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1

Pearson's Correlation Coefficient  

NSDL National Science Digital Library

This tutorial on Pearson's Correlation Coefficient includes the definition, assumptions, and characteristics of r as well as related statistics and hypothesis test procedures. One section instructs users to find correlation in the WINKS software, but those without the software can still use the tutorial. An exercise is given at the end that can be done with any statistical software package.

2009-01-09

2

Correlation Structure of Fractional Pearson Diffusions  

PubMed Central

The stochastic solution to a diffusion equations with polynomial coefficients is called a Pearson diffusion. If the first time derivative is replaced by a Caputo fractional derivative of order less than one, the stochastic solution is called a fractional Pearson diffusion. This paper develops an explicit formula for the covariance function of a fractional Pearson diffusion in steady state, in terms of Mittag-Leffler functions. That formula shows that fractional Pearson diffusions are long range dependent, with a correlation that falls off like a power law, whose exponent equals the order of the fractional derivative. PMID:24089586

Leonenko, Nikolai N.; Meerschaert, Mark M.; Sikorskii, Alla

2013-01-01

3

The Evolution of Pearson's Correlation Coefficient  

ERIC Educational Resources Information Center

This article describes an activity for developing the notion of association between two quantitative variables. By exploring a collection of scatter plots, the authors propose a nonstandard "intuitive" measure of association; and by examining properties of this measure, they develop the more standard measure, Pearson's Correlation Coefficient. The…

Kader, Gary D.; Franklin, Christine A.

2008-01-01

4

Pearson's Product-Moment Coefficient of Correlation  

NSDL National Science Digital Library

This tutorial, created by Thomas W. MacFarland of Nova Southeastern University, explains the theory and use of Pearson's Product Moment Coefficient of Correlation and demonstrates it with an example on GPA and test scores. Data sets are provided in both SPSS and Minitab code. This is a great resource for anyone looking for a more in-depth study of statistics. This could be used as either a teaching guide for educators or simply further practice for students.

Macfarland, Thomas W.

2009-09-11

5

Random matrix theory analysis of cross-correlations in the US stock market: Evidence from Pearson’s correlation coefficient and detrended cross-correlation coefficient  

NASA Astrophysics Data System (ADS)

In this study, we first build two empirical cross-correlation matrices in the US stock market by two different methods, namely the Pearson’s correlation coefficient and the detrended cross-correlation coefficient (DCCA coefficient). Then, combining the two matrices with the method of random matrix theory (RMT), we mainly investigate the statistical properties of cross-correlations in the US stock market. We choose the daily closing prices of 462 constituent stocks of S&P 500 index as the research objects and select the sample data from January 3, 2005 to August 31, 2012. In the empirical analysis, we examine the statistical properties of cross-correlation coefficients, the distribution of eigenvalues, the distribution of eigenvector components, and the inverse participation ratio. From the two methods, we find some new results of the cross-correlations in the US stock market in our study, which are different from the conclusions reached by previous studies. The empirical cross-correlation matrices constructed by the DCCA coefficient show several interesting properties at different time scales in the US stock market, which are useful to the risk management and optimal portfolio selection, especially to the diversity of the asset portfolio. It will be an interesting and meaningful work to find the theoretical eigenvalue distribution of a completely random matrix R for the DCCA coefficient because it does not obey the Mar?enko-Pastur distribution.

Wang, Gang-Jin; Xie, Chi; Chen, Shou; Yang, Jiao-Jiao; Yang, Ming-Yan

2013-09-01

6

High-Rate Vector Quantization for the Neyman–Pearson Detection of Correlated Processes  

Microsoft Academic Search

This paper investigates the effect of quantization on the performance of the Neyman-Pearson test. It is assumed that a sensing unit observes samples of a correlated stationary ergodic multivariate process. Each sample is passed through an -point quantizer and transmitted to a decision device which performs a binary hypothesis test. For any false alarm level, it is shown that the

Joffrey Villard; Pascal Bianchi

2011-01-01

7

Classification of evoked potentials by Pearson's correlation in a Brain-Computer Interface  

E-print Network

Classification of evoked potentials by Pearson's correlation in a Brain-Computer Interface F learn- ing technique for use in a brain-computer interface. Electroencephalogram (EEG) signals ac collected from eight individuals. Keywords: Brain-computer interface; BCI; linear classifier; evoked

Paris-Sud XI, Université de

8

Correlation ResultsCorrelation Results 1) Multiple Pearson correlation tests were used to explore  

E-print Network

to explore whether or not significant relationships exist between several measures of the deer ankle bone be rejected. 4) Ankle bone size in deer positively correlates with weight and4) Ankle bone size in deer resultsMultiple Regression results 1) Ankle bone variables of width and length that correlated most

Wolverton, Steve

9

Asymptotic properties of Pearson's rank-variate correlation coefficient under contaminated Gaussian model.  

PubMed

This paper investigates the robustness properties of Pearson's rank-variate correlation coefficient (PRVCC) in scenarios where one channel is corrupted by impulsive noise and the other is impulsive noise-free. As shown in our previous work, these scenarios that frequently encountered in radar and/or sonar, can be well emulated by a particular bivariate contaminated Gaussian model (CGM). Under this CGM, we establish the asymptotic closed forms of the expectation and variance of PRVCC by means of the well known Delta method. To gain a deeper understanding, we also compare PRVCC with two other classical correlation coefficients, i.e., Spearman's rho (SR) and Kendall's tau (KT), in terms of the root mean squared error (RMSE). Monte Carlo simulations not only verify our theoretical findings, but also reveal the advantage of PRVCC by an example of estimating the time delay in the particular impulsive noise environment. PMID:25393286

Ma, Rubao; Xu, Weichao; Zhang, Yun; Ye, Zhongfu

2014-01-01

10

Asymptotic Properties of Pearson's Rank-Variate Correlation Coefficient under Contaminated Gaussian Model  

PubMed Central

This paper investigates the robustness properties of Pearson's rank-variate correlation coefficient (PRVCC) in scenarios where one channel is corrupted by impulsive noise and the other is impulsive noise-free. As shown in our previous work, these scenarios that frequently encountered in radar and/or sonar, can be well emulated by a particular bivariate contaminated Gaussian model (CGM). Under this CGM, we establish the asymptotic closed forms of the expectation and variance of PRVCC by means of the well known Delta method. To gain a deeper understanding, we also compare PRVCC with two other classical correlation coefficients, i.e., Spearman's rho (SR) and Kendall's tau (KT), in terms of the root mean squared error (RMSE). Monte Carlo simulations not only verify our theoretical findings, but also reveal the advantage of PRVCC by an example of estimating the time delay in the particular impulsive noise environment. PMID:25393286

Ma, Rubao; Xu, Weichao; Zhang, Yun; Ye, Zhongfu

2014-01-01

11

Pearson's Correlation between Three Variables; Using Students' Basic Knowledge of Geometry for an Exercise in Mathematical Statistics  

ERIC Educational Resources Information Center

When studying correlations, how do the three bivariate correlation coefficients between three variables relate? After transforming Pearson's correlation coefficient r into a Euclidean distance, undergraduate students can tackle this problem using their secondary school knowledge of geometry (Pythagoras' theorem and similarity of triangles).…

Vos, Pauline

2009-01-01

12

Correlational Analysis of Ordinal Data: From Pearson's "r" to Bayesian Polychoric Correlation  

ERIC Educational Resources Information Center

Correlational analyses are one of the most popular quantitative methods, yet also one of the mostly frequently misused methods in social and behavioral research, especially when analyzing ordinal data from Likert or other rating scales. Although several correlational analysis options have been developed for ordinal data, there seems to be a lack…

Choi, Jaehwa; Peters, Michelle; Mueller, Ralph O.

2010-01-01

13

An Improved Pearson's Correlation Proximity-Based Hierarchical Clustering for Mining Biological Association between Genes  

PubMed Central

Microarray gene expression datasets has concerned great awareness among molecular biologist, statisticians, and computer scientists. Data mining that extracts the hidden and usual information from datasets fails to identify the most significant biological associations between genes. A search made with heuristic for standard biological process measures only the gene expression level, threshold, and response time. Heuristic search identifies and mines the best biological solution, but the association process was not efficiently addressed. To monitor higher rate of expression levels between genes, a hierarchical clustering model was proposed, where the biological association between genes is measured simultaneously using proximity measure of improved Pearson's correlation (PCPHC). Additionally, the Seed Augment algorithm adopts average linkage methods on rows and columns in order to expand a seed PCPHC model into a maximal global PCPHC (GL-PCPHC) model and to identify association between the clusters. Moreover, a GL-PCPHC applies pattern growing method to mine the PCPHC patterns. Compared to existing gene expression analysis, the PCPHC model achieves better performance. Experimental evaluations are conducted for GL-PCPHC model with standard benchmark gene expression datasets extracted from UCI repository and GenBank database in terms of execution time, size of pattern, significance level, biological association efficiency, and pattern quality. PMID:25136661

Booma, P. M.; Prabhakaran, S.; Dhanalakshmi, R.

2014-01-01

14

Correcting Two-Sample "z" and "t" Tests for Correlation: An Alternative to One-Sample Tests on Difference Scores  

ERIC Educational Resources Information Center

In order to circumvent the influence of correlation in paired-samples and repeated measures experimental designs, researchers typically perform a one-sample Student "t" test on difference scores. That procedure entails some loss of power, because it employs N - 1 degrees of freedom instead of the 2N - 2 degrees of freedom of the…

Zimmerman, Donald W.

2012-01-01

15

The Use of Time Series Analysis and t Tests with Serially Correlated Data Tests.  

ERIC Educational Resources Information Center

Results of three methods of analysis applied to simulated autocorrelated data sets with an intervention point (varying in autocorrelation degree, variance of error term, and magnitude of intervention effect) are compared and presented. The three methods are: t tests; maximum likelihood Box-Jenkins (ARIMA); and Bayesian Box Jenkins. (Author/AEF)

Nicolich, Mark J.; Weinstein, Carol S.

1981-01-01

16

Karl Pearson  

Microsoft Academic Search

MR. G. UDNY YULE'S interesting obituary of Karl Pearson (NATURE, May 23, p. 856) does not offer ``the meed of some melodious tear'' to his efforts for the creation of a great University of London. ``K. P.'' collected his ephemeral contributions on this question in a small book, ``The New University of London'' (Fisher Unwin, 1892). Appendix C (p. 130)

T. Ll. Humberstone

1936-01-01

17

Paired t testsPaired t tests Paired (dependent) t-testPaired (dependent) t test  

E-print Network

Paired t testsPaired t tests #12;Paired (dependent) t-testPaired (dependent) t test · Compares test means from matched pairsCompares test means from matched pairs or two different samples from the same individualsindividuals ­ e.g., pretest & post test scores for the same group of students Ho: d = 0 d is thedifference

Wolverton, Steve

18

Group Heterogeneity and Pearson's "r."  

ERIC Educational Resources Information Center

Three factors that increase score variability yet can be associated with an increase, a decrease, or no change in Pearson's correlation coefficient (r) are discussed (restriction of range, errors of measurement, and linear transformations of data). The connection between changes in variability and r depends on how changes occur. (SLD)

Huck, Schuyler W.

1992-01-01

19

FRACTIONAL PEARSON DIFFUSIONS  

PubMed Central

Pearson diffusions are governed by diffusion equations with polynomial coefficients. Fractional Pearson diffusions are governed by the corresponding time-fractional diffusion equation. They are useful for modeling sub-diffusive phenomena, caused by particle sticking and trapping. This paper provides explicit strong solutions for fractional Pearson diffusions, using spectral methods. It also presents stochastic solutions, using a non-Markovian inverse stable time change. PMID:23626377

Leonenko, Nikolai N.; Meerschaert, Mark M.

2013-01-01

20

Pearson's meta-analysis 1 Pearson's meta-analysis revisited  

E-print Network

leads to something new that may be better revisited #12;Pearson's meta-analysis 3 Karl Pearson quote Stigler (2008) recounting Karl Pearson's amazing productivity includes this from Stouffer (1958): "YouPearson's meta-analysis 1 Pearson's meta-analysis revisited in a microarray context Art B. Owen

Owen, Art

21

Correlation  

NSDL National Science Digital Library

This chapter will discuss the concept of correlation , which is used in later chapters that will explain the concepts of validity and reliability. Here, the authors introduce the Pearson correlation coefficient, a statistic that is used with ratio

Christmann, Edwin P.; Badgett, John L.

2008-11-01

22

Pearson's Functions to Describe FSW Weld Geometry  

NASA Astrophysics Data System (ADS)

Friction stir welding (FSW) is a relatively new joining technique particularly for aluminium alloys that are difficult to fusion weld. In this study, the geometry of the weld has been investigated and modelled using Pearson's functions. It has been demonstrated that the Pearson's parameters (mean, standard deviation, skewness, kurtosis and geometric constant) can be used to characterize the weld geometry and the tensile strength of the weld assembly. Pearson's parameters and process parameters are strongly correlated allowing to define a control process procedure for FSW assemblies which make radiographic or ultrasonic controls unnecessary. Finally, an optimisation using a Generalized Gradient Method allows to determine the geometry of the weld which maximises the assembly tensile strength.

Lacombe, D.; Gutierrez-Orrantia, M. E.; Coupard, D.; Tcherniaeff, S.; Girot, F.

2011-01-01

23

Pearson's Functions to Describe FSW Weld Geometry  

SciTech Connect

Friction stir welding (FSW) is a relatively new joining technique particularly for aluminium alloys that are difficult to fusion weld. In this study, the geometry of the weld has been investigated and modelled using Pearson's functions. It has been demonstrated that the Pearson's parameters (mean, standard deviation, skewness, kurtosis and geometric constant) can be used to characterize the weld geometry and the tensile strength of the weld assembly. Pearson's parameters and process parameters are strongly correlated allowing to define a control process procedure for FSW assemblies which make radiographic or ultrasonic controls unnecessary. Finally, an optimisation using a Generalized Gradient Method allows to determine the geometry of the weld which maximises the assembly tensile strength.

Lacombe, D.; Coupard, D.; Tcherniaeff, S. [Arts et Metiers ParisTech, LAMEFIP, Esplanade des Arts et Metiers, 33405 Talence Cedex (France); Girot, F. [IKERBASQUE, Basque Foundation for Science, Bilbao (Spain); Gutierrez-Orrantia, M. E.

2011-01-17

24

Pearson and the patient.  

PubMed Central

This lecture covers some subjects of direct concern to the medical profession contained within the Pearson Report. Each injury group was examined by the Royal Commission, both here and abroad, particular attention being paid to the relationship between tort and social security. By consensus it was proposed that in the majority of fields no-fault compensations should be extended but that the tort system should continue to have a role. Recommendations were also put forward that no damages should be permitted for non-pecuniary loss during the first 3 months and that the full value of the social security benefits should be deductible from all tort damages. Damages for permanent injury or death should be index-linked periodic payments. A new no-fault compensation scheme for road accidents was described as well as a new disabled children's allowance of 4 pounds per week with a mobility allowance at the lower age of 2 years. Medical injury was examined carefully, but it was decided that negligence liability should continue unchanged, with the proviso that the no-fault compensation schemes in New Zealand and in Sweden should be followed. These two schemes have therefore been described in some detail. PMID:159014

Duthie, R. B.

1979-01-01

25

The Contributions of Karl Pearson  

Microsoft Academic Search

* A paper read in Atlantic City, September 11, 1957, at a joint meeting of the American Statistical Association and the Institute of Mathematical Statistics. The chief source of biographical information was the 170 page memoir by Egon S. Pearson, Karl Pearson, An Appreciation of Some Aspects of His Life and Works, Cambridge University Press, 1938. Quotation has also been

Helen M. Walker

1958-01-01

26

Karl Pearson and the professional middle class  

Microsoft Academic Search

Karl Pearson (1857–1936) is a figure of interest to historians of many areas. The historian of mathematical statistics knows the inventor of the product-moment correlation coefficient and the chi square test; the historian of philosophy knows the author of the Grammar of science; the historian of genetics knows the opponent of Mendelism; the political historian knows the ‘social-imperialist’ political thinker;

D. MacKenzie

1979-01-01

27

Single Sample t-Test  

NSDL National Science Digital Library

This page will perform a t-test for the significance of the difference between the observed mean of a sample and a hypothetical mean of the population from which the sample is randomly drawn. The user will be asked to specify the sample size as the page opens.

Lowry, Richard, 1940-

2008-09-05

28

Karl Pearson in Russian Contexts  

Microsoft Academic Search

The confluence of statistics and probability into mathematical statistics in the Russian Empire through the interaction, 1910-1917, of A.A. Chuprov and A.A. Markov was influenced by the writings of the English Biometric School, especially those of Karl Pearson. The appearance of the Russian-language exposition of Pearsonian ideas by E. E. Slutsky in 1912 was instrumental in this confluence. Slutsky's predecessors

Eugene Seneta

2009-01-01

29

Understanding Karl Pearson's Influence on Italian Statistics in the Early 20th Century  

Microsoft Academic Search

Karl Pearson's work strongly influenced the development of Italian statistics in the early 20th century. This paper reports some Italian contributions following Pearson's thought, which are probably less known outside Italy; for other Italian work, which was more successful internationally, just a brief description is given. Pearsonian topics are divided into three categories: curve systems, interpolation and correlation. For the

Claudio Giovanni Borroni

2009-01-01

30

Karl Pearson and the Origin of Kurtosis  

Microsoft Academic Search

Although the kurtosis index proposed by Karl Pearson in 1905 is introduced in statistical textbooks at all levels, the measure is not easily interpreted and has been a subject of considerable debate. In this study, the theoretical development of kurtosis is surveyed from a historical perspective of Pearson's work on evolution. It surprisingly emerges that there was no emphasis in

Anna M. Fiori; Michele Zenga

2009-01-01

31

SPSS Tutorial for t-tests.  

NSDL National Science Digital Library

This tutorial, created by Laura Little of the University of Washington, exposes students to conducting t-tests in SPSS. This html based tutorial provides extensive screen shots and two example data sets. Topics covered in the tutorial include one sample, paired and independent samples t-tests and conducting transformations (such as a difference) of the data.

Little, Laura

2009-03-11

32

Karl Pearson's meta-analysis revisited  

Microsoft Academic Search

This paper revisits a meta-analysis method proposed by Pearson [Biometrika 26 (1934) 425--442] and first used by David [Biometrika 26 (1934) 1--11]. It was thought to be inadmissible for over fifty years, dating back to a paper of Birnbaum [J. Amer. Statist. Assoc. 49 (1954) 559--574]. It turns out that the method Birnbaum analyzed is not the one that Pearson

Art B. Owen

2009-01-01

33

Impact of Karl Pearson's Work on Statistical Developments in India  

Microsoft Academic Search

Karl Pearson's work greatly inspired P. C. Mahalanobis's interest in statistics, who was at the centre of modern statistical developments in India. Mahalanobis learned statistics on his own, reading Pearson's articles and his journal, and encouraged others to study Pearson's papers. Pearson was a Honorary Fellow of the Indian Statistical Institute, which has been a leading statistical training and research

Tapan K. Nayak

2009-01-01

34

Karl Pearson's meta-analysis revisited Art B. Owen  

E-print Network

Karl Pearson's meta-analysis revisited Art B. Owen Department of Statistics Sequoia Hall 390 Serra: This paper revisits a meta-analysis method proposed by Pearson (1934) and first used by David (1933 that the method Birnbaum analyzed is not the one that Pearson proposed. We show that Pearson's proposal

Owen, Art

35

On the Intellectual Versatility of Karl Pearson  

Microsoft Academic Search

This paper displays the impressive versatility of Karl Pearson, focusing not only on his contributions to statistics and other quantitative disciplines but also on his research and publications in religion, politics, literary criticism, philosophy of science, Darwinism, biology, history, freethought, evolution, genetics, socialism, anthropology, eugenics, and emancipation of women. Being the chairman of a first class academic department and the

Richard H. Williams; Bruno D. Zumbo; Donald Ross; W. Zimmerman

36

The One-Sample t Test  

NSDL National Science Digital Library

This section, part of a larger site produced by the School of Psychology at the University of New England, focuses on "Common Statistical Tests" using an example on faculty publications to show users how to perform a one-sample t test. Additionally, there is a discussion that includes one-tailed and two-tailed tests.

Price, Ian

2009-01-13

37

Student's t-Test for Independent Samples  

NSDL National Science Digital Library

This tutorial, created by Thomas W. MacFarland of Nova Southeastern University, explains the theory and use of Student's t-test and demonstrates it with an example on final exam scores. Data sets are provided in both SPSS and Minitab code. This is a great resource, or even lesson plan, for anyone interested in a more in-depth look at statistical testing.

MacFarland, Thomas W.

38

Student's t-Test for Matched Pairs  

NSDL National Science Digital Library

This tutorial, created by Thomas W. McFarland of Nova Southeastern University, explains the theory and use of Student's t-test for matched pairs and demonstrates it with an example on project quality. Data sets are provided in both SPSS and Minitab code. This is a nice resource for both students and teachers. It can be used for a more in-depth look at statistical testing.

MacFarland, Thomas W.

39

Letters between Karl Pearson and Vito Volterra  

Microsoft Academic Search

\\u000a Karl Pearson was born in London on 27 March 1857. He spent seven years at University College School, London, from which he\\u000a withdrew for one year in 1873 owing to illness, continuing his studies with a private tutor. In 1875 he was admitted to King’s\\u000a College, Cambridge, where he studied mathematics with teachers of the calibre of Edward John Routh

Giorgio Israel; Ana Millán Gasca

40

Karl Pearson's Influence in the United States  

Microsoft Academic Search

Karl Pearson, the founder of mathematical statistics, was the leading statistical researcher from the 1890s up to about 1920. His interests were wide-ranging and so his impact on statistics in the United States was also wide-ranging. Many American researchers came to University College London to study with him. Others studied his work from afar. In the United States, Pearsonian statistics

David R. Bellhouse

2009-01-01

41

Correlations, Contrasts, and Conceptual Clarity.  

ERIC Educational Resources Information Center

This paper discusses the Pearson product moment correlation (K. Pearson, 1986). Although this correlational metric is old, published in the 19th century, this paper suggests that it remains the most nearly universally applicable index of effect size. It is difficult to imagine a situation in which a Pearson "r" or its equivalent could not be used…

Rosenthal, Robert

42

James Pearson Duffy Department of Art and Art History James Pearson Duffy Department of Art and Art History  

E-print Network

1 James Pearson Duffy Department of Art and Art History James Pearson Duffy Department of Art and Art History 150 Art Building Detroit, Michigan 48202 Telephone: (313) 577-2980 Fax: (313) 577: (313) 577-2980 Designing the Wild and Cultivating the City The James Pearson Duffy Department of Art

Berdichevsky, Victor

43

The Pearson-Readhead Survey from Space  

NASA Technical Reports Server (NTRS)

The VSOP Space VLBI mission uses the HALCA spacecraft, launched from Japan in February 1997, in conjunction with ground radio observatories around the world to create a high resolution radio-wave length imaging facility. We are using this unique facility to observe a complete sample of Pearson-Readhead Survey sources at 4.8 GHz to determine core brightness temperatures and pc-scale jet properties. The Pearson-Readhead sample has been used for extensive ground-based VLBI survey studies. This sample is ideal for a VSOP survey because the sources are strong, the VSOP u-v coverages are especially good above +350 declination, and multi-epoch ground-based VLBI data and other existing supporting data on these sources exceeds that of any other possible sample. We have chosen to observe a complete subset of this sample that is most likely to show fringes on space-earth baselines. To date we have imaged a majority of the 31 sources in our sample. In addition, we are obtaining matched- resolution 15 GHz observations using the VLBA at epochs close in time to the space VLBI observations to investigate the spectral indices of the source components at high resolution. We gratefully acknowledge the VSOP Project, which is led by the Japanese Institute of Space and Astronautical Science in cooperation with many organizations and radio telescopes around the world. This research was performed in part at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA.

Preston, R. A.; Tingay, S. J.; Jones, D. L.; Lister, M.; Piner, G.; Murphy, D. W.; Meier, D. L.; Pearson, T. J.; Readhead, A. C. S.; Hirabayashi, H.; Kobayashi, H.; Inoue, M.

1988-01-01

44

Sensitivity analysis of Welch's t-test  

NASA Astrophysics Data System (ADS)

Welch t-test is the parametric test for comparing means between two independent groups without assuming equal population variances. This statistic is robust for testing the mean equality when homogeneity assumption is not satisfied, but Welch test is not always robust. When multiple problems such as the distribution is non-normal, variance is heterogeneous and unequal size of groups occur simultaneously, the Type I error will inflate. In this study, various conditions such as sample sizes, type of distributions and unequal group variances were manipulated to investigate on the non robust conditions of Welch test. The Type I error rates and power of the test for different design specifications were obtained and compared. The results indicated that this test did not perform well under non-normal distributions especially when group sizes and unequal group variances are inversely associated or negatively paired. The estimated Type I error inflated as the power of the test improved.

Ahad, Nor Aishah; Yahaya, Sharipah Soaad Syed

2014-07-01

45

2015 Pearson Education, Inc. Chapter 6 Atmospheric and Oceanic  

E-print Network

;© 2015 Pearson Education, Inc. Air Pressure · Atmospheric pressure is the force per unit area exerted. Atmospheric Pressure Profile #12;© 2015 Pearson Education, Inc. Measure Air Pressure--Mercury Barometer · Seal Education, Inc. Driving Forces Within the Atmosphere · Gravity · Pressure gradient force · Coriolis force

Pan, Feifei

46

2015 Pearson Education, Inc. Chapter 3 Earth's Modern Atmosphere  

E-print Network

© 2015 Pearson Education, Inc. Chapter 3 Earth's Modern Atmosphere #12;© 2015 Pearson Education, Inc. · Draw a diagram showing atmospheric structure based on three criteria for analysis--composition, temperature, and function. · List and describe the components of the modern atmosphere, giving their relative

Pan, Feifei

47

2005 Pearson Education Inc., publishing as Addison-Wesley  

E-print Network

© 2005 Pearson Education Inc., publishing as Addison-Wesley The Big Bang Theory & Expansion is the unfolding of all space since the big bang, i.e. there is no edge. ·We are limited in our view see back... Radiation signature from 300,000 years after the Big Bang #12;© 2005 Pearson Education

Shirley, Yancy

48

Karl Pearson and the Scandinavian School of Statistics  

Microsoft Academic Search

The relationship between Karl Pearson and the Scandinavian statisticians was more of a competitive than a collaborative nature. We describe the leading statisticians and stochasticists of the Scandinavian school, and relate some of their work to the work of Pearson. Copyright (c) 2009 The Authors. Journal compilation (c) 2009 International Statistical Institute.

Peter Guttorp; Georg Lindgren

2009-01-01

49

On the characteristic function of Pearson type IV distributions  

Microsoft Academic Search

Using an identity of Stein, Approximate computation of expectations, this article gives an exact expression for the characteristic function of Pearson type IV distributions in terms of confluent hypergeometric functions.

Wei-Liem Loh

2004-01-01

50

Genetics Home Reference: Pearson marrow-pancreas syndrome  

MedlinePLUS

Pearson marrow-pancreas syndrome Mitochondrial DNA Related Condition(s) References Quick links to this topic MedlinePlus Health information Additional NIH Resources National Institutes of Health Educational resources Information ...

51

18. TYPE F, BUILDING #516732 PEARSON ROAD, INTERIOR, THIRD FLOOR, ...  

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

18. TYPE F, BUILDING #516-732 PEARSON ROAD, INTERIOR, THIRD FLOOR, BEDROOM, NORTHWEST VIEW. - Wright-Patterson Air Force Base, Brick Officers' Quarters, Types E & F, Area A, Dayton, Montgomery County, OH

52

DEDICATED TO PROFESSOR V. PAPATHANASIOU Integrated Pearson family and orthogonality of the  

E-print Network

of distributions; Derivatives of orthogonal polynomials; Rodrigues polynomials. 1 Introduction Karl Pearson (1895DEDICATED TO PROFESSOR V. PAPATHANASIOU Integrated Pearson family and orthogonality of the Rodrigues polynomials: A review including new results and an alternative classification of the Pearson

Papadatos, Nickos

53

DEDICATED TO PROFESSOR V. PAPATHANASIOU Integrated Pearson family and orthogonality of the  

E-print Network

; Derivatives of orthogonal polynomials; Rodrigues polynomials. 1 Introduction Karl Pearson (1895DEDICATED TO PROFESSOR V. PAPATHANASIOU Integrated Pearson family and orthogonality of the Rodrigues polynomials: A review including new results and an alternative classification of the Pearson

Papadatos, Nickos

54

On Correlation and Causation David A. Bessler  

E-print Network

and have been obtained via Google Image. Karl Pearson (left) and Francis Galton (right) 1 #12;Correlation. This measure was invented by Galton in the 19th century and used extensively by Pearson in the early 20th from anthropological data," Proceedings of the Royal Society of London 45:135-45. See as well, Pearson

McCarl, Bruce A.

55

Karl Pearson and eugenics: personal opinions and scientific rigor.  

PubMed

The influence of personal opinions and biases on scientific conclusions is a threat to the advancement of knowledge. Expertise and experience does not render one immune to this temptation. In this work, one of the founding fathers of statistics, Karl Pearson, is used as an illustration of how even the most talented among us can produce misleading results when inferences are made without caution or reference to potential bias and other analysis limitations. A study performed by Pearson on British Jewish schoolchildren is examined in light of ethical and professional statistical practice. The methodology used and inferences made by Pearson and his coauthor are sometimes questionable and offer insight into how Pearson's support of eugenics and his own British nationalism could have potentially influenced his often careless and far-fetched inferences. A short background into Pearson's work and beliefs is provided, along with an in-depth examination of the authors' overall experimental design and statistical practices. In addition, portions of the study regarding intelligence and tuberculosis are discussed in more detail, along with historical reactions to their work. PMID:23179067

Delzell, Darcie A P; Poliak, Cathy D

2013-09-01

56

ON PEARSON-VERIFICATION AND THE CHI-SQUARE TEST JOAKIM EKSTROM  

E-print Network

ON PEARSON-VERIFICATION AND THE CHI-SQUARE TEST JOAKIM EKSTR¨OM Abstract. Karl Pearson's seminal empirical observation. 1 #12;2 1. Introduction Karl Pearson was a man who took on a mission to rectify has likely in various ways effected the scientific community negatively. Karl Pearson would

California at Los Angeles, University of

57

Chapter 12 The Dynamic Planet 2015 Pearson Education, Inc.  

E-print Network

, Landforms, Weathering, Erosion, Oceans, Glaciers). Two Broad Earth Systems #12;© 2015 Pearson Education, Inc is not to scale. Half-life, the decay-rate, is the time required for one-half of the unstable atoms in a rock scale, characteristic of postglacial conditions since the retreat of the continental glaciers, about 11

Pan, Feifei

58

Chapter 9 Water Resources 2015 Pearson Education, Inc.  

E-print Network

Evapotranspiration (PET) · Potential evapotranspiration (PET) is the amount of water that would evaporate, Inc. Potential Evapotranspiration (PET) · Potential evapotranspiration (PET) is the amount of waterChapter 9 Water Resources #12;© 2015 Pearson Education, Inc. Learning Objectives · Describe

Pan, Feifei

59

2005 Pearson Education Inc., publishing as Addison-Wesley  

E-print Network

© 2005 Pearson Education Inc., publishing as Addison-Wesley The Big Bang Theory & Expansion of thousands of big bang photons in every breath you take: the big bang is all around us. It is a theory space since the big bang, i.e. there is no edge. ·We are limited in our view by the time it takes

Shirley, Yancy

60

2015 Pearson Education, Inc. Chapter 4 Atmosphere and Surface Energy  

E-print Network

. · Explain the greenhouse concept as it applies to Earth. · Explain four types of heat transfer: radiation flux, and ground heat flux. · Plot typical daily radiation and temperature curves for Earth's surface delays transfer of heat from Earth into space. #12;© 2015 Pearson Education, Inc. Energy Effects of Cloud

Pan, Feifei

61

Karl Pearson's Theoretical Errors and the Advances They Inspired  

Microsoft Academic Search

Karl Pearson played an enormous role in determining the content and organization of statistical research in his day, through his research, his teaching, his establishment of laboratories, and his initiation of a vast publishing program. His technical contributions had initially and continue today to have a profound impact upon the work of both applied and theoretical statisticians, partly through their

Stephen M. Stigler

2008-01-01

62

The Epistemology of Natural Science and Mr. Karl Pearson  

Microsoft Academic Search

ONLY a few days ago I happened to see the review of my ``Erkenntnistheoretische Grundzüge der Naturwissenschaften'' (Leipzig, 1896) in NATURE of November 5, 1896. I too highly esteem English science and literature to follow Mr. Karl Pearson in the department of his ``familiar ideas'' I shall confine myself to showing how little my reviewer has succeeded in rendering my

Paul Volkmann

1897-01-01

63

Quadrupolar magic angle spinning NMR spectra fitted using the Pearson IV function.  

PubMed

The Pearson IV function was used to fit the asymmetric solid-state (27)Al NMR spectra of alumina based catalysts. A high convergence (correlation coefficient is no less than 0.997) between experimental and simulated spectra was achieved. The decomposition of the (27)Al NMR spectra of zinc/aluminum mixed oxides with different Zn/Al molar ratio revealed an increased fraction (6-9%) of pentacoordinated aluminum atoms in these oxides as compared to ?-Al2O3. As the Zn/Al ratio is raised, the fraction of [AlO6] octahedral units decreases, while the fraction of [AlO4] tetrahedra increases. PMID:25454293

Mironenko, Roman M; Belskaya, Olga B; Talsi, Valentin P; Likholobov, Vladimir A

2014-01-01

64

Research Methods Knowledge Base : The t-Test  

NSDL National Science Digital Library

This particular textbook lesson, presented by Cornell University's Research Methods Knowledge Base, addresses the independent t-test. It presents to the user how to compute the t statistic and then how to interpret the results. The site uses graphs and charts along with the text to enhance the presentation. Overall, this is a useful resource for any mathematics classroom.

Trochim, William M.

2008-12-26

65

Spatial trends in Pearson Type III statistical parameters  

USGS Publications Warehouse

Spatial trends in the statistical parameters (mean, standard deviation, and skewness coefficient) of a Pearson Type III distribution of the logarithms of annual flood peaks for small rural basins (less than 90 km2) are delineated using a climate factor CT, (T=2-, 25-, and 100-yr recurrence intervals), which quantifies the effects of long-term climatic data (rainfall and pan evaporation) on observed T-yr floods. Maps showing trends in average parameter values demonstrate the geographically varying influence of climate on the magnitude of Pearson Type III statistical parameters. The spatial trends in variability of the parameter values characterize the sensitivity of statistical parameters to the interaction of basin-runoff characteristics (hydrology) and climate. -from Authors

Lichty, R.W.; Karlinger, M.R.

1995-01-01

66

2015 Pearson Education, Inc. Chapter 5 Global Temperatures  

E-print Network

point of water at 212ºF · Celsius (°C) ­ Ice melting point at 0°C, boiling point of water at sea level and Heat Transfer #12;© 2015 Pearson Education, Inc. · Fahrenheit (°F) ­ Ice melting point at 32°F, boiling of land versus water that produce continental effects and marine effects on temperatures, and utilize

Pan, Feifei

67

2005 Pearson Education Inc., publishing as Addison-Wesley  

E-print Network

of thousands of big bang photons in every breath you take: the big bang is all around us. It is a theory of the Big Bang #12;#12;© 2005 Pearson Education Inc., publishing as Addison-Wesley #12;Growth of large. · In the scale model, a human life is about 2 tenths of a second! #12;Jan 1st midnight Big Bang #12;Jan 1st

Shirley, Yancy

68

Sample size determination for a t test given a t value from a previous study: A FORTRAN 77 program.  

PubMed

When uncertain about the magnitude of an effect, researchers commonly substitute in the standard sample-size-determination formula an estimate of effect size derived from a previous experiment. A problem with this approach is that the traditional sample-size-determination formula was not designed to deal with the uncertainty inherent in an effect-size estimate. Consequently, estimate-substitution in the traditional sample-size-determination formula can lead to a substantial loss of power. A method of sample-size determination designed to handle uncertainty in effect-size estimates is described. The procedure uses the t value and sample size from a previous study, which might be a pilot study or a related study in the same area, to establish a distribution of probable effect sizes. The sample size to be employed in the new study is that which supplies an expected power of the desired amount over the distribution of probable effect sizes. A FORTRAN 77 program is presented that permits swift calculation of sample size for a variety of t tests, including independent t tests, related t tests, t tests of correlation coefficients, and t tests of multiple regression b coefficients. PMID:11816459

Gillett, R

2001-11-01

69

James Pearson Duffy Department of Art and Art History Wayne State University  

E-print Network

James Pearson Duffy Department of Art and Art History Wayne State University Duffy Department of Art and Art History along with community arts organizations Pearson Duffy Department of Art and Art History is a division of Wayne State

Berdichevsky, Victor

70

James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY  

E-print Network

1 James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY James Pearson Duffy Department of Art and Art History 150 Art Building Detroit, Michigan 48202 Telephone: (313) 577-2423 Fax (tpyrzewski@wayne.edu) The James Pearson Duffy Department of Art and Art History's Art Department Gallery

Cinabro, David

71

James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY  

E-print Network

1 James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY James Pearson Duffy Department of Art and Art History 150 Art Building Detroit, Michigan 48202 Telephone: (313) 5770770 Fax@wayne.edu) The James Pearson Duffy Department of Art and Art History's Art Department Gallery is pleased to present

Berdichevsky, Victor

72

James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY  

E-print Network

1 James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY James Pearson Duffy Department of Art and Art History 150 Art Building Detroit, Michigan 48202 Telephone: (313) 993-7813 Fax@wayne.edu) at (313) 993-7813 The James Pearson Duffy Department of Art and Art History's Art Department Gallery

Berdichevsky, Victor

73

James Pearson Duffy Department of Art and Art History Elaine L. Jacob Gallery  

E-print Network

1 James Pearson Duffy Department of Art and Art History Elaine L. Jacob Gallery 480 W. Hancock (tpyrzewski@wayne.edu) The James Pearson Duffy Department of Art and Art History's Elaine L. Jacob Gallery by Wayne State University's James Pearson Duffy Department of Art and Art History from October 3 through

Berdichevsky, Victor

74

Karl Pearson and R. A. Fisher on Statistical Tests: A 1935 Exchange from Nature  

Microsoft Academic Search

In 1935, a letter to Nature criticizing the logic of statistical tests provoked published responses from Karl Pearson and R. A. Fisher. Their letters illustrate the attitudes of the two men toward the hypothesis-testing problem soon after the Neyman-Pearson formulation and shortly before Karl Pearson's death.

Henry F. Inman

1994-01-01

75

Studies in the history of probability and statistics, L: Karl Pearson and the Rule of Three  

Microsoft Academic Search

Karl Pearson's role in the transformation that took the 19th century statistics of Laplace and Gauss into the modern era of 20th century multivariate analysis is examined from a new point of view. By viewing Pearson's work in the context of a motto he adopted from Charles Darwin, a philosophical theme is identified in Pearson's statistical work, and his three

Stephen M. Stigler

2012-01-01

76

TUFTS UNIVERSITY Eliot-Pearson Department of Child Study and Human Development  

E-print Network

pertinent to the longitudinal study of child or adolescent development is desired. Eliot-Pearson is knownTUFTS UNIVERSITY Eliot-Pearson Department of Child Study and Human Development ASSISTANT PROFESSOR POSITION IN DEVELOPMENTAL METHODOLOGY THE ELIOT-PEARSON DEPARTMENT OF CHILD STUDY AND HUMAN DEVELOPMENT

Dennett, Daniel

77

Correlation  

Microsoft Academic Search

Reviews 7 studies in the area of interpretation of correlation from the psychological point of view. The limitations and meanings of correlation methods have also been given. The statistical methods of calculating correlation, as given by 8 psychologists have been reported. Presents 22 reports, given by various psychologists, who have evaluated the tests using various correlation methods. Six studies were

James Burt Miner

1919-01-01

78

Correlation of Masseter Muscle Thickness and Intermolar Width - An Ultrasonography Study  

PubMed Central

Background: To determine the association between the thickness of masseter muscle and the maxillary dental arch width. To explore the influence of gender on masseter muscle thickness. Materials & methods: Seventy subjects (35 females and 35 males) of age 18 to 25 years were selected for the study based on class I molar relationship. The masseter muscle thickness of the right and left sides in every subject were found out through ultrasound scanning of the muscle, in both relaxed and clenched states. The maxillary dental arch width was measured on the study model with an electronic caliper. Student t test, Pearson’s Correlation Coefficient was performed to assess the sample. Results: Masseter Muscle Thickness showed a positive correlation with Maxillary Dental Arch Width r ?0.74. The masseter muscle thickness is greater in male subjects in both relaxed (0.001

Correlation of Masseter Muscle Thickness and Intermolar Width - An Ultrasonography Study. J Int Oral Health 2013; 5(2):28-34. PMID:24155588

Tircoveluri, Saritha; Singh, Johar Rajvinder; Rayapudi, Naveen; Karra, Arjun; Begum, Mohammadi; Challa, Padmalatha

2013-01-01

79

Thirteen Ways to Look at the Correlation Coefficient  

Microsoft Academic Search

In 1885, Sir Francis Galton first defined the term “regression” and completed the theory of bivariate correlation. A decade later, Karl Pearson developed the index that we still use to measure correlation, Pearson's r. Our article is written in recognition of the 100th anniversary of Galton's first discussion of regression and correlation. We begin with a brief history. Then we

Joseph Lee Rodgers; W. Alan Nicewander

1988-01-01

80

The power of a paired t-test with a covariate.  

PubMed

Many researchers employ the paired t-test to evaluate the mean difference between matched data points. Unfortunately, in many cases this test in inefficient. This paper reviews how to increase the precision of this test through using the mean centered independent variable x, which is familiar to researchers that use analysis of covariance (ANCOVA). We add to the literature by demonstrating how to employ these gains in efficiency as a factor for use in finding the statistical power of the test. The key parameters for this factor are the correlation between the two measures and the variance ratio of the dependent measure on the predictor. The paper then demonstrates how to compute the gains in efficiency a priori to amend the power computations for the traditional paired t-test. We include an example analysis from a recent intervention, Families Preparing the New Generation (Familias Preparando la Nueva Generación). Finally, we conclude with an analysis of extant data to derive reasonable parameter values. PMID:25592936

Hedberg, E C; Ayers, Stephanie

2015-03-01

81

ART DEPARTMENT GALLERY James Pearson Duffy Department of Art and Art History  

E-print Network

1 ART DEPARTMENT GALLERY James Pearson Duffy Department of Art and Art History 5400 Reuther Mall, 150 Art Building Detroit, Michigan 48202 Telephone: (313) 577-0770 Fax: (313) 577-8935 FOR IMMEDIATE. Pyrzewski (tpyrzewski@wayne.edu) The James Pearson Duffy Department of Art and Art History's Art Department

Cinabro, David

82

James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY  

E-print Network

1 James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY James Pearson Duffy Department of Art and Art History 150 Art Building Detroit, Michigan 48202 Telephone: (313) 993-7813 Fax of Art and Art History's Art Department Gallery is pleased to present 2011 WSU Faculty Exhibition Faculty

Berdichevsky, Victor

83

James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY  

E-print Network

1 James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY James Pearson Duffy Department of Art and Art History 150 Art Building Detroit, Michigan 48202 Telephone: (313) 993-7813 Fax Department of Art and Art History's Art Department Gallery is pleased to present Tri-County High School

Berdichevsky, Victor

84

James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY  

E-print Network

1 James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY James Pearson Duffy Department of Art and Art History 150 Art Building Detroit, Michigan 48202 Telephone: (313) 993-7813 Fax Duffy Department of Art and Art History's Art Department Gallery is pleased to present 2012 WSU

Berdichevsky, Victor

85

James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY  

E-print Network

James Pearson Duffy Department of Art and Art History ART DEPARTMENT GALLERY James Pearson Duffy Department of Art and Art History 150 Art Building Detroit, Michigan 48202 Telephone: (313) 993-7813 Fax of Art and Art History is a division of Wayne State's College of Fine, Performing and Communication Arts

Berdichevsky, Victor

86

Karl Pearson-The Scientific Life in a Statistical Age by Theodore M. Porter: A Review  

Microsoft Academic Search

Porter presents an excellent account of the young Karl Pearson and his extraordinarily varied activities. These ranged from the Cambridge Mathematical Tripos Exams to German history and folklore, and included free thought, socialism, the woman's question, and the law. Returning to science, Pearson produced the famous \\

Herbert A. David

2009-01-01

87

Karl pearson's mathematization of inheritance: From ancestral heredity to Mendelian genetics (1895–1909)  

Microsoft Academic Search

Long-standing claims have been made for nearly the entire twentieth century that the biometrician, Karl Pearson, and his colleague, W. F. R. Weldon, rejected Mendelism as a theory of inheritance. It is shown that at the end of the nineteenth century Pearson considered various theories of inheritance (including Francis Galton's law of ancestral heredity for characters underpinned by continuous variation),

M. Eileen Magnello

1998-01-01

88

Valuing Stocks Copyright 2014 Pearson Education, Inc. All rights reserved. 9-2  

E-print Network

Chapter 9 Valuing Stocks #12;Copyright ©2014 Pearson Education, Inc. All rights reserved. 9, and Stock Prices #12;Copyright ©2014 Pearson Education, Inc. All rights reserved. 9-3 Learning Objectives 1. Describe, in words, the Law of One Price value for a common stock, including the discount rate that should

Schubart, Christoph

89

Valuing Bonds Copyright 2014 Pearson Education, Inc. All rights reserved. 6-2  

E-print Network

Chapter 6 Valuing Bonds #12;Copyright ©2014 Pearson Education, Inc. All rights reserved. 6 Curve and Bond Arbitrage 6.4 Corporate Bonds 6.5 Sovereign Bonds #12;Copyright ©2014 Pearson Education and zero-coupon bonds, and calculate the value for each type of bond. 2. Calculate the yield to maturity

Schubart, Christoph

90

Correlation  

NSDL National Science Digital Library

Three hypothetical rock sections along an East-West transect are provided. Students correlate the three sections using the biostratigraphy of planktic forams (as a proxy for age), benthic forams (as a proxy of depth), and lithology (as a proxy of environment). Students are asked to provide an interpretation of the history of this depositional basin. An ash bed of known age is added and students are asked to determine if this new information affects their interpretation. Finally, an interesting lithologic feature is added, and students are asked to provide a geological explanation.

Pennilyn Higgins

91

A new correlation coefficient for bivariate time-series data  

NASA Astrophysics Data System (ADS)

The correlation in time series has received considerable attention in the literature. Its use has attained an important role in the social sciences and finance. For example, pair trading in finance is concerned with the correlation between stock prices, returns, etc. In general, Pearson’s correlation coefficient is employed in these areas although it has many underlying assumptions which restrict its use. Here, we introduce a new correlation coefficient which takes into account the lag difference of data points. We investigate the properties of this new correlation coefficient. We demonstrate that it is more appropriate for showing the direction of the covariation of the two variables over time. We also compare the performance of the new correlation coefficient with Pearson’s correlation coefficient and Detrended Cross-Correlation Analysis (DCCA) via simulated examples.

Erdem, Orhan; Ceyhan, Elvan; Varli, Yusuf

2014-11-01

92

Mitochondrial DNA deletion in a patient with combined features of Leigh and Pearson syndromes  

SciTech Connect

We describe a heteroplasmic 4237 bp mitochondrial DNA (mtDNA) deletion in an 11 year old girl who has suffered from progressive illness since birth. She has some features of Leigh syndrome (global developmental delay with regression, brainstem dysfunction and lactic acidosis), together with other features suggestive of Pearson syndrome (history of pancytopenia and failure to thrive). The deletion was present at a level greater than 50% in skeletal muscle, but barely detectable in skin fibroblasts following Southern blot analysis, and only observed in blood following PCR analysis. The deletion spanned nt 9498 to nt 13734, and was flanked by a 12 bp direct repeat. Genes for cytochrome c oxidase subunit III, NADH dehydrogenase subunits 3, 4L, 4 and 5, and tRNAs for glycine, arginine, histidine, serine({sup AGY}) and leucine({sup CUN}) were deleted. Southern blotting also revealed an altered Apa I restriction site which was shown by sequence analysis to be caused by G{r_arrow}A nucleotide substitution at nt 1462 in the 12S rRNA gene. This was presumed to be a polymorphism. No abnormalities of mitochondrial ultrastructure, distribution or of respiratory chain enzyme complexes I-IV in skeletal muscle were observed. Mitochondrial disorders with clinical features overlapping more than one syndrome have been reported previously. This case further demonstrates the difficulty in correlating observed clinical features with a specific mitochondrial DNA mutation.

Blok, R.B.; Thorburn, D.R.; Danks, D.M. [Royal Children`s Hospital, Melbourne (Australia)] [and others

1994-09-01

93

Psychological Statistics: Correlation  

NSDL National Science Digital Library

This page, created by Mark Plonsky of the University of Wisconsin - Stevens Point, gives a description of correlation, Pearson's r, Spearman's rho. There are some scatterplots illustrating the different values of r. This is a nice introduction to how statistics can be applied to many different disciplines.

Plonsky, Mark

2009-11-19

94

The Evolution of Pearsons Correlation Coefficient/Exploring Relationships between Two Quantitative Variables  

NSDL National Science Digital Library

The evolution of ideas is often ignored in the teaching of statistics. It is important to show students how definitions and formulas evolve. This activity describes a fairly straightforward activity of how measures of association can evolve.

Gary Kader

95

Personality Correlates of Privacy  

Microsoft Academic Search

Personality correlates of privacy preferences for 70 undergraduates were obtained through use of a semantic differential measure of self-esteem and other-esteem and an inventory which assessed cycloid disposition, rhathymia, thinking introversion, and cooperativeness. Pearson product moment correlations indicated that privacy choices tended to be associated with personality characteristics. Subjects low in self-esteem were more likely to be reserved and to

Darhl M. Pedersen

1982-01-01

96

Measuring correlations between non-stationary series with DCCA coefficient  

NASA Astrophysics Data System (ADS)

In this short report, we investigate the ability of the DCCA coefficient to measure correlation level between non-stationary series. Based on a wide Monte Carlo simulation study, we show that the DCCA coefficient can estimate the correlation coefficient accurately regardless the strength of non-stationarity (measured by the fractional differencing parameter d). For a comparison, we also report the results for the standard Pearson correlation coefficient. The DCCA coefficient dominates the Pearson coefficient for non-stationary series.

Kristoufek, Ladislav

2014-05-01

97

Comparison of the Mahalanobis distance and Pearson's ?² statistic as measures of similarity of isotope patterns.  

PubMed

To extract a genuine peptide signal from a mass spectrum, an observed series of peaks at a particular mass can be compared with the isotope distribution expected for a peptide of that mass. To decide whether the observed series of peaks is similar to the isotope distribution, a similarity measure is needed. In this short communication, we investigate whether the Mahalanobis distance could be an alternative measure for the commonly employed Pearson's ?(2) statistic. We evaluate the performance of the two measures by using a controlled MALDI-TOF experiment. The results indicate that Pearson's ?(2) statistic has better discriminatory performance than the Mahalanobis distance and is a more robust measure. PMID:24249044

Zamanzad Ghavidel, Fatemeh; Claesen, Jürgen; Burzykowski, Tomasz; Valkenborg, Dirk

2014-02-01

98

Metaphysics and population genetics: Karl Pearson and the background to Fisher's multi-factorial theory of inheritance  

Microsoft Academic Search

This paper traces the background to R. A. Fisher's multi-factorial theory of inheritance. It is argued that the traditional account is incomplete, and that Karl Pearson's well-known pre-Fisherian objections to the theory were in fact overcome by Pearson himself. It is further argued that Pearson's stated reasons for not accepting his own achievement has to be seen as a rationalization,

B. Norton

1975-01-01

99

Philosophy of Science Association In Defense of the Neyman-Pearson Theory of Confidence Intervals  

E-print Network

as discrediting the Neyman Pearson (NP) theory of statistical inference. The statistical methods of NP theory & State University In Philosophical Problems of Statistical Inference, Seidenfeld argues that the Neyman are used widely in the sciences, more than any other theory of inference; and should these methods prove

Mayo, Deborah

100

WHO IS MY ADVISOR? JAMES PEARSON DUFFY DEPARTMENT OF ART and ART HISTORY  

E-print Network

WHO IS MY ADVISOR? JAMES PEARSON DUFFY DEPARTMENT OF ART and ART HISTORY MAJORS: Art (fine arts and design), Art History, Fashion Design and Merchandising For students with last names starting A ­ M Ryan OF COMMUNICATION MAJORS: Film Arts and Media Studies, Journalism Angela Windfield angela

Cinabro, David

101

Wayne State University James Pearson Duffy Department of Art and Art History  

E-print Network

Wayne State University James Pearson Duffy Department of Art and Art History Art Department Gallery of Art and Art History is a division of Wayne State's College of Fine, Performing and Communication Arts 150 Art Building 5400 Reuther Mall Detroit, MI 48202 Telephone: (313) 577-2423 Fax: (313) 577

Cinabro, David

102

A New Way to Teach (or Compute) Pearson's "r" without Reliance on Cross-Products  

ERIC Educational Resources Information Center

Many students have difficulty seeing the conceptual link between bivariate data displayed in a scatterplot and the statistical summary of the relationship, "r." This article shows how to teach (and compute) "r" such that each datum's direct and indirect influences are made apparent and used in a new formula for calculating Pearson's "r."

