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Sample records for resampling-based significance testing

  1. Efficient p-value evaluation for resampling-based tests.

    PubMed

    Yu, Kai; Liang, Faming; Ciampa, Julia; Chatterjee, Nilanjan

    2011-07-01

    The resampling-based test, which often relies on permutation or bootstrap procedures, has been widely used for statistical hypothesis testing when the asymptotic distribution of the test statistic is unavailable or unreliable. It requires repeated calculations of the test statistic on a large number of simulated data sets for its significance level assessment, and thus it could become very computationally intensive. Here, we propose an efficient p-value evaluation procedure by adapting the stochastic approximation Markov chain Monte Carlo algorithm. The new procedure can be used easily for estimating the p-value for any resampling-based test. We show through numeric simulations that the proposed procedure can be 100-500 000 times as efficient (in term of computing time) as the standard resampling-based procedure when evaluating a test statistic with a small p-value (e.g. less than 10( - 6)). With its computational burden reduced by this proposed procedure, the versatile resampling-based test would become computationally feasible for a much wider range of applications. We demonstrate the application of the new method by applying it to a large-scale genetic association study of prostate cancer.

  2. Efficient p-value evaluation for resampling-based tests

    PubMed Central

    Yu, Kai; Liang, Faming; Ciampa, Julia; Chatterjee, Nilanjan

    2011-01-01

    The resampling-based test, which often relies on permutation or bootstrap procedures, has been widely used for statistical hypothesis testing when the asymptotic distribution of the test statistic is unavailable or unreliable. It requires repeated calculations of the test statistic on a large number of simulated data sets for its significance level assessment, and thus it could become very computationally intensive. Here, we propose an efficient p-value evaluation procedure by adapting the stochastic approximation Markov chain Monte Carlo algorithm. The new procedure can be used easily for estimating the p-value for any resampling-based test. We show through numeric simulations that the proposed procedure can be 100–500 000 times as efficient (in term of computing time) as the standard resampling-based procedure when evaluating a test statistic with a small p-value (e.g. less than 10 − 6). With its computational burden reduced by this proposed procedure, the versatile resampling-based test would become computationally feasible for a much wider range of applications. We demonstrate the application of the new method by applying it to a large-scale genetic association study of prostate cancer. PMID:21209154

  3. Introduction to Permutation and Resampling-Based Hypothesis Tests

    ERIC Educational Resources Information Center

    LaFleur, Bonnie J.; Greevy, Robert A.

    2009-01-01

    A resampling-based method of inference--permutation tests--is often used when distributional assumptions are questionable or unmet. Not only are these methods useful for obvious departures from parametric assumptions (e.g., normality) and small sample sizes, but they are also more robust than their parametric counterparts in the presences of…

  4. Introduction to Permutation and Resampling-Based Hypothesis Tests

    ERIC Educational Resources Information Center

    LaFleur, Bonnie J.; Greevy, Robert A.

    2009-01-01

    A resampling-based method of inference--permutation tests--is often used when distributional assumptions are questionable or unmet. Not only are these methods useful for obvious departures from parametric assumptions (e.g., normality) and small sample sizes, but they are also more robust than their parametric counterparts in the presences of…

  5. Statistical properties of an early stopping rule for resampling-based multiple testing.

    PubMed

    Jiang, Hui; Salzman, Julia

    2012-12-01

    Resampling-based methods for multiple hypothesis testing often lead to long run times when the number of tests is large. This paper presents a simple rule that substantially reduces computation by allowing resampling to terminate early on a subset of tests. We prove that the method has a low probability of obtaining a set of rejected hypotheses different from those rejected without early stopping, and obtain error bounds for multiple hypothesis testing. Simulation shows that our approach saves more computation than other available procedures.

  6. Power and stability properties of resampling-based multiple testing procedures with applications to gene oncology studies.

    PubMed

    Li, Dongmei; Dye, Timothy D

    2013-01-01

    Resampling-based multiple testing procedures are widely used in genomic studies to identify differentially expressed genes and to conduct genome-wide association studies. However, the power and stability properties of these popular resampling-based multiple testing procedures have not been extensively evaluated. Our study focuses on investigating the power and stability of seven resampling-based multiple testing procedures frequently used in high-throughput data analysis for small sample size data through simulations and gene oncology examples. The bootstrap single-step minP procedure and the bootstrap step-down minP procedure perform the best among all tested procedures, when sample size is as small as 3 in each group and either familywise error rate or false discovery rate control is desired. When sample size increases to 12 and false discovery rate control is desired, the permutation maxT procedure and the permutation minP procedure perform best. Our results provide guidance for high-throughput data analysis when sample size is small.

  7. Rapid and robust resampling-based multiple-testing correction with application in a genome-wide expression quantitative trait loci study.

    PubMed

    Zhang, Xiang; Huang, Shunping; Sun, Wei; Wang, Wei

    2012-04-01

    Genome-wide expression quantitative trait loci (eQTL) studies have emerged as a powerful tool to understand the genetic basis of gene expression and complex traits. In a typical eQTL study, the huge number of genetic markers and expression traits and their complicated correlations present a challenging multiple-testing correction problem. The resampling-based test using permutation or bootstrap procedures is a standard approach to address the multiple-testing problem in eQTL studies. A brute force application of the resampling-based test to large-scale eQTL data sets is often computationally infeasible. Several computationally efficient methods have been proposed to calculate approximate resampling-based P-values. However, these methods rely on certain assumptions about the correlation structure of the genetic markers, which may not be valid for certain studies. We propose a novel algorithm, rapid and exact multiple testing correction by resampling (REM), to address this challenge. REM calculates the exact resampling-based P-values in a computationally efficient manner. The computational advantage of REM lies in its strategy of pruning the search space by skipping genetic markers whose upper bounds on test statistics are small. REM does not rely on any assumption about the correlation structure of the genetic markers. It can be applied to a variety of resampling-based multiple-testing correction methods including permutation and bootstrap methods. We evaluate REM on three eQTL data sets (yeast, inbred mouse, and human rare variants) and show that it achieves accurate resampling-based P-value estimation with much less computational cost than existing methods. The software is available at http://csbio.unc.edu/eQTL.

  8. Resampling-Based Empirical Bayes Multiple Testing Procedures for Controlling Generalized Tail Probability and Expected Value Error Rates: Focus on the False Discovery Rate and Simulation Study

    PubMed Central

    Dudoit, Sandrine; Gilbert, Houston N.; van der Laan, Mark J.

    2014-01-01

    Summary This article proposes resampling-based empirical Bayes multiple testing procedures for controlling a broad class of Type I error rates, defined as generalized tail probability (gTP) error rates, gTP(q, g) = Pr(g(Vn, Sn) > q), and generalized expected value (gEV) error rates, gEV(g) = E[g(Vn, Sn)], for arbitrary functions g(Vn, Sn) of the numbers of false positives Vn and true positives Sn. Of particular interest are error rates based on the proportion g(Vn, Sn) = Vn/(Vn + Sn) of Type I errors among the rejected hypotheses, such as the false discovery rate (FDR), FDR = E[Vn/(Vn + Sn)]. The proposed procedures offer several advantages over existing methods. They provide Type I error control for general data generating distributions, with arbitrary dependence structures among variables. Gains in power are achieved by deriving rejection regions based on guessed sets of true null hypotheses and null test statistics randomly sampled from joint distributions that account for the dependence structure of the data. The Type I error and power properties of an FDR-controlling version of the resampling-based empirical Bayes approach are investigated and compared to those of widely-used FDR-controlling linear step-up procedures in a simulation study. The Type I error and power trade-off achieved by the empirical Bayes procedures under a variety of testing scenarios allows this approach to be competitive with or outperform the Storey and Tibshirani (2003) linear step-up procedure, as an alternative to the classical Benjamini and Hochberg (1995) procedure. PMID:18932138

  9. Assessing differential expression in two-color microarrays: a resampling-based empirical Bayes approach.

    PubMed

    Li, Dongmei; Le Pape, Marc A; Parikh, Nisha I; Chen, Will X; Dye, Timothy D

    2013-01-01

    Microarrays are widely used for examining differential gene expression, identifying single nucleotide polymorphisms, and detecting methylation loci. Multiple testing methods in microarray data analysis aim at controlling both Type I and Type II error rates; however, real microarray data do not always fit their distribution assumptions. Smyth's ubiquitous parametric method, for example, inadequately accommodates violations of normality assumptions, resulting in inflated Type I error rates. The Significance Analysis of Microarrays, another widely used microarray data analysis method, is based on a permutation test and is robust to non-normally distributed data; however, the Significance Analysis of Microarrays method fold change criteria are problematic, and can critically alter the conclusion of a study, as a result of compositional changes of the control data set in the analysis. We propose a novel approach, combining resampling with empirical Bayes methods: the Resampling-based empirical Bayes Methods. This approach not only reduces false discovery rates for non-normally distributed microarray data, but it is also impervious to fold change threshold since no control data set selection is needed. Through simulation studies, sensitivities, specificities, total rejections, and false discovery rates are compared across the Smyth's parametric method, the Significance Analysis of Microarrays, and the Resampling-based empirical Bayes Methods. Differences in false discovery rates controls between each approach are illustrated through a preterm delivery methylation study. The results show that the Resampling-based empirical Bayes Methods offer significantly higher specificity and lower false discovery rates compared to Smyth's parametric method when data are not normally distributed. The Resampling-based empirical Bayes Methods also offers higher statistical power than the Significance Analysis of Microarrays method when the proportion of significantly differentially

  10. Assessment of Person Fit Using Resampling-Based Approaches

    ERIC Educational Resources Information Center

    Sinharay, Sandip

    2016-01-01

    De la Torre and Deng suggested a resampling-based approach for person-fit assessment (PFA). The approach involves the use of the [math equation unavailable] statistic, a corrected expected a posteriori estimate of the examinee ability, and the Monte Carlo (MC) resampling method. The Type I error rate of the approach was closer to the nominal level…

  11. Assessment of Person Fit Using Resampling-Based Approaches

    ERIC Educational Resources Information Center

    Sinharay, Sandip

    2016-01-01

    De la Torre and Deng suggested a resampling-based approach for person-fit assessment (PFA). The approach involves the use of the [math equation unavailable] statistic, a corrected expected a posteriori estimate of the examinee ability, and the Monte Carlo (MC) resampling method. The Type I error rate of the approach was closer to the nominal level…

  12. Statistical Significance Testing.

    ERIC Educational Resources Information Center

    McLean, James E., Ed.; Kaufman, Alan S., Ed.

    1998-01-01

    The controversy about the use or misuse of statistical significance testing has become the major methodological issue in educational research. This special issue contains three articles that explore the controversy, three commentaries on these articles, an overall response, and three rejoinders by the first three authors. They are: (1)…

  13. A Resampling Based Approach to Optimal Experimental Design for Computer Analysis of a Complex System

    SciTech Connect

    Rutherford, Brian

    1999-08-04

    The investigation of a complex system is often performed using computer generated response data supplemented by system and component test results where possible. Analysts rely on an efficient use of limited experimental resources to test the physical system, evaluate the models and to assure (to the extent possible) that the models accurately simulate the system order investigation. The general problem considered here is one where only a restricted number of system simulations (or physical tests) can be performed to provide additional data necessary to accomplish the project objectives. The levels of variables used for defining input scenarios, for setting system parameters and for initializing other experimental options must be selected in an efficient way. The use of computer algorithms to support experimental design in complex problems has been a topic of recent research in the areas of statistics and engineering. This paper describes a resampling based approach to form dating this design. An example is provided illustrating in two dimensions how the algorithm works and indicating its potential on larger problems. The results show that the proposed approach has characteristics desirable of an algorithmic approach on the simple examples. Further experimentation is needed to evaluate its performance on larger problems.

  14. Resampling-Based Approaches to Study Variation in Morphological Modularity

    PubMed Central

    Fruciano, Carmelo; Franchini, Paolo; Meyer, Axel

    2013-01-01

    Modularity has been suggested to be connected to evolvability because a higher degree of independence among parts allows them to evolve as separate units. Recently, the Escoufier RV coefficient has been proposed as a measure of the degree of integration between modules in multivariate morphometric datasets. However, it has been shown, using randomly simulated datasets, that the value of the RV coefficient depends on sample size. Also, so far there is no statistical test for the difference in the RV coefficient between a priori defined groups of observations. Here, we (1), using a rarefaction analysis, show that the value of the RV coefficient depends on sample size also in real geometric morphometric datasets; (2) propose a permutation procedure to test for the difference in the RV coefficient between a priori defined groups of observations; (3) show, through simulations, that such a permutation procedure has an appropriate Type I error; (4) suggest that a rarefaction procedure could be used to obtain sample-size-corrected values of the RV coefficient; and (5) propose a nearest-neighbor procedure that could be used when studying the variation of modularity in geographic space. The approaches outlined here, readily extendable to non-morphometric datasets, allow study of the variation in the degree of integration between a priori defined modules. A Java application – that will allow performance of the proposed test using a software with graphical user interface – has also been developed and is available at the Morphometrics at Stony Brook Web page (http://life.bio.sunysb.edu/morph/). PMID:23874956

  15. Reconstruction of micron resolution mouse brain surface from large-scale imaging dataset using resampling-based variational model

    PubMed Central

    Li, Jing; Quan, Tingwei; Li, Shiwei; Zhou, Hang; Luo, Qingming; Gong, Hui; Zeng, Shaoqun

    2015-01-01

    Brain surface profile is essential for brain studies, including registration, segmentation of brain structure and drawing neuronal circuits. Recent advances in high-throughput imaging techniques enable imaging whole mouse brain at micron spatial resolution and provide a basis for more fine quantitative studies in neuroscience. However, reconstructing micron resolution brain surface from newly produced neuronal dataset still faces challenges. Most current methods apply global analysis, which are neither applicable to a large imaging dataset nor to a brain surface with an inhomogeneous signal intensity. Here, we proposed a resampling-based variational model for this purpose. In this model, the movement directions of the initial boundary elements are fixed, the final positions of the initial boundary elements that form the brain surface are determined by the local signal intensity. These features assure an effective reconstruction of the brain surface from a new brain dataset. Compared with conventional typical methods, such as level set based method and active contour method, our method significantly increases the recall and precision rates above 97% and is approximately hundreds-fold faster. We demonstrated a fast reconstruction at micron level of the whole brain surface from a large dataset of hundreds of GB in size within 6 hours. PMID:26245266

  16. Reconstruction of micron resolution mouse brain surface from large-scale imaging dataset using resampling-based variational model.

    PubMed

    Li, Jing; Quan, Tingwei; Li, Shiwei; Zhou, Hang; Luo, Qingming; Gong, Hui; Zeng, Shaoqun

    2015-08-06

    Brain surface profile is essential for brain studies, including registration, segmentation of brain structure and drawing neuronal circuits. Recent advances in high-throughput imaging techniques enable imaging whole mouse brain at micron spatial resolution and provide a basis for more fine quantitative studies in neuroscience. However, reconstructing micron resolution brain surface from newly produced neuronal dataset still faces challenges. Most current methods apply global analysis, which are neither applicable to a large imaging dataset nor to a brain surface with an inhomogeneous signal intensity. Here, we proposed a resampling-based variational model for this purpose. In this model, the movement directions of the initial boundary elements are fixed, the final positions of the initial boundary elements that form the brain surface are determined by the local signal intensity. These features assure an effective reconstruction of the brain surface from a new brain dataset. Compared with conventional typical methods, such as level set based method and active contour method, our method significantly increases the recall and precision rates above 97% and is approximately hundreds-fold faster. We demonstrated a fast reconstruction at micron level of the whole brain surface from a large dataset of hundreds of GB in size within 6 hours.

  17. Asymptotic Distributions for Tests of Combined Significance.

    ERIC Educational Resources Information Center

    Becker, Betsy Jane

    This paper discusses distribution theory and power computations for four common "tests of combined significance." These tests are calculated using one-sided sample probabilities or p values from independent studies (or hypothesis tests), and provide an overall significance level for the series of results. Noncentral asymptotic sampling…

  18. Exact significance test for Markov order

    NASA Astrophysics Data System (ADS)

    Pethel, S. D.; Hahs, D. W.

    2014-02-01

    We describe an exact significance test of the null hypothesis that a Markov chain is nth order. The procedure utilizes surrogate data to yield an exact test statistic distribution valid for any sample size. Surrogate data are generated using a novel algorithm that guarantees, per shot, a uniform sampling from the set of sequences that exactly match the nth order properties of the observed data. Using the test, the Markov order of Tel Aviv rainfall data is examined.

  19. The insignificance of statistical significance testing

    USGS Publications Warehouse

    Johnson, Douglas H.

    1999-01-01

    Despite their use in scientific journals such as The Journal of Wildlife Management, statistical hypothesis tests add very little value to the products of research. Indeed, they frequently confuse the interpretation of data. This paper describes how statistical hypothesis tests are often viewed, and then contrasts that interpretation with the correct one. I discuss the arbitrariness of P-values, conclusions that the null hypothesis is true, power analysis, and distinctions between statistical and biological significance. Statistical hypothesis testing, in which the null hypothesis about the properties of a population is almost always known a priori to be false, is contrasted with scientific hypothesis testing, which examines a credible null hypothesis about phenomena in nature. More meaningful alternatives are briefly outlined, including estimation and confidence intervals for determining the importance of factors, decision theory for guiding actions in the face of uncertainty, and Bayesian approaches to hypothesis testing and other statistical practices.

  20. Extraction of mismatch negativity using a resampling-based spatial filtering method

    NASA Astrophysics Data System (ADS)

    Lin, Yanfei; Wu, Wei; Wu, Chaohua; Liu, Baolin; Gao, Xiaorong

    2013-04-01

    Objective. It is currently a challenge to extract the mismatch negativity (MMN) waveform on the basis of a small number of EEG trials, which are typically unbalanced between conditions. Approach. In order to address this issue, a method combining the techniques of resampling and spatial filtering is proposed in this paper. Specifically, the first step of the method, termed ‘resampling difference’, randomly samples the standard and deviant sweeps, and then subtracts standard sweeps from deviant sweeps. The second step of the method employs the spatial filters designed by a signal-to-noise ratio maximizer (SIM) to extract the MMN component. The SIM algorithm can maximize the signal-to-noise ratio for event-related potentials (ERPs) to improve extraction. Simulation data were used to evaluate the influence of three parameters (i.e. trial number, repeated-SIM times and sampling times) on the performance of the proposed method. Main results. Results demonstrated that it was feasible and reliable to extract the MMN waveform using the method. Finally, an oddball paradigm with auditory stimuli of different frequencies was employed to record a few trials (50 trials of deviant sweeps and 250 trials of standard sweeps) of EEG data from 11 adult subjects. Results showed that the method could effectively extract the MMN using the EEG data of each individual subject. Significance. The extracted MMN waveform has a significantly larger peak amplitude and shorter latencies in response to the more deviant stimuli than in response to the less deviant stimuli, which agreed with the MMN properties reported in previous literature using grand-averaged EEG data of multi-subjects.

  1. Tests of Statistical Significance Made Sound

    ERIC Educational Resources Information Center

    Haig, Brian D.

    2017-01-01

    This article considers the nature and place of tests of statistical significance (ToSS) in science, with particular reference to psychology. Despite the enormous amount of attention given to this topic, psychology's understanding of ToSS remains deficient. The major problem stems from a widespread and uncritical acceptance of null hypothesis…

  2. Innovative trend significance test and applications

    NASA Astrophysics Data System (ADS)

    Şen, Zekai

    2017-02-01

    Hydro-climatological time series might embed characteristics of past changes concerning climate variability in terms of shifts, cyclic fluctuations, and more significantly in the form of trends. Identification of such features from the available records is one of the prime tasks of hydrologists, climatologists, applied statisticians, or experts in related topics. Although there are different trend identification and significance tests in the literature, they require restrictive assumptions, which may not be existent in the structure of hydro-climatological time series. In this paper, a method is suggested with statistical significance test for trend identification in an innovative manner. This method has non-parametric basis without any restrictive assumption, and its application is rather simple with the concept of sub-series comparisons that are extracted from the main time series. The method provides privilege for selection of sub-temporal half periods for the comparison and, finally, generates trend on objective and quantitative manners. The necessary statistical equations are derived for innovative trend identification and statistical significance test application. The application of the proposed methodology is suggested for three time series from different parts of the world including Southern New Jersey annual temperature, Danube River annual discharge, and Tigris River Diyarbakir meteorology station annual total rainfall records. Each record has significant trend with increasing type in the New Jersey case, whereas in other two cases, decreasing trends exist.

  3. Innovative trend significance test and applications

    NASA Astrophysics Data System (ADS)

    Şen, Zekai

    2015-11-01

    Hydro-climatological time series might embed characteristics of past changes concerning climate variability in terms of shifts, cyclic fluctuations, and more significantly in the form of trends. Identification of such features from the available records is one of the prime tasks of hydrologists, climatologists, applied statisticians, or experts in related topics. Although there are different trend identification and significance tests in the literature, they require restrictive assumptions, which may not be existent in the structure of hydro-climatological time series. In this paper, a method is suggested with statistical significance test for trend identification in an innovative manner. This method has non-parametric basis without any restrictive assumption, and its application is rather simple with the concept of sub-series comparisons that are extracted from the main time series. The method provides privilege for selection of sub-temporal half periods for the comparison and, finally, generates trend on objective and quantitative manners. The necessary statistical equations are derived for innovative trend identification and statistical significance test application. The application of the proposed methodology is suggested for three time series from different parts of the world including Southern New Jersey annual temperature, Danube River annual discharge, and Tigris River Diyarbakir meteorology station annual total rainfall records. Each record has significant trend with increasing type in the New Jersey case, whereas in other two cases, decreasing trends exist.

  4. Significance testing as perverse probabilistic reasoning

    PubMed Central

    2011-01-01

    Truth claims in the medical literature rely heavily on statistical significance testing. Unfortunately, most physicians misunderstand the underlying probabilistic logic of significance tests and consequently often misinterpret their results. This near-universal misunderstanding is highlighted by means of a simple quiz which we administered to 246 physicians at two major academic hospitals, on which the proportion of incorrect responses exceeded 90%. A solid understanding of the fundamental concepts of probability theory is becoming essential to the rational interpretation of medical information. This essay provides a technically sound review of these concepts that is accessible to a medical audience. We also briefly review the debate in the cognitive sciences regarding physicians' aptitude for probabilistic inference. PMID:21356064

  5. Genetic Plasticity of V Genes Under Somatic Hypermutation: Statistical Analyses Using a New Resampling-Based Methodology

    PubMed Central

    Oprea, Mihaela; Kepler, Thomas B.

    1999-01-01

    Evidence for somatic hypermutation of immunoglobulin genes has been observed in all of the species in which immunoglobulins have been found. Previous studies have suggested that codon usage in immunoglobulin variable (V) region genes is such that the sequence-specificity of somatic hypermutation results in greater mutability in complementarity-determining regions of the gene than in the framework regions. We have developed a new resampling-based methodology to explore genetic plasticity in individual V genes and in V gene families in a statistically meaningful way. We determine what factors contribute to this mutability difference and characterize the strength of selection for this effect. We find that although the codon usage in immunoglobulin V genes renders them distinct among translationally equivalent sequences with random codon usage, they are nevertheless not optimal in this regard. We find that the mutability patterns in a number of species are similar to those we find for human sequences. Interestingly, sheep sequences show extremely strong mutability differences, consistent with the role of somatic hypermutation in the diversification of primary antibody repertoire in these animals. Human TCR Vβ sequences resemble immunoglobulin in mutability pattern, suggesting one of several alternatives, that hypermutation is functionally operating in TCR, that it was once operating in TCR or in the common precursor of TCR and immunoglobulin, or that the hypermutation mechanism has evolved to exploit the codon usage in immunoglobulin (and fortuitously, TCR) rather than vice-versa. Our findings provide support to the hypothesis that somatic hypermutation appeared very early in the phylogeny of immune systems, that it is, to a large extent, shared between species, and that it makes an essential contribution to the generation of the antibody repertoire. PMID:10613852

  6. Significance testing testate amoeba water table reconstructions

    NASA Astrophysics Data System (ADS)

    Payne, Richard J.; Babeshko, Kirill V.; van Bellen, Simon; Blackford, Jeffrey J.; Booth, Robert K.; Charman, Dan J.; Ellershaw, Megan R.; Gilbert, Daniel; Hughes, Paul D. M.; Jassey, Vincent E. J.; Lamentowicz, Łukasz; Lamentowicz, Mariusz; Malysheva, Elena A.; Mauquoy, Dmitri; Mazei, Yuri; Mitchell, Edward A. D.; Swindles, Graeme T.; Tsyganov, Andrey N.; Turner, T. Edward; Telford, Richard J.

    2016-04-01

    Transfer functions are valuable tools in palaeoecology, but their output may not always be meaningful. A recently-developed statistical test ('randomTF') offers the potential to distinguish among reconstructions which are more likely to be useful, and those less so. We applied this test to a large number of reconstructions of peatland water table depth based on testate amoebae. Contrary to our expectations, a substantial majority (25 of 30) of these reconstructions gave non-significant results (P > 0.05). The underlying reasons for this outcome are unclear. We found no significant correlation between randomTF P-value and transfer function performance, the properties of the training set and reconstruction, or measures of transfer function fit. These results give cause for concern but we believe it would be extremely premature to discount the results of non-significant reconstructions. We stress the need for more critical assessment of transfer function output, replication of results and ecologically-informed interpretation of palaeoecological data.

  7. Significance testing for correlated binary outcome data.

    PubMed

    Rosner, B; Milton, R C

    1988-06-01

    Multiple logistic regression is a commonly used multivariate technique for analyzing data with a binary outcome. One assumption needed for this method of analysis is the independence of outcome for all sample points in a data set. In ophthalmologic data and other types of correlated binary data, this assumption is often grossly violated and the validity of the technique becomes an issue. A technique has been developed (Rosner, 1984) that utilizes a polychotomous logistic regression model to allow one to look at multiple exposure variables in the context of a correlated binary data structure. This model is an extension of the beta-binomial model, which has been widely used to model correlated binary data when no covariates are present. In this paper, a relationship is developed between the two techniques, whereby it is shown that use of ordinary logistic regression in the presence of correlated binary data can result in true significance levels that are considerably larger than nominal levels in frequently encountered situations. This relationship is explored in detail in the case of a single dichotomous exposure variable. In this case, the appropriate test statistic can be expressed as an adjusted chi-square statistic based on the 2 X 2 contingency table relating exposure to outcome. The test statistic is easily computed as a function of the ordinary chi-square statistic and the correlation between eyes (or more generally between cluster members) for outcome and exposure, respectively. This generalizes some previous results obtained by Koval and Donner (1987, in Festschrift for V. M. Joshi, I. B. MacNeill (ed.), Vol. V, 199-224.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Correcting a Significance Test for Clustering

    ERIC Educational Resources Information Center

    Hedges, Larry V.

    2007-01-01

    A common mistake in analysis of cluster randomized trials is to ignore the effect of clustering and analyze the data as if each treatment group were a simple random sample. This typically leads to an overstatement of the precision of results and anticonservative conclusions about precision and statistical significance of treatment effects. This…

  9. Statistical significance testing and clinical trials.

    PubMed

    Krause, Merton S

    2011-09-01

    The efficacy of treatments is better expressed for clinical purposes in terms of these treatments' outcome distributions and their overlapping rather than in terms of the statistical significance of these distributions' mean differences, because clinical practice is primarily concerned with the outcome of each individual client rather than with the mean of the variety of outcomes in any group of clients. Reports of the obtained outcome distributions for the comparison groups of all competently designed and executed randomized clinical trials should be publicly available no matter what the statistical significance of the mean differences among these groups, because all of these studies' outcome distributions provide clinically useful information about the efficacy of the treatments compared.

  10. Advances in Significance Testing for Cluster Detection

    NASA Astrophysics Data System (ADS)

    Coleman, Deidra Andrea

    Over the past two decades, much attention has been given to data driven project goals such as the Human Genome Project and the development of syndromic surveillance systems. A major component of these types of projects is analyzing the abundance of data. Detecting clusters within the data can be beneficial as it can lead to the identification of specified sequences of DNA nucleotides that are related to important biological functions or the locations of epidemics such as disease outbreaks or bioterrorism attacks. Cluster detection techniques require efficient and accurate hypothesis testing procedures. In this dissertation, we improve upon the hypothesis testing procedures for cluster detection by enhancing distributional theory and providing an alternative method for spatial cluster detection using syndromic surveillance data. In Chapter 2, we provide an efficient method to compute the exact distribution of the number and coverage of h-clumps of a collection of words. This method involves defining a Markov chain using a minimal deterministic automaton to reduce the number of states needed for computation. We allow words of the collection to contain other words of the collection making the method more general. We use our method to compute the distributions of the number and coverage of h-clumps in the Chi motif of H. influenza.. In Chapter 3, we provide an efficient algorithm to compute the exact distribution of multiple window discrete scan statistics for higher-order, multi-state Markovian sequences. This algorithm involves defining a Markov chain to efficiently keep track of probabilities needed to compute p-values of the statistic. We use our algorithm to identify cases where the available approximation does not perform well. We also use our algorithm to detect unusual clusters of made free throw shots by National Basketball Association players during the 2009-2010 regular season. In Chapter 4, we give a procedure to detect outbreaks using syndromic

  11. An optimal property of the repeated significance test

    PubMed Central

    Lerche, Hans Rudolf

    1986-01-01

    It is shown that the repeated significance test is a Bayes test for testing sequentially the sign of the drift of a Brownian motion. Its relation to Wald's sequential probability ratio test is studied. PMID:16593662

  12. A Priori and A Posteriori Tests of Significance for Koppa.

    ERIC Educational Resources Information Center

    Warner, Lyle G.; Gray, Louis

    1978-01-01

    The Koppa coefficient is a measure of association between two variables which have been measured dichotomously. Significance tests for comparing Koppa coefficients from multiple samples are presented. (JKS)

  13. Statistical significance test for transition matrices of atmospheric Markov chains

    NASA Technical Reports Server (NTRS)

    Vautard, Robert; Mo, Kingtse C.; Ghil, Michael

    1990-01-01

    Low-frequency variability of large-scale atmospheric dynamics can be represented schematically by a Markov chain of multiple flow regimes. This Markov chain contains useful information for the long-range forecaster, provided that the statistical significance of the associated transition matrix can be reliably tested. Monte Carlo simulation yields a very reliable significance test for the elements of this matrix. The results of this test agree with previously used empirical formulae when each cluster of maps identified as a distinct flow regime is sufficiently large and when they all contain a comparable number of maps. Monte Carlo simulation provides a more reliable way to test the statistical significance of transitions to and from small clusters. It can determine the most likely transitions, as well as the most unlikely ones, with a prescribed level of statistical significance.

  14. Statistical Significance Testing Should Be Discontinued in Mathematics Education Research.

    ERIC Educational Resources Information Center

    Menon, Rama

    1993-01-01

    Discusses five common myths about statistical significance testing (SST), the possible erroneous and harmful contributions of SST to educational research, and suggested alternatives to SST for mathematics education research. (Contains 61 references.) (MKR)

  15. Test Design Considerations for Students with Significant Cognitive Disabilities

    ERIC Educational Resources Information Center

    Anderson, Daniel; Farley, Dan; Tindal, Gerald

    2015-01-01

    Students with significant cognitive disabilities present an assessment dilemma that centers on access and validity in large-scale testing programs. Typically, access is improved by eliminating construct-irrelevant barriers, while validity is improved, in part, through test standardization. In this article, one state's alternate assessment data…

  16. Testing the Difference of Correlated Agreement Coefficients for Statistical Significance

    ERIC Educational Resources Information Center

    Gwet, Kilem L.

    2016-01-01

    This article addresses the problem of testing the difference between two correlated agreement coefficients for statistical significance. A number of authors have proposed methods for testing the difference between two correlated kappa coefficients, which require either the use of resampling methods or the use of advanced statistical modeling…

  17. Testing the Difference of Correlated Agreement Coefficients for Statistical Significance

    ERIC Educational Resources Information Center

    Gwet, Kilem L.

    2016-01-01

    This article addresses the problem of testing the difference between two correlated agreement coefficients for statistical significance. A number of authors have proposed methods for testing the difference between two correlated kappa coefficients, which require either the use of resampling methods or the use of advanced statistical modeling…

  18. Test Design Considerations for Students with Significant Cognitive Disabilities

    ERIC Educational Resources Information Center

    Anderson, Daniel; Farley, Dan; Tindal, Gerald

    2015-01-01

    Students with significant cognitive disabilities present an assessment dilemma that centers on access and validity in large-scale testing programs. Typically, access is improved by eliminating construct-irrelevant barriers, while validity is improved, in part, through test standardization. In this article, one state's alternate assessment data…

  19. 40 CFR Appendix IV to Part 265 - Tests for Significance

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... difference test for pH must be a two-tailed Student's t-test at the overall 0.01 level of significance. The... changes in the concentration or value of an indicator parameter in periodic ground-water samples when compared to the initial background concentration or value of that indicator -parameter. The comparison must...

  20. 40 CFR Appendix IV to Part 265 - Tests for Significance

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... difference test for pH must be a two-tailed Student's t-test at the overall 0.01 level of significance. The... changes in the concentration or value of an indicator parameter in periodic ground-water samples when compared to the initial background concentration or value of that indicator -parameter. The comparison must...

  1. 40 CFR Appendix IV to Part 265 - Tests for Significance

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... difference test for pH must be a two-tailed Student's t-test at the overall 0.01 level of significance. The... changes in the concentration or value of an indicator parameter in periodic ground-water samples when compared to the initial background concentration or value of that indicator -parameter. The comparison must...

  2. Your Chi-Square Test Is Statistically Significant: Now What?

    ERIC Educational Resources Information Center

    Sharpe, Donald

    2015-01-01

    Applied researchers have employed chi-square tests for more than one hundred years. This paper addresses the question of how one should follow a statistically significant chi-square test result in order to determine the source of that result. Four approaches were evaluated: calculating residuals, comparing cells, ransacking, and partitioning. Data…

  3. Your Chi-Square Test Is Statistically Significant: Now What?

    ERIC Educational Resources Information Center

    Sharpe, Donald

    2015-01-01

    Applied researchers have employed chi-square tests for more than one hundred years. This paper addresses the question of how one should follow a statistically significant chi-square test result in order to determine the source of that result. Four approaches were evaluated: calculating residuals, comparing cells, ransacking, and partitioning. Data…

  4. 40 CFR Appendix IV to Part 265 - Tests for Significance

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... changes in the concentration or value of an indicator parameter in periodic ground-water samples when... then be compared to the value of the t-statistic found in a table for t-test of significance at the specified level of significance. A calculated value of t which exceeds the value of t found in the table...

  5. 40 CFR Appendix IV to Part 265 - Tests for Significance

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... changes in the concentration or value of an indicator parameter in periodic ground-water samples when... then be compared to the value of the t-statistic found in a table for t-test of significance at the specified level of significance. A calculated value of t which exceeds the value of t found in the table...

