tracker control app. Daily physical activity and sedentary behavior were measured using the smartphone's built-in accelerometer and daily self-report measures. Mixed-effects models indicated that, over the 8-week period, the social app users showed significantly greater overall increases in weekly accelerometry-derived moderate to vigorous physical activity relative to the other three arms (P values for between-arm differences = .04-.005; Social vs. Control app: d = 1.05, CI = 0.44,1.67; Social vs. Affect app: d = 0.89, CI = 0.27,1.51; Social vs. Analytic app: d = 0.89, CI = 0.27,1.51), while more variable responses were observed among users of the other two motivationally framed apps. Social app users also had significantly lower overall amounts of accelerometry-derived sedentary behavior relative to the other three arms (P values for between-arm differences = .02-.001; Social vs. Control app: d = 1.10,CI = 0.48,1.72; Social vs. Affect app: d = 0.94, CI = 0.32,1.56; Social vs. Analytic app: d = 1.24, CI = 0.59,1.89). Additionally, Social and Affect app users reported lower overall sitting time compared to the other two arms (P values for between-arm differences < .001; Social vs. Control app: d = 1.59,CI = 0.92, 2.25; Social vs. Analytic app: d = 1.89,CI = 1.17, 2.61; Affect vs. Control app: d = 1.19,CI = 0.56, 1.81; Affect vs. Analytic app: d = 1.41,CI = 0.74, 2.07). The results provide initial support for the use of a smartphone-delivered social frame in the early induction of both physical activity and sedentary behavior changes. The information obtained also sets the stage for further investigation of subgroups that might particularly benefit from different motivationally framed apps in these two key health promotion areas. ClinicalTrials.gov NCT01516411.

  7. Sampling-Based Stochastic Sensitivity Analysis Using Score Functions for RBDO Problems with Correlated Random Variables

    DTIC Science & Technology

    2010-08-01

    a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. a ...SECURITY CLASSIFICATION OF: This study presents a methodology for computing stochastic sensitivities with respect to the design variables, which are the...Random Variables Report Title ABSTRACT This study presents a methodology for computing stochastic sensitivities with respect to the design variables

  8. Reward and uncertainty in exploration programs

    NASA Technical Reports Server (NTRS)

    Kaufman, G. M.; Bradley, P. G.

    1971-01-01

    A set of variables which are crucial to the economic outcome of petroleum exploration are discussed. These are treated as random variables; the values they assume indicate the number of successes that occur in a drilling program and determine, for a particular discovery, the unit production cost and net economic return if that reservoir is developed. In specifying the joint probability law for those variables, extreme and probably unrealistic assumptions are made. In particular, the different random variables are assumed to be independently distributed. Using postulated probability functions and specified parameters, values are generated for selected random variables, such as reservoir size. From this set of values the economic magnitudes of interest, net return and unit production cost are computed. This constitutes a single trial, and the procedure is repeated many times. The resulting histograms approximate the probability density functions of the variables which describe the economic outcomes of an exploratory drilling program.

  9. A single-loop optimization method for reliability analysis with second order uncertainty

    NASA Astrophysics Data System (ADS)

    Xie, Shaojun; Pan, Baisong; Du, Xiaoping

    2015-08-01

    Reliability analysis may involve random variables and interval variables. In addition, some of the random variables may have interval distribution parameters owing to limited information. This kind of uncertainty is called second order uncertainty. This article develops an efficient reliability method for problems involving the three aforementioned types of uncertain input variables. The analysis produces the maximum and minimum reliability and is computationally demanding because two loops are needed: a reliability analysis loop with respect to random variables and an interval analysis loop for extreme responses with respect to interval variables. The first order reliability method and nonlinear optimization are used for the two loops, respectively. For computational efficiency, the two loops are combined into a single loop by treating the Karush-Kuhn-Tucker (KKT) optimal conditions of the interval analysis as constraints. Three examples are presented to demonstrate the proposed method.

  10. Characteristics associated with purchasing antidepressant or antianxiety medications through primary care in Israel.

    PubMed

    Ayalon, Liat; Gross, Revital; Yaari, Aviv; Feldhamer, Elan; Balicer, Ran; Goldfracht, Margalit

    2011-09-01

    This study analyzed the role of patient and physician characteristics associated with the purchase of antidepressant or antianxiety medications in Israel, a country that has a universal health care system. A national sample of 30,000 primary care patients over the age of 22 was randomly drawn from the registry of the largest health care fund in Israel. Data concerning medication purchase between January and December 2006 were extracted. Physician and patient characteristics were merged with Israel's unique identification number. Multilevel analysis was conducted to identify patient- and physician-level predictors of medication purchase. Overall, 19% (N = 4,762) of the sample purchased antidepressant or antianxiety medications. Individuals with greater general medical and psychiatric comorbidity were more likely to purchase antidepressant or antianxiety medications. Older adults, women, those of higher socioeconomic status, and immigrants (with the exception of Jews born in Asia or Africa) were also more likely to purchase medications. Arabs and Jews born in Asia and Africa were less likely to purchase medications even after all other variables were accounted for. Physician characteristics were minimally associated with the purchase of medications. The findings demonstrate that despite universal health care access, there were variations by population groups. Educational efforts should target patients as well as physicians.

  11. The cultural influences on help-seeking among a national sample of victimized Latino women.

    PubMed

    Sabina, Chiara; Cuevas, Carlos A; Schally, Jennifer L

    2012-06-01

    The current study examined the influence of legal status and cultural variables (i.e., acculturation, gender role ideology and religious coping) on the formal and informal help-seeking efforts of Latino women who experienced interpersonal victimization. The sample was drawn from the Sexual Assault Among Latinas (SALAS) Study that surveyed 2,000 self-identified adult Latino women. The random digit dial methodology employed in high-density Latino neighborhoods resulted in a cooperation rate of 53.7%. Women who experienced lifetime victimization (n = 714) reported help-seeking efforts in response to their most distressful victimization event that occurred in the US. Approximately one-third of the women reported formal help-seeking and about 70% of women reported informal help-seeking. Help-seeking responses were generally not predicted by the cultural factors measured, with some exceptions. Anglo orientation and negative religious coping increased the likelihood of formal help-seeking. Positive religious coping, masculine gender role and Anglo acculturation increased the likelihood of specific forms of informal help-seeking. Latino orientation decreased the likelihood of talking to a sibling. Overall, these findings reinforce the importance of bilingual culturally competent services as cultural factors shape the ways in which women respond to victimization either formally or within their social networks.

  12. Virtual Active Touch Using Randomly Patterned Intracortical Microstimulation

    PubMed Central

    O’Doherty, Joseph E.; Lebedev, Mikhail A.; Li, Zheng; Nicolelis, Miguel A.L.

    2012-01-01

    Intracortical microstimulation (ICMS) has promise as a means for delivering somatosensory feedback in neuroprosthetic systems. Various tactile sensations could be encoded by temporal, spatial, or spatiotemporal patterns of ICMS. However, the applicability of temporal patterns of ICMS to artificial tactile sensation during active exploration is unknown, as is the minimum discriminable difference between temporally modulated ICMS patterns. We trained rhesus monkeys in an active exploration task in which they discriminated periodic pulse-trains of ICMS (200 Hz bursts at a 10 Hz secondary frequency) from pulse trains with the same average pulse rate, but distorted periodicity (200 Hz bursts at a variable instantaneous secondary frequency). The statistics of the aperiodic pulse trains were drawn from a gamma distribution with mean inter-burst intervals equal to those of the periodic pulse trains. The monkeys distinguished periodic pulse trains from aperiodic pulse trains with coefficients of variation 0.25 or greater. Reconstruction of movement kinematics, extracted from the activity of neuronal populations recorded in the sensorimotor cortex concurrent with the delivery of ICMS feedback, improved when the recording intervals affected by ICMS artifacts were removed from analysis. These results add to the growing evidence that temporally patterned ICMS can be used to simulate a tactile sense for neuroprosthetic devices. PMID:22207642

  13. Pisa syndrome in Parkinson's disease: An integrated approach from pathophysiology to management.

    PubMed

    Tinazzi, Michele; Geroin, Christian; Gandolfi, Marialuisa; Smania, Nicola; Tamburin, Stefano; Morgante, Francesca; Fasano, Alfonso

    2016-12-01

    Pisa syndrome was first described in 1972 in patients treated with neuroleptics. Since 2003, when it was first reported in patients with Parkinson's disease (PD), Pisa syndrome has progressively drawn the attention of clinicians and researchers. Although emerging evidence has partially clarified its prevalence and pathophysiology, the current debate revolves around diagnostic criteria and assessment and the effectiveness of pharmacological, surgical, and rehabilitative approaches. Contrary to initial thought, Pisa syndrome is common among PD patients, with an estimated prevalence of 8.8% according to a large survey. Furthermore, it is associated with the following specific patient features: more severe motor phenotype, ongoing combined pharmacological treatment with levodopa and dopamine agonists, gait disorders, and such comorbidities as osteoporosis and arthrosis. The present literature on treatment outcomes is scant, and the uneven effectiveness of specific treatments has produced conflicting results. This might be because of the limited knowledge of Pisa syndrome pathophysiology and its variable clinical presentation, which further complicates designing randomized clinical trials on this condition. However, because some forms of Pisa syndrome are potentially reversible, there is growing consensus on the importance of its early recognition and the importance of pharmacological adjustment and rehabilitation. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

  14. [Psychosocial problems in the elderly in Rotterdam and point of departure for prevention].

    PubMed

    Kocken, P L; Klaus-Meijs, W M

    1993-08-01

    The aim of this study is to examine the prevalence of psycho-social problems among the elderly in order to plan prevention-programs. A questionnaire was sent in 1990 to a sample of 1989 inhabitants of the city of Rotterdam aged 65-79 years living on their own, drawn at random from the municipal registrar's office (response 58%). The results show that one third of the respondents experiences psycho-social problems. Groups at risk are: women, men who live alone, those with a low socio-economic status, people who live on their own but receive limited support from institutions. These socio-demographic variables explain only 5% of the variance in psycho-social well-being. Risk-indicators for psycho-social problems are problems in the performance of activities of daily living (ADL) and household-activities (HHA) as well as decreased social support. The relationship between satisfaction with living environment and psycho-social problems is affected by these risk-indicators. Elderly experiencing only psycho-social problems and those experiencing only ADL/HHA-problems visited their general practitioner during the last three months just frequently. Elderly experiencing both psycho-social and ADL/HHA-problems most frequently visited their GP. More elderly in Rotterdam compared to elderly in some other Dutch cities and to normscores seem to have psycho-social problems.

  15. ICD-11 complex PTSD among Israeli male perpetrators of intimate partner violence: Construct validity and risk factors.

    PubMed

    Gilbar, Ohad; Hyland, Philip; Cloitre, Marylene; Dekel, Rachel

    2018-03-01

    The International Classification of Diseases 11th Version (ICD-11) will include Complex Posttraumatic Stress Disorder (CPTSD) as a unique diagnostic entity comprising core PTSD and DSO (disturbances in self-organization) symptoms. The current study had three aims: (1) assessing the validity of CPTSD in a unique population of male perpetrators of intimate partner violence; (2) examining whether exposure to different types of traumatic events would be associated with the two proposed CPTSD factors, namely PTSD or DSO; and (3) assessing the differential association of various sociodemographic and symptom characteristics with each factor. Participants were 234 males drawn randomly from a sample of 2600 men receiving treatment at 66 domestic violence centers in Israel. Data were collected using the International Trauma Questionnaire (ITQ) - Hebrew version. Confirmatory factor analysis supported the factorial validity of ICD-11 CPTSD. Cumulative lifetime trauma and physical childhood neglect were associated with PTSD and DSO, while cumulative childhood violence exposure was associated only with DSO. Anxiety was associated only with DSO; depression more strongly with DSO than PTSD. Religious level contributed only to PTSD; compulsory military service only to DSO. The study supports the distinction between PTSD and DSO in the CPTSD construct and introduces the role of cultural variables. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Academic buoyancy and academic outcomes: towards a further understanding of students with attention-deficit/hyperactivity disorder (ADHD), students without ADHD, and academic buoyancy itself.

    PubMed

    Martin, Andrew J

    2014-03-01

    Academic buoyancy is students' capacity to successfully overcome setback and challenge that is typical of the ordinary course of everyday academic life. It may represent an important factor on the psycho-educational landscape assisting students who experience difficulties in school and schoolwork. This study investigated the role of academic buoyancy in the achievement and cognitive, affective and behavioural engagement of (1) students with attention-deficit/hyperactivity disorder (ADHD) and (2) 'regular' (or 'general') students residing in the same classrooms and schools. The study also sought to extend prior research into academic buoyancy by including previously neglected and potentially influential factors such as personality and socio-economic status. Participants were n = 87 high school students with ADHD, n = 3374 non-ADHD peers, and n = 87 randomly drawn non-ADHD students. Survey-based data were analysed using multigroup (ADHD, non-ADHD, randomly weighted non-ADHD) multivariate (multiple independent/covariate and dependent variables) path analysis. The findings revealed a significant and positive association between academic buoyancy and outcomes for students with ADHD that generalized to non-ADHD groups. On occasion where academic buoyancy effects differed between the groups, effects favoured students with ADHD. Furthermore, academic buoyancy explained significant variance in outcomes for both groups of students after covariates (age, gender, parent education, language background, socio-economic status, personality) were entered. It is concluded that there is merit in widely promoting and fostering academic buoyancy among ADHD and non-ADHD students alike - and that academic buoyancy explains variance in outcomes beyond major intrapersonal factors such as personality, socio-economic status, ethnicity, and the like. © 2012 The British Psychological Society.

  17. Investigating expectation effects using multiple physiological measures

    PubMed Central

    Siller, Alexander; Ambach, Wolfgang; Vaitl, Dieter

    2015-01-01

    The study aimed at experimentally investigating whether the human body can anticipate future events under improved methodological conditions. Previous studies have reported contradictory results for the phenomenon typically called presentiment. If the positive findings are accurate, they call into doubt our views about human perception, and if they are inaccurate, a plausible conventional explanation might be based on the experimental design of the previous studies, in which expectation due to item sequences was misinterpreted as presentiment. To address these points, we opted to collect several physiological variables, to test different randomization types and to manipulate subjective significance individually. For the latter, we combined a mock crime scenario, in which participants had to steal specific items, with a concealed information test (CIT), in which the participants had to conceal their knowledge when interrogated about items they had stolen or not stolen. We measured electrodermal activity, respiration, finger pulse, heart rate (HR), and reaction times. The participants (n = 154) were assigned randomly to four different groups. Items presented in the CIT were either drawn with replacement (full) or without replacement (pseudo) and were either presented category-wise (cat) or regardless of categories (nocat). To understand how these item sequences influence expectation and modulate physiological reactions, we compared the groups with respect to effect sizes for stolen vs. not stolen items. Group pseudo_cat yielded the highest effect sizes, and pseudo_nocat yielded the lowest. We could not find any evidence of presentiment but did find evidence of physiological correlates of expectation. Due to the design differing fundamentally from previous studies, these findings do not allow for conclusions on the question whether the expectation bias is being confounded with presentiment. PMID:26500600

  18. New insights on antimicrobial efficacy of copper surfaces in the healthcare environment: a systematic review.

    PubMed

    Chyderiotis, S; Legeay, C; Verjat-Trannoy, D; Le Gallou, F; Astagneau, P; Lepelletier, D

    2018-03-29

    Hospital-acquired infections (HAIs) are a major public health issue. The potential of antimicrobial copper surfaces in reducing HAIs' rates is of interest but remains unclear. We conducted a systematic review of studies assessing the activity of copper surfaces (colony-forming unit (CFU)/surface, both in vitro and in situ) as well as clinical studies. In vitro study protocols were analysed through a tailored checklist developed specifically for this review, in situ studies and non-randomized clinical studies were assessed using the ORION (Outbreak Reports and Intervention studies Of Nosocomial infection) checklist and randomized clinical studies using the CONSORT guidelines. The search was conducted using PubMed database with the keywords 'copper' and 'surfaces' and 'healthcare associated infections' or 'antimicrobial'. References from relevant articles, including reviews, were assessed and added when appropriate. Articles were added until 30 August 2016. Overall, 20 articles were selected for review including 10 in vitro, eight in situ and two clinical studies. Copper surfaces were found to have variable antimicrobial activity both in vitro and in situ, although the heterogeneity in the designs and the reporting of the results prevented conclusions from being drawn regarding their spectrum and activity/time compared to controls. Copper effect on HAIs incidence remains unclear because of the limited published data and the lack of robust designs. Most studies have potential conflicts of interest with copper industries. Copper surfaces have demonstrated an antimicrobial activity but the implications of this activity in healthcare settings are still unclear. No clear effect on healthcare associated infections has been demonstrated yet. Copyright © 2018 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  19. Workshop on Incomplete Network Data Held at Sandia National Labs – Livermore

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

    Soundarajan, Sucheta; Wendt, Jeremy D.

    2016-06-01

    While network analysis is applied in a broad variety of scientific fields (including physics, computer science, biology, and the social sciences), how networks are constructed and the resulting bias and incompleteness have drawn more limited attention. For example, in biology, gene networks are typically developed via experiment -- many actual interactions are likely yet to be discovered. In addition to this incompleteness, the data-collection processes can introduce significant bias into the observed network datasets. For instance, if you observe part of the World Wide Web network through a classic random walk, then high degree nodes are more likely to bemore » found than if you had selected nodes at random. Unfortunately, such incomplete and biasing data collection methods must be often used.« less

  20. Is dyslexia necessarily associated with negative feelings of self-worth? A review and implications for future research.

    PubMed

    Burden, Robert

    2008-08-01

    This paper will provide an overview of research in the past 20 years into the relationship between dyslexia and various aspects of self-perception, including self-concept, self-esteem, self-efficacy and locus of control. Problems are identified relating to the measurement of some of the most widely used constructs, as is the need for more precise identification of key variables relating to them. Critical issues concerning the assumptions that can be drawn from largely correlational data are highlighted also. The conclusion is drawn that an alternative approach to research in this area is required to enhance our understanding of how those suffering from learning disabilities of a dyslexic nature develop a positive or negative sense of identity. Suggestions are made as to how this can be achieved by drawing upon attribution theory and other aspects of social psychology. Copyright 2008 John Wiley & Sons, Ltd.

  1. The childhood and family dynamics of transvestites.

    PubMed

    Schott, R L

    1995-06-01

    This article reports a survey of childhood experiences and family dynamics reported by a sample of 85 cross-dressing males drawn from the readership of a magazine for transvestites. The sample had a higher percentage of only children and eldest children compared to a national sample and also a much closer relationship with their mothers than with their fathers. Their identification as nuclear or marginal transvestites or transsexuals is related to the quality of the reported relationship with the mother, to the factors they identify as associated with their cross-dressing, and to their sexual orientation. Covert cross-dressers account for over three fourths of the subjects, but those who were overt (their cross-dressing openly encouraged by female family members) show significantly different patterns and distributions on several variables. A constellation of family and parental relationships is proposed--drawn in part from the insights of object relations and family systems theory--which may contribute to the development of transvestism.

  2. Learning Latent Variable and Predictive Models of Dynamical Systems

    DTIC Science & Technology

    2009-10-01

    stable over the full 1000 frame image sequence without significant damping. C. Sam- ples drawn from a least squares synthesized sequences (top), and...LDS stabilizing algorithms, LB-1 and LB-2. Bars at every 20 timesteps denote variance in the results. CG provides the best stable short term predictions...observations. This thesis contributes (1) novel learning algorithms for existing dynamical system models that overcome significant limitations of previous

  3. On the Use of Sibiling Data to Estimate the Effects of Family Background, Cognitive Skills, and Schooling: Results from the Kalamazoo Brothers Study. Discussion Papers 374-76.

    ERIC Educational Resources Information Center

    Olneck, Michael R.

    Sibling data drawn from the Kalamazoo Brothers sample are used in this report to assess the adequacy of conventional sociological variables for measuring family background, to estimate the overall effects of family background on test scores, education, occupational status, and earning, and to control family background when estimating the effects…

  4. Context-invariant quasi hidden variable (qHV) modelling of all joint von Neumann measurements for an arbitrary Hilbert space

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

    Loubenets, Elena R.

    We prove the existence for each Hilbert space of the two new quasi hidden variable (qHV) models, statistically noncontextual and context-invariant, reproducing all the von Neumann joint probabilities via non-negative values of real-valued measures and all the quantum product expectations—via the qHV (classical-like) average of the product of the corresponding random variables. In a context-invariant model, a quantum observable X can be represented by a variety of random variables satisfying the functional condition required in quantum foundations but each of these random variables equivalently models X under all joint von Neumann measurements, regardless of their contexts. The proved existence ofmore » this model negates the general opinion that, in terms of random variables, the Hilbert space description of all the joint von Neumann measurements for dimH≥3 can be reproduced only contextually. The existence of a statistically noncontextual qHV model, in particular, implies that every N-partite quantum state admits a local quasi hidden variable model introduced in Loubenets [J. Math. Phys. 53, 022201 (2012)]. The new results of the present paper point also to the generality of the quasi-classical probability model proposed in Loubenets [J. Phys. A: Math. Theor. 45, 185306 (2012)].« less

  5. Type 2 diabetes and cardiac autonomic neuropathy screening using dynamic pupillometry

    PubMed Central

    Lerner, Alana G.; Bernabé-Ortiz, Antonio; Ticse, Ray; Hernandez, Arturo; Huaylinos, Yvonne; Pinto, Miguel E.; Málaga, Germán; Checkley, William; Gilman, Robert H.; Miranda, J. Jaime

    2015-01-01

    Aim To determine if changes in pupillary response are useful as a screening tool for diabetes and to assess whether pupillometry is associated with cardiac autonomic neuropathy. Methods We conducted a cross-sectional study with participants drawn from two settings: a hospital and a community site. At the community site, individuals with newly diagnosed diabetes as well as a random sample of control individuals without diabetes, confirmed by oral glucose tolerance test, were selected. Participants underwent an LED light stimulus test and eight pupillometry variables were measured. Outcomes were diabetes, defined by oral glucose tolerance test, and cardiac autonomic dysfunction, determined by a positive readout on two of four diagnostic tests: heart rate response to the Valsalva manoeuvre; orthostatic hypotension; 30:15 ratio; and expiration-to-inspiration ratio. The area under the curve, best threshold, sensitivity and specificity of each pupillometry variable was calculated. Results Data from 384 people, 213 with diabetes, were analysed. The mean (±SD) age of the people with diabetes was 58.6 (±8.2) years and in the control subjects it was 56.1 (±8.6) years. When comparing individuals with and without diabetes, the amplitude of the pupil reaction had the highest area under the curve [0.69 (sensitivity: 78%; specificity: 55%)]. Cardiac autonomic neuropathy was present in 51 of the 138 people evaluated (37.0%; 95% CI 28.8–45.1). To diagnose cardiac autonomic neuropathy, two pupillometry variables had the highest area under the curve: baseline pupil radius [area under the curve: 0.71 (sensitivity: 51%; specificity: 84%)], and amplitude of the pupil reaction [area under the curve: 070 (sensitivity: 82%; specificity: 55%)]. Conclusions Pupillometry is an inexpensive technique to screen for diabetes and cardiac autonomic neuropathy, but it does not have sufficient accuracy for clinical use as a screening tool. PMID:25761508

  6. Type 2 diabetes and cardiac autonomic neuropathy screening using dynamic pupillometry.

    PubMed

    Lerner, A G; Bernabé-Ortiz, A; Ticse, R; Hernandez, A; Huaylinos, Y; Pinto, M E; Málaga, G; Checkley, W; Gilman, R H; Miranda, J J

    2015-11-01

    To determine if changes in pupillary response are useful as a screening tool for diabetes and to assess whether pupillometry is associated with cardiac autonomic neuropathy. We conducted a cross-sectional study with participants drawn from two settings: a hospital and a community site. At the community site, individuals with newly diagnosed diabetes as well as a random sample of control individuals without diabetes, confirmed by oral glucose tolerance test, were selected. Participants underwent an LED light stimulus test and eight pupillometry variables were measured. Outcomes were diabetes, defined by oral glucose tolerance test, and cardiac autonomic dysfunction, determined by a positive readout on two of four diagnostic tests: heart rate response to the Valsalva manoeuvre; orthostatic hypotension; 30:15 ratio; and expiration-to-inspiration ratio. The area under the curve, best threshold, sensitivity and specificity of each pupillometry variable was calculated. Data from 384 people, 213 with diabetes, were analysed. The mean (±sd) age of the people with diabetes was 58.6 (±8.2) years and in the control subjects it was 56.1 (±8.6) years. When comparing individuals with and without diabetes, the amplitude of the pupil reaction had the highest area under the curve [0.69 (sensitivity: 78%; specificity: 55%)]. Cardiac autonomic neuropathy was present in 51 of the 138 people evaluated (37.0%; 95% CI 28.8-45.1). To diagnose cardiac autonomic neuropathy, two pupillometry variables had the highest area under the curve: baseline pupil radius [area under the curve: 0.71 (sensitivity: 51%; specificity: 84%)], and amplitude of the pupil reaction [area under the curve: 0.70 (sensitivity: 82%; specificity: 55%)]. Pupillometry is an inexpensive technique to screen for diabetes and cardiac autonomic neuropathy, but it does not have sufficient accuracy for clinical use as a screening tool. © 2015 The Authors. Diabetic Medicine © 2015 Diabetes UK.

