Sample records for t-test pearson correlation

  1. Ghost imaging based on Pearson correlation coefficients

    NASA Astrophysics Data System (ADS)

    Yu, Wen-Kai; Yao, Xu-Ri; Liu, Xue-Feng; Li, Long-Zhen; Zhai, Guang-Jie

    2015-05-01

    Correspondence imaging is a new modality of ghost imaging, which can retrieve a positive/negative image by simple conditional averaging of the reference frames that correspond to relatively large/small values of the total intensity measured at the bucket detector. Here we propose and experimentally demonstrate a more rigorous and general approach in which a ghost image is retrieved by calculating a Pearson correlation coefficient between the bucket detector intensity and the brightness at a given pixel of the reference frames, and at the next pixel, and so on. Furthermore, we theoretically provide a statistical interpretation of these two imaging phenomena, and explain how the error depends on the sample size and what kind of distribution the error obeys. According to our analysis, the image signal-to-noise ratio can be greatly improved and the sampling number reduced by means of our new method. Project supported by the National Key Scientific Instrument and Equipment Development Project of China (Grant No. 2013YQ030595) and the National High Technology Research and Development Program of China (Grant No. 2013AA122902).

  2. t-Test for Independent or Correlated Samples

    NSDL National Science Digital Library

    Lowry, Richard, 1940-

    This page, by Richard Lowry of Vassar College, will compute the t-test for either correlated or independent samples. One may copy and paste data in or type the data in individually. Visitors will also find a link to Lowry's companion online textbook, Concepts and Applications of Inferential Statistics.

  3. Robustness of Two Formulas to Correct Pearson Correlation for Restriction of Range

    ERIC Educational Resources Information Center

    tran, minh

    2011-01-01

    Many research studies involving Pearson correlations are conducted in settings where one of the two variables has a restricted range in the sample. For example, this situation occurs when tests are used for selecting candidates for employment or university admission. Often after selection, there is interest in correlating the selection variable,…

  4. Averaging Correlations: Expected Values and Bias in Combined Pearson rs and Fisher's z Transformations

    Microsoft Academic Search

    David M. Corey; William P. Dunlap; Michael J. Burke

    1998-01-01

    R. A. Fisher's z (z'; 1958) essentially normalizes the sampling distribution of Pearson r and can thus be used to obtain an average correlation that is less affected by sampling distribution skew, suggesting a less biased statistic. Analytical formulae, however, indicate less expected bias in average r than in average z' back-converted to average rz'. In large part because of

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

    ERIC Educational Resources Information Center

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

    2010-01-01

    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…

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

    PubMed Central

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

    2014-01-01

    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

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

    ERIC Educational Resources Information Center

    Zimmerman, Donald W.

    2012-01-01

    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…

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

    ERIC Educational Resources Information Center

    Nicolich, Mark J.; Weinstein, Carol S.

    1981-01-01

    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)

  9. Variation and pearson correlation coefficients of warner-bratzler shear force measurements within broiler breast fillets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measurements of texture properties related to tenderness at different locations within deboned broiler breast fillets have been used to validate techniques for texture analysis and establish correlations between different texture evaluation methods. However, it has been demonstrated that meat text...

  10. Effects of Coarse Grouping and Skewed Marginal Distributions on the Pearson Product Moment Correlation Coefficient

    ERIC Educational Resources Information Center

    Wylie, Peter B.

    1976-01-01

    Twelve non-normal bivariate distributions were constructed to investigate the effects which coarsley grouped, skewed marginal distributions have on the correlation coefficient and the accuracy of current methods of correction for grouping. (Author/RC)

  11. Student's t-Tests

    NSDL National Science Digital Library

    Kirkman, Thomas

    This page gives a short background on Student's t-test and provides three t-test calculators. Two perform t-tests for independent groups and one performs t-tests for matched pairs. Users type in individual data points or copy and paste the entire data set. Some examples are given for demonstration.

  12. Biochemical abnormalities in Pearson syndrome.

    PubMed

    Crippa, Beatrice Letizia; Leon, Eyby; Calhoun, Amy; Lowichik, Amy; Pasquali, Marzia; Longo, Nicola

    2015-03-01

    Pearson marrow-pancreas syndrome is a multisystem mitochondrial disorder characterized by bone marrow failure and pancreatic insufficiency. Children who survive the severe bone marrow dysfunction in childhood develop Kearns-Sayre syndrome later in life. Here we report on four new cases with this condition and define their biochemical abnormalities. Three out of four patients presented with failure to thrive, with most of them having normal development and head size. All patients had evidence of bone marrow involvement that spontaneously improved in three out of four patients. Unique findings in our patients were acute pancreatitis (one out of four), renal Fanconi syndrome (present in all patients, but symptomatic only in one), and an unusual organic aciduria with 3-hydroxyisobutyric aciduria in one patient. Biochemical analysis indicated low levels of plasma citrulline and arginine, despite low-normal ammonia levels. Regression analysis indicated a significant correlation between each intermediate of the urea cycle and the next, except between ornithine and citrulline. This suggested that the reaction catalyzed by ornithine transcarbamylase (that converts ornithine to citrulline) might not be very efficient in patients with Pearson syndrome. In view of low-normal ammonia levels, we hypothesize that ammonia and carbamylphosphate could be diverted from the urea cycle to the synthesis of nucleotides in patients with Pearson syndrome and possibly other mitochondrial disorders. PMID:25691415

  13. IBMFS - Pearson Syndrome

    Cancer.gov

    Patients with Pearson Syndrome may have poor food absorption (malabsorption) and low white blood cell counts (neutropenia). Low red cell counts (anemia) can be a major problem, and low platelet counts (thrombocytopenia) can also occur. Symptoms are often present in infancy. Liver and kidney disease usually develop. Examination of the bone marrow under the microscope reveals characteristic holes ("vacuoles") in many cells.

  14. Copyright 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Conditionals

    E-print Network

    Yang, Zijiang "James"

    Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Chapter 5 Part 1 Conditionals and Loops #12;Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 5-2 #12;Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 5-3 #12;Copyright

  15. Parental Socio-Economic Status as Correlate of Child Labour in Ile-Ife, Nigeria

    ERIC Educational Resources Information Center

    Elegbeleye, O. S.; Olasupo, M. O.

    2012-01-01

    This study investigated the relationship between parental socio-economic status and child labour practices in Ile-Ife, Nigeria. The study employed survey method to gather data from 200 parents which constituted the study population. Pearson Product Moment Correlation and t-test statistics were used for the data analyses. The outcome of the study…

  16. Single Sample t-Test

    NSDL National Science Digital Library

    Lowry, Richard, 1940-

    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.

  17. RESIDENTS OF OLD WILMINGTON DOLLY PEARSON

    E-print Network

    Pawlik, Joseph

    RESIDENTS OF OLD WILMINGTON DOLLY PEARSON BEAUTIFUL GARDEN AWARD 2013 NOMINATION FORM This annual award was established to honor ROW founding member Dolly Pearson on her 100th birthday (2012). Dolly will be paid to areas that can be seen from the sidewalk and street, in honor of Dolly's commitment

  18. Overview Terminology The Neyman-Pearson Lemma Simple Hypotheses

    E-print Network

    Watkins, Joseph C.

    Overview Terminology The Neyman-Pearson Lemma Topic 17 Simple Hypotheses Terminology and the Neyman-Pearson Lemma 1 / 10 #12;Overview Terminology The Neyman-Pearson Lemma Outline Overview Terminology The Neyman-Pearson Lemma 2 / 10 #12;Overview Terminology The Neyman-Pearson Lemma Overview The logic of hypothesis testing

  19. Drew Pearson's Washington Merry-Go-Round

    NSDL National Science Digital Library

    The name Drew Pearson might not be well known today to most people, but from the early 1930s until 1969, he wrote the highly influential (and controversial) syndicated column, "Washington Merry-Go-Round". The column served a muck-racking function for the highest levels of government in the United States. During his long tenure, Pearson wrote on the subject of unscrupulous public officials and became known for his flair for the dramatic. During his long career, Pearson also wrote ten books, including "U.S.A.: Second Class Power?" This excellent collection from American University brings together many of his columns from 1932 to 1969, along with a biography of Pearson and a bibliography of related works. Visitors should feel free to dive right in, and they can also browse by titles and dates.

  20. Come Celebrate With Us Eliot-Pearson's 50th Anniversary

    E-print Network

    Dennett, Daniel

    Come Celebrate With Us Eliot-Pearson's 50th Anniversary as a Department Saturday, October 25th Scarlett at 617-627-2248 #12;Greetings from Eliot-Pearson! Please join us to celebrate Eliot-Pearson's 50th

  1. Karl Pearson's meta-analysis revisited

    E-print Network

    Owen, Art B

    2009-01-01

    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 proposed. We show that Pearson's proposal is admissible. Because it is admissible, it has better power than the standard test of Fisher [Statistical Methods for Research Workers (1932) Oliver and Boyd] at some alternatives, and worse power at others. Pearson's method has the advantage when all or most of the nonzero parameters share the same sign. Pearson's test has proved useful in a genomic setting, screening for age-related genes. This paper also presents an FFT-based method for getting hard upper and lower bounds on the CDF of a sum of nonnegative random variables.

  2. NCS Pearson: Scanning the Diet History Questionnaire

    Cancer.gov

    NCS Pearson is one source of scannable DHQ forms and scanning services. See Scanning the DHQ for information regarding other sources. Any new information we know of regarding economical printing, scanning, or data entry methods will be posted on this Web site as it becomes available.

  3. Pearson and Pedagogy: Countering Co-Dependency

    ERIC Educational Resources Information Center

    Fielder, John

    2008-01-01

    Noel Pearson and Marcia Langton have both used the terms "co-dependency" and "rescuing" as part of their challenge to the rights-based focus informing Indigenous policies in Australia since the 1960s. Their premise is that the liberal/Left welfare-based agenda, for decades, has largely overlooked Indigenous responsibility. At the same time, they…

  4. The One-Sample t Test

    NSDL National Science Digital Library

    Price, Ian

    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.

  5. 2005 Pearson Education Inc., publishing as Addison-Wesley

    E-print Network

    Shirley, Yancy

    Pearson Education Inc., publishing as Addison-Wesley Eratosthenes measures Circumference of the Earth (c. 240 BC) Eratosthenes measured a value of 42,000 km (modern value 40,075 km) #12;© 2005 Pearson

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

    E-print Network

    Berdichevsky, Victor

    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

  7. How accurate is the Pearson r-from-Z approximation? A Monte Carlo simulation study.

    PubMed

    Hittner, James B; May, Kim

    2012-01-01

    The Pearson r-from-Z approximation estimates the sample correlation (as an effect size measure) from the ratio of two quantities: the standard normal deviate equivalent (Z-score) corresponding to a one-tailed p-value divided by the square root of the total (pooled) sample size. The formula has utility in meta-analytic work when reports of research contain minimal statistical information. Although simple to implement, the accuracy of the Pearson r-from-Z approximation has not been empirically evaluated. To address this omission, we performed a series of Monte Carlo simulations. Results indicated that in some cases the formula did accurately estimate the sample correlation. However, when sample size was very small (N = 10) and effect sizes were small to small-moderate (ds of 0.1 and 0.3), the Pearson r-from-Z approximation was very inaccurate. Detailed figures that provide guidance as to when the Pearson r-from-Z formula will likely yield valid inferences are presented. PMID:24836910

  8. 2015 Pearson Education, Inc. Chapter 1. Essentials of Geography

    E-print Network

    Pan, Feifei

    aspects of the universe work. · This approach is called the "scientific method." #12;© 2015 Pearson Education, Inc. The Scientific Method #12;© 2015 Pearson Education, Inc. Scientific Method theory consistent activities and human population growth as they relate to geographic science, and summarize the scientific

  9. 2005 Pearson Education Inc., publishing as Addison-Wesley

    E-print Network

    Shirley, Yancy

    © 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

  10. Chapter 12 The Dynamic Planet 2015 Pearson Education, Inc.

    E-print Network

    Pan, Feifei

    ? "Present thinking" places Earth's age at 4.6 billion years. The Moon is about 30 million years younger than the Age of Earth? #12;© 2015 Pearson Education, Inc. Radiometric Dating #12;© 2015 Pearson Education, Inc between the endogenic and exogenic systems that shape Earth, and name the driving force for each

  11. One and Two-Tailed t-Tests

    NSDL National Science Digital Library

    Stockburger, David W.

    This website, created by David W. Stockburger, provides a basic explanation with diagrams of the one and two-tailed t-tests. The page does more than simply provide explanations of the test, but it actually compares the t-tests showing their strengths and weaknesses. This is a nice presentation that is apart of a larger piece of work by the author.

  12. 3. Historic American Buildings Survey, Elmer R. Pearson, Photographer, 1968 ...

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

    3. Historic American Buildings Survey, Elmer R. Pearson, Photographer, 1968 ELEVATION, LOOKING NORTHWEST. - Shaker Centre Family, Broom Shop, East side of Oxford Road, White Water Park, Hamilton County, OH

  13. 2015 Pearson Education, Inc. Chapter 5 Global Temperatures

    E-print Network

    Pan, Feifei

    and Heat Transfer #12;© 2015 Pearson Education, Inc. · Fahrenheit (°F) ­ Ice melting point at 32°F, boiling point of water at 212ºF · Celsius (°C) ­ Ice melting point at 0°C, boiling point of water at sea level

  14. Biostatistik, WS 2013/2014 Der zwei-Stichproben-t-Test

    E-print Network

    Birkner, Matthias

    Biostatistik, WS 2013/2014 Der zwei-Stichproben-t-Test (t-Test f¨ur ungepaarte Stichproben;1 Wiederholung: Ein-Stichproben-t-Test 2 t-Test f¨ur ungepaarte Stichproben Beispiel: Backenz¨ahne von Hipparions Allgemein: ungepaarter t-Test mit Annahme gleicher Varianzen Bericht: t-Test ohne Annahme gleicher Varianz

  15. Biostatistik, WS 2010/2011 Der zwei-Stichproben-t-Test

    E-print Network

    Birkner, Matthias

    Biostatistik, WS 2010/2011 Der zwei-Stichproben-t-Test (t-Test f¨ur ungepaarte Stichproben;1 Wiederholung: Ein-Stichproben-t-Test 2 t-Test f¨ur ungepaarte Stichproben Beispiel: Backenz¨ahne von Hipparions Allgemein: ungepaarter t-Test mit Annahme gleicher Varianzen Bericht: t-Test ohne Annahme gleicher Varianz

  16. A Null Model for Pearson Coexpression Networks

    PubMed Central

    Gobbi, Andrea; Jurman, Giuseppe

    2015-01-01

    Gene coexpression networks inferred by correlation from high-throughput profiling such as microarray data represent simple but effective structures for discovering and interpreting linear gene relationships. In recent years, several approaches have been proposed to tackle the problem of deciding when the resulting correlation values are statistically significant. This is most crucial when the number of samples is small, yielding a non-negligible chance that even high correlation values are due to random effects. Here we introduce a novel hard thresholding solution based on the assumption that a coexpression network inferred by randomly generated data is expected to be empty. The threshold is theoretically derived by means of an analytic approach and, as a deterministic independent null model, it depends only on the dimensions of the starting data matrix, with assumptions on the skewness of the data distribution compatible with the structure of gene expression levels data. We show, on synthetic and array datasets, that the proposed threshold is effective in eliminating all false positive links, with an offsetting cost in terms of false negative detected edges. PMID:26030917

  17. Karl Pearson and eugenics: personal opinions and scientific rigor.

    PubMed

    Delzell, Darcie A P; Poliak, Cathy D

    2013-09-01

    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

  18. MaxEnt alternatives to pearson family distributions

    NASA Astrophysics Data System (ADS)

    Stokes, Barrie J.

    2012-05-01

    In a previous MaxEnt conference [11] a method of obtaining MaxEnt univariate distributions under a variety of constraints was presented. The Mathematica function Interpolation[], normally used with numerical data, can also process "semi-symbolic" data, and Lagrange Multiplier equations were solved for a set of symbolic ordinates describing the required MaxEnt probability density function. We apply a more developed version of this approach to finding MaxEnt distributions having prescribed ?1 and ?2 values, and compare the entropy of the MaxEnt distribution to that of the Pearson family distribution having the same ?1 and ?2. These MaxEnt distributions do have, in general, greater entropy than the related Pearson distribution. In accordance with Jaynes' Maximum Entropy Principle, these MaxEnt distributions are thus to be preferred to the corresponding Pearson distributions as priors in Bayes' Theorem.

  19. THERMAL TRANSPORT IN SELF-ASSEMBLED NANOSTRUCTURES IAN PEARSON BLITZ

    E-print Network

    Braun, Paul

    THERMAL TRANSPORT IN SELF-ASSEMBLED NANOSTRUCTURES BY IAN PEARSON BLITZ THESIS Submitted in partial Understanding of phonon mediated thermal transport properties in nanostructured materials is essential of the thermal transport properties of model organic- inorganic, nanoscopically layered systems for the purpose

  20. 2005 Pearson Education South Asia Pte Ltd Applied Fluid Mechanics

    E-print Network

    Leu, Tzong-Shyng "Jeremy"

    . Class II Systems 5. Class III Systems 6. Pipeline Design for Structural Integrity 11. Series Pipeline Sections 10.Minor Losses 11.Series Pipeline Systems 12.Parallel Pipeline Systems 13.Pump Selection and the Flow of Gases 19.Flow of Air in Ducts 11. Series Pipeline System ©2005 Pearson Education South Asia Pte

  1. 2005 Pearson Education Inc., publishing as Addison-Wesley

    E-print Network

    Shirley, Yancy

    5 The Moon, Our Constant Companion >the Moon's orbit around the Earth #12;© 2005 Pearson Education > the wobbling of Earth's axis 5 The Moon, Our Constant Companion >the Moon's orbit around the Earth 6., publishing as Addison-Wesley France: Cave paintings from 18,000 B.C. may suggest knowledge of lunar phases

  2. 2005 Pearson Education Inc., publishing as Addison-Wesley

    E-print Network

    Shirley, Yancy

    © 2005 Pearson Education Inc., publishing as Addison-Wesley The Big Bang Theory & Expansion breath you take: the big bang is all around us. It is a theory, but a theory with a web of evidence to support it. The theory is mute about the cause of the cause. Status of the Big Bang #12;#12;© 2005

  3. 2005 Pearson Education Inc., publishing as Addison-Wesley

    E-print Network

    Shirley, Yancy

    © 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

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

    PubMed

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

    2014-01-01

    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

  5. 2005 Pearson Education Inc., publishing as Addison-Wesley

    E-print Network

    Shirley, Yancy

    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

  6. correlation Mathematical

    E-print Network

    Mosegaard, Klaus

    and correlation Stimulus p(t), T images 1 ! t ! T . Signal f(t; x; y; z) measured in (x; y; z). Filter hw (t Coefficients Convolution of the stimulus: r w (t) = +1 X ø=0 p(t \\Gamma ø)hw (ø) Un­normalised signal obtained from stan­ dard correlation analysis (or equivalent t­test). Delay =) underestimates

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

    E-print Network

    Berdichevsky, Victor

    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

  8. Copyright 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Nature of Life

    E-print Network

    Shirley, Yancy

    Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Nature of Life ·Some properties of life #12;Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Life Displays Order #12;Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Life Uses Energy #12

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

    E-print Network

    Cinabro, David

    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

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

    E-print Network

    Berdichevsky, Victor

    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

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

    E-print Network

    Berdichevsky, Victor

    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

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

    E-print Network

    Berdichevsky, Victor

    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

  13. Correlation

    NSDL National Science Digital Library

    Anderson-Cook, C.

    The applets, created by Virginia Tech's Department of Statistics, allow you to see how different bivariate data look under different correlation structures. The "Movie" applet either creates data for a particular correlation or animates a multitude data sets ranging correlations from -1 to 1. The "Creation" applet allows the user to create a data set by adding or deleting points from the screen.

  14. SALD 18A: JMP examples for one-sample t-test

    E-print Network

    Morgan, Stephen L.

    SALD 18A: JMP examples for one-sample t-test #12;Introduction Notes #12;DO NOT COPY Copyright calculation in JMP To perform a one-sample t-test, select from the data table main menu Analyze 18A-8 To perform a one-sample t-test in JMP, first perform a distribution analysis Under Select

  15. rspb.royalsocietypublishing.org Cite this article: Fagan WF, Pearson YE,

    E-print Network

    Goldberg, Emma

    rspb.royalsocietypublishing.org Research Cite this article: Fagan WF, Pearson YE, Larsen EA, Lynch, species conservation Author for correspondence: William F. Fagan e-mail: bfagan@umd.edu These authors of the maximum per capita rate of population growth William F. Fagan1,, Yanthe E. Pearson1,,, Elise A. Larsen1

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

    E-print Network

    Cinabro, David

    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

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

    E-print Network

    Berdichevsky, Victor

    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

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

    E-print Network

    Berdichevsky, Victor

    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

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

    E-print Network

    Berdichevsky, Victor

    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

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

    E-print Network

    Berdichevsky, Victor

    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

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

    SciTech Connect

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

    1994-09-01

    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.

  2. Psychological Statistics: Correlation

    NSDL National Science Digital Library

    Plonsky, Mark

    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.

  3. Pearson’s correlations between moisture content, drip loss, expressible fluid and salt-induced water gain of broiler pectoralis major muscle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Moisture content, drip loss, expressible fluid, and % salt-induced water gain are widely used to estimate water states and water-holding capacity of raw meat. However, the relationships between these four measurements of broiler pectoralis (p.) major muscle describe are not well described. The objec...

  4. Using a Nonparametric Bootstrap to Obtain a Confidence Interval for Pearson’s r with Cluster Randomized Data: A Case Study

    PubMed Central

    Elek, Elvira; Kulis, Stephen; Marsiglia, Flavio

    2009-01-01

    A nonparametric bootstrap was used to obtain an interval estimate of Pearson’s r, and test the null hypothesis that there was no association between 5th grade students’ positive substance use expectancies and their intentions to not use substances. The students were participating in a substance use prevention program in which the unit of randomization was a public middle school. The bootstrap estimate indicated that expectancies explained 21% of the variability in students’ intentions (r = 0.46, 95% CI = [0.40, 0.50]). This case study illustrates the use of a nonparametric bootstrap with cluster randomized data and the danger posed if outliers are not identified and addressed. Editors’ Strategic Implications: Prevention researchers will benefit from the authors’ detailed description of this nonparametric bootstrap approach for cluster randomized data and their thoughtful discussion of the potential impact of cluster sizes and outliers. PMID:19685290

  5. Correlation-aided support vector regression for forex time series prediction

    Microsoft Academic Search

    Shaoning Pang; Lei Song; Nik Kasabov

    Market is often found behaving surprisingly similar to history, which implies that correlation exists significant for market\\u000a trend analysis. In the context of Forex market analysis, this paper proposes a correlation-aided support vector regression\\u000a (cSVR) for time series application, where correlation data are extracted through a graphical channel correlation analysis,\\u000a compensated by a parameterized Pearson’s correlation to exclude noise meanwhile

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

    PubMed

    Pence, Charles H

    2011-12-01

    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

  7. Nonlinear FIR Filter Clones R.K. Pearson, M. Gabbouj, and J. Astola

    E-print Network

    Gabbouj, Moncef

    Nonlinear FIR Filter Clones R.K. Pearson, M. Gabbouj, and J. Astola Tampere International Center- cept of a clone from universal algebra, generalizing the FIR-median hybrid (FMH) filter construction that are preserved under the clone interconnection strategy. 1 Introduction An important idea in many engineering

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

    ERIC Educational Resources Information Center

    Pae, Hye K.

    2012-01-01

    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'…

  9. Philosophy of Science Association On After-Trial Criticisms of Neyman-Pearson Theory of Statistics

    E-print Network

    Mayo, Deborah

    Philosophy of Science Association On After-Trial Criticisms of Neyman-Pearson Theory of Statistics Author(s): Deborah G. Mayo Source: PSA: Proceedings of the Biennial Meeting of the Philosophy of Science of Chicago Press on behalf of the Philosophy of Science Association Stable URL: http

  10. Children with autism do not overimitate L. Marsh, A. Pearson, D. Ropar & A. Hamilton

    E-print Network

    Hamilton, Antonia

    Children with autism do not overimitate L. Marsh, A. Pearson, D. Ropar & A. Hamilton School object, typically developing (TD) children faithfully copy both necessary and visibly unnecessary actions to be causally transparent in their mechanism, young children's causal reasoning about novel objects is unclear

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

    E-print Network

    Cinabro, David

    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

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

    E-print Network

    Cinabro, David

    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

  13. Correlation Between Intrasac Pressure Measurements of a Pressure Sensor and an Angiographic Catheter During Endovascular Repair of Abdominal Aortic Aneurysm

    PubMed Central

    Silveira, Pierre Galvagni; Miller, Christopher William Teixeira; Mendes, Rafael Freygang; Galego, Gilberto Nascimento

    2008-01-01

    PURPOSE To establish a correlation between intrasac pressure measurements of a pressure sensor and an angiographic catheter placed in the same aneurysm sac before and after its exclusion by an endoprosthesis. METHODS Patients who underwent endovascular abdominal aortic aneurysm repair and received an EndoSureTM wireless pressure sensor implant between March 19 and December 11, 2004 were enrolled in the study. Simultaneous readings of systolic, diastolic, mean, and pulse pressure within the aneurysm sac were obtained from the catheter and the sensor, both before and after sac exclusion by the endoprosthesis (Readings 1 and 2, respectively). Intrasac pressure measurements were compared using Pearson’s correlation and Student’s t test. Statistical significance was set at p<0.05. RESULTS Twenty-five patients had the pressure sensor implanted, with simultaneous readings (i.e., recorded by both devices) obtained in 19 patients for Reading 1 and in 10 patients for Reading 2. There was a statistically significant correlation for all pressure variables during both readings, with p<0.01 for all except the pulse pressure in Reading 1 (p<0.05). Statistical significance of pressure variations before and after abdominal aortic aneurysm exclusion was coincident between the sensor and catheter for diastolic (p>0.05), mean (p>0.05), and pulse (p<0.01) pressures; the sole disagreement was observed for systolic pressure, which varied, on average, 31.23 mmHg by the catheter (p<0.05) and 22 mmHg (p>0.05) by the sensor. CONCLUSION The excellent agreement between intrasac pressure readings recorded by the catheter and the sensor justifies use of the latter for detection of post-exclusion abdominal aortic aneurysm pressurization. PMID:18297208

  14. A Spreadsheet Tool for Learning the Multiple Regression F-Test, T-Tests, and Multicollinearity

    ERIC Educational Resources Information Center

    Martin, David

    2008-01-01

    This note presents a spreadsheet tool that allows teachers the opportunity to guide students towards answering on their own questions related to the multiple regression F-test, the t-tests, and multicollinearity. The note demonstrates approaches for using the spreadsheet that might be appropriate for three different levels of statistics classes,…

  15. Chapter 10: Hypothesis Testing using t-tests: Normal Distributions with unknown variance

    E-print Network

    Collins, Sean

    Chapter 10: Hypothesis Testing using t-tests: Normal Distributions with unknown variance Sean assume that the data come from a normal distribution with unknown mean µ and unknown variance 2 are independent observations from N(µ, 2) with µ and 2 unknown. We define T = ¯X-µ s/ n The distribution

  16. Robust parametric bootstrap test with MOM estimator: An alternative to independent sample t-test

    NASA Astrophysics Data System (ADS)

    Harun, Nurul Hanis; Yusof, Zahayu Md

    2014-12-01

    Normality and homogeneity are two major assumptions that need to be fulfilled when using independent sample t-test. However, not all data encompassed with these assumptions. Consequently, the result produced by independent sample t-test becomes invalid. Therefore, the alternative is to use robust statistical procedure in handling the problems of nonnormality and variances heterogeneity. This study proposed to use Parametric Bootstrap test with popular robust estimators, MADn and Tn which empirically determines the amount of trimming. The Type I error rates produced by each procedure were examined and compared with classical parametric test and nonparametric test namely independent sample t-test and Mann Whitney test, respectively. 5000 simulated data sets are used in this study in order to generate the Type I error for each procedure. The findings of this study indicate that the Parametric Bootstrap test with MADn and Tn produces the best Type I error control compared to the independent sample t-test and the Mann Whitney test under nonnormal distribution, heterogeneous variances and unbalanced design. Then, the performance of each procedure was demonstrated using real data.

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

    ERIC Educational Resources Information Center

    Brehm, Michael A.; And Others

    1996-01-01

    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)

  18. 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

    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

    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

  19. A Comparison of Six Robust Correlation Estimators.

    ERIC Educational Resources Information Center

    Baranowski, B. Bonnie; Halperin, Silas

    A Monte Carlo investigation of six robust correlation estimators was conducted for data from distributions with longer than Gaussian tails: a bisquare coefficient, the Tukey correlation, the standardized sums and differences, a biweight standardized sums and differences, the transformed Spearman's rho and a bivariate trimmed Pearson. Evaluation of…

  20. Is the Pearson r[squared] Biased, and if So, What Is the Best Correction Formula?

    ERIC Educational Resources Information Center

    Wang, Zhongmiao; Thompson, Bruce

    2007-01-01

    In this study the authors investigated the use of 5 (i.e., Claudy, Ezekiel, Olkin-Pratt, Pratt, and Smith) R[squared] correction formulas with the Pearson r[squared]. The authors estimated adjustment bias and precision under 6 x 3 x 6 conditions (i.e., population [rho] values of 0.0, 0.1, 0.3, 0.5, 0.7, and 0.9; population shapes normal, skewness…

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

    ERIC Educational Resources Information Center

    Skidmore, Susan Troncoso; Thompson, Bruce

    2011-01-01

    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;…

  2. Wanted: guidelines for reporting correlations

    NSDL National Science Digital Library

    Bartholomew Kay (University of Auckland Sport and Exercise Science)

    2009-06-01

    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.

  3. Risk stratification with a point-of-care cardiac troponin T test in acute myocardial infarction

    Microsoft Academic Search

    E. Magnus Ohman; Paul W Armstrong; Harvey D White; Christopher B Granger; Robert G Wilcox; W. Douglas Weaver; W. Brian Gibler; Amanda L Stebbins; Cresha Cianciolo; Robert M Califf; Eric J Topol

    1999-01-01

    Troponin T has been used successfully to risk stratify patients with acute coronary syndromes, but the utility of this approach using a rapid bedside assay in patients undergoing thrombolysis for ST-segment elevation acute myocardial infarction has not been assessed in a large population. We assessed whether a point-of-care, qualitative troponin T test at enrollment could independently risk-stratify patients randomized to

  4. Two-Sample t-Test for Equal Means (Engineering Statistics Handbook)

    NSDL National Science Digital Library

    Filliben, James

    Gives textbook-like explanation with some real-life data to compute a t-test and determine if two population means are equal. Also has some links for case studies and a web-based program called Dataplot. There is a printer-friendly version on the main homepage (see source). Overall, this is a great resource for anyone interested in either engineering or mathematics.

  5. Section 5-4: Paired t-Test Math/Stat 370: Engineering Statistics

    E-print Network

    Li, Haijun

    Section 5-4: Paired t-Test Math/Stat 370: Engineering Statistics Haijun Li lih@math.wsu.edu Department of Mathematics Washington State University Week 10 Haijun Li Math/Stat 370: Engineering Statistics Population 2 Sample 1: x11, x12,..., x1n1 Sample 2: x21, x22,..., x2n2 1 2 2 2 Haijun Li Math/Stat 370

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

    NSDL National Science Digital Library

    Fiona McElduff (University College London)

    2010-09-01

    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.

  7. The Pearson walk with shrinking steps in two dimensions This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-print Network

    Redner, Sidney

    The Pearson walk with shrinking steps in two dimensions This article has been downloaded from The Pearson walk with shrinking steps in two dimensions C A Serino and S Redner Center for Polymer Studies.iop.org/JSTAT/2010/P01006 doi:10.1088/1742-5468/2010/01/P01006 Abstract. We study the shrinking Pearson random walk

  8. Genome-scale cluster analysis of replicated microarrays using shrinkage correlation coefficient

    Microsoft Academic Search

    Jianchao Yao; Chunqi Chang; Mari L. Salmi; Yeung Sam Hung; Ann E. Loraine; Stanley J. Roux

    2008-01-01

    BACKGROUND: Currently, clustering with some form of correlation coefficient as the gene similarity metric has become a popular method for profiling genomic data. The Pearson correlation coefficient and the standard deviation (SD)-weighted correlation coefficient are the two most widely-used correlations as the similarity metrics in clustering microarray data. However, these two correlations are not optimal for analyzing replicated microarray data

  9. Mast Cells Density Positive to Tryptase Correlates with Angiogenesis in Pancreatic Ductal Adenocarcinoma Patients Having Undergone Surgery

    PubMed Central

    Sacco, Rosario; Sammarco, Giuseppe; Donato, Giuseppe; Zuccalà, Valeria; Luposella, Maria; Patruno, Rosa; Marech, Ilaria; Montemurro, Severino; Zizzo, Nicola; Gadaleta, Cosmo Damiano

    2014-01-01

    Background. Literature data suggest that cells such as mast cells (MCs), are involved in angiogenesis. MCs can stimulate angiogenesis by releasing of several proangiogenic cytokines stored in their cytoplasm. In particular MCs can release tryptase, a potent in vivo and in vitro proangiogenic factor. Nevertheless few data are available concerning the role of MCs positive to tryptase in primary pancreatic cancer angiogenesis. This study analyzed MCs and angiogenesis in primary tumour tissue from patients affected by pancreatic ductal adenocarcinoma (PDAC). Method. A series of 31 PDAC patients with stage T2-3N0-1M0 (by AJCC for Pancreas Cancer Staging 7th Edition) was selected and then underwent surgery. Tumour tissue samples were evaluated by means of immunohistochemistry and image analysis methods in terms of number of MCs positive to tryptase (MCDPT), area occupied by MCs positive to tryptase (MCAPT), microvascular density (MVD), and endothelial area (EA). The above parameters were related to each other and to the main clinicopathological features. Results. A significant correlation between MCDPT, MCAPT, MVD, and EA group was found by Pearson's t-test analysis (r ranged from 0.69 to 0.81; P value ranged from 0.001 to 0.003). No other significant correlation was found. Conclusion. Our pilot data suggest that MCs positive to tryptase may play a role in PDAC angiogenesis and they could be further evaluated as a novel tumour biomarker and as a target of antiangiogenic therapy. PMID:24995015

  10. Infiltrating Mast Cells Correlate with Angiogenesis in Bone Metastases from Gastric Cancer Patients

    PubMed Central

    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

    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

  11. Independent Samples t-Test: Chips Ahoy® vs. Supermarket Brand

    NSDL National Science Digital Library

    Whittinghill, Dex

    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 Ahoy® 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.

  12. Bootstrap power of the generalized correlation coefficient

    Microsoft Academic Search

    Reza Modarres

    1996-01-01

    We present a bootstrap Monte Carlo algorithm for computing the power function of the generalized correlation coefficient. The proposed method makes no assumptions about the form of the underlying probability distribution and may be used with observed data to approximate the power function and pilot data for sample size determination. In particular, the bootstrap power functions of the Pearson product

  13. Performance evaluation for epileptic electroencephalogram (EEG) detection by using Neyman-Pearson criteria and a support vector machine

    NASA Astrophysics Data System (ADS)

    Wang, Chun-mei; Zhang, Chong-ming; Zou, Jun-zhong; Zhang, Jian

    2012-02-01

    The diagnosis of several neurological disorders is based on the detection of typical pathological patterns in electroencephalograms (EEGs). This is a time-consuming task requiring significant training and experience. A lot of effort has been devoted to developing automatic detection techniques which might help not only in accelerating this process but also in avoiding the disagreement among readers of the same record. In this work, Neyman-Pearson criteria and a support vector machine (SVM) are applied for detecting an epileptic EEG. Decision making is performed in two stages: feature extraction by computing the wavelet coefficients and the approximate entropy (ApEn) and detection by using Neyman-Pearson criteria and an SVM. Then the detection performance of the proposed method is evaluated. Simulation results demonstrate that the wavelet coefficients and the ApEn are features that represent the EEG signals well. By comparison with Neyman-Pearson criteria, an SVM applied on these features achieved higher detection accuracies.

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

    NASA Astrophysics Data System (ADS)

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

    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.

  15. IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 57, NO. 5, MAY 2009 1655 Optimal Noise Benefits in NeymanPearson and

    E-print Network

    Kosko, Bart

    IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 57, NO. 5, MAY 2009 1655 Optimal Noise Benefits count or SNR against the variance or dispersion of the noise process. We focus first on the special case) noise benefits for Neyman­Pearson hypothesis testing and for more general in- equality

  16. A 13-Moment Two-Fluid Plasma Physics Model Based on a Pearson Type-IV Distribution Function

    E-print Network

    Shumlak, Uri

    a recursion relationship that relates higher moments to lower as well as an extended region of hyperbolicityA 13-Moment Two-Fluid Plasma Physics Model Based on a Pearson Type-IV Distribution Function Shaun Gilliam A thesis submitted in partial fulllment of the requirements for the degree of Master of Science

  17. Factors That Attenuate the Correlation Coefficient and Its Analogs.

    ERIC Educational Resources Information Center

    Dolenz, Beverly

    The correlation coefficient is an integral part of many other statistical techniques (analysis of variance, t-tests, etc.), since all analytic methods are actually correlational (G. V. Glass and K. D. Hopkins, 1984). The correlation coefficient is a statistical summary that represents the degree and direction of relationship between two variables.…

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

    ERIC Educational Resources Information Center

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

    2004-01-01

    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…

  19. Direct Estimation of Correlation as a Measure of Association Strength Using Multidimensional Item Response Models

    ERIC Educational Resources Information Center

    Wang, Wen-Chung

    2004-01-01

    The Pearson correlation is used to depict effect sizes in the context of item response theory. Amultidimensional Rasch model is used to directly estimate the correlation between latent traits. Monte Carlo simulations were conducted to investigate whether the population correlation could be accurately estimated and whether the bootstrap method…

  20. A New Methodology of Spatial Cross-Correlation Analysis

    PubMed Central

    Chen, Yanguang

    2015-01-01

    Spatial correlation modeling comprises both spatial autocorrelation and spatial cross-correlation processes. The spatial autocorrelation theory has been well-developed. It is necessary to advance the method of spatial cross-correlation analysis to supplement the autocorrelation analysis. This paper presents a set of models and analytical procedures for spatial cross-correlation analysis. By analogy with Moran’s index newly expressed in a spatial quadratic form, a theoretical framework is derived for geographical cross-correlation modeling. First, two sets of spatial cross-correlation coefficients are defined, including a global spatial cross-correlation coefficient and local spatial cross-correlation coefficients. Second, a pair of scatterplots of spatial cross-correlation is proposed, and the plots can be used to visually reveal the causality behind spatial systems. Based on the global cross-correlation coefficient, Pearson’s correlation coefficient can be decomposed into two parts: direct correlation (partial correlation) and indirect correlation (spatial cross-correlation). As an example, the methodology is applied to the relationships between China’s urbanization and economic development to illustrate how to model spatial cross-correlation phenomena. This study is an introduction to developing the theory of spatial cross-correlation, and future geographical spatial analysis might benefit from these models and indexes. PMID:25993120

  1. Understanding Correlation: Factors that Affect the Size of r

    ERIC Educational Resources Information Center

    Goodwin, Laura D.; Leech, Nancy L.

    2006-01-01

    The authors describe and illustrate 6 factors that affect the size of a Pearson correlation: (a) the amount of variability in the data, (b) differences in the shapes of the 2 distributions, (c) lack of linearity, (d) the presence of 1 or more "outliers," (e) characteristics of the sample, and (f) measurement error. Also discussed are ways to…

  2. Malnutrition-Inflammation Score and Quality of Life in Hemodialysis Patients: Is There Any Correlation?

    PubMed Central

    Sohrabi, Zahra; Eftekhari, Mohammad Hassan; Eskandari, Mohammad Hadi; Rezaeianzadeh, Abbas; Sagheb, Mohammad Mahdi

    2015-01-01

    Background: Malnutrition, inflammation and poor quality of life are prevalent among hemodialysis (HD) patients. Health-related quality of life is an important determinant of hospitalization and mortality in HD patients. Objectives: The aim of this study was to assess the correlation between quality of life and malnutrition-inflammation status according to subjective global assessment (SGA) and malnutrition-inflammation scores (MIS) in HD patients. Patients and Methods: We randomly selected 87 of 180 stable HD patients from two HD centers. Those on hemodialysis for at least three months and with malnutrition according to the SGA scores were included in this study. They were divided into two groups of mild to moderate malnutrition (n = 39) and severe malnutrition (n = 49) based on the SGA scores. Serum levels of transferrin, albumin, blood urea nitrogen, creatinine, kt/v, body mass index and malnutrition-inflammation scores were measured in all patients. Health-related quality of life was assessed by validated short form-12 (SF-12) questionnaire for each patient. These values were compared between the two groups of patients by independent sample t-test and Mann-Whitney U test. The correlations of nutritional variables with SGA and MIS scores were determined by Pearson and Spearman correlation tests. Results: There were no differences in measured parameters between the two groups except for MIS scores. Those with severe malnutrition showed higher MIS scores. All quality of life aspects and total scores (PCS, MCS) (rather than social functioning (SF) aspect) were significantly different between the two groups, which showed lower physical and mental scores in severely-malnourished patients. Physical functioning (PF), role limitations due to physical heath (RP), general health (GH), mental health (MH), SF, role limitation due to emotional health (RE), vitality (VT) aspects and total scores (PCS and MCS) had negative significant correlations with MIS and SGA scores (All P values < 0.05). No correlation was found between MIS and SGA scores and other measured variables. Conclusions: This study focused on important effects of malnutrition and inflammation on health-related quality of life aspects, both physically and mentally in HD patients. SGA and MIS are highly correlated with quality of life in HD patients. PMID:26034747

  3. Rutgers University and Pearson have partnered to build and grow complete online degree programs. The partnership includes five key components: marketing, enrollment services and executive coaching,

    E-print Network

    Garfunkel, Eric

    offers prospective students free access to personalized online GRE prep services in order to support them participation so they can prioritize which students may need intervention. Test Prep & Career Services: Pearson

  4. A binless correlation measure reduces the variability of memory reactivation estimates

    Microsoft Academic Search

    Peter B. Kruskal; Jessica J. Stanis; Bruce L. McNaughton; Peter J. Thomas

    2007-01-01

    SUMMARY The standard procedure for measuring correlations between pairs of spike trains is to count the numbers of spikes occurring within a specified set of time intervals partitioning the continuous time line into discrete bins of width w (seconds). One then computes the Pearson correlation between pairs of the bin occupancy vectors. This method introduces a form of quantization noise,

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

    ERIC Educational Resources Information Center

    Hafdahl, Adam R.; Williams, Michelle A.

    2009-01-01

    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…

  6. Measurement of Waist and Hip Circumference with a Body Surface Scanner: Feasibility, Validity, Reliability, and Correlations with Markers of the Metabolic Syndrome

    PubMed Central

    Jaeschke, Lina; Steinbrecher, Astrid; Pischon, Tobias

    2015-01-01

    Objective Body surface scanners (BS), which visualize a 3D image of the human body, facilitate the computation of numerous body measures, including height, waist circumference (WC) and hip circumference (HC). However, limited information is available regarding validity and reliability of these automated measurements (AM) and their correlation with parameters of the Metabolic Syndrome (MetS) compared to traditional manual measurements (MM). Methods As part of a cross-sectional feasibility study, AM of WC, HC and height were assessed twice in 60 participants using a 3D BS (VitussmartXXL). Additionally, MM were taken by trained personnel according to WHO guidelines. Participants underwent an interview, bioelectrical impedance analysis, and blood pressure measurement. Blood samples were taken to determine HbA1c, HDL-cholesterol, triglycerides, and uric acid. Validity was assessed based on the agreement between AM and MM, using Bland-Altman-plots, correlation analysis, and paired t-tests. Reliability was assessed using intraclass correlation coefficients (ICC) based on two repeated AM. Further, we calculated age-adjusted Pearson correlation for AM and MM with fat mass, systolic blood pressure, HbA1c, HDL-cholesterol, triglycerides, and uric acid. Results Body measures were higher in AM compared to MM but both measurements were strongly correlated (WC, men, difference = 1.5cm, r = 0.97; women, d = 4.7cm, r = 0.96; HC, men, d = 2.3cm, r = 0.97; women, d = 3.0cm; r = 0.98). Reliability was high for all AM (nearly all ICC>0.98). Correlations of WC, HC, and the waist-to-hip ratio (WHR) with parameters of MetS were similar between AM and MM; for example the correlation of WC assessed by AM with HDL-cholesterol was r = 0.35 in men, and r = -0.48 in women, respectively whereas correlation of WC measured manually with HDL cholesterol was r = -0.41 in men, and r = -0.49 in women, respectively. Conclusions Although AM of WC, HC, and WHR are higher when compared to MM based on WHO guidelines, our data indicate good validity, excellent reliability, and similar correlations to parameters of the MetS. PMID:25749283

  7. Radar detection with the Neyman-Pearson criterion using supervised-learning-machines trained with the cross-entropy error

    NASA Astrophysics Data System (ADS)

    Jarabo-Amores, María-Pilar; la Mata-Moya, David de; Gil-Pita, Roberto; Rosa-Zurera, Manuel

    2013-12-01

    The application of supervised learning machines trained to minimize the Cross-Entropy error to radar detection is explored in this article. The detector is implemented with a learning machine that implements a discriminant function, which output is compared to a threshold selected to fix a desired probability of false alarm. The study is based on the calculation of the function the learning machine approximates to during training, and the application of a sufficient condition for a discriminant function to be used to approximate the optimum Neyman-Pearson (NP) detector. In this article, the function a supervised learning machine approximates to after being trained to minimize the Cross-Entropy error is obtained. This discriminant function can be used to implement the NP detector, which maximizes the probability of detection, maintaining the probability of false alarm below or equal to a predefined value. Some experiments about signal detection using neural networks are also presented to test the validity of the study.