  6. An improved Hochberg procedure for multiple tests of significance.

    PubMed

    Rom, Dror M

    2013-02-01

    We propose a simple modification of Hochberg's step-up Bonferroni procedure for multiple tests of significance. The proposed procedure is always more powerful than Hochberg's procedure for more than two tests, and is more powerful than Hommel's procedure for three and four tests. A numerical analysis of the new procedure indicates that its Type I error is controlled under independence of the test statistics, at a level equal to or just below the nominal Type I error. Examination of various non-null configurations of hypotheses shows that the modified procedure has a power advantage over Hochberg's procedure which increases in relationship to the number of false hypotheses.

  7. Evaluating clinical significance: incorporating robust statistics with normative comparison tests.

    PubMed

    van Wieringen, Katrina; Cribbie, Robert A

    2014-05-01

    The purpose of this study was to evaluate a modified test of equivalence for conducting normative comparisons when distribution shapes are non-normal and variances are unequal. A Monte Carlo study was used to compare the empirical Type I error rates and power of the proposed Schuirmann-Yuen test of equivalence, which utilizes trimmed means, with that of the previously recommended Schuirmann and Schuirmann-Welch tests of equivalence when the assumptions of normality and variance homogeneity are satisfied, as well as when they are not satisfied. The empirical Type I error rates of the Schuirmann-Yuen were much closer to the nominal α level than those of the Schuirmann or Schuirmann-Welch tests, and the power of the Schuirmann-Yuen was substantially greater than that of the Schuirmann or Schuirmann-Welch tests when distributions were skewed or outliers were present. The Schuirmann-Yuen test is recommended for assessing clinical significance with normative comparisons.

  8. Token swap test of significance for serial medical data bases.

    PubMed

    Moore, G W; Hutchins, G M; Miller, R E

    1986-02-01

    Established tests of statistical significance are based upon the concept that observed data are drawn randomly from a larger, perhaps infinite source population. The significance value, p, is the probability that the observations are drawn from a source population satisfying the null hypothesis; if p is small enough (less than 5 percent, 1 percent, etc.), then the null hypothesis is rejected. Serial medical data bases, such as a hospital clinic intake or autopsy case accessions, often do not have an identifiable source population from which they are randomly drawn. In an effort to make a reasonable interpretation of these less-than-ideal data, this report introduces a "token swap" test of significance, in which the usual paradigm of repeated drawing from a source population is replaced by a paradigm or misclassification within the observed data themselves. The token swap test consists of rearranging the data into a balanced distribution, and determining the disparity between the observed and the balanced distribution of data. In a two-by-two contingency table, patients are represented as "tokens" distributed into four "cells." Significance is determined by the proportion of "token swaps" that are able to transform the balanced table into the observed table. The token swap test was applied to three series of autopsy observations, and gave results roughly comparable to the corresponding (two-tail) chi-square and one-tail Fisher exact tests. The token swap test of significance may be a useful alternative to classic statistical tests when the limiting assumptions of a retrospective, serial medical data base are present.

  9. Predictive Value of Screening Tests for Visually Significant Eye Disease

    PubMed Central

    Kopplin, Laura J.; Mansberger, Steven L.

    2017-01-01

    Purpose To determine the predictive value of ophthalmic screening tests with visually significant eye disease in a cohort of American Indian/Alaskan Natives from the Pacific Northwest. Design Validity assessment of a possible screening protocol. Methods Ophthalmic technicians performed a screening examination including medical and ocular history, best-corrected visual acuity, limbal anterior chamber depth assessment, frequency doubling technology perimetry (FDT, C-20-5), confocal scanning laser ophthalmoscopy, nonmydriatic digital photography, and tonometry on 429 participants. An ophthalmologist performed a comprehensive eye exam on subjects with one or more abnormal screening tests and a random selection of those with normal screening tests. We used univariate and multivariate logistic regression to determine the association between abnormal screening test results and visually significant eye disease. We also determined the predictive value of screening tests with ocular disease. Results Univariate analysis identified history of eye disease or diabetes mellitus (p<.001), visual acuity <20/40 (p<.001), abnormal/poor quality confocal scanning laser ophthalmoscopy (p<.001), abnormal FDT (p<.001), and abnormal/poor quality non-mydriatic imaging (p<.001) as associated with visually significant eye disease. A multivariate analysis found visually significant eye disease to be associated (p<.001; receiver operating curve area= .827, negative predictive value=84%) with four screening tests: visual acuity <20/40, abnormal/poor quality non-mydriatic imaging, abnormal FDT and abnormal/poor quality confocal scanning laser ophthalmoscopy. Conclusions Ophthalmic technicians performing a subset of screening tests may provide an accurate and efficient means of screening for eye disease in an American Indian/Alaskan Native population. Confirmation of these results in other populations, particularly those with a different profile of disease prevalence is needed. PMID:26052087

  10. Predictive value of screening tests for visually significant eye disease.

    PubMed

    Kopplin, Laura J; Mansberger, Steven L

    2015-09-01

    To determine the predictive value of ophthalmic screening tests with visually significant eye disease in a cohort of American Indian/Alaskan Natives from the Pacific Northwest. Validity assessment of a possible screening protocol. Ophthalmic technicians performed a screening examination including medical and ocular history, best-corrected visual acuity, limbal anterior chamber depth assessment, frequency-doubling technology perimetry (FDT, C-20-5), confocal scanning laser ophthalmoscopy, nonmydriatic digital photography, and tonometry on 429 participants. An ophthalmologist performed a comprehensive eye examination on subjects with 1 or more abnormal screening tests and a random selection of those with normal screening tests. We used univariate and multivariate logistic regression to determine the association between abnormal screening test results and visually significant eye disease. We also determined the predictive value of screening tests with ocular disease. Univariate analysis identified history of eye disease or diabetes mellitus (P < .001), visual acuity <20/40 (P < .001), abnormal/poor-quality confocal scanning laser ophthalmoscopy (P < .001), abnormal FDT (P < .001), and abnormal/poor-quality nonmydriatic imaging (P < .001) as associated with visually significant eye disease. A multivariate analysis found visually significant eye disease to be associated (P < .001; receiver operating characteristic curve area = 0.827, negative predictive value = 84%) with 4 screening tests: visual acuity <20/40, abnormal/poor-quality nonmydriatic imaging, abnormal FDT, and abnormal/poor-quality confocal scanning laser ophthalmoscopy. Ophthalmic technicians performing a subset of screening tests may provide an accurate and efficient means of screening for eye disease in an American Indian/Alaskan Native population. Confirmation of these results in other populations, particularly those with a different profile of disease prevalence, is needed. Copyright © 2015 Elsevier

  11. The Use of Meta-Analytic Statistical Significance Testing

    ERIC Educational Resources Information Center

    Polanin, Joshua R.; Pigott, Terri D.

    2015-01-01

    Meta-analysis multiplicity, the concept of conducting multiple tests of statistical significance within one review, is an underdeveloped literature. We address this issue by considering how Type I errors can impact meta-analytic results, suggest how statistical power may be affected through the use of multiplicity corrections, and propose how…

  12. The Use of Meta-Analytic Statistical Significance Testing

    ERIC Educational Resources Information Center

    Polanin, Joshua R.; Pigott, Terri D.

    2015-01-01

    Meta-analysis multiplicity, the concept of conducting multiple tests of statistical significance within one review, is an underdeveloped literature. We address this issue by considering how Type I errors can impact meta-analytic results, suggest how statistical power may be affected through the use of multiplicity corrections, and propose how…

  13. Advances in Testing the Statistical Significance of Mediation Effects

    ERIC Educational Resources Information Center

    Mallinckrodt, Brent; Abraham, W. Todd; Wei, Meifen; Russell, Daniel W.

    2006-01-01

    P. A. Frazier, A. P. Tix, and K. E. Barron (2004) highlighted a normal theory method popularized by R. M. Baron and D. A. Kenny (1986) for testing the statistical significance of indirect effects (i.e., mediator variables) in multiple regression contexts. However, simulation studies suggest that this method lacks statistical power relative to some…

  14. Defending the Logic of Significance Testing: A Response to Gorard

    ERIC Educational Resources Information Center

    Neale, Dave

    2015-01-01

    Recently, Stephen Gorard has outlined strong objections to the use of significance testing in social research. He has argued, first, that as the samples used in social research are almost always non-random it is not possible to use inferential statistical techniques and, second, that even if a truly random sample were achieved, the logic behind…

  15. Defending the Logic of Significance Testing: A Response to Gorard

    ERIC Educational Resources Information Center

    Neale, Dave

    2015-01-01

    Recently, Stephen Gorard has outlined strong objections to the use of significance testing in social research. He has argued, first, that as the samples used in social research are almost always non-random it is not possible to use inferential statistical techniques and, second, that even if a truly random sample were achieved, the logic behind…

  16. Significance testing - are we ready yet to abandon its use?

    PubMed

    The, Bertram

    2011-11-01

    Understanding of the damaging effects of significance testing has steadily grown. Reporting p values without dichotomizing the result to be significant or not, is not the solution. Confidence intervals are better, but are troubled by a non-intuitive interpretation, and are often misused just to see whether the null value lies within the interval. Bayesian statistics provide an alternative which solves most of these problems. Although criticized for relying on subjective models, the interpretation of a Bayesian posterior probability is more intuitive than the interpretation of a p value, and seems to be closest to intuitive patterns of human decision making. Another alternative could be using confidence interval functions (or p value functions) to display a continuum of intervals at different levels of confidence around a point estimate. Thus, better alternatives to significance testing exist. The reluctance to abandon this practice might be both preference of clinging to old habits as well as the unfamiliarity with better methods. Authors might question if using less commonly exercised, though superior, techniques will be well received by the editors, reviewers and the readership. A joint effort will be needed to abandon significance testing in clinical research in the future.

  17. Testing the aesthetic significance of the golden-section rectangle.

    PubMed

    Russell, P A

    2000-01-01

    The aesthetic significance of the golden-section rectangle was tested in two studies designed to obviate some of the criticisms of earlier experiments. In the first, employing the method of use, the mean sides-ratios of samples of paintings from five subject-matter categories (landscape, still life, head-and-shoulders portrait, upper-body portrait, full-length portrait) provided no evidence for the significance of the golden section. However, the sides ratio of portraits varied between categories in ways that were consistent with the requirements of the proportions of the subject matter. In the second study, using the method of production, participants produced the most pleasing four-sided shape, under four instruction conditions. Under a 'portrait painting' condition and a 'landscape painting' condition, the mean sides-ratios differed significantly from the golden section. Under two 'context free' geometric shape conditions--horizontal rectangle and vertical rectangle--the mean sides-ratio approximated the golden section. The results are discussed in terms of the methodological requirements for a valid test of the aesthetic significance of the golden section and the possibility that this ratio may indeed have special significance.

  18. Coagulation tests show significant differences in patients with breast cancer.

    PubMed

    Tas, Faruk; Kilic, Leyla; Duranyildiz, Derya

    2014-06-01

    Activated coagulation and fibrinolytic system in cancer patients is associated with tumor stroma formation and metastasis in different cancer types. The aim of this study is to explore the correlation of blood coagulation assays for various clinicopathologic factors in breast cancer patients. A total of 123 female breast cancer patients were enrolled into the study. All the patients were treatment naïve. Pretreatment blood coagulation tests including PT, APTT, PTA, INR, D-dimer, fibrinogen levels, and platelet counts were evaluated. Median age of diagnosis was 51 years old (range 26-82). Twenty-two percent of the group consisted of metastatic breast cancer patients. The plasma level of all coagulation tests revealed statistically significant difference between patient and control group except for PT (p<0.001 for all variables except for PT; p=0.08). Elderly age (>50 years) was associated with higher D-dimer levels (p=0.003). Metastatic patients exhibited significantly higher D-dimer values when compared with early breast cancer patients (p=0.049). Advanced tumor stage (T3 and T4) was associated with higher INR (p=0.05) and lower PTA (p=0.025). In conclusion, coagulation tests show significant differences in patients with breast cancer.

  19. Optimizing significance testing of astronomical forcing in cyclostratigraphy

    NASA Astrophysics Data System (ADS)

    Kemp, David B.

    2016-12-01

    The recognition of astronomically forced (Milankovitch) climate cycles in geological archives marked a major advance in Earth science, revealing a heartbeat within the climate system of general importance and key utility. Power spectral analysis is the primary tool used to facilitate identification of astronomical cycles in stratigraphic data, but commonly employed methods for testing the statistical significance of relatively high narrow-band variance of potential astronomical origin in spectra have been criticized for inadequately balancing the respective probabilities of type I (false positive) and type II (false negative) errors. This has led to suggestions that the importance of astronomical forcing in Earth history is overstated. It can be readily demonstrated, however, that the imperfect nature of the stratigraphic record and the quasiperiodicity of astronomical cycles sets an upper limit on the attainable significance of astronomical signals. Optimized significance testing is that which minimizes the combined probability of type I and type II errors. Numerical simulations of stratigraphically preserved astronomical signals suggest that optimum significance levels at which to reject a null hypothesis of no astronomical forcing are between 0.01 and 0.001 (i.e., 99-99.9% confidence level). This is lower than commonly employed in the literature (90-99% confidence levels). Nevertheless, in consonance with the emergent view from other scientific disciplines, fixed-value null hypothesis significance testing of power spectra is implicitly ill suited to demonstrating astronomical forcing, and the use of spectral analysis remains a difficult and subjective endeavor in the absence of additional supporting evidence.

  20. Significance of the blood beryllium lymphocyte proliferation test

    SciTech Connect

    Newman, L.S.

    1996-10-01

    The blood beryllium lymphocyte proliferation test (BeLPT) is an in vitro measure of the beryllium antigen-specific cell-mediated immune response. This response to beryllium is now understood to play a central role in the immunopathogenesis of chronic beryllium disease (CBD). Although there remain some unresolved methodologic issues with testing, the blood BeLPT has already undergone sufficient development and field assessment to lead to a number of important conclusions: (a) The BeLPT identifies beryllium sensitization and CBD earlier and better than any other clinical test presently available. (b) The CBD cases identified with the blood test are clinically significant. (c) A subset of the people identified by the BeLPT who do not yet have clinical disease will progress and require treatment with corticosteroids for impairing illness. (d) The BeLPT can be used to improve clinical diagnostic accuracy and to correct mistaken diagnoses. (e) The blood test can be used in screening large numbers of exposed workers because it is sensitive and specific and has high positive and negative predictive value for CBD. (f) In every workforce studied to date, the BeLPT has identified beryllium sensitization and CBD that had been missed by conventional screening efforts. (g) Worker populations that have been characterized using the BeLPT can help to elucidate the role of exposure genetics and dysregulated inflammation in the genesis of occupational lung disease. 28 refs., 1 tab.

  1. Significance testing of orbital forcing in deep time

    NASA Astrophysics Data System (ADS)

    Kemp, David

    2016-04-01

    The recognition of orbitally forced (Milankovitch) climate cycles in geological archives marked a paradigm shift in Earth science, revealing a heartbeat within the climate system of general importance and key utility. Resolving orbital cycles in stratigraphic data is, however, problematic owing to the imperfect stratigraphic preservation of climate signals, the masking effects of non-periodic variance, and uncertainties in the expected responses of proxy records to climate change. Power spectral analysis is the primary tool used to facilitate identification of orbital cycles in stratigraphic data, but commonly employed methods for testing the significance of relatively high narrow-band variance of potential orbital origin in spectra have been criticised for inadequately balancing the respective probabilities of type I (false positive) and type II (false negative) errors. This has led to suggestions that the importance of orbital forcing in deep time is overstated [1]. It can be readily demonstrated, however, that the imperfect nature of the stratigraphic record sets an upper limit on the attainable significance of orbital signals. Optimised significance testing is that which minimises the sum of type I and type II errors [2]. Numerical simulations of stratigraphically preserved orbital signals suggest that optimum significance levels at which to reject a null hypothesis of no orbital forcing cluster between 99% and 99.9%. This is lower than recently advocated [1], but higher than the 90-99% levels most commonly employed in the literature. Nevertheless, in consonance with the emergent view from other scientific disciplines, fixed-value null hypothesis significance testing of power spectra is likely ill suited to verifying orbital forcing. In part, this is because the experiments also indicate that the combined probability of making an error in the acceptance or rejection of an orbital hypothesis may be rather high for typical stratigraphic data, and hence the use of

  2. Measures, Uncertainties, and Significance Test in Operational ROC Analysis

    PubMed Central

    Wu, Jin Chu; Martin, Alvin F.; Kacker, Raghu N.

    2011-01-01

    In receiver operating characteristic (ROC) analysis, the sampling variability can result in uncertainties of performance measures. Thus, while evaluating and comparing the performances of algorithms, the measurement uncertainties must be taken into account. The key issue is how to calculate the uncertainties of performance measures in ROC analysis. Our ultimate goal is to perform the significance test in evaluation and comparison using the standard errors computed. From the operational perspective, based on fingerprint-image matching algorithms on large datasets, the measures and their uncertainties are investigated in the three scenarios: 1) the true accept rate (TAR) of genuine scores at a specified false accept rate (FAR) of impostor scores, 2) the TAR and FAR at a given threshold, and 3) the equal error rate. The uncertainties of measures are calculated using the nonparametric two-sample bootstrap based on our extensive studies of bootstrap variability on large datasets. The significance test is carried out to determine whether the difference between the performance of one algorithm and a hypothesized value, or the difference between the performances of two algorithms where the correlation is taken into account is statistically significant. Examples are provided. PMID:26989582

  3. Significance of tests of iron nutrition in pregnancy

    PubMed Central

    Metz, J.; Turchetti, L.; Combrink, B.; Krawitz, S.

    1966-01-01

    Tests of iron and folate nutrition have been carried out in early pregnancy and at delivery in 63 Bantu females. Accepted normal values for serum iron, and percentage saturation of transferrin, but not for unsaturated iron-binding capacity, for non-pregnant subjects were found to apply equally well in pregnancy. Concomitant folate deficiency in early pregnancy did not render tests of iron deficiency less valid. The unsaturated iron-binding capacity, percentage saturation, and marrow iron stores in early pregnancy all showed a significant correlation with the haemoglobin value at term. Patients with normal marrow iron stores and a percentage saturation of transferrin of 20 or more at or before the 24th week are unlikely to become anaemic from iron deficiency during pregnancy. PMID:5909700

  4. Significant Inter-Test Reliability across Approximate Number System Assessments

    PubMed Central

    DeWind, Nicholas K.; Brannon, Elizabeth M.

    2016-01-01

    The approximate number system (ANS) is the hypothesized cognitive mechanism that allows adults, infants, and animals to enumerate large sets of items approximately. Researchers usually assess the ANS by having subjects compare two sets and indicate which is larger. Accuracy or Weber fraction is taken as an index of the acuity of the system. However, as Clayton et al. (2015) have highlighted, the stimulus parameters used when assessing the ANS vary widely. In particular, the numerical ratio between the pairs, and the way in which non-numerical features are varied often differ radically between studies. Recently, Clayton et al. (2015) found that accuracy measures derived from two commonly used stimulus sets are not significantly correlated. They argue that a lack of inter-test reliability threatens the validity of the ANS construct. Here we apply a recently developed modeling technique to the same data set. The model, by explicitly accounting for the effect of numerical ratio and non-numerical features, produces dependent measures that are less perturbed by stimulus protocol. Contrary to their conclusion we find a significant correlation in Weber fraction across the two stimulus sets. Nevertheless, in agreement with Clayton et al. (2015) we find that different protocols do indeed induce differences in numerical acuity and the degree of influence of non-numerical stimulus features. These findings highlight the need for a systematic investigation of how protocol idiosyncrasies affect ANS assessments. PMID:27014126

  5. Significant issues in proof testing: A critical appraisal

    NASA Technical Reports Server (NTRS)

    Chell, G. G.; Mcclung, R. C.; Russell, D. A.; Chang, K. J.; Donnelly, B.

    1994-01-01

    Issues which impact on the interpretation and quantification of proof test benefits are reviewed. The importance of each issue in contributing to the extra quality assurance conferred by proof testing components is discussed, particularly with respect to the application of advanced fracture mechanics concepts to enhance the flaw screening capability of a proof test analysis. Items covered include the role in proof testing of elastic-plastic fracture mechanics, ductile instability analysis, deterministic versus probabilistic analysis, single versus multiple cycle proof testing, and non-destructive examination (NDE). The effects of proof testing on subsequent service life are reviewed, particularly with regard to stress redistribution and changes in fracture behavior resulting from the overload. The importance of proof test conditions are also addressed, covering aspects related to test temperature, simulation of service environments, test media and the application of real-time NDE. The role of each issue in a proof test methodology is assessed with respect to its ability to: promote proof test practice to a state-of-the-art; aid optimization of proof test design; and increase awareness and understanding of outstanding issues.

  6. Significant issues in proof testing: A critical appraisal

    NASA Astrophysics Data System (ADS)

    Chell, G. G.; McClung, R. C.; Russell, D. A.; Chang, K. J.; Donnelly, B.

    1994-09-01

    Issues which impact on the interpretation and quantification of proof test benefits are reviewed. The importance of each issue in contributing to the extra quality assurance conferred by proof testing components is discussed, particularly with respect to the application of advanced fracture mechanics concepts to enhance the flaw screening capability of a proof test analysis. Items covered include the role in proof testing of elastic-plastic fracture mechanics, ductile instability analysis, deterministic versus probabilistic analysis, single versus multiple cycle proof testing, and non-destructive examination (NDE). The effects of proof testing on subsequent service life are reviewed, particularly with regard to stress redistribution and changes in fracture behavior resulting from the overload. The importance of proof test conditions are also addressed, covering aspects related to test temperature, simulation of service environments, test media and the application of real-time NDE. The role of each issue in a proof test methodology is assessed with respect to its ability to: promote proof test practice to a state-of-the-art; aid optimization of proof test design; and increase awareness and understanding of outstanding issues.

  7. [Significance of genetic tests in the era of personalized medicine].

    PubMed

    Molnár, Judit Mária; Magyarósi, Szilvia; Németh, György

    2013-03-01

    Due to the rapid development in genomics, genetic markers gain importance in all areas of medicine including prevention, management and therapy of patients. As a result, medicine started to shift away from evidence based procedures to a more personalized one. However, the later one requires high quality validated genetic tests. These new tests appeared as preconceptional, preimplantational, prenatal, presymptomatic, diagnostic and direct to consumer forms. Before approval such tests must be analytically and clinically validated. Broader use of these genetic tests is dependent on their price and reimbursement schemes.

  8. Significance tests for functional data with complex dependence structure.

    PubMed

    Staicu, Ana-Maria; Lahiri, Soumen N; Carroll, Raymond J

    2015-01-01

    We propose an L(2)-norm based global testing procedure for the null hypothesis that multiple group mean functions are equal, for functional data with complex dependence structure. Specifically, we consider the setting of functional data with a multilevel structure of the form groups-clusters or subjects-units, where the unit-level profiles are spatially correlated within the cluster, and the cluster-level data are independent. Orthogonal series expansions are used to approximate the group mean functions and the test statistic is estimated using the basis coefficients. The asymptotic null distribution of the test statistic is developed, under mild regularity conditions. To our knowledge this is the first work that studies hypothesis testing, when data have such complex multilevel functional and spatial structure. Two small-sample alternatives, including a novel block bootstrap for functional data, are proposed, and their performance is examined in simulation studies. The paper concludes with an illustration of a motivating experiment.

  9. Significance tests for functional data with complex dependence structure

    PubMed Central

    Lahiri, Soumen N.; Carroll, Raymond J.

    2015-01-01

    We propose an L2-norm based global testing procedure for the null hypothesis that multiple group mean functions are equal, for functional data with complex dependence structure. Specifically, we consider the setting of functional data with a multilevel structure of the form groups–clusters or subjects–units, where the unit-level profiles are spatially correlated within the cluster, and the cluster-level data are independent. Orthogonal series expansions are used to approximate the group mean functions and the test statistic is estimated using the basis coefficients. The asymptotic null distribution of the test statistic is developed, under mild regularity conditions. To our knowledge this is the first work that studies hypothesis testing, when data have such complex multilevel functional and spatial structure. Two small-sample alternatives, including a novel block bootstrap for functional data, are proposed, and their performance is examined in simulation studies. The paper concludes with an illustration of a motivating experiment. PMID:26023253

  10. A significance test for graph-constrained estimation.

    PubMed

    Zhao, Sen; Shojaie, Ali

    2016-06-01

    Graph-constrained estimation methods encourage similarities among neighboring covariates presented as nodes of a graph, and can result in more accurate estimates, especially in high-dimensional settings. Variable selection approaches can then be utilized to select a subset of variables that are associated with the response. However, existing procedures do not provide measures of uncertainty of estimates. Further, the vast majority of existing approaches assume that available graph accurately captures the association among covariates; violations to this assumption could severely hurt the reliability of the resulting estimates. In this article, we present a new inference framework, called the Grace test, which produces coefficient estimates and corresponding p-values by incorporating the external graph information. We show, both theoretically and via numerical studies, that the proposed method asymptotically controls the type-I error rate regardless of the choice of the graph. We also show that when the underlying graph is informative, the Grace test is asymptotically more powerful than similar tests that ignore the external information. We study the power properties of the proposed test when the graph is not fully informative and develop a more powerful Grace-ridge test for such settings. Our numerical studies show that as long as the graph is reasonably informative, the proposed inference procedures deliver improved statistical power over existing methods that ignore external information.

  11. Conducting tests for statistically significant differences using forest inventory data

    Treesearch

    James A. Westfall; Scott A. Pugh; John W. Coulston

    2013-01-01

    Many forest inventory and monitoring programs are based on a sample of ground plots from which estimates of forest resources are derived. In addition to evaluating metrics such as number of trees or amount of cubic wood volume, it is often desirable to make comparisons between resource attributes. To properly conduct statistical tests for differences, it is imperative...

  12. Interpretation of Statistical Significance Testing: A Matter of Perspective.

    ERIC Educational Resources Information Center

    McClure, John; Suen, Hoi K.

    1994-01-01

    This article compares three models that have been the foundation for approaches to the analysis of statistical significance in early childhood research--the Fisherian and the Neyman-Pearson models (both considered "classical" approaches), and the Bayesian model. The article concludes that all three models have a place in the analysis of research…

  13. [Prognostic significance of bicycle ergometry test in patients with myocarditis].

    PubMed

    Gavalova, R F; Borodina, V I

    1992-04-01

    A total of 42 patients with rheumatic carditis were examined in the acute-subacute period and following 3-5 years. Seventeen patients were diagnosed as having primary rheumatic carditis, 9 presented with tonsillogenic rheumatic carditis, and 16 had viral rheumatic carditis. The diagnosis of myocarditis was established on the basis of clinical, immunological, and virological findings. The study involved ECG, PhCG, PCG, and bicycle ergometer testing recordings. Groups of patients with good and poor prognosis were identified. Low threshold exercise, exercise-inadequate tachycardia, complex cardiac arrhythmias, phasic myocardial hypodynamic syndrome and volume exercise syndrome that are formed during performance are prognostically poor indicators. More profound electric and mechanic dysfunctions were observed in patients with tonsillogenic or viral myocarditis.

  14. Clinical significance of SNAP somnography test acoustic recording.

    PubMed

    Galer, Chad; Yonkers, Anthony; Duff, Wallace; Heywood, Barbara

    2007-02-01

    To examine the clinical significance of acoustic data recorded by the SNAP home polysomnography system (SNAP Laboratories, Glenview, IL). Retrospective analysis of SNAP data from 59 patients undergoing evaluation for sleep apnea at the University of Nebraska Medical Center and an associated private practice in Omaha, NE. Snoring did not correlate with anthropometric variables such as body mass index and neck circumference. Statistical analysis showed no correlation between respiratory disturbance index and the maximum or average loudness of snoring. Average loudness was predictive of the presence of sleep apnea. Spectral analysis of snoring sonography found that the proportion of snoring events associated with a palatal source correlated strongly with the loudness of snoring. These data suggest that analysis of snoring has limited utility in the evaluation of the patient with sleep apnea but may be able to select patients who would benefit from palatal procedures to reduce snoring.

  15. Testing Mediation in Structural Equation Modeling: The Effectiveness of the Test of Joint Significance

    ERIC Educational Resources Information Center

    Leth-Steensen, Craig; Gallitto, Elena

    2016-01-01

    A large number of approaches have been proposed for estimating and testing the significance of indirect effects in mediation models. In this study, four sets of Monte Carlo simulations involving full latent variable structural equation models were run in order to contrast the effectiveness of the currently popular bias-corrected bootstrapping…

  16. Testing Mediation in Structural Equation Modeling: The Effectiveness of the Test of Joint Significance

    ERIC Educational Resources Information Center

    Leth-Steensen, Craig; Gallitto, Elena

    2016-01-01

    A large number of approaches have been proposed for estimating and testing the significance of indirect effects in mediation models. In this study, four sets of Monte Carlo simulations involving full latent variable structural equation models were run in order to contrast the effectiveness of the currently popular bias-corrected bootstrapping…

  17. Review of null hypothesis significance testing in the ophthalmic literature: are most 'significant' P values false positives?

    PubMed

    Sanfilippo, Paul G; Casson, Robert J; Yazar, Seyhan; Mackey, David A; Hewitt, Alex W

    2016-01-01

    P values associated with null hypothesis significance testing (NHST) are almost universal in the ophthalmic literature. A P value < 0.05 is traditionally considered 'significant'. This concept may deflect further thought about the veracity of the results. P values influence the publishability of the data and have flow-on effects for funding success and the direction of future research. Despite their importance, the problems inherent in P values have been recognized since their inception, and in more recent years have been increasingly highlighted in some scientific fields. In this review, we aim to bring the problems associated with P values and NHST to the attention of the ophthalmic research community. We do not offer a universal solution to the problem of determining the veracity of a scientific claim; however, we demonstrate the need for caution in interpreting 'significant' P values by performing a Bayesian re-analysis of t-tests in the ophthalmic literature.

  18. Providing the Nation a Significant "High-Test Peroxide" Propulsion Test Capability

    NASA Technical Reports Server (NTRS)

    Bruce, R.; Taylor, G.; Beckmeyer, D.; Warren, S.; Dracon, S.; Powell, B.; Goodwin, D.; Rieder, P.; Nichols, R.

    1999-01-01

    Renewed interest in high-test peroxide, as a propellant, required the development of a facility capable of testing rocket propulsion systems. The development of this capability at the NASA Stennis Space Center (SSC), MS, focused on meeting this requirement. The challenges, accomplishments, and lessons learned associated with developing the SSC E3 Test Facility's high-test peroxide capability are presented herein.

  19. An Empirical Comparison of Two Methods for Testing the Significance of a Correlation Matrix.

    ERIC Educational Resources Information Center

    Wilson, Gale A.; Martin, Samuel A.

    1983-01-01

    Either Bartlett's chi-square test of sphericity or Steiger's chi-square test can be used to test the significance of a correlation matrix to determine the appropriateness of factor analysis. They were evaluated using computer-generated correlation matrices. Steiger's test is recommended due to its increased power and computational simplicity.…

  20. Patterns of Statewide Test Participation for Students with Significant Cognitive Disabilities

    ERIC Educational Resources Information Center

    Saven, Jessica L.; Anderson, Daniel; Nese, Joseph F. T.; Farley, Dan; Tindal, Gerald

    2016-01-01

    Students with significant cognitive disabilities are eligible to participate in two statewide testing options for accountability: alternate assessments or general assessments with appropriate accommodations. Participation guidelines are generally quite vague, leading to students "switching" test participation between years. In this…

  1. Understanding the Sampling Distribution and Its Use in Testing Statistical Significance.

    ERIC Educational Resources Information Center

    Breunig, Nancy A.

    Despite the increasing criticism of statistical significance testing by researchers, particularly in the publication of the 1994 American Psychological Association's style manual, statistical significance test results are still popular in journal articles. For this reason, it remains important to understand the logic of inferential statistics. A…

  2. A Review of Post-1994 Literature on Whether Statistical Significance Tests Should Be Banned.

    ERIC Educational Resources Information Center

    Sullivan, Jeremy R.

    This paper summarizes the literature regarding statistical significance testing with an emphasis on: (1) the post-1994 literature in various disciplines; (2) alternatives to statistical significance testing; and (3) literature exploring why researchers have demonstrably failed to be influenced by the 1994 American Psychological Association…

  3. "What If" Analyses: Ways to Interpret Statistical Significance Test Results Using EXCEL or "R"

    ERIC Educational Resources Information Center

    Ozturk, Elif

    2012-01-01

    The present paper aims to review two motivations to conduct "what if" analyses using Excel and "R" to understand the statistical significance tests through the sample size context. "What if" analyses can be used to teach students what statistical significance tests really do and in applied research either prospectively to estimate what sample size…

  4. Statistical Significance Testing in Second Language Research: Basic Problems and Suggestions for Reform

    ERIC Educational Resources Information Center

    Norris, John M.

    2015-01-01

    Traditions of statistical significance testing in second language (L2) quantitative research are strongly entrenched in how researchers design studies, select analyses, and interpret results. However, statistical significance tests using "p" values are commonly misinterpreted by researchers, reviewers, readers, and others, leading to…

  5. Statistical Significance Testing in Second Language Research: Basic Problems and Suggestions for Reform

    ERIC Educational Resources Information Center

    Norris, John M.

    2015-01-01

    Traditions of statistical significance testing in second language (L2) quantitative research are strongly entrenched in how researchers design studies, select analyses, and interpret results. However, statistical significance tests using "p" values are commonly misinterpreted by researchers, reviewers, readers, and others, leading to…

  6. The Historical Growth of Statistical Significance Testing in Psychology--and Its Future Prospects.

    ERIC Educational Resources Information Center

    Hubbard, Raymond; Ryan, Patricia A.

    2000-01-01

    Examined the historical growth in the popularity of statistical significance testing using a random sample of data from 12 American Psychological Association journals. Results replicate and extend findings from a study that used only one such journal. Discusses the role of statistical significance testing and the use of replication and…

  7. The clinical significance of a positive Amnisure test in women with preterm labor and intact membranes.

    PubMed

    Lee, Seung Mi; Romero, Roberto; Park, Jeong Woo; Kim, Sun Min; Park, Chan-Wook; Korzeniewski, Steven J; Chaiworapongsa, Tinnakorn; Yoon, Bo Hyun

    2012-09-01

    This study was conducted to examine the frequency and clinical significance of a positive Amnisure test in patients with preterm labor and intact membranes by sterile speculum exam. A retrospective cohort study was performed including 90 patients with preterm labor and intact membranes who underwent Amnisure tests prior to amniocentesis (< 72 h); most patients (n=64) also underwent fetal fibronectin (fFN) tests. Amniotic fluid (AF) was cultured for aerobic/anaerobic bacteria and genital mycoplasmas and assayed for matrix metalloproteinase-8. (1) the prevalence of a positive Amnisure test was 19% (17/90); (2) patients with a positive Amnisure test had significantly higher rates of adverse pregnancy and neonatal outcomes (e.g., impending preterm delivery, intra-amniotic infection/inflammation, and neonatal morbidity) than those with a negative Amnisure test; (3) a positive test was associated with significantly increased risk of intra-amniotic infection and/or inflammation, delivery within 7, 14, or 28 days and spontaneous preterm birth (< 35 weeks) among patients with a negative fFN test. A positive Amnisure test in patients with preterm labor and intact membranes is a risk factor for adverse pregnancy outcome, particularly in patients with a negative fFN test. A positive Amnisure test in patients without symptoms or signs of ROM should not be taken as an indicator that membranes have ruptured.