Huck, Schuyler W.; Ren, Bixiang; Yang, Hongwei

2007-01-01

103

A Psychometric Measurement Model for Adult English Language Learners: Pearson Test of English Academic  

ERIC Educational Resources Information Center

The aim of this study was to apply Rasch modeling to an examination of the psychometric properties of the "Pearson Test of English Academic" (PTE Academic). Analyzed were 140 test-takers' scores derived from the PTE Academic database. The mean age of the participants was 26.45 (SD = 5.82), ranging from 17 to 46. Conformity of the participants'…

Pae, Hye K.

2012-01-01

104

Racial Harmony & Heroes: A Content Analysis of the Pearson Reading Program "Good Habits, Great Readers"  

ERIC Educational Resources Information Center

Multicultural education is a term with a variety of definitions growing from a number of different disciplines. These authors conducted a content analysis of the Pearson reading program "Good Habits, Great Readers" for grades four and five. The qualitative approach of content analysis allowed researchers to examine text "through the…

Tosolt, Brandelyn; Love, Bettina L.

2011-01-01

105

Karl Pearson's mathematization of inheritance: from ancestral heredity to Mendelian genetics (1895-1909).  

PubMed

Long-standing claims have been made for nearly the entire twentieth century that the biometrician, Karl Pearson, and colleague, W. F. R. Weldon, rejected Mendelism as a theory of inheritance. It is shown that at the end of the nineteenth century Pearson considered various theories of inheritance (including Francis Galton's law of ancestral heredity for characters underpinned by continuous variation), and by 1904 he 'accepted the fundamental idea of Mendel' as a theory of inheritance for discontinuous variation. Moreover, in 1909, he suggested a synthesis of biometry and Mendelism. Despite the many attempts made by a number of geneticists (including R. A. Fisher in 1936) to use Pearson's chi-square (X2, P) goodness-of-fit test on Mendel's data, which produced results that were 'too good to be true', Weldon reached the same conclusion in 1902, but his results were never acknowledged. The geneticist and arch-rival of the biometricians, Williams Bateson, was instead exceptionally critical of this work and interpreted this as Weldon's rejection of Mendelism. Whilst scholarship on Mendel, by historians of science in the last 18 years, has led to a balanced perspective of Mendel, it is suggested that a better balanced and more rounded view of the hereditarian-statistical work of Pearson, Weldon, and the biometricians is long overdue. PMID:11619806

Magnello, M E

1998-01-01

106

The Beta Distribution,moment method, Karl Pearson and R.A.Fisher  

Microsoft Academic Search

Simulation studies provide four moment approximating distributions to each of the four parameters of a beta distribution (Pearson Type I). Two of the parameters refer to origin and scale, two to shape (skewness and kurtosis). Type I random number generator is checked out, and the stability of moments of random samples of size n over cycles; particular attention is paid

K. O. BOWMAN; Kimiko o

2007-01-01

107

The Beta Distribution,moment method, Karl Pearson and R.A.Fisher  

SciTech Connect

Simulation studies provide four moment approximating distributions to each of the four parameters of a beta distribution (Pearson Type I). Two of the parameters refer to origin and scale, two to shape (skewness and kurtosis). Type I random number generator is checked out, and the stability of moments of random samples of size n over cycles; particular attention is paid to shape parameter moments. In Type I region of validity (referred to skewness and kurtosis), moment methods become unstable in the neighborhood of Type III ({chi}{sup 2}) line, and ultimately abort. Thus extremely large variances and large higher moments arise. We probe the cause of this phenomenon. Simulation studies are turned to since alternative power series methods are forbiddingly complicated. However, use is made of the delta method to provide asymptotic variances of the estimators, and asymptotic variances of percentage points of the basic distribution. An account of work on the subject by K. Pearson, some of it a century ago, is given. In particular an important paper by Pearson and Filon provides some estimates of probable errors of moment parameter estimators such as the basic distribution parameters, the mode, the skewness and others. The heated controversy between Pearson and Fisher is considered.

Bowman, Kimiko o [ORNL

2007-01-01

108

“Describing our whole experience”: The statistical philosophies of W. F. R. Weldon and Karl Pearson  

Microsoft Academic Search

There are two motivations commonly ascribed to historical actors for taking up statistics: to reduce complicated data to a mean value (e.g., Quetelet), and to take account of diversity (e.g., Galton). Different motivations will, it is assumed, lead to different methodological decisions in the practice of the statistical sciences. Karl Pearson and W. F. R. Weldon are generally seen as

Charles H. Pence

2011-01-01

109

"Describing our whole experience": the statistical philosophies of W. F. R. Weldon and Karl Pearson.  

PubMed

There are two motivations commonly ascribed to historical actors for taking up statistics: to reduce complicated data to a mean value (e.g., Quetelet), and to take account of diversity (e.g., Galton). Different motivations will, it is assumed, lead to different methodological decisions in the practice of the statistical sciences. Karl Pearson and W. F. R. Weldon are generally seen as following directly in Galton's footsteps. I argue for two related theses in light of this standard interpretation, based on a reading of several sources in which Weldon, independently of Pearson, reflects on his own motivations. First, while Pearson does approach statistics from this "Galtonian" perspective, he is, consistent with his positivist philosophy of science, utilizing statistics to simplify the highly variable data of biology. Weldon, on the other hand, is brought to statistics by a rich empiricism and a desire to preserve the diversity of biological data. Secondly, we have here a counterexample to the claim that divergence in motivation will lead to a corresponding separation in methodology. Pearson and Weldon, despite embracing biometry for different reasons, settled on precisely the same set of statistical tools for the investigation of evolution. PMID:22035721

Pence, Charles H

2011-12-01

110

Determining Differences in Efficacy of Two Disinfectants Using t-Tests.  

ERIC Educational Resources Information Center

Presents an experiment to compare the effectiveness of 95% ethanol to 20% bleach as disinfectants using t-tests for the statistical analysis of the data. Reports that bleach is a better disinfectant. Discusses the statistical and practical significance of the results. (JRH)

Brehm, Michael A.; And Others

1996-01-01

111

Testing Non-Nil Null Hypotheses with t Tests of Group Means: A Monte Carlo Study.  

ERIC Educational Resources Information Center

Statistical significance and practical significance can be considered jointly through the use of non-nil null hypotheses that are based on values deemed to be practically significant. When examining differences between the means of two groups, researchers can use a randomization test or an independent t test. The issue addressed in this paper is…

Newman, Isadore; Fraas, John W.; Herbert, Alan

112

Use of "t"-Test and ANOVA in Career-Technical Education Research  

ERIC Educational Resources Information Center

Use of t-tests and analysis of variance (ANOVA) procedures in published research from three scholarly journals in career and technical education (CTE) during a recent 5-year period was examined. Information on post hoc analyses, reporting of effect size, alpha adjustments to account for multiple tests, power, and examination of assumptions…

Rojewski, Jay W.; Lee, In Heok; Gemici, Sinan

2012-01-01

113

The Two Sample T-test with One Variance Unknown Arnab Maity  

E-print Network

where one of the variances is assumed to be known and the other is treated as unknown. This situation known and one unknown. An interesting observation is that the method of deriving Satterthwaite known and the other one is estimated. We derive the approximate t-test in the case of one unknown

Maity, Arnab

114

Magnetic resonance imaging (MRI)-guided transurethral ultrasound therapy of the prostate: a preclinical study with radiological and pathological correlation using customised MRI-based moulds  

PubMed Central

Objective To characterise the feasibility and safety of a novel transurethral ultrasound (US)-therapy device combined with real-time multi-plane magnetic resonance imaging (MRI)-based temperature monitoring and temperature feedback control, to enable spatiotemporally precise regional ablation of simulated prostate gland lesions in a preclinical canine model. To correlate ablation volumes measured with intra-procedural cumulative thermal damage estimates, post-procedural MRI, and histopathology. Materials and methods Three dogs were treated with three targeted ablations each, using a prototype MRI-guided transurethral US-therapy system (Philips Healthcare, Vantaa, Finland). MRI provided images for treatment planning, guidance, real-time multi-planar thermometry, as well as post-treatment evaluation of efficacy. After treatment, specimens underwent histopathological analysis to determine the extent of necrosis and cell viability. Statistical analyses (Pearson’s correlation, Student’s t-test) were used to evaluate the correlation between ablation volumes measured with intra-procedural cumulative thermal damage estimates, post-procedural MRI, and histopathology. Results MRI combined with a transurethral US-therapy device enabled multi-planar temperature monitoring at the target as well as in surrounding tissues, allowing for safe, targeted, and controlled ablations of prescribed lesions. Ablated volumes measured by cumulative thermal dose positively correlated with volumes determined by histopathological analysis (r2 0.83, P < 0.001). Post-procedural contrast-enhanced and diffusion-weighted MRI showed a positive correlation with non-viable areas on histopathological analysis (r2 0.89, P < 0.001, and r20.91, P = 0.003, respectively). Additionally, there was a positive correlation between ablated volumes according to cumulative thermal dose and volumes identified on post-procedural contrast-enhanced MRI (r2 0.77, P < 0.01). There was no difference in mean ablation volumes assessed with the various analysis methods (P > 0.05, Student’s t-test). Conclusions MRI-guided transurethral US therapy enabled safe and targeted ablations of prescribed lesions in a preclinical canine prostate model. Ablation volumes were reliably predicted by intra- and post-procedural imaging. Clinical studies are needed to confirm the feasibility, safety, oncological control, and functional outcomes of this therapy in patients in whom focal therapy is indicated. PMID:23746198

Partanen, Ari; Yerram, Nitin K.; Trivedi, Hari; Dreher, Matthew R.; Oila, Juha; Hoang, Anthony N.; Volkin, Dmitry; Nix, Jeffrey; Turkbey, Baris; Bernardo, Marcelino; Haines, Diana C.; Benjamin, Compton J.; Linehan, W. Marston; Choyke, Peter; Wood, Bradford J.; Ehnholm, Gösta J.; Venkatesan, Aradhana M.; Pinto, Peter A.

2013-01-01

115

Choosing the Best Correction Formula for the Pearson r[superscript 2] Effect Size  

ERIC Educational Resources Information Center

In the present Monte Carlo simulation study, the authors compared bias and precision of 7 sampling error corrections to the Pearson r[superscript 2] under 6 x 3 x 6 conditions (i.e., population ? values of 0.0, 0.1, 0.3, 0.5, 0.7, and 0.9, respectively; population shapes normal, skewness = kurtosis = 1, and skewness = -1.5 with kurtosis = 3.5;…

Skidmore, Susan Troncoso; Thompson, Bruce

2011-01-01

116

Pearson random walk algorithms for fiber-scale modeling of Chemical Vapor Infiltration  

Microsoft Academic Search

Chemical Vapor Infiltration (CVI) is a popular processing route for the preparation of high-quality Ceramic-Matrix Composites which involves rarefied gas transfer in a disordered fibrous array and heterogeneous deposition reactions. The fiber-scale modeling of CVI in large 3D images of actual porous media (e.g. tomographic images) is a challenging task. We address it with a numerical method based on Pearson

G. L. Vignoles; W. Ros; C. Mulat; O. Coindreau; C. Germain

2011-01-01

117

Wanted: guidelines for reporting correlations  

NSDL National Science Digital Library

Recently (1Â?3), there have been guidelines published for authors regarding what and how statistics should be reported when describing the differences between groups of observations. There seems to be a paucity of such guidance with respect to describing the correlation between groups of observations. Of particular concern to me is the way in which Pearson product-moment correlations are reported in many journals.

Bartholomew Kay (University of Auckland Sport and Exercise Science)

2009-06-01

118

When t-tests or Wilcoxon-Mann-Whitney tests won't do  

NSDL National Science Digital Library

t-Tests are widely used by researchers to compare the average values of a numeric outcome between two groups. If there are doubts about the suitability of the data for the requirements of a t-test, most notably the distribution being non-normal, the Wilcoxon-Mann-Whitney test may be used instead. However, although often applied, both tests may be invalid when discrete and/or extremely skew data are analyzed. In medicine, extremely skewed data having an excess of zeroes are often observed, representing a numeric outcome that does not occur for a large percentage of cases (so is often zero) but which also sometimes takes relatively large values. For data such as this, application of the t-test or Wilcoxon-Mann-Whitney test could lead researchers to draw incorrect conclusions. A valid alternative is regression modeling to quantify the characteristics of the data. The increased availability of software has simplified the application of these more complex statistical analyses and hence facilitates researchers to use them. In this article, we illustrate the methodology applied to a comparison of cyst counts taken from control and steroid-treated fetal mouse kidneys.

Fiona McElduff (University College London)

2010-09-01

119

The Pearson-Readhead Survey of Compact Extragalactic Radio Sources From Space. II. Analysis of Source Properties  

E-print Network

We have performed a multi-dimensional correlation analysis on the observed properties of a statistically complete core-selected sample of compact radio-loud active galactic nuclei, based on data from the VLBI Space Observing Programme (Paper I) and previously published studies. Our sample is drawn from the well-studied Pearson-Readhead (PR) survey, and is ideally suited for investigating the general effects of relativistic beaming in compact radio sources. In addition to confirming many previously known correlations, we have discovered several new trends that lend additional support to the beaming model. These trends suggest that the most highly beamed sources in core-selected samples tend to have a) high optical polarizations; b) large pc/kpc-scale jet misalignments; c) prominent VLBI core components; d) one-sided, core, or halo radio morphology on kiloparsec scales; e) narrow emission line equivalent widths; and f) a strong tendency for intraday variability at radio wavelengths. We have used higher resolution space and ground-based VLBI maps to confirm the bi-modality of the jet misalignment distribution for the PR survey, and find that the sources with aligned parsec- and kiloparsec-scale jets generally have arcsecond-scale radio emission on both sides of the core. The aligned sources also have broader emission line widths. We find evidence that the BL Lacertae objects in the PR survey are all highly beamed, and have very similar properties to the high-optically polarized quasars, with the exception of smaller redshifts. A cluster analysis on our data shows that after partialing out the effects of redshift, the luminosities of our sample objects in various wave bands are generally well-correlated with each other, but not with other source properties.

M. L. Lister; S. J. Tingay; R. A. Preston

2001-02-15

120

Computers and the severely physically handicapped: a pilot project at Pearson Hospital.  

PubMed

Computers are a rapidly developing technology affecting the lives of everyone, including those in the handicapped population. Major revolutions are occurring in the technology available for physically and mentally handicapped persons. This article presents the results and findings of a pilot computer project that was implemented at Pearson Hospital. The use of the computer, adapted to persons of severe physical disability, as a typewriter, a programming device, and as a word processor is explained. The success of the program, and the difficulties experienced in making it run, are presented, along with suggestions for setting up and implementing computer projects in other institutions. An assessment form for potential computer users is presented. PMID:10317249

Stride, B

1982-10-01

121

Calculating and reporting effect sizes to facilitate cumulative science: a practical primer for t-tests and ANOVAs  

PubMed Central

Effect sizes are the most important outcome of empirical studies. Most articles on effect sizes highlight their importance to communicate the practical significance of results. For scientists themselves, effect sizes are most useful because they facilitate cumulative science. Effect sizes can be used to determine the sample size for follow-up studies, or examining effects across studies. This article aims to provide a practical primer on how to calculate and report effect sizes for t-tests and ANOVA's such that effect sizes can be used in a-priori power analyses and meta-analyses. Whereas many articles about effect sizes focus on between-subjects designs and address within-subjects designs only briefly, I provide a detailed overview of the similarities and differences between within- and between-subjects designs. I suggest that some research questions in experimental psychology examine inherently intra-individual effects, which makes effect sizes that incorporate the correlation between measures the best summary of the results. Finally, a supplementary spreadsheet is provided to make it as easy as possible for researchers to incorporate effect size calculations into their workflow. PMID:24324449

Lakens, Daniël

2013-01-01

122

Distribution of eigenvalues of detrended cross-correlation matrix  

NASA Astrophysics Data System (ADS)

This letter is devoted to the cross-correlation analysis of non-stationary multivariate data, in which the detrended cross-correlation matrix based on the detrended cross-correlation coefficient is studied. The relationship between Pearson's cross-correlation coefficient and the detrended cross-correlation coefficient is analyzed. As a special case of random matrix theory, the distribution of the eigenvalues of the detrended cross-correlation matrix for purely random variables is derived.

Zhao, Xiaojun; Shang, Pengjian; Lin, Aijing

2014-08-01

123

Independent Samples t-Test: Chips Ahoyî vs. Supermarket Brand  

NSDL National Science Digital Library

In this hands-on activity, created by Dex Whittinghill of Rowan University, students count the number of chips in cookies in order to carry out an independent samples t-test to see if Chips Ahoyî cookies have a higher, lower, or different mean number of chips per cookie than a supermarket brand. First there is a class discussion that can include concepts about random samples, independence of samples, recently covered tests, comparing two parameters with null and alternative hypotheses, what it means to be a chip in a cookie, how to break up the cookies to count chips, and of course a class consensus on the hypotheses to be tested. Second the students count the number of chips in a one cookie from each brand, and report their observations to the instructor. Third, the instructor develops the independent sample t-test statistic. Fourth, the students carry out (individually or as a class) the hypothesis test, checking the assumptions on sample-size/population-shape.

Whittinghill, Dex

2009-07-23

124

Infiltrating mast cells correlate with angiogenesis in bone metastases from gastric cancer patients.  

PubMed

While gastric cancer is a well established angiogenesis driven tumor, no data has been published regarding angiogenesis stimulated by mast cells (MCs) positive for tryptase in bone metastases from gastric cancer patients (BMGCP). It is well established that MCs play a role in immune responses and more recently it was demonstrated that MCs have been involved in tumor angiogenesis. We analyzed infiltrating MCs and neovascularization in BMGCP diagnosed by histology. A series of 15 stage T3-4N2-3M1 (by AJCC for Gastric Cancer Staging 7th Edition) BMGCP from bone biopsies were selected. Tumour tissue samples were evaluated by mean of immunohistochemistry and image analysis methods in terms of MCs density positive to tryptase (MCDPT), MCs area positive to tryptase (MCAPT), microvascular density (MVD) and endothelial area (EA). A significant correlation between MCDPT, MCAPT, MVD and EA groups to each other was found by Pearson and t-test analysis (r ranged from 0.68 to 0.82; p-value ranged from 0.00 to 0.02). Our very preliminary data suggest that infiltrating MCs positive for tryptase may play a role in BMGCP angiogenesis, and could be further evaluated as a novel target of anti-angiogenic therapy. PMID:25648323

Ammendola, Michele; Marech, Ilaria; Sammarco, Giuseppe; Zuccalà, Valeria; Luposella, Maria; Zizzo, Nicola; Patruno, Rosa; Crovace, Alberto; Ruggieri, Eustachio; Zito, Alfredo Francesco; Gadaleta, Cosmo Damiano; Sacco, Rosario; Ranieri, Girolamo

2015-01-01

125

Correlation between changes in quality of life and symptomatic improvement in Chinese patients switched from typical antipsychotics to olanzapine  

PubMed Central

Purpose The aim of this study was to investigate the correlation between changes in symptoms and changes in self-reported quality of life among Chinese patients with schizophrenia who were switched from a typical antipsychotic to olanzapine during usual outpatient care. Patients and methods This post hoc analysis was conducted using data from the Chinese subgroup (n=475) of a multicountry, 12-month, prospective, noninterventional, observational study. The primary publication previously reported the efficacy, safety, and quality of life among patients who switched from a typical antipsychotic to olanzapine. Patients with schizophrenia were included if their symptoms were inadequately controlled with a typical antipsychotic and they were switched to olanzapine. Symptom severity was measured using the Brief Psychiatric Rating Scale (BPRS) and the Clinical Global Impressions-Severity scale (CGI-S). Health-Related Quality of Life (HRQOL) was assessed using the World Health Organization Quality of Life–Abbreviated (WHOQOL-BREF). Paired t-tests were performed to assess changes from baseline to endpoint. Pearson’s correlation coefficients (r) were used to assess the correlations between change in symptoms (BPRS and CGI-S scores) and change in HRQOL (WHOQOL-BREF scores). Results Symptoms and HRQOL both improved significantly over the 12 months of treatment (P<0.001). Significant correlations were observed between changes from baseline to end of study on the BPRS and the CGI-S and each of the WHOQOL-BREF four domain scores and two overall quality-of-life questions. The correlation coefficients ranged from r=?0.45 to r=?0.53 for the BPRS and WHOQOL-BREF. The correlation coefficients were slightly smaller between the CGI-S and WHOQOL-BREF, ranging from r=?0.33 to r=?0.40. Conclusion For patients with schizophrenia, assessing quality of life has the potential to add valuable information to the clinical assessment that takes into account the patient’s own perspective of well-being. PMID:25632235

Montgomery, William; Kadziola, Zbigniew; Ye, Wenye; Xue, Hai Bo; Liu, Li; Treuer, Tamás

2015-01-01

126

A modified weighted function method for parameter estimation of Pearson type three distribution  

NASA Astrophysics Data System (ADS)

this paper, an unconventional method called Modified Weighted Function (MWF) is presented for the conventional moment estimation of a probability distribution function. The aim of MWF is to estimate the coefficient of variation (CV) and coefficient of skewness (CS) from the original higher moment computations to the first-order moment calculations. The estimators for CV and CS of Pearson type three distribution function (PE3) were derived by weighting the moments of the distribution with two weight functions, which were constructed by combining two negative exponential-type functions. The selection of these weight functions was based on two considerations: (1) to relate weight functions to sample size in order to reflect the relationship between the quantity of sample information and the role of weight function and (2) to allocate more weights to data close to medium-tail positions in a sample series ranked in an ascending order. A Monte-Carlo experiment was conducted to simulate a large number of samples upon which statistical properties of MWF were investigated. For the PE3 parent distribution, results of MWF were compared to those of the original Weighted Function (WF) and Linear Moments (L-M). The results indicate that MWF was superior to WF and slightly better than L-M, in terms of statistical unbiasness and effectiveness. In addition, the robustness of MWF, WF, and L-M were compared by designing the Monte-Carlo experiment that samples are obtained from Log-Pearson type three distribution (LPE3), three parameter Log-Normal distribution (LN3), and Generalized Extreme Value distribution (GEV), respectively, but all used as samples from the PE3 distribution. The results show that in terms of statistical unbiasness, no one method possesses the absolutely overwhelming advantage among MWF, WF, and L-M, while in terms of statistical effectiveness, the MWF is superior to WF and L-M.

Liang, Zhongmin; Hu, Yiming; Li, Binquan; Yu, Zhongbo

2014-04-01

127

Correlation Analysis between Complex Relative Permittivity and Biochemical Components for Blood of Dialysis Patients before and after Hemodialysis  

NASA Astrophysics Data System (ADS)

We previously measured for healthy subjects and patients who require hemodialysis the complex relative permittivity (?r´-j?r´´) of whole blood, and found that ?r´-axis intercept ?rt´ of straight line approximation to the Cole-Cole plots at frequencies from 200 MHz to 1GHz is significantly different with a level of less than 1% among its averaged values for healthy subjects and patients before and after dialysis, though any correlations between ?rt´ and blood urea nitrogen (BUN) and creatinine being used as main indices for hemodialysis evaluation have not so far been clarified. In this study, to make correlation analyses between the intercept ?rt´ and blood biochemical components for nine patients before and after hemodialysis, we measured six kinds of their blood components including BUN and creatinine, and calculated their Pearson product-moment correlation coefficients for ?rt´ along with significant probability P based on a t-test. It should be noted that P is a reference probability to determine whether or not a null hypothesis can be rejected, and that the P value of 0.05 is commonly used as a significance level for statistical test. As a result, we found that a strong correlation with P < 0.05 is observed between ?rt´ and albumin, while there are not always significant correlations with P > 0.05 between ?rt´ and other blood components including BUN and creatinine. Although albumin is not used as an index for hemodialysis efficiency, it can reflect water amount in blood vessels and liver operation. This finding implies that ?rt´ could be used as an index for evaluating blood viscosity and liver function.

Takeda, Akira; Takata, Kazuyuki; Nagao, Hirotomo; Wang, Jianqing; Fujiwara, Osamu

128

A Correlation of Permanent Anterior Tooth Fracture with Type of Occlusion and Craniofacial Morphology  

PubMed Central

ABSTRACT Aims: To assess the relationship of anterior tooth fractures with type of occlusion and craniofacial morphology. Materials and methods: The study was conducted on 76 subjects of age group 9 to 13 years with at least one fractured permanent anterior teeth. Lateral cephalograms were taken and study models were prepared for each subject with prior consent of their parents. Then cephalometric tracings were done and overjet was recorded through study models. Statistical analysis used: Standard error of mean (SEM) and unpaired t-test has been applied to test the significant difference between the seven parameters under consideration. Karl Pearson correlation test has also been used to correlate all the parameters used in this study with each other. All the tests were performed at 5 and 1% levels of significance. Results: Frequency of tooth fracture increases with increasing overjet. At 5% level of significance, significant difference were observed between the standard values and observed values for overjet measurement, SNA angle, SNB angle, ANB angle, upper incisor to NA (angle), upper incisor to NA (linear) and interincisal angle for overall data and also for both male and female data separately. Conclusion: Probability of permanent anterior tooth fracture increases with increasing overjet. A significant difference was observed between the standard value and the observed values of all parameters under consideration. How to cite this article: Chaturvedi R, Kumar A, Rana V, Aggarwal A, Chandra L. A Correlation of Permanent Anterior Tooth Fracture with Type of Occlusion and Craniofacial Morphology. Int J Clin Pediatr Dent 2013;6(2):80-84. PMID:25206197

Kumar, Ashish; Rana, Vivek; Aggarwal, Abhai; Chandra, Lokesh

2013-01-01

129

MIMO RADAR DIVERSITY WITH NEYMAN-PEARSON SIGNAL DETECTION IN NON-GAUSSIAN CIRCUMSTANCE WITH NON-ORTHOGONAL WAVEFORMS  

E-print Network

MIMO RADAR DIVERSITY WITH NEYMAN-PEARSON SIGNAL DETECTION IN NON-GAUSSIAN CIRCUMSTANCE WITH NON-Gaussian clutter-plus-noise. It is found that the diversity gain for the MIMO radar system is dependent, signal space. 1. INTRODUCTION Diversity gain is one of the most significant advantage of the MIMO radar

Blum, Rick

130

A Pearson Random Walk with Steps of Uniform Orientation and Dirichlet Distributed Lengths  

NASA Astrophysics Data System (ADS)

A constrained diffusive random walk of n steps in ? d and a random flight in ? d , which are equivalent, were investigated independently in recent papers (J. Stat. Phys. 127:813, 2007; J. Theor. Probab. 20:769, 2007, and J. Stat. Phys. 131:1039, 2008). The n steps of the walk are independent and identically distributed random vectors of exponential length and uniform orientation. Conditioned on the sum of their lengths being equal to a given value l, closed-form expressions for the distribution of the endpoint of the walk were obtained altogether for any n for d=1,2,4. Uniform distributions of the endpoint inside a ball of radius l were evidenced for a walk of three steps in 2D and of two steps in 4D. The previous walk is generalized by considering step lengths which have independent and identical gamma distributions with a shape parameter q>0. Given the total walk length being equal to 1, the step lengths have a Dirichlet distribution whose parameters are all equal to q. The walk and the flight above correspond to q=1. Simple analytical expressions are obtained for any d?2 and n?2 for the endpoint distributions of two families of walks whose q are integers or half-integers which depend solely on d. These endpoint distributions have a simple geometrical interpretation. Expressed for a two-step planar walk whose q=1, it means that the distribution of the endpoint on a disc of radius 1 is identical to the distribution of the projection on the disc of a point M uniformly distributed over the surface of the 3D unit sphere. Five additional walks, with a uniform distribution of the endpoint in the inside of a ball, are found from known finite integrals of products of powers and Bessel functions of the first kind. They include four different walks in ?3, two of two steps and two of three steps, and one walk of two steps in ?4. Pearson-Liouville random walks, obtained by distributing the total lengths of the previous Pearson-Dirichlet walks according to some specified probability law are finally discussed. Examples of unconstrained random walks, whose step lengths are gamma distributed, are more particularly considered.

Le Caër, Gérard

2010-08-01

131

Log Pearson type 3 quantile estimators with regional skew information and low outlier adjustments  

USGS Publications Warehouse

[1] The recently developed expected moments algorithm (EMA) [Cohn et al., 1997] does as well as maximum likelihood estimations at estimating log-Pearson type 3 (LP3) flood quantiles using systematic and historical flood information. Needed extensions include use of a regional skewness estimator and its precision to be consistent with Bulletin 17B. Another issue addressed by Bulletin 17B is the treatment of low outliers. A Monte Carlo study compares the performance of Bulletin 17B using the entire sample with and without regional skew with estimators that use regional skew and censor low outliers, including an extended EMA estimator, the conditional probability adjustment (CPA) from Bulletin 17B, and an estimator that uses probability plot regression (PPR) to compute substitute values for low outliers. Estimators that neglect regional skew information do much worse than estimators that use an informative regional skewness estimator. For LP3 data the low outlier rejection procedure generally results in no loss of overall accuracy, and the differences between the MSEs of the estimators that used an informative regional skew are generally modest in the skewness range of real interest. Samples contaminated to model actual flood data demonstrate that estimators which give special treatment to low outliers significantly outperform estimators that make no such adjustment.

Griffis, V.W.; Stedinger, J.R.; Cohn, T.A.

2004-01-01

132

Bootstrap Standard Error and Confidence Intervals for the Correlation Corrected for Range Restriction: A Simulation Study  

ERIC Educational Resources Information Center

The standard Pearson correlation coefficient is a biased estimator of the true population correlation, ?, when the predictor and the criterion are range restricted. To correct the bias, the correlation corrected for range restriction, r-sub(c), has been recommended, and a standard formula based on asymptotic results for estimating its standard…

Chan, Wai; Chan, Daniel W.-L.

2004-01-01

133

Technical note: Correlation between TQA data trends and TomoHD functional status.  

PubMed

TomoTherapy Quality Assurance (TQA) is a software package developed to monitor certain aspects of machine performance. In this study, the TQA quantities or data trends most effective in monitoring energy drifts and magnetron stability were determined respectively. This retrospective study used data collected from three TomoHD units. The TQA modules investigated were Step-Wedge Helical, Step-Wedge Static, and Basic Dosimetry. First, the TQA quantities correlated with energy changes (|r| > 0.85, where r is the Pearson's correlation coefficient) were found. The corresponding sensitivities to percentage depth dose (PDD) ratio changes were then calculated and compared. Second, the pulse-by-pulse dose stability was compared before and after each magnetron replacement using a nonparametric comparison test (Welch's t-test), and the raw dose profiles were surveyed. In this study, exit detector flatness obtained in Basic Dosimetry was shown to be the most sensitive (r = 0.945) to energy changes, followed by the energy differences in Step-Wedge Static (r = 0.942) and Step-Wedge Helical (r = 0.898). The three quantities could detect a PDD ratio change of 5.1 × 10??, 5.4 × 10??, and 7.1× 10??, respectively. Pulse-by-Pulse Dose1 from Basic Dosimetry over a one-week period before and after a magnetron replacement showed a significant difference (p < 0.05) in only three of the nine instances. On the other hand, a raw output profile free from discontinuities, frequent dropped pulses and abnormal spikes was found to indicate that the magnetron would continue to function normally for a week 89% of the time. PMID:24710441

Choi, Hervé H F; Ho, Joan P Y; Yang, Bin; Cheung, Kin Yin; Yu, Siu Ki

2014-01-01

134

Correlation between Burning Mouth Syndrome and Anxiety in the Elderly Inmates of Sanitaria in Tehran  

PubMed Central

Background and aims Burning mouth syndrome (BMS) is a chronic pain disorder characterized by a chief complaint of oral burning/pain with no clinically observable oral mucosal lesions. The prevalence of BMS has been reported to be 2.5-5.1% in the general population and several psychological disorders have been reported as associated or predisposing factors for BMS. The aim of this study was to determine the correlation between BMS and anxiety in the elderly residents of sani-taria in Tehran, Iran. Materials and methods In a cross-sectional analytical study, 50 patients with BMS were included along with 50 healthy individuals as controls. Inclusion criteria were: age over 60 years, burning sensation in the mouth, normal oral mu-cosa, absence of diabetes, satisfactory prosthesis, absence of iron deficiency and other nutrients, and no heavy smoking habits. Similar inclusion criteria were considered for the control group without any oral complaints. Burning/pain severity was assessed by a 100-mm visual analog scale and the severity of anxiety (state, trait, and total) was determined by Cattell's Anxiety Scale. Data was analyzed by t-test and Pearson's correlation coefficient. Results Individuals with BMS assessed their burning/pain severity to be 27.4 mm (95% CI=25.2 - 29.6 mm). Standard-ized total anxiety scale in individuals with and without BMS (±SE for mean) was 5.9±0.2 and 4.6±0.3 with significant dif-ferences (p=0.001). Similar significant differences were observed in state and trait anxiety between the two groups. Conclusion It seems that both state and trait anxiety are associated with burning mouth syndrome. PMID:22991594

Bakhtiari, Sedighe; Khalighi, Hamid Reza; Azimi, Somayyeh; Alavi, Kaveh; Ayoobi Valoogerdi, Hasan; Namazi, Zahra

2010-01-01

135

A practical point of view: Performance of Neyman-Pearson detector for MIMO radar in K-distributed clutter  

Microsoft Academic Search

Use of multiple transmit and receive antennas have become a popular research area in radar community after the success of the same concept in communication. It is shown by Fishler et al. that multi-input multi-output (MIMO) radar has considerable advantages compared to traditional radar and phased array radar systems. In this paper, detection performance of MIMO radar using Neyman-Pearson detector

Ayhan Yazici; Aysin Cetin Hamurcu; Buyurman Baykal

2009-01-01

136

Exponential smoothing weighted correlations  

NASA Astrophysics Data System (ADS)

In many practical applications, correlation matrices might be affected by the "curse of dimensionality" and by an excessive sensitiveness to outliers and remote observations. These shortcomings can cause problems of statistical robustness especially accentuated when a system of dynamic correlations over a running window is concerned. These drawbacks can be partially mitigated by assigning a structure of weights to observational events. In this paper, we discuss Pearson's ? and Kendall's ? correlation matrices, weighted with an exponential smoothing, computed on moving windows using a data-set of daily returns for 300 NYSE highly capitalized companies in the period between 2001 and 2003. Criteria for jointly determining optimal weights together with the optimal length of the running window are proposed. We find that the exponential smoothing can provide more robust and reliable dynamic measures and we discuss that a careful choice of the parameters can reduce the autocorrelation of dynamic correlations whilst keeping significance and robustness of the measure. Weighted correlations are found to be smoother and recovering faster from market turbulence than their unweighted counterparts, helping also to discriminate more effectively genuine from spurious correlations.

Pozzi, F.; Di Matteo, T.; Aste, T.

2012-06-01

137

Correlations between wet-milling characteristics of amaranth grain  

Microsoft Academic Search

Relationships of acid wet-milling conditions (soaking temperature and sulfur dioxide concentration) to laboratory wet-milling characteristics (fraction yields, protein content of fractions, and recovery values) of amaranth seeds were determined. Based on correlation coefficients (Pearson matrix), it was found that: (a) starch recovery was significantly correlated to fiber yield (r=?0.74); (b) the correlations of gluten recovery with protein content of starch

Andrea N. Calzetta Resio; Marcela P. Tolaba; Constantino Suárez

2009-01-01

138

Wilcoxon-Mann-Whitney or t-test? On assumptions for hypothesis tests and multiple interpretations of decision rules*  

PubMed Central

In a mathematical approach to hypothesis tests, we start with a clearly defined set of hypotheses and choose the test with the best properties for those hypotheses. In practice, we often start with less precise hypotheses. For example, often a researcher wants to know which of two groups generally has the larger responses, and either a t-test or a Wilcoxon-Mann-Whitney (WMW) test could be acceptable. Although both t-tests and WMW tests are usually associated with quite different hypotheses, the decision rule and p-value from either test could be associated with many different sets of assumptions, which we call perspectives. It is useful to have many of the different perspectives to which a decision rule may be applied collected in one place, since each perspective allows a different interpretation of the associated p-value. Here we collect many such perspectives for the two-sample t-test, the WMW test and other related tests. We discuss validity and consistency under each perspective and discuss recommendations between the tests in light of these many different perspectives. Finally, we briefly discuss a decision rule for testing genetic neutrality where knowledge of the many perspectives is vital to the proper interpretation of the decision rule. PMID:20414472

Fay, Michael P.; Proschan, Michael A.

2010-01-01

139

Decorrelate hyperspectral images using spectral correlation  

NASA Astrophysics Data System (ADS)

This paper proposes a new algorithm for lossless compression of hyperspectral images. In our work we found hyperspectral data have unique characteristic based on spectral context and adjacent pixel spectral vectors (curves) highly correlate with each other. Pearson correlation coefficient is an effective measure of spectral similarity between spectral curves to detect horizontal and vertical spectral edge. Thus, spectral correlation is used to prediction in spectral direction for decorrelation of lossless compression of hyperspectral images. Experiments show the proposed algorithm is effective, and it's more important that it has much lower complexity than other algorithms.

Chen, Liang; Liu, Daizhi; Huang, Shiqi

2007-01-01

140

Correlation of Point B and Lymph Node Dose in 3D-Planned High-Dose-Rate Cervical Cancer Brachytherapy  

SciTech Connect

Purpose: To compare high dose rate (HDR) point B to pelvic lymph node dose using three-dimensional-planned brachytherapy for cervical cancer. Methods and Materials: Patients with FIGO Stage IB-IIIB cervical cancer received 70 tandem HDR applications using CT-based treatment planning. The obturator, external, and internal iliac lymph nodes (LN) were contoured. Per fraction (PF) and combined fraction (CF) right (R), left (L), and bilateral (Bil) nodal doses were analyzed. Point B dose was compared with LN dose-volume histogram (DVH) parameters by paired t test and Pearson correlation coefficients. Results: Mean PF and CF doses to point B were R 1.40 Gy +- 0.14 (CF: 7 Gy), L 1.43 +- 0.15 (CF: 7.15 Gy), and Bil 1.41 +- 0.15 (CF: 7.05 Gy). The correlation coefficients between point B and the D100, D90, D50, D2cc, D1cc, and D0.1cc LN were all less than 0.7. Only the D2cc to the obturator and the D0.1cc to the external iliac nodes were not significantly different from the point B dose. Significant differences between R and L nodal DVHs were seen, likely related to tandem deviation from irregular tumor anatomy. Conclusions: With HDR brachytherapy for cervical cancer, per fraction nodal dose approximates a dose equivalent to teletherapy. Point B is a poor surrogate for dose to specific nodal groups. Three-dimensional defined nodal contours during brachytherapy provide a more accurate reflection of delivered dose and should be part of comprehensive planning of the total dose to the pelvic nodes, particularly when there is evidence of pathologic involvement.

Lee, Larissa J. [Harvard Radiation Oncology Program, Brigham and Women's Hospital, Boston, MA (United States); Sadow, Cheryl A. [Department of Radiology, Brigham and Women's Hospital, Boston, MA (United States); Russell, Anthony [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Viswanathan, Akila N., E-mail: aviswanathan@lroc.harvard.ed [Department of Radiation Oncology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA (United States)

2009-11-01

141

Gastric Antral Vascular Ectasia and Its Clinical Correlates in Patients with Early Diffuse Systemic Sclerosis in the SCOT Trial  

PubMed Central

Objective To describe the prevalence and clinical correlates of endoscopic gastric antral vascular ectasia (GAVE; “watermelon stomach”) in early diffuse systemic sclerosis (SSc). Methods Subjects with early, diffuse SSc and evidence of specific internal organ involvement were considered for the Scleroderma: Cyclophosphamide Or Transplant (SCOT) trial. In the screening procedures, all patients underwent upper gastrointestinal endoscopy. Patients were then categorized into those with or without endoscopic evidence of GAVE. Demographic data, clinical disease characteristics, and autoantibody data were compared using Pearson chi-square or Student t tests. Results Twenty-three of 103 (22.3%) individuals were found to have GAVE on endoscopy. Although not statistically significant, anti-topoisomerase I (anti-Scl70) was detected less frequently among those with GAVE (18.8% vs 44.7%; p = 0.071). Similarly, anti-RNP antibodies (anti-U1 RNP) showed a trend to a negative association with GAVE (0 vs 18.4%; p = 0.066). There was no association between anti-RNA polymerase III and GAVE. Patients with GAVE had significantly more erythema or vascular ectasias in other parts of the stomach (26.1% vs 5.0%; p = 0.003). Conclusion Endoscopic GAVE was present on screening in almost one-fourth of these highly selected patients with early and severe diffuse SSc. While anti-Scl70 and anti-U1 RNP trended toward a negative association with GAVE, there was no correlation between anti-RNA Pol III and GAVE. Patients with GAVE had a higher frequency of other gastric vascular ectasias outside the antrum, suggesting that GAVE may represent part of the spectrum of the vasculopathy in SSc. PMID:23418384

Hung, Emily W.; Mayes, Maureen D.; Sharif, Roozbeh; Assassi, Shervin; Machicao, Victor I.; Hosing, Chitra; St. Clair, E. William; Furst, Daniel E.; Khanna, Dinesh; Forman, Stephen; Mineishi, Shin; Phillips, Kristine; Seibold, James R.; Bredeson, Christopher; Csuka, Mary Ellen; Nash, Richard A.; Wener, Mark H.; Simms, Robert; Ballen, Karen; Leclercq, Sharon; Storek, Jan; Goldmuntz, Ellen; Welch, Beverly; Keyes-Elstein, Lynette; Castina, Sharon; Crofford, Leslie J.; Mcsweeney, Peter; Sullivan, Keith M.

2013-01-01

142

Meta-Analysis of Correlations Revisited: Attempted Replication and Extension of Field's (2001) Simulation Studies  

ERIC Educational Resources Information Center

In 2 Monte Carlo studies of fixed- and random-effects meta-analysis for correlations, A. P. Field (2001) ostensibly evaluated Hedges-Olkin-Vevea Fisher-[zeta] and Schmidt-Hunter Pearson-r estimators and tests in 120 conditions. Some authors have cited those results as evidence not to meta-analyze Fisher-[zeta] correlations, especially with…

Hafdahl, Adam R.; Williams, Michelle A.

2009-01-01

143

Distribution of the Maximum of the Arithmetic Mean of Correlated Random Variables  

Microsoft Academic Search

The initial distribution considered here is obtained from a multivariate analogue of the Pearson Type III distribution, and the value of the correlation is taken to be non-negative. There is obtained here the distribution of the maximum in samples of fixed size $n$ from a random variable which is the arithmetic mean of $k$ such correlated random variables. This distribution

John Gurland

1955-01-01

144

Covariate Adjusted Correlation Analysis with Application to FMR1 Premutation Female Carrier Data  

E-print Network

premutation carriers of the fragile X mental retardation 1 (FMR1) gene, we present a new method of covariate; Mental retardation; Nonparametric partial correlation; Pearson correlation; Semipara- metric modeling X mental retardation 1 (FMR1) X-linked gene (Verkerk et al., 1991; Oberle et al., 1991). When

Sentürk, Damla

145

Power Demodulation of Local Field Potential Recordings S. Pearson and J. McNames  

E-print Network

by the electrodes. Correlated firing rates among neigh- boring neurons are common in many neurological structures the instantaneous firing rate that is common to the neural activity of the most prominent neurons sensed of >0.80 with the common firing rate. This suggests that it may be possible to estimate the common

146

On the correlation of a naturally and an artificially dichotomized variable.  

PubMed

A method is suggested for estimating the correlation of a naturally (X) and an artificially (Y) dichotomized variable. It is assumed that a normal random variable (L) underlies the artificially dichotomized variable. The proposed correlation coefficient recovers the product moment correlation coefficient between X and L from a fourfold table of X and Y. The suggested correlation coefficient nu is contrasted with the phi correlation and the biserial eta. The biserial eta was proposed by Karl Pearson and is conceptually related to the new correlation coefficient. However, in addition, Pearson's biserial eta invokes the assumption that the marginal distribution of L is normal, which contradicts its basic assumptions and thus does not recover the true correlation of L and X. Finally, an approximation is provided to simplify the calculation of nu and its standard error. PMID:15511306

Ulrich, Rolf; Wirtz, Markus

2004-11-01

147

Detecting background changes in environments with dynamic foreground by separating probability distribution function mixtures using Pearson's method of moments  

NASA Astrophysics Data System (ADS)

This paper presents parameter estimation techniques useful for detecting background changes in a video sequence with extreme foreground activity. A specific application of interest is automated detection of the covert placement of threats (e.g., a briefcase bomb) inside crowded public facilities. We propose that a histogram of pixel intensity acquired from a fixed mounted camera over time for a series of images will be a mixture of two Gaussian functions: the foreground probability distribution function and background probability distribution function. We will use Pearson's Method of Moments to separate the two probability distribution functions. The background function can then be "remembered" and changes in the background can be detected. Subsequent comparisons of background estimates are used to detect changes. Changes are flagged to alert security forces to the presence and location of potential threats. Results are presented that indicate the significant potential for robust parameter estimation techniques as applied to video surveillance.

Jenkins, Colleen; Jordan, Jay; Carlson, Jeff

2007-02-01

148

The James Pearson Duffy Department of Art and Art History Newsletter is a publication of the Wayne State University Department of Art and  

E-print Network

FALL NEWSLETTER #12;The James Pearson Duffy Department of Art and Art History Newsletter is a publication of the Wayne State University Department of Art and Art History. Alumni are invited to send of Art and Art History staff. WE ARE ON THE WEB! Visit the Department of Art web site at www.art

Cinabro, David

149

Evaluation of whole effluent toxicity data characteristics and use of Welch's T-test in the test of significant toxicity analysis.  

PubMed

The U.S. Environmental Protection Agency (U.S. EPA) and state agencies evaluate the toxicity of effluent and surface water samples based on statistical endpoints derived from multiconcentration tests (e.g., no observed effect concentration, EC25). The test of significant toxicity (TST) analysis is a two-sample comparison test that uses Welch's t test to compare organism responses in a sample (effluent or surface water) with responses in a control or site sample. In general, any form of t test (Welch's t included) is appropriate only if the data meet assumptions of normality and homogeneous variances. Otherwise, nonparametric tests are recommended. TST was designed to use Welch's t as the statistical test for all whole effluent toxicity (WET) test data. The authors evaluated the suitability of using Welch's t test for analyzing two-sample toxicity (WET) data, and within the TST approach, by examining the distribution and variances of data from over 2,000 WET tests and by conducting multiple simulations of WET test data. Simulated data were generated having variances and nonnormal distributions similar to observed WET test data for control and the effluent treatment groups. The authors demonstrate that (1) moderately unequal variances (similar to WET data) have little effect on coverage of the t test or Welch t test (for normally distributed data), and (2) for nonnormally distributed data (similar in distribution to WET data) TST, using Welch's t test, has close to nominal coverage on the basis of simulations with up to a ninefold difference in variance between the effluent and control groups (?95th percentile based on observed WET test data). PMID:23172744

Zheng, Lei; Diamond, Jerry M; Denton, Debra L

2013-02-01

150

Support vector machine with a Pearson VII function kernel for discriminating halophilic and non-halophilic proteins.  

PubMed

Understanding of proteins adaptive to hypersaline environment and identifying them is a challenging task and would help to design stable proteins. Here, we have systematically analyzed the normalized amino acid compositions of 2121 halophilic and 2400 non-halophilic proteins. The results showed that halophilic protein contained more Asp at the expense of Lys, Ile, Cys and Met, fewer small and hydrophobic residues, and showed a large excess of acidic over basic amino acids. Then, we introduce a support vector machine method to discriminate the halophilic and non-halophilic proteins, by using a novel Pearson VII universal function based kernel. In the three validation check methods, it achieved an overall accuracy of 97.7%, 91.7% and 86.9% and outperformed other machine learning algorithms. We also address the influence of protein size on prediction accuracy and found the worse performance for small size proteins might be some significant residues (Cys and Lys) were missing in the proteins. PMID:23764527

Zhang, Guangya; Ge, Huihua

2013-10-01

151

The Cross-Wavelet Transform and Analysis of Quasiperiodic Behavior in the Pearson-Readhead VLBI Survey Sources  

E-print Network

We introduce an algorithm for applying a cross-wavelet transform to analysis of quasiperiodic variations in a time-series, and introduce significance tests for the technique. We apply a continuous wavelet transform and the cross-wavelet algorithm to the Pearson-Readhead VLBI survey sources using data obtained from the University of Michigan 26-m parabloid at observing frequencies of 14.5, 8.0, and 4.8 GHz. Thirty of the sixty-two sources were chosen to have sufficient data for analysis, having at least 100 data points for a given time-series. Of these thirty sources, a little more than half exhibited evidence for quasiperiodic behavior in at least one observing frequency, with a mean characteristic period of 2.4 yr and standard deviation of 1.3 yr. We find that out of the thirty sources, there were about four time scales for every ten time series, and about half of those sources showing quasiperiodic behavior repeated the behavior in at least one other observing frequency.

Brandon C. Kelly; Philip A. Hughes; Hugh D. Aller; Margo F. Aller

2003-03-24

152

Quantifying meta-correlations in financial markets  

NASA Astrophysics Data System (ADS)

Financial markets are modular multi-level systems, in which the relationships between the individual components are not constant in time. Sudden changes in these relationships significantly affect the stability of the entire system, and vice versa. Our analysis is based on historical daily closing prices of the 30 components of the Dow Jones Industrial Average (DJIA) from March 15th, 1939 until December 31st, 2010. We quantify the correlation among these components by determining Pearson correlation coefficients, to investigate whether mean correlation of the entire portfolio can be used as a precursor for changes in the index return. To this end, we quantify the meta-correlation - the correlation of mean correlation and index return. We find that changes in index returns are significantly correlated with changes in mean correlation. Furthermore, we study the relationship between the index return and correlation volatility - the standard deviation of correlations for a given time interval. This parameter provides further evidence of the effect of the index on market correlations and their fluctuations. Our empirical findings provide new information and quantification of the index leverage effect, and have implications to risk management, portfolio optimization, and to the increased stability of financial markets.

Kenett, Dror Y.; Preis, Tobias; Gur-Gershgoren, Gitit; Ben-Jacob, Eshel

2012-08-01

153

Discrete Pearson distributions  

SciTech Connect

These distributions are generated by a first order recursive scheme which equates the ratio of successive probabilities to the ratio of two corresponding quadratics. The use of a linearized form of this model will produce equations in the unknowns matched by an appropriate set of moments (assumed to exist). Given the moments we may find valid solutions. These are two cases; (1) distributions defined on the non-negative integers (finite or infinite) and (2) distributions defined on negative integers as well. For (1), given the first four moments, it is possible to set this up as equations of finite or infinite degree in the probability of a zero occurrence, the sth component being a product of s ratios of linear forms in this probability in general. For (2) the equation for the zero probability is purely linear but may involve slowly converging series; here a particular case is the discrete normal. Regions of validity are being studied. 11 refs.

Bowman, K.O. (Oak Ridge National Lab., TN (United States)) [Oak Ridge National Lab., TN (United States); Shenton, L.R. (Georgia Univ., Athens, GA (United States)) [Georgia Univ., Athens, GA (United States); Kastenbaum, M.A. (Kastenbaum (M.A.), Basye, VA (United States)) [Kastenbaum (M.A.), Basye, VA (United States)

1991-11-01

154

I just wanted to clarify your claim yesterday that Pearson's linear correlation coefficient () = the slope () estimated from a linear least squares fit of y = x  

E-print Network

coefficient () = the slope () estimated from a linear least squares fit of y = x + on the same data( , ) = The slope derived using linear least squares (minimising MSE etc..) with regressed on i i x y i i x y x x y y x y x x y y y - - = - - ( )( ) ( ) 22 : cov( , ) = (1) Two points are noteworthy: 1. Eqn (1

Masci, Frank

155

The Correlation between Effective Factors of E-learning and Demographic Variables in a Post-Graduate Program of Virtual Medical Education in Tehran University of Medical Sciences.  

PubMed

E-learning as an educational approach has been adopted by diverse educational and academic centers worldwide as it facilitates learning in facing the challenges of the new era in education. Considering the significance of virtual education and its growing practice, it is of vital importance to examine its components for promoting and maintaining success. This analytical cross-sectional study was an  attempt to determine the relationship between four factors of content, educator, learner and system, and effective e-learning in terms of demographic variables, including age, gender, educational background, and marital status of postgraduate master's students (MSc) studying at virtual faculty of Tehran University of Medical Sciences. The sample was selected by census (n=60); a demographic data gathering tool and a researcher-made questionnaire were used to collect data. The face and content validity of both tools were confirmed and the results were analyzed by descriptive statistics (frequency, percentile, standard deviation and mean) and inferential statistics (independent t-test, Scheffe's test, one-way ANOVA and Pearson correlation test) by using SPSS (V.16). The present study revealed that There was no statistically significant relationship between age and marital status and effective e-learning (P>0.05); whereas, there was a statistically significant difference between gender and educational background with effective e-learning (P<0.05). Knowing the extent to which these factors can influence effective e-learning can help managers and designers to make the right decisions about educational components of e-learning, i.e. content, educator, system and learner and improve them to create a more productive learning environment for learners. PMID:25415821

Golband, Farnoosh; Hosseini, Agha Fatemeh; Mojtahedzadeh, Rita; Mirhosseini, Fakhrossadat; Bigdeli, Shoaleh

2014-11-01

156

Fully Automated Decomposition of Raman Spectra into Individual Pearson's Type VII Distributions Applied to Biological and Biomedical Samples.  