  7. Uncertainty Quantification of Hypothesis Testing for the Integrated Knowledge Engine

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

    Cuellar, Leticia

    2012-05-31

    The Integrated Knowledge Engine (IKE) is a tool of Bayesian analysis, based on Bayesian Belief Networks or Bayesian networks for short. A Bayesian network is a graphical model (directed acyclic graph) that allows representing the probabilistic structure of many variables assuming a localized type of dependency called the Markov property. The Markov property in this instance makes any node or random variable to be independent of any non-descendant node given information about its parent. A direct consequence of this property is that it is relatively easy to incorporate new evidence and derive the appropriate consequences, which in general is notmore » an easy or feasible task. Typically we use Bayesian networks as predictive models for a small subset of the variables, either the leave nodes or the root nodes. In IKE, since most applications deal with diagnostics, we are interested in predicting the likelihood of the root nodes given new observations on any of the children nodes. The root nodes represent the various possible outcomes of the analysis, and an important problem is to determine when we have gathered enough evidence to lean toward one of these particular outcomes. This document presents criteria to decide when the evidence gathered is sufficient to draw a particular conclusion or decide in favor of a particular outcome by quantifying the uncertainty in the conclusions that are drawn from the data. The material in this document is organized as follows: Section 2 presents briefly a forensics Bayesian network, and we explore evaluating the information provided by new evidence by looking first at the posterior distribution of the nodes of interest, and then at the corresponding posterior odds ratios. Section 3 presents a third alternative: Bayes Factors. In section 4 we finalize by showing the relation between the posterior odds ratios and Bayes factors and showing examples these cases, and in section 5 we conclude by providing clear guidelines of how to use these for the type of Bayesian networks used in IKE.« less

  8. Properties of behavior under different random ratio and random interval schedules: A parametric study.

    PubMed

    Dembo, M; De Penfold, J B; Ruiz, R; Casalta, H

    1985-03-01

    Four pigeons were trained to peck a key under different values of a temporally defined independent variable (T) and different probabilities of reinforcement (p). Parameter T is a fixed repeating time cycle and p the probability of reinforcement for the first response of each cycle T. Two dependent variables were used: mean response rate and mean postreinforcement pause. For all values of p a critical value for the independent variable T was found (T=1 sec) in which marked changes took place in response rate and postreinforcement pauses. Behavior typical of random ratio schedules was obtained at T 1 sec and behavior typical of random interval schedules at T 1 sec. Copyright © 1985. Published by Elsevier B.V.

  9. DEFINED CONTRIBUTION PLANS, DEFINED BENEFIT PLANS, AND THE ACCUMULATION OF RETIREMENT WEALTH

    PubMed Central

    Poterba, James; Rauh, Joshua; Venti, Steven; Wise, David

    2010-01-01

    The private pension structure in the United States, once dominated by defined benefit (DB) plans, is currently divided between defined contribution (DC) and DB plans. Wealth accumulation in DC plans depends on the participant's contribution behavior and on financial market returns, while accumulation in DB plans is sensitive to a participant's labor market experience and to plan parameters. This paper simulates the distribution of retirement wealth under representative DB and DC plans. It uses data from the Health and Retirement Study (HRS) to explore how asset returns, earnings histories, and retirement plan characteristics contribute to the variation in retirement wealth outcomes. We simulate DC plan accumulation by randomly assigning individuals a share of wages that they and their employer contribute to the plan. We consider several possible asset allocation strategies, with asset returns drawn from the historical return distribution. Our DB plan simulations draw earnings histories from the HRS, and randomly assign each individual a pension plan drawn from a sample of large private and public defined benefit plans. The simulations yield distributions of both DC and DB wealth at retirement. Average retirement wealth accruals under current DC plans exceed average accruals under private sector DB plans, although DC plans are also more likely to generate very low retirement wealth outcomes. The comparison of current DC plans with more generous public sector DB plans is less definitive, because public sector DB plans are more generous on average than their private sector counterparts. PMID:21057597

  10. [Self-concept of school-age children: the norm in Kaohsiung].

    PubMed

    Chin, C C; Liu, Y Y; Ka, J K

    1989-05-01

    This study has two objectives: (1) to establish the norm of three graphical projective tests (Children's Social-Self Test, Children's Attitude Inventory and Children's Self-Concept Inventory), and (2) to explore the influence of sex, order of birth, social economic status of family, and leadership of class that effect self-concept of the school-age children. These subjects are selected from elementary schools in Kaohsiung, twenty-two classes are drawn out from each grade by systemic-random sampling. Then two classes are drawn out from 22 classes at random to arrange retest for reliability. The total subjects are 6207 students. From October 1987 to June 1988, six researchers are divided into three group to conduct the test. Besides establishing the norm, we find results from analysis of data as follow: 1. The reliability and validity of three graphical projective tests are good, they can be used for assessing the self-concept of school-age children. 2. The grade, sex, order of birth, social economic status of family, leadership of class all influence the self-concept of school-age children. 3. The self-concept and the grade has negative correlation. 4. The self-concept and the social economic status of family has positive correlation. 5. The girls have higher self-concept than the boys. 6. The order of first-born or second-born has higher self-concept than the others. 7. The ones who are leaders of class have higher self-concept than the others.

  11. The Expected Sample Variance of Uncorrelated Random Variables with a Common Mean and Some Applications in Unbalanced Random Effects Models

    ERIC Educational Resources Information Center

    Vardeman, Stephen B.; Wendelberger, Joanne R.

    2005-01-01

    There is a little-known but very simple generalization of the standard result that for uncorrelated random variables with common mean [mu] and variance [sigma][superscript 2], the expected value of the sample variance is [sigma][superscript 2]. The generalization justifies the use of the usual standard error of the sample mean in possibly…

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

  13. Peer Influence, Genetic Propensity, and Binge Drinking: A Natural Experiment and a Replication.

    PubMed

    Guo, Guang; Li, Yi; Wang, Hongyu; Cai, Tianji; Duncan, Greg J

    2015-11-01

    The authors draw data from the College Roommate Study (ROOM) and the National Longitudinal Study of Adolescent Health to investigate gene-environment interaction effects on youth binge drinking. In ROOM, the environmental influence was measured by the precollege drinking behavior of randomly assigned roommates. Random assignment safeguards against friend selection and removes the threat of gene-environment correlation that makes gene-environment interaction effects difficult to interpret. On average, being randomly assigned a drinking peer as opposed to a nondrinking peer increased college binge drinking by 0.5-1.0 episodes per month, or 20%-40% the average amount of binge drinking. However, this peer influence was found only among youths with a medium level of genetic propensity for alcohol use; those with either a low or high genetic propensity were not influenced by peer drinking. A replication of the findings is provided in data drawn from Add Health. The study shows that gene-environment interaction analysis can uncover social-contextual effects likely to be missed by traditional sociological approaches.

  14. Do little interactions get lost in dark random forests?

    PubMed

    Wright, Marvin N; Ziegler, Andreas; König, Inke R

    2016-03-31

    Random forests have often been claimed to uncover interaction effects. However, if and how interaction effects can be differentiated from marginal effects remains unclear. In extensive simulation studies, we investigate whether random forest variable importance measures capture or detect gene-gene interactions. With capturing interactions, we define the ability to identify a variable that acts through an interaction with another one, while detection is the ability to identify an interaction effect as such. Of the single importance measures, the Gini importance captured interaction effects in most of the simulated scenarios, however, they were masked by marginal effects in other variables. With the permutation importance, the proportion of captured interactions was lower in all cases. Pairwise importance measures performed about equal, with a slight advantage for the joint variable importance method. However, the overall fraction of detected interactions was low. In almost all scenarios the detection fraction in a model with only marginal effects was larger than in a model with an interaction effect only. Random forests are generally capable of capturing gene-gene interactions, but current variable importance measures are unable to detect them as interactions. In most of the cases, interactions are masked by marginal effects and interactions cannot be differentiated from marginal effects. Consequently, caution is warranted when claiming that random forests uncover interactions.

  15. The influence of an uncertain force environment on reshaping trial-to-trial motor variability.

    PubMed

    Izawa, Jun; Yoshioka, Toshinori; Osu, Rieko

    2014-09-10

    Motor memory is updated to generate ideal movements in a novel environment. When the environment changes every trial randomly, how does the brain incorporate this uncertainty into motor memory? To investigate how the brain adapts to an uncertain environment, we considered a reach adaptation protocol where individuals practiced moving in a force field where a noise was injected. After they had adapted, we measured the trial-to-trial variability in the temporal profiles of the produced hand force. We found that the motor variability was significantly magnified by the adaptation to the random force field. Temporal profiles of the motor variance were significantly dissociable between two different types of random force fields experienced. A model-based analysis suggests that the variability is generated by noise in the gains of the internal model. It further suggests that the trial-to-trial motor variability magnified by the adaptation in a random force field is generated by the uncertainty of the internal model formed in the brain as a result of the adaptation.

  16. A person based formula for allocating commissioning funds to general practices in England: development of a statistical model

    PubMed Central

    Smith, Peter; Gravelle, Hugh; Martin, Steve; Bardsley, Martin; Rice, Nigel; Georghiou, Theo; Dusheiko, Mark; Billings, John; Lorenzo, Michael De; Sanderson, Colin

    2011-01-01

    Objectives To develop a formula for allocating resources for commissioning hospital care to all general practices in England based on the health needs of the people registered in each practice Design Multivariate prospective statistical models were developed in which routinely collected electronic information from 2005-6 and 2006-7 on individuals and the areas in which they lived was used to predict their costs of hospital care in the next year, 2007-8. Data on individuals included all diagnoses recorded at any inpatient admission. Models were developed on a random sample of 5 million people and validated on a second random sample of 5 million people and a third sample of 5 million people drawn from a random sample of practices. Setting All general practices in England as of 1 April 2007. All NHS inpatient admissions and outpatient attendances for individuals registered with a general practice on that date. Subjects All individuals registered with a general practice in England at 1 April 2007. Main outcome measures Power of the statistical models to predict the costs of the individual patient or each practice’s registered population for 2007-8 tested with a range of metrics (R2 reported here). Comparisons of predicted costs in 2007-8 with actual costs incurred in the same year were calculated by individual and by practice. Results Models including person level information (age, sex, and ICD-10 codes diagnostic recorded) and a range of area level information (such as socioeconomic deprivation and supply of health facilities) were most predictive of costs. After accounting for person level variables, area level variables added little explanatory power. The best models for resource allocation could predict upwards of 77% of the variation in costs at practice level, and about 12% at the person level. With these models, the predicted costs of about a third of practices would exceed or undershoot the actual costs by 10% or more. Smaller practices were more likely to be in these groups. Conclusions A model was developed that performed well by international standards, and could be used for allocations to practices for commissioning. The best formulas, however, could predict only about 12% of the variation in next year’s costs of most inpatient and outpatient NHS care for each individual. Person-based diagnostic data significantly added to the predictive power of the models. PMID:22110252

  17. Comonotonic bounds on the survival probabilities in the Lee-Carter model for mortality projection

    NASA Astrophysics Data System (ADS)

    Denuit, Michel; Dhaene, Jan

    2007-06-01

    In the Lee-Carter framework, future survival probabilities are random variables with an intricate distribution function. In large homogeneous portfolios of life annuities, value-at-risk or conditional tail expectation of the total yearly payout of the company are approximately equal to the corresponding quantities involving random survival probabilities. This paper aims to derive some bounds in the increasing convex (or stop-loss) sense on these random survival probabilities. These bounds are obtained with the help of comonotonic upper and lower bounds on sums of correlated random variables.

  18. Variance approach for multi-objective linear programming with fuzzy random of objective function coefficients

    NASA Astrophysics Data System (ADS)

    Indarsih, Indrati, Ch. Rini

    2016-02-01

    In this paper, we define variance of the fuzzy random variables through alpha level. We have a theorem that can be used to know that the variance of fuzzy random variables is a fuzzy number. We have a multi-objective linear programming (MOLP) with fuzzy random of objective function coefficients. We will solve the problem by variance approach. The approach transform the MOLP with fuzzy random of objective function coefficients into MOLP with fuzzy of objective function coefficients. By weighted methods, we have linear programming with fuzzy coefficients and we solve by simplex method for fuzzy linear programming.

  19. Trends in anemia management among US hemodialysis patients.

    PubMed

    Coladonato, Joseph A; Frankenfield, Diane L; Reddan, Donal N; Klassen, Preston S; Szczech, Lynda A; Johnson, Curtis A; Owen, William F

    2002-05-01

    This study was undertaken to describe the relationship between hematocrit (Hct) and changes in the prescribed dose of erythropoietin (EPO) as well as selected patient and process care measures across annual national samples of hemodialysis patients from 1994 to 1998. This study uses the cohorts identified in the ESRD Core Indicators Project, random samples of 6181, 6241, 6364, 6634, and 7660 patients, stratified by ESRD Networks drawn for each year from 1994 to 1998. Patient demographic and clinical information was collected from October to December for each year. Surrogates of iron stores and patterns of iron and EPO administration were profiled from 1996 to 1998. Multivariable stepwise linear regression analyses were performed to adjust for potential confounding variables and to identify independent variables associated with Hct and EPO dose. Mean Hct and EPO dose increased each year from 31.1 +/- 5.2% to 34.1 +/- 3.7% and from 58.2 +/- 41.8 U/kg to 68.2 +/- 55.0 U/kg, respectively (P = 0.0001). Increasing Hct was positively associated with male gender, more years on dialysis, older age, higher urea reduction ratio and transferrin saturation, prescription of intravenous iron, and lower ferritin and EPO dose in multivariable models (all P = 0.0001). Male gender, older age, diabetes, higher Hct, and increasing weight, urea reduction ration, and transferrin saturation were associated with lower EPO doses (all P < 0.01). Conversely, intravenous EPO and iron were associated with higher prescribed EPO doses (all P = 0.0001). Although increasing Hct is associated with decreasing EPO dose at the patient level, the increase in Hct seen across years among the cohorts of hemodialysis patients in the United States has been associated with increasing doses of EPO at the population level.

  20. Stature of sub-arctic birch in relation to growth rate, lifespan and tree form.

    PubMed

    Jónsson, Thorbergur Hjalti

    2004-11-01

    Sub-arctic mountain birch Betula pubescens var. pumila communities in the North Atlantic region are of variable stature, ranging from prostrate scrubs to forests with trees up to 12 m high. Four hypotheses were tested, relating growth and population characteristics of sub-arctic birch woodland and scrub to tree stature; i.e. the variable stature of birch woods is due to differences in (1) the mean growth rate; (2) the age-related patterns of growth rate; (3) the life expectancy of stems; or (4) the tree form. A stratified random sample of 300 birch trees was drawn from the total population of indigenous birch woodlands and scrub in Iceland, yielding 286 valid sample genets. The population was divided into three sub-populations with dominant trees 0-2, 2-4 and 4-12 m tall, referred to as birch scrub, birch scrub-woodland and birch forest, respectively. Trees in the scrub population were of more contorted growth form than birch in the scrub-woodland and forest populations. Mean growth rates, mean age and median life expectancies increased significantly with sub-population of greater tree stature. At the population level, annual increment and longevity of birch stems was apparently interrelated as the stems in vigorously growing birch sub-populations had a longer life expectancy than those of slower growth. However, no difference was observed between sub-populations in age-related patterns of extension growth rate. The results were consistent with hypotheses (1), (3) and (4), but hypothesis (2) was rejected. Hence, mountain birch of more vigorous growth attains a greater stature than birch of lesser increment due to faster extension growth rate and a longer lifespan. In addition, the more contorted stem form of scrub populations contributes to their low stature.

  1. Childhood vaccination in rural southwestern Ethiopia: the nexus with demographic factors and women's autonomy.

    PubMed

    Wado, Yohannes Dibaba; Afework, Mesganaw Fantahun; Hindin, Michelle J

    2014-01-01

    Vaccination can reduce child mortality significantly and is a cost effective way to improve child health.Worldwide, more than 22 million children do not receive the basic recommended vaccinations.Vaccination coverage in Ethiopia remains low. Research on child health has focused on socio-economic factors such as maternal education and access to health care, but little attention has been given to demographic factors and women's autonomy within the household. The purpose of this study was to examine the influences of demographic factors and women's autonomy on the completion of childhood vaccination in rural Ethiopia. A cross-sectional community-based study was conducted in a Health and Demographic Survelliance System (HDSS) in southwestern Ethiopia. Data were drawn from a random sample of women with children aged 12-24 months (n = 889). Information on maternal socio-demographic characteristics and household variables were collected using an interviewer-administered structured questionnaire. Vaccination data were obtained from vaccination cards or mother's recall. Multivariate logistic regression was used to assess the association of independent variables with completion of childhood vaccination. Of 889 children aged 12-24 months, 690 (78%) had received at least one vaccination. Only 37% (95% CI, 33.5-39.9) were fully vaccinated. Women's decision making autonomy, number of under-five children in the household, mother's education, use of antenatal care services and proximity to health facility were the main factors associated with full vaccination status. Completion of basic vaccination series is very low in the study area. Initiatives that enhance women's autonomy within the household and that promote healthy timing and spacing of pregnancies may help in improving child health through vaccination.

  2. Development of a transformation model to derive general population-based utility: Mapping the pruritus-visual analog scale (VAS) to the EQ-5D utility.

    PubMed

    Park, Sun-Young; Park, Eun-Ja; Suh, Hae Sun; Ha, Dongmun; Lee, Eui-Kyung

    2017-08-01

    Although nonpreference-based disease-specific measures are widely used in clinical studies, they cannot generate utilities for economic evaluation. A solution to this problem is to estimate utilities from disease-specific instruments using the mapping function. This study aimed to develop a transformation model for mapping the pruritus-visual analog scale (VAS) to the EuroQol 5-Dimension 3-Level (EQ-5D-3L) utility index in pruritus. A cross-sectional survey was conducted with a sample (n = 268) drawn from the general population of South Korea. Data were randomly divided into 2 groups, one for estimating and the other for validating mapping models. To select the best model, we developed and compared 3 separate models using demographic information and the pruritus-VAS as independent variables. The predictive performance was assessed using the mean absolute deviation and root mean square error in a separate dataset. Among the 3 models, model 2 using age, age squared, sex, and the pruritus-VAS as independent variables had the best performance based on the goodness of fit and model simplicity, with a log likelihood of 187.13. The 3 models had similar precision errors based on mean absolute deviation and root mean square error in the validation dataset. No statistically significant difference was observed between the mean observed and predicted values in all models. In conclusion, model 2 was chosen as the preferred mapping model. Outcomes measured as the pruritus-VAS can be transformed into the EQ-5D-3L utility index using this mapping model, which makes an economic evaluation possible when only pruritus-VAS data are available. © 2017 John Wiley & Sons, Ltd.

  3. Bioavailability study of dronabinol oral solution versus dronabinol capsules in healthy volunteers

    PubMed Central

    Parikh, Neha; Kramer, William G; Khurana, Varun; Cognata Smith, Christina; Vetticaden, Santosh

    2016-01-01

    Background Dronabinol, a pharmaceutical Δ-9-tetrahydrocannabinol, was originally developed as an oral capsule. This study evaluated the bioavailability of a new formulation, dronabinol oral solution, versus a dronabinol capsule formulation. Methods In an open-label, four-period, single-dose, crossover study, healthy volunteers were randomly assigned to one of two treatment sequences (T-R-T-R and R-T-R-T; T = dronabinol 4.25 mg oral solution and R = dronabinol 5 mg capsule) under fasted conditions, with a minimum 7-day washout period between doses. Analyses were performed on venous blood samples drawn 15 minutes to 48 hours postdose, and dronabinol concentrations were assayed by liquid chromatography–tandem mass spectrometry. Results Fifty-one of 52 individuals had pharmacokinetic data for analysis. The 90% confidence interval of the geometric mean ratio (oral solution/capsule) for dronabinol was within the 80%–125% bioequivalence range for area under the plasma concentration–time curve (AUC) from time zero to last measurable concentration (AUC0–t) and AUC from time zero to infinity (AUC0–∞). Maximum plasma concentration was also bioequivalent for the two dronabinol formulations. Intraindividual variability in AUC0–∞ was >60% lower for dronabinol oral solution 4.25 mg versus dronabinol capsule 5 mg. Plasma dronabinol concentrations were detected within 15 minutes postdose in 100% of patients when receiving oral solution and in <25% of patients when receiving capsules. Conclusion Single-dose dronabinol oral solution 4.25 mg was bioequivalent to dronabinol capsule 5 mg under fasted conditions. Dronabinol oral solution formulation may provide an easy-to-swallow administration option with lower intraindividual variability as well as more rapid absorption versus dronabinol capsules. PMID:27785111

  4. Mechanics and Morphology of Silk Drawn from Anesthetized Spiders

    NASA Astrophysics Data System (ADS)

    Madsen, B.; Vollrath, F.

    CO2 and N2 anesthetized Nephila spiders produced dragline silk with mechanical properties that differed from control silk as a function of time under anesthesia. Silk from CO2 spiders had a significantly lower breaking strain and breaking energy, significantly higher initial modulus, and marginally lower breaking stress. At the onset of anesthesia the silk diameter became highly variable. During deep anesthesia silk either became thinner or retained cross-section but fibrillated.

  5. A Note on Asymptotic Joint Distribution of the Eigenvalues of a Noncentral Multivariate F Matrix.

    DTIC Science & Technology

    1984-11-01

    Krishnaiah (1982). Now, let us consider the samples drawn from the k multivariate normal popuiejons. Let (Xlt....Xpt) denote the mean vector of the t...to maltivariate problems. Sankh-ya, 4, 381-39(s. (71 KRISHNAIAH , P. R. (1982). Selection of variables in discrimlnant analysis. In Handbook of...Statistics, Volume 2 (P. R. Krishnaiah , editor), 805-820. North-Holland Publishing Company. 6. Unclassifie INSTRUCTIONS REPORT DOCUMENTATION PAGE

  6. Exploiting Data Missingness in Bayesian Network Modeling

    NASA Astrophysics Data System (ADS)

    Rodrigues de Morais, Sérgio; Aussem, Alex

    This paper proposes a framework built on the use of Bayesian networks (BN) for representing statistical dependencies between the existing random variables and additional dummy boolean variables, which represent the presence/absence of the respective random variable value. We show how augmenting the BN with these additional variables helps pinpoint the mechanism through which missing data contributes to the classification task. The missing data mechanism is thus explicitly taken into account to predict the class variable using the data at hand. Extensive experiments on synthetic and real-world incomplete data sets reveals that the missingness information improves classification accuracy.

  7. Health benefits for the terminally ill: reality and perception.

    PubMed

    Gabel, J R; Hurst, K M; Hunt, K A

    1998-01-01

    This paper examines the availability and scope of hospice benefits as well as employers' attitudes and knowledge about care for the terminally ill. Data are drawn from a national random sample of 1,502 employers with 200 or more workers and from focus groups with employee benefits managers and their insurance advisers, brokers, and consultants. Major findings are that 83 percent of employers offer explicit hospice benefits, with most other firms covering hospice through high-cost case management. Most employers support the concept of hospice care because they believe that it reduces medical expenses.

  8. Reconsidering the Rhizome: A Textual Analysis of Web Search Engines as Gatekeepers of the Internet

    NASA Astrophysics Data System (ADS)

    Hess, A.