  8. Tests of English Language as Significant Thresholds for College-Bound Chinese and the Washback of Test-Preparation

    ERIC Educational Resources Information Center

    Matoush, Marylou M.; Fu, Danling

    2012-01-01

    Tests of English language mark significantly high thresholds for all college-bound students in the People's Republic of China. Many Chinese students hope to seek their fortunes at universities in the United States, or other English speaking countries. These students spend long hours, year after year, in test-preparation centres in order to develop…

  9. The Use (and Misuse) of Statistical Significance Testing: Some Recommendations for Improved Editorial Policy and Practice.

    ERIC Educational Resources Information Center

    Thompson, Bruce

    This paper evaluates the logic underlying various criticisms of statistical significance testing and makes specific recommendations for scientific and editorial practice that might better increase the knowledge base. Reliance on the traditional hypothesis testing model has led to a major bias against nonsignificant results and to misinterpretation…

  10. The gel test: investigation into the aetiology and the significance of a positive auto-control.

    PubMed

    Eichler, H; Kretschmer, V

    1995-08-01

    Shortly after the gel test was introduced into routine immunohaematology, an increased percentage of patients were reported to show a positive auto-control in the indirect antiglobulin test (IAT) of uncertain significance as the direct antiglobulin test (DAT) in the tube technique was negative. In our study 13,280 randomized patient blood samples were screened and additional investigations carried out including an analysis of patient histories in the 97 blood samples that were auto-control positive in the gel test. In 87.4%, a re-testing with polyspecific antiglobulin serum (83.2% with anti-IgG) showed positive results in contrast to only 52.9% re-tested by the tube test. Neither nonspecificity nor cold agglutinins were significant. None of the patients examined showed any signs of haemolysis except for one with pernicious anaemia. We concluded that the increased number of positive auto-controls and DATs is due to the greater sensitivity of the gel test and thus the detection of minute quantities of specific cell-bound IgG molecules, i.e. warm auto-antibodies or drug-induced antibodies. Prior to transfusion, a positive result should be confirmed by a tube DAT. If this test is negative and there is no history of a previous transfusion or of haemolysis, the transfusion should not be delayed by carrying out further time-consuming investigations.

  11. [Tests of statistical significance in three biomedical journals: a critical review].

    PubMed

    Sarria Castro, Madelaine; Silva Ayçaguer, Luis Carlos

    2004-05-01

    To describe the use of conventional tests of statistical significance and the current trends shown by their use in three biomedical journals read in Spanish-speaking countries. All descriptive or explanatory original articles published in the five-year period of 1996 through 2000 were reviewed in three journals: Revista Cubana de Medicina General Integral [Cuban Journal of Comprehensive General Medicine], Revista Panamericana de Salud Pública/Pan American Journal of Public Health, and Medicina Clínica [Clinical Medicine] (which is published in Spain). In the three journals that were reviewed various shortcomings were found in their use of hypothesis tests based on P values and in the limited use of new tools that have been suggested for use in their place: confidence intervals (CIs) and Bayesian inference. The basic findings of our research were: minimal use of CIs, as either a complement to significance tests or as the only statistical tool; mentions of a small sample size as a possible explanation for the lack of statistical significance; a predominant use of rigid alpha values; a lack of uniformity in the presentation of results; and improper reference in the research conclusions to the results of hypothesis tests. Our results indicate the lack of compliance by authors and editors with accepted standards for the use of tests of statistical significance. The findings also highlight that the stagnant use of these tests continues to be a common practice in the scientific literature.

  12. [Significance of various oxytocin challenge tests in monitoring pregnant women at risk (author's transl)].

    PubMed

    Bichler, A; Dorfmann, A

    1975-08-01

    Three different oxytocin challenge tests were used for the anssessment of placentar function in pregnant women at risk: For the oxytocin test after Ray et al. Oxytocin was given in continuity with rising doses. In the two other tests Oxytocin was given intermittently with identical doses. The test described by Ray et al. Proved useful for predicting respiratory insufficiency of the placenta. The two other intermittent tests are, according to our investigations, less suitable as tests of placentar function because their significance is limited or non-existent. The continuous oxytocin challenge test takes more time (one hour on average). Essential for exact interpretation are a careful technique and surveillance of the patient throughout the test by trained personel. In our opinion the indications for the continous oxytocin challenge test are pregnancies at risk, where antepartum cardniotocography shows suspect or hard-to-interprete results (e.g. non-classifiables decelerations, loss of fluctuation, absence of Braxton-Hicks contractions) or when other monitoring techniques indicate placentar insufficiency (e.g. low oestriol excretion). The test is not suitable in placenta previaprevia, threatened premature birth and premature ruptur of the membranes. In contrast to other authors we cannot decide with certainly whether patients with a positive oxytocin challenge test should in every case be treated with Caesarean section [9]. This decision will depend not only on the result of the test but on the assessment of all parameters, mainly on the clinical picture. In any case delivery of patients with positive oxytocin challenge tests will have to be carried out under strict technical and biochemical supervision.

  13. Use of power analysis to develop detectable significance criteria for sea urchin toxicity tests

    USGS Publications Warehouse

    Carr, R.S.; Biedenbach, J.M.

    1999-01-01

    When sufficient data are available, the statistical power of a test can be determined using power analysis procedures. The term “detectable significance” has been coined to refer to this criterion based on power analysis and past performance of a test. This power analysis procedure has been performed with sea urchin (Arbacia punctulata) fertilization and embryological development data from sediment porewater toxicity tests. Data from 3100 and 2295 tests for the fertilization and embryological development tests, respectively, were used to calculate the criteria and regression equations describing the power curves. Using Dunnett's test, a minimum significant difference (MSD) (β = 0.05) of 15.5% and 19% for the fertilization test, and 16.4% and 20.6% for the embryological development test, for α ≤ 0.05 and α ≤ 0.01, respectively, were determined. The use of this second criterion reduces type I (false positive) errors and helps to establish a critical level of difference based on the past performance of the test.

  14. RV-coefficient and its significance test in mapping brain functional connectivity

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Tian, Jie; Li, Jun; Zhao, Jizheng

    2009-02-01

    The statistic of RV-coefficient is a good substitute for the Pearson correlation coefficient to measure the temporal similarity of two local brain regions. However, the hypothesis test of RV-coefficient is a hard problem which limits its application. This paper discussed the problem in details. Since the distribution of RV-coefficient is unknown, we do not know a critical p-value to statistically test its significance. We proposed a new strategy to test the significance of RV calculated from fMRI. In order to approximate the p-value, we elicited the first two moments of the population permutation distribution of RV; we then derived a formula to more closely approximate the normal distribution with these transformed statistics. These transformations of statistics are suggested for a precise approximation to the permutational p-value even under large number of observations. This strategy of test can greatly reduce the computational complexity and avoid "calculation catastrophe", we then use the statistic of RV to extract the map of functional connectivity from fMRI and test its significance with the strategy proposed here.

  15. Uses and Abuses of Statistical Significance Tests and Other Statistical Resources: A Comparative Study

    ERIC Educational Resources Information Center

    Monterde-i-Bort, Hector; Frias-Navarro, Dolores; Pascual-Llobell, Juan

    2010-01-01

    The empirical study we present here deals with a pedagogical issue that has not been thoroughly explored up until now in our field. Previous empirical studies in other sectors have identified the opinions of researchers about this topic, showing that completely unacceptable interpretations have been made of significance tests and other statistical…

  16. Interpreting Statistical Significance Test Results: A Proposed New "What If" Method.

    ERIC Educational Resources Information Center

    Kieffer, Kevin M.; Thompson, Bruce

    As the 1994 publication manual of the American Psychological Association emphasized, "p" values are affected by sample size. As a result, it can be helpful to interpret the results of statistical significant tests in a sample size context by conducting so-called "what if" analyses. However, these methods can be inaccurate…

  17. Recent Literature on Whether Statistical Significance Tests Should or Should Not Be Banned.

    ERIC Educational Resources Information Center

    Deegear, James

    This paper summarizes the literature regarding statistical significant testing with an emphasis on recent literature in various discipline and literature exploring why researchers have demonstrably failed to be influenced by the American Psychological Association publication manual's encouragement to report effect sizes. Also considered are…

  18. Measured dose to ovaries and testes from Hodgkin's fields and determination of genetically significant dose

    SciTech Connect

    Niroomand-Rad, A.; Cumberlin, R. )

    1993-03-15

    The purpose of this study was to determine the genetically significant dose from therapeutic radiation exposure with Hodgkin's fields by estimating the doses to ovaries and testes. Phantom measurements were performed to verify estimated doses to ovaries and testes from Hodgkin's fields. Thermoluminescent LiF dosimeters (TLD-100) of 1 x 3 x 3 mm[sup 3] dimensions were embedded in phantoms and exposed to standard mantle and paraaortic fields using Co-60, 4 MV, 6 MV, and 10 MV photon beams. The results show that measured doses to ovaries and testes are about two to five times higher than the corresponding graphically estimated doses for Co-60 and 4 MVX photon beams as depicted in ICRP publication 44. In addition, the measured doses to ovaries and testes are about 30% to 65% lower for 10 MV photon beams than for their corresponding Co-60 photon beams. The genetically significant dose from Hodgkin's treatment (less than 0.01 mSv) adds about 4% to the genetically significant dose contribution to medical procedures and adds less than 1% to the genetically significant dose from all sources. Therefore, the consequence to society is considered to be very small. The consequences for the individual patient are, likewise, small. 28 refs., 3 figs., 5 tabs.

  19. Alphas and Asterisks: The Development of Statistical Significance Testing Standards in Sociology

    ERIC Educational Resources Information Center

    Leahey, Erin

    2005-01-01

    In this paper, I trace the development of statistical significance testing standards in sociology by analyzing data from articles published in two prestigious sociology journals between 1935 and 2000. I focus on the role of two key elements in the diffusion literature, contagion and rationality, as well as the role of institutional factors. I…

  20. Thou Shalt Not Bear False Witness against Null Hypothesis Significance Testing

    ERIC Educational Resources Information Center

    García-Pérez, Miguel A.

    2017-01-01

    Null hypothesis significance testing (NHST) has been the subject of debate for decades and alternative approaches to data analysis have been proposed. This article addresses this debate from the perspective of scientific inquiry and inference. Inference is an inverse problem and application of statistical methods cannot reveal whether effects…

  1. A National Survey of AERA Members' Perceptions of Statistical Significance Tests and Other Statistical Issues.

    ERIC Educational Resources Information Center

    Mittag, Kathleen C.; Thompson, Bruce

    2000-01-01

    Surveyed AERA members regarding their perceptions of: statistical issues and statistical significance testing; the general linear model; stepwise methods; score reliability; type I and II errors; sample size; statistical probabilities as exclusive measures of effect size; p values as direct measures of result value; and p values evaluating…

  2. Uses and Abuses of Statistical Significance Tests and Other Statistical Resources: A Comparative Study

    ERIC Educational Resources Information Center

    Monterde-i-Bort, Hector; Frias-Navarro, Dolores; Pascual-Llobell, Juan

    2010-01-01

    The empirical study we present here deals with a pedagogical issue that has not been thoroughly explored up until now in our field. Previous empirical studies in other sectors have identified the opinions of researchers about this topic, showing that completely unacceptable interpretations have been made of significance tests and other statistical…

  3. A National Survey of AERA Members' Perceptions of the Nature and Meaning of Statistical Significance Tests.

    ERIC Educational Resources Information Center

    Mittag, Kathleen C

    A national survey of a stratified random sample of members of the American Educational Research Association was undertaken to explore perceptions of contemporary statistical issues, and especially of statistical significance tests. The 225 actual respondents were found to be reasonably representative of the population from which the sample was…

  4. Visual mining methods for RNA-Seq data: data structure, dispersion estimation and significance testing

    USDA-ARS?s Scientific Manuscript database

    In an analysis of RNA-Seq data from soybeans, initial significance testing using one software package produced very different gene lists from those yielded by another. How can this happen? This paper demonstrates how the disparities between the results were investigated, and can be explained. This t...

  5. A Communication Researchers' Guide to Null Hypothesis Significance Testing and Alternatives

    ERIC Educational Resources Information Center

    Levine, Timothy R.; Weber, Rene; Park, Hee Sun; Hullett, Craig R.

    2008-01-01

    This paper offers a practical guide to use null hypotheses significance testing and its alternatives. The focus is on improving the quality of statistical inference in quantitative communication research. More consistent reporting of descriptive statistics, estimates of effect size, confidence intervals around effect sizes, and increasing the…

  6. A Critical Assessment of Null Hypothesis Significance Testing in Quantitative Communication Research

    ERIC Educational Resources Information Center

    Levine, Timothy R.; Weber, Rene; Hullett, Craig; Park, Hee Sun; Lindsey, Lisa L. Massi

    2008-01-01

    Null hypothesis significance testing (NHST) is the most widely accepted and frequently used approach to statistical inference in quantitative communication research. NHST, however, is highly controversial, and several serious problems with the approach have been identified. This paper reviews NHST and the controversy surrounding it. Commonly…

  7. Statistical Significance Testing in "Educational and Psychological Measurement" and Other Journals.

    ERIC Educational Resources Information Center

    Daniel, Larry G.

    Statistical significance tests (SSTs) have been the object of much controversy among social scientists. Proponents have hailed SSTs as an objective means for minimizing the likelihood that chance factors have contributed to research results. Critics have both questioned the logic underlying SSTs and bemoaned the widespread misapplication and…

  8. Prognostic significance of performing universal HER2 testing in cases of advanced gastric cancer.

    PubMed

    Jiménez-Fonseca, Paula; Carmona-Bayonas, Alberto; Sánchez Lorenzo, Maria Luisa; Plazas, Javier Gallego; Custodio, Ana; Hernández, Raquel; Garrido, Marcelo; García, Teresa; Echavarría, Isabel; Cano, Juana María; Rodríguez Palomo, Alberto; Mangas, Monserrat; Macías Declara, Ismael; Ramchandani, Avinash; Visa, Laura; Viudez, Antonio; Buxó, Elvira; Díaz-Serrano, Asunción; López, Carlos; Azkarate, Aitor; Longo, Federico; Castañón, Eduardo; Sánchez Bayona, Rodrigo; Pimentel, Paola; Limón, Maria Luisa; Cerdá, Paula; Álvarez Llosa, Renata; Serrano, Raquel; Lobera, Maria Pilar Felices; Alsina, María; Hurtado Nuño, Alicia; Gómez-Martin, Carlos

    2017-05-01

    Trastuzumab significantly improves overall survival (OS) when added to cisplatin and fluoropyrimidine as a treatment for HER2-positive advanced gastric cancers (AGC). The aim of this study was to evaluate the impact of the gradual implementation of HER2 testing on patient prognosis in a national registry of AGC. This Spanish National Cancer Registry includes cases who were consecutively recruited at 28 centers from January 2008 to January 2016. The effect of missing HER2 status was assessed using stratified Cox proportional hazards (PH) regression. The rate of HER2 testing increased steadily over time, from 58.3 % in 2008 to 92.9 % in 2016. HER2 was positive in 194 tumors (21.3 %). In the stratified Cox PH regression, each 1 % increase in patients who were not tested for HER2 at the institutions was associated with an approximately 0.3 % increase in the risk of death: hazard ratio, 1.0035 (CI 95 %, 1.001-1.005), P = 0.0019. Median OS was significantly lower at institutions with the highest proportions of patients who were not tested for HER2. Patients treated at centers that took longer to implement HER2 testing exhibited worse clinical outcomes. The speed of implementation behaves as a quality-of-care indicator. Reviewed guidelines on HER2 testing should be used to achieve this goal in a timely manner.

  9. Significance tests for the wavelet power and the wavelet power spectrum

    NASA Astrophysics Data System (ADS)

    Ge, Z.

    2007-11-01

    Significance tests usually address the issue how to distinguish statistically significant results from those due to pure randomness when only one sample of the population is studied. This issue is also important when the results obtained using the wavelet analysis are to be interpreted. Torrence and Compo (1998) is one of the earliest works that has systematically discussed this problem. Their results, however, were based on Monte Carlo simulations, and hence, failed to unveil many interesting and important properties of the wavelet analysis. In the present work, the sampling distributions of the wavelet power and power spectrum of a Gaussian White Noise (GWN) were derived in a rigorous statistical framework, through which the significance tests for these two fundamental quantities in the wavelet analysis were established. It was found that the results given by Torrence and Compo (1998) are numerically accurate when adjusted by a factor of the sampling period, while some of their statements require reassessment. More importantly, the sampling distribution of the wavelet power spectrum of a GWN was found to be highly dependent on the local covariance structure of the wavelets, a fact that makes the significance levels intimately related to the specific wavelet family. In addition to simulated signals, the significance tests developed in this work were demonstrated on an actual wave elevation time series observed from a buoy on Lake Michigan. In this simple application in geophysics, we showed how proper significance tests helped to sort out physically meaningful peaks from those created by random noise. The derivations in the present work can be readily extended to other wavelet-based quantities or analyses using other wavelet families.

  10. Are all significant P values created equal? The analogy between diagnostic tests and clinical research.

    PubMed

    Browner, W S; Newman, T B

    1987-05-08

    Just as diagnostic tests are most helpful in light of the clinical presentation, statistical tests are most useful in the context of scientific knowledge. Knowing the specificity and sensitivity of a diagnostic test is necessary, but insufficient: the clinician must also estimate the prior probability of the disease. In the same way, knowing the P value and power, or the confidence interval, for the results of a research study is necessary but insufficient: the reader must estimate the prior probability that the research hypothesis is true. Just as a positive diagnostic test does not mean that a patient has the disease, especially if the clinical picture suggests otherwise, a significant P value does not mean that a research hypothesis is correct, especially if it is inconsistent with current knowledge. Powerful studies are like sensitive tests in that they can be especially useful when the results are negative. Very low P values are like very specific tests; both result in few false-positive results due to chance. This Bayesian approach can clarify much of the confusion surrounding the use and interpretation of statistical tests.

  11. A common misapplication of statistical inference: Nuisance control with null-hypothesis significance tests.

    PubMed

    Sassenhagen, Jona; Alday, Phillip M

    2016-11-01

    Experimental research on behavior and cognition frequently rests on stimulus or subject selection where not all characteristics can be fully controlled, even when attempting strict matching. For example, when contrasting patients to controls, variables such as intelligence or socioeconomic status are often correlated with patient status. Similarly, when presenting word stimuli, variables such as word frequency are often correlated with primary variables of interest. One procedure very commonly employed to control for such nuisance effects is conducting inferential tests on confounding stimulus or subject characteristics. For example, if word length is not significantly different for two stimulus sets, they are considered as matched for word length. Such a test has high error rates and is conceptually misguided. It reflects a common misunderstanding of statistical tests: interpreting significance not to refer to inference about a particular population parameter, but about 1. the sample in question, 2. the practical relevance of a sample difference (so that a nonsignificant test is taken to indicate evidence for the absence of relevant differences). We show inferential testing for assessing nuisance effects to be inappropriate both pragmatically and philosophically, present a survey showing its high prevalence, and briefly discuss an alternative in the form of regression including nuisance variables.

  12. A Non-Parametric Surrogate-based Test of Significance for T-Wave Alternans Detection

    PubMed Central

    Nemati, Shamim; Abdala, Omar; Bazán, Violeta; Yim-Yeh, Susie; Malhotra, Atul; Clifford, Gari

    2010-01-01

    We present a non-parametric adaptive surrogate test that allows for the differentiation of statistically significant T-Wave Alternans (TWA) from alternating patterns that can be solely explained by the statistics of noise. The proposed test is based on estimating the distribution of noise induced alternating patterns in a beat sequence from a set of surrogate data derived from repeated reshuffling of the original beat sequence. Thus, in assessing the significance of the observed alternating patterns in the data no assumptions are made about the underlying noise distribution. In addition, since the distribution of noise-induced alternans magnitudes is calculated separately for each sequence of beats within the analysis window, the method is robust to data non-stationarities in both noise and TWA. The proposed surrogate method for rejecting noise was compared to the standard noise rejection methods used with the Spectral Method (SM) and the Modified Moving Average (MMA) techniques. Using a previously described realistic multi-lead model of TWA, and real physiological noise, we demonstrate the proposed approach reduces false TWA detections, while maintaining a lower missed TWA detection compared with all the other methods tested. A simple averaging-based TWA estimation algorithm was coupled with the surrogate significance testing and was evaluated on three public databases; the Normal Sinus Rhythm Database (NRSDB), the Chronic Heart Failure Database (CHFDB) and the Sudden Cardiac Death Database (SCDDB). Differences in TWA amplitudes between each database were evaluated at matched heart rate (HR) intervals from 40 to 120 beats per minute (BPM). Using the two-sample Kolmogorov-Smirnov test, we found that significant differences in TWA levels exist between each patient group at all decades of heart rates. The most marked difference was generally found at higher heart rates, and the new technique resulted in a larger margin of separability between patient populations than

  13. Applications and statistical properties of minimum significant difference-based criterion testing in a toxicity testing program

    SciTech Connect

    Wang, Q.; Denton, D.L.; Shukla, R.

    2000-01-01

    As a follow up to the recommendations of the September 1995 SETAC Pellston Workshop on Whole Effluent Toxicity (WET) on test methods and appropriate endpoints, this paper will discuss the applications and statistical properties of using a statistical criterion of minimum significant difference (MSD). The authors examined the upper limits of acceptable MSDs as acceptance criterion in the case of normally distributed data. The implications of this approach are examined in terms of false negative rate as well as false positive rate. Results indicated that the proposed approach has reasonable statistical properties. Reproductive data from short-term chronic WET test with Ceriodaphnia dubia tests were used to demonstrate the applications of the proposed approach. The data were collected by the North Carolina Department of Environment, Health, and Natural Resources (Raleigh, NC, USA) as part of their National Pollutant Discharge Elimination System program.

  14. Significance of hydrogen breath tests in children with suspected carbohydrate malabsorption.

    PubMed

    Däbritz, Jan; Mühlbauer, Michael; Domagk, Dirk; Voos, Nicole; Henneböhl, Geraldine; Siemer, Maria L; Foell, Dirk

    2014-02-27

    Hydrogen breath tests are noninvasive procedures frequently applied in the diagnostic workup of functional gastrointestinal disorders. Here, we review hydrogen breath test results and the occurrence of lactose, fructose and sorbitol malabsorption in pediatric patients; and determine the significance of the findings and the outcome of patients with carbohydrate malabsorption. We included 206 children (88 male, 118 female, median age 10.7 years, range 3-18 years) with a total of 449 hydrogen breath tests (lactose, n = 161; fructose, n = 142; sorbitol, n = 146) into a retrospective analysis. Apart from test results, we documented symptoms, the therapeutic consequences of the test, the outcome and the overall satisfaction of the patients and families. In total, 204 (46%) of all breath tests were positive. Long-term follow-up data could be collected from 118 patients. Of 79 patients (67%) who were put on a diet reduced in lactose, fructose and/or sorbitol, the majority (92%, n = 73) reported the diet to be strict and only 13% (n = 10) had no response to diet. Most families (96%, n = 113) were satisfied by the test and the therapy. There were only 21 tests (5%) with a borderline result because the criteria for a positive result were only partially met. Hydrogen breath tests can be helpful in the evaluation of children with gastrointestinal symptoms including functional intestinal disorders. If applied for a variety of carbohydrates but only where indicated, around two-third of all children have positive results. The therapeutic consequences are successfully relieving symptoms in the vast majority of patients.

  15. Significance of hydrogen breath tests in children with suspected carbohydrate malabsorption

    PubMed Central

    2014-01-01

    Background Hydrogen breath tests are noninvasive procedures frequently applied in the diagnostic workup of functional gastrointestinal disorders. Here, we review hydrogen breath test results and the occurrence of lactose, fructose and sorbitol malabsorption in pediatric patients; and determine the significance of the findings and the outcome of patients with carbohydrate malabsorption. Methods We included 206 children (88 male, 118 female, median age 10.7 years, range 3–18 years) with a total of 449 hydrogen breath tests (lactose, n = 161; fructose, n = 142; sorbitol, n = 146) into a retrospective analysis. Apart from test results, we documented symptoms, the therapeutic consequences of the test, the outcome and the overall satisfaction of the patients and families. Results In total, 204 (46%) of all breath tests were positive. Long-term follow-up data could be collected from 118 patients. Of 79 patients (67%) who were put on a diet reduced in lactose, fructose and/or sorbitol, the majority (92%, n = 73) reported the diet to be strict and only 13% (n = 10) had no response to diet. Most families (96%, n = 113) were satisfied by the test and the therapy. There were only 21 tests (5%) with a borderline result because the criteria for a positive result were only partially met. Conclusions Hydrogen breath tests can be helpful in the evaluation of children with gastrointestinal symptoms including functional intestinal disorders. If applied for a variety of carbohydrates but only where indicated, around two-third of all children have positive results. The therapeutic consequences are successfully relieving symptoms in the vast majority of patients. PMID:24575947

  16. The Significance of Early Time Data in Interference Testing for Linear Boundary Dectection

    SciTech Connect

    Sageev, Abraham; Leaver, Jonathan D.; Ramey, Henry J. Jr.

    1986-01-21

    This paper considers the significance of early time data for detecting linear boundaries using interference testing. When the ratio r{sub 2}/r{sub 1} is greater than 5, existing methods of analysis may be used. For ratios of r{sub 2}/r{sub 1} smaller than 5, special considerations are needed. When the ratio of r{sub 2}/r{sub 1} is smaller than 2, there is no significant indication of the presence of a linear boundary in the pressure response. The effects of missing pressure data during the early time flow period, and earth tides on the linear boundary analysis are described and demonstrated with a flow test in the Ohaaki geothermal field in New Zealand.

  17. Microsatellite allele sizes: a simple test to assess their significance on genetic differentiation.

    PubMed Central

    Hardy, Olivier J; Charbonnel, Nathalie; Fréville, Hélène; Heuertz, Myriam

    2003-01-01

    The mutation process at microsatellite loci typically occurs at high rates and with stepwise changes in allele sizes, features that may introduce bias when using classical measures of population differentiation based on allele identity (e.g., F(ST), Nei's Ds genetic distance). Allele size-based measures of differentiation, assuming a stepwise mutation process [e.g., Slatkin's R(ST), Goldstein et al.'s (deltamu)(2)], may better reflect differentiation at microsatellite loci, but they suffer high sampling variance. The relative efficiency of allele size- vs. allele identity-based statistics depends on the relative contributions of mutations vs. drift to population differentiation. We present a simple test based on a randomization procedure of allele sizes to determine whether stepwise-like mutations contributed to genetic differentiation. This test can be applied to any microsatellite data set designed to assess population differentiation and can be interpreted as testing whether F(ST) = R(ST). Computer simulations show that the test efficiently identifies which of F(ST) or R(ST) estimates has the lowest mean square error. A significant test, implying that R(ST) performs better than F(ST), is obtained when the mutation rate, mu, for a stepwise mutation process is (a) >/= m in an island model (m being the migration rate among populations) or (b) >/= 1/t in the case of isolated populations (t being the number of generations since population divergence). The test also informs on the efficiency of other statistics used in phylogenetical reconstruction [e.g., Ds and (deltamu)(2)], a nonsignificant test meaning that allele identity-based statistics perform better than allele size-based ones. This test can also provide insights into the evolutionary history of populations, revealing, for example, phylogeographic patterns, as illustrated by applying it on three published data sets. PMID:12702690

  18. Setting an Optimal α That Minimizes Errors in Null Hypothesis Significance Tests

    PubMed Central

    Mudge, Joseph F.; Baker, Leanne F.; Edge, Christopher B.; Houlahan, Jeff E.

    2012-01-01

    Null hypothesis significance testing has been under attack in recent years, partly owing to the arbitrary nature of setting α (the decision-making threshold and probability of Type I error) at a constant value, usually 0.05. If the goal of null hypothesis testing is to present conclusions in which we have the highest possible confidence, then the only logical decision-making threshold is the value that minimizes the probability (or occasionally, cost) of making errors. Setting α to minimize the combination of Type I and Type II error at a critical effect size can easily be accomplished for traditional statistical tests by calculating the α associated with the minimum average of α and β at the critical effect size. This technique also has the flexibility to incorporate prior probabilities of null and alternate hypotheses and/or relative costs of Type I and Type II errors, if known. Using an optimal α results in stronger scientific inferences because it estimates and minimizes both Type I errors and relevant Type II errors for a test. It also results in greater transparency concerning assumptions about relevant effect size(s) and the relative costs of Type I and II errors. By contrast, the use of α = 0.05 results in arbitrary decisions about what effect sizes will likely be considered significant, if real, and results in arbitrary amounts of Type II error for meaningful potential effect sizes. We cannot identify a rationale for continuing to arbitrarily use α = 0.05 for null hypothesis significance tests in any field, when it is possible to determine an optimal α. PMID:22389720

  19. When Null Hypothesis Significance Testing Is Unsuitable for Research: A Reassessment

    PubMed Central

    Szucs, Denes; Ioannidis, John P. A.

    2017-01-01

    Null hypothesis significance testing (NHST) has several shortcomings that are likely contributing factors behind the widely debated replication crisis of (cognitive) neuroscience, psychology, and biomedical science in general. We review these shortcomings and suggest that, after sustained negative experience, NHST should no longer be the default, dominant statistical practice of all biomedical and psychological research. If theoretical predictions are weak we should not rely on all or nothing hypothesis tests. Different inferential methods may be most suitable for different types of research questions. Whenever researchers use NHST they should justify its use, and publish pre-study power calculations and effect sizes, including negative findings. Hypothesis-testing studies should be pre-registered and optimally raw data published. The current statistics lite educational approach for students that has sustained the widespread, spurious use of NHST should be phased out. PMID:28824397

  20. Using the Bootstrap Method for a Statistical Significance Test of Differences between Summary Histograms

    NASA Technical Reports Server (NTRS)

    Xu, Kuan-Man

    2006-01-01

    A new method is proposed to compare statistical differences between summary histograms, which are the histograms summed over a large ensemble of individual histograms. It consists of choosing a distance statistic for measuring the difference between summary histograms and using a bootstrap procedure to calculate the statistical significance level. Bootstrapping is an approach to statistical inference that makes few assumptions about the underlying probability distribution that describes the data. Three distance statistics are compared in this study. They are the Euclidean distance, the Jeffries-Matusita distance and the Kuiper distance. The data used in testing the bootstrap method are satellite measurements of cloud systems called cloud objects. Each cloud object is defined as a contiguous region/patch composed of individual footprints or fields of view. A histogram of measured values over footprints is generated for each parameter of each cloud object and then summary histograms are accumulated over all individual histograms in a given cloud-object size category. The results of statistical hypothesis tests using all three distances as test statistics are generally similar, indicating the validity of the proposed method. The Euclidean distance is determined to be most suitable after comparing the statistical tests of several parameters with distinct probability distributions among three cloud-object size categories. Impacts on the statistical significance levels resulting from differences in the total lengths of satellite footprint data between two size categories are also discussed.

  1. Significance tests for the wavelet cross spectrum and wavelet linear coherence

    NASA Astrophysics Data System (ADS)

    Ge, Z.

    2008-12-01

    This work attempts to develop significance tests for the wavelet cross spectrum and the wavelet linear coherence as a follow-up study on Ge (2007). Conventional approaches that are used by Torrence and Compo (1998) based on stationary background noise time series were used here in estimating the sampling distributions of the wavelet cross spectrum and the wavelet linear coherence. The sampling distributions are then used for establishing significance levels for these two wavelet-based quantities. In addition to these two wavelet quantities, properties of the phase angle of the wavelet cross spectrum of, or the phase difference between, two Gaussian white noise series are discussed. It is found that the tangent of the principal part of the phase angle approximately has a standard Cauchy distribution and the phase angle is uniformly distributed, which makes it impossible to establish significance levels for the phase angle. The simulated signals clearly show that, when there is no linear relation between the two analysed signals, the phase angle disperses into the entire range of [-π,π] with fairly high probabilities for values close to ±π to occur. Conversely, when linear relations are present, the phase angle of the wavelet cross spectrum settles around an associated value with considerably reduced fluctuations. When two signals are linearly coupled, their wavelet linear coherence will attain values close to one. The significance test of the wavelet linear coherence can therefore be used to complement the inspection of the phase angle of the wavelet cross spectrum. The developed significance tests are also applied to actual data sets, simultaneously recorded wind speed and wave elevation series measured from a NOAA buoy on Lake Michigan. Significance levels of the wavelet cross spectrum and the wavelet linear coherence between the winds and the waves reasonably separated meaningful peaks from those generated by randomness in the data set. As with simulated

  2. Prevention of significant deterioration application for approval to construct SP-100 Ground Engineering System Test Site

    NASA Astrophysics Data System (ADS)

    1990-04-01

    The following application is being submitted by the U.S. Department of Energy, Richland Operations Office, P.O. Box 550, Richland, Washington 99352, pursuant to WAC 173-403-080, and in compliance with the Department of Ecology Guide to Processin g a Prevention of Significant Deterioration (PSD) Permit for a new source of airborne radionuclide emissions at the Hanford Site in Washington State. The new source, the SP-100 Ground Engineering System (GES) Test Site, will be located in the 309 Building of the 300 Area. The U.S. Department of Energy (DOE), the National Aeronautics and Space Administration (NASA), and the U.S. Department of Defense (DOD) have entered into an agreement to jointly develop space nuclear reactor power system technology. The DOE has primary responsibility for developing and ground testing the nuclear subsystem. A ground test of a reactor is necessary to demonstrate technology readiness of this major subsystem before proceeding with the flight system development and demonstration. The SP-100 GES Test Site will provide a location for the operation and testing of a prototype space-based, liquid metal-cooled, fast flux nuclear reactor in an environment closely simulating the vacuum and temperature conditions of space operations. The purpose of the GES is to develop safe, compact, light-weight and durable space reactor power system technology.

  3. From statistical non-significance to statistical equivalence: An alternative approach for whole effluent toxicity testing

    SciTech Connect

    Shukla, R.; Yu Daohai; Fulk, F.