PubMed

Rapid technological advances have made the acquisition of large numbers of spectra not only feasible, but also routine. As a result, a significant research effort is focused on semi-automated and fully automated spectral processing techniques. However, the need to provide initial estimates of the number of peaks, their band shapes, and the initial parameters of these bands presents an obstacle to the full automation of peak fitting and its incorporation into fully automated spectral-preprocessing workflows. Moreover, the sensitivity of peak-fit routines to initial parameter settings and the resultant variations in solution quality further impede user-free operation. We have developed a technique to perform fully automated peak fitting on fully automated preconditioned spectra-specifically, baseline-corrected and smoothed spectra that are free of cosmic-ray-induced spikes. Briefly, the tallest peak in a spectrum is located and a Gaussian peak-fit is performed. The fitted peak is then subtracted from the spectrum, and the procedure is repeated until the entire spectrum has been processed. In second and third passes, all the peaks in the spectrum are fitted concurrently, but are fitted to a Pearson Type VII model using the parameters for the model established in the prior pass. The technique is applied to a synthetic spectrum with several peaks, some of which have substantial overlap, to test the ability of the method to recover the correct number of peaks, their true shape, and their appropriate parameters. Finally the method is tested on measured Raman spectra collected from human embryonic stem cells and samples of red blood cells. PMID:25498957

Schulze, H Georg; Atkins, Chad G; Devine, Dana V; Blades, Michael W; Turner, Robin F B

2015-01-01

157

Comparisons of two moments-based estimators that utilize historical and paleoflood data for the log Pearson type III distribution  

USGS Publications Warehouse

The expected moments algorithm (EMA) [Cohn et al., 1997] and the Bulletin 17B [Interagency Committee on Water Data, 1982] historical weighting procedure (B17H) for the log Pearson type III distribution are compared by Monte Carlo computer simulation for cases in which historical and/or paleoflood data are available. The relative performance of the estimators was explored for three cases: fixed-threshold exceedances, a fixed number of large floods, and floods generated from a different parent distribution. EMA can effectively incorporate four types of historical and paleoflood data: floods where the discharge is explicitly known, unknown discharges below a single threshold, floods with unknown discharge that exceed some level, and floods with discharges described in a range. The B17H estimator can utilize only the first two types of historical information. Including historical/paleoflood data in the simulation experiments significantly improved the quantile estimates in terms of mean square error and bias relative to using gage data alone. EMA performed significantly better than B17H in nearly all cases considered. B17H performed as well as EMA for estimating X100 in some limited fixed-threshold exceedance cases. EMA performed comparatively much better in other fixed-threshold situations, for the single large flood case, and in cases when estimating extreme floods equal to or greater than X500. B17H did not fully utilize historical information when the historical period exceeded 200 years. Robustness studies using GEV-simulated data confirmed that EMA performed better than B17H. Overall, EMA is preferred to B17H when historical and paleoflood data are available for flood frequency analysis.

England, J.F., Jr.; Salas, J.D.; Jarrett, R.D.

2003-01-01

158

Asymmetric correlation matrices: an analysis of financial data  

NASA Astrophysics Data System (ADS)

We analyse the spectral properties of correlation matrices between distinct statistical systems. Such matrices are intrinsically non-symmetric, and lend themselves to extend the spectral analyses usually performed on standard Pearson correlation matrices to the realm of complex eigenvalues. We employ some recent random matrix theory results on the average eigenvalue density of this type of matrix to distinguish between noise and non-trivial correlation structures, and we focus on financial data as a case study. Namely, we employ daily prices of stocks belonging to the American and British stock exchanges, and look for the emergence of correlations between two such markets in the eigenvalue spectrum of their non-symmetric correlation matrix. We find several non trivial results when considering time-lagged correlations over short lags, and we corroborate our findings by additionally studying the asymmetric correlation matrix of the principal components of our datasets.

Livan, G.; Rebecchi, L.

2012-06-01

159

Weighted network analysis of high-frequency cross-correlation measures  

NASA Astrophysics Data System (ADS)

In this paper we implement a Fourier method to estimate high-frequency correlation matrices from small data sets. The Fourier estimates are shown to be considerably less noisy than the standard Pearson correlation measures and thus capable of detecting subtle changes in correlation matrices with just a month of data. The evolution of correlation at different time scales is analyzed from the full correlation matrix and its minimum spanning tree representation. The analysis is performed by implementing measures from the theory of random weighted networks.

Iori, Giulia; Precup, Ovidiu V.

2007-03-01

160

On the insignificance of Herschel's sunspot correlation  

NASA Astrophysics Data System (ADS)

We examine William Herschel's hypothesis that solar-cycle variation of the Sun's irradiance has a modulating effect on the Earth's climate and that this is, specifically, manifested as an anticorrelation between sunspot number and the market price of wheat. Since Herschel first proposed his hypothesis in 1801, it has been regarded with both interest and skepticism. Recently, reports have been published that either support Herschel's hypothesis or rely on its validity. As a test of Herschel's hypothesis, we seek to reject a null hypothesis of a statistically random correlation between historical sunspot numbers, wheat prices in London and the United States, and wheat farm yields in the United States. We employ binary-correlation, Pearson-correlation, and frequency-domain methods. We test our methods using a historical geomagnetic activity index, well known to be causally correlated with sunspot number. As expected, the measured correlation between sunspot number and geomagnetic activity would be an unlikely realization of random data; the correlation is "statistically significant." On the other hand, measured correlations between sunspot number and wheat price and wheat yield data would be very likely realizations of random data; these correlations are "insignificant." Therefore, Herschel's hypothesis must be regarded with skepticism. We compare and contrast our results with those of other researchers. We discuss procedures for evaluating hypotheses that are formulated from historical data.

Love, Jeffrey J.

2013-08-01

161

Subglottic stenosis: correlation between computed tomography and bronchoscopy.  

PubMed

The evaluation of subglottic stenosis has been limited by the lack of standardized methods for determining the cross-sectional area and length of the stenotic segment. A rabbit model was used to prospectively evaluate the correlation between computed tomography (CT) and bronchoscopy in the evaluation of this disease. Subglottic stenosis was produced in 39 New Zealand White rabbits by a transoral endoscopic technique. The animals were evaluated 3 weeks later with spiral CT, rigid bronchoscopy, and open laryngotracheal exploration. Spiral CT was performed with the location, degree, and length of subglottic stenosis being determined by a blinded observer. Each animal then underwent rigid bronchoscopy and open laryngotracheal exploration for determination of the same measurements. Data were analyzed to determine the correlation between the radiographic and surgical techniques in evaluating the airway stenosis. With regard to the degree of stenosis, 94% of the rabbits were determined to have CT and bronchoscopic measurements that were within 15% (Pearson correlation .94, p < .05). With regard to the length of stenosis, 94% of animals had a measurement on CT that was within 2 mm of that observed upon open exploration (Pearson correlation .81, p < .05). The CT evaluation of subglottic stenosis correlated well with the currently used method of visual inspection at bronchoscopy in evaluating tracheal stenosis in this animal model. These data suggest that CT could serve as a useful adjunct in the evaluation of tracheal stenosis, especially when serial examinations are required. PMID:10527273

Jewett, B S; Cook, R D; Johnson, K L; Logan, T C; Rosbe, K W; Mukherji, S K; Shockley, W W

1999-09-01

162

On the Upper Bound of the Prediction Accuracy of Residue Contacts in Proteins with Correlated Mutations: The Case Study of the Similarity Matrices  

NASA Astrophysics Data System (ADS)

Correlated mutations in proteins are believed to occur in order to preserve the protein functional folding through evolution. Their values can be deduced from sequence and/or structural alignments and are indicative of residue contacts in the protein three-dimensional structure. A correlation among pairs of residues is routinely evaluated with the Pearson correlation coefficient and the MCLACHLAN similarity matrix. In this paper, we describe an optimization procedure that maximizes the correlation between the Pearson coefficient and the protein residue contacts with respect to different similarity matrices, including random. Our results indicate that there is a large number of equivalent matrices that perform similarly to MCLACHLAN. We also obtain that the upper limit to the accuracy achievable in the prediction of the protein residue contacts is independent of the optimized similarity matrix. This suggests that poor scoring may be due to the choice of the linear correlation function in evaluating correlated mutations.

di Lena, Pietro; Fariselli, Piero; Margara, Luciano; Vassura, Marco; Casadio, Rita

163

Correlation of the NBME Advanced Clinical Examination in EM and the National EM M4 exams  

PubMed Central

Introduction Since 2011 two online, validated exams for fourth-year emergency medicine (EM) students have been available (National EM M4 Exams). In 2013 the National Board of Medical Examiners offered the Advanced Clinical Examination in Emergency Medicine (EM-ACE). All of these exams are now in widespread use; however, there are no data on how they correlate. This study evaluated the correlation between the EM-ACE exam and the National EM M4 Exams. Methods From May 2013 to April 2014 the EM-ACE and one version of the EM M4 exam were administered sequentially to fourth-year EM students at five U.S. medical schools. Data collected included institution, gross and scaled scores and version of the EM M4 exam. We performed Pearson’s correlation and random effects linear regression. Results 303 students took the EM-ACE and versions 1 (V1) or 2 (V2) of the EM M4 exams (279 and 24, respectively). The mean percent correct for the exams were as follows: EM-ACE 74.8 (SD-8.83), V1 83.0 (SD-6.41), V2 78.5 (SD-7.70). Pearson’s correlation coefficient for the V1/EM-ACE was 0.51 (0.42 scaled) and for the V2/EM-ACE was 0.59 (0.41 scaled). The coefficient of determination for V1/EM-ACE was 0.72 and for V2/EM-ACE = 0.71 (0.86 and 0.49 for scaled scores). The R-squared values were 0.25 and 0.30 (0.18 and 0.13, scaled), respectively. There was significant cluster effect by institution. Conclusion There was moderate positive correlation of student scores on the EM-ACE exam and the National EM M4 Exams.

Hiller, Katherine; Miller, Emily S.; Lawson, Luan; Wald, David; Beeson, Michael; Heitz, Corey; Morrissey, Thomas; House, Joseph; Poznanski, Stacey

2015-01-01

164

Gene differential coexpression analysis based on biweight correlation and maximum clique  

PubMed Central

Differential coexpression analysis usually requires the definition of 'distance' or 'similarity' between measured datasets. Until now, the most common choice is Pearson correlation coefficient. However, Pearson correlation coefficient is sensitive to outliers. Biweight midcorrelation is considered to be a good alternative to Pearson correlation since it is more robust to outliers. In this paper, we introduce to use Biweight Midcorrelation to measure 'similarity' between gene expression profiles, and provide a new approach for gene differential coexpression analysis. Firstly, we calculate the biweight midcorrelation coefficients between all gene pairs. Then, we filter out non-informative correlation pairs using the 'half-thresholding' strategy and calculate the differential coexpression value of gene, The experimental results on simulated data show that the new approach performed better than three previously published differential coexpression analysis (DCEA) methods. Moreover, we use the maximum clique analysis to gene subset included genes identified by our approach and previously reported T2D-related genes, many additional discoveries can be found through our method. PMID:25474074

2014-01-01

165

Optical correlation  

NASA Astrophysics Data System (ADS)

Pattern recognition may supplement or replace certain navigational aids on spacecraft in docking or landing activities. The need to correctly identify terrain features remains critical in preparation of autonomous planetary landing. One technique that may solve this problem is optical correlation. Correlation has been successfully demonstrated under ideal conditions; however, noise significantly affects the ability of the correlator to accurately identify input signals. Optical correlation in the presence of noise must be successfully demonstrated before this technology can be incorporated into system design. An optical correlator is designed and constructed using a modified 2f configuration. Liquid crystal televisions (LCTV) are used as the spatial light modulators (SLM) for both the input and filter devices. The filter LCTV is characterized and an operating curve is developed. Determination of this operating curve is critical for reduction of input noise. Correlation of live input with a programmable filter is demonstrated.

Cotariu, Steven S.

1991-12-01

166

Correlation methods  

NASA Technical Reports Server (NTRS)

A method for processing complex radar data with a computer using correlation functions is reviewed. Parameters including data storage, data reduction, and real time operation are addressed. Since complex auto- and cross-correlation functions are calculated and stored, almost no information is lost. These also can be analyzed in terms of the full correlation analysis of the spaced-antenna-drifts technique. The proposed approach therefore appears to be very feasible to suit most Mesosphere-Stratosphere-Troposphere (MST) radar applications.

Rottger, J.

1983-01-01

167

Application of One Sided t-tests and a Generalized Experiment Wise Error Rate to High-Density Oligonucleotide Microarray Experiments: An Example Using Arabidopsis.  

PubMed

MOTIVATION: A formidable challenge in the analysis of microarray data is the identification of those genes that exhibit differential expression. The objectives of this research were to examine the utility of simple ANOVA, one sided t tests, natural log transformation, and a generalized experiment wise error rate methodology for analysis of such experiments. As a test case, we analyzed a Affymetrix GeneChip microarray experiment designed to test for the effect of a CHD3 chromatin remodeling factor, PICKLE, and an inhibitor of the plant hormone gibberellin (GA), on the expression of 8256 Arabidopsis thaliana genes. RESULTS: The GFWER(k) is defined as the probability of rejecting k or more true null hypothesis at a given p level. Computing probabilities by GFWER(k) was shown to be simple to apply and, depending on the value of k, can greatly increase power. A k value as small as 2 or 3 was concluded to be adequate for large or small experiments respectively. A one sided t-test along with GFWER(2)=.05 identified 43 genes as exhibiting PICKLE-dependent expression. Expression of all 43 genes was re-examined by qRT-PCR, of which 36 (83.7%) were confirmed to exhibit PICKLE-dependent expression. PMID:20016750

Muir, W M; Romero-Severson, J; Rider, S D; Simons, A; Ogas, J

2006-01-01

168

Application of One Sided t-tests and a Generalized Experiment Wise Error Rate to High-Density Oligonucleotide Microarray Experiments: An Example Using Arabidopsis  

PubMed Central

Motivation A formidable challenge in the analysis of microarray data is the identification of those genes that exhibit differential expression. The objectives of this research were to examine the utility of simple ANOVA, one sided t tests, natural log transformation, and a generalized experiment wise error rate methodology for analysis of such experiments. As a test case, we analyzed a Affymetrix GeneChip microarray experiment designed to test for the effect of a CHD3 chromatin remodeling factor, PICKLE, and an inhibitor of the plant hormone gibberellin (GA), on the expression of 8256 Arabidopsis thaliana genes. Results The GFWER(k) is defined as the probability of rejecting k or more true null hypothesis at a given p level. Computing probabilities by GFWER(k) was shown to be simple to apply and, depending on the value of k, can greatly increase power. A k value as small as 2 or 3 was concluded to be adequate for large or small experiments respectively. A one sided t-test along with GFWER(2)=.05 identified 43 genes as exhibiting PICKLE-dependent expression. Expression of all 43 genes was re-examined by qRT-PCR, of which 36 (83.7%) were confirmed to exhibit PICKLE-dependent expression. PMID:20016750

Muir, W. M.; Romero-Severson, J.; Rider, S. D.; Simons, A.; Ogas, J.

2009-01-01

169

The 60- and 70-kDa heat-shock proteins and their correlation with cardiovascular risk factors in postmenopausal women with metabolic syndrome.  

PubMed

We investigated the association between circulating levels of 60 and 70 kDa heat-shock proteins (HSP60 and 70) and cardiovascular risk factors in postmenopausal women with or without metabolic syndrome (MetS). This cross-sectional study included 311 Brazilian women (age ?45 years with amenorrhea ?12 months). Women showing three or more of the following diagnostic criteria were diagnosed with MetS: waist circumference (WC) ?88 cm, blood pressure ?130/85 mmHg, triglycerides ?150 mg/dl, high-density lipoprotein (HDL) <50 mg/dl, and glucose ?100 mg/dl. Clinical, anthropometric, and biochemical parameters were collected. HSP60, HSP70, antibodies to HSP60 and HSP70, and C-reactive protein (CRP) levels were measured in serum. Student's t test, Kruskal-Wallis test, chi-square test, and Pearson correlation were used for statistical analysis. Of the 311 women, 30.9 % (96/311) were diagnosed with MetS. These women were, on average, obese with abdominal fat deposition and had lower HDL values as well as higher triglycerides and glucose levels. Homeostasis model assessment-insulin resistant (HOMA-IR) test values in these women were compatible with insulin resistance (P?correlation between anti-HSP70 and WC, blood pressure and HOMA-IR, and between CRP and WC, blood pressure, glucose, HOMA-IR, and triglycerides (P?

Nahas, Eliana A P; Nahas-Neto, Jorge; Orsatti, Claudio L; Tardivo, Ana Paula; Uemura, Gilberto; Peraçoli, Maria Terezinha S; Witkin, Steven S

2014-07-01

170

Correlation between Pediatric Balance Scale and Functional Test in Children with Cerebral Palsy  

PubMed Central

[Purpose] To investigate the correlation of functional balance with the functional performance of children with cerebral palsy. [Subjects and Methods] This was a cross-sectional study of children with cerebral palsy with mild to moderate impairment. The children were divided into 3 groups based on motor impairment. The evaluation consisted of the administration of the Pediatric Balance Scale (PBS) and the Pediatric Evaluation Disability Inventory. Correlations between the instruments were determined by calculating Pearson’s correlation coefficients. [Results] In Group 1, a strong positive correlation was found between the PBS and the mobility dimension of the Pediatric Evaluation Disability Inventory (r=0.82), and a moderate correlation was found between the PBS and self-care dimension of the Pediatric Evaluation Disability Inventory (r=0.51). In Group 2, moderate correlations were found between the PBS and both the self-care dimension (r=0.57) and mobility dimension (r=0.41) of the Pediatric Evaluation Disability Inventory. In Group 3, the PBS was weakly correlated with the self-care dimension (r=0.11) and moderately correlated with the mobility dimension (r=0.55). [Conclusion] The PBS proved to be a good auxiliary tool for the evaluation of functional performance with regard to mobility, but cannot be considered a predictor of function in children with cerebral palsy. PMID:25013281

Duarte, Natália de A. C.; Grecco, Luanda André Collange; Franco, Renata Calhes; Zanon, Nelci; Oliveira, Cláudia Santos

2014-01-01

171

Gaussian graphical modeling reveals specific lipid correlations in glioblastoma cells  

NASA Astrophysics Data System (ADS)

Advances in high-throughput measurements of biological specimens necessitate the development of biologically driven computational techniques. To understand the molecular level of many human diseases, such as cancer, lipid quantifications have been shown to offer an excellent opportunity to reveal disease-specific regulations. The data analysis of the cell lipidome, however, remains a challenging task and cannot be accomplished solely based on intuitive reasoning. We have developed a method to identify a lipid correlation network which is entirely disease-specific. A powerful method to correlate experimentally measured lipid levels across the various samples is a Gaussian Graphical Model (GGM), which is based on partial correlation coefficients. In contrast to regular Pearson correlations, partial correlations aim to identify only direct correlations while eliminating indirect associations. Conventional GGM calculations on the entire dataset can, however, not provide information on whether a correlation is truly disease-specific with respect to the disease samples and not a correlation of control samples. Thus, we implemented a novel differential GGM approach unraveling only the disease-specific correlations, and applied it to the lipidome of immortal Glioblastoma tumor cells. A large set of lipid species were measured by mass spectrometry in order to evaluate lipid remodeling as a result to a combination of perturbation of cells inducing programmed cell death, while the other perturbations served solely as biological controls. With the differential GGM, we were able to reveal Glioblastoma-specific lipid correlations to advance biomedical research on novel gene therapies.

Mueller, Nikola S.; Krumsiek, Jan; Theis, Fabian J.; Böhm, Christian; Meyer-Bäse, Anke

2011-06-01

172

Correlation Correlogram  

E-print Network

Network Correlation Neural Oscillator Correlogram CrossHair cell Cochlear Filtering Signal neural oscillators representing a single perceptual stream are synchronised, and are desynchronised from oscillator synchronisation. Model Overview Oscillator Array · Segment formation: excitatory and inhibitory

Wrigley, Stuart

173

Correlates of frailty among homeless adults.  

PubMed

Frailty, a relatively unexplored concept among vulnerable populations, may be a significant issue for homeless adults. This cross-sectional study assessed correlates of frailty among middle age and older homeless adults (N = 150, 40-73). A Pearson (r) bivariate correlation revealed a weak relationship between frailty and being female (r = .230, p < .01). Significant moderate negative correlations were found between frailty and resilience (r = -.395, p < .01), social support (r = -.377, p < .01), and nutrition (r = -.652, p < .01). Furthermore, Spearman's rho (r s) bivariate correlations revealed a moderate positive relationship between frailty and health care utilization (r(s) = .444, p < .01). A stepwise backward linear regression analysis was conducted and in the final model, age, gender, health care utilization, nutrition, and resilience were significantly related to frailty. Over the next two decades, there is an anticipated increase in the number of homeless adults which will necessitate a greater understanding of the needs of this hard-to-reach population. PMID:23676627

Salem, Benissa E; Nyamathi, Adeline M; Brecht, Mary-Lynn; Phillips, Linda R; Mentes, Janet C; Sarkisian, Catherine; Leake, Barbara

2013-10-01

174

Anatomic correlates of interhippocampal seizure propagation time.  

PubMed

The relation between interhippocampal seizure propagation time (IHSPT) and anatomic alterations in the human epileptic hippocampus may provide insight into the pathophysiology of temporal lobe epilepsy (TLE). Using depth electrode recordings, we measured the time required for spontaneous seizures with onset in one hippocampus to become manifest in the contralateral hippocampus in 50 patients who underwent resection of the temporal lobe of seizure origin. Cell densities in individual hippocampal subfields were determined and correlated with mean IHSPT for each patient. Mean IHSPT was significantly and inversely correlated with cell counts in CA4 only (r = -0.38, p less than 0.01, Pearson's product correlation; r = -0.52, p less than 0.001, Spearman's rank order correlation). In 5 patients with bilateral independent hippocampal seizure onset who had temporal lobectomy and a diagnosis of mesial temporal sclerosis, mean IHSPT was consistently longer from the sclerotic temporal lobe than to it. These observations suggest that anatomic changes associated with chronic epilepsy alter propagation patterns. Because CA4 is believed to modulate the output of dentate granule cells and also has commissural connections to the contralateral homotopic area, the association of decreased CA4 cells with prolongation of IHSPT suggests that the observed anatomic alterations may actively (through increased inhibition) or passively (through decreased recruitment) interfere with various routes of seizure propagation. PMID:1396429

Spencer, S S; Marks, D; Katz, A; Kim, J; Spencer, D D

1992-01-01

175

An anthropometric study to evaluate the correlation between the occlusal vertical dimension and length of the thumb  

PubMed Central

Background Establishment of proper occlusal vertical dimension (OVD) is one of the important tasks for successful prosthodontic therapy. An ideal method for determining OVD in terms of cost, time, and instrument requirements has been sought in prosthodontics by various investigators. However, no such single method has been formulated. In the current anthropometric study, the relationship of the length of the thumb to the OVD was tested in two ethnic groups of Nepal, Aryans, and Mongoloids. The result of this study can be useful in determining proper OVD in edentulous patients. Aims and objectives The primary aim of the present study was to evaluate the correlation between the length of the thumb and OVD in Aryan and Mongoloid ethnic groups. The secondary aim was to compare the correlation between OVD and other anatomic measurements (eye–ear distance and pupil-to-rima oris distance) in these ethnicities. Materials and methods The OVD, thumb length, eye–ear distance and distance between pupil of eye and rima oris were measured in a total of 500 adult dentulous volunteers. The correlation between OVD and thumb length as well as other anatomic measurements was checked with Pearson’s product moment correlation coefficient. Linear regression analysis was performed to determine the relationship of OVD to the length of the thumb. Results The thumb length was significantly (P?0.05) correlated with strong and positive values (Pearson’s coefficient =0.874 in the whole population, 0.826 in Aryans, and 0.944 in Mongoloids). Regression analysis showed that thumb length was significantly related to OVD in both ethnic groups. Conclusion Within the limitations of the present study, the result implies that thumb length can be used as an adjunct for establishing OVD in the edentulous patients.

Basnet, Bishal Babu; Parajuli, Prakash Kumar; Singh, Raj Kumar; Suwal, Pramita; Shrestha, Pragya; Baral, Dharanidhar

2015-01-01

176

Estimating membrane voltage correlations from extracellular spike trains.  

PubMed

The cross-correlation coefficient between neural spike trains is a commonly used tool in the study of neural interactions. Two well-known complications that arise in its interpretation are 1) modulations in the correlation coefficient may result solely from changes in the mean firing rate of the cells and 2) the mean firing rates of the neurons impose upper and lower bounds on the correlation coefficient whose absolute values differ by an order of magnitude or more. Here, we propose a model-based approach to the interpretation of spike train correlations that circumvents these problems. The basic idea of our proposal is to estimate the cross-correlation coefficient between the membrane voltages of two cells from their extracellular spike trains and use the resulting value as the degree of correlation (or association) of neural activity. This is done in the context of a model that assumes the membrane voltages of the cells have a joint normal distribution and spikes are generated by a simple thresholding operation. We show that, under these assumptions, the estimation of the correlation coefficient between the membrane voltages reduces to the calculation of a tetrachoric correlation coefficient (a measure of association in nominal data introduced by Karl Pearson) on a contingency table calculated from the spike data. Simulations of conductance-based leaky integrate-and-fire neurons indicate that, despite its simplicity, the technique yields very good estimates of the intracellular membrane voltage correlation from the extracellular spike trains in biologically realistic models. PMID:12686584

Dorn, Jessy D; Ringach, Dario L

2003-04-01

177

Correlative tomography.  

PubMed

Increasingly researchers are looking to bring together perspectives across multiple scales, or to combine insights from different techniques, for the same region of interest. To this end, correlative microscopy has already yielded substantial new insights in two dimensions (2D). Here we develop correlative tomography where the correlative task is somewhat more challenging because the volume of interest is typically hidden beneath the sample surface. We have threaded together x-ray computed tomography, serial section FIB-SEM tomography, electron backscatter diffraction and finally TEM elemental analysis all for the same 3D region. This has allowed observation of the competition between pitting corrosion and intergranular corrosion at multiple scales revealing the structural hierarchy, crystallography and chemistry of veiled corrosion pits in stainless steel. With automated correlative workflows and co-visualization of the multi-scale or multi-modal datasets the technique promises to provide insights across biological, geological and materials science that are impossible using either individual or multiple uncorrelated techniques. PMID:24736640

Burnett, T L; McDonald, S A; Gholinia, A; Geurts, R; Janus, M; Slater, T; Haigh, S J; Ornek, C; Almuaili, F; Engelberg, D L; Thompson, G E; Withers, P J

2014-01-01

178

Correlative Tomography  

NASA Astrophysics Data System (ADS)

Increasingly researchers are looking to bring together perspectives across multiple scales, or to combine insights from different techniques, for the same region of interest. To this end, correlative microscopy has already yielded substantial new insights in two dimensions (2D). Here we develop correlative tomography where the correlative task is somewhat more challenging because the volume of interest is typically hidden beneath the sample surface. We have threaded together x-ray computed tomography, serial section FIB-SEM tomography, electron backscatter diffraction and finally TEM elemental analysis all for the same 3D region. This has allowed observation of the competition between pitting corrosion and intergranular corrosion at multiple scales revealing the structural hierarchy, crystallography and chemistry of veiled corrosion pits in stainless steel. With automated correlative workflows and co-visualization of the multi-scale or multi-modal datasets the technique promises to provide insights across biological, geological and materials science that are impossible using either individual or multiple uncorrelated techniques.

Burnett, T. L.; McDonald, S. A.; Gholinia, A.; Geurts, R.; Janus, M.; Slater, T.; Haigh, S. J.; Ornek, C.; Almuaili, F.; Engelberg, D. L.; Thompson, G. E.; Withers, P. J.

2014-04-01

179

Correlation spectrometer  

DOEpatents

A correlation spectrometer can detect a large number of gaseous compounds, or chemical species, with a species-specific mask wheel. In this mode, the spectrometer is optimized for the direct measurement of individual target compounds. Additionally, the spectrometer can measure the transmission spectrum from a given sample of gas. In this mode, infrared light is passed through a gas sample and the infrared transmission signature of the gasses present is recorded and measured using Hadamard encoding techniques. The spectrometer can detect the transmission or emission spectra in any system where multiple species are present in a generally known volume.

Sinclair, Michael B. (Albuquerque, NM); Pfeifer, Kent B. (Los Lunas, NM); Flemming, Jeb H. (Albuquerque, NM); Jones, Gary D. (Tijeras, NM); Tigges, Chris P. (Albuquerque, NM)

2010-04-13

180

Closure and ratio correlation analysis of lunar chemical and grain size data  

NASA Technical Reports Server (NTRS)

Major element and major element plus trace element analyses were selected from the lunar data base for Apollo 11, 12 and 15 basalt and regolith samples. Summary statistics for each of the six data sets were compiled, and the effects of closure on the Pearson product moment correlation coefficient were investigated using the Chayes and Kruskal approximation procedure. In general, there are two types of closure effects evident in these data sets: negative correlations of intermediate size which are solely the result of closure, and correlations of small absolute value which depart significantly from their expected closure correlations which are of intermediate size. It is shown that a positive closure correlation will arise only when the product of the coefficients of variation is very small (less than 0.01 for most data sets) and, in general, trace elements in the lunar data sets exhibit relatively large coefficients of variation.

Butler, J. C.

1976-01-01

181

Emotional structure and commitment: implications for health care management  

Microsoft Academic Search

Purpose – This paper aims to determine if the emotional structure of direct healthcare workers was related to their commitment to the organization. Design\\/methodology\\/approach – A total of 105 direct healthcare workers completed self-report surveys to determine their emotional intelligence, emotional coping ability, and affective organizational commitment. Pearson Product Moment Correlation and independent sample t tests were used to analyze

John Humphreys; Bill Brunsen; Dale Davis

2005-01-01

182

Type II Robustness of H0: Rho=0 for Non-Normal Distributions  

ERIC Educational Resources Information Center

Is the t test statistic for the Pearson Product Moment Correlation Coefficient robust to errors of the second kind? This investigation indirectly measured the effects of power through a type 2 error rate robustness study. The results were revealing. [The dissertation citations contained here are published with the permission of ProQuest LLC.…

Wren, Stephanie D.

2010-01-01

183

Substance Abuse Counselors and Moral Reasoning: Hypothetical and Authentic Dilemmas  

ERIC Educational Resources Information Center

This exploratory study examined the assumption that the level of moral reasoning (Defining Issues Test; J. R. Rest, 1986) used in solving hypothetical and authentic dilemmas is similar for substance abuse counselors (N = 188). The statistical analyses used were paired-sample t tests, Pearson product-moment correlation, and simultaneous multiple…

Sias, Shari M.

2009-01-01

184

Inferring correlation networks from genomic survey data.  

PubMed

High-throughput sequencing based techniques, such as 16S rRNA gene profiling, have the potential to elucidate the complex inner workings of natural microbial communities - be they from the world's oceans or the human gut. A key step in exploring such data is the identification of dependencies between members of these communities, which is commonly achieved by correlation analysis. However, it has been known since the days of Karl Pearson that the analysis of the type of data generated by such techniques (referred to as compositional data) can produce unreliable results since the observed data take the form of relative fractions of genes or species, rather than their absolute abundances. Using simulated and real data from the Human Microbiome Project, we show that such compositional effects can be widespread and severe: in some real data sets many of the correlations among taxa can be artifactual, and true correlations may even appear with opposite sign. Additionally, we show that community diversity is the key factor that modulates the acuteness of such compositional effects, and develop a new approach, called SparCC (available at https://bitbucket.org/yonatanf/sparcc), which is capable of estimating correlation values from compositional data. To illustrate a potential application of SparCC, we infer a rich ecological network connecting hundreds of interacting species across 18 sites on the human body. Using the SparCC network as a reference, we estimated that the standard approach yields 3 spurious species-species interactions for each true interaction and misses 60% of the true interactions in the human microbiome data, and, as predicted, most of the erroneous links are found in the samples with the lowest diversity. PMID:23028285

Friedman, Jonathan; Alm, Eric J

2012-01-01

185

Decline in lumbar extensor muscle strength the older adults: correlation with age, gender and spine morphology  

PubMed Central

Background Muscle morphology, age and gender may be determinants of muscle strength in older adults. However, very few research studies have directly examined such correlation in the ageing spine. The aim of the study was to examine the correlation between lumbar extensor muscle strength, its muscle fibre angles, thoracolumbar curvature, age and gender in the older and younger adults. Methods Muscle fibre angles of lumbar extensor muscles, thoracolumbar curvature and lumbar extensor muscle strength were examined in 26 young (mean age 27.9, SD 5.2) and 26 older (mean age 72.1, SD 5.9) participants. Pearson’s correlation was employed to determine the association among lumbar extensor muscle fibre angle, thoracolumbar curvature, age, gender and lumbar extensor muscle strength. Multiple stepwise linear regression analysis was used to identify significant determinants of lumbar extensor muscle strength. Results The results demonstrated a significant correlation between lumbar extensor muscle strength, muscle fibre angle, age and gender. In the step wise regression analysis, both gender and age were identified as the most robust determinant for lumbar extensor muscle strength in older adults. However, gender was the only determinant of muscle strength in the young. Conclusion These results suggest that the decline in the lumbar extensor muscle strength in older adults was more dependent on age when compared to younger adults. PMID:23875830

2013-01-01

186

Spatial correlation structure of monthly rainfall at a mesoscale region of north-eastern Bohemia  

NASA Astrophysics Data System (ADS)

The spatial correlation structure of monthly rainfall was analysed using data from 38 rain gauges located in north-eastern Bohemia. Three different inter-station correlation measures—Pearson's correlation coefficient, Spearman's rank-order correlation coefficient and Kendall's tau rank correlation coefficient—were estimated using monthly rainfall records from a recent 31-year period. Six different theoretical parametric correlation models were identified using the nonlinear least squares method. The spatial correlation structure was described using the fitted parameters. Comparison of estimated correlation models showed that, as measured by standard error, the best fitted was a two-parameter exponential model. The relationships between parameters of the exponential two-parameter model were further explored and described. The temporal variability of correlation showed trends in the fitted parameters over the studied period. On a seasonal basis, the correlation between the stations was stronger in autumn and winter than in spring and summer. The spatial variability of estimated parameters revealed that parameters of Matérn and two-parameter exponential models were dependent on altitude.

Svoboda, Vojt?ch; Máca, Petr; Hanel, Martin; Pech, Pavel

2014-08-01

187

Spatial-temporal current source correlations and cortical connectivity.  

PubMed

The purpose of this study was to explore spatial-temporal correlations between 3-dimensional current density estimates using Low Resolution Electromagnetic Tomography (LORETA). The electroencephalogram (EEG) was recorded from 19 scalp locations from 97 subjects. LORETA current density was computed for 2,394 gray matter pixels. The gray matter pixels were grouped into 33 left hemisphere and 33 right hemisphere regions of interest (ROIs) based on groupings of Brodmann areas. The average source current density in a given region of interest (ROI) was computed for each 2 second epoch of EEG and then a Pearson product correlation coefficient was computed over the time series of successive 2 second epochs of current density between all pairwise combinations of ROIs during the resting eyes-closed EEG session. Rhythmic changes in source correlation as a function of distance were present in all regions of interest. Also, maximum correlations at certain frequencies were present independent of distance. The occipital regions exhibited the highest short distance correlations and the frontal regions exhibited the highest long distance correlations. In general, the right hemisphere exhibited higher intra-hemispheric source correlations than the left hemisphere especially in the temporal, parietal and occipital cortex. The strongest left vs. right hemisphere differences were in the alpha frequency band (8-12 Hz) and in the gamma frequency band (37-40 Hz). The pattern of spatial frequencies in different cortical lobules is consistent with differences in neural packing density and the operation of 'U' shaped fiber systems. The general conclusions were: 1--the higher the packing density then the greater the intra-cortical connection contribution to LORETA source correlations, 2--spatial frequencies are primarily due to intra-cortical 'U' shaped fiber connections and long distance fiber connections, 3--posterior and temporal cortical intra-hemispheric coupling is generally stronger in the right hemisphere than in the left hemisphere. PMID:17319590

Thatcher, R W; Biver, C J; North, D

2007-01-01

188

Late Holocene earthquake history of the Brigham City segment of the Wasatch fault zone at the Hansen Canyon, Kotter Canyon, and Pearsons Canyon trench sites, Box Elder County, Utah  

USGS Publications Warehouse

Of the five central segments of the Wasatch fault zone (WFZ) having evidence of recurrent Holocene surface-faulting earthquakes, the Brigham City segment (BCS) has the longest elapsed time since its most recent surface-faulting event (~2.1 kyr) compared to its mean recurrence time between events (~1.3 kyr). Thus, the BCS has the highest time-dependent earthquake probability of the central WFZ. We excavated trenches at three sites––the Kotter Canyon and Hansen Canyon sites on the north-central BCS and Pearsons Canyon site on the southern BCS––to determine whether a surface-faulting earthquake younger than 2.1 ka occurred on the BCS. Paleoseismic data for Hansen Canyon and Kotter Canyon confirm that the youngest earthquake on the north-central BCS occurred before 2 ka, consistent with previous north-central BCS investigations at Bowden Canyon and Box Elder Canyon. At Hansen Canyon, the most recent earthquake is constrained to 2.1–4.2 ka and had 0.6–2.5 m of vertical displacement. At Kotter Canyon, we found evidence for two events at 2.5 ± 0.3 ka and 3.5 ± 0.3 ka, with an average displacement per event of 1.9–2.3 m. Paleoseismic data from Pearsons Canyon, on the previously unstudied southern BCS, indicate that a post-2 ka earthquake ruptured this part of the segment. The Pearsons Canyon earthquake occurred at 1.2 ± 0.04 ka and had 0.1–0.8 m of vertical displacement, consistent with our observation of continuous, youthful scarps on the southern 9 km of the BCS having 1–2 m of late Holocene(?) surface offset. The 1.2-ka earthquake on the southern BCS likely represents rupture across the Weber–Brigham City segment boundary from the penultimate Weber-segment earthquake at about 1.1 ka. The Pearsons Canyon data result in a revised length of the BCS that has not ruptured since 2 ka (with time-dependent probability implications), and provide compelling evidence of at least one segment-boundary failure and multi-segment rupture on the central WFZ. Our paleoseismic investigations of the BCS clarify the timing, displacement, and extent of late Holocene earthquakes on the segment, and importantly, confirm the long elapsed time since the most recent earthquake on most of the BCS.

DuRoss, Christopher B.; Personius, Stephen F.; Crone, Anthony J.; McDonald, Greg N.; Briggs, Richard W.

2012-01-01

189

Diversity of the Vaginal Microbiome Correlates With Preterm Birth  

PubMed Central

Reproductive tract infection is a major initiator of preterm birth (PTB). The objective of this prospective cohort study of 88 participants was to determine whether PTB correlates with the vaginal microbiome during pregnancy. Total DNA was purified from posterior vaginal fornix swabs during gestation. The 16S ribosomal RNA gene was amplified using polymerase chain reaction primers, followed by chain-termination sequencing. Bacteria were identified by comparing contig consensus sequences with the Ribosomal Database Project. Dichotomous responses were summarized via proportions and continuous variables via means ± standard deviation. Mean Shannon Diversity index differed by Welch t test (P = .00016) between caucasians with PTB and term gestation. Species diversity was greatest among African Americans (P = .0045). Change in microbiome/Lactobacillus content and presence of putative novel/noxious bacteria did not correlate with PTB. We conclude that uncultured vaginal bacteria play an important role in PTB and race/ethnicity and sampling location are important determinants of the vaginal microbiome. PMID:23715799

Hyman, Richard W.; Fukushima, Marilyn; Jiang, Hui; Fung, Eula; Rand, Larry; Johnson, Brittni; Vo, Kim Chi; Caughey, Aaron B.; Hilton, Joan F.; Davis, Ronald W.; Giudice, Linda C.

2014-01-01

190

YKL-40 in Asthma and its correlation with different clinical parameters.  

PubMed

It has been suggested that elevated serum level of YKL-40 could be a marker for asthma and its severity. Along with few published studies, we investigated its correlation with asthma and its severity as well as spirometric indices.114 patients with asthma and 114 healthy controls underwent the assessment of serum level of YKL-40 (by ELISA) and spirometric indices. Pearson's coefficient determined the correlation between the variables and multivariate linear regression analysis was used for adjusting the effect of different probable confounding factors.Serum levels of YKL-40 were significantly higher in the asthmatic patients compared to those in healthy people (p<0.001). We also found a significant correlation between YKL-40 serum level and spirometric indices even after adjusting the effects of other variables.We report for the first time in an Iranian population that YKL-40 may be a good diagnostic marker of asthma in serum. PMID:24659163

Saba, Mohammadali; Sharif, Mohammad Reza; Akbari, Hossein; Nikoueinejad, Hassan; Ramazani Jolfaii, Maryam

2014-08-01

191

Filtering induces correlation in fMRI resting state data.  

PubMed

Correlation-based functional MRI connectivity methods typically impose a temporal sample independence assumption on the data. However, the conventional use of temporal filtering to address the high noise content of fMRI data may introduce sample dependence. Violation of the independence assumption has ramifications for the distribution of sample correlation which, if unaccounted for, may invalidate connectivity results. To enable the use of temporal filtering for noise suppression while maintaining the integrity of connectivity results, we derive the distribution of sample correlation between filtered timeseries as a function of the filter frequency response. Corrected distributions are also derived for statistical inference tests of sample correlation between filtered timeseries, including Fisher's z-transformation and the Student's t-test. Crucially, the proposed corrections are valid for any unknown true correlation and arbitrary filter specifications. Empirical simulations demonstrate the potential for temporal filtering to artificially induce connectivity by introducing sample dependence, and verify the utility of the proposed corrections in mitigating this effect. The importance of our corrections is exemplified in a resting state fMRI connectivity analysis: seed-voxel correlation maps generated from filtered data using uncorrected test variates yield an unfeasible number of connections to the left primary motor cortex, suggesting artificially induced connectivity, while maps acquired from filtered data using corrected test variates exhibit bilateral connectivity in the primary motor cortex, in conformance with expected results as seen in the literature. PMID:22939874

Davey, Catherine E; Grayden, David B; Egan, Gary F; Johnston, Leigh A

2013-01-01

192

Mucocutaneous Manifestations of HIV and the Correlation with WHO Clinical Staging in a Tertiary Hospital in Nigeria  

PubMed Central

Skin diseases are indicators of HIV/AIDS which correlates with WHO clinical stages. In resource limited environment where CD4 count is not readily available, they can be used in assessing HIV patients. The study aims to determine the mucocutaneous manifestations in HIV positive patients and their correlation with WHO clinical stages. A prospective cross-sectional study of mucocutaneous conditions was done among 215 newly diagnosed HIV patients from June 2008 to May 2012 at adult ART clinic, Wesley Guild Hospital Unit, OAU Teaching Hospitals Complex, Ilesha, Osun State, Nigeria. There were 156 dermatoses with oral/oesophageal/vaginal candidiasis (41.1%), PPE (24.4%), dermatophytic infections (8.9%), and herpes zoster (3.8%) as the most common dermatoses. The proportions of dermatoses were 4.5%, 21.8%, 53.2%, and 20.5% in stages 1–4, respectively. A significant relationship (using Pearson's Chi square with P value <0.05) was obtained between dermatoses and WHO clinical stages. Pearson's correlation coefficient showed a positive correlation between the number of dermatoses and the WHO clinical stages. Dermatoses can therefore serve as diagnostic and prognostic markers in resource limited settings to initiate HAART in clinical stages 3 and 4. PMID:25587439

Oninla, Olumayowa Abimbola

2014-01-01

193

Time domain measures of inter-channel EEG correlations: a comparison of linear, nonparametric and nonlinear measures.  

PubMed

Correlations between ten-channel EEGs obtained from thirteen healthy adult participants were investigated. Signals were obtained in two behavioral states: eyes open no task and eyes closed no task. Four time domain measures were compared: Pearson product moment correlation, Spearman rank order correlation, Kendall rank order correlation and mutual information. The psychophysiological utility of each measure was assessed by determining its ability to discriminate between conditions. The sensitivity to epoch length was assessed by repeating calculations with 1, 2, 3, …, 8 s epochs. The robustness to noise was assessed by performing calculations with noise corrupted versions of the original signals (SNRs of 0, 5 and 10 dB). Three results were obtained in these calculations. First, mutual information effectively discriminated between states with less data. Pearson, Spearman and Kendall failed to discriminate between states with a 1 s epoch, while a statistically significant separation was obtained with mutual information. Second, at all epoch durations tested, the measure of between-state discrimination was greater for mutual information. Third, discrimination based on mutual information was more robust to noise. The limitations of this study are discussed. Further comparisons should be made with frequency domain measures, with measures constructed with embedded data and with the maximal information coefficient. PMID:24465281

Bonita, J D; Ambolode, L C C; Rosenberg, B M; Cellucci, C J; Watanabe, T A A; Rapp, P E; Albano, A M

2014-02-01

194

Correlation between Pediatric Balance Scale and Functional Test in Children with Cerebral Palsy.  

PubMed

[Purpose] To investigate the correlation of functional balance with the functional performance of children with cerebral palsy. [Subjects and Methods] This was a cross-sectional study of children with cerebral palsy with mild to moderate impairment. The children were divided into 3 groups based on motor impairment. The evaluation consisted of the administration of the Pediatric Balance Scale (PBS) and the Pediatric Evaluation Disability Inventory. Correlations between the instruments were determined by calculating Pearson's correlation coefficients. [Results] In Group 1, a strong positive correlation was found between the PBS and the mobility dimension of the Pediatric Evaluation Disability Inventory (r=0.82), and a moderate correlation was found between the PBS and self-care dimension of the Pediatric Evaluation Disability Inventory (r=0.51). In Group 2, moderate correlations were found between the PBS and both the self-care dimension (r=0.57) and mobility dimension (r=0.41) of the Pediatric Evaluation Disability Inventory. In Group 3, the PBS was weakly correlated with the self-care dimension (r=0.11) and moderately correlated with the mobility dimension (r=0.55). [Conclusion] The PBS proved to be a good auxiliary tool for the evaluation of functional performance with regard to mobility, but cannot be considered a predictor of function in children with cerebral palsy. PMID:25013281

Duarte, Natália de A C; Grecco, Luanda André Collange; Franco, Renata Calhes; Zanon, Nelci; Oliveira, Cláudia Santos

2014-06-01

195

Correlation of PET Images of Metabolism, Proliferation and Hypoxia to Characterize Tumor Phenotype in Patients with Cancer of the Oropharynx  

PubMed Central

Spatial organization of tumor phenotype is of great interest to radiotherapy target definition and outcome prediction. We characterized tumor phenotype in patients with cancers of the oropharynx through voxel-based correlation of PET images of metabolism, proliferation, and hypoxia. Methods Patients with oropharyngeal cancer received 18F-fluorodeoxyglucose (FDG) PET/CT, 18F-fluorothymidine (FLT) PET/CT, and 61Cu-diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) PET/CT. Images were co-registered and standardized uptake values (SUV) were calculated for all modalities. Voxel-based correlation was evaluated with Pearson’s correlation coefficient in tumor regions. Additionally, sensitivity studies were performed to quantify the effects of image segmentation, registration, noise, and segmentation on R. Results On average, FDG PET and FLT PET images were most highly correlated (RFDG:FLT=0.76, range 0.53–0.85), while Cu-ATSM PET showed greater heterogeneity in correlation to other tracers (RFDG:Cu-ATSM=0.64, range 0.51–0.79; RFLT:Cu-ATSM=0.61, range 0.21–0.80). Of the tested parameters, correlation was most sensitive to image registration. Misregistration of one voxel lead to ?RFDG=0.25, ?RFLT=0.39, and ?RCu-ATSM=0.27. Image noise and reconstruction also had quantitative effects on correlation. No significant quantitative differences were found between GTV, expanded GTV, or CTV regions. Conclusions Voxel-based correlation represents a first step into understanding spatial organization of tumor phenotype. These results have implications for radiotherapy target definition and provide a framework to test outcome prediction based on pretherapy distribution of phenotype. PMID:23068711

Nyflot, Matthew J; Harari, Paul M; Yip, Stephen; Perlman, Scott B; Jeraj, Robert

2012-01-01

196

Correlation of idiopathic scoliosis assessments between newly developed Milwaukee Topographic Scanner and Quantec.  

PubMed

The Milwaukee Topographic Scanner (MTS) is a newly developed system, which utilizes laser technology to obtain three-dimensional topographic evaluation of the spine. The goal of this study was to determine the correlation of topographic measurements between MTS and Quantec Spinal Imaging System. Twelve parameters generated by the MTS and Quantec Spinal Imaging System was compared to each other using the Pearson Coefficient. Twenty patients between the ages 16-18 with scoliosis were evaluated with the MTS and Quantec. There were several parameters, which showed high correlations especially back height (0.972), coronal curve (0.952), and left trunk volume (0.905). MTS is a reliable three-dimensional topographic alternative to radiographs without the exposure to radiation. PMID:22744503

Lim, C H; Tassone, C; Liu, X C; Thometz, J G; Lyon, R

2012-01-01

197

The SNAP Index Does Not Correlate with the State Behavioral Scale in Intubated and Sedated Children  

PubMed Central

Background Ensuring appropriate levels of sedation for critically ill children is integral to pediatric critical care. Traditionally, clinicians have used subjective scoring tools to assess sedation levels. The SNAP II uses dual frequency processed electroencephalography to evaluate brain activity and may provide an objective assessment of sedation levels. Objective This study attempts to find an objective method to monitor sedation in critically ill pediatric patients. We compared the SNAP II, a processed electroencephalography device, with the State Behavioral Scale (SBS), a subjective sedation scoring tool. We hypothesize that the SNAP II correlates with the SBS and has less observer bias. Methods This was an IRB approved prospective, observational study. Patients receiving intravenous sedation while being mechanically ventilated were enrolled after informed consent. After the SNAP II monitoring electrodes were attached, blinded bedside nurses assessed sedation levels using the SBS. SNAP indices were collected and compared with SBS scores to determine correlation. Results We compared 417 paired data points from 15 patients using Pearson's correlation and Least Squares Means to determine correlation between the SBS and SNAP indices. No correlation was observed. Using covariance model patterning for repeated measures to adjust for covariates again showed no correlation. Conclusion The SNAP index does not correlate with SBS scores in our PICU. Its use cannot be recommended to measure levels of sedation in our population. Future research should continue to explore objective ways of measuring sedation in critically ill children. PMID:24103039

Thompson, Cecilia; Shabanova, Veronika; Giuliano, John S.

2013-01-01

198

Degree Correlations in Directed Scale-Free Networks  

PubMed Central

Scale-free networks, in which the distribution of the degrees obeys a power-law, are ubiquitous in the study of complex systems. One basic network property that relates to the structure of the links found is the degree assortativity, which is a measure of the correlation between the degrees of the nodes at the end of the links. Degree correlations are known to affect both the structure of a network and the dynamics of the processes supported thereon, including the resilience to damage, the spread of information and epidemics, and the efficiency of defence mechanisms. Nonetheless, while many studies focus on undirected scale-free networks, the interactions in real-world systems often have a directionality. Here, we investigate the dependence of the degree correlations on the power-law exponents in directed scale-free networks. To perform our study, we consider the problem of building directed networks with a prescribed degree distribution, providing a method for proper generation of power-law-distributed directed degree sequences. Applying this new method, we perform extensive numerical simulations, generating ensembles of directed scale-free networks with exponents between 2 and 3, and measuring ensemble averages of the Pearson correlation coefficients. Our results show that scale-free networks are on average uncorrelated across directed links for three of the four possible degree-degree correlations, namely in-degree to in-degree, in-degree to out-degree, and out-degree to out-degree. However, they exhibit anticorrelation between the number of outgoing connections and the number of incoming ones. The findings are consistent with an entropic origin for the observed disassortativity in biological and technological networks. PMID:25310101

Williams, Oliver; Del Genio, Charo I.

2014-01-01

199

Underestimating Correlation from Scatterplots.  

ERIC Educational Resources Information Center

Eighty graduate students and faculty estimated the correlation coefficient for each of 13 computer-printed scatterplots. As predicted, subjects underestimated the degree of actual correlation. With substantial moderation by a method-of-presentation factor, this underestimation was most pronounced in the middle of the correlational range.…

Strahan, Robert F.; Hansen, Chris J.

1979-01-01

200

Reverse Correlation in Neurophysiology  

ERIC Educational Resources Information Center

This article presents a review of reverse correlation in neurophysiology. We discuss the basis of reverse correlation in linear transducers and in spiking neurons. The application of reverse correlation to measure the receptive fields of visual neurons using white noise and m-sequences, and classical findings about spatial and color processing in…

Ringach, Dario; Shapley, Robert

2004-01-01

201

Correlation between lidar-derived intensity and passive optical imagery  

NASA Astrophysics Data System (ADS)

When LiDAR data are collected, the intensity information is recorded for each return, and can be used to produce an image resembling those acquired by passive imaging sensors. This research evaluated LiDAR intensity data to determine its potential for use as baseline imagery where optical imagery are unavailable. Two airborne LiDAR datasets collected at different point densities and laser wavelengths were gridded and compared with optical imagery. Optech Orion C200 laser data were compared with a corresponding 1541 nm spectral band from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). Optech ALTM Gemini LiDAR data collected at 1064 nm were compared to the WorldView-2 (WV-2) 949 - 1043 nm NIR2 band. Intensity images were georegistered and spatially resampled to match the optical data. The Pearson Product Moment correlation coefficient was calculated between datasets to determine similarity. Comparison for the full LiDAR datasets yielded correlation coefficients of approximately 0.5. Because LiDAR returns from vegetation are known to be highly variable, a Normalized Difference Vegetation Index (NDVI) was calculated utilizing the optical imagery, and intensity and optical imagery were separated into vegetation and nonvegetation categories. Comparison of the LiDAR intensity for non-vegetated areas to the optical imagery yielded coefficients greater than 0.9. These results demonstrate that LiDAR intensity data may be useful in substituting for optical imagery where only LiDAR is available.