    Critical theorists have often drawn from Deleuze and Guattari's notion of the rhizome when discussing the potential of the Internet. While the Internet may structurally appear as a rhizome, its day-to-day usage by millions via search engines precludes experiencing the random interconnectedness and potential democratizing function. Through a textual analysis of four search engines, I argue that Web searching has grown hierarchies, or "trees," that organize data in tracts of knowledge and place users in marketing niches rather than assist in the development of new knowledge.

  9. Nonrecurrence and Bell-like inequalities

    NASA Astrophysics Data System (ADS)

    Danforth, Douglas G.

    2017-12-01

    The general class, Λ, of Bell hidden variables is composed of two subclasses ΛR and ΛN such that ΛR⋃ΛN = Λ and ΛR∩ ΛN = {}. The class ΛN is very large and contains random variables whose domain is the continuum, the reals. There are an uncountable infinite number of reals. Every instance of a real random variable is unique. The probability of two instances being equal is zero, exactly zero. ΛN induces sample independence. All correlations are context dependent but not in the usual sense. There is no "spooky action at a distance". Random variables, belonging to ΛN, are independent from one experiment to the next. The existence of the class ΛN makes it impossible to derive any of the standard Bell inequalities used to define quantum entanglement.

  10. Perturbed effects at radiation physics

    NASA Astrophysics Data System (ADS)

    Külahcı, Fatih; Şen, Zekâi

    2013-09-01

    Perturbation methodology is applied in order to assess the linear attenuation coefficient, mass attenuation coefficient and cross-section behavior with random components in the basic variables such as the radiation amounts frequently used in the radiation physics and chemistry. Additionally, layer attenuation coefficient (LAC) and perturbed LAC (PLAC) are proposed for different contact materials. Perturbation methodology provides opportunity to obtain results with random deviations from the average behavior of each variable that enters the whole mathematical expression. The basic photon intensity variation expression as the inverse exponential power law (as Beer-Lambert's law) is adopted for perturbation method exposition. Perturbed results are presented not only in terms of the mean but additionally the standard deviation and the correlation coefficients. Such perturbation expressions provide one to assess small random variability in basic variables.

  11. Analysis of stationary and dynamic factors affecting highway accident occurrence: A dynamic correlated grouped random parameters binary logit approach.

    PubMed

    Fountas, Grigorios; Sarwar, Md Tawfiq; Anastasopoulos, Panagiotis Ch; Blatt, Alan; Majka, Kevin

    2018-04-01

    Traditional accident analysis typically explores non-time-varying (stationary) factors that affect accident occurrence on roadway segments. However, the impact of time-varying (dynamic) factors is not thoroughly investigated. This paper seeks to simultaneously identify pre-crash stationary and dynamic factors of accident occurrence, while accounting for unobserved heterogeneity. Using highly disaggregate information for the potential dynamic factors, and aggregate data for the traditional stationary elements, a dynamic binary random parameters (mixed) logit framework is employed. With this approach, the dynamic nature of weather-related, and driving- and pavement-condition information is jointly investigated with traditional roadway geometric and traffic characteristics. To additionally account for the combined effect of the dynamic and stationary factors on the accident occurrence, the developed random parameters logit framework allows for possible correlations among the random parameters. The analysis is based on crash and non-crash observations between 2011 and 2013, drawn from urban and rural highway segments in the state of Washington. The findings show that the proposed methodological framework can account for both stationary and dynamic factors affecting accident occurrence probabilities, for panel effects, for unobserved heterogeneity through the use of random parameters, and for possible correlation among the latter. The comparative evaluation among the correlated grouped random parameters, the uncorrelated random parameters logit models, and their fixed parameters logit counterpart, demonstrate the potential of the random parameters modeling, in general, and the benefits of the correlated grouped random parameters approach, specifically, in terms of statistical fit and explanatory power. Published by Elsevier Ltd.

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

    Schmidt, Edward G.; Hemen, Brian; Rogalla, Danielle

    We have obtained VR photometry of 282 Cepheid variable star candidates from the northern part of the All Sky Automated Survey (ASAS). These together with data from the ASAS and the Northern Sky Variability Survey (NSVS) were used to redetermine the periods of the stars. We divided the stars into four groups based on location in a plot of mean color, (V-R), versus period. Two of the groups fell within the region of the diagram containing known type II Cepheids and yielded 14 new highly probable type II Cepheids. The properties of the remaining stars in these two groups aremore » discussed but their nature remains uncertain. Unexplained differences exist between the sample of stars studied here and a previous sample drawn from the NSVS by Akerlof et al. This suggests serious biases in the identification of variables in different surveys.« less

  13. The statistical pitfalls of the partially randomized preference design in non-blinded trials of psychological interventions.

    PubMed

    Gemmell, Isla; Dunn, Graham

    2011-03-01

    In a partially randomized preference trial (PRPT) patients with no treatment preference are allocated to groups at random, but those who express a preference receive the treatment of their choice. It has been suggested that the design can improve the external and internal validity of trials. We used computer simulation to illustrate the impact that an unmeasured confounder could have on the results and conclusions drawn from a PRPT. We generated 4000 observations ("patients") that reflected the distribution of the Beck Depression Index (DBI) in trials of depression. Half were randomly assigned to a randomized controlled trial (RCT) design and half were assigned to a PRPT design. In the RCT, "patients" were evenly split between treatment and control groups; whereas in the preference arm, to reflect patient choice, 87.5% of patients were allocated to the experimental treatment and 12.5% to the control. Unadjusted analyses of the PRPT data consistently overestimated the treatment effect and its standard error. This lead to Type I errors when the true treatment effect was small and Type II errors when the confounder effect was large. The PRPT design is not recommended as a method of establishing an unbiased estimate of treatment effect due to the potential influence of unmeasured confounders. Copyright © 2011 John Wiley & Sons, Ltd.

  14. Climate and landscape explain richness patterns depending on the type of species' distribution data

    NASA Astrophysics Data System (ADS)

    Tsianou, Mariana A.; Koutsias, Nikolaos; Mazaris, Antonios D.; Kallimanis, Athanasios S.

    2016-07-01

    Understanding the patterns of species richness and their environmental drivers, remains a central theme in ecological research and especially in the continental scales where many conservation decisions are made. Here, we analyzed the patterns of species richness from amphibians, reptiles and mammals at the EU level. We used two different data sources for each taxon: expert-drawn species range maps, and presence/absence atlases. As environmental drivers, we considered climate and land cover. Land cover is increasingly the focus of research, but there still is no consensus on how to classify land cover to distinct habitat classes, so we analyzed the CORINE land cover data with three different levels of thematic resolution (resolution of classification scheme ˗ less to more detailed). We found that the two types of species richness data explored in this study yielded different richness maps. Although, we expected expert-drawn range based estimates of species richness to exceed those from atlas data (due to the assumption that species are present in all locations throughout their region), we found that in many cases the opposite is true (the extreme case is the reptiles where more than half of the atlas based estimates were greater than the expert-drawn range based estimates). Also, we detected contrasting information on the richness drivers of biodiversity patterns depending on the dataset used. For atlas based richness estimates, landscape attributes played more important role than climate while for expert-drawn range based richness estimates climatic variables were more important (for the ectothermic amphibians and reptiles). Finally we found that the thematic resolution of the land cover classification scheme, also played a role in quantifying the effect of land cover diversity, with more detailed thematic resolution increasing the relative contribution of landscape attributes in predicting species richness.

  15. Assessing the accuracy and stability of variable selection methods for random forest modeling in ecology

    EPA Science Inventory

    Random forest (RF) modeling has emerged as an important statistical learning method in ecology due to its exceptional predictive performance. However, for large and complex ecological datasets there is limited guidance on variable selection methods for RF modeling. Typically, e...

  16. An assessment of environmental literacy and analysis of predictors of responsible environmental behavior held by secondary teachers in Hualien County of Taiwan

    NASA Astrophysics Data System (ADS)

    Hsu, Shih-Jang

    The major purpose of this study was to determine the relative contribution of nine variables in predicting teachers' responsible environmental behavior (REB). The theoretic framework of this study was based on the Hines model, the Hungerford and Volk model, and the environmental literacy framework proposed by Environmental Literacy Assessment Consortium. A nine-page instrument was administered by mailed questionnaire to 300 randomly selected secondary teachers in Hualien County of Taiwan with a 78.7% response rate. Correlation and stepwise multiple regression analyses were conducted. The following conclusions were drawn: (1) For all the respondents, all the nine environmental literacy variables were significant correlates of REB. These correlates included: perceived knowledge of environmental action strategies (KNOW; r =.46), intention to act (IA; r =.46), perceived skill in using environmental action strategies (SKILL; r =.45), perceived knowledge of environmental problems and issues (KISSU; r =.34), environmental sensitivity (r =.28), environmental responsibility (r =.27), perceived knowledge of ecology and environmental science (r =.27), locus of control (r =.27), and environmental attitudes (r =.21). (2) When only the nine environmental literacy variables were considered, the most parsimonious set of predictors of REB for all the teachers included: (a) KNOW, (Rsp2 =.2116); (b) IA, (Rsp2 =.0916); and (c) SKILL, (Rsp2 =.0205). For the urban teachers, the most parsimonious set of predictors included: (a) IA (Rsp2 =.2559); (b) SKILL (Rsp2.0926); and (c) environmental responsibility (Rsp2 =.0219). For the rural teachers, the most parsimonious set of predictors included: (a) KNOW (Rsp2 =.1872); (b) IA (Rsp2 =.0816); and (c) KISSU (Rsp2 =.0318). (3) When the environmental literacy variables as well as demographic and experience variables were considered, the most parsimonious set of predictors for all the teachers included: (a) KNOW, (Rsp2 =.2834); (b) IA, (Rsp2 =.0696); (c) area of residence, (Rsp2 =.0174); and (d) SKILL, (Rsp2 =.0163). For the urban teachers, the most parsimonious set of predictors included: (a) IA (Rsp2 =.3199); (b) SKILL (Rsp2 =.0840); (c) major sources of environmental information (Rsp2 =.0432); and (d) membership in environmental organizations, (Rsp2 =.0240). Implications for environmental education program development and instructional practice were presented. Recommendations for further research were also provided.

  17. Random function representation of stationary stochastic vector processes for probability density evolution analysis of wind-induced structures

    NASA Astrophysics Data System (ADS)

    Liu, Zhangjun; Liu, Zenghui

    2018-06-01

    This paper develops a hybrid approach of spectral representation and random function for simulating stationary stochastic vector processes. In the proposed approach, the high-dimensional random variables, included in the original spectral representation (OSR) formula, could be effectively reduced to only two elementary random variables by introducing the random functions that serve as random constraints. Based on this, a satisfactory simulation accuracy can be guaranteed by selecting a small representative point set of the elementary random variables. The probability information of the stochastic excitations can be fully emerged through just several hundred of sample functions generated by the proposed approach. Therefore, combined with the probability density evolution method (PDEM), it could be able to implement dynamic response analysis and reliability assessment of engineering structures. For illustrative purposes, a stochastic turbulence wind velocity field acting on a frame-shear-wall structure is simulated by constructing three types of random functions to demonstrate the accuracy and efficiency of the proposed approach. Careful and in-depth studies concerning the probability density evolution analysis of the wind-induced structure have been conducted so as to better illustrate the application prospects of the proposed approach. Numerical examples also show that the proposed approach possesses a good robustness.

  18. The living Drake equation of the Tau Zero Foundation

    NASA Astrophysics Data System (ADS)

    Maccone, Claudio

    2011-03-01

    The living Drake equation is our statistical generalization of the Drake equation such that it can take into account any number of factors. This new result opens up the possibility to enrich the equation by inserting more new factors as long as the scientific learning increases. The adjective "Living" refers just to this continuous enrichment of the Drake equation and is the goal of a new research project that the Tau Zero Foundation has entrusted to this author as the discoverer of the statistical Drake equation described hereafter. From a simple product of seven positive numbers, the Drake equation is now turned into the product of seven positive random variables. We call this "the Statistical Drake Equation". The mathematical consequences of this transformation are then derived. The proof of our results is based on the Central Limit Theorem (CLT) of Statistics. In loose terms, the CLT states that the sum of any number of independent random variables, each of which may be arbitrarily distributed, approaches a Gaussian (i.e. normal) random variable. This is called the Lyapunov form of the CLT, or the Lindeberg form of the CLT, depending on the mathematical constraints assumed on the third moments of the various probability distributions. In conclusion, we show that: The new random variable N, yielding the number of communicating civilizations in the Galaxy, follows the lognormal distribution. Then, the mean value, standard deviation, mode, median and all the moments of this lognormal N can be derived from the means and standard deviations of the seven input random variables. In fact, the seven factors in the ordinary Drake equation now become seven independent positive random variables. The probability distribution of each random variable may be arbitrary. The CLT in the so-called Lyapunov or Lindeberg forms (that both do not assume the factors to be identically distributed) allows for that. In other words, the CLT "translates" into our statistical Drake equation by allowing an arbitrary probability distribution for each factor. This is both physically realistic and practically very useful, of course. An application of our statistical Drake equation then follows. The (average) distance between any two neighbouring and communicating civilizations in the Galaxy may be shown to be inversely proportional to the cubic root of N. Then, this distance now becomes a new random variable. We derive the relevant probability density function, apparently previously unknown (dubbed "Maccone distribution" by Paul Davies). Data Enrichment Principle. It should be noticed that any positive number of random variables in the statistical Drake equation is compatible with the CLT. So, our generalization allows for many more factors to be added in the future as long as more refined scientific knowledge about each factor will be known to the scientists. This capability to make room for more future factors in the statistical Drake equation we call the "Data Enrichment Principle", and regard as the key to more profound, future results in Astrobiology and SETI.

  19. Is ginger effective for the treatment of irritable bowel syndrome? A double blind randomized controlled pilot trial.

    PubMed

    van Tilburg, Miranda A L; Palsson, Olafur S; Ringel, Yehuda; Whitehead, William E

    2014-02-01

    Ginger is one of the most commonly used herbal medicines for irritable bowel syndrome (IBS) but no data exists about its effectiveness. Double blind randomized controlled trial. University of North Carolina, Chapel Hill, North Carolina, USA. Forty-five IBS patients were randomly assigned to three groups: placebo, 1g of ginger, and 2g of ginger daily for 28 days. The IBS severity scale (IBS-SS) was administered, as well as adequate relief of symptoms scale. A responder was defined as having at least 25% reduction in IBS-SS post-treatment. There were 57.1% responders to placebo, 46.7% to 1g and 33.3% to 2g of ginger. Adequate relief was reported by 53.3% on placebo and 53.3% in both ginger groups combined. Side effects were mild and reported by 35.7% in the placebo and 16.7% in the ginger groups. This double blind randomized controlled pilot study suggests ginger is well tolerated but did not perform better than placebo. Larger trials are needed before any definitive conclusions can be drawn. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Piezoresistivity of mechanically drawn single-walled carbon nanotube (SWCNT) thin films-: mechanism and optimizing principle

    NASA Astrophysics Data System (ADS)

    Obitayo, Waris

    The individual carbon nanotube (CNT) based strain sensors have been found to have excellent piezoresistive properties with a reported gauge factor (GF) of up to 3000. This GF on the other hand, has been shown to be structurally dependent on the nanotubes. In contrast, to individual CNT based strain sensors, the ensemble CNT based strain sensors have very low GFs e.g. for a single walled carbon nanotube (SWCNT) thin film strain sensor, GF is ~1. As a result, studies which are mostly numerical/analytical have revealed the dependence of piezoresistivity on key parameters like concentration, orientation, length and diameter, aspect ratio, energy barrier height and Poisson ratio of polymer matrix. The fundamental understanding of the piezoresistive mechanism in an ensemble CNT based strain sensor still remains unclear, largely due to discrepancies in the outcomes of these numerical studies. Besides, there have been little or no experimental confirmation of these studies. The goal of my PhD is to study the mechanism and the optimizing principle of a SWCNT thin film strain sensor and provide experimental validation of the numerical/analytical investigations. The dependence of the piezoresistivity on key parameters like orientation, network density, bundle diameter (effective tunneling area), and length is studied, and how one can effectively optimize the piezoresistive behavior of a SWCNT thin film strain sensors. To reach this goal, my first research accomplishment involves the study of orientation of SWCNTs and its effect on the piezoresistivity of mechanically drawn SWCNT thin film based piezoresistive sensors. Using polarized Raman spectroscopy analysis and coupled electrical-mechanical test, a quantitative relationship between the strain sensitivity and SWCNT alignment order parameter was established. As compared to randomly oriented SWCNT thin films, the one with draw ratio of 3.2 exhibited ~6x increase on the GF. My second accomplishment involves studying the influence of the network density on the piezoresistivity of mechanically drawn SWCNT thin films. Mechanically drawn SWCNT thin films with different layer (or thickness) e.g. 1-layer, 3-layer, 10-layer and 20-layer SWCNT thin films were prepared to understand the variation of SWCNT network density as well as the alignment of SWCNTs on the strain sensitivity. The less entangled SWCNT bundles observed in the sparse network density (1- layer and 3-layer SWCNT thin films) allows for easy alignment and the best gauge factors. As compared to the randomly oriented SWCNT thin films, the one with draw ratio of 3.2 exhibited ~8x increase on the GF for the 1-layer SWCNT thin films while the 20-layer SWCNT thin films exhibited ~3x increase in the GF. My third accomplishment examines the effect of SWCNT bundles with different diameters on the piezoresistive behavior of mechanically drawn SWCNT thin films. SWCNT thin film network of sparse morphology (1-layer) with different bundle sizes were prepared by varying the sonication duration e.g. S0.5hr, S4hr, S10hr and S20hr and using spraying coating. The GF increased by a factor of ~10 when the randomly oriented SWCNT thin film was stretched to a draw ratio of 3.2 for the S0.5hr SWCNT thin films and by a factor of ~2 for the S20hr SWCNT thin films. Three main mechanisms were attributed to this behavior e.g. effect of concentration of exfoliated nanotubes, bundle reduction due to mechanical stretching, and influence of bundle length on the alignment of SWCNTs. Furthermore, information about the average length and length distribution is very essential when investigating the influence of individual nanotube length on the strain sensitivity. With that in mind, we would use our previously developed preparative ultracentrifuge method (PUM), and our newly developed gel electrophoresis and simultaneous Raman and photoluminescence spectroscopy (GEP-SRSPL) to characterize the average length and length distribution of individual SWCNTs respectively.

  1. A Unifying Probability Example.

    ERIC Educational Resources Information Center

    Maruszewski, Richard F., Jr.

    2002-01-01

    Presents an example from probability and statistics that ties together several topics including the mean and variance of a discrete random variable, the binomial distribution and its particular mean and variance, the sum of independent random variables, the mean and variance of the sum, and the central limit theorem. Uses Excel to illustrate these…

  2. Variable selection with random forest: Balancing stability, performance, and interpretation in ecological and environmental modeling

    EPA Science Inventory

    Random forest (RF) is popular in ecological and environmental modeling, in part, because of its insensitivity to correlated predictors and resistance to overfitting. Although variable selection has been proposed to improve both performance and interpretation of RF models, it is u...

  3. The Statistical Drake Equation

    NASA Astrophysics Data System (ADS)

    Maccone, Claudio

    2010-12-01

    We provide the statistical generalization of the Drake equation. From a simple product of seven positive numbers, the Drake equation is now turned into the product of seven positive random variables. We call this "the Statistical Drake Equation". The mathematical consequences of this transformation are then derived. The proof of our results is based on the Central Limit Theorem (CLT) of Statistics. In loose terms, the CLT states that the sum of any number of independent random variables, each of which may be ARBITRARILY distributed, approaches a Gaussian (i.e. normal) random variable. This is called the Lyapunov Form of the CLT, or the Lindeberg Form of the CLT, depending on the mathematical constraints assumed on the third moments of the various probability distributions. In conclusion, we show that: The new random variable N, yielding the number of communicating civilizations in the Galaxy, follows the LOGNORMAL distribution. Then, as a consequence, the mean value of this lognormal distribution is the ordinary N in the Drake equation. The standard deviation, mode, and all the moments of this lognormal N are also found. The seven factors in the ordinary Drake equation now become seven positive random variables. The probability distribution of each random variable may be ARBITRARY. The CLT in the so-called Lyapunov or Lindeberg forms (that both do not assume the factors to be identically distributed) allows for that. In other words, the CLT "translates" into our statistical Drake equation by allowing an arbitrary probability distribution for each factor. This is both physically realistic and practically very useful, of course. An application of our statistical Drake equation then follows. The (average) DISTANCE between any two neighboring and communicating civilizations in the Galaxy may be shown to be inversely proportional to the cubic root of N. Then, in our approach, this distance becomes a new random variable. We derive the relevant probability density function, apparently previously unknown and dubbed "Maccone distribution" by Paul Davies. DATA ENRICHMENT PRINCIPLE. It should be noticed that ANY positive number of random variables in the Statistical Drake Equation is compatible with the CLT. So, our generalization allows for many more factors to be added in the future as long as more refined scientific knowledge about each factor will be known to the scientists. This capability to make room for more future factors in the statistical Drake equation, we call the "Data Enrichment Principle," and we regard it as the key to more profound future results in the fields of Astrobiology and SETI. Finally, a practical example is given of how our statistical Drake equation works numerically. We work out in detail the case, where each of the seven random variables is uniformly distributed around its own mean value and has a given standard deviation. For instance, the number of stars in the Galaxy is assumed to be uniformly distributed around (say) 350 billions with a standard deviation of (say) 1 billion. Then, the resulting lognormal distribution of N is computed numerically by virtue of a MathCad file that the author has written. This shows that the mean value of the lognormal random variable N is actually of the same order as the classical N given by the ordinary Drake equation, as one might expect from a good statistical generalization.

  4. Random effects coefficient of determination for mixed and meta-analysis models

    PubMed Central

    Demidenko, Eugene; Sargent, James; Onega, Tracy

    2011-01-01

    The key feature of a mixed model is the presence of random effects. We have developed a coefficient, called the random effects coefficient of determination, Rr2, that estimates the proportion of the conditional variance of the dependent variable explained by random effects. This coefficient takes values from 0 to 1 and indicates how strong the random effects are. The difference from the earlier suggested fixed effects coefficient of determination is emphasized. If Rr2 is close to 0, there is weak support for random effects in the model because the reduction of the variance of the dependent variable due to random effects is small; consequently, random effects may be ignored and the model simplifies to standard linear regression. The value of Rr2 apart from 0 indicates the evidence of the variance reduction in support of the mixed model. If random effects coefficient of determination is close to 1 the variance of random effects is very large and random effects turn into free fixed effects—the model can be estimated using the dummy variable approach. We derive explicit formulas for Rr2 in three special cases: the random intercept model, the growth curve model, and meta-analysis model. Theoretical results are illustrated with three mixed model examples: (1) travel time to the nearest cancer center for women with breast cancer in the U.S., (2) cumulative time watching alcohol related scenes in movies among young U.S. teens, as a risk factor for early drinking onset, and (3) the classic example of the meta-analysis model for combination of 13 studies on tuberculosis vaccine. PMID:23750070

  5. Correlated resistive/capacitive state variability in solid TiO2 based memory devices

    NASA Astrophysics Data System (ADS)

    Li, Qingjiang; Salaoru, Iulia; Khiat, Ali; Xu, Hui; Prodromakis, Themistoklis

    2017-05-01

    In this work, we experimentally demonstrated the correlated resistive/capacitive switching and state variability in practical TiO2 based memory devices. Based on filamentary functional mechanism, we argue that the impedance state variability stems from the randomly distributed defects inside the oxide bulk. Finally, our assumption was verified via a current percolation circuit model, by taking into account of random defects distribution and coexistence of memristor and memcapacitor.

  6. Algebraic Functions of H-Functions with Specific Dependency Structure.

    DTIC Science & Technology

    1984-05-01

    a study of its characteristic function. Such analysis is reproduced in books by Springer (17), Anderson (23), Feller (34,35), Mood and Graybill (52...following linearity property for expectations of jointly distributed random variables is derived. r 1 Theorem 1.1: If X and Y are real random variables...appear in American Journal of Mathematical and Management Science. 13. Mathai, A.M., and R.K. Saxena, "On linear combinations of stochastic variables

  7. The Statistical Fermi Paradox

    NASA Astrophysics Data System (ADS)

    Maccone, C.