  8. 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)

    Jenkins, Colleen; Jordan, Jay; Carlson, Jeff

    2007-02-01

    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.

  9. Calculating inverse cv, skew and pwm functions for pearson3, log-normal, extreme-value and log-logistic distributions

    Microsoft Academic Search

    R. W. Donaldson

    1996-01-01

    Equations are presented to calculate inverse CV, skew and PWM functions for the Pearson-3, log-normal, extreme-value and log-logistic distributions. Such inverse functions are used for moment and PWM estimates. Close numerical approximations are derived for the inverse functions that do not exist explicitly. This is intended to overcome the intractable nature of moment and PWM estimates.

  10. 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

    Cinabro, David

    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

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

    PubMed

    Zhang, Guangya; Ge, Huihua

    2013-10-01

    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

  12. No correlation between intraocular pressure and intracranial pressure.

    PubMed

    Han, Ying; McCulley, Timothy J; Horton, Jonathan C

    2008-08-01

    A recent study has reported an excellent correlation between intraocular pressure (IOP) and intracranial pressure (ICP), suggesting that measurement of IOP may serve as a noninvasive means to determine ICP. To reexamine the relation between IOP and ICP, we reviewed the medical records of all patients who underwent lumbar puncture between 1991 and 2007 in the neuro-ophthalmology clinic at the University of California San Francisco. Data for IOP and ICP were available for 55 patients. There was no correlation between IOP and ICP (Pearson correlation coefficient, r = 0.07; p = 0.59). IOP measurement is not a useful substitute for ICP measurement. PMID:18570302

  13. Correcting Four Similar Correlational Measures for Attenuation Due to Errors of Measurement in the Dependent Variable: Eta, Epsilon, Omega, and Intraclass r.

    ERIC Educational Resources Information Center

    Stanley, Julian C.; Livingston, Samuel A.

    Besides the ubiquitous Pearson product-moment r, there are a number of other measures of relationship that are attenuated by errors of measurement and for which the relationship between true measures can be estimated. Among these are the correlation ratio (eta squared), Kelley's unbiased correlation ratio (epsilon squared), Hays' omega squared,…

  14. Correlation of severity of chronic obstructive pulmonary disease with health-related quality of life and six-minute walk test in a rural hospital of central India

    PubMed Central

    Agrawal, Sachin R; Joshi, Rajnish; Jain, Ajitprasad

    2015-01-01

    Background: Chronic obstructive pulmonary disease (COPD) patients experience a progressive deterioration and disability leading to worsening of their health-related quality of life (HRQoL) and functional exercise capacity. We performed this study to identify the correlation of HRQoL assessed by St George's Respiratory Questionnaire (SGRQ) and the functional exercise capacity assessed by the six-minute walk test (6MWT) with severity of COPD defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria among spirometry-confirmed COPD patients, admitted in a tertiary care rural hospital. Materials and Methods: The study included 129 spirometry-confirmed COPD patients defined by the GOLD criteria from a tertiary care hospital in central India. They underwent HRQoL measurement using the disease-specific (SGRQ). Functional exercise capacity was measured by 6MWT, as per the American Thoracic Society (ATS) guidelines. Statistical Analysis: We analyzed the various SGRQ scores and six-minute walk distance (6MWD) percentage predicted with various stages of COPD using the Student's t-test. The Pearson's correlation coefficient (r) was used to assess the relationships between various SGRQ scores and 6MWD with FEV1 % predicted. Results: We found that COPD patients with GOLD III and IV, but not GOLD II, had significantly poor HRQoL measured by SGRQ, as compared to patients with mild COPD (GOLD I). An inverse linear relation was found between 6MWD and the severity of COPD. Correlation of FEV1 % predicted with various SGRQ scores varied from - 0.40 to - 0.53, with a maximum correlation of FEV1 % predicted with an SGRQ symptom score (- 0.53) and SGRQ total score (- 0.50). A strong positive correlation was found between 6MWD and FEV1 % predicted (0.57). Conclusions: Staging COPD according to the GOLD guidelines does correspond to important differences in the HRQoL of COPD patients having severe disease, but not for mild disease, whereas, the functional exercise capacity of COPD patients deteriorates in a linear fashion with the severity of disease assessed by the GOLD staging criteria. PMID:25983408

  15. 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

    Masci, Frank

    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

  16. Fully automated decomposition of raman spectra into individual Pearson's type VII distributions applied to biological and biomedical samples.

    PubMed

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

    2015-01-01

    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

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

    USGS Publications Warehouse

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

    2003-01-01

    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.

  18. Cost consequences of point-of-care troponin T testing in a Swedish primary health care setting

    PubMed Central

    Andersson, Agneta; Janzon, Magnus; Karlsson, Jan-Erik; Levin, Lars-Åke

    2014-01-01

    Abstract Objective. To evaluate the safety and cost-effectiveness of point-of-care troponin T testing (POCT-TnT) for the management of patients with chest pain in primary care. Design. Prospective observational study with follow-up. Setting. Three primary health care (PHC) centres using POCT-TnT and four PHC centres not using POCT-TnT in south-east Sweden. Patients. All patients ? 35 years of age, contacting one of the PHC centres for chest pain, dyspnoea on exertion, unexplained weakness and/or fatigue, with no other probable cause than cardiac, were included. Symptoms must have commenced or worsened during the previous seven days. Main outcome measures. Emergency referral rates, diagnoses of acute myocardial infarction (AMI) or unstable angina (UA), and costs were collected for 30 days after the patient sought care at the PHC centre. Results. A total of 196 patients with chest pain were included: 128 in PHC centres with POCT-TnT and 68 in PHC centres without POCT-TnT. Fewer patients from the PHC centres with POCT-TnT (n = 32, 25%) were emergently referred to hospital than from centres without POCT-TnT (n = 29, 43%; p = 0.011). Eight patients (6.2%) from PHC centres with POCT-TnT were diagnosed with AMI or UA compared with six patients (8.8%) from centres without POCT-TnT (p = 0.565). Two patients with AMI or UA were classified as missed cases from PHC centres with POCT-TnT and there were no missed cases from PHC centres without POCT-TnT. SKr290 000 was saved per missed case of AMI or UA. Conclusion. The use of POCT-TnT in primary care may be cost saving but at the expense of missed cases. PMID:25434410

  19. A new methodology of spatial cross-correlation analysis.

    PubMed

    Chen, Yanguang

    2015-01-01

    Spatial correlation modeling comprises both spatial autocorrelation and spatial cross-correlation processes. The spatial autocorrelation theory has been well-developed. It is necessary to advance the method of spatial cross-correlation analysis to supplement the autocorrelation analysis. This paper presents a set of models and analytical procedures for spatial cross-correlation analysis. By analogy with Moran's index newly expressed in a spatial quadratic form, a theoretical framework is derived for geographical cross-correlation modeling. First, two sets of spatial cross-correlation coefficients are defined, including a global spatial cross-correlation coefficient and local spatial cross-correlation coefficients. Second, a pair of scatterplots of spatial cross-correlation is proposed, and the plots can be used to visually reveal the causality behind spatial systems. Based on the global cross-correlation coefficient, Pearson's correlation coefficient can be decomposed into two parts: direct correlation (partial correlation) and indirect correlation (spatial cross-correlation). As an example, the methodology is applied to the relationships between China's urbanization and economic development to illustrate how to model spatial cross-correlation phenomena. This study is an introduction to developing the theory of spatial cross-correlation, and future geographical spatial analysis might benefit from these models and indexes. PMID:25993120

  20. Calculation of the threshold voltage of metal-oxide-semiconductor field-effect transistors with Pearson-IV channel doping profile

    Microsoft Academic Search

    D. L. Kwong; D. C. Meyers

    1984-01-01

    In this paper, a general analytical expression for the calculation of threshold voltage of an ion-implanted n-channel enhancement-mode metal-oxide-semiconductor field-effect transistor with a Pearson-IV channel dopant distribution is presented. Specifically, the threshold voltage in excess of the flat-band voltage is characterized as an explicit function of the four moments about the mean depth of the dopant distribution, namely, projected range,

  1. More accurate, calibrated bootstrap confidence intervals for correlating two autocorrelated climate time series

    NASA Astrophysics Data System (ADS)

    Olafsdottir, Kristin B.; Mudelsee, Manfred

    2013-04-01

    Estimation of the Pearson's correlation coefficient between two time series to evaluate the influences of one time depended variable on another is one of the most often used statistical method in climate sciences. Various methods are used to estimate confidence interval to support the correlation point estimate. Many of them make strong mathematical assumptions regarding distributional shape and serial correlation, which are rarely met. More robust statistical methods are needed to increase the accuracy of the confidence intervals. Bootstrap confidence intervals are estimated in the Fortran 90 program PearsonT (Mudelsee, 2003), where the main intention was to get an accurate confidence interval for correlation coefficient between two time series by taking the serial dependence of the process that generated the data into account. However, Monte Carlo experiments show that the coverage accuracy for smaller data sizes can be improved. Here we adapt the PearsonT program into a new version called PearsonT3, by calibrating the confidence interval to increase the coverage accuracy. Calibration is a bootstrap resampling technique, which basically performs a second bootstrap loop or resamples from the bootstrap resamples. It offers, like the non-calibrated bootstrap confidence intervals, robustness against the data distribution. Pairwise moving block bootstrap is used to preserve the serial correlation of both time series. The calibration is applied to standard error based bootstrap Student's t confidence intervals. The performances of the calibrated confidence intervals are examined with Monte Carlo simulations, and compared with the performances of confidence intervals without calibration, that is, PearsonT. The coverage accuracy is evidently better for the calibrated confidence intervals where the coverage error is acceptably small (i.e., within a few percentage points) already for data sizes as small as 20. One form of climate time series is output from numerical models which simulate the climate system. The method is applied to model data from the high resolution ocean model, INALT01 where the relationship between the Agulhas Leakage and the North Brazil Current is evaluated. Preliminary results show significant correlation between the two variables when there is 10 year lag between them, which is more or less the time that takes the Agulhas Leakage water to reach the North Brazil Current. Mudelsee, M., 2003. Estimating Pearson's correlation coefficient with bootstrap confidence interval from serially dependent time series. Mathematical Geology 35, 651-665.

  2. Does APO ?4 correlate with MRI changes in Alzheimer's disease?

    PubMed Central

    Doody, R; Azher, S; Haykal, H; Dunn, J; Liao, T; Schneider, L

    2000-01-01

    OBJECTIVE—To assess the relation between APO E genotype and MRI white matter changes in Alzheimer's disease. The APO ?4 allele is correlated with amyloid angiopathy and other neuropathologies in Alzheimer's disease and could be associated with white matter changes. If so, there should be a dose effect.?METHODS—104 patients with probable Alzheimer's disease (NINCDS-ADRDA criteria) in this Alzheimer's Disease Research Centre were studied. Patients received MRI and APO E genotyping by standardised protocols. Axial MRI was scored (modified Schelten's scale) for the presence and degree of white matter changes and atrophy in several regions by a neuroradiologist blinded to genotype. Total white matter and total atrophy scores were also generated. Data analysis included Pearson's correlation for regional and total imaging scores and analysis of variance (ANOVA) (or Kruskal-Wallis) and ?2 for demographic and disease related variables.?RESULTS—30 patients had no ?4, 53 patients were heterozygous, and 21 patients were homozygous. The three groups did not differ in sex distribution, age of onset, age at MRI, MMSE, clinical dementia rating, or modified Hachinski ischaemia scores. There were no significant correlations between total or regional white matter scores and APO E genotype (Pearson correlation).?CONCLUSIONS—No correlation between total or regional white matter scores and APO E genotype was found. The pathogenesis of white matter changes in Alzheimer's disease may be independent of APO E genotype.?? PMID:11032626

  3. Correlation of Zinc with Oxidative Stress Biomarkers

    PubMed Central

    Morales-Suárez-Varela, María; Llopis-González, Agustín; González-Albert, Verónica; López-Izquierdo, Raúl; González-Manzano, Isabel; Cháves, Javier; Huerta-Biosca, Vicente; Martin-Escudero, Juan C.

    2015-01-01

    Hypertension and smoking are related with oxidative stress (OS), which in turn reports on cellular aging. Zinc is an essential element involved in an individual’s physiology. The aim of this study was to evaluate the relation of zinc levels in serum and urine with OS and cellular aging and its effect on the development of hypertension. In a Spanish sample with 1500 individuals, subjects aged 20–59 years were selected, whose zinc intake levels fell within the recommended limits. These individuals were classified according to their smoking habits and hypertensive condition. A positive correlation was found (Pearson’s C = 0.639; p = 0.01) between Zn serum/urine quotient and oxidized glutathione levels (GSSG). Finally, risk of hypertension significantly increased when the GSSG levels exceeded the 75 percentile; OR = 2.80 (95%CI = 1.09–7.18) and AOR = 3.06 (95%CI = 0.96–9.71). Low zinc levels in serum were related with OS and cellular aging and were, in turn, to be a risk factor for hypertension.  PMID:25774936

  4. Can Twitter Be a Source of Information on Allergy? Correlation of Pollen Counts with Tweets Reporting Symptoms of Allergic Rhinoconjunctivitis and Names of Antihistamine Drugs

    PubMed Central

    Gesualdo, Francesco; Stilo, Giovanni; D’Ambrosio, Angelo; Carloni, Emanuela; Pandolfi, Elisabetta; Velardi, Paola; Fiocchi, Alessandro; Tozzi, Alberto E.

    2015-01-01

    Pollen forecasts are in use everywhere to inform therapeutic decisions for patients with allergic rhinoconjunctivitis (ARC). We exploited data derived from Twitter in order to identify tweets reporting a combination of symptoms consistent with a case definition of ARC and those reporting the name of an antihistamine drug. In order to increase the sensitivity of the system, we applied an algorithm aimed at automatically identifying jargon expressions related to medical terms. We compared weekly Twitter trends with National Allergy Bureau weekly pollen counts derived from US stations, and found a high correlation of the sum of the total pollen counts from each stations with tweets reporting ARC symptoms (Pearson’s correlation coefficient: 0.95) and with tweets reporting antihistamine drug names (Pearson’s correlation coefficient: 0.93). Longitude and latitude of the pollen stations affected the strength of the correlation. Twitter and other social networks may play a role in allergic disease surveillance and in signaling drug consumptions trends. PMID:26197474

  5. Correlations of temperament types, intensity of crisis at midlife with scores on a death scale.

    PubMed

    Waskel, S A; Coleman, J

    1991-06-01

    331 subjects completed the Keirsey-Bates Temperament Sorter and Dickstein's Death Scale and responded to an intensity of midlife crisis probe. Using a Pearson product-moment coefficient, weak but significant correlations were found for the introvert-sensor-thinker-judger temperament type on the Think and Anxiety subscales and the Think subscale for introvert-sensor-thinker-judger (ISTJ) temperament type. PMID:1924616

  6. Superadditive correlation

    NASA Astrophysics Data System (ADS)

    Giraud, B. G.; Heumann, John M.; Lapedes, Alan S.

    1999-05-01

    The fact that correlation does not imply causation is well known. Correlation between variables at two sites does not imply that the two sites directly interact, because, e.g., correlation between distant sites may be induced by chaining of correlation between a set of intervening, directly interacting sites. Such ``noncausal correlation'' is well understood in statistical physics: an example is long-range order in spin systems, where spins which have only short-range direct interactions, e.g., the Ising model, display correlation at a distance. It is less well recognized that such long-range ``noncausal'' correlations can in fact be stronger than the magnitude of any causal correlation induced by direct interactions. We call this phenomenon superadditive correlation (SAC). We demonstrate this counterintuitive phenomenon by explicit examples in (i) a model spin system and (ii) a model continuous variable system, where both models are such that two variables have multiple intervening pathways of indirect interaction. We apply the technique known as decimation to explain SAC as an additive, constructive interference phenomenon between the multiple pathways of indirect interaction. We also explain the effect using a definition of the collective mode describing the intervening spin variables. Finally, we show that the SAC effect is mirrored in information theory, and is true for mutual information measures in addition to correlation measures. Generic complex systems typically exhibit multiple pathways of indirect interaction, making SAC a potentially widespread phenomenon. This affects, e.g., attempts to deduce interactions by examination of correlations, as well as, e.g., hierarchical approximation methods for multivariate probability distributions, which introduce parameters based on successive orders of correlation.

  7. Dynamic correlation

    Microsoft Academic Search

    ARON J. COHEN; NICHOLAS C. HANDY

    2001-01-01

    From a knowledge of the Hartree-Fock and exact non-relativistic energies of atoms, the correlation energy Ec, as defined by Lowdin, may be calculated. For atoms this correlation is defined as dynamic correlation. The separate like-spin and unlike-spin contributions, Ec??, Ec??, may be calculated as a sum of pair energies from quantum chemistry; we have used the unrestricted Møller-Plesset second-order algorithm,

  8. Gaussian graphical modeling reveals specific lipid correlations in glioblastoma cells

    NASA Astrophysics Data System (ADS)

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

    2011-06-01

    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.

  9. EEG coherence or EEG correlation?

    PubMed

    Guevara, M A; Corsi-Cabrera, M

    1996-10-01

    In view of the widespread use of electroencephalographic correlation (r) and coherence (Coh) analyses in studying brain functional relationships, it seems important to illustrate results yielded by both methods. Although they are considered as equivalent, they show important differences. Results obtained from r and Coh were compared using: (a) 2 Hz sinusoidal signals, where phase and amplitude were artificially manipulated and, (b) Coh and r spectra obtained between each pair of derivations (C3, C4, F3, F4, T3 and T4) from wakefulness, stage 2, stage 4 and paradoxical sleep (n = 8). The following results were obtained: significant Pearson product-moment coefficients were obtained between r and Coh spectra in the range of 0.86 to 0.96 for interhemispheric and 0.60 to 0.90, for intrahemispheric paris; as a result of principal component analyses, the same three frequency bands were formed for r and Coh spectra with the exception of one single bin; similar results for r and Coh were obtained by two-way ANOVAs (physiological stages by derivations). In conclusion, as expected, a high degree of comparability between r and Coh was observed under normal physiological conditions and with the use of good quality recordings. PMID:8947780

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

    PubMed Central

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

    2015-01-01

    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. PMID:25678817

  11. Correlations between blood glucose and breath components from portable gas sensors and PTR-TOF-MS.

    PubMed

    Righettoni, M; Schmid, A; Amann, A; Pratsinis, S E

    2013-09-01

    Acetone is one of the most abundant volatile compounds in the human breath and might be important for monitoring diabetic patients. Here, a portable acetone sensor consisting of flame-made, nanostructured, Si-doped WO3 sensing films was used to analyse the end tidal fraction of the breath (collected in Tedlar bags) from eight healthy volunteers after overnight fasting (morning) and after lunch (afternoon). After breath sampling, the gaseous components were also analysed by proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS), and each person's blood glucose level was measured. The portable sensor accurately detected the presence of acetone with fast response/recovery times (<12 s) and a high signal-to-noise ratio. Statistical analysis of the relationship between the PTR-TOF-MS measurements of breath gases (e.g., acetone, isoprene, ethanol and methanol), sensor response and the blood glucose level was performed for both sampling periods. The best correlations were found after overnight fasting (morning): in particular, between blood glucose level and breath acetone (Pearson's 0.98 and Spearman's 0.93). Whereas the portable sensor response correlated best with the blood glucose (Pearson's 0.96 and Spearman's 0.81) and breath acetone (Pearson's 0.92 and Spearman's 0.69). PMID:23959908

  12. Test Review: Wagner, R. K., Torgesen, J. K., Rashotte, C. A., & Pearson, N. A., "Comprehensive Test of Phonological Processing-2nd Ed. (CTOPP-2)." Austin, Texas: Pro-Ed

    ERIC Educational Resources Information Center

    Dickens, Rachel H.; Meisinger, Elizabeth B.; Tarar, Jessica M.

    2015-01-01

    The Comprehensive Test of Phonological Processing-Second Edition (CTOPP-2; Wagner, Torgesen, Rashotte, & Pearson, 2013) is a norm-referenced test that measures phonological processing skills related to reading for individuals aged 4 to 24. According to its authors, the CTOPP-2 may be used to identify individuals who are markedly below their…

  13. Correlative Tomography

    PubMed Central

    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

    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

  14. Correlative Tomography

    NASA Astrophysics Data System (ADS)

    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

    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.

  15. Correlation of maxillary anterior tooth width and outer intercanthal distance.

    PubMed

    Eslami, Ehsan; Zadparvar, Pantea; Ansari Lari, Homeira; Mirhadian, Amir Hosein; Sadr-Eshkevari, Romina

    2015-01-01

    The selection of the correct maxillary anterior teeth to establish proper mesiodistal width in a prosthesis is one of the most crucial phases of prosthodontic treatment. The ratio of facial measurements to natural tooth width could be considered a helpful scale. The aim of this study was to explore the relationship between outer intercanthal distance (OICD) and the combined anterior width (CAW) of maxillary teeth. The CAW between the canine distal contacts and the OICD of 100 men and 100 women were measured. Pearson correlation coefficients demonstrated a positive correlation between OICD and CAW. There was no statistically significant difference between the sexes in mean difference between OICD and CAW. Within the limitations of this study, the results suggest that the OICD can be used as a fairly reliable method to determine the CAW for edentulous patients. PMID:26147166

  16. Correlation of ultrasound estimated placental volume and umbilical cord blood volume in term pregnancy

    PubMed Central

    Pannopnut, Papinwit; Kitporntheranunt, Maethaphan; Paritakul, Panwara; Kongsomboon, Kittipong

    2015-01-01

    Objective To investigate the correlation between ultrasound measured placental volume and collected umbilical cord blood (UCB) volume in term pregnancy. Material and Methods An observational cross-sectional study of term singleton pregnant women in the labor ward at Maha Chakri Sirindhorn Medical Center was conducted. Placental thickness, height, and width were measured using two-dimensional (2D) ultrasound and calculated for placental volume using the volumetric mathematic model. After the delivery of the baby, UCB was collected and measured for its volume immediately. Then, birth weight, placental weight, and the actual placental volume were analyzed. The Pearson’s correlation was used to determine the correlation between each two variables. Results A total of 35 pregnant women were eligible for the study. The mean and standard deviation of estimated placental volume and actual placental volume were 534±180 mL and 575±118 mL, respectively. The median UCB volume was 140 mL (range 98–220 mL). The UCB volume did not have a statistically significant correlation with the estimated placental volume (correlation coefficient 0.15; p=0.37). However, the UCB volume was significantly correlated with the actual placental volume (correlation coefficient 0.62; p<0.001) and birth weight (correlation coefficient 0.38; p=0.02). Conclusion The estimated placental volume by 2D ultrasound was not significantly correlated with the UCB volume. Further studies to establish the correlation between the UCB volume and the estimated placental volume using other types of placental imaging may be needed.

  17. Substance Abuse Counselors and Moral Reasoning: Hypothetical and Authentic Dilemmas

    ERIC Educational Resources Information Center

    Sias, Shari M.

    2009-01-01

    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…

  18. Assessing fMRI activation using maximum convoluted correlation C. Goutte 1 , E. Rostrup 2

    E-print Network

    Mosegaard, Klaus

    activation in functional neuroimages is to use the correlation between fMRI signal and reference stimulus or equivalently rely on a t­test between rest and activation scans. This approach has been extended to accomodateCC) For a stimulus p(t) covering T images 1 : : : T , a signal f(t; x; y; z), and a filter hw (ø) parameterised by w

  19. Inferring Correlation Networks from Genomic Survey Data

    PubMed Central

    Friedman, Jonathan; Alm, Eric J.

    2012-01-01

    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

  20. Statistical approaches for assessing the relative validity of a food-frequency questionnaire: use of correlation coefficients and the kappa statistic

    Microsoft Academic Search

    LF Masson; G MCNeill; JO Tomany; JA Simpson; HS Peace; L Wei; DA Grubb; C Bolton-Smith

    2003-01-01

    Objective: To compare different statistical methods for assessing the relative validity of a self-administered, 150-item, semi-quantitative food-frequency questionnaire (FFQ) with 4-day weighed diet records (WR). Design: Subjects completed the Scottish Collaborative Group FFQ and carried out a 4- day WR. Relative agreement between the FFQ and WR for energy-adjusted nutrient intakes was assessed by Pearson and Spearman rank correlation coefficients,

  1. Correlation between ocular perfusion pressure fluctuation and glaucoma severity.

    PubMed

    de Oliveira, Ana Paula Chaves; Kasahara, Niro

    2015-04-01

    The aim of the study is to assess the correlation between ocular perfusion pressure (OPP) fluctuation and the severity of glaucoma. Forty-three patients with primary open-angle glaucoma (POAG) were enrolled in the study. All subjects had intraocular pressure (IOP) and blood pressure measured at three time points (7:00 a.m., 1:00 p.m. and 7:00 p.m.). OPP was calculated based upon blood pressure and IOP, and OPP fluctuation was calculated as the standard deviation of the three measurements. OPP fluctuation was correlated with a structural measure (cup-to-disk ratio) and two functional measures [mean deviation (MD) and pattern standard deviation (PSD) values from automated perimetry] with the Pearson's correlation coefficient. OPP fluctuation showed statistically significant correlation with both MD (r = -0.35, P = 0.01) and PDS (r = 0.44, P = 0.00). No correlation was found between OPP fluctuation and cup-to-disk ratio (r = 0.10, P = 0.48). POAG patients with higher OPP fluctuation have greater severity of disease as measured by functional parameters. PMID:24643517

  2. The correlation between self-reported and measured height, weight, and BMI in reproductive age women.

    PubMed

    Roth, Lauren W; Allshouse, Amanda A; Lesh, Jennifer; Polotsky, Alex J; Santoro, Nanette

    2013-10-01

    This prospective, cross-sectional study of 60 women compares self-reported height, weight, and BMI with measured values. Self-reported BMI (29.0±8.37 kg/m(2)) was slightly lower than measured BMI (29.1±8.38 kg/m(2)) (p=0.4). Eighty percent of participants reported a BMI in the same category in which their BMI was measured. Pearson's correlation coefficient for height (0.96, p<0.001), weight (0.99, p<0.001), and BMI (0.99, p<0.001) were high. Reproductive age women accurately reported their height and weight. PMID:23958434

  3. The Correlation Between Self-Reported and Measured Height, Weight, and BMI in Reproductive Age Women

    PubMed Central

    Roth, Lauren W.; Allshouse, Amanda A.; Lesh, Jennifer; Polotsky, Alex J.; Santoro, Nanette

    2013-01-01

    This prospective, cross-sectional study of 60 women compares self- reported height, weight, and BMI with measured values. Self-reported BMI (29.0 ± 8.37kg/m2) was slightly lower than measured BMI (29.1 ± 8.38kg/m2) (p=0.4). Eighty percent of participants reported a BMI in the same category in which their BMI was measured. Pearson's correlation coefficient for height (0.96, p<0.001), weight (0.99, p<0.001), and BMI (0.99, p<0.001) were high. Reproductive age women accurately reported their height and weight. PMID:23958434

  4. Correlation of zinc with oxidative stress biomarkers.

    PubMed

    Morales-Suárez-Varela, María; Llopis-González, Agustín; González-Albert, Verónica; López-Izquierdo, Raúl; González-Manzano, Isabel; Cháves, Javier; Huerta-Biosca, Vicente; Martin-Escudero, Juan C

    2015-03-01

    Hypertension and smoking are related with oxidative stress (OS), which in turn reports on cellular aging. Zinc is an essential element involved in an individual's physiology. The aim of this study was to evaluate the relation of zinc levels in serum and urine with OS and cellular aging and its effect on the development of hypertension. In a Spanish sample with 1500 individuals, subjects aged 20-59 years were selected, whose zinc intake levels fell within the recommended limits. These individuals were classified according to their smoking habits and hypertensive condition. A positive correlation was found (Pearson's C=0.639; p=0.01) between Zn serum/urine quotient and oxidized glutathione levels (GSSG). Finally, risk of hypertension significantly increased when the GSSG levels exceeded the 75 percentile; OR=2.80 (95%CI=1.09-7.18) and AOR=3.06 (95%CI=0.96-9.71). Low zinc levels in serum were related with OS and cellular aging and were, in turn, to be a risk factor for hypertension. PMID:25774936

  5. Diversity of the vaginal microbiome correlates with preterm birth.

    PubMed

    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

    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

  6. Diversity of the Vaginal Microbiome Correlates With Preterm Birth

    PubMed Central

    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

    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

  7. Bootstrap standard error and confidence intervals for the correlation corrected for range restriction: a simulation study.

    PubMed

    Chan, Wai; Chan, Daniel W-L

    2004-09-01

    The standard Pearson correlation coefficient is a biased estimator of the true population correlation, rho, when the predictor and the criterion are range restricted. To correct the bias, the correlation corrected for range restriction, rc, has been recommended, and a standard formula based on asymptotic results for estimating its standard error is also available. In the present study, the bootstrap standard-error estimate is proposed as an alternative. Monte Carlo simulation studies involving both normal and nonnormal data were conducted to examine the empirical performance of the proposed procedure under different levels of rho, selection ratio, sample size, and truncation types. Results indicated that, with normal data, the bootstrap standard-error estimate is more accurate than the traditional estimate, particularly with small sample size. With nonnormal data, performance of both estimates depends critically on the distribution type. Furthermore, the bootstrap bias-corrected and accelerated interval consistently provided the most accurate coverage probability for rho. PMID:15355154

  8. Evaluation of Correlation of Blood Glucose and Salivary Glucose Level in Known Diabetic Patients

    PubMed Central

    Singh, Siddharth Kumar; Padmavathi, B.N.; Rajan, S.Y.; Mamatha, G.P.; Kumar, Sandeep; Roy, Sayak; Sareen, Mohit

    2015-01-01

    Introduction Diabetes mellitus is a chronic heterogenous disease in which there is dysregulation of carbohydrates, protein and lipid metabolism; leading to elevated blood glucose levels. The present study was conducted to evaluate the correlation between blood glucose and salivary glucose levels in known diabetic patients and control group and also to evaluate salivary glucose level as a diagnostic tool in diabetic patients. Materials and Methods A total number of 250 patients were studied, out of which 212 formed the study group and 38 formed the control group. Result Among 250 patients, correlation was evaluated between blood glucose and salivary glucose values which on analysis revealed Pearson correlation of 0.073. The p-value was 0.247, which was statistically non significant. Conclusion Salivary glucose values cannot be considered as a diagnostic tool for diabetic individuals.

  9. Is There Any Correlation Between Patient Height and Patellar Tendon Length?

    PubMed Central

    Navali, Amir M; Jafarabadi, Mohammad Asghari

    2015-01-01

    Background: A potential specific problem of patellar tendon graft in ACL reconstruction is the possibility of graft-tunnel mismatch which could be more problematic with anatomic ACL reconstruction where the femoral tunnel is placed low on the lateral wall of the lateral femoral condyle. The occasional occurrence of this mismatch raises the question that whether a correlation exists between patient height and patellar tendon length. The purpose of the present study was to measure patellar tendon length as an anthropometric finding and to evaluate whether a correlation exists between patient height and patellar tendon length. Methods: Intra-operative measurement of patellar tendon length was carried out in 267 consecutive patients during bone-patellar tendon-bone (BTB) graft ACL reconstruction. Patient age, gender, height were recorded. The patellar tendon measurements were done independently by two surgeons and the possible inter-observer errors were checked. The data were analyzed using the Pearson correlation. Results: The mean length of the patellar tendon was 46.4 ± 4.8 mm (Mean ± SD) with a range of 32–61 mm. The mean patient height was 177 ± 7 cm (Mean ± SD) with a range of 159–197 cm. A weak positive correlations were found between patient height and patellar tendon length (Pearson r = 0.24, P< 0.001). The linear regression equation for patellar tendon length (y, in millimeters) as a function of patient height (x, in centimeters) can be expressed as y=16.54 + 0.17x. Conclusions: Our study showed a weak correlation between patellar tendon length and patient height. This finding is in contrast to the usual measurements in human anthropometry in which taller individuals have normally longer tendons and ligaments. The graft-tunnel mismatch may be the result of this variation.

  10. Correlative study of 3 pain rating scales among obstetric patients.

    PubMed

    Akinpelu, A O; Olowe, O O

    2002-06-01

    The relationship between pain scores obtained on the Visual Analog Scale (VAS) the Box Numerical Scale (BNS) and Verbal Rating Scale (VRS) was studied. The subjects were 35 volunteer female patients who had their babies through caesarian section 1-3 days prior to the study. Demographic data and pain scores were collected through a questionnaire, which was available in both English and Yoruba, the two most commonly spoken languages in Ibadan where the study was carried out. Data were analysed using Pearson Product, Moment Correlation Coefficient, and One-way Analysis of Variance. Results indicated that there was no significant difference between the pain scores obtained on the 3 pain rating scales. Significant correlations existed between pain scores obtained on the VAS and VRS (r = 0.48, p = 0.003); VAS and BNS (r = 0.74, P = 0.000); BNS and VRS (r = 0.74, P = 0.000). High educational attainment improved correlation between the scales in this study. It was concluded that the three pain rating scales measure the same construct, and could be used for pain measurement in obstetrically related conditions in this environment. PMID:12518906

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

    PubMed Central

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

    2012-01-01

    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

  12. Psychological profile in burning mouth syndrome

    Microsoft Academic Search

    Firas A. M. Al Quran

    2004-01-01

    Thirty-two patients with burning mouth syndrome and 32 matched control subjects were evaluated for their personality profile using a comprehensive, reliable, and validated inventory. All subjects were requested to complete the Neo PI-R questionnaire that measures the 5 dimensions of personality and their facets. A t-test and univariate correlations (Pearson's correlation coefficient) were used to compare the 2 groups. Results

  13. Correlation of serum uric acid with bone mineral density and fragility fracture in patients with primary osteoporosis: a single-center retrospective study of 253 cases

    PubMed Central

    Chen, Lin; Peng, Yongde; Fang, Fang; Chen, Jinyu; Pan, Ling; You, Li

    2015-01-01

    Objective: This study aimed to investigate the correlation of serum uric acid with bone mineral density (BMD) and fragility fracture in primary osteoporosis (PO) patients. Methods: A retrospective analysis of biochemical parameters including bone turnover markers and bone density was done in patients (n=253) received initial treatment for PO from January 2011 to May 2012 at the Shanghai First People’s Hospital. Results: Pearson correlation analysis and multiple regression analysis showed that serum uric acid positively correlated with the lumbar spine BMD (P<0.05); serum uric acid negatively correlated with urine calcium/creatinine ratio, but positively correlated with blood 25-hydroxyvitamin D (25 [OH] D) (P<0.05); the serum uric acid in postmenopausal women with the history of fragility fracture was significantly lower than that in women without the this disease history. Conclusion: Serum uric acid may be a protective factor of bone metabolism in primary osteoporosis patients.

  14. Information-limiting correlations.

    PubMed

    Moreno-Bote, Rubén; Beck, Jeffrey; Kanitscheider, Ingmar; Pitkow, Xaq; Latham, Peter; Pouget, Alexandre

    2014-10-01

    Computational strategies used by the brain strongly depend on the amount of information that can be stored in population activity, which in turn strongly depends on the pattern of noise correlations. In vivo, noise correlations tend to be positive and proportional to the similarity in tuning properties. Such correlations are thought to limit information, which has led to the suggestion that decorrelation increases information. In contrast, we found, analytically and numerically, that decorrelation does not imply an increase in information. Instead, the only information-limiting correlations are what we refer to as differential correlations: correlations proportional to the product of the derivatives of the tuning curves. Unfortunately, differential correlations are likely to be very small and buried under correlations that do not limit information, making them particularly difficult to detect. We found, however, that the effect of differential correlations on information can be detected with relatively simple decoders. PMID:25195105

  15. Information-limiting correlations

    PubMed Central

    Moreno-Bote, Rubén; Beck, Jeffrey; Kanitscheider, Ingmar; Pitkow, Xaq; Latham, Peter; Pouget, Alexandre

    2015-01-01

    Computational strategies used by the brain strongly depend on the amount of information that can be stored in population activity, which in turn strongly depends on the pattern of noise correlations. In vivo, noise correlations tend to be positive and proportional to the similarity in tuning properties. Such correlations are thought to limit information, which has led to the suggestion that decorrelation increases information. In contrast, we found, analytically and numerically, that decorrelation does not imply an increase in information. Instead, the only information-limiting correlations are what we refer to as differential correlations: correlations proportional to the product of the derivatives of the tuning curves. Unfortunately, differential correlations are likely to be very small and buried under correlations that do not limit information, making them particularly difficult to detect. We found, however, that the effect of differential correlations on information can be detected with relatively simple decoders. PMID:25195105

  16. Correlation between serum gastrin and cellular proliferation in Barrett’s esophagus

    PubMed Central

    Green, Daniel A.; Mlynarczyk, Carrie M.; Vaccaro, Benjamin J.; Capiak, Kristina M.; Quante, Michael; Lightdale, Charles J.; Abrams, Julian A.

    2011-01-01

    Background: Patients with Barrett’s esophagus (BE) are commonly treated with proton-pump inhibitors (PPIs) to minimize the exposure of esophageal mucosa to stomach acid. However, the use of these medications can lead to significant hypergastrinemia in a subset of patients, which is concerning due to the known tumorigenic and proliferative effects of gastrin. The present pilot study aims to investigate a potential correlation between serum gastrin and cellular proliferation in BE. Methods: We performed a cross-sectional analysis of patients with nondysplastic BE on PPI therapy. Fasting serum gastrin was measured on the same day as esophageal biopsies were obtained. These biopsies were then stained with Ki-67 nuclear antibody. Pearson’s correlation coefficient was calculated to assess the relationship between Ki-67 index and ln(gastrin). Results: A total of 10 patients were included in the study. The mean age was 62.6 (±8.4) years and 5 patients were male. The median serum gastrin level was 45.2 pM (interquartile range [IQR] 33–113) and the median Ki-67 index was 49.6% (IQR 23–64). We found a statistically significant positive correlation between Ki-67 index and ln(gastrin) (r?=?0.64; p?=?0.05). Conclusions: In nondysplastic BE patients on PPI therapy, serum gastrin levels were significantly correlated with cellular proliferation. These pilot data lend support to a potential causal effect of gastrin on neoplastic progression in BE. Longitudinal studies of patients with BE are needed to determine whether hypergastrinemia is a risk factor for the development of dysplasia and adenocarcinoma or could be used as a biomarker for disease progression. PMID:21694810

  17. Correlations of coronary plaque wall thickness with wall pressure and wall pressure gradient: a representative case study

    PubMed Central

    2012-01-01

    Background There are two major hemodynamic stresses imposed at the blood arterial wall interface by flowing blood: the wall shear stress (WSS) acting tangentially to the wall, and the wall pressure (WP) acting normally to the wall. The role of flow wall shear stress in atherosclerosis progression has been under intensive investigation, while the impact of blood pressure on plaque progression has been under-studied. Method The correlations of wall thickness (WT) with wall pressure (WP, blood pressure on the lumen wall) and spatial wall pressure gradient (WPG) in a human atherosclerotic right coronary artery were studied. The pulsatile blood flow was simulated using a three dimensional mathematical model. The blood was treated as an incompressible viscous non-Newtonian fluid. The geometry of the artery was re-constructed using an in vivo intravascular ultrasound (IVUS) 44-slice dataset obtained from a patient with consent obtained. The WT, the WP and the WPG were averaged on each slice, respectively, and Pearson correlation analysis was performed on slice averaged base. Each slice was then divided into 8 segments and averaged vessel WT, WP and WPG were collected from all 352 segments for correlation analysis. Each slice was also divided into 2 segments (inner semi-wall of bend and outer semi-wall of bend) and the correlation analysis was performed on the 88 segments. Results Under mean pressure, the Pearson coefficient for correlation between WT and WP was r?=?? 0.52 (p?Pearson coefficient for correlation between WT and WPG was r?=?0.30 (p?=?0.004) by 2-segment analysis and r?=?0.45 (p?=?0.002) by slice averaged analysis, respectively. The r-values corresponding to systole and diastole pressure conditions were similar. Conclusions Results from this representative case report indicated that plaque wall thickness correlated negatively with wall pressure (r?=??0.81 by slice) and positively with wall pressure gradient (r?=?0.45). The slice averaged WT has a strong linear relationship with the slice averaged WP. Large-scale patient studies are needed to further confirm our findings. PMID:22839647

  18. SPATIAL CORRELATION FOR CORRELATED SCATTERERS Terence Betlehem

    E-print Network

    Abhayapala, Thushara D.

    created by correlated scat- terers. We derive a closed form expression for the correla- tion in fields of rays reflecting off homogeneous diffuse scat- terers. At the receiver, rays have similar amplitudes

  19. Does leadership effectiveness correlates with leadership styles in healthcare executives of Iran University of Medical Sciences

    PubMed Central

    Ebadifard Azar, Farbod; Sarabi Asiabar, Ali

    2015-01-01

    Background: Effective leadership is essential to passing through obstacles facing the health field.The current health care system in Iran has major problems and gaps in the field of effective leadership. The aim of this study was to evaluate hospital managers’ leadership style through selfassessment and to determine the correlation between leadership styles with healthcare executives’ leadership readiness and leadership effectiveness. Methods: In this cross-sectional study a self-administered questionnaire completed by all internal healthcare executives of all teaching and non-teaching hospitals affiliated to Iran University of Medical Sciences. Questionnaire was composed to determine demographic information, leadership style questions, leadership effectiveness and leadership readiness. Descriptive statistics and Pearson correlation coefficient were used for data analysis. Results: According to the findings, the dominant style of healthcare executives was transformational leadership style (with a score of 4.34). The leadership effectiveness was estimated at about 4.36 that shows the appropriate level of leadership effectiveness. There was a significant correlation (correlation coefficient of 0.244) between leadership readiness and transformational leadership style (p<0.05). Also, there was a significant correlation between leadership effectiveness with transformational (0.051) and transactional (0.216) styles. Conclusion: There was a correlation between leadership readiness and leadership effectiveness with leadership styles. Application of this research will be crucial to universities and healthcare executives. This study suggests that strengthening the scientific basis is essential for leadership readiness and leadership effectiveness in healthcare system. PMID:26000260

  20. Bounded-observation Kalman filtering of correlation in multivariate neural recordings.

    PubMed

    Mehdi Kafashan, Mohammad; Palanca, Ben J; ShiNung Ching

    2014-08-01

    A persistent question in multivariate neural signal processing is how best to characterize the statistical association between brain regions known as functional connectivity. Of the many metrics available for determining such association, the standard Pearson correlation coefficient (i.e., the zero-lag cross-correlation) remains widely used, particularly in neuroimaging. Generally, the cross-correlation is computed over an entire trial or recording session, with the assumption of within-trial stationarity. Increasingly, however, the length and complexity of neural data requires characterizing transient effects and/or non-stationarity in the temporal evolution of the correlation. That is, to estimate dynamics in the association between brain regions. Here, we present a simple, data-driven Kalman filter-based approach to tracking correlation dynamics. The filter explicitly accounts for the bounded nature of correlation measurements through the inclusion of a Fisher transform in the measurement equation. An output linearization facilitates a straightforward implementation of the standard recursive filter equations, including admittance of covariance identification via an autoregressive least squares method. We demonstrate the efficacy and utility of the approach in an example of multivariate neural functional magnetic resonance imaging data. PMID:25571128

  1. Reverse Correlation in Neurophysiology

    ERIC Educational Resources Information Center

    Ringach, Dario; Shapley, Robert

    2004-01-01

    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…

  2. Ska Correlator Advances

    Microsoft Academic Search

    John D. Bunton; CSIRO ICT

    2004-01-01

    When the SKA was proposed, a major technical obstacle to its feasibility was the cost of the correlator. Significant advances made in correlator design since then are described. These advances have made SKA correlator possible within reasonable cost constrains. At the same time performance issues with the proposed FX architecture have been addressed.

  3. What Is Strong Correlation?

    ERIC Educational Resources Information Center

    Kozak, Marcin

    2009-01-01

    Interpretation of correlation is often based on rules of thumb in which some boundary values are given to help decide whether correlation is non-important, weak, strong or very strong. This article shows that such rules of thumb may do more harm than good, and instead of supporting interpretation of correlation--which is their aim--they teach a…

  4. VLBI Correlators in Kashima

    NASA Technical Reports Server (NTRS)

    Sekido, Mamoru; Takefuji, Kazuhiro

    2013-01-01

    Kashima Space Technology Center (KSTC) is making use of two kinds of software correlators, the multi-channel K5/VSSP software correlator and the fast wide-band correlator 'GICO3,' for geodetic and R&D VLBI experiments. Overview of the activity and future plans are described in this paper.