    1995-12-31

    Short-term toxicity tests with aquatic organisms are a valuable measurement tool in the assessment of the toxicity of effluents, environmental samples and single chemicals. Currently toxicity tests are utilized in a wide range of US EPA regulatory activities including effluent discharge compliance. In the current approach for determining the No Observed Effect Concentration, an effluent concentration is presumed safe if there is no statistically significant difference in toxicant response versus control response. The conclusion of a safe concentration may be due to the fact that it truly is safe, or alternatively, that the ability of the statistical test to detect an effect, given its existence, is inadequate. Results of research of a new statistical approach, the basis of which is to move away from a demonstration of no difference to a demonstration of equivalence, will be discussed. The concept of observed confidence distributions, first suggested by Cox, is proposed as a measure of the strength of evidence for practically equivalent responses between a given effluent concentration and the control. The research included determination of intervals of practically equivalent responses as a function of the variability of control response. The approach is illustrated using reproductive data from tests with Ceriodaphnia dubia and survival and growth data from tests with fathead minnow. The data are from the US EPA`s National Reference Toxicant Database.

  4. Significance of Landsat-7 Spacecraft Level Thermal Balance and Thermal Test for ETM+Instrument

    NASA Technical Reports Server (NTRS)

    Choi, Michael K.

    1999-01-01

    The thermal design and the instrument thermal vacuum (T/V) test of the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) instrument were based on the Landsat-4, 5 and 6 heritage. The ETM+ scanner thermal model was also inherited from Landsat-4, 5 and 6. The temperature predictions of many scanner components in the original thermal model had poor agreement with the spacecraft and instrument integrated sun-pointing safehold (SPSH) thermal balance (T/B) test results. The spacecraft and instrument integrated T/B test led to a change of the Full Aperture Calibrator (FAC) motor stack "solar shield" coating from MIL-C-5541 to multi-layer insulation (MLI) thermal blanket. The temperature predictions of the Auxiliary Electronics Module (AEM) in the thermal model also had poor agreement with the T/B test results. Modifications to the scanner and AEM thermal models were performed to give good agreement between the temperature predictions and the test results. The correlated ETM+ thermal model was used to obtain flight temperature predictions. The flight temperature predictions in the nominal 15-orbit mission profile, plus margins, were used as the yellow limits for most of the ETM+ components. The spacecraft and instrument integrated T/B and TN test also revealed that the standby heater capacity on the Scan Mirror Assembly (SMA) was insufficient when the Earth Background Simulator (EBS) was 1 50C or colder, and the baffle heater possibly caused the coherent noise in the narrow band data when it was on. Also, the cooler cool-down was significantly faster than that in the instrument T/V test, and the coldest Cold Focal Plane Array (CFPA) temperature achieved was colder.

  5. Confidence Intervals Permit, but Do Not Guarantee, Better Inference than Statistical Significance Testing

    PubMed Central

    Coulson, Melissa; Healey, Michelle; Fidler, Fiona; Cumming, Geoff

    2010-01-01

    A statistically significant result, and a non-significant result may differ little, although significance status may tempt an interpretation of difference. Two studies are reported that compared interpretation of such results presented using null hypothesis significance testing (NHST), or confidence intervals (CIs). Authors of articles published in psychology, behavioral neuroscience, and medical journals were asked, via email, to interpret two fictitious studies that found similar results, one statistically significant, and the other non-significant. Responses from 330 authors varied greatly, but interpretation was generally poor, whether results were presented as CIs or using NHST. However, when interpreting CIs respondents who mentioned NHST were 60% likely to conclude, unjustifiably, the two results conflicted, whereas those who interpreted CIs without reference to NHST were 95% likely to conclude, justifiably, the two results were consistent. Findings were generally similar for all three disciplines. An email survey of academic psychologists confirmed that CIs elicit better interpretations if NHST is not invoked. Improved statistical inference can result from encouragement of meta-analytic thinking and use of CIs but, for full benefit, such highly desirable statistical reform requires also that researchers interpret CIs without recourse to NHST. PMID:21607077

  6. Confidence intervals permit, but do not guarantee, better inference than statistical significance testing.

    PubMed

    Coulson, Melissa; Healey, Michelle; Fidler, Fiona; Cumming, Geoff

    2010-01-01

    A statistically significant result, and a non-significant result may differ little, although significance status may tempt an interpretation of difference. Two studies are reported that compared interpretation of such results presented using null hypothesis significance testing (NHST), or confidence intervals (CIs). Authors of articles published in psychology, behavioral neuroscience, and medical journals were asked, via email, to interpret two fictitious studies that found similar results, one statistically significant, and the other non-significant. Responses from 330 authors varied greatly, but interpretation was generally poor, whether results were presented as CIs or using NHST. However, when interpreting CIs respondents who mentioned NHST were 60% likely to conclude, unjustifiably, the two results conflicted, whereas those who interpreted CIs without reference to NHST were 95% likely to conclude, justifiably, the two results were consistent. Findings were generally similar for all three disciplines. An email survey of academic psychologists confirmed that CIs elicit better interpretations if NHST is not invoked. Improved statistical inference can result from encouragement of meta-analytic thinking and use of CIs but, for full benefit, such highly desirable statistical reform requires also that researchers interpret CIs without recourse to NHST.

  7. Many tests of significance: new methods for controlling type I errors.

    PubMed

    Keselman, H J; Miller, Charles W; Holland, Burt

    2011-12-01

    There have been many discussions of how Type I errors should be controlled when many hypotheses are tested (e.g., all possible comparisons of means, correlations, proportions, the coefficients in hierarchical models, etc.). By and large, researchers have adopted familywise (FWER) control, though this practice certainly is not universal. Familywise control is intended to deal with the multiplicity issue of computing many tests of significance, yet such control is conservative--that is, less powerful--compared to per test/hypothesis control. The purpose of our article is to introduce the readership, particularly those readers familiar with issues related to controlling Type I errors when many tests of significance are computed, to newer methods that provide protection from the effects of multiple testing, yet are more powerful than familywise controlling methods. Specifically, we introduce a number of procedures that control the k-FWER. These methods--say, 2-FWER instead of 1-FWER (i.e., FWER)--are equivalent to specifying that the probability of 2 or more false rejections is controlled at .05, whereas FWER controls the probability of any (i.e., 1 or more) false rejections at .05. 2-FWER implicitly tolerates 1 false rejection and makes no explicit attempt to control the probability of its occurrence, unlike FWER, which tolerates no false rejections at all. More generally, k-FWER tolerates k - 1 false rejections, but controls the probability of k or more false rejections at α =.05. We demonstrate with two published data sets how more hypotheses can be rejected with k-FWER methods compared to FWER control.

  8. A novel measure and significance testing in data analysis of cell image segmentation.

    PubMed

    Wu, Jin Chu; Halter, Michael; Kacker, Raghu N; Elliott, John T; Plant, Anne L

    2017-03-14

    Cell image segmentation (CIS) is an essential part of quantitative imaging of biological cells. Designing a performance measure and conducting significance testing are critical for evaluating and comparing the CIS algorithms for image-based cell assays in cytometry. Many measures and methods have been proposed and implemented to evaluate segmentation methods. However, computing the standard errors (SE) of the measures and their correlation coefficient is not described, and thus the statistical significance of performance differences between CIS algorithms cannot be assessed. We propose the total error rate (TER), a novel performance measure for segmenting all cells in the supervised evaluation. The TER statistically aggregates all misclassification error rates (MER) by taking cell sizes as weights. The MERs are for segmenting each single cell in the population. The TER is fully supported by the pairwise comparisons of MERs using 106 manually segmented ground-truth cells with different sizes and seven CIS algorithms taken from ImageJ. Further, the SE and 95% confidence interval (CI) of TER are computed based on the SE of MER that is calculated using the bootstrap method. An algorithm for computing the correlation coefficient of TERs between two CIS algorithms is also provided. Hence, the 95% CI error bars can be used to classify CIS algorithms. The SEs of TERs and their correlation coefficient can be employed to conduct the hypothesis testing, while the CIs overlap, to determine the statistical significance of the performance differences between CIS algorithms. A novel measure TER of CIS is proposed. The TER's SEs and correlation coefficient are computed. Thereafter, CIS algorithms can be evaluated and compared statistically by conducting the significance testing.

  9. Significant release of shear energy of the North Korean nuclear test on February 12, 2013

    NASA Astrophysics Data System (ADS)

    Barth, Andreas

    2014-07-01

    On February 12, 2013 the Democratic People's Republic of Korea (DPRK) carried out an announced nuclear test, which was the third after tests conducted in 2006 and 2009. An important task in discriminating a man-made explosion and a natural tectonic earthquake is the analysis of seismic waveforms. To determine the isotropic and non-isotropic characteristics of the detonation source, I invert long-period seismic data for the full seismic moment tensor to match the observed seismic signals by synthetic waveforms based on a 3D Earth model. Here, I show that the inversion of long-period seismic data of the 2013 test reveals a clear explosive (isotropic) component combined with a significant release of shear energy by the double-couple part of the moment tensor. While the isotropic part of the nuclear test in 2009 was similar to that in 2013, the double-couple part was lower by a factor of 0.55 compared to the explosion in 2013. Moreover, the ratio of the isotropic seismic moments of the 2013 and 2009 nuclear tests is 1.4 ± 0.1 and lower than published estimations of the yield ratio, which indicates the importance of considering the release of shear energy. The determined orientation of the double-couple fault plane is parallel to the dominating geologic fault structures NNE-SSW to NE-SW, but the calculated normal faulting mechanism does not correspond to the general tectonic strike-slip regime. Thus, explanations for the enhanced release of shear energy might be induced dip-slip motion pre-stressed by the previous test or near source damaging effects due to a changed containment of the nuclear explosion.

  10. Significance tests to determine the direction of effects in linear regression models.

    PubMed

    Wiedermann, Wolfgang; Hagmann, Michael; von Eye, Alexander

    2015-02-01

    Previous studies have discussed asymmetric interpretations of the Pearson correlation coefficient and have shown that higher moments can be used to decide on the direction of dependence in the bivariate linear regression setting. The current study extends this approach by illustrating that the third moment of regression residuals may also be used to derive conclusions concerning the direction of effects. Assuming non-normally distributed variables, it is shown that the distribution of residuals of the correctly specified regression model (e.g., Y is regressed on X) is more symmetric than the distribution of residuals of the competing model (i.e., X is regressed on Y). Based on this result, 4 one-sample tests are discussed which can be used to decide which variable is more likely to be the response and which one is more likely to be the explanatory variable. A fifth significance test is proposed based on the differences of skewness estimates, which leads to a more direct test of a hypothesis that is compatible with direction of dependence. A Monte Carlo simulation study was performed to examine the behaviour of the procedures under various degrees of associations, sample sizes, and distributional properties of the underlying population. An empirical example is given which illustrates the application of the tests in practice. © 2014 The British Psychological Society.

  11. Laboratory testing for monoclonal gammopathies: Focus on monoclonal gammopathy of undetermined significance and smoldering multiple myeloma.

    PubMed

    Willrich, Maria A V; Murray, David L; Kyle, Robert A

    2017-05-04

    Monoclonal gammopathies (MG) are defined by increased proliferation of clonal plasma cells, resulting in a detectable abnormality called monoclonal component or M-protein. Detection of the M-protein as either narrow peaks on protein electrophoresis and discrete bands on immunofixation is the defining feature of MG. MG are classified as low-tumor burden disorders, pre-malignancies and malignancies. Since significant disease can be present at any level, several different tests are employed in order to encompass the inherent diverse nature of the M-proteins. In this review, we discuss the main characteristics and limitations of clinical assays to detect M-proteins: protein electrophoresis, immunofixation, immunoglobulin quantitation, serum free light chains and heavy-light chain assays, as well as the newly developed MALDI-TOF mass spectrometric methods. In addition, the definitions of the pre-malignancies monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM), as well as monoclonal gammopathy of renal significance (MGRS) are presented in the context of the 2014 international guidelines for definition of myeloma requiring treatment, and the role of the laboratory in test selection for screening and monitoring these conditions is highlighted. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  12. Performance on the Farnsworth-Munsell 100-Hue Test Is Significantly Related to Nonverbal IQ.

    PubMed

    Cranwell, Matthew B; Pearce, Bradley; Loveridge, Camilla; Hurlbert, Anya C

    2015-05-01

    The Farnsworth-Munsell 100-Hue test (FM100) is a standardized measure of chromatic discrimination, based on colored cap-sorting, which has been widely used in both adults and children. Its dependence on seriation ability raises questions as to its universal suitability and accuracy in assessing purely sensory discrimination. This study investigates how general intellectual ability relates to performance on both the FM100 and a new computer-based chromatic discrimination threshold test, across different age groups in both typical and atypical development. Participants were divided into two main age groups, children (6-15 years) and young adults (16-25 years), with each group further subdivided into typically developing (TD; three groups; TD 6-7 years, TD 8-9 years, TD Adult) individuals and atypically developing individuals, all but one carrying a diagnosis of Autism Spectrum Disorders (ASD; two groups; atypically developing [ATY] child 7-15 years, ASD Adult). General intelligence was measured using the Wechsler Abbreviated Intelligence Scale and Wechsler Intelligence Scale for Children. All participants completed the FM100. Both child groups also completed a computer-based chromatic discrimination threshold test, which assessed discrimination along cone-opponent ("red-green," "blue-yellow") and luminance cardinal axes using a controlled staircase procedure. Farnsworth-Munsell 100-Hue test performance was better in adults than in children. Furthermore, performance significantly positively correlated with nonverbal intelligence quotient (NVIQ) for all child groups and the young adult ASD group. The slope of this relationship was steeper for the ASD than TD groups. Performance on the chromatic discrimination threshold test was not significantly related to any IQ measure. Regression models reveal that chromatic discrimination threshold, although a significant predictor of FM100 performance when used alone, is a weaker predictor than NVIQ used alone or in combination

  13. Significant-Loophole-Free Test of Bell's Theorem with Entangled Photons

    NASA Astrophysics Data System (ADS)

    Giustina, Marissa; Versteegh, Marijn A. M.; Wengerowsky, Sören; Handsteiner, Johannes; Hochrainer, Armin; Phelan, Kevin; Steinlechner, Fabian; Kofler, Johannes; Larsson, Jan-Åke; Abellán, Carlos; Amaya, Waldimar; Pruneri, Valerio; Mitchell, Morgan W.; Beyer, Jörn; Gerrits, Thomas; Lita, Adriana E.; Shalm, Lynden K.; Nam, Sae Woo; Scheidl, Thomas; Ursin, Rupert; Wittmann, Bernhard; Zeilinger, Anton

    2015-12-01

    Local realism is the worldview in which physical properties of objects exist independently of measurement and where physical influences cannot travel faster than the speed of light. Bell's theorem states that this worldview is incompatible with the predictions of quantum mechanics, as is expressed in Bell's inequalities. Previous experiments convincingly supported the quantum predictions. Yet, every experiment requires assumptions that provide loopholes for a local realist explanation. Here, we report a Bell test that closes the most significant of these loopholes simultaneously. Using a well-optimized source of entangled photons, rapid setting generation, and highly efficient superconducting detectors, we observe a violation of a Bell inequality with high statistical significance. The purely statistical probability of our results to occur under local realism does not exceed 3.74 ×10-31 , corresponding to an 11.5 standard deviation effect.

  14. Clinical significance of the mixing test in laboratory diagnoses of lupus anticoagulant: the fate of the mixing test in integrated lupus anticoagulant test systems.

    PubMed

    Hong, Sung Kuk; Hwang, Sang Mee; Kim, Ji-Eun; Kim, Hyun Kyung

    2012-12-01

    The mixing test is used to determine the presence of inhibitors in laboratory diagnoses of lupus anticoagulant. Updated international guidelines state that an integrated lupus anticoagulant test system does not require the mixing test; an appraisal of the mixing tests in integrated lupus anticoagulant test systems is, therefore, required. We investigated the clinical relevance of mixing tests by using the best cutoff value of the mixing test through thrombotic risk analysis. A retrospective analysis was performed on 525 specimens with positive screening tests by using two integrated lupus anticoagulant tests: diluted Russell's Viper venom (dRVVT) and silica clotting time. The diagnostic performance of two interpretation formulas (percentage correction, Rosner index) was assessed, and the thrombotic risk of a subgroup based on the mixing results was investigated. Finally, the thrombotic risk of lupus anticoagulant positivity based on the integrated lupus anticoagulant test system procedures was assessed for the appraisal of mixing test exclusion in integrated lupus anticoagulant test systems. The best cutoff values of mixing test interpretation methods based on dRVVT were as follows: 60.1% for percentage correction and 15.7 for Rosner index. There was no substantial difference in the thrombotic risk between percentage correction and the Rosner index. The mixing-positive group showed a higher lupus anticoagulant titer and higher thrombotic risk than the mixing-negative group. However, even the mixing-negative group carried a significant risk of thrombosis. Finally, lupus anticoagulant positivity determined by the updated two-step procedure (screening and confirmation tests) showed higher thrombotic risk than that determined by the traditional three-step procedure (screening, mixing, and confirmation tests). Although a positive mixing result can predict a high risk of thrombosis, negative mixing results are also associated with a substantial thrombotic risk. The

  15. Association between micronucleus frequency and cervical intraepithelial neoplasia grade in Thinprep cytological test and its significance.

    PubMed

    Shi, Yong-Hua; Wang, Bo-Wei; Tuokan, Talaf; Li, Qiao-Zhi; Zhang, Ya-Jing

    2015-01-01

    A micronucleus is an additional small nucleus formed due to chromosomes or chromosomal fragments fail to be incorporated into the nucleus during cell division. In this study, we assessed the utility of micronucleus counting as a screening tool in cervical precancerous lesions in Thinprep cytological test smears under oil immersion. High risk HPV was also detected by hybrid capture-2 in Thinprep cytological test smears. Our results showed that micronucleus counting was significantly higher in high-grade squamous intraepithelial lesion (HSIL) and invasive carcinoma cases compared to low-grade squamous intraepithelial lesion (LSIL) and non-neoplastic cases. Receiver operating characteristic (ROC) curve analysis revealed that micronucleus counting possessed a high degree of sensitivity and specificity for identifying HSIL and invasive carcinoma. Cut-off of 7.5 for MN counting gave a sensitivity of 89.6% and a specificity of 66.7% (P = 0.024 and AUC = 0.892) for detecting HSIL and invasive carcinoma lesions. Multiple linear regression analysis showed that only HSIL and invasive cancer lesions not age, duration of marital life and number of pregnancy are significantly associated with MN counting. The positive rate of high risk HPV was distinctly higher in LSIL, HSIL and invasive cancer than that in non-neoplstic categories. In conclusions, MN evaluation may be viewed as an effective biomarker for cervical cancer screening. The combination of MN count with HPV DNA detection and TCT may serve as an effective means to screen precancerous cervical lesions in most developing nations.

  16. Clinical Features of Congenital Adrenal Insufficiency Including Growth Patterns and Significance of ACTH Stimulation Test

    PubMed Central

    Koh, Ji Won; Kim, Gu Hwan; Yoo, Han Wook

    2013-01-01

    Congenital adrenal insufficiency is caused by specific genetic mutations. Early suspicion and definite diagnosis are crucial because the disease can precipitate a life-threatening hypovolemic shock without prompt treatment. This study was designed to understand the clinical manifestations including growth patterns and to find the usefulness of ACTH stimulation test. Sixteen patients with confirmed genotyping were subdivided into three groups according to the genetic study results: congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH, n=11), congenital lipoid adrenal hyperplasia (n=3) and X-linked adrenal hypoplasia congenita (n=2). Bone age advancement was prominent in patients with CAH especially after 60 months of chronologic age (n=6, 67%). They were diagnosed in older ages in group with bone age advancement (P<0.05). Comorbid conditions such as obesity, mental retardation, and central precocious puberty were also prominent in this group. In conclusion, this study showed the importance of understanding the clinical symptoms as well as genetic analysis for early diagnosis and management of congenital adrenal insufficiency. ACTH stimulation test played an important role to support the diagnosis and serum 17-hydroxyprogesterone levels were significantly elevated in all of the CAH patients. The test will be important for monitoring growth and puberty during follow up of patients with congenital adrenal insufficiency. PMID:24265530

  17. Clinical features of congenital adrenal insufficiency including growth patterns and significance of ACTH stimulation test.

    PubMed

    Koh, Ji Won; Kim, Gu Hwan; Yoo, Han Wook; Yu, Jeesuk

    2013-11-01

    Congenital adrenal insufficiency is caused by specific genetic mutations. Early suspicion and definite diagnosis are crucial because the disease can precipitate a life-threatening hypovolemic shock without prompt treatment. This study was designed to understand the clinical manifestations including growth patterns and to find the usefulness of ACTH stimulation test. Sixteen patients with confirmed genotyping were subdivided into three groups according to the genetic study results: congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH, n=11), congenital lipoid adrenal hyperplasia (n=3) and X-linked adrenal hypoplasia congenita (n=2). Bone age advancement was prominent in patients with CAH especially after 60 months of chronologic age (n=6, 67%). They were diagnosed in older ages in group with bone age advancement (P<0.05). Comorbid conditions such as obesity, mental retardation, and central precocious puberty were also prominent in this group. In conclusion, this study showed the importance of understanding the clinical symptoms as well as genetic analysis for early diagnosis and management of congenital adrenal insufficiency. ACTH stimulation test played an important role to support the diagnosis and serum 17-hydroxyprogesterone levels were significantly elevated in all of the CAH patients. The test will be important for monitoring growth and puberty during follow up of patients with congenital adrenal insufficiency.

  18. A Multi-Core Parallelization Strategy for Statistical Significance Testing in Learning Classifier Systems.

    PubMed

    Rudd, James; Moore, Jason H; Urbanowicz, Ryan J

    2013-11-01

    Permutation-based statistics for evaluating the significance of class prediction, predictive attributes, and patterns of association have only appeared within the learning classifier system (LCS) literature since 2012. While still not widely utilized by the LCS research community, formal evaluations of test statistic confidence are imperative to large and complex real world applications such as genetic epidemiology where it is standard practice to quantify the likelihood that a seemingly meaningful statistic could have been obtained purely by chance. LCS algorithms are relatively computationally expensive on their own. The compounding requirements for generating permutation-based statistics may be a limiting factor for some researchers interested in applying LCS algorithms to real world problems. Technology has made LCS parallelization strategies more accessible and thus more popular in recent years. In the present study we examine the benefits of externally parallelizing a series of independent LCS runs such that permutation testing with cross validation becomes more feasible to complete on a single multi-core workstation. We test our python implementation of this strategy in the context of a simulated complex genetic epidemiological data mining problem. Our evaluations indicate that as long as the number of concurrent processes does not exceed the number of CPU cores, the speedup achieved is approximately linear.

  19. Single decoupled blasthole tests and the significance of the results to presplitting and boulder busting

    SciTech Connect

    Tariq, S.M.; Worsey, P.N.; Wilson, J.W.

    1996-12-01

    The position of a major joint in relation to a blasthole has a significant effect in presplitting. Broad research into the combined effects of firing two decoupled blastholes has been performed in the past. The effects of joints simulated between two blastholes has also been evaluated. However, no attempt has been made to investigate the splitting effects produced by firing a single decoupled blasthole. This paper presents the results of such an investigation. A series of model tests was carried out in specially prepared 12 x 9 x 6 inches concrete blocks each with a 3/8 inch blasthole, loaded with 15-grain detonating cord. To simulate a semi-infinite burden similar to field presplit conditions, the blocks were lightly constrained. Before tightening the blocks, wooden spacers approximately three inches thick were placed on one end of the block to provide a free face. Additional experiments were conducted without constraints to ascertain the resulting fracture pattern in boulder blasting mode. It was found, if the blasthole is relatively near to the free face the angle of crater is greater. It was also observed that, at a distance approximately five times the diameter of the blasthole, the cratering ceases. During these tests a recurring split appeared all the way back to the abutted end of the blocks far in excess of what is expected in presplitting. This was not anticipated. An extensive investigation was undertaken to find an application in presplitting and boulder busting for this new phenomenon. It was found that when the blasthole is placed close to the abutted end of the block, it can produce a significantly longer split than when it is placed near the middle of the block. This was also verified in tests without constraints, which illustrates its potential for application in boulder blasting.

  20. Hypersensitivity testing for Aspergillus fumigatus IgE is significantly more sensitive than testing for Aspergillus niger IgE.

    PubMed

    Selvaggi, Thomas A; Walco, Jeremy P; Parikh, Sujal; Walco, Gary A

    2012-02-01

    We sought to determine if sufficient redundancy exists between specific IgE testing for Aspergillus fumigatus and Aspergillus niger to eliminate one of the assays in determining Aspergillus hypersensitivity. We reviewed regional laboratory results comparing A fumigatus-specific IgE with A niger-specific IgE using the Pharmacia UniCAP system (Pharmacia, Kalamazoo, MI). By using the Fisher exact test as an index of concordance among paired results, we showed a significant difference between 109 paired samples for the presence of specific IgE to A fumigatus and A niger (P < .0001). Of these specimens, 94 were negative for IgE to both species, 10 were positive for A fumigatus and negative for A niger; no specimen was positive for A niger and negative for A fumigatus. We conclude that A fumigatus-specific IgE is sufficient to detect Aspergillus hypersensitivity. The assay for A niger-specific IgE is redundant, less sensitive, and unnecessary if the assay for specific IgE for A fumigatus is performed.

  1. A powerful test of independent assortment that determines genome-wide significance quickly and accurately

    PubMed Central

    Stewart, W C L; Hager, V R

    2016-01-01

    In the analysis of DNA sequences on related individuals, most methods strive to incorporate as much information as possible, with little or no attention paid to the issue of statistical significance. For example, a modern workstation can easily handle the computations needed to perform a large-scale genome-wide inheritance-by-descent (IBD) scan, but accurate assessment of the significance of that scan is often hindered by inaccurate approximations and computationally intensive simulation. To address these issues, we developed gLOD—a test of co-segregation that, for large samples, models chromosome-specific IBD statistics as a collection of stationary Gaussian processes. With this simple model, the parametric bootstrap yields an accurate and rapid assessment of significance—the genome-wide corrected P-value. Furthermore, we show that (i) under the null hypothesis, the limiting distribution of the gLOD is the standard Gumbel distribution; (ii) our parametric bootstrap simulator is approximately 40 000 times faster than gene-dropping methods, and it is more powerful than methods that approximate the adjusted P-value; and, (iii) the gLOD has the same statistical power as the widely used maximum Kong and Cox LOD. Thus, our approach gives researchers the ability to determine quickly and accurately the significance of most large-scale IBD scans, which may contain multiple traits, thousands of families and tens of thousands of DNA sequences. PMID:27245422

  2. An adaptive resampling test for detecting the presence of significant predictors

    PubMed Central

    McKeague, Ian W.; Qian, Min

    2015-01-01

    This paper investigates marginal screening for detecting the presence of significant predictors in high-dimensional regression. Screening large numbers of predictors is a challenging problem due to the non-standard limiting behavior of post-model-selected estimators. There is a common misconception that the oracle property for such estimators is a panacea, but the oracle property only holds away from the null hypothesis of interest in marginal screening. To address this difficulty, we propose an adaptive resampling test (ART). Our approach provides an alternative to the popular (yet conservative) Bonferroni method of controlling familywise error rates. ART is adaptive in the sense that thresholding is used to decide whether the centered percentile bootstrap applies, and otherwise adapts to the non-standard asymptotics in the tightest way possible. The performance of the approach is evaluated using a simulation study and applied to gene expression data and HIV drug resistance data. PMID:27073292

  3. An enhanced cluster analysis program with bootstrap significance testing for ecological community analysis

    USGS Publications Warehouse

    McKenna, J.E.

    2003-01-01

    The biosphere is filled with complex living patterns and important questions about biodiversity and community and ecosystem ecology are concerned with structure and function of multispecies systems that are responsible for those patterns. Cluster analysis identifies discrete groups within multivariate data and is an effective method of coping with these complexities, but often suffers from subjective identification of groups. The bootstrap testing method greatly improves objective significance determination for cluster analysis. The BOOTCLUS program makes cluster analysis that reliably identifies real patterns within a data set more accessible and easier to use than previously available programs. A variety of analysis options and rapid re-analysis provide a means to quickly evaluate several aspects of a data set. Interpretation is influenced by sampling design and a priori designation of samples into replicate groups, and ultimately relies on the researcher's knowledge of the organisms and their environment. However, the BOOTCLUS program provides reliable, objectively determined groupings of multivariate data.

  4. Technical note: A significance test for data-sparse zones in scatter plots

    NASA Astrophysics Data System (ADS)

    Vetrova, V. V.; Bardsley, W. E.

    2012-04-01

    Data-sparse zones in scatter plots of hydrological variables can be of interest in various contexts. For example, a well-defined data-sparse zone may indicate inhibition of one variable by another. It is of interest therefore to determine whether data-sparse regions in scatter plots are of sufficient extent to be beyond random chance. We consider the specific situation of data-sparse regions defined by a linear internal boundary within a scatter plot defined over a rectangular region. An Excel VBA macro is provided for carrying out a randomisation-based significance test of the data-sparse region, taking into account both the within-region number of data points and the extent of the region. Example applications are given with respect to a rainfall time series from Israel and also to validation scatter plots from a seasonal forecasting model for lake inflows in New Zealand.

  5. Technical Note: A significance test for data-sparse zones in scatter plots

    NASA Astrophysics Data System (ADS)

    Vetrova, V. V.; Bardsley, W. E.

    2012-01-01

    Data-sparse zones in scatter plots of hydrological variables can be of interest in various contexts. For example, a well-defined data-sparse zone may indicate inhibition of one variable by another. It is of interest therefore to determine whether data-sparse regions in scatter plots are of sufficient extent to be beyond random chance. We consider the specific situation of data-sparse regions defined by a linear internal boundary within a scatter plot defined over a rectangular region. An Excel VBA macro is provided for carrying out a randomisation-based significance test of the data-sparse region, taking into account both the within-region number of data points and the extent of the region. Example applications are given with respect to a rainfall time series from Israel and to validation scatter plots from a seasonal forecasting model for lake inflows in New Zealand.

  6. A Significance Test for Inferring Affiliation Networks from Spatio-Temporal Data

    PubMed Central

    Furmston, Thomas; Morton, A. Jennifer; Hailes, Stephen

    2015-01-01

    Scientists have long been interested in studying social structures within groups of gregarious animals. However, obtaining evidence about interactions between members of a group is difficult. Recent technologies, such as Global Positioning System technology, have made it possible to obtain a vast wealth of animal movement data, but inferring the underlying (latent) social structure of the group from such data remains an important open problem. While intuitively appealing measures of social interaction exist in the literature, they typically lack formal statistical grounding. In this article, we provide a statistical approach to the problem of inferring the social structure of a group from the movement patterns of its members. By constructing an appropriate null model, we are able to construct a significance test to detect meaningful affiliations between members of the group. We demonstrate our method on large-scale real-world data sets of positional data of flocks of Merino sheep, Ovis aries. PMID:26192280

  7. Testing statistical significance scores of sequence comparison methods with structure similarity

    PubMed Central

    Hulsen, Tim; de Vlieg, Jacob; Leunissen, Jack AM; Groenen, Peter MA

    2006-01-01

    Background In the past years the Smith-Waterman sequence comparison algorithm has gained popularity due to improved implementations and rapidly increasing computing power. However, the quality and sensitivity of a database search is not only determined by the algorithm but also by the statistical significance testing for an alignment. The e-value is the most commonly used statistical validation method for sequence database searching. The CluSTr database and the Protein World database have been created using an alternative statistical significance test: a Z-score based on Monte-Carlo statistics. Several papers have described the superiority of the Z-score as compared to the e-value, using simulated data. We were interested if this could be validated when applied to existing, evolutionary related protein sequences. Results All experiments are performed on the ASTRAL SCOP database. The Smith-Waterman sequence comparison algorithm with both e-value and Z-score statistics is evaluated, using ROC, CVE and AP measures. The BLAST and FASTA algorithms are used as reference. We find that two out of three Smith-Waterman implementations with e-value are better at predicting structural similarities between proteins than the Smith-Waterman implementation with Z-score. SSEARCH especially has very high scores. Conclusion The compute intensive Z-score does not have a clear advantage over the e-value. The Smith-Waterman implementations give generally better results than their heuristic counterparts. We recommend using the SSEARCH algorithm combined with e-values for pairwise sequence comparisons. PMID:17038163

  8. Association between micronucleus frequency and cervical intraepithelial neoplasia grade in Thinprep cytological test and its significance

    PubMed Central

    Shi, Yong-Hua; Wang, Bo-Wei; Tuokan, Talaf; Li, Qiao-Zhi; Zhang, Ya-Jing

    2015-01-01

    A micronucleus is an additional small nucleus formed due to chromosomes or chromosomal fragments fail to be incorporated into the nucleus during cell division. In this study, we assessed the utility of micronucleus counting as a screening tool in cervical precancerous lesions in Thinprep cytological test smears under oil immersion. High risk HPV was also detected by hybrid capture-2 in Thinprep cytological test smears. Our results showed that micronucleus counting was significantly higher in high-grade squamous intraepithelial lesion (HSIL) and invasive carcinoma cases compared to low-grade squamous intraepithelial lesion (LSIL) and non-neoplastic cases. Receiver operating characteristic (ROC) curve analysis revealed that micronucleus counting possessed a high degree of sensitivity and specificity for identifying HSIL and invasive carcinoma. Cut-off of 7.5 for MN counting gave a sensitivity of 89.6% and a specificity of 66.7% (P = 0.024 and AUC = 0.892) for detecting HSIL and invasive carcinoma lesions. Multiple linear regression analysis showed that only HSIL and invasive cancer lesions not age, duration of marital life and number of pregnancy are significantly associated with MN counting. The positive rate of high risk HPV was distinctly higher in LSIL, HSIL and invasive cancer than that in non-neoplstic categories. In conclusions, MN evaluation may be viewed as an effective biomarker for cervical cancer screening. The combination of MN count with HPV DNA detection and TCT may serve as an effective means to screen precancerous cervical lesions in most developing nations. PMID:26339413

  9. Significance of fully automated tests for the diagnosis of antiphospholipid syndrome.

    PubMed

    Oku, Kenji; Amengual, Olga; Kato, Masaru; Bohgaki, Toshiyuki; Horita, Tetsuya; Yasuda, Shinsuke; Sakamoto, Naoya; Ieko, Masahiro; Norman, Gary L; Atsumi, Tatsuya

    2016-10-01

    Antiphospholipid antibodies (aPLs) can vary both immunologically and functionally, thus it is important to effectively and correctly identify their presence when diagnosing antiphospholipid syndrome. Furthermore, since many immunological/functional tests are necessary to measure aPLs, complete examinations are often not performed in many cases due to significant burden on the testing departments. To address this issue, we measured aPLs defined according to the classification criteria (anticardiolipin antibody: aCL) IgG/IgM and anti-β2 glycoprotein I antibody (aβ2GPI) (IgG/IgM) as well as non-criteria antibodies (aCL IgA, aβ2GPI IgA and aβ2GPI domain I), in a cohort of 211 patients (61 APS, 140 disease controls and 10 healthy individuals). APLs were measured using a fully automated chemiluminescent immunoassay instrument (BIO-FLASH®/ACL AcuStar®) and with conventional ELISA tests. We demonstrated that both sensitivity and accuracy of diagnosis of aCL IgG and aβ2GPI IgG were high, in agreement with the past reports. When multiple aPLs were examined, the accuracy of diagnosis increased. The proportion of APS patients that were positive for 2 or more types of aPLs (47/61, 77%) was higher than that of patients with systemic lupus erythematosus (SLE)(3/37, 9%), those with non-SLE connective tissues diseases (1/53,2%), those with other diseases or healthy volunteers. Based on these findings, it was concluded that the fully automated chemiluminescent immunoassay instrument, which allows the simultaneous evaluation of many types of aPLs, offers clear advantages for a more complete, more rapid and less labor-intensive alternative to running multiple ELISA and could help in better diagnosis for suspected APS patients.