    In this paper is provided the statistical generalization of the Fermi paradox. The statistics of habitable planets may be based on a set of ten (and possibly more) astrobiological requirements first pointed out by Stephen H. Dole in his book Habitable planets for man (1964). The statistical generalization of the original and by now too simplistic Dole equation is provided by replacing a product of ten positive numbers by the product of ten positive random variables. This is denoted the SEH, an acronym standing for “Statistical Equation for Habitables”. The proof in this paper is based on the Central Limit Theorem (CLT) of Statistics, stating that the sum of any number of independent random variables, each of which may be ARBITRARILY distributed, approaches a Gaussian (i.e. normal) random variable (Lyapunov form of the CLT). It is then shown that: 1. The new random variable NHab, yielding the number of habitables (i.e. habitable planets) in the Galaxy, follows the log- normal distribution. By construction, the mean value of this log-normal distribution is the total number of habitable planets as given by the statistical Dole equation. 2. The ten (or more) astrobiological factors are now positive random variables. The probability distribution of each random variable may be arbitrary. The CLT in the so-called Lyapunov or Lindeberg forms (that both do not assume the factors to be identically distributed) allows for that. In other words, the CLT "translates" into the SEH by allowing an arbitrary probability distribution for each factor. This is both astrobiologically realistic and useful for any further investigations. 3. By applying the SEH it is shown that the (average) distance between any two nearby habitable planets in the Galaxy may be shown to be inversely proportional to the cubic root of NHab. This distance is denoted by new random variable D. The relevant probability density function is derived, which was named the "Maccone distribution" by Paul Davies in 2008. 4. A practical example is then given of how the SEH works numerically. Each of the ten random variables is uniformly distributed around its own mean value as given by Dole (1964) and a standard deviation of 10% is assumed. The conclusion is that the average number of habitable planets in the Galaxy should be around 100 million ±200 million, and the average distance in between any two nearby habitable planets should be about 88 light years ±40 light years. 5. The SEH results are matched against the results of the Statistical Drake Equation from reference 4. As expected, the number of currently communicating ET civilizations in the Galaxy turns out to be much smaller than the number of habitable planets (about 10,000 against 100 million, i.e. one ET civilization out of 10,000 habitable planets). The average distance between any two nearby habitable planets is much smaller that the average distance between any two neighbouring ET civilizations: 88 light years vs. 2000 light years, respectively. This means an ET average distance about 20 times higher than the average distance between any pair of adjacent habitable planets. 6. Finally, a statistical model of the Fermi Paradox is derived by applying the above results to the coral expansion model of Galactic colonization. The symbolic manipulator "Macsyma" is used to solve these difficult equations. A new random variable Tcol, representing the time needed to colonize a new planet is introduced, which follows the lognormal distribution, Then the new quotient random variable Tcol/D is studied and its probability density function is derived by Macsyma. Finally a linear transformation of random variables yields the overall time TGalaxy needed to colonize the whole Galaxy. We believe that our mathematical work in deriving this STATISTICAL Fermi Paradox is highly innovative and fruitful for the future.

  8. The Role of Binarity in the Angular Momentum Evolution of M Dwarfs

    NASA Astrophysics Data System (ADS)

    Stauffer, John; Rebull, Luisa; K2 clusters team

    2018-01-01

    We have analysed K2 light curves for of order a thousand low mass stars in each of the 8 Myr old Upper Sco association, the 125 Myr age Pleiades open cluster and the ~700 Myr old Praesepe cluster. A very large fraction of these stars show well-determined rotation periods with K2, and where the star is a binary, we usually are able to determine periods for both stars. In Upper Sco, where there are ~150 M dwarf binaries with K2 light curves, the binary stars have periods that are much shorter on average and much closer to each other than would be true if drawn at random from the Upper Sco M dwarf single stars. The same is true in the Pleiades,though the size of the differences from the single M dwarf population is smaller. By Praesepe age, the M dwarf binaries are still somewhat rapidly rotating but their period differences are not significantly different from what would be true if drawn by chance from the singles.

  9. Concept Learning of Young Children as a Function of Sibling Relationships to the Teacher. Report from the Project on Variables and Processes in Cognitive Learning.

    ERIC Educational Resources Information Center

    Circirelli, Victor G.

    This study attempted to answer the question: Is a sibling relationship associated with concept learning of a younger child taught by an older child? Each of the 120 First Grade children in the study had an older sibling in Third Grade; equal samples of 30 sibling pairs were drawn from the population of boys with older sisters, boys with older…

  10. On the distribution of a product of N Gaussian random variables

    NASA Astrophysics Data System (ADS)

    Stojanac, Željka; Suess, Daniel; Kliesch, Martin

    2017-08-01

    The product of Gaussian random variables appears naturally in many applications in probability theory and statistics. It has been known that the distribution of a product of N such variables can be expressed in terms of a Meijer G-function. Here, we compute a similar representation for the corresponding cumulative distribution function (CDF) and provide a power-log series expansion of the CDF based on the theory of the more general Fox H-functions. Numerical computations show that for small values of the argument the CDF of products of Gaussians is well approximated by the lowest orders of this expansion. Analogous results are also shown for the absolute value as well as the square of such products of N Gaussian random variables. For the latter two settings, we also compute the moment generating functions in terms of Meijer G-functions.

  11. Random parameter models for accident prediction on two-lane undivided highways in India.

    PubMed

    Dinu, R R; Veeraragavan, A

    2011-02-01

    Generalized linear modeling (GLM), with the assumption of Poisson or negative binomial error structure, has been widely employed in road accident modeling. A number of explanatory variables related to traffic, road geometry, and environment that contribute to accident occurrence have been identified and accident prediction models have been proposed. The accident prediction models reported in literature largely employ the fixed parameter modeling approach, where the magnitude of influence of an explanatory variable is considered to be fixed for any observation in the population. Similar models have been proposed for Indian highways too, which include additional variables representing traffic composition. The mixed traffic on Indian highways comes with a lot of variability within, ranging from difference in vehicle types to variability in driver behavior. This could result in variability in the effect of explanatory variables on accidents across locations. Random parameter models, which can capture some of such variability, are expected to be more appropriate for the Indian situation. The present study is an attempt to employ random parameter modeling for accident prediction on two-lane undivided rural highways in India. Three years of accident history, from nearly 200 km of highway segments, is used to calibrate and validate the models. The results of the analysis suggest that the model coefficients for traffic volume, proportion of cars, motorized two-wheelers and trucks in traffic, and driveway density and horizontal and vertical curvatures are randomly distributed across locations. The paper is concluded with a discussion on modeling results and the limitations of the present study. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. Between-Group Variation in Female Dispersal, Kin Composition of Groups, and Proximity Patterns in a Black-and-White Colobus Monkey (Colobus vellerosus)

    PubMed Central

    Wikberg, Eva C.; Sicotte, Pascale; Campos, Fernando A.; Ting, Nelson

    2012-01-01

    A growing body of evidence shows within-population variation in natal dispersal, but the effects of such variation on social relationships and the kin composition of groups remain poorly understood. We investigate the link between dispersal, the kin composition of groups, and proximity patterns in a population of black-and-white colobus (Colobus vellerosus) that shows variation in female dispersal. From 2006 to 2011, we collected behavioral data, demographic data, and fecal samples of 77 males and 92 females residing in eight groups at Boabeng-Fiema, Ghana. A combination of demographic data and a genetic network analysis showed that although philopatry was female-biased, only about half of the females resided in their natal groups. Only one group contained female-female dyads with higher average relatedness than randomly drawn animals of both sexes from the same group. Despite between-group variation in female dispersal and kin composition, female-female dyads in most of the study groups had higher proximity scores than randomly drawn dyads from the same group. We conclude that groups fall along a continuum from female dispersed, not kin-based, and not bonded to female philopatric, kin-based, and bonded. We found only partial support for the predicted link between dispersal, kin composition, and social relationships. In contrast to most mammals where the kin composition of groups is a good predictor of the quality of female-female relationships, this study provides further support for the notion that kinship is not necessary for the development and maintenance of social bonds in some gregarious species. PMID:23144951

  13. Bias, Confounding, and Interaction: Lions and Tigers, and Bears, Oh My!

    PubMed

    Vetter, Thomas R; Mascha, Edward J

    2017-09-01

    Epidemiologists seek to make a valid inference about the causal effect between an exposure and a disease in a specific population, using representative sample data from a specific population. Clinical researchers likewise seek to make a valid inference about the association between an intervention and outcome(s) in a specific population, based upon their randomly collected, representative sample data. Both do so by using the available data about the sample variable to make a valid estimate about its corresponding or underlying, but unknown population parameter. Random error in an experiment can be due to the natural, periodic fluctuation or variation in the accuracy or precision of virtually any data sampling technique or health measurement tool or scale. In a clinical research study, random error can be due to not only innate human variability but also purely chance. Systematic error in an experiment arises from an innate flaw in the data sampling technique or measurement instrument. In the clinical research setting, systematic error is more commonly referred to as systematic bias. The most commonly encountered types of bias in anesthesia, perioperative, critical care, and pain medicine research include recall bias, observational bias (Hawthorne effect), attrition bias, misclassification or informational bias, and selection bias. A confounding variable is a factor associated with both the exposure of interest and the outcome of interest. A confounding variable (confounding factor or confounder) is a variable that correlates (positively or negatively) with both the exposure and outcome. Confounding is typically not an issue in a randomized trial because the randomized groups are sufficiently balanced on all potential confounding variables, both observed and nonobserved. However, confounding can be a major problem with any observational (nonrandomized) study. Ignoring confounding in an observational study will often result in a "distorted" or incorrect estimate of the association or treatment effect. Interaction among variables, also known as effect modification, exists when the effect of 1 explanatory variable on the outcome depends on the particular level or value of another explanatory variable. Bias and confounding are common potential explanations for statistically significant associations between exposure and outcome when the true relationship is noncausal. Understanding interactions is vital to proper interpretation of treatment effects. These complex concepts should be consistently and appropriately considered whenever one is not only designing but also analyzing and interpreting data from a randomized trial or observational study.

  14. Random dopant fluctuations and statistical variability in n-channel junctionless FETs

    NASA Astrophysics Data System (ADS)

    Akhavan, N. D.; Umana-Membreno, G. A.; Gu, R.; Antoszewski, J.; Faraone, L.

    2018-01-01

    The influence of random dopant fluctuations on the statistical variability of the electrical characteristics of n-channel silicon junctionless nanowire transistor (JNT) has been studied using three dimensional quantum simulations based on the non-equilibrium Green’s function (NEGF) formalism. Average randomly distributed body doping densities of 2 × 1019, 6 × 1019 and 1 × 1020 cm-3 have been considered employing an atomistic model for JNTs with gate lengths of 5, 10 and 15 nm. We demonstrate that by properly adjusting the doping density in the JNT, a near ideal statistical variability and electrical performance can be achieved, which can pave the way for the continuation of scaling in silicon CMOS technology.

  15. Comparison of work and time estimates by chiropractic physicians with those of medical and osteopathic providers.

    PubMed

    Hess, J A; Mootz, R D

    1999-06-01

    Resource-based relative value scales (RBRVS) have become a standard method for identifying costs and determining reimbursement for physician services. Development of RBRVS systems and methods are reviewed, and the RBRVS concept of physician "work" is defined. Results of work and time inputs from chiropractic physicians are compared with those reported by osteopathic and medical specialties. Last, implications for reimbursement of chiropractic fee services are discussed. Total work, intraservice work, and time inputs for clinical vignettes reported by chiropractic, osteopathic, and medical physicians are compared. Data for chiropractic work and time reports were drawn from a national random sample of chiropractors conducted as part of a 1997 workers' compensation chiropractic fee schedule development project. Medical and osteopathic inputs were drawn from RBRVS research conducted at Harvard University under a federal contract reported in 1990. Both data sets used the same or similar clinical vignettes and similar methods. Comparisons of work and time inputs are made for clinical vignettes to assess whether work reported by chiropractors is of similar magnitude and variability as work reported by other specialties. Chiropractic inputs for vignettes related to evaluation and management services are similar to those reported by medical specialists and osteopathic physicians. The range of variation between chiropractic work input and other specialties is of similar magnitude to that within other specialties. Chiropractors report greater work input for radiologic interpretation and lower work input for manipulation services. Chiropractors seem to perform similar total "work" for evaluation and management services as other specialties. No basis exists for excluding chiropractors from using evaluation and management codes for reimbursement purposes on grounds of dissimilar physician time or work estimates. Greater work input by chiropractors in radiology interpretation may be related to a greater importance placed on findings in care planning. Consistently higher reports for osteopathic work input on manipulation are likely attributable to differences in reference vignettes used in the respective populations. Research with a common reference vignette used for manipulation providers is recommended, as is development of a single generic approach to coding for manipulation services.

  16. Measures of Residual Risk with Connections to Regression, Risk Tracking, Surrogate Models, and Ambiguity

    DTIC Science & Technology

    2015-04-15

    manage , predict, and mitigate the risk in the original variable. Residual risk can be exemplified as a quantification of the improved... the random variable of interest is viewed in concert with a related random vector that helps to manage , predict, and mitigate the risk in the original... manage , predict and mitigate the risk in the original variable. Residual risk can be exemplified as a quantification of the improved situation faced

  17. The influence of contour line size and location on the reproducibility of topographic measurement with the Heidelberg Retina Tomograph.

    PubMed

    Roff, E J; Hosking, S L; Barnes, D A

    2001-05-01

    The recommended contour line (CL) location with the Heidelberg Retina Tomograph (HRT) is on the inner edge of Elschnig's scleral ring. This study investigated HRT parameter reproducibility when: (i) the CL size is altered relative to Elschnig's ring; (ii) the CL is either redrawn or imported between images. Using the HRT, seven 10 degrees images were acquired for 10 normal volunteers and 10 primary open angle glaucoma (POAG) subjects. A CL was drawn on one image for each subject using Elschnig's scleral ring for reference and imported into subsequent images. The CL diameter was then (a) increased by 50 microns; (b) increased by 100 microns; and (c) decreased by 50 microns. To investigate the effect of the method of contour line transfer between images a CL was: (1) defined for one image and imported to 6 subsequent images; (2) drawn separately for each image. Parameter variability improved as the size of the CL increased for the normal group relative to Elschnig's ring but was unchanged in the POAG group. The export/import function (method 1) resulted in better parameter reproducibility than the redrawing method for both groups. The exporting and importing function resulted in better parameter variability for both subject groups and should be used for transferring CLs across images for the same subject. Increasing the overall CL size relative to Elschnig's scleral ring improved the reproducibility of the measured parameters in the normal group. No significant difference in parameter variability was observed for the POAG group. This suggests that the reproducibility of HRT images are affected more by the variation in topography between images than change in CL definition.

  18. Sums and Products of Jointly Distributed Random Variables: A Simplified Approach

    ERIC Educational Resources Information Center

    Stein, Sheldon H.

    2005-01-01

    Three basic theorems concerning expected values and variances of sums and products of random variables play an important role in mathematical statistics and its applications in education, business, the social sciences, and the natural sciences. A solid understanding of these theorems requires that students be familiar with the proofs of these…

  19. A Strategy to Use Soft Data Effectively in Randomized Controlled Clinical Trials.

    ERIC Educational Resources Information Center

    Kraemer, Helena Chmura; Thiemann, Sue

    1989-01-01

    Sees soft data, measures having substantial intrasubject variability due to errors of measurement or response inconsistency, as important measures of response in randomized clinical trials. Shows that using intensive design and slope of response on time as outcome measure maximizes sample retention and decreases within-group variability, thus…

  20. Statistical Analysis for Multisite Trials Using Instrumental Variables with Random Coefficients

    ERIC Educational Resources Information Center

    Raudenbush, Stephen W.; Reardon, Sean F.; Nomi, Takako

    2012-01-01

    Multisite trials can clarify the average impact of a new program and the heterogeneity of impacts across sites. Unfortunately, in many applications, compliance with treatment assignment is imperfect. For these applications, we propose an instrumental variable (IV) model with person-specific and site-specific random coefficients. Site-specific IV…

  1. Bayesian approach to non-Gaussian field statistics for diffusive broadband terahertz pulses.

    PubMed

    Pearce, Jeremy; Jian, Zhongping; Mittleman, Daniel M

    2005-11-01

    We develop a closed-form expression for the probability distribution function for the field components of a diffusive broadband wave propagating through a random medium. We consider each spectral component to provide an individual observation of a random variable, the configurationally averaged spectral intensity. Since the intensity determines the variance of the field distribution at each frequency, this random variable serves as the Bayesian prior that determines the form of the non-Gaussian field statistics. This model agrees well with experimental results.

  2. Optimal estimation of spatially variable recharge and transmissivity fields under steady-state groundwater flow. Part 1. Theory

    NASA Astrophysics Data System (ADS)

    Graham, Wendy D.; Tankersley, Claude D.

    1994-05-01

    Stochastic methods are used to analyze two-dimensional steady groundwater flow subject to spatially variable recharge and transmissivity. Approximate partial differential equations are developed for the covariances and cross-covariances between the random head, transmissivity and recharge fields. Closed-form solutions of these equations are obtained using Fourier transform techniques. The resulting covariances and cross-covariances can be incorporated into a Bayesian conditioning procedure which provides optimal estimates of the recharge, transmissivity and head fields given available measurements of any or all of these random fields. Results show that head measurements contain valuable information for estimating the random recharge field. However, when recharge is treated as a spatially variable random field, the value of head measurements for estimating the transmissivity field can be reduced considerably. In a companion paper, the method is applied to a case study of the Upper Floridan Aquifer in NE Florida.

  3. Random Effects: Variance Is the Spice of Life.

    PubMed

    Jupiter, Daniel C

    Covariates in regression analyses allow us to understand how independent variables of interest impact our dependent outcome variable. Often, we consider fixed effects covariates (e.g., gender or diabetes status) for which we examine subjects at each value of the covariate. We examine both men and women and, within each gender, examine both diabetic and nondiabetic patients. Occasionally, however, we consider random effects covariates for which we do not examine subjects at every value. For example, we examine patients from only a sample of hospitals and, within each hospital, examine both diabetic and nondiabetic patients. The random sampling of hospitals is in contrast to the complete coverage of all genders. In this column I explore the differences in meaning and analysis when thinking about fixed and random effects variables. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  4. Rotation Periods and Photometric Amplitudes for Cool Stars with TESS

    NASA Astrophysics Data System (ADS)

    Andrews, Hannah; Dominguez, Zechariah; Johnson, Sara; Buzasi, Derek L.

    2018-06-01

    The original Kepler mission observed 200000 stars in the same field nearly continuously for over four years, generating an unparalleled set of stellar rotation curves and new insights into the correlation between rotation periods and photometric variability on the lower main sequence. The continuation of Kepler in the guise of K2 has allowed us to examine a stellar sample comparable in size to that observed with Kepler, but drawn from new stellar populations. However, K2 observed each field for at most three months, limiting the inferences that can be drawn, particularly for older, slower-rotating stars. The upcoming TESS spacecraft will provide light curves for perhaps two orders of magnitude more stars, but with time windows as short as 27 days. In this work, we resample Kepler light curves using the TESS observing window, and study what can be learned from high-precision light curves of such short lengths, and how to compare those results to what we have learned from Kepler.

  5. Visual search for emotional expressions: Effect of stimulus set on anger and happiness superiority.

    PubMed

    Savage, Ruth A; Becker, Stefanie I; Lipp, Ottmar V

    2016-01-01

    Prior reports of preferential detection of emotional expressions in visual search have yielded inconsistent results, even for face stimuli that avoid obvious expression-related perceptual confounds. The current study investigated inconsistent reports of anger and happiness superiority effects using face stimuli drawn from the same database. Experiment 1 excluded procedural differences as a potential factor, replicating a happiness superiority effect in a procedure that previously yielded an anger superiority effect. Experiments 2a and 2b confirmed that image colour or poser gender did not account for prior inconsistent findings. Experiments 3a and 3b identified stimulus set as the critical variable, revealing happiness or anger superiority effects for two partially overlapping sets of face stimuli. The current results highlight the critical role of stimulus selection for the observation of happiness or anger superiority effects in visual search even for face stimuli that avoid obvious expression related perceptual confounds and are drawn from a single database.

  6. Effects of time and sampling location on concentrations of β-hydroxybutyric acid in dairy cows.

    PubMed

    Mahrt, A; Burfeind, O; Heuwieser, W

    2014-01-01

    Two trials were conducted to examine factors potentially influencing the measurement of blood β-hydroxybutyric acid (BHBA) in dairy cows. The objective of the first trial was to study effects of sampling time on BHBA concentration in continuously fed dairy cows. Furthermore, we determined test characteristics of a single BHBA measurement at a random time of the day to diagnose subclinical ketosis considering commonly used cut-points (1.2 and 1.4 mmol/L). Finally, we set out to evaluate if test characteristics could be enhanced by repeating measurements after different time intervals. During 4 herd visits, a total of 128 cows (8 to 28 d in milk) fed 10 times daily were screened at 0900 h and preselected by BHBA concentration. Blood samples were drawn from the tail vessels and BHBA concentrations were measured using an electronic BHBA meter (Precision Xceed, Abbott Diabetes Care Ltd., Witney, UK). Cows with BHBA concentrations ≥0.8 mmol/L at this time were enrolled in the trial (n=92). Subsequent BHBA measurements took place every 3h for a total of 8 measurements during 24 h. The effect of sampling time on BHBA concentrations was tested in a repeated-measures ANOVA repeating sampling time. Sampling time did not affect BHBA concentrations in continuously fed dairy cows. Defining the average daily BHBA concentration calculated from the 8 measurements as the gold standard, a single measurement at a random time of the day to diagnose subclinical ketosis had a sensitivity of 0.90 or 0.89 at the 2 BHBA cut-points (1.2 and 1.4 mmol/L). Specificity was 0.88 or 0.90 using the same cut-points. Repeating measurements after different time intervals improved test characteristics only slightly. In the second experiment, we compared BHBA concentrations of samples drawn from 3 different blood sampling locations (tail vessels, jugular vein, and mammary vein) of 116 lactating dairy cows. Concentrations of BHBA differed in samples from the 3 sampling locations. Mean BHBA concentration was 0.3 mmol/L lower when measured in the mammary vein compared with the jugular vein and 0.4 mmol/L lower in the mammary vein compared with the tail vessels. We conclude that to measure BHBA, blood samples of continuously fed dairy cows can be drawn at any time of the day. A single measurement provides very good test characteristics for on-farm conditions. Blood samples for BHBA measurement should be drawn from the jugular vein or tail vessels; the mammary vein should not be used for this purpose. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  7. Sampling Strategies for Evaluating the Rate of Adventitious Transgene Presence in Non-Genetically Modified Crop Fields.

    PubMed

    Makowski, David; Bancal, Rémi; Bensadoun, Arnaud; Monod, Hervé; Messéan, Antoine

    2017-09-01

    According to E.U. regulations, the maximum allowable rate of adventitious transgene presence in non-genetically modified (GM) crops is 0.9%. We compared four sampling methods for the detection of transgenic material in agricultural non-GM maize fields: random sampling, stratified sampling, random sampling + ratio reweighting, random sampling + regression reweighting. Random sampling involves simply sampling maize grains from different locations selected at random from the field concerned. The stratified and reweighting sampling methods make use of an auxiliary variable corresponding to the output of a gene-flow model (a zero-inflated Poisson model) simulating cross-pollination as a function of wind speed, wind direction, and distance to the closest GM maize field. With the stratified sampling method, an auxiliary variable is used to define several strata with contrasting transgene presence rates, and grains are then sampled at random from each stratum. With the two methods involving reweighting, grains are first sampled at random from various locations within the field, and the observations are then reweighted according to the auxiliary variable. Data collected from three maize fields were used to compare the four sampling methods, and the results were used to determine the extent to which transgene presence rate estimation was improved by the use of stratified and reweighting sampling methods. We found that transgene rate estimates were more accurate and that substantially smaller samples could be used with sampling strategies based on an auxiliary variable derived from a gene-flow model. © 2017 Society for Risk Analysis.

  8. Random variable transformation for generalized stochastic radiative transfer in finite participating slab media

    NASA Astrophysics Data System (ADS)

    El-Wakil, S. A.; Sallah, M.; El-Hanbaly, A. M.