  5. Parent-Child Resemblance in Weight Status and Its Correlates in the United States

    PubMed Central

    Liang, Lan; Wang, Youfa

    2013-01-01

    Background Few studies have examined parent-child resemblance in body weight status using nationally representative data for the US. Design We analyzed Body Mass Index (BMI), weight status, and related correlates for 4,846 boys, 4,725 girls, and their parents based on US nationally representative data from the 2006 and 2007 Medical Expenditure Panel Survey (MEPS). Pearson partial correlation coefficients, percent agreement, weighted kappa coefficients, and binary and multinomial logistic regression were used to examine parent-child resemblance, adjusted for complex sampling design. Results Pearson partial correlation coefficients between parent and child’s BMI measures were 0.15 for father-son pairs, 0.17 for father-daughter pairs, 0.20 for mother-son pairs, and 0.23 for mother-daughter pairs. The weighted kappa coefficients between BMI quintiles of parent and child ranged from ?0.02 to 0.25. Odds ratio analyses found children were 2.1 (95% confidence interval (CI): 1.6, 2.8) times more likely to be obese if only their father was obese, 1.9 (95% CI: 1.5, 2.4) times more likely if only their mother was obese, and 3.2 (95% CI: 2.5, 4.2) times more likely if both parents were obese. Conclusions Parent-child resemblance in BMI appears weak and may vary across parent-child dyad types in the US population. However, parental obesity status is associated with children’s obesity status. Use of different measures of parent-child resemblance in body weight status can lead to different conclusions. PMID:23762352

  6. The Precise Determination of Vascular Lumen and Stent Diameters: Correlation Among Calibrated Angiography, Intravascular Ultrasound, and Pressure-Fixed Specimens

    SciTech Connect

    Froelich, Jens J.; Hoppe, Martin; Nahrstedt, Christoph [Medizinisches Zentrum fuer Radiologie, Abteilung fuer Strahlendiagnostik, Klinikum der Philipps-Universitaet, Baldingerstrasse, D-35043 Marburg (Germany); Barth, Klemens H. [Division of Vascular and Interventional Radiology, Georgetown University Hospital, 3800 Reservoir Road, N.W., Washington, DC 20007 (United States); Wagner, H. Joachim; Klose, Klaus J. [Medizinisches Zentrum fuer Radiologie, Abteilung fuer Strahlendiagnostik, Klinikum der Philipps-Universitaet, Baldingerstrasse, D-35043 Marburg (Germany)

    1997-11-15

    Purpose: Luminal diameters measured in vivo by calibrated-catheter angiography and by intravascular ultrasound were correlated with those obtained from pressure-fixed histologic cross-sections to determine the accuracy of both methods. Methods: Angiographic and endosonographic diameter measurements were performed in the center of stents placed in the iliac arteries of 10 miniature pigs and were compared with luminal and stent diameters in postmortem, pressure-fixed, histologic cross-sections from identical locations. Results: Compared with histologic diameters, magnification-corrected angiographic measurements still magnified vascular luminal diameters by 0.7 {+-} 0.71 mm (r= 0.41, Pearson; p < 0.003, Wilcoxon, matched pairs), whereas intravascular ultrasound measurements proved to be almost identical to the histologic lumina (r= 0.95, Pearson; p> 0.5, Wilcoxon, matched pairs). Similarly, stent diameters correlated well between endosonographic and histologic measurements (r= 0.91; p= 0.002), and less well between angiographic and histologic diameters (r= 0.62; p= 0.002). Conclusion: Since calibrated angiography still overestimates vascular lumina, endosonography is the preferred technique for accurate in vivo measurements.

  7. Correlation between single limb support phase and self-evaluation questionnaires in knee osteoarthritis populations

    PubMed Central

    DEBI, RONEN; MOR, AMIT; SEGAL, GANIT; SEGAL, OFER; AGAR, GABRIEL; DEBBI, EYTAN; HALPERIN, NAHUM; HAIM, AMIR; ELBAZ, AVI

    2011-01-01

    Purpose. To investigate the correlation between single limb support (SLS) phase (% of gait cycle) and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) questionnaire and Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36 Health Survey) in patients with knee osteoarthritis (OA). Method. A prospective observational study was employed with 125 adults with bilateral medial compartment symptomatic knee OA who underwent a physical and radiographic evaluation. Velocity, step length and SLS were assessed by a computerised mat (GAITRite). Patients completed the WOMAC and SF-36 Health Survey questionnaires. Results. Statistical analysis examined the correlations between SLS and both questionnaires, between Kellgren & Lawrence (K&L) scores and both questionnaires and between SLS correlations and K&L correlations. We found significantly stronger correlations between SLS and WOMAC-pain, WOMAC-function, the SF-36 pain sub-category, velocity and step length than between K&L scores and these parameters (Pearson's r— 0.50 vs. 0.26, 0.53 vs. 0.34, 0.50 vs. 023, 0.81 vs. 0.33, 0.77 vs. 0.37, respectively; all p 5 0.05). Significant differences in SLS were found over WOMAC-pain, WOMAC-function and SF-36 overall score quartiles (p 5 0.05 for all). Conclusion. We recommend integrating SLS as an objective parameter in the comprehensive evaluation of patients with knee OA. PMID:21208029

  8. High Frequency Correlation Modelling

    Microsoft Academic Search

    Nicolas Huth; Frédéric Abergel

    2011-01-01

    \\u000a Many statistical arbitrage strategies, such as pair trading or basket trading, are based on several assets. Optimal execution\\u000a routines should also take into account correlation between stocks when proceeding clients orders. However, not so much effort\\u000a has been devoted to correlation modelling and only few empirical results are known about high frequency correlation. Depending\\u000a on the time scale under consideration,

  9. Correlation interferometer geolocation

    Microsoft Academic Search

    Keith Struckman; Nashua NH

    2006-01-01

    Geolocation solutions based on the correlation interferometer geolocation (CIGL) equation depend on searching over (xi,y i) space and identifying the transmitter location as the (x,y) value that maximizes the correlation value. Under cross-polarized incident field conditions this correlation depends on both the array manifold calibration polarization and the targets transmission polarization. Computation of the transmitted polarization is accomplished by maximizing

  10. The t-test Tutorial: Comparing Cultures

    NSDL National Science Digital Library

    Berger, Dale

    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.

  11. FEBRUARY 2001 S&T TEST REPORT

    E-print Network

    Schrijver, Karel

    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

  12. RHIC DATA CORRELATION METHODOLOGY.

    SciTech Connect

    MICHNOFF,R.; D'OTTAVIO,T.; HOFF,L.; MACKAY,W.; SATOGATA,T.

    1999-03-29

    A requirement for RHIC data plotting software and physics analysis is the correlation of data from all accelerator data gathering systems. Data correlation provides the capability for a user to request a plot of multiple data channels vs. time, and to make meaningful time-correlated data comparisons. The task of data correlation for RHIC requires careful consideration because data acquisition triggers are generated from various asynchronous sources including events from the RHIC Event Link, events from the two Beam Sync Links, and other unrelated clocks. In order to correlate data from asynchronous acquisition systems a common time reference is required. The RHIC data correlation methodology will allow all RHIC data to be converted to a common wall clock time, while still preserving native acquisition trigger information. A data correlation task force team, composed of the authors of this paper, has been formed to develop data correlation design details and provide guidelines for software developers. The overall data correlation methodology will be presented in this paper.

  13. Diagnostic role of magnetic resonance cholangiopancreatography in evaluation of obstructive biliopathies and correlating it with final diagnosis and clinical profile of patients

    PubMed Central

    Parashari, Umesh Chandra; Khanduri, Sachin; Bhadury, Samarjit; Upadhyay, Deepika; Kishore, Kaushal

    2015-01-01

    Aims and Objective: We assessed the utility of magnetic resonance cholangiopancreatography (MRCP) as a noninvasive diagnostic tool in patients with obstructive biliopathies. Materials and Methods: A prospective study was conducted on 54 patients with clinically suspected biliary obstruction. MRCP in these patients was compared and correlated with final diagnosis and their clinical profile. Statistical Analysis: Sample profile was described in terms of sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy. Pearson's Chi-square statistics was used to assess the strength of association between diagnostic accuracy of MRCP and final diagnosis. Results: Out of the 54 patients, 50 had biliary obstruction. The cause of biliary obstruction was finally identified on the basis of direct cholangiography/surgery/histopathology. In 52 of the 54 patients, MRCP agreed with final diagnosis in identifying the level of block. MRCP agreed with final diagnosis in identifying the cause of obstruction in 48 of the 54 patients (89%). Sensitivity of MRCP in identifying the level of obstruction in comparison with final diagnosis was 100%, while diagnostic accuracy of MRCP in identifying the level of obstruction in comparison with final diagnosis was 96.29%. The correlation between MRCP and final diagnosis in diagnosing cause of obstruction was 0.95 (Pearson's correlation coefficient, P = 0.017). Conclusion: MRCP is a safe ionizing radiation and iodinated contrast free modality which has the ability to display the biliary tree by combining the advantages of projectional and cross-sectional imaging. PMID:25810650

  14. Explorations in Statistics: Correlation

    ERIC Educational Resources Information Center

    Curran-Everett, Douglas

    2010-01-01

    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…

  15. Isaac Gary Correlator and

    E-print Network

    #12;Isaac Gary #12;Correlator and DSP 12-bit Digitizer Analog fiber- optic cable On-bit Digitizer Analog fiber- optic cable On-line Calibration Data Storage LAN Internet Burst monitor;#12;#12;#12;Correlator and DSP 12-bit Digitizer Analog fiber- optic cable On-line Calibration Data Storage LAN Internet

  16. Explorations in statistics: correlation

    NSDL National Science Digital Library

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

    2010-10-01

    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.

  17. Ischemic Core and Penumbra in Human Stroke

    Microsoft Academic Search

    Anthony M. Kaufmann; Andrew D. Firlik; Melanie B. Fukui; Lawrence R. Wechsler; Charles A. Jungries; Howard Yonas

    2010-01-01

    were similarly assessed to determine the area of final infarct. Comparisons were analyzed with a paired Student's t test and Pearson's correlation coefficient. Results—Discrete and confluent areas of CBF #20 cm3 z 100 g21 z min21 were identified in all patients, ipsilateral to the symptomatic MCA territory. The average area of CBF #20 cm3 z 100 g21 z min21 within

  18. Correlation of Standardized Uptake Value and Apparent Diffusion Coefficient in Integrated Whole-Body PET/MRI of Primary and Recurrent Cervical Cancer

    PubMed Central

    Grueneisen, Johannes; Beiderwellen, Karsten; Heusch, Philipp; Buderath, Paul; Aktas, Bahriye; Gratz, Marcel; Forsting, Michael; Lauenstein, Thomas; Ruhlmann, Verena; Umutlu, Lale

    2014-01-01

    Background To evaluate a potential correlation of the maximum standard uptake value (SUVmax) and the minimum apparent diffusion coefficient (ADCmin) in primary and recurrent cervical cancer based on integrated PET/MRI examinations. Methods 19 consecutive patients (mean age 51.6 years; range 30–72 years) with histopathologically confirmed primary cervical cancer (n?=?9) or suspected tumor recurrence (n?=?10) were prospectively enrolled for an integrated PET/MRI examination. Two radiologists performed a consensus reading in random order, using a dedicated post-processing software. Polygonal regions of interest (ROI) covering the entire tumor lesions were drawn into PET/MR images to assess SUVmax and into ADC parameter maps to determine ADCmin values. Pearson’s correlation coefficients were calculated to assess a potential correlation between the mean values of ADCmin and SUVmax. Results In 15 out of 19 patients cervical cancer lesions (n?=?12) or lymph node metastases (n?=?42) were detected. Mean SUVmax (12.5±6.5) and ADCmin (644.5±179.7×10?5 mm2/s) values for all assessed tumor lesions showed a significant but weak inverse correlation (R?=??0.342, p<0.05). When subdivided in primary and recurrent tumors, primary tumors and associated primary lymph node metastases revealed a significant and strong inverse correlation between SUVmax and ADCmin (R?=??0.692, p<0.001), whereas recurrent cancer lesions did not show a significant correlation. Conclusions These initial results of this emerging hybrid imaging technique demonstrate the high diagnostic potential of simultaneous PET/MR imaging for the assessment of functional biomarkers, revealing a significant and strong correlation of tumor metabolism and higher cellularity in cervical cancer lesions. PMID:24804676

  19. Gates, Pearson Partner on Common Core

    ERIC Educational Resources Information Center

    Gewertz, Catherine

    2011-01-01

    As states and school districts grapple with how to teach the skills outlined in the new common standards, two foundations have announced a partnership aimed at crafting complete, online curricula for those standards in mathematics and English/language arts that span nearly every year of a child's precollegiate education. The announcement last…

  20. A Maximum Entropy Test for Evaluating Higher-Order Correlations in Spike Counts

    PubMed Central

    Onken, Arno; Dragoi, Valentin; Obermayer, Klaus

    2012-01-01

    Evaluating the importance of higher-order correlations of neural spike counts has been notoriously hard. A large number of samples are typically required in order to estimate higher-order correlations and resulting information theoretic quantities. In typical electrophysiology data sets with many experimental conditions, however, the number of samples in each condition is rather small. Here we describe a method that allows to quantify evidence for higher-order correlations in exactly these cases. We construct a family of reference distributions: maximum entropy distributions, which are constrained only by marginals and by linear correlations as quantified by the Pearson correlation coefficient. We devise a Monte Carlo goodness-of-fit test, which tests - for a given divergence measure of interest - whether the experimental data lead to the rejection of the null hypothesis that it was generated by one of the reference distributions. Applying our test to artificial data shows that the effects of higher-order correlations on these divergence measures can be detected even when the number of samples is small. Subsequently, we apply our method to spike count data which were recorded with multielectrode arrays from the primary visual cortex of anesthetized cat during an adaptation experiment. Using mutual information as a divergence measure we find that there are spike count bin sizes at which the maximum entropy hypothesis can be rejected for a substantial number of neuronal pairs. These results demonstrate that higher-order correlations can matter when estimating information theoretic quantities in V1. They also show that our test is able to detect their presence in typical in-vivo data sets, where the number of samples is too small to estimate higher-order correlations directly. PMID:22685392

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

    PubMed

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

    2015-01-01

    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

  2. Correlation reflectometry at TEXTOR

    NASA Astrophysics Data System (ADS)

    Krämer-Flecken, A.; Soldatov, S.; Vowinkel, B.; Müller, P.

    2010-11-01

    In high temperature fusion plasmas the transport of energy and particles is commonly believed to be driven by turbulence. Turbulence quantities as correlation length and decorrelation time are important for the confinement properties of a plasma. Besides other diagnostics, correlation reflectometry has proven to be a suitable tool for the measurement of turbulence properties. At the medium sized Toroidal EXperiment for Technical Oriented Research (TEXTOR) the existing correlation reflectometry has been recently upgraded. A new reflectometer based on a microwave synthesizer has been developed and installed for the investigation of turbulence properties in a fusion plasma. Together with the existing reflectometer the measurement of radial correlation length and decorrelation time becomes available. Both reflectometers are computer controlled and allow to program individual frequency sequences and the duration of each frequency step. With the existing poloidal antenna array at ? =0° and on top of the vacuum vessel, the system allows the measurement of radial correlation and poloidal correlations at the same time. First experiments have been performed and the results on the radial correlation length of density fluctuations in a fusion plasma are presented.

  3. Haystack Observatory VLBI Correlator

    NASA Technical Reports Server (NTRS)

    Titus, Mike; Cappallo, Roger; Corey, Brian; Dudevoir, Kevin; Niell, Arthur; Whitney, Alan

    2013-01-01

    This report summarizes the activities of the Haystack Correlator during 2012. Highlights include finding a solution to the DiFX InfiniBand timeout problem and other DiFX software development, conducting a DBE comparison test following the First International VLBI Technology Workshop, conducting a Mark IV and DiFX correlator comparison, more broadband delay experiments, more u- VLBI Galactic Center observations, and conversion of RDV session processing to the Mark IV/HOPS path. Non-real-time e-VLBI transfers and engineering support of other correlators continued.

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

    PubMed Central

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

    2014-01-01

    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

  5. Quantitative correlation of breast tissue parameters using magnetic resonance and X-ray mammography.

    PubMed Central

    Graham, S. J.; Bronskill, M. J.; Byng, J. W.; Yaffe, M. J.; Boyd, N. F.

    1996-01-01

    Previous investigators have shown that there is a strong association between the fraction of fibroglandular tissue within the breast as determined by X-ray mammography (per cent density) and breast cancer risk. In this study, the quantitative correlation between per cent density and two objective magnetic resonance (MR) parameters of breast tissue, relative water content and mean T2 relaxation time, as investigated for 42 asymptomatic subjects. Using newly developed, rapid techniques MR measurements were performed on a volume-of-interest incorporating equal, representative portions of both breasts. X-ray mammograms of each subject were digitised and analysed semiautomatically to determine per cent density. Relative water content showed a strong positive correlation with per cent density (Pearson correlation coefficient rp = 0.79, P < 0.0001) and mean T2 value showed a strong negative correlation with per cent density (rp = -0.61, P < 0.0001). The MR and X-ray parameters were also associated with sociodemographic and anthropometric risk factors for breast cancer (P < 0.05). The potential use of MR parameters to assess risk of breast cancer and to provide a frequent, non-hazardous monitor of breast parenchyma is discussed. Images Figure 2 PMID:8546901

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

    PubMed Central

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

    2014-01-01

    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

  7. Prevalence and correlates of depressive symptoms and resiliency among African American women in a community-based primary health care center.

    PubMed

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

    2013-11-01

    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

  8. Fluorescence Correlation Spectroscopy

    NSDL National Science Digital Library

    Haustein, Elke

    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.

  9. The correlation bell inequalities

    NASA Astrophysics Data System (ADS)

    Andreev, V. A.

    2009-02-01

    We consider the Bell and Bell-Clauser-Horne-Shimony-Holt inequalities for two-particle spin states. It is known that these inequalities are violated in experimental verification. We show that this can be explained because these inequalities are proved for correlation functions of random variables that are totally unrelated to one another, while the verification is done using correlation functions in which random variables refer to a pair of particles forming a two-particle state. In the case of entangled states, these random functions are dependent, and their correlation coefficient is nonzero. We give inequalities that explicitly involve this correlation coefficient. For factorable and separable states, these inequalities coincide with the standard Bell and Bell-Clauser-Horne-Shimony-Holt inequalities.

  10. Correlation Guessing Game

    NSDL National Science Digital Library

    Roger Woodard

    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.

  11. Compact Optical Correlators

    NASA Astrophysics Data System (ADS)

    Gregory, Don A.; Kirsch, James C.

    1989-02-01

    In the past 15 years, a dozen or so designs have been proposed for compact optical correlators. Of these, maybe one-third of them have actually been built and only a few of those tested. This paper will give an overview of some of the systems that have been built as well as mention some promising early and current designs that have not been built. The term compact, as used in the title of this paper, will be applied very loosely; to mean smaller than a laboratory size optical table. To date, only one correlator has been built and tested that actually can be called miniature. This softball size correlator was built by the Perkin-Elmer Corporation for the U. S. Army Missile Command at Redstone Arsenal, Alabama. More will be said about this correlator in following sections.

  12. Optimal separable correlation filters

    NASA Astrophysics Data System (ADS)

    McFadden, Frank E.

    2002-07-01

    Separable filters, because they are specified separately in each dimension, require less memory space and present opportunities for faster computation. Mahalanobis and Kumar1 presented a method for deriving separable correlation filters, but the filters were required to satisfy a restrictive assumption, and were thus not fully optimized. In this work, we present a general procedure for deriving separable versions of any correlation filter, using singular value decomposition (SVD), and prove that this is optimal for separable filters based on the Maximum Average Correlation Height (MACH) criterion. Further, we show that additional separable components may be used to improve the performance of the filter, with only a linear increase in computational and memory space requirements. MSTAR data is used to demonstrate the effects on sharpness of correlation peaks and locational precision, as the number of separable components is varied.

  13. Ozone Correlative Measurements Workshop

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E. (editor)

    1985-01-01

    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.

  14. Compact Optical Correlator

    NASA Technical Reports Server (NTRS)

    Scholl, Marija S.; Shumate, Michael S.; Hartman, Richard L.; Sloan, Jeffrey A.; Small, Donald W.

    1993-01-01

    Optical cross-correlator indicates position of target (if any) in scene matching target encoded in matched filter. Size reduced by use of prisms to fold optical path. Device designed, assembled from commercial components, and tested to verify feasibility of miniaturization for eventual incorporation into navigational and/or control systems of autonomous vehicles. For example, aircraft equipped with optical correlator recognizes prescribed target and measures its position, so that it lands on target under automatic control.

  15. Tsukuba VLBI Correlator

    NASA Technical Reports Server (NTRS)

    Kurihara, Shinobu; Nozawa, Kentaro

    2013-01-01

    The K5/VSSP software correlator (Figure 1), located in Tsukuba, Japan, is operated by the Geospatial Information Authority of Japan (GSI). It is fully dedicated to processing the geodetic VLBI sessions of the International VLBI Service for Geodesy and Astrometry. All of the weekend IVS Intensives (INT2) and the Japanese domestic VLBI observations organized by GSI were processed at the Tsukuba VLBI Correlator.

  16. Insulin-like growth factors in endometrioid adenocarcinoma: Correlation with clinico-pathological features and estrogen receptor expression

    PubMed Central

    2012-01-01

    Background Endometrial carcinoma is a common malignancy of female genital tract. Insulin-like growth factor is known to elicit estrogen-induced mitogenic activity and anti-apoptotic effect in endometrial tissues. Methods The retrospective study investigated the expression of insulin-like growth factors, estrogen receptors and their associations in endometrioid adenocarcinoma (EAC) from 80 EAC patients in immunohistochemistry, and 58 EAC patients and 42 control patients in quantitative RT-PCR. The Pearson correlation analysis was used to analyze their correlations with clinic-pathological parameters. Results Our results showed that insulin-like growth factor-1 and insulin-like growth factor-2 mRNA levels were higher in tumor tissues and tumor-adjacent tissues than those in control cells, and were inversely correlated with the malignancy of the tumor with a positive correlation with ER? and ER? expression. Insulin-like growth factor-1R protein expression was correlated with clinical stage, and insulin-like growth factor-2R protein expression was inversely correlated with histological grade. Conclusions Insulin-like growth factor system plays an important role in estrogen-induced endometrial carcinogenesis, and overexpression of insulin-like growth factor-1R in the advanced endometrioid adenocarcinoma is not estrogen-dependent. PMID:22720981

  17. Strongly correlated materials.

    PubMed

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

    2012-09-18

    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

  18. Correlates of cognitive change

    PubMed Central

    Salthouse, Timothy A.

    2014-01-01

    Although there has been considerable interest in identifying potential correlates of cognitive change, results of past studies have been inconsistent. The present study incorporated a number of methodological features intended to maximize sensitivity to detect characteristics of individuals with different amounts of cognitive change. Cognitive change in five cognitive abilities was analyzed with second-order latent growth curve models applied to data from a moderately large sample of healthy adults ranging from 18 to 99 years of age (N’s of 4,802 with one occasion, 2,265 with two occasions, and 1,128 with three occasions). There was significant individual difference variance in the longitudinal changes in several cognitive abilities, even in separate analyses of individuals between 18 and 39, 40 and 64, and over 65 years of age. Potential correlates of change included measures of self-rated health, vision, mood, personality, and lifestyle. Most of the potential correlates of change had high reliability, and several analyses were based on even more reliable factors determined by the variance common to multiple measures. Despite favorable conditions for detecting correlates of change, there was little evidence that cognitive change was moderated by any of the variables examined. Possible reasons for the inconsistent results regarding correlates of cognitive change are discussed. PMID:24219021

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

    PubMed Central

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

    2014-01-01

    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

  20. The observed radio/gamma-ray emission correlation for blazars with the Fermi-LAT and the RATAN-600 data

    NASA Astrophysics Data System (ADS)

    Mufakharov, T.; Mingaliev, M.; Sotnikova, Yu.; Naiden, Ya.; Erkenov, A.

    2015-07-01

    We study the correlation between gamma-ray and radio band radiation for 123 blazars, using the Fermi-LAT first source catalogue (1FGL) and the RATAN-600 data obtained at the same period of time (within a few months). We found an apparent positive correlation for BL Lac and flat-spectrum radio quasar (FSRQ) sources from our sample through testing the value of the Pearson product-moment correlation coefficient. The BL Lac objects show higher values of the correlation coefficient than FSRQs at all frequencies, except 21.7 GHz, and at all bands, except 10-100 GeV, typically at high confidence level (>99 per cent). At higher gamma-ray energies the correlation weakens and even becomes negative for BL Lacs and FSRQs. For BL Lac blazars, the correlation of the fluxes appeared to be more sensitive to the considered gamma-ray energy band, than to the frequency, while for FSRQ sources the correlation changed notably both with the considered radio frequency and gamma-ray energy band. We used a data randomization method to quantify the significance of the computed correlation coefficients. We find that the statistical significance of the correlations we obtained between the flux densities at all frequencies and the photon flux in all gamma-ray bands below 3 GeV is high for BL Lacs (chance probability ˜10-3-10-7). The correlation coefficient is high and significant for the 0.1-0.3 GeV band and low and insignificant for the 10-100 GeV band for both types of blazars for all considered frequencies.

  1. Advanced quantum noise correlations

    NASA Astrophysics Data System (ADS)

    Vogl, Ulrich; Glasser, Ryan T.; Clark, Jeremy B.; Glorieux, Quentin; Li, Tian; Corzo, Neil V.; Lett, Paul D.

    2014-01-01

    We use the quantum correlations of twin beams of light to investigate the fundamental addition of noise when one of the beams propagates through a fast-light medium based on phase-insensitive gain. The experiment is based on two successive four-wave mixing processes in rubidium vapor, which allow for the generation of bright two-mode-squeezed twin beams followed by a controlled advancement while maintaining the shared quantum correlations between the beams. The demonstrated effect allows the study of irreversible decoherence in a medium exhibiting anomalous dispersion, and for the first time shows the advancement of a bright nonclassical state of light. The advancement and corresponding degradation of the quantum correlations are found to be operating near the fundamental quantum limit imposed by using a phase-insensitive amplifier.

  2. Correlated Variability in Blazars

    E-print Network

    Robert Wagner

    2008-08-19

    Blazars are thought to emit highly-collimated outflows, so-called jets. By their close alignment to our line of sight, relativistic beaming effects enable us to observe these jets over the whole electromagnetic spectrum up to TeV energies, making them ideal laboratories for studying jet physics. In the last years multiwavelength observations of blazars provided us with detailed data sets which helped to characterize the two main components of the non-relativistic emission, peaking in the optical to X-ray and GeV/TeV energy region, respectively. In leptonic acceleration models, they are explained by synchrotron radiation of electrons and inverse-Compton emission from the same electron population and thus, correlations of both emission regimes are expected. We review recent observational results on the presence and absence of such correlations in blazars, and discuss constraints on emission models by quantitative correlation analyses.

  3. Nonlocality of quantum correlations

    E-print Network

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

    2012-01-01

    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.

  4. X-linked adrenoleukodystrophy: correlation between Loes score and diffusion tensor imaging parameters

    PubMed Central

    Ono, Sergio Eiji; de Carvalho Neto, Arnolfo; Gasparetto, Emerson Leandro; Coelho, Luiz Otávio de Mattos; Escuissato, Dante Luiz; Bonfim, Carmem Maria Sales; Ribeiro, Lisandro Lima

    2014-01-01

    Objective The present study was aimed at evaluating the correlation between diffusion tensor imaging parameters and Loes score as well as whether those parameters could indicate early structural alterations. Materials and Methods Diffusion tensor imaging measurements were obtained in 30 studies of 14 patients with X-linked adrenoleukodystrophy and were correlated with Loes scores. A control group including 28 male patients was created to establish agematched diffusion tensor imaging measurements. Inter- and intraobserver statistical analyses were undertaken. Results Diffusion tensor imaging measurements presented strong Pearson correlation coefficients (r) of –0.86, 0.89, 0.89 and 0.84 for fractional anisotropy and mean, radial and axial diffusivities (p < 0.01). Analysis of changes in diffusion tensor measurements at early stage of the disease indicates that mean and radial diffusivities might be useful to predict the disease progression. Conclusion Measurements of diffusion tensor parameters can be used as an adjunct to the Loes score, aiding in the monitoring of the disease and alerting for possible Loes score progression in the range of interest for therapeutic decisions. PMID:25741116

  5. Growth Patterns of Subway/Metro Systems Tracked by Degree Correlation

    E-print Network

    Whitney, Daniel E

    2012-01-01

    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...

  6. Correlation at sea

    NASA Astrophysics Data System (ADS)

    Hartman, Richard L.; Farr, Keith B.; McColgan, Michele W.; Smith, Ralph G.

    1997-03-01

    This paper discusses an optical correlator interfaces to a FLIR and laser rangefinder to aid aircraft landing aboard an aircraft carrier. The purpose was to recognize aircraft and provide precision track in spite of the engine plume which is visible in IR images. Toward the end of the program, an opportunity arose to piggyback on tests of a Navy FLIR system, on board the USS Enterprise. The Navy's developmental FLIR and laser rangefinder were mounted on the carrier and provided excellent imagery with concurrent range data. The correlator performed a limited set of experiments at sea, tracking an aircraft from 8000 feet until almost touchdown. The challenges to the correlator we operation in a harsh environment and real time interfacing with other hardware. Real time range information controlled a series of filters in the correlator. The system fit into a standard panel rack and utilized remote alignment. The system operated during the chock of aircraft launch and landing, with no need to open up the optical box.

  7. Stochastic correlative learning algorithms

    Microsoft Academic Search

    Simon Haykin; Zhe Chen; Suzanna Becker

    2004-01-01

    This paper addresses stochastic correlative learning as the basis for a broadly defined class of statistical learning algorithms known collectively as the algorithm of pattern extraction (ALOPEX) family. Starting with the neurobiologically motivated Hebb's rule, the two conventional forms of the ALOPEX algorithm are derived, followed by a modified variant designed to improve the convergence speed. We next describe two

  8. Informationally optimal correlation

    Microsoft Academic Search

    Olivier Gossner; Rida Laraki; Tristan Tomala

    2009-01-01

    This papers studies how to decompose a correlated distribution of actions, as a convex combination of indepedent distribution, in a way that is optimal for an information theory criterion. A characterization of optimal solutions is provided for 2?2 sets of actions. Then we give an application to the exact computation of maxmin values in some repeted games.

  9. DISCUSS: Regression and Correlation

    NSDL National Science Digital Library

    Hunt, Neville

    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.

  10. Correlation of Analytical Facilities

    Microsoft Academic Search

    Benjamin A. Moore

    1983-01-01

    New and emerging technologies such as VHSIC\\/VLSI and the expanded use of hybrids have presented a new series of problems in correlating analytical laboratory mass spectrometric moisture measurements. Standards and techniques, designed and tested for application in the more benign environment of smaller scale monolithic packaging, may not be directly applicable to new adsorption\\/desorption conditions and relatively large ( ¿lcc)

  11. Correlating Aluminum Burning Times

    Microsoft Academic Search

    M. W. Beckstead

    2005-01-01

    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,

  12. Jackknifing Disattenuated Correlations

    ERIC Educational Resources Information Center

    Rogers, W. Todd

    1976-01-01

    The utility of the jackknife for constructing confidence intervals and testing hypotheses about the disattenuated correlation is evaluated for small samples. Results of computer simulations support the claim that the jackknife can be used to construct confidence intervals but has limited utility for testing hypotheses about the disattenuated…

  13. Correlation and Regression

    NSDL National Science Digital Library

    Berger, Dale

    This applet allows the user to explore basic principles of correlation and regression. The user can manipulate points on a scatterplot. The user can then place a regression line on the plot and evaluate the resulting sums of squares error. An interesting feature of this applet is that it allows viewing of the sum of squares error as squares.

  14. Correlates of School Stress.

    ERIC Educational Resources Information Center

    Matthews, Doris B.

    As part of a continuing series of research studies on stress in schools, this study examined the construct validity of peripheral temperature at the fingertips as a measure of school stress. Measurements were made in classes selected at random from 11 volunteer schools in South Carolina. Three types of correlational studies were undertaken: (1)…

  15. Optic Nerve Head Morphology in Glaucoma Patients of African Descent is Strongly Correlated to Retinal Blood Flow

    PubMed Central

    Kanakamedala, Priyanka; Harris, Alon; Siesky, Brent; Tyring, Ariel; Muchnik, Michael; Eckert, George; Tobe, Leslie Abrams

    2014-01-01

    BACKGROUND/AIMS To examine the relationship between change in optic nerve head (ONH) morphology and retinal blood flow in patients with open-angle glaucoma (OAG) of African (AD) and European descent (ED) over three years. METHODS 112 patients with OAG (29 AD; 83 ED) underwent assessment of ONH morphology using Heidelberg retinal tomography (HRT-III) and retinal blood flow using confocal scanning laser Doppler. Repeated measures analysis of covariance was used to compare baseline and 3-year measurements and Pearson correlations were calculated to evaluate the relationships. RESULTS In OAG patients of AD, change in superior mean retinal blood flow was strongly, negatively correlated with change in cup/disc (C/D) area ratio (r=?0.78, p=0.020) and cup area (r=?0.75, p=0.0283) and strongly, positively correlated with change in rim area (r=0.74, p=0.0328) over three years. In OAG patients of AD, change in inferior mean retinal blood flow was strongly, negatively correlated with changes in C/D area ratio (r=?0.88, p=0.0156) and linear C/D ratio (r=?0.86, p=0.0265) over three years. In OAG patients of ED, these correlations were weak and did not reach statistical significance. DISCUSSION OAG patients of AD may have a stronger vascular component to their glaucoma pathophysiology than patients of ED. PMID:24964797

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

    DOE PAGESBeta

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

    2014-11-25

    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 catalog 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 catalog (together referred to as “VHE-like” sources) are distributed along underdense lines of sight at the 2.4#27; level. There is also a less suggestive correlation for the Fermi hard source population (1.7#27;). A correlation between 10-500 GeVmore »flux and underdense fraction along the line of sight for VHE-like and Fermi hard sources is found at 2.4#27; and 2.6#27;, 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 catalog, containing sources detected above 100 MeV, or the SDSS DR7 quasar catalog. 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% less than the nominal EBL density. Translating this into gamma-ray attenuation along the line of sight for a highly attenuated source with opacity #28;(E, z) #24; 5, we estimate that the attentuation of gamma-rays decreases no more than 10%. This decrease, although non-neglible, is unable to account for the apparent hard source correlation with underdense lines of sight.« less

  17. The Correlation of Retinal Nerve Fiber Layer Thickness With Blood Pressure in a Chinese Hypertensive Population.

    PubMed

    Gangwani, Rita A; Lee, Jacky W Y; Mo, H Y; Sum, Rita; Kwong, Alfred S K; Wang, Jenny H L; Tsui, Wendy W S; Chan, Jonathan C H; Lai, Jimmy S M

    2015-06-01

    To investigate the association between retinal nerve fiber layer (RNFL) thickness and blood pressure (BP) in subjects with systemic hypertension.Subjects with systemic hypertension on anti-hypertensive medications were screened by fundus photography and referred for glaucoma work-up if there was enlarged vertical cup-to-disc (VCDR) ratio ?0.6, VCDR asymmetry ?0.2, or optic disc hemorrhage. Workup included a complete ophthalmological examination, Humphrey visual field test, and RNFL thickness measurement by optical coherence tomography. The intraocular pressure (IOP) and RNFL thicknesses (global and quadrant) were averaged from both eyes and the means were correlated with: the systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP) using Pearson correlation.Among 4000 screened hypertensive subjects, 133 were referred for glaucoma workup and 110 completed the workup. Of the 4000 screened subjects, 1.3% had glaucoma (0.9% had normal tension glaucoma [NTG], 0.2% had primary open angle glaucoma, and 0.2% had primary angle closure glaucoma), whereas 0.3% were NTG suspects. The SBP was negatively correlated with the mean superior RNFL thickness (P?=?0.01). The DBP was negatively correlated with the mean global (P?=?0.03), superior (P?=?0.02), and nasal (P?=?0.003) RNFL thickness. The MAP was negatively correlated with the mean global (P?=?0.01), superior (P?=?0.002), and nasal (P?=?0.004) RNFL thickness while positively correlated with the mean IOP (P?=?0.02).In medically treated hypertensive subjects, glaucoma was present in 1.3%, with NTG being most prevalent. MAP control may help with IOP lowering and RNFL preservation, although future prospective studies will be needed. PMID:26061324

  18. Correlation of pre-veterinary admissions criteria, intra-professional curriculum measures, AVMA-COE professional competency scores, and the NAVLE.

    PubMed

    Roush, James K; Rush, Bonnie R; White, Brad J; Wilkerson, Melinda J

    2014-01-01

    Data consisting of preadmission criteria scores, annual and final cumulative grade point averages (GPAs), grades from individual professional courses, American Veterinary Medical Association Council on Education (AVMA-COE) Competency scores, annual class rank, and North American Veterinary Licensing Exam (NAVLE) scores were collected on all graduating DVM students at Kansas State University in 2009 and 2010. Associations among the collected data were compared by Pearson correlation. Pre-veterinary admissions criteria infrequently correlated with annual GPAs of Years 1-3, rarely correlated with the AVMA-COE Competencies, and never correlated with the annual GPA of Year 4. Low positive correlations occurred between the NAVLE and the Verbal Graduate Record Examination (GRE) (r=.214), Total GRE (r=.171), and the mean GPA of pre-professional science courses (SGPA) (r=.236). Annual GPAs strongly correlated with didactic course scores. Annual GPAs and final class rank strongly correlated (mean r=-.849), and both strongly correlated with the NAVLE score (NAVLE: GPAs mean r=.628, NAVLE: final class rank r=-.714). Annual GPAs at the end of Years 1-4 weakly correlated or did not correlate with the AVMA-COE Competencies. The AVMA-COE Competencies weakly correlated with scores earned in didactic courses of Years 1-3. AVMA-COE Competencies were internally consistent (mean r=.796) but only moderately correlated with performance on the NAVLE (mean r=.319). Low correlations between admissions criteria and outcomes indicate a need to reevaluate admission criteria as predictors of school success. If the NAVLE remains the primary discriminator for veterinary licensure (and the gateway to professional activity), then the AVMA-COE Competencies should be refined to better improve and reflect the NAVLE, or the NAVLE examination should change to reflect AVMA-COE Competencies. PMID:24152428

  19. Bootstrapped Deattenuated Correlation: Nonnormal Distributions

    ERIC Educational Resources Information Center

    Padilla, Miguel A.; Veprinsky, Anna

    2014-01-01

    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…

  20. Allowing for correlations between correlations in random-effects meta-analysis of correlation matrices.

    PubMed

    Prevost, A Toby; Mason, Dan; Griffin, Simon; Kinmonth, Ann-Louise; Sutton, Stephen; Spiegelhalter, David

    2007-12-01

    Practical meta-analysis of correlation matrices generally ignores covariances (and hence correlations) between correlation estimates. The authors consider various methods for allowing for covariances, including generalized least squares, maximum marginal likelihood, and Bayesian approaches, illustrated using a 6-dimensional response in a series of psychological studies concerning prediction of exercise behavior change. Quantities of interest include the overall population mean correlation matrix, the contrast between the mean correlations, the predicted correlation matrix in a new study, and the conflict between the existing studies and a new correlation matrix. The authors conclude that accounting for correlations between correlations is unnecessary when interested in individual correlations but potentially important if concerned with a composite measure involving 2 or more correlations. A simulation study indicates the asymptotic normal assumption appears reasonable. Because of potential instability in the generalized least squares methods, they recommend a model-based approach, either the maximum marginal likelihood approach or a full Bayesian analysis. PMID:18179354

  1. Single nanowire optical correlator.

    PubMed

    Yu, Huakang; Fang, Wei; Wu, Xiaoqin; Lin, Xing; Tong, Limin; Liu, Weitao; Wang, Aimin; Shen, Y Ron

    2014-06-11

    Integration of miniaturized elements has been a major driving force behind modern photonics. Nanowires have emerged as potential building blocks for compact photonic circuits and devices in nanophotonics. We demonstrate here a single nanowire optical correlator (SNOC) for ultrafast pulse characterization based on imaging of the second harmonic (SH) generated from a cadmium sulfide (CdS) nanowire by counterpropagating guided pulses. The SH spatial image can be readily converted to the temporal profile of the pulses, and only an overall pulse energy of 8 ?J is needed to acquire a clear image of 200 fs pulses. Such a correlator should be easily incorporated into a photonic circuit for future use of on-chip ultrafast optical technology. PMID:24807852

  2. Correlators in nontrivial backgrounds

    SciTech Connect

    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

    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.

  3. Electromagnetic nonuniformly correlated beams.

    PubMed

    Tong, Zhisong; Korotkova, Olga

    2012-10-01

    A class of electromagnetic sources with nonuniformly distributed field correlations is introduced. The conditions on source parameters guaranteeing that the source generates a physical beam are derived. It is shown that the new sources are capable of producing beams with polarization properties that evolve on propagation in a manner much more complex compared to the well-known electromagnetic Gaussian Schell-model beams. PMID:23201663

  4. Correcting correlation function measurements

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    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.

  5. Correlation of advanced glycation endproducts estimated from skin fluorescence in first-degree relatives: the impact of adjustment for skin pigmentation.

    PubMed

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

    2015-03-01

    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

  6. Fecal Calprotectin is an Accurate Tool and Correlated to Seo Index in Prediction of Relapse in Iranian Patients With Ulcerative Colitis

    PubMed Central

    Hosseini, Seyed Vahid; Jafari, Peyman; Taghavi, Seyed Alireza; Safarpour, Ali Reza; Rezaianzadeh, Abbas; Moini, Maryam; Mehrabi, Manoosh

    2015-01-01

    Background: The natural clinical course of Ulcerative Colitis (UC) is characterized by episodes of relapse and remission. Fecal Calprotectin (FC) is a relatively new marker of intestinal inflammation and is an available, non-expensive tool for predicting relapse of quiescent UC. The Seo colitis activity index is a clinical index for assessment of the severity of UC. Objectives: The present study aimed to evaluate the accuracy of FC and the Seo colitis activity index and their correlation in prediction of UC exacerbation. Patients and Methods: In this prospective cohort study, 157 patients with clinical and endoscopic diagnosis of UC selected randomly from 1273 registered patients in Fars province’s IBD registry center in Shiraz, Iran, were followed from October 2012 to October 2013 for 12 months or shorter, if they had a relapse. Two patients left the study before completion and one patient had relapse because of discontinuation of drugs. The participants' clinical and serum factors were evaluated every three months. Furthermore, stool samples were collected at the beginning of study and every three months and FC concentration (commercially available enzyme linked immunoassay) and the Seo Index were assessed. Then univariate analysis, multiple variable logistic regression, Receiver Operating Characteristics (ROC) curve analysis, and Pearson’s correlation test (r) were used for statistical analysis of data. Results: According to the results, 74 patients (48.1%) relapsed during the follow-up (33 men and 41 women). Mean ± SD of FC was 862.82 ± 655.97 ?g/g and 163.19 ± 215.85 ?g/g in relapsing and non-relapsing patients, respectively (P < 0.001). Multiple logistic regression analysis revealed that age, number of previous relapses, FC and the Seo index were significant predictors of relapse. ROC curve analysis of FC level and Seo activity index for prediction of relapse demonstrated area under the curve of 0.882 (P < 0.001) and 0.92 1(P < 0.001), respectively. Besides, FC level of 341 ?g/g was identified as the cut-off point with 11.2% and 79.7% relapse rate below and above this point, respectively. Additionally, Pearson correlation coefficient (r) between FC and the Seo index was significant in prediction of relapse (r = 0.63, P < 0.001). Conclusions: As a simple and noninvasive marker, FC is highly accurate and significantly correlated to the Seo activity index in prediction of relapse in the course of quiescent UC in Iranian patients. PMID:25793117

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

    PubMed Central

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

    2014-01-01

    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

  8. Lack of correlation between microbial penetration method and electro chemical technique for assessment of leakage through the root canal fillings

    PubMed Central

    Kazemipoor, Maryam; Modaresi, Jalil; Zandi, Hengameh; Vasee, Narges; Farzaneh, Vaziri

    2014-01-01

    Aims: The purpose of this study was to compare microbial penetration method and electrochemical technique for evaluation of the apical seal. Materials and Methods: A total of 28 teeth were prepared using the step-back technique to ISO size 40 master apical files. The specimens were randomly divided into an experimental group, two positive and two negative controls. Root canals in the experimental and negative control group were filled with gutta-percha (GP) and sealer, using lateral condensation technique. In the positive control group, canals were filled with GP without any sealer. The external surface of each tooth was coated with two layers of the nail varnish, except for the access opening and the apical foramen. In the negative control group, the teeth were completely covered with nail varnish. The apical seal was recorded with two methods, each successively used on the same teeth: An electrochemical method and a bacterial penetration method. Statistical Analysis Used: The correlation of the electro chemical readings with the results obtained from bacterial micro leakage test was evaluated by Pearson's correlation coefficient. Results: Correlation coefficient of the measurements obtained from the two evaluation methods, was 0.23 (r = 0.23), so the correlation was not statistically significant (P = 0.275). Conclusions: This study shows that several studies by different methods are necessary before evaluation of the marginal leakage. PMID:24808699

  9. Magnitude correlations in global seismicity

    SciTech Connect

    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

    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.

  10. Correlative Measurements Program

    NASA Technical Reports Server (NTRS)

    Parsons, C. L.

    1988-01-01

    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.

  11. Positive Symptoms of Psychosis Correlate With Expression of Ubiquitin Proteasome Genes in Peripheral Blood

    PubMed Central

    Bousman, Chad A.; Chana, Gursharan; Glatt, Stephen J.; Chandler, Sharon D.; May, Todd; Lohr, James; Kremen, William S.; Tsuang, Ming T.; Everall, Ian P.