Metcalf, Jeremy P.; Kim, Angela M.; Kruse, Fred A.; Olsen, Richard C.

2014-06-01

202

Temporal patterns of self-injurious behavior correlate with stress hormone levels in the developmentally disabled  

PubMed Central

While the origins and developmental course of self-injurious behavior (SIB) remain relatively unknown, recent studies suggest a biological imbalance may potentiate or provoke the contagious recurrence of SIB patterns in individuals with severe developmental disabilities (DD). Evidence from several laboratories indicates that functioning, relations, and processing of a stress-related molecule, proopiomelanocortin, (POMC), may be perturbed among certain subgroups of individuals exhibiting SIB. The current investigation employed a unique time-pattern analysis program (THEME) to examine whether recurrent temporal patterns (T-patterns) of SIB were related to morning levels of two POMC-derived hormones: ?-endorphin (?E) and adrenocorticotropic hormone (ACTH). THEME was used to quantify highly significant (nonrandom) T-patterns that included SIB within a dataset of in-situ observational recordings spanning 8 days (~40 hours) in 25 subjects with DD. Pearson’s product-moment analyses revealed highly significant correlations between the percentage of T-patterns containing SIB and basal levels of both ?E and ACTH, which were not found with any other “control” T-patterns. These findings support the hypothesis that the recurrent temporal patterning of SIB represents a unique behavioral phenotype directly related to perturbed levels of POMC-derived stress hormones in certain individuals with severe DD. PMID:17913241

Kemp, Aaron S.; Fillmore, Paul T.; Lenjavi, Mohammed R.; Lyon, Melvin; Chicz-DeMet, Aleksandra; Touchette, Paul E.; Sandman, Curt A.

2007-01-01

203

Correlation of Space Shuttle Landing Performance with Post-Flight Cardiovascular Dysfunction  

NASA Technical Reports Server (NTRS)

Introduction: Microgravity induces cardiovascular adaptations resulting in orthostatic intolerance on re-exposure to normal gravity. Orthostasis could interfere with performance of complex tasks during the re-entry phase of Shuttle landings. This study correlated measures of Shuttle landing performance with post-flight indicators of orthostatic intolerance. Methods: Relevant Shuttle landing performance parameters routinely recorded at touchdown by NASA included downrange and crossrange distances, airspeed, and vertical speed. Measures of cardiovascular changes were calculated from operational stand tests performed in the immediate post-flight period on mission commanders from STS-41 to STS-66. Stand test data analyzed included maximum standing heart rate, mean increase in maximum heart rate, minimum standing systolic blood pressure, and mean decrease in standing systolic blood pressure. Pearson correlation coefficients were calculated with the null hypothesis that there was no statistically significant linear correlation between stand test results and Shuttle landing performance. A correlation coefficient? 0.5 with a p<0.05 was considered significant. Results: There were no significant linear correlations between landing performance and measures of post-flight cardiovascular dysfunction. Discussion: There was no evidence that post-flight cardiovascular stand test data correlated with Shuttle landing performance. This implies that variations in landing performance were not due to space flight-induced orthostatic intolerance.

McCluskey, R.

2004-01-01

204

Diffusion tensor imaging of neural tissue organization: correlations between radiologic and histologic parameters.  

PubMed

This study examined the relationship between histological variables and diffusion tensor imaging (DTI) values in a normal canine brain. We hypothesized that radial diffusivity (RD) would correlate with myelin density and fractional anisotropy (FA) would correlate with white matter fiber coherence. We acquired DTI maps of a normal canine brain post mortem on a 7T MR scanner (TR = 100 ms, TE = 18.1 ms, NEX = 1, width [d] = 4 ms, separation [D] = 8.9 ms, gradient amplitude = 600 mT/m, b=1,565 s/mm(2)) and generated maps of FA, RD, and axial diffusivity. The brain was subsequently sectioned and stained for myelin with gold chloride, which also allowed for measurement of fiber coherence. DTI metrics were then directly compared with the optical density of the myelin stain and the coherence of stained fibers. Multivariate linear regression demonstrated that RD, but not FA, significantly correlated with both myelin stain intensity (p = 0.031) and fiber coherence (p = 0.035). The Pearson correlation coefficient between these two histological variables and FA was 0.122; and was 0.607 for the histological variables and RD. We found that RD significantly correlated with both optical density of myelinated fibers and fiber coherence, but FA correlated with neither histological finding. Factors other than degree of myelination and fiber coherence should be considered to fully account for regional variation in FA. PMID:24199809

Wei, Peter T; Leong, Dalun; Calabrese, Evan; White, Leonard; Pierce, Theodore; Platt, Simon; Provenzale, James

2013-10-01

205

Correlation analysis between eGFRcys and SXscore in patients with diabetes  

PubMed Central

The aim of the present study was to explore the association between the cystatin C-based estimated glomerular filtration rate (eGFRcys) and the SYNTAX score (SXscore) in patients with diabetes. To the best of our knowledge, this correlation has not been reported previously. The eGFRcys and SXscore from 612 consecutive patients with diabetes were retrospectively included in this study. The patients were angiographically diagnosed with coronary artery disease (CAD) between July 2010 and March 2012 at the Department of Endocrinology. The SXscore was calculated using a previously described SXscore algorithm. Pearson correlations were used to analyze the correlation between eGFRcys and SXscore. Patients with renal dysfunction were older, more often female and more likely to have a history of hypertension when compared with those with normal renal function. The eGFRcys values were significantly lower and the cystatin C levels were significantly higher in the highest SXscore group than those in other groups (P<0.001). Correlation analysis indicated that eGFRcys was negatively correlated with the SXscore (r=?0.7918, P<0.001). In addition, a significantly positive correlation was identified between levels of cystatin C and the SXscore (r=0.8891, P<0.001). In conclusion, eGFRcys is an independent predictor of SXscore in patients with diabetes. The eGFRcys-estimating method may be considered important in the assessment of the SXscore in patients with diabetes. PMID:24669241

YONG, ZHONG; ZHU, LIYONG; TAN, JUAN; ZHU, SHAIHONG

2014-01-01

206

Cosmic rays activity and monthly number of deaths: a correlative study.  

PubMed

We studied the relation between the intensity of cosmic rays, the level of solar/geomagnetic activity, and the monthly numbers of deaths in a large hospital in Israel and in all Lithuania. The Israeli data include 30526 hospital deaths, two groups of fatal suicides (2359, 2763), and 15435 suicidal attempts for two periods of 108 and 236 consecutive months. The national data for the entire Republic of Lithuania include 424925 deaths for the period of 120 consecutive months. Cosmic rays intensity was measured by an Apatity neutron monitor. We obtained the data on solar, geomagnetic radiovawe propagation, ionosphere ionization hours, proton flux of two energy levels (>90 and 60 MeV) from the National Geophysical Data Center at Goddard Space Flight Center, National Space Environment Center at Boulder, Colorado, USA, and from the Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN), Russia. We calculated Pearson coefficients and their probabilities for correlation between monthly space activity level and monthly number of male and female deaths from different causes. Cosmic rays activity revealed significant negative correlation with solar/geomagnetic activity indices and related physical phenomena levels. This activity strongly correlated with flux of protons with the energies >90 MeV proton flux and did not exhibit significant correlation with 60 MeV proton fluxes. Cosmic rays intensity correlation with monthly numbers of deaths was strong for noncardiovascular deaths, suicides, and traffic accidents. The correlation was much weaker for deaths caused by ishemic heart disease and strokes. PMID:12099402

Stoupel, E; Israelevich, P; Petrauskiene, J; Kalediene, R; Abramson, E; Gabbay, U; Sulkes, J

2002-01-01

207

High-resolution correlation  

NASA Astrophysics Data System (ADS)

In the basic correlation process a sequence of time-lag-indexed correlation coefficients are computed as the inner or dot product of segments of two signals. The time-lag(s) for which the magnitude of the correlation coefficient sequence is maximized is the estimated relative time delay of the two signals. For discrete sampled signals, the delay estimated in this manner is quantized with the same relative accuracy as the clock used in sampling the signals. In addition, the correlation coefficients are real if the input signals are real. There have been many methods proposed to estimate signal delay to more accuracy than the sample interval of the digitizer clock, with some success. These methods include interpolation of the correlation coefficients, estimation of the signal delay from the group delay function, and beam forming techniques, such as the MUSIC algorithm. For spectral estimation, techniques based on phase differentiation have been popular, but these techniques have apparently not been applied to the correlation problem . We propose a phase based delay estimation method (PBDEM) based on the phase of the correlation function that provides a significant improvement of the accuracy of time delay estimation. In the process, the standard correlation function is first calculated. A time lag error function is then calculated from the correlation phase and is used to interpolate the correlation function. The signal delay is shown to be accurately estimated as the zero crossing of the correlation phase near the index of the peak correlation magnitude. This process is nearly as fast as the conventional correlation function on which it is based. For real valued signals, a simple modification is provided, which results in the same correlation accuracy as is obtained for complex valued signals.

Nelson, D. J.

2007-09-01

208

Correlation between nitrogen fixation rate and alginate productivity of an indigenous Azotobacter vinelandii from Iran  

PubMed Central

Background and Objectives Azotobacter vinelandii, a gamma-proteobacterium, is an obligate aerobic free-living gram-negative soil bacterium capable of fixing nitrogen. Oxygen transfer rate into the cell is reduced by the increase of alginate concentrations during the course of A. vinelandii cultivation. This phenomenon provides a low intracellular oxygen concentration needed for nitrogenase activity. The aim of this study was to design a simple strategy to explain the alginate production, cell growth and nitrogenase activity correlation in A. vinelandii under aerobic conditions. Material and Methods Thirty-five different soil samples were taken from the rhizosphere of agricultural crops of Iran. Enrichment and isolation strategies were employed for microbial isolation. Physiological and biochemical characteristics were determined. Molecular identification was performed using selective nifH-g1 primers. Alginate production and nitrogenase activity assay by each isolate of Azotobacter were carried out. Bacterial growth, alginate production and Nitrogenase activity were conducted by time-coursed quantitative measurements. Results Total of 26 isolates were selected after enrichment, isolation, and screening. The isolate was identified by molecular tests as A. vinelandii. The highest alginate productions of 1.02 g/l and 0.91g/l were noted after 4 days in 8 isolates, cell biomass of which were estimated 4.88-5.26 g/l. Six of 8 isolates were able to fix atmospheric N2 on nitrogen-free medium. Rates obtained in isolates were in the range of 12.1 to 326.4 nmol C2H4 h-1 vial-1. Conclusions Nitrogen fixation and alginate production yielded significant and positive Pearson's correlation coefficient of R2 = 0.760, p ? 0.02. Finally association between bacterial growth, alginate production and nitrogenase activity almost noticeable yielded significant and positive Pearson's correlation coefficient R2= 0.723, p ? 0.04. PMID:23066492

Nosrati, R; Owlia, P; Saderi, H; Olamaee, M; Rasooli, I; Akhavian, Tehrani A

2012-01-01

209

FEBRUARY 2001 S&T TEST REPORT  

E-print Network

A STAR TOP ASTRO WEB SITES SHEDDING LIGHT ON DARK SKIES: · Build a "Dark Meter" · New Dark-Sky Rating NEW 102-MM TELESCOPE WATCH A PLANET BLOT OUT A STAR TOP ASTRO WEB SITES SHEDDING LIGHT ON DARK SKIES: · Build a "Dark Meter" · New Dark-Sky Rating Scale AURIGA'S SPARKLING STAR CLUSTERS NEW PUBLIC OBSERVATORY

Schrijver, Karel

210

The t-test Tutorial: Comparing Cultures  

NSDL National Science Digital Library

This tutorial, created by Dale Berger of Claremont Graduate University, takes the learner step-by-step in applying descriptive and inferential statistics using a real world situation. The site focuses on the cultural differences in child rearing in the countries of Belize and Samoa. Overall, this is a great site for applied statistical theories.

Berger, Dale

211

Correlation in photodetachment  

SciTech Connect

Electron correlation plays a major role in all aspects of the photodetachment of an electron from a negative ion. Photodetachment measurements are well suited to investigate the relatively short range forces associated with correlation due to the absence of the long range Coulomb interaction. Measurements of electron affinities, asymmetry parameters and cross sections are described to illustrate the influence of correlation on photodetachment. 25 refs., 4 figs.

Pegg, D.J. (Oak Ridge National Lab., TN (USA) Tennessee Univ., Knoxville, TN (USA). Dept. of Physics)

1991-01-01

212

Notes on correlation femtoscopy  

SciTech Connect

The particle correlations at small relative velocities are sensitive to the space-time characteristics of the production processes on a femtometer scale owing to the effects of quantum statistics and finalstate interaction. Though the final-state interaction complicates the correlation analysis, it is an important source of information allowing for coalescence femtoscopy, correlation femtoscopy with unlike particles including access to the relative space-time asymmetries in particle production, and a study of strong interactions between specific particles. I will briefly discuss the history and basics of correlation femtoscopy, some of the recent results from femtoscopy of relativistic heavy-ion collisions, and their consequences.

Lednicky, R., E-mail: lednicky@fzu.c [Joint Institute for Nuclear Research (Russian Federation)

2008-09-15

213

Correlation engine prototype  

NASA Astrophysics Data System (ADS)

The CERN monitoring prototype, part of the fabric management work package (WP4) of the DataGrid project, task Monitoring, collects monitoring data from farm nodes in CERN into a central monitoring database. Performing correlations on the data in the monitoring database should help to foresee exceptions on individual nodes or node groups and to analyze performance of the farm. The Correlation Engine Prototype has been developed to provide easy adding of new correlations of monitoring data and actions triggered in case of exceptions. The current prototype is written in Perl. The results of the correlation engine can be accessed through a web-interface.

Pose, V.; Panzer-Steindel, B.

2003-04-01

214

Correlation of the clinical and physical image quality in chest radiography for average adults with a computed radiography imaging system  

PubMed Central

Objective: The purpose of this study was to examine the correlation between the quality of visually graded patient (clinical) chest images and a quantitative assessment of chest phantom (physical) images acquired with a computed radiography (CR) imaging system. Methods: The results of a previously published study, in which four experienced image evaluators graded computer-simulated postero-anterior chest images using a visual grading analysis scoring (VGAS) scheme, were used for the clinical image quality measurement. Contrast-to-noise ratio (CNR) and effective dose efficiency (eDE) were used as physical image quality metrics measured in a uniform chest phantom. Although optimal values of these physical metrics for chest radiography were not derived in this work, their correlation with VGAS in images acquired without an antiscatter grid across the diagnostic range of X-ray tube voltages was determined using Pearson’s correlation coefficient. Results: Clinical and physical image quality metrics increased with decreasing tube voltage. Statistically significant correlations between VGAS and CNR (R=0.87, p<0.033) and eDE (R=0.77, p<0.008) were observed. Conclusion: Medical physics experts may use the physical image quality metrics described here in quality assurance programmes and optimisation studies with a degree of confidence that they reflect the clinical image quality in chest CR images acquired without an antiscatter grid. Advances in knowledge: A statistically significant correlation has been found between the clinical and physical image quality in CR chest imaging. The results support the value of using CNR and eDE in the evaluation of quality in clinical thorax radiography. PMID:23568362

Wood, T J; Beavis, A W; Saunderson, J R

2013-01-01

215

Correlation between ORange® (Gen 1, pseudophakic) intraoperative refraction and 1-week postcataract surgery autorefraction  

PubMed Central

Background: This study aimed to find the strength of the correlation between ORange® (intraoperative wavefront aberrometer) objective refraction during pseudophakic cataract surgery (Gen 1) and 1-week objective autorefraction postcataract surgery in order to establish the clinical degree of confidence in the ORange. Gen 1 was used because Gen 2 was not available at the time of the study. However, Gen 1 can still be a good reference. Methods: Thirty-two consecutive eyes were included in this prospective nonrandomized study. ORange was used after phacoemulsification and intraocular lens implantation. There were no complications and no withdrawals from the study. The refraction data from the ORange were recorded in spherical equivalents and put into Excel. One week postoperatively, autorefraction was done and the data were again recorded in spherical equivalents and put into Excel. Both sets of data were then transferred to SPSS for a correlation study. Because ORange is an objective refractor, it is necessary to use another objective refractor, such as the Zeiss Autorefractor, for comparison. Measurement at 1 week postoperatively is for cornea clearance for autorefraction and is the closest time to intraoperative assessment for comparison. Results: The Pearson correlation was r = +0.56, P < 0.01, which qualifies for a moderate or good correlation (0.5–0.75). Conclusion: Intraoperative refraction using the ORange Gen 1 after cataract surgery and intraocular lens implantation is moderate to good when correlated with objective autorefraction 1 week after cataract surgery. PMID:21383949

Chen, Ming

2011-01-01

216

Human gene correlation analysis (HGCA): A tool for the identification of transcriptionally co-expressed genes  

PubMed Central

Background Bioinformatics and high-throughput technologies such as microarray studies allow the measure of the expression levels of large numbers of genes simultaneously, thus helping us to understand the molecular mechanisms of various biological processes in a cell. Findings We calculate the Pearson Correlation Coefficient (r-value) between probe set signal values from Affymetrix Human Genome Microarray samples and cluster the human genes according to the r-value correlation matrix using the Neighbour Joining (NJ) clustering method. A hyper-geometric distribution is applied on the text annotations of the probe sets to quantify the term overrepresentations. The aim of the tool is the identification of closely correlated genes for a given gene of interest and/or the prediction of its biological function, which is based on the annotations of the respective gene cluster. Conclusion Human Gene Correlation Analysis (HGCA) is a tool to classify human genes according to their coexpression levels and to identify overrepresented annotation terms in correlated gene groups. It is available at: http://biobank-informatics.bioacademy.gr/coexpression/. PMID:22672625

2012-01-01

217

Ultrasound Thickness of Bladder Wall in Continent and Incontinent Women and Its Correlation with Cystometry  

PubMed Central

Objective. To compare bladder wall thickness in two kinds of urinary incontinent women—stress urinary incontinence (SUI) and overactive bladder (OAB) with urodynamic detrusor overactivity (DO), and to compare them with continent patients by ultrasound, also, correlate with cystometric results in incontinent women. Methods. 91 women were divided into the following groups: continent (n = 31), SUI (n = 30), and DO (n = 30) groups after clinical evaluation and urodynamic test (only in incontinent women). Transvaginal ultrasound was performed to the bladder wall thickness (BWT) measurement. The mean of BWT was calculated and data were analyzed with ANOVA and Turkey's multiple comparison tests. Pearson's correlation coefficient (r) was used to compare two variables. Receiver operating characteristic (ROC) curve was performed to study BWT as a diagnostic parameter. Results. BWT in DO group was significantly higher than that in the other groups (P < 0.005). A moderate positive correlation was found between BWT and maximum bladder pressure during involuntary bladder contraction. There was no difference in BWT between SUI and continent groups. DO group had lower first desire to void and cystometric capacity. Maximum bladder pressure at detrusor contraction had a moderate positive correlation with BWT. The ROC revealed an area under the curve of 0.962 (95%?CI, 0.90–1.01). Conclusions. DO patients have increased bladder wall thickness, lower first desire to void, and lower cystometric capacity. There was a moderate correlation between BWT and maximum bladder pressure during involuntary bladder contraction.

Otsuki, Edney Norio; Oliveira, Emerson; Sartori, Marair Gracio Ferreira; Girão, Manoel João Batista Castelo; Jármy-Di Bella, Zsuzsanna Ilona Katalin

2014-01-01

218

[Correlation between radiologic and ultrasonographic patterns and clinical manifestations in symptomatic hip osteoarthritis].  

PubMed

Increasing amounts of data have recently been published regarding ultrasonographic (US) findings of osteoarthritic joints, but very few data concern hip joints. In the current study we described US patterns concerning 490 patients affected by symptomatic hip osteoarthritis (OA) who underwent to intra-articular injections of hyaluronic products under US guidance. All patients were studied by US and X-ray of hip, clinical evaluation was assessed by the followings indexes: Lequesne, pain VAS, ICED, Global Physician Assessment and Global Patient Assessment. US findings were summarized in four main patterns, effusion and synovial proliferation were also detected. The aim of this study was to correlate US findings with clinical assessment and radiographic findings (according to Kellgren-Lawrence classification). Pearson's r correlation coefficient were computed and come out significant and positive between X ray and US patterns and between clinical indexes and US patterns. Also the correlation between K-L score and US patterns showed a significant positive correlation indicating that higher K-L scores are associated with increasing abnormal US findings. Our data suggest that ultrasonography of the hip may give useful information about the state of synovial membrane, synovial fluid, joint margins and bone profile in hip OA. Further studies are needed to evaluate their prevalence in hip OA symptomatic and not-symptomatic patients and their correlation to treatment outcome. PMID:17435843

Migliore, A; Tormenta, S; Iannessi, F; Mascheroni, E; Barbati, E; Capuano, A; Diaco, M; Massafra, U; Padalino, C; Vacca, F; Alimonti, A; Martin, L S; Granata, M

2007-01-01

219

Correlations between scores on the Wechsler Intelligence Scale for Children-III and the General Purpose Abbreviated Battery of the Stanford-Binet IV.  

PubMed

Estimations of some relationships among scores on the "General Purpose Abbreviated Battery" of the Stanford-Binet: Fourth Edition and the Wechsler Intelligence Scale for Children-III were based on the responses of 14 boys and 18 girls enrolled in Grades 3, 4, and 5 and who took both tests. Of 13 Pearson correlations between the Binet IV composite score and the Wechsler subtest scores and IQs 12 were statistically significant (rs = .45 to .74). The new Wechsler scale appears to be a valid instrument for the 32 children (8-8 to 11-11) who were tested. PMID:8337322

Carvajal, H H; Hayes, J E; Lackey, K L; Rathke, M L; Wiebe, D A; Weaver, K A

1993-06-01

220

Explorations in Statistics: Correlation  

ERIC Educational Resources Information Center

Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This sixth installment of "Explorations in Statistics" explores correlation, a familiar technique that estimates the magnitude of a straight-line relationship between two variables. Correlation is meaningful only when the…

Curran-Everett, Douglas

2010-01-01

221

Explorations in statistics: correlation  

NSDL National Science Digital Library

Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This sixth installment of Explorations in Statistics explores correlation, a familiar technique that estimates the magnitude of a straight-line relationship between two variables. Correlation is meaningful only when the two variables are true random variables: for example, if we restrict in some way the variability of one variable, then the magnitude of the correlation will decrease. Correlation cannot help us decide if changes in one variable result in changes in the second variable, if changes in the second variable result in changes in the first variable, or if changes in a third variable result in concurrent changes in the first two variables. Correlation can help provide us with evidence that study of the nature of the relationship between x and y may be warranted in an actual experiment in which one of them is controlled.

PhD Douglas Curran-Everett (National Jewish Medical and Research Center Div. Biostatistics, Depts. Prev. Med./Biometrics, Physiology/Biophys)

2010-10-01

222

Correlation among auto-refractor, wavefront aberration, and subjective manual refraction  

NASA Astrophysics Data System (ADS)

Three optometry methods which include auto-refractor, wavefront aberrometer and subjective manual refraction were studied and compared in measuring low order aberrations of 60 people"s 117 normal eyes. Paired t-test and linear regression were used to study these three methods" relationship when measuring myopia with astigmatism. In order to make the analysis more clear, we divided the 117 normal eyes into different groups according to their subjective manual refraction and redid the statistical analysis. Correlations among three methods show significant in sphere, cylinder and axis in all groups, with sphere"s correlation coefficients largest(R>0.98, P<0.01) and cylinder"s smallest (0.90t-test before grouping showed the difference of three optometry methods in measuring sphere was significant (P<0.01) while axis"s difference was not significant (P>0.01). Auto-refractor had significant change from the other two methods when measuring cylinder (P<0.01). The results after grouping differed a little from the analysis among total people. Although three methods showed significant change from each other in certain parameters, the amplitude of these differences were not large, which indicated that the coherence of auto-refractor, wavefront aberrometer and subjective refraction is good. However, we suggested that wavefront aberration measurement could be a good starting point of optometry, subjective refraction is still necessary for refinement.

Li, Qi; Ren, Qiushi

2005-01-01

223

Lower Urinary Tract Symptoms, Erectile Dysfunction, and Their Correlation in Men Aged 50 Years and Above: A Cross-Sectional Survey in Beijing, China  

PubMed Central

Background The aim of this study was to investigate the correlation between incidence of lower urinary tract symptoms and erectile dysfunction in men aged ?50 years. Material/Methods A cross-sectional study was performed in 1644 men aged >50 years in Beijing. The International Index of Erectile Function (IIEF)-5 and International Prostate Symptom Score were recorded for each patient. Pearson’s chi-square test and Spearman correlation coefficients were used to analyze the International Prostate Symptom Scores and lower urinary tract symptoms, and their correlations with erectile dysfunction. Results The incidence rates of erectile dysfunction among men with mild, moderate, and severe lower urinary tract symptoms were 85.7, 93.7, and 97.9%, respectively. Interestingly, the total IIEF-5 score significantly correlated with the total International Prostate Symptom Score (r=?0.335; P<0.01), obstructive symptoms (r=?0.276; P<0.01), and irritative symptoms (r=?0.326; P<0.01). The correlation between the severity of lower urinary tract symptoms and that of erectile dysfunction was consistently maintained (r=0.304; P<0.01). Age significantly correlated with International Prostate Symptom Score (r=0.388; P<0.01), lower urinary tract symptoms severity (r=0.457; P<0.01), total IIEF-5 score (r=?0.533; P<0.01), and erectile dysfunction severity (r=0.529; P<0.01). Conclusions The incidence of lower urinary tract symptoms and erectile dysfunction in aging men increase with age, and the severity of erectile dysfunction is positively correlated with the severity of lower urinary tract symptoms. PMID:25543209

Song, Jian; Shao, Qiang; Tian, Ye; Chen, Shan

2014-01-01

224

Correlation of free-response and receiver-operating-characteristic area-under-the-curve estimates: Results from independently conducted FROC/ROC studies in mammography  

PubMed Central

Purpose: From independently conducted free-response receiver operating characteristic (FROC) and receiver operating characteristic (ROC) experiments, to study fixed-reader associations between three estimators: the area under the alternative FROC (AFROC) curve computed from FROC data, the area under the ROC curve computed from FROC highest rating data, and the area under the ROC curve computed from confidence-of-disease ratings. Methods: Two hundred mammograms, 100 of which were abnormal, were processed by two image-processing algorithms and interpreted by four radiologists under the FROC paradigm. From the FROC data, inferred-ROC data were derived, using the highest rating assumption. Eighteen months afterwards, the images were interpreted by the same radiologists under the conventional ROC paradigm; conventional-ROC data (in contrast to inferred-ROC data) were obtained. FROC and ROC (inferred, conventional) data were analyzed using the nonparametric area-under-the-curve (AUC), (AFROC and ROC curve, respectively). Pearson correlation was used to quantify the degree of association between the modality-specific AUC indices and standard errors were computed using the bootstrap-after-bootstrap method. The magnitude of the correlations was assessed by comparison with computed Obuchowski-Rockette fixed reader correlations. Results: Average Pearson correlations (with 95% confidence intervals in square brackets) were: Corr(FROC, inferred ROC) = 0.76[0.64, 0.84] > Corr(inferred ROC, conventional ROC) = 0.40[0.18, 0.58] > Corr (FROC, conventional ROC) = 0.32[0.16, 0.46]. Conclusions: Correlation between FROC and inferred-ROC data AUC estimates was high. Correlation between inferred- and conventional-ROC AUC was similar to the correlation between two modalities for a single reader using one estimation method, suggesting that the highest rating assumption might be questionable. PMID:23039631

Zanca, Federica; Hillis, Stephen L.; Claus, Filip; Van Ongeval, Chantal; Celis, Valerie; Provoost, Veerle; Yoon, Hong-Jun; Bosmans, Hilde

2012-01-01

225

Ozone Correlative Measurements Workshop  

NASA Technical Reports Server (NTRS)

A study was conducted to determine the necessary parameters for the correlation of data on Earth ozone. Topics considered were: (1) measurement accuracy; (2) equipment considerations (SBUV); and (3) ground based measurements to support satellite data.

Hilsenrath, E. (editor)

1985-01-01

226

Almost quantum correlations  

E-print Network

There have been a number of attempts to derive the set of quantum non-local correlations from reasonable physical principles. Here we introduce $\\tilde{Q}$, a set of multipartite supra-quantum correlations that has appeared under different names in fields as diverse as graph theory, quantum gravity and quantum information science. We argue that $\\tilde{Q}$ may correspond to the set of correlations of a reasonable physical theory, in which case the research program to reconstruct quantum theory from device-independent principles is met with strong obstacles. In support of this conjecture, we prove that $\\tilde{Q}$ is closed under classical operations and satisfies the physical principles of Non-Trivial Communication Complexity, No Advantage for Nonlocal Computation, Macroscopic Locality and Local Orthogonality. We also review numerical evidence that almost quantum correlations satisfy Information Causality.

Miguel Navascués; Yelena Guryanova; Matty J. Hoban; Antonio Acín

2014-03-18

227

Extractable work from correlations  

E-print Network

Work and quantum correlations are two fundamental resources in thermodynamics and quantum information theory. In this work we study how to use correlations among quantum systems to optimally store work. We analyse this question for isolated quantum ensembles, where the work can be naturally divided into two contributions: a local contribution from each system, and a global contribution originating from correlations among systems. We focus on the latter and consider quantum systems which are locally thermal, thus from which any extractable work can only come from correlations. We compute the maximum extractable work for general entangled states, separable states, and states with fixed entropy. Our results show that while entanglement gives an advantage for small quantum ensembles, this gain vanishes for a large number of systems.

Martí Perarnau-Llobet; Karen V. Hovhannisyan; Marcus Huber; Paul Skrzypczyk; Nicolas Brunner; Antonio Acín

2014-07-29

228

Fluorescence Correlation Spectroscopy  

NSDL National Science Digital Library

This paper, which was previously published as part of an online biophysics textbook, provides detailed information about concepts related to fluorescence correlation spectroscopy. Sections of the document include writing on experimental realization, theoretical concepts, and applications of this technology.

Haustein, Elke

229

Co-occurrence correlations of heavy metals in sediments revealed using network analysis.  

PubMed

In this study, the correlation-based study was used to identify the co-occurrence correlations among metals in marine sediment of Hong Kong, based on the long-term (from 1991 to 2011) temporal and spatial monitoring data. 14 stations out of the total 45 marine sediment monitoring stations were selected from three representative areas, including Deep Bay, Victoria Harbour and Mirs Bay. Firstly, Spearman's rank correlation-based network analysis was conducted as the first step to identify the co-occurrence correlations of metals from raw metadata, and then for further analysis using the normalized metadata. The correlations patterns obtained by network were consistent with those obtained by the other statistic normalization methods, including annual ratios, R-squared coefficient and Pearson correlation coefficient. Both Deep Bay and Victoria Harbour have been polluted by heavy metals, especially for Pb and Cu, which showed strong co-occurrence with other heavy metals (e.g. Cr, Ni, Zn and etc.) and little correlations with the reference parameters (Fe or Al). For Mirs Bay, which has better marine sediment quality compared with Deep Bay and Victoria Harbour, the co-occurrence patterns revealed by network analysis indicated that the metals in sediment dominantly followed the natural geography process. Besides the wide applications in biology, sociology and informatics, it is the first time to apply network analysis in the researches of environment pollutions. This study demonstrated its powerful application for revealing the co-occurrence correlations among heavy metals in marine sediments, which could be further applied for other pollutants in various environment systems. PMID:24559934

Liu, Lili; Wang, Zhiping; Ju, Feng; Zhang, Tong

2015-01-01

230

Neural Correlates of Sympathy  

E-print Network

CORRELATES OF SYMPATHY iii ABSTRACT Neural Correlates of Sympathy. (April 2009) Laura Christine Gravens Department of Psychology Texas A&M University Research Advisor: Dr. Eddie Harmon-Jones Department of Psychology Sympathy has not been.... 20 CONTACT INFORMATION Name: Laura Christine Gravens Professional Address: c/o Dr. Eddie Harmon Jones Department of Psychology Texas A&M University College Station, TX 77843-4235 Email Address: lauragravens@gmail.com Education: B...

Gravens, Laura

2011-01-11

231

CARMA Correlator Graphical Setup  

NASA Astrophysics Data System (ADS)

CARMA Correlator Graphical Setup (CGS) is a Java tool to help users of the Combined Array for Research in Millimeter-wave Astronomy (CARMA) plan observations. It allows users to visualize the correlator bands overlaid on frequency space and view spectral lines within each band. Bands can be click-dragged to anywhere in frequency and can have their properties (e.g., bandwidth, quantization level, rest frequency) changed interactively. Spectral lines can be filtered from the view by expected line strength to reduce visual clutter. Once the user is happy with the setup, a button click generates the Python commands needed to configure the correlator within the observing script. CGS can also read Python configurations from an observing script and reproduce the correlator setup that was used. Because the correlator hardware description is defined in an XML file, the tool can be rapidly reconfigured for changing hardware. This has been quite useful as CARMA has recently commissioned a new correlator. The tool was written in Java by high school summer interns working in UMD's Laboratory for Millimeter Astronomy and has become an essential planning tool for CARMA PIs.

Wu, D.; Shaya, B.; Pound, M. W.

2011-07-01

232

Robust correlation analyses: false positive and power validation using a new open source matlab toolbox.  

PubMed

Pearson's correlation measures the strength of the association between two variables. The technique is, however, restricted to linear associations and is overly sensitive to outliers. Indeed, a single outlier can result in a highly inaccurate summary of the data. Yet, it remains the most commonly used measure of association in psychology research. Here we describe a free Matlab((R)) based toolbox (http://sourceforge.net/projects/robustcorrtool/) that computes robust measures of association between two or more random variables: the percentage-bend correlation and skipped-correlations. After illustrating how to use the toolbox, we show that robust methods, where outliers are down weighted or removed and accounted for in significance testing, provide better estimates of the true association with accurate false positive control and without loss of power. The different correlation methods were tested with normal data and normal data contaminated with marginal or bivariate outliers. We report estimates of effect size, false positive rate and power, and advise on which technique to use depending on the data at hand. PMID:23335907

Pernet, Cyril R; Wilcox, Rand; Rousselet, Guillaume A

2012-01-01

233

Stature and gender determination and their correlation using odontometry and skull anthropometry  

PubMed Central

Background: When the body has been mutilated, it is common to have the extremities or head amputated from the trunk. In concern with forensic odontology, an estimate must have been made based on the correlation of osteometry along with odontometry in determining sex, race and stature. Objective: The objective of this study is to investigate and correlate height and gender from odontometry and anthropometric data of the skull. Materials and Methods: The study was conducted in the Department of Oral and Maxillofacial Pathology and Microbiology, I.T.S Center for Dental studies and Research, Muradnagar, Ghaziabad (UP) with the representative study subjects of 60 patients as 30 males and 30 females in the age group of 15-25 years. The selected parameters were measured and then correlated to investigate stature and gender from odontometry and anthropometric data of the skull. Results: On linear regression analysis, the selected parameters were found to be statistically significant predictor of height. It was also established by Karl Pearson's coefficient correlation that the left mandibular canine index for female was statistically significant to show sexual dimorphism. Conclusion: In the emerging field of forensic odontology, skull anthropometry, odontometry exhibits stature determination and strong sexual dimorphism. PMID:25125917

Gupta, Amit; Kumar, Kiran; Shetty, Devi Charan; Wadhwan, Vijay; Jain, Anshi; Khanna, Kaveri Surya

2014-01-01

234

Influence of Craniofacial Morphology on Hyoid Movement: A Preliminary Correlational Study  

PubMed Central

There has been little attention given to the relationship between variations in normal craniofacial morphology and swallowing physiology. This preliminary investigation evaluated the relationship between the Frankfort Mandibular Plane Angle (FMA) and hyoid displacement during swallowing. Hyoid movement was evaluated during 12-ml and 24-ml swallows of liquid barium in 12 healthy subjects (aged 20 to 29 years, median 23 years). Lateral projection videoflurography was utilized. Positions of the hyoid at maximum forward displacement, maximum upward displacement, start position, and ending position were determined using image analysis software. The mean FMA was 28.92° ± 4.08 o (mean ± SD, range 20 to 34). A Pearson Correlation (? 0.05) demonstrated that hyoid forward displacement was significantly inversely correlated with the FMA (R=?.68, P=0.015 (12-ml) and R=?.72, P=0.009 (24-ml); thus the greater the FMA, the smaller was the hyoid forward displacement. Upward displacement of the hyoid was not significantly correlated with FMA for 12-ml (R= ?0.41, P=0.55) or 24-ml swallows (R=0.21, P=0.512). Additionally, there was no significant correlation between hyoid starting or ending positions. In conclusion, the results of this preliminary study suggest that normal variations in morphology, as measured by the FMA, may influence hyoid movement and therefore affect the swallowing physiology. PMID:18716836

Dubner, Ronald; Mays, Keith A.

2009-01-01

235

Prevalence and Correlates of Depressive Symptoms and Resiliency among African American Women in a Community-Based Primary Health Care Center  

PubMed Central

The purpose of this cross-sectional pilot study was to determine the prevalence and correlates of depressive symptoms and resiliency among 290 African American women (AAW) in a community-based primary health care center. Descriptive statistics, Pearson product-moment correlation, and logistic regression analyses were conducted. Findings indicate that depressive symptoms are experienced by 49% of the participants, while 10% indicated a history of suicidal ideation. Participants had moderately high resiliency scores that had a statistically significant inverse relationship with depressive symptoms. This suggests that resiliency is potentially a protective factor for depressive symptoms. Depressive symptoms were positively correlated with participants’ diagnosis of at least one chronic disease. The strongest predictors of depressive symptoms were previous diagnoses of a mental health condition and unemployment. This study identifies risk and potential protective factors for depression among a clinic sample of AAW. PMID:24241263

Holden, Kisha B.; Bradford, L. Dianne; Hall, Stephanie P.; Belton, Allyson S.

2014-01-01

236

Strongly correlated materials.  

PubMed

Strongly correlated materials are profoundly affected by the repulsive electron-electron interaction. This stands in contrast to many commonly used materials such as silicon and aluminum, whose properties are comparatively unaffected by the Coulomb repulsion. Correlated materials often have remarkable properties and transitions between distinct, competing phases with dramatically different electronic and magnetic orders. These rich phenomena are fascinating from the basic science perspective and offer possibilities for technological applications. This article looks at these materials through the lens of research performed at Rice University. Topics examined include: Quantum phase transitions and quantum criticality in "heavy fermion" materials and the iron pnictide high temperature superconductors; computational ab initio methods to examine strongly correlated materials and their interface with analytical theory techniques; layered dichalcogenides as example correlated materials with rich phases (charge density waves, superconductivity, hard ferromagnetism) that may be tuned by composition, pressure, and magnetic field; and nanostructure methods applied to the correlated oxides VO? and Fe?O?, where metal-insulator transitions can be manipulated by doping at the nanoscale or driving the system out of equilibrium. We conclude with a discussion of the exciting prospects for this class of materials. PMID:22893361

Morosan, Emilia; Natelson, Douglas; Nevidomskyy, Andriy H; Si, Qimiao

2012-09-18

237

Correlation between Chronological Age, Dental Age and Skeletal Age among Monozygoyic and Dizygotic Twins  

PubMed Central

Introduction: Chronological age, dental development, height and weight measurements, sexual maturation characteristics and skeletal age are some biological indicators that have been used to identify time of growth. Many researchers have agreed that skeletal maturity is closely related to the craniofacial growth, and bones of hand and wrist are reliable parameters in assessing it. The complete hand and wrist radiograph involves 30 bones and assessment of these bones is one elaborate task. The present study is therefore, undertaken to assess the correlation between the chronological age, dental age and skeletal ages among different types of twins. Materials and Methods: The study consisted of 60 subjects (30 twins) aged 8 to 16 years, divided into group of 10 monozygotic, 10 dizygotic and 10 mixed sex twins. The sample was selected from Twin Survey- 2008 conducted by Department of Orthodontics and Dentofacial Orthopaedics, Sree Balaji Dental College and Hospital, Chennai. Their zygosity was determined by sex, blood groups and by the parent. The chronological age was measured by the date of birth given by the parents. Panoramic and hand wrist x-rays were taken. Dental age was assessed by Demerjian et al method and skeletal age by Greulich and Pyle method. The correlation among twins in dental and skeletal ages with the chronological age was assessed using Correlation Coefficient and Student's't' Test. Results: The obtained data was fed into the computer and statistical analysis was done for the same using the SPSS version 10.0. Statistical significance was tested at P<0.05 level. Mean and Standard Deviation, Correlation Coefficient, Student's't' Test statistical methods were employed. The result showed highly significant 'p' value as <0.001 in all the correlations except for mixed pairs. Descriptive statistics in most of the areas demonstrated a non-significant result between zygosity groups. Conclusion: There is a correlation existing between the individual’s chronological age, dental age and skeletal age and correlation also exists in the twin pairs of the same zygosity and among each pair but no correlation exists between different zygotic twins. How to cite this article: Gupta M, Divyashree R, Abhilash P R, Bijle M N A, Murali K V. Correlation between Chronological Age, Dental Age and Skeletal Age among Monozygoyic and Dizygotic Twins. J Int Oral Health 2013; 3(1):16-22. PMID:24155573

Gupta, Mohit; Divyashree, R; Abhilash, PR; A Bijle, Mohammed Nadeem; Murali, KV

2013-01-01

238

Nonlocality of quantum correlations  

E-print Network

We show that only those composite quantum systems possessing nonvanishing quantum correlations have the property that any nontrivial local unitary evolution changes their global state. This type of nonlocality occurs also for states that do not violate a Bell inequality, such as, for instance, Werner states with a low degree of entanglement. We derive the exact relation between the global state change induced by local unitary evolutions and the amount of quantum correlations. We prove that the minimal change coincides with the geometric measure of discord, thus providing the latter with an operational interpretation in terms of the capability of a local unitary dynamics to modify a global state. We establish rigorously that Werner states are the maximally quantum correlated two-qubit states, and thus are the ones that maximize this novel type of nonlocality.

Streltsov, A; Roga, W; Bruß, D; Illuminati, F

2012-01-01

239

Correlation-Peak Imaging  

NASA Astrophysics Data System (ADS)

Identification and quantitation in conventional 1H spectroscopic imaging in vivois often hampered by the small chemical-shift range. To improve the spectral resolution of spectroscopic imaging, homonuclear two-dimensional correlation spectroscopy has been combined with phase encoding of the spatial dimensions. From the theoretical description of the coherence-transfer signal in the Fourier-transform domain, a comprehensive acquisition and processing strategy is presented that includes optimization of the width and the position of the acquisition windows, matched filtering of the signal envelope, and graphical presentation of the cross peak of interest. The procedure has been applied to image the spatial distribution of the correlation peaks from specific spin systems in the hypocotyl of castor bean ( Ricinus communis) seedlings. Despite the overlap of many resonances, correlation-peak imaging made it possible to observe a number of proton resonances, such as those of sucrose, ?-glucose, glutamine/glutamate, lysine, and arginine.

Ziegler, A.; Metzler, A.; Köckenberger, W.; Izquierdo, M.; Komor, E.; Haase, A.; Décorps, M.; von Kienlin, M.

240

Scatter Plots and Correlation  

NSDL National Science Digital Library

This webpage will be helpful for students learning to analyze data and create scatter plots. Specifically, these examples demonstrate how to determine correlations, or relationships, between sets of data. The slope of the line created by the data will show if there is a positive, negative, or no correlation between the sets of data. At the bottom of the page, a link is included for students who would like to learn how to create scatter plots with a graphing calculator. These examples are explained clearly and include useful graphics.

2012-08-14

241

Correlation ion mobility spectroscopy  

DOEpatents

Correlation ion mobility spectrometry (CIMS) uses gating modulation and correlation signal processing to improve IMS instrument performance. Closely spaced ion peaks can be resolved by adding discriminating codes to the gate and matched filtering for the received ion current signal, thereby improving sensitivity and resolution of an ion mobility spectrometer. CIMS can be used to improve the signal-to-noise ratio even for transient chemical samples. CIMS is especially advantageous for small geometry IMS drift tubes that can otherwise have poor resolution due to their small size.

Pfeifer, Kent B. (Los Lunas, NM); Rohde, Steven B. (Corrales, NM)

2008-08-26

242

Correlation between BPI Gene Upstream CpG Island Methylation and mRNA Expression in Piglets  

PubMed Central

Diarrhea and edematous disease are two major causes of mortality in postweaning piglets, and these conditions lead to huge economic losses in the swine industry. E. coli F18 is the primary causative agent of these two diseases. Bactericidal/permeability-increasing protein (BPI) plays an important role in the natural defense of the host. The aim of this study was to determine the correlation between BPI gene upstream CpG island methylation and mRNA expression. In this study, bisulfite sequencing PCR (BSP) was used to detect the methylation status of the BPI gene upstream CpG island and fluorescence quantitative PCR was used to detect BPI expression in the duodenum of piglets from birth to weaning age. BPI upstream CpG islands were shown to have many putative transcription factor binding sites, 10 CpG sites and every CpG site was methylated. The CpG island methylation level was lowest in 30-day piglets and was significantly lower than levels in 8-day piglets (p < 0.05). BPI mRNA expression was significantly higher in 30-day piglets than at any other age (p < 0.05). Pearson’s correlation analysis showed that the methylation status of the CpG island was negatively correlated with BPI mRNA expression. Statistical significances were found in CpG_1, CpG_3, CpG_4, CpG_7 and CpG_10 (p < 0.05). The data indicate that BPI expression is improved by demethylation of the BPI gene upstream CpG island. Furthermore, CpG_1, CpG_3, CpG_4, CpG_7 and CpG_10 may be critical sites in the regulation of BPI gene expression. PMID:24945309

Wang, Jing; Yin, Xuemei; Sun, Li; Sun, Shouyong; Zi, Chen; Zhu, Guoqiang; Wu, Shenglong; Bao, Wenbin

2014-01-01

243

Correlation Guessing Game  

NSDL National Science Digital Library

In this game activity, students match correlation values with plots generated by the applet. Competition in this game setting encourages students to become more involved in the classroom and attainment of learning objectives. This game is best if used in a lab setting, although it may be modified to fit other classroom situations.

Arroway, Pam; Gratton, Jennifer; Stanislav, Steve; Woodard, Roger

2009-02-20

244

Graphic Correlation Exercise  

NSDL National Science Digital Library

This is a graphic correlation lab exercise. It uses real data from a peer-reviewed journal publication by Lucy Edwards (1989). (I have manipulated the data set a little bit.) Students can finish the activity in two hours or less.

Dan Stephen

245

Neuroanatomical Correlates of Intelligence  

ERIC Educational Resources Information Center

With the advancement of image acquisition and analysis methods in recent decades, unique opportunities have emerged to study the neuroanatomical correlates of intelligence. Traditional approaches examining global measures have been complemented by insights from more regional analyses based on pre-defined areas. Newer state-of-the-art approaches…

Luders, Eileen; Narr, Katherine L.; Thompson, Paul M.; Toga, Arthur W.

2009-01-01

246

Correlating Aluminum Burning Times  

Microsoft Academic Search

Characteristics of aluminum combustion are summarized in an overview of the subject, focusing on the burning time of individual particles. Combustion data from over ten different sources with almost 400 datum points have been cataloged and correlated. Available models have also been used to evaluate combustion trends with key environmental parameters. The fundamental concepts that control aluminum combustion are discussed,

M. W. Beckstead

2005-01-01

247

Isaac Gary Correlator and  

E-print Network

-line Calibration Data Storage LAN Internet Burst monitor(s) RFI monitor(s) RF Converter Room IF Processor Room-end Element Computing System From other antennas #12;#12;Isaac Gary #12;#12; #12;#12;#12;Correlator and DSP 12) RFI monitor(s) RF Converter Room IF Processor Room Control Room RF-IF converter Back-end LO

248

Correlates of Adolescent Parenting.  

ERIC Educational Resources Information Center

Studied correlates of teenage parenting in self-selected sample of 177 teenage parents. Parental race, punitive attitudes toward child rearing, and parental age were statistically significant predictors of total Home Observation for Measurement of the Environment scores. Older, white adolescent mothers with less punitive attitudes toward child…

Reis, Janet S.; Herz, Elicia J.

1987-01-01

249

DISCUSS: Regression and Correlation  

NSDL National Science Digital Library

This module introduces correlation and regression through topics like scatterplots, lines, slopes, intercepts, applications of regression analysis, the line of best fit, goodness of fit, assumptions and how to check them, prediction, interpolation, extrapolation, and reliability. Excel spreadsheets are used to provide examples and exercises.

Hunt, Neville; Nicholson, James; Tyrrell, Sidney

2009-04-24

250

Correlations among GPA and scores on the Spanish version of WISC-R and the Woodcock-Johnson Achievement subtests for 10- to 12-year-old Puerto Rican children.  

PubMed

The purpose of this study was to explore the correlations among GPA, the Spanish version of the WISC-R, and the Woodcock Johnson Achievement subtests for a group of Puerto Rican children. The tests were administered to a sample of 32 children between the ages of 10 to 12 yr. in Grade 4. Pearson correlations between the Verbal, Performance, and Full Scale scaled scores in the WISC-R (Spanish Edition) ranged between .37 to .83. Correlations between subtests of the Woodcock-Johnson Achievement Test ranged from .26 to .70. The moderate correlation between the Total scaled scores on the Woodcock-Johnson and the scaled scores of the Performance, Verbal, and Full Scales of the Spanish WISC-R is indicative of the value of these Spanish-language instruments in diagnosing the intellectual and academic performance of Spanish-speaking populations in the United States. PMID:2349349

Rodriguez, V L; Prewitt Diaz, J O

1990-04-01

251

Isoflavones profiling of soybean [Glycine max (L.) Merrill] germplasms and their correlations with metabolic pathways.  

PubMed

The isoflavone diversity (44 varieties) of the soybean, Glycine max (L.) Merrill, from China, Japan, and Korea was examined by high-performance liquid chromatography. The profiles of 12 isoflavones identified from the grains were subjected to data-mining processes, including partial least-squares discriminant analysis (PLS-DA), Pearson's correlation analysis, and hierarchical clustering analysis (HCA). Although PLS-DA did not reveal significant differences among extracts of soybean from 3 countries, the results clearly show that the variation between varieties was low. The CS02554 variety was separate from the others in the first 2 principal components of PLS-DA. HCA of these phytochemicals resulted in clusters derived from closely related biochemical pathways. Daidzin, genistin, and glycitin contents were significantly correlated with their respective malonyl glycoside contents. Daidzein content correlated positively with genistein content (r=0.8189, P<0.0001). The CS02554 variety appears to be a good candidate for future breeding programs, as it contains high levels of isoflavone compounds. These results demonstrate the use of metabolite profiling combined with chemometrics as a tool for assessing the quality of food and identifying metabolic links in biological systems. PMID:24491728

Kim, Jae Kwang; Kim, Eun-Hye; Park, Inmyoung; Yu, Bo-Ra; Lim, Jung Dae; Lee, Young-Sang; Lee, Joo-Hyun; Kim, Seung-Hyun; Chung, Ill-Min

2014-06-15

252

``A Desideratum in Spectrology'': an Editor's Lament in the Great Correlation Era  

NASA Astrophysics Data System (ADS)

Of all the known observable characteristics of the stars in the late 19th Century, classification by the appearance of their spectra was by far the most problematic. In 1904, Edwin Frost lamented that some 23 distinct classification systems had been created, yet none were universally accepted. In 1908, the applied mathematician Karl Pearson and a student evaluated correlations between spectra and other characteristics of the stars, hoping to ``look upon the stellar universe as an orderly whole ... by which we pass from chaos to an organised and locally differentiated cosmos.'' None of the major spectral systems, however, allowed them to draw any conclusions, other than state a high correlation with color. Yet, by 1917, astronomers were making correlations, and applying them, to make some pretty strong statements about the nature and history of the sidereal system as well as the lives of the stars. One of the strongest was the technique of spectroscopic parallaxes. But even its discoverer, Walter Sydney Adams, worried about what it all meant. Writing to Eddington in 1917, Adams wished that ``we had more physical knowledge regarding the interpretations of stellar spectra.'' And as E. A. Milne observed some years later, in retrospect, ``[t]here was a gap in the logical argument.'' My talk will address some historiographical issues arising from this phase in the development of modern astrophysics that hopefully will illuminate why the gap was closed in the way it was closed, and the effect it had on the continuing process of spectral classification.