    2015-10-01

    The stochastic radiative transfer problem is studied in a participating planar finite continuously fluctuating medium. The problem is considered for specular- and diffusly-reflecting boundaries with linear anisotropic scattering. Random variable transformation (RVT) technique is used to get the complete average for the solution functions, that are represented by the probability-density function (PDF) of the solution process. In the RVT algorithm, a simple integral transformation to the input stochastic process (the extinction function of the medium) is applied. This linear transformation enables us to rewrite the stochastic transport equations in terms of the optical random variable (x) and the optical random thickness (L). Then the transport equation is solved deterministically to get a closed form for the solution as a function of x and L. So, the solution is used to obtain the PDF of the solution functions applying the RVT technique among the input random variable (L) and the output process (the solution functions). The obtained averages of the solution functions are used to get the complete analytical averages for some interesting physical quantities, namely, reflectivity and transmissivity at the medium boundaries. In terms of the average reflectivity and transmissivity, the average of the partial heat fluxes for the generalized problem with internal source of radiation are obtained and represented graphically.

  9. Alcohol Use and Sexual Risk Behaviors in a Migrant Worker Community.

    PubMed

    McCoy, H Virginia; Shehadeh, Nancy; Rubens, Muni

    2016-06-01

    There are not many studies exploring the association between alcohol use and risky sexual behaviors among migrant workers. This study analyzed how changes in alcohol use was associated with changes in risky sexual behavior and psychosocial variables. Data for this study was drawn from an HIV risk reduction project. Repeated measures ANOVA and Linear mixed model statistical method was conducted to find changes and association between alcohol use, sexual risk and psychosocial variables over time. The sample (n = 203) was composed of African Americans (33.0 %) and Hispanics (77.0 %) men. Both groups, over time, showed reduction in sexual risk in accordance with reduction in alcohol use. Changes in alcohol use and psychosocial variables showed significant association with sexual risk changes over time. Psychological strategies like building social support should be considered for HIV risk reduction intervention directed towards high alcohol consuming migrant workers.

  10. Locomotion of Amorphous Surface Robots

    NASA Technical Reports Server (NTRS)

    Bradley, Arthur T. (Inventor)

    2018-01-01

    An amorphous robot includes a compartmented bladder containing fluid, a valve assembly, and an outer layer encapsulating the bladder and valve assembly. The valve assembly draws fluid from a compartment(s) and discharges the drawn fluid into a designated compartment to displace the designated compartment with respect to the surface. Another embodiment includes elements each having a variable property, an outer layer that encapsulates the elements, and a control unit. The control unit energizes a designated element to change its variable property, thereby moving the designated element. The elements may be electromagnetic spheres with a variable polarity or shape memory polymers with changing shape and/or size. Yet another embodiment includes an elongated flexible tube filled with ferrofluid, a moveable electromagnet, an actuator, and a control unit. The control unit energizes the electromagnet and moves the electromagnet via the actuator to magnetize the ferrofluid and lengthen the flexible tube.

  11. Locomotion of Amorphous Surface Robots

    NASA Technical Reports Server (NTRS)

    Bradley, Arthur T. (Inventor)

    2016-01-01

    An amorphous robot includes a compartmented bladder containing fluid, a valve assembly, and an outer layer encapsulating the bladder and valve assembly. The valve assembly draws fluid from a compartment(s) and discharges the drawn fluid into a designated compartment to displace the designated compartment with respect to the surface. Another embodiment includes elements each having a variable property, an outer layer that encapsulates the elements, and a control unit. The control unit energizes a designated element to change its variable property, thereby moving the designated element. The elements may be electromagnetic spheres with a variable polarity or shape memory polymers with changing shape and/or size. Yet another embodiment includes an elongated flexible tube filled with ferrofluid, a moveable electromagnet, an actuator, and a control unit. The control unit energizes the electromagnet and moves the electromagnet via the actuator to magnetize the ferrofluid and lengthen the flexible tube.

  12. Locomotion of Amorphous Surface Robots

    NASA Technical Reports Server (NTRS)

    Bradley, Arthur T. (Inventor)

    2014-01-01

    An amorphous robot includes a compartmented bladder containing fluid, a valve assembly, and an outer layer encapsulating the bladder and valve assembly. The valve assembly draws fluid from a compartment(s) and discharges the drawn fluid into a designated compartment to displace the designated compartment with respect to the surface. Another embodiment includes elements each having a variable property, an outer layer that encapsulates the elements, and a control unit. The control unit energizes a designated element to change its variable property, thereby moving the designated element. The elements may be electromagnetic spheres with a variable polarity or shape memory polymers with changing shape and/or size. Yet another embodiment includes an elongated flexible tube filled with ferrofluid, a moveable electromagnet, an actuator, and a control unit. The control unit energizes the electromagnet and moves the electromagnet via the actuator to magnetize the ferrofluid and lengthen the flexible tube.

  13. Exploring the Correlation Between Nontraditional Variables and Student Success: A Longitudinal Study.

    PubMed

    Strickland, Haley Perkins; Cheshire, Michelle Haney

    2017-06-01

    The purpose of this project was to determine whether a correlation exists between the traditional admission criteria of grade point averages with the potential admission criteria of emotional intelligence (EI) scores or critical thinking (CT) scores to predict upper division student outcomes. A quantitative, longitudinal design was selected to examine the identified variables to predict undergraduate student success. The recruiting sample included a convenience sample drawn from 112 junior-level undergraduate nursing students beginning their first of a five-semester nursing program. EI and HESI ® CT scores did not significantly correlate with main analysis variables. Although EI and CT scores were not significant in this study, it remains vital to incorporate EI and CT activities throughout the curriculum to develop students' ability to think like a nurse and, therefore, be successful in nursing practice. [J Nurs Educ. 2017;56(6):351-355.]. Copyright 2017, SLACK Incorporated.

  14. Image discrimination models predict detection in fixed but not random noise

    NASA Technical Reports Server (NTRS)

    Ahumada, A. J. Jr; Beard, B. L.; Watson, A. B. (Principal Investigator)

    1997-01-01

    By means of a two-interval forced-choice procedure, contrast detection thresholds for an aircraft positioned on a simulated airport runway scene were measured with fixed and random white-noise masks. The term fixed noise refers to a constant, or unchanging, noise pattern for each stimulus presentation. The random noise was either the same or different in the two intervals. Contrary to simple image discrimination model predictions, the same random noise condition produced greater masking than the fixed noise. This suggests that observers seem unable to hold a new noisy image for comparison. Also, performance appeared limited by internal process variability rather than by external noise variability, since similar masking was obtained for both random noise types.

  15. Insight among people with severe mental illness, co-occurring PTSD and elevated psychotic symptoms: Correlates and relationship to treatment participation.

    PubMed

    Yanos, Philip T; Vayshenker, Beth; Pleskach, Pavel; Mueser, Kim T

    2016-07-01

    There is a dearth of research on what factors are predictive of insight among people with severe mental illness and co-occurring PTSD. Data were drawn from 146 participants with severe mental illness, co-occurring PTSD and elevated psychotic symptoms participating in a randomized controlled trial comparing two interventions for PTSD among people with severe mental illness. We examined the clinical and demographic correlates of insight at baseline, the relationship between baseline insight and treatment participation, the relationship between treatment participation and post-treatment insight, and the relationship between change in insight and change in other clinical variables. Impaired insight was relatively common, with roughly half the sample demonstrating mild or moderate impairment at baseline. Baseline insight was associated with fewer psychotic and disorganized symptoms, and greater emotional discomfort and PTSD knowledge, but was not associated with negative symptoms, PTSD symptoms, depression/anxiety, or treatment participation. Participation in PTSD treatment was associated with increased insight at post-treatment. Improved insight was associated with improvements in disorganization and negative symptoms, but not with knowledge of PTSD or positive symptoms. The findings suggest that engagement in treatment that includes educating people about PTSD may lead to improvements in insight and related improvements in other psychiatric symptoms. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Prevalence and occupational predictors of psychological distress in the offshore petroleum industry: a prospective study.

    PubMed

    Nielsen, Morten Birkeland; Tvedt, Sturle Danielsen; Matthiesen, Stig Berge

    2013-11-01

    This study investigates the prevalence of psychological distress and stressors in the work environment as prospective predictors of distress, among employees in the offshore petroleum industry. Correlation and logistic regression analyses were employed to examine longitudinal relationships between stressors and distress in a randomly drawn sample of 741 employees from the Norwegian petroleum offshore industry. Time lag between baseline and follow-up was 6 months. Work environment stressors included safety factors, leadership, and job characteristics. The prevalence of psychological distress was 9 % at baseline and 8 % at follow-up. All investigated work environment factors correlated with subsequent distress. In bivariate logistic regression analyses, caseness of distress was predicted by baseline distress, near miss accidents, risk perception, poor safety climate, tyrannical leadership, laissez-faire leadership, job demands, and workplace bullying. After adjustment for baseline distress, control variables, and other predictors, laissez-faire leadership (OR = 1.69; 95 % CI: 1.12-2.54) and exposure to bullying (OR = 1.49; 95 % CI: 1.07-2.10) emerged as the most robust predictors of subsequent distress. The findings show that the prevalence of psychological distress is lower among offshore employees than in the general population. Although offshore workers operate in a physically challenging context, their mental health is mainly influenced by stressors in the psychosocial work environment. This highlights the importance of developing and implementing psychosocial safety interventions within the offshore industry.

  17. RESEARCH MISCONDUCT POLICIES OF SCIENTIFIC JOURNALS

    PubMed Central

    RESNIK, DAVID B.; PEDDADA, SHYAMAL; BRUNSON, WINNON

    2014-01-01

    The purpose of this study was to gather information on the misconduct policies of scientific journals. We contacted editors from a random sample of 399 journals drawn from the ISI Web of Knowledge database. We received 197 responses (49.4% response rate): 54.8% had a policy, and 47.7% had a formal (written) policy; 28.9% had a policy that only outlined procedures for handling misconduct, 15.7% had a policy that only defined misconduct, 10.2% had a policy that included both a definition and procedures; 26.9% of journals had a policy that was generated by the publisher, 13.2% had a policy that was generated by the journal, and 14.7% had a policy that was generated by another source, such as a professional association. We analyzed the relationship between having a policy and impact factor, field of science, publishing house, and nationality. Impact factor was the only variable with a statistically significant association with having a policy. Impact factor was slightly positively associated with whether or not the publisher had a policy, with an odds ratio of 1.49 (P < .0004) per 10 units increase in the impact factor, with a 95% confidence interval (1.20, 1.88). Our research indicates that more than half of scientific journals have developed misconduct policies, but that most of these policies do not define research misconduct and most of these policies were not generated by the journal. PMID:19757231

  18. Variable interpretation of ultrasonograms may contribute to variation in the reported incidence of white matter damage between newborn intensive care units in New Zealand

    PubMed Central

    Harris, D L; Bloomfield, F H; Teele, R L; Harding, J E

    2006-01-01

    Background The incidence of cerebral white matter damage reported to the Australian and New Zealand Neonatal Network (ANZNN) varies between neonatal intensive care units (NICUs). Hypothesis Differences in the capture, storage, and interpretation of the cerebral ultrasound scans could account for some of this variation. Methods A total of 255 infants of birth weight <1500 g and gestation <32 weeks born between 1997 and 2002 and drawn equally from each of the six NICUs in New Zealand were randomly selected from the ANZNN database. Half had early cerebral ultrasound scans previously reported to ANZNN as normal, and half had scans reported as abnormal. The original scans were copied, anonymised, and independently read by a panel of three experts using a standardised method of reviewing and reporting. Results There was considerable variation between NICUs in methods of image capture, quality, and completeness of the scans. There was only moderate agreement between the reviewers' reports and the original reports to the ANZNN (κ 0.45–0.51) and between the reviewers (κ 0.54–0.64). The reviewers reported three to six times more white matter damage than had been reported to the ANZNN. Conclusion Some of the reported variation in white matter damage between NICUs may be due to differences in capture and interpretation of cerebral ultrasound scans. PMID:16159954

  19. Statistical microeconomics and commodity prices: theory and empirical results.

    PubMed

    Baaquie, Belal E

    2016-01-13

    A review is made of the statistical generalization of microeconomics by Baaquie (Baaquie 2013 Phys. A 392, 4400-4416. (doi:10.1016/j.physa.2013.05.008)), where the market price of every traded commodity, at each instant of time, is considered to be an independent random variable. The dynamics of commodity market prices is given by the unequal time correlation function and is modelled by the Feynman path integral based on an action functional. The correlation functions of the model are defined using the path integral. The existence of the action functional for commodity prices that was postulated to exist in Baaquie (Baaquie 2013 Phys. A 392, 4400-4416. (doi:10.1016/j.physa.2013.05.008)) has been empirically ascertained in Baaquie et al. (Baaquie et al. 2015 Phys. A 428, 19-37. (doi:10.1016/j.physa.2015.02.030)). The model's action functionals for different commodities has been empirically determined and calibrated using the unequal time correlation functions of the market commodity prices using a perturbation expansion (Baaquie et al. 2015 Phys. A 428, 19-37. (doi:10.1016/j.physa.2015.02.030)). Nine commodities drawn from the energy, metal and grain sectors are empirically studied and their auto-correlation for up to 300 days is described by the model to an accuracy of R(2)>0.90-using only six parameters. © 2015 The Author(s).

  20. "Congratulations, you have been randomized into the control group!(?)": issues to consider when recruiting schools for matched-pair randomized control trials of prevention programs.

    PubMed

    Ji, Peter; DuBois, David L; Flay, Brian R; Brechling, Vanessa

    2008-03-01

    Recruiting schools into a matched-pair randomized control trial (MP-RCT) to evaluate the efficacy of a school-level prevention program presents challenges for researchers. We considered which of 2 procedures would be most effective for recruiting schools into the study and assigning them to conditions. In 1 procedure (recruit and match/randomize), we would recruit schools and match them prior to randomization, and in the other (match/randomize and recruitment), we would match schools and randomize them prior to recruitment. We considered how each procedure impacted the randomization process and our ability to recruit schools into the study. After implementing the selected procedure, the equivalence of both treatment and control group schools and the participating and nonparticipating schools on school demographic variables was evaluated. We decided on the recruit and match/randomize procedure because we thought it would provide the opportunity to build rapport with the schools and prepare them for the randomization process, thereby increasing the likelihood that they would accept their randomly assigned conditions. Neither the treatment and control group schools nor the participating and nonparticipating schools exhibited statistically significant differences from each other on any of the school demographic variables. Recruitment of schools prior to matching and randomization in an MP-RCT may facilitate the recruitment of schools and thus enhance both the statistical power and the representativeness of study findings. Future research would benefit from the consideration of a broader range of variables (eg, readiness to implement a comprehensive prevention program) both in matching schools and in evaluating their representativeness to nonparticipating schools.

  1. Random effects coefficient of determination for mixed and meta-analysis models.

    PubMed

    Demidenko, Eugene; Sargent, James; Onega, Tracy

    2012-01-01

    The key feature of a mixed model is the presence of random effects. We have developed a coefficient, called the random effects coefficient of determination, [Formula: see text], that estimates the proportion of the conditional variance of the dependent variable explained by random effects. This coefficient takes values from 0 to 1 and indicates how strong the random effects are. The difference from the earlier suggested fixed effects coefficient of determination is emphasized. If [Formula: see text] is close to 0, there is weak support for random effects in the model because the reduction of the variance of the dependent variable due to random effects is small; consequently, random effects may be ignored and the model simplifies to standard linear regression. The value of [Formula: see text] apart from 0 indicates the evidence of the variance reduction in support of the mixed model. If random effects coefficient of determination is close to 1 the variance of random effects is very large and random effects turn into free fixed effects-the model can be estimated using the dummy variable approach. We derive explicit formulas for [Formula: see text] in three special cases: the random intercept model, the growth curve model, and meta-analysis model. Theoretical results are illustrated with three mixed model examples: (1) travel time to the nearest cancer center for women with breast cancer in the U.S., (2) cumulative time watching alcohol related scenes in movies among young U.S. teens, as a risk factor for early drinking onset, and (3) the classic example of the meta-analysis model for combination of 13 studies on tuberculosis vaccine.

  2. Collision Models for Particle Orbit Code on SSX

    NASA Astrophysics Data System (ADS)

    Fisher, M. W.; Dandurand, D.; Gray, T.; Brown, M. R.; Lukin, V. S.

    2011-10-01

    Coulomb collision models are being developed and incorporated into the Hamiltonian particle pushing code (PPC) for applications to the Swarthmore Spheromak eXperiment (SSX). A Monte Carlo model based on that of Takizuka and Abe [JCP 25, 205 (1977)] performs binary collisions between test particles and thermal plasma field particles randomly drawn from a stationary Maxwellian distribution. A field-based electrostatic fluctuation model scatters particles from a spatially uniform random distribution of positive and negative spherical potentials generated throughout the plasma volume. The number, radii, and amplitude of these potentials are chosen to mimic the correct particle diffusion statistics without the use of random particle draws or collision frequencies. An electromagnetic fluctuating field model will be presented, if available. These numerical collision models will be benchmarked against known analytical solutions, including beam diffusion rates and Spitzer resistivity, as well as each other. The resulting collisional particle orbit models will be used to simulate particle collection with electrostatic probes in the SSX wind tunnel, as well as particle confinement in typical SSX fields. This work has been supported by US DOE, NSF and ONR.

  3. Complex growing networks with intrinsic vertex fitness

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

    Bedogne, C.; Rodgers, G. J.

    2006-10-15

    One of the major questions in complex network research is to identify the range of mechanisms by which a complex network can self organize into a scale-free state. In this paper we investigate the interplay between a fitness linking mechanism and both random and preferential attachment. In our models, each vertex is assigned a fitness x, drawn from a probability distribution {rho}(x). In Model A, at each time step a vertex is added and joined to an existing vertex, selected at random, with probability p and an edge is introduced between vertices with fitnesses x and y, with a ratemore » f(x,y), with probability 1-p. Model B differs from Model A in that, with probability p, edges are added with preferential attachment rather than randomly. The analysis of Model A shows that, for every fixed fitness x, the network's degree distribution decays exponentially. In Model B we recover instead a power-law degree distribution whose exponent depends only on p, and we show how this result can be generalized. The properties of a number of particular networks are examined.« less

  4. Random vectors and spatial analysis by geostatistics for geotechnical applications

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

    Young, D.S.

    1987-08-01

    Geostatistics is extended to the spatial analysis of vector variables by defining the estimation variance and vector variogram in terms of the magnitude of difference vectors. Many random variables in geotechnology are in vectorial terms rather than scalars, and its structural analysis requires those sample variable interpolations to construct and characterize structural models. A better local estimator will result in greater quality of input models; geostatistics can provide such estimators; kriging estimators. The efficiency of geostatistics for vector variables is demonstrated in a case study of rock joint orientations in geological formations. The positive cross-validation encourages application of geostatistics tomore » spatial analysis of random vectors in geoscience as well as various geotechnical fields including optimum site characterization, rock mechanics for mining and civil structures, cavability analysis of block cavings, petroleum engineering, and hydrologic and hydraulic modelings.« less

  5. The effect of sex education on adolescents' use of condoms: applying the Solomon four-group design.

    PubMed

    Kvalem, I L; Sundet, J M; Rivø, K I; Eilertsen, D A; Bakketeig, L S

    1996-02-01

    A school-based sex education program was developed in order to prevent sexually transmitted diseases and unwanted pregnancies. A Solomon four-group design, with random assignment to the different conditions, was used to evaluate an intervention based on cognitive social learning theory and social influence theory. The main goal of the intervention was to increase use of condoms. A stratified sample of 124 classes (2,411 students) was drawn at random from all the upper secondary schools (high schools/colleges) in one county in Norway. The results indicate a consistent interaction between pretest and intervention, which seems to have an effect on condom use. Pretest or intervention alone did not contribute to this effect. The interaction effect appeared among the students with few sexual partners. Several possible explanations to the observed interaction effect and the implication for future interventions are discussed.

  6. Extreme values and fat tails of multifractal fluctuations

    NASA Astrophysics Data System (ADS)

    Muzy, J. F.; Bacry, E.; Kozhemyak, A.

    2006-06-01

    In this paper we discuss the problem of the estimation of extreme event occurrence probability for data drawn from some multifractal process. We also study the heavy (power-law) tail behavior of probability density function associated with such data. We show that because of strong correlations, the standard extreme value approach is not valid and classical tail exponent estimators should be interpreted cautiously. Extreme statistics associated with multifractal random processes turn out to be characterized by non-self-averaging properties. Our considerations rely upon some analogy between random multiplicative cascades and the physics of disordered systems and also on recent mathematical results about the so-called multifractal formalism. Applied to financial time series, our findings allow us to propose an unified framework that accounts for the observed multiscaling properties of return fluctuations, the volatility clustering phenomenon and the observed “inverse cubic law” of the return pdf tails.

  7. Adaptive Markov Random Fields for Example-Based Super-resolution of Faces

    NASA Astrophysics Data System (ADS)

    Stephenson, Todd A.; Chen, Tsuhan

    2006-12-01

    Image enhancement of low-resolution images can be done through methods such as interpolation, super-resolution using multiple video frames, and example-based super-resolution. Example-based super-resolution, in particular, is suited to images that have a strong prior (for those frameworks that work on only a single image, it is more like image restoration than traditional, multiframe super-resolution). For example, hallucination and Markov random field (MRF) methods use examples drawn from the same domain as the image being enhanced to determine what the missing high-frequency information is likely to be. We propose to use even stronger prior information by extending MRF-based super-resolution to use adaptive observation and transition functions, that is, to make these functions region-dependent. We show with face images how we can adapt the modeling for each image patch so as to improve the resolution.

  8. The Internet and health information: differences in pet owners based on age, gender, and education.

    PubMed

    Kogan, Lori R; Schoenfeld-Tacher, Regina; Viera, Ann R

    2012-07-01

    The research assessed the attitudes and behaviors of pet owners pertaining to online search behavior for pet health information. A survey was conducted with a random sample of pet owners drawn from two US metropolitan areas and surrounding cities. Participating clinics were chosen randomly, and each participating clinic was asked to distribute 100 surveys to their clients until all surveys were disbursed. Although some perceptions and behaviors surrounding the use of the Internet for pet health information differ based on gender, age, or education level of pet owners, there are many aspects in which there are no differences based on these demographics. Results of the study suggest that closer examination of the common perception that gender, age, or education level has an effect on Internet behavior as it relates to veterinary medicine is required. Recommendations are made pertaining to the growing presence of the Internet and its impact on veterinary medicine.

  9. Chandra reveals a black hole X-ray binary within the ultraluminous supernova remnant MF 16

    NASA Astrophysics Data System (ADS)

    Roberts, T. P.; Colbert, E. J. M.

    2003-06-01

    We present evidence, based on Chandra ACIS-S observations of the nearby spiral galaxy NGC 6946, that the extraordinary X-ray luminosity of the MF 16 supernova remnant actually arises in a black hole X-ray binary. This conclusion is drawn from the point-like nature of the X-ray source, its X-ray spectrum closely resembling the spectrum of other ultraluminous X-ray sources thought to be black hole X-ray binary systems, and the detection of rapid hard X-ray variability from the source. We briefly discuss the nature of the hard X-ray variability, and the origin of the extreme radio and optical luminosity of MF 16 in light of this identification.

  10. WiseView: Visualizing motion and variability of faint WISE sources

    NASA Astrophysics Data System (ADS)

    Caselden, Dan; Westin, Paul, III; Meisner, Aaron; Kuchner, Marc; Colin, Guillaume

    2018-06-01

    WiseView renders image blinks of Wide-field Infrared Survey Explorer (WISE) coadds spanning a multi-year time baseline in a browser. The software allows for easy visual identification of motion and variability for sources far beyond the single-frame detection limit, a key threshold not surmounted by many studies. WiseView transparently gathers small image cutouts drawn from many terabytes of unWISE coadds, facilitating access to this large and unique dataset. Users need only input the coordinates of interest and can interactively tune parameters including the image stretch, colormap and blink rate. WiseView was developed in the context of the Backyard Worlds: Planet 9 citizen science project, and has enabled hundreds of brown dwarf candidate discoveries by citizen scientists and professional astronomers.