    2015-01-01

    Several brain- and blood-based gene expression studies in patients with psychotic disorders (e.g., schizophrenia) have identified genes in the ubiquitin proteasome system (UPS) pathway as putative biomarkers. However, to date an examination of the UPS pathway in the broader context of symptom severity in psychosis has not been conducted. The purpose of this study was to investigate the correlation between clinical scores on the Scales for the Assessment of Positive and Negative Symptoms (SAPS–SANS) and expression of 43 highly annotated genes within the UPS pathway in blood from patients with psychosis. A sample of 19 psychotic patients diagnosed with schizophrenia (n = 13) or bipolar disorder (n = 6) were recruited. Pearson's partial correlations, adjusting for gender, ethnicity, age, education, medication, smoking, and past 6-month substance use, were performed between each of the selected UPS genes and both scales. Significant Bonferroni-adjusted positive associations were observed between SAPS scores and two ubiquitin conjugation genes (i.e., UBE2K, SIAH2), while a negative association was observed with one deubiquitination gene (i.e., USP2). No gene expression levels were significantly associated with scores on the SANS after correction for multiple testing. Our findings suggest that dysregulation of the UPS, specifically ubiquitin conjugation and deubiquitination, may point to a possible underlying biological mechanism for severity of positive but not negative symptoms. PMID:20552680

  12. Effect of spatial ability and sex on inter- and intrahemispheric correlation of EEG activity.

    PubMed

    Corsi-Cabrera, M; Arce, C; Ramos, J; Guevara, M A

    1997-01-01

    Inter- and intrahemispheric correlation of the EEG activity at rest was computed in two groups of men and women, between 17 and 21 years old, with extreme degrees of spatial ability (SA) evaluated by the Spatial Relations Subtest of the Differential Aptitudes Test (DAT). Interhemispheric (INTERr) and intrahemispheric (INTRAr) EEG correlations were computed by means of Pearson product-moment coefficients for 5 EEG bands after digitally filtering with an FFT. Women showed significantly higher INTERr of alpha 1 between left and right centrals, lower INTRAr between right frontal and right central regions and lower INTRAr within the left than in the right hemisphere. High SA subjects showed lower INTERr between left and right frontal derivations and higher INTRAr between frontal and parietal and between central and parietal regions of both hemispheres. Sex interacted with SA in INTRAr of alpha between right frontal and right temporal regions with high SA women showing lower INTRAr than low SA women and than men. The present results indicate a different inter- and intrahemispheric functional organization in men and women and in subjects with high and low spatial ability. PMID:9060849

  13. Inter and intrahemispheric EEG correlation as a function of sleep cycles.

    PubMed

    Corsi-Cabrera, M; Guevara, M A; Arce, C; Ramos, J

    1996-04-01

    1. Inter (INTERr) and intrahemispheric (INTRAr) EEG correlation were assessed in 8 young male adults during wakefulness (W) with eyes closed before going to sleep, and during stage 2 (S2), stage 4 (S4) and paradoxical sleep (PS) of the first three sleep cycles during the second night spent at the laboratory. 2. Pearson product-moment correlation were calculated between EEG signals of each pair of electrodes (C3, C4, F3, F4, T3, T4) for every 0.5 Hz from 1.5 to 15 Hz. 3. INTERr and INTRAr of 1.5-6.5 and 11-15 Hz were significantly higher during stage 2 and 4; INTERr of 1.5-6.5 Hz was also higher during PS in cycle 1 and 2, whereas INTERr and INTRAr of 7-10.5 Hz were lower than during wakefulness. 4. INTRAr of S2 and S4 approximated, whereas INTRAr oF PS moved away from W over successive sleep cycles. 5. These data show that cortical changes during sleep are also observed in functional differentiation between cortical sites. Inter and intrahemispheric differentiation is attenuated during stage 2 and 4 while during PS only interhemispheric differentiation is attenuated but intrahemispheric differentiation is accentuated compared to wakefulness. This pattern of cortical differentiation may be of relevance for the understanding of mental activity changes during sleep. PMID:8771596

  14. Asymmetric correlations of equity portfolios

    Microsoft Academic Search

    Andrew Ang; Joseph Chen

    2002-01-01

    Correlations between U.S. stocks and the aggregate U.S. market are much greater for downside moves, especially for extreme downside moves, than for upside moves. We develop a new statistic for measuring, comparing, and testing asymmetries in conditional correlations. Conditional on the downside, correlations in the data differ from the conditional correlations implied by a normal distribution by 11.6%. We find

  15. Correlations between trans-membrane pressure (TMP) and sludge properties in submerged membrane electro-bioreactor (SMEBR) and conventional membrane bioreactor (MBR).

    PubMed

    Hasan, Shadi W; Elektorowicz, Maria; Oleszkiewicz, Jan A

    2012-09-01

    The influence of sludge properties in SMEBR and conventional MBR pilot systems on membrane fouling was investigated. Generated data were analyzed using statistical analysis Pearson's product momentum correlation coefficient (r(p)). Analysis showed that TMP had strong direct (r(p)=0.9182) and inverse (r(p)=-0.9205) correlations to mean particle size diameter in MBR and SMEBR, respectively. TMP in SMEBR had a strong direct correlation to the sludge mixed liquor suspended solids concentration (MLSS) (r(p)=0.7757) while a weak direct correlation (r(p)=0.1940) was observed in MBR. SMEBR showed a moderate inverse correlation (r(p)=-0.6118) between TMP and soluble carbohydrates (EPS(c)) and a very weak direct correlation (r(p)=0.3448) to soluble proteins (EPS(p)). Conversely, EPS(p) in MBR had more significant impact (r(p)=0.4856) on membrane fouling than EPS(c) (r(p)=0.3051). The results provide insight into optimization of operational conditions in SMEBR system to overcome membrane fouling. PMID:22797086

  16. Retinal Blood Vessel Distribution Correlates With the Peripapillary Retinal Nerve Fiber Layer Thickness Profile as Measured With GDx VCC and ECC

    PubMed Central

    Resch, Hemma; Pereira, Ivania; Weber, Stephanie; Holzer, Stephan; Fischer, Georg

    2015-01-01

    Purpose: Aim of the present study was to evaluate whether there is a correlation between retinal blood vessel density (RVD) and the peripapillary retinal nerve fiber layer (RNFL) thickness profile. Methods: RNFL thickness of 106 healthy subjects was measured using scanning laser polarimetry, GDx variable corneal compensation (VCC), and GDx enhanced corneal compensation (ECC). A proprietary software was developed in MATLAB to measure the peripapillary retinal vessels using scanning laser ophthalmoscopy fundus images, centered on the optic disc measured by Cirrus spectral domain optical coherence tomography. The individual retinal vessel positions and thickness values were integrated in a 64-sector RVD profile and intrasubject and intersubject correlations were calculated. Results: The mean R value±SD for intrasubject correlation between RVD and RNFL thickness measured with GDx VCC and GDx ECC was 0.714±0.157 and 0.629±0.140, with 105 of 106 subjects presenting significant correlations. In the intersubject linear regression analysis for GDx VCC, 33 of 64 (52%) sectors presented a significant Pearson correlation coefficient between RNFL thickness and RVD values, with a mean R value of 0.187±0.135 (P<0.05). Conclusions: Peripapillary RNFL thickness profiles correlate with the RVD over 50% of the sectors and might explain up to 26% of the interindividual variance of the peripapillary RNFL thickness values as measured with GDx VCC. To our opinion, taking into account RVD might reduce interindividual variation in peripapillary RNFL thickness profiles measured with scanning laser polarimetry. PMID:25719231

  17. Correlative light-electron microscopy.

    PubMed

    Hanein, Dorit; Volkmann, Niels

    2011-01-01

    Recent advances in combining light and electron microscopy imaging techniques provide the means to correlate dynamic biological processes with the underlying structural correlates in situ. In this chapter, we provide snapshots of current advances targeting quantitative correlation of the dynamic state of a biological pathway with high-resolution structural information in the same window of time and space. PMID:21501820

  18. Digital correlation in photogrammetric instruments

    Microsoft Academic Search

    U. V. Helava

    1978-01-01

    Information on the image power spectrum gives a basis for rational design of digital image correlation systems in that the sampling interval, scanner spot size, and expected sharpness of the correlation function can be estimated. The latter estimate is possible because the correlation function and power spectrum are Fourier transforms of each other. Furthermore, since accuracy is of primary concern

  19. Correlation between National Influenza Surveillance Data and Google Trends in South Korea

    PubMed Central

    Jo, Min Woo; Shin, Soo-Yong; Lee, Jae Ho; Ryoo, Seoung Mok; Kim, Won Young; Seo, Dong-Woo

    2013-01-01

    Background In South Korea, there is currently no syndromic surveillance system using internet search data, including Google Flu Trends. The purpose of this study was to investigate the correlation between national influenza surveillance data and Google Trends in South Korea. Methods Our study was based on a publicly available search engine database, Google Trends, using 12 influenza-related queries, from September 9, 2007 to September 8, 2012. National surveillance data were obtained from the Korea Centers for Disease Control and Prevention (KCDC) influenza-like illness (ILI) and virologic surveillance system. Pearson's correlation coefficients were calculated to compare the national surveillance and the Google Trends data for the overall period and for 5 influenza seasons. Results The correlation coefficient between the KCDC ILI and virologic surveillance data was 0.72 (p<0.05). The highest correlation was between the Google Trends query of H1N1 and the ILI data, with a correlation coefficient of 0.53 (p<0.05), for the overall study period. When compared with the KCDC virologic data, the Google Trends query of bird flu had the highest correlation with a correlation coefficient of 0.93 (p<0.05) in the 2010-11 season. The following queries showed a statistically significant correlation coefficient compared with ILI data for three consecutive seasons: Tamiflu (r?=?0.59, 0.86, 0.90, p<0.05), new flu (r?=?0.64, 0.43, 0.70, p<0.05) and flu (r?=?0.68, 0.43, 0.77, p<0.05). Conclusions In our study, we found that the Google Trends for certain queries using the survey on influenza correlated with national surveillance data in South Korea. The results of this study showed that Google Trends in the Korean language can be used as complementary data for influenza surveillance but was insufficient for the use of predictive models, such as Google Flu Trends. PMID:24339927

  20. Neural correlates of consciousness.

    PubMed

    Negrao, B L; Viljoen, M

    2009-11-01

    A basic understanding of consciousness and its neural correlates is of major importance for all clinicians, especially those involved with patients with altered states of consciousness. In this paper it is shown that consciousness is dependent on the brainstem and thalamus for arousal; that basic cognition is supported by recurrent electrical activity between the cortex and the thalamus at gamma band frequencies; aand that some kind of working memory must, at least fleetingly, be present for awareness to occur. The problem of cognitive binding and the role of attention are briefly addressed and it shown that consciousness depends on a multitude of subconscious processes. Although these processes do not represent consciousness, consciousness cannot exist without them. PMID:20101806

  1. Periodic Ising Correlations

    E-print Network

    Grethe Hystad

    2010-11-09

    In this paper, we first rework B. Kaufman's 1949 paper, "Crystal Statistics. II. Partition Function Evaluated by Spinor Analysis", by using representation theory. Our approach leads to a simpler and more direct way of deriving the spectrum of the transfer matrix for the finite periodic Ising model. We then determine formulas for the spin correlation functions that depend on the matrix elements of the induced rotation associated with the spin operator in a basis of eigenvectors for the transfer matrix. The representation of the spin matrix elements is obtained by considering the spin operator as an intertwining map. We exhibit the "new" elements V+ and V- in the Bugrij-Lisovyy formula as part of a holomorphic factorization of the periodic and anti-periodic summability kernels on the spectral curve associated with the induced rotation for the transfer matrix.

  2. Allowing for Correlations between Correlations in Random-Effects Meta-Analysis of Correlation Matrices

    ERIC Educational Resources Information Center

    Prevost, A. Toby; Mason, Dan; Griffin, Simon; Kinmonth, Ann-Louise; Sutton, Stephen; Spiegelhalter, David

    2007-01-01

    Practical meta-analysis of correlation matrices generally ignores covariances (and hence correlations) between correlation estimates. The authors consider various methods for allowing for covariances, including generalized least squares, maximum marginal likelihood, and Bayesian approaches, illustrated using a 6-dimensional response in a series of…

  3. Expression of mitochondrial transcription factor A in endometrial carcinomas: clinicopathologic correlations and prognostic significance.

    PubMed

    Toki, Naoyuki; Kagami, Seiji; Kurita, Tomoko; Kawagoe, Toshinori; Matsuura, Yusuke; Hachisuga, Toru; Matsuyama, Atsuji; Hashimoto, Hiroshi; Izumi, Hiroto; Kohno, Kimitoshi

    2010-04-01

    Mitochondrial transcription factor A (mtTFA) is necessary for both transcription and maintenance of mitochondrial DNA. This study was conducted to elucidate the clinicopathologic and prognostic significance of mtTFA in patients with endometrial carcinoma. This study investigated the relationship between the immunohistochemical expression of mtTFA and various clinicopathological variables in 276 endometrial carcinomas, including 245 endometrioid adenocarcinomas and 31 nonendometrioid carcinomas (21 serous carcinomas and 10 clear cell adenocarcinomas). Both uni- and multivariate regression analyses were performed. The mtTFA labeling index of endometrioid adenocarcinomas ranged from 0% to 98%, with a median value of 32%, which was selected as the cut-off point for mtTFA expression. The mtTFA expression in endometrioid adenocarcinomas was significantly associated with the surgical stage, myometrial invasion, lymphovascular space invasion, cervical invasion, and lymph node metastasis. In contrast, no correlation between clinicopathologic variables and mtTFA expression was found in nonendometrioid carcinomas. Correlation analysis between mtTFA and p53 expression by using the Pearson test showed significant correlation in endometrioid adenocarcinomas (P = 0.007), but no significant correlation in nonendometrioid carcinomas (P = 0.947). A univariate survival analysis showed that the 10-year overall survival rate of the patients with mtTFA-positive endometrioid adenocarcinoma was significantly worse than that of patients with mtTFA-negative endometrioid adenocarcinoma (80.8% vs. 93.8%, P = 0.012). However, the multivariate analysis revealed that mtTFA expression in endometrioid adenocarcinomas was no independent prognostic factor. The positive mtTFA expression is a useful maker for progression of the tumors and the poor prognosis of the patients in endometrioid adenocarcinomas. PMID:20232213

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

    PubMed

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

    2011-06-01

    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

  5. CORRELATION BETWEEN METAL-CERAMIC BOND STRENGTH AND COEFFICIENT OF LINEAR THERMAL EXPANSION DIFFERENCE

    PubMed Central

    Lopes, Stella Crosara; Pagnano, Valéria Oliveira; Rollo, João Manuel Domingos de Almeida; Leal, Mônica Barbosa; Bezzon, Osvaldo Luiz

    2009-01-01

    The purpose of this study was to evaluate the metal-ceramic bond strength (MCBS) of 6 metal-ceramic pairs (2 Ni-Cr alloys and 1 Pd-Ag alloy with 2 dental ceramics) and correlate the MCBS values with the differences between the coefficients of linear thermal expansion (CTEs) of the metals and ceramics. Verabond (VB) Ni-Cr-Be alloy, Verabond II (VB2), Ni-Cr alloy, Pors-on 4 (P), Pd-Ag alloy, and IPS (I) and Duceram (D) ceramics were used for the MCBS test and dilatometric test. Forty-eight ceramic rings were built around metallic rods (3.0 mm in diameter and 70.0 mm in length) made from the evaluated alloys. The rods were subsequently embedded in gypsum cast in order to perform a tensile load test, which enabled calculating the CMBS. Five specimens (2.0 mm in diameter and 12.0 mm in length) of each material were made for the dilatometric test. The chromel-alumel thermocouple required for the test was welded into the metal test specimens and inserted into the ceramics. ANOVA and Tukey's test revealed significant differences (p=0.01) for the MCBS test results (MPa), with PI showing higher MCBS (67.72) than the other pairs, which did not present any significant differences. The CTE (10-6 °C-1) differences were: VBI (0.54), VBD (1.33), VB2I (-0.14), VB2D (0.63), PI (1.84) and PD (2.62). Pearson's correlation test (r=0.17) was performed to evaluate of correlation between MCBS and CTE differences. Within the limitations of this study and based on the obtained results, there was no correlation between MCBS and CTE differences for the evaluated metal-ceramic pairs. PMID:19274398

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

    PubMed

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

    2014-10-01

    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

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

    SciTech Connect

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

    2009-12-06

    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.

  8. Correlations in -local scenario

    NASA Astrophysics Data System (ADS)

    Mukherjee, Kaushiki; Paul, Biswajit; Sarkar, Debasis

    2015-06-01

    Recently Bell-type inequalities were introduced in Branciard et al. (Phys Rev A 85:032119, 2012) to analyze the correlations emerging in an entanglement swapping scenario characterized by independence of the two sources shared between three parties. The corresponding scenario was referred to as bilocal scenario. Here, we derive Bell-type inequalities in party scenario, i.e., in -local scenario. Considering the two different cases with several number of inputs and outputs, we derive local and -local bounds. The -local inequality studied for two cases are proved to be tight. Replacing the sources by maximally entangled states for two binary inputs and two binary outputs and also for the fixed input and four outputs, we observe quantum violations of -local bounds. But the resistance offered to noise cannot be increased as compared to the bilocal scenario. Thus increasing the number of parties in a linear fashion in source-independent scenario does not contribute in lowering down the requirements of revealing quantumness in a network in contrast to the star configuration (Tavakoli et al. in Phys Rev A 90:062109, 2014) of parties.

  9. SAW correlator spread spectrum receiver

    DOEpatents

    Brocato, Robert W

    2014-04-01

    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.

  10. A Negative Correlation between Human Carotid Atherosclerotic Plaque Progression and Plaque Wall Stress: In Vivo MRI-Based 2D/3D FSI Models

    PubMed Central

    Tang, Dalin; Yang, Chun; Mondal, Sayan; Liu, Fei; Canton, Gador; Hatsukami, Thomas S.; Yuan, Chun

    2008-01-01

    It is well accepted that atherosclerosis initiation and progression correlate positively with low and oscillating flow wall shear stresses (FSS). However, this mechanism cannot explain why advanced plaques continue to grow under elevated FSS conditions. In vivo magnetic resonance imaging (MRI)-based 2D/3D multi-component models with fluid-structure interactions (FSI, 3D only) for human carotid atherosclerotic plaques were introduced to quantify correlations between plaque progression measured by wall thickness increase (WTI) and plaque wall (structure) stress (PWS) conditions. A histologically validated multi-contrast MRI protocol was used to acquire multi-year in vivo MRI images. Our results using 2D models (200–700 data points/patient) indicated that 18 out of 21 patients studied showed significant negative correlation between WTI and PWS at time 2 (T2). The 95% confidence interval for the Pearson correlation coefficient is (?0.443, ?0.246), p < 0.0001. Our 3D FSI model supported the 2D correlation results and further indicated that combining both plaque structure stress and flow shear stress gave better approximation results (PWS, T2: R2 = 0.279; FSS, T1: R2 = 0.276; Combining both: R2 = 0.637). These pilot studies suggest that both lower PWS and lower FSS may contribute to continued plaque progression and should be taken into consideration in future investigations of diseases related to atherosclerosis. PMID:18191138

  11. Clinical Correlates to Laboratory Measures for use in Non-Contact Anterior Cruciate Ligament Injury Risk Prediction Algorithm

    PubMed Central

    Myer, Gregory D.; Ford, Kevin R.; Khoury, Jane; Succop, Paul; Hewett, Timothy E.

    2010-01-01

    Background Prospective measures of high knee abduction moment during landing identify female athletes at high risk for non-contact anterior cruciate ligament injury. Biomechanical laboratory measurements predict high knee abduction moment landing mechanics with high sensitivity (85%) and specificity (93%). The purpose of this study was to identify correlates to laboratory-based predictors of high knee abduction moment for use in a clinic-based anterior cruciate ligament injury risk prediction algorithm. The hypothesis was that clinically obtainable correlates derived from the highly predictive laboratory-based models would demonstrate high accuracy to determine high knee abduction moment status. Methods Female basketball and soccer players (N=744) were tested for anthropometrics, strength and landing biomechanics. Pearson correlation was used to identify clinically feasible correlates and logistic regression to obtain optimal models for high knee abduction moment prediction. Findings Clinical correlates to laboratory-based measures were identified and predicted high knee abduction moment status with 73% sensitivity and 70% specificity. The clinic-based prediction algorithm, including (Odds Ratio: 95% confidence interval) knee valgus motion (1.43:1.30–1.59 cm), knee flexion range of motion (.98:0.96–1.01 deg), body mass (1.04:1.02–1.06 kg), tibia length (1.38:1.25–1.52 cm) and quadriceps to hamstring ratio (1.70:1.06–2.70) predicted high knee abduction moment status with C statistic 0.81. Interpretation The combined correlates of increased knee valgus motion, knee flexion range of motion, body mass, tibia length and quadriceps to hamstrings ratio predict high knee abduction moment status in female athletes with high sensitivity and specificity. PMID:20554101

  12. OA01.25.The first direct experimental evidence correlating ayurveda based tridosha prakriti, with western constitutional psychology somatotypes

    PubMed Central

    Metri, Kashinath G; Bhargav, Hemant; Ramarao, Nagendra Hongasandra; Rizzo-Sierra; Basavakatti, Ramakrishna R

    2012-01-01

    Purpose: Ayurveda is one of the most ancient systems of medical health care. The basic principles, diagnosis of the diseases and their treatment are based on individual prakriti (constitutional type). Ayurveda further classifies the prakriti of an individual on the basis of a set of psychosomatic attributes of personality, depending on whether this individual belongs to Vata, Pitta, or Kapha prakriti, or any combination of them (Patwardhan et al., 2005). The appropriate prakriti assessment is done by several means including questionnaires (Rastogi, 2012; Shilpa and Venkatesha-Murthy, 2011). We aimed to obtain experimental evidence correlating Ayurveda based tridosha-prakriti with western constitutional psychology somatotypes (Rizzo-Sierra, 2011). Method: We employed our Tridosha-prakriti questionnaire (Ramakrishna and Nagendra, 2012), and compared its results with a set of body composition parameters: Height, body weight, body mass index (BMI), muscle mass, fat mass, and fat percentage in normal healthy volunteers (25 males and 25 females, mean age was 26 (± 4) and 25 (± 6) years respectively). Moreover, two-tailed Pearson's correlations were investigated to match the extreme prakriti types with the western constitutional psychology somatotypes, through the mentioned body composition measures. Result: Significant negative correlations were observed between the percentage of Vata attributes as per the questionnaire in the individuals and their BMI, body weight and fat mass respectively (p<0.05). Similarly, there was a significant positive correlation between the percentage of Pitta attributes with the height, body weight, and muscle mass respectively. Also, a significant positive correlation was observed between the percentage of Kapha attributes with fat mass and fat percentage, along with a negative correlation with height. Conclusion: We provide evidence-linking Ayurveda to modern constitutional psychology. In this way, a concept such as prakriti is suggested to lie behind the body mass composition of an individual, and deserves attention within the scientific community.

  13. HMG-CoA reductase expression in primary colorectal cancer correlates with favourable clinicopathological characteristics and an improved clinical outcome

    PubMed Central

    2014-01-01

    Background An association between tumor-specific HMG-CoA reductase (HMGCR) expression and good prognosis has previously been demonstrated in breast and ovarian cancer. In this study, the expression, clinicopathological correlates and prognostic value of HMGCR expression in colorectal cancer was examined. Findings Immunohistochemical expression of HMGCR was assessed in tissue microarrays with primary tumours from 557 incident cases of colorectal cancer in the Malmö Diet and Cancer Study. Pearson’s Chi Square test was applied to explore the associations between HMGCR expression and clinicopathological factors and other investigative biomarkers. Kaplan Meier analysis and Cox proportional hazards modeling were used to assess the relationship between HMGCR expression and cancer-specific survival (CSS) according to negative vs positive HMGCR expression. A total number of 535 (96.0%) tumours were suitable for analysis, of which 61 (11.4%) were HMGCR negative. Positive cytoplasmic HMGCR expression was associated with distant metastasis-free disease at diagnosis (p = 0.002), lack of vascular invasion (p = 0.043), microsatellite-instability (p = 0.033), expression of cyclin D1 (p = <0.001) and p21 (p = <0.001). Positive HMGCR expression was significantly associated with a prolonged CSS in unadjusted Cox regression analysis in the entire cohort (HR = 1.79; 95% CI 1.20-2.66) and in Stage III-IV disease (HR = 1.71; 95% CI 1.09-2.68), but not after adjustment for established clinicopathological parameters. Conclusions Findings from this prospective cohort study demonstrate that HMGCR is differentially expressed in colorectal cancer and that positive expression is associated with favourable tumour characteristics and a prolonged survival in unadjusted analysis. The utility of HMGCR as a predictor of response to neoadjuvant or adjuvant statin treatment in colorectal cancer merits further study. Virtual slides The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2115647072103464. PMID:24708688

  14. Image correlation and sampling study

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

    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.

  15. Improved correlations for retrograde gases

    E-print Network

    Crogh, Arne

    1996-01-01

    for the Niemstschik et al. Correlation. Initial Gas Gravity is 0. 92. Worst case, 42. 3 % absolute average error. . . . . . . . . . . . . . . . 2. 10 Measured versus Calculated Composition for New Correlation. Initial Gas 16 16 17 17 20 20 Gravity is 0. 96.... Best case, 0. 5 % absolute average error. . . . 2. 11 Measured versus Calculated Composition for New Correlation. Initial Gas Gravity is 0. 93. Worst case, 35. 6 % absolute average error. . . . . 3. 1 Calculated and Measured C7+ Molecular...

  16. Correlated Knowledge Gradients: Example alternatives

    E-print Network

    Keinan, Alon

    Correlated Knowledge Gradients: Example -4 -2 0 2 4 alternatives value 0 10 20 30 -10 -8 -6 -4 -2 0;Correlated Knowledge Gradients: Example -4 -2 0 2 4 alternatives value 0 10 20 30 -10 -8 -6 -4 -2 0 num measurements log(KGfactor) 0 10 20 30 0 0.5 1 1.5 2 num measurements opportunitycost #12;Correlated Knowledge

  17. Intergenerational analysis of dietary practices and health perceptions of Hispanic women and their adult daughters.

    PubMed

    Garcia-Maas, L D

    1999-07-01

    This descriptive, correlational, two-group study investigated differences between dietary practices, acculturation, and health perceptions in a convenience sample of Hispanic mothers and their adult daughters (N = 76, 47 mother-daughter dyads). Analysis (paired t tests) of the Block Screening Questionnaire, General Acculturation Index, and Self-Rated Health Subindex of the Multilevel Assessment Instrument showed significant differences: Daughters ate more fat (p = .04) and were more acculturated than their mothers (p = .0001). The Pearson correlation yielded a significant relationship for the 76 subjects between fat intake (dietary practice) and health perception: The more fat (meat/snacks) intake, the more negatively women perceived their health status (p = .0001). PMID:10693408

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

    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.

  19. Lick Galaxy Correlation Function Revised

    E-print Network

    M. Plionis; S. Borgani

    1994-01-21

    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.

  20. Quantum and semiclassical polarization correlations

    E-print Network

    Konrad Banaszek; Rafal Demkowicz-Dobrzanski; Michal Karpinski; Piotr Migdal; Czeslaw Radzewicz

    2009-08-25

    We analyze the strength of polarization correlations between two light beams that can be achieved in the semiclassical regime using statistical mixtures of coherent states and binary on/off detectors. Under certain symmetry assumptions, the visibility of polarization correlations is shown to be bounded by 1/3, which is in a striking contrast with perfect 100% correlations exhibited by photon pairs prepared in the singlet state. The semiclassical limit is demonstrated in a measurement performed on a pair of laser beams undergoing correlated depolarization. This result illustrates the dramatic difference between predictions of quantum mechanics and the semiclassical theory of electromagnetic radiation for the polarization degree of freedom.

  1. Cross-correlation laser scattering.

    PubMed Central

    Kam, Z; Rigler, R

    1982-01-01

    Cross-correlation between two detectors was applied to analyze laser light-scattering fluctuations. Laser scattering from random concentration fluctuations is spatially coherent over small angular areas that are inversely proportional in size to the dimension of the scattering volume. By cross-correlating scattering intensity fluctuations in different angles, the correlation due to relaxation of concentration fluctuations is practically eliminated, and correlations reflecting changes in the scattering from the individual particles can be enhanced. Rotational diffusion of assymetric particles, conformational relaxation of random coils, and association-dissociation dynamics are determined here using the above approach. PMID:7049259

  2. Cross-correlation laser scattering.

    PubMed

    Kam, Z; Rigler, R

    1982-07-01

    Cross-correlation between two detectors was applied to analyze laser light-scattering fluctuations. Laser scattering from random concentration fluctuations is spatially coherent over small angular areas that are inversely proportional in size to the dimension of the scattering volume. By cross-correlating scattering intensity fluctuations in different angles, the correlation due to relaxation of concentration fluctuations is practically eliminated, and correlations reflecting changes in the scattering from the individual particles can be enhanced. Rotational diffusion of assymetric particles, conformational relaxation of random coils, and association-dissociation dynamics are determined here using the above approach. PMID:7049259

  3. Closed sets of nonlocal correlations

    SciTech Connect

    Allcock, Jonathan; Linden, Noah [Department of Mathematics, University of Bristol, Bristol BS8 1TW (United Kingdom); Brunner, Nicolas; Popescu, Sandu; Skrzypczyk, Paul [H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Vertesi, Tamas [Institute of Nuclear Research, Hungarian Academy of Sciences, P.O. Box 51, H-4001 Debrecen (Hungary)

    2009-12-15

    We present a fundamental concept - closed sets of correlations - for studying nonlocal correlations. We argue that sets of correlations corresponding to information-theoretic principles, or more generally to consistent physical theories, must be closed under a natural set of operations. Hence, studying the closure of sets of correlations gives insight into which information-theoretic principles are genuinely different, and which are ultimately equivalent. This concept also has implications for understanding why quantum nonlocality is limited, and for finding constraints on physical theories beyond quantum mechanics.

  4. Digital correlation holograms implemented on a joint transform correlator

    E-print Network

    Rosen, Joseph

    by the Fourier transform phase function. Almost every type of a hologram can be classified accordingDigital correlation holograms implemented on a joint transform correlator David Abookasis, Joseph; accepted 5 August 2003 Abstract A system of two separated computer-generated holograms termed digital

  5. Rank correlation plots for use with correlated input variables

    Microsoft Academic Search

    Ronald L. Iman; James M. Davenport

    1982-01-01

    A method for inducing a desired rank correlation matrix on multivariate input vectors for simulation studies has recently been developed by Iman and Conover (1982). The primary intention of this procedure is to produce correlated input variables for use with computer models. Since this procedure is distribution free and allows the exact marginal distributions to remain intact it can be

  6. EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems

    Microsoft Academic Search

    Filip Ronning; Cristian Batista

    2011-01-01

    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.

  7. Why Are Experts Correlated? Decomposing Correlations between Judges

    ERIC Educational Resources Information Center

    Broomell, Stephen B.; Budescu, David V.

    2009-01-01

    We derive an analytic model of the inter-judge correlation as a function of five underlying parameters. Inter-cue correlation and the number of cues capture our assumptions about the environment, while differentiations between cues, the weights attached to the cues, and (un)reliability describe assumptions about the judges. We study the relative…

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

    PubMed Central

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

    2013-01-01

    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

  9. Coregulation of host-response genes in integument: switchover of gene expression correlation pattern and impaired immune responses induced by dipteran parasite infection in the silkworm, Bombyx mori.

    PubMed

    Jayaram, Anitha; Pradeep, Appukuttan Nair R; Awasthi, Arvind K; Murthy, Geetha N; Ponnuvel, Kangayam M; Sasibhushan, Sirigineedi; Rao, Guruprasad C

    2014-05-01

    The activation of host response proteins against parasitic infection is dependent on the coregulation of immune gene expression. The infection of commercially important silkworm Bombyx mori through endoparasite Exorista bombycis enhanced host-response gene expression in integument early in the infection and was lowered asymptotically. Principal component analysis (PCA) showed heterogeneity while explaining ?80 % variance among expression timings. PCA showed positive and negative correlation with gene expression and differentiated transcriptional timings, and revealed cross talk within the immune system. Pearson correlation analysis showed significant linear correlation (mean R (2)?=?>0.7; P?correlation of five gene pairs including PPAE-Spatzle pair (R (2)?=?0.9; P?correlation with the tyrosine level (R (2)?=?0.410; P?correlated with BmToll expression and negatively correlated with paralytical peptide expression, revealing polygenic influence. Caspase expression was tightly regulated by signal genes in control integument, whereas they were deregulated after infection. Switchover from linear to curvilinear correlation and the appearance of new gene correlations in parasitized integument revealed deviation from gene coregulation, leading to impaired immune responses, characterized by lowered gene expression and varied phenotypic consequences. PMID:24310719

  10. End-Tidal and Arterial Carbon Dioxide Measurements Correlate Across All Levels of Physiologic Dead Space

    PubMed Central

    McSwain, Steven D.; Hamel, Donna S.; Smith, P. Brian; Gentile, Michael A.; Srinivasan, Saumini; Meliones, Jon N.; Cheifetz, Ira M.

    2010-01-01

    Background End-tidal carbon dioxide (ETCO2) is a surrogate, noninvasive measurement of arterial carbon dioxide (PaCO2); however, its clinical applicability in the intensive care unit setting remains unclear. Available research on the relationship between ETCO2 and PaCO2 has not taken a detailed assessment of physiologic dead space into consideration. We hypothesize that ETCO2 reliably predicts PaCO2 across all levels of physiologic dead space provided that the expected ETCO2-PaCO2 gradient is considered. Methods Fifty-six mechanically ventilated pediatric patients (0-17 years; 19.5 ± 24.5 kg) were monitored with volumetric capnography. For every arterial blood gas obtained during routine care, ETCO2 values were collected, and Vd/Vt values calculated. The ETCO2-PaCO2 relationship was assessed by Pearson's correlation coefficients within specified ranges of Vd/Vt. Results Vd/Vt was ? 0.4 for 125 (25%) measurements, 0.41-0.55 for 160 (32%) measurements, 0.55-0.7 for 154 (31%) measurements, and > 0.7 for 54 (11%) measurements. The correlation coefficients between ETCO2 and PaCO2 were 0.95 (mean gradient = 0.3 ± 2.1) for Vd/Vt ? 0.4, 0.88 (mean gradient = 5.9 ± 4.3) for Vd/Vt 0.41-0.55, 0.86 (mean gradient = 13.6 ± 5.2) for Vd/Vt 0.55-0.7, and 0.78 (mean gradient = 17.8 ± 6.7) for Vd/Vt > 0.7. Conclusions Strong correlations between ETCO2 and PaCO2 were found for all Vd/Vt ranges. The ETCO2-PaCO2 gradient increased predictably with increasing Vd/Vt. PMID:20196877

  11. Correlation Weights in Multiple Regression

    ERIC Educational Resources Information Center

    Waller, Niels G.; Jones, Jeff A.

    2010-01-01

    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…

  12. A GENERAL CANONICAL CORRELATION INDEX

    Microsoft Academic Search

    DOUGLAS STEWART; WILLIAM LOVE

    1968-01-01

    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.

  13. Level correlations in integrable systems

    Microsoft Academic Search

    R. A. Serota

    2002-01-01

    We derive a simple analytical expression for the level correlation function of an integrable system. It accounts for both the lack of correlations at smaller energy scales and for global rigidity (level number conservation) at larger scales. We apply our results to a rectangle with incommensurate sides and show that they are in excellent agreement with the limiting cases established

  14. Level Correlations in Integrable Systems

    Microsoft Academic Search

    R. A. Serota

    2002-01-01

    We derive a simple analytical expression for the level correlation function of an integrable system. It accounts for both the lack of correlations at smaller energy scales and for global rigidity (level number conservation) at larger scales. We apply our results to a rectangle with incommensurate sides and show that they are in excellent agreement with the limiting cases established

  15. The Percentage Bend Correlation Coefficient.

    ERIC Educational Resources Information Center

    Wilcox, Rand R.

    1994-01-01

    The percentage bend correlation coefficient is introduced as one way to address the problem that the usual correlation coefficient is highly nonrobust. While this method is not a replacement for the usual test, it can offer advantages in terms of power and Type I errors. (SLD)

  16. Correlated Oxide Physics and Electronics

    NASA Astrophysics Data System (ADS)

    Ngai, J. H.; Walker, F. J.; Ahn, C. H.

    2014-07-01

    Transition metal oxides exhibit a range of correlated phenomena with applications to novel electronic devices that possess remarkable functionalities. This article reviews recent progress in elucidating both mechanisms that govern correlated behavior in transition metal oxides and advancements in device fabrication that have enabled strong correlations to be controlled through applied electric fields. Advancements in the growth of transition-metal-oxide films and artificial heterostructures have enabled superconductivity, magnetism, and metal-insulator transitions to be controlled in cuprates, manganites, and vanadates by using the electric field effect. In addition, interfaces between transition metal oxides have recently emerged as a setting in which strong correlations can be manipulated in two dimensions to realize unusual quantum-ordered phases. Finally, key relationships between structure and transport in ultrathin films of transition metal oxides have been elucidated. Coupling the structural degrees of freedom in oxides to applied electric fields thus opens new pathways to control correlated behavior in devices.

  17. Neural correlates of consciousness reconsidered.

    PubMed

    Neisser, Joseph

    2012-06-01

    It is widely accepted among philosophers that neuroscientists are conducting a search for the neural correlates of consciousness, or NCC. Chalmers (2000) conceptualized this research program as the attempt to correlate the contents of conscious experience with the contents of representations in specific neural populations. A notable claim on behalf of this interpretation is that the neutral language of "correlates" frees us from philosophical disputes over the mind/body relation, allowing the science to move independently. But the experimental paradigms and explanatory canons of neuroscience are not neutral about the mechanical relation between consciousness and the brain. I argue that NCC research is best characterized as an attempt to locate a causally relevant neural mechanism and not as an effort to identify a discrete neural representation, the content of which correlates with some actual experience. It might be said that the first C in "NCC" should stand for "causes" rather than "correlates." PMID:21493099

  18. Wavelet-based morphological correlation

    NASA Astrophysics Data System (ADS)

    Wang, Qu; Chen, Li; Lei, Liang; Wang, Bo

    2010-10-01

    A wavelet-based morphological correlation (WBMC) is proposed as a new architecture to improve the properties of the classical morphological correlation (MC). For the WBMC, a dilated wavelet intensity function is introduced to filter the joint power spectrum (JPS) of the MC before final inverse Fourier transform. Computer simulation results show that, as compared with the linear correlation (LC), the conventional MC and the joint wavelet transform correlation (JWTC), the WBMC provides better discrimination capability with sharp and unmistakable correlation signal and its performance metrics are more stable under input outlier noise (salt-and-pepper noise). Although the WBMC loses illumination-invariance when input illumination factor is larger than unity, considerable discrimination capability is still maintained.

  19. Reliability of Panoramic Radiographs in the Localization of Mandibular Foramen

    PubMed Central

    Patil, Karthikeya; Guledgud, Mahima V

    2015-01-01

    Objective The present study evaluated the reliability and accuracy of panoramic radiographs in the localization of mandibular foramen. Materials and Methods Twenty five Indian dry human adult mandibles constituted the study material. Ten measurements were carried on each of them to evaluate the location of mandibular foramen with respect to adjacent anatomic landmarks. Panoramic radiographs were then made of the mandibles. Same distances were measured on the traced images of the radiographs. Paired t-test and Pearson’s correlation test were applied to evaluate the accuracy and reliability of panoramic radiographs in localization of mandibular foramen. Results The mean distances measured on dry mandibles and panoramic radiographs showed statistically significant difference (p<0.05). There was strong positive correlation between the measurements on dry mandible and panoramic radiographs. Conclusion The panoramic radiographs can serve as a guide in locating the anterosuperior point of mandibular foramen on panoramic radiographs.

  20. Hypercholesterolemia and its correlates in Taiwanese elderly people.

    PubMed Central

    Lin, C. C.; Li, T. C.; Lai, S. W.; Li, C. I.; Tan, C. K.; Ng, K. C.; Lai, M. M.; Liu, C. S.

    1999-01-01

    BACKGROUND: Our study used data collected in Chung-Shing-Shin-Tseun community in Taiwan in May 1998 to evaluate the relationship between hypercholesterolemia and the cardiovascular and sociodemographic risk factors in elderly people. METHODS: Individuals aged 65 and over were recruited as study subjects. A total of 1,093 persons, out of 1,774 registered residents, were contacted in face-to-face interview. The response rate was 61.6 percent. However, only 586 respondents took blood tests and completed questionnaires. Analysis in this study was based on these 586 subjects. The t-test, chi-square analysis, and multivariate logistic regression were used to study the significant correlates of hypercholesterolemia. RESULTS: Our results showed that 66 percent were men and 34 percent were women. The mean age was 73.1 +/- 5.3 years. The mean total cholesterol value was 5.1 +/- 1 mmol/l in elderly men and 5.5 +/- 1.3 mmol/l in elderly women. The proportions of hypercholesterolemia were 43.7 percent in elderly men and 59.6 percent in elderly women. After controlling the other covariates, the multivariate logistic regression analysis showed that the significant related factors of hypercholesterolemia were age, hypertriglyceridemia, and hyperuricemia. No significant association was found between hypercholesterolemia and gender, obesity, high systolic pressure, high diastolic pressure, hyperglycemia, educational level, retirement status, or marital status. CONCLUSION: Hypercholesterolemia is significantly associated with hypertriglyceridemia and hyperuricemia in elderly people. It is important to determine other metabolic disorders if one metabolic disorder is disclosed. PMID:11138933

  1. Structural characteristics and external correlates of the Working Alliance Inventory-Short Form.

    PubMed

    Smits, Dave; Luyckx, Koen; Smits, Dirk; Stinckens, Nele; Claes, Laurence

    2015-06-01

    Controversy remains on the psychometric properties of the Working Alliance Inventory-Short Form (WAI-S). In the present study we first examined the factor structure and reliability of WAI-S scores in a sample of 557 Flemish mental health consumers. Subsequently, we investigated the relationship between early alliance quality and client's psychological dysfunctioning (symptomatic distress, interpersonal functioning and personality pathology). Participants completed the Outcome Questionnaire and the Dimensional Assessment of Personality Pathology-Short Form at start of treatment. The WAI-S was completed after the third treatment session. The structure of the WAI-S was examined using confirmatory factor analysis. Four different factor models were compared. Internal consistencies of the scales were ascertained using the Cronbach's alpha coefficient. Pearson correlations were calculated to determine the relationships between alliance ratings and the independent variables. CFA resulted in a two-factor model, with a Bond component (Contact) and a Task-Goal (Contract) component. Reliability of the WAI-S subscale scores proved to be very good. Symptomatic distress, interpersonal dysfunctioning and personality traits were associated to the Contract component of the alliance, but not to the Contact component. Clinical implications, limitations and suggestions for further research are formulated. (PsycINFO Database Record PMID:25642928

  2. Total Phenytoin concentration is not well correlated with active free drug in critically-ill head trauma patients

    PubMed Central

    Sadeghi, Kourosh; Hadi, Farin; Ahmadi, Arezoo; Hamishehkar, Hadi; Beigmohammadi, Mohammad-Taghi; Mahmoodpoor, Ata; Rouini, Mohammad Reza; Farhudi, Shirin; Hendoui, Narjes; Najafi, Atabak; Mojtahedzadeh, Mojtaba

    2013-01-01

    Objective: Phenytoin is an antiepileptic drug used widely for prophylaxis and treatment of seizure after neurotrauma. Phenytoin has a complex pharmacokinetics and monitoring of its serum concentrations is recommended during treatment. Total phenytoin concentration is routinely measured for monitoring of therapy. In this study, we evaluated the correlation between phenytoin total and free concentrations in neurotrauma critically-ill patients to determine whether the phenytoin total concentration is a reliable predictor of free drug, which is responsible for the therapeutic effects. Methods: A total of 40 adult head trauma patients evaluated for free (unbound) and total serum phenytoin concentrations. Patients were divided into two groups. Group A consists of 20 unconscious patients with severe head injury under mechanical ventilation and Group B consists of 20 conscious self-ventilated patients. Correlation and agreement between total and free phenytoin plasma concentrations were analyzed. Findings: Pearson correlation analysis and Bland-Altman test showed weak to moderate correlation (r = 0.528) and poor agreement between free and total phenytoin concentrations in patients with severe trauma and higher Acute Physiology And Chronic Health Evaluation II (APACHE II) scores (Group A) and good correlation (r = 0.817) and moderate agreement in patients with mild to moderate trauma and lower APACHE II scores (Group B). Conclusion: Our results indicated that total phenytoin serum concentration is not a reliable therapeutic goal for drug monitoring in severely-ill head trauma patients even in the absence of hypoalbuminemia, renal and hepatic failure. It seems justifiable to measure free phenytoin concentration in all severely ill neurotrauma patients. PMID:24991615

  3. Correlation between blood lipid levels and chronic pancreatitis: a retrospective case-control study of 48 cases.

    PubMed

    Ni, Qingqiang; Yun, Lin; Xu, Rui; Shang, Dong

    2014-12-01

    The incidence of chronic pancreatitis (CP) is increasing, and dyslipidemia severely affects the health of middle-aged and elderly people. We investigated the association between blood lipid levels and CP. The serum lipid metabolic indices of 48 patients with CP (CP group) were summarized retrospectively. The physical examination results of 40 randomly selected healthy individuals were used as the normal control (NC) group. Statistical analyses of the blood lipid data were performed between the 2 groups using the case-control study method. High-density lipoprotein-cholesterol (HDL-c) levels decreased and fasting blood glucose (GLU) levels increased in the CP group compared with those in the NC group (P<0.01). Pearson correlation analysis results showed that serum amylase (AMY) was positively correlated with low-density lipoprotein-cholesterol (LDL-c; r=0.414, P<0.05), and urine AMY (UAMY) was positively correlated with total cholesterol (TC; r=0.614, P<0.01) and LDL-c (r=0.678, P<0.01). A binary logistic regression analysis showed that GLU (odds ratio [OR], 5.052; P<0.01) and TC (OR, 1.074; P<0.01) may be risk factors for CP, whereas HDL-c may be a CP protective factor (OR, 0.833; P<0.01). The HDL-c levels decreased and GLU levels increased in the CP group compared with those in the NC group; AMY was positively correlated with LDL-c and UAMY was positively correlated with TC and LDL-c; GLU and TC may be risk factors for CP; and HDL-c may be a CP protective factor. This may be the first time that such results have been reported. These findings will contribute to primary prevention and control of CP progression. PMID:25526493

  4. Correlating multispectral imaging and compositional data from the Mars Exploration Rovers and implications for Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Anderson, Ryan B.; Bell, James F.