  10. The null hypothesis significance test in health sciences research (1995-2006): statistical analysis and interpretation

    PubMed Central

    2010-01-01

    Background The null hypothesis significance test (NHST) is the most frequently used statistical method, although its inferential validity has been widely criticized since its introduction. In 1988, the International Committee of Medical Journal Editors (ICMJE) warned against sole reliance on NHST to substantiate study conclusions and suggested supplementary use of confidence intervals (CI). Our objective was to evaluate the extent and quality in the use of NHST and CI, both in English and Spanish language biomedical publications between 1995 and 2006, taking into account the International Committee of Medical Journal Editors recommendations, with particular focus on the accuracy of the interpretation of statistical significance and the validity of conclusions. Methods Original articles published in three English and three Spanish biomedical journals in three fields (General Medicine, Clinical Specialties and Epidemiology - Public Health) were considered for this study. Papers published in 1995-1996, 2000-2001, and 2005-2006 were selected through a systematic sampling method. After excluding the purely descriptive and theoretical articles, analytic studies were evaluated for their use of NHST with P-values and/or CI for interpretation of statistical "significance" and "relevance" in study conclusions. Results Among 1,043 original papers, 874 were selected for detailed review. The exclusive use of P-values was less frequent in English language publications as well as in Public Health journals; overall such use decreased from 41% in 1995-1996 to 21% in 2005-2006. While the use of CI increased over time, the "significance fallacy" (to equate statistical and substantive significance) appeared very often, mainly in journals devoted to clinical specialties (81%). In papers originally written in English and Spanish, 15% and 10%, respectively, mentioned statistical significance in their conclusions. Conclusions Overall, results of our review show some improvements in

  11. Significance of T wave normalization in the electrocardiogram during exercise stress test

    SciTech Connect

    Marin, J.J.; Heng, M.K.; Sevrin, R.; Udhoji, V.N.

    1987-12-01

    Although normalization of previously inverted T waves in the ECG is not uncommon during exercise treadmill testing, the clinical significance of this finding is still unclear. This was investigated in 45 patients during thallium-201 exercise testing. Patients with secondary T wave abnormalities on the resting ECG and ischemic exercise ST segment depression were excluded. On the thallium-201 scans, the left ventricle was divided into anterior-septal and inferior-posterior segments; these were considered equivalent to T wave changes in leads V1 and V5, and aVF, respectively. A positive thallium-201 scan was found in 43 of 45 (95%) patients and in 49 of 52 (94%) cardiac segments that showed T wave normalization. When thallium scans and T wave changes were matched to sites of involvement, 76% of T wave normalization in lead aV, was associated with positive thallium scans in the inferior-posterior segments, and 77% of T wave normalization in V1 and V5 was associated with positive thallium scans in the anterior-septal segments. These site correlations were similar for reversible and fixed thallium defects, and for patients not on digoxin therapy. Similar correlations were noted for the sites of T wave changes and coronary artery lesions in 12 patients who had angiography. In patients with a high prevalence for coronary artery disease, exercise T wave normalization is highly specific for the presence of the disease. In addition, it represents predominantly either previous injury or exercise-induced ischemic changes over the site of ECG involvement, rather than reciprocal changes of the opposite ventricular wall.

  12. Negative Predictive Value and Significance of Benign-Appearing Endometrial Cells in Papanicolaou Tests.

    PubMed

    Yu, Jing; Onisko, Agnieszka; Austin, R Marshall

    2017-09-01

    Reporting benign-appearing endometrial cells (nEMCs) in Papanicolaou (Pap) smears of women 40 years and older, introduced in The Bethesda System 2001, may be interpreted as an abnormal finding and lead to unnecessary endometrial biopsies. To our knowledge, this is the first study on the negative predictive value (NPV) of this cytology finding. An 11-year database with 1,036,629 Pap test reports and 121,079 surgical pathology reports identified reports of nEMCs in women 40 years and older with follow-up endometrial histopathology within 6 months. Endometrial carcinoma and atypical endometrial hyperplasia were chosen as relevant outcomes. NPVs were calculated. Bayesian modeling assessed the impact of age, bleeding, and postmenopausal status on risk. NPVs for patients aged 40 to 44 years and 45 to 49 years (99.5% and 99.3%, respectively) were not significantly different. NPVs for patients aged 50 to 54 years, 55 to 59 years, and 60 years and older (97.1%, 95.3%, and 94.5%, respectively) were lower than the NPV for patients aged 40 to 49 years. Bayesian modeling indicated that asymptomatic patients in all age groups 40 years and older have very low risk. Bleeding history increased risk in all age groups, especially in women 50 years and older. nEMCs in Pap test reports of women 40 years and older are a normal cytology finding in premenopausal women, which may result in unnecessary endometrial biopsies. The NPV associated with this finding for women aged 40 to 49 years exceeded 99%.

  13. Metal allergens of growing significance: epidemiology, immunotoxicology, strategies for testing and prevention.

    PubMed

    Forte, Giovanni; Petrucci, Francesco; Bocca, Beatrice

    2008-09-01

    Metal-induced allergic contact dermatitis (ACD) is expressed in a wide range of cutaneous reactions following dermal and systemic exposure to products such as cosmetics and tattoos, detergents, jewellery and piercing, leather tanning, articular prostheses and dental implants. Apart from the well known significance of nickel in developing ACD, other metals such as aluminium, beryllium, chromium, cobalt, copper, gold, iridium, mercury, palladium, platinum, rhodium and titanium represented emerging causes of skin hypersensitivity. Despite the European Union directives that limit the total nickel content in jewellery alloys, the water soluble chromium (VI) in cement, and metals banned in cosmetics, the diffusion of metal-induced ACD remained quite high. On this basis, a review on the epidemiology of metal allergens, the types of exposure, the skin penetration, the immune response, and the protein interaction is motivated. Moreover, in vivo and in vitro tests for the identification and potency of skin-sensitizing metals are here reviewed in a risk assessment framework for the protection of consumer's health. Avenues for ACD prevention and therapy such as observance of maximum allowable metal levels, optimization of metallurgic characteristics, efficacy of chelating agents and personal protection are also discussed.

  14. Significant effects of mild endogenous hormonal changes in humans: considerations for low-dose testing.

    PubMed

    Brucker-Davis, F; Thayer, K; Colborn, T

    2001-03-01

    We review the significant and adverse health effects that can occur with relatively small endogenous hormonal changes in pubertal and adult humans. We discuss the effects of hormonal changes that occur within normal physiologic ranges--such as the rising levels of estrogen in peripuberty, which cause growth spurts at low levels and then the fusion of epiphyses at higher levels--and the hormonal variations during the menstrual cycle and their relation to genital phenotypic changes and intercurrent disease evolution. We turn next to adaptive changes in gonadal and other functions during aging, exercise, stress, starvation, and chronic diseases, which can serve as models for the effects of exogenous, hormonally active compounds. Then we review the states of borderline hormonal imbalances such as subclinical (having few or very mild symptoms, if any) hypothyroidism or hyperthyroidism, glucose intolerance, and other endocrine conditions. Finally, we review the deleterious systemic effects of gonadal imbalance. Information stemming from clinical observations leads to the concept of "no threshold" within the endocrine system and thus illustrates the importance of considering low-dose testing for chemicals that interfere with hormonal activity. We also urge attention to more sensitive, less visible end points such as osteoporosis, increased risk for cardiovascular disease, or cognitive changes.

  15. Variants of Uncertain Significance in BRCA Testing: Evaluation of Surgical Decisions, Risk Perception, and Cancer Distress

    PubMed Central

    Culver, J.O.; Brinkerhoff, C.D.; Clague, J.; Yang, K.; Singh, K.E.; Sand, S.R.; Weitzel, J.N.

    2013-01-01

    Studies suggest that patients carrying a BRCA variant of uncertain significance (VUS) may have lingering confusion concerning results interpretation. Counseling for uninformative BRCA-negative (UN) results is thought to be more straightforward, despite the fact that both results lead to similar methods of empiric cancer risk counseling. This study compared surgical choices and perceptions between 71 patients with VUS results and 714 patients with UN results. All patients underwent genetic counseling because of a personal or family history of breast or ovarian cancer between 1997 and 2010, and completed a two-year follow-up survey. Risk-reducing mastectomy rates in both groups were 7% (p=1.00) and risk-reducing oophorectomy rates were 5% and 3%, respectively (p=0.42). The VUS group reported less cancer distress reduction than the UN group (23.0% versus 35.8%, respectively, p=.043). Over 90% of both groups found the counseling process helpful. Overall, the study suggests that VUS results disclosed in genetic counseling did not cause excessive surgery or exaggerated cancer distress, though patients with a VUS found counseling somewhat less informative or reassuring. Future research on communication of VUS results, including pre-and post-test counseling, is essential for full realization of the potential for genomic medicine. PMID:23323793

  16. Performance characteristics of Pap test, VIA, VILI, HR-HPV testing, cervicography, and colposcopy in diagnosis of significant cervical pathology.

    PubMed

    Longatto-Filho, Adhemar; Naud, Paulo; Derchain, Sophie Fm; Roteli-Martins, Cecília; Tatti, Sílvio; Hammes, Luciano Serpa; Sarian, Luis Otavio; Eržen, Mojca; Branca, Margherita; de Matos, Jean Carlos; Gontijo, Renata; Maeda, Marina Y S; Lima, Temístocles; Costa, Silvano; Syrjänen, Stina; Syrjänen, Kari

    2012-06-01

    We sought to evaluate the performance of diagnostic tools to establish an affordable setting for early detection of cervical cancer in developing countries. We compared the performance of different screening tests and their feasibility in a cohort of over 12,000 women: conventional Pap smear, liquid-based cytology, visual inspection with acetic acid (VIA), visual inspection with Iodine solution (VILI), cervicography, screening colposcopy, and high-risk human papillomavirus (HPV) testing (HR-HPV) collected by physician and by self-sampling. HR-HPV assay collected by the physician has the highest sensitivity (80 %), but high unnecessary referrals to colposcopy (15.1 %). HR-HPV test in self-sampling had a markedly lower (57.1 %) sensitivity. VIA, VILI, and cervicography had a poor sensitivity (47.4, 55, and 28.6 %, respectively). Colposcopy presented with sensitivity of 100 % in detecting CIN2+, but the lowest specificity (66.9 %). Co-testing with VIA and VILI Pap test increased the sensitivity of stand-alone Pap test from 71.6 to 87.1 % and 71.6 to 95 %, respectively, but with high number of unnecessary colposcopies. Co-testing with HR-HPV importantly increased the sensitivity of Pap test (to 86 %), but with high number of unnecessary colposcopies (17.5 %). Molecular tests adjunct to Pap test seems a realistic option to improve the detection of high-grade lesions in population-based screening programs.

  17. Significant Predictors of Test Anxiety among Students with and without Learning Disabilities

    ERIC Educational Resources Information Center

    Whitaker Sena, Jolyn D.; Lowe, Patricia A.; Lee, Steven W. Whitaker Sena, Jolyn D.; Lowe, Patricia A.; Lee, Steven W.

    2007-01-01

    In the present study, the relationship between students with and without learning disabilities (LD) and different aspects of test anxiety was examined on a new multidimensional measure of test anxiety. A sample of 774 elementary and secondary school students--195 students with LD and 579 students not identified with LD--completed the "Test Anxiety…

  18. Statistical and Practical Significance of the Likelihood Ratio Test of the Linear Logistic Test Model versus the Rasch Model

    ERIC Educational Resources Information Center

    Alexandrowicz, Rainer W.

    2011-01-01

    The linear logistic test model (LLTM) is a valuable and approved tool in educational research, as it allows for modelling cognitive components involved in a cognitive task. It allows for a rigorous assessment of fit by means of a Likelihood Ratio Test (LRT). This approach is genuine to the Rasch family of models, yet it suffers from the unsolved…

  19. Significance of physical performance tests for patients with low back pain.

    PubMed

    Pfingsten, Michael; Lueder, Susanne; Luedtke, Kerstin; Petzke, Frank; Hildebrandt, Jan

    2014-07-01

    Several research groups established functional tests to obtain performance data for mobility-related activities in patients with low back pain (LBP). In our study we aimed to assess the construct validity and associations with other measures of a battery of functional tests in relationship to physical performance on the one hand and physical capacity and variables of pain, disability and psychological variables on the other. Eight physical performance tests of everyday activities such as climbing stairs, picking up an object from the floor, bending forward, and sitting up from supine position etc. were evaluated in 106 patients with LBP and 106 control subjects. Distribution of results in each test demonstrated a marked overlap in a number of tests between those with and those without back pain. In a factor analysis we found pronounced differences in the factorial structure of the data between patients and control subjects as well in the bivariate correlations between functional test results. There was a strong relationship between self-report disability rating (FFbH-R) and physical performance tests especially in patients whereas physical capacity tests had less relationship in patients and not at all in the control subjects. In contrast to the past and present literature, our results suggest that physical performance tests have an inherent problem to sharply differentiate patients with back pain from healthy controls and problems with inter-rater reliability. Physical performance seems to be more a matter of patients' perception of generalized disability than of restricted function. Wiley Periodicals, Inc.

  20. Do School-Based Tutoring Programs Significantly Improve Student Performance on Standardized Tests?

    ERIC Educational Resources Information Center

    Rothman, Terri; Henderson, Mary

    2011-01-01

    This study used a pre-post, nonequivalent control group design to examine the impact of an in-district, after-school tutoring program on eighth grade students' standardized test scores in language arts and mathematics. Students who had scored in the near-passing range on either the language arts or mathematics aspect of a standardized test at the…

  1. An on-line exact small-sample test of significance for extended matching tasks.

    PubMed

    Gillett, R

    2001-11-01

    An extension of the traditional matching paradigm that enables researchers to test a variety of new experimental hypotheses is outlined. An on-line computer program that provides an exact small-sample test of hypotheses in the extended matching paradigm is described. The program, which has an intuitive graphical interface, may be accessed and executed via the Internet by using an ordinary browser.

  2. Classifying and scoring of molecules with the NGN: new datasets, significance tests, and generalization

    PubMed Central

    2010-01-01

    This paper demonstrates how a Neural Grammar Network learns to classify and score molecules for a variety of tasks in chemistry and toxicology. In addition to a more detailed analysis on datasets previously studied, we introduce three new datasets (BBB, FXa, and toxicology) to show the generality of the approach. A new experimental methodology is developed and applied to both the new datasets as well as previously studied datasets. This methodology is rigorous and statistically grounded, and ultimately culminates in a Wilcoxon significance test that proves the effectiveness of the system. We further include a complete generalization of the specific technique to arbitrary grammars and datasets using a mathematical abstraction that allows researchers in different domains to apply the method to their own work. Background Our work can be viewed as an alternative to existing methods to solve the quantitative structure-activity relationship (QSAR) problem. To this end, we review a number approaches both from a methodological and also a performance perspective. In addition to these approaches, we also examined a number of chemical properties that can be used by generic classifier systems, such as feed-forward artificial neural networks. In studying these approaches, we identified a set of interesting benchmark problem sets to which many of the above approaches had been applied. These included: ACE, AChE, AR, BBB, BZR, Cox2, DHFR, ER, FXa, GPB, Therm, and Thr. Finally, we developed our own benchmark set by collecting data on toxicology. Results Our results show that our system performs better than, or comparatively to, the existing methods over a broad range of problem types. Our method does not require the expert knowledge that is necessary to apply the other methods to novel problems. Conclusions We conclude that our success is due to the ability of our system to: 1) encode molecules losslessly before presentation to the learning system, and 2) leverage the design of

  3. Everyday cognitive functioning in cardiac patients: relationships between self-report, report of a significant other and cognitive test performance.

    PubMed

    Elliott, Peter C; Smith, Geoff; Ernest, Christine S; Murphy, Barbara M; Worcester, Marian U C; Higgins, Rosemary O; Le Grande, Michael R; Goble, Alan J; Andrewes, David; Tatoulis, James

    2010-01-01

    Candidates for cardiac bypass surgery often experience cognitive decline. Such decline is likely to affect their everyday cognitive functioning. The aim of the present study was to compare cardiac patients' ratings of their everyday cognitive functioning against significant others' ratings and selected neuropsychological tests. Sixty-nine patients completed a battery of standardised cognitive tests. Patients and significant others also completed the Everyday Function Questionnaire independently of each other. Patient and significant other ratings of patients' everyday cognitive difficulties were found to be similar. Despite the similarities in ratings of difficulties, some everyday cognitive tasks were attributed to different processes. Patients' and significant others' ratings were most closely associated with the neuropsychological test of visual memory. Tests of the patients' verbal memory and fluency were only related to significant others' ratings. Test scores of attention and planning were largely unrelated to ratings by either patients or their significant others.

  4. Testing significance relative to a fold-change threshold is a TREAT.

    PubMed

    McCarthy, Davis J; Smyth, Gordon K

    2009-03-15

    Statistical methods are used to test for the differential expression of genes in microarray experiments. The most widely used methods successfully test whether the true differential expression is different from zero, but give no assurance that the differences found are large enough to be biologically meaningful. We present a method, t-tests relative to a threshold (TREAT), that allows researchers to test formally the hypothesis (with associated p-values) that the differential expression in a microarray experiment is greater than a given (biologically meaningful) threshold. We have evaluated the method using simulated data, a dataset from a quality control experiment for microarrays and data from a biological experiment investigating histone deacetylase inhibitors. When the magnitude of differential expression is taken into account, TREAT improves upon the false discovery rate of existing methods and identifies more biologically relevant genes. R code implementing our methods is contributed to the software package limma available at http://www.bioconductor.org.

  5. 77 FR 19861 - Certain Polybrominated Diphenylethers; Significant New Use Rule and Test Rule

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-02

    ... obligations if continuing existing uses of PBDEs. If EPA were to learn through comments on this proposed....) However, if EPA were to learn that the only persons that would be subject to the test rule would be...

  6. Avoidance tests with earthworms and springtails: defining the minimum exposure time to observe a significant response.

    PubMed

    Natal-da-Luz, Tiago; Amorim, Mónica J B; Römbke, Jörg; Sousa, José Paulo

    2008-10-01

    Based on the ability of organisms to avoid contaminated soils, avoidance tests have a great potential as early screening tools in lower tier levels of ERA schemes. Aiming at their standardization, the definition of the minimum exposure time necessary to observe an avoidance response to a contaminant is needed. To fill this gap, avoidance tests with earthworms (Eisenia andrei) and springtails (Folsomia candida), comparing distinct time periods (from 1-7 to 1-14 days, respectively), were performed using the artificial OECD soil and reference chemicals for each test organism. Results showed that for both organisms a clear response within 24 h of exposure can be obtained. This rapid response enhances the utility of the test for "on site" analysis to evaluate contaminated sites.

  7. Methodology to identify risk-significant components for inservice inspection and testing

    SciTech Connect

    Anderson, M.T.; Hartley, R.S.; Jones, J.L. Jr.; Kido, C.; Phillips, J.H.

    1992-08-01

    Periodic inspection and testing of vital system components should be performed to ensure the safe and reliable operation of Department of Energy (DOE) nuclear processing facilities. Probabilistic techniques may be used to help identify and rank components by their relative risk. A risk-based ranking would allow varied DOE sites to implement inspection and testing programs in an effective and cost-efficient manner. This report describes a methodology that can be used to rank components, while addressing multiple risk issues.

  8. Clinical Parameter for Deciding the BRAFV600E Mutation Test in Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance Thyroid Nodules: US Features According to TIRADS.

    PubMed

    Rho, Miribi; Kim, Eun-Kyung; Moon, Hee Jung; Yoon, Jung Hyun; Park, Vivian Y; Han, Kyunghwa; Kwak, Jin Young

    2017-09-04

    This study aimed to investigate the usefulness of a thyroid imaging reporting and data system (TIRADS) to select thyroid nodules with atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) cytology for additional BRAF mutation testing. Three hundred three thyroid nodules were included. Statistical analysis was performed at both patient and nodule levels according to BRAF mutation positivity and clinical factors. Univariate and multivariate logistic regression analyses were performed to assess independent associations between BRAF mutation positivity and clinical factors. Of 303 AUS/FLUS nodules, 16 (5.3%) of 303 nodules had the BRAF mutation. The frequency of the BRAF mutation according to the TIRADS was 35.7% for category 5, 10.8% for category 4c, 2.5% for category 4b, 1.1% for category 4a, and 0% for category 3 nodules (P < 0.001). On multivariate analysis, BRAF mutation positivity was significantly associated with high suspicion on the TIRADS (odds ratio, 15.247; P < 0.001). In conclusion, the ultrasonography patterns of the TIRADS can be used as a clinical parameter for deciding the BRAF mutation test in thyroid nodules with AUS/FLUS cytology.

  9. A simple and effective decision rule for choosing a significance test to protect against non-normality.

    PubMed

    Zimmerman, Donald W

    2011-11-01

    There is no formal and generally accepted procedure for choosing an appropriate significance test for sample data when the assumption of normality is doubtful. Various tests of normality that have been proposed over the years have been found to have limited usefulness, and sometimes a preliminary test makes the situation worse. The present paper investigates a specific and easily applied rule for choosing between a parametric and non-parametric test, the Student t test and the Wilcoxon-Mann-Whitney test, that does not require a preliminary significance test of normality. Simulations reveal that the rule, which can be applied to sample data automatically by computer software, protects the Type I error rate and increases power for various sample sizes, significance levels, and non-normal distribution shapes. Limitations of the procedure in the case of heterogeneity of variance are discussed.

  10. Significance of a Positive Toxoplasma Immunoglobulin M Test Result in the United States.

    PubMed

    Dhakal, Reshika; Gajurel, Kiran; Pomares, Christelle; Talucod, Jeanne; Press, Cynthia J; Montoya, Jose G

    2015-11-01

    A positive Toxoplasma immunoglobulin M (IgM) result is often interpreted as a marker of an acute infection. However, IgM can persist for several years, and Toxoplasma commercial IgM diagnostic test kits can yield a number of false-positive results. For these reasons, a chronic Toxoplasma infection can be erroneously classified as an acute infection, resulting in serious adverse consequences, especially in pregnant women, leading to emotional distress and unnecessary interventions, including termination of pregnancy. Interpretation of Toxoplasma serology at a reference laboratory can help differentiate a recently acquired infection from a chronic infection. Serological test results for 451 patients with positive Toxoplasma IgM and IgG test results obtained at nonreference laboratories (NRLs) that were referred to Palo Alto Medical Foundation Toxoplasma Serology Laboratory (PAMF-TSL) to determine whether the patient was acutely or chronically infected were retrospectively reviewed. PAMF-TSL results established that of the 451 patients, 335 (74%) had a chronic infection, 100 (22%) had an acute infection, and 7 (2%) were not infected, and for 9 (2%), results were indeterminate. Positive Toxoplasma IgM and IgG test results obtained at NRLs cannot accurately distinguish between acute and chronic infections. To do so, testing at reference laboratories is required, as mandated in 1997 in a letter from the Food and Drug Administration (FDA) to clinicians and laboratories in the United States.

  11. Significance of a Positive Toxoplasma Immunoglobulin M Test Result in the United States

    PubMed Central

    Gajurel, Kiran; Pomares, Christelle; Talucod, Jeanne; Press, Cynthia J.

    2015-01-01

    A positive Toxoplasma immunoglobulin M (IgM) result is often interpreted as a marker of an acute infection. However, IgM can persist for several years, and Toxoplasma commercial IgM diagnostic test kits can yield a number of false-positive results. For these reasons, a chronic Toxoplasma infection can be erroneously classified as an acute infection, resulting in serious adverse consequences, especially in pregnant women, leading to emotional distress and unnecessary interventions, including termination of pregnancy. Interpretation of Toxoplasma serology at a reference laboratory can help differentiate a recently acquired infection from a chronic infection. Serological test results for 451 patients with positive Toxoplasma IgM and IgG test results obtained at nonreference laboratories (NRLs) that were referred to Palo Alto Medical Foundation Toxoplasma Serology Laboratory (PAMF-TSL) to determine whether the patient was acutely or chronically infected were retrospectively reviewed. PAMF-TSL results established that of the 451 patients, 335 (74%) had a chronic infection, 100 (22%) had an acute infection, and 7 (2%) were not infected, and for 9 (2%), results were indeterminate. Positive Toxoplasma IgM and IgG test results obtained at NRLs cannot accurately distinguish between acute and chronic infections. To do so, testing at reference laboratories is required, as mandated in 1997 in a letter from the Food and Drug Administration (FDA) to clinicians and laboratories in the United States. PMID:26354818

  12. Standardization of disk diffusion test and its clinical significance for susceptibility testing of metronidazole against Helicobacter pylori.

    PubMed Central

    Xia, H; Keane, C T; Beattie, S; O'Morain, C A

    1994-01-01

    Susceptibilities of 121 clinical Helicobacter pylori strains to metronidazole were determined by both a 5-micrograms metronidazole disk diffusion test and a plate dilution method in duplicate and after different periods of incubation. The distribution of MICs of metronidazole against H. pylori among the strains was found to be bimodal. The diameters of inhibitory zones obtained by the disk diffusion test and the MICs obtained by the plate dilution method correlated well, especially after 4 days of incubation (r = 0.77). An inhibitory zone diameter of 20 mm was found to correspond to a MIC of 8 micrograms/ml and is recommended as a suitable zone for differentiating susceptibility and resistance with a 5-micrograms metronidazole disk. Three interpretive categories of susceptibility results were defined; strains with inhibitory zone diameters of more than 26 mm were defined as susceptible (MIC, < 4 micrograms/ml), strains with zone diameters of 20 to 26 mm were deemed intermediate (MIC, 4 to 8 micrograms/ml), and those with zone diameters of less than 20 mm were deemed resistant (MIC, > 8 micrograms/ml). Furthermore, 76 H. pylori-positive patients with duodenal ulcers or nonulcer dyspepsia were treated with a 1 week of triple therapy (colloidal bismuth subcitrate, metronidazole, and tetracycline). H. pylori strains were isolated before treatment from antral biopsies from those patients, and the metronidazole susceptibilities of the strains were determined by the disk diffusion test. H. pylori status was evaluated again 4 weeks after completion of treatment. The eradication rates for susceptible, intermediate, and resistant strains were 95.9% (47 of 49), 62.5% (5 of 8), and 52.6% (10 of 19), respectively. It is included that the 5-micrograms disk diffusion test is easy to perform and gives final results similar to those of the plate dilution method. The three interpretive categories of susceptibility may be of benefit for clinical choice of chemotherapy in eradicating

  13. 77 FR 30972 - Certain Polybrominated Diphenylethers; Significant New Use Rule and Test Rule; Extension of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-24

    ... Pollution Prevention and Toxics, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington... December 31, 2013, to conduct testing on their effects on health and the environment. The comment period is... Safety and Pollution Prevention. [FR Doc. 2012-12625 Filed 5-23-12; 8:45 am] BILLING CODE 6560-50-P...

  14. Finding of No Significant Impact and Environmental Assessment for Flight Test to the Edge of Space

    DTIC Science & Technology

    2008-12-01

    the Edge of Space Page 3-5 approximately 240 nautical miles wide as it crossed the California/ Oregon coast . The unmanned LEV 1 would cross the...cultural resources, environmental justice , geology and soils, hazardous waste/hazardous 5 materials, infrastructure, land use, natural resources, noise...altitudes (up to 264,000 feet above mean sea level [MSL]) over the western United States and off the west coast of the United States. These flight tests

  15. Minute Impurities Contribute Significantly to Olfactory Receptor Ligand Studies: Tales from Testing the Vibration Theory

    PubMed Central

    2017-01-01

    Several studies have attempted to test the vibrational hypothesis of odorant receptor activation in behavioral and physiological studies using deuterated compounds as odorants. The results have been mixed. Here, we attempted to test how deuterated compounds activate odorant receptors using calcium imaging of the fruit fly antennal lobe. We found specific activation of one area of the antennal lobe corresponding to inputs from a specific receptor. However, upon more detailed analysis, we discovered that an impurity of 0.0006% ethyl acetate in a chemical sample of benzaldehyde-d5 was entirely responsible for a sizable odorant-evoked response in Drosophila melanogaster olfactory receptor cells expressing dOr42b. Without gas chromatographic purification within the experimental setup, this impurity would have created a difference in the responses of deuterated and nondeuterated benzaldehyde, suggesting that dOr42b be a vibration sensitive receptor, which we show here not to be the case. Our results point to a broad problem in the literature on use of non-GC-pure compounds to test receptor selectivity, and we suggest how the limitations can be overcome in future studies. PMID:28670618

  16. Analysis of residuals in contingency tables: another nail in the coffin of conditional approaches to significance testing.

    PubMed

    García-Pérez, Miguel A; Núñez-Antón, Vicente; Alcalá-Quintana, Rocío

    2015-03-01

    Omnibus tests of significance in contingency tables use statistics of the chi-square type. When the null is rejected, residual analyses are conducted to identify cells in which observed frequencies differ significantly from expected frequencies. Residual analyses are thus conditioned on a significant omnibus test. Conditional approaches have been shown to substantially alter type I error rates in cases involving t tests conditional on the results of a test of equality of variances, or tests of regression coefficients conditional on the results of tests of heteroscedasticity. We show that residual analyses conditional on a significant omnibus test are also affected by this problem, yielding type I error rates that can be up to 6 times larger than nominal rates, depending on the size of the table and the form of the marginal distributions. We explored several unconditional approaches in search for a method that maintains the nominal type I error rate and found out that a bootstrap correction for multiple testing achieved this goal. The validity of this approach is documented for two-way contingency tables in the contexts of tests of independence, tests of homogeneity, and fitting psychometric functions. Computer code in MATLAB and R to conduct these analyses is provided as Supplementary Material.

  17. Analysis of pumping tests: Significance of well diameter, partial penetration, and noise

    USGS Publications Warehouse

    Heidari, M.; Ghiassi, K.; Mehnert, E.

    1999-01-01

    The nonlinear least squares (NLS) method was applied to pumping and recovery aquifer test data in confined and unconfined aquifers with finite diameter and partially penetrating pumping wells, and with partially penetrating piezometers or observation wells. It was demonstrated that noiseless and moderately noisy drawdown data from observation points located less than two saturated thicknesses of the aquifer from the pumping well produced an exact or acceptable set of parameters when the diameter of the pumping well was included in the analysis. The accuracy of the estimated parameters, particularly that of specific storage, decreased with increases in the noise level in the observed drawdown data. With consideration of the well radii, the noiseless drawdown data from the pumping well in an unconfined aquifer produced good estimates of horizontal and vertical hydraulic conductivities and specific yield, but the estimated specific storage was unacceptable. When noisy data from the pumping well were used, an acceptable set of parameters was not obtained. Further experiments with noisy drawdown data in an unconfined aquifer revealed that when the well diameter was included in the analysis, hydraulic conductivity, specific yield and vertical hydraulic conductivity may be estimated rather effectively from piezometers located over a range of distances from the pumping well. Estimation of specific storage became less reliable for piezemeters located at distances greater than the initial saturated thickness of the aquifer. Application of the NLS to field pumping and recovery data from a confined aquifer showed that the estimated parameters from the two tests were in good agreement only when the well diameter was included in the analysis. Without consideration of well radii, the estimated values of hydraulic conductivity from the pumping and recovery tests were off by a factor of four.The nonlinear least squares method was applied to pumping and recovery aquifer test data in

  18. Strategies for Testing Statistical and Practical Significance in Detecting DIF with Logistic Regression Models

    ERIC Educational Resources Information Center

    Fidalgo, Angel M.; Alavi, Seyed Mohammad; Amirian, Seyed Mohammad Reza

    2014-01-01

    This study examines three controversial aspects in differential item functioning (DIF) detection by logistic regression (LR) models: first, the relative effectiveness of different analytical strategies for detecting DIF; second, the suitability of the Wald statistic for determining the statistical significance of the parameters of interest; and…

  19. Strategies for Testing Statistical and Practical Significance in Detecting DIF with Logistic Regression Models

    ERIC Educational Resources Information Center

    Fidalgo, Angel M.; Alavi, Seyed Mohammad; Amirian, Seyed Mohammad Reza

    2014-01-01

    This study examines three controversial aspects in differential item functioning (DIF) detection by logistic regression (LR) models: first, the relative effectiveness of different analytical strategies for detecting DIF; second, the suitability of the Wald statistic for determining the statistical significance of the parameters of interest; and…

  20. Adjusting a Significance Test for Clustering in Designs with Two Levels of Nesting

    ERIC Educational Resources Information Center

    Hedges, Larry V.

    2009-01-01

    A common mistake in analysis of cluster randomized experiments is to ignore the effect of clustering and analyze the data as if each treatment group were a simple random sample. This typically leads to an overstatement of the precision of results and anticonservative conclusions about precision and statistical significance of treatment effects.…

  1. Cryptococcal antigen test revisited: significance for cryptococcal meningitis therapy monitoring in a tertiary chinese hospital.

    PubMed

    Lu, Hongzhou; Zhou, Yingjie; Yin, Youkuan; Pan, Xiaozhang; Weng, Xinhua

    2005-06-01

    For a total of 29 non-human immunodeficiency virus 1 cryptococcal meningitis cases, titer changes in the latex agglutination test before and after therapy were reviewed along with clinical manifestations, laboratory findings, and therapy regimens. The cryptococcal antigen titer decreased for every case after therapy and was correlated to fungal clearance as defined by fungus smear and/or culture. However, cryptococcal antigen can remain at low titers for long periods of time after therapy, even when fungus smears and/or cultures become negative.

  2. Combination antimicrobial susceptibility testing of Burkholderia cepacia complex: significance of species.

    PubMed

    Abbott, Felicity K; Milne, Kathleen E N; Stead, David A; Gould, Ian M

    2016-11-01

    The Burkholderia cepacia complex (Bcc) is notorious for the life-threatening pulmonary infections it causes in patients with cystic fibrosis. The multidrug-resistant nature of Bcc and differing infective Bcc species make the design of appropriate treatment regimens challenging. Previous synergy studies have failed to take account of the species of Bcc isolates. Etest methodology was used to facilitate minimum inhibitory concentration (MIC) and antimicrobial combination testing on 258 isolates of Bcc, identified to species level by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). The most active antimicrobials were trimethoprim/sulphamethoxazole, doxycycline and minocycline (52.5%, 46.4% and 45.9% of isolates susceptible, respectively). Synergy was observed in 9.2% of the 1799 combinations tested; the most common synergistic combinations were tobramycin + ceftazidime, meropenem + tobramycin and levofloxacin + piperacillin/tazobactam (35.4%, 32.3% and 22.2% synergy, respectively). Antimicrobial susceptibility analysis revealed differences between Burkholderia cenocepacia and Burkholderia multivorans. Disparity in clinical outcome during infection with these two micro-organisms necessitates further investigation into the clinical outcomes of treatment regimens in light of species identification and in vitro antimicrobial susceptibility studies.