  11. Modeling Randomness in Judging Rating Scales with a Random-Effects Rating Scale Model

    ERIC Educational Resources Information Center

    Wang, Wen-Chung; Wilson, Mark; Shih, Ching-Lin

    2006-01-01

    This study presents the random-effects rating scale model (RE-RSM) which takes into account randomness in the thresholds over persons by treating them as random-effects and adding a random variable for each threshold in the rating scale model (RSM) (Andrich, 1978). The RE-RSM turns out to be a special case of the multidimensional random…

  12. Randomized trial of intermittent or continuous amnioinfusion for variable decelerations.

    PubMed

    Rinehart, B K; Terrone, D A; Barrow, J H; Isler, C M; Barrilleaux, P S; Roberts, W E

    2000-10-01

    To determine whether continuous or intermittent bolus amnioinfusion is more effective in relieving variable decelerations. Patients with repetitive variable decelerations were randomized to an intermittent bolus or continuous amnioinfusion. The intermittent bolus infusion group received boluses of 500 mL of normal saline, each over 30 minutes, with boluses repeated if variable decelerations recurred. The continuous infusion group received a bolus infusion of 500 mL of normal saline over 30 minutes and then 3 mL per minute until delivery occurred. The ability of the amnioinfusion to abolish variable decelerations was analyzed, as were maternal demographic and pregnancy outcome variables. Power analysis indicated that 64 patients would be required. Thirty-five patients were randomized to intermittent infusion and 30 to continuous infusion. There were no differences between groups in terms of maternal demographics, gestational age, delivery mode, neonatal outcome, median time to resolution of variable decelerations, or the number of times variable decelerations recurred. The median volume infused in the intermittent infusion group (500 mL) was significantly less than that in the continuous infusion group (905 mL, P =.003). Intermittent bolus amnioinfusion is as effective as continuous infusion in relieving variable decelerations in labor. Further investigation is necessary to determine whether either of these techniques is associated with increased occurrence of rare complications such as cord prolapse or uterine rupture.

  13. An Analysis of Mimosa pudica Leaves Movement by Using LoggerPro Software

    NASA Astrophysics Data System (ADS)

    Sugito; Susilo; Handayani, L.; Marwoto, P.

    2016-08-01

    The unique phenomena of Mimosa pudica are the closing and opening movements of its leaves when they got a stimulus. By using certain software, these movements can be drawn into graphic that can be analysed. The LoggerPro provides facilities needed to analyse recorded videos of the plant's reaction to stimulus. Then, through the resulted graph, analysis of some variables can be carried out. The result showed that the plant's movement fits an equation of y = mx + c.

  14. Optical polarimetry and photometry of X-ray selected BL Lacertae objects

    NASA Technical Reports Server (NTRS)

    Jannuzi, Buell T.; Smith, Paul S.; Elston, Richard

    1993-01-01

    We present the data from 3 years of monitoring the optical polarization and apparent brightness of 37 X-ray-selected BL Lacertae objects. The monitored objects include a complete sample drawn from the Einstein Extended Medium Sensitivity Survey. We confirm the BL Lac identifications for 15 of these 22 objects. We include descriptions of the objects and samples in our monitoring program and of the existing complete samples of BL Lac objects, highly polarized quasars, optically violent variable quasars, and blazars.

  15. An Investigation into the Comparative Costs of Additive Manufacture vs. Machine from Solid for Aero Engine Parts

    DTIC Science & Technology

    2006-05-01

    welding power sources are not totally efficient at converting power drawn from the wall into heat energy used for the welding process . TIG sources are...Powder bed + Laser • Wire + Laser • Wire + Electron Beam • Wire + TIG Each system has its own unique attributes in terms of process variables...relative economics of producing a near net shape by Additive Manufacturing (AM) processes compared with traditional machine from solid processes (MFS

  16. Decision tree modeling using R.

    PubMed

    Zhang, Zhongheng

    2016-08-01

    In machine learning field, decision tree learner is powerful and easy to interpret. It employs recursive binary partitioning algorithm that splits the sample in partitioning variable with the strongest association with the response variable. The process continues until some stopping criteria are met. In the example I focus on conditional inference tree, which incorporates tree-structured regression models into conditional inference procedures. While growing a single tree is subject to small changes in the training data, random forests procedure is introduced to address this problem. The sources of diversity for random forests come from the random sampling and restricted set of input variables to be selected. Finally, I introduce R functions to perform model based recursive partitioning. This method incorporates recursive partitioning into conventional parametric model building.

  17. How resilient are ecosystems in adapting to climate variability

    NASA Astrophysics Data System (ADS)

    Savenije, Hubert H. G.

    2015-04-01

    The conclusion often drawn in the media is that ecosystems may perish as a result of climate change. Although climatic trends may indeed lead to shifts in ecosystem composition, the challenge to adjust to climatic variability - even if there is no trend - is larger, particularly in semi-arid or topical climates where climatic variability is large compared to temperate climates. How do ecosystems buffer for climatic variability? The most powerful mechanism is to invest in root zone storage capacity, so as to guarantee access to water and nutrients during period of drought. This investment comes at a cost of having less energy available to invest in growth or formation of fruits. Ecosystems are expected to create sufficient buffer to overcome critical periods of drought, but not more than is necessary to survive or reproduce. Based on this concept, a methodology has been developed to estimate ecosystem root zone storage capacity at local, regional and global scale. These estimates correspond well with estimates made by combining soil and ecosystem information, but are more accurate and more detailed. The methodology shows that ecosystems have intrinsic capacity to adjust to climatic variability and hence have a high resilience to both climatic variability and climatic trends.

  18. Simple techniques for improving deep neural network outcomes on commodity hardware

    NASA Astrophysics Data System (ADS)

    Colina, Nicholas Christopher A.; Perez, Carlos E.; Paraan, Francis N. C.

    2017-08-01

    We benchmark improvements in the performance of deep neural networks (DNN) on the MNIST data test upon imple-menting two simple modifications to the algorithm that have little overhead computational cost. First is GPU parallelization on a commodity graphics card, and second is initializing the DNN with random orthogonal weight matrices prior to optimization. Eigenspectra analysis of the weight matrices reveal that the initially orthogonal matrices remain nearly orthogonal after training. The probability distributions from which these orthogonal matrices are drawn are also shown to significantly affect the performance of these deep neural networks.

  19. Interrater reliability of the DSM-III diagnoses in two Norwegian studies on psychiatric and super obese patients.

    PubMed

    Larsen, F; Vaglum, S

    1986-01-01

    Two Norwegian psychiatrists classified independently according to DSM-III, 45 patients drawn at random from two populations: one of psychiatric patients (N = 161) and one of super obese surgical patients (N = 71). They interviewed the patients and listened to each other's audio-taped interviews afterwards. In the total group, on axis I the overall agreement was 78 percent (kappa = 0.74). On axis II, the overall agreement was 81 percent (kappa = 0.68). The study shows that by using the DSM-III, two Norwegian psychiatrists obtained good diagnostic reliability.

  20. Mesoscopic coherence in light scattering from cold, optically dense and disordered atomic systems

    NASA Astrophysics Data System (ADS)

    Kupriyanov, D. V.; Sokolov, I. M.; Havey, M. D.

    2017-02-01

    Coherent effects manifested in light scattering from cold, optically dense and disordered atomic systems are reviewed from a primarily theoretical point of view. Development of the basic theoretical tools is then elaborated through several physical atomic physics based processes which have been at least partly explored experimentally. These include illustrations drawn from the coherent backscattering effect, random lasing in atomic gases, quantum memories and light-atoms interface assisted by the light trapping mechanism. Current understanding and challenges associated with the transition to high atomic densities and cooperativity in the scattering process are also discussed in some detail.

  1. The Relative Risk of Divorce in Parents of Children With Developmental Disabilities: Impacts of Lifelong Parenting.

    PubMed

    Namkung, Eun Ha; Song, Jieun; Greenberg, Jan S; Mailick, Marsha R; Floyd, Frank J

    2015-11-01

    We prospectively examined the risk of divorce in 190 parents of children with developmental disabilities compared to 7,251 parents of children without disabilities based on a random sample drawn from the community and followed longitudinally for over 50 years. A significant interaction between the parental group status and number of children was found: In the comparison group, having a larger number of children was related to an increased risk of divorce, whereas the number of children did not increase divorce risk among parents of children with developmental disabilities.

  2. The Relative Risk of Divorce in Parents of Children with Developmental Disabilities: Impacts of Lifelong Parenting

    PubMed Central

    Song, Jieun; Greenberg, Jan S.; Mailick, Marsha R.; Floyd, Frank J.

    2015-01-01

    We examined prospectively the risk of divorce in 190 parents of children with developmental disabilities compared to 7,251 parents of children without disabilities based on a random sample drawn from the community and followed longitudinally for over 50 years. A significant interaction between the parental group status and number of children was found: In the comparison group, having a larger number of children was related to an increased risk of divorce, whereas the number of children did not increase divorce risk among parents of children with developmental disabilities. PMID:26505872

  3. The male-taller norm: Lack of evidence from a developing country.

    PubMed

    Sohn, K

    2015-08-01

    In general, women prefer men taller than themselves; this is referred to as the male-taller norm. However, since women are shorter than men on average, it is difficult to determine whether the fact that married women are on average shorter than their husbands results from the norm or is a simple artifact generated by the shorter stature of women. This study addresses the question by comparing the rate of adherence to the male-taller norm between actual mating and hypothetical random mating. A total of 7954 actually married couples are drawn from the last follow-up of the Indonesian Family Life Survey, a nationally representative survey. Their heights were measured by trained nurses. About 10,000 individuals are randomly sampled from the actual couples and randomly matched. An alternative random mating of about 100,000 couples is also performed, taking into account an age difference of 5 years within a couple. The rate of adherence to the male-taller norm is 93.4% for actual couples and 88.8% for random couples. The difference between the two figures is statistically significant, but it is emphasized that it is very small. The alternative random mating produces a rate of 91.4%. The male-taller norm exists in Indonesia, but only in a statistical sense. The small difference suggests that the norm is mostly explained by the fact that women are shorter than men on average. Copyright © 2015 Elsevier GmbH. All rights reserved.

  4. Reliability analysis of structures under periodic proof tests in service

    NASA Technical Reports Server (NTRS)

    Yang, J.-N.

    1976-01-01

    A reliability analysis of structures subjected to random service loads and periodic proof tests treats gust loads and maneuver loads as random processes. Crack initiation, crack propagation, and strength degradation are treated as the fatigue process. The time to fatigue crack initiation and ultimate strength are random variables. Residual strength decreases during crack propagation, so that failure rate increases with time. When a structure fails under periodic proof testing, a new structure is built and proof-tested. The probability of structural failure in service is derived from treatment of all the random variables, strength degradations, service loads, proof tests, and the renewal of failed structures. Some numerical examples are worked out.

  5. Smooth conditional distribution function and quantiles under random censorship.

    PubMed

    Leconte, Eve; Poiraud-Casanova, Sandrine; Thomas-Agnan, Christine

    2002-09-01

    We consider a nonparametric random design regression model in which the response variable is possibly right censored. The aim of this paper is to estimate the conditional distribution function and the conditional alpha-quantile of the response variable. We restrict attention to the case where the response variable as well as the explanatory variable are unidimensional and continuous. We propose and discuss two classes of estimators which are smooth with respect to the response variable as well as to the covariate. Some simulations demonstrate that the new methods have better mean square error performances than the generalized Kaplan-Meier estimator introduced by Beran (1981) and considered in the literature by Dabrowska (1989, 1992) and Gonzalez-Manteiga and Cadarso-Suarez (1994).

  6. AUTOCLASSIFICATION OF THE VARIABLE 3XMM SOURCES USING THE RANDOM FOREST MACHINE LEARNING ALGORITHM

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

    Farrell, Sean A.; Murphy, Tara; Lo, Kitty K., E-mail: s.farrell@physics.usyd.edu.au

    In the current era of large surveys and massive data sets, autoclassification of astrophysical sources using intelligent algorithms is becoming increasingly important. In this paper we present the catalog of variable sources in the Third XMM-Newton Serendipitous Source catalog (3XMM) autoclassified using the Random Forest machine learning algorithm. We used a sample of manually classified variable sources from the second data release of the XMM-Newton catalogs (2XMMi-DR2) to train the classifier, obtaining an accuracy of ∼92%. We also evaluated the effectiveness of identifying spurious detections using a sample of spurious sources, achieving an accuracy of ∼95%. Manual investigation of amore » random sample of classified sources confirmed these accuracy levels and showed that the Random Forest machine learning algorithm is highly effective at automatically classifying 3XMM sources. Here we present the catalog of classified 3XMM variable sources. We also present three previously unidentified unusual sources that were flagged as outlier sources by the algorithm: a new candidate supergiant fast X-ray transient, a 400 s X-ray pulsar, and an eclipsing 5 hr binary system coincident with a known Cepheid.« less

  7. A Probabilistic Design Method Applied to Smart Composite Structures

    NASA Technical Reports Server (NTRS)

    Shiao, Michael C.; Chamis, Christos C.

    1995-01-01

    A probabilistic design method is described and demonstrated using a smart composite wing. Probabilistic structural design incorporates naturally occurring uncertainties including those in constituent (fiber/matrix) material properties, fabrication variables, structure geometry and control-related parameters. Probabilistic sensitivity factors are computed to identify those parameters that have a great influence on a specific structural reliability. Two performance criteria are used to demonstrate this design methodology. The first criterion requires that the actuated angle at the wing tip be bounded by upper and lower limits at a specified reliability. The second criterion requires that the probability of ply damage due to random impact load be smaller than an assigned value. When the relationship between reliability improvement and the sensitivity factors is assessed, the results show that a reduction in the scatter of the random variable with the largest sensitivity factor (absolute value) provides the lowest failure probability. An increase in the mean of the random variable with a negative sensitivity factor will reduce the failure probability. Therefore, the design can be improved by controlling or selecting distribution parameters associated with random variables. This can be implemented during the manufacturing process to obtain maximum benefit with minimum alterations.

  8. Methods of pushing during vaginal delivery and pelvic floor and perineal outcomes: a review.

    PubMed

    de Tayrac, Renaud; Letouzey, Vincent

    2016-12-01

    Over the past 20 years, several randomized studies have compared Valsalva and spontaneous pushing techniques during vaginal delivery. This review summarizes current medical knowledge concerning their maternal and fetal consequences, focusing on pelvic and perineal outcomes. We selected nine randomized controlled trials comparing Valsalva and spontaneous pushing, and a secondary analysis of a randomized controlled trial comparing different methods of perineal protection. Two trials showed that spontaneous pushing reduces the risk of perineal tears, but no firm conclusions can be drawn given the heterogeneity and inconsistent results of these studies. Conflicting results have been reported regarding the duration of the second stage of labor. Pushing technique does not seem to affect episiotomy, instrumental delivery or cesarean rates. Maternal satisfaction seems to be better after spontaneous pushing. Spontaneous pushing appears to have no adverse effects on neonatal well being, and one study showed a significant improvement in prenatal fetal parameters during the expulsive phase. Valsalva and spontaneous pushing techniques currently appear comparable in terms of duration, pelvic floor, perineal, and neonatal outcomes. In the absence of strong evidence in favor of either technique, the decision should be guided by patient preference and the clinical situation. Additional, well-designed randomized controlled trials are required.

  9. Extended q -Gaussian and q -exponential distributions from gamma random variables

    NASA Astrophysics Data System (ADS)

    Budini, Adrián A.

    2015-05-01

    The family of q -Gaussian and q -exponential probability densities fit the statistical behavior of diverse complex self-similar nonequilibrium systems. These distributions, independently of the underlying dynamics, can rigorously be obtained by maximizing Tsallis "nonextensive" entropy under appropriate constraints, as well as from superstatistical models. In this paper we provide an alternative and complementary scheme for deriving these objects. We show that q -Gaussian and q -exponential random variables can always be expressed as a function of two statistically independent gamma random variables with the same scale parameter. Their shape index determines the complexity q parameter. This result also allows us to define an extended family of asymmetric q -Gaussian and modified q -exponential densities, which reduce to the standard ones when the shape parameters are the same. Furthermore, we demonstrate that a simple change of variables always allows relating any of these distributions with a beta stochastic variable. The extended distributions are applied in the statistical description of different complex dynamics such as log-return signals in financial markets and motion of point defects in a fluid flow.

  10. Factors related to severe untreated tooth decay in rural adolescents: a case-control study for public health planning.

    PubMed

    Skaret, E; Weinstein, P; Milgrom, P; Kaakko, T; Getz, T

    2004-01-01

    In this case-control study of rural adolescents we identified factors to discriminate those who have high levels of tooth decay and receive treatment from those with similar levels who receive no treatment. The sample was drawn from all 12-20-year-olds (n = 439) in a rural high school in Washington State, U.S. The criterion for being included was 5 or more decayed, missing or filled teeth. The questionnaire included structure, history, cognition and expectation variables based on a model by Grembowski, Andersen and Chen. No structural variable was related to the dependent variable. Two of 10 history variables were related: perceived poor own dental health and perceived poor mother's dental health. Four of eight cognition variables were also predictive: negative beliefs about the dentist, not planning to go to a dentist even if having severe problems, not being in any club or playing on a sports team and not having a best friend. No relationship was found for the expectation variable 'usual source of care'. These data are consistent with the hypothesis that untreated tooth decay is associated with avoidance of care and point to the importance of history and cognition variables in planning efforts to improve oral health of rural adolescents.

  11. Assessing the Habitat of Coccidioides posadasii, the Valley Fever Pathogen: A Study of Environmental Variables and Human Incidence Data in Arizona

    NASA Astrophysics Data System (ADS)

    Mann, Sarina N.

    Coccidioidomycosis, or Valley Fever, is an infectious disease caused by inhalation of soil-dwelling fungus Coccidioides posadasii spores in the Lower Sonoran Life Zone (LSLZ) in Arizona. In the context of climate change, the habitat of environmentally-mediated infectious diseases, such as Valley Fever, are expected to change. Connections have been drawn between climate and Valley Fever infection. The operational scale of the organism is still unknown. Here, we use climatic variables, including precipitation, soil moisture, and temperature. We use PRISM precipitation and temperature data, and Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) as a measure of soil moisture for the entire state of Arizona, divided into 126 primary care areas (PCA). These data are analyzed and regressed with Valley Fever incidence to determine the effects of climatic variability on disease distribution and timing. This study confirms that Valley Fever occurrence is clustered in the LSLZ. Seasonal Valley Fever outbreak was found to be variable year-to-year based on climatic variability. The inconclusive regression analyses indicate that the operational scale of Coccidioides is smaller than the PCA region. All variables are related to Valley Fever infection, but one variable was not found to hold more predictive power than others.

  12. Optimal allocation of testing resources for statistical simulations

    NASA Astrophysics Data System (ADS)

    Quintana, Carolina; Millwater, Harry R.; Singh, Gulshan; Golden, Patrick

    2015-07-01

    Statistical estimates from simulation involve uncertainty caused by the variability in the input random variables due to limited data. Allocating resources to obtain more experimental data of the input variables to better characterize their probability distributions can reduce the variance of statistical estimates. The methodology proposed determines the optimal number of additional experiments required to minimize the variance of the output moments given single or multiple constraints. The method uses multivariate t-distribution and Wishart distribution to generate realizations of the population mean and covariance of the input variables, respectively, given an amount of available data. This method handles independent and correlated random variables. A particle swarm method is used for the optimization. The optimal number of additional experiments per variable depends on the number and variance of the initial data, the influence of the variable in the output function and the cost of each additional experiment. The methodology is demonstrated using a fretting fatigue example.

  13. Evaluating physical habitat and water chemistry data from statewide stream monitoring programs to establish least-impacted conditions in Washington State

    USGS Publications Warehouse

    Wilmoth, Siri K.; Irvine, Kathryn M.; Larson, Chad

    2015-01-01

    Various GIS-generated land-use predictor variables, physical habitat metrics, and water chemistry variables from 75 reference streams and 351 randomly sampled sites throughout Washington State were evaluated for effectiveness at discriminating reference from random sites within level III ecoregions. A combination of multivariate clustering and ordination techniques were used. We describe average observed conditions for a subset of predictor variables as well as proposing statistical criteria for establishing reference conditions for stream habitat in Washington. Using these criteria, we determined whether any of the random sites met expectations for reference condition and whether any of the established reference sites failed to meet expectations for reference condition. Establishing these criteria will set a benchmark from which future data will be compared.

  14. Non-manipulation quantitative designs.

    PubMed

    Rumrill, Phillip D

    2004-01-01

    The article describes non-manipulation quantitative designs of two types, correlational and causal comparative studies. Both of these designs are characterized by the absence of random assignment of research participants to conditions or groups and non-manipulation of the independent variable. Without random selection or manipulation of the independent variable, no attempt is made to draw causal inferences regarding relationships between independent and dependent variables. Nonetheless, non-manipulation studies play an important role in rehabilitation research, as described in this article. Examples from the contemporary rehabilitation literature are included. Copyright 2004 IOS Press

  15. Morinda citrifolia (Noni) as an Anti-Inflammatory Treatment in Women with Primary Dysmenorrhoea: A Randomised Double-Blind Placebo-Controlled Trial.

    PubMed

    Fletcher, H M; Dawkins, J; Rattray, C; Wharfe, G; Reid, M; Gordon-Strachan, G

    2013-01-01

    Introduction. Noni (Morinda citrifolia) has been used for many years as an anti-inflammatory agent. We tested the efficacy of Noni in women with dysmenorrhea. Method. We did a prospective randomized double-blind placebo-controlled trial in 100 university students of 18 years and older over three menstrual cycles. Patients were invited to participate and randomly assigned to receive 400 mg Noni capsules or placebo. They were assessed for baseline demographic variables such as age, parity, and BMI. They were also assessed before and after treatment, for pain, menstrual blood loss, and laboratory variables: ESR, hemoglobin, and packed cell volume. Results. Of the 1027 women screened, 100 eligible women were randomized. Of the women completing the study, 42 women were randomized to Noni and 38 to placebo. There were no significant differences in any of the variables at randomization. There were also no significant differences in mean bleeding score or pain score at randomization. Both bleeding and pain scores gradually improved in both groups as the women were observed over three menstrual cycles; however, the improvement was not significantly different in the Noni group when compared to the controls. Conclusion. Noni did not show a reduction in menstrual pain or bleeding when compared to placebo.

  16. Morinda citrifolia (Noni) as an Anti-Inflammatory Treatment in Women with Primary Dysmenorrhoea: A Randomised Double-Blind Placebo-Controlled Trial

    PubMed Central

    Fletcher, H. M.; Dawkins, J.; Rattray, C.; Wharfe, G.; Reid, M.; Gordon-Strachan, G.

    2013-01-01

    Introduction. Noni (Morinda citrifolia) has been used for many years as an anti-inflammatory agent. We tested the efficacy of Noni in women with dysmenorrhea. Method. We did a prospective randomized double-blind placebo-controlled trial in 100 university students of 18 years and older over three menstrual cycles. Patients were invited to participate and randomly assigned to receive 400 mg Noni capsules or placebo. They were assessed for baseline demographic variables such as age, parity, and BMI. They were also assessed before and after treatment, for pain, menstrual blood loss, and laboratory variables: ESR, hemoglobin, and packed cell volume. Results. Of the 1027 women screened, 100 eligible women were randomized. Of the women completing the study, 42 women were randomized to Noni and 38 to placebo. There were no significant differences in any of the variables at randomization. There were also no significant differences in mean bleeding score or pain score at randomization. Both bleeding and pain scores gradually improved in both groups as the women were observed over three menstrual cycles; however, the improvement was not significantly different in the Noni group when compared to the controls. Conclusion. Noni did not show a reduction in menstrual pain or bleeding when compared to placebo. PMID:23431314

  17. K-Means Algorithm Performance Analysis With Determining The Value Of Starting Centroid With Random And KD-Tree Method

    NASA Astrophysics Data System (ADS)

    Sirait, Kamson; Tulus; Budhiarti Nababan, Erna

    2017-12-01

    Clustering methods that have high accuracy and time efficiency are necessary for the filtering process. One method that has been known and applied in clustering is K-Means Clustering. In its application, the determination of the begining value of the cluster center greatly affects the results of the K-Means algorithm. This research discusses the results of K-Means Clustering with starting centroid determination with a random and KD-Tree method. The initial determination of random centroid on the data set of 1000 student academic data to classify the potentially dropout has a sse value of 952972 for the quality variable and 232.48 for the GPA, whereas the initial centroid determination by KD-Tree has a sse value of 504302 for the quality variable and 214,37 for the GPA variable. The smaller sse values indicate that the result of K-Means Clustering with initial KD-Tree centroid selection have better accuracy than K-Means Clustering method with random initial centorid selection.