    2013-03-01

    In an effort to infer compositional information about distant targets based on multispectral imaging data, we investigated methods of relating Mars Exploration Rover (MER) Pancam multispectral remote sensing observations to in situ alpha particle X-ray spectrometer (APXS)-derived elemental abundances and Mössbauer (MB)-derived abundances of Fe-bearing phases at the MER field sites in Gusev crater and Meridiani Planum. The majority of the partial correlation coefficients between these data sets were not statistically significant. Restricting the targets to those that were abraded by the rock abrasion tool (RAT) led to improved Pearson’s correlations, most notably between the red-blue ratio (673 nm/434 nm) and Fe3+-bearing phases, but partial correlations were not statistically significant. Partial Least Squares (PLS) calculations relating Pancam 11-color visible to near-IR (VNIR; ?400-1000 nm) “spectra” to APXS and Mössbauer element or mineral abundances showed generally poor performance, although the presence of compositional outliers led to improved PLS results for data from Meridiani. When the Meridiani PLS model for pyroxene was tested by predicting the pyroxene content of Gusev targets, the results were poor, indicating that the PLS models for Meridiani are not applicable to data from other sites. Soft Independent Modeling of Class Analogy (SIMCA) classification of Gusev crater data showed mixed results. Of the 24 Gusev test regions of interest (ROIs) with known classes, 11 had >30% of the pixels in the ROI classified correctly, while others were mis-classified or unclassified. k-Means clustering of APXS and Mössbauer data was used to assign Meridiani targets to compositional classes. The clustering-derived classes corresponded to meaningful geologic and/or color unit differences, and SIMCA classification using these classes was somewhat successful, with >30% of pixels correctly classified in 9 of the 11 ROIs with known classes. This work shows that the relationship between SWIR multispectral imaging data and APXS- and Mössbauer-derived composition/mineralogy is often weak, a perhaps not entirely unexpected result given the different surface sampling depths of SWIR imaging (uppermost few microns) vs. APXS (tens of ?m) and MB measurements (hundreds of ?m). Results from the upcoming Mars Science Laboratory (MSL) rover’s ChemCam Laser Induced Breakdown Spectroscopy (LIBS) instrument may show a closer relationship to Mastcam SWIR multispectral observations, however, because the initial laser shots onto a target will analyze only the upper few micrometers of the surface. The clustering and classification methods used in this study can be applied to any data set to formalize the definition of classes and identify targets that do not fit in previously defined classes.

  5. Correlating multispectral imaging and compositional data from the Mars Exploration Rovers and implications for Mars Science Laboratory

    USGS Publications Warehouse

    Anderson, Ryan B.; Bell, James F., III

    2013-01-01

    In an effort to infer compositional information about distant targets based on multispectral imaging data, we investigated methods of relating Mars Exploration Rover (MER) Pancam multispectral remote sensing observations to in situ alpha particle X-ray spectrometer (APXS)-derived elemental abundances and Mössbauer (MB)-derived abundances of Fe-bearing phases at the MER field sites in Gusev crater and Meridiani Planum. The majority of the partial correlation coefficients between these data sets were not statistically significant. Restricting the targets to those that were abraded by the rock abrasion tool (RAT) led to improved Pearson’s correlations, most notably between the red–blue ratio (673 nm/434 nm) and Fe3+-bearing phases, but partial correlations were not statistically significant. Partial Least Squares (PLS) calculations relating Pancam 11-color visible to near-IR (VNIR; ?400–1000 nm) “spectra” to APXS and Mössbauer element or mineral abundances showed generally poor performance, although the presence of compositional outliers led to improved PLS results for data from Meridiani. When the Meridiani PLS model for pyroxene was tested by predicting the pyroxene content of Gusev targets, the results were poor, indicating that the PLS models for Meridiani are not applicable to data from other sites. Soft Independent Modeling of Class Analogy (SIMCA) classification of Gusev crater data showed mixed results. Of the 24 Gusev test regions of interest (ROIs) with known classes, 11 had >30% of the pixels in the ROI classified correctly, while others were mis-classified or unclassified. k-Means clustering of APXS and Mössbauer data was used to assign Meridiani targets to compositional classes. The clustering-derived classes corresponded to meaningful geologic and/or color unit differences, and SIMCA classification using these classes was somewhat successful, with >30% of pixels correctly classified in 9 of the 11 ROIs with known classes. This work shows that the relationship between SWIR multispectral imaging data and APXS- and Mössbauer-derived composition/mineralogy is often weak, a perhaps not entirely unexpected result given the different surface sampling depths of SWIR imaging (uppermost few microns) vs. APXS (tens of ?m) and MB measurements (hundreds of ?m). Results from the upcoming Mars Science Laboratory (MSL) rover’s ChemCam Laser Induced Breakdown Spectroscopy (LIBS) instrument may show a closer relationship to Mastcam SWIR multispectral observations, however, because the initial laser shots onto a target will analyze only the upper few micrometers of the surface. The clustering and classification methods used in this study can be applied to any data set to formalize the definition of classes and identify targets that do not fit in previously defined classes.

  6. Correlation between ocular perfusion pressure and ocular pulse amplitude in glaucoma, ocular hypertension, and normal eyes

    PubMed Central

    Figueiredo, Bruno P; Cronemberger, Sebastião; Kanadani, Fabio N

    2013-01-01

    Background The purpose of this study was to investigate the correlation between ocular perfusion pressure and ocular pulse amplitude in glaucoma, ocular hypertension, and normal eyes. Methods Ninety eyes from 90 patients were included. Thirty patients had been recently diagnosed with glaucoma and had no previous history of treatment for ocular hypotension, 30 had elevated intraocular pressure (IOP) without evidence of glaucoma, and 30 had normal IOP (<21 mmHg) with no detectable glaucomatous damage. Goldmann applanation tonometry (GAT), dynamic contour tonometry (DCT), blood pressure measurement, pachymetry, Humphrey visual field, and routine ophthalmic examination was performed in each patient. Ocular perfusion pressure was calculated as the difference between mean arterial pressure and IOP. The ocular pulse amplitude was given by DCT. The Pearson correlation coefficient was used to compare the glaucomatous and ocular hypertensive groups, and comparisons with the normal IOP group were done using the Spearman’s rank correlation coefficient. Results Mean IOP by DCT was 22.7 ± 4.3 mmHg in the glaucoma group, 22.3 ± 2.8 mmHg in the ocular hypertension group, and 14.3 ± 1.6 mmHg in the control group. Mean IOP by GAT was 19.0 ± 5.1 mmHg for glaucoma, 22.4 ± 2.1 mmHg for ocular hypertension, and 12.9 ± 2.2 mmHg for controls. Mean ocular pulse amplitude was 3.4 ± 1.2 mmHg in the glaucoma group, 3.5 ± 1.2 mmHg in the ocular hypertension group, and 2.6 ± 0.9 mmHg in the control group. Mean ocular perfusion pressure was 46.3 ± 7.9 mmHg in the glaucoma group, 46.3 ± 7.9 mmHg in the ocular hypertension group, and 50.2 ± 7.0 mmHg in controls. No significant correlation between ocular perfusion pressure and ocular pulse amplitude was found in any of the groups (P = 0.865 and r = ?0.032, P = 0.403 and r = ?0.156, P = 0.082 and ? = ?0.307 for glaucoma, ocular hypertension, and normal eyes, respectively). Conclusion There is no significant correlation between ocular perfusion pressure and ocular pulse amplitude values in glaucoma, ocular hypertension, or normal eyes. IOP values measured by GAT correlate with those measured by DCT. PMID:23966769

  7. The Interpretation of Correlation Data.

    E-print Network

    Conner, A. B. (Arthur Benjamin)

    1923-01-01

    classes-genetic and non-genetic. 'he general features of the correlation table are shown and ;ions given of the meaning of different placements of frequency tions in the table, and showing also the possibilities in the I of material where the non-genetic... as to correlation between characters. Ac- cordin~ly, one should be very cautious not to overestimate its value. n the interpretation of pure-line data one can determine with ;y the measure of the non-genetic correlation. From pure-line L,LLGlabion data one may...

  8. Correlation of ascending aorta elasticity and the severity of coronary artery stenosis in hypertensive patients with coronary heart disease assessed by M-mode and tissue Doppler echocardiography.

    PubMed

    Lu, Qixiu; Liu, Houlin

    2015-03-01

    The main objective of this study is to investigate the relationship between ascending aorta elasticity and the severity of coronary artery stenosis in essential hypertensive patients with coronary heart disease (CHD) using M-mode and tissue Doppler echocardiography. A total of 184 hypertensive patients with CHD were enrolled. Patients were divided into three groups based on the severity of coronary stenosis measured by coronary arteriography (CAG): slight stenosis (group 1), moderate stenosis (group 2) and serious stenosis (group 3). M-mode and tissue Doppler echocardiography were performed, and elasticity indexes of ascending aorta including stiffness index, distensibility index, and S wave speed of anterior wall were calculated and correlated with the severity of coronary stenosis. Ascending aorta stiffness index was increased, whereas distensibility index and S wave speed of anterior wall were decreased in moderate and severe stenosis groups compared with slight stenosis group (P < 0.01). Elasticity indexes change in a stepwise pattern with the narrowness of coronary artery, and there was a significant correlation between aortic elasticity and severity of coronary artery by Pearson correlation analysis (P < 0.01). Elasticity indexes of ascending aorta correlate well with severity of coronary stenosis. Elasticity indexes of ascending aorta can serve as predictors for coronary arterial lesion in hypertensive patients. PMID:25269774

  9. Correlations in firm default behavior

    E-print Network

    Thirukkonda, Sreeram (Sreeram Radhakrishnan), 1975-

    2009-01-01

    Modeling credit risk using Structural and Reduced Form models has been a popular and apropos topic of research. This work makes an attempt to better understand correlations in firm default. A review of contemporary research ...

  10. New measure of electron correlation

    E-print Network

    Alex D. Gottlieb; Norbert J. Mauser

    2005-09-15

    We propose to quantify the "correlation" inherent in a many-electron (or many-fermion) wavefunction by comparing it to the unique uncorrelated state that has the same single-particle density operator as it does.

  11. Multiple Correlation versus Multiple Regression.

    ERIC Educational Resources Information Center

    Huberty, Carl J.

    2003-01-01

    Describes differences between multiple correlation analysis (MCA) and multiple regression analysis (MRA), showing how these approaches involve different research questions and study designs, different inferential approaches, different analysis strategies, and different reported information. (SLD)

  12. Frequency-Modulation Correlation Spectrometer

    NASA Technical Reports Server (NTRS)

    Margolis, J. S.; Martonchik, J. V.

    1985-01-01

    New type of correlation spectrometer eliminates need to shift between two cells, one empty and one containing reference gas. Electrooptical phase modulator sinusoidally shift frequencies of sample transmission spectrum.

  13. Doppler integration intervals and correlation

    NASA Astrophysics Data System (ADS)

    Ashkenazi, V.; McLintock, D. N.; Sykes, R. M.

    1980-01-01

    Numerical tests have been carried out to determine the effect of changing the adopted integration time intervals used in the reduction of satellite Doppler data and to establish the contribution of geometrical correlation between adjacent Doppler counts. This has been done by using observational data obtained from a recent United Kingdom Doppler campaign involving 13 primary triangulation stations. Nine different integration intervals were used, ranging from the smallest possible 4.6 s Doppler count to the largest practical interval of 2 min. The tests were carried out for both uncorrelated and correlated Doppler counts. The correlation model used was the standard geometrical correlation pattern for adjacent Doppler counts and range differences. The results of the analysis seem largely to confirm the current mode of practice of using uncorrelated Doppler counts corresponding to time intervals ranging from 20 to 40 s.

  14. Digital correlator with fewer IC's

    NASA Technical Reports Server (NTRS)

    Apple, G. G.; Rubin, L.

    1979-01-01

    Digital correlator requires only few integrated circuits to determine synchronization of two 24-bit digital words. Circuit is easily reduced or expanded to accommodate shorter or longer words and can be utilized in industrial and commercial data processing and telecommunications.

  15. Magnetic correlations and neutron scattering

    Microsoft Academic Search

    W. Marshall; R. D. Lowde

    1968-01-01

    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

  16. Statistical Applets: Correlation and Regression

    NSDL National Science Digital Library

    Created for W.H. Freeman and Co., this applet is designed to help students see correlations in data and see how outliers can affect the correlation and least-squares line. Users can input their own data points and then try to fit a line to the data and see how the sum of squares changed. The user can then also see what the lest-square line is for that set of data.

  17. Level correlations in integrable systems

    Microsoft Academic Search

    R. A. Serota

    2001-01-01

    We derive a simple analytical expression for the level correlation function\\u000aof an integrable system. It accounts for both the lack of correlations at\\u000asmaller energy scales and for global rigidity (level number conservation) at\\u000alarger scales. We apply our results to a rectangle with incommensurate sides\\u000aand show that they are in excellent agreement with the limiting cases\\u000aestablished

  18. Retention capacity of correlated surfaces.

    PubMed

    Schrenk, K J; Araújo, N A M; Ziff, R M; Herrmann, H J

    2014-06-01

    We extend the water retention model [C. L. Knecht et al., Phys. Rev. Lett. 108, 045703 (2012)] to correlated random surfaces. We find that the retention capacity of discrete random landscapes is strongly affected by spatial correlations among the heights. This phenomenon is related to the emergence of power-law scaling in the lake volume distribution. We also solve the uncorrelated case exactly for a small lattice and present bounds on the retention of uncorrelated landscapes. PMID:25019758

  19. Organizational Correlates of Implementation of Colocation of Mental Health and Primary Care in the Veterans Health Administration

    PubMed Central

    Guerrero, Erick G.; Heslin, Kevin C.; Chang, Evelyn; Fenwick, Karissa; Yano, Elizabeth

    2014-01-01

    This study explored the role of organizational factors in the ability of Veterans Health Administration (VHA) clinics to implement colocated mental health care in primary care settings (PC-MH). The study used data from the VHA Clinical Practice Organizational Survey collected in 2007 from 225 clinic administrators across the United States. Clinic degree of implementation of PC-MH was the dependent variable, whereas independent variables included policies and procedures, organizational context, and leaders’ perceptions of barriers to change. Pearson bivariate correlations and multivariable linear regression were used to test hypotheses. Results show that depression care training for primary care providers and clinics’ flexibility and participation were both positively correlated with implementation of PC-MH. However, after accounting for other factors, regressions show that only training primary care providers in depression care was marginally associated with degree of implementation of PC-MH (p = 0.051). Given the importance of this topic for implementing integrated care as part of health care reform, these null findings underscore the need to improve theory and testing of more proximal measures of colocation in future work. PMID:25096986

  20. Organizational correlates of implementation of colocation of mental health and primary care in the veterans health administration.

    PubMed

    Guerrero, Erick G; Heslin, Kevin C; Chang, Evelyn; Fenwick, Karissa; Yano, Elizabeth

    2015-07-01

    This study explored the role of organizational factors in the ability of Veterans Health Administration (VHA) clinics to implement colocated mental health care in primary care settings (PC-MH). The study used data from the VHA Clinical Practice Organizational Survey collected in 2007 from 225 clinic administrators across the United States. Clinic degree of implementation of PC-MH was the dependent variable, whereas independent variables included policies and procedures, organizational context, and leaders' perceptions of barriers to change. Pearson bivariate correlations and multivariable linear regression were used to test hypotheses. Results show that depression care training for primary care providers and clinics' flexibility and participation were both positively correlated with implementation of PC-MH. However, after accounting for other factors, regressions show that only training primary care providers in depression care was marginally associated with degree of implementation of PC-MH (p = 0.051). Given the importance of this topic for implementing integrated care as part of health care reform, these null findings underscore the need to improve theory and testing of more proximal measures of colocation in future work. PMID:25096986

  1. Correlation of echocardiographic epicardial fat thickness with severity of coronary artery disease in patients with acute myocardial infarction.

    PubMed

    Wang, Tao; Liu, Qiang; Liu, Cuixia; Sun, Ling; Li, Daixu; Liu, Aihua; Jia, Ruyi

    2014-11-01

    The aim of this study was to test the hypotheses that epicardial adipose tissue (EAT) can be a marker of severe coronary artery disease in patients with acute myocardial infarction. Overall, 373 cases who underwent coronary angiography were classified into 2 groups by SYNTAX score: low-score and high-score group. EAT was measured by transthoracic echocardiography. Obtained data were compared using Pearson correlation analyses and univariate and multiple logistic regression analysis. The results showed that EAT in the high-score group was significantly greater than in the normal group (5.6 ± 1.1 vs. 4.1 ± 1.0 mm, P < 0.01). EAT had a positive correlation with SYNTAX score (r = 0.61, P < 0.01). Receiver operating characteristic (ROC) curve analyses showed that EAT could reliably discriminate patients with high SYNTAX score (? 33) [AUC: 0.86, 95% confidence interval (CI): 0.822-0.898, P < 0.01]. Multivariate regression analyses showed that EAT was an independent predictor for major in-hospital events. These data showed an association between EAT and SYNTAX score. PMID:24645963

  2. The Murchison Widefield Array Correlator

    NASA Astrophysics Data System (ADS)

    Ord, S. M.; Crosse, B.; 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, N.; 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.; Udaya Shankar, N.; 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.

    2015-03-01

    The Murchison Widefield Array is a Square Kilometre Array Precursor. The telescope is located at the Murchison Radio-astronomy Observatory in Western Australia. The MWA consists of 4 096 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, and others by Graphics Processing Units housed in general purpose rack mounted servers. The correlation capability required is approximately 8 tera floating point operations per second. The MWA has commenced operations and the correlator is generating 8.3 TB day-1 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 processing elements and present the data format for the internal and external interfaces.

  3. Structural modulations in the rare-earth metal digermanides REAl1-xGe2 (RE = Gd-Tm, Lu, Y; 0.8 < x < 0.9). Correlations between long- and short-range vacancy ordering.

    PubMed

    Zhang, Jiliang; Wang, Yingmin; Bobev, Svilen

    2015-02-01

    Rare-earth metal aluminum germanides with the general formula REAl(1-x)Ge(2) (RE = Gd, Tb, Dy, Ho, Er, Tm, Lu, and Y) have been synthesized by direct fusion of the corresponding elements. The structures have been studied by single-crystal X-ray diffraction and selected-area electron diffraction (SAED). The average structure represents a randomly "stuffed" variant of the orthorhombic ZrSi(2) structure type, also known as the CeNi(1-x)Si(2) type (Pearson symbol oC16; space group Cmcm). The SAED patterns for selected members of the family suggest the coexistence of commensurate and incommensurate structural modulations. The most prominent model for long-range vacancy ordering is the Tb(4)FeGe(8) type (Pearson symbol mP26; space group P21/n), which is the commensurate 4-fold superstructure of CeNi(1-x)Si(2) (x = (3)/4). Short-range correlations cause additional deviations in the 4-fold superlattice. These results shed more light on the structural complexity as a function of the aluminum vacancies and size of the rare-earth metal. Magnetic susceptibility measurements are presented and discussed. The measured ordering temperatures and calculated ones based on empirical rules and Ruderman-Kittel-Kasuya-Yosida interactions are shown to be in close agreement. PMID:24964140

  4. Correlation of the interdental and the interradicular bone loss: A radiovisuographic analysis

    PubMed Central

    Grover, Vishakha; Malhotra, Ranjan; Kapoor, Anoop; Mankotia, Chahat Singh; Bither, Rupika

    2014-01-01

    Background: Presence of furcation involvement indicates advanced periodontitis, and a potentially less-favorable prognosis, for the affected tooth and its diagnosis has always been an enigma. The present study was carried out to measure and correlate the interdental and interradicular bone loss in patients suffering from periodontitis using radiovisuography (RVG) for the purpose of early furcation diagnosis. Materials and Methods: A total of 50 patients suffering from chronic generalized periodontitis and with furcation involvement in mandibular molars were selected. Under standardized conditions, RVGs were taken and the morphologic measurements defining the furcation areas were recorded and analyzed. Result: Interradicular bone loss of about 0.8 mm or more, was observed in the study subjects only when the bone loss at the interdental area was minimal of 3.7 mm. The correlation between the interradicular and the interdental bone loss was statistically highly significant (T-test, P < 0.001). A stronger correlation was observed in subjects above 40 years of age as compared with the younger subjects. There was not much difference in the degree of correlation between the interradicular and the interdental bone loss when compared in the context of gender. Conclusion: The very first millimeter of interradicular bone loss was seen when the interdental bone loss was around 4 mm. Therefore, to detect the earliest lesions of furcations, the interdental bone loss can be kept as an approximate guide for the comprehensive diagnosis and management of such sites/patients. The current investigation paves the path for future longitudinal studies with larger samples to ascertain these findings. PMID:25210264

  5. Reliability analysis on PVT correlations

    SciTech Connect

    De Ghetto, G.; Paone, F.; Villa, M.

    1994-12-31

    This paper evaluates the reliability of the most common empirical correlations used for determining reservoir fluid properties whenever laboratory PVT data are not available: bubblepoint pressure, solution GOR, bubblepoint OFVF, isothermal compressibility, dead-oil viscosity, gas-saturated oil viscosity and undersaturated oil viscosity. The reliability of the correlations has been evaluated against a set of 195 crude oil samples collected from the Mediterranean Basin, Africa, the Persian Gulf and the North Sea. About 3700 measured data points have been collected and investigated. All measured data points are reported in the paper. For all the correlations, the following statistical parameters have been calculated: (a) relative deviation between estimated and experimental values, (b) average absolute percent error, (c) standard deviation. Oil samples have been divided into the following four different API gravity classes: extra-heavy oils for {degree}API {le} 10, heavy oils for 10 < {degree}API {le} 22.3, medium oils for 22.3 < {degree}API {le} 31.1, light oils for {degree}API > 31.1. The best correlations both for each class and for the whole range of API gravity have been evaluated for each oil-property. The functional forms of the correlations that gave the best results for each oil property have been used for finding a better correlation with average errors reduced by 5--10%. In particular, for extra-heavy oils, since no correlations are available in literature (except of viscosity), a special investigation has been performed and new equations are proposed.

  6. Correlating gene and protein expression data using Correlated Factor Analysis

    PubMed Central

    Tan, Chuen Seng; Salim, Agus; Ploner, Alexander; Lehtiö, Janne; Chia, Kee Seng; Pawitan, Yudi

    2009-01-01

    Background Joint analysis of transcriptomic and proteomic data taken from the same samples has the potential to elucidate complex biological mechanisms. Most current methods that integrate these datasets allow for the computation of the correlation between a gene and protein but only after a one-to-one matching of genes and proteins is done. However, genes and proteins are connected via biological pathways and their relationship is not necessarily one-to-one. In this paper, we investigate the use of Correlated Factor Analysis (CFA) for modeling the correlation of genome-scale gene and protein data. Unlike existing approaches, CFA considers all possible gene-protein pairs and utilizes all gene and protein information in its modeling framework. The Generalized Singular Value Decomposition (gSVD) is another method which takes into account all available transcriptomic and proteomic data. Comparison is made between CFA and gSVD. Results Our simulation study indicates that the CFA estimates can consistently capture the dominant patterns of correlation between two sets of measurements; in contrast, the gSVD estimates cannot do that. Applied to real cancer data, the list of co-regulated genes and proteins identified by CFA has biologically meaningful interpretation, where both the gene and protein expressions are pointing to the same processes. Among the GO terms for which the genes and proteins are most correlated, we observed blood vessel morphogenesis and development. Conclusion We demonstrate that CFA is a useful tool for gene-protein data integration and modeling, where the main question is in finding which patterns of gene expression are most correlated with protein expression. PMID:19723309

  7. A Correlation Study of Student Attitudes Toward Science in a Southern State High School

    NASA Astrophysics Data System (ADS)

    Barco-Southall, Crystal

    The purpose of this correlational research study was to examine the attitudes toward science of students in Grades 11 and 12 and to investigate if there were differences resulting from gender, grade level, ethnicity, and the level of the curriculum received in average or advanced placement (AP) honors science. The participants of this study consisted of 50 randomly selected male and female high school students who were enrolled in AP and average science classes in an urban Southern state high school. The study used the Test of Science Related Attitudes (TOSRA) instrument to measure students' attitudes toward science in seven categories including (a) Social Implications of Science, (b) Normality of Scientists, (c) Attitude Toward Scientific Inquiry, (d) Adoption of Scientific Attitudes, (e) Enjoyment of Science Lessons, (f) Leisure Interest in Science, and (g) Career Interest in Science. The quantitative component of the study allowed the researcher to determine whether there were gender differences in attitudes toward science based on the seven subscales and measuring different aspects of science attitudes. Statistical treatment of the TOSRA survey involved the use of descriptive statistics, Pearson correlation, and multiple and linear regression. Findings did not reveal significant gender differences on the total attitude scores although there were differences on several of the subscales. In addition, there were no significant differences in the mean attitude scores for grade level. However, the study did reveal differences in ethnicity and attitudes toward science. With regard to ethnicity, scores for Native Americans and Whites were higher than scores for Asians, African Americans, and Hispanics indicating that Native Americans and White students showed a more positive attitude toward science. Regarding the level of curriculum received by students who were exposed to advanced level science courses showed more positive attitudes toward science than those students who were enrolled in average science classes.

  8. Correlations between prognosis and regional biomarker profiles in head and neck squamous cell carcinomas.

    PubMed

    Szentkúti, Gabriella; Dános, Kornél; Brauswetter, Diána; Kiszner, Gerg?; Krenács, Tibor; Csákó, László; Répássy, Gábor; Tamás, László

    2015-07-01

    Head and neck squamous cell carcinomas (HNSCC) show diverse clinicopathological features and are mostly linked with poor outcome. In this study, we tested if the expression of tumor growth, cell cycle and basement membrane anchorage related biomarkers allow prognostic and clinicopathological stratification of HNSCC. Archived HNSCC samples from 226 patients included into tissue microarrays (TMA) were tested using immunohistochemistry. Histopathological evaluation and the analysis of immunostaining for EGFR, Ki67, p53, p16(ink4) and Collagen XVII proteins were carried out in digital whole slides. Statistical evaluation was carried out using Pearson's Chi-square test and Kaplan-Meier survival analysis. In the tested cohort, hypopharyngeal cancers had the least favorable, and glottic cancers had the most favorable prognosis. High Ki67 positive tumor cell fractions were associated with significantly worse prognosis and elevated rate of lymph node metastasis. Both Ki67 and EGFR expression correlated significantly with the tumor localization. Ki67 index was the highest in the hypopharyngeal region and it proved to be the lowest in the glottic region. EGFR expression was the highest in the oral cavity and the lowest in the glottic region. The survival rate of patients with p16(ink4)-negative cancer was significantly lower than of those with p16(ink4)-positive disease. A significant inverse correlation was found between histological grade and the prognosis of HNSCC. Our data support that elevated Ki67 positive proliferating cell fractions contribute to the unfavorable prognosis of hypopharyngeal cancers, while glottic cancers have the most favorable prognosis because of the lowest Ki67 expression rate. PMID:25547827

  9. Retinol-binding protein 4 correlates with triglycerides but not insulin resistance in prepubertal children with and without premature adrenarche

    PubMed Central

    Sopher, Aviva B.; Gerken, Adrienne T.; Lee, Eun-Ju; Blaner, William E.; Deeds, Stefanie; Gallagher, Dympna; Shungu, Dikoma C.; Mao, Xiangling; Hassoun, Abeer; McMahon, Donald J.; Oberfield, Sharon E.

    2013-01-01

    Background Retinol-binding protein 4 (RBP4) has been proposed as an early marker for insulin resistance (IR), but no prior studies have addressed RBP4 in an exclusively prepubertal population. Children with premature adrenarche (PA) are at increased risk for IR and metabolic syndrome (MeS), thus finding an appropriate early marker for IR in this population would allow for early intervention and prevention of morbidity related to IR and MeS. Objective To determine whether prepubertal children with PA have higher levels of RBP4 than controls and whether RBP4 correlates with comorbidities of metabolic disease in prepubertal children. Subjects This study comprised 49 prepubertal children (24 with PA and 25 control subjects), 20 boys and 29 girls, who were between the ages of 5 and 9 years. Methods This was a cross-sectional, case-control study conducted in a subspecialty ambulatory clinic based in a quaternary care center. RBP4 levels, hormonal values, lipids and response to an oral glucose tolerance test were evaluated in children with PA and controls, and body composition measures were obtained in a subset of patients (n=18). Results RBP4 correlated with triglycerides (r = 0.57, P < 0.0001) but did not correlate with IR in a body mass index z-score-adjusted Pearson correlation analysis. There was no difference in RBP4 levels between the PA and control groups. Conclusions These findings suggest that RBP4 may be an early marker of dyslipidemia, which may herald future onset of hepatic IR, polycystic ovary syndrome and MeS. PMID:22145457

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

    PubMed Central

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

    2014-01-01

    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

  11. Biomechanical Properties and Correlation With Collagen Solubility Profile in the Posterior Sclera of Canine Eyes With an ADAMTS10 Mutation

    PubMed Central

    Palko, Joel R.; Iwabe, Simone; Pan, Xueliang; Agarwal, Gunjan; Komáromy, András M.; Liu, Jun

    2013-01-01

    Purpose. We examined the biomechanical properties and correlation with the collagen solubility profile of the posterior sclera in a canine model of primary open-angle glaucoma caused by the G661R missense mutation in the ADAMTS10 gene. Methods. Scleral strips from ADAMTS10-mutant (affected) dogs and age-matched controls were collected. Viscoelastic properties (i.e., complex modulus and tan[?]) were measured using dynamic mechanical analysis (DMA) with a 0.15% sinusoidal strain at different frequencies superimposed upon different preloads. A tensile ramp was performed following DMA. The collagen solubility profile was examined using a colorimetric hydroxyproline assay to determine the amount of soluble and insoluble collagen. The viscoelastic properties were compared between groups using linear mixed models for repeated measures at different preloads and frequencies. The correlation between the biomechanical properties and collagen content were evaluated using Pearson correlations. Results. Complex modulus and tan(?) were significantly lower in the affected group (P < 0.001), and the differences were consistent at different preloads and frequencies. The B value from the tensile ramp test also was significantly lower in the affected group (P = 0.02). The insoluble collagen was significantly lower in the affected group (P < 0.05) and correlated positively with the complex modulus (R = 0.88, P < 0.005). Conclusions. An inherently weaker and biochemically distinct posterior sclera was observed in dogs with the G661R missense mutation in ADAMTS10 before clinical indications of optic nerve damage. It remains to be shown whether and how the altered scleral biomechanics may affect the rate of glaucoma progression following intraocular pressure elevation. PMID:23518772

  12. Neural Correlates of Stimulus Reportability

    PubMed Central

    Hulme, Oliver J.; Friston, Karl F.; Zeki, Semir

    2012-01-01

    Most experiments on the “neural correlates of consciousness” employ stimulus reportability as an operational definition of what is consciously perceived. The interpretation of such experiments therefore depends critically on understanding the neural basis of stimulus reportability. Using a high volume of fMRI data, we investigated the neural correlates of stimulus reportability using a partial report object detection paradigm. Subjects were presented with a random array of circularly arranged disc-stimuli and were cued, after variable delays (following stimulus offset), to report the presence or absence of a disc at the cued location, using variable motor actions. By uncoupling stimulus processing, decision, and motor response, we were able to use signal detection theory to deconstruct the neural basis of stimulus reportability. We show that retinotopically specific responses in the early visual cortex correlate with stimulus processing but not decision or report; a network of parietal/temporal regions correlates with decisions but not stimulus presence, whereas classical motor regions correlate with report. These findings provide a basic framework for understanding the neural basis of stimulus reportability without the theoretical burden of presupposing a relationship between reportability and consciousness. PMID:18823251

  13. Finding Unusual Correlation Using Matrix Decompositions

    Microsoft Academic Search

    David B. Skillicorn

    2004-01-01

    \\u000a One important aspect of terrorism detection is the ability to detect small-scale, local correlations against a background\\u000a of large-scale, diffuse correlations. Several matrix decompositions transform correlation into other properties: for example,\\u000a Singular Value Decomposition (SVD) transforms correlation into proximity, and SemiDiscrete Decomposition (SDD) transforms\\u000a correlation into regions of increased density. Both matrix decompositions are effective at detecting local correlation in

  14. Oscillatory correlates of interference 1 Running head: OSCILLATORY CORRELATES OF INTERFERENCE1

    E-print Network

    van Vugt, Marieke

    Oscillatory correlates of interference 1 Running head: OSCILLATORY CORRELATES OF INTERFERENCE1 Distinct electrophysiological correlates of proactive and similarity-based interference in2 visual working of interference 2 Abstract1 Using scalp electroencephalography, we investigated the oscillatory correlates

  15. Softc: An Operational Software Correlator

    NASA Technical Reports Server (NTRS)

    Lowe, Stephen T.

    2004-01-01

    Softc has been used operationally for spacecraft navigation at JPL for over 2 years and will be JPL's Mark 5 correlator next year. Softc was written to be as close to an ideal correlator as possible, making approximations only below 10(exp -13) seconds. The program can correlate real USB, real LSB, or complex I/Q data sampled with 1, 2, 4. or 8-bit resolution, and was developed with strong debugging tools that made final debugging relatively quick. Softc's algorithms and program structure are fully documented. Timing tests on a recent Intel CPU show Softc processes 8 lags of 1-bit sampled data at 10 MSamples/sec, independent of sample rate.

  16. Angular correlations of galaxy distribution

    E-print Network

    M. Montuori; F. Sylos-Labini

    1997-06-30

    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 $D \\approx 2$.

  17. Spatiotemporal correlations of aftershock sequences

    E-print Network

    Tiago P. Peixoto; Katharina Doblhoff-Dier; Jörn Davidsen

    2010-04-12

    Aftershock sequences are of particular interest in seismic research since they may condition seismic activity in a given region over long time spans. While they are typically identified with periods of enhanced seismic activity after a large earthquake as characterized by the Omori law, our knowledge of the spatiotemporal correlations between events in an aftershock sequence is limited. Here, we study the spatiotemporal correlations of two aftershock sequences form California (Parkfield and Hector Mine) using the recently introduced concept of "recurrent" events. We find that both sequences have very similar properties and that most of them are captured by the space-time epidemic-type aftershock sequence (ETAS) model if one takes into account catalog incompleteness. However, the stochastic model does not capture the spatiotemporal correlations leading to the observed structure of seismicity on small spatial scales.

  18. Spectral lithostratigraphic correlation of boreholes

    NASA Astrophysics Data System (ADS)

    Soaresgalvao, Lenio

    1989-12-01

    The use of spectral radiometry (from 400 to 1000 nm) for lithostratigraphic correlation of rock samples from Parnaiba Basin (Piaui and Maranhao States) boreholes were studied from a quantitative and qualitative standpoint. The former involves the application of the following statistical techniques: cluster analysis, factor analysis, linear discriminant functions and cross-correlations. The effects of chemical composition and of weathering upon the spectral response from stratigraphic units were also investigated. The results indicate the following conclusions: (1) lithostratigraphic correlation between boreholes was successfully done with the use of Mahalanobis' Distance Tests, based on discriminant functions as a measure of similarity among lithological samples; (2) the spectral discrimination of Parnaiba Basin lithologics units was greatly affected by minor rock components, mainly iron and organic matter; and (3) the weathering processes reduce the reflectance values of rock samples, even though it is not known if they significantly affect the spectral separation of rock groups in comparison with the separation of fresh rock material.

  19. Correlated optical and isotopic nanoscopy

    PubMed Central

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

    2014-01-01

    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. PMID:24718107

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

    PubMed

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

    2014-01-01

    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

  1. Top Quark Spin Correlations - Theory

    SciTech Connect

    Parke, Stephen J.; /Fermilab

    2012-02-01

    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].

  2. Correlation properties of loose groups

    SciTech Connect

    Maia, M.A.G.; Da Costa, L.N. (Observatorio Nacional do Brasil, Rio de Janeiro (Brazil))

    1990-02-01

    The two-point spatial correlation function for loose groups of galaxies is computed, using the recently compiled catalog of groups in the southern hemisphere. It is found that the correlation function for groups has a similar slope to that of galaxies but with a smaller amplitude, confirming an earlier result obtained from a similar analysis of the CfA group catalog. This implies that groups of galaxies are more randomly distributed than galaxies, which may be consistent with the predictions of Kashlinsky (1987) for a gravitational clustering scenario for the formation of large-scale structures. 21 refs.

  3. Defect Detection in Correlated Noise

    NASA Astrophysics Data System (ADS)

    Dogandži?, Aleksandar; Eua-Anant, Nawanat

    2004-02-01

    We present methods for detecting NDE defect signals in correlated noise having unknown covariance. The proposed detectors are derived using the statistical theory of generalized likelihood ratio (GLR) tests and multivariate analysis of variance (MANOVA). We consider both real and complex data models. To allow accurate estimation of the noise covariance, we incorporate secondary data containing only noise into detector design. Probability distributions of the GLR test statistics are derived under the null hypothesis, i.e. assuming that the signal is absent, and used for detector design. We apply the proposed methods to simulated and experimental data and demonstrate their superior performance compared with the detectors that neglect noise correlation.

  4. Lack of correlation between tubular dentine cement penetration, adhesiveness and leakage in roots filled with gutta percha and an endodontic cement based on epoxy amine resin

    PubMed Central

    MACHADO, Ricardo; da SILVA NETO, Ulisses Xavier; CARNEIRO, Everdan; FARINIUK, Luiz Fernando; WESTPHALEN, Vânia Portela Ditzel; CUNHA, Rodrigo Sanches

    2014-01-01

    Objective To analyze possible correlations among tubular dentine cement penetration, adhesiveness and apical leakage in fillings performed with gutta percha and an endodontic cement based on epoxy amine resin. Material and Methods Sixty similar, extracted human mandibular central incisors were irrigated, instrumented and filled following the same protocol. First, apical leakage was quantified by fluid filtration tests. Then, these same specimens were sectioned for analysis of tubular dentine cement penetration and the middle thirds were submitted to push-out tests to analyze the adhesiveness of the fillings. Results In brief, the means and standard deviations with a confidence interval of 95% were as follows: tubular dentine cement penetration (8.875±4.540), adhesiveness (4.441±2.683) and apical leakage (0.318±0.215). The data were confronted using the Pearson's test (P>0.05), and it was possible to prove that there was no correlation between (1) tubular dentine cement penetration and apical leakage (r2: 0.08276), (2) tubular dentine cement penetration and adhesiveness (r2: -0.2412) and (3) adhesiveness and apical leakage (r2: 0.1340). Conclusion After analysis of these data, it could be observed that there exists no correlation among the variables analyzed in this study. PMID:24626245

  5. Minor polar compounds in extra virgin olive oil: correlation between HPLC-DAD-MS and the Folin-Ciocalteu spectrophotometric method.

    PubMed

    Alessandri, Stefano; Ieri, Francesca; Romani, Annalisa

    2014-01-29

    Minor polar compounds of 88 extra virgin olive oils were analyzed by HPLC-DAD-MS (high-performance liquid chromatography-diode array detector-mass spectrometry) and by the Folin-Ciocalteu (FC) spectrophotometric method, to validate and evaluate, for olive oils, the linear association between FC and HPLC data. The Pearson correlation coefficients were calculated between HPLC and FC results. The highest, positive R were related with deacetoxyoleuropein aglycone (R = 0.93) and oleuropein aglycone (R = 0.93) as single compounds and with the sum of orthodiphenols (R = 0.94) and the sum of all compounds (R = 0.95), showing that both estimations of total phenols content are reliably correlated, regardless for the absolute contents and are independent of the relative composition of the phenolic fraction. On the other hand the HPLC quantifications of apigenin and lignans showed no significant correlation with FC. These results, supported also by principal component analysis, may suggest caution about the interpretation of FC results to compare olive oils with very different phenolic profiles. PMID:24405086

  6. EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems

    NASA Astrophysics Data System (ADS)

    Ronning, Filip; Batista, Cristian

    2011-03-01

    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

  7. Correlation effects and bound states

    SciTech Connect

    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

    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.

  8. Fashioning Cancer: A Correlation Between

    E-print Network

    Handy, Todd C.

    treatment of Chemotherapy and Radiation when cancer is early in the game. · Every case is different. Cancer? Here were the responses: · "Don't say, `you don't seem sick.'" It was the treatment, not the cancer1 Fashioning Cancer: A Correlation Between Destruction and Beauty Jacqueline Firkins

  9. Improved correlations for retrograde gases 

    E-print Network

    Crogh, Arne

    1996-01-01

    of liquid (FL). Second, a correlation to describe the molar distribution Of C7+ of a gas-condensate mixture as a function of carbon number (CN), the C6 mole fraction and the properties Of C7+ has been developed. For comparison, the Ahmed, et aL, and Whitson...

  10. Biographical Correlates of Vocational Needs.

    ERIC Educational Resources Information Center

    Meresman, Joel

    This research project involves the examination and investigation of the biological correlates of vocational needs. The research attempts to (1) successfully develop a biographical inventory (BI) which can accurately predict vocational needs and (2) extend the construct validity of the Minnesota Importance Questionnaire (MIQ). This paper describes…

  11. Cultural correlates of youth suicide

    Microsoft Academic Search

    Richard Eckersley; Keith Dear

    2002-01-01

    Youth suicide has risen in most developed nations over the past 50 years, especially among males, but the increase remains to be explained. Statistical analyses were used to examine associations between youth suicide rates in 11–21 mainly Western, developed nations and 32 socio-economic and cultural variables. The central hypothesis was that suicide rates would be correlated with various cultural measures

  12. Visual Odometry and Map Correlation

    Microsoft Academic Search

    Anat Levin; Richard Szeliski

    2004-01-01

    In this paper, we study how estimates of ego-motion based on feature tracking (visual odometry) can be im- proved using a rough (low accuracy) map of where the ob- server has been. We call the process of aligning the vi- sual ego-motion with the map locations as map correlation. Since absolute estimates of camera position are unreliable, we use stable

  13. WIDAR Correlator Backend Software Design

    E-print Network

    Groppi, Christopher

    WIDAR Correlator Backend Software Design Martin Pokorny #12;i Revision history Revision Date and console app; added description of pipelinefs to head node soft- ware section. mpp 0.2 19 Sep 2007 Changed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2.1 Compute node pipeline monitor and control interface

  14. Echoes in correlated neural systems

    NASA Astrophysics Data System (ADS)

    Helias, M.; Tetzlaff, T.; Diesmann, M.

    2013-02-01

    Correlations are employed in modern physics to explain microscopic and macroscopic phenomena, like the fractional quantum Hall effect and the Mott insulator state in high temperature superconductors and ultracold atoms. Simultaneously probed neurons in the intact brain reveal correlations between their activity, an important measure to study information processing in the brain that also influences the macroscopic signals of neural activity, like the electroencephalogram (EEG). Networks of spiking neurons differ from most physical systems: the interaction between elements is directed, time delayed, mediated by short pulses and each neuron receives events from thousands of neurons. Even the stationary state of the network cannot be described by equilibrium statistical mechanics. Here we develop a quantitative theory of pairwise correlations in finite-sized random networks of spiking neurons. We derive explicit analytic expressions for the population-averaged cross correlation functions. Our theory explains why the intuitive mean field description fails, how the echo of single action potentials causes an apparent lag of inhibition with respect to excitation and how the size of the network can be scaled while maintaining its dynamical state. Finally, we derive a new criterion for the emergence of collective oscillations from the spectrum of the time-evolution propagator.

  15. Correlated Tunneling in Hydrogen Bonds

    NASA Astrophysics Data System (ADS)

    Lin, Lin; Morrone, Joseph A.; Car, Roberto

    2011-10-01

    We study the quantum nature of the protons participating in hydrogen bonds in several ice structures by analyzing the one particle density matrix. We find that in all cases, including ice Ih, the most common form of ice, and the high pressure phases, ice VIII, VII, and X, the system is ground-state dominated. However, while the dynamics is uncorrelated in the structures with standard asymmetric hydrogen bonds, such as ice Ih and VIII, local correlations among the protons characterize ice VII and, to a lesser extent, ice X in the so-called low barrier hydrogen bond regime. The correlations appear along the path to hydrogen bond symmetrization, when quantum fluctuations delocalize the proton on the two bond sides. The correlations derive from a strong requirement for local charge neutrality that favors concerted motion along the bonds. The resulting behavior deviates substantially from mean field theory, which would predict in ice VII coherent tunneling of the proton between the two bond sides, thereby causing an ionization catastrophe. Due to the correlations, the quantum state of the proton is entangled.

  16. Hadron Correlations and Parton Recombination

    E-print Network

    Rainer J. Fries

    2007-02-08

    Parton recombination has been found to be an extremely useful model to understand hadron production at the Relativistic Heavy Ion Collider. It is particularly important to explore its connections with hard processes. This article reviews some of the aspects of the quark recombination model and places particular emphasis on hadron correlations.