  3. Patch testing with budesonide in serial dilutions: the significance of dose, occlusion time and reading time.

    PubMed

    Isaksson, M; Bruze, M; Goossens, A; Lepoittevin, J P

    1999-01-01

    Budesonide is advocated as a marker molecule for corticosteroid contact allergy. When patch testing corticosteroids, one must consider their sensitizing potential but also their anti-inflammatory properties, as well as the possibility of different time courses for such properties. The dose-response relationship for budesonide was therefore investigated with regard to dose, occlusion time, and reading time. 10 patients were patch tested with budesonide in ethanol in serial dilutions from 2.0% down to 0.0002% with occlusion times of 48, 24, and 5 h. Readings were on D2, D4, and D7. The 48-h occlusion picked up most positive reactors, 8/10. The D4 reading (48-h occlusion) detected most positive reactors, 8/10, and here 0.002% picked up most contact allergies. Late readings favoured high concentrations. The "edge effect" was noted for several concentrations at early readings. Due to the individual corticosteroid reactivity, the dose-response relationship and the time courses of the elicitation and the anti-inflammatory capacity, several features may be explained, i.e., that lower concentrations may detect budesonide allergy better at early readings, that patients with an "edge reaction" can have positive reactions to lower concentrations.

  4. Frequency and Prognostic Significance of Abnormal Liver Function Tests in Patients With Cardiogenic Shock.

    PubMed

    Jäntti, Toni; Tarvasmäki, Tuukka; Harjola, Veli-Pekka; Parissis, John; Pulkki, Kari; Sionis, Alessandro; Silva-Cardoso, Jose; Køber, Lars; Banaszewski, Marek; Spinar, Jindrich; Fuhrmann, Valentin; Tolonen, Jukka; Carubelli, Valentina; diSomma, Salvatore; Mebazaa, Alexandre; Lassus, Johan

    2017-10-01

    Cardiogenic shock (CS) is a cardiac emergency often leading to multiple organ failure and death. Assessing organ dysfunction and appropriate risk stratification are central for the optimal management of these patients. The purpose of this study was to assess the prevalence of abnormal liver function tests (LFTs), as well as early changes of LFTs and their impact on outcome in CS. We measured LFTs in 178 patients in CS from serial blood samples taken at 0 hours, 12 hours, and 24 hours. The associations of LFT abnormalities and their early changes with all-cause 90-day mortality were estimated using Fisher's exact test and Cox proportional hazards regression analysis. Baseline alanine aminotransferase (ALT) was abnormal in 58% of the patients, more frequently in nonsurvivors. Abnormalities in other LFTs analyzed (alkaline phosphatase, gamma-glutamyl transferase, and total bilirubin) were not associated with short-term mortality. An increase in ALT of >20% within 24 hours (ΔALT>+20%) was observed in 24% of patients. ΔALT>+20% was associated with a more than 2-fold increase in mortality compared with those with stable or decreasing ALT (70% and 28%, p <0.001). Multivariable regression analysis showed that ΔALT>+20% was associated with increased 90-day mortality independent of other known risk factors. In conclusion, an increase in ALT in the initial phase was seen in 1/4 of patients in CS and was independently associated with 90-day mortality. This finding suggests that serial ALT measurements should be incorporated in the clinical assessment of patients in CS. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Direct transfer of HRPII-magnetic bead complexes to malaria rapid diagnostic tests significantly improves test sensitivity.

    PubMed

    Ricks, Keersten M; Adams, Nicholas M; Scherr, Thomas F; Haselton, Frederick R; Wright, David W

    2016-08-05

    The characteristic ease of use, rapid time to result, and low cost of malaria rapid diagnostic tests (RDTs) promote their widespread use at the point-of-care for malaria detection and surveillance. However, in many settings, the success of malaria elimination campaigns depends on point-of-care diagnostics with greater sensitivity than currently available RDTs. To address this need, a sample preparation method was developed to deliver more biomarkers onto a malaria RDT by concentrating the biomarker from blood sample volumes that are too large to be directly applied to a lateral flow strip. In this design, Ni-NTA-functionalized magnetic beads captured the Plasmodium falciparum biomarker HRPII from a P. falciparum D6 culture spiked blood sample. This transfer of magnetic beads to the RDT was facilitated by an inexpensive 3D-printed apparatus that aligned the sample tube with the sample deposition pad and a magnet beneath the RDT. Biomarkers were released from the bead surface onto the lateral flow strip using imidazole-spiked running buffer. Kinetics of HRPII binding to the Ni-NTA beads as a function of blood sample volume were explored prior to determining the effect of the proposed method on the limit of detection of Paracheck RDTs. More than 80 % of HRPII biomarkers were extracted from blood sample volumes ranging from 25 to 250 µL. The time required to reach 80 % binding ranged from 5 to 60 min, depending on sample volume. Using 250 μL of blood and a 30-min biomarker binding time, the limit of detection of the Paracheck Pf RDT brand was improved by 21-fold, resulting in a limit of detection below 1 parasite/μL. This approach has the sensitivity and simplicity required to assist in malaria elimination campaigns in settings with limited access to clinical and laboratory resources.

  6. Significance testing for quasi-periodic pulsations in solar and stellar flares

    NASA Astrophysics Data System (ADS)

    Pugh, C. E.; Broomhall, A.-M.; Nakariakov, V. M.

    2017-06-01

    The robust detection of quasi-periodic pulsations (QPPs) in solar and stellar flares has been the topic of recent debate. In light of this, we have adapted a method described by Vaughan (2005, A&A, 431, 391) to aid with the search for QPPs in flare time series data. The method identifies statistically significant periodic signals in power spectra, and properly accounts for red noise as well as the uncertainties associated with the data. We show how the method can be further developed to be used with rebinned power spectra, allowing us to detect QPPs whose signal is spread over more than one frequency bin. An advantage of these methods is that there is no need to detrend the data prior to creating the power spectrum. Examples are given where the methods have been applied to synthetic data, as well as real flare time series data with candidate QPPs from the Nobeyama Radioheliograph. These show that, despite the transient nature of QPPs, peaks corresponding to the QPPs can be seen at a significant level in the power spectrum without any form of detrending or other processing of the original time series data, providing the background trends are not too steep.

  7. Floral signposts: testing the significance of visual 'nectar guides' for pollinator behaviour and plant fitness.

    PubMed

    Hansen, Dennis M; Van der Niet, Timotheüs; Johnson, Steven D

    2012-02-22

    Nectar guides, contrasting patterns on flowers that supposedly direct pollinators towards a concealed nectar reward, are taxonomically widespread. However, there have been few studies of their functional significance and effects on plant fitness. Most previous studies focused on pollinator behaviour and used artificial flowers in laboratory settings. We experimentally investigated the role of putative nectar guides in a natural system: the South African iris Lapeirousia oreogena, whose flowers have a clearly visible pattern of six white arrow-markings pointing towards the narrow entrance of the long corolla tube, and its sole pollinator, a long-proboscid nemestrinid fly. We painted over none, some or all of the white arrow-markings with ink that matched the colour of the corolla background. Although arrow-marking removal had little effect on the approaches by flies to flowers from a distance, it dramatically reduced the likelihood of proboscis insertion. Export of pollen dye analogue (an estimate of male fitness) was reduced to almost zero in flowers from which all nectar guides had been removed, and fruit set (a measure of female fitness) was also significantly reduced. Our results confirm that the markings on L. oreogena flowers serve as nectar guides and suggest that they are under strong selective maintenance through both male and female fitness components in this pollination system.

  8. Testing reanalysis data sets in Antarctica: Trends, persistence properties, and trend significance

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Zhou, Dong; Bunde, Armin; Havlin, Shlomo

    2016-11-01

    The reanalysis data sets provide important sources for investigating the climate in Antarctica where stations are sparse. In this paper, we compare the 2 m near-surface temperature data from five major reanalysis data sets with observational Antarctic stations data over the last 36 years: (i) the National Centers for Environmental Prediction and the National Center for Atmospheric Research Reanalysis (NCEP1), (ii) NCEP-DOE Reanalysis 2 (NCEP2), (iii) the European Centre for Medium-Range Weather Forecasts Interim Reanalysis (ERA-Interim), (iv) the Japanese 55 year Reanalysis (JRA-55), and (v) the National Aeronautics and Space Administration Modern-Era Retrospective-analysis for Research and Applications. In our assessment, we compare (a) the annual and seasonal trends obtained by linear regression analysis, (b) the standard deviation around the annual trends, (c) the detrended lag-1-autocorrelation C(1), (d) the Hurst exponent α that characterizes the long-term memory in a record, and (e) the significance levels of the warming/cooling trends. We find that all five reanalysis data sets are able to reproduce quite well the long-term memory in the instrumental data. In contrast, C(1), which is needed as input for the conventional significance analysis, shows fully erratic behavior. The observational warming/cooling trends in East and West Antarctica are not reproduced well by all reanalysis data sets, in particular, NCEP1, NCEP2, and JRA-55 show spurious warming trends in many parts of East Antarctica, even in those parts where cooling has been observed. In contrast, the standard deviation around the trends is quite well reproduced by all reanalysis data sets. In the peninsula where the station density is quite high, the performance of the reanalysis data is considerably better. It is remarkable that all reanalysis data sets as well as the observational data show (under the assumption of a long-term persistent process) that in the considered time period since 1979

  9. Significance of repeated exercise testing with thallium-201 scanning in asymptomatic diabetic males

    SciTech Connect

    Rubler, S.; Fisher, V.J.

    1985-12-01

    This study was conducted with asymptomatic middle-aged male subjects with diabetes mellitus to detect latent cardiac disease using noninvasive techniques. One group of 38 diabetic males (mean age 50.5 +/- 10.2 years) and a group of 15 normal males (mean age 46.9 +/- 10.0 years) participated in the initial trial; 13 diabetic patients and 7 control subjects were restudied 1-2 years later. Maximal treadmill exercise with a Bruce protocol and myocardial scintigraphy with thallium-201(201Tl) were used. Diabetic subjects on initial examination and retesting achieved a lower maximal heart rate and duration of exercise than control subjects. Abnormal electrocardiographic changes, thallium defects, or both were observed in 23/38 diabetic males (60.5%) on the first study and only one 65-year-old control subject had such findings. On retesting, the control subjects had no abnormalities while 76.9% of diabetic subjects had either 201Tl defects or ECG changes. We conclude that despite the fact that none of diabetic males had any clinical evidence or symptoms of heart disease, this high-risk group demonstrated abnormalities on exercise testing that merit careful subsequent evaluation and followup and could be an effective method of detecting early cardiac disease.

  10. Significance of HbA1c Test in Diagnosis and Prognosis of Diabetic Patients

    PubMed Central

    Sherwani, Shariq I.; Khan, Haseeb A.; Ekhzaimy, Aishah; Masood, Afshan; Sakharkar, Meena K.

    2016-01-01

    Diabetes is a global endemic with rapidly increasing prevalence in both developing and developed countries. The American Diabetes Association has recommended glycated hemoglobin (HbA1c) as a possible substitute to fasting blood glucose for diagnosis of diabetes. HbA1c is an important indicator of long-term glycemic control with the ability to reflect the cumulative glycemic history of the preceding two to three months. HbA1c not only provides a reliable measure of chronic hyperglycemia but also correlates well with the risk of long-term diabetes complications. Elevated HbA1c has also been regarded as an independent risk factor for coronary heart disease and stroke in subjects with or without diabetes. The valuable information provided by a single HbA1c test has rendered it as a reliable biomarker for the diagnosis and prognosis of diabetes. This review highlights the role of HbA1c in diagnosis and prognosis of diabetes patients. PMID:27398023

  11. Bootstrap tests of significance and the case for humanlike skeletal-size dimorphism in Australopithecus afarensis.

    PubMed

    Scott, Jeremiah E; Stroik, Laura K

    2006-10-01

    Most estimates of sexual size dimorphism in Australopithecus afarensis indicate that this early hominin was more dimorphic than modern humans. In contrast, a recent study reported that size variation in A. afarensis, as represented by postcranial remains from Hadar and Maka, Ethiopia, is statistically most similar to that of modern humans, indicating a humanlike level of sexual dimorphism. Here, we evaluate the evidence for humanlike dimorphism in A. afarensis. We argue that statistical support for this claim is not as robust as has been asserted for the following reasons: (1) the analysis from which the claim was derived does not distinguish the A. afarensis sample from either the human or chimpanzee samples; (2) for some of the comparisons made, the A. afarensis sample cannot be distinguished from the Gorilla sample using two-tailed tests; and (3) the A. afarensis postcranial sample used in the analysis may contain more male than female specimens, which precludes a straightforward interpretation of the statistical results. Thus, support for humanlike dimorphism is equivocal, and a greater level of dimorphism cannot be ruled out.

  12. A procedure for testing the significance of orbital tuning of the martian polar layered deposits

    NASA Astrophysics Data System (ADS)

    Sori, Michael M.; Perron, J. Taylor; Huybers, Peter; Aharonson, Oded

    2014-06-01

    Layered deposits of dusty ice in the martian polar caps have been hypothesized to record climate changes driven by orbitally induced variations in the distribution of incoming solar radiation. Attempts to identify such an orbital signal by tuning a stratigraphic sequence of polar layered deposits (PLDs) to match an assumed forcing introduce a risk of identifying spurious matches between unrelated records. We present an approach for evaluating the significance of matches obtained by orbital tuning, and investigate the utility of this approach for identifying orbital signals in the Mars PLDs. Using a set of simple models for ice and dust accumulation driven by insolation, we generate synthetic PLD stratigraphic sequences with nonlinear time-depth relationships. We then use a dynamic time warping algorithm to attempt to identify an orbital signal in the modeled sequences, and apply a Monte Carlo procedure to determine whether this match is significantly better than a match to a random sequence that contains no orbital signal. For simple deposition mechanisms in which dust deposition rate is constant and ice deposition rate varies linearly with insolation, we find that an orbital signal can be confidently identified if at least 10% of the accumulation time interval is preserved as strata. Addition of noise to our models raises this minimum preservation requirement, and we expect that more complex deposition functions would generally also make identification more difficult. In light of these results, we consider the prospects for identifying an orbital signal in the actual PLD stratigraphy, and conclude that this is feasible even with a strongly nonlinear relationship between stratigraphic depth and time, provided that a sufficient fraction of time is preserved in the record and that ice and dust deposition rates vary predictably with insolation. Independent age constraints from other techniques may be necessary, for example, if an insufficient amount of time is

  13. SmileFinder: a resampling-based approach to evaluate signatures of selection from genome-wide sets of matching allele frequency data in two or more diploid populations.

    PubMed

    Guiblet, Wilfried M; Zhao, Kai; O'Brien, Stephen J; Massey, Steven E; Roca, Alfred L; Oleksyk, Taras K

    2015-01-01

    Adaptive alleles may rise in frequency as a consequence of positive selection, creating a pattern of decreased variation in the neighboring loci, known as a selective sweep. When the region containing this pattern is compared to another population with no history of selection, a rise in variance of allele frequencies between populations is observed. One challenge presented by large genome-wide datasets is the ability to differentiate between patterns that are remnants of natural selection from those expected to arise at random and/or as a consequence of selectively neutral demographic forces acting in the population. SmileFinder is a simple program that looks for diversity and divergence patterns consistent with selection sweeps by evaluating allele frequencies in windows, including neighboring loci from two or more populations of a diploid species against the genome-wide neutral expectation. The program calculates the mean of heterozygosity and FST in a set of sliding windows of incrementally increasing sizes, and then builds a resampled distribution (the baseline) of random multi-locus sets matched to the sizes of sliding windows, using an unrestricted sampling. Percentiles of the values in the sliding windows are derived from the superimposed resampled distribution. The resampling can easily be scaled from 1 K to 100 M; the higher the number, the more precise the percentiles ascribed to the extreme observed values. The output from SmileFinder can be used to plot percentile values to look for population diversity and divergence patterns that may suggest past actions of positive selection along chromosome maps, and to compare lists of suspected candidate genes under random gene sets to test for the overrepresentation of these patterns among gene categories. Both applications of the algorithm have already been used in published studies. Here we present a publicly available, open source program that will serve as a useful tool for preliminary scans of selection

  14. [Physiological significance and interpretation of plasma lactate concentration and pH in clinical exercise testing].

    PubMed

    Péronnet, F; Aguilaniu, B

    2014-06-01

    According to a widely accepted model, based on the theory of the anaerobic threshold (AT), the increase in plasma lactate concentration which develops after the first ventilatory threshold (VT1, considered as an AT) is due to compensation for insufficient aerobic metabolism by anaerobic glycolysis, with accumulation of lactic acid resulting in a decrease in pH. Bicarbonate is the main buffer of protons (>90%) producing non-metabolic CO2 in muscle and thus increasing the CO2 flux to the lungs. This phenomenon, along with the low pH, triggers hyperventilation. Because of this model, great importance has been placed on plasma lactate and pH. We argue that this importance is excessive and these variables should be used with caution in the interpretation of clinical exercise testing, because the model based on AT is not valid: there is no aerobic failure above VT1 and, thus, there is no evidence of an AT; the increase in plasma lactate does not reflect anaerobiosis but is the marker of the increase in the error signal needed for the stimulation of mitochondrial respiration; bicarbonate is not the main buffer during exercise (these are proteins and phosphocreatine breakdown in the muscle; hemoglobin in the blood); non-metabolic CO2 is not produced in the muscle but in the lung because of the low pH and hyperventilation (the control of which remains unknown); and the flux of CO2 to the lung does not increase at faster rate after than before VT1.

  15. A test of the significance of intermolecular vibrational coupling in isotopic fractionation

    NASA Astrophysics Data System (ADS)

    Herman, Michael F.; Currier, Robert P.; Peery, Travis B.; Clegg, Samuel M.

    2017-09-01

    Intermolecular coupling of dipole moments is studied for a model system consisting of two diatomic molecules (AB monomers) arranged co-linearly and which can form non-covalently bound dimers. The dipolar coupling is a function of the bond length in each molecule as well as of the distance between the centers-of-mass of the two molecules. The calculations show that intermolecular coupling of the vibrations results in an isotope-dependent modification of the AB-AB intermolecular potential. This in turn alters the energies of the low-lying bound states of the dimers, producing isotope-dependent changes in the AB-AB dimer partition function. Explicit inclusion of intermolecular vibrational coupling then changes the predicted gas-dimer isotopic fractionation. In addition, a mass dependence in the intermolecular potential can also result in changes in the number of bound dimer states in an equilibrium mixture. This in turn leads to a significant dimer population shift in the model monomer-dimer equilibrium system considered here. The results suggest that intermolecular coupling terms should be considered when probing the origins of isotopic fractionation.

  16. Significance tests on the output power of a thermally driven rotary nanomotor

    NASA Astrophysics Data System (ADS)

    Yang, Likui; Cai, Kun; Shi, Jiao; Qin, Qing H.

    2017-05-01

    Many factors can have a significant influence on the output power of a thermally driven rotary nanomotor made of carbon nanotubes (CNTs). Making use of a computational molecular dynamics approach, we evaluate for the first time the output power of a nanomotor, considering some of the main factors including temperature, the diameter of the rotor and the number of IRD atoms (N) on the stator. When applying extra-resistant torque to the rotor to let the stable value of the rotational frequency of the rotor fluctuate near zero, the value of the resistant torque can be considered as the output power of the rotor. The effects of these factors on the output power of a motor are roughly predicted via a fitting approach. Using stepwise regression analysis, we discover that N has the greatest influence on the output power. The second and the third main factors that affect the output power of a nanomotor are the diameter of the rotor, and the interaction between N and the diameter, respectively. To improve the output power of a nanomotor, one can place more IRD atoms in the system and/or employ CNTs with larger diameters.

  17. A test of the significance of intermolecular vibrational coupling in isotopic fractionation

    DOE PAGES

    Herman, Michael F.; Currier, Robert P.; Peery, Travis B.; ...

    2017-07-15

    Intermolecular coupling of dipole moments is studied for a model system consisting of two diatomic molecules (AB monomers) arranged co-linearly and which can form non-covalently bound dimers. The dipolar coupling is a function of the bond length in each molecule as well as of the distance between the centers-of-mass of the two molecules. The calculations show that intermolecular coupling of the vibrations results in an isotope-dependent modification of the AB-AB intermolecular potential. This in turn alters the energies of the low-lying bound states of the dimers, producing isotope-dependent changes in the AB-AB dimer partition function. Explicit inclusion of intermolecular vibrationalmore » coupling then changes the predicted gas-dimer isotopic fractionation. In addition, a mass dependence in the intermolecular potential can also result in changes in the number of bound dimer states in an equilibrium mixture. This in turn leads to a significant dimer population shift in the model monomer-dimer equilibrium system considered here. Finally, the results suggest that intermolecular coupling terms should be considered when probing the origins of isotopic fractionation.« less

  18. On the Relationship between the Johnson-Neyman Region of Significance and Statistical Tests of Parallel Within-Group Regressions.

    ERIC Educational Resources Information Center

    Rogosa, David

    1981-01-01

    The form of the Johnson-Neyman region of significance is shown to be determined by the statistic for testing the null hypothesis that the population within-group regressions are parallel. Results are obtained for both simultaneous and nonsimultaneous regions of significance. (Author)

  19. Evolutionary significance of phenotypic accommodation in novel environments: an empirical test of the Baldwin effect

    PubMed Central

    Badyaev, Alexander V.

    2009-01-01

    When faced with changing environments, organisms rapidly mount physiological and behavioural responses, accommodating new environmental inputs in their functioning. The ubiquity of this process contrasts with our ignorance of its evolutionary significance: whereas within-generation accommodation of novel external inputs has clear fitness consequences, current evolutionary theory cannot easily link functional importance and inheritance of novel accommodations. One hundred and twelve years ago, J. M. Baldwin, H. F. Osborn and C. L. Morgan proposed a process (later termed the Baldwin effect) by which non-heritable developmental accommodation of novel inputs, which makes an organism fit in its current environment, can become internalized in a lineage and affect the course of evolution. The defining features of this process are initial overproduction of random (with respect to fitness) developmental variation, followed by within-generation accommodation of a subset of this variation by developmental or functional systems (‘organic selection’), ensuring the organism's fit and survival. Subsequent natural selection sorts among resultant developmental variants, which, if recurrent and consistently favoured, can be inherited when existing genetic variance includes developmental components of individual modifications or when the ability to accommodate novel inputs is itself heritable. Here, I show that this process is consistent with the origin of novel adaptations during colonization of North America by the house finch. The induction of developmental variation by novel environments of this species's expanding range was followed by homeostatic channelling, phenotypic accommodation and directional cross-generational transfer of a subset of induced developmental outcomes favoured by natural selection. These results emphasize three principal points. First, contemporary novel adaptations result mostly from reorganization of existing structures that shape newly expressed

  20. [The significance and place of HBsAg neutralization test in the diagnosis and algorithm of hepatitis B infection].

    PubMed

    Aytaç, Özlem; Toyran, Alparslan; Aksoy, Altan

    2017-04-01

    The diagnosis of hepatitis B virus infection is evaluated serologically, virologically, biochemically, and with histologic liver indicators. The aim of this study was to investigate the place and significance of the HBsAg neutralization test in the diagnostic algorithm for hepatitis Binfection. From the venous blood samples sent to Ankara Numune Education and Research Hospital Medical Microbiology Laboratory between September 2014 and May 2016 for HBsAg test, serum samples regarded each patient as reactive (≥ 0.9 S\\CO) , 9 ≤ S ≤ CO ≤ 30) were studied twice. A total of 105 samples which were reactive in both analyses were included in the study. After the evaluation of these samples by neutralization confirmation test, which is routinely performed in our laboratory, the samples were stored under optimal conditions and studied for HBV DNA with the real-time PCR and for HBeAg, anti-HBeAg, anti-HBc IgM, and anti-HBc total antibody assays by ELISA. The 105 samples, in which HBsAg was detected, were analyzed with the neutralization test. The presence of HBsAg was confirmed by neutralization test in 67 of 105 samples (63.8%), and of these patients, two patients (2.3%) had negative HBV DNA and anti-HBc total antibody test (false positive neutralization test). Of the 105 samples included in the study, the anti-HBc total antibody test was positive in 78 patients (74.3%). However, out of these 78 patients who were positive for the anti-HBc total antibody test, there were 13 patients (16.7%) with negative neutralization and HBV DNA test results (false positive anti-HBc total antibody test). The HBV DNA positivity was detected significantly lower in samples with HBsAg level ≤ 5 S/CO compared to the samples with HBsAg level > 5 S/CO (p= 0.020). Also, if the unit price of the neutralization test used in our study was considered, the cost was 17,00 TL while the unit price of HBV DNA test was 55,00 TL. Utilization of the neutralization test instead of HBV DNA test

  1. Methods for significance testing of categorical covariates in logistic regression models after multiple imputation: power and applicability analysis.

    PubMed

    Eekhout, Iris; van de Wiel, Mark A; Heymans, Martijn W

    2017-08-22

    Multiple imputation is a recommended method to handle missing data. For significance testing after multiple imputation, Rubin's Rules (RR) are easily applied to pool parameter estimates. In a logistic regression model, to consider whether a categorical covariate with more than two levels significantly contributes to the model, different methods are available. For example pooling chi-square tests with multiple degrees of freedom, pooling likelihood ratio test statistics, and pooling based on the covariance matrix of the regression model. These methods are more complex than RR and are not available in all mainstream statistical software packages. In addition, they do not always obtain optimal power levels. We argue that the median of the p-values from the overall significance tests from the analyses on the imputed datasets can be used as an alternative pooling rule for categorical variables. The aim of the current study is to compare different methods to test a categorical variable for significance after multiple imputation on applicability and power. In a large simulation study, we demonstrated the control of the type I error and power levels of different pooling methods for categorical variables. This simulation study showed that for non-significant categorical covariates the type I error is controlled and the statistical power of the median pooling rule was at least equal to current multiple parameter tests. An empirical data example showed similar results. It can therefore be concluded that using the median of the p-values from the imputed data analyses is an attractive and easy to use alternative method for significance testing of categorical variables.

  2. Test of significant toxicity: a statistical application for assessing whether an effluent or site water is truly toxic.

    PubMed

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

    2011-05-01

    The U.S. Environmental Protection Agency (U.S. EPA) and state agencies implement the Clean Water Act, in part, by evaluating the toxicity of effluent and surface water samples. A common goal for both regulatory authorities and permittees is confidence in an individual test result (e.g., no-observed-effect concentration [NOEC], pass/fail, 25% effective concentration [EC25]), which is used to make regulatory decisions, such as reasonable potential determinations, permit compliance, and watershed assessments. This paper discusses an additional statistical approach (test of significant toxicity [TST]), based on bioequivalence hypothesis testing, or, more appropriately, test of noninferiority, which examines whether there is a nontoxic effect at a single concentration of concern compared with a control. Unlike the traditional hypothesis testing approach in whole effluent toxicity (WET) testing, TST is designed to incorporate explicitly both α and β error rates at levels of toxicity that are unacceptable and acceptable, given routine laboratory test performance for a given test method. Regulatory management decisions are used to identify unacceptable toxicity levels for acute and chronic tests, and the null hypothesis is constructed such that test power is associated with the ability to declare correctly a truly nontoxic sample as acceptable. This approach provides a positive incentive to generate high-quality WET data to make informed decisions regarding regulatory decisions. This paper illustrates how α and β error rates were established for specific test method designs and tests the TST approach using both simulation analyses and actual WET data. In general, those WET test endpoints having higher routine (e.g., 50th percentile) within-test control variation, on average, have higher method-specific α values (type I error rate), to maintain a desired type II error rate. This paper delineates the technical underpinnings of this approach and demonstrates the benefits

  3. Significance Testing Without Truth

    DTIC Science & Technology

    2012-07-27

    following structure: Section 2 very briefly discusses Bayesian-frequentist hybrids, referring for details to the definitive work of Gelman (2003). Section 3...However, there exist Bayesian-frequentist hybrids known as “Bayesian P-values”; Gelman (2003) sets forth a particularly appealing formulation. Bayesian P...Jianqing Fan, Jiayang Gao, Andrew Gelman , Leslie Greengard, Peter W. Jones, Deborah Mayo, Peter Mc- Cullagh, Michael O’Neil, Ron Peled, William H. Press

  4. Modifications to the AOAC use-dilution test for quaternary ammonium compound-based disinfectants that significantly improve method reliability.

    PubMed

    Arlea, Crystal; King, Sharon; Bennie, Barbara; Kemp, Kere; Mertz, Erin; Staub, Richard

    2008-01-01

    The AOAC use-dilution test (UDT) for bactericidal disinfectant efficacy (Method 964.02) has often been criticized for its extreme variability in test results, particularly for quaternary ammonium compound (QAC)-based disinfectants against Pseudomonas aeruginosa. While efforts are under way to develop a new and better test method for hospital disinfectant products that is globally acceptable, U.S. manufacturers and formulators of QAC products must continue in the interim to measure their product performance against the current UDT method. Therefore, continued variability in the UDT places an unnecessary and unfair burden on U.S. QAC product manufacturers to ensure that their products perform against an, at best, unreliable test method. This article reports on evaluations that were conducted to attempt to identify key sources of UDT method variability and to find ways to mitigate their impact on test outcomes for the method. The results of testing across 4 laboratories, involving over 6015 carriers, determined that operator error was a key factor in test variability. This variability was found to be significantly minimized by the inclusion of a simple culture dilution step. The findings from this study suggest possible refinements to the current AOAC UDT method that would serve to improve the overall ruggedness and reliability of the method and to optimize recovery of cells from the carrier surface, thereby further improving the accuracy and reproducibility of counts and test outcomes until such time as a replacement method is implemented.

  5. Significant cost savings achieved by in-sourcing urine drug testing for monitoring medication compliance in pain management.

    PubMed

    Melanson, Stacy E F; Tanasijevic, Milenko J; Snyder, Marion L; Darragh, Alicia; Quade, Cathleen; Jarolim, Petr

    2013-06-25

    Reference laboratory testing can represent a significant component of the laboratory budget. Therefore, most laboratories continually reassess the feasibility of in-sourcing various tests. We describe the transfer of urine drug testing performed for monitoring medication compliance in pain management from a reference laboratory into an academic clinical laboratory. The process of implementing of both screening immunoassays and confirmatory LC-MS/MS testing and the associated cost savings is outlined. The initial proposal for in-sourcing this testing, which included the tests to be in-sourced, resources required, estimated cost savings and timeline for implementation, was approved in January 2009. All proposed testing was implemented by March 2011. Keys to the successful implementation included budgeting adequate resources and developing a realistic timeline, incorporating the changes with the highest budget impact first. We were able to in-source testing in 27 months and save the laboratory approximately $1 million in the first 3 year. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Blood coagulation tests in toxicological studies--review of methods and their significance for drug safety assessment.

    PubMed

    Kurata, Masaaki; Horii, Ikuo

    2004-02-01

    In general toxicological studies, prothrombin time and activated partial thromboplastin time are routinely measured to assess blood coagulation. Special (problem-driven) tests for blood coagulation are of significance to detect abnormalities and investigate the mechanism of toxicity in detail. In this review, we compiled widely scattered information on blood coagulation testing from different fields in the biological area, and reviewed the methods available and their significance in toxicological studies. The relevant literature cited here reports large species differences in platelet aggregation, coagulation factors or fibrinolysis, and technical limitations. However, the following tests are basically applicable to laboratory animals; (1) assays for individual coagulation factors and protein induced by vitamin K absence or antagonists (PIVKA) to investigate coagulation factor abnormalities; (2) platelet aggregation-, platelet adhesion-, platelet release-tests and von Willebrand factor assay to screen and/or investigate platelet dysfunction; (3) fibrin/fibrinogen degradation products (FDP), D-dimer and thromboelastogram to detect fibrinolitic abnormalities, and assays for plasminogen, plasmin and their activator/inhibitor to investigate fibrinolysis in detail; and (4) bleeding-time to grossly evaluate blood coagulation capability in vivo. An appropriate battery of these tests provides significant information for risk assessment of drugs.

  7. A New Method for Assessing the Statistical Significance in the Differential Functioning of Items and Tests (DFIT) Framework

    ERIC Educational Resources Information Center

    Oshima, T. C.; Raju, Nambury S.; Nanda, Alice O.

    2006-01-01

    A new item parameter replication method is proposed for assessing the statistical significance of the noncompensatory differential item functioning (NCDIF) index associated with the differential functioning of items and tests framework. In this new method, a cutoff score for each item is determined by obtaining a (1-alpha ) percentile rank score…

  8. A New Method for Assessing the Statistical Significance in the Differential Functioning of Items and Tests (DFIT) Framework

    ERIC Educational Resources Information Center

    Oshima, T. C.; Raju, Nambury S.; Nanda, Alice O.

    2006-01-01

    A new item parameter replication method is proposed for assessing the statistical significance of the noncompensatory differential item functioning (NCDIF) index associated with the differential functioning of items and tests framework. In this new method, a cutoff score for each item is determined by obtaining a (1-alpha ) percentile rank score…

  9. Explanation of Significant Differences for the Record of Decision for the Test Area North Operable Unit 1-10

    SciTech Connect

    D. L. Eaton

    2007-01-18

    This Explanation of Significant Differences (ESD) applies to the remedial actions performed under the Final Record of Decision for Test Area North, Operable Unit 1-1 0, Idaho National Engineering and Environmental Laboratory (DOE-ID 1999) as amended by the Explanation of Significant Differences for the Record of Decision for the Test Area North Operable Unit 1-10 (DOE-ID 2003), the Record of Decision Amendment for the V-Tanks (TSF-09 and TSF-18) and Explanation of Significant Differences for the PM-2A Tanks (TSF-26) and TSF-06, Area IO, at Test Area North, Operable Unit 1-1 0 (DOE-ID 2004a), and the Explanation of Significant Differences for the Record of Decision for the Test Area North Operable Unit 1-10 (DOE-ID 2005). The U.S. Department of Energy (DOE) Idaho Operations Office; U.S. Environmental Protection Agency (EPA), Region 10; and the Idaho Department of Health and Welfare-now identified as the Idaho Department of Environmental Quality (DEQ)-signed the Record of Decision (ROD) in December 1999, the 2003 ESD in April 2003, the ROD Amendment/ESD in February 2004, and the 2005 ESD in January 2005. The EPA and DEQ support the need for this ESD.

  10. [Effects and significance of methacholine bronchial provocation tests and salbutamol bronchial dilation test on measurements of fractional exhaled nitric oxide in patients with asthma].