  18. Designing management strategies for carbon dioxide storage and utilization under uncertainty using inexact modelling

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Fan, Jie; Xu, Ye; Sun, Wei; Chen, Dong

    2017-06-01

    Effective application of carbon capture, utilization and storage (CCUS) systems could help to alleviate the influence of climate change by reducing carbon dioxide (CO2) emissions. The research objective of this study is to develop an equilibrium chance-constrained programming model with bi-random variables (ECCP model) for supporting the CCUS management system under random circumstances. The major advantage of the ECCP model is that it tackles random variables as bi-random variables with a normal distribution, where the mean values follow a normal distribution. This could avoid irrational assumptions and oversimplifications in the process of parameter design and enrich the theory of stochastic optimization. The ECCP model is solved by an equilibrium change-constrained programming algorithm, which provides convenience for decision makers to rank the solution set using the natural order of real numbers. The ECCP model is applied to a CCUS management problem, and the solutions could be useful in helping managers to design and generate rational CO2-allocation patterns under complexities and uncertainties.

  19. Log-normal distribution from a process that is not multiplicative but is additive.

    PubMed

    Mouri, Hideaki

    2013-10-01

    The central limit theorem ensures that a sum of random variables tends to a Gaussian distribution as their total number tends to infinity. However, for a class of positive random variables, we find that the sum tends faster to a log-normal distribution. Although the sum tends eventually to a Gaussian distribution, the distribution of the sum is always close to a log-normal distribution rather than to any Gaussian distribution if the summands are numerous enough. This is in contrast to the current consensus that any log-normal distribution is due to a product of random variables, i.e., a multiplicative process, or equivalently to nonlinearity of the system. In fact, the log-normal distribution is also observable for a sum, i.e., an additive process that is typical of linear systems. We show conditions for such a sum, an analytical example, and an application to random scalar fields such as those of turbulence.

  20. Variable density randomized stack of spirals (VDR-SoS) for compressive sensing MRI.

    PubMed

    Valvano, Giuseppe; Martini, Nicola; Landini, Luigi; Santarelli, Maria Filomena

    2016-07-01

    To develop a 3D sampling strategy based on a stack of variable density spirals for compressive sensing MRI. A random sampling pattern was obtained by rotating each spiral by a random angle and by delaying for few time steps the gradient waveforms of the different interleaves. A three-dimensional (3D) variable sampling density was obtained by designing different variable density spirals for each slice encoding. The proposed approach was tested with phantom simulations up to a five-fold undersampling factor. Fully sampled 3D dataset of a human knee, and of a human brain, were obtained from a healthy volunteer. The proposed approach was tested with off-line reconstructions of the knee dataset up to a four-fold acceleration and compared with other noncoherent trajectories. The proposed approach outperformed the standard stack of spirals for various undersampling factors. The level of coherence and the reconstruction quality of the proposed approach were similar to those of other trajectories that, however, require 3D gridding for the reconstruction. The variable density randomized stack of spirals (VDR-SoS) is an easily implementable trajectory that could represent a valid sampling strategy for 3D compressive sensing MRI. It guarantees low levels of coherence without requiring 3D gridding. Magn Reson Med 76:59-69, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  1. Large area substrate for surface enhanced Raman spectroscopy (SERS) using glass-drawing technique

    DOEpatents

    Ivanov, Ilia N; Simpson, John T

    2012-06-26

    A method of making a large area substrate comprises drawing a plurality of tubes to form a plurality of drawn tubes, and cutting the plurality of drawn tubes into cut drawn tubes. Each cut drawn tube has a first end and a second end along the longitudinal direction of the respective cut drawn tube. The cut drawn tubes collectively have a predetermined periodicity. The method of making a large area substrate also comprises forming a metal layer on the first ends of the cut drawn tubes to provide a large area substrate.

  2. Method of making large area conformable shape structures for detector/sensor applications using glass drawing technique and postprocessing

    DOEpatents

    Ivanov, Ilia N [Knoxville, TN; Simpson, John T [Clinton, IN

    2012-01-24

    A method of making a large area conformable shape structure comprises drawing a plurality of tubes to form a plurality of drawn tubes, and cutting the plurality of drawn tubes into cut drawn tubes of a predetermined shape. The cut drawn tubes have a first end and a second end along the longitudinal direction of the cut drawn tubes. The method further comprises conforming the first end of the cut drawn tubes into a predetermined curve to form the large area conformable shape structure, wherein the cut drawn tubes contain a material.

  3. Are great apes able to reason from multi-item samples to populations of food items?

    PubMed

    Eckert, Johanna; Rakoczy, Hannes; Call, Josep

    2017-10-01

    Inductive learning from limited observations is a cognitive capacity of fundamental importance. In humans, it is underwritten by our intuitive statistics, the ability to draw systematic inferences from populations to randomly drawn samples and vice versa. According to recent research in cognitive development, human intuitive statistics develops early in infancy. Recent work in comparative psychology has produced first evidence for analogous cognitive capacities in great apes who flexibly drew inferences from populations to samples. In the present study, we investigated whether great apes (Pongo abelii, Pan troglodytes, Pan paniscus, Gorilla gorilla) also draw inductive inferences in the opposite direction, from samples to populations. In two experiments, apes saw an experimenter randomly drawing one multi-item sample from each of two populations of food items. The populations differed in their proportion of preferred to neutral items (24:6 vs. 6:24) but apes saw only the distribution of food items in the samples that reflected the distribution of the respective populations (e.g., 4:1 vs. 1:4). Based on this observation they were then allowed to choose between the two populations. Results show that apes seemed to make inferences from samples to populations and thus chose the population from which the more favorable (4:1) sample was drawn in Experiment 1. In this experiment, the more attractive sample not only contained proportionally but also absolutely more preferred food items than the less attractive sample. Experiment 2, however, revealed that when absolute and relative frequencies were disentangled, apes performed at chance level. Whether these limitations in apes' performance reflect true limits of cognitive competence or merely performance limitations due to accessory task demands is still an open question. © 2017 Wiley Periodicals, Inc.

  4. Random Item IRT Models

    ERIC Educational Resources Information Center

    De Boeck, Paul

    2008-01-01

    It is common practice in IRT to consider items as fixed and persons as random. Both, continuous and categorical person parameters are most often random variables, whereas for items only continuous parameters are used and they are commonly of the fixed type, although exceptions occur. It is shown in the present article that random item parameters…

  5. Is the Non-Dipole Magnetic Field Random?

    NASA Technical Reports Server (NTRS)

    Walker, Andrew D.; Backus, George E.

    1996-01-01

    Statistical modelling of the Earth's magnetic field B has a long history. In particular, the spherical harmonic coefficients of scalar fields derived from B can be treated as Gaussian random variables. In this paper, we give examples of highly organized fields whose spherical harmonic coefficients pass tests for independent Gaussian random variables. The fact that coefficients at some depth may be usefully summarized as independent samples from a normal distribution need not imply that there really is some physical, random process at that depth. In fact, the field can be extremely structured and still be regarded for some purposes as random. In this paper, we examined the radial magnetic field B(sub r) produced by the core, but the results apply to any scalar field on the core-mantle boundary (CMB) which determines B outside the CMB.

  6. Association between proton pump inhibitors and hepatic encephalopathy

    PubMed Central

    Bian, Jin; Wang, Anqiang; Lin, Jianzhen; Wu, Liangcai; Huang, Hanchun; Wang, Shanshan; Yang, Xiaobo; Lu, Xin; Xu, Yiyao; Zhao, Haitao

    2017-01-01

    Abstract Background & aims: Several studies have shown that proton pump inhibitors (PPIs) use can increase the risk of developing hepatic encephalopathy (HE) in patients with liver dysfunction. However, no definite conclusion is drawn because of study design limitations. Therefore, we conducted a meta-analysis to explore the association between PPIs and HE. Methods: We searched PubMed, EMBASE, and the Cochrane Library from inception until November 2016. Data from the identified studies were combined using a random effects model, and odds ratios (ORs) were calculated. Results: Three case-control studies were included. Compared with nonusers, hepatic insufficiency patients receiving PPIs therapy had a significantly increased risk of developing HE (OR = 1.76, 95% CI: 1.15–2.69), with notable heterogeneity (I2 = 61.4%, P = .075) and publication bias. No relevance was found between PPIs and HE after using the trim and fill method (OR = 1.360, 95%CI: 0.909–2.035, P = .135). Conclusions: PPIs are associated with a higher risk of HE among patients with chronic and acute liver dysfunction. A final conclusion cannot be drawn because of the limited number of studies and a lack of prospective studies. PMID:28445288

  7. Are glucose levels, glucose variability and autonomic control influenced by inspiratory muscle exercise in patients with type 2 diabetes? Study protocol for a randomized controlled trial.

    PubMed

    Schein, Aso; Correa, Aps; Casali, Karina Rabello; Schaan, Beatriz D

    2016-01-20

    Physical exercise reduces glucose levels and glucose variability in patients with type 2 diabetes. Acute inspiratory muscle exercise has been shown to reduce these parameters in a small group of patients with type 2 diabetes, but these results have yet to be confirmed in a well-designed study. The aim of this study is to investigate the effect of acute inspiratory muscle exercise on glucose levels, glucose variability, and cardiovascular autonomic function in patients with type 2 diabetes. This study will use a randomized clinical trial crossover design. A total of 14 subjects will be recruited and randomly allocated to two groups to perform acute inspiratory muscle loading at 2 % of maximal inspiratory pressure (PImax, placebo load) or 60 % of PImax (experimental load). Inspiratory muscle training could be a novel exercise modality to be used to decrease glucose levels and glucose variability. ClinicalTrials.gov NCT02292810 .

  8. 78 FR 72864 - Drawn Stainless Steel Sinks From the People's Republic of China: Initiation of New Shipper Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-04

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-983] Drawn Stainless Steel Sinks... review of the antidumping duty order on drawn stainless steel sinks (``drawn sinks'') from the People's... merchandise. \\1\\ See Drawn Stainless Steel Sinks from the People's Republic of China: Amended Final...

  9. Emotion regulation and the dynamics of feelings: a conceptual and methodological framework.

    PubMed

    Hoeksma, Jan B; Oosterlaan, Jaap; Schipper, Eline M

    2004-01-01

    The emotional system is defined as a dynamical system that has neurological and biochemical structures that force the system to change in a regular and consistent way. This dynamic view allows for an alternative definition of emotion regulation, which describes when emotion regulation is needed, identifies its goal, and illustrates how regulation is achieved. The thesis developed here is that feelings-the private mental experience of emotion-play a crucial role in emotion regulation. Specifics of regulation are discussed and a parallel with parent-child interaction is drawn. It is shown that emotion regulation can be studied by looking at the variability of feelings. An illustrative application (N=30, age 10-13 years) shows that variability of anger is associated with the core executive function response inhibition.

  10. Exposing exposure: automated anatomy-specific CT radiation exposure extraction for quality assurance and radiation monitoring.

    PubMed

    Sodickson, Aaron; Warden, Graham I; Farkas, Cameron E; Ikuta, Ichiro; Prevedello, Luciano M; Andriole, Katherine P; Khorasani, Ramin

    2012-08-01

    To develop and validate an informatics toolkit that extracts anatomy-specific computed tomography (CT) radiation exposure metrics (volume CT dose index and dose-length product) from existing digital image archives through optical character recognition of CT dose report screen captures (dose screens) combined with Digital Imaging and Communications in Medicine attributes. This institutional review board-approved HIPAA-compliant study was performed in a large urban health care delivery network. Data were drawn from a random sample of CT encounters that occurred between 2000 and 2010; images from these encounters were contained within the enterprise image archive, which encompassed images obtained at an adult academic tertiary referral hospital and its affiliated sites, including a cancer center, a community hospital, and outpatient imaging centers, as well as images imported from other facilities. Software was validated by using 150 randomly selected encounters for each major CT scanner manufacturer, with outcome measures of dose screen retrieval rate (proportion of correctly located dose screens) and anatomic assignment precision (proportion of extracted exposure data with correctly assigned anatomic region, such as head, chest, or abdomen and pelvis). The 95% binomial confidence intervals (CIs) were calculated for discrete proportions, and CIs were derived from the standard error of the mean for continuous variables. After validation, the informatics toolkit was used to populate an exposure repository from a cohort of 54 549 CT encounters; of which 29 948 had available dose screens. Validation yielded a dose screen retrieval rate of 99% (597 of 605 CT encounters; 95% CI: 98%, 100%) and an anatomic assignment precision of 94% (summed DLP fraction correct 563 in 600 CT encounters; 95% CI: 92%, 96%). Patient safety applications of the resulting data repository include benchmarking between institutions, CT protocol quality control and optimization, and cumulative patient- and anatomy-specific radiation exposure monitoring. Large-scale anatomy-specific radiation exposure data repositories can be created with high fidelity from existing digital image archives by using open-source informatics tools.

  11. Point process analysis of noise in early invertebrate vision

    PubMed Central

    Vinnicombe, Glenn

    2017-01-01

    Noise is a prevalent and sometimes even dominant aspect of many biological processes. While many natural systems have adapted to attenuate or even usefully integrate noise, the variability it introduces often still delimits the achievable precision across biological functions. This is particularly so for visual phototransduction, the process responsible for converting photons of light into usable electrical signals (quantum bumps). Here, randomness of both the photon inputs (regarded as extrinsic noise) and the conversion process (intrinsic noise) are seen as two distinct, independent and significant limitations on visual reliability. Past research has attempted to quantify the relative effects of these noise sources by using approximate methods that do not fully account for the discrete, point process and time ordered nature of the problem. As a result the conclusions drawn from these different approaches have led to inconsistent expositions of phototransduction noise performance. This paper provides a fresh and complete analysis of the relative impact of intrinsic and extrinsic noise in invertebrate phototransduction using minimum mean squared error reconstruction techniques based on Bayesian point process (Snyder) filters. An integrate-fire based algorithm is developed to reliably estimate photon times from quantum bumps and Snyder filters are then used to causally estimate random light intensities both at the front and back end of the phototransduction cascade. Comparison of these estimates reveals that the dominant noise source transitions from extrinsic to intrinsic as light intensity increases. By extending the filtering techniques to account for delays, it is further found that among the intrinsic noise components, which include bump latency (mean delay and jitter) and shape (amplitude and width) variance, it is the mean delay that is critical to noise performance. As the timeliness of visual information is important for real-time action, this delay could potentially limit the speed at which invertebrates can respond to stimuli. Consequently, if one wants to increase visual fidelity, reducing the photoconversion lag is much more important than improving the regularity of the electrical signal. PMID:29077703

  12. Effects of lifestyle intervention using patient-centered cognitive behavioral therapy among patients with cardio-metabolic syndrome: a randomized, controlled trial.

    PubMed

    Zhang, Ying; Mei, Songli; Yang, Rui; Chen, Ling; Gao, Hang; Li, Li

    2016-11-18

    Cardio-metabolic syndrome (CMS) is a highly prevalent condition. There is an urgent need to identify effective and integrated multi-disciplinary approaches that can reduce risk factors for CMS. Sixty-two patients with a history of CMS were randomized 1:1 into two groups: a standard information -only group (control), or a self-regulated lifestyle waist circumference (patient-centered cognitive behavioral therapy) intervention group. A pretest and posttest, controlled, experimental design was used. Outcomes were measured at the baseline (week 0) and at the end of intervention (week 12). Comparisons were drawn between groups and over time. The mean (standard deviation) age of the subjects was 48.6 (5.8) years ranging from 32 to 63, and 56.9% of the participants were female. Both groups showed no significant differences in Demographic variables and the metabolic syndrome indicators at baseline. While the control group only showed modest improvement after 12 weeks, compared to baseline, the intervention group demonstrated significant improvement from baseline. This study controlled for patients' demographics and baseline characteristics when assessing the effects of intervention. After adjusting for age, education and baseline level, the experimental group and the control group were statistically significant different in the following post-treatment outcomes: WC (F = 35.96, P < 0.001), TG (F = 18.93, P < 0.001), RSBP (F = 33.89, P < 0.001) and SF-36(F = 157.93, P < 0.001). The results showed patients' age and education were not strong predictors of patients' outcome (including WC, TG, RSBP and SF-36). Lifestyle intervention on patient-centered cognitive behavioral therapy can improve the physical and mental health conditions among individuals reporting a history of cardio-metabolic syndrome, and possibly provided preliminary benefits for the treatment of CMS. Chinese Clinical Trial Register #, ChiCTR15006148 .

  13. Renal stress and kidney injury biomarkers in response to endurance cycling in the heat with and without ibuprofen.

    PubMed

    McDermott, Brendon P; Smith, Cody R; Butts, Cory L; Caldwell, Aaron R; Lee, Elaine C; Vingren, Jakob L; Munoz, Colleen X; Kunces, Laura J; Williamson, Keith; Ganio, Matthew S; Armstrong, Lawrence E

    2018-05-16

    Exercise, especially in the heat, can contribute to acute kidney injury, which can expedite chronic kidney disease onset. The additional stress of ibuprofen use is hypothesized to increase renal stress. To observe the effects of endurance cycling in the heat on renal function. Secondarily, we investigated the effect of ibuprofen ingestion on kidney stress. Randomized, placebo controlled and observational methods were utilized. Forty cyclists (52±9y, 21.7±6.5% body fat) volunteered and completed an endurance cycling event (5.7±1.2h) in the heat (33.2±5.0°C, 38.4±10.7% RH). Thirty-five participants were randomized to ingest a placebo (n=17) or 600mg ibuprofen (n=18) pre-event. A blood sample was drawn before and following the event. Serum creatinine was assessed by colorimetric assay. An ELISA was used to measure serum neutrophil gelatinase-associated lipocalin. Fractional excretion of sodium was calculated after urinary and serum electrolyte analyses. Placebo versus ibuprofen groups contributed no significant difference in any variable (p>0.05). Serum creatinine significantly increased from pre- (0.52±0.14mg/dL) to post-event (0.88±0.21mg/dL; p<0.001). Serum neutrophil gelatinase-associated lipocalin significantly increased (pre: 68.51±17.54ng/mL; post: 139.12±36.52ng/mL; p<0.001) and fractional excretion of sodium was significantly reduced from pre- (0.52±0.24%) to post-event (0.27±0.18%; p<0.001). Changes in renal biomarkers suggest mild acute kidney injury and reduced kidney function during a single bout of endurance cycling in the heat, without influence from moderate ibuprofen ingestion. Copyright © 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  14. An Integrated Probabilistic-Fuzzy Assessment of Uncertainty Associated with Human Health Risk to MSW Landfill Leachate Contamination

    NASA Astrophysics Data System (ADS)

    Mishra, H.; Karmakar, S.; Kumar, R.

    2016-12-01

    Risk assessment will not remain simple when it involves multiple uncertain variables. Uncertainties in risk assessment majorly results from (1) the lack of knowledge of input variable (mostly random), and (2) data obtained from expert judgment or subjective interpretation of available information (non-random). An integrated probabilistic-fuzzy health risk approach has been proposed for simultaneous treatment of random and non-random uncertainties associated with input parameters of health risk model. The LandSim 2.5, a landfill simulator, has been used to simulate the Turbhe landfill (Navi Mumbai, India) activities for various time horizons. Further the LandSim simulated six heavy metals concentration in ground water have been used in the health risk model. The water intake, exposure duration, exposure frequency, bioavailability and average time are treated as fuzzy variables, while the heavy metals concentration and body weight are considered as probabilistic variables. Identical alpha-cut and reliability level are considered for fuzzy and probabilistic variables respectively and further, uncertainty in non-carcinogenic human health risk is estimated using ten thousand Monte-Carlo simulations (MCS). This is the first effort in which all the health risk variables have been considered as non-deterministic for the estimation of uncertainty in risk output. The non-exceedance probability of Hazard Index (HI), summation of hazard quotients, of heavy metals of Co, Cu, Mn, Ni, Zn and Fe for male and female population have been quantified and found to be high (HI>1) for all the considered time horizon, which evidently shows possibility of adverse health effects on the population residing near Turbhe landfill.

  15. Optimizing a Sensor Network with Data from Hazard Mapping Demonstrated in a Heavy-Vehicle Manufacturing Facility.

    PubMed

    Berman, Jesse D; Peters, Thomas M; Koehler, Kirsten A

    2018-05-28

    To design a method that uses preliminary hazard mapping data to optimize the number and location of sensors within a network for a long-term assessment of occupational concentrations, while preserving temporal variability, accuracy, and precision of predicted hazards. Particle number concentrations (PNCs) and respirable mass concentrations (RMCs) were measured with direct-reading instruments in a large heavy-vehicle manufacturing facility at 80-82 locations during 7 mapping events, stratified by day and season. Using kriged hazard mapping, a statistical approach identified optimal orders for removing locations to capture temporal variability and high prediction precision of PNC and RMC concentrations. We compared optimal-removal, random-removal, and least-optimal-removal orders to bound prediction performance. The temporal variability of PNC was found to be higher than RMC with low correlation between the two particulate metrics (ρ = 0.30). Optimal-removal orders resulted in more accurate PNC kriged estimates (root mean square error [RMSE] = 49.2) at sample locations compared with random-removal order (RMSE = 55.7). For estimates at locations having concentrations in the upper 10th percentile, the optimal-removal order preserved average estimated concentrations better than random- or least-optimal-removal orders (P < 0.01). However, estimated average concentrations using an optimal-removal were not statistically different than random-removal when averaged over the entire facility. No statistical difference was observed for optimal- and random-removal methods for RMCs that were less variable in time and space than PNCs. Optimized removal performed better than random-removal in preserving high temporal variability and accuracy of hazard map for PNC, but not for the more spatially homogeneous RMC. These results can be used to reduce the number of locations used in a network of static sensors for long-term monitoring of hazards in the workplace, without sacrificing prediction performance.

  16. Managing water and salinity with desalination, conveyance, conservation, waste-water treatment and reuse to counteract climate variability in Gaza

    NASA Astrophysics Data System (ADS)

    Rosenberg, D. E.; Aljuaidi, A. E.; Kaluarachchi, J. J.

    2009-12-01

    We include demands for water of different salinity concentrations as input parameters and decision variables in a regional hydro-economic optimization model. This specification includes separate demand functions for saline water. We then use stochastic non-linear programming to jointly identify the benefit maximizing set of infrastructure expansions, operational allocations, and use of different water quality types under climate variability. We present a detailed application for the Gaza Strip. The application considers building desalination and waste-water treatment plants and conveyance pipelines, initiating water conservation and leak reduction programs, plus allocating and transferring water of different qualities among agricultural, industrial, and urban sectors and among districts. Results show how to integrate a mix of supply enhancement, conservation, water quality improvement, and water quality management actions into a portfolio that can economically and efficiently respond to changes and uncertainties in surface and groundwater availability due to climate variability. We also show how to put drawn-down and saline Gaza aquifer water to more sustainable and economical use.

  17. Impacts analysis of car following models considering variable vehicular gap policies

    NASA Astrophysics Data System (ADS)

    Xin, Qi; Yang, Nan; Fu, Rui; Yu, Shaowei; Shi, Zhongke

    2018-07-01

    Due to the important roles playing in the vehicles' adaptive cruise control system, variable vehicular gap polices were employed to full velocity difference model (FVDM) to investigate the traffic flow properties. In this paper, two new car following models were put forward by taking constant time headway(CTH) policy and variable time headway(VTH) policy into optimal velocity function, separately. By steady state analysis of the new models, an equivalent optimal velocity function was defined. To determine the linear stable conditions of the new models, we introduce equivalent expressions of safe vehicular gap, and then apply small amplitude perturbation analysis and long terms of wave expansion techniques to obtain the new models' linear stable conditions. Additionally, the first order approximate solutions of the new models were drawn at the stable region, by transforming the models into typical Burger's partial differential equations with reductive perturbation method. The FVDM based numerical simulations indicate that the variable vehicular gap polices with proper parameters directly contribute to the improvement of the traffic flows' stability and the avoidance of the unstable traffic phenomena.

  18. Variable Selection in the Presence of Missing Data: Imputation-based Methods.

    PubMed

    Zhao, Yize; Long, Qi

    2017-01-01

    Variable selection plays an essential role in regression analysis as it identifies important variables that associated with outcomes and is known to improve predictive accuracy of resulting models. Variable selection methods have been widely investigated for fully observed data. However, in the presence of missing data, methods for variable selection need to be carefully designed to account for missing data mechanisms and statistical techniques used for handling missing data. Since imputation is arguably the most popular method for handling missing data due to its ease of use, statistical methods for variable selection that are combined with imputation are of particular interest. These methods, valid used under the assumptions of missing at random (MAR) and missing completely at random (MCAR), largely fall into three general strategies. The first strategy applies existing variable selection methods to each imputed dataset and then combine variable selection results across all imputed datasets. The second strategy applies existing variable selection methods to stacked imputed datasets. The third variable selection strategy combines resampling techniques such as bootstrap with imputation. Despite recent advances, this area remains under-developed and offers fertile ground for further research.