  17. The Decrement of Hemoglobin Concentration with Angiotensin II Receptor Blocker Treatment Is Correlated with the Reduction of Albuminuria in Non-Diabetic Hypertensive Patients: Post-Hoc Analysis of ESPECIAL Trial

    PubMed Central

    An, Jung Nam; Hwang, Jin Ho; Lee, Jung Pyo; Chin, Ho Jun; Kim, Sejoong; Kim, Dong Ki; Kim, Suhnggwon; Park, Jung Hwan; Shin, Sung Joon; Lee, Sang Ho; Choi, Bum Soon; Lim, Chun Soo

    2015-01-01

    Blockade of the renin-angiotensin-aldosterone system exhibits a renoprotective effect; however, blockade of this system may also decrease hemoglobin (Hb) and erythropoietin (EPO) levels. We evaluated the correlation between reduced albuminuria and decreased hemoglobin concentrations after treatment with an angiotensin II receptor blocker (ARB). Two hundred forty-five non-diabetic hypertensive participants with established albuminuria and relatively preserved renal function were treated with an ARB (40 mg/day olmesartan) for eight weeks. Subsequent changes in various clinical parameters, including Hb, EPO, and albuminuria, were analyzed following treatment. After the 8-week treatment with an ARB, Hb and EPO levels significantly decreased. Patients with a greater decrease in Hb exhibited a greater reduction in 24-hour urinary albumin excretion compared with patients with less of a decrease or no decrease in Hb, whereas no associations with a decline in renal function and EPO levels were noted. Multivariate logistic regression analysis demonstrated a correlation between the reduction of urine albumin excretion and the decrease in Hb levels (after natural logarithm transformation, adjusted odds ratio 1.76, 95% confidence interval 1.21-2.56, P = 0.003). Linear regression analysis also supported this positive correlation (Pearson correlation analysis; R = 0.24, P < 0.001). Decreased Hb concentrations following ARB treatment were positively correlated with reduced albuminuria in non-diabetic hypertensive patients, regardless of decreased blood pressure and EPO levels or renal function decline. PMID:26098847

  18. Body adiposity index (BAI) correlates with BMI and body fat pre- and post-bariatric surgery but is not an adequate substitute for BMI in severely obese women

    PubMed Central

    Gibson, C.D.; Atalayer, D.; Flancbaum, L.; Geliebter, A.

    2012-01-01

    Objective Body Adiposity Index (BAI), a new surrogate measure of body fat (hip circumference/[height 1.5–18]), has been proposed as a more accurate alternative to BMI. We compared BAI with BMI and their correlations with measures of body fat, waist circumference (WC), and indirect indices of fat pre- and post-Roux-en-Y gastric bypass (RYGB). Methods Sixteen clinically severe obese (CSO) non-diabetic women (age = 33.9± 7.9 SD; BMI = 46.5±9.5 kg/m2) were assessed pre-surgery, and at 2 (n=9) and 5 mo (n=8) post-surgery. Body fat percentage (% fat) was estimated with bioimpedance analysis (BIA), air displacement plethysmography (ADP), and dual-energy x-ray absorptiometry (DXA). WC, an indicator of central fat, and both plasma leptin (ng/ml) and insulin (mU/l) concentrations were measured as indirect body fat indices. Pre- and post-surgery values were analyzed with Pearson correlations and linear regressions. Results BAI and BMI correlated significantly with each other pre-surgery and at each time point post surgery. BAI and BMI also correlated significantly with % fat from BIA and ADP; however, only BMI correlated significantly with % fat from DXA pre- and post-RYGB. BMI was the single best predictor of WC and leptin at 2 and 5 mo post-surgery and had significant longitudinal changes correlating with % fat from BIA and DXA as well as with leptin. Discussion Both BAI and BMI were good surrogates of % fat as estimated from BIA and ADP, but only BMI was a good surrogate of % fat from DXA in CSO women. Thus, BAI may not be a better alternative to BMI. PMID:23243391

  19. Correlation between HIV viral load and aminotransferases as liver damage markers in HIV infected naive patients: a concordance cross-sectional study.

    PubMed

    Mata-Marín, José Antonio; Gaytán-Martínez, Jesús; Grados-Chavarría, Bernardo Horacio; Fuentes-Allen, José Luis; Arroyo-Anduiza, Carla Ileana; Alfaro-Mejía, Alfredo

    2009-01-01

    Abnormalities in liver function tests could be produced exclusively by direct inflammation in hepatocytes, caused by the human immunodeficiency virus (HIV). Mechanisms by which HIV causes hepatic damage are still unknown. Our aim was to determine the correlation between HIV viral load, and serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) as markers of hepatic damage in HIV naive infected patients. We performed a concordance cross-sectional study. Patients with antiviral treatment experience, hepatotoxic drugs use or co-infection were excluded. We used a Pearson's correlation coefficient to calculate the correlation between aminotransferases serum levels with HIV viral load. We enrolled 59 patients, 50 men and 9 women seen from 2006 to 2008. The mean (+/- SD) age of our subjects was 34.24 +/- 9.5, AST 37.73 +/- 29.94 IU/mL, ALT 43.34 +/- 42.41 IU/mL, HIV viral load 199,243 +/- 292,905 copies/mL, and CD4+ cells count 361 +/- 289 cells/mm(3). There was a moderately strong, positive correlation between AST serum levels and HIV viral load (r = 0.439, P < 0.001); and a weak correlation between ALT serum levels and HIV viral load (r = 0.276, P = 0.034); after adjusting the confounders in lineal regression model the correlation remained significant. Our results suggest that there is an association between HIV viral load and aminotransferases as markers of hepatic damage; we should improved recognition, diagnosis and potential therapy of hepatic damage in HIV infected patients. PMID:19878552

  20. The Correlated Jacobi and the Correlated Cauchy-Lorentz ensembles

    E-print Network

    Tim Wirtz; Daniel Waltner; Mario Kieburg; Santosh Kumar

    2015-05-04

    We calculate the $k$-point generating function of the correlated Jacobi ensemble using supersymmetric methods. We use the result for complex matrices for $k=1$ to derive a closed-form expression for eigenvalue density. For real matrices we obtain the density in terms of a twofold integral that we evaluate numerically. For both expressions we find agreement when comparing with Monte Carlo simulations. Relations between these quantities for the Jacobi and the Cauchy-Lorentz ensemble are derived.

  1. Spatial quantum correlations in multiple scattered light

    E-print Network

    P. Lodahl; A. P. Mosk; A. Lagendijk

    2005-11-10

    We predict a new spatial quantum correlation in light propagating through a multiple scattering random medium. The correlation depends on the quantum state of the light illuminating the medium, is infinite range, and dominates over classical mesoscopic intensity correlations. The spatial quantum correlation is revealed in the quantum fluctuations of the total transmission or reflection through the sample and should be readily observable experimentally.

  2. Discriminant analysis in correlation similarity measure space

    Microsoft Academic Search

    Yong Ma; Shihong Lao; Erina Takikawa; Masato Kawade

    2007-01-01

    Correlation is one of the most widely used similarity measures in machine learning like Euclidean and Mahalanobis distances. However, compared with proposed numerous discriminant learning algorithms in distance metric space, only a very little work has been conducted on this topic using correlation similarity measure. In this paper, we propose a novel discriminant learning algorithm in correlation measure space, Correlation

  3. In Vivo Fluorescence Correlation and Cross-Correlation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Mütze, Jörg; Ohrt, Thomas; Petrášek, Zden?k; Schwille, Petra

    In this manuscript, we describe the application of Fluorescence Correlation Spectroscopy (FCS), Fluorescence Cross-Correlation Spectroscopy (FCCS), and scanning FCS (sFCS) to two in vivo systems. In the first part, we describe the application of two-photon standard and scanning FCS in Caenorhabditis elegans embryos. The differentiation of a single fertilized egg into a complex organism in C. elegans is regulated by a number of protein-dependent processes. The oocyte divides asymmetrically into two daughter cells of different developmental fate. Two of the involved proteins, PAR-2 and NMY-2, are studied. The second investigated system is the mechanism of RNA interference in human cells. An EGFP based cell line that allows to study the dynamics and localization of the RNA-induced silencing complex (RISC) with FCS in vivo is created, which has so far been inaccessible with other experimental methods. Furthermore, Fluorescence Cross-Correlation Spectroscopy is employed to highlight the asymmetric incorporation of labeled siRNAs into RISC.

  4. Respiratory correlated cone beam CT.

    PubMed

    Sonke, Jan-Jakob; Zijp, Lambert; Remeijer, Peter; van Herk, Marcel

    2005-04-01

    A cone beam computed tomography (CBCT) scanner integrated with a linear accelerator is a powerful tool for image guided radiotherapy. Respiratory motion, however, induces artifacts in CBCT, while the respiratory correlated procedures, developed to reduce motion artifacts in axial and helical CT are not suitable for such CBCT scanners. We have developed an alternative respiratory correlated procedure for CBCT and evaluated its performance. This respiratory correlated CBCT procedure consists of retrospective sorting in projection space, yielding subsets of projections that each corresponds to a certain breathing phase. Subsequently, these subsets are reconstructed into a four-dimensional (4D) CBCT dataset. The breathing signal, required for respiratory correlation, was directly extracted from the 2D projection data, removing the need for an additional respiratory monitor system. Due to the reduced number of projections per phase, the contrast-to-noise ratio in a 4D scan reduced by a factor 2.6-3.7 compared to a 3D scan based on all projections. Projection data of a spherical phantom moving with a 3 and 5 s period with and without simulated breathing irregularities were acquired and reconstructed into 3D and 4D CBCT datasets. The positional deviations of the phantoms center of gravity between 4D CBCT and fluoroscopy were small: 0.13 +/- 0.09 mm for the regular motion and 0.39 +/- 0.24 mm for the irregular motion. Motion artifacts, clearly present in the 3D CBCT datasets, were substantially reduced in the 4D datasets, even in the presence of breathing irregularities, such that the shape of the moving structures could be identified more accurately. Moreover, the 4D CBCT dataset provided information on the 3D trajectory of the moving structures, absent in the 3D data. Considerable breathing irregularities, however, substantially reduces the image quality. Data presented for three different lung cancer patients were in line with the results obtained from the phantom study. In conclusion, we have successfully implemented a respiratory correlated CBCT procedure yielding a 4D dataset. With respiratory correlated CBCT on a linear accelerator, the mean position, trajectory, and shape of a moving tumor can be verified just prior to treatment. Such verification reduces respiration induced geometrical uncertainties, enabling safe delivery of 4D radiotherapy such as gated radiotherapy with small margins. PMID:15895601

  5. Respiratory correlated cone beam CT

    SciTech Connect

    Sonke, Jan-Jakob; Zijp, Lambert; Remeijer, Peter; Herk, Marcel van [Department of Radiation Oncology, Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands)

    2005-04-01

    A cone beam computed tomography (CBCT) scanner integrated with a linear accelerator is a powerful tool for image guided radiotherapy. Respiratory motion, however, induces artifacts in CBCT, while the respiratory correlated procedures, developed to reduce motion artifacts in axial and helical CT are not suitable for such CBCT scanners. We have developed an alternative respiratory correlated procedure for CBCT and evaluated its performance. This respiratory correlated CBCT procedure consists of retrospective sorting in projection space, yielding subsets of projections that each corresponds to a certain breathing phase. Subsequently, these subsets are reconstructed into a four-dimensional (4D) CBCT dataset. The breathing signal, required for respiratory correlation, was directly extracted from the 2D projection data, removing the need for an additional respiratory monitor system. Due to the reduced number of projections per phase, the contrast-to-noise ratio in a 4D scan reduced by a factor 2.6-3.7 compared to a 3D scan based on all projections. Projection data of a spherical phantom moving with a 3 and 5 s period with and without simulated breathing irregularities were acquired and reconstructed into 3D and 4D CBCT datasets. The positional deviations of the phantoms center of gravity between 4D CBCT and fluoroscopy were small: 0.13{+-}0.09 mm for the regular motion and 0.39{+-}0.24 mm for the irregular motion. Motion artifacts, clearly present in the 3D CBCT datasets, were substantially reduced in the 4D datasets, even in the presence of breathing irregularities, such that the shape of the moving structures could be identified more accurately. Moreover, the 4D CBCT dataset provided information on the 3D trajectory of the moving structures, absent in the 3D data. Considerable breathing irregularities, however, substantially reduces the image quality. Data presented for three different lung cancer patients were in line with the results obtained from the phantom study. In conclusion, we have successfully implemented a respiratory correlated CBCT procedure yielding a 4D dataset. With respiratory correlated CBCT on a linear accelerator, the mean position, trajectory, and shape of a moving tumor can be verified just prior to treatment. Such verification reduces respiration induced geometrical uncertainties, enabling safe delivery of 4D radiotherapy such as gated radiotherapy with small margins.

  6. Sample Size Tables, "t" Test, and a Prevalent Psychometric Distribution.

    ERIC Educational Resources Information Center

    Sawilowsky, Shlomo S.; Hillman, Stephen B.

    Psychology studies often have low statistical power. Sample size tables, as given by J. Cohen (1988), may be used to increase power, but they are based on Monte Carlo studies of relatively "tame" mathematical distributions, as compared to psychology data sets. In this study, Monte Carlo methods were used to investigate Type I and Type II error…

  7. Correlation between Contingency Allowance and Change Orders

    E-print Network

    Li, Lishan

    2014-08-05

    so that a negative correlation between %Initial Contingency and CPR is highly anticipated. [5] 4.2 Hypothesis of Correlation Analysis %Initial Contingency is negative correlated to CPR; %SA amount and %Premium cost are positively correlated... with CPR. In other words, comparing to supplemental agreement amount and premium cost, initial contingency is rather cost-effective proved by negative correlation between %initial contingency and CPR. 4.3 Data Resources Data analyzed in this paper...

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

    SciTech Connect

    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

    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.

  9. Quantum information of cosmological correlations

    NASA Astrophysics Data System (ADS)

    Lim, Eugene A.

    2015-04-01

    It has been shown that the primordial perturbations sourced by inflation are driven to classicality by unitary evolution alone. However, their coupling with the environment such as photons and subsequent decoherence renders the cosmological correlations quantum, losing primordial information in the process. We argue that the quantumness of the resulting cosmological correlations is given by quantum discord, which captures nonclassical behavior beyond quantum entanglement. By considering the environment as a quantum channel in which primordial information contained in the perturbations is transmitted to us, we can then ask how much of this information is inaccessible. We show that this amount of information is given by the discord of the joint primordial perturbations-environment system. To illustrate these points, we model the joint system as a mixed bimodal Gaussian state, and show that quantum discord is dependent on the basis which decoherence occurs.

  10. A correlated nickelate synaptic transistor

    NASA Astrophysics Data System (ADS)

    Shi, Jian; Ha, Sieu D.; Zhou, You; Schoofs, Frank; Ramanathan, Shriram

    2013-10-01

    Inspired by biological neural systems, neuromorphic devices may open up new computing paradigms to explore cognition, learning and limits of parallel computation. Here we report the demonstration of a synaptic transistor with SmNiO3, a correlated electron system with insulator-metal transition temperature at 130°C in bulk form. Non-volatile resistance and synaptic multilevel analogue states are demonstrated by control over composition in ionic liquid-gated devices on silicon platforms. The extent of the resistance modulation can be dramatically controlled by the film microstructure. By simulating the time difference between postneuron and preneuron spikes as the input parameter of a gate bias voltage pulse, synaptic spike-timing-dependent plasticity learning behaviour is realized. The extreme sensitivity of electrical properties to defects in correlated oxides may make them a particularly suitable class of materials to realize artificial biological circuits that can be operated at and above room temperature and seamlessly integrated into conventional electronic circuits.

  11. Drizzle correlations with giant nuclei

    NASA Astrophysics Data System (ADS)

    Hudson, James G.; Jha, Vandana; Noble, Stephen

    2011-03-01

    Giant nuclei (GN) concentrations (NGN) below RICO small cumulus clouds were substantially correlated with drizzle drop concentrations (Nd), especially at higher cloud altitudes. The NGN-Nd correlation coefficients (R) progressively increased with altitude whereas R for CCN concentrations with Nd were negative with mostly decreasing magnitudes at increasing altitudes. These results indicate that the positive influence of GN [or CCN with low critical supersaturations (Sc)] on Nd is greater than the negative influence of high Sc CCN on Nd at high cloud altitudes where there are more drizzle drops. This work has implications not only for fundamental cloud physics but also for climate change; i.e., global warming and the indirect aerosol effect as well as geoengineering and hygroscopic cloud seeding.

  12. Counterion Correlations on Condensed Biopolymers

    NASA Astrophysics Data System (ADS)

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

    2002-03-01

    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.

  13. Clinicopathologic Correlates of Primary Aldosteronism.

    PubMed

    Duan, Kai; Mete, Ozgur

    2015-07-01

    Primary aldosteronism is the most common cause of secondary hypertension, incurring significant cardiovascular morbidity and mortality. Our understanding of this disease has evolved substantially during the past decade. Recently, the molecular basis of primary aldosteronism has begun to be unraveled, with the discovery of mutations in potassium channel (KCNJ5), ATPases (ATP1A1, ATP2B3), and calcium channel (CACNA1D), and aberrant Wnt/?-catenin signaling. The most recent data suggest that 95% of cases are sporadic, whereas 5% of cases are hereditary. Pathologic correlates of primary aldosteronism include adrenal cortical hyperplasia, adenoma, and carcinoma. Although the most common clinical presentation is bilateral adrenal cortical hyperplasia, this entity is usually treated medically. Therefore, in the setting of primary aldosteronism, surgical pathologists are most commonly exposed to adrenocortical adenomas and the odd occasional carcinoma. This review provides an update on the current knowledge of primary aldosteronism and discusses the clinicopathologic correlations of this important disease. PMID:26125435

  14. Correlations in avalanche critical points.

    PubMed

    Cerruti, Benedetta; Vives, Eduard

    2009-07-01

    Avalanche dynamics and related power-law statistics are ubiquitous in nature, arising in phenomena such as earthquakes, forest fires, and solar flares. Very interestingly, an analogous behavior is associated with many condensed-matter systems, such as ferromagnets and martensites. Bearing it in mind, we study the prototypical random-field Ising model at T=0. We find a finite correlation between waiting intervals and the previous avalanche size. This correlation is not found in other models for avalanches but it is experimentally found in earthquakes and in forest fires. Our study suggests that this effect occurs in critical points that are at the end of a first-order discontinuity separating two regimes: one with high activity from another with low activity. PMID:19658651

  15. CMS results on multijet correlations

    NASA Astrophysics Data System (ADS)

    Safronov, Grigory

    2015-04-01

    We present recent CMS measurements on multijet correlations using forward and low-pT jets, focusing on searches for BFKL and saturation phenomena. In pp collisions at ?{s }=7 TeV, azimuthal correlations in dijets separated in rapidity by up to 9.4 units were measured. The results are compared to BFKL- and DGLAP-based predictions. In pp collisions at ?{s }=8 TeV, cross sections for jets with pT > 21 GeV and |y| < 4.7, and for track-jets with pT > 1 GeV (minijets) are presented. The minijet results are sensitive to the bound imposed by the total inelastic cross section, and are compared to various models for taming the growth of the 2 ? 2 cross section at low pT.

  16. Neuroanatomical correlates of olfactory performance

    Microsoft Academic Search

    Johannes Frasnelli; Johan N. Lundström; Julie A. Boyle; Jelena Djordjevic; Robert J. Zatorre; Marilyn Jones-Gotman

    2010-01-01

    We investigated associations between olfactory function and gray matter thickness in 46 healthy young subjects by means of\\u000a an automated technique for measuring cortical thickness. We used an extended version of the Sniffin’ Sticks test to assess\\u000a olfactory function, including odor threshold, concentration discrimination, quality discrimination, and odor identification.\\u000a We observed a correlation between olfactory performance and cortical thickness of

  17. Neural Correlates of Insight Phenomena

    Microsoft Academic Search

    Jing Luo; Gunther Knoblich; Chongde Lin

    2009-01-01

    Difficult problems are sometimes solved in a sudden flash of illumination, a phenomenon referred to as “insight.” Recent neuroimaging\\u000a studies have begun to reveal the neural correlates of the cognitive processes underlying such insight phenomena (Luo and Niki\\u000a 2003; Jung-Beeman et al. 2004; Luo et al. 2004a, 2006; Mai et al. 2004; Lang et al. 2006). However, researchers have encountered

  18. Dynamical correlation in electron liquids

    Microsoft Academic Search

    Gurinder Singh Atwal

    2002-01-01

    Several aspects of dynamical correlation in electron liquids are considered. First, the dynamic response of an interacting electron system in d-dimensions is determined by an extension of the relaxation-time approximation forced to obey local conservation laws for number, momentum and energy. A consequence of these imposed constraints is that the local electron equilibrium distribution must have a space- and time-dependent

  19. Pair Correlations and Merger Bias

    E-print Network

    Steven R. Furlanetto; Marc Kamionkowski

    2005-11-21

    We study analytically the possibility that mergers of haloes are more highly clustered than the general population of haloes of comparable masses. We begin by investigating predictions for merger bias within the extended Press-Schechter formalism and discuss the limitations and ambiguities of this approach. We then postulate that mergers occur whenever two objects form within a (small) fixed distance of each other. We therefore study the clustering of pairs of points for a highly biased population in the linear regime, for the overall mass distribution in the quasilinear regime, and (using the halo model of clustering) in the nonlinear regime. Biasing, quasilinear evolution, and nonlinear clustering all lead to nonzero reduced (or connected) three-point and four-point correlation functions. These higher-order correlation functions can in many cases enhance the clustering of close pairs of points relative to the clustering of individual points. If close pairs are likely to merge, then the clustering of mergers may be enhanced. We discuss implications for the observed clustering of luminous z=3 galaxies and for correlations of active galactic nuclei and galaxy clusters.

  20. Correlated Temporal and Spectral Variability

    NASA Technical Reports Server (NTRS)

    Swank, Jean H.

    2007-01-01

    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.

  1. Correlative fluorescence and electron microscopy.

    PubMed

    Schirra, Randall T; Zhang, Peijun

    2014-01-01

    Correlative fluorescence and electron microscopy (CFEM) is a multimodal technique that combines dynamic and localization information from fluorescence methods with ultrastructural data from electron microscopy, to give new information about how cellular components change relative to the spatiotemporal dynamics within their environment. In this review, we will discuss some of the basic techniques and tools of the trade for utilizing this attractive research method, which is becoming a very powerful tool for biology labs. The information obtained from correlative methods has proven to be invaluable in creating consensus between the two types of microscopy, extending the capability of each, and cutting the time and expense associated with using each method separately for comparative analysis. The realization of the advantages of these methods in cell biology has led to rapid improvement in the protocols and has ushered in a new generation of instruments to reach the next level of correlation-integration. Curr. Protoc. Cytom. 70:12.36.1-12.36.10. © 2014 by John Wiley & Sons, Inc. PMID:25271959

  2. The Effect of Error Correlation on Interfactor Correlation in Psychometric Measurement

    ERIC Educational Resources Information Center

    Westfall, Peter H.; Henning, Kevin S. S.; Howell, Roy D.

    2012-01-01

    This article shows how interfactor correlation is affected by error correlations. Theoretical and practical justifications for error correlations are given, and a new equivalence class of models is presented to explain the relationship between interfactor correlation and error correlations. The class allows simple, parsimonious modeling of error…

  3. A Two Factor ANOVA-like Test for Correlated Correlations: CORANOVA

    ERIC Educational Resources Information Center

    Bilker, Warren B.; Brensinger, Colleen; Gur, Ruben C.

    2004-01-01

    Testing homogeneity of correlations with Fisher's Z is inappropriate when correlations are themselves correlated. Suppose measurements of brain activation and performance are taken before and during a verbal memory task. Of interest are changes in activity gradients in specific regions, R1, R2, R3, and performance, V. The "correlated correlations"…

  4. Electromyographic indices, orofacial myofunctional status and temporomandibular disorders severity: A correlation study.

    PubMed

    De Felício, Cláudia Maria; Ferreira, Cláudia Lúcia Pimenta; Medeiros, Ana Paula Magalhães; Rodrigues Da Silva, Marco Antonio M; Tartaglia, Gianluca M; Sforza, Chiarella

    2012-04-01

    This study examined whether there is an association between surface electromyography (EMG) of masticatory muscles, orofacial myofunction status and temporomandibular disorder (TMD) severity scores. Forty-two women with TMD (mean 30 years, SD 8) and 18 healthy women (mean 26 years, SD 6) were examined. According to the Research Diagnostic Criteria for TMD (RDC/TMD), all patients had myogenous disorders plus disk displacements with reduction. Surface EMG of masseter and temporal muscles was performed during maximum teeth clenching either on cotton rolls or in intercuspal position. Standardized EMG indices were obtained. Validated protocols were used to determine the perception severity of TMD and to assess orofacial myofunctional status. TMD patients showed more asymmetry between right and left muscle pairs, and more unbalanced contractile activities of contralateral masseter and temporal muscles (p<0.05, t-test), worse orofacial myofunction status and higher TMD severity scores (p<0.05, Mann-Whitney test) than healthy subjects. Spearman coefficient revealed significant correlations between EMG indices, orofacial myofunctional status and TMD severity (p<0.05). In conclusion, these methods will provide useful information for TMD diagnosis and future therapeutic planning. PMID:22206640

  5. Prospective Study Validating Inter- and Intraobserver Variability of Tissue Compliance Meter in Breast Tissue of Healthy Volunteers: Potential Implications for Patients With Radiation-Induced Fibrosis of the Breast

    SciTech Connect

    Wernicke, A. Gabriella, E-mail: gaw9008@med.cornell.ed [Stich Radiation Oncology, Weill Cornell Medical College of Cornell University, New York, NY (United States); Parashar, Bhupesh; Kulidzhanov, Fridon; Riley, Lillian [Stich Radiation Oncology, Weill Cornell Medical College of Cornell University, New York, NY (United States); Christos, Paul J. [Division of Biostatistics and Epidemiology, Department of Public Health, Weill Cornell Medical College of Cornell University, New York, NY (United States); Fischer, Andrew [Physical Medicine and Rehabilitation, Mount Sinai School of Medicine, New York, NY (United States); Nori, Dattatreyudu; Chao, K.S. Clifford [Stich Radiation Oncology, Weill Cornell Medical College of Cornell University, New York, NY (United States)

    2011-05-01

    Purpose: Accurate detection of radiation-induced fibrosis (RIF) is crucial in management of breast cancer survivors. Tissue compliance meter (TCM) has been validated in musculature. We validate TCM in healthy breast tissue with respect to interobserver and intraobserver variability before applying it in RIF. Methods and Materials: Three medical professionals obtained three consecutive TCM measurements in each of the four quadrants of the right and left breasts of 40 women with no breast disease or surgical intervention. The intraclass correlation coefficient (ICC) assessed interobserver variability. The paired t test and Pearson correlation coefficient (r) were used to assess intraobserver variability within each rater. Results: The median age was 45 years (range, 24-68 years). The median bra size was 35C (range, 32A-40DD). Of the participants, 27 were white (67%), 4 black (10%), 5 Asian (13%), and 4 Hispanic (10%). ICCs indicated excellent interrater reliability (low interobserver variability) among the three raters, by breast and quadrant (all ICC {>=}0.99). The paired t test and Pearson correlation coefficient both indicated low intraobserver variability within each rater (right vs. left breast), stratified by quadrant (all r{>=} 0.94, p < 0.0001). Conclusions: The interobserver and intraobserver variability is small using TCM in healthy mammary tissue. We are now embarking on a prospective study using TCM in women with breast cancer at risk of developing RIF that may guide early detection, timely therapeutic intervention, and assessment of success of therapy for RIF.

  6. Residential characteristics as correlates of occupants’ health in the greater Accra region, Ghana

    PubMed Central

    2014-01-01

    Background Housing has been a relatively neglected site for public health action. However, it remains a place where human beings spend the most part of their day. As a result, the quality of housing has consequences for human health. We investigate residential characteristics associated with self-rated occupant health in five neighbourhoods in the Greater Accra Region, Ghana. Methods A cross sectional study using a semi-structured questionnaire was conducted among 500 informed adults aged 18 years and above to investigate residential characteristics associated with self-rated occupant health in five neighbourhoods in the Greater Accra Region, Ghana. Correlates of occupant rated health were determined using Pearson chi-square test and binary logistic regression. Results Forty-two per cent of houses were rented, 44% required repair and 46% shared sanitation facilities. One in twenty occupants reported poor health. Gender, employment status, income, ventilation, house wall material, odours, stale air, privacy, shared facilities, hand washing facility, type of house and house repair status were associated with poor health in the bivariate analysis. Only two variables were independently associated with poor self-rated health: occupants who lacked privacy were eight times more likely to report poor self-rated health when compared to peers who did not lack privacy [OR = 8.16, 95% CI 2.86-23.26] and women were three times more likely than men to report poor health [OR = 2.98, 95% CI 1.06-8.35]. Conclusion The results provide further evidence of housing as a determinant of occupants’ health, and identify housing characteristics and living conditions as issues for public health action in Ghana. PMID:24612884

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

    PubMed

    Cipro, Caio V Z; Yogui, Gilvan Takeshi; Bustamante, Paco; Taniguchi, Satie; Sericano, José L; Montone, Rosalinda Carmela

    2011-10-01

    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

  8. Correlations between subjective treatment responses and plantar pressure parameters of metatarsal pad treatment in metatarsalgia patients: a prospective study

    PubMed Central

    Kang, Jiunn-Horng; Chen, Min-Der; Chen, Shih-Ching; Hsi, Wei-Li

    2006-01-01

    Background Metatarsalgia is related to repetitive high-pressure loading under the metatarsal head (MH) that causes pain. The high pressure under the MH can be reduced by adequately applying metatarsal pads (MPs). Plantar pressure measurements may provide a method to objectively evaluate pressure loading under the MH. However, it is still unclear if the decrease in plantar pressure under the MH after MP treatment is associated with subjective improvement. This study aims to explore the correlations between subjective pain improvement and outcome rating, and the plantar pressure parameters in metatarsalgia patients treated using MPs. Methods Thirteen patients (a total of 18 feet) with secondary metatarsalgia were included in this study. Teardrop-shaped MPs made of polyurethane foam were applied just proximal to the second MH by an experienced physiatrist. Insole plantar pressure was measured under the second MH before and after MP application. Visual analog scale (VAS) scores of pain were obtained from all subjects before and after 2 weeks of MP treatment. The subjects rated using four-point subjective outcome scales. The Wilcoxon signed-rank test was used to analyze the difference between the plantar pressure parameters and VAS scores before and after treatment. The Kruskal-Wallis test was applied to compare the plantar pressure parameters in each outcome group. Pearson's correlation was applied to analyze the correlation between the changes in plantar pressure parameters and VAS scores. Statistical significance was set as p < 0.05. Results MP application decreased the maximal peak pressure (MPP) and pressure-time integral (PTI) under the second MH and also statistically improved subjective pain scores. However, neither the pre-treatment values of the MPP and PTI shift in the position of the MPP after treatment, nor the age, gender and body mass index (BMI) of the subjects were statistically correlated with subjective improvement. Declines in the PTI and MPP values after MP application were statistically correlated with the improvement in VAS scores (r = 0.77, R2 = 0.59, p < 0.001; r = 0.60, R2 = 0.36, p = 0.009). Conclusion We found that the successful decline in the PTI and MPP under the second MH after MP application was correlated to subjective pain improvement. This study provides a strategy for the further design and application of MPs for metatarsalgia treatment. PMID:17147793

  9. THOMAS W. PEARSON University of WisconsinStout

    E-print Network

    Wu, Mingshen

    an afternoon workshop on the risks posed by genetically modified seeds, known popularly in Central America. Scientists genetically modify organisms by transferring genetic mate- rial between two unlike species in numerous countries oppose transgenic seeds and foods, citing concerns about envi- ronmental and health

  10. 2005 Pearson Education South Asia Pte Ltd Applied Fluid Mechanics

    E-print Network

    Leu, Tzong-Shyng "Jeremy"

    Sections 10.Minor Losses 11.Series Pipeline Systems 12.Parallel Pipeline Systems 13.Pump Selection. Compute the resultant force exerted on any submerged plane area by a static liquid. 6. Show the vector representing the resultant force on any submerged plane area in its proper location and direction. #12;3 4

  11. HelenPearson,NewYork Africa should pursue agricultural research

    E-print Network

    Cai, Long

    Cyranoski,Tokyo Japan looks set to end its bar on therapeutic cloning, giving it the chance to compete with Britain, the bioethics committee of the Council for Science and Technology Policy,Japan's main scientific decision- making body, voted to lift a three-year moratorium on therapeutic cloning by ten votes to five.The main

  12. MARKARIAN 501 MONITORING CAMPAIGN USING ROVOR Richard L. Pearson III

    E-print Network

    Hart, Gus

    hole within Mk501. No periodic behavior was identified, but intranight variations occurred daily. SBP . . . . . . . . . . . . . . . . . . . . . . . . 10 2.2.3 Weather Station . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3 Reduction

  13. 2015 Pearson Education, Inc. Chapter 7 Water and Atmospheric Moisture

    E-print Network

    Pan, Feifei

    Education, Inc. Learning Objectives · Describe the heat properties of water, and identify the three phases, and stable--with a simple graph that relates the environmental lapse rate (ELR) to the dry adiabatic rate-oxygen-laden debris. · Outgassing is a process by which water and water vapor emerge from layers deep within and below

  14. 2005 Pearson Education Inc., publishing as Addison-Wesley

    E-print Network

    Shirley, Yancy

    , a bunch of dead white guys, but 2500 years ago they came up with: · Philosophy, logic, the scientific · Geometry, algebra, infinity, irrational numbers · Ideas of the round Earth, heliocentric universe WOW! #12

  15. 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...

  16. 2005 Pearson Education South Asia Pte Ltd Applied Fluid Mechanics

    E-print Network

    Leu, Tzong-Shyng "Jeremy"

    Sections 10.Minor Losses 11.Series Pipeline Systems 12.Parallel Pipeline Systems 13.Pump Selection is not circular. · An example is the shell-and-tube heat exchanger shown in Fig. 9.1, in which, for example, hot water from an industrial process may be flowing to the right inside the inner tube. #12;4 9. Velocity

  17. HelenPearson A study highlighting statistical gaffes in

    E-print Network

    García-Berthou, Emili

    cloned a human somatic cell, creating an embryo that they used to establish a stem-cell line thera- peutic human embryonic cloning research," readsthestatementtheyissued. The questions, postedCyranoski,Tokyo Bioethicists are pushing for an investigation into the cloning work of a South Korean research team

  18. 2005 Pearson Education South Asia Pte Ltd Applied Fluid Mechanics

    E-print Network

    Leu, Tzong-Shyng "Jeremy"

    .1 Introductory Concepts · The buoy and the ship are obviously designed to float. · The diving bell would tend to sink unless supported by the cable from the crane on the ship. · Consider any kind of boat, raft, or other floating object that is expected to maintain a particular orientation when placed in a fluid. 5

  19. Exercising calf muscle changes correlate with pH, PCr recovery and maximum oxidative phosphorylation

    PubMed Central

    Schmid, Albrecht Ingo; Schewzow, Kiril; Fiedler, Georg Bernd; Goluch, Sigrun; Laistler, Elmar; Wolzt, Michael; Moser, Ewald; Meyerspeer, Martin

    2014-01-01

    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

  20. Variable Selection through Correlation Sifting

    NASA Astrophysics Data System (ADS)

    Huang, Jim C.; Jojic, Nebojsa

    Many applications of computational biology require a variable selection procedure to sift through a large number of input variables and select some smaller number that influence a target variable of interest. For example, in virology, only some small number of viral protein fragments influence the nature of the immune response during viral infection. Due to the large number of variables to be considered, a brute-force search for the subset of variables is in general intractable. To approximate this, methods based on ?1-regularized linear regression have been proposed and have been found to be particularly successful. It is well understood however that such methods fail to choose the correct subset of variables if these are highly correlated with other "decoy" variables. We present a method for sifting through sets of highly correlated variables which leads to higher accuracy in selecting the correct variables. The main innovation is a filtering step that reduces correlations among variables to be selected, making the ?1-regularization effective for datasets on which many methods for variable selection fail. The filtering step changes both the values of the predictor variables and output values by projections onto components obtained through a computationally-inexpensive principal components analysis. In this paper we demonstrate the usefulness of our method on synthetic datasets and on novel applications in virology. These include HIV viral load analysis based on patients' HIV sequences and immune types, as well as the analysis of seasonal variation in influenza death rates based on the regions of the influenza genome that undergo diversifying selection in the previous season.

  1. The crystallography of correlated disorder.

    PubMed

    Keen, David A; Goodwin, Andrew L

    2015-05-21

    Classical crystallography can determine structures as complicated as multi-component ribosomal assemblies with atomic resolution, but is inadequate for disordered systems--even those as simple as water ice--that occupy the complex middle ground between liquid-like randomness and crystalline periodic order. Correlated disorder nevertheless has clear crystallographic signatures that map to the type of disorder, irrespective of the underlying physical or chemical interactions and material involved. This mapping hints at a common language for disordered states that will help us to understand, control and exploit the disorder responsible for many interesting physical properties. PMID:25993960

  2. Quantum correlations and mutual synchronization

    E-print Network

    Giorgi, Gian Luca; Manzano, Gonzalo; Colet, Pere; Zambrini, Roberta

    2011-01-01

    We consider the phenomenon of mutual synchronization in a fundamental quantum system, two detuned quantum harmonic oscillators dissipating into the environment. We identify the conditions leading to this spontaneous phenomenon and show that different oscillators synchronize only for a common thermal bath and in a range of frequencies detunings and couplings, but not for separate baths. We then consider synchronization within a quantum information perspective analyzing the time evolution of quantum discord and mutual information. We show that the ability of the system to synchronize is accompanied by robust correlations between the oscillators, preventing the leak of both classical and quantum information from the system.

  3. Post-correlation RFI detection

    NASA Astrophysics Data System (ADS)

    Offringa, A. R.; de Bruyn, A. G.; Zaroubi, S.; Biehl, M.

    2010-05-01

    Radio astronomy is entering a new era with new and future radio observatories such as the Low-Frequency Array and the Square Kilometer Array. We describe in detail an automated flagging pipeline and evaluate its performance. With only a fraction of the computational cost of correlation and its use of the previously introduced SumThreshold method, it is found to be both fast and unrivalled in its high accuracy. The LOFAR radio environment is analysed with the help of this pipeline. The high time and spectral resolution of LOFAR have resulted in an observatory where only a few percent of the data is lost due to RFI.

  4. Postulates for measures of genuine multipartite correlations

    SciTech Connect

    Bennett, Charles H. [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Grudka, Andrzej [Institute of Theoretical Physics and Astrophysics, University of Gdansk, PL-80-952 Gdansk (Poland); Faculty of Physics, Adam Mickiewicz University, PL-61-614 Poznan (Poland); Horodecki, Michal; Horodecki, Ryszard [Institute of Theoretical Physics and Astrophysics, University of Gdansk, PL-80-952 Gdansk (Poland); Horodecki, Pawel [Faculty of Applied Physics and Mathematics, Technical University of Gdansk, PL-80-952 Gdansk (Poland)

    2011-01-15

    A lot of research has been done on multipartite correlations, but the problem of satisfactorily defining genuine multipartite correlations--those not trivially reducible to lower partite correlations--remains unsolved. In this paper we propose three reasonable postulates which each measure or indicator of genuine multipartite correlations (or genuine multipartite entanglement) should satisfy. We also introduce the concept of degree of correlations, which gives partial characterization of multipartite correlations. Then, we show that covariance does not satisfy two postulates and hence it cannot be used as an indicator of genuine multipartite correlations. Finally, we propose a candidate for a measure of genuine multipartite correlations based on the work that can be drawn from a local heat bath by means of a multipartite state.

  5. Directional Correlation of Successive Nuclear Radiations

    Microsoft Academic Search

    Giulio Racah

    1951-01-01

    Using the algebra of tensor operators a closed expression is obtained for the most general case of angular correlation. The structure of the correlation function is explained by means of semiclassical considerations.

  6. Energy correlation functions for jet substructure

    E-print Network

    Salam, Gavin P.

    We show how generalized energy correlation functions can be used as a powerful probe of jet substructure. These correlation functions are based on the energies and pair-wise angles of particles within a jet, with (N?+?1)-point ...

  7. Percolation of secret correlations in a network

    E-print Network

    Raul, Garcia-Patron

    In this work, we explore the analogy between entanglement and secret classical correlations in the context of large networks—more precisely, the question of percolation of secret correlations in a network. It is known that ...

  8. Correlation, hierarchies, and networks in financial markets

    E-print Network

    Tumminello, M; Mantegna, R N

    2008-01-01

    We discuss some methods to quantitatively investigate the properties of correlation matrices. Correlation matrices play an important role in portfolio optimization and in several other quantitative descriptions of asset price dynamics in financial markets. Specifically, we discuss how to define and obtain hierarchical trees, correlation based trees and networks from a correlation matrix. The hierarchical clustering and other procedures performed on the correlation matrix to detect statistically reliable aspects of the correlation matrix are seen as filtering procedures of the correlation matrix. We also discuss a method to associate a hierarchically nested factor model to a hierarchical tree obtained from a correlation matrix. The information retained in filtering procedures and its stability with respect to statistical fluctuations is quantified by using the Kullback-Leibler distance.

  9. Use of correlation matrices in lattice QCD

    E-print Network

    Lepzelter, David, 1981-

    2004-01-01

    This thesis explores the use of correlation matrices in analyzing Monte Carlo calculations from lattice quantum chromodynamics. Correlation matrices are a powerful tool for examining many problems in which significant ...

  10. Network coded gossip with correlated data

    E-print Network

    Haeupler, Bernhard

    We design and analyze gossip algorithms for networks with correlated data. In these networks, either the data to be distributed, the data already available at the nodes, or both, are correlated. Although coding schemes for ...

  11. Lensless matched spatial filter correlator experiments

    NASA Technical Reports Server (NTRS)

    Shen, M.; Casasent, D.; Luu, T. K.; Feng, B.

    1980-01-01

    By combining a matched spatial filter and holographic optical element on a single plate, a compact optical frequency plane correlator results. Experimental pattern recognition correlation data and a theoretical analysis with experimental verification of the system's shift invariance are provided.

  12. Software correlators as testbeds for RFI algorithms

    E-print Network

    Deller, Adam T

    2010-01-01

    In-correlator techniques offer the possibility of identifying and/or excising radio frequency interference (RFI) from interferometric observations at much higher time and/or frequency resolution than is generally possible with the final visibility dataset. Due to the considerable computational requirements of the correlation procedure, cross-correlators have most commonly been implemented using high-speed digital signal processing boards, which typically require long development times and are difficult to alter once complete. "Software" correlators, on the other hand, make use of commodity server machines and a correlation algorithm coded in a high-level language. They are inherently much more flexible and can be developed - and modified - much more rapidly than purpose-built "hardware" correlators. Software correlators are thus a natural choice for testing new RFI detection and mitigation techniques for interferometers. The ease with which software correlators can be adapted to test RFI detection algorithms ...

  13. Extreme Correlation of International Equity Markets

    Microsoft Academic Search

    François Longin; Bruno Solnik

    2001-01-01

    Testing the hypothesis that international equity market correlation increases in volatile times is a difficult exercise and misleading results have often been reported in the past because of a spurious relationship between correlation and volatility. Using \\

  14. An 18 million year record of vegetation and climate change in northwestern Canada and Alaska: Tectonic and global climatic correlates

    USGS Publications Warehouse

    White, J.M.; Ager, T.A.; Adam, D.P.; Leopold, E.B.; Liu, Gaisheng; Jette, H.; Schweger, C.E.

    1997-01-01

    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.

  15. Correlations in cosmic density fields

    NASA Technical Reports Server (NTRS)

    Bromley, B. C.

    1994-01-01

    A method is proposed to place constraints on the functional form of the high-order correlation functions zeta(sub n) that arise in cosmic density fields at large scales. This technique is based on a mass-in-cell statistic and a difference of mass in partitions of a cell. The relationship between these measures is sensitive to the formal structure of the zeta(sub n) as well as their amplitudes. This relationship is quantified in several theoretical models of structure, based on the hierarchical clustering paradigm. The results lead to a test for specific types of hierarchical clustering that is sensitive to correlations of all orders. The method is applied to examples of simulated large-scaled structure dominated by cold dark matter. In the preliminary study, the hierarchical paradigm appears to be a realistic approximation over a broad range of the scales. Furthermore, there is evidence that graphs of low-order vertices are dominant. On the basis of simulated data a phenomological model is specified that gives a good representation of clustering from linear scales to the strongly clustered regime (zeta(sub 2) approximately 500).

  16. PREFACE: Correlation Dynamics in Nuclei

    NASA Astrophysics Data System (ADS)

    Suzuki, Toshio; Otsuka, Takaharu; Ichimura, Munetake

    2005-01-01

    The International Symposium on `Correlation Dynamics in Nuclei' was held at the Sanjo Kaikan, the University of Tokyo, from the 31 January to 4 February 2005. This symposium was organized on the occasion of the 50th anniversary of the Configuration Mixing theory of Arima and Horie. The symposium was hosted by the University of Tokyo, and supported by the Inoue Foundation for Science, the Japan Atomic Energy Research Institute and the Ministry of Education, Culture, Sports, Science and Technology. The purpose of the symposium was to discuss theoretical and experimental developments and future prospects in physics of correlation dynamics in nuclei, including topics such as effective interactions, shell model studies of configuration mixing and spin-isospin modes in nuclei. It was shown in many ways and angles that the Arima-Horie theory has been a starting point of a variety of developments of the studies in these fields over many decades. The developments have been enhanced by the expansion of computational capabilities and the progress in accelerators, detectors and radioactive beam facilities. We enjoyed 28 excellent and lively invited talks and 30 oral presentations in the symposium with about 90 participants. A special session was dedicated to celebrate the 80th birthday of Professor Igal Talmi, who made invaluable and pioneering works in the shell model theory. Finally, we would like to thank all the speakers and the participants as well as the other organizers for their contributions which made the symposium very successful.