    PubMed

    Liu, Jielu; Yu, Huapeng; Tan, Xiaomei; Wu, Shuhan; Zhang, Pan; Fang, Zekui; Wang, Cuilan; He, Xi

    2016-03-01

    To study the effects and significance of methacholine (Mch) bronchial provocation tests and salbutamol bronchial dilation test on measurements of fractional exhaled nitric oxide (FeNO) in patients with asthma. This was a prospective study conducted between November 2014 and August 2015. A total of 135 patients with asthma visiting the respiratory clinic of Zhujiang Hospital were enrolled. The patients received either Mch bronchial provocation test or salbutamol bronchial dilation test based on their FEV1/FVC values and cooperative degree. Mch bronchial provocation test was performed by using Astograph Jupiter-21 (Astograh group) or APS-Pro airway reaction testing apparatus (APS group), and salbutamol bronchial dilation test was performed by using Jaeger spirometer (Dilation group). We compared the differences between FeNO values measured before examinations (Pre-FeNO) and 5 min after completion of these examinations (Post-FeNO). The geometric mean of Pre-FeNO and Post-FeNO was 28.07 ppb and 24.08 ppb respectively in the Astograh group, with a significant decrease of the FeNO value after the examination (Z=-3.093, P=0.002). A significant difference between Pre-FeNO and Post-FeNO was found in patients who had positive provocation results in the Astograh group (Z=-2.787, P=0.005), but not in the patients with negative results (Z=-1.355, P=0.176). The geometric mean of FeNO in the APS group decreased significantly from 27.95 ppb to 23.15 ppb after the examination was completed (Z=-5.170, P=0.000); both in patients with positive saline or Mch provocation results and in patients with negative provocation results, the differences between Pre-FeNO and Post-FeNO in the APS group being significant (Z=-2.705, -3.709, -2.371, P=0.002, 0.000, 0.018). No difference of FeNO change(ΔFeNO) was observed between the 2 Mch bronchial provocation test groups (U<918.000, P=0.117). The geometric mean of Pre-FeNO was 36.74 ppb and that of Post-FeNO was 34.79 ppb in the Dilation group; the

  11. Prognostic significance of cardiopulmonary exercise testing for 10-year survival in patients with mild to moderate heart failure.

    PubMed

    Koike, A; Koyama, Y; Itoh, H; Adachi, H; Marumo, F; Hiroe, M

    2000-12-01

    Although a number of studies have investigated the prognostic significance of exercise variables, they have focused only on short-term prognosis in relatively severe heart failure. This study was carried out to determine whether the indices obtained during cardiopulmonary exercise testing have prognostic significance during a 10-year follow-up in mild to moderate heart failure. Three hundred and sixty-four consecutive patients with cardiac disease performed 4 min of 20-W warm-up, followed by a symptom-limited incremental exercise test on a cycle ergometer. In addition to the measurements of peak oxygen uptake (VO2) and gas exchange (anaerobic) threshold, the time constant of VO2 kinetics during the onset of warm-up exercise was calculated using a single exponential equation. Data on mortality were available for follow-up in 260 patients. After 3,331+/-610 days of follow-up, 29 cardiovascular-related deaths occurred. The time constant of VO2 in the nonsurvivors was 76.7+/-43.3 s and was significantly prolonged compared with that of survivors (55.3+/-30.6 s, p=0.001). Peak VO2 and gas exchange threshold were both significantly lower in nonsurvivors than in survivors. Kaplan-Meier survival curves for 10 years of follow-up demonstrated a survival rate of 89.0% for patients with a normal VO2 time constant (< 80 s) and 71.7% for those with a longer time constant (> or = 80 s), showing a significant difference in survival (p=0.0028). Respiratory gas parameters obtained during exercise testing, particularly the time constant of VO2 kinetics, were found to be useful for predicting long-term prognosis in patients with chronic heart failure. These results suggest that cardiopulmonary exercise testing could be more applicable in ambulatory patients with minimal symptoms or minimal functional impairment.

  12. NAD+ administration significantly attenuates synchrotron radiation X-ray-induced DNA damage and structural alterations of rodent testes

    PubMed Central

    Sheng, Caibin; Chen, Heyu; Wang, Ban; Liu, Tengyuan; Hong, Yunyi; Shao, Jiaxiang; He, Xin; Ma, Yingxin; Nie, Hui; Liu, Na; Xia, Weiliang; Ying, Weihai

    2012-01-01

    Synchrotron radiation (SR) X-ray has great potential for its applications in medical imaging and cancer treatment. In order to apply SR X-ray in clinical settings, it is necessary to elucidate the mechanisms underlying the damaging effects of SR X-ray on normal tissues, and to search for the strategies to reduce the detrimental effects of SR X-ray on normal tissues. However, so far there has been little information on these topics. In this study we used the testes of rats as a model to characterize SR X-ray-induced tissue damage, and to test our hypothesis that NAD+ administration can prevent SR X-ray-induced injury of the testes. We first determined the effects of SR X-ray at the doses of 0, 0.5, 1.3, 4 and 40 Gy on the biochemical and structural properties of the testes one day after SR X-ray exposures. We found that 40 Gy of SR X-ray induced a massive increase in double-strand DNA damage, as assessed by both immunostaining and Western blot of phosphorylated H2AX levels, which was significantly decreased by intraperitoneally (i.p.) administered NAD+ at doses of 125 and 625 mg/kg. Forty Gy of SR X-ray can also induce marked increases in abnormal cell nuclei as well as significant decreases in the cell layers of the seminiferous tubules one day after SR X-ray exposures, which were also ameliorated by the NAD+ administration. In summary, our study has shown that SR X-ray can produce both molecular and structural alterations of the testes, which can be significantly attenuated by NAD+ administration. These results have provided not only the first evidence that SR X-ray-induced tissue damage can be ameliorated by certain approaches, but also a valuable basis for elucidating the mechanisms underlying SR X-ray-induced tissue injury. PMID:22518270

  13. Testing the significance of a correlation with nonnormal data: comparison of Pearson, Spearman, transformation, and resampling approaches.

    PubMed

    Bishara, Anthony J; Hittner, James B

    2012-09-01

    It is well known that when data are nonnormally distributed, a test of the significance of Pearson's r may inflate Type I error rates and reduce power. Statistics textbooks and the simulation literature provide several alternatives to Pearson's correlation. However, the relative performance of these alternatives has been unclear. Two simulation studies were conducted to compare 12 methods, including Pearson, Spearman's rank-order, transformation, and resampling approaches. With most sample sizes (n ≥ 20), Type I and Type II error rates were minimized by transforming the data to a normal shape prior to assessing the Pearson correlation. Among transformation approaches, a general purpose rank-based inverse normal transformation (i.e., transformation to rankit scores) was most beneficial. However, when samples were both small (n ≤ 10) and extremely nonnormal, the permutation test often outperformed other alternatives, including various bootstrap tests.

  14. The effects of radioisotopes used in nuclear medicine on diagnostic radioimmunoassay testing. Is there any significant interference?

    PubMed

    Riccio, J A; Maturani, D; Wright, J; Fleetwood, M K

    1990-11-01

    The administration of radioisotopes for diagnostic nuclear medicine scans and therapeutic procedures is quite prevalent today. A period of interference with the counting of a radioimmunoassay [RIA] test may occur with the serum of a patient receiving an in vivo radionuclide that decays by gamma emission. Because the logistics of precounting all specimens may be cumbersome and prohibitive, it is important to determine the degree of this interference. In this study, the authors evaluate the potential interference of the most commonly used radioisotopes with RIA studies. For two months (March and August 1988) 10,650 patient serum specimens were counted for significant background gamma radiation before RIA testing. Forty-three patients, on whom 105 RIA tests were performed, were identified as having preassay gamma radiation in their serum. With the use of selective energy windows for each different interfering radionuclide, proportional determinations were made as to the amount of interfering gamma radiation spilling into the iodine 125 test marker window. It was shown that initial whole serum pretest gamma counts as high as 111,000 counts/minute did not significantly affect the results of the RIA. Because of the meticulous washing and decanting procedures required in modern RIA and the monoclonal nature of most antibodies used currently, it appears the degree of nonspecific binding of this potentially interfering radiation is minuscule. The energy level of cobalt 57, however, and many of the other commonly used radioisotopes, overlaps so closely that it is difficult to window for this interference. It is possible, therefore, that this distinction cannot be made and folate and vitamin B12 test systems using cobalt 57 markers may have to be routinely prescreened. The authors conclude that the requirement for prescreening of all RIA test samples for interfering gamma radiation is unnecessary (1987 CAP Commission on Laboratory Accreditation Inspection Checklist, Section

  15. Functional testing strategy for coding genetic variants of unclear significance in MLH1 in Lynch syndrome diagnosis.

    PubMed

    Hinrichsen, Inga; Schäfer, Dieter; Langer, Deborah; Köger, Nicole; Wittmann, Margarethe; Aretz, Stefan; Steinke, Verena; Holzapfel, Stefanie; Trojan, Jörg; König, Rainer; Zeuzem, Stefan; Brieger, Angela; Plotz, Guido

    2015-02-01

    Lynch syndrome is caused by inactivating mutations in the MLH1 gene, but genetic variants of unclear significance frequently preclude diagnosis. Functional testing can reveal variant-conferred defects in gene or protein function. Based on functional defect frequencies and clinical applicability of test systems, we developed a functional testing strategy aimed at efficiently detecting pathogenic defects in coding MLH1 variants. In this strategy, tests of repair activity and expression are prioritized over analyses of subcellular protein localization and messenger RNA (mRNA) formation. This strategy was used for four unclear coding MLH1 variants (p.Asp41His, p.Leu507Phe, p.Gln689Arg, p.Glu605del + p.Val716Met). Expression was analyzed using a transfection system, mismatch repair (MMR) activity by complementation in vitro, mRNA formation by reverse transcriptase-PCR in carrier lymphocyte mRNA, and subcellular localization with dye-labeled fusion constructs. All tests included clinically meaningful controls. The strategy enabled efficient identification of defects in two unclear variants: the p.Asp41His variant showed loss of MMR activity, whereas the compound variant p.Glu605del + p.Val716Met had a defect of expression. This expression defect was significantly stronger than the pathogenic expression reference variant analyzed in parallel, therefore the defect of the compound variant is also pathogenic. Interestingly, the expression defect was caused additively by both of the compound variants, at least one of which is non-pathogenic when occurring by itself. Tests were neutral for p.Leu507Phe and p.Gln689Arg, and the results were consistent with available clinical data. We finally discuss the improved sensitivity and efficiency of the applied strategy and its limitations in analyzing unclear coding MLH1 variants.

  16. Significance of specificity of Tinetti B-POMA test and fall risk factor in third age of life.

    PubMed

    Avdić, Dijana; Pecar, Dzemal

    2006-02-01

    As for the third age, psychophysical abilities of humans gradually decrease, while the ability of adaptation to endogenous and exogenous burdens is going down. In 1987, "Harada" et al. (1) have found out that 9.5 million persons in USA have difficulties running daily activities, while 59% of them (which is 5.6 million) are older than 65 years in age. The study has encompassed 77 questioned persons of both sexes with their average age 71.73 +/- 5.63 (scope of 65-90 years in age), chosen by random sampling. Each patient has been questioned in his/her own home and familiar to great extent with the methodology and aims of the questionnaire. Percentage of questioned women was 64.94% (50 patients) while the percentage for men was 35.06% (27 patients). As for the value of risk factor score achieved conducting the questionnaire and B-POMA test, there are statistically significant differences between men and women, as well as between patients who fell and those who never did. As for the way of life (alone or in the community), there are no significant statistical differences. Average results gained through B-POMA test in this study are statistically significantly higher in men and patients who did not provide data about falling, while there was no statistically significant difference in the way of life. In relation to the percentage of maximum number of positive answers to particular questions, regarding gender, way of life and the data about falling, there were no statistically significant differences between the value of B-POMA test and the risk factor score (the questionnaire).

  17. [Physicians with access to point-of-care tests significantly reduce the antibiotic prescription for common cold].

    PubMed

    Llor, Carles; Hernández, Silvia; Cots, Josep María; Bjerrum, Lars; González, Beatriz; García, Guillermo; Alcántara, Juan de Dios; Guerra, Gloria; Cid, Marina; Gómez, Manuel; Ortega, Jesús; Pérez, Carolina; Arranz, Javier; Monedero, María José; Paredes, José; Pineda, Vicenta

    2013-03-01

    This study was aimed at evaluating the effect of two levels of intervention on the antibiotic prescribing in patients with common cold. Before and after audit-based study carried out in primary healthcare centres in Spain. General practitioners registered all the episodes of common cold during 15 working days in January and February in 2008 (preintervention). Two types of intervention were considered: full intervention, consisting in individual feedback based on results from the first registry, courses in rational antibiotic prescribing, guidelines, patient information leaflets, workshops on rapid tests -rapid antigen detection and C-reactive protein tests- and provision of these tests in the surgeries; and partial intervention, consisting of all the above intervention except for the workshop and they did not have access to rapid tests. The same registry was repeated in 2009 (postintervention). In addition, new physicians filled out only the registry in 2009 (control group). 210 physicians underwent the full intervention, 71 the partial intervention and 59 were assigned to the control group. The 340 doctors prescribed antibiotics in 274 episodes of a total of 12,373 cases registered (2.2%).The greatest percentage of antibiotic prescription was found in the control group (4.6%). The partial intervention increased the antibiotic prescription percentage from 1.1% to 2.7% while only doctors who underwent the complete intervention lead to a significant reduction of antibiotics prescribed, from 2.9% before to 0.7% after the intervention (p<0.001). Only physicians with access to rapid tests significantly reduced antibiotic prescription in patients with common cold.

  18. The effects of radioisotopes used in nuclear medicine on diagnostic radioimmunoassay testing. Is there any significant interference

    SciTech Connect

    Riccio, J.A.; Maturani, D.; Wright, J.; Fleetwood, M.K. )

    1990-11-01

    The administration of radioisotopes for diagnostic nuclear medicine scans and therapeutic procedures is quite prevalent today. A period of interference with the counting of a radioimmunoassay (RIA) test may occur with the serum of a patient receiving an in vivo radionuclide that decays by gamma emission. Because the logistics of precounting all specimens may be cumbersome and prohibitive, it is important to determine the degree of this interference. In this study, the authors evaluate the potential interference of the most commonly used radioisotopes with RIA studies. For two months (March and August 1988) 10,650 patient serum specimens were counted for significant background gamma radiation before RIA testing. Forty-three patients, on whom 105 RIA tests were performed, were identified as having preassay gamma radiation in their serum. With the use of selective energy windows for each different interfering radionuclide, proportional determinations were made as to the amount of interfering gamma radiation spilling into the iodine 125 test marker window. It was shown that initial whole serum pretest gamma counts as high as 111,000 counts/minute did not significantly affect the results of the RIA. Because of the meticulous washing and decanting procedures required in modern RIA and the monoclonal nature of most antibodies used currently, it appears the degree of nonspecific binding of this potentially interfering radiation is minuscule. The energy level of cobalt 57, however, and many of the other commonly used radioisotopes, overlaps so closely that it is difficult to window for this interference. It is possible, therefore, that this distinction cannot be made and folate and vitamin B12 test systems using cobalt 57 markers may have to be routinely prescreened.

  19. Dose-rate plays a significant role in synchrotron radiation X-ray-induced damage of rodent testes

    PubMed Central

    Chen, Heyu; Wang, Ban; Wang, Caixia; Cao, Wei; Zhang, Jie; Ma, Yingxin; Hong, Yunyi; Fu, Shen; Wu, Fan; Ying, Weihai

    2016-01-01

    Synchrotron radiation (SR) X-ray has significant potential for applications in medical imaging and cancer treatment. However, the mechanisms underlying SR X-ray-induced tissue damage remain unclear. Previous studies on regular X-ray-induced tissue damage have suggested that dose-rate could affect radiation damage. Because SR X-ray has exceedingly high dose-rate compared to regular X-ray, it remains to be determined if dose-rate may affect SR X-ray-induced tissue damage. We used rodent testes as a model to investigate the role of dose-rate in SR X-ray-induced tissue damage. One day after SR X-ray irradiation, we determined the effects of the irradiation of the same dosage at two different dose-rates, 0.11 Gy/s and 1.1 Gy/s, on TUNEL signals, caspase-3 activation and DNA double-strand breaks (DSBs) of the testes. Compared to those produced by the irradiation at 0.11 Gy/s, irradiation at 1.1 Gy/s produced higher levels of DSBs, TUNEL signals, and caspase-3 activation in the testes. Our study has provided the first evidence suggesting that dose-rate could be a significant factor in SR X-ray-induced tissue damage, which may establish a valuable base for utilizing this factor to manipulate the tissue damage in SR X-ray-based medical applications. PMID:28078052

  20. Dose-rate plays a significant role in synchrotron radiation X-ray-induced damage of rodent testes.

    PubMed

    Chen, Heyu; Wang, Ban; Wang, Caixia; Cao, Wei; Zhang, Jie; Ma, Yingxin; Hong, Yunyi; Fu, Shen; Wu, Fan; Ying, Weihai

    2016-01-01

    Synchrotron radiation (SR) X-ray has significant potential for applications in medical imaging and cancer treatment. However, the mechanisms underlying SR X-ray-induced tissue damage remain unclear. Previous studies on regular X-ray-induced tissue damage have suggested that dose-rate could affect radiation damage. Because SR X-ray has exceedingly high dose-rate compared to regular X-ray, it remains to be determined if dose-rate may affect SR X-ray-induced tissue damage. We used rodent testes as a model to investigate the role of dose-rate in SR X-ray-induced tissue damage. One day after SR X-ray irradiation, we determined the effects of the irradiation of the same dosage at two different dose-rates, 0.11 Gy/s and 1.1 Gy/s, on TUNEL signals, caspase-3 activation and DNA double-strand breaks (DSBs) of the testes. Compared to those produced by the irradiation at 0.11 Gy/s, irradiation at 1.1 Gy/s produced higher levels of DSBs, TUNEL signals, and caspase-3 activation in the testes. Our study has provided the first evidence suggesting that dose-rate could be a significant factor in SR X-ray-induced tissue damage, which may establish a valuable base for utilizing this factor to manipulate the tissue damage in SR X-ray-based medical applications.

  1. Performance of a New Rapid Immunoassay Test Kit for Point-of-Care Diagnosis of Significant Bacteriuria

    PubMed Central

    Cox, Marsha E.; DiNello, Robert K.; Geisberg, Mark; Abbott, April; Roberts, Pacita L.; Hooton, Thomas M.

    2015-01-01

    Urinary tract infections (UTIs) are frequently encountered in clinical practice and most commonly caused by Escherichia coli and other Gram-negative uropathogens. We tested RapidBac, a rapid immunoassay for bacteriuria developed by Silver Lake Research Corporation (SLRC), compared with standard bacterial culture using 966 clean-catch urine specimens submitted to a clinical microbiology laboratory in an urban academic medical center. RapidBac was performed in accordance with instructions, providing a positive or negative result in 20 min. RapidBac identified as positive 245/285 (sensitivity 86%) samples with significant bacteriuria, defined as the presence of a Gram-negative uropathogen or Staphylococcus saprophyticus at ≥103 CFU/ml. The sensitivities for Gram-negative bacteriuria at ≥104 CFU/ml and ≥105 CFU/ml were 96% and 99%, respectively. The specificity of the test, detecting the absence of significant bacteriuria, was 94%. The sensitivity and specificity of RapidBac were similar on samples from inpatient and outpatient settings, from male and female patients, and across age groups from 18 to 89 years old, although specificity was higher in men (100%) compared with that in women (92%). The RapidBac test for bacteriuria may be effective as an aid in the point-of-care diagnosis of UTIs especially in emergency and primary care settings. PMID:26063858

  2. Performance of a New Rapid Immunoassay Test Kit for Point-of-Care Diagnosis of Significant Bacteriuria.

    PubMed

    Stapleton, Ann E; Cox, Marsha E; DiNello, Robert K; Geisberg, Mark; Abbott, April; Roberts, Pacita L; Hooton, Thomas M

    2015-09-01

    Urinary tract infections (UTIs) are frequently encountered in clinical practice and most commonly caused by Escherichia coli and other Gram-negative uropathogens. We tested RapidBac, a rapid immunoassay for bacteriuria developed by Silver Lake Research Corporation (SLRC), compared with standard bacterial culture using 966 clean-catch urine specimens submitted to a clinical microbiology laboratory in an urban academic medical center. RapidBac was performed in accordance with instructions, providing a positive or negative result in 20 min. RapidBac identified as positive 245/285 (sensitivity 86%) samples with significant bacteriuria, defined as the presence of a Gram-negative uropathogen or Staphylococcus saprophyticus at ≥10(3) CFU/ml. The sensitivities for Gram-negative bacteriuria at ≥10(4) CFU/ml and ≥10(5) CFU/ml were 96% and 99%, respectively. The specificity of the test, detecting the absence of significant bacteriuria, was 94%. The sensitivity and specificity of RapidBac were similar on samples from inpatient and outpatient settings, from male and female patients, and across age groups from 18 to 89 years old, although specificity was higher in men (100%) compared with that in women (92%). The RapidBac test for bacteriuria may be effective as an aid in the point-of-care diagnosis of UTIs especially in emergency and primary care settings. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  3. Single-disk diffusion testing (Kirby-Bauer) of susceptibility of Proteus mirabilis to chloramphenicol: significance of the intermediate category.

    PubMed

    Furtado, G L; Medeiros, A A

    1980-10-01

    The significance of the intermediate category of the single-disk diffusion test (Kirby-Bauer) of antibiotic susceptibility has never been clearly defined. Thirty-two percent of 756 clinical isolates of Proteus mirabilis were of intermediate susceptibility to chloramphenicol, a higher percentage than for any other species. The breakpoint separating susceptible and intermediate isolates nearly bisected the frequency distribution of zone diameters of P. mirabilis but not that of the other species. The breakpoint separating susceptible and intermediate isolates nearly bisected the frequency distribution of zone diameters of P. mirabillis but not that of the other species tested. By serial broth dilution testing, the minimal inhibitory concentrations (MICs) of chloramphenicol of 50 individual isolates of P. mirabilis were 3.9 to 22.1 micrograms/ml (geometric mean, 8.0), whereas the MICs of susceptible Escherichia coli, Klebsiella, and Enterobacter strains were 2.0 to 3.9 micrograms/ml (geometric mean, 2.9). Seventy percent of isolates of P. mirabilis with MICs of 7.8 to 15.6 micrograms/ml were classified as susceptible by disk testing. We conclude that existing Kirby-Bauer breakpoints do not accurately discriminate P. mirabilis isolates that are marginally susceptible to chloramphenicol. These data underscore the difficulty of applying a single set of breakpoints to all species and suggest that species-specific breakpoints would more accurately predict the MIC equivalent of given zone diameters.

  4. Significance of serum antibody test for toxocariasis in healthy healthcare examinees with eosinophilia in Seoul and Gyeongsangnam-do, Korea.

    PubMed

    Kim, Hong Seok; Jin, Yan; Choi, Min-Ho; Kim, Jae-Hwan; Lee, Young Ha; Yoon, Cheong Ha; Hwang, Eui-Hyuk; Kang, Hun; Ahn, Sang-Yong; Kim, Gi Jin; Hong, Sung-Tae

    2014-12-01

    There have been numerous reports on the relationship between eosinophilia and toxocariasis. The present study investigated seropositive rates of toxocariasis among healthy people with or without eosinophilia in urban and rural areas, and assessed risk factors for positive antibody test. A total of 610 healthy people, who visited health check-up (Medicheck®, Korea Association of Health Promotion), 310 from Seoul and 300 from Gyeongsangnam-do, were subjected for this study. Their serum samples were tested by ELISA with the crude antigen of Toxocara canis larvae. Cross-reactions with other tissue invading helminth antigens were also investigated. Total antibody positive rate of toxocariasis was 8.7% of the 610 subjects. When the subjects were grouped into 3 by their eosinophil counts, the antibody positive rates significantly differed by the groups; 5.9% (18/306) in the group<350/µL, 10.0% (11/110) in the group 350-500/µL, and 12.4% (24/194) in the group>500/µL (P=0.028). A total of 22 serum samples cross-reacted with other tissue-invading helminth antigens. A questionnaire analysis recognized drinking alcohol and smoking as significant risk factors of toxocariasis. In conclusion, toxocariasis antibody positive rate is correlated with eosinophil counts. It is recommended that healthy subjects with eosinophilia by routine health examination and risk factors undergo Toxocara serology by multiantigen ELISA to investigate etiology.

  5. Clinical significance of a false positive glucose challenge test in patients with a high body mass index.

    PubMed

    Borja, Anne; Moretti, Michael; Lakhi, Nisha

    2017-04-01

    To determine if there is an increased maternal or neonatal morbidity in overweight and obese patients with a false positive glucose challenge test (GCT). Patients with a body mass index (BMI) ≥25.0 at registration were included in this prospective 36-month study. The study cohort consisted of patients with a false positive (FP) GCT, with two comparison cohorts: those with a (1) screen negative (SN) GCT result and (2) true positive (TP) GCT result. Risks were reported as odd ratios with 95% confidence intervals, with a P<0.05 considered as significant. There were 60 patients in the FP cohort, 106 in the SN cohort, and 64 in the TP cohort. When the BMI of the FP cohort was compared with either the SN cohort or TP cohort, differences were non-significant (SN 32.3 vs. FP 33.3 kg/m2, P=0.067) and (FP 33.3 vs. TP 34.4 kg/m2, P=0.303). When comparing the FP cohort to the SN cohort, patients in the FP group had significantly more gestational hypertension and pre-eclampsia. There was a trend towards delivering large for gestational weight infants and an infant ≥4000 g in the FP cohort, but this fell short of reaching statistical significance. When comparing the FP to TP cohorts, rates of gestational hypertension, pre-eclampsia, and infants ≥4000 g were similar; however, neonatal morbidity was increased in the TP group. Overweight and obese patients with a FP glucose challenge screen are more likely to have adverse maternal outcomes. Neonatal morbidity was not increased.

  6. Thymoquinone vapor significantly affects the results of Staphylococcus aureus sensitivity tests using the standard broth microdilution method.

    PubMed

    Novy, Pavel; Kloucek, Pavel; Rondevaldova, Johana; Havlik, Jaroslav; Kourimska, Lenka; Kokoska, Ladislav

    2014-04-01

    The broth microdilution (BMD) method is widely used for the determination of minimum inhibitory concentrations of antimicrobial agents, including volatile oils and their components. In this series of various experiments, we have demonstrated the influence of thymoquinone (TQ) vapor on the results of the BMD test performed with Staphylococcus aureus as a model organism. The spread of vapor from the TQ containing wells (32-512 μg/mL) caused the complete inhibition of staphylococcal growth in adjoining wells initially containing bacterium-inoculated pure Mueller-Hinton broth only and thus produced false positive results of the test. The ability of TQ to pass into the adjoined wells was subsequently confirmed by gas chromatography-mass spectrometry, whereas TQ at concentrations up to 84 μg/mL was detected in these wells after five hours. Based on these results, we suppose that vapors of TQ as well as of other naturally occurring volatile compounds and their mixtures (for example essential oils and plant extracts) can significantly influence results of the standard BMD assay. These observations, therefore, call for development of new appropriate BMD method suitable for assessment of antimicrobial activity of volatile substances. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Why do humans have chins? Testing the mechanical significance of modern human symphyseal morphology with finite element analysis.

    PubMed

    Gröning, Flora; Liu, Jia; Fagan, Michael J; O'Higgins, Paul

    2011-04-01

    The modern human mandibular symphysis differs from those of all other primates in being vertically orientated and possessing a chin, but the functional significance of this unique morphology is not well understood. Some hypotheses propose that it is an adaptation to specific loads occurring during masticatory function. This study uses finite element analysis to examine these symphyseal loads in a model of a modern human mandible. By modifying the symphyseal cross-sectional form, the mechanical significance of the presence of the chin and symphyseal orientation is tested, and modern human and Neanderthal symphyseal cross-sections are compared with regard to their ability to withstand different loads. The results show that changes in symphyseal form have profound effects on the strains. The presence of a chin leads to lower symphyseal strains overall, whereas a vertical orientation of the symphysis results in higher strains under wishboning, but not under vertical bending in the coronal plane and dorsoventral shear. Compared to Neanderthals, the modern human symphysis shows higher strains during dorsoventral shear and wishboning, but is as effective as the Neanderthal symphysis in resisting vertical bending in the coronal plane and the loads resulting from simulated incision and unilateral molar biting. In general, the results of this study corroborate prior hypotheses about the mechanical effects of the human chin and vertical symphyseal orientation and support the idea that the relative importance of wishboning and vertical bending in the coronal plane might have played a role in the evolution of modern human symphyseal morphology.

  8. Orientation feedback during simulated simple translation tests has little clinical significance on the magnitude and precision of glenohumeral joint translations.

    PubMed

    Musahl, Volker; Moore, Susan M; McMahon, Patrick J; Debski, Richard E

    2006-11-01

    The repeatability of shoulder instability clinical examinations has been reported to be poor, producing a large range of translations. The objective of this study was to determine the effect of providing the clinician with joint orientation feedback on the magnitude and precision of glenohumeral joint kinematics. A 6-degree of freedom magnetic tracking system was used to determine the kinematics of the humerus with respect to the scapula (n=8 cadaveric shoulders). The joints were preconditioned with simple loading tests five times. At 60 degrees of glenohumeral abduction and 0 degrees of flexion/extension, a clinician then applied an anterior and posterior load to the humerus until a manual maximum simulating a simple translation test (STT) was achieved at 0, 30, and 60 degrees of external rotation with and without angular orientation feedback of the humerus with respect to the scapula. The precision for the external rotation was within 4.3 degrees for the feedback group and 17.5 degrees for the no feedback group over all external rotations. For achieving the target external rotation of 30 degrees , there was a significant difference in precision between the feedback and no feedback groups (p<0.05). The magnitudes of the anterior translations were 18.2+/-5.3, 15.5+/-5.1, and 9.9+/-5.5 mm for the feedback group and 19.3+/-6.6, 17.5+/-4.9, and 11.5+/-5.3 mm for the no feedback group, at 0, 30, and 60 degrees of external rotation, respectively. There was a significant difference in the precision of anterior translation at 30 and 60 degrees of external rotation for 4 of 8 specimens (p<0.05). Significant differences in the precision of the posterior translation was only detected at 0 degrees of external rotation for 3 of 8 specimens (p<0.05). Based on the data obtained, providing orientation feedback to a clinician performing a simulated STT results in increased precision for not only the target external rotations but also the resulting glenohumeral translations. While

  9. Testing earthquake prediction algorithms: Statistically significant advance prediction of the largest earthquakes in the Circum-Pacific, 1992-1997

    USGS Publications Warehouse

    Kossobokov, V.G.; Romashkova, L.L.; Keilis-Borok, V. I.; Healy, J.H.

    1999-01-01

    Algorithms M8 and MSc (i.e., the Mendocino Scenario) were used in a real-time intermediate-term research prediction of the strongest earthquakes in the Circum-Pacific seismic belt. Predictions are made by M8 first. Then, the areas of alarm are reduced by MSc at the cost that some earthquakes are missed in the second approximation of prediction. In 1992-1997, five earthquakes of magnitude 8 and above occurred in the test area: all of them were predicted by M8 and MSc identified correctly the locations of four of them. The space-time volume of the alarms is 36% and 18%, correspondingly, when estimated with a normalized product measure of empirical distribution of epicenters and uniform time. The statistical significance of the achieved results is beyond 99% both for M8 and MSc. For magnitude 7.5 + , 10 out of 19 earthquakes were predicted by M8 in 40% and five were predicted by M8-MSc in 13% of the total volume considered. This implies a significance level of 81% for M8 and 92% for M8-MSc. The lower significance levels might result from a global change in seismic regime in 1993-1996, when the rate of the largest events has doubled and all of them become exclusively normal or reversed faults. The predictions are fully reproducible; the algorithms M8 and MSc in complete formal definitions were published before we started our experiment [Keilis-Borok, V.I., Kossobokov, V.G., 1990. Premonitory activation of seismic flow: Algorithm M8, Phys. Earth and Planet. Inter. 61, 73-83; Kossobokov, V.G., Keilis-Borok, V.I., Smith, S.W., 1990. Localization of intermediate-term earthquake prediction, J. Geophys. Res., 95, 19763-19772; Healy, J.H., Kossobokov, V.G., Dewey, J.W., 1992. A test to evaluate the earthquake prediction algorithm, M8. U.S. Geol. Surv. OFR 92-401]. M8 is available from the IASPEI Software Library [Healy, J.H., Keilis-Borok, V.I., Lee, W.H.K. (Eds.), 1997. Algorithms for Earthquake Statistics and Prediction, Vol. 6. IASPEI Software Library]. ?? 1999 Elsevier

  10. Identifying significant gene‐environment interactions using a combination of screening testing and hierarchical false discovery rate control

    PubMed Central

    Shen, Li; Saykin, Andrew J.; Williams, Scott M.; Moore, Jason H.

    2016-01-01

    ABSTRACT Although gene‐environment (G× E) interactions play an important role in many biological systems, detecting these interactions within genome‐wide data can be challenging due to the loss in statistical power incurred by multiple hypothesis correction. To address the challenge of poor power and the limitations of existing multistage methods, we recently developed a screening‐testing approach for G× E interaction detection that combines elastic net penalized regression with joint estimation to support a single omnibus test for the presence of G× E interactions. In our original work on this technique, however, we did not assess type I error control or power and evaluated the method using just a single, small bladder cancer data set. In this paper, we extend the original method in two important directions and provide a more rigorous performance evaluation. First, we introduce a hierarchical false discovery rate approach to formally assess the significance of individual G× E interactions. Second, to support the analysis of truly genome‐wide data sets, we incorporate a score statistic‐based prescreening step to reduce the number of single nucleotide polymorphisms prior to fitting the first stage penalized regression model. To assess the statistical properties of our method, we compare the type I error rate and statistical power of our approach with competing techniques using both simple simulation designs as well as designs based on real disease architectures. Finally, we demonstrate the ability of our approach to identify biologically plausible SNP‐education interactions relative to Alzheimer's disease status using genome‐wide association study data from the Alzheimer's Disease Neuroimaging Initiative (ADNI). PMID:27578615

  11. Evidence for the different physiological significance of the 6- and 2-minute walk tests in multiple sclerosis

    PubMed Central

    2012-01-01

    Background Researchers have recently advocated for the 2-minute walk (2MW) as an alternative for the 6-minute walk (6MW) to assess long distance ambulation in persons with multiple sclerosis (MS). This recommendation has not been based on physiological considerations such as the rate of oxygen consumption (V·O2) over the 6MW range. Objective This study examined the pattern of change in V·O2 over the range of the 6MW in a large sample of persons with MS who varied as a function of disability status. Method Ninety-five persons with clinically-definite MS underwent a neurological examination for generating an Expanded Disability Status Scale (EDSS) score, and then completion of the 6MW protocol while wearing a portable metabolic unit and an accelerometer. Results There was a time main effect on V·O2 during the 6MW (p = .0001) such that V·O2 increased significantly every 30 seconds over the first 3 minutes of the 6MW, and then remained stable over the second 3 minutes of the 6MW. This occurred despite no change in cadence across the 6MW (p = .84). Conclusions The pattern of change in V·O2 indicates that there are different metabolic systems providing energy for ambulation during the 6MW in MS subjects and steady state aerobic metabolism is reached during the last 3 minutes of the 6MW. By extension, the first 3 minutes would represent a test of mixed aerobic and anaerobic work, whereas the second 3 minutes would represent a test of aerobic work during walking. PMID:22380843

  12. [Clinical studies in working populations: value and significance of anamnestic findings, clinical tests and instrumental tests for the diagnosis of musculoskeletal disorders of the upper extremities].