DeVorkin, David

2012-09-01

253

Growth Patterns of Subway/Metro Systems Tracked by Degree Correlation  

E-print Network

Urban transportation systems grow over time as city populations grow and move and their transportation needs evolve. Typical network growth models, such as preferential attachment, grow the network node by node whereas rail and metro systems grow by adding entire lines with all their nodes. The objective of this paper is to see if any canonical regular network forms such as stars or grids capture the growth patterns of urban metro systems for which we have historical data in terms of old maps. Data from these maps reveal that the systems' Pearson degree correlation grows increasingly from initially negative values toward positive values over time and in some cases becomes decidedly positive. We have derived closed form expressions for degree correlation and clustering coefficient for a variety of canonical forms that might be similar to metro systems. Of all those examined, only a few types patterned after a wide area network (WAN) with a "core-periphery" structure show similar positive-trending degree correl...

Whitney, Daniel E

2012-01-01

254

Possible correlation of selenoprotein W with inflammation factors in chicken skeletal muscles.  

PubMed

The aim of the present study was to investigate the possible correlation of selenoprotein W (SelW) with inflammatory injury induced by dietary selenium (Se) deficiency in chicken. One-day-old male chickens were fed either a commercial diet or a Se-deficient diet for 55 days. Then, the expression levels of SelW messenger RNA (mRNA) and inflammation-related genes (NF-?B, TNF-?, iNOS, COX-2, and PTGES) in chicken skeletal muscles (wing muscle, pectoral muscle, and thigh muscle) were determined at 15, 25, 35, 45, and 55 days old, respectively. In addition, the correlation between SelW mRNA expression and inflammation-related genes were assessed. The results showed that dietary Se deficiency reduced the mRNA expression of SelW in chicken wing, pectorals, and thigh muscles. In contrast, Se deficiency increased the mRNA expression levels of inflammation-related genes in chicken skeletal muscle tissues at different time points. The Pearson's correlation coefficients showed that the mRNA expression levels of inflammation-related genes were significantly negative related to SelW (p?

Wu, Qiong; Yao, Hai-Dong; Tan, Si-Ran; Zhang, Zi-Wei; Zhu, Yao-Hong; Xu, Shiwen

2014-11-01

255

A correlation between hard gamma-ray sources and cosmic voids along the line of sight  

NASA Astrophysics Data System (ADS)

We estimate the galaxy density along lines of sight to hard extragalactic gamma-ray sources by correlating source positions on the sky with a void catalogue based on the Sloan Digital Sky Survey (SDSS). Extragalactic gamma-ray sources that are detected at very high energy (VHE; E > 100 GeV) or have been highlighted as VHE-emitting candidates in the Fermi Large Area Telescope hard source catalogue (together referred to as `VHE-like' sources) are distributed along underdense lines of sight at the 2.4? level. There is also a less suggestive correlation for the Fermi hard source population (1.7?). A correlation between 10 and 500 GeV flux and underdense fraction along the line of sight for VHE-like and Fermi hard sources is found at 2.4? and 2.6?, calculated from the Pearson correlation coefficients of r = 0.57 and 0.47, respectively. The preference for underdense sight lines is not displayed by gamma-ray emitting galaxies within the second Fermi catalogue, containing sources detected above 100 MeV, or the SDSS Data Release 7 quasar catalogue. We investigate whether this marginal correlation might be a result of lower extragalactic background light (EBL) photon density within the underdense regions and find that, even in the most extreme case of a entirely underdense sight line, the EBL photon density is only 2 per cent less than the nominal EBL density. Translating this into gamma-ray attenuation along the line of sight for a highly attenuated source with opacity ?(E, z) ˜ 5, we estimate that the attenuation of gamma-rays decreases no more than 10 per cent. This decrease, although non-negligible, is unable to account for the apparent hard source correlation with underdense lines of sight.

Furniss, A.; Sutter, P. M.; Primack, J. R.; Domínguez, A.

2015-01-01

256

Bootstrapped Deattenuated Correlation: Nonnormal Distributions  

ERIC Educational Resources Information Center

Correlation attenuation due to measurement error and a corresponding correction, the deattenuated correlation, have been known for over a century. Nevertheless, the deattenuated correlation remains underutilized. A few studies in recent years have investigated factors affecting the deattenuated correlation, and a couple of them provide alternative…

Padilla, Miguel A.; Veprinsky, Anna

2014-01-01

257

FINCH: Fresnel Incoherent Correlation Hologram  

E-print Network

6 FINCH: Fresnel Incoherent Correlation Hologram Joseph Rosen1, Barak Katz1 and Gary Brooker2 1Ben hologram is dubbed Fresnel incoherent correlation hologram (FINCH) (Rosen & Brooker, 2007a). The FINCH, in the FINCH the object is correlated with quadratic phase functions, but the correlation is carried out

Rosen, Joseph

258

SPEARMEN-a dBase program for computation and testing of Spearman rank correlation coefficient distributions  

NASA Astrophysics Data System (ADS)

Large "hierarchical" datasets, that is a dataset that consists of identifiable subsamples of a population, offer the possibility to calculate a statistic per subsample. Together they form a sample distribution of that statistic. This distribution may be compared to some null hypothesis distribution and tested for deviations. To determine whether two variables are related, some type of correlation statistic usually is calculated. If the assumption for a normal distribution is not true necessarily the nonparametric Spearman rank correlation coefficient is better suited to estimate the existence of a relation than the Pearson product-moment correlation coefficient. The Spearman rank correlation coefficient thus has more general applicability at the cost of only a marginal loss in efficiency in the situation of normality. The dBase program SPEARMEN calculates Spearman rank correlation coefficients for all the subsamples of a "hierarchical" dataset and tests the sample distribution of this statistic against the null hypothesis Ho: rs = 0 by using the Kolmogorov-Smirnov one sample test. This approach has the advantage that it is sensitive to deviations for the entire range of observations and not only at critical tail-end values. For subsample sizes under 14 the theoretical null hypothesis permutation distribution is used, whereas above this value the distribution is approximated by a Student- t distribution. The program uns under dBaseIII +, dBaseIV, Foxbase +, and Clipper and can be used for virtually unlimited datasets.

Frapporti, G.; Linnartz, L. A. M.; Vriend, S. P.

259

Extracting Decision Correlation Rules  

NASA Astrophysics Data System (ADS)

In this paper, two concepts are introduced: decision correlation rules and contingency vectors. The first concept results from a cross fertilization between correlation and decision rules. It enables relevant links to be highlighted between sets of patterns of a binary relation and the values of target items belonging to the same relation on the twofold basis of the Chi-Squared measure and of the support of the extracted patterns. Due to the very nature of the problem, levelwise algorithms only allow extraction of results with long execution times and huge memory occupation. To offset these two problems, we propose an algorithm based both on the lectic order and contingency vectors, an alternate representation of contingency tables.

Casali, Alain; Ernst, Christian

260

Correlators in nontrivial backgrounds  

SciTech Connect

Operators in N=4 super Yang-Mills theory with an R-charge of O(N{sup 2}) are dual to backgrounds which are asymtotically AdS{sub 5}xS{sup 5}. In this article we develop efficient techniques that allow the computation of correlation functions in these backgrounds. We find that (i) contractions between fields in the string words and fields in the operator creating the background are the field theory accounting of the new geometry, (ii) correlation functions of probes in these backgrounds are given by the free field theory contractions but with rescaled propagators and (iii) in these backgrounds there are no open string excitations with their special end point interactions; we have only closed string excitations.

Mello Koch, Robert de [National Institute for Theoretical Physics, Department of Physics and Centre for Theoretical Physics, University of the Witwatersrand, Wits, 2050 (South Africa); Stellenbosch Institute for Advanced Studies, Stellenbosch (South Africa); Ives, Norman; Stephanou, Michael [National Institute for Theoretical Physics, Department of Physics and Centre for Theoretical Physics, University of the Witwatersrand, Wits, 2050 (South Africa)

2009-01-15

261

Selective correlations; not voodoo.  

PubMed

The problem of "voodoo" correlations-exceptionally high observed correlations in selected regions of the brain-is well recognized in neuroimaging. It arises when quantities of interest are estimated from the same data that was used to select them as interesting. In statistical terminology, the problem of inference following selection from the same data is that of selective inference. Motivated by the unwelcome side-effects of splitting the data- the recommended remedy-we adapt the recent developments in selective inference in order to construct confidence intervals (CIs) with good reproducibility prospects, even if selection and estimation are done with the same data. These intervals control the expected proportion of non-covered correlations in the selected voxels-the False Coverage Rate (FCR). They extend further toward zero than standard intervals, thus attenuating the impression made by highly biased observed correlations. They do so adaptively, in that they coincide with the standard CIs when far away from the selection point. We complement existing analytic proofs with a simulation, showing that the proposed intervals control the FCR in realistic social neuroscience problems. We also suggest a "confidence calibration plot", to allow the intervals to be reported in a clear and interpretable way. Applying the proposed methodology on a loss-aversion study, we demonstrate that with the sample size and selection type employed, selection bias is considerable. Finally, selective intervals are compared to the currently recommended data-splitting approach. We discover that our approach has more power and typically more informative, as no data is discarded. Computation of the intervals is implemented in an accompanying software package. PMID:25153699

Rosenblatt, J D; Benjamini, Y

2014-12-01

262

Relative Age Correlation  

NSDL National Science Digital Library

The purpose of this exercise is to introduce students to how simple relative age correlation principles can be used to reliable determine the relative ages of rock units and other geologic features. Students will apply the principles of original horizontality, superposition, cross-cutting relationships and inclusion to determine the relative ages of sedimentary rocks, igneous rocks and metamorphic rocks, as well as unconformities and faults.

Daley, Gwen

263

Time Integrating Digital Correlator  

NASA Astrophysics Data System (ADS)

This paper introduces "Interlaced Counter Propagating (ICP) Systolic Array", a new architecture for high speed systolic digital correlator operation. The interlaced arrangement of Multiply/Accumulate Units (MAUs) allow the processor to achieve 100% efficiency in MAU usage without need for complicated clocking scheme. It also shows a pipelined multiply and accumulate hardware combined with ICP architecture which allows the throughput to exceed the one with an array of conventional MAUs.

Tamura, Poohsan N.; Haugen, Paul R.; Betz, B. K.

1983-11-01

264

Correcting correlation function measurements  

NASA Astrophysics Data System (ADS)

Correlation functions measured as a function of ?? ,?? have emerged as a powerful tool to study the dynamics of particle production in nuclear collisions at high energy. They are however subject, like any other observables, to instrumental effects which must be properly accounted for to extract meaningful physics results. We compare the merits of several techniques used towards measurement of these correlation functions in nuclear collisions. We discuss and distinguish the effects of finite acceptance, and detection efficiency that may vary with collision parameters such as the position of the event in the detector and the instantaneous luminosity of the beam. We focus in particular on instrumental effects which break the factorization of the particle pair detection efficiency, and describe a technique to recover the robustness of correlation observables. We finally introduce a multidimensional weight method to correct for efficiencies that vary simultaneously with particle pseudo rapidity, azimuthal angle, transverse momentum, and the collision vertex position. The method can be generalized to account for any number of "event variables" that may break the factorability of the pair efficiency.

Ravan, Shantam; Pujahari, Prabhat; Prasad, Sidharth; Pruneau, Claude A.

2014-02-01

265

Variable angle correlation spectroscopy  

SciTech Connect

In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with {sup 13}C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system.

Lee, Y.K. [Univ. of California, Berkeley, CA (United States)]|[Lawrence Berkeley Lab., CA (United States). Chemical Biodynamics Div.

1994-05-01

266

No correlation between the diversity and productivity of assemblages: evidence from the phytophage and predator assemblages in various cotton agroecosystems.  

PubMed

Biodiversity research has shown that primary productivity increases with plant species number, especially in many experimental grassland systems. Here, we assessed the correlation between productivity and diversity of phytophages and natural enemy assemblages associated with planting date and intercropping in four cotton agroecosystems. Twenty-one pairs of data were used to determine Pearson correlations between species richness, total number of individuals, diversity indices and productivity for each assemblage every five days from 5 June to 15 September 2012. At the same trophic level, the productivity exhibited a significant positive correlation with species richness of the phytophage or predator assemblage. A significant correlation was found between productivity and total number of individuals in most cotton fields. However, no significant correlations were observed between productivity and diversity indices (including indices of energy flow diversity and numerical diversity) in most cotton fields for either the phytophage or the predator assemblages. Species richness of phytophage assemblage and total individual numbers were significantly correlated with primary productivity. Also, species richness of natural enemy assemblage and total number of individuals correlated with phytophage assemblage productivity. A negative but not significant correlation occurred between the indices of numerical diversity and energy flow diversity and lower trophic-level productivity in the cotton-phytophage and phytophage-predator assemblages for most intercropped cotton agroecosystems. Our results clearly showed that there were no correlations between diversity indices and productivity within the same or lower trophic levels within the phytophage and predator assemblages in cotton agroecosystems, and inter-cropped cotton fields had a stronger ability to support the natural enemy assemblage and potentially to reduce phytophages. PMID:25129809

Gao, Feng; Men, XingYuan; Ge, Feng

2014-09-01

267

Isometric hand grip strength correlated with isokinetic data of the shoulder stabilizers in individuals with chronic stroke.  

PubMed

The purpose of this study was to examine the relationships between isometric hand grip (HG) strength and isokinetic strength data of the glenoumeral and scapulothoracic muscles in 12 individuals with chronic hemiparesis due to stroke. Measures of maximal grip strength were obtained on the HG dynamometer Jamar(®). Isokinetic measures of peak torque and work during shoulder rotations and scapular protraction-retraction movements were obtained with the isokinetic dynamometer at a speed of 60°/s. Pearson correlation coefficients between isometric HG and isokinetic strength data ranged between 0.60 and 0.82 for the peak torque and between 0.59 and 0.86 for the isokinetic work. The findings suggested that, in absence of isokinetic dynamometers, isometric HG strength measurements could be clinically used to monitor strength levels of the shoulder stabilizers and to guide load progressions during strengthening interventions for people with chronic hemiparesis. PMID:22703736

Nascimento, Lucas Rodrigues; Polese, Janaine Cunha; Faria, Christina D C M; Teixeira-Salmela, Luci Fuscaldi

2012-07-01

268

Distinctive Clinical Correlates of Psychotic Major Depression: The CRESCEND Study  

PubMed Central

Objective The purpose of this investigation was to identify distinctive clinical correlates of psychotic major depression (PMD) as compared with non-psychotic major depression (NPMD) in a large cohort of Korean patients with major depressive disorder (MDD). Methods We recruited 966 MDD patients of age over 18 years from the Clinical Research Center for Depression of South Korea (CRESCEND) study. Diagnoses of PMD (n=24) and NPMD (n=942) were made with the DSM-IV definitions and confirmed with SCID. Psychometric scales were used to assess overall psychiatric symptoms (BPRS), depression (HAMD), anxiety (HAMA), global severity (CGI-S), suicidal ideation (SSI-Beck), functioning (SOFAS), and quality of life (WHOQOL-BREF). Using independent t-tests and ?2 tests, we compared clinical characteristics of patients with PMD and NPMD. A binary logistic regression model was constructed to identify factors independently associated with increased likelihood of PMD. Results PMD subjects were characterized by a higher rate of inpatient enrollment, and higher scores on many items on BPRS (somatic concern, anxiety, emotional withdrawal, guilt feelings, tension, depression, suspiciousness, hallucination, motor retardation, blunted affect and excitement) global severity (CGI-s), and suicidal ideation (SSI-Beck). The explanatory factor model revealed that high levels of tension, excitement, and suicidal ideation were associated with increased likelihood of PMD. Conclusion Our findings partly support the view that PMD has its own distinctive clinical manifestation and course, and may be considered a diagnostic entity separate from NPMD. PMID:25110501

Park, Seon-Cheol; Lee, Hwa-Young; Sakong, Jeong-Kyu; Jun, Tae-Youn; Lee, Min-Soo; Kim, Jae-Min; Kim, Jung-Bum; Yim, Hyeon-Woo

2014-01-01

269

Physiological correlates of insomnia.  

PubMed

Insomnia is a prevalent sleep disorder that is typically comorbid with medical, psychiatric, and other sleep disorders. Yet, it is a disorder with its own course and morbidity that can persist if untreated. This chapter describes the physiological correlates of insomnia expressed during sleep and during the daytime. Together, the data from nighttime and daytime electrophysiology, event-related brain potential recording, neuroimaging studies, sympathetic nervous system, and HPA axis monitoring all suggest that insomnia is a 24 h disorder of hyperarousal. PMID:24920447

Roehrs, Timothy; Gumenyuk, Valentina; Drake, Christopher; Roth, Thomas

2014-01-01

270

Flatbands under Correlated Perturbations  

NASA Astrophysics Data System (ADS)

Flatband networks are characterized by the coexistence of dispersive and flatbands. Flatbands (FBs) are generated by compact localized eigenstates (CLSs) with local network symmetries, based on destructive interference. Correlated disorder and quasiperiodic potentials hybridize CLSs without additional renormalization, yet with surprising consequences: (i) states are expelled from the FB energy EFB, (ii) the localization length of eigenstates vanishes as ? ˜1 /ln (E -EFB) , (iii) the density of states diverges logarithmically (particle-hole symmetry) and algebraically (no particle-hole symmetry), and (iv) mobility edge curves show algebraic singularities at EFB . Our analytical results are based on perturbative expansions of the CLSs and supported by numerical data in one and two lattice dimensions.

Bodyfelt, Joshua D.; Leykam, Daniel; Danieli, Carlo; Yu, Xiaoquan; Flach, Sergej

2014-12-01

271

Human coronary plaque wall thickness correlated positively with flow shear stress and negatively with plaque wall stress: an IVUS-based fluid-structure interaction multi-patient study  

PubMed Central

Background Atherosclerotic plaque progression and rupture are believed to be associated with mechanical stress conditions. In this paper, patient-specific in vivo intravascular ultrasound (IVUS) coronary plaque image data were used to construct computational models with fluid-structure interaction (FSI) and cyclic bending to investigate correlations between plaque wall thickness and both flow shear stress and plaque wall stress conditions. Methods IVUS data were acquired from 10 patients after voluntary informed consent. The X-ray angiogram was obtained prior to the pullback of the IVUS catheter to determine the location of the coronary artery stenosis, vessel curvature and cardiac motion. Cyclic bending was specified in the model representing the effect by heart contraction. 3D anisotropic FSI models were constructed and solved to obtain flow shear stress (FSS) and plaque wall stress (PWS) values. FSS and PWS values were obtained for statistical analysis. Correlations with p?correlation between wall thickness and flow shear stress. The mean Pearson correlation r-value was 0.278?±?0.181. Similarly, 9 out of the 10 patients showed negative correlation between wall thickness and plaque wall stress. The mean Pearson correlation r-value was -0.530?±?0.210. Conclusion Our results showed that plaque vessel wall thickness correlated positively with FSS and negatively with PWS. The patient-specific IVUS-based modeling approach has the potential to be used to investigate and identify possible mechanisms governing plaque progression and rupture and assist in diagnosis and intervention procedures. This represents a new direction of research. Further investigations using more patient follow-up data are warranted. PMID:24669780

2014-01-01

272

Are secular correlations between sunspots, geomagnetic activity, and global temperature significant?  

USGS Publications Warehouse

Recent studies have led to speculation that solar-terrestrial interaction, measured by sunspot number and geomagnetic activity, has played an important role in global temperature change over the past century or so. We treat this possibility as an hypothesis for testing. We examine the statistical significance of cross-correlations between sunspot number, geomagnetic activity, and global surface temperature for the years 1868-2008, solar cycles 11-23. The data contain substantial autocorrelation and nonstationarity, properties that are incompatible with standard measures of cross-correlational significance, but which can be largely removed by averaging over solar cycles and first-difference detrending. Treated data show an expected statistically- significant correlation between sunspot number and geomagnetic activity, Pearson p < 10-4, but correlations between global temperature and sunspot number (geomagnetic activity) are not significant, p = 0.9954, (p = 0.8171). In other words, straightforward analysis does not support widely-cited suggestions that these data record a prominent role for solar-terrestrial interaction in global climate change. With respect to the sunspot-number, geomagnetic-activity, and global-temperature data, three alternative hypotheses remain difficult to reject: (1) the role of solar-terrestrial interaction in recent climate change is contained wholly in long-term trends and not in any shorter-term secular variation, or, (2) an anthropogenic signal is hiding correlation between solar-terrestrial variables and global temperature, or, (3) the null hypothesis, recent climate change has not been influenced by solar-terrestrial interaction. ?? 2011 by the American Geophysical Union.

Love, J.J.; Mursula, K.; Tsai, V.C.; Perkins, D.M.

2011-01-01

273

Impact and correlation of environmental conditions on pollen counts in karachi, pakistan.  

PubMed

A quantitative and qualitative survey of airborne pollen was performed in the city of Karachi, and the pollen counts were correlated with different climatic conditions. The aim of the study was to determine the possible effect of meteorological factors on airborne pollen distribution in the atmosphere of Karachi city. Pollen sampling was carried out by using Burkard spore Trap for the period of August 2009 to July 2010, and a total of 2,922 pollen grains/m3 were recorded. In this survey, 22 pollen types were recognized. The highest pollen count was contributed by Poaceae pollen type (1,242 pollen grains/m3) followed by Amaranthaceae/Chenopodiaceae (948 pollen grains/m3), Cyperus rotundus (195 pollen grains/m3) and Prosopis juliflora (169 pollen grains/m3). Peak pollen season was in August showing a total of 709 pollen grains/m3 and lowest pollen count was observed in January-2010. Pearson's chi-square test was performed for the possible correlation of pollen counts and climatic factors. The test revealed significant positive correlation of wind speed with pollen types of Amaranthaceae/Chenopodiaceae; Brassica campestris; Asteraceae; and Thuja orientalis. While the correlation of "average temperature" showed significant positive value with Asteraceae and Tamarix indica pollen types. Negative correlation was observed between humidity/ precipitation and pollen types of Brassica campestris; Daucus carota; Ephedra sp.; and Tamarix indica. In the light of above updated data one could identify various aeroallergens present in the air of Karachi city. PMID:25530143

Perveen, Anjum; Khan, Muneeba; Zeb, Shaista; Imam, Asif Ali

2015-02-01

274

Decreased Serum Hepcidin Concentration Correlates with Brain Iron Deposition in Patients with HBV-Related Cirrhosis  

PubMed Central

Purpose Excessive brain iron accumulation contributes to cognitive impairments in hepatitis B virus (HBV)-related cirrhotic patients. The underlying mechanism remains unclear. Hepcidin, a liver-produced, 25-aminoacid peptide, is the major regulator of systemic iron metabolism. Abnormal hepcidin level is a key factor in some body iron accumulation or deficiency disorders, especially in those associated with liver diseases. Our study was aimed to explore the relationship between brain iron content in patients with HBV-related cirrhosis and serum hepcidin level. Methods Seventy HBV-related cirrhotic patients and forty age- sex-matched healthy controls were enrolled. Brain iron content was quantified by susceptibility weighted phase imaging technique. Serum hepcidin as well as serum iron, serum transferrin, ferritin, soluble transferrin receptor, total iron binding capacity, and transferrin saturation were tested in thirty cirrhotic patients and nineteen healthy controls. Pearson correlation analysis was performed to investigate correlation between brain iron concentrations and serum hepcidin, or other iron parameters. Results Cirrhotic patients had increased brain iron accumulation compared to controls in the left red nuclear, the bilateral substantia nigra, the bilateral thalamus, the right caudate, and the right putamen. Cirrhotic patients had significantly decreased serum hepcidin concentration, as well as lower serum transferring level, lower total iron binding capacity and higher transferrin saturation, compared to controls. Serum hepcidin level negatively correlated with the iron content in the right caudate, while serum ferritin level positively correlated with the iron content in the bilateral putamen in cirrhotic patients. Conclusions Decreased serum hepcidin level correlated with excessive iron accumulation in the basal ganglia in HBV-related cirrhotic patients. Our results indicated that systemic iron overload underlined regional brain iron repletion. Serum hepcidin may be a clinical biomarker for brain iron deposition in cirrhotic patients, which may have therapeutic potential. PMID:23776499

Liu, Jian-Ying; He, Yi-Feng; Dai, Zhi; Chen, Cai-Zhong; Cheng, Wei-Zhong; Zhou, Jian; Wang, Xin

2013-01-01

275

Correlation between serum leptin level and thyroid hormones in children with major beta-thalassemia   

PubMed Central

Background Beta-thalassemia is the most common hematology disease in human and leptin is one of the hormone that produce by adiposities cells. The purpose of this study was to investigate the relationship between serum leptin level and thyroid hormones in children with major beta-thalassemia. Materials and Methods This descriptive-cross sectional study was performed on 90 children aged 6-16 years old with beta-thalassemia. Body Mass Index (BMI ) were meuseurd in all patients and then, after collecting the samples, leptin and thyroid hormones levels of the serum were measured in the patients with thalassemia via ELISA method. Then, all data was analyzed by Pearson correlation test, and x2 statistical tests and P < 0.05 was considered as a significant difference. Results The mean of body mass index and serum leptin level in the patients group was 16.58±2.43 and 1.521 ±2. 49, respectively. The mean serum levels of thyroxin (T4), triiodothyronine (T3), and thyroid- stimulating hormone (TSH) in patient's groups were7.94 ±3.56, 1.28 ± 0.46, and 2.85 ±3. 44, respectively. There was significant correlation between serum leptin levels and T4 in patients with major thalassemia; also there was no significant correlation between serum leptin level and T3and TSH. There was a significant correlation was between the leptin serum level and BMI in patients (P value=0.008). Conclusion The results of this study demonstrated that in patients with major thalassemia, there was significant correlation between serum leptin level and thyroxin hormone. Leptin level has more relationship with thyroxin than thyroid- stimulating hormone. PMID:24575288

Shahramian, I; Noori, NM; Ramezani, AA; Sharafi, E; Akhlaghi, E

2013-01-01

276

Correlation of Advanced Glycation Endproducts Estimated From Skin Fluorescence in First-Degree Relatives: The Impact of Adjustment for Skin Pigmentation.  

PubMed

The objective was to assess the relationship of skin advanced glycation endproducts (AGEs) between first-degree relatives estimated from skin fluorescence (SF) after adjustment for skin pigmentation. SF was excited by LEDs centered at 375, 405, and 420 nm from children with type 1 diabetes and their mothers. Data were adjusted to generate measures of skin intrinsic fluorescence (SIF) at the various excitation wavelengths, using 2 different pairs of correction coefficients for excitation (kx) and emission (km): kx = 0.5, km = 0.5 (not associated with skin pigmentation) and kx = 1.0, km = 0.0 (strongly associated with skin pigmentation). Pearson correlation analysis was performed, as well as a multiple variable analysis with maternal SIF adjusted for the effects of maternal age and race. There were 50 matched pairs of children and their mothers. Children were 13.3 ± 3.7 years of age and there were 19 boys/31 girls and 15 black/35 white. Mothers were 41.8 ± 6.8 years of age. The age of mother and child was highly correlated, r = .64, P < .0001. In Pearson correlation analysis, child's SIF (kx = 1.0, km = 0.0) the had strongest association with maternal SIF, while with SIF (kx = 0.5, km = 0.5) there was a trend for association. In the multiple variable model child SIF was associated with maternal SIF for all corrections and wavelengths but was stronger for kx = 1.0, km = 0.0. Even after adjustment for skin pigmentation and race, correlation of SIF between family members persists, suggesting that other genetic and/or environmental factors shared by parent and child may influence estimated skin AGEs. PMID:25411062

Báez, Eileen A; Shah, Shreepal; Felipe, Dania; Maynard, John; Chalew, Stuart

2014-11-18

277

Correlative Measurements Program  

NASA Technical Reports Server (NTRS)

The GSFC Correlative Measurements Program at the Wallops Flight Facility was represented on the Satellite/Satellite Intercomparisons Working Group. The Correlative Measurements Program uses the Rocket Ozonesonde (ROCOZ-A) and the Electrochemical Concentration Cell (ECC) balloon borne ozonesonde to measure the vertical profile of ozone amount in the atmosphere. The balloon work is described in a separate report. The ROCOZ-A instrument was used for many years to provide in situ truth data for various satellite ozone measuring systems, such as SBUV on Nimbus-7, SAGE-II, SBUV-II on the NOAA series of polar orbiting satellites, SME, LIMS, etc. The particular data sets of interest to the Ozone Trends Panel Working Group were collected at Natal, Brazil. The major results produced for and used by the Ozone Trends Panel are shown. The ROCOZ-A average ozone density profile is plotted versus altitude on the left. ECC ozonesondes were used for the portion of the profile below 20 km, the lower limit for ROCOZ-A. The difference between SAGE-II and ROCOZ-A average density profiles is shown.

Parsons, C. L.

1988-01-01

278

Nonlinear Fourier correlation  

NASA Astrophysics Data System (ADS)

Fourier correlators perform space-invariant linear filtering on all input points, so they can identify and locate patterns in parallel. Each output point is a weighted sum of components of the Fourier transform of the input, so the discriminants used are inherently linear. As most practical problems are not linearly discriminable, that causes a problem. This paper describes a quite general solution involving nonlinear combining of nonlinearly processed outputs from multiple Fourier masks. The design of the masks and nonlinearities allows very powerful nonlinear discrimination that preserves the space-invariant feature that makes Fourier correlators attractive. Given a set of target-class images, henceforth referred to as the training set or trainers, the algorithm developed herein computes an ordered set of classifier filters - Generalized Matched Filters (GMFs) threshold values. An unlabeled image is applied to the classifier filter set, hereafter referred to as super-generalized matched filter (SGMF). If the peak response of any of the classifier filters (GMFs) to the unlabeled test image exceeds the threshold level the decision is made in favor of labeling the image as target-class otherwise it is labeled non-target- class.

Heidary, Kaveh; Caulfield, H. John

2009-04-01

279

Multichannel analysis of correlation length of SEVIRI images around ground-based cloud observatories to determine their representativeness  

NASA Astrophysics Data System (ADS)

Images of the geostationary Meteosat-9 SEVIRI instrument during the year 2012 are analyzed with respect to the representativeness of the observations of eight cloud observatories in Europe. Cloudy situations are selected to get a time series for every pixel in a 300 km × 300 km area centered around each ground station. Then the Pearson correlation coefficient of each time series to the one of the pixel nearest to the corresponding ground site is calculated. The area for which a station is representative is defined by the characteristic radius around each station for each SEVIRI channel, where the average correlation falls below 0.9. It is found that measurements in the visible and near infrared channels, which respond to cloud microphysics, are correlated in an area with a 1 to 4 km radius, while the thermal channels, that correspond to cloud top temperature, are correlated to a distance of about 20 km. The defined radius even increases for the water vapor and ozone channels. While all stations in Central Europe are quite alike, the correlations around the station in the mountains of southern Italy are much lower. Additionally correlations at different distances corresponding to the grid box sizes of forecast models were compared. The results show good comparability between regional forecast models (grid size ? 10 km) and ground-based measurements since the correlations in less than 10 km distance are in all cases higher than 0.8. For larger distances like they are typical for global models (grid size ? 20 km) the correlations decrease to 0.6, especially for shortwave measurements and corresponding cloud products. By comparing daily means, the characteristic radius of each station is increased to about 3 to 10 times the value of instantaneous measurements and also the comparability to models grows.

Slobodda, J.; Hünerbein, A.; Lindstrot, R.; Preusker, R.; Ebell, K.; Fischer, J.

2014-06-01

280

Correlation Between Hypertension, C-Reactive Protein and Serum Uric Acid With Psychological Well-being  

PubMed Central

Background: Multiple population-based human studies have established a strong association between increasing levels of serum C-reactive protein, uric acid and subsequent development of hypertension. Objectives: We aimed to investigate the association between mental well-being with presence of hypertension, hyperuricemia and hs-CRP levels. ?? Patients and Methods: This was a cross sectional study of 801 individuals aged 35-85 years old in Broujerd, Iran, included by randomized cluster sampling. General Health Questionnaire (GHQ-12) for assessing mental health/distress level, MONICA standard questions for evaluating hypertension history, serum hs-CRP and Serum Uric Acid (SUA) were evaluated Data were analyzed by appropriate statistical test such as chi-square, T-test and correlation. Results: One hundred eighty five patients (23.1%) had high distress/minor psychiatric disorders. SUA had significant association with hypertension (r = 0.64, P = 0.034). No significant relation was observed between hs-CRP and hypertension. The correlation between GHQ and hs-CRP was not significant but a weak and negative correlation was found between GHQ and SUA SUA (P = 0.012, r = -0.089). Conclusions: The weak and strong correlation among these parameters indicate that mental wellbeing relays on physical wellness and interact with each other; therefore, controlling hypertension along with uric acid control may effect mental health of any kind of patients. PMID:25237581

Maleki, Ali; Samandari, Saeid; Almeida, Osvaldo; Jafarian Kerman, Scott Reza; Abdolvand, Mahdi; Aliyari, Farshid; Foroughi, Saeid

2014-01-01

281

Magnitude correlations in global seismicity  

SciTech Connect

By employing natural time analysis, we analyze the worldwide seismicity and study the existence of correlations between earthquake magnitudes. We find that global seismicity exhibits nontrivial magnitude correlations for earthquake magnitudes greater than M{sub w}6.5.

Sarlis, N. V. [Solid State Section and Solid Earth Physics Institute, Physics Department, University of Athens, Panepistimiopolis, Zografos GR-157 84, Athens (Greece)

2011-08-15

282

Correlation of the LNNB-III with the WAIS-III in a mixed psychiatric and brain-injured population.  

PubMed

The purpose of the study was to examine the relationship between the Luria-Nebraska Neuropsychological Battery-Third Edition (LNNB-III) and the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III). Participants were 85 adults referred for neuropsychological evaluation. The mean age of participants was 38.73 years (SD = 16.54) and average education was 13.07 years (SD = 2.60). The sample was predominantly female (52.9%), right-handed (86.3%), and Caucasian (68.6%), with the remainder of the population classified as Hispanic (13.7%), African-American (5.9%), or other (11.8%). Diagnoses included 26% psychiatric disorders, 64% neurological disorders, and 10% with no diagnosis. Pearson product correlation yielded a number of significant relationships between the WAIS-III IQ scores and the LNNB-III scales. The highest correlations were with the LNNB Intelligence, Visual-Spatial, Complex Auditory, and Arithmetic scales. Additionally, significant correlations were found between the WAIS-III subtests and a moderate proportion of the LNNB-III subtests. Correlations were also reported for the new WAIS-III scales, Letter-Number Sequencing and Matrix Reasoning. The results suggest that similar abilities are being assessed on both tests. These findings allow clinicians to not only evaluate the consistency of performance across this testing battery, but provide a useful screening instrument for intelligence. PMID:11912678

Devaraju-Backhaus, S; Espe-Pfeifer, P; Mahrou, M L; Golden, C J

2001-01-01

283

Plasma 1,8-cineole correlates with cognitive performance following exposure to rosemary essential oil aroma  

PubMed Central

Objective The mode of influence of the aromas of plant essential oils on human behaviour is largely unclear. This study was designed to assess the potential pharmacological relationships between absorbed 1,8-cineole following exposure to rosemary aroma, cognitive performance and mood. Methods Twenty healthy volunteers performed serial subtraction and visual information processing tasks in a cubicle diffused with the aroma of rosemary. Mood assessments were made pre and post testing, and venous blood was sampled at the end of the session. Pearson correlations were carried out between serum levels of 1,8-cineole, cognitive performance measures and change in mood scores. Results Here we show for the first time that performance on cognitive tasks is significantly related to concentration of absorbed 1,8-cineole following exposure to rosemary aroma, with improved performance at higher concentrations. Furthermore, these effects were found for speed and accuracy outcomes, indicating that the relationship is not describing a speed–accuracy trade off. The relationships between 1,8-cineole levels and mood were less pronounced, but did reveal a significant negative correlation between change in contentment and plasma 1,8-cineole levels. Conclusion These findings suggest that compounds absorbed from rosemary aroma affect cognition and subjective state independently through different neurochemical pathways. PMID:23983963

Oliver, Lorraine

2012-01-01

284

Correlates of Hepcidin and NTBI according to HFE Status in Patients Referred to a Liver Centre.  

PubMed

Background/Aims: Innately low hepcidin levels lead to iron overload in HFE-associated hereditary haemochromatosis. Methods: This study compared hepcidin and non-transferrin bound iron (NTBI) levels in untreated iron-loaded and non-iron-loaded C282Y homozygotes to levels in C282Y/H63D compound heterozygotes and individuals with other HFE genotypes associated with less risk of iron overload. Results: As the genotypic risk for iron overload increased, transferrin saturation and serum NTBI levels increased while serum hepcidin levels decreased. Overweight and obese male C282Y homozygotes had significantly higher hepcidin levels than male C282Y homozygotes with a normal BMI. Pearson product-moment analysis showed that serum hepcidin levels significantly correlated with HFE status, serum ferritin, age, NTBI, transferrin saturation, gender and BMI. Subsequent multiple regression analysis showed that HFE status and serum ferritin were significant independent correlates of serum hepcidin levels. Conclusions: In summary, this study has shown that while serum ferritin and HFE status are the most important determinants of hepcidin levels, factors such age, gender, BMI, transferrin saturation and NTBI all interact closely in the matrix of homeostatic iron balance. © 2014 S. Karger AG, Basel. PMID:25277871

Ryan, Eleanor; Ryan, John D; Russell, Jennifer; Coughlan, Barbara; Tjalsma, Harold; Swinkels, Dorine W; Stewart, Stephen; Crowe, John P

2014-09-26

285

Correlation between Duffy blood group phenotype and breast cancer incidence  

PubMed Central

Background Different ethnicities have different distribution of Duffy blood group (DBG) phenotypes and different breast cancer morbidity. A study in our lab demonstrated that Duffy antigen/receptor for chemokines (DARC, also known as DBGP, the Duffy protein phenotype), led to the inhibition of tumorigenesis. Therefore, we tested the hypothesis that DBGP is correlated with breast cancer occurrence. Methods DBGP proteins were examined by indirect antiglobulin testing with anti-FYa and anti-FYb antibodies. The phenotypes were classified into four groups according to the agglutination reactions: FYa + FYb+, FYa + FYb-, FYa-FYb + and FYa-FYb-. The phenotypes and pathological diagnosis of consecutively hospitalized female patients (n = 5,022) suffering from breast cancer at the Shanghai Cancer Hospital and Henan Province Cancer Hospital were investigated. The relationships between DBGP expression with breast cancer occurrence, axillary lymph status, histological subtype, tumor size pathological grade and overall survival were analyzed. Results The incidence of breast cancer was significantly different between FYa + FYb + (29.8%), FYa + FYb- (33.2%), FYa-FYb + (45.6%) and FYa-FYb- (59.1%; P = 0.001). Significant different numbers of breast cancer patients had metastases to the axillary lymph nodes in the FYa + FYb + group (25.1%), FYa + FYb- (36.9%), FYa-FYb + (41.0%) and FYa-FYb- (50.0%, (P = 0.005). There was a statistical significance (p = 0.022) of the overall survival difference between patients with difference phenotypes. No significant difference was observed in cancer size (t-test, p > 0.05), histological cancer type (Fisher's exact test, p > 0.05) or histological grade (Fisher's exact test, p > 0.05) between every each DBGP group. Conclusions DBGP is correlated with breast cancer incidence and axillary lymph node metastasis and overall survival. Further investigations are required to determine the underlying mechanism of Duffy blood group phenotype on breast cancer risk. PMID:22928984

2012-01-01

286

Abdominal Wall Endometrioma: Ultrasonographic Features and Correlation with Clinical Findings  

PubMed Central

Background: The diagnosis of abdominal wall endometrioma (AWE) is often confused with other surgical conditions. Certain factors relating to knowledge of the clinical history of the disease make correct diagnosis and treatment difficult. Aims: To present the clinical findings and ultrasonographic (US) features of AWE with special emphasis on size-related features. Study Design: This study reviewed abdominal wall endometriomas during a 2-year period in the Radiology Department of Sifa University Hospital, Izmir. Methods: Eleven women (mean age 32.6 years) with 12 scar endometriomas (mean diameter 29.2 mm) were consecutively evaluated by US and Colour Doppler examination (CDUS) prior to surgery. Lesions were grouped into large (?3 cm) and small nodules. Vascularisation was classified as location (central, peripheral and mixed) and severity (absent, moderately vascular and hypervascular). In each patient, the nature of pain (absent, cyclic: associated with menstruation and continuous), historical and clinical data were documented. Four patients underwent Magnetic Resonance Imaging and their findings were presented. Fisher’s exact test, ?2 test for categorical data and the unpaired T-test for continuous variables were used for statistical analysis. Results: In all the women, US of the AWE showed the presence of a solid hypoechoic mass (less echogenic than the surrounding hyperechoic fat) within the abdominal wall. There was a significant correlation between AWE sizes with repeated caesareans and the mean time between the last operation and admission to hospital (p<0.05). Large endometriomas showed increased central vascularity (p<0.05). Cyclic pain was more frequent in small lesions, whereas continuous pain was more commonly found in patients with larger lesions (p<0.05). Conclusion: AWE is often misdiagnosed clinically because endometriosis may occur years after the caesarean section, the pain is often non-cyclic in nature, and there is not always a palpable tender mass. The sonographic and Doppler findings, along with proper correlation with clinical data, may substantially contribute to the correct diagnosis of endometrioma. PMID:25207093

Solak, Aynur; Genç, Berhan; Yalaz, Seyhan; ?ahin, Neslin; Sezer, Taylan Özgür; Solak, ?lhami

2013-01-01

287

The CARMA Correlator  

NASA Astrophysics Data System (ADS)

We describe the software development effort for the first-light correlator of the Combined Array for Research in Millimeter-wave Astronomy (CARMA{http://www.mmarray.org/}), the merger of the Owens Valley Radio Observatory (OVRO{http://www.ovro.caltech.edu/}) and Berkeley-Illinois-Maryland Association (BIMA{http://bima.astro.umd.edu/}) millimeter arrays that is expected to reach first-light in 2005. The digital hardware relies on programmable logic devices (FPGAs), signal processors (DSPs), and Linux-based host computers acting in concert to produce baseline visibility data. We summarize the hardware configuration, the distribution of computational tasks among components, and the tools and techniques used to program these devices.

Rauch, K. P.; Hobbs, R.; Hawkins, D. W.

2005-12-01

288

Flatbands under Correlated Perturbations.  

PubMed

Flatband networks are characterized by the coexistence of dispersive and flatbands. Flatbands (FBs) are generated by compact localized eigenstates (CLSs) with local network symmetries, based on destructive interference. Correlated disorder and quasiperiodic potentials hybridize CLSs without additional renormalization, yet with surprising consequences: (i) states are expelled from the FB energy E_{FB}, (ii) the localization length of eigenstates vanishes as ??1/ln(E-E_{FB}), (iii) the density of states diverges logarithmically (particle-hole symmetry) and algebraically (no particle-hole symmetry), and (iv) mobility edge curves show algebraic singularities at E_{FB}. Our analytical results are based on perturbative expansions of the CLSs and supported by numerical data in one and two lattice dimensions. PMID:25526142

Bodyfelt, Joshua D; Leykam, Daniel; Danieli, Carlo; Yu, Xiaoquan; Flach, Sergej

2014-12-01

289

Correlates of Desistance  

NSDL National Science Digital Library

Research has shown that marital status and employment are correlates of desistance. That is, adolescents involved with crime were more likely to discontinue offending in adulthood if they were married and had a good job. Most of what criminologists know about the process of desistance from crime is based on a sample of adult males in the 1950's. There is no question that life in America has changed drastically in the past fifty years. Given the importance of examining historical change inherent in the life course perspective, it is important to determine how changes in the social structure over time impact individuals. Therefore, the goals of this data analysis exercise are to examine changes in marriage and employment over the last fifty years. The purposes are to identify the changes that have taken place, and to hypothesize how these changes may affect the process of desistance from crime today.

Ford, Jason

2009-08-17

290

Abundance correlations among comets  

NASA Technical Reports Server (NTRS)

Results of narrowband filter photometry are presented for comets 1977g, 1978b, 1978f, 1978j, 1979c, and 1979i. There appears to be a remarkable homogeneity among comets with regard to the relative production rates for those species which are readily measured, specifically C2, CN, C3, and OH. Most comets appear to show identical relative abundances, except for a rather well-defined variation with heliocentric distance. Molecular production rates appear to be unrelated to either the emission-to-continuum (gas-to-dust) ratio or the dynamical age of the comet. The correlation with visual magnitudes is excellent, though the slope is not what could be intuitively expected.

Ahearn, M. F.; Millis, R. L.

1980-01-01

291

Strongly Correlated Electronic Systems  

NASA Astrophysics Data System (ADS)

This dissertation presents several explorations into the field of many-body physics. In chapters 1-3 the fundamental nature of many-body interactions in quantum antiferromagnets is scrutinized. Chapter 1 surveys the modern theory of magnetic insulators, focusing on quantum antiferromagnets. Chapter 2 presents an improved method for computing expectation values of local operators in fully Gutzwiller -projected variational states. This embedded cluster method allows accurate extrapolation to the thermodynamic limit when the correlations are sufficiently short-range. The method is used to calculate static spin-spin correlations in a variety of one- and two-dimensional variational states for quantum antiferromagnets. Section 2.3.3 presents a study of the Heisenberg spin Hamiltonian on several lattices using Gutzwiller-projected variational wavefunctions with non-zero Neel order. The variational energies are comparable to more sophisticated calculations, suggesting that these variational wavefunctions are close to the true ground state wavefunction of the Heisenberg antiferromagnet. Chapter 3 discusses Gutzwiller-projected variational wavefunctions for charged, spinless holon excitations in chiral spin liquids. We find that these states describe anyons, with a statistical phase Phi_ {s} that is continuously adjustable between 0 and pi/2, depending on a variational parameter. The statistical flux attached to each holon is localized to within a lattice constant. Chapters 4 and 5 consider a superconducting and a magnetically ordered system, respectively, with the aim of understanding the many-body effects phenomenologically. Chapter 4 presents a self-contained overview of solid Buckminsterfullerene, C_{60}, with an emphasis on those aspects relevant to superconductivity. A BCS theory for superconductivity based on phonon-mediated electron pairing is also presented in some detail. In this model, the isotope effect is the most direct experimental indicator of the role played by phonons in the electron-electron pairing. The superconducting transition temperature of doped C_{60 } is unusually sensitive to partial substitution of ^{13}C for the naturally abundant isotope ^{12}C. Section 4.6 presents the theoretical temperature -dependent resistivity rho(T) resulting from a complete theory of the phonons in rm K_3C_{60} and rm Rb_3C_{60}. The electron-phonon couplings are derived from the theory highlighted in chapter 4. The theory accounts for the unusual non -linear temperature dependence in rho(T). . Finally, chapter 5 reviews several experiments on a variety of magnetic multi-layer and sandwich structures are reviewed. These systems have revealed an indirect exchange coupling between layers of ferromagnets separated by nonmagnetic spacer layers. This coupling oscillates from ferromagnetic to antiferromagnetic depending on the thickness of the spacer layers, with an anomalously long period. (Abstract shortened by UMI.).

Deaven, David Matthew

292

Correlation between vertical misfits and stresses transmitted to implants from metal frameworks.  

PubMed

An inappropriate prosthetic fit could cause stress over the interface implant/bone. The objective of this study was to compare stresses transmitted to implants from frameworks cast using different materials and to investigate a possible correlation between vertical misfits and these stresses. Fifteen one-piece cast frameworks simulating bars for fixed prosthesis in a model with five implants were fabricated and arranged into three different groups according to the material used for casting: CP Ti (commercially pure titanium), Co-Cr (cobalt-chromium) or Ni-Cr-Ti (nickel-chromium-titanium) alloys. Each framework was installed over the metal model with all screws tightened to a 10 N cm torque and then, vertical misfits were measured using an optical microscope. The stresses transmitted to implants were measured using quantitative photoelastic analysis in values of maximum shear stress (?), when each framework was tightened to the photoelastic model to a 10 N cm standardized torque. Stress data were statistically analyzed using one-way ANOVA and Tukey's test and correlation tests were performed using Pearson's rank correlation (? = 0.05). Mean and standard deviation values of vertical misfit are presented for CP Ti (22.40 ± 9.05 ?m), Co-Cr (66.41 ± 35.47 ?m) and Ni-Cr-Ti (32.20 ± 24.47 ?m). Stresses generated by Co-Cr alloy (? = 7.70 ± 2.16 kPa) were significantly higher than those generated by CP Ti (? = 5.86 ± 1.55 kPa, p = 0.018) and Ni-Cr-Ti alloy (? = 5.74 ± 3.05 kPa, p = 0.011), which were similar (p = 0.982). Correlations between vertical misfits and stresses around the implants were not significant as for any evaluated materials. PMID:21497352

de Torres, Erica Miranda; Barbosa, Gustavo Augusto Seabra; Bernardes, Sérgio Rocha; de Mattos, Maria da Glória Chiarello; Ribeiro, Ricardo Faria

2011-06-01

293

Periprostatic Fat Thickness on MRI: Correlation With Gleason Score in Prostate Cancer.  

PubMed

OBJECTIVE. The purpose of this study was to retrospectively evaluate the relationship between periprostatic fat thickness on MRI and Gleason score of prostate cancer using radical prostatectomy as the reference standard. MATERIALS AND METHODS. This study included 190 patients (mean age [± SD], 66.9 ± 7.0 years) who underwent MRI before radical prostatectomy. Two radiologists measured the subcutaneous and periprostatic fat thickness on midsagittal T2-weighted MR images as the shortest perpendicular distance from the pubic symphysis to the skin and prostate, respectively. Subcutaneous and periprostatic fat along with age, height, weight, body mass index, and prostate-specific antigen (PSA) were correlated with Gleason score by using Pearson (r) or Spearman (?) correlation coefficients and compared between low- (Gleason score = 6) and high- (? 7) grade prostate cancer by using univariate and multivariate logistic regression analyses. RESULTS. The mean subcutaneous and periprostatic fat thicknesses were 24.0 ± 8.4 mm and 5.0 ± 2.0 mm, respectively. The Gleason score was significantly correlated with age (? = 0.181, p = 0.012), PSA (? = 0.345, p < 0.001), and periprostatic fat thickness (? = 0.228, p = 0.002). Multivariate analysis revealed that age, height, PSA level, and periprostatic fat thickness (odds ratio, 1.331; 95% CI, 1.063-1.666) were independently predictive of high-grade (p ? 0.013) disease. CONCLUSION. Periprostatic fat thickness on MRI showed a mild to modest but significant correlation with Gleason score of prostate cancer with radical prostatectomy as the reference standard and was an independent predictive factor for high-grade prostate cancer. PMID:25539273

Woo, Sungmin; Cho, Jeong Yeon; Kim, Sang Youn; Kim, Seung Hyup

2015-01-01

294

Correlation between reflux and multichannel intraluminal impedance pH monitoring in untreated volunteers  

PubMed Central

Objective While probable causative agents have been identified (e.g., refluxate components, tobacco smoke), the definitive mechanism for inflammation-related laryngeal mucosal damage remains elusive. Multichannel intraluminal impedance combined with pH monitoring (MII/pH) has emerged as a sensitive tool for diagnosis and characterization of gastroesophageal reflux disease (GERD) with laryngopharyngeal manifestations. To determine the relationship between laryngeal signs and MII/pH, we examined correlations between Reflux Finding Score (RFS) ratings of videostroboscopic laryngeal examinations and findings from MII/pH. Study Design Correlational study. Methods Healthy, untreated volunteers (n =142) underwent reflux diagnosis using data acquired from MII/pH testing. Eight trained clinicians performed RFS ratings of corresponding laryngeal examinations. Averaged RFS ratings were compared to MII/pH data using Pearson correlation coefficients. The relationship between RFS and MII/pH findings and demographic/clinical information (age, sex, smoking status, reflux) was assessed using general linear modeling. Rater reliability was evaluated. Results Posterior commissure hypertrophy was negatively correlated with minutes of nonacid refluxate (R=-0.21, p=0.0115). General linear modeling revealed that 28-40% of the variance in ratings of ventricular obliteration, erythema/hyperemia, vocal fold edema, diffuse laryngeal edema, posterior commissure hypertrophy, and granulation/granuloma could be explained by main and interaction effects of age, sex, smoking status, and reflux. Intra- and inter-rater reliability for RFS were poor-fair. Conclusion These results support the theory that the RFS is not specific for reflux in healthy, untreated volunteers, suggesting there may be alternate explanations for inflammatory clinical signs commonly ascribed to reflux in this population. PMID:24782404

Jetté, Marie E.; Gaumnitz, Eric A.; Birchall, Martin A.; Welham, Nathan V.; Thibeault, Susan L.

2014-01-01

295

Correlation of transcriptomic responses and metal bioaccumulation in Mytilus edulis L. reveals early indicators of stress.  