  19. The MASIV Survey - IV. Relationship between intra-day scintillation and intrinsic variability of radio AGNs

    NASA Astrophysics Data System (ADS)

    Koay, J. Y.; Macquart, J.-P.; Jauncey, D. L.; Pursimo, T.; Giroletti, M.; Bignall, H. E.; Lovell, J. E. J.; Rickett, B. J.; Kedziora-Chudczer, L.; Ojha, R.; Reynolds, C.

    2018-03-01

    We investigate the relationship between 5 GHz interstellar scintillation (ISS) and 15 GHz intrinsic variability of compact, radio-selected active galactic nuclei (AGNs) drawn from the Microarcsecond Scintillation-Induced Variability (MASIV) Survey and the Owens Valley Radio Observatory blazar monitoring program. We discover that the strongest scintillators at 5 GHz (modulation index, m5 ≥ 0.02) all exhibit strong 15 GHz intrinsic variability (m15 ≥ 0.1). This relationship can be attributed mainly to the mutual dependence of intrinsic variability and ISS amplitudes on radio core compactness at ˜ 100 μas scales, and to a lesser extent, on their mutual dependences on source flux density, arcsec-scale core dominance and redshift. However, not all sources displaying strong intrinsic variations show high amplitude scintillation, since ISS is also strongly dependent on Galactic line-of-sight scattering properties. This observed relationship between intrinsic variability and ISS highlights the importance of optimizing the observing frequency, cadence, timespan and sky coverage of future radio variability surveys, such that these two effects can be better distinguished to study the underlying physics. For the full MASIV sample, we find that Fermi-detected gamma-ray loud sources exhibit significantly higher 5 GHz ISS amplitudes than gamma-ray quiet sources. This relationship is weaker than the known correlation between gamma-ray loudness and the 15 GHz variability amplitudes, most likely due to jet opacity effects.

  20. Observational studies of patients in the emergency department: a comparison of 4 sampling methods.

    PubMed

    Valley, Morgan A; Heard, Kennon J; Ginde, Adit A; Lezotte, Dennis C; Lowenstein, Steven R

    2012-08-01

    We evaluate the ability of 4 sampling methods to generate representative samples of the emergency department (ED) population. We analyzed the electronic records of 21,662 consecutive patient visits at an urban, academic ED. From this population, we simulated different models of study recruitment in the ED by using 2 sample sizes (n=200 and n=400) and 4 sampling methods: true random, random 4-hour time blocks by exact sample size, random 4-hour time blocks by a predetermined number of blocks, and convenience or "business hours." For each method and sample size, we obtained 1,000 samples from the population. Using χ(2) tests, we measured the number of statistically significant differences between the sample and the population for 8 variables (age, sex, race/ethnicity, language, triage acuity, arrival mode, disposition, and payer source). Then, for each variable, method, and sample size, we compared the proportion of the 1,000 samples that differed from the overall ED population to the expected proportion (5%). Only the true random samples represented the population with respect to sex, race/ethnicity, triage acuity, mode of arrival, language, and payer source in at least 95% of the samples. Patient samples obtained using random 4-hour time blocks and business hours sampling systematically differed from the overall ED patient population for several important demographic and clinical variables. However, the magnitude of these differences was not large. Common sampling strategies selected for ED-based studies may affect parameter estimates for several representative population variables. However, the potential for bias for these variables appears small. Copyright © 2012. Published by Mosby, Inc.

  1. Key-Generation Algorithms for Linear Piece In Hand Matrix Method

    NASA Astrophysics Data System (ADS)

    Tadaki, Kohtaro; Tsujii, Shigeo

    The linear Piece In Hand (PH, for short) matrix method with random variables was proposed in our former work. It is a general prescription which can be applicable to any type of multivariate public-key cryptosystems for the purpose of enhancing their security. Actually, we showed, in an experimental manner, that the linear PH matrix method with random variables can certainly enhance the security of HFE against the Gröbner basis attack, where HFE is one of the major variants of multivariate public-key cryptosystems. In 1998 Patarin, Goubin, and Courtois introduced the plus method as a general prescription which aims to enhance the security of any given MPKC, just like the linear PH matrix method with random variables. In this paper we prove the equivalence between the plus method and the primitive linear PH matrix method, which is introduced by our previous work to explain the notion of the PH matrix method in general in an illustrative manner and not for a practical use to enhance the security of any given MPKC. Based on this equivalence, we show that the linear PH matrix method with random variables has the substantial advantage over the plus method with respect to the security enhancement. In the linear PH matrix method with random variables, the three matrices, including the PH matrix, play a central role in the secret-key and public-key. In this paper, we clarify how to generate these matrices and thus present two probabilistic polynomial-time algorithms to generate these matrices. In particular, the second one has a concise form, and is obtained as a byproduct of the proof of the equivalence between the plus method and the primitive linear PH matrix method.

  2. A New Trait-Based Auto-Emergent Model for Zooplankton and Confrontation with Size-Structured Observations from the Bay of Biscay

    NASA Astrophysics Data System (ADS)

    Vandromme, Pieter; Sourisseau, Marc; Huret, Martin

    2013-04-01

    Zooplankton plays a significant role in marine ecosystems bridging the gap between primary producers and top consumers and interacting with the particle flux through complex dynamics. Scarcity of data and complexity of observing zooplankton make it difficult to integrate it in biogeochemical models where it is most often formulated in a simpler manner, i.e. classic box models with usually two compartments (micro and meso/macro zooplankton). Recent advances in automatic sizing, counting and identification allow better estimates of the dynamics and distribution of zooplankton, notably through the measurement of its size structure, and for zooplankton size matter. Most zooplankton physiological rates as well as predator:prey interactions can be significantly relied to individuals size through allometric relations. Such size-dependency was used in recent models. Yet, these models were neither confronted to observations nor integrated in 3D biogeochemical models. Here we propose a newly developed model of zooplankton dynamics based on size-dependent allometric relations but which allows various diet types regardless of the size. A size and a degree of herbivory is randomly drawn for each zooplankton species generated within the model (up to 400 here, limited by actual computational costs). By generating random degree of herbivory zooplankton species of same size could have various diet (from herbivore to carnivore). Other parameters leading to various reproductive strategies or vertical migration could also be drawn randomly (not tested here). The zooplankton model is coupled to the 3D biogeochemical model MARS3D on a test case representing a simplified view of the Bay of Biscay (i.e., continental shelf, estuary, tides). The model shows auto-emergent properties with the selection of size/diet most adapted to local conditions (here offshore vs. coastal, estuary…). Then, patterns of the modeled size-structure of the zooplankton are confronted to the ones observed during Spring-time cruises in the Bay of Biscay. The usefulness of the proposed zooplankton model for large scale biogeochemical models is further discussed.

  3. Variable versus conventional lung protective mechanical ventilation during open abdominal surgery: study protocol for a randomized controlled trial.

    PubMed

    Spieth, Peter M; Güldner, Andreas; Uhlig, Christopher; Bluth, Thomas; Kiss, Thomas; Schultz, Marcus J; Pelosi, Paolo; Koch, Thea; Gama de Abreu, Marcelo

    2014-05-02

    General anesthesia usually requires mechanical ventilation, which is traditionally accomplished with constant tidal volumes in volume- or pressure-controlled modes. Experimental studies suggest that the use of variable tidal volumes (variable ventilation) recruits lung tissue, improves pulmonary function and reduces systemic inflammatory response. However, it is currently not known whether patients undergoing open abdominal surgery might benefit from intraoperative variable ventilation. The PROtective VARiable ventilation trial ('PROVAR') is a single center, randomized controlled trial enrolling 50 patients who are planning for open abdominal surgery expected to last longer than 3 hours. PROVAR compares conventional (non-variable) lung protective ventilation (CV) with variable lung protective ventilation (VV) regarding pulmonary function and inflammatory response. The primary endpoint of the study is the forced vital capacity on the first postoperative day. Secondary endpoints include further lung function tests, plasma cytokine levels, spatial distribution of ventilation assessed by means of electrical impedance tomography and postoperative pulmonary complications. We hypothesize that VV improves lung function and reduces systemic inflammatory response compared to CV in patients receiving mechanical ventilation during general anesthesia for open abdominal surgery longer than 3 hours. PROVAR is the first randomized controlled trial aiming at intra- and postoperative effects of VV on lung function. This study may help to define the role of VV during general anesthesia requiring mechanical ventilation. Clinicaltrials.gov NCT01683578 (registered on September 3 3012).

  4. A Random Variable Transformation Process.

    ERIC Educational Resources Information Center

    Scheuermann, Larry

    1989-01-01

    Provides a short BASIC program, RANVAR, which generates random variates for various theoretical probability distributions. The seven variates include: uniform, exponential, normal, binomial, Poisson, Pascal, and triangular. (MVL)

  5. A Cautious Note on Auxiliary Variables That Can Increase Bias in Missing Data Problems.

    PubMed

    Thoemmes, Felix; Rose, Norman

    2014-01-01

    The treatment of missing data in the social sciences has changed tremendously during the last decade. Modern missing data techniques such as multiple imputation and full-information maximum likelihood are used much more frequently. These methods assume that data are missing at random. One very common approach to increase the likelihood that missing at random is achieved consists of including many covariates as so-called auxiliary variables. These variables are either included based on data considerations or in an inclusive fashion; that is, taking all available auxiliary variables. In this article, we point out that there are some instances in which auxiliary variables exhibit the surprising property of increasing bias in missing data problems. In a series of focused simulation studies, we highlight some situations in which this type of biasing behavior can occur. We briefly discuss possible ways how one can avoid selecting bias-inducing covariates as auxiliary variables.

  6. Detecting Random, Partially Random, and Nonrandom Minnesota Multiphasic Personality Inventory-2 Protocols

    ERIC Educational Resources Information Center

    Pinsoneault, Terry B.

    2007-01-01

    The ability of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2; J. N. Butcher et al., 2001) validity scales to detect random, partially random, and nonrandom MMPI-2 protocols was investigated. Investigations included the Variable Response Inconsistency scale (VRIN), F, several potentially useful new F and VRIN subscales, and F-sub(b) - F…

  7. Uncertainty in Random Forests: What does it mean in a spatial context?

    NASA Astrophysics Data System (ADS)

    Klump, Jens; Fouedjio, Francky

    2017-04-01

    Geochemical surveys are an important part of exploration for mineral resources and in environmental studies. The samples and chemical analyses are often laborious and difficult to obtain and therefore come at a high cost. As a consequence, these surveys are characterised by datasets with large numbers of variables but relatively few data points when compared to conventional big data problems. With more remote sensing platforms and sensor networks being deployed, large volumes of auxiliary data of the surveyed areas are becoming available. The use of these auxiliary data has the potential to improve the prediction of chemical element concentrations over the whole study area. Kriging is a well established geostatistical method for the prediction of spatial data but requires significant pre-processing and makes some basic assumptions about the underlying distribution of the data. Some machine learning algorithms, on the other hand, may require less data pre-processing and are non-parametric. In this study we used a dataset provided by Kirkwood et al. [1] to explore the potential use of Random Forest in geochemical mapping. We chose Random Forest because it is a well understood machine learning method and has the advantage that it provides us with a measure of uncertainty. By comparing Random Forest to Kriging we found that both methods produced comparable maps of estimated values for our variables of interest. Kriging outperformed Random Forest for variables of interest with relatively strong spatial correlation. The measure of uncertainty provided by Random Forest seems to be quite different to the measure of uncertainty provided by Kriging. In particular, the lack of spatial context can give misleading results in areas without ground truth data. In conclusion, our preliminary results show that the model driven approach in geostatistics gives us more reliable estimates for our target variables than Random Forest for variables with relatively strong spatial correlation. However, in cases of weak spatial correlation Random Forest, as a nonparametric method, may give the better results once we have a better understanding of the meaning of its uncertainty measures in a spatial context. References [1] Kirkwood, C., M. Cave, D. Beamish, S. Grebby, and A. Ferreira (2016), A machine learning approach to geochemical mapping, Journal of Geochemical Exploration, 163, 28-40, doi:10.1016/j.gexplo.2016.05.003.

  8. SU-C-BRB-05: Determining the Adequacy of Auto-Contouring Via Probabilistic Assessment of Ensuing Treatment Plan Metrics in Comparison with Manual Contours

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

    Nourzadeh, H; Watkins, W; Siebers, J

    Purpose: To determine if auto-contour and manual-contour—based plans differ when evaluated with respect to probabilistic coverage metrics and biological model endpoints for prostate IMRT. Methods: Manual and auto-contours were created for 149 CT image sets acquired from 16 unique prostate patients. A single physician manually contoured all images. Auto-contouring was completed utilizing Pinnacle’s Smart Probabilistic Image Contouring Engine (SPICE). For each CT, three different 78 Gy/39 fraction 7-beam IMRT plans are created; PD with drawn ROIs, PAS with auto-contoured ROIs, and PM with auto-contoured OARs with the manually drawn target. For each plan, 1000 virtual treatment simulations with different sampledmore » systematic errors for each simulation and a different sampled random error for each fraction were performed using our in-house GPU-accelerated robustness analyzer tool which reports the statistical probability of achieving dose-volume metrics, NTCP, TCP, and the probability of achieving the optimization criteria for both auto-contoured (AS) and manually drawn (D) ROIs. Metrics are reported for all possible cross-evaluation pairs of ROI types (AS,D) and planning scenarios (PD,PAS,PM). Bhattacharyya coefficient (BC) is calculated to measure the PDF similarities for the dose-volume metric, NTCP, TCP, and objectives with respect to the manually drawn contour evaluated on base plan (D-PD). Results: We observe high BC values (BC≥0.94) for all OAR objectives. BC values of max dose objective on CTV also signify high resemblance (BC≥0.93) between the distributions. On the other hand, BC values for CTV’s D95 and Dmin objectives are small for AS-PM, AS-PD. NTCP distributions are similar across all evaluation pairs, while TCP distributions of AS-PM, AS-PD sustain variations up to %6 compared to other evaluated pairs. Conclusion: No significant probabilistic differences are observed in the metrics when auto-contoured OARs are used. The prostate auto-contour needs improvement to achieve clinically equivalent plans.« less

  9. On the genre-fication of music: a percolation approach

    NASA Astrophysics Data System (ADS)

    Lambiotte, R.; Ausloos, M.

    2006-03-01

    We analyze web-downloaded data on people sharing their music library. By attributing to each music group usual music genres (Rock, Pop ...), and analysing correlations between music groups of different genres with percolation-idea based methods, we probe the reality of these subdivisions and construct a music genre cartography, with a tree representation. We also discuss an alternative objective way to classify music, that is based on the complex structure of the groups audience. Finally, a link is drawn with the theory of hidden variables in complex networks.

  10. Characteristics of ovulation method acceptors: a cross-cultural assessment.

    PubMed

    Klaus, H; Labbok, M; Barker, D

    1988-01-01

    Five programs of instruction in the ovulation method (OM) in diverse geographic and cultural settings are described, and characteristics of approximately 200 consecutive OM acceptors in each program are examined. Major findings include: the religious background and family size of acceptors are variable, as is the level of previous contraceptive use. Acceptors are drawn from a wide range of socioeconomic and religious backgrounds; however, family planning intention was similarly distributed in all five countries. In sum, the ovulation method is accepted by persons from a variety of backgrounds within and between cultural setting.

  11. Analytical tools and isolation of TOF events

    NASA Technical Reports Server (NTRS)

    Wolf, H.

    1974-01-01

    Analytical tools are presented in two reports. The first is a probability analysis of the orbital distribution of events in relation to dust flux density observed in Pioneer 8 and 9 distributions. A distinction is drawn between asymmetries caused by random fluctuations and systematic variations, by calculating the probability of any particular asymmetry. The second article discusses particle trajectories for a repulsive force field. The force on a particle due to solar radiation pressure is directed along the particle's radius vector, from the sun, and is inversely proportional to its distance from the sun. Equations of motion which describe both solar radiation pressure and gravitational attraction are presented.

  12. Oil Extraction and Indigenous Livelihoods in the Northern Ecuadorian Amazon

    PubMed Central

    Bozigar, Matthew; Gray, Clark L.; Bilsborrow, Richard E.

    2015-01-01

    Globally, the extraction of minerals and fossil fuels is increasingly penetrating into isolated regions inhabited by indigenous peoples, potentially undermining their livelihoods and well-being. To provide new insight to this issue, we draw on a unique longitudinal dataset collected in the Ecuadorian Amazon over an 11-year period from 484 indigenous households with varying degrees of exposure to oil extraction. Fixed and random effects regression models of the consequences of oil activities for livelihood outcomes reveal mixed and multidimensional effects. These results challenge common assumptions about these processes and are only partly consistent with hypotheses drawn from the Dutch disease literature. PMID:26543302

  13. Reliability Overhaul Model

    DTIC Science & Technology

    1989-08-01

    Random variables for the conditional exponential distribution are generated using the inverse transform method. C1) Generate U - UCO,i) (2) Set s - A ln...e - [(x+s - 7)/ n] 0 + [Cx-T)/n]0 c. Random variables from the conditional weibull distribution are generated using the inverse transform method. C1...using a standard normal transformation and the inverse transform method. B - 3 APPENDIX 3 DISTRIBUTIONS SUPPORTED BY THE MODEL (1) Generate Y - PCX S

  14. Performance of DS/SSMA (Direct-Sequence Spread-Spectrum Multiple-Access) Communications in Impulsive Channels.

    DTIC Science & Technology

    1986-11-01

    mother and my brother. Their support and encouragement made this research exciting and enjoyable. I am grateful to my advisor, Professor H. Vincent Poor...the model. The m! M A variance of a random variable with density given by (A. 1) is a2 KmC 2 2A(I+l’)• (A.2) With the variance of the random variable

  15. Addressing variability in the acoustic startle reflex for accurate gap detection assessment.

    PubMed

    Longenecker, Ryan J; Kristaponyte, Inga; Nelson, Gregg L; Young, Jesse W; Galazyuk, Alexander V

    2018-06-01

    The acoustic startle reflex (ASR) is subject to substantial variability. This inherent variability consequently shapes the conclusions drawn from gap-induced prepulse inhibition of the acoustic startle reflex (GPIAS) assessments. Recent studies have cast doubt as to the efficacy of this methodology as it pertains to tinnitus assessment, partially, due to variability in and between data sets. The goal of this study was to examine the variance associated with several common data collection variables and data analyses with the aim to improve GPIAS reliability. To study this the GPIAS tests were conducted in adult male and female CBA/CaJ mice. Factors such as inter-trial interval, circadian rhythm, sex differences, and sensory adaptation were each evaluated. We then examined various data analysis factors which influence GPIAS assessment. Gap-induced facilitation, data processing options, and assessments of tinnitus were studied. We found that the startle reflex is highly variable in CBA/CaJ mice, but this can be minimized by certain data collection factors. We also found that careful consideration of temporal fluctuations of the ASR and controlling for facilitation can lead to more accurate GPIAS results. This study provides a guide for reducing variance in the GPIAS methodology - thereby improving the diagnostic power of the test. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Access to health care and community social capital.

    PubMed

    Hendryx, Michael S; Ahern, Melissa M; Lovrich, Nicholas P; McCurdy, Arthur H

    2002-02-01

    To test the hypothesis that variation in reported access to health care is positively related to the level of social capital present in a community. The 1996 Household Survey of the Community Tracking Study, drawn from 22 metropolitan statistical areas across the United States (n = 19,672). Additional data for the 22 communities are from a 1996 multicity broadcast media marketing database, including key social capital indicators, the 1997 National Profile of Local Health Departments survey, and Interstudy, American Hospital Association, and American Medical Association sources. The design is cross-sectional. Self-reported access to care problems is the dependent variable. Independent variables include individual sociodemographic variables, community-level health sector variables, and social capital variables. Data are merged from the various sources and weighted to be population representative and are analyzed using hierarchical categorical modeling. Persons who live in metropolitan statistical areas featuring higher levels of social capital report fewer problems accessing health care. A higher HMO penetration rate in a metropolitan statistical area was also associated with fewer access problems. Other health sector variables were not related to health care access. The results observed for 22 major U.S. cities are consistent with the hypothesis that community social capital enables better access to care, perhaps through improving community accountability mechanisms.

  17. Sea Surface Temperature and Ocean Color Variability in the South China Sea

    NASA Astrophysics Data System (ADS)

    Conaty, A. P.

    2001-12-01

    The South China Sea is a marginal sea in the Southeast Asian region whose surface circulation is driven by monsoons and whose surface currents have complex seasonal patterns. Its rich natural resources and strategic location have made its small islands areas of political dispute among the neighboring nations. This study aims to show the seasonal and interannual variability of sea surface temperature and ocean color in South China Sea. It makes use of NOAA's Advanced Very High Resolution Radiometer (AVHRR) satellite data sets on sea surface temperature for the period 1981-2000 and NASA's Nimbus-7 Coastal Zone Color Scanner (CZCS) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite data sets on pigment concentration (ocean color) for the period 1981-1996 and 1997-2000, respectively. Transect lines were drawn along several potential hotspot areas to show the variability in sea surface temperature and pigment concentration through time. In-situ data on sea surface temperature along South China Sea were likewise plotted to see the variability with time. Higher seasonal variability in sea surface temperature was seen at higher latitudes. Interannual variability was within 1-3 Kelvin. In most areas, pigment concentration was higher during northern hemisphere winter and autumn, after the monsoon rains, with a maximum of 30 milligrams per cubic meter.

  18. A New Approach to Extreme Value Estimation Applicable to a Wide Variety of Random Variables

    NASA Technical Reports Server (NTRS)

    Holland, Frederic A., Jr.

    1997-01-01

    Designing reliable structures requires an estimate of the maximum and minimum values (i.e., strength and load) that may be encountered in service. Yet designs based on very extreme values (to insure safety) can result in extra material usage and hence, uneconomic systems. In aerospace applications, severe over-design cannot be tolerated making it almost mandatory to design closer to the assumed limits of the design random variables. The issue then is predicting extreme values that are practical, i.e. neither too conservative or non-conservative. Obtaining design values by employing safety factors is well known to often result in overly conservative designs and. Safety factor values have historically been selected rather arbitrarily, often lacking a sound rational basis. To answer the question of how safe a design needs to be has lead design theorists to probabilistic and statistical methods. The so-called three-sigma approach is one such method and has been described as the first step in utilizing information about the data dispersion. However, this method is based on the assumption that the random variable is dispersed symmetrically about the mean and is essentially limited to normally distributed random variables. Use of this method can therefore result in unsafe or overly conservative design allowables if the common assumption of normality is incorrect.

  19. On Probability Domains IV

    NASA Astrophysics Data System (ADS)

    Frič, Roman; Papčo, Martin

    2017-12-01

    Stressing a categorical approach, we continue our study of fuzzified domains of probability, in which classical random events are replaced by measurable fuzzy random events. In operational probability theory (S. Bugajski) classical random variables are replaced by statistical maps (generalized distribution maps induced by random variables) and in fuzzy probability theory (S. Gudder) the central role is played by observables (maps between probability domains). We show that to each of the two generalized probability theories there corresponds a suitable category and the two resulting categories are dually equivalent. Statistical maps and observables become morphisms. A statistical map can send a degenerated (pure) state to a non-degenerated one —a quantum phenomenon and, dually, an observable can map a crisp random event to a genuine fuzzy random event —a fuzzy phenomenon. The dual equivalence means that the operational probability theory and the fuzzy probability theory coincide and the resulting generalized probability theory has two dual aspects: quantum and fuzzy. We close with some notes on products and coproducts in the dual categories.

  20. Tests of Hypotheses Arising In the Correlated Random Coefficient Model*

    PubMed Central

    Heckman, James J.; Schmierer, Daniel

    2010-01-01

    This paper examines the correlated random coefficient model. It extends the analysis of Swamy (1971), who pioneered the uncorrelated random coefficient model in economics. We develop the properties of the correlated random coefficient model and derive a new representation of the variance of the instrumental variable estimator for that model. We develop tests of the validity of the correlated random coefficient model against the null hypothesis of the uncorrelated random coefficient model. PMID:21170148

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