  17. Boeing Shaped Scan Correlator (BOSSCO)

    NASA Astrophysics Data System (ADS)

    Slack, Leonard L.; Witsmeer, A. James

    1980-12-01

    The optical area correlation system developed by The Boeing Company for missile terminal guidance is called BOSSCO. This development was partially funded under the Air Force Armament Laboratories (AFATL), Eglin AFB, Florida, which sponsored the Pavestorm III program as a highly accurate clear-weather weapon for stationary targets. This paper describes the system design, hardware design and test program conducted during the period of the contract (1972-1974). Also described is the redesign and retest effort conducted under independent research funding to correct design errors and reach the present performance level. Alternate applications including navigation update, map matching and image correlation or alignment were later explored both independently and under contract with the Engineering Topographical Laboratories (ETL), Fort Belvoir, Virginia. Further flight testing and laboratory demonstrations took place over Fort Belvoir and at the Army Missile Command (MICOM), Huntsville, Alabama. This system represents a unique capability which, when mechanized in large scale integrated circuit technology, could significantly increase our national defense capability by providing a near-term fire-and-forget guidance option.

  18. DISCO: distance and spectrum correlation optimization alignment for two-dimensional gas chromatography time-of-flight mass spectrometry-based metabolomics.

    PubMed

    Wang, Bing; Fang, Aiqin; Heim, John; Bogdanov, Bogdan; Pugh, Scott; Libardoni, Mark; Zhang, Xiang

    2010-06-15

    A novel peak alignment algorithm using a distance and spectrum correlation optimization (DISCO) method has been developed for two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC/TOF-MS)-based metabolomics. This algorithm uses the output of the instrument control software, ChromaTOF, as its input data. It detects and merges multiple peak entries of the same metabolite into one peak entry in each input peak list. After a z-score transformation of metabolite retention times, DISCO selects landmark peaks from all samples based on both two-dimensional retention times and mass spectrum similarity of fragment ions measured by Pearson's correlation coefficient. A local linear fitting method is employed in the original two-dimensional retention time space to correct retention time shifts. A progressive retention time map searching method is used to align metabolite peaks in all samples together based on optimization of the Euclidean distance and mass spectrum similarity. The effectiveness of the DISCO algorithm is demonstrated using data sets acquired under different experiment conditions and a spiked-in experiment. PMID:20476746

  19. Three-point correlations of galaxy clusters

    NASA Technical Reports Server (NTRS)

    Toth, Gabor; Hollosi, Joseph; Szalay, Alexander S.

    1989-01-01

    A relation between two- and three-point correlation functions similar to that of galaxies is presently established by estimating the irreducible angular three-point correlation function of Abell clusters in distance classes 5 and 6, for Galactic latitudes below 40 deg. The shape of the three-point correlation function is fully consistent with the quadratic scaling law found by Groth and Peebles (1977) for galaxies. The three-point correlation function is inconsistent with the expectations from biasing.

  20. Survey of current correlators and applications

    NASA Technical Reports Server (NTRS)

    Lahmeyer, C. R.; Brokl, S. S.

    1987-01-01

    With this summary an attempt is made to contact as many users as possible so as to provide summary data on correlation systems, both in use and as planned. Data on currently available very large scale integration (VLSI) chips and complete systems are included. Also, several planned correlator systems are described and summarized in tabular form. Finally, a description is given of the work being done in the Communications Systems Research Section on VLSI correlator chips and complete correlator systems.

  1. Bessel function output from an optical correlator.

    PubMed

    Davis, J A; Haavig, L L; Cottrell, D M

    1997-04-10

    We introduce a new filter for an optical correlator that produces a Bessel function correlation output. The advantage of this type of output is that the width of the central dark spot at the center of the correlator output is narrower than the width of the usual correlation spot. In addition, the dark spot is insensitive to changes in illumination intensity. We present experimental results with which we write the new filter onto a programmable magneto-optic spatial light modulator. PMID:18253215

  2. Inclination to speeding and its correlates among two-wheeler riding Indian youth

    PubMed Central

    Michael, Rajeev J.; Sharma, Manoj K.; Mehrotra, Seema; Banu, Humera; Kumar, Rajesh; Sudhir, Paulomi M.; Chakrabarthy, Neelima

    2014-01-01

    Context: Concerns about road safety have been increasingly associated with two-wheeler riding and especially with young commuters in India. Aims: The study was designed to explore inclination to speeding and to profile the driving behaviors in two-wheeler riding young men and women who reported a tendency to ride faster than their peers. Design: A cross-sectional survey design was used. Materials and Methods: On the basis of three focus group discussions and review of literature, a survey was prepared to tap domains such as affect states associated with riding/speeding, factors contributing to speeding, inclination for competing, perceived speed and safety, etc. The study sample comprised of 961 two-wheeler riding college-going young men and women in Bangalore. Statistical Analysis: Descriptive and inferential statistical procedures were used including Chi-square, Spearman's rank correlation, and independent sample t-test. Results: The sample was divided into two subgroups on the basis of self-report of greater speeding than one's peers. A subgroup of 349 participants endorsed the item regarding inclination to ride faster than one's peers, whereas, the remaining 612 participants did not endorse it. The profiles of these two subgroups were obtained in terms of sociodemographic variables, riding behaviors, and associated domains. Significant differences between the subgroups emerged on domains such as motives for riding fast, tendency for competing, perceived safety and frequency of minor accidents while riding. Conclusions: Several correlates of the tendency to speeding among young two-wheeler riders emerged that have implications for enhancing safe riding. PMID:25788799

  3. 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

  4. Scale evolution of double parton correlations

    E-print Network

    Tomas Kasemets

    2014-11-17

    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.

  5. Structural relaxation by digital-correlation spectroscopy

    Microsoft Academic Search

    C. Demoulin; C. J. Montrose; N. Ostrowsky

    1974-01-01

    The utility of digital-correlation spectroscopy for investigating structural relaxation in liquids on time scales from 1 musec to 1 sec is established. A digital correlator was used to analyze the Rayleigh scattering of light from undercooled glycerol. The correlation function obtained is related to the isothermal structural relaxation dynamics of the liquid. The data were found to join smoothly with

  6. Technology Brief Fiducial Marker for Correlating Images

    E-print Network

    Technology Brief Fiducial Marker for Correlating Images For further information, contact Dorene Price Description: A fiducial marker that effectively correlates images of x-ray fluorescence in the analysis, the grid has two layers whereas one layer is useful for correlating an analytical image

  7. Functional Multiple-Set Canonical Correlation Analysis

    ERIC Educational Resources Information Center

    Hwang, Heungsun; Jung, Kwanghee; Takane, Yoshio; Woodward, Todd S.

    2012-01-01

    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…

  8. Correlation estimates Saudi crude oil viscosity

    Microsoft Academic Search

    M. Al-Blehed; M. H. Sayyouth; S. M. Desouky

    1990-01-01

    A new correlation estimates the viscosity of Saudi crude oils in the undersaturated oil regions as a function of pressure, temperature, and API-gravity. Field data of 182 crude oil samples obtained from the major producing areas of Saudi reservoirs were statistically treated and used to derive the viscosity correlation. The accuracy of the developed correlation was determined using statistical error

  9. Statistical correlations of crime with arrests

    NASA Astrophysics Data System (ADS)

    Kuelling, Albert C.

    1997-01-01

    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.

  10. Economic and Educational Correlates of TIMSS Results

    ERIC Educational Resources Information Center

    Mikk, Jaan

    2005-01-01

    The good knowledge of the correlates of educational achievement highlights the ways to the efficient use of economic and human capital in raising the efficiency of education. The present paper investigates the correlates and compares the values of the correlates for the Republic of Lithuania with the average international values. The data for the…

  11. Are Quantum Correlations Genuinely Quantum?

    NASA Astrophysics Data System (ADS)

    di Lorenzo, Antonio

    2012-05-01

    It is shown that the probabilities for the spin singlet can be reproduced through classical resources, with no communication between the distant parties, by using merely shared (pseudo-)randomness. If the parties are conscious beings aware of both the hidden-variables and the random mechanism, then one has a conspiracy. If the parties are aware of only the random variables, they may be induced to believe that they are able to send instantaneous information to one another. It is also possible to reproduce the correlations at the price of reducing the detection efficiency. It is further demonstrated that the same probability decomposition could be realized through action-at-a-distance, provided it existed.

  12. Are Quantum Correlations Genuinely Quantum?

    NASA Astrophysics Data System (ADS)

    di Lorenzo, Antonio

    2013-01-01

    It is shown that the probabilities for the spin singlet can be reproduced through classical resources, with no communication between the distant parties, by using merely shared (pseudo-)randomness. If the parties are conscious beings aware of both the hidden-variables and the random mechanism, then one has a conspiracy. If the parties are aware of only the random variables, they may be induced to believe that they are able to send instantaneous information to one another. It is also possible to reproduce the correlations at the price of reducing the detection efficiency. It is further demonstrated that the same probability decomposition could be realized through action-at-a-distance, provided it existed.

  13. Vibration analysis using digital correlation

    NASA Technical Reports Server (NTRS)

    Gilbert, John A.; Lehner, David L.; Dudderar, T. Dixon; Matthys, Donald R.

    1988-01-01

    This paper demonstrates the use of a computer-based optical method for locating the positions of nodes and antinodes in vibrating members. Structured light patterns are projected at an angle onto the vibrating surface using a 35 mm slide projector. The vibrating surface and the projected images are captured in a time averaged photograph which is subsequently digitized. The inherent fringe patterns are filtered to determine amplitudes of vibration, and computer programs are used to compare the time averaged images to images recorded prior to excitation to locate nodes and antinodes. Some of the influences of pattern regularity on digital correlation are demonstrated, and a speckle-based method for determining the mode shapes and the amplitudes of vibration with variable sensitivity is suggested.

  14. Fully resolved NMR correlation spectroscopy.

    PubMed

    Pitoux, Daisy; Plainchont, Bertrand; Merlet, Denis; Hu, Zhaoyu; Bonnaffé, David; Farjon, Jonathan; Giraud, Nicolas

    2015-06-15

    A new correlation experiment cited as "push-G-SERF" is reported. In the resulting phased 2D spectrum, the chemical shift information is selected along the direct dimension, whereas scalar couplings involving a selected proton nucleus are edited in the indirect domain. The robustness of this pulse sequence is demonstrated on compounds with increasing structural and spectral complexity, using state-of-the-art spectrometers. It allows for full resolution of both dimensions of the spectrum, yielding a straightforward assignment and measurement of the coupling network around a given proton in the molecule. This experiment is intended for chemists who want to address efficiently the structural analysis of molecules with an overcrowded spectrum. PMID:25941095

  15. Correlative microscopy of detergent granules.

    PubMed

    van Dalen, G; Nootenboom, P; Heussen, P C M

    2011-03-01

    The microstructure of detergent products for textile cleaning determines to a large extent the physical properties of these products. Correlative microscopy was used to reveal the microstructure by reconciling images obtained by scanning electron microscopy with energy dispersive X-ray analysis, X-ray microtomography and Fourier transform infrared microscopy. These techniques were applied on the same location of a subsample of a spray-dried detergent base powder embedded in polyacrylate. In this way, the three-dimensional internal and external structure of detergent granules could be investigated from milli to nano scale with detailed spatial information about the components present. This will generate knowledge how to design optimal microstructures for laundry products to obtain product properties demanded by the market. This method is also very useful for other powder systems used in a large variety of industries (e.g. for pharmaceutical, food, ceramic and metal industries). PMID:21118223

  16. [Neurobiological correlates of EMDR therapy].

    PubMed

    Pagani, Marco; Lorenzo, Giorgio di; Verardo, Annarita; Nicolais, Giampaolo; Monaco, Leonardo; Niolu, Cinzia; Fernandez, Isabel; Siracusano, Alberto

    2012-01-01

    The EEGs in a group of ten subjects with major psychological trauma treated with EMDR and in ten controls have been registered both during the listening of the autobiographical narrative of the index trauma (script) and during a whole EMDR session. The EEGs have been performed again during the last EMDR session when patients were free of symptoms. During script listening a prevalent activation of the limbic regions corresponding to prefrontal and orbitofrontal cortex has been registered, being explained as the emotional arousal during trauma reliving at the symptomatic phase. The significant decrease of such activations during the late asymptomatic phase represents the neurobiological correlate of recovery. Moreover, the evidence of significant cortical activation in the parietal-temporo-occipital areas, during the last session, suggests a switch of the dominant electrical signal towards cortical areas with a prevalent cognitive function. PMID:22622274

  17. Correlation Functions in Stochastic Inflation

    E-print Network

    Vennin, Vincent

    2015-01-01

    Combining the stochastic and $\\delta N$ formalisms, we derive non perturbative analytical expressions for all correlation functions of scalar perturbations in single-field, slow-roll inflation. The standard, classical formulas are recovered as saddle-point limits of the full results. This yields a classicality criterion that shows that stochastic effects are small only if the potential is sub-Planckian and not too flat. The saddle-point approximation also provides an expansion scheme for calculating stochastic corrections to observable quantities perturbatively in this regime. In the opposite regime, we show that a strong suppression in the power spectrum is generically obtained, and comment on the physical implications of this effect.

  18. Observed Correlations in Minkowski Space

    E-print Network

    Richard A. Mould

    2003-07-22

    The author has proposed five rules that permit conscious observers to be included in quantum mechanics. In the present paper, these rules are applied to the observation of a non-local pair of correlated particles. Rule (4) again prevents an anomalous result. Two different kinds of relativistic state reduction are considered, where these differ in the way that they impose boundary conditions in Minkowski space. In response to a problem that arises in this context, we require the Lorentz invariance of stochastic hits. And finally, it is claimed that the rules proposed by the author are themselves relativistically covariant with some qualification. Key Words: brain states, boundary conditions, consciousness, decoherence, macroscopic superposition, probability current, von Neumann, wave collapse.

  19. Correlation effects on topological insulator

    E-print Network

    Xiong-Jun Liu; Yang Liu; Xin Liu

    2010-11-24

    The strong correlation effects on topological insulator are studied in a two-sublattice system with an onsite single-particle energy difference $\\Delta$ between two sublattices. At $\\Delta=0$, increasing the onsite interaction strength $U$ drives the transition from the quantum spin Hall insulating state to the non-topological antiferromagnetic Mott-insulating (AFMI) state. When $\\Delta$ is larger than a certain value, a topologically trivial band insulator or AFMI at small values of $U$ may change into a quantum anomalous Hall state with antiferromagnetic ordering at intermediate values of $U$. Further increasing $U$ drives the system back into the topologically trivial state of AFMI. The corresponding phenomena is observable in the solid state and cold atom systems. We also propose a scheme to realize and detect these effects in cold atom systems.

  20. Electric polarization in correlated insulators

    NASA Astrophysics Data System (ADS)

    Nourafkan, R.; Kotliar, G.

    2013-10-01

    We derive a formula for the electric polarization of interacting insulators, expressed in terms of the full Green's and vertex functions. We exemplify this method in the half-filled ionic Hubbard model treated within dynamical mean field theory (DMFT). The electric polarization of a correlated band insulator is determined by the interplay of ionicity and covalency, and both quantities are renormalized by the electron-electron interactions. We introduce quasiparticle approximations to the exact equation for the polarization, and compare the results of these approximations with those of the exact DMFT formulation and of static mean field theories such as the LDA+U. The latter overestimates the electronic contribution to the electric polarization when the quasiparticle weight of the active bands is very small.

  1. Physiological correlates of mental workload

    NASA Technical Reports Server (NTRS)

    Zacharias, G. L.

    1980-01-01

    A literature review was conducted to assess the basis of and techniques for physiological assessment of mental workload. The study findings reviewed had shortcomings involving one or more of the following basic problems: (1) physiologic arousal can be easily driven by nonworkload factors, confounding any proposed metric; (2) the profound absence of underlying physiologic models has promulgated a multiplicity of seemingly arbitrary signal processing techniques; (3) the unspecified multidimensional nature of physiological "state" has given rise to a broad spectrum of competing noncommensurate metrics; and (4) the lack of an adequate definition of workload compels physiologic correlations to suffer either from the vagueness of implicit workload measures or from the variance of explicit subjective assessments. Using specific studies as examples, two basic signal processing/data reduction techniques in current use, time and ensemble averaging are discussed.

  2. Investigation of correlation classification techniques

    NASA Technical Reports Server (NTRS)

    Haskell, R. E.

    1975-01-01

    A two-step classification algorithm for processing multispectral scanner data was developed and tested. The first step is a single pass clustering algorithm that assigns each pixel, based on its spectral signature, to a particular cluster. The output of that step is a cluster tape in which a single integer is associated with each pixel. The cluster tape is used as the input to the second step, where ground truth information is used to classify each cluster using an iterative method of potentials. Once the clusters have been assigned to classes the cluster tape is read pixel-by-pixel and an output tape is produced in which each pixel is assigned to its proper class. In addition to the digital classification programs, a method of using correlation clustering to process multispectral scanner data in real time by means of an interactive color video display is also described.

  3. Hyper-Rayleigh scattering from correlated molecules

    NASA Astrophysics Data System (ADS)

    Shelton, David P.

    2013-04-01

    The polarization dependence of hyper-Rayleigh scattering has been calculated for spherical domains of orientation correlated molecules. Distributions with radial or azimuthal mean polar orientation of the molecules are found that give results consistent with experimental observations, and expressions for the polarization ratios in terms of the product of correlation strength and correlated domain size are derived for these distributions. Assuming a plausible correlation strength, it is estimated that the correlated domain size in typical polar liquids is of order 100 molecular diameters.

  4. Behavior of Quantum Correlations under Local Noise

    E-print Network

    Alexander Streltsov; Hermann Kampermann; Dagmar Bruß

    2011-06-10

    We characterize the behavior of quantum correlations under the influence of local noisy channels. Intuition suggests that such noise should be detrimental for quantumness. When considering qubit systems, we show for which channel this is indeed the case: the amount of quantum correlations can only decrease under the action of unital channels. However, non-unital channels (e.g. such as dissipation) can create quantum correlations for some initially classical state. Furthermore, for higher-dimensional systems even unital channels may increase the amount of quantum correlations. Thus, counterintuitively, local decoherence can generate quantum correlations.

  5. EARLINET correlative measurements for CALIPSO

    NASA Astrophysics Data System (ADS)

    Mattis, Ina; Mona, Lucia; Müller, Detlef; Pappalardo, Gelsomina; Alados-Arboledas, Lucas; D'Amico, Giuseppe; Amodeo, Aldo; Apituley, Arnoud; Baldasano, José Maria; Böckmann, Christine; Bösenberg, Jens; Chaikovsky, Anatoli; Comeron, Adolfo; Giannakaki, Elina; Grigorov, Ivan; Guerrero Rascado, Juan Luis; Gustafsson, Ove; Iarlori, Marco; Linne, Holger; Mitev, Valentin; Molero Menendez, Francisco; Nicolae, Doina; Papayannis, Alexandros; Garcia-Pando, Carlos Perez; Perrone, Maria Rita; Pietruczuk, Aleksander; Putaud, Jean-Philippe; Ravetta, Francois; Rodríguez, Alejandro; Seifert, Patric; Sicard, Michaël; Simeonov, Valentin; Sobolewski, Piotr; Spinelli, Nicola; Stebel, Kerstin; Stohl, Andreas; Tesche, Matthias; Trickl, Thomas; Wang, Xuan; Wiegner, Matthias

    2007-10-01

    The European Aerosol Research Lidar Network (EARLINET) was established in 2000 to derive a comprehensive, quantitative, and statistically significant data base for the aerosol distribution on the European scale. At present, EARLINET consists of 25 stations: 16 Raman lidar stations, including 8 multi-wavelength Raman lidar stations which are used to retrieve aerosol microphysical properties. EARLINET performs a rigorous quality assurance program for instruments and evaluation algorithms. All stations measure simultaneously on a predefined schedule at three dates per week to obtain unbiased data for climatological studies. Since June 2006 the first backscatter lidar is operational aboard the CALIPSO satellite. EARLINET represents an excellent tool to validate CALIPSO lidar data on a continental scale. Aerosol extinction and lidar ratio measurements provided by the network will be particularly important for that validation. The measurement strategy of EARLINET is as follows: Measurements are performed at all stations within 80 km from the overpasses and additionally at the lidar station which is closest to the actually overpassed site. If a multi-wavelength Raman lidar station is overpassed then also the next closest 3+2 station performs a measurement. Altogether we performed more than 1000 correlative observations for CALIPSO between June 2006 and June 2007. Direct intercomparisons between CALIPSO profiles and attenuated backscatter profiles obtained by EARLINET lidars look very promising. Two measurement examples are used to discuss the potential of multi-wavelength Raman lidar observations for the validation and optimization of the CALIOP Scene Classification Algorithm. Correlative observations with multi-wavelength Raman lidars provide also the data base for a harmonization of the CALIPSO aerosol data and the data collected in future ESA lidar-in-space missions.

  6. Correlated randomness and switching phenomena

    NASA Astrophysics Data System (ADS)

    Stanley, H. E.; Buldyrev, S. V.; Franzese, G.; Havlin, S.; Mallamace, F.; Kumar, P.; Plerou, V.; Preis, T.

    2010-08-01

    One challenge of biology, medicine, and economics is that the systems treated by these serious scientific disciplines have no perfect metronome in time and no perfect spatial architecture-crystalline or otherwise. Nonetheless, as if by magic, out of nothing but randomness one finds remarkably fine-tuned processes in time and remarkably fine-tuned structures in space. Further, many of these processes and structures have the remarkable feature of “switching” from one behavior to another as if by magic. The past century has, philosophically, been concerned with placing aside the human tendency to see the universe as a fine-tuned machine. Here we will address the challenge of uncovering how, through randomness (albeit, as we shall see, strongly correlated randomness), one can arrive at some of the many spatial and temporal patterns in biology, medicine, and economics and even begin to characterize the switching phenomena that enables a system to pass from one state to another. Inspired by principles developed by A. Nihat Berker and scores of other statistical physicists in recent years, we discuss some applications of correlated randomness to understand switching phenomena in various fields. Specifically, we present evidence from experiments and from computer simulations supporting the hypothesis that water’s anomalies are related to a switching point (which is not unlike the “tipping point” immortalized by Malcolm Gladwell), and that the bubbles in economic phenomena that occur on all scales are not “outliers” (another Gladwell immortalization). Though more speculative, we support the idea of disease as arising from some kind of yet-to-be-understood complex switching phenomenon, by discussing data on selected examples, including heart disease and Alzheimer disease.

  7. Histopathologic Composition of Cerebral Thrombi of Acute Stroke Patients Is Correlated with Stroke Subtype and Thrombus Attenuation

    PubMed Central

    Niesten, Joris M.; van der Schaaf, Irene C.; van Dam, Lievay; Vink, Aryan; Vos, Jan Albert; Schonewille, Wouter J.; de Bruin, Peter C.; Mali, Willem P. T. M.; Velthuis, Birgitta K.

    2014-01-01

    Introduction We related composition of cerebral thrombi to stroke subtype and attenuation on non-contrast CT (NCCT) to gain more insight in etiopathogenesis and to validate thrombus attenuation as a new imaging biomarker for acute stroke. Methods We histopathologically investigated 22 thrombi retrieved after mechanical thrombectomy in acute stroke patients. First, thrombi were classified as fresh, lytic or organized. Second, percentages of red blood cells (RBCs), platelets and fibrin and number of red, white (respectively RBCs or platelets outnumbering other components with ?15%) or mixed thrombi were compared between large artery atherosclerosis (LAA), cardioembolism, dissection and unknown subtype. Third, correlation between attenuation and RBCs, platelets and fibrin was calculated using Pearson's correlation coefficients (r). Results Thrombi were fresh in 73% (n?=?16), lytic in 18% (n?=?4) and organized in 9% (n?=?2). The stroke cause was LAA in eight (36%), cardioembolism in six (27%), dissection in three (14%), and unknown in five (23%) patients. LAA thrombi showed the highest percentage RBCs (median 50 (range 35–90)), followed by dissection (35 (20–40), p?=?0.05), cardioembolism (35 (5–45), p?=?0.013) and unknown subtype (25 (2–40), p?=?0.006). No differences in platelets (p?=?0.16) and fibrin (p?=?0.52) between subtypes were found. LAA thrombi were classified as red or mixed (both n?=?4), cardioembolisms as mixed (n?=?5) or white (n?=?1) and dissection as mixed (n?=?3). There was a moderate positive correlation between attenuation and RBCs (r?=?0.401, p?=?0.049), and weak negative correlations with platelets (r?=??0.368, p?=?0.09) and fibrin (r?=??0.073, p?=?0.75). Conclusions The majority of cerebral thrombi is fresh. There are no differences in age of thrombi between subtypes. LAA thrombi have highest percentages RBCs, cardioembolism and unknown subtype lowest. No relationship exists between subtype and platelets or fibrin percentages. We found a correlation between the RBC-component and thrombus attenuation, which improves validation of thrombus attenuation on NCCT as an imaging biomarker for stroke management. PMID:24523944

  8. Correlates of physical activity and the theory of planned behavior between African American women who are physically active and those who are not.

    PubMed

    Carter-Parker, Kathleen; Edwards, Karethy A; McCleary-Jones, Voncella

    2012-01-01

    Many people have positive intention to engage in physical activity but fail to act. In general, Physical activity (PA) levels among Americans are declining. However, when compared to all other racial groups, middle aged African American women (AAW) have the lowest rate of PA participation. The lack of physical activity has dire illness consequences for AAW Despite significant efforts to increase physical activity to levels that benefit health, the need to understand successful translation of intention to engage in physical activity, attitude, subjective norm, and perceived behavioral control is warranted in order to design theoretically derived culturally tailored interventions to increase physical activity participation among middle aged AAW. Moreover, there is a paucity of studies that use theoretical underpinnings to elucidate the differences between middle aged AAW who are physically active and those who are not physically active. Therefore, the Theory of Planned Behavior's (TPB) measuring the constructs of intention, subjective norm, attitude, and perceived behavioral control was used to guide the design of this study. One-hundred-fifty-three respondents completed the socio-demographic profile, a Theory of Planned Behavior Questionnaire (TPBQ), and the International Physical Activity Questionnaire (IPAQ). The Pearson's Product-Moment Correlation Coefficient indicated the highest correlation between intention and attitude r (137) = .740, p < .001. The correlation between intention and perceived behavior control was r (137) = .546, p < .001; intention and physical activity r (137) = .439, p < .001; attitude and perceived behavior control r (137) = .487, p < .001; and attitude and physical activity r (137) = .429, p < .001 demonstrated a moderately strong positive relationship. Subjective norm and perceived behavior control demonstrate the smallest correlational significance r (137) = .264, p <.001. Multiple regression analysis revealed attitude towards physical activity, and perceived behavior control for physical activity were statistically and clinically significant predictors of physical activity among the middle-aged African American women in this study. PMID:22924229

  9. Correlated Variability in Laminar Cortical Circuits

    PubMed Central

    Hansen, Bryan J.; Chelaru, Mircea I.; Dragoi, Valentin

    2012-01-01

    SUMMARY Despite the fact that strong trial-to-trial correlated variability in responses has been reported in many cortical areas, recent evidence suggests that neuronal correlations are much lower than previously thought. Here, we used multicontact laminar probes to revisit the issue of correlated variability in primary visual (V1) cortical circuits. We found that correlations between neurons depend strongly on local network context—whereas neurons in the input (granular) layers showed virtually no correlated variability, neurons in the output layers (supragranular and infragranular) exhibited strong correlations. The laminar dependence of noise correlations is consistent with recurrent models in which neurons in the granular layer receive intracortical inputs from nearby cells, whereas supragranular and infragranular layer neurons receive inputs over larger distances. Contrary to expectation that the output cortical layers encode stimulus information most accurately, we found that the input network offers superior discrimination performance compared to the output networks. PMID:23141070

  10. Correlates of depression in bipolar disorder.

    PubMed

    Moore, Paul J; Little, Max A; McSharry, Patrick E; Goodwin, Guy M; Geddes, John R

    2014-02-01

    We analyse time series from 100 patients with bipolar disorder for correlates of depression symptoms. As the sampling interval is non-uniform, we quantify the extent of missing and irregular data using new measures of compliance and continuity. We find that uniformity of response is negatively correlated with the standard deviation of sleep ratings (? = -0.26, p = 0.01). To investigate the correlation structure of the time series themselves, we apply the Edelson-Krolik method for correlation estimation. We examine the correlation between depression symptoms for a subset of patients and find that self-reported measures of sleep and appetite/weight show a lower average correlation than other symptoms. Using surrogate time series as a reference dataset, we find no evidence that depression is correlated between patients, though we note a possible loss of information from sparse sampling. PMID:24352942

  11. Correlations between major brain regions in Chiroptera.

    PubMed

    Pirlot, P; Jolicoeur, P

    1982-01-01

    Unlike small homogeneous nuclei, progression indices of large heterogeneous brain regions show no negative correlations and give no evidence of compensatory effects, presumably because the evolutionary progressions and regressions of multiple neighboring functions mask each other. The diencephalon and various parts of the telencephalon show large positive correlations, apparently reflecting the general increase in size of the brain, relatively to body weight, from presumably primitive to advanced forms. The neocortex is strongly correlated with the striatum, a putative precursor, and with the diencephalon, but less strongly correlated with the cerebellum in Chiroptera than in Primates. The mesencephalon is moderately correlated with the medulla oblongata and cerebellum, but uncorrelated with all parts of the telencephalon except the paleocortex. The bulbus olfactorius is correlated with the septum, schizocortex and hippocampus, but these correlations may be due mostly to the progression of these four structures in Megachiroptera and their regression in insectivorous Microchiroptera, and may not imply major direct functional relationships. PMID:12050841

  12. Sensitivity of adjustment to parameter correlations and to response-parameter correlations

    SciTech Connect

    Wagschal, J.J. [Racah Inst. of Physics, Hebrew Univ. of Jerusalem, Edmond J. Safra Campus, Jerusalem, 91904 (Israel)

    2011-07-01

    The adjusted parameters and response, and their respective posterior uncertainties and correlations, are presented explicitly as functions of all relevant prior correlations for the two parameters, one response case. The dependence of these adjusted entities on the various prior correlations is analyzed and portrayed graphically for various valid correlation combinations on a simple criticality problem. (authors)

  13. Monogamy of Correlations vs. Monogamy of Entanglement

    E-print Network

    Michael Seevinck

    2010-01-19

    A fruitful way of studying physical theories is via the question whether the possible physical states and different kinds of correlations in each theory can be shared to different parties. Over the past few years it has become clear that both quantum entanglement and non-locality (i.e., correlations that violate Bell-type inequalities) have limited shareability properties and can sometimes even be monogamous. We give a self-contained review of these results as well as present new results on the shareability of different kinds of correlations, including local, quantum and no-signalling correlations. This includes an alternative simpler proof of the Toner-Verstraete monogamy inequality for quantum correlations, as well as a strengthening thereof. Further, the relationship between sharing non-local quantum correlations and sharing mixed entangled states is investigated, and already for the simplest case of bi-partite correlations and qubits this is shown to be non-trivial. Also, a recently proposed new interpretation of Bell's theorem by Schumacher in terms of shareability of correlations is critically assessed. Finally, the relevance of monogamy of non-local correlations for secure quantum key distribution is pointed out, although, and importantly, it is stressed that not all non-local correlations are monogamous.

  14. Oscillatory correlates of autobiographical memory.

    PubMed

    Knyazev, Gennady G; Savostyanov, Alexander N; Bocharov, Andrey V; Dorosheva, Elena A; Tamozhnikov, Sergey S; Saprigyn, Alexander E

    2015-03-01

    Recollection of events from one's own life is referred to as autobiographical memory. Autobiographical memory is an important part of our self. Neuroimaging findings link self-referential processes with the default mode network (DMN). Much evidence coming primarily from functional magnetic resonance imaging studies shows that autobiographical memory and DMN have a common neural base. In this study, electroencephalographic data collected in 47 participants during recollection of autobiographical episodes were analyzed using temporal and spatial independent component analyses in combination with source localization. Autobiographical remembering was associated with an increase of spectral power in alpha and beta and a decrease in delta band. The increase of alpha power, as estimated by sLORETA, was most prominent in the posterior DMN, but was also observed in visual and motor cortices, prompting an assumption that it is associated with activation of DMN and inhibition of irrelevant sensory and motor areas. In line with data linking delta oscillations with aversive states, decrease of delta power was more pronounced in episodes associated with positive emotions, whereas episodes associated with negative emotions were accompanied by an increase of delta power. Vividness of recollection correlated positively with theta oscillations. These results highlight the leading role of alpha oscillations and the DMN in the processes accompanying autobiographical remembering. PMID:25523347

  15. de Finetti reductions for correlations

    NASA Astrophysics Data System (ADS)

    Arnon-Friedman, Rotem; Renner, Renato

    2015-05-01

    When analysing quantum information processing protocols, one has to deal with large entangled systems, each consisting of many subsystems. To make this analysis feasible, it is often necessary to identify some additional structures. de Finetti theorems provide such a structure for the case where certain symmetries hold. More precisely, they relate states that are invariant under permutations of subsystems to states in which the subsystems are independent of each other. This relation plays an important role in various areas, e.g., in quantum cryptography or state tomography, where permutation invariant systems are ubiquitous. The known de Finetti theorems usually refer to the internal quantum state of a system and depend on its dimension. Here, we prove a different de Finetti theorem where systems are modelled in terms of their statistics under measurements. This is necessary for a large class of applications widely considered today, such as device independent protocols, where the underlying systems and the dimensions are unknown and the entire analysis is based on the observed correlations.

  16. Quantum correlations which imply causation

    E-print Network

    Joseph Fitzsimons; Jonathan Jones; Vlatko Vedral

    2013-02-12

    In ordinary, non-relativistic, quantum physics, time enters only as a parameter and not as an observable: a state of a physical system is specified at a given time and then evolved according to the prescribed dynamics. While the state can, and usually does, extend across all space, it is only defined at one instant of time, in conflict with special relativity where space and time are treated on an equal footing. Here we ask what would happen if we defined the notion of the quantum density matrix for multiple spatial and temporal measurements. We introduce the concept of a pseudo-density matrix which treats space and time indiscriminately. This matrix in general fails to be positive for timelike separated measurements, motivating us to define a measure of causality that discriminates between spacelike and timelike correlations. Important properties of this measure, such as monotonicity under local operations, are proved. Two qubit NMR experiments are presented that illustrate how a temporal pseudo-density matrix approaches a genuinely allowed density matrix as the amount of decoherence is increased between two consecutive measurements.

  17. Correlations in the Monte Carlo Glauber model

    NASA Astrophysics Data System (ADS)

    Blaizot, Jean-Paul; Broniowski, Wojciech; Ollitrault, Jean-Yves

    2014-09-01

    Event-by-event fluctuations of observables are often modeled using the Monte Carlo Glauber model, in which the energy is initially deposited in sources associated with wounded nucleons. In this paper, we analyze in detail the correlations between these sources in proton-nucleus and nucleus-nucleus collisions. There are correlations arising from nucleon-nucleon correlations within each nucleus, and correlations due to the collision mechanism, which we dub twin correlations. We investigate this new phenomenon in detail. At the Brookhaven Relativistic Heavy Ion Collider and CERN Large Hadron Collider energies, correlations are found to have modest effects on size and eccentricity fluctuations, such that the Glauber model produces to a good approximation a collection of independent sources.

  18. Correlation estimates Saudi crude oil viscosity

    SciTech Connect

    Al-Blehed, M.; Sayyouth, M.H.; Desouky, S.M. (King Saud Univ., Riyadh (SA))

    1990-03-05

    A new correlation estimates the viscosity of Saudi crude oils in the undersaturated oil regions as a function of pressure, temperature, and API-gravity. Field data of 182 crude oil samples obtained from the major producing areas of Saudi reservoirs were statistically treated and used to derive the viscosity correlation. The accuracy of the developed correlation was determined using statistical error analysis. Statistical error analysis techniques were employed to check the validity of the developed correlation as compared to other published crude oil viscosity correlations using the field data of Saudi reservoirs. The results show that the developed correlation provides a more accurate estimation of crude oil viscosity with an average relative error of {minus} 13.58%.

  19. Dynamic joint transform correlator of images

    NASA Astrophysics Data System (ADS)

    Angervaks, A. E.; Malyi, A. F.; Fedorov, I. U.; Shcheulin, A. S.

    2008-03-01

    In this article principles of operation of a coherent optical image correlator based on a well know optical joint transform correlator are examined. Theoretical predictions and experimental data for of the optical image correlator with a holographic filter recorded on a thin holographic photographic plates PFG - 01 are analyzed. Results of the operation of the dynamic joint transform correlator on the basis of cadmium fluoride crystal, CdF2, with bistable impurity centers are demonstrated. Calculated and experimental correlation peak intensity dependencies with the scale and angular mismatch between an observed and reference objects for static and dynamic joint transform correlators are compared. Tangram figures were used as a test images. In the paper all computations were performed by use of MATLAB 7.0.1 mathematical program.

  20. Angular correlations and high energy evolution

    SciTech Connect

    Kovner, Alex [Physics Department, University of Connecticut, 2152 Hillside Road, Storrs, Connecticut 06269-3046 (United States); Lublinsky, Michael [Physics Department, Ben-Gurion University of the Negev, Beer Sheva 84105 (Israel); Physics Department, University of Connecticut, 2152 Hillside Road, Storrs, Connecticut 06269-3046 (United States)

    2011-11-01

    We address the question of to what extent JIMWLK evolution is capable of taking into account angular correlations in a high energy hadronic wave function. Our conclusion is that angular (and indeed other) correlations in the wave function cannot be reliably calculated without taking into account Pomeron loops in the evolution. As an example we study numerically the energy evolution of angular correlations between dipole scattering amplitudes in the framework of the large N{sub c} approximation to JIMWLK evolution (the 'projectile dipole model'). Target correlations are introduced via averaging over an (isotropic) ensemble of anisotropic initial conditions. We find that correlations disappear very quickly with rapidity even inside the saturation radius. This is in accordance with our physical picture of JIMWLK evolution. The actual correlations inside the saturation radius in the target QCD wave function, on the other hand, should remain sizable at any rapidity.

  1. Correlation of the Apparent Diffusion Coefficient (ADC) with the Standardized Uptake Value (SUV) in Lymph Node Metastases of Non-Small Cell Lung Cancer (NSCLC) Patients Using Hybrid 18F-FDG PET/MRI

    PubMed Central

    Schaarschmidt, Benedikt Michael; Buchbender, Christian; Nensa, Felix; Grueneien, Johannes; Gomez, Benedikt; Köhler, Jens; Reis, Henning; Ruhlmann, Verena; Umutlu, Lale; Heusch, Philipp

    2015-01-01

    Objective To compare the apparent diffusion coefficient (ADC) in lymph node metastases of non-small cell lung cancer (NSCLC) patients with standardized uptake values (SUV) derived from combined 18F-fluoro-deoxy-glucose-positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI). Material and Methods 38 patients with histopathologically proven NSCLC (mean age 60.1 ± 9.5y) received whole-body PET/CT (Siemens mCT™) 60min after injection of a mean dose of 280 ± 50 MBq 18F-FDG and subsequent PET/MRI (mean time after tracer injection: 139 ± 26 min, Siemens Biograph mMR). During PET acquisition, simultaneous diffusion-weighted imaging (DWI, b values: 0, 500, 1000 s/mm²) was performed. A maximum of 10 lymph nodes per patient suspicious for malignancy were analyzed. Regions of interest (ROI) were drawn covering the entire lymph node on the attenuation-corrected PET-image and the monoexponential ADC-map. According to histopathology or radiological follow-up, lymph nodes were classified as benign or malignant. Pearson’s correlation coefficients were calculated for all lymph node metastases correlating SUVmax and SUVmean with ADCmean. Results A total of 146 suspicious lymph nodes were found in 25 patients. One hundred lymph nodes were eligible for final analysis. Ninety-one lymph nodes were classified as malignant and 9 as benign according to the reference standard. In malignant lesions, mean SUVmax was 9.1 ± 3.8 and mean SUVmean was 6.0 ± 2.5 while mean ADCmean was 877.0 ± 128.6 x10-5 mm²/s in PET/MRI. For all malignant lymph nodes, a weak, inverse correlation between SUVmax and ADCmean as well as SUVmean and ADCmean (r = -0.30, p<0.05 and r = -0.36, p<0.05) existed. Conclusion The present data show a weak inverse correlation between increased glucose-metabolism and cellularity in lymph node metastases of NSCLC patients. 18F-FDG-PET and DWI thus may offer complementary information for the evaluation of treatment response in lymph node metastases of NSCLC. PMID:25574968

  2. Are galaxies more strongly correlated than clusters?

    NASA Technical Reports Server (NTRS)

    Szalay, A. S.; Aschramm, D. N.

    1985-01-01

    Distributions of galaxies and of clusters of galaxies have been investigated using the correlation function, the excess probability over random that there are two objects separated by a distance r. It is shown here that if the amplitudes of the cluster-cluster correlation function are made dimensionless, systematic changes with cluster richness vanish, implying scale invariance in the cluster process. The dimensionless galaxy-galaxy correlation seems stronger, implying gravitational enhancement on smaller scales.

  3. Detrended cross-correlation analysis of electroencephalogram

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Zhao, Da-Qing

    2012-02-01

    In the paper we use detrended cross-correlation analysis (DCCA) to study the electroencephalograms of healthy young subjects and healthy old subjects. It is found that the cross-correlation between different leads of a healthy young subject is larger than that of a healthy old subject. It was shown that the cross-correlation relationship decreases with the aging process and the phenomenon can help to diagnose whether the subject's brain function is healthy or not.

  4. Link Envelope Correlation in the Backscatter Channel

    Microsoft Academic Search

    Joshua D. Griffin; Gregory D. Durgin

    2007-01-01

    High-frequency backscatter radio systems operate in the dyadic backscatter channel, a pinhole channel whose envelope probability density function and bit-error-rate performance are strongly affected by link envelope correlation - the envelope correlation between the forward and backscatter links of the dyadic backscatter channel. This paper shows that link envelope correlation is most detrimental for backscatter radio systems using co-located reader

  5. The Bonn MK IV Correlator Project

    NASA Astrophysics Data System (ADS)

    Alef, W.; Graham, D. A.; Zensus, J. A.; Müskens, A.; Schlüter, W.

    2000-05-01

    We describe the present status of the VLBI correlator in Bonn. The old MK III correlator has been made Y2K compliant, but it is expected to be taken out of operation this year. We report our first experience with the new MK IV correlator, jointly operated by the MPIfR and the BKG, as well as our short-term and long-term plans, both with respect to astronomical and geodetic requirements.

  6. Fast Correlation Attacks on Certain Stream Ciphers

    Microsoft Academic Search

    Willi Meier; Othmar Staffelbach

    1989-01-01

    Suppose that the output of a running key generator employed in a stream cipher is correlated to a linear feedback shift register sequence (LFSR sequence) a with correlation probabilityp>0.5. Then two new correlation attacks (Algorithms A and B) are presented to determine the initial digits of a, provided that the numbert of feedback taps is small (tp?0.75). The computational complexity

  7. Robust canonical correlations: A comparative study

    Microsoft Academic Search

    J. A. Branco; Christophe Croux; P. Filzmoser; M. R. Oliveira

    2005-01-01

    Summary  Several approaches for robust canonical correlation analysis will be presented and discussed. A first method is based on the\\u000a definition of canonical correlation analysis as looking for linear combinations of two sets of variables having maximal (robust)\\u000a correlation. A second method is based on alternating robust regressions. These methods are discussed in detail and compared\\u000a with the more traditional approach

  8. Correlates of Employee Lateness: Some Theoretical Considerations

    Microsoft Academic Search

    Meni Koslowsky; Abraham Sagie; Moshe Krausz; Ahuva Dolman Singer

    1997-01-01

    Using hypothesis-driven meta-analytic procedures on 30 samples containing 118 correlations, researchers examined competing models of the relationship between lateness and assorted work-related variables. Consistent with a progression withdrawal model, the mean corrected lateness–absence correlation, .40, was found to be higher than the lateness–turnover correlation, .27. Hypotheses regarding the relationships between lateness and attitudes, performance, and demographics were generally supported. Methodological

  9. Plane correlations in small colliding systems

    NASA Astrophysics Data System (ADS)

    Yan, Li

    2015-06-01

    I propose event-plane correlations as a test of collectivity in small colliding systems: In d -Au and 3He-Au collisions, I predict a strong anticorrelation between elliptic and triangular flow, generated by the geometry of the light projectile. A significant anticorrelation is also predicted in central p -Pb collisions at the CERN Large Hadron Collider, which is solely generated by fluctuations. Similar, but stronger correlation patterns are predicted in correlations involving dipolar flow.

  10. Local correlation measures and atomic shell structure

    NASA Astrophysics Data System (ADS)

    Sagar, Robin P.; Guevara, Nicolais L.

    2007-04-01

    The correlation coefficient and mutual information, used to measure the interdependence between two variables, are generalized to the local level and employed to examine the radial distribution of electron correlation. We compare the behavior of the two local measures with regard to their emphasis on core and valence correlation and show that while there are differences, both are able to correctly reproduce the shell structure in atomic systems.

  11. Statistical correlation between atomic electron pairs

    NASA Astrophysics Data System (ADS)

    Sagar, Robin P.; Laguna, Humberto G.; Guevara, Nicolais L.

    2011-10-01

    The statistical correlation between a pair of electrons in Hartree-Fock orbitals is measured by mutual information and studied in position and in momentum space. We show that there are same- and opposite-spin orbital pairs where the correlation is larger in momentum space. Among these are opposite-spin valence shell pairs where the correlation arises from the indistinguishability of electron spins.

  12. Correlation of Helium Solubility in Liquid Nitrogen

    NASA Technical Reports Server (NTRS)

    VanDresar, Neil T.; Zimmerli, Gregory A.