PubMed

Marine biomonitoring programs in the U.S. and Europe have historically relied on monitoring tissue concentrations of bivalves to monitor contaminant levels and ecosystem health. By integrating 'omic methods with these tissue residue approaches we can uncover mechanistic insight to link tissue concentrations to potential toxic effects. In an effort to identify novel biomarkers and better understand the molecular toxicology of metal bioaccumulation in bivalves, we exposed the blue mussel, Mytilus edulis L., to sub-lethal concentrations (0.54 ?M) of cadmium, lead, and a Cd+Pb mixture. Metal concentrations were measured in gill tissues at 1, 2, and 4 weeks, and increased linearly over the 4 week duration. In addition, there was evidence that Pb interfered with Cd uptake in the mixture treatment. Using a 3025 sequence microarray for M. edulis, we performed transcriptomic analysis, identifying 57 differentially expressed sequences. Hierarchical clustering of these sequences successfully distinguished the different treatment groups demonstrating that the expression profiles were reproducible among the treatments. Enrichment analysis of gene ontology terms identified several biological processes that were perturbed by the treatments, including nucleoside phosphate biosynthetic processes, mRNA metabolic processes, and response to stress. To identify transcripts whose expression level correlated with metal bioaccumulation, we performed Pearson correlation analysis. Several transcripts correlated with gill metal concentrations including mt10, mt20, and contig 48, an unknown transcript containing a wsc domain. In addition, three transcripts directly involved in the unfolded protein response (UPR) were induced in the metal treatments at 2 weeks and were further up-regulated at 4 weeks. Overall, correlation of tissue concentrations and gene expression responses indicates that as mussels accumulate higher concentrations of metals, initial stress responses are mobilized to protect tissues. However, given the role of UPR in apoptosis, it serves as an early indicator of stress, which once overwhelmed will result in adverse physiological effects. PMID:25016106

Poynton, Helen C; Robinson, William E; Blalock, Bonnie J; Hannigan, Robyn E

2014-10-01

296

Correlated stability conjecture revisited  

NASA Astrophysics Data System (ADS)

Correlated stability conjecture (CSC) proposed by Gubser and Mitra (2000, 2001) [1,2] linked the thermodynamic and classical (in)stabilities of black branes. The classical instabilities, whenever occurring, were conjectured to arise as Gregory-Laflamme (GL) instabilities of translationally invariant horizons. In Buchel (2005) [3] it was shown that the thermodynamic instabilities, specifically the negative specific heat, indeed result in the instabilities in the hydrodynamic spectrum of holographically dual plasma excitations. A counter-example of CSC was presented in the context of black branes with scalar hair undergoing a second-order phase transition (Friess et al., 2005 [4]). In this Letter we discuss a related counter-example of CSC conjecture, where a thermodynamically stable translationally invariant horizon has a genuine tachyonic instability. We study the spectrum of quasinormal excitations of a black brane undergoing a continuous phase transition, and explicitly identify the instability. We compute the critical exponents of the critical momenta and the frequency of the unstable fluctuations and identify the dynamical critical exponent of the model.

Buchel, Alex; Pagnutti, Chris

2011-02-01

297

Medial thalamic 18-FDG uptake following inescapable shock correlates with subsequent learned helpless behavior  

SciTech Connect

The learned helplessness paradigm has been repeatedly shown to correlate with neurobiological aspects of depression in humans. In this model, rodents are exposed inescapable foot-shock in order to reveal susceptibility to escape deficit, defined as 'learned helplessness' (LH). Few methods are available to probe the neurobiological aspects underlying the differences in susceptibility in the living animal, thus far being limited to studies examining regional neurochemical changes with microdialysis. With the widespread implementation of small animal neuroimaging methods, including positron emission tomography (PET), it is now possible to explore the living brain on a systems level to define regional changes that may correlate with vulnerability to stress. In this study, 12 wild type Sprague-Dawley rats were exposed to 40 minutes of inescapable foot-shock followed by metabolic imaging using 2-deoxy-2[{sup 18}F]fluoro-D-glucose (18-FDG) 1 hour later. The escape test was performed on these rats 48 hours later (to accommodate radiotracer decay), where they were given the opportunity to press a lever to shut off the shock. A region of interest (ROI) analysis was used to investigate potential correlations (Pearson Regression Coefficients) between regional 18-FDG uptake following inescapable shock and subsequent learned helpless behavior (time to finish the test; number of successful lever presses within 20 seconds of shock onset). ROI analysis revealed a significant positive correlation between time to finish and 18-FDG uptake, and a negative correlation between lever presses and uptake, in the medial thalamic area (p=0.033, p=0.036). This ROI included the paraventricular thalamus, mediodorsal thalamus, and the habenula. In an effort to account for possible spillover artifact, the posterior thalamic area (including ventral medial and lateral portions) was also evaluated but did not reveal significant correlations (p=0.870, p=0.897). No other significant correlations were found in additional regions analyzed including the nucleus accumbens, caudate putamen, substantia nigra, and amygdala. These data suggest that medial thalamic 18-FDG uptake during inescapable shock may contribute to subsequent escape deficits, and are not confounded by shock effects per se, since all animals received the same treatment prior to scanning. We have previously explored 18-FDG differences following the escape test session which also showed hyperactivity in the medial thalamus of learned helpless animals compared to non-learned helpless, and included additional cortical-limbic changes. Given the neuroanatomical connections between the medial thalamus (and habenula) with the prefrontal cortex and monoaminergic brain stem, one possible speculation is that abnormal neuronal activity in these areas during stress may set in motion circuitry changes that correlate with learned helpless behavior.

Mirrione,M.M.; Mirrione, M.M.; Schulz, D.; Dewey, S.L.; Henn, F.A.

2009-12-06

298

The Murchison Widefield Array Correlator  

E-print Network

The Murchison Widefield Array (MWA) is a Square Kilometre Array (SKA) Precursor. The telescope is located at the Murchison Radio--astronomy Observatory (MRO) in Western Australia (WA). The MWA consists of 4096 dipoles arranged into 128 dual polarisation aperture arrays forming a connected element interferometer that cross-correlates signals from all 256 inputs. A hybrid approach to the correlation task is employed, with some processing stages being performed by bespoke hardware, based on Field Programmable Gate Arrays (FPGAs), and others by Graphics Processing Units (GPUs) housed in general purpose rack mounted servers. The correlation capability required is approximately 8 TFLOPS (Tera FLoating point Operations Per Second). The MWA has commenced operations and the correlator is generating 8.3 TB/day of correlation products, that are subsequently transferred 700 km from the MRO to Perth (WA) in real-time for storage and offline processing. In this paper we outline the correlator design, signal path, and proce...

Ord, S M; Emrich, D; Pallot, D; Wayth, R B; Clark, M A; Tremblay, S E; Arcus, W; Barnes, D; Bell, M; Bernardi, G; Bhat, N D R; Bowman, J D; Briggs, F; Bunton, J D; Cappallo, R J; Corey, B E; Deshpande, A A; deSouza, L; Ewell-Wice, A; Feng, L; Goeke, R; Greenhill, L J; Hazelton, B J; Herne, D; Hewitt, J N; Hindson, L; Hurley-Walker, H; Jacobs, D; Johnston-Hollitt, M; Kaplan, D L; Kasper, J C; Kincaid, B B; Koenig, R; Kratzenberg, E; Kudryavtseva, N; Lenc, E; Lonsdale, C J; Lynch, M J; McKinley, B; McWhirter, S R; Mitchell, D A; Morales, M F; Morgan, E; Oberoi, D; Offringa, A; Pathikulangara, J; Pindor, B; Prabu, T; Procopio, P; Remillard, R A; Riding, J; Rogers, A E E; Roshi, A; Salah, J E; Sault, R J; Shankar, N Udaya; Srivani, K S; Stevens, J; Subrahmanyan, R; Tingay, S J; Waterson, M; Webster, R L; Whitney, A R; Williams, A; Williams, C L; Wyithe, J S B

2015-01-01

299

SAW correlator spread spectrum receiver  

DOEpatents

A surface acoustic wave (SAW) correlator spread-spectrum (SS) receiver is disclosed which utilizes a first demodulation stage with a chip length n and a second demodulation stage with a chip length m to decode a transmitted SS signal having a code length l=n.times.m which can be very long (e.g. up to 2000 chips or more). The first demodulation stage utilizes a pair of SAW correlators which demodulate the SS signal to generate an appropriate code sequence at an intermediate frequency which can then be fed into the second demodulation stage which can be formed from another SAW correlator, or by a digital correlator. A compound SAW correlator comprising two input transducers and a single output transducer is also disclosed which can be used to form the SAW correlator SS receiver, or for use in processing long code length signals.

Brocato, Robert W

2014-04-01

300

Correlational Effect Size Benchmarks.  

PubMed

Effect size information is essential for the scientific enterprise and plays an increasingly central role in the scientific process. We extracted 147,328 correlations and developed a hierarchical taxonomy of variables reported in Journal of Applied Psychology and Personnel Psychology from 1980 to 2010 to produce empirical effect size benchmarks at the omnibus level, for 20 common research domains, and for an even finer grained level of generality. Results indicate that the usual interpretation and classification of effect sizes as small, medium, and large bear almost no resemblance to findings in the field, because distributions of effect sizes exhibit tertile partitions at values approximately one-half to one-third those intuited by Cohen (1988). Our results offer information that can be used for research planning and design purposes, such as producing better informed non-nil hypotheses and estimating statistical power and planning sample size accordingly. We also offer information useful for understanding the relative importance of the effect sizes found in a particular study in relationship to others and which research domains have advanced more or less, given that larger effect sizes indicate a better understanding of a phenomenon. Also, our study offers information about research domains for which the investigation of moderating effects may be more fruitful and provide information that is likely to facilitate the implementation of Bayesian analysis. Finally, our study offers information that practitioners can use to evaluate the relative effectiveness of various types of interventions. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:25314367

Bosco, Frank A; Aguinis, Herman; Singh, Kulraj; Field, James G; Pierce, Charles A

2014-10-13

301

Image correlation and sampling study  

NASA Technical Reports Server (NTRS)

The development of analytical approaches for solving image correlation and image sampling of multispectral data is discussed. Relevant multispectral image statistics which are applicable to image correlation and sampling are identified. The general image statistics include intensity mean, variance, amplitude histogram, power spectral density function, and autocorrelation function. The translation problem associated with digital image registration and the analytical means for comparing commonly used correlation techniques are considered. General expressions for determining the reconstruction error for specific image sampling strategies are developed.

Popp, D. J.; Mccormack, D. S.; Sedwick, J. L.

1972-01-01

302

Correlation of neurocognitive function and brain parenchyma volumes in children surviving cancer  

NASA Astrophysics Data System (ADS)

This research builds on our hypothesis that white matter damage and associated neurocognitive symptoms, in children treated for cancer with cranial spinal irradiation, spans a continuum of severity that can be reliably probed using non-invasive MR technology. Quantitative volumetric assessments of MR imaging and psychological assessments were obtained in 40 long-term survivors of malignant brain tumors treated with cranial irradiation. Neurocognitive assessments included a test of intellect (Wechsler Intelligence Test for Children, Wechsler Adult Intelligence Scale), attention (Conner's Continuous Performance Test), and memory (California Verbal Learning Test). One-sample t-tests were conducted to evaluate test performance of survivors against age-adjusted scores from the test norms; these analyses revealed significant impairments in all apriori selected measures of intelligence, attention, and memory. Partial correlation analyses were performed to assess the relationships between brain tissues volumes (normal appearing white matter (NAWM), gray matter, and CSF) and neurocognitive function. Global intelligence (r = 0.32, p = 0.05) and global attentional (r = 0.49, p < 0.01) were significantly positively correlated with NAWM volumes, whereas global memory was significantly positively correlated with overall brain parenchyma (r = 0.38, p = 0.04). We conclude that quantitative assessment of MR examinations in survivors of childhood cancer treated with cranial irradiation reveal that loss of NAWM is associated with decreased intellectual and attentional deficits, whereas overall parenchyma loss, as reflected by increased CSF and decreased white matter, is associated with memory-related deficits.

Reddick, Wilburn E.; White, Holly A.; Glass, John O.; Mulhern, Raymond K.

2002-04-01

303

Lick Galaxy Correlation Function Revised  

E-print Network

We re-estimate the angular 2-point galaxy correlation function from the Lick galaxy catalogue. We argue that the large-scale gradients observed in the Lick catalogue are dominated by real clustering and therefore they should not be subtracted prior to the estimation of the 2-p correlation function. We find that if no such correction is introduced the galaxy correlations are perfectly consistent with the those found in the APM survey. Thus, the long standing discrepancy between the Lick and APM angular correlations is lifted.

M. Plionis; S. Borgani

1994-01-21

304

Producing and Detecting Correlated atoms  

E-print Network

We discuss experiments to produce and detect atom correlations in a degenerate or nearly degenerate gas of neutral atoms. First we treat the atomic analog of the celebrated Hanbury Brown Twiss experiment, in which atom correlations result simply from interference effects without any atom interactions.We have performed this experiment for both bosons and fermions. Next we show how atom interactions produce correlated atoms using the atomic analog of spontaneous four-wavemixing. Finally, we briefly mention experiments on a one dimensional gas on an atom chip in which correlation effects due to both interference and interactions have been observed.

Christoph I. Westbrook; Martijn Schellekens; Aurélien Perrin; Valentina Krachmalnicoff; Jose Carlos Viana Gomes; Jean-Baptiste Trebbia; Jérôme Estève; Hong Chang; Isabelle Bouchoule; Denis Boiron; Alain Aspect; Tom Jeltes; John McNamara; Wim Hogervorst; Wim Vassen

2006-09-04

305

Orthogonal subspaces for correlation masking  

NASA Technical Reports Server (NTRS)

A digital correlation mask that induces orthogonality among a prescribed set of reference imagery is described. In this particular implementation, the resulting correlation is undersampled and shift-variant, though if it is applied to optical correlators, those limitations are removed. A method of introducing orthogonality among the weights among the training set from which filter values are obtained is derived, so that the correlation value from a given filter is representative of the unique nature of the reference object as compared against the other objects in the training class.

Juday, Richard D.; Fisher, Timothy E.

1990-01-01

306

Correlation of Palatal Rugoscopy with Gender, Palatal Vault Height and ABO Blood Groups in Three Different Indian Populations  

PubMed Central

Background: Palatal rugae (PR) are asymmetrical irregular elevations, recorded during maxillary cast fabrication, that can be used for identification purpose if previous comparative sources are available. Aim: This study investigated uniqueness of PR patterns in relation to gender, palatal vault forms, and ABO blood groups in three (North-East [N-E], Northern and Western) populations of India. Subjects and Methods: The study was conducted on randomly selected 90 students, 30 from each sub population. Design - The palatal vault was recorded as Types I, II, and III. The maxillary casts were analyzed for each subject. The blood group of each subject was also recorded. Pearson's correlation coefficient tests were performed on cross-tabulations to evaluate significant relationship among different variables. Results: The PR number was more among females with an insignificant correlation among gender and mean rugae size on both sides. Types I and II hard palate vaults were seen associated with straight forwardly directed PR pattern, while Type III with curved forwardly directed PR. On the right side, straight rugae shape was most common type. On the left side, straight rugae shape was most common in Northern population while in N-E and Western populations curved rugae was the dominating type. A highly significant correlation was found between ABO blood groups and different PR patterns. Conclusions: PR possesses unique characteristics and can be used along with palatal vault forms as well as ABO blood groups for racial and individualistic soft tissue oral print in forensic cases. PMID:25328791

Verma, KG; Verma, P; Bansal, N; Basavaraju, S; Sachdeva, SK; Khosa, R

2014-01-01

307

Randomized controlled trial of desloratadine for persistent allergic rhinitis: correlations between symptom improvement and quality of life.  

PubMed

Allergic rhinitis (AR) symptoms can impart emotional, quality of life (QOL), and work productivity burdens, especially in persistent AR (PER). Desloratadine, an H1-receptor antagonist, has been shown to be effective against nasal and nonnasal AR symptoms and to improve QOL. Exploratory analyses were conducted to evaluate whether desloratadine-mediated symptom improvement correlated with improvements in QOL and productivity. The Aerius Control: Clinical and Evaluative Profile of Treatment 2 (NCT00405964) study was a 12-week, multinational, randomized, placebo-controlled prospective study of once-daily desloratadine at 5 mg in subjects with moderate-to-severe PER. Assessments included twice-daily symptom severity ratings (0 = none to 3 = severe; total and individual symptoms), sleep interference (morning [A.M.]), interference with activities of daily living (ADL; evening [P.M.]), the Rhinoconjunctivitis Quality of Life Questionnaire-Standardized version (baseline and days 29 and 85), and the Work Productivity and Activity Impairment-Allergy-Specific questionnaire (baseline and weekly). Pearson product-moment correlation statistics (r) were determined to assess correlations between symptom score improvements and QOL factors. All desloratadine-treated patients (n = 360) were included in this exploratory analysis. In the desloratadine-treated patients, all correlations tested were positive (all p < 0.0001). The highest coefficients were seen for the correlations between A.M./P.M. PRIOR total five-symptom score and interference with ADL (r = 0.72) and between A.M. NOW congestion and ADL interference (r = 0.69). Continuous daily treatment of moderate-to-severe PER with desloratadine at 5 mg/day significantly improved symptoms, which correlated positively, albeit moderately, with QOL benefits and reversal of functional impairments caused by PER. PMID:23676577

Bousquet, Jean; Zuberbier, Torsten; Canonica, G Walter; Fokkens, Wytske J; Gopalan, Gokul; Shekar, Tulin

2013-01-01

308

Reference values, intertest correlations, and test-retest repeatability of selected tear film tests in healthy cats.  

PubMed

Objective-To determine reference values, intertest correlations, and test-retest repeatability of Schirmer tear test 1 (STT-1), phenol red thread test (PRTT), tear film breakup time (TFBUT), tear osmolarity, and meibometry in healthy cats. Design-Evaluation study. Animals-135 healthy domestic cats aged 0.5 to 12.8 years. Procedures-Each test was performed once in 120 cats and repeated in 40. Pearson correlation was used to assess correlation among tests. Intraclass correlation coefficients (ICCs) and 95% limits of agreement (LOA) were used to evaluate test-retest repeatability. Results-Median (95% central range) values were 18 mm/min (9 to 34 mm/min) for STT-1, 29 mm/15 s (15 to 37 mm/15 s) for PRTT, 12.4 seconds (9.1 to 17.7 seconds) for TFBUT, 322 mOsm/L (297 to 364 mOsm/L) for osmolarity, and 32 meibometry units (MU; 11 to 114 MU) for peak meibometry value. The STT-1 and PRTT values were positively correlated. Age was weakly associated with TFBUT and osmolarity. Meibometry measurements were higher for strips that contacted the tear film (285 MU) than for those that touched the eyelid margin only (32 MU). All ICCs were < 0.75, and 95% LOA were wide. Conclusions and Clinical Relevance-Tear deficiency should be suspected in cats with STT-1 < 9 mm/min, PRTT < 15 mm/15 s, or TFBUT < 9 to 10 seconds. Generally poor correlation among tests suggested that thorough tear film analysis requires performance of multiple tests in concert. Relatively poor test-retest repeatability should be considered when repeated tests are used to monitor tear film dysfunction and response to treatment. PMID:25632817

Sebbag, Lionel; Kass, Philip H; Maggs, David J

2015-02-15

309

Correlates of alcohol use in adults with ADHD and comorbid alcohol use disorders: exploratory analysis of a placebo-controlled trial of atomoxetine  

PubMed Central

Background Attention-deficit/hyperactivity disorder (ADHD) and substance use disorder are often comorbid in adults. The effects of ADHD treatment on comorbid alcohol use disorder have not been extensively studied. Objective To assess correlates of ADHD and alcohol use outcomes in ADHD with comorbid alcohol use disorders, via a post-hoc exploratory subgroup analysis of a previously conducted, randomized, double-blind, placebo controlled study of recently abstinent adults. Methods Adults who had ADHD and alcohol use disorders and were abstinent for 4–30 days were randomized to daily atomoxetine 25–100 mg (mean final dose=89.9 mg) or placebo for 12 weeks. Changes in ADHD symptoms from baseline to endpoint were assessed using the ADHD Investigator Symptom Rating Scale (AISRS) total score, alcohol use by the timeline followback method, and alcohol cravings by the Obsessive Compulsive Drinking Scale. Results Of 147 subjects receiving atomoxetine (n=72) or placebo (n=75) in the primary study, 80 (54%) completed 12 weeks (n=32 atomoxetine; n=48 placebo). Improvements in ADHD symptoms on the AISRS correlated significantly with decreases in alcohol cravings (Pearson’s r=0.28; 95% confidence interval [CI]=0.11–0.43; p=0.002), and the correlation was most notable with atomoxetine (r=0.29; CI [0.04 – 0.51]; p=0.023) rather than with placebo (r=0.24; CI [0.00–0.46]; p=0.055). On-treatment drinking levels correlated with AISRS scores (r=0.12; CI [0.05 –0.19]; p=0.001). Relapse to alcohol abuse significantly correlated with worse ADHD symptoms on 15 of 18 items of the AISRS in the placebo group (p<0.05 for each). Conclusions No baseline predictor (other than degree of sobriety) of alcohol use or ADHD outcomes emerged. ADHD symptom improvements correlated significantly with reductions in alcohol cravings, and relapse to alcohol abuse correlated significantly with worsening of most ADHD symptoms in the placebo group, but not in the atomoxetine group. This post-hoc subgroup analysis is of a hypothesis-generating nature, and the generalizability of the findings may be limited by exclusion of adults with common ADHD comorbidities from the base study. Further, prospective clinical trials in larger and more heterogeneous patient populations are warranted to confirm or reject these preliminary associations. PMID:22029549

Wilens, Timothy E.; Adler, Lenard A.; Tanaka, Yoko; Xiao, Feng; D’Souza, Deborah N.; Gutkin, Stephen W.; Upadhyaya, Himanshu P.

2013-01-01

310

Psychophysical correlations, synchronicity and meaning.  

PubMed

The dual-aspect framework which Jung developed with Wolfgang Pauli implies that psychophysical phenomena are neither reducible to physical processes nor to conscious mental activity. Rather, they constitute a radically novel kind of phenomena, deriving from correlations between the physical and the mental. In synchronistic events, a particular subclass of psychophysical phenomena, these correlations are explicated as experienced meaning. PMID:24673273

Atmanspacher, Harald

2014-04-01

311

Correlation filters for orientation estimation  

NASA Technical Reports Server (NTRS)

An important task in many vision applications is that of rapidly estimating the orientation of an object with respect to some frame of reference. Because of their speed and parallel processing capabilities, optical correlators should prove valuable in this application. This paper considers two algorithms for object orientation estimation based on optical correlations and presents some initial simulation results.

Kumar, B. V. K. Vijaya; Lee, Andrew J.; Connelly, James M.

1988-01-01

312

Regularized Generalized Canonical Correlation Analysis  

ERIC Educational Resources Information Center

Regularized generalized canonical correlation analysis (RGCCA) is a generalization of regularized canonical correlation analysis to three or more sets of variables. It constitutes a general framework for many multi-block data analysis methods. It combines the power of multi-block data analysis methods (maximization of well identified criteria) and…

Tenenhaus, Arthur; Tenenhaus, Michel

2011-01-01

313

Correlation Weights in Multiple Regression  

ERIC Educational Resources Information Center

A general theory on the use of correlation weights in linear prediction has yet to be proposed. In this paper we take initial steps in developing such a theory by describing the conditions under which correlation weights perform well in population regression models. Using OLS weights as a comparison, we define cases in which the two weighting…

Waller, Niels G.; Jones, Jeff A.

2010-01-01

314

Personality Correlates of Polydrug Abuse.  

ERIC Educational Resources Information Center

Although the personality correlates of heroin addiction, LSD use, and marijuana smoking have been frequently investigated, relatively few data are available to describe the personality or lifestyle variables correlated with the pattern of polydrug abuse. In an attempt to gather such information, 17 polydrug users, selected from a group of 224…

Kilpatrick, Dean G.; And Others

315

The Greenbergian Word Order Correlations.  

ERIC Educational Resources Information Center

An empirical study of word order correlations, based on a sample of 625 languages, determined exactly what pairs of elements correlate in order with the verb and object. An alternative to the Head-Dependent Theory is presented: the Branching Direction Theory, based on consistent ordering of phrasal and nonphrasal elements. (85 references)…

Dryer, Matthew S.

1992-01-01

316

A GENERAL CANONICAL CORRELATION INDEX  

Microsoft Academic Search

BECAUSE A CANONICAL CORRELATION IS THE CORRELATION BETWEEN 2 LINEAR COMPOSITES, IT PRESENTS SOME INTERPRETIVE PROBLEMS. NO MEASURE OF THE REDUNDANCY IN 1 SET OF VARIABLES, GIVEN ANOTHER SET OF VARIABLES, HAS BEEN AVAILABLE. A NONSYMMETRIC INDEX OF REDUNDANCY IS PROPOSED WHICH REPRESENTS THE AMOUNT OF PREDICTED VARIANCE IN A SET OF VARIABLES.

DOUGLAS STEWART; WILLIAM LOVE

1968-01-01

317

The relationship between English language learning strategies and proficiency of pre-university students: A study case of UMS  

NASA Astrophysics Data System (ADS)

This paper seeks to investigate the relationship between language learning strategies and proficiency in English. Fifty-six pre-university students (22 males, 34 females) of University Malaysia Sabah participated in this study. Oxford's Strategy Inventory for Language Learning (SILL) self-report questionnaire was adopted to identify the students' language learning strategies, whereas their proficiencies were judged based on their Malaysian University English Test (MUET) Results. Pearson's correlation coefficient, Spearman's rank correlation coefficient and the t-test were utilized to make statistical interpretation about the relationship. The knowledge obtained from this study will be helpful for future studies on how to improve the quality of learning and proficiency in English.

Kiram, Johannah Jamalul; Sulaiman, Jumat; Swanto, Suyansah; Din, Wardatul Akmam

2014-07-01

318

Neural correlations, decisions and actions  

PubMed Central

4. Summary of recent advances Multielectrode recording experiments let us measure correlations between the activity of individual neurons and the neural circuits in which they are embedded. Recently, multielectrode studies have been emphasizing how correlated neuronal activity is linked with behavior. Decisions are fundamental to voluntary behavior. Here, we discuss computations necessary to turn a decision into an action and review progress in studying correlated neural activity in areas of the brain which link sensory and motor representations. The themes that emerge are that correlated patterns of activity in populations of neurons can be revealed by measurements of field potential fluctuations and that these measurements can relate the activity of individual neurons to the activity of populations of neurons distributed across different regions of the brain. Investigations into patterns of neuronal correlation are helping us to understand how decisions and other cognitive processes result from the interactions between different brain systems that are responsible for controlling and regulating our behavior. PMID:20359885

Pesaran, Bijan

2010-01-01

319

Correlated correlation functions in random-bond ferromagnets  

NASA Astrophysics Data System (ADS)

The two-dimensional random-bond Q-state Potts model is studied for Q near 2 via the perturbative renormalisation group to one loop. It is shown that weak disorder induces cross-correlations between the quenched-averages of moments of the two-point spin/spin and energy/energy correlation functions, which should be observable numerically in specific linear combinations of various quenched correlation functions. The random-bond Ising model in (2+ ?) dimensions is similarly treated. As a byproduct, a simple method for deriving the scaling dimensions of all moments of the local energy operator is presented.

Davis, Tom; Cardy, John

2000-03-01

320

Psychosocial and Sociocultural Correlates of Depressive Symptoms Among Diverse African American Women  

PubMed Central

African American women are faced with many challenges regarding their historical, cultural, and social structural position in the United States that may heighten their vulnerability for depression, one of the most prevalent disorders that can engender poor functionality. The purpose of this cross-sectional pilot study was to foster greater understanding about the occurrence and correlates of depressive symptoms among a diverse convenience sample of 63 African American women recruited from a comprehensive primary health care clinic (n = 23), a small private academic institution (n = 25), and an urban community setting (n = 15). Self-report data concerning selected psychological, sociocultural, and biological factors were collected. Descriptive statistics, Pearson product moment correlation, and analysis of variance were used to analyze data. Results indicated several similarities and differences among the 3 groups of women concerning levels of depressive symptoms and their correlates. Among the total sample, symptoms of depression were mild among 65% of the women. Depressive symptoms were significant and positively associated with negative and ruminative thinking (r = 0.79, p < .01), low self-esteem (r = 0.58, p < .01), stressful life events (r = 0.43, p < .05), low social support (r = 0.46, p < .01), depression stigma (r= 0.36, p < 01), and indication of chronic diseases (r = 0.34, p <.01). Depressive symptoms were significant and negatively associated with resiliency (r = ?0.48, p < .01) and spiritual well-being [r = ?.47, p < .01). This research adds to the empirical data concerning contributors to depressive symptoms for African American women. PMID:23560351

Holden, Kisha B.; Hall, Stephanie P.; Robinson, Maryam; Triplett, Sharra; Babalola, Dolapo; Plummer, Valens; Treadwell, Henrie; Bradford, L. DiAnne

2013-01-01

321

Rac1 is correlated with aggressiveness and a potential therapeutic target for gastric cancer.  

PubMed

Rac1 is a member of the Rho GTPase family. Rac1 activity is critical in regulating cytoskeleton organization and thus, modulates a diverse spectrum of cellular functions in normal and malignant cells. The aims of the present study were to investigate the expression pattern and clinical significance of Rac1, as well as the role of Rac1 in gastric cancer tumorigenesis and metastasis. The expression of Rac1 in human gastric cancer was explored by immunohistochemistry. The correlation of Rac1 expression with the clinicopathological characteristics and the survival of patients were analyzed by Pearson's Chi-square and Kaplan-Meier analyses, respectively. Rac1 overexpression cell model was used to examine in vitro and in vivo effects of Rac1 in cell growth, migration and invasion. Rac1 was highly expressed in gastric cancer tissues and correlated with differentiation, local invasion, lymph node metastasis and Lauren's classification. Rac1 expression in gastric cancer predicted shorter survival. Overexpression of Rac1 in gastric cancer cells dramatically induced Rac1 activation and rendered a more aggressive phenotype such as increased cell growth and migration/invasion in vitro and in vivo. Inhibiting Rac1 activity by specific inhibitor abrogated the effects of Rac1 on the malignant phenotype. Our clinical findings demonstrated that Rac1 was well correlated with aggressiveness and a negative prognostic factor. In addition, our data on experimental cell models supported the fundamental role of Rac1 in gastric cancer. Given its pivotal role in gastric tumorigenesis and progression, Rac1 can serve as a promising therapeutic target for gastric cancer. PMID:25585795

Ji, Jun; Feng, Xiaojing; Shi, Min; Cai, Qu; Yu, Yingyan; Zhu, Zhenggang; Zhang, Jun

2015-03-01

322

Correlation between vertical misfits and stresses over implants from castable frameworks made of different alloys.  

PubMed

This study aims to investigate a possible correlation between vertical misfits and the stresses transmitted to implants from one-piece casted frameworks fabricated with 3 different materials: commercially pure titanium, cobalt chromium alloy, and nickel chromium titanium alloy. Twelve frameworks simulating screw-retained prosthesis were fabricated from a master cast with 5 implants. Each framework was screwed (20 Ncm) over a metal cast and the vertical mesial and distal misfits were measured using an optical microscope. The stresses transmitted to the implants were measured in a third model by a quantitative photoelastic analysis. Stress and vertical misfit data were statistically analyzed by ANOVA and least significant difference tests and the correlation tests were performed using Pearson Correlation Test (? = 0.05). Mean and standard deviation values of vertical misfit and stress over implants are presented, respectively: commercially pure titanium (29.09 ± 13.24 ?m and 11.38 ± 9.23 kPa), cobalt chromium alloy (27.05 ± 10.30 ?m and 15.83 ± 9.30 kPa), nickel chromium titanium alloy (24.95 ± 11.14 ?m and 16.39 ± 9.51 kPa). There were no significant differences for vertical misfit (P = 0.285). Regarding the stress analysis, there were significant differences between commercially pure titanium, cobalt chromium alloy, and nickel chromium titanium alloy (P = 0.035), with the lowest values for the commercially pure titanium. It may be concluded that stress over implants was affected by different procedures and materials for framework production. PMID:25329843

Barbosa, Gustavo Augusto Seabra; Bernardes, Sérgio Rocha; de França, Danilo Gonzaga Bernardo; das Neves, Flávio Domingues; de Mattos, Maria da Glória Chiarello; Ribeiro, Ricardo Faria

2014-11-01

323

A Correlational Study of Scoliosis and Trunk Balance in Adult Patients with Mandibular Deviation  

PubMed Central

Previous studies have confirmed that patients with mandibular deviation often have abnormal morphology of their cervical vertebrae. However, the relationship between mandibular deviation, scoliosis, and trunk balance has not been studied. Currently, mandibular deviation is usually treated as a single pathology, which leads to poor clinical efficiency. We investigated the relationship of spine coronal morphology and trunk balance in adult patients with mandibular deviation, and compared the finding to those in healthy volunteers. 35 adult patients with skeletal mandibular deviation and 10 healthy volunteers underwent anterior X-ray films of the head and posteroanterior X-ray films of the spine. Landmarks and lines were drawn and measured on these films. The axis distance method was used to measure the degree of scoliosis and the balance angle method was used to measure trunk balance. The relationship of mandibular deviation, spine coronal morphology and trunk balance was evaluated with the Pearson correlation method. The spine coronal morphology of patients with mandibular deviation demonstrated an “S” type curve, while a straight line parallel with the gravity line was found in the control group (significant difference, p<0.01). The trunk balance of patients with mandibular deviation was disturbed (imbalance angle >1°), while the control group had a normal trunk balance (imbalance angle <1°). There was a significant difference between the two groups (p<0.01). The degree of scoliosis and shoulder imbalance correlated with the degree of mandibular deviation, and presented a linear trend. The direction of mandibular deviation was the same as that of the lateral bending of thoracolumbar vertebrae, which was opposite to the direction of lateral bending of cervical vertebrae. Our study shows the degree of mandibular deviation has a high correlation with the degree of scoliosis and trunk imbalance, all the three deformities should be clinically evaluated in the management of mandibular deviation. PMID:23555836

Yang, Yang; Wang, Na; Wang, Wenyong; Ding, Yin; Sun, Shiyao

2013-01-01

324

Morphometry of the suprascapular notch: correlation with scapular dimensions and clinical relevance  

PubMed Central

Background Better knowledge of the suprascapular notch anatomy may help to prevent and to assess more accurately suprascapular nerve entrapment syndrome. Our purposes were to verify the reliability of the existing data, to assess the differences between the two genders, to verify the correlation between the dimensions of the scapula and the suprascapular notch, and to investigate the relationship between the suprascapular notch and the postero-superior limit of the safe zone for the suprascapular nerve. Methods We examined 500 dried scapulae, measuring seven distances related to the scapular body and suprascapular notch; they were also catalogued according to gender, age and side. Suprascapular notch was classified in accordance with Rengachary’s method. For each class, we also took into consideration the width/depth ratio. Furthermore, Pearson's correlation was calculated. Results The frequencies were: Type I 12.4%, Type II 19.8%, Type III 22.8%, Type IV 31.1%, Type V 10.2%, Type VI 3.6%. Width and depth did not demonstrate a statistical significant difference when analyzed according to gender and side; however, a significant difference was found between the depth means elaborated according to median age (73 y.o.). Correlation indexes were weak or not statistically significant. The differences among the postero-superior limits of the safe zone in the six types of notches was not statistically significant. Conclusions Patient’s characteristics (gender, age and scapular dimensions) are not related to the characteristics of the suprascapular notch (dimensions and Type); our data suggest that the entrapment syndrome is more likely to be associated with a Type III notch because of its specific features. PMID:23705803

2013-01-01

325

Perception of better nasal patency correlates with increases in mucosal cooling after surgery for nasal obstruction  

PubMed Central

Objectives 1. Quantify mucosal cooling (i.e., heat loss) spatially in the nasal passages of nasal airway obstruction (NAO) patients before and after surgery using computational fluid dynamics (CFD). 2. Correlate mucosal cooling with patient-reported symptoms, as measured by the Nasal Obstruction Symptom Evaluation (NOSE) and a visual analog scale (VAS) for sensation of nasal airflow. Study Design Prospective Setting Academic tertiary medical center. Subjects and Methods Computed tomography (CT) scans and NOSE and VAS surveys were obtained from 10 patients before and after surgery to relieve NAO. Three-dimensional models of each patient’s nasal anatomy were used to run steady-state CFD simulations of airflow and heat transfer during inspiration. Heat loss across the nasal vestibule and the entire nasal cavity, and the surface area of mucosa exposed to heat fluxes > 50 W/m2 were compared pre- and post-operatively. Results After surgery, heat loss increased significantly on the pre-operative most obstructed side (p values < 0.0002). A larger surface area of nasal mucosa was exposed to heat fluxes > 50 W/m2 after surgery. The best correlation between patient-reported and CFD measures of nasal patency was obtained for NOSE against surface area in which heat fluxes > 50 W/m2 (Pearson r = ?0.76). Conclusion A significant post-operative increase in mucosal cooling correlates well with patients’ perception of better nasal patency after NAO surgery. CFD-derived heat fluxes may prove to be a valuable predictor of success in NAO surgery. PMID:24154749

Sullivan, Corbin D.; Garcia, Guilherme J. M.; Frank, Dennis O.; Kimbell, Julia S.; Rhee, John S.

2014-01-01

326

Fatty acid correlates of temperament in adolescent boys with attention deficit hyperactivity disorder.  

PubMed

Atypical fatty acid metabolism has been reported in attention deficit hyperactivity disorder (ADHD), however, its relationship with temperament in this population is unclear. The current study investigated the association between blood levels of fatty acids implicated in brain structure and function (omega-3, omega-6, omega-9) and personality traits of stability (neuroticism, conscientiousness and agreeableness) and plasticity (extraversion and openness). Twenty right-handed adolescent boys with ADHD completed a self-report NEO-FFI personality questionnaire, and had fatty acid content assessed from red blood using gas chromatography. Pearson's correlations showed no significant associations between omega-3 levels and personality. After correction for multiple comparisons, Adrenic Acid (C22:4n6) was inversely associated with stability. Oleic acid (C18:1n9) was positively associated with plasticity. Results are in line with a role of fatty acids in brain function. They suggest that those fatty acids that are involved in myelination (Adrenic, Oleic) have the strongest associations with temperament in adolescents with ADHD. PMID:23566869

Sumich, Alex L; Matsudaira, Toshiko; Heasman, Bryony; Gow, Rachel V; Ibrahimovic, Almira; Ghebremeskel, Kebreab; Crawford, Michael A; Taylor, Eric

2013-06-01

327

Correlating information contents of gene ontology terms to infer semantic similarity of gene products.  

PubMed

Successful applications of the gene ontology to the inference of functional relationships between gene products in recent years have raised the need for computational methods to automatically calculate semantic similarity between gene products based on semantic similarity of gene ontology terms. Nevertheless, existing methods, though having been widely used in a variety of applications, may significantly overestimate semantic similarity between genes that are actually not functionally related, thereby yielding misleading results in applications. To overcome this limitation, we propose to represent a gene product as a vector that is composed of information contents of gene ontology terms annotated for the gene product, and we suggest calculating similarity between two gene products as the relatedness of their corresponding vectors using three measures: Pearson's correlation coefficient, cosine similarity, and the Jaccard index. We focus on the biological process domain of the gene ontology and annotations of yeast proteins to study the effectiveness of the proposed measures. Results show that semantic similarity scores calculated using the proposed measures are more consistent with known biological knowledge than those derived using a list of existing methods, suggesting the effectiveness of our method in characterizing functional relationships between gene products. PMID:24963342

Gan, Mingxin

2014-01-01

328

Correlating Information Contents of Gene Ontology Terms to Infer Semantic Similarity of Gene Products  

PubMed Central

Successful applications of the gene ontology to the inference of functional relationships between gene products in recent years have raised the need for computational methods to automatically calculate semantic similarity between gene products based on semantic similarity of gene ontology terms. Nevertheless, existing methods, though having been widely used in a variety of applications, may significantly overestimate semantic similarity between genes that are actually not functionally related, thereby yielding misleading results in applications. To overcome this limitation, we propose to represent a gene product as a vector that is composed of information contents of gene ontology terms annotated for the gene product, and we suggest calculating similarity between two gene products as the relatedness of their corresponding vectors using three measures: Pearson's correlation coefficient, cosine similarity, and the Jaccard index. We focus on the biological process domain of the gene ontology and annotations of yeast proteins to study the effectiveness of the proposed measures. Results show that semantic similarity scores calculated using the proposed measures are more consistent with known biological knowledge than those derived using a list of existing methods, suggesting the effectiveness of our method in characterizing functional relationships between gene products. PMID:24963342

2014-01-01

329

The Interpretation of Correlation Data.  

E-print Network

= .844 f .013 Line 654, r =.416 f.055 Line 223, r =.307 f .061 Kafir Lines 654 and 223. Number Nodes per Head. 3 4 5 6'7. 8 9 There is a strong positive correlation here between the number of nodes per head and the number of seed branches. If one... that increases the correlation- to more than double the normal effect that one might expect of non-genetic corre- lations. Hence, one might conclude with certainty that there does exist a genetic correlation between number of nodes per head and number of seed...

Conner, A. B. (Arthur Benjamin)

1923-01-01

330

Pion correlations in Nuclear Matter  

E-print Network

The saturation properties of the nuclear matter taking pion correlations into account is studied. We construct a Bogoliubov transformations for the pion pair operators and calculate the energy associated with the pion pairs. The pion dispersion relation is investigated. We next study the correlation energy due to one pion exchange in nuclear matter and neutron matter at random phase approximation using the generator coordinate method. The techniques of the charged pion correlations are discussed in the neutron matter calculations. We observe that there is no sign of the pion condensation in this model.

P. K. Panda; S. Sarangi; J. da Providência

2009-10-17

331

Pseudopotentials for correlated electron systems  

NASA Astrophysics Data System (ADS)

A scheme is developed for creating pseudopotentials for use in correlated-electron calculations. Pseudopotentials for the light elements H, Li, Be, B, C, N, O, and F, are reported, based on data from high-level quantum chemical calculations. Results obtained with these correlated electron pseudopotentials (CEPPs) are compared with data for atomic energy levels and the dissociation energies, molecular geometries, and zero-point vibrational energies of small molecules obtained from coupled cluster single double triple calculations with large basis sets. The CEPPs give better results in correlated-electron calculations than Hartree-Fock-based pseudopotentials available in the literature.

Trail, J. R.; Needs, R. J.

2013-07-01

332

Does the intensity of diffuse thyroid gland uptake on F-18 fluorodeoxyglucose positron emission tomography/computed tomography scan predict the severity of hypothyroidism? Correlation between maximal standardized uptake value and serum thyroid stimulating hormone levels  

PubMed Central

Context: F-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) scan and hypothyroidism. Aims: The aim was to determine whether the intensity of diffuse thyroid gland uptake on F-18 FDG PET/CT scans predicts the severity of hypothyroidism. Materials and Methods: A retrospective analysis of 3868 patients who underwent F-18 FDG PET/CT scans, between October 2012 and June 2013 in our institution for various oncological indications was done. Out of them, 106 (2.7%) patients (79 females, 27 males) presented with bilateral diffuse thyroid gland uptake as an incidental finding. These patients were investigated retrospectively and various parameters such as age, sex, primary cancer site, maximal standardized uptake value (SUVmax), results of thyroid function tests (TFTs) and fine-needle aspiration cytology results were noted. The SUVmax values were correlated with serum thyroid stimulating hormone (S. TSH) levels using Pearson's correlation analysis. Statistical Analysis Used: Pearson's correlation analysis. Results: Clinical information and TFT (serum FT3, FT4 and TSH levels) results were available for 31 of the 106 patients (27 females, 4 males; mean age 51.5 years). Twenty-six out of 31 patients (84%) were having abnormal TFTs with abnormal TSH levels in 24/31 patients (mean S. TSH: 22.35 ?IU/ml, median: 7.37 ?IU/ml, range: 0.074-211 ?IU/ml). Among 7 patients with normal TSH levels, 2 patients demonstrated low FT3 and FT4 levels. No significant correlation was found between maximum standardized uptake value and TSH levels (r = 0.115, P > 0.05). Conclusions: Incidentally detected diffuse thyroid gland uptake on F-18 FDG PET/CT scan was usually associated with hypothyroidism probably caused by autoimmune thyroiditis. Patients should be investigated promptly irrespective of the intensity of FDG uptake with TFTs to initiate replacement therapy and a USG examination to look for any suspicious nodules. PMID:25589800

Pruthi, Ankur; Choudhury, Partha Sarathi; Gupta, Manoj; Taywade, Sameer

2015-01-01

333

Optimising parallel R correlation matrix calculations on gene expression data using MapReduce.  

PubMed

BackgroundHigh-throughput molecular profiling data has been used to improve clinical decision making by stratifying subjects based on their molecular profiles. Unsupervised clustering algorithms can be used for stratification purposes. However, the current speed of the clustering algorithms cannot meet the requirement of large-scale molecular data due to poor performance of the correlation matrix calculation. With high-throughput sequencing technologies promising to produce even larger datasets per subject, we expect the performance of the state-of-the-art statistical algorithms to be further impacted unless efforts towards optimisation are carried out. MapReduce is a widely used high performance parallel framework that can solve the problem.ResultsIn this paper, we evaluate the current parallel modes for correlation calculation methods and introduce an efficient data distribution and parallel calculation algorithm based on MapReduce to optimise the correlation calculation. We studied the performance of our algorithm using two gene expression benchmarks. In the micro-benchmark, our implementation using MapReduce, based on the R package RHIPE, demonstrates a 3.26-5.83 fold increase compared to the default Snowfall and 1.56-1.64 fold increase compared to the basic RHIPE in the Euclidean, Pearson and Spearman correlations. Though vanilla R and the optimised Snowfall outperforms our optimised RHIPE in the micro-benchmark, they do not scale well with the macro-benchmark. In the macro-benchmark the optimised RHIPE performs 2.03-16.56 times faster than vanilla R. Benefiting from the 3.30-5.13 times faster data preparation, the optimised RHIPE performs 1.22-1.71 times faster than the optimised Snowfall. Both the optimised RHIPE and the optimised Snowfall successfully performs the Kendall correlation with TCGA dataset within 7 hours. Both of them conduct more than 30 times faster than the estimated vanilla R.ConclusionsThe performance evaluation found that the new MapReduce algorithm and its implementation in RHIPE outperforms vanilla R and the conventional parallel algorithms implemented in R Snowfall. We propose that MapReduce framework holds great promise for large molecular data analysis, in particular for high-dimensional genomic data such as that demonstrated in the performance evaluation described in this paper. We aim to use this new algorithm as a basis for optimising high-throughput molecular data correlation calculation for Big Data. PMID:25371114

Wang, Shicai; Pandis, Ioannis; Johnson, David; Emam, Ibrahim; Guitton, Florian; Oehmichen, Axel; Guo, Yike

2014-11-01

334

Pooling and Correlated Neural Activity  

PubMed Central

Correlations between spike trains can strongly modulate neuronal activity and affect the ability of neurons to encode information. Neurons integrate inputs from thousands of afferents. Similarly, a number of experimental techniques are designed to record pooled cell activity. We review and generalize a number of previous results that show how correlations between cells in a population can be amplified and distorted in signals that reflect their collective activity. The structure of the underlying neuronal response can significantly impact correlations between such pooled signals. Therefore care needs to be taken when interpreting pooled recordings, or modeling networks of cells that receive inputs from large presynaptic populations. We also show that the frequently observed runaway synchrony in feedforward chains is primarily due to the pooling of correlated inputs. PMID:20485451

Rosenbaum, Robert J.; Trousdale, James; Josi?, Krešimir

2009-01-01

335

Jet correlations - opportunities and pitfalls  

E-print Network

The simplest observables used to probe the interaction of hard partons with a QCD medium in ultrarelativistic heavy ion collisions measure disappearance, such as the nuclear modification factor R_AA. The information content of such observables is however limited. More differential information is obtained from triggered correlation observables where a trigger condition ensures that a hard event has taken place and the correlation of other objects in the event with the trigger contains information about the nature of parton-medium interaction. By construction, triggered correlation observables are conditional probabilities, i.e. they measure events biased by the trigger condition. The presence of this bias makes the interpretation of observables non-intuitive, but at the same time represents an opportunity to design future measurements to selectively probe particular physics. In this work, an overview over the four types of biases occuring in triggered hard correlation observables is given, followed by a study ...

Renk, Thorsten

2014-01-01

336

Acoustic Correlates of Information Structure.  

E-print Network

This paper reports three studies aimed at addressing three questions about the acoustic correlates of information structure in English: (1) do speakers mark information structure prosodically, and, to the extent they do; ...

Breen, Mara

337

Illusory correlations in graphological inference.  

PubMed

The authors investigate the illusory correlation phenomenon as a possible contributor to the persistence of graphology's use to predict personality. Participants unfamiliar with graphology inspected handwriting samples paired with fabricated personality profiles. In Experiment 1, handwriting samples and personality profiles were randomly paired. In Experiment 2, discernible correlations near unity were set between targeted handwriting-feature-personality-trait pairs in a congruent or incongruent direction with graphologists' claims. In both experiments, participants' judgments of the correlation between designated handwriting-feature-personality-trait pairs agreed with graphologists' claims, even after controlling for their actual statistical association. Semantic association between words used to describe handwriting features and personality traits was the source of biases in perceived correlation. Results may partially account for continued use of graphology despite overwhelming evidence against its predictive validity. PMID:11218342

King, R N; Koehler, D J

2000-12-01

338

Correlated nucleons in configuration space  

SciTech Connect

Several recent studies have dealt with the effects of short-range correlations on the momentum distribution of nucleons in nuclei. Here we investigate the correlation effects on the density and spectral distribution in coordinate space. A combination of experimental data and spectral functions calculated from realistic nucleon-nucleon interactions allows us to resolve a recently uncovered discrepancy with occupation of quasiparticle states derived from (e,e{sup '}p) data.

Muether, Herbert; Sick, Ingo [Institut fuer Theoretische Physik, Universitaet Tuebingen, Tuebingen (Germany); Department fuer Physik und Astronomie, Universitaet Basel, Basel (Switzerland)

2004-10-01

339

Magnetic correlations and neutron scattering  

Microsoft Academic Search

An introduction is given to the methods and results of some recent researches into statistical thermodynamics bearing upon the correlation functions of magnetic moments in Heisenberg-coupled spin-only magnets, and their intimate connection with neutron-scattering theory and practice is brought out. The interrelationships between the correlation function, the relaxation function, the generalized susceptibility, the power spectrum of the fluctuations and the

W. Marshall; R. D. Lowde

1968-01-01

340

Correlated imaging through atmospheric turbulence  

SciTech Connect

Correlated imaging through atmospheric turbulence is studied, and the analytical expressions describing turbulence effects on image resolution are derived. Compared with direct imaging, correlated imaging can reduce the influence of turbulence to a certain extent and reconstruct high-resolution images. The result is backed up by numerical simulations, in which turbulence-induced phase perturbations are simulated by random-phase screens inserted into propagation paths.

Zhang Pengli; Gong Wenlin; Shen Xia; Han Shensheng [Key Laboratory for Quantum Optics and Center for Cold Atom Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

2010-09-15

341

Correlated imaging through atmospheric turbulence  

Microsoft Academic Search

Correlated imaging through atmospheric turbulence is studied, and the analytical expressions describing turbulence effects on image resolution are derived. Compared with direct imaging, correlated imaging can reduce the influence of turbulence to a certain extent and reconstruct high-resolution images. The result is backed up by numerical simulations, in which turbulence-induced phase perturbations are simulated by random-phase screens inserted into propagation

Pengli Zhang; Wenlin Gong; Xia Shen; Shensheng Han

2010-01-01

342

Correlated imaging through atmospheric turbulence  

E-print Network

Correlated imaging through atmospheric turbulence is studied, and the analytical expressions describing turbulence effects on image resolution are derived. Compared with direct imaging, correlated imaging can reduce the influence of turbulence to a certain extent and reconstruct high-resolution images. The result is backed up by numerical simulations, in which turbulence-induced phase perturbations are simulated by random phase screens inserting propagation paths.

Pengli Zhang; Wenlin Gong; Xia Shen; Shensheng Han

2010-05-27

343

Quantum correlations in semiconductor microcavities  

NASA Astrophysics Data System (ADS)

The quantum mechanical nature of the light field in semiconductor microcavities leads to non-classical coupling effects between photons and electron-hole excitations. It is shown that these quantum correlations give rise to characteristic corrections of the semiclassical light-matter coupling dynamics. Examples of quantum correlation signatures include entanglement effects in the probe reflection of a microcavity system and squeezing in the incoherent emission.

Kira, M.; Hoyer, W.; Koch, S. W.; Brick, P.; Ell, C.; Hübner, M.; Khitrova, G.; Gibbs, H. M.

2003-10-01

344

Computable measure of quantum correlation  

NASA Astrophysics Data System (ADS)

A general state of an system is a classical-quantum state if and only if its associated -correlation matrix (a matrix constructed from the coherence vector of the party , the correlation matrix of the state, and a function of the local coherence vector of the subsystem ), has rank no larger than . Using the general Schatten -norms, we quantify quantum correlation by measuring any violation of this condition. The required minimization can be carried out for the general -norms and any function of the local coherence vector of the unmeasured subsystem, leading to a class of computable quantities which can be used to capture the quantumness of correlations due to the subsystem . We introduce two special members of these quantifiers: The first one coincides with the tight lower bound on the geometric measure of discord, so that such lower bound fully captures the quantum correlation of a bipartite system. Accordingly, a vanishing tight lower bound on the geometric discord is a necessary and sufficient condition for a state to be zero-discord. The second quantifier has the property that it is invariant under a local and reversible operation performed on the unmeasured subsystem, so that it can be regarded as a computable well-defined measure of the quantum correlations. The approach presented in this paper provides a way to circumvent the problem with the geometric discord. We provide some examples to exemplify this measure.

Akhtarshenas, S. Javad; Mohammadi, Hamidreza; Karimi, Saman; Azmi, Zahra

2015-01-01

345

Analysis of Correlations between the Level of Partnering Relations and their Influence on the Time, Cost, Quality and Safety of Implementation of Construction Projects  

NASA Astrophysics Data System (ADS)

The present paper uses the developed model of the influence of partnering relations on the time, cost, quality and safety of implementation of construction projects. On its basis, a questionnaire has been created and a preliminary survey has been conducted. The paper presents an analysis of correlations between the level of partnering relations in the context of the partnering measures indicated in the model and their influence on the time, cost, quality and safety of implementation of construction projects. The analysis was conducted based on the data collected in 52 construction projects. The values of the Spearman rank correlation coefficient and the Pearson product-moment correlation coefficient have been calculated for the examined relations. The analysis allowed for indicating the measures of partnering whose improvement most often brings benefits with regard to the time, cost, quality and safety of implementation of construction projects. Among the 80 analysed correlations, the ones identified as strong were: 15 relations connected with the time, 8 with the cost, 5 with the quality and 1 with the safety of implementation of construction projects.

Radziszewska-Zielina, El?bieta; Szewczyk, Bart?omiej

2014-11-01

346

mirCoX: a database of miRNA-mRNA expression correlations derived from RNA-seq meta-analysis  

PubMed Central

Background Experimentally validated co-expression correlations between miRNAs and genes are a valuable resource to corroborate observations about miRNA/mRNA changes after experimental perturbations, as well as compare miRNA target predictions with empirical observations. For example, when a given miRNA is transcribed, true targets of that miRNA should tend to have lower expression levels relative to when the miRNA is not expressed. Methods We processed publicly available human RNA-seq experiments obtained from NCBI's Sequence Read Archive (SRA) to identify miRNA-mRNA co-expression trends and summarized them in terms of their Pearson's Correlation Coefficient (PCC) and significance. Results We found that sequence-derived parameters from TargetScan and miRanda were predictive of co-expression, and that TargetScan- and miRanda-derived gene-miRNA pairs tend to have anti-correlated expression patterns in RNA-seq data compared to controls. We provide this data for download and as a web application available at http://wrenlab.org/mirCoX/. Conclusion This database of empirically established miRNA-mRNA transcriptional correlations will help to corroborate experimental observations and could be used to help refine and validate miRNA target predictions. PMID:24267917

2013-01-01

347

Computer-Aided Quantification of Interstitial Lung Disease from High Resolution Computed Tomography Images in Systemic Sclerosis: Correlation with Visual Reader-Based Score and Physiologic Tests  

PubMed Central

Objective. To evaluate the performance of a computerized-aided method (CaM) for quantification of interstitial lung disease (ILD) in patients with systemic sclerosis and to determine its correlation with the conventional visual reader-based score (CoVR) and the pulmonary function tests (PFTs). Methods. Seventy-nine patients were enrolled. All patients underwent chest high resolution computed tomography (HRCT) scored by two radiologists adopting the CoVR. All HRCT images were then analysed by a CaM using a DICOM software. The relationships among the lung segmentation analysis, the readers, and the PFTs results were calculated using linear regression analysis and Pearson's correlation. Receiver operating curve analysis was performed for determination of CaM extent threshold. Results. A strong correlation between CaM and CoVR was observed (P < 0.0001). The CaM showed a significant negative correlation with forced vital capacity (FVC) (P < 0.0001) and the single breath carbon monoxide diffusing capacity of the lung (DLco) (P < 0.0001). A CaM optimal extent threshold of 20% represented the best compromise between sensitivity (75.6%) and specificity (97.4%). Conclusions. CaM quantification of SSc-ILD can be useful in the assessment of extent of lung disease and may provide reliable tool in daily clinical practice and clinical trials. PMID:25629053

Salaffi, Fausto; Carotti, Marina; Bosello, Silvia; Bichisecchi, Elisabetta; Giuseppetti, Gianmarco; Ferraccioli, Gianfranco

2015-01-01

348

Correlation between histological grading and ploidy status in potentially malignant disorders of the oral mucosa: A flow cytometric analysis  

PubMed Central

Background: Histopathological grading of oral dysplastic lesions is the method of choice for evaluating malignant and potentially malignant disorders. Owing to inter- and intra-observer variability, determination of the DNA ploidy status of lesions may serve as an adjunct in the prediction of malignant transformation. Aim: To correlate histopathological grading and ploidy status in potentially malignant and malignant disorders of the oral mucosa. Settings and Design: A pilot study was done with 30 patients (10 patients with oral potentially malignant disorders predominantly leukoplakia, 10 patients with oral malignant lesions and 10 patients with normal mucosa). Materials and Methods: Incisional biopsy was done after isolating the biopsy site with 1% Toluidine blue staining. Two sections of the tissue were removed and sent for histopathological and Flow-cytometric analysis respectively. Histopathological diagnosis was obtained and compared with Flow-cytometric results which were graded as diploid and aneuploid. Further, the S – phase fraction, DNA index were also calculated to evaluate the severity of malignant transformation or malignancy. Statistical Analysis: The results were analyzed using Pearson Chi-Square Test. Results: There exists a significant correlation between histopathology and ploidy status in both potentially malignant and malignant group. (P = 0.002). Conclusion: The data from this study has shown that DNA Ploidy analysis can be used as a valuable tool in assessing the carcinomatous progression of potentially malignant and malignant lesions. PMID:24250073

Vijayavel, T; Aswath, N

2013-01-01

349

Anthropometric measures of adiposity as correlates of atherogenic index of plasma in non-obese sedentary Nigerian males  

PubMed Central

Background The increase in cardiovascular events has necessitated the identification of possible predictors that can help in predicting atherogenicity. Objective The study sought to identify the anthropometric measures of adiposity that are associated with atherogenic risk in sedentary, non-obese, young male adults. Methods A cross-sectional design was used to recruit a purposive sample of 414 sedentary males in a university campus. Anthropometric measures of adiposity, lipid parameters, and atherogenic index of plasma (AIP) were assessed. Pearson correlation and stepwise multiple regression were used to analyze the data collected. Alpha level was set at p<0.05. Results There was a high risk of cardiovascular events (AIP=0.36±0.04 SD) among the participants. A significant correlation (p=0.000) was obtained between each of the anthropometric measures (except conicity index) and AIP. Body mass index, body adiposity index, and percent body fat were significant predictors accounting for 38.9, 3.1, and 2.2% of the variance due to AIP. Conclusions Sedentary status among young males is associated with high atherogenic risk in the presence of normal lipid and anthropometric parameters. Both central and general measures of adiposity predict less than half of the atherogenic risk in sedentary young males. PMID:24702831

Ezeukwu, Antoninus O.; Agwubike, Elias O.

2014-01-01

350

Jet correlations - opportunities and pitfalls  

E-print Network

The simplest observables used to probe the interaction of hard partons with a QCD medium in ultrarelativistic heavy ion collisions measure disappearance, such as the nuclear modification factor R_AA. The information content of such observables is however limited. More differential information is obtained from triggered correlation observables where a trigger condition ensures that a hard event has taken place and the correlation of other objects in the event with the trigger contains information about the nature of parton-medium interaction. By construction, triggered correlation observables are conditional probabilities, i.e. they measure events biased by the trigger condition. The presence of this bias makes the interpretation of observables non-intuitive, but at the same time represents an opportunity to design future measurements to selectively probe particular physics. In this work, an overview over the four types of biases occuring in triggered hard correlation observables is given, followed by a study of current jet correlation phenomenology in the light of the preceding discussion.

Thorsten Renk

2014-04-03

351

Recirculating cross-correlation detector  

DOEpatents

A digital cross-correlation detector is provided in which two time-varying signals are correlated by repetitively comparing data samples stored in digital form to detect correlation between the two signals. The signals are sampled at a selected rate converted to digital form, and stored in separate locations in separate memories. When the memories are filled, the data samples from each memory are first fed word-by-word through a multiplier and summing circuit and each result is compared to the last in a peak memory circuit and if larger than the last is retained in the peak memory. Then the address line to leading signal memory is offset by one byte to affect one sample period delay of a known amount in that memory and the data in the two memories are then multiplied word-by-word once again and summed. If a new result is larger than a former sum, it is saved in the peak memory together with the time delay. The recirculating process continues with the address of the one memory being offset one additional byte each cycle until the address is shifted through the length of the memory. The correlation between the two signals is indicated by the peak signal stored in the peak memory together with the delay time at which the peak occurred. The circuit is faster and considerably less expensive than comparable accuracy correlation detectors.

Andrews, W.H. Jr.; Roberts, M.J.

1985-01-18

352

Neurocognitive correlates of white matter in children surviving cancer: a quantitative MR imaging study  

NASA Astrophysics Data System (ADS)

Due to the inherent risk of central nervous system (CNS) dissemination, children treated for either acute lymphoblastic leukemia (ALL) or malignant brain tumors (BT) receive aggressive CNS therapy. The primary objective of this study was to confirm a previously observed association between reduced volumes of normal-appearing white matter (NAWM) and intellectual and attentional deficits in survivors. A combined MR imaging set consisting of T1, T2, and PD images were collected for 221 children (110 BT; 112 ALL). MR imaging sets were segmented with a hybrid neural network algorithm and volumetric measurements were calculated for five slices centered on the basal ganglia. Summary measures of Overall Index, Omissions, d" (attentiveness), and beta (risk-taking) were derived from the computer-administered Conners" Continuous Performance Test (CPT). Age-corrected estimates of Full-Scale IQ (FSIQ) were also obtained. Pearson correlation analyses were performed between each neurocognitive measure and the volume of NAWM. The correlation between FSIQ and NAWM failed to reach statistical significance for the BT group but was highly significant for the more homogeneous ALL group. Larger Omission rates, decreased attentiveness and more risk taking were significantly associated with lower NAWM volumes in both groups of survivors. Long-term survivors are at increased risk for cognitive delays or deficits, which oftentimes impair future academic performance, employment, and quality of life. These long-term adverse effects of treatment appear to be due to a diminished ability to acquire new information and may be secondary to deficits in attention, which is thought to be supported by interhemispheric and intrahemispheric white matter tracts.

Reddick, Wilburn E.; Glass, John O.; Shan, Zuyao Y.; Wu, Shengjie; Helton, Susan; Mulhern, Raymond K.

2005-04-01

353

Quantitative Ultrashort Echo Time (UTE) MRI of Human Cortical Bone: Correlation with Porosity and Biomechanical Properties  

PubMed Central

In this study we describe the use of ultrashort echo time (UTE) magnetic resonance imaging (MRI) to evaluate short and long T2* components as well as the water content of cortical bone. Fourteen human cadaveric distal femur and proximal tibia were sectioned to produce 44 rectangular slabs of cortical bone for quantitative UTE MR imaging, micro computed tomography (?CT), and biomechanical testing. A two-dimensional (2D) UTE pulse sequence with a minimal nominal TE of 8 ?s was used together with bi-component analysis to quantify the bound and free water in cortical bone using a clinical 3T scanner. Total water concentration was measured using a 3D UTE sequence together with a reference water phantom. UTE MR measures of water content (total, free and bound), T2* (short and long), and short and long T2* fractions were compared to porosity assessed with ?CT, as well as elastic (modulus, yield stress and strain) and failure (ultimate stress, failure strain and energy) properties, using Pearson correlation. Porosity significantly correlated positively with total (R2=0.23; P<0.01) and free (R2=0.31; P<0.001) water content as well as long T2* fraction (R2=0.25; P<0.001), and negatively with short T2* fraction and short T2* (R2=0.24; P<0.01). Failure strain significantly correlated positively with short T2* (R2=0.29; P<0.001), ultimate stress significantly correlated negatively with total (R2=0.25; P<0.001) and bound (R2=0.22; P<0.01) water content, and failure energy significantly correlated positively with both short (R2=0.30; P<0.001) and long (R2=0.17; P<0.01) T2* values. These results suggest that UTE MR measures are sensitive to the structure and failure properties of human cortical bone, and may provide a novel way of evaluating cortical bone quality. PMID:22190232

Bae, Won C.; Chen, Peter C.; Chung, Christine B.; Masuda, Koichi; D’Lima, Darryl; Du, Jiang

2012-01-01

354

Lower urinary tract symptoms, erectile dysfunction, and their correlation in men aged 50 years and above: a cross-sectional survey in beijing, china.  

PubMed

Background The aim of this study was to investigate the correlation between incidence of lower urinary tract symptoms and erectile dysfunction in men aged ?50 years. Material and Methods A cross-sectional study was performed in 1644 men aged >50 years in Beijing. The International Index of Erectile Function (IIEF)-5 and International Prostate Symptom Score were recorded for each patient. Pearson's chi-square test and Spearman correlation coefficients were used to analyze the International Prostate Symptom Scores and lower urinary tract symptoms, and their correlations with erectile dysfunction. Results The incidence rates of erectile dysfunction among men with mild, moderate, and severe lower urinary tract symptoms were 85.7, 93.7, and 97.9%, respectively. Interestingly, the total IIEF-5 score significantly correlated with the total International Prostate Symptom Score (r=-0.335; P<0.01), obstructive symptoms (r=-0.276; P<0.01), and irritative symptoms (r=-0.326; P<0.01). The correlation between the severity of lower urinary tract symptoms and that of erectile dysfunction was consistently maintained (r=0.304; P<0.01). Age significantly correlated with International Prostate Symptom Score (r=0.388; P<0.01), lower urinary tract symptoms severity (r=0.457; P<0.01), total IIEF-5 score (r=-0.533; P<0.01), and erectile dysfunction severity (r=0.529; P<0.01). Conclusions The incidence of lower urinary tract symptoms and erectile dysfunction in aging men increase with age, and the severity of erectile dysfunction is positively correlated with the severity of lower urinary tract symptoms. PMID:25543209

Song, Jian; Shao, Qiang; Tian, Ye; Chen, Shan

2014-01-01

355

Saving time and money: a validation of the self ratings on the prospective NIMH life-chart method (NIMH-LCM)  

PubMed Central

Background Careful observation of the longitudinal course of bipolar disorders is pivotal to finding optimal treatments and improving outcome. A useful tool is the daily prospective Life-Chart Method, developed by the National Institute of Mental Health. However, it remains unclear whether the patient version is as valid as the clinician version. Methods We compared the patient-rated version of the Lifechart (LC-self) with the Young-Mania-Rating Scale (YMRS), Inventory of Depressive Symptoms–Clinician version (IDS-C), and Clinical Global Impression–Bipolar version (CGI-BP) in 108 bipolar I and II patients who participated in the Naturalistic Follow-up Study (NFS) of the German centres of the Bipolar Collaborative Network (BCN; formerly Stanley Foundation Bipolar Network). For statistical evaluation, levels of severity of mood states on the Lifechart were transformed numerically and comparison with affective scales was performed using chi-square and t tests. For testing correlations Pearson´s coefficient was calculated. Results Ratings for depression of LC-self and total scores of IDS-C were found to be highly correlated (Pearson coefficient r?=??.718; p?correlation of ratings for mania with YMRS compared to LC-self were slightly less robust (Pearson coefficient r?=?.491; p?=?.001). These results were confirmed by good correlations between the CGI-BP IA (mania), IB (depression) and IC (overall mood state) and the LC-self ratings (Pearson coefficient r?=?.488, r?=?.721 and r?=?.65, respectively; all p?correlation and good concordance with standard cross sectional affective rating scales, suggesting that the LC-self is a valid and time and money saving alternative to the clinician-rated version which should be incorporated in future clinical research in bipolar disorder. Generalizability of the results is limited by the selection of highly motivated patients in specialized bipolar centres and by the open design of the study. PMID:24886463

2014-01-01

356

Correlated optical and isotopic nanoscopy  

NASA Astrophysics Data System (ADS)

The isotopic composition of different materials can be imaged by secondary ion mass spectrometry. In biology, this method is mainly used to study cellular metabolism and turnover, by pulsing the cells with marker molecules such as amino acids labelled with stable isotopes (15N, 13C). The incorporation of the markers is then imaged with a lateral resolution that can surpass 100?nm. However, secondary ion mass spectrometry cannot identify specific subcellular structures like organelles, and needs to be correlated with a second technique, such as fluorescence imaging. Here, we present a method based on stimulated emission depletion microscopy that provides correlated optical and isotopic nanoscopy (COIN) images. We use this approach to study the protein turnover in different organelles from cultured hippocampal neurons. Correlated optical and isotopic nanoscopy can be applied to a variety of biological samples, and should therefore enable the investigation of the isotopic composition of many organelles and subcellular structures.

Saka, Sinem K.; Vogts, Angela; Kröhnert, Katharina; Hillion, François; Rizzoli, Silvio O.; Wessels, Johannes T.

2014-04-01

357

Angular correlations of galaxy distribution  

E-print Network

We study the angular correlations of various galaxy catalogs (CfA1, SSRS1, Perseus-Pisces, APM Bright Galaxies and Zwicky). We find that the angular correlation exponent is $\\gamma_a= 0.1 \\pm 0.1$ rather than $\\gamma_a=0.7$ as usually found by the standard correlation function $\\omega(\\theta)$. We identify the problem in the artificial decay of $\\omega(\\theta)$. Moreover we find that no characteristic angular scale is present in any of the analyzed catalogs. Finally we show that all the available data are consistent with each other and the angular distribution of galaxies is quite naturally compatible with a fractal structure with $D \\approx 2$.

M. Montuori; F. Sylos-Labini

1997-06-30

358

Analysis of intraindividual and intraspecific variation in semicircular canal dimensions using high-resolution x-ray computed tomography  

PubMed Central

The semicircular canal system tracks head rotation and provides sensory input for the reflexive stabilization of gaze and posture. The purpose of this study was to investigate the intraspecific and intraindividual variation in the size of the three semicircular canals. The right and left temporal bones were extracted from 31 individuals of the short-tailed shrew (Blarina brevicauda) and scanned on a high-resolution x-ray computed tomography system. The radius of curvature was calculated for each of the three semicircular canals for each side. Paired t-tests and independent sample t-tests indicated no significant differences in canal size between the right and left canals of the same individuals or between those of males and females of the same species. Pearson product moment correlation analyses demonstrated that there was no significant correlation between canal size and body mass in this sample. PMID:19619167

Welker, Kelli L; Orkin, Joseph D; Ryan, Timothy M

2009-01-01

359

Analysis of intraindividual and intraspecific variation in semicircular canal dimensions using high-resolution x-ray computed tomography.  

PubMed

The semicircular canal system tracks head rotation and provides sensory input for the reflexive stabilization of gaze and posture. The purpose of this study was to investigate the intraspecific and intraindividual variation in the size of the three semicircular canals. The right and left temporal bones were extracted from 31 individuals of the short-tailed shrew (Blarina brevicauda) and scanned on a high-resolution x-ray computed tomography system. The radius of curvature was calculated for each of the three semicircular canals for each side. Paired t-tests and independent sample t-tests indicated no significant differences in canal size between the right and left canals of the same individuals or between those of males and females of the same species. Pearson product moment correlation analyses demonstrated that there was no significant correlation between canal size and body mass in this sample. PMID:19619167

Welker, Kelli L; Orkin, Joseph D; Ryan, Timothy M

2009-10-01

360

Supervised Multi-View Canonical Correlation Analysis (sMVCCA): Integrating Histologic and Proteomic Features for Predicting Recurrent Prostate Cancer.  

PubMed

In this work, we present a new methodology to facilitate prediction of recurrent prostate cancer (CaP) following radical prostatectomy (RP) via the integration of quantitative image features and protein expression in the excised prostate. Creating a fused predictor from high-dimensional data streams is challenging because the classifier must 1) account for the "curse of dimensionality" problem, which hinders classifier performance when the number of features exceeds the number of patient studies and 2) balance potential mismatches in the number of features across different channels to avoid classifier bias towards channels with more features. Our new data integration methodology, supervised Multi-view Canonical Correlation Analysis (sMVCCA), aims to integrate infinite views of highdimensional data to provide more amenable data representations for disease classification. Additionally, we demonstrate sMVCCA using Spearman's rank correlation which, unlike Pearson's correlation, can account for nonlinear correlations and outliers. Forty CaP patients with pathological Gleason scores 6-8 were considered for this study. 21 of these men revealed biochemical recurrence (BCR) following RP, while 19 did not. For each patient, 189 quantitative histomorphometric attributes and 650 protein expression levels were extracted from the primary tumor nodule. The fused histomorphometric/proteomic representation via sMVCCA combined with a random forest classifier predicted BCR with a mean AUC of 0.74 and a maximum AUC of 0.9286. We found sMVCCA to perform statistically significantly (p < 0.05) better than comparative state-of-the-art data fusion strategies for predicting BCR. Furthermore, Kaplan-Meier analysis demonstrated improved BCR-free survival prediction for the sMVCCA-fused classifier as compared to histology or proteomic features alone. PMID:25203987

Lee, George; Singanamalli, Asha; Wang, Haibo; Feldman, Michael D; Master, Stephen R; Shih, Natalie N C; Spangler, Elaine; Rebbeck, Timothy; Tomaszewski, John E; Madabhushi, Anant

2015-01-01

361

Correlation between Radiologic Sign of Lumbar Lordosis and Functional Status in Patients with Chronic Mechanical Low Back Pain  

PubMed Central

Study Design A cross-sectional study. Purpose To describe the correlation between lumbar lordosis angle and functional status of patients with chronic mechanical low back pain (CMLBP). Overview of Literature There are different and conflicting opinions regarding the relationship between the degree of lumbar lordosis and functional status of patients with low back pain. Nonetheless, the severity of lordosis is still one of the routine physical exams considered in rehabilitation clinics. Methods The degree of lumbar lordosis of 150 patients with CMLBP was measured by means of Cobb's method using sagittal standing spinal radiographs. Subjects with probable secondary causes of low back pain (trauma, congenital anomaly, spinal infection, rheumatologic problems and history of spinal surgery) were excluded. Besides recording demographic data, their score of functional disability was estimated using Oswestry Disability Questionnaire, one of the most useful and reliable questionnaires. Comparison between these data was made regarding different age and gender groups. Results In this study, 119 subjects were female and 31 male, with an age range of 19-85 years. The average degree of lumbar lordosis was 44.69±11.43 and that of Oswestry disability index (ODI) 30.52%. Although we found a significant direct relationship between age and degree of lumbar lordosis (Pearson's correlation coefficient, p=0.016, r=0.197), while insignificant correlation was seen between the degree of lumbar lordosis and ODI (p=0.129). Conclusions There was no significant correlation between the degree of lumbar lordosis and the score of functional disability with regards to different age groups and gender. PMID:25346808

Ashraf, Alireza; Farahangiz, Siamak; Pakniat Jahromi, Bita; Setayeshpour, Nazanin; Nasseri, Ali

2014-01-01

362

Minimum Bayes risk image correlation  

NASA Technical Reports Server (NTRS)

In this paper, the problem of designing a matched filter for image correlation will be treated as a statistical pattern recognition problem. It is shown that, by minimizing a suitable criterion, a matched filter can be estimated which approximates the optimum Bayes discriminant function in a least-squares sense. It is well known that the use of the Bayes discriminant function in target classification minimizes the Bayes risk, which in turn directly minimizes the probability of a false fix. A fast Fourier implementation of the minimum Bayes risk correlation procedure is described.

Minter, T. C., Jr.

1980-01-01

363

Correlation-based biological networks  

NASA Astrophysics Data System (ADS)

We construct a correlation-based biological network from a data set containing temporal expressions of 517 fibroblast tissue genes at transcription level. Four relevant and meaningful connected subgraphs of the network, namely: minimal spanning tree, maximal spanning tree, combined graph of minimal and maximal trees, and planar maximally filtered graph are extracted and the subgraphs' geometrical and topological properties are explored by computing relevant statistical quantities at local and global level. The results show that the subgraphs are extracting relevant information from the data set by retaining high correlation coeffcients. The design principle of the underlying biological functions is reflected in the topology of the graphs.

Song, Won-Min; Aste, Tomaso; Di Matteo, T.

2007-12-01

364

Petascale cross correlation in software  

NASA Astrophysics Data System (ADS)

The exascale computational demands of back-end processing in the era of the SKA and HERA, headlined by the needs of cross-correlation, are likely to require solutions that differ significantly from traditional approaches on smaller arrays. The rapid growth of massively-parallel general-purpose computing hardware presents an alternative to ASIC- or FPGA-based designs and promises several advantages. In this talk we present strong scaling results for an FX correlator that runs entirely in software on GPU-based off-the-shelf HPC clusters.

Barsdell, Benjamin R.; Clark, M. A.; Greenhill, L. J.

2014-04-01

365

Top Quark Spin Correlations - Theory  

SciTech Connect

The top quark decay width (G{sub F}m{sub t}{sup 3} {approx} 1 GeV) is much larger than the QCD hadronization scale ({Lambda}{sub QCD} {approx} 0.1 GeV) and much larger than the spin decorrelation scale ({Lambda}{sub QCD}{sup 2}/m{sub t} {approx} 0.1 MeV). Therefore, spin correlations in top quark pair production are reflected in angular correlations of the decay products, see [1] and [2].

Parke, Stephen J.; /Fermilab

2012-02-01

366

EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems  

NASA Astrophysics Data System (ADS)

Strongly correlated electrons is an exciting and diverse field in condensed matter physics. This special issue aims to capture some of that excitement and recent developments in the field. Given that this issue was inspired by the 2010 International Conference on Strongly Correlated Electron Systems (SCES 2010), we briefly give some history in order to place this issue in context. The 2010 International Conference on Strongly Correlated Electron Systems was held in Santa Fe, New Mexico, a reunion of sorts from the 1989 International Conference on the Physics of Highly Correlated Electron Systems that also convened in Santa Fe. SCES 2010—co-chaired by John Sarrao and Joe Thompson—followed the tradition of earlier conferences, in this century, hosted by Buzios (2008), Houston (2007), Vienna (2005), Karlsruhe (2004), Krakow (2002) and Ann Arbor (2001). Every three years since 1997, SCES has joined the International Conference on Magnetism (ICM), held in Recife (2000), Rome (2003), Kyoto (2006) and Karlsruhe (2009). Like its predecessors, SCES 2010 topics included strongly correlated f- and d-electron systems, heavy-fermion behaviors, quantum-phase transitions, non-Fermi liquid phenomena, unconventional superconductivity, and emergent states that arise from electronic correlations. Recent developments from studies of quantum magnetism and cold atoms complemented the traditional subjects and were included in SCES 2010. 2010 celebrated the 400th anniversary of Santa Fe as well as the birth of astronomy. So what's the connection to SCES? The Dutch invention of the first practical telescope and its use by Galileo in 1610 and subsequent years overturned dogma that the sun revolved about the earth. This revolutionary, and at the time heretical, conclusion required innovative combinations of new instrumentation, observation and mathematics. These same combinations are just as important 400 years later and are the foundation of scientific discoveries that were discussed during SCES 2010. As we learned, past dogmas about strongly correlated materials and phenomena must be re-examined with an open and inquisitive mind. Invited speakers and respected leaders in the field were invited to contribute to this special issue and we have insisted that they present new data, ideas, or perspectives, as opposed to simply an overview of their past work. As with the conference, this special issue touches upon recent developments of strongly correlated electron systems in d-electron materials, such as Sr3Ru2O7, graphene, and the new Fe-based superconductors, but it is dominated by topics in f-electron compounds. Contributions reflect the growing appreciation for the influence of disorder and frustration, the need for organizing principles, as well as detailed investigations on particular materials of interest and, of course, new materials. As this special issue could not possibly capture the full breadth and depth that the conference had to offer, it is being published simultaneously with an issue of Journal of Physics: Conference Series containing 157 manuscripts in which all poster presenters at SCES 2010 were invited to contribute. Since this special issue grew out of the 2010 SCES conference, we take this opportunity to give thanks. This conference would not have been possible without the hard work of the SCES 2010 Program Committee, International and National Advisory Committees, Local Committee, and conference organizers, the New Mexico Consortium. We thank them as well as those organizations that generously provided financial support: ICAM-I2CAM, Quantum Design, Lakeshore, the National High Magnetic Field Laboratory and the Department of Energy National Laboratories at Argonne, Berkeley, Brookhaven, Los Alamos and Oak Ridge. Of course, we especially thank the participants for bringing new ideas and new results, without which SCES 2010 would not have been possible. Strongly correlated electron systems contents Spin-orbit coupling and k-dependent Zeeman splitting in strontium ruthenate Emil J Rozbicki, James F Annett, Jean-René Souquet an

Ronning, Filip; Batista, Cristian

2011-03-01

367

PREFACE: Strongly correlated electron systems Strongly correlated electron systems  

NASA Astrophysics Data System (ADS)

This special section is dedicated to the Strongly Correlated Electron Systems Conference (SCES) 2011, which was held from 29 August-3 September 2011, in Cambridge, UK. SCES'2011 is dedicated to 100 years of superconductivity and covers a range of topics in the area of strongly correlated systems. The correlated electronic and magnetic materials featured include f-electron based heavy fermion intermetallics and d-electron based transition metal compounds. The selected papers derived from invited presentations seek to deepen our understanding of the rich physical phenomena that arise from correlation effects. The focus is on quantum phase transitions, non-Fermi liquid phenomena, quantum magnetism, unconventional superconductivity and metal-insulator transitions. Both experimental and theoretical work is presented. Based on fundamental advances in the understanding of electronic materials, much of 20th century materials physics was driven by miniaturisation and integration in the electronics industry to the current generation of nanometre scale devices. The achievements of this industry have brought unprecedented advances to society and well-being, and no doubt there is much further to go—note that this progress is founded on investments and studies in the fundamentals of condensed matter physics from more than 50 years ago. Nevertheless, the defining challenges for the 21st century will lie in the discovery in science, and deployment through engineering, of technologies that can deliver the scale needed to have an impact on the sustainability agenda. Thus the big developments in nanotechnology may lie not in the pursuit of yet smaller transistors, but in the design of new structures that can revolutionise the performance of solar cells, batteries, fuel cells, light-weight structural materials, refrigeration, water purification, etc. The science presented in the papers of this special section also highlights the underlying interest in energy-dense materials, which make use of 'small' electrons packed to the highest possible density. These are by definition 'strongly correlated'. For example: good photovoltaics must be efficient optical absorbers, which means that photons will generate tightly bound electron-hole pairs (excitons) that must then be ionised at a heterointerface and transported to contacts; efficient solid state refrigeration depends on substantial entropy changes in a unit cell, with large local electrical or magnetic moments; efficient lighting is in a real sense the inverse of photovoltaics; the limit of an efficient battery is a supercapacitor employing mixed valent ions; fuel cells and solar to fuel conversion require us to understand electrochemistry on the scale of a single atom; and we already know that the only prospect for effective high temperature superconductivity involves strongly correlated materials. Even novel IT technologies are now seen to have value not just for novel function but also for efficiency. While strongly correlated electron systems continue to excite researchers and the public alike due to the fundamental science issues involved, it seems increasingly likely that support for the science will be leveraged by its impact on energy and sustainability. Strongly correlated electron systems contents Strongly correlated electron systemsSiddharth S Saxena and P B Littlewood Magnetism, f-electron localization and superconductivity in 122-type heavy-fermion metalsF Steglich, J Arndt, O Stockert, S Friedemann, M Brando, C Klingner, C Krellner, C Geibel, S Wirth, S Kirchner and Q Si High energy pseudogap and its evolution with doping in Fe-based superconductors as revealed by optical spectroscopyN L Wang, W Z Hu, Z G Chen, R H Yuan, G Li, G F Chen and T Xiang Structural investigations on YbRh2Si2: from the atomic to the macroscopic length scaleS Wirth, S Ernst, R Cardoso-Gil, H Borrmann, S Seiro, C Krellner, C Geibel, S Kirchner, U Burkhardt, Y Grin and F Steglich Confinement of chiral magnetic modulations in the precursor region of FeGeH Wilhelm, M Baenitz, M Schmidt, C Naylor, R Lortz, U

Saxena, Siddharth S.; Littlewood, P. B.

2012-07-01

368

Correlation of phantom-based and log file patient-specific QA with complexity scores for VMAT.  

PubMed

The motivation for this study was to reduce physics workload relating to patient- specific quality assurance (QA). VMAT plan delivery accuracy was determined from analysis of pre- and on-treatment trajectory log files and phantom-based ionization chamber array measurements. The correlation in this combination of measurements for patient-specific QA was investigated. The relationship between delivery errors and plan complexity was investigated as a potential method to further reduce patient-specific QA workload. Thirty VMAT plans from three treatment sites - prostate only, prostate and pelvic node (PPN), and head and neck (H&N) - were retrospectively analyzed in this work. The 2D fluence delivery reconstructed from pretreatment and on-treatment trajectory log files was compared with the planned fluence using gamma analysis. Pretreatment dose delivery verification was also car- ried out using gamma analysis of ionization chamber array measurements compared with calculated doses. Pearson correlations were used to explore any relationship between trajectory log file (pretreatment and on-treatment) and ionization chamber array gamma results (pretreatment). Plan complexity was assessed using the MU/ arc and the modulation complexity score (MCS), with Pearson correlations used to examine any relationships between complexity metrics and plan delivery accu- racy. Trajectory log files were also used to further explore the accuracy of MLC and gantry positions. Pretreatment 1%/1 mm gamma passing rates for trajectory log file analysis were 99.1% (98.7%-99.2%), 99.3% (99.1%-99.5%), and 98.4% (97.3%-98.8%) (median (IQR)) for prostate, PPN, and H&N, respectively, and were significantly correlated to on-treatment trajectory log file gamma results (R = 0.989, p < 0.001). Pretreatment ionization chamber array (2%/2 mm) gamma results were also significantly correlated with on-treatment trajectory log file gamma results (R = 0.623, p < 0.001). Furthermore, all gamma results displayed a significant correlation with MCS (R > 0.57, p < 0.001), but not with MU/arc. Average MLC position and gantry angle errors were 0.001 ± 0.002 mm and 0.025° ± 0.008° over all treatment sites and were not found to affect delivery accuracy. However, vari- ability in MLC speed was found to be directly related to MLC position accuracy. The accuracy of VMAT plan delivery assessed using pretreatment trajectory log file fluence delivery and ionization chamber array measurements were strongly correlated with on-treatment trajectory log file fluence delivery. The strong corre- lation between trajectory log file and phantom-based gamma results demonstrates potential to reduce our current patient-specific QA. Additionally, insight into MLC and gantry position accuracy through trajectory log file analysis and the strong cor- relation between gamma analysis results and the MCS could also provide further methodologies to both optimize the VMAT planning and QA process.  PMID:25493524

Agnew, Christina E; Irvine, Denise M; McGarry, Conor K

2014-01-01

369

Sample Size and Correlational Inference  

ERIC Educational Resources Information Center

In 4 studies, the authors examined the hypothesis that the structure of the informational environment makes small samples more informative than large ones for drawing inferences about population correlations. The specific purpose of the studies was to test predictions arising from the signal detection simulations of R. B. Anderson, M. E. Doherty,…

Anderson, Richard B.; Doherty, Michael E.; Friedrich, Jeff C.

2008-01-01

370

Correlation effects and bound states  

SciTech Connect

Bound states in a simple quark model that are due to correlation effects are analyzed. The confining properties of this model in meson (quark-antiquark and diquark) channels manifest themselves at any quark momenta, and an extra potential field may only enhance the confining effect.

Zinovjev, G. M. [National Academy of Sciences of Ukraine, Bogolyubov Institute for Theoretical Physics (Ukraine); Molodtsov, S. V., E-mail: molodtsov@itep.ru [Joint Institute for Nuclear Research (Russian Federation)

2012-11-15

371

Multiparticle Bose-Einstein correlations  

NASA Astrophysics Data System (ADS)

Multiparticle symmetrization effects are contributions to the spectra of Bose-symmetrized states which are not the product of pairwise correlations. Usually they are neglected in particle interferometric calculations which aim at determining the geometry of the boson emitting source from the measured momentum distributions. Based on a method introduced by Zajc and Pratt, we give a calculation of all multiparticle symmetrization effects to the one- and two-particle momentum spectra for a Gaussian phase-space distribution of emission points. Our starting point is an ensemble of N-particle Bose-symmetrized wave functions with specified phase-space localization. In scenarios typical for relativistic heavy-ion collisions, multiparticle effects steepen the slope of the one-particle spectrum for realistic particle phase-space densities by up to 20 MeV, and they broaden the relative momentum dependence of the two-particle correlations. We discuss these modifications and their consequences in quantitative detail. Also, we explain how multiparticle effects modify the normalization of the two-particle correlator. The resulting normalization conserves event probabilities, which is not the case for the commonly used pair approximation. Finally, we propose a method of calculating Bose-Einstein weights from the output of event generators, taking multiparticle correlations into account.

Wiedemann, Urs Achim

1998-06-01

372

Acoustic correlates of information structure  

Microsoft Academic Search

This paper reports three studies aimed at addressing three questions about the acoustic correlates of information structure in English: (1) do speakers mark information structure prosodically, and, to the extent they do; (2) what are the acoustic features associated with different aspects of information structure; and (3) how well can listeners retrieve this information from the signal? The information structure

Mara Breen; Evelina Fedorenko; Michael Wagner; Edward Gibson

2010-01-01

373

Multilevel Modeling with Correlated Effects  

ERIC Educational Resources Information Center

When there exist omitted effects, measurement error, and/or simultaneity in multilevel models, explanatory variables may be correlated with random components, and standard estimation methods do not provide consistent estimates of model parameters. This paper introduces estimators that are consistent under such conditions. By employing generalized…

Kim, Jee-Seon; Frees, Edward W.

2007-01-01

374

Co-Overexpression of GEP100 and AMAP1 Proteins Correlates with Rapid Local Recurrence after Breast Conservative Therapy  

PubMed Central

A major problem of current cancer research and therapy is prediction of tumor recurrence after initial treatment, rather than the simple biological characterization of the malignancy and proliferative properties of tumors. Breast conservation therapy (BCT) is a well-approved, standard treatment for patients with early stages of breast cancer, which consists of lumpectomy and whole-breast irradiation. In spite of extensive studies, only 'age' and 'Ki-67 positivity' have been identified to be well correlated with local recurrence after BCT. An Arf6 pathway, activated by GEP100 under receptor tyrosine kinases (RTKs) and employs AMAP1 as its effector, is crucial for invasion and metastasis of some breast cancer cells. This pathway activates ?1 integrins and perturbs E-cadherin-based adhesions, hence appears to be integral for epithelial-mesenchymal transdifferentiation (EMT). We here show that expression of the Arf6 pathway components statistically correlates with rapid local recurrence after BCT. We retrospectively analyzed four hundred seventy-nine patients who received BCT in Hokkaido University Hospital, and found 20 patients had local recurrence. We then analyzed pathological samples of patients who experienced local recurrence by use of Kaplan-Meier analysis, Stepwise regression analysis and the t-test, coupled with immunostaining, and found that co-overexpression of GEP100 and AMAP1 correlates with rapidity of the local recurrence. Their margin-status, node-positivity, and estrogen receptor (ER)- or progesterone receptor (PgR)-positivity did not correlated with the rapidity. This study is the first to show that expression of a certain set of proteins correlates with the rapidity of local recurrence. Our results are useful not only for prediction, but highlight the possibility of developing novel strategies to block local recurrence. We also discuss why mRNAs encoding these proteins have not been identified to correlate with local recurrence by previous conventional gene expression profiling analyses. PMID:24116160

Kinoshita, Rumiko; Nam, Jin-Min; Ito, Yoichi M.; Hatanaka, Kanako C.; Hashimoto, Ari; Handa, Haruka; Otsuka, Yutaro; Hashimoto, Shigeru; Onodera, Yasuhito; Hosoda, Mitsuchika; Onodera, Shunsuke; Shimizu, Shinichi; Tanaka, Shinya; Shirato, Hiroki; Tanino, Mishie; Sabe, Hisataka

2013-01-01

375

Dynamics of electricity market correlations  

NASA Astrophysics Data System (ADS)

Electricity market participants rely on demand and price forecasts to decide their bidding strategies, allocate assets, negotiate bilateral contracts, hedge risks, and plan facility investments. However, forecasting is hampered by the non-linear and stochastic nature of price time series. Diverse modeling strategies, from neural networks to traditional transfer functions, have been explored. These approaches are based on the assumption that price series contain correlations that can be exploited for model-based prediction purposes. While many works have been devoted to the demand and price modeling, a limited number of reports on the nature and dynamics of electricity market correlations are available. This paper uses detrended fluctuation analysis to study correlations in the demand and price time series and takes the Australian market as a case study. The results show the existence of correlations in both demand and prices over three orders of magnitude in time ranging from hours to months. However, the Hurst exponent is not constant over time, and its time evolution was computed over a subsample moving window of 250 observations. The computations, also made for two Canadian markets, show that the correlations present important fluctuations over a seasonal one-year cycle. Interestingly, non-linearities (measured in terms of a multifractality index) and reduced price predictability are found for the June-July periods, while the converse behavior is displayed during the December-January period. In terms of forecasting models, our results suggest that non-linear recursive models should be considered for accurate day-ahead price estimation. On the other hand, linear models seem to suffice for demand forecasting purposes.

Alvarez-Ramirez, J.; Escarela-Perez, R.; Espinosa-Perez, G.; Urrea, R.

2009-06-01

376

Pulse-Wave Analysis of Optic Nerve Head Circulation Is Significantly Correlated with Kidney Function in Patients with and without Chronic Kidney Disease  

PubMed Central

Aim. To determine whether there is a significant correlation between the optic nerve head (ONH) circulation determined by laser speckle flowgraphy (LSFG) and kidney function. Materials. Seventy-one subjects were investigated. The estimated glomerular filtration rate (GFR) and serum creatinine, cystatin C, and urinary albumin excretion were measured. The ONH circulation was determined by an analysis of the pulse wave of LSFG, and this parameter was named blowout time (BOT). Chronic kidney disease (CKD) was defined to be present when the estimated GFR was <60?mL/min per 1.73?m2. Pearson's correlation coefficients were used to determine the relationship between the BOT and the kidney function. We also examined whether there were significant differences in all parameters in patients with and without CKD. Results. BOT was significantly correlated with the level of creatinine (r = ?0.24, P = 0.04), the estimated GFR (r = 0.42, P = 0.0003), cystatin C (r = ?0.29, P = 0.01), and urinary albumin excretion (r = ?0.29, P = 0.01). The BOT level in subjects with CKD was significantly lower than that in subjects without CKD (P = 0.002). Conclusion. BOT in ONH by LSFG can detect the organ damage such as kidney dysfunction, CKD. PMID:24678413

Takahashi, Mao

2014-01-01

377

Mast Cells Positive to Tryptase and c-Kit Receptor Expressing Cells Correlates with Angiogenesis in Gastric Cancer Patients Surgically Treated.  

PubMed

Background. Angiogenesis is a complex process involved in both growth and progression of several human and animal tumours. Tryptase is a serin protease stored in mast cells granules, which plays a role in tumour angiogenesis. Mast cells (MCs) can release tryptase following c-Kit receptor (c-KitR) activation. Method. In a series of 25 gastric cancer patients with stage T3N2-3M0 (by AJCC for Gastric Cancer 7th Edition), immunohistochemistry and image analysis methods were employed to evaluate in the tumour tissue the correlation between the number of mast cells positive to tryptase (MCPT), c-KitR expressing cells (c-KitR-EC), and microvascular density (MVD). Results. Data demonstrated a positive correlation between MCPT, c-KitR-EC, and MVD to each other. In tumour tissue the mean number of MCPT was 15, the mean number of c-KitR-EC was 20, and the mean number of MVD was 20. The Pearson test correlating MCPT and MVD, c-KitR-EC and MVD was significantly (r = 0.64, P = 0.001; r = 0.66, P = 0.041, resp.). Conclusion. In this pilot study, we suggest that MCPT and c-KitR-EC play a role in gastric cancer angiogenesis, so we think that several c-KitR or tryptase inhibitors such as gabexate mesilate and nafamostat mesilate might be evaluated in clinical trials as a new antiangiogenetic approach. PMID:24348541

Ammendola, Michele; Sacco, Rosario; Sammarco, Giuseppe; Donato, Giuseppe; Zuccalà, Valeria; Romano, Roberto; Luposella, Maria; Patruno, Rosa; Vallicelli, Carlo; Verdecchia, Giorgio Maria; Cavaliere, Davide; Montemurro, Severino; Ranieri, Girolamo

2013-01-01

378

Mast Cells Positive to Tryptase and c-Kit Receptor Expressing Cells Correlates with Angiogenesis in Gastric Cancer Patients Surgically Treated  

PubMed Central

Background. Angiogenesis is a complex process involved in both growth and progression of several human and animal tumours. Tryptase is a serin protease stored in mast cells granules, which plays a role in tumour angiogenesis. Mast cells (MCs) can release tryptase following c-Kit receptor (c-KitR) activation. Method. In a series of 25 gastric cancer patients with stage T3N2-3M0 (by AJCC for Gastric Cancer 7th Edition), immunohistochemistry and image analysis methods were employed to evaluate in the tumour tissue the correlation between the number of mast cells positive to tryptase (MCPT), c-KitR expressing cells (c-KitR-EC), and microvascular density (MVD). Results. Data demonstrated a positive correlation between MCPT, c-KitR-EC, and MVD to each other. In tumour tissue the mean number of MCPT was 15, the mean number of c-KitR-EC was 20, and the mean number of MVD was 20. The Pearson test correlating MCPT and MVD, c-KitR-EC and MVD was significantly (r = 0.64, P = 0.001; r = 0.66, P = 0.041, resp.). Conclusion. In this pilot study, we suggest that MCPT and c-KitR-EC play a role in gastric cancer angiogenesis, so we think that several c-KitR or tryptase inhibitors such as gabexate mesilate and nafamostat mesilate might be evaluated in clinical trials as a new antiangiogenetic approach. PMID:24348541

Sacco, Rosario; Sammarco, Giuseppe; Donato, Giuseppe; Zuccalà, Valeria; Romano, Roberto; Luposella, Maria; Patruno, Rosa; Vallicelli, Carlo; Verdecchia, Giorgio Maria; Cavaliere, Davide; Montemurro, Severino; Ranieri, Girolamo

2013-01-01

379

AutoCorrel II: a neural network event correlation approach  

NASA Astrophysics Data System (ADS)

As a follow-up to our earlier model Autocorrel I, we have implemented a two-stage event correlation approach with improved performance. Like Autocorrel I, the new model correlates intrusion detection system (IDS) alerts to automate alert and incidents management, and reduce the workload on an IDS analyst. We achieve this correlation by clustering similar alerts, thus allowing the analyst to only consider a few clusters rather than hundreds or thousands of alerts. The first stage uses an artificial neural network (ANN)-based autoassociator (AA). The AA's objective is to attempt to reproduce each alert at its output. In the process, it uses an error metric, the reconstruction error (RE), between its input and output to cluster similar alerts. In order to improve the accuracy of the system we add another machine-learning stage which takes into account the RE as well as raw attribute information from the input alerts. This stage uses the Expectation-Maximisation (EM) clustering algorithm. The performance of this approach is tested with intrusion alerts generated by a Snort IDS on DARPA's 1999 IDS evaluation data as well as incidents.org alerts.

Dondo, Maxwell G.; Mason, Peter; Japkowicz, Nathalie; Smith, Reuben

2007-04-01

380

The perception of the environment is a major issue in autonomous robots. In our previous works, we have proposed a  

E-print Network

-to-contact. Velocity, distance, and time are intrinsically linked together [9]. In 1895, Karl Pearson published a new method for Collision Risk Estimation based on Pearson's Correlation Coefficient (PCC). Applying the Pearson's Correlation Coefficient (PCC) [10]. The Pearson's method is widely used in statistical analysis

Paris-Sud XI, Université de

381

Measurement and Correlation of Ambient VOCs in Windsor, Ontario, Canada and Detroit, Michigan, USA  

NASA Astrophysics Data System (ADS)

An air quality study has been carried out in Windsor, Ontario, Canada and Detroit, Michigan, USA as part of a pilot research study undertaken by the Geospatial Determinants of Health Outcomes Consortium (GeoDHOC), a multidisciplinary, international effort aimed at understanding the health effects of air pollution in urban environments. Exposure to volatile organic compounds has long been associated with adverse health conditions such as atrophy of skeletal muscles, loss of coordination, neurological damage, dizziness, throat, nose, and eye irritation, nervous system depression, liver damage, and respiratory symptoms. Twenty-six species of ambient volatile organic compounds (VOCs) were monitored during a 2-week period in September, 2008 at 100 sites across Windsor and Detroit, using 3M # 3500 Organic Vapour Monitors. Ten species with highest concentrations were selected for further investigation; Toluene (mean concentration =4.14 ?m/m3), (m+p)-Xylene (2.30 ?m/m3), Hexane (1.87 ?m/m3), Benzene (1.37 ?m/m3), 1,2,4-Trimethylbenzene (0.87 ?m/m3), Dichloromethane (0.77 ?m/m3), Ethylbenzene (0.68 ?m/m3), o-Xylene (0.63 ?m/m3), n-Decane (0.42 ?m/m3), and 1,3,5-Trimethylbenzene (0.39 ?m/m3). Comparison to a similar investigation in Sarnia, Ontario in October 2005 revealed that the mean concentrations of VOCs were higher in Windsor-Detroit for all species by a significant margin (31-958%), indicating substantial impact of local industrial and vehicular emissions in the WindsorVDetroit area. For most VOCs, the concentrations were higher in Detroit than in Windsor. The mean concentration of total VOC was 9.7 ?m/m3 in Windsor, which is slightly higher than that in Sarnia in 2005 (7.9 um/m3), whilst total VOC concentration in Detroit was much higher (16.5 ?m/m3). There were strong correlations among several of the 10 species, with the highest Pearson correlation coefficients (r=0.78 - 0.99, p<0.05) amongst the BTEX (benzene, toluene, ethylbenzene, and xylenes) group, suggesting common sources of these species. The BTEX correlation for this study was in good agreement with that from the Sarnia results (Spearman rank correlation coefficient r=0.75 - 0.99), suggesting that one species may act as a proxy for the others in geographically similar regions.

Miller, L. J.; You, H.; Xu, X.; Molaroni, S.; Lemke, L.; Weglicki, L.; Krouse, H.; Krajenta, R.

2009-05-01

382

Correlation, functional analysis and optical pattern recognition  

SciTech Connect

Correlation integrals have played a central role in optical pattern recognition. The success of correlation, however, has been limited. What is needed is a mathematical operation more complex than correlation. Suitably complex operations are the functionals defined on the Hilbert space of Lebesgue square integrable functions. Correlation is a linear functional of a parameter. In this paper, we develop a representation of functionals in terms of inner products or equivalently correlation functions. We also discuss the role of functionals in neutral networks. Having established a broad relation of correlation to pattern recognition, we discuss the computation of correlation functions using acousto-optics.

Dickey, F.M.; Lee, M.L.; Stalker, K.T.

1994-03-01

383

Iterative method for generating correlated binary sequences.  

PubMed

We propose an efficient iterative method for generating random correlated binary sequences with a prescribed correlation function. The method is based on consecutive linear modulations of an initially uncorrelated sequence into a correlated one. Each step of modulation increases the correlations until the desired level has been reached. The robustness and efficiency of the proposed algorithm are tested by generating sequences with inverse power-law correlations. The substantial increase in the strength of correlation in the iterative method with respect to single-step filtering generation is shown for all studied correlation functions. Our results can be used for design of disordered superlattices, waveguides, and surfaces with selective transport properties. PMID:25493902

Usatenko, O V; Melnik, S S; Apostolov, S S; Makarov, N M; Krokhin, A A

2014-11-01

384

Uranium nitride fuel swelling correlation  

NASA Astrophysics Data System (ADS)

A volumetric swelling correlation for UN fuel with Nb-1% Zr and PWC-11 cladding materials for application to space nuclear power systems was developed as: ?V/ V(%) = 4.7 × 10 -11TaV3.12Bu 0.83?0.5, where Tav is the volume averaged fuel temperature in K, Bu is the fuel burnup (at%), and ? is the as-fabricated fuel density (% of theoretical). This swelling correlation was within ± 25% of the data at burnups in excess of 1.12 at%. However, the scatter of the data at lower burnups resulted in a deviation as high as ± 60%. The reported swelling behavior of the Ta-111 clad fuel pins was consistent with that of the Nb-1% Zr and PWC-11 clad fuel pins. Analysis of W-26% Re clad UN fuel pins was inconclusive because of large scatter and inconsistencies in the data, and reported cladding failures in some tests.

Ross, Steven B.; El-Genk, Mohamed S.; Matthews, R. Bruce

1990-02-01

385

Counterion Correlations on Condensed Biopolymers  

NASA Astrophysics Data System (ADS)

Like-charged polyelectrolytes condense into ordered phases in the presence of multivalent ions. The physical origin of the attractive interaction required for this condensation has been intensely debated, but no clear consensus has emerged, although counterion correlations appear to play a key role. In order to elucidate the nature of these interactions, we have performed structural measurements of condensed phases formed between multivalent ions and a range of rod-like polyelectrolytes, including cytoskeletal F-actin, and Fd and M13 filamentary virus particles.šDirect measurements of the counterion density and correlations in different condensed phases will be presented, along with the temperature dependence of these phases. This work was supported by NSF DMR-0071761, DOE DEFG02-91ER45439, the Beckman Young Investigator Program, and the Cystic Fibrosis Foundation.