    2012-01-01

    A correlation has been developed for the equilibrium mole fraction of soluble gaseous helium in liquid nitrogen as a function of temperature and pressure. Experimental solubility data was compiled and provided by National Institute of Standards and Technology (NIST). Data from six sources was used to develop a correlation within the range of 0.5 to 9.9 MPa and 72.0 to 119.6 K. The relative standard deviation of the correlation is 6.9 percent.

  13. Parton and Hadron Correlations in Jets

    E-print Network

    Rudolph C. Hwa; Zhiguang Tan

    2005-05-31

    Correlation between shower partons is first studied in high $p_T$ jets. Then in the framework of parton recombination the correlation between pions in heavy-ion collisions is investigated. Since thermal partons play very different roles in central and peripheral collisions, it is found that the correlation functions of the produced hadrons behave very differently at different centralities, especially at intermediate $p_T$. The correlation function that can best exhibit the distinctive features is suggested. There is not a great deal of overlap between what we can calculate and what has been measured. Nevertheless, some aspects of our results compare favorably with experimental data.

  14. Long-range orientation correlation in water

    NASA Astrophysics Data System (ADS)

    Shelton, David P.

    2014-12-01

    Strong short-range intermolecular interactions result in position and orientation correlations between nearest neighbour molecules in isotropic liquids, but it is generally assumed that such correlations extend at most a few molecular diameters. Results from second-harmonic light scattering experiments presented here reveal long-range molecular orientation correlations in liquid water, where the molecular dipole orientation distribution has the form of a nearly pure transverse vector field. Spatial scales in the range 200-2000 nm are probed by the angle-dependent measurements and the observed correlations are thought to result from rotation-translation coupling in acoustic phonons in the liquid.

  15. Correlation measurements with on-off detectors

    NASA Astrophysics Data System (ADS)

    Sperling, J.; Vogel, W.; Agarwal, G. S.

    2013-10-01

    We present a general method to detect nonclassical radiation fields with systems of on-off detectors. We especially study higher order correlations for the identification of nonclassical radiation. This allows us to directly characterize quantum correlations by the statistics measured with systems of on-off detectors. Additionally, we generalize our method to multiple detector systems for measurements of correlations between light fields. We also consider multimode radiation fields and isolate nonclassicality in terms of the space time correlations. Finally, we present results for the quantum statistics using on-off detectors operating in nonlinear detection modes.

  16. Particle Correlations in Z and WW Events

    E-print Network

    T. Kress

    2002-05-10

    Important information about the dynamics of hadron production can be obtained by the study of particle correlations. More than 16 million hadronic Z0 decays and several thousand W+W- events have been recorded from the four LEP collaborations between 1989 and 2000. Recently, in Z0 decays, new results of Bose-Einstein correlations in pairs of pions and Fermi-Dirac correlations for antiproton pairs were reported. In fully-hadronic W+W- decays particle correlations were used to study whether the two W bosons decay independently.

  17. Parallel auto-correlative statistics with VTK.

    SciTech Connect

    Pebay, Philippe Pierre [Kitware, France; Bennett, Janine Camille

    2013-08-01

    This report summarizes existing statistical engines in VTK and presents both the serial and parallel auto-correlative statistics engines. It is a sequel to [PT08, BPRT09b, PT09, BPT09, PT10] which studied the parallel descriptive, correlative, multi-correlative, principal component analysis, contingency, k-means, and order statistics engines. The ease of use of the new parallel auto-correlative statistics engine is illustrated by the means of C++ code snippets and algorithm verification is provided. This report justifies the design of the statistics engines with parallel scalability in mind, and provides scalability and speed-up analysis results for the autocorrelative statistics engine.

  18. Graphical correlation of gaging-station records

    USGS Publications Warehouse

    Searcy, James K.

    1960-01-01

    A gaging-station record is a sample of the rate of flow of a stream at a given site. This sample can be used to estimate the magnitude and distribution of future flows if the record is long enough to be representative of the long-term flow of the stream. The reliability of a short-term record for estimating future flow characteristics can be improved through correlation with a long-term record. Correlation can be either numerical or graphical, but graphical correlation of gaging-station records has several advantages. The graphical correlation method is described in a step-by-step procedure with an illustrative problem of simple correlation, illustrative problems of three examples of multiple correlation--removing seasonal effect--and two examples of correlation of one record with two other records. Except in the problem on removal of seasonal effect, the same group of stations is used in the illustrative problems. The purpose of the problems is to illustrate the method--not to show the improvement that can result from multiple correlation as compared with simple correlation. Hydrologic factors determine whether a usable relation exists between gaging-station records. Statistics is only a tool for evaluating and using an existing relation, and the investigator must be guided by a knowledge of hydrology.

  19. RECONSTRUCTING THE SHAPE OF THE CORRELATION FUNCTION

    SciTech Connect

    Huffenberger, K. M.; Galeazzi, M.; Ursino, E. [Department of Physics, University of Miami, Coral Gables, FL 33146 (United States)

    2013-06-01

    We develop an estimator for the correlation function which, in the ensemble average, returns the shape of the correlation function, even for signals that have significant correlations on the scale of the survey region. Our estimator is general and works in any number of dimensions. We develop versions of the estimator for both diffuse and discrete signals. As an application, we apply them to Monte Carlo simulations of X-ray background measurements. These include a realistic, spatially inhomogeneous population of spurious detector events. We discuss applying the estimator to the averaging of correlation functions evaluated on several small fields, and to other cosmological applications.

  20. Correlation time for step structural fluctuations

    NASA Astrophysics Data System (ADS)

    Bondarchuk, O.; Dougherty, D. B.; Degawa, M.; Williams, E. D.; Constantin, M.; Dasgupta, C.; Das Sarma, S.

    2005-01-01

    Time-dependent scanning tunneling microscopy has been used to evaluate step fluctuations as a function of temperature (300-450K) on Ag(111) films grown on mica. The temporal correlation function scales as a power law in time t1/n with measured values of 1/n varying over a range of 0.19±0.04 to 0.29±0.04 with no correlation on temperature. The average value of 1/n=0.24±0.01 is consistent with step-edge diffusion limited fluctuations ( n=z=4 , conserved noise). The magnitude of the time correlation function and the width of the fluctuations both scale with temperature with the same apparent activation energy of Eeff=0.21±0.02eV , indicating that the correlation time is at most weakly temperature dependent. Direct analysis of the autocorrelation function confirms that the correlation time is at most weakly temperature dependent, and thus the apparent correlation length is strongly temperature dependent. This behavior can be reproduced by assuming that the apparent correlation length is governed by the longest wavelength of step fluctuations that can be sampled in the measurement time interval. Evaluation of the correlation time for previous measurements for Al/Si(111) (z=2) yields the same conclusion about measurement time interval. In both cases the ratio of the measurement time to the effective correlation time is on the order of 10.

  1. Software correlators as testbeds for RFI algorithms

    NASA Astrophysics Data System (ADS)

    Deller, A.

    2010-05-01

    In-correlator techniques offer the possibility of identifying and/or excising radio frequency interference (RFI) from interferometric observations at much higher time and/or frequency resolution than is generally possible with the final visibility dataset. Due to the considerable computational requirements of the correlation procedure, cross-correlators have most commonly been implemented using high-speed digital signal processing boards, which typically require long development times and are difficult to alter once complete. "Software" correlators, on the other hand, make use of commodity server machines and a correlation algorithm coded in a high-level language. They are inherently much more flexible and can be developed - and modified - much more rapidly than purpose-built "hardware" correlators. Software correlators are thus a natural choice for testing new RFI detection and mitigation techniques for interferometers. The ease with which software correlators can be adapted to test RFI detection algorithms is demonstrated by the addition of kurtosis detection and plotting to the widely used DiFX software correlator, which highlights previously unknown short -duration RFI at the Hancock VLBA station.

  2. The Correlation between Polybrominated Diphenyl Ethers (PBDEs) and Thyroid Hormones in the General Population: A Meta-Analysis

    PubMed Central

    Zhao, Xuemin; Wang, Hailong; Li, Jing; Shan, Zhongyan; Teng, Weiping; Teng, Xiaochun

    2015-01-01

    Objective Certain epidemiological studies have suggested exposure to polybrominated diphenyl ethers (PBDEs) affect the production and secretion of thyroid hormones (TH); however, conflicting results have been reported in different studies. There is not a convincing conclusion about this debate to date. Materials and Methods To perform a meta-analysis determining if there are correlations between PBDEs exposure and the serum levels of TH. Medical and scientific literature databases were searched for articles that met the eligibility criteria. The included articles were assessed for methodological quality. The correlation coefficient values or regression coefficient values between PBDEs and thyroid stimulating hormone (TSH) or total thyroxine (TT4) from each article were used for analysis. Data Synthesis Sixteen articles were included in this meta-analysis. Pearson correlation coefficients (r) were directly collected or calculated from data given in the articles. Then, Fisher’s z transformation was performed to convert each correlation coefficient to an approximately normal distribution. For z values between PBDEs exposure and TSH levels, the pooled z value for 18 studies was 0.08 (95% CI: -0.06, 0.22), and indicated significant heterogeneity (I2 values = 90.7%). Subgroup analysis was performed based on the median values of serum PBDEs in each study, there was not significant heterogeneity in each of the four subgroups (I2 values <30%). In meta-analysis of z values between PBDEs exposure and the levels of TT4, the pooled z value for 11 studies was -0.02 (95% CI: -0.11, 0.08), and also indicated significant heterogeneity (I2 values = 57.6%). Similar subgroup analysis was done for the PBDEs exposures and the levels of TT4. No significant heterogeneity was shown in either of the two subgroups (I2 values = 0). Conclusion The findings in our meta-analysis indicate the effects of PBDEs on thyroid function may mainly depend on PBDEs exposure and their levels found in serum. The relationship between PBDEs exposure and changes in thyroid function seem to fit an approximate u-shaped curve. These predictions await further verification, namely a prospective longitudinal study. PMID:25992849

  3. Demographic and clinical factors correlating with high levels of psychological distress in HIV-positive women living in Ontario, Canada.

    PubMed

    Benoit, Anita C; Light, Lucia; Burchell, Ann N; Gardner, Sandra; Rourke, Sean B; Wobeser, Wendy; Loutfy, Mona R

    2014-01-01

    The concept of psychological distress includes a range of emotional states with symptoms of depression and anxiety and has yet to be reported in HIV-positive women living in Ontario, Canada, who are known to live with contributing factors. This study aimed to determine the prevalence, severity, and correlates of psychological distress among women accessing HIV care participating in the Ontario HIV Treatment Network Cohort Study using the Kessler Psychological Distress Scale (K10). The K10 is a 10-item, five-level response scale. K10 values range from 10 to 50 with values less than or equal to 19 categorized as not clinically significant, scores between 20 and 24 as moderate levels, 25-29 as high, and 30-50 as very high psychological distress. Correlates of psychological distress were assessed using the Pearson's chi-square test and univariate and multivariate logistic regression analysis. Moderate, high, and very high levels of psychological distress were experienced by 16.9, 10.4, and 15.1% of the 337 women in our cohort, respectively, with 57.6% reporting none. Psychological distress levels greater than 19, correlated with being unemployed (vs. employed/student/retired; AOR = 0.33, 95% CI: 0.13-0.83), living in a household without their child/children (AOR = 2.45, 95% CI: 1.33-4.52), CD4 counts < 200 cells/mm(3) (AOR = 2.07, 95% CI: 0.89-4.80), and to a lesser degree an education of some college or less (vs. completed college or higher; AOR=1.71, 95% CI: 0.99-2.95). Age and ethnicity, a priori variables of interest, did not correlate with psychological distress. Findings suggest that socioeconomic factors which shape the demography of women living with HIV in Ontario, low CD4 counts, and losing the opportunity to care for their child/children has a significant relationship with psychological distress. Approaches to manage psychological distress should address and make considerations for the lived experiences of women since they can act as potential barriers to improving psychological well-being. PMID:24215281

  4. Immunoprobe Localization by Correlative Microscopy

    NASA Astrophysics Data System (ADS)

    Calarco, Patricia G.

    2000-05-01

    : Mammalian oocytes present challenges for optimal study by electron microscopy (EM) due to their high level of hydration, their large size, and their relatively undifferentiated cytoplasm. This is particularly true for immunoprobe localization which has led to a dependence on light microscopic (LM) techniques, such as immunofluorescence. This study presents correlative LM and EM data to describe an example of the failure of light microscopy to correctly predict the ultrastructure of one particular organelle. Immunoprobe localization of centrosome and microtubule organizing center (MTOC) antigens in the mammalian egg was made by immunofluorescence and post-embedding immuno-EM, with best EM results achieved in Lowicryl-embedded material. Centrosome and MTOC antigens were detected by 5051 and an antibody to gamma tubulin ([gamma]-tubulin). Gamma tubulin is a highly conserved element of MTOCs in many species and, thus, is highly diagnostic for them; it is also considered essential for microtubule (MT) nucleation. Results indicate that prior to nuclear breakdown, 5051 antigens and [gamma]-tubulin are found exclusively in a type of ``organelle,'' the multivesicular aggregate (MVA), that bears no resemblance to MTOCs at the ultrastructural level. Until recently, the MVA was considered an organelle without a known function, while standard MTOCs were presumed to be the entities that carry the proteins recognized by centrosome antibodies. LM localization of centrosomal antigens carried the presumption that standard MTOCs were the entities labeled. Whether or not other molecules are shown to co-localize to these MVA, the presence of [gamma]-tubulin supports the contention that MVA, or their contents, serve as centrosomal precursors with a unique ultrastructure. Thus, dependence on LM techniques alone can lead to erroneous conclusions on organelle identity and function.

  5. Electrophysiological correlates of Complement Coercion

    PubMed Central

    Kuperberg, Gina R.; Choi, Arim; Cohn, Neil; Paczynski, Martin; Jackendoff, Ray

    2011-01-01

    This study examined the electrophysiological correlates of complement coercion. Event-related potentials (ERPs) were measured as participants read and made acceptability judgments about plausible coerced sentences, plausible non-coerced sentences, and highly implausible animacy violated sentences (“The journalist began/wrote/astonished the article before his coffee break”). Relative to non-coerced complement nouns, the coerced nouns evoked an N400 effect. This effect was not modulated by the number of possible activities implied by the coerced nouns (e.g. began reading the article; began writing the article), and did not differ in either magnitude or scalp distribution from the N400 effect evoked by the animacy violated complement nouns. We suggest that the N400 modulation to both coerced and the animacy violated complement nouns reflected different types of mismatches between the semantic restrictions of the verb and the semantic properties of the incoming complement noun. This is consistent with models holding that a verb’s semantic argument structure is represented and stored at a distinct level from its syntactic argument structure. Unlike the coerced complement noun, the animacy violated nouns also evoked a robust P600 effect, which may have been triggered by the judgments of the highly implausible (syntactically-determined) meanings of the animacy violated propositions. No additional ERP effects were seen in the coerced sentences until the sentence-final word which, relative to sentence-final words in the non-coerced sentences, evoked a sustained anteriorly-distributed positivity. We suggest that this effect reflected delayed attempts to retrieve the specific event(s) implied by coerced complement nouns. PMID:19702471

  6. Revisiting Melton: Analyzing the correlation structure of geomorphological and climatological parameters

    NASA Astrophysics Data System (ADS)

    Carothers, R. A.; Sangireddy, H.; Passalacqua, P.

    2013-12-01

    In his expansive 1957 study of over 80 basins in Arizona, Colorado, New Mexico, and Utah, Mark Melton measured key morphometric, soil, land cover, and climatic parameters [Melton, 1957]. He identified correlations between morphological parameters and climatic regimes in an attempt to characterize the geomorphology of the basin as a function of climate and vegetation. Using modern techniques such as high resolution digital terrain models in combination with high spatial resolution weather station records, vector soil maps, seamless raster geological data, and land cover vector maps, we revisit Melton's 1957 dataset with the following hypotheses: (1) Patterns of channelization carry strong, codependent signatures in the form of statistical correlations of rainfall variability, soil type, and vegetation patterns. (2) Channelization patterns reflect the erosion processes on sub-catchment scale and the subsequent processes of vegetation recovery and gullying. In order to characterize various topographic and climatic parameters, we obtain elevation and land cover data from the USGS National Elevation dataset, climate data from the Western Regional Climate Center and PRISM climate group database, and soil type from the USDA STATSGO soil database. We generate a correlative high resolution database on vegetation, soil cover, lithology, and climatology for the basins identified by Melton in his 1957 study. Using the GeoNet framework developed by Passalacqua et al. [2010], we extract various morphological parameters such as slope, drainage density, and stream frequency. We also calculate metrics for patterns of channelization such as number of channelized pixels in a basin and channel head density. In order to understand the correlation structure between climate and morphological variables, we compute the Pearson's correlation coefficient similar to Melton's analysis and also explore other statistical procedures to characterize the feedbacks between these variables. By identifying the differences in Melton's and our results, we address the influence of climate over the degree of channel dissection in the landscape. References: Melton, M. A. (1957). An analysis of the relations among elements of climate, surface properties, and geomorphology (No. CU-TR-11). COLUMBIA UNIV NEW YORK Passalacqua, P., Do Trung, T., Foufoula-Georgiou, E., Sapiro, G., & Dietrich, W. E. (2010). A geometric framework for channel network extraction from lidar: Nonlinear diffusion and geodesic paths. Journal of Geophysical Research: Earth Surface (2003-2012), 115(F1). PRISM Climate Group, Oregon State University, http://prism.oregonstate.edu, created 4 Feb 2004 Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. U.S. General Soil Map (STATSGO2). Available online at http://soildatamart.nrcs.usda.gov USGS National Map Viewer, United States Geological Survey. Web. 10 June 2013. http://viewer.nationalmap.gov/viewer/ Western U.S. Historical Climate Summaries, Western Regional Climate Group, 2013. Web. 10 June 2013. http://www.wrcc.dri.edu/Climsum.html

  7. Correlation between Systemic Oxidative Stress and Intraocular Pressure Level

    PubMed Central

    Tanito, Masaki; Kaidzu, Sachiko; Takai, Yasuyuki; Ohira, Akihiro

    2015-01-01

    Background The involvement of local and systemic oxidative stress in intraocular pressure (IOP) elevation and optic nerve damage has been hypothesized in the pathogenesis of glaucoma. We reported previously that the level of systemic antioxidative capacity is lower in patients with open-angle glaucoma than controls without glaucoma. Here, we assessed the correlation between IOP and systemic levels of prooxidants and antioxidants by analyzing the blood biochemistry in patients with glaucoma. Methods Peripheral blood samples were collected from Japanese patients with primary open-angle glaucoma (n = 206), exfoliation syndrome (n = 199), and controls (n = 126). Serum levels of lipid peroxides, ferric-reducing activity, and thiol antioxidant activity were measured by diacron reactive oxygen metabolite (dROM), biological antioxidant potential (BAP), and sulfhydryl (SH) tests, respectively, using a free radical analyzer. To test the possible effect of oxidative stress on IOP levels, the patients were classified into one of four groups (Q1, Q2, Q3, and Q4, with Q1 having the lowest IOP) based on the quartile value of IOP. For this classification, the known highest IOP value in both the right and left eyes was regarded as each subject’s IOP. For comparisons among the IOP groups, the differences were calculated using one-way analysis of variance followed by post-hoc unpaired t-tests. To adjust for differences in demographic characteristic distributions, the dROM, BAP, and SH test values were compared among the IOP groups using multiple logistic regression analysis; the odds ratio (OR) of each variable was calculated with the Q1 group as the reference. Results The dROM and the SH levels did not differ significantly (p = 0.6704 and p = 0.6376, respectively) among the four IOP groups. The BAP levels differed significantly (p = 0.0115) among the four IOP groups; the value was significantly lower in the Q4 group (1,932 ?mol/L) compared with the Q1 (2,023 ?mol/L, p = 0.0042) and Q2 (2,003 ?mol/L, p = 0.0302) groups and significantly lower in the Q3 group (1,948 ?mol/L) than the Q1 (p = 0.0174) group. After adjustment for differences in various demographic characteristics, lower BAP values were significantly associated with the classification into higher IOP groups (Q3 group, p = 0.0261 and OR = 0.06/range; Q4 group, p = 0.0018 and OR = 0.04/range). The dROM and SH values did not reach significance in any comparisons. Conclusions Lower systemic antioxidant capacity measured by ferric-reducing activity is involved in the pathogenesis of open-angle glaucoma via its roles in IOP elevation. PMID:26186651

  8. Correlation effects in multiple hard scattering

    E-print Network

    Markus Diehl

    2013-06-27

    Correlations between the incoming partons in multiple hard scattering can affect both the event rate and kinematic distributions in the final state. In this talk, I discuss different types of correlations relevant for double parton scattering in proton-proton collisions.

  9. On rank correlation in information retrieval evaluation

    Microsoft Academic Search

    Massimo Melucci

    2007-01-01

    Some methods for rank correlation in evaluation are examined and their relative advantages and disadvantages are discussed. In particular, it is suggested that different test statistics should be used for providing additional information about the experiments other that the one provided by statistical significance testing. Kendall's ? is often used for testing-rank correlation, yet it is little appropriate if the

  10. Lattice Calculation of QCD Vacuum Correlation Functions

    E-print Network

    M. -C. Chu; J. M. Grandy; S. Huang; J. W. Negele

    1992-08-28

    The first exploratory calculations of QCD vacuum correlation functions on a lattice are reported. Qualitative agreement with phenomenological results is obtained in channels for which experimental data are available, and these correlation functions are shown to be useful in exploring approximations based on sum rules and interacting instantons.

  11. Transformation of stimulus correlations by the retina

    NASA Astrophysics Data System (ADS)

    Prentice, Jason; Simmons, Kristina; Tkacik, Gasper; Homann, Jan; Yee, Heather; Palmer, Stephanie; Nelson, Phillip; Balasubramanian, Vijay

    2014-03-01

    Correlations in the responses of sensory neurons seem to waste neural resources, but can carry cues about structured stimuli and help the brain correct for response errors. To assess how the retina negotiates this tradeoff, we measured simultaneous responses from many retinal ganglion cells presented with natural and artificial stimuli that varied in correlation structure. Responding to spatio-temporally structured stimuli such as natural movies, pairs of ganglion cells were more correlated than in response to white noise checkerboards, but were much less correlated than predicted by a non-adapting functional model of retinal response. Meanwhile, responding to stimuli with purely spatial correlations, pairs of ganglion cells showed increased correlations consistent with a static, non-adapting receptive field and nonlinearity. We found that in response to spatio- temporally correlated stimuli, ganglion cells had faster temporal kernels and tended to have stronger surrounds. These properties of individual cells, along with gain changes that opposed changes in effective contrast at the ganglion cell input, largely explained the pattern of correlations across stimuli.

  12. Structural analysis of covariance and correlation matrices

    Microsoft Academic Search

    Karl G. Jöreskog

    1978-01-01

    A general approach to the analysis of covariance structures is considered, in which the variances and covariances or correlations of the observed variables are directly expressed in terms of the parameters of interest. The statistical problems of identification, estimation and testing of such covariance or correlation structures are discussed.Several different types of covariance structures are considered as special cases of

  13. Correlation of capillary number relationships for sandstone

    Microsoft Academic Search

    I. Chatzis; N. R. Morrow

    1981-01-01

    Capillary number relationships are presented for displacement of residual oil, and for displacement of oil which is initially continuous from water-wet sandstone having permeabilities which varied over about two orders of magnitude. It was found that the onset of mobilization could be correlated with sample permeability. Relationships between normalized reduced residual oil saturation and capillary number were correlated satisfactorily for

  14. Quantum correlation with entanglement and mutual entropy

    Microsoft Academic Search

    Takashi Matsuoka

    2011-01-01

    We discuss the correlations on classical and quantum systems from the information theoretical points of view. There exists\\u000a an essential difference between such two types of correlation. How can we understand such difference? This report is a review\\u000a of our recent works on the quantum information theory with entanglement.

  15. Personality Correlates of Pain Perception and Tolerance.

    ERIC Educational Resources Information Center

    Lukin, Penny R.; Ray, A. Bartow

    1982-01-01

    Explored personality correlates of pain perception and tolerance in a nonmedical sample and setting. Results showed no significant correlations with personality measures and cold-pressor scores, but a significant relationship between pain tolerance and cognitive focus; those who focused on the experimental situation had much shorter tolerance…

  16. Correcting Correlations When Predicting Success in College

    ERIC Educational Resources Information Center

    Saupe, Joe L.; Eimers, Mardy T.

    2010-01-01

    The purpose of this study is to illustrate techniques for correcting a correlation between a predictor of success in college (admission test score or indicator of high school performance) with a measure of success in college (one-year retention or first-year GPA) given the restricted variances in the population used to calculate the correlations.…

  17. ANALYZING CORRELATIONS BETWEEN STREAM AND WATERSHED ATTRIBUTES

    EPA Science Inventory

    Bivariate correlation analysis has been widely used to explore relationships between stream and watershed attributes that have all been measured on the same set of watersheds or sampling locations. Researchers routinely test H0: =0 for each correlation in a large table and then ...

  18. Periodically correlated processes and their stationary dilations

    NASA Technical Reports Server (NTRS)

    Miamee, A. G.

    1988-01-01

    An explicit form for a stationary dilation for periodically correlated random processes is obtained. This is then used to give spectral conditions for a periodically correlated process to be non-deterministic, purely deterministic, minimal, and to have a positive angle between its past and future.

  19. Accurate Structural Correlations from Maximum Likelihood Superpositions

    Microsoft Academic Search

    Douglas L. Theobald; Deborah S. Wuttke

    2008-01-01

    The cores of globular proteins are densely packed, resulting in complicated networks of structural interactions. These interactions in turn give rise to dynamic structural correlations over a wide range of time scales. Accurate analysis of these complex correlations is crucial for understanding biomolecular mechanisms and for relating structure to function. Here we report a highly accurate technique for inferring the

  20. Correlation measurements of tokamak edge plasma fluctuations

    SciTech Connect

    Zacek, F.; Kryska, L.; Stoeckel, J. [Institute of Plasma Physics, Prague (Czech Republic)

    1992-02-01

    A three-channel analog correlator for monitoring edge plasma electrostatic fluctuations is described. The correlator was used for measurement of the turbulent radial particle flux in the OH and combined OH/LHCD regimes on the Castor tokamak. 11 refs., 3 figs.

  1. Intermittency and correlations in hadronic Z decays

    Microsoft Academic Search

    K Ackerstaff; Gideon Alexander; J Allison; N Altekamp; K J Anderson; S Anderson; S Arcelli; S Asai; S F Ashby; D A Axen; Georges Azuelos; A H Ball; E Barberio; R J Barlow; J Richard Batley; S Baumann; J Bechtluft; T Behnke; K W Bell; G Bella; A Bellerive; Stanislaus Cornelius Maria Bentvelsen; Siegfried Bethke; S Betts; O Biebel; A Biguzzi; Volker Blobel; Ian J Bloodworth; P Bock; J Böhme; D Bonacorsi; M Boutemeur; S Braibant; P G Bright-Thomas; L Brigliadori; R M Brown; Helfried J Burckhart; P Capiluppi; R K Carnegie; A A Carter; J R Carter; C Y Chang; D G Charlton; D Chrisman; C Ciocca; P E L Clarke; E Clay; I Cohen; J E Conboy; O C Cooke; C Couyoumtzelis; R L Coxe; M Cuffiani; S Dado; G M Dallavalle; R Davis; S De Jong; A de Roeck; P J Dervan; Klaus Desch; B Dienes; M S Dixit; J Dubbert; E Duchovni; G Duckeck; I P Duerdoth; P G Estabrooks; E Etzion; Franco Luigi Fabbri; A Fanfani; M Fanti; A A Faust; F Fiedler; M Fierro; I Fleck; R Folman; A Frey; A Fürtjes; D I Futyan; P Gagnon; J W Gary; J Gascon; S M Gascon-Shotkin; G Gaycken; C Geich-Gimbel; G Giacomelli; P Giacomelli; V Gibson; W R Gibson; D M Gingrich; D A Glenzinski; J Goldberg; W Gorn; C Grandi; K Graham; E Gross; Jacob Grunhaus; M Gruwé; G G Hanson; M Hansroul; M Hapke; K Harder; A Harel; C K Hargrove; M Hauschild; C M Hawkes; R Hawkings; Richard J Hemingway; M Herndon; G Herten; R D Heuer; M D Hildreth; J C Hill; P R Hobson; M Hoch; Andreas Höcker; K Hoffman; R James Homer; A K Honma; D Horváth; K R Hossain; R Howard; P Hüntemeyer; P Igo-Kemenes; D C Imrie; K Ishii; F R Jacob; A Jawahery; H Jeremie; Martin Paul Jimack; C R Jones; P Jovanovic; T R Junk; J I Kanzaki; D A Karlen; V G Kartvelishvili; K Kawagoe; T Kawamoto; P I Kayal; Richard K Keeler; R G Kellogg; B W Kennedy; D H Kim; A Klier; T Kobayashi; M Kobel; T P Kokott; M Kolrep; S Komamiya; R V Kowalewski; T Kress; P Krieger; J Von Krogh; T Kühl; P Kyberd; G D Lafferty; Hagar Yaël Landsman; D Lanske; J Lauber; S R Lautenschlager; I Lawson; J G Layter; D Lazic; A M Lee; Daniel Lellouch; J Letts; L Levinson; R Liebisch; B List; C Littlewood; A W Lloyd; S L Lloyd; F K Loebinger; G D Long; Michael J Losty; J Lü; J Ludwig; D Liu; A Macchiolo; A L MacPherson; W F Mader; M Mannelli; S Marcellini; C Markopoulos; A J Martin; J P Martin; G Martínez; T Mashimo; P Mättig; W J McDonald; J A McKenna; E A McKigney; T J McMahon; R A McPherson; F Meijers; S Menke; F S Merritt; H Mes; J Meyer; Aldo Michelini; S Mihara; G Mikenberg; D J Miller; R Mir; W Mohr; A Montanari; T Mori; K Nagai; I Nakamura; H A Neal; R Nisius; S W O'Neale; F G Oakham; F Odorici; H O Ögren; M J Oreglia; S Orito; J Pálinkás; G Pásztor; J R Pater; G N Patrick; J Patt; R Pérez-Ochoa; S Petzold; P Pfeifenschneider; J E Pilcher; James L Pinfold; D E Plane; P R Poffenberger; B Poli; J Polok; M B Przybycien; C Rembser; Hartmut Rick; S Robertson; S A Robins; N L Rodning; J M Roney; S Rosati; K Roscoe; A M Rossi; Y Rozen; K Runge; O Runólfsson; D R Rust; K Sachs; T Saeki; O Sahr; W M Sang; E Sarkisyan-Grinbaum; C Sbarra; A D Schaile; O Schaile; P Scharff-Hansen; J Schieck; S Schmitt; A Schöning; M Schröder; M Schumacher; C Schwick; W G Scott; R Seuster; T G Shears; B C Shen; C H Shepherd-Themistocleous; P Sherwood; G P Siroli; A Sittler; A Skuja; A M Smith; G A Snow; Randall J Sobie; S Söldner-Rembold; S Spagnolo; M Sproston; A Stahl; K Stephens; J Steuerer; K Stoll; D Strom; R Ströhmer; B Surrow; S D Talbot; P Taras; S Tarem; R Teuscher; M Thiergen; J Thomas; M A Thomson; E Torrence; S Towers; I Trigger; Z L Trócsányi; E Tsur; A S Turcot; M F Turner-Watson; I Ueda; R Van Kooten; P Vannerem; M Verzocchi; H Voss; F Wäckerle; A Wagner; C P Ward; D R Ward; P M Watkins; A T Watson; N K Watson; P S Wells; N Wermes; J S White; G W Wilson; J A Wilson; T R Wyatt; S Yamashita; G Yekutieli; V Zacek; D Zer-Zion

    1999-01-01

    .   A multidimensional study of local multiplicity fluctuations and multiparticle correlations of hadrons produced in Z decays is performed. The study is based on the data sample of more than events recorded with the OPAL detector at LEP. The fluctuations and correlations are analysed in terms of the normalized\\u000a scaled factorial moments and cumulants up to the fifth order. The

  2. Material property correlations for uranium mononitride

    E-print Network

    Hayes, Steven Lowe

    1989-01-01

    linear thermal expansion coefficient), mechanical properties (creep rate, Young's modulus, shear modulus, bulk modulus, Poisson's ratio, and hardness), transport properties (diffusion coefficients, electrical resistivity, and thermal conductivity... Creep Rate Young's Modulus Shear Modulus . Bulk Modulus . . . . . . Poisson's Ratio Hardness. IV TRANSPORT PROPERTY CORRELATIONS Diffusion Coefficient Electrical Resistivity . Thermal Conductivity V THERMODYNAMIC PROPERTY CORRELATIONS...

  3. Modeling discrete modulators for optical correlation

    Microsoft Academic Search

    Jerome Knopp

    1995-01-01

    The practical calculation of optical correlation filters in correlators that use spatial light modulators with discrete elements is based on the assumption that the image on the input modulator can be modeled as a modulated 2D comb function or 'bed of nails'. A 2D discrete Fourier transform (DFT) is used to calculate a filter that is also modeled as a

  4. TV Watcher: Distributed Media Analysis and Correlation

    Microsoft Academic Search

    David Hilley; Ahmed El-Helw; Matthew Wolenetz; Irfan Essa; Phillip Hutto; Thad Starner; Umakishore Ramachandran

    The explosion of available content in broadcast media has cre- ated a desperate need for applications and prerequisite system architectures to support automatic capture, filtration, categoriza- tion, correlation, and higher level inferencing of streaming data from distributed sources. We present TV Watcher, an archetyp- ical example of such an application. TV Watcher performs user- controlled correlation of live television feeds

  5. PCA-Correlated SNPs for Structure Identification

    E-print Network

    Paschou, Peristera

    - correlated SNPs) to reproduce the structure found by PCA on the complete dataset, without use of ancestry information. Evaluating our method on a previously described dataset (10,805 SNPs, 11 populations), we of individuals. Analyzing a Puerto Rican dataset (192 individuals, 7,257 SNPs), we show that PCA-correlated SNPs

  6. Frequency response corrections for eddy correlation systems

    Microsoft Academic Search

    C. J. Moore

    1986-01-01

    Simplified expressions describing the frequency response of eddy correlation systems due to sensor response, path-length averaging, sensor separation and signal processing are presented. A routine procedure for estimating and correcting for the frequency response loss in flux and variance measurements is discussed and illustrated by application to the Institute of Hydrology's ‘Hydra’ eddy correlation system.

  7. Measurements of Energy-Energy-Correlations

    E-print Network

    Erdmann, Martin

    5.1 Definition of Energy-Energy-Correlations . . . . . . . . . . . . . . . . . . . 39 5Measurements of Energy-Energy-Correlations of Ultra-High-Energy Cosmic Rays with the Pierre Auger A RWTH Aachen RWTH Aachen #12;#12;Contents 1 Introduction 1 2 Physics of Ultra-High-Energy Cosmic Rays 3

  8. Life History Patterns and Correlations in Sharks

    Microsoft Academic Search

    Enric Cortés

    2000-01-01

    This study examines life history patterns and correlations between traits related to body size, reproduction, age, and growth in sharks, using data from 230 populations representing 164 species, 19 families, and 7 orders. The analysis focused on interspecific life history variability, but intraspecific and intrapopulation variation were also considered. Interspecifically, body size correlated positively with litter size and offspring size,

  9. Jet-hadron correlations in STAR

    E-print Network

    Alice Ohlson; for the STAR Collaboration

    2011-06-29

    In recent years, the study of dihadron correlations has been one of the primary methods used to investigate the propagation and modification of hard-scattered partons through the QGP. Due to recent advances in jet-finding algorithms, it is now possible to use reconstructed jets in these correlation studies, extending the kinematic reach compared to dihadron analyses. The results of the jet-hadron correlation analysis indicate a broadening and softening of jets that interact with the medium. Jet-hadron correlations can also be used to assess the systematics of other jet-like correlation analyses, such as 2+1 correlations. It is shown that the jets selected in 2+1 correlations are relatively unmodified. Future work will include an analysis of jet-hadron correlations with respect to the event plane to measure the pathlength dependence of parton energy loss. The first steps in this analysis indicate that complications arise when calculating the event plane in the presence of a jet as well as in calculating jet v2. The data analyzed were collected by the STAR detector in sqrt(s_NN) = 200 GeV Au-Au collisions at the Relativistic Heavy Ion Collider (RHIC).

  10. Correction: Strongly correlated plexcitonics: evolution of the Fano resonance in the presence of Kondo correlations.

    PubMed

    Goker, A

    2015-06-01

    Correction for 'Strongly correlated plexcitonics: evolution of the Fano resonance in the presence of Kondo correlations' by A. Goker et al., Phys. Chem. Chem. Phys., 2015, 17, 11569-11576. PMID:25950856

  11. Spectral correlations of fractional Brownian motion

    SciTech Connect

    Oigaard, Tor Arne; Hanssen, Alfred [Department of Physics and Technology, University of Tromsoe, NO-9037 Tromsoe (Norway); Scharf, Louis L. [Department of Electrical and Computer Engineering and Department of Statistics, Colorado State University, Fort Collins, Colorado 80523 (United States)

    2006-09-15

    Fractional Brownian motion (fBm) is a ubiquitous nonstationary model for many physical processes with power-law time-averaged spectra. In this paper, we exploit the nonstationarity to derive the full spectral correlation structure of fBm. Starting from the time-varying correlation function, we derive two different time-frequency spectral correlation functions (the ambiguity function and the Kirkwood-Rihaczek spectrum), and one dual-frequency spectral correlation function. The dual-frequency spectral correlation has a surprisingly simple structure, with spectral support on three discrete lines. The theoretical predictions are verified by spectrum estimates of Monte Carlo simulations and of a time series of earthquakes with a magnitude of 7 and higher.

  12. Correlation function studies for snow and ice

    NASA Technical Reports Server (NTRS)

    Vallese, F.; Kong, J. A.

    1981-01-01

    The random medium model is used to characterize snow and ice fields in the interpretation of active and passive microwave remote sensing data. A correlation function is used to describe the random permittivity fluctuations with the associated mean and variance and correlation lengths; and several samples are investigated to determine typical correlation functions for snow and ice. It is shown that correlation functions are extracted directly from appropriate ground truth data, and an exponential correlation function is observed for snow and ice with lengths corresponding to the actual size of ice particles or air bubbles. Thus, given that a medium has spatially stationary statistics and a small medium, the random medium model can interpret remote sensing data where theoretical parameters correspond to actual physical parameters of the terrain.

  13. Correlated activity supports efficient cortical processing

    PubMed Central

    Hung, Chou P.; Cui, Ding; Chen, Yueh-peng; Lin, Chia-pei; Levine, Matthew R.

    2015-01-01

    Visual recognition is a computational challenge that is thought to occur via efficient coding. An important concept is sparseness, a measure of coding efficiency. The prevailing view is that sparseness supports efficiency by minimizing redundancy and correlations in spiking populations. Yet, we recently reported that “choristers”, neurons that behave more similarly (have correlated stimulus preferences and spontaneous coincident spiking), carry more generalizable object information than uncorrelated neurons (“soloists”) in macaque inferior temporal (IT) cortex. The rarity of choristers (as low as 6% of IT neurons) indicates that they were likely missed in previous studies. Here, we report that correlation strength is distinct from sparseness (choristers are not simply broadly tuned neurons), that choristers are located in non-granular output layers, and that correlated activity predicts human visual search efficiency. These counterintuitive results suggest that a redundant correlational structure supports efficient processing and behavior. PMID:25610392

  14. Quantifying spatial correlations of general quantum dynamics

    NASA Astrophysics Data System (ADS)

    Rivas, Ángel; Müller, Markus

    2015-06-01

    Understanding the role of correlations in quantum systems is both a fundamental challenge as well as of high practical relevance for the control of multi-particle quantum systems. Whereas a lot of research has been devoted to study the various types of correlations that can be present in the states of quantum systems, in this work we introduce a general and rigorous method to quantify the amount of correlations in the dynamics of quantum systems. Using a resource-theoretical approach, we introduce a suitable quantifier and characterize the properties of correlated dynamics. Furthermore, we benchmark our method by applying it to the paradigmatic case of two atoms weakly coupled to the electromagnetic radiation field, and illustrate its potential use to detect and assess spatial noise correlations in quantum computing architectures.

  15. Correlative light and electron microscopy of GFP.

    PubMed

    Grabenbauer, Markus

    2012-01-01

    The correlation of light and electron microscopy (EM) is a powerful tool as it combines the investigation of dynamic processes in vivo with the resolution power of the electron microscope. The green fluorescent proteins (GFPs) and its derivatives revolutionized live-cell light microscopy. Hence, this review outlines correlative microscopy of GFP through photo-oxidation, a method that allows for the direct ultrastructural visualization of fluorophores upon illumination. Oxygen radicals generated during the GFP bleaching process photo-oxidize diaminobenzidine (DAB) into an electron dense precipitate that can be visualized both by routine EM of thin sections and by electron tomography for 3D analysis. There are different levels of correlative microscopy, i.e. the correlation of certain areas, cells, or organelles from light to EM, where photo-oxidation of DAB through GFP allows the highest possible degree--the correlation of specific molecules. PMID:22857926

  16. Dynamical correlations after a quantum quench.

    PubMed

    Essler, Fabian H L; Evangelisti, Stefano; Fagotti, Maurizio

    2012-12-14

    We consider dynamic (non-equal-time) correlation functions of local observables after a quantum quench. We show that, in the absence of long-range interactions in the final Hamiltonian, the dynamics is determined by the same ensemble that describes static (equal-time) correlations. For many integrable models, static correlation functions of local observables after a quantum quench relax to stationary values, which are described by a generalized Gibbs ensemble. The same generalized Gibbs ensemble then determines dynamic correlation functions, and the basic form of the fluctuation dissipation theorem holds, although the absorption and emission spectra are not simply related as in the thermal case. For quenches in the transverse field Ising chain, we derive explicit expressions for the time evolution of dynamic order parameter correlators after a quench. PMID:23368374

  17. Correlated gravitational lensing of the CMB

    E-print Network

    Eric V. Linder

    1996-06-21

    Cosmological inhomogeneities gravitationally deflect radiation propagating from distant sources, transforming the spatial and angular correlation functions of intrinsic source properties. For a gaussian distribution of deflections (e.g. from a primordial gaussian density perturbation spectrum or from the central limit theorem) we calculate the probability distributions for geodesic deviations. If the intrinsic variable is also gaussian, e.g. the large scale velocity flow field or cosmic microwave background temperature anisotropies, then distributions and correlation functions of the observed image sky properties can be obtained. Specialising to CMB temperature fluctuations we rederive simply the influence of independent gravitational lensing on the anisotropy angular correlation function and calculate the new effect of lensing correlated with the anisotropies, e.g. arising from the same primordial gravitational perturbation field. Characteristic magnitudes and scales are given in terms of the density power spectrum. The correlated deflection-temperature effect is shown to be negligible.

  18. Child\\/Adolescent Behavioral and Emotional Problems: Implications of Cross-Informant Correlations for Situational Specificity

    Microsoft Academic Search

    Thomas M. Achenbach; Stephanie H. McConaughy; Catherine T. Howell

    1987-01-01

    Our purpose in this article was to determine the degree of consistency between different informants’ reports of the behavioral\\/emotional problems of subjects aged from 1½ to 19 years. We found 269 samples in 119 studies for meta-analyses of Pearson r s between ratings by parents, teachers, mental health workers, observers, peers, and the subjects themselves. The mean r s between

  19. Motion-sensitive optical correlator using a VanderLugt correlator

    NASA Technical Reports Server (NTRS)

    Liu, Tsuen-Hsi (inventor)

    1994-01-01

    A new type of optical correlator is presented. The correlator performs motion detection or background clutter suppression and correlation simultaneously in a single photorefractive crystal. Additionally, the device is useful for moving target identification and tracking and for stationary clutter rejection. The correlation is of the VanderLugt type, and the motion detection or background clutter suppression is based on the erasing property of photorefractive crystals.

  20. Evaluation and Correlation of Serum Lipid Profile in Oral and Gastrointestinal Cancer Patients

    PubMed Central

    Srinivas, G Vijay; Namala, Srilekha; Ananthaneni, Anuradha; Puneeth, H K; Devi, B Sabitha

    2013-01-01

    Background: High or low cholesterol levels can be perturbing. High cholesterol levels in the blood are associated with increased risk of coronary heart disease whereas insinuation of decreased cholesterol levels remains imprecise. Present study is to evaluate any relationship between the serum lipid levels and the cancer. The purpose of this study is to evaluate the alteration of serum lipid profiles in untreated mucosal cancer patients. Materials & Methods: The study sample consisted of thirty subjects (Group I – 10 gastrointestinal cancer patients, Group II - 10 oral cancer patients and Group III - 10 controls). Fasting lipid profile of blood was evaluated using spectrophotometric kits, with CHOD PAP technique. The values obtained were then statistically analyzed using ANOVA and student ‘ttest. Results: Between Group I and II, Group I comparatively showed more decrease in TC, TG, VLDL and increase in HDL & LDL. P value was significant in only TG. Between Group II and III, TC, HDL and LDL were decreased whereas TG and VLDL were increased in Group II when compared to Group III. TG, LDL, VLDL showed significant p values. Between Group I and III, the variables showed similar results as seen between Group II and III but only LDL showed significant p value. Among the three groups, only LDL showed significant p value (0.048). TC, TG, HDL and VLDL showed non – significant p values. Conclusion: Lower levels of lipid should arouse suspicion for cancer and necessary screening should be done. How to cite this article: Srinivas GV, Namala S, Ananthaneni A, Puneeth HK, Devi BS. Evaluation and Correlation of Serum Lipid Profile in Oral and Gastrointestinal Cancer Patients. J Int Oral Health 2013; 5(6):72-7 . PMID:24453448