Angelini, Tommy; Butler, John; Ho, James; Liang, Hongjun; Wong, Gerard

2002-03-01

386

Correlation of cavitating centrifugal pumps  

NASA Astrophysics Data System (ADS)

The foreknowledge of the minimum NPSH ('net positive suction head') required for a cavitation-free performance of centrifugal pumps is important for a safe and sound operation of these machines. The required NPSH varies from pump to pump, from fluid to fluid, and from temperature to temperature of the pumped fluid. This is known as the thermodynamic effect. The methods currently used for the correlation and analysis of this condition are not always reliable because of the multi-variable nature of the cavitation process. In this paper, two new methods are proposed which lead to more consistent correlations of the required minimum NPSH; thus they can also be used for more dependable predictions of the net positive suction head for any pump, fluid and temperature. The predictions by the two methods do not coincide, but outline a narrow band of probability, within which the actual test points are invariably located.

Zika, V. J.

1984-06-01

387

Exascale cross correlation in software  

NASA Astrophysics Data System (ADS)

The exascale computational demands of back-end processing in the era of the SKA headlined by the needs of cross-correlation, are likely to require solutions that differ significantly from traditional approaches on smaller arrays. Software approaches are already capable of achieving petascale processing using massively-parallel general-purpose computing hardware. We discuss the advantages and practical issues surrounding this approach and probe what will ultimately be needed to reach the exascale.

Clark, M. A.; Barsdell, B. R.; Greenhill, L. J.

2014-04-01

388

Genotypic-Phenotypic Correlative Studies  

Cancer.gov

The CBRG is a co-sponsor of the Cooperative Family Registry for Colon Cancer, established to support genotypic-phenotpic-correlative studies. The necessity for elucidating the relationship between genotype and phenotype is becoming particularly important when detection methods uncover changes in the genomic DNA without knowing if the changes are causing changes in the phenotype or if the phenotype has an association with clinical outcome.

389

Electrophysiological correlates of change detection  

Microsoft Academic Search

Abstract To identify electrophysiological correlates of change detection, event-related brain potentials (ERPs) were recorded while participants monitored,displays containing four faces in order to detect a face identity change across successive displays. Successful change detection was mirrored by an N2pc component,at posterior electrodes contralateral to the side of a change, suggesting close links between conscious change detection and attention. ERPs on

Martin Eimer; Veronica Mazza

2005-01-01

390

Observability transitions in correlated networks  

NASA Astrophysics Data System (ADS)

Yang, Wang, and Motter [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.109.258701 109, 258701 (2012)] analyzed a model for network observability transitions in which a sensor placed on a node makes the node and the adjacent nodes observable. The size of the connected components comprising the observable nodes is a major concern of the model. We analyze this model in random heterogeneous networks with degree correlation. With numerical simulations and analytical arguments based on generating functions, we find that negative degree correlation makes networks more observable. This result holds true both when the sensors are placed on nodes one by one in a random order and when hubs preferentially receive the sensors. Finally, we numerically optimize networks with a fixed degree sequence with respect to the size of the largest observable component. Optimized networks have negative degree correlation induced by the resulting hub-repulsive structure; the largest hubs are rarely connected to each other, in contrast to the rich-club phenomenon of networks.

Hasegawa, Takehisa; Takaguchi, Taro; Masuda, Naoki

2013-10-01

391

Correlated Temporal and Spectral Variability  

NASA Technical Reports Server (NTRS)

The variability of neutron star and black hole X-ray sources has several dimensions, because of the roles played by different important time-scales. The variations on time scales of hours, weeks, and months, ranging from 50% to orders of magnitude, arise out of changes in the flow in the disk. The most important driving forces for those changes are probably various possible instabilities in the disk, though there may be effects with other dominant causes. The changes in the rate of flow appear to be associated with changes in the flow's configuration, as the accreting material approaches the compact object, for there are generally correlated changes in both the Xray spectra and the character of the faster temporal variability. There has been a lot of progress in tracking these correlations, both for Z and Atoll neutron star low-mass X-ray binaries, and for black hole binaries. I will discuss these correlations and review briefly what they tell us about the physical states of the systems.

Swank, Jean H.

2007-01-01

392

Posttreatment FDG-PET Uptake in the Supraglottic and Glottic Larynx Correlates With Decreased Quality of Life After Chemoradiotherapy  

SciTech Connect

Purpose: Inflammation and increased metabolic activity associated with oxidative stress in irradiated normal tissues may contribute to both complications following radiotherapy and increased glucose uptake as detected by posttherapy fluorodeoxyglucose (FDG)-PET imaging. We sought to determine whether increased glucose uptake in normal tissues after chemoradiotherapy is associated with increased toxicity. Methods and Materials: Consecutive patients with locoregionally advanced head and neck cancers treated with intensity-modulated radiation therapy and free of recurrence at 1 year were studied. FDG-PET imaging was obtained at 3 and 12 months posttreatment. Standardized uptake value (SUV) levels were determined at various head and neck regions. Functional outcome was measured using a quality of life questionnaire and weight loss and type of diet tolerated 1 year after therapy. A one-tailed Pearson correlation test was used to examine associations between SUV levels and functional outcome measures. Results: Standardized uptake value levels in the supraglottic and glottic larynx from FDG-PET imaging obtained 12 months posttreatment were inversely associated with quality of life measures and were correlated with a more restricted diet 1 year after therapy. SUV levels at 3 months after therapy did not correlate with functional outcome. Increases in SUV levels in normal tissues between 3 and 12 months were commonly found in the absence of recurrence. Conclusion: Altered metabolism in irradiated tissues persists 1 year after therapy. FDG-PET scans may be used to assess normal tissue damage following chemoradiotherapy. These data support investigating hypermetabolic conditions associated with either inflammation, oxidative stress, or both, as causal agents for radiation-induced normal tissue damage.

Dornfeld, Ken [Department of Radiation Oncology, Carver College of Medicine, University of Iowa, Iowa City, IA (United States)], E-mail: Kdornfeld@smdc.org; Hopkins, Shane; Simmons, Joel; Spitz, Douglas R. [Department of Radiation Oncology, Carver College of Medicine, University of Iowa, Iowa City, IA (United States); Menda, Yusuf; Graham, Michael [Department of Nuclear Medicine, The Carver College of Medicine, University of Iowa, Iowa City, IA (United States); Smith, Russell; Funk, Gerry; Karnell, Lucy; Karnell, Michael [Department of Otolaryngology-Head and Neck Surgery, Carver College of Medicine, University of Iowa, Iowa City, IA (United States); Dornfeld, Maude; Yao Min; Buatti, John [Department of Radiation Oncology, The Carver College of Medicine, University of Iowa, Iowa City, IA (United States)

2008-06-01

393

Correlation between BPI gene upstream CpG island methylation and mRNA expression in piglets.  

PubMed

Diarrhea and edematous disease are two major causes of mortality in postweaning piglets, and these conditions lead to huge economic losses in the swine industry. E. coli F18 is the primary causative agent of these two diseases. Bactericidal/permeability-increasing protein (BPI) plays an important role in the natural defense of the host. The aim of this study was to determine the correlation between BPI gene upstream CpG island methylation and mRNA expression. In this study, bisulfite sequencing PCR (BSP) was used to detect the methylation status of the BPI gene upstream CpG island and fluorescence quantitative PCR was used to detect BPI expression in the duodenum of piglets from birth to weaning age. BPI upstream CpG islands were shown to have many putative transcription factor binding sites, 10 CpG sites and every CpG site was methylated. The CpG island methylation level was lowest in 30-day piglets and was significantly lower than levels in 8-day piglets (p<0.05). BPI mRNA expression was significantly higher in 30-day piglets than at any other age (p<0.05). Pearson's correlation analysis showed that the methylation status of the CpG island was negatively correlated with BPI mRNA expression. Statistical significances were found in CpG_1, CpG_3, CpG_4, CpG_7 and CpG_10 (p<0.05). The data indicate that BPI expression is improved by demethylation of the BPI gene upstream CpG island. Furthermore, CpG_1, CpG_3, CpG_4, CpG_7 and CpG_10 may be critical sites in the regulation of BPI gene expression. PMID:24945309

Wang, Jing; Yin, Xuemei; Sun, Li; Sun, Shouyong; Zi, Chen; Zhu, Guoqiang; Wu, Shenglong; Bao, Wenbin

2014-01-01

394

Correlates of Willingness to Engage in Residential Gardening: Implications for Health Optimization in Ibadan, Nigeria  

PubMed Central

Background: Gardening is a worthwhile adventure which engenders health op­timization. Yet, a dearth of evidences that highlights motivations to engage in gardening exists. This study examined willingness to engage in gardening and its correlates, including some socio-psychological, health related and socio-demographic variables. Methods: In this cross-sectional survey, 508 copies of a structured questionnaire were randomly self administered among a group of civil servants of Oyo State, Nigeria. Multi-item measures were used to assess variables. Step wise multiple regression analysis was used to identify predictors of willingness to engage in gar­dening Results: Simple percentile analysis shows that 71.1% of respondents do not own a garden. Results of step wise multiple regression analysis indicate that descriptive norm of gardening is a good predictor, social support for gardening is better while gardening self efficacy is the best predictor of willingness to engage in gardening (P< 0.001). Health consciousness, gardening response efficacy, education and age are not predictors of this willingness (P> 0.05). Results of t-test and ANOVA respectively shows that gender is not associated with this willingness (P> 0.05), but marital status is (P< 0.05).  Conclusion: Socio-psychological characteristics and being married are very rele­vant in motivations to engage in gardening. The nexus between gardening and health optimization appears to be highly obscured in this population. PMID:24688974

Motunrayo Ibrahim, Fausat

2013-01-01

395

Pouch size after gastric bypass does not correlate with weight loss outcome.  

PubMed

A large gastric pouch is a classic explanation for weight loss problems after gastric bypass. However, several reports have emphasized the role of others, essentially behavorial, factors. We reviewed the outcomes of 151 patients who were operated on over a period of nearly 2 years. 132 patients who had not been reoperated on were assessed between June and September 2009. A barium swallow was available to assess the gastric pouch volume which was determined by the radiologist. %EWL was compared to the pouch volume using ANOVA test. Pouch volumes were compared using t test. The gastric pouch was dilated when >50 ml and failure to lose enough weight was defined by a %EWL<50%. 107 patients (81%) had a complete follow up of 35.7?±?5.8 months. Mean pouch volume was 68?±?4.5 ml with a %EWL of 68?±?26.1%. 59 patients had a large pouch with a weight loss similar to those with a normally sized pouch (68?±?3.6 vs 66?±?3.6%EWL). 25 patients (23.3%) had weight loss failure with a similar pouch volume. No correlation was found between the %EWL and the pouch volume. Pouch size probably plays a role in the weight loss process of RYGB. However, 3 years later, pouch volume does not appear to be the most important factor. Behavorial factors such as recurrent eating disorders and failure to adapt to the changes induced by the surgery may explain at least in part weight loss failure. PMID:21660641

Topart, Philippe; Becouarn, Guillaume; Ritz, Patrick

2011-09-01

396

Correlation of Tinnitus Loudness and Onset Duration with Audiological Profile Indicating Variation in Prognosis  

PubMed Central

Purpose. Subjective tinnitus has different forms and degrees of severity. Many studies in the literature have assessed psychoacoustic characteristics of tinnitus but hardly any of them had focused on the association of audiological profile with onset duration and loudness perception. The aim of this study was to evaluate existence of any association between tinnitus loudness/onset duration and audiological profile to explain differences in prognosis. Method. Study design was prospective. The sample consisted of 26 subjects having tinnitus, which was divided into tinnitus and nontinnitus ears. Audiological profile included pure-tone audiometry, speech audiometry, tympanometry, acoustic reflex test, and auditory evoked potentials (early and middle latency). Unpaired t-test was applied to compare two subgroups. Correlation and association between tinnitus onset duration/loudness perception and audiological profile were also assessed by calculating Spearman's coefficient and Fischer exact value. Results. The two subgroups had significant differences for pure-tone and speech audiometry hearing thresholds. A significant association was observed between the high frequency/extended high frequency and tinnitus loudness/onset duration. Conclusion. The changes in hearing thresholds and auditory pathway are associated with an increase in tinnitus loudness and its onset duration. This knowledge would be helpful to differentiate between severity and chronicity of the patients for planning therapeutic management and predicting prognosis. PMID:24078882

Munjal, Sanjay K.; Panda, Naresh K.; Verma, Roshan K.

2013-01-01

397

Preselected Sub-Poissonian Correlations  

NASA Technical Reports Server (NTRS)

The simplest possible photon-number-squeezed states containing only two photons and exhibiting sub-poissonian statistics with the Fano factor approaching 0.5 have been used for a proposal of a loophole-free Bell experiment requiring only 67 percent of detection efficiency. The states are obtained by the fourth order interference first of two downconverted photons at an asymmetrical beam splitter and thereupon of two photons from two independent singlets at an asymmetrical beam splitter. In the latter set-up, the other two photons which nowhere interacted and whose paths never crossed appear entangled in a singlet-like correlated state.

Pavicic, Mladen

1996-01-01

398

Speeding up local correlation methods  

NASA Astrophysics Data System (ADS)

We present two techniques that can substantially speed up the local correlation methods. The first one allows one to avoid the expensive transformation of the electron-repulsion integrals from atomic orbitals to virtual space. The second one introduces an algorithm for the residual equations in the local perturbative treatment that, in contrast to the standard scheme, does not require holding the amplitudes or residuals in memory. It is shown that even an interpreter-based implementation of the proposed algorithm in the context of local MP2 method is faster and requires less memory than the highly optimized variants of conventional algorithms.

Kats, Daniel

2014-12-01

399

Star polymers in correlated disorder  

E-print Network

We analyze the impact of a porous medium (structural disorder) on the scaling of the partition function of a star polymer immersed in a good solvent. We show that corresponding scaling exponents change if the disorder is long-range-correlated and calculate the exponents in the new universality class. A notable finding is that star and chain polymers react in qualitatively different manner on the presence of disorder: the corresponding scaling exponents increase for chains and decrease for stars. We discuss the physical consequences of this difference.

V. Blavats'ka; C. von Ferber; Yu. Holovatch

2007-11-23

400

OPTIMAL CORRELATION ESTIMATORS FOR QUANTIZED SIGNALS  

SciTech Connect

Using a maximum-likelihood criterion, we derive optimal correlation strategies for signals with and without digitization. We assume that the signals are drawn from zero-mean Gaussian distributions, as is expected in radio-astronomical applications, and we present correlation estimators both with and without a priori knowledge of the signal variances. We demonstrate that traditional estimators of correlation, which rely on averaging products, exhibit large and paradoxical noise when the correlation is strong. However, we also show that these estimators are fully optimal in the limit of vanishing correlation. We calculate the bias and noise in each of these estimators and discuss their suitability for implementation in modern digital correlators.

Johnson, M. D.; Chou, H. H.; Gwinn, C. R., E-mail: michaeltdh@physics.ucsb.edu, E-mail: cgwinn@physics.ucsb.edu [Department of Physics, University of California, Santa Barbara, CA 93106 (United States)

2013-03-10

401

Angularly anisotropic correlation in granular packings  

NASA Astrophysics Data System (ADS)

We present an x-ray microtomography study of the three-dimensional structural correlations in monodisperse granular packings. By measuring an orientation-dependent pair correlation function, we find that the local structure shows an angularly anisotropic orientation correlation. The correlation is strongest along the major axis of the local Minkowski tensor of the Voronoi cell. It turns out that this anisotropic correlation is consistent with the existence of some locally favored structures. The study suggests the importance of high-order structural correlations in random granular packings.

Xia, Chengjie; Cao, Yixin; Kou, Binquan; Li, Jindong; Wang, Yujie; Xiao, Xianghui; Fezzaa, Kamel

2014-12-01

402

Gene regulatory network inference from multifactorial perturbation data using both regression and correlation analyses.  

PubMed

An important problem in systems biology is to reconstruct gene regulatory networks (GRNs) from experimental data and other a priori information. The DREAM project offers some types of experimental data, such as knockout data, knockdown data, time series data, etc. Among them, multifactorial perturbation data are easier and less expensive to obtain than other types of experimental data and are thus more common in practice. In this article, a new algorithm is presented for the inference of GRNs using the DREAM4 multifactorial perturbation data. The GRN inference problem among [Formula: see text] genes is decomposed into [Formula: see text] different regression problems. In each of the regression problems, the expression level of a target gene is predicted solely from the expression level of a potential regulation gene. For different potential regulation genes, different weights for a specific target gene are constructed by using the sum of squared residuals and the Pearson correlation coefficient. Then these weights are normalized to reflect effort differences of regulating distinct genes. By appropriately choosing the parameters of the power law, we constructe a 0-1 integer programming problem. By solving this problem, direct regulation genes for an arbitrary gene can be estimated. And, the normalized weight of a gene is modified, on the basis of the estimation results about the existence of direct regulations to it. These normalized and modified weights are used in queuing the possibility of the existence of a corresponding direct regulation. Computation results with the DREAM4 In Silico Size 100 Multifactorial subchallenge show that estimation performances of the suggested algorithm can even outperform the best team. Using the real data provided by the DREAM5 Network Inference Challenge, estimation performances can be ranked third. Furthermore, the high precision of the obtained most reliable predictions shows the suggested algorithm may be helpful in guiding biological experiment designs. PMID:23028471

Xiong, Jie; Zhou, Tong

2012-01-01

403

Organic pollutants and their correlation with stable isotopes in vegetation from King George Island, Antarctica.  

PubMed

Vegetation samples from King George Island, Antarctica (62°05'S, 058°23'W) were collected in the austral summer of 2004-2005. Lichens (Usnea aurantiaco-atra and Usnea antarctica), mosses (Sanionia uncinata, Syntrichia princeps and Brachytecium sp.), and one angiosperm (Colobanthus quitensis) species were analyzed for persistent organic pollutants as well as ?(13)C and ?(15)N stable isotopes. The following contaminants were found above the method detection limit (MDL): HCB (0.141-1.06 ng g(-1) dry weight), HCHs (Pearson's correlation showed significant results for some contaminants (e.g. HCHs/HCB and PCBs/DDTs) and suggested the influence of the origin of both nitrogen and pollutants, notably taking secondary sources (animal excrements/remains, for instance) into consideration. PMID:21868055

Cipro, Caio V Z; Yogui, Gilvan Takeshi; Bustamante, Paco; Taniguchi, Satie; Sericano, José L; Montone, Rosalinda Carmela

2011-10-01

404

Inferring correlations: from exemplars to categories.  

PubMed

Research and theorizing suggest a processing advantage of category-level correlations over exemplar-level correlations. That research has also shown that category-level correlations serve as a proxy for inferring exemplar-level correlations. For example, an individual may learn that the demand for a product category, like cheese, in one store predicts the demand for this category in another. The individual could then draw the unwarranted conclusion that the demand for an exemplar, like cheddar, would also predict the demand for this exemplar in the other store. This notion is supported by previous experiments demonstrating that the subjective exemplar-level correlation follows the implication of the category-level correlation. However, in virtually all previous experiments suggesting a processing advantage for category-level over exemplar-level correlations, the stimulus correlation at the category level was substantial, whereas the correlation at the exemplar level was weak. Here, we tested the hypothesis that individuals process the level that is most informative, either the exemplar or the category level. We presented participants with a zero correlation at the category level, but varied the correlation at the exemplar level. Participants presented with a zero correlation across exemplar products correctly reproduced a zero correlation across product categories. When presented with a substantial correlation at the exemplar level, however, they erroneously reproduced a similar correlation at the category level. These findings therefore imply that there is no general processing advantage for correlations at higher aggregation levels. Instead, individuals seemingly attend to the level that holds the most regular information. Findings are discussed regarding the role of covariation strength in correlation detection and use. PMID:24493021

Vogel, Tobias; Kutzner, Florian; Freytag, Peter; Fiedler, Klaus

2014-10-01

405

Exercising calf muscle changes correlate with pH, PCr recovery and maximum oxidative phosphorylation  

PubMed Central

Skeletal muscle metabolism is impaired in disorders like diabetes mellitus or peripheral vascular disease. The skeletal muscle echo planar imaging (EPI) signal (SEPI) and its relation to energy metabolism are still debated. Localised 31P MRS and SEPI data from gastrocnemius medialis of 19 healthy subjects were combined in one scanning session to study direct relationships between phosphocreatine (PCr), pH kinetics and parameters of time courses. Dynamic spectroscopy (semi-LASER) and EPI were performed immediately before, during and after 5?min of plantar flexions. Data were acquired in a 7?T MR scanner equipped with a custom-built ergometer and a dedicated 31P/1H radio frequency (RF) coil array. Using a form-fitted multi-channel 31P/1H coil array resulted in high signal-to-noise ratio (SNR). PCr and pH in the gastrocnemius medialis muscle were quantified from each 31P spectrum, acquired every 6?s. During exercise, SEPI(t) was found to be a linear function of tissue pH(t) (cross-correlation r?=?–0.85?±?0.07). Strong Pearson's correlations were observed between post exercise time-to-peak (TTP) of SEPI and (a) the time constant of PCr recovery ?PCr?recovery (r?=?0.89, p?correlations of the skeletal muscle SEPI during exercise and tissue pH time courses and of post exercise SEPI and parameters of energy metabolism were observed. In conclusion, a tight coupling between skeletal muscle metabolic activity and tissue signal weighting, probably induced by osmotically driven water shift, exists and can be measured non-invasively, using NMR at 7?T. PMID:24610788

Schmid, Albrecht Ingo; Schewzow, Kiril; Fiedler, Georg Bernd; Goluch, Sigrun; Laistler, Elmar; Wolzt, Michael; Moser, Ewald; Meyerspeer, Martin

2014-01-01

406

The dynamics of correlated novelties.  

PubMed

Novelties are a familiar part of daily life. They are also fundamental to the evolution of biological systems, human society, and technology. By opening new possibilities, one novelty can pave the way for others in a process that Kauffman has called "expanding the adjacent possible". The dynamics of correlated novelties, however, have yet to be quantified empirically or modeled mathematically. Here we propose a simple mathematical model that mimics the process of exploring a physical, biological, or conceptual space that enlarges whenever a novelty occurs. The model, a generalization of Polya's urn, predicts statistical laws for the rate at which novelties happen (Heaps' law) and for the probability distribution on the space explored (Zipf's law), as well as signatures of the process by which one novelty sets the stage for another. We test these predictions on four data sets of human activity: the edit events of Wikipedia pages, the emergence of tags in annotation systems, the sequence of words in texts, and listening to new songs in online music catalogues. By quantifying the dynamics of correlated novelties, our results provide a starting point for a deeper understanding of the adjacent possible and its role in biological, cultural, and technological evolution. PMID:25080941

Tria, F; Loreto, V; Servedio, V D P; Strogatz, S H

2014-01-01

407

The dynamics of correlated novelties  

NASA Astrophysics Data System (ADS)

Novelties are a familiar part of daily life. They are also fundamental to the evolution of biological systems, human society, and technology. By opening new possibilities, one novelty can pave the way for others in a process that Kauffman has called ``expanding the adjacent possible''. The dynamics of correlated novelties, however, have yet to be quantified empirically or modeled mathematically. Here we propose a simple mathematical model that mimics the process of exploring a physical, biological, or conceptual space that enlarges whenever a novelty occurs. The model, a generalization of Polya's urn, predicts statistical laws for the rate at which novelties happen (Heaps' law) and for the probability distribution on the space explored (Zipf's law), as well as signatures of the process by which one novelty sets the stage for another. We test these predictions on four data sets of human activity: the edit events of Wikipedia pages, the emergence of tags in annotation systems, the sequence of words in texts, and listening to new songs in online music catalogues. By quantifying the dynamics of correlated novelties, our results provide a starting point for a deeper understanding of the adjacent possible and its role in biological, cultural, and technological evolution.

Tria, F.; Loreto, V.; Servedio, V. D. P.; Strogatz, S. H.

2014-07-01

408

The Neurogenetic Correlates of Consciousness  

NASA Astrophysics Data System (ADS)

The neurogenetic correlates of consciousness (NgCC) is a new field of consciousness studies that focuses on genes that have an effect on or are involved in the continuum of neuron-based consciousness. A framework of consciousness based on the neural correlates of consciousness (NCC) has already been established by Francis Crick and Christof Kock. In this work I propose that there are NgCC underlying the NCC which are both active during the conscious experience. So how are genes involved? There are two significant connections between DNA and neurons that are involved in the conscious experience. First, any brain system can be adversely affected by underlying genetic abnormalities which can be expressed in an individual at birth, in adulthood, or later in life. Second, the DNA molecule does not lay dormant while the neuron runs on autopilot. DNA is active in translating and transcribing RNA and protein products that are utilized during neuron functioning. Without these products being continuously produced by the DNA during a conscious experience the neurons would cease to function correctly and be rendered unable to provide a continuum of human consciousness. Consequently, in addition to NCC, NgCC must be factored in when appreciating a conscious event. In this work I will discuss and explain some NgCC citing several examples.

Grandy, John K.

2013-09-01

409

Tranverse correlation of quasar pairs  

NASA Astrophysics Data System (ADS)

For the last five billion years the universe has been expanding in size at an increasing rate. With modern technology we are able to observe objects at very high redshift, which were created in the early universe. Being able to analyze and observe these objects allows us to put specific constraints on the universe (age, size, dark matter fraction…etc). Looking at the spectra of highly redshifted objects, such as quasars, we can see a series of absorption lines called the Lyman alpha forest.The angular correlation in the Lyman alpha spectra of quasar pairs allows us to measure the size of the absorbing objects. This works best at very small-scale (below one arcmin). The most recent use of this method consisted of 32 quasar pairs and only two of those had a sky separation below 1 arcmin (Coppolani et al., 2006). The sample size that is used in this work is from the SDSS-III DR12. This catalog has over 1500 quasars pairs below two arcmin separation, giving us much lower error bars, and therefore putting much better constraints on the cosmological parameters that can be inferred from the correlation function

Paris, Isabelle; BOSS/SDSS

2015-01-01

410

Astrochemical Correlations in Molecular Clouds  

NASA Astrophysics Data System (ADS)

We investigate the spectral correlations between different species used to observe molecular clouds. We use hydrodynamic simulations and a full chemical network to study the abundances of over 150 species in typical Milky Way molecular clouds. We perform synthetic observations in order to produce emission maps of a subset of these tracers. We study the effects of different lines of sight and spatial resolution on the emission distribution and perform a robust quantitative comparison of the species to each other. We use the Spectral Correlation Function (SCF), which quantifies the root mean squared difference between spectra separated by some length scale, to characterize the structure of the simulated cloud in position-position-velocity (PPV) space. We predict the observed SCF for a broad range of observational tracers, and thus identify homologous species. In particular, we show that the pairs C and CO, C+ and CN, and NH3 and H2CS have very similar SCFs. We measure the SCF slope variation as a function of beam size for all species and demonstrate that the beam size has a distinct effect on different species emission. However, for beams of up to 10'', placing the cloud at 1 kpc, the change is not large enough to move the SCF slopes into different regions of parameter space. The results from this study provide observational guidance for choosing the best tracer to probe various cloud length scales.

Gaches, Brandt A. L.; Offner, Stella S. R.; Rosolowsky, Erik W.; Bisbas, Thomas G.

2015-02-01

411

Cortical Correlates of Fitts’ Law  

PubMed Central

Fitts’ law describes the fundamental trade-off between movement accuracy and speed: it states that the duration of reaching movements is a function of target size (TS) and distance. While Fitts’ law has been extensively studied in ergonomics and has guided the design of human–computer interfaces, there have been few studies on its neuronal correlates. To elucidate sensorimotor cortical activity underlying Fitts’ law, we implanted two monkeys with multielectrode arrays in the primary motor (M1) and primary somatosensory (S1) cortices. The monkeys performed reaches with a joystick-controlled cursor toward targets of different size. The reaction time (RT), movement time, and movement velocity changed with TS, and M1 and S1 activity reflected these changes. Moreover, modifications of cortical activity could not be explained by changes of movement parameters alone, but required TS as an additional parameter. Neuronal representation of TS was especially prominent during the early RT period where it influenced the slope of the firing rate rise preceding movement initiation. During the movement period, cortical activity was correlated with movement velocity. Neural decoders were applied to simultaneously decode TS and motor parameters from cortical modulations. We suggest that sensorimotor cortex activity reflects the characteristics of both the movement and the target. Classifiers that extract these parameters from cortical ensembles could improve neuroprosthetic control. PMID:22275888

Ifft, Peter J.; Lebedev, Mikhail A.; Nicolelis, Miguel A. L.

2011-01-01

412

Fiducial marker for correlating images  

DOEpatents

The invention relates to a fiducial marker having a marking grid that is used to correlate and view images produced by different imaging modalities or different imaging and viewing modalities. More specifically, the invention relates to the fiducial marking grid that has a grid pattern for producing either a viewing image and/or a first analytical image that can be overlaid with at least one other second analytical image in order to view a light path or to image different imaging modalities. Depending on the analysis, the grid pattern has a single layer of a certain thickness or at least two layers of certain thicknesses. In either case, the grid pattern is imageable by each imaging or viewing modality used in the analysis. Further, when viewing a light path, the light path of the analytical modality cannot be visualized by viewing modality (e.g., a light microscope objective). By correlating these images, the ability to analyze a thin sample that is, for example, biological in nature but yet contains trace metal ions is enhanced. Specifically, it is desired to analyze both the organic matter of the biological sample and the trace metal ions contained within the biological sample without adding or using extrinsic labels or stains.

Miller, Lisa Marie (Rocky Point, NY); Smith, Randy J. (Wading River, NY); Warren, John B. (Port Jefferson, NY); Elliott, Donald (Hampton Bays, NY)

2011-06-21

413

Copyright 2012 Pearson Education, Inc. Table of Contents  

E-print Network

to students. Included in this manual is all the information you will need to use Maple in the instruction Fields and Graphical Solutions 72 Symbolic Solutions to Second Order ODEs and IVPs 76 Expressions: Graphical Analysis Using Direction Fields) 102 3. Laboratory Two (Numerical Solutions by Euler's Method) 108

Ding, Wandi

414

2005 Pearson Education Inc., publishing as Addison-Wesley  

E-print Network

value over time. ·More distant supernovae are dimmer than expected ·Something ("Dark Energy") is causing the expansion to accelerate. We don't know what Dark Energy is ­ only that it appears breath you take: the big bang is all around us. It is a theory, but a theory with a web of evidence

Shirley, Yancy

415

ESTIMATION OF WATER QUALITY CRITERIA VIOLATION FREQUENCIES USING PEARSON PERCENTILES  

EPA Science Inventory

A numerical technique is developed for estimating water quality violation frequencies due to pollutant discharges from urban areas during combined sewer overflow events. The first four moments of in-stream pollutant concentration are found by integrating a pollutant loading - wat...

416

Standardized Pearson type 3 density function area tables  

NASA Technical Reports Server (NTRS)

Tables constituting extension of similar tables published in 1936 are presented in report form. Single and triple parameter gamma functions are discussed. Report tables should interest persons concerned with development and use of numerical analysis and evaluation methods.

Cohen, A. C.; Helm, F. R.; Sugg, M.

1971-01-01

417

TP 7 -Test de Neyman Pearson. Rapport de vraisemblance monotone.  

E-print Network

échantillon (X1, . . . , Xn) de loi N(, 2). On souhaite tester l'hypothèse H0 : « = 0 »contre l'alternative H de la puissance de ce test. 4. Que suggérez-vous pour augmenter la puissance du test ? 5. On désire1 et calculer la fréquence empirique des cibles non détectées. 8. Une antenne de communication

Gadat, Sébastien

418

2005 Pearson Education South Asia Pte Ltd Applied Fluid Mechanics  

E-print Network

, and atmospheric pressure. 2. Describe the degree of variation of atmospheric pressure near Earth's surface. 3. Describe the properties of air at standard atmospheric pressure. 4. Describe the properties-type manometer. 8. Describe a barometer and how it indicates the value of the local atmospheric pressure. 9

Leu, Tzong-Shyng "Jeremy"

419

Karl Pearson and the Establishment of Mathematical Statistics  

Microsoft Academic Search

At the end of the nineteenth century, the content and practice of statistics underwent a series of transitions that led to its emergence as a highly specialised mathematical discipline. These intellectual and later institutional changes were, in part, brought about by a mathematical-statistical translation of Charles Darwin's redefinition of the biological species as something that could be viewed in terms

M. Eileen Magnello

2009-01-01

420

The Epistemology of Natural Science and Mr. Karl Pearson  

Microsoft Academic Search

FOR our Principle of Inertia the Germans use two expressions, Trägheitsprincip and Trägheitsgesetz. Dr. Volkmann in his work almost invariably adopts the latter, and even speaks of the principle of inertia as das physikalische Gesetz der Trägheit. If a physical law be not a law of nature, Dr. Volkmann ought to have carefully distinguished between a Naturgesetz and a physikalisches

Karl Pearson

1897-01-01

421

HelenPearson,NewYork Africa should pursue agricultural research  

E-print Network

,forexample,thatnewstrainsof crops win market access.This is seen as essential in providing farmers with secure income and helping harvest getting to market. These issues need to be addressed alongside the scientific ones, says Peter, the bioethics committee of the Council for Science and Technology Policy,Japan's main scientific decision

Cai, Long

422

MARKARIAN 501 MONITORING CAMPAIGN USING ROVOR Richard L. Pearson III  

E-print Network

for their continued sup- port and funding of the ROVOR project, making this and other senior projects possible. #12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2.1 Software Bisque Packages . . . . . . . . . . . . . . . . . . . . 8 2.2.2 LabView Programs

Hart, Gus

423

252 biochemical serum profile and laparoscopic ovum pickup correlation in anglo nubian goats fed with different fat sources.  

PubMed

The aim of the present study was to evaluate the correlations between biochemical serum profile with total number of aspirated follicles (AF), oocytes recovered (OR), number of corpus lutea (CL), oocyte morphology quality, and oocyte in vitro maturation (IVM) rate. Eighteen goats were randomly divided into 3 groups based on treatment diets, with different fat sources [soy oil (SG, n=6), linseed (LG, n=6), and Megalac® (MG, n=6)], formulated with 40% concentrate, 60% corn silage, of which 4% was ether extract from fat sources. The animals were submitted to a 15-day adaptation period and then a 70-day experimental period. The laparoscopic ovum pickup (LOPU) was performed after 36h of an ovarian superstimulation protocol [FSH (80mg)+eCG (300IU)] on Day 42 (LOPU1) and Day 70 (LOPU2) of the trial. The number of AF, and the presence and number of CL were evaluated during the LOPU procedure. Blood samples were taken at 14 days, 7 days, and just before each LOPU, and grouped as P1 (mean of blood samples results obtained before LOPU1) and P2 (LOPU2); serum metabolites analysed were total cholesterol, triglycerides, aspartate aminotransferase (AST), creatine kinase, and plasma glucose. The recovered oocytes were classified by morphological appearance, and only G1 (homogenous ooplasma and at least 3 layers of cumulus cells), G2 (homogenous ooplasma and at least 1 complete layers of cumulus cells), and G3 (homogenous ooplasma and incomplete layers or no cumulus cells) were submitted to IVM. The oocytes were incubated in maturation media (TCM 199 supplemented with 10% heat inactivated goat serum) at 38.5°C and 5% CO2 for 27h. Then, oocytes were subsequently fixed and stained on Hoechst 33342 and analysed using a fluorescent microscope for nuclear maturation. The IVM and analysis were performed for each individual. Pearson correlation test (P<0.05) was applied in R(®) software between serum metabolites and LOPU variables. The triglycerides, creatine kinase, and glucose were not correlated with any LOPU variables. The total cholesterol was negatively correlated with G1, G2, and CL, and positively correlated with OR and G3 with determination coefficients (R) of -0.28, -0.38, -0.24, 0.25, and 0.44, respectively. The AST were negatively correlated with AF, G1, G2, and IVM, with R of -0.11, -0.43, -0.13, and -0.16, respectively. In conclusion, these results are suggestive that high serum levels of cholesterol and AST may interfere with oocyte quality, indicating a negative hyperlipidemia effect on reproductive efficiency as reported in cows. PMID:25472300

Nociti, R P; Uscategui, R A R; Padilha, L C; Barros, F F P C; Motta, G A; Mariano, R S G; Rola, L C; Coelho, C M M; Santos, V J C; Feliciano, M A R; Vicente, W R R; Oliveira, M E F; Hossepian de Lima, V F M

2014-12-01

424

Dissemination of antibiotic resistance genes in representative broiler feedlots environments: identification of indicator ARGs and correlations with environmental variables.  

PubMed

Livestock operations are known to harbor elevated levels of antibiotic resistance genes (ARGs) that may pose a threat to public health. Broiler feedlots may represent an important source of ARGs in the environment. However, the prevalence and dissemination mechanisms of various types of ARGs in the environment of broiler feedlots have not previously been identified. We examined the occurrence, abundance and variation of ARGs conferring resistance to chloramphenicols, sulfonamides and tetracyclines in the environments of two representative types of broiler feedlots (free range and indoor) by quantitative PCR, and assessed their dissemination mechanisms. The results showed the prevalence of various types of ARGs in the environmental samples of the broiler feedlots including manure/litter, soil, sediment, and water samples, with the first report of five chloramphenicol resistance genes (cmlA, floR, fexA, cfr, and fexB) in broiler feedlots. Overall, chloramphenicol resistance genes and sulfonamides sul genes were more abundant than tetracyclines tet genes. The ARG abundances in the samples from indoor boiler feedlots were generally different to the free range feedlots, suggesting the importance of feeding operations in ARG dissemination. Pearson correlation analysis showed significant correlations between ARGs and mobile genetic element genes (int1 and int2), and between the different classes of ARGs themselves, revealing the roles of horizontal gene transfer and coselection for ARG dissemination in the environment. Further regression analysis revealed that fexA, sul1 and tetW could be reliable indicator genes to surrogate anthropogenic sources of ARGs in boiler feedlots (correlations of fexA, sul1 and tetW to all ARGs: R = 0.95, 0.96 and 0.86, p < 0.01). Meanwhile, significant correlations were also identified between indicator ARGs and their corresponding antibiotics. In addition, some ARGs were significantly correlated with typical metals (e.g., Cu, Zn, and As with fexA, fexB, cfr, sul1, tetW, tetO, tetS: R = 0.52-0.71) and some environmental parameters (e.g., TOC, TN, TP, NH3-N with fexA, fexB, cfr, sul1, tetW, tetO, tetQ, tetS: R = 0.53-0.87) (p < 0.01). Further redundancy analysis demonstrated that the distribution and transportation of ARGs from the boiler feedlots to the receiving environments were correlated with environmental variables. The findings highlight the contribution of some chemicals such as antibiotics and metals to the development of ARGs in broiler feedlots environments; and the observed ARG dissemination mechanism in the broiler feedlots facilitates the development of effective mitigation measures. PMID:25338275

He, Liang-Ying; Liu, You-Sheng; Su, Hao-Chang; Zhao, Jian-Liang; Liu, Shuang-Shuang; Chen, Jun; Liu, Wang-Rong; Ying, Guang-Guo

2014-11-18

425

Extended Correlation in Strongly Correlated Systems, Beyond Dynamical Cluster Approximation  

NASA Astrophysics Data System (ADS)

We present a new multi-scale approach for strongly correlated systems that combines the Dynamical Cluster Approximation and the recently introduced dual-fermion formalism. This approach employs an exact mapping from a real lattice to a DCA cluster of linear size Lc embedded in a dual fermion lattice. The short-length-scale physics is addressed by DCA cluster calculations, while the longer-length-scale physics is addressed diagrammatically using dual fermions. The bare and dressed dual fermionic Green functions scale as O(1/Lc), so perturbation theory on the dual lattice converges very quickly. E.g., the dual Fermion self-energy calculated with simple second order perturbation theory is of order O(1/Lc^3), with third order and three-body corrections down by an additional factor of O(1/Lc).

Fotso, Herbert; Yang, Shuxiang; Hafermann, Hartmut; Tam, Ka-Ming; Moreno, Juana; Pruschke, Thomas; Jarrell, Mark

2012-02-01

426

Correlation Identities, Correlation Inequalities, and Upper Bounds on Critical Temperature of Spin Systems  

NASA Astrophysics Data System (ADS)

A review on spin correlation functions identities and on rigorous correlation functions inequalities is presented for various spin models. The spin correlation identities are exactly obtained from finite cluster of spins for different models, and the rigorous spin correlation inequalities are presented for the discrete and continuous classical spin models and also for quantum spin models. Through these correlation identities and rigorous inequalities, the upper bounds on critical temperatures are obtained by the decay of the correlation function.

Santos, J. P.; Sá Barreto, F. C.

2015-02-01

427

Arousal and Anxiety Correlates of Gymnastic Performance  

ERIC Educational Resources Information Center

Tests on a women's gymnastic team to explore correlation between arousal, anxiety, and performance, revealed limited relationships between performance and arousal/anxiety measures and indicated that gymnastic ability is the best correlate of gymnastic performance. (JD)

Basler, Marilyn L.; And Others

1976-01-01

428

NOVEL TECHNIQUES IN ULTRASONIC CORRELATION SPECTROSCOPY  

E-print Network

1 NOVEL TECHNIQUES IN ULTRASONIC CORRELATION SPECTROSCOPY: Characterizing the Dynamics of Strongly this need, we have developed two ultrasonic correlation spectroscopies, Dynamic Sound Scattering (DSS) and Diffusing Acoustic Wave Spectroscopy (DAWS)1 , which exploit the dynamic information present in ultrasonic

Page, John

429

Statistical correlations of crime with arrests  

NASA Astrophysics Data System (ADS)

Regression analysis shows that the overall crime rate correlates with the overall arrest rate. Violent crime only weakly correlates with the violent arrest rate, but strongly correlates with the property arrest rate. Contrary to common impressions, increasing arrest rates do not significantly increase loading on incarceration facilities.

Kuelling, Albert C.

1997-01-01

430

Scale evolution of double parton correlations  

E-print Network

We review the effect of scale evolution on a number of different correlations in double parton scattering (DPS). The strength of the correlations generally decreases with the scale but at a rate which greatly varies between different types. Through studies of the evolution, an understanding of which correlations can be of experimental relevance in different processes and kinematical regions is obtained.

Tomas Kasemets

2014-11-17

431

Functional Multiple-Set Canonical Correlation Analysis  

ERIC Educational Resources Information Center

We propose functional multiple-set canonical correlation analysis for exploring associations among multiple sets of functions. The proposed method includes functional canonical correlation analysis as a special case when only two sets of functions are considered. As in classical multiple-set canonical correlation analysis, computationally, the…

Hwang, Heungsun; Jung, Kwanghee; Takane, Yoshio; Woodward, Todd S.

2012-01-01

432

Correlations in electronic and atomic fluids  

SciTech Connect

This book covers the proceedings of a conference on Correlations in Electronic and Atomic Fluids topics include: field effects in fermi systems, dynamic electron correlations by interpolation, neutrinos, the density functional theory for superconductors, superconducting correlations in high Tc systems, and the nature of phonons and isotope effect in Ba{sub 1{minus}x}K{sub x}BiO{sub 3}.

Jena, P. (Virginia Commonwealth Univ., Richmond, VA (United States)); Kalia, R.; Vashishta, P. (Argonne National Lab., IL (United States)); Tosi, M.P. (Trieste Univ. (Italy))

1990-01-01

433

Long range correlations in e + e - annihilation?  

Microsoft Academic Search

We calculate long range multiplicity correlations in e + e - annihilation. Perturbative, probabilistic models predict vanishing multiplicity correlations between two opposite jets, in contrast to the results for non-perturbative models. The former still lead to strong long range correlations within one jet.

J. H. Kühn; H. Schneider

1981-01-01

434

Kalman Filtering in Correlated Losses Sachin Adlakha  

E-print Network

Kalman Filtering in Correlated Losses Sachin Adlakha Department of Electrical Engineering Stanford in presence of correlated losses using a Kalman Filter . This scenario arises in performing vehicle tracking for the Kalman estimator to lose some observations. We study the behavior of Kalman filter in such correlated

Adlakha, Sachin

435

Quark Correlations and Single-Spin Asymmetries  

E-print Network

Quark Correlations and Single-Spin Asymmetries Matthias Burkardt burkardt@nmsu.edu New Mexico State University Las Cruces, NM, 88003, U.S.A. Quark Correlations and Single-Spin Asymmetries ­ p.1 Implications for nucleon structure Summary Quark Correlations and Single-Spin Asymmetries ­ p.2/38 #12;What

436

Universal measurement of quantum correlations of radiation  

E-print Network

A measurement technique is proposed which, in principle, allows one to observe the general space-time correlation properties of a quantized radiation field. Our method, called balanced homodyne correlation measurement, unifies the advantages of balanced homodyne detection with those of homodyne correlation measurements.

E. Shchukin; W. Vogel

2006-05-16

437

Nonclassical correlation properties of radiation fields  

E-print Network

A full characterization of nonclassical space-time dependent correlations of radiation is formulated in terms of normally and time-ordered field correlation functions. It describes not only the properties of initially prepared multimode radiation fields, but also the dynamics of radiation sources. Some of these correlation effects occur in the resonance fluorescence of a single two-level atom.

Werner Vogel

2008-01-12

438

An 18 million year record of vegetation and climate change in northwestern Canada and Alaska: Tectonic and global climatic correlates  

USGS Publications Warehouse

We reconstruct long-term vegetation/paleoclimatic trends, spanning the last 18 million years, in Alaska. Yukon and far western Northwest Territories. Twenty-one average percentage spectra for pollen and spores are assembled from eight surface/subsurface sections. The sections are dated independently or by correlation. Pollen and spore ratios indicate the direction of change in vegetation and climatic parameters growing season temperature (T(est)), tree canopy density (C(est)) and paludification at study sites (P(est)). A global warm peak ca. 15 Ma is shown by the abundance of thermophilous taxa, including Fagus and Quercus. A temperature decline immediately following 15 Ma parallels climatic reconstructions based on marine oxygen isotopes. Subsequent declines correlate to the Messinian event and the onset of late Pliocene Pleistocene glaciation. After 7 Ma herbs and shrubs become more important elements of the palynological assemblages, suggesting a more continental, colder/drier climate. However, a late Pliocene warm interval is evident. Vegetation/climatic changes during the early to late Miocene show synchrony with, and are most economically attributable to, global events. After 7 Ma, vegetation/climate change is attributed primarily to latest Miocene-to-Pleistocene uplift of the Alaska Range and St. Elias Mrs. The continuing influence of global climatic patterns is shown in the late Pliocene warm interval, despite uplift to the south. The opening of the Bering Strait ca. 3 Ma may have moderated the climate in the study area.

White, J.M.; Ager, T.A.; Adam, D.P.; Leopold, E.B.; Liu, G.; Jette, H.; Schweger, C.E.

1997-01-01

439

Scalable correlated electronic structure theory  

NASA Astrophysics Data System (ADS)

The approach taken in Ames to advance high-level electronic structure theory has been a combination of the development and implementation of new and novel methods with the continuing development of strategies to optimize scalable computing. This work summarizes advances on both fronts. Several new methods have been implemented under the Distributed Data Interface (DDI), most recently including analytic Hessians for both Hatree- Fock and CASSCF (complete active space self-consistent field) wavefunctions, gradients for restricted open shell second order perturbation theory, and the fragment molecular orbital method (FMO). Exciting new method developments include the FMO method and the CEEIS (Correlation Energy Extrapolation by Intrinsic Scaling) method for efficiently approaching the exact energy for atomic and molecular systems.

Gordon, Mark S.; Ruedenberg, Klaus; Schmidt, Michael W.; Bytautas, Laimis; Dudley, Timothy J.; Nagata, Takeshi; Olson, Ryan; Varganov, Sergey

2006-09-01

440

The Neural Correlates of Race  

PubMed Central

Behavioral analyses are a natural choice for understanding the wide-ranging behavioral consequences of racial stereotyping and prejudice. However, neuroimaging and electrophysiological research has recently considered the neural mechanisms that underlie racial categorization and the activation and application of racial stereotypes and prejudice, revealing exciting new insights. Work reviewed here points to the importance of neural structures previously associated with face processing, semantic knowledge activation, evaluation, and self-regulatory behavioral control, allowing for the specification of a neural model of race processing. We show how research on the neural correlates of race can serve to link otherwise disparate lines of evidence on the neural underpinnings of a broad array of social-cognitive phenomena, and consider implications for effecting change in race relations. PMID:19896410

Ito, Tiffany A.; Bartholow, Bruce D.

2009-01-01

441

QCD Correlators at Large NC  

E-print Network

This talk explores the spin--1 correlators up to O(alpha_s) through a large NC resonance theory. The phenomenological analyses of this kind must take these corrections into account since they produce a larger impact than the first OPE condensates. It is also necessary to separate low and high energy regimes; fixing the parameters of the lightest multiplets through perturbative QCD arguments is unfair and introduces errors in the determination of the condensates and resonance parameters. This separation of regimes improves our understanding of the Minimal Hadronical Approximation. The study at O(alpha_s) already allows discerning between different hadronical models, where the Regge-like mass spectrum shows the best agreement to phenomenology.

J. J. Sanz-Cillero

2005-10-12

442

Neural correlates of face detection.  

PubMed

Although face detection likely played an essential adaptive role in our evolutionary past and in contemporary social interactions, there have been few rigorous studies investigating its neural correlates. MJH, a prosopagnosic with bilateral lesions to the ventral temporal-occipital cortices encompassing the posterior face areas (fusiform and occipital face areas), expresses no subjective difficulty in face detection, suggesting that these posterior face areas do not mediate face detection exclusively. Despite his normal contrast sensitivity and visual acuity in foveal vision, the present study nevertheless revealed significant face detection deficits in MJH. Compared with controls, MJH showed a lower tolerance to noise in the phase spectrum for faces (vs. cars), reflected in his higher detection threshold for faces. MJH's lesions in bilateral occipito-temporal cortices thus appear to have produced a deficit not only in face individuation, but also in face detection. PMID:23365211

Xu, Xiaokun; Biederman, Irving

2014-06-01

443

Vertical velocity-CCN correlations  

NASA Astrophysics Data System (ADS)

The realization that smaller cloud droplets evaporate more readily (Xue and Feingold 2006; Jiang et al. 2002) gives rise to an anti-indirect aerosol effect (IAE); less cloudiness with pollution. The greater latent heat exchange of the greater evaporation in more polluted clouds adds TKE and buoyancy gradients that can enhance vertical velocity (W), mixing and entrainment (Zhao and Austin 2005). Stronger W can increase horizontal motions, which can further enhance droplet evaporation, which further enhances latent heat exchange and vertical motions, thus, positive feedback. This could also include latent heat released during condensation (Lee and Feingold 2010), which is more rapid for the greater surface areas of the smaller more numerous droplets. These theories imply a positive relationship between within-cloud W variations; i.e., standard deviation of W (?w) and CCN concentration (NCCN) rather than W and NCCN. This implies greater turbulence in polluted clouds, which could possibly counteract the reduction of cloudiness of anti-IAE. During two stratus cloud projects, 50 cloud penetrations in 9 MASE flights and 34 cloud penetrations in 13 POST flights, within-cloud ?w-NCCN showed correlation coefficients (R) of 0.50 and 0.39. Panel a shows similar within-cloud ?w-NCCN R in all altitude bands for 17 RICO flights in small cumulus clouds. R for W-NCCN showed similar values but only at low altitudes. Out-of-cloud ?w-NCCN showed similar high values except at the highest altitudes. Within-cloud ?w showed higher R than within-cloud W with droplet concentrations (Nc), especially at higher altitudes. Panel b for 13 ICE-T cumulus cloud flights in the same location as RICO but during the opposite season, however, showed ?w and W uncorrelated with NCCN at all altitudes; and W and ?w correlated with Nc only at the highest altitudes. On the other hand, out-of-cloud ?w was correlated with NCCN at all altitudes with R similar to the corresponding R of the other projects. Overall these results are consistent with the theories noted above. Supported by NSF AGS-1035230 and DOE SC0009162. Jiang, H., G. Feingold, and W.R. Cotton, 2002: J. Geophys. Res, 107, D24, 4813. Lee, S.-S., and G. Feingold, 2010: Geophys. Res. Lett., 37, L23806. Xue, H., and G. Feingold, 2006: J. Atmos. Sci., 63, 1605-1622. Zhao, M., and P.H. Austin, 2005: J. Atmos. Sci., 62, 1291-1310. Fig. Correlation coefficients (R) between mean and standard deviations of vertical velocity (W; ?w within and outside of clouds) with CCN concentrations at 1% supersaturation (N1%) measured below the clouds and with droplet concentrations (Nc) within various altitude bands.

Hudson, J. G.; Noble, S. R.

2013-12-01

444

Extending the infrared radio correlation  

NASA Astrophysics Data System (ADS)

Co-addition of deep (rms ~ 30?Jy) 20-cm data obtained with the Australia Telescope Compact Array at the location of Spitzer Wide Field Survey (SWIRE) sources has yielded statistics of radio source counterparts to faint 24-?m sources in stacked images with rms < 1?Jy. We confirm that the infrared-radio correlation extends to f24?m = 100?Jy but with a significantly lower coefficient, f20cm = 0.039f24?m [q24 = log(f24?m/f20cm) = 1.39 +/- 0.02] than hitherto reported. We postulate that this may be due to a change in the mean q24 value ratio for objects with f24?m < 1 mJy.

Boyle, B. J.; Cornwell, T. J.; Middelberg, E.; Norris, R. P.; Appleton, P. N.; Smail, Ian

2007-04-01

445

Storm: A Framework for Biologically-Inspired Cognitive Architecture Research Douglas Pearson (douglas.pearson@threepenny.net)  

E-print Network

the development of cognitive architectures based on the structure and function of the brain. The goals to structures in the brain. We demonstrate a working implementation of the framework, where we have developed level posit direct mappings to structures and processes of neural systems in the brain. The achievements

Lewis,