    PubMed

    De Marco, F; Menoni, O; Ricci, M G; Bonaiuti, D; Colombini, D; Occhipinti, E

    1996-01-01

    The authors discuss the value and significance of symptoms in WMSDs, considering that the anamnestic threshold proposed in epidemiological investigations cannot be used as clinical and diagnosing criteria. Some useful clinical procedures are suggested for cases where there is a suspicion of musculo-skeletal disorders of the cervical spine and upper limbs, bearing in mind that they are to be applied within the framework of health surveillance programmes undertaken by health care practitioners who are not specialists in orthopaedics, physiatrics or neurology. The recommendations for instrumental tests and specialist referrals are also discussed for the various disorders. The authors also provide flow charts for the diagnostic procedures pertaining to WMSDs. The Appendix shows a sample patient chart illustrating the proposed procedures; it also permits the findings to be encoded so that they can be stored in a dedicated database. The codes for diagnosing WMSDs are also reported for the same epidemiological purposes.

  13. Spore test parameters matter: Mesophilic and thermophilic spore counts detected in raw milk and dairy powders differ significantly by test method.

    PubMed

    Kent, D J; Chauhan, K; Boor, K J; Wiedmann, M; Martin, N H

    2016-07-01

    United States dairy industry exports have steadily risen in importance over the last 10yr, with dairy powders playing a particularly critical role. Currently, approximately half of US-produced nonfat dry milk and skim milk powder is exported. Reaching new and expanding existing export markets relies in part on the control of endospore-forming bacteria in dairy powders. This study reports baseline mesophilic and thermophilic spore counts and spore populations from 55 raw material samples (primarily raw milk) and 33 dairy powder samples from dairy powder processors across the United States. Samples were evaluated using various spore testing methodologies and included initial heat treatments of (1) 80°C for 12 min; (2) 100°C for 30 min; and (3) 106°C for 30 min. Results indicate that significant differences in both the level and population of spores were found for both raw milk and dairy powders with the various testing methods. Additionally, on average, spore counts were not found to increase significantly from the beginning to the end of dairy powder processing, most likely related to the absence of biofilm formation by processing plant-associated sporeformers (e.g., Anoxybacillus sp.) in the facilities sampled. Finally, in agreement with other studies, Bacillus licheniformis was found to be the most prevalent sporeformer in both raw materials and dairy powders, highlighting the importance of this organism in developing strategies for control and reduction of spore counts in dairy powders. Overall, this study emphasizes the need for standardization of spore enumeration methodologies in the dairy powder industry.

  14. A Rickettsiella Bacterium from the Hard Tick, Ixodes woodi: Molecular Taxonomy Combining Multilocus Sequence Typing (MLST) with Significance Testing

    PubMed Central

    Leclerque, Andreas; Kleespies, Regina G.

    2012-01-01

    Hard ticks (Acari: Ixodidae) are known to harbour intracellular bacteria from several phylogenetic groups that can develop both mutualistic and pathogenic relationships to the host. This is of particular importance for public health as tick derived bacteria can potentially be transmitted to mammals, including humans, where e.g. Rickettsia or Coxiella act as severe pathogens. Exact molecular taxonomic identification of tick associated prokaryotes is a necessary prerequisite of the investigation of their relationship to both the tick and possible vertebrate hosts. Previously, an intracellular bacterium had been isolated from a monosexual, parthenogenetically reproducing laboratory colony of females of the hard tick, Ixodes woodi Bishopp, and had preliminarily been characterized as a “Rickettsiella-related bacterium”. In the present molecular taxonomic study that is based on phylogenetic reconstruction from both 16 S ribosomal RNA and protein-encoding marker sequences complemented with likelihood-based significance testing, the bacterium from I. woodi has been identified as a strain of the taxonomic species Rickettsiella grylli. It is the first time that a multilocus sequence typing (MLST) approach based on a four genes comprising MLST scheme has been implemented in order to classify a Rickettsiella-like bacterium to this species. The study demonstrated that MLST holds potential for a better resolution of phylogenetic relationships within the genus Rickettsiella, but requires sequence determination from further Rickettsiella-like bacteria in order to complete the current still fragmentary picture of Rickettsiella systematics. PMID:22675436

  15. A Rickettsiella bacterium from the hard tick, Ixodes woodi: molecular taxonomy combining multilocus sequence typing (MLST) with significance testing.

    PubMed

    Leclerque, Andreas; Kleespies, Regina G

    2012-01-01

    Hard ticks (Acari: Ixodidae) are known to harbour intracellular bacteria from several phylogenetic groups that can develop both mutualistic and pathogenic relationships to the host. This is of particular importance for public health as tick derived bacteria can potentially be transmitted to mammals, including humans, where e.g. Rickettsia or Coxiella act as severe pathogens. Exact molecular taxonomic identification of tick associated prokaryotes is a necessary prerequisite of the investigation of their relationship to both the tick and possible vertebrate hosts. Previously, an intracellular bacterium had been isolated from a monosexual, parthenogenetically reproducing laboratory colony of females of the hard tick, Ixodes woodi Bishopp, and had preliminarily been characterized as a "Rickettsiella-related bacterium". In the present molecular taxonomic study that is based on phylogenetic reconstruction from both 16 S ribosomal RNA and protein-encoding marker sequences complemented with likelihood-based significance testing, the bacterium from I. woodi has been identified as a strain of the taxonomic species Rickettsiella grylli. It is the first time that a multilocus sequence typing (MLST) approach based on a four genes comprising MLST scheme has been implemented in order to classify a Rickettsiella-like bacterium to this species. The study demonstrated that MLST holds potential for a better resolution of phylogenetic relationships within the genus Rickettsiella, but requires sequence determination from further Rickettsiella-like bacteria in order to complete the current still fragmentary picture of Rickettsiella systematics.

  16. Chinese Students' Perceptions of the Value of Test Preparation Courses for the TOEFL iBT: Merit, Worth, and Significance

    ERIC Educational Resources Information Center

    Ma, Jia; Cheng, Liying

    2015-01-01

    Test preparation for high-stakes English language tests has received increasing research attention in the language assessment field; however, little is known about what aspects of test preparation students attend to and value. In this study, we considered the perspectives of 12 Chinese students who were enrolled in various academic programs in a…

  17. Quantification and physiological significance of the rightward shift of the V-slope during incremental cardiopulmonary exercise testing.

    PubMed

    Nishijima, Hirotaka; Kondo, Kazuo; Yonezawa, Kazuya; Hashimoto, Hiroki; Sakurai, Masayuki

    2017-01-01

    Ventilatory anaerobic threshold (VAT) is frequently used as a measure of exercise tolerance, with the V-slope method being the standard; however, this needs to be visually determined. Over the years, we have observed that the V-slope itself often appears to shift rightward before the appearance of the VAT (RtShift: rightward shift of V-slope). This phenomenon has long been known to occur during the first 1-2 min of steady-state exercise and disappears thereafter; it is attributed to CO2 storage, presumably in active muscle. However, during incremental exercise, we have observed that the RtShift persists; furthermore, it seems to be related to the level of VAT. Therefore, we attempted to objectively quantify the RtShift, and to confirm its relationship to an index of exercise tolerance (VAT). This study was based on a retrospective analysis of data from 100 cardiopulmonary ramp exercise tests (submaximal) performed by patients with cardiac disease. VAT was determined with the visual V-slope method. The horizontal distances between the diagonal R = 1 line and each data point on the V-slope plot to the right of R = 1 were measured; the average of these measurements was used as an objectively determined estimate of RtShift. The predominant portion of RtShift occurred earlier than VAT. The mean RtShift was 33.9 ± 25.0 mL⋅min(-1) VO2, whereas the mean VAT was 635 ± 220 mL⋅min(-1). RtShift positively correlated with VAT (r = 718, p < 0.001), confirming previous visual observations. It also significantly correlated with ΔVO2/Δwork rate, a marker of oxygen uptake efficiency (r = 0.531, p < 0.001). We identified that among patients with cardiac disease, V-slope is shifted rightward to varying degrees. The objectively quantified rightward shift of V-slope is significantly correlated with an index of exercise tolerance (VAT). Furthermore, it appears to occur at even lower work rates. This may offer a new objective means of estimating

  18. Routine Laboratory Blood Tests May Diagnose Significant Fibrosis in Liver Transplant Recipients with Chronic Hepatitis C: A 10 Year Experience.

    PubMed

    Sheen, Victoria; Nguyen, Heajung; Jimenez, Melissa; Agopian, Vatche; Vangala, Sitaram; Elashoff, David; Saab, Sammy

    2016-03-28

    The aims of our study were to determine whether routine blood tests, the aspartate aminotransferase (AST) to Platelet Ratio Index (APRI) and Fibrosis 4 (Fib-4) scores, were associated with advanced fibrosis and to create a novel model in liver transplant recipients with chronic hepatitis C virus (HCV). We performed a cross sectional study of patients at The University of California at Los Angeles (UCLA) Medical Center who underwent liver transplantation for HCV. We used linear mixed effects models to analyze association between fibrosis severity and individual biochemical markers and mixed effects logistic regression to construct diagnostic models for advanced fibrosis (METAVIR F3-4). Cross-validation was used to estimate a receiving operator characteristic (ROC) curve for the prediction models and to estimate the area under the curve (AUC). The mean (± standard deviation [SD]) age of our cohort was 55 (±7.7) years, and almost three quarter were male. The mean (±SD) time from transplant to liver biopsy was 19.9 (±17.1) months. The mean (±SD) APRI and Fib-4 scores were 3 (±12) and 7 (±14), respectively. Increased fibrosis was associated with lower platelet count and alanine aminotransferase (ALT) values and higher total bilirubin and Fib-4 scores. We developed a model that takes into account age, gender, platelet count, ALT, and total bilirubin, and this model outperformed APRI and Fib-4 with an AUC of 0.68 (p < 0.001). Our novel prediction model diagnosed the presence of advanced fibrosis more reliably than APRI and Fib-4 scores. This noninvasive calculation may be used clinically to identify liver transplant recipients with HCV with significant liver damage.

  19. Routine Laboratory Blood Tests May Diagnose Significant Fibrosis in Liver Transplant Recipients with Chronic Hepatitis C: A 10 Year Experience

    PubMed Central

    Sheen, Victoria; Nguyen, Heajung; Jimenez, Melissa; Agopian, Vatche; Vangala, Sitaram; Elashoff, David; Saab, Sammy

    2016-01-01

    Background and Aims: The aims of our study were to determine whether routine blood tests, the aspartate aminotransferase (AST) to Platelet Ratio Index (APRI) and Fibrosis 4 (Fib-4) scores, were associated with advanced fibrosis and to create a novel model in liver transplant recipients with chronic hepatitis C virus (HCV). Methods: We performed a cross sectional study of patients at The University of California at Los Angeles (UCLA) Medical Center who underwent liver transplantation for HCV. We used linear mixed effects models to analyze association between fibrosis severity and individual biochemical markers and mixed effects logistic regression to construct diagnostic models for advanced fibrosis (METAVIR F3-4). Cross-validation was used to estimate a receiving operator characteristic (ROC) curve for the prediction models and to estimate the area under the curve (AUC). Results: The mean (± standard deviation [SD]) age of our cohort was 55 (±7.7) years, and almost three quarter were male. The mean (±SD) time from transplant to liver biopsy was 19.9 (±17.1) months. The mean (±SD) APRI and Fib-4 scores were 3 (±12) and 7 (±14), respectively. Increased fibrosis was associated with lower platelet count and alanine aminotransferase (ALT) values and higher total bilirubin and Fib-4 scores. We developed a model that takes into account age, gender, platelet count, ALT, and total bilirubin, and this model outperformed APRI and Fib-4 with an AUC of 0.68 (p < 0.001). Conclusions: Our novel prediction model diagnosed the presence of advanced fibrosis more reliably than APRI and Fib-4 scores. This noninvasive calculation may be used clinically to identify liver transplant recipients with HCV with significant liver damage. PMID:27047768

  20. Significance of Iron(II,III) Hydroxycarbonate Green Rust in Arsenic Remediation Using Zerovalent Iron in Laboratory Column Tests

    EPA Science Inventory

    We examined the corrosion products of zerovalent iron used in three column tests for removing arsenic from water under dynamic flow conditions. Each column test lasted three- to four-months using columns consisting of a 10.3-cm depth of 50 : 50 (w : w, Peerless iron : sand) in t...

  1. Significance of Iron(II,III) Hydroxycarbonate Green Rust in Arsenic Remediation Using Zerovalent Iron in Laboratory Column Tests

    EPA Science Inventory

    We examined the corrosion products of zerovalent iron used in three column tests for removing arsenic from water under dynamic flow conditions. Each column test lasted three- to four-months using columns consisting of a 10.3-cm depth of 50 : 50 (w : w, Peerless iron : sand) in t...

  2. Of Minima and Maxima: The Social Significance of Minimal Competency Testing and the Search for Educational Excellence.

    ERIC Educational Resources Information Center

    Ericson, David P.

    1984-01-01

    Explores the many meanings of the minimal competency testing movement and the more recent mobilization for educational excellence in the schools. Argues that increasing the value of the diploma by setting performance standards on minimal competency tests and by elevating academic graduation standards may strongly conflict with policies encouraging…

  3. Significance of pregnancy test false negative results due to elevated levels of β-core fragment hCG.

    PubMed

    Johnson, Sarah; Eapen, Saji; Smith, Peter; Warren, Graham; Zinaman, Michael

    2017-01-01

    Very high levels of β-core fragment human chorionic gonadotrophin (βcf-hCG) are reported to potentially cause false negative results in point-of-care (POC)/over-the-counter (OTC) pregnancy tests. To investigate this further, women's daily early morning urine samples, collected prior to conception and during pregnancy, were analysed for intact, free β-, and βcf-hCG. The proportion of βcf-hCG was found to be related to that of hCG produced and in circulation. Therefore, best practice for accuracy testing of POC/OTC pregnancy tests would be to test devices against clinical samples containing high levels of βcf-hCG as well as standards spiked with biologically relevant ratios.

  4. Using the Coefficient of Determination "R"[superscript 2] to Test the Significance of Multiple Linear Regression

    ERIC Educational Resources Information Center

    Quinino, Roberto C.; Reis, Edna A.; Bessegato, Lupercio F.

    2013-01-01

    This article proposes the use of the coefficient of determination as a statistic for hypothesis testing in multiple linear regression based on distributions acquired by beta sampling. (Contains 3 figures.)

  5. Using the Coefficient of Determination "R"[superscript 2] to Test the Significance of Multiple Linear Regression

    ERIC Educational Resources Information Center

    Quinino, Roberto C.; Reis, Edna A.; Bessegato, Lupercio F.

    2013-01-01

    This article proposes the use of the coefficient of determination as a statistic for hypothesis testing in multiple linear regression based on distributions acquired by beta sampling. (Contains 3 figures.)

  6. State of the Art in Statistical Significance Testing: A Review of the APA Task Force on Statistical Inference's Report and Current Trends.

    ERIC Educational Resources Information Center

    Smith, A. Delany; Henson, Robin K.

    This paper addresses the state of the art regarding the use of statistical significance tests (SSTs). How social science research will be conducted in the future is impacted directly by current debates regarding hypothesis testing. This paper: (1) briefly explicates the current debate on hypothesis testing; (2) reviews the newly published report…

  7. [Different significance in normal subjects and in glaucoma patients tested with Optopol PTS-910, in the galucoma program].

    PubMed

    Dascalu, Ana Maria; Cherecheanu, Alina Popa; Stana, Daniela; Serban, Dragoş

    2013-01-01

    to quantify the inter-test variability (dB) for the Optopol PTS automated perimeter, Glaucoma Fast threshold program. A prospective study was performed on 166 glaucomatous patients and a control group of 30 normal subjects, tested by complete ophthalmological exam and automated perimetry (Optopol PTS-910). The visual field was tested weekly for 4 consecutive weeks. The visual field defects were classified according to the Aulhorn-Karmeyer descriptive scale. For the control group, the medium inter-test variability was of 1.57 +/- 0.24 dB, lower next to fixation and increasing towards the 50 degree isopter. The medium inter-test variability increases along with the perimetric stage :1.57 +/- 0.66 dB for pre-perimetric glaucoma, 2.13 + 1.04 dB for non-specific defects group, 3.23 + 1.01 dB for the stage 1, 3.52 + 2.61 dB, for the stage 2, 3.65 + 1.19dB for the stage 3 and 5.82 +/- 1.67dB for the stage 4. For the cases of preperimetric glaucoma and non-specific defects, a similar profile of variability to the normal subjects can be observed. For the stages 2-4, the profile of the areas with maxim inter-test variability moves towards the relative scotoma and the surrounding area. A better description of the inter-test variability and the evolution of this intricate parameter of the retinal light sensitivity is useful for the differential diagnostic between the real change and the "background noise" in early detection of the functional progression in glaucoma.

  8. Clinical Significance of Low Result of 1-hour 50-g Glucose-Challenge Test in Pregnant Women.

    PubMed

    Oawada, Nozomi; Aoki, Shigeru; Sakamaki, Kentaro; Obata, Soichiro; Seki, Kazuo; Hirahara, Fumiki

    2017-08-22

    To examine the effect of low glucose value on the 1-hour 50-g Glucose Challenge Test (GCT) on neonatal body weight in low-risk Asian singleton pregnant women. We retrospectively analyzed women who delivered a singleton neonate at term at a tertiary center and underwent GCT at 24-28 weeks of gestation between June 2001 and June 2015. Low GCT group was defined as < 75 mg/dL, and 75-139 mg/dL were control. We compared these two groups of maternal characteristics, small for gestational age neonate (SGA), large for gestational age neonate (LGA), low-birth weight, and macrosomia. The Χ2 test, Fisher's exact test, and Student's t test were used. There were 313 low GCT group, and 4611 control. Low GCT group were younger, had lower prepregnancy body weight, higher stature, and lower prepregnancy body mass index (BMI). After adjusting these variables, the low GCT group had a lower rate of LGA and a higher rate of SGA. Neonatal body weight is more influenced by maternal physique than by low GCT result (Standardized coefficient (β)(β); GCT 0.071, height 0.188, prepregnancy BMI 0.143). Neonatal body weight was only slightly influenced by low GCT result, but markedly influenced by maternal physique, such as height and prepregnancy BMI.

  9. 77 FR 21065 - Certain High Production Volume Chemicals; Test Rule and Significant New Use Rule; Fourth Group of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-09

    ... substances under the Toxic Substances Control Act (TSCA). The test rule would require manufacturers and... of uses, that would be reasonably likely to expose 1,000 or more workers at a single-corporate entity... CONTACT: For technical information contact: Robert Jones or Paul Campanella, Chemical Control Division...

  10. Exercise testing in patients with variant angina: results, correlation with clinical and angiographic features and prognostic significance

    SciTech Connect

    Waters, D.D.; Szlachcic, J.; Bourassa, M.G.; Scholl, J.-M.; Theroux, P.

    1982-02-01

    Eighty-two patients with variant angina underwent a treadmill exercise test using 14 ECG leads, and 67 also underwent exercise thallium-201 scans. The test induced ST elevation in 25 patients (30%), ST depression in 21 (26%) and no ST-segment abnormality in 36 (44%). ST elevation during exercise occurred in the same ECG leads as during spontaneous attacks at rest, and was always associated with a large perfusion defect on the exercise thallium scan. In contrast, exercise-induced ST depression often did not occur in the leads that exhibited ST elevation during episodes at rest. The ST-segment response to exercise did not accurately predict coronary anatomy: Coronary stenoses greater than or equal to 70% were present in 14 of 25 patients (56%) with ST elevation, in 13 of 21 (62%) with ST depression and in 14 of 36 (39%) with no ST-segment abnormality (NS). However, the degree of disease activity did correlate with the result of the exercise test: ST elevation occurred during exercise in 11 of 14 patients who had an average of more than two spontaneous attacks per day, in 12 of 24 who had between two attacks per day and two per week, and in only two of 31 who had fewer than two attacks per week (p<0.005). ST elevation during exercise was reproducible in five of five patients retested during an active phase of their disease, but not in three of three patients who had been angina-free for a least 1 month before the repeat test. We conclude that in variant angina patients, the results of an exercise test correlate well with the degree of disease activity but not with coronary anatomy, and do not define a high-risk subgroup.

  11. Implementation and Operational Research: Expedited Results Delivery Systems Using GPRS Technology Significantly Reduce Early Infant Diagnosis Test Turnaround Times.

    PubMed

    Deo, Sarang; Crea, Lindy; Quevedo, Jorge; Lehe, Jonathan; Vojnov, Lara; Peter, Trevor; Jani, Ilesh

    2015-09-01

    The objective of this study was to quantify the impact of a new technology to communicate the results of an infant HIV diagnostic test on test turnaround time and to quantify the association between late delivery of test results and patient loss to follow-up. We used data collected during a pilot implementation of Global Package Radio Service (GPRS) printers for communicating results in the early infant diagnosis program in Mozambique from 2008 through 2010. Our dataset comprised 1757 patient records, of which 767 were from before implementation and 990 from after implementation of expedited results delivery system. We used multivariate logistic regression model to determine the association between late result delivery (more than 30 days between sample collection and result delivery to the health facility) and the probability of result collection by the infant's caregiver. We used a sample selection model to determine the association between late result delivery to the facility and further delay in collection of results by the caregiver. The mean test turnaround time reduced from 68.13 to 41.05 days post-expedited results delivery system. Caregivers collected only 665 (37.8%) of the 1757 results. After controlling for confounders, the late delivery of results was associated with a reduction of approximately 18% (0.44 vs. 0.36; P < 0.01) in the probability of results collected by the caregivers (odds ratio = 0.67, P < 0.05). Late delivery of results was also associated with a further average increase in 20.91 days of delay in collection of results (P < 0.01). Early infant diagnosis program managers should further evaluate the cost-effectiveness of operational interventions (eg, GPRS printers) that reduce delays.

  12. DOD Operational Testing: Oversight Has Resulted in Few Significant Disputes and Limited Program Cost and Schedule Increases

    DTIC Science & Technology

    2015-06-01

    the scope of operational testing and better understanding of system requirements. Resolution of disputes for three programs—DDG-51 Flight III ...for three programs—DDG-51 Flight III Destroyer, F-35 Joint A Variety of Factors Contributed to Disputes We Reviewed, but Only a Few Cases Had...Ford Class Aircraft Carrier X DDG-51 Flight III Destroyer / AN/SPY-6 Radar / Aegis Modernization X DOD Automated Biometrics Identification

  13. The prevalence and significance of high-risk human papillomavirus DNA test in southern Malaysia and Singapore.

    PubMed

    Tay, Sun-Kuie; Tay, Yeng-Kwang

    2009-06-01

    To investigate the prevalence of high-risk human papillomavirus (HPV) and its associated cytological abnormalities among women attending cervical screening clinics in southern Malaysia and Singapore. Laboratory results of Hybrid Capture-II (Digene) HPV DNA and liquid-based cytology tests of consecutive women who had screening performed between January 2004 and December 2006 were studied retrospectively. Of 2364 women studied, the overall prevalence of high-risk HPV DNA detection rate was 25.6%. The prevalence peaked at 49.1% for women between 20 and 24 years old and declined to 23% among women between the age of 30 and 49 years. A small second peak of prevalence rate of 30% was observed among women above the age of 50 years old. 76.1% of the high-risk HPV infection regressed within the study period. An incidence infection rate of 16% was noted among a small group of women who had a second HPV DNA test. A total of 1153 women had both the HPV DNA and the cytology tests. Cytological abnormality (ASCUS or more) was detected in 8.9% in HPV DNA-positive group and in 3.1% in HPV DNA-negative group (P < 0.001). The risk ratio for HSIL was 9.8 for HPV-positive women compared to HPV-negative women. The prevalence of cytological abnormalities increased with increasing age of the women. The epidemiology and clinical impact of high-risk HPV infection for women in Southern Malaysia and Singapore were indistinguishable from experience elsewhere. The apparent moderately high incidence of cervical cancer was explainable by suboptimal screening program.

  14. Limitations of Significance Testing in Clinical Research: A Review of Multiple Comparison Corrections and Effect Size Calculations with Correlated Measures.

    PubMed

    Vasilopoulos, Terrie; Morey, Timothy E; Dhatariya, Ketan; Rice, Mark J

    2016-03-01

    Modern clinical research commonly uses complex designs with multiple related outcomes, including repeated-measures designs. While multiple comparison corrections and effect size calculations are needed to more accurately assess an intervention's significance and impact, understanding the limitations of these methods in the case of dependency and correlation is important. In this review, we outline methods for multiple comparison corrections and effect size calculations and considerations in cases of correlation and summarize relevant simulation studies to illustrate these concepts.

  15. Chi8: a GPU program for detecting significant interacting SNPs with the Chi-square 8-df test.

    PubMed

    Al-jouie, Abdulrhman; Esfandiari, Mohammadreza; Ramakrishnan, Srividya; Roshan, Usman

    2015-09-14

    Determining interacting SNPs in genome-wide association studies is computationally expensive yet of considerable interest in genomics. We present a program Chi8 that calculates the Chi-square 8 degree of freedom test between all pairs of SNPs in a brute force manner on a Graphics Processing Unit. We analyze each of the seven WTCCC genome-wide association studies that have about 5000 total case and controls and 400,000 SNPs in an average of 9.6 h on a single GPU. We also study the power, false positives, and area under curve of our program on simulated data and provide a comparison to the GBOOST program. Our program source code is freely available from http://www.cs.njit.edu/usman/Chi8.

  16. Clinical Experience with a Single-Nucleotide Polymorphism-Based Noninvasive Prenatal Test for Five Clinically Significant Microdeletions.

    PubMed

    Martin, Kimberly; Iyengar, Sushma; Kalyan, Akshita; Lan, Christine; Simon, Alexander L; Stosic, Melissa; Kobara, Katie; Ravi, Harini; Truong, Tina; Ryan, Allison; Demko, Zachary P; Benn, Peter

    2017-07-11

    Single-nucleotide polymorphism (SNP)-based noninvasive prenatal testing (NIPT) can currently predict a subset of submicroscopic abnormalities associated with severe clinical manifestations. We retrospectively analyzed the performance of SNP-based NIPT in 80,449 referrals for 22q11.2 deletion syndrome and 42,326 referrals for 1p36, cri-du-chat, Prader-Willi, and Angelman microdeletion syndromes over a one-year period, and compared the original screening protocol with a revision that reflexively sequenced high-risk calls at a higher depth of read. The prevalence of these microdeletion syndromes was also estimated in the referral population. The positive predictive value of the original test was 15.7% for 22q11.2 deletion syndrome, and 5.2% for the other four disorders combined. With the revised protocol, these values increased to 44.2% for 22q11.2 and 31.7% for the others. The 0.33% false positive rate for 22q11.2 deletion syndrome decreased to 0.07% with the revised protocol. Similarly, the false positive rate for the other four disorders combined decreased from 0.56% to 0.07%. Minimal prevalences were estimated to be 1/1,255 for 22q11.2 deletion syndrome and 1/1,464 for 1p36, cri-du-chat, and Angelman syndromes combined. Our results show that these microdeletions are relatively common in the referral population, and that the performance of SNP-based NIPT is improved with high-depth resequencing. This article is protected by copyright. All rights reserved.

  17. Rapid testing versus karyotyping in Down's syndrome screening: cost-effectiveness and detection of clinically significant chromosome abnormalities

    PubMed Central

    Gekas, Jean; van den Berg, David-Gradus; Durand, Audrey; Vallée, Maud; Wildschut, Hajo Izaäk Johannes; Bujold, Emmanuel; Forest, Jean-Claude; Rousseau, François; Reinharz, Daniel

    2011-01-01

    In all, 80% of antenatal karyotypes are generated by Down's syndrome screening programmes (DSSP). After a positive screening, women are offered prenatal foetus karyotyping, the gold standard. Reliable molecular methods for rapid aneuploidy diagnosis (RAD: fluorescence in situ hybridization (FISH) and quantitative fluorescence PCR (QF-PCR)) can detect common aneuploidies, and are faster and less expensive than karyotyping. In the UK, RAD is recommended as a standalone approach in DSSP, whereas the US guidelines recommend that RAD be followed up by karyotyping. A cost-effectiveness (CE) analysis of RAD in various DSSP is lacking. There is a debate over the significance of chromosome abnormalities (CA) detected with karyotyping but not using RAD. Our objectives were to compare the CE of RAD versus karyotyping, to evaluate the clinically significant missed CA and to determine the impact of detecting the missed CA. We performed computer simulations to compare six screening options followed by FISH, PCR or karyotyping using a population of 110 948 pregnancies. Among the safer screening strategies, the most cost-effective strategy was contingent screening with QF-PCR (CE ratio of $24 084 per Down's syndrome (DS) detected). Using karyotyping, the CE ratio increased to $27 898. QF-PCR missed only six clinically significant CA of which only one was expected to confer a high risk of an abnormal outcome. The incremental CE ratio (ICER) to find the CA missed by RAD was $66 608 per CA. These costs are much higher than those involved for detecting DS cases. As the DSSP are mainly designed for DS detection, it may be relevant to question the additional costs of karyotyping. PMID:20842178

  18. Rapid testing versus karyotyping in Down's syndrome screening: cost-effectiveness and detection of clinically significant chromosome abnormalities.

    PubMed

    Gekas, Jean; van den Berg, David-Gradus; Durand, Audrey; Vallée, Maud; Wildschut, Hajo Izaäk Johannes; Bujold, Emmanuel; Forest, Jean-Claude; Rousseau, François; Reinharz, Daniel

    2011-01-01

    In all, 80% of antenatal karyotypes are generated by Down's syndrome screening programmes (DSSP). After a positive screening, women are offered prenatal foetus karyotyping, the gold standard. Reliable molecular methods for rapid aneuploidy diagnosis (RAD: fluorescence in situ hybridization (FISH) and quantitative fluorescence PCR (QF-PCR)) can detect common aneuploidies, and are faster and less expensive than karyotyping.In the UK, RAD is recommended as a standalone approach in DSSP, whereas the US guidelines recommend that RAD be followed up by karyotyping. A cost-effectiveness (CE) analysis of RAD in various DSSP is lacking. There is a debate over the significance of chromosome abnormalities (CA) detected with karyotyping but not using RAD. Our objectives were to compare the CE of RAD versus karyotyping, to evaluate the clinically significant missed CA and to determine the impact of detecting the missed CA. We performed computer simulations to compare six screening options followed by FISH, PCR or karyotyping using a population of 110948 pregnancies. Among the safer screening strategies, the most cost-effective strategy was contingent screening with QF-PCR (CE ratio of $24084 per Down's syndrome (DS) detected). Using karyotyping, the CE ratio increased to $27898. QF-PCR missed only six clinically significant CA of which only one was expected to confer a high risk of an abnormal outcome. The incremental CE ratio (ICER) to find the CA missed by RAD was $66608 per CA. These costs are much higher than those involved for detecting DS cases. As the DSSP are mainly designed for DS detection, it may be relevant to question the additional costs of karyotyping.

  19. Inversion of lithium heparin gel tubes after centrifugation is a significant source of bias in clinical chemistry testing.

    PubMed

    Lippi, Giuseppe; Salvagno, Gian Luca; Danese, Elisa; Lima-Oliveira, Gabriel; Brocco, Giorgio; Guidi, Gian Cesare

    2014-09-25

    This study was planned to establish whether random orientation of gel tubes after centrifugation may impair sample quality. Eight gel tubes were collected from 17 volunteers: 2 Becton Dickinson (BD) serum tubes, 2 Terumo serum tubes, 2 BD lithium heparin tubes and 2 Terumo lithium heparin tubes. One patient's tube for each category was kept in a vertical, closure-up position for 90 min ("upright"), whereas paired tubes underwent bottom-up inversion every 15 min, for 90 min ("inverted"). Immediately after this period of time, 14 clinical chemistry analytes, serum indices and complete blood count were then assessed in all tubes. Significant increases were found for phosphate and lipaemic index in all inverted tubes, along with AST, calcium, cholesterol, LDH, potassium, hemolysis index, leukocytes, erythrocytes and platelets limited to lithium heparin tubes. The desirable quality specifications were exceeded for AST, LDH, and potassium in inverted lithium heparin tubes. Residual leukocytes, erythrocytes, platelets and cellular debris were also significantly increased in inverted lithium heparin tubes. Lithium heparin gel tubes should be maintained in a vertical, closure-up position after centrifugation. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Floral signposts: testing the significance of visual ‘nectar guides’ for pollinator behaviour and plant fitness

    PubMed Central

    Hansen, Dennis M.; Van der Niet, Timotheüs; Johnson, Steven D.

    2012-01-01

    Nectar guides, contrasting patterns on flowers that supposedly direct pollinators towards a concealed nectar reward, are taxonomically widespread. However, there have been few studies of their functional significance and effects on plant fitness. Most previous studies focused on pollinator behaviour and used artificial flowers in laboratory settings. We experimentally investigated the role of putative nectar guides in a natural system: the South African iris Lapeirousia oreogena, whose flowers have a clearly visible pattern of six white arrow-markings pointing towards the narrow entrance of the long corolla tube, and its sole pollinator, a long-proboscid nemestrinid fly. We painted over none, some or all of the white arrow-markings with ink that matched the colour of the corolla background. Although arrow-marking removal had little effect on the approaches by flies to flowers from a distance, it dramatically reduced the likelihood of proboscis insertion. Export of pollen dye analogue (an estimate of male fitness) was reduced to almost zero in flowers from which all nectar guides had been removed, and fruit set (a measure of female fitness) was also significantly reduced. Our results confirm that the markings on L. oreogena flowers serve as nectar guides and suggest that they are under strong selective maintenance through both male and female fitness components in this pollination system. PMID:21795269

  1. Significance of iron(II,III) hydroxycarbonate green rust in arsenic remediation using zerovalent iron in laboratory column tests.

    PubMed

    Su, Chunming; Puls, Robert W

    2004-10-01

    We examined the corrosion products of zerovalent iron used in three column tests for removing arsenic from water under dynamic flow conditions. Each column test lasted 3-4 months using columns consisting of a 10.3-cm depth of 50:50 (w:w, Peerless iron:sand) in the middle and a 10.3cm depth of a sediment from Elizabeth City, NC, in both upper and lower portions of the 31-cm-long glass column (2.5 cm in diameter). The feeding solutions were 1 mg of As(V) L(-1) + 1 mg of As(III) L(-1) in 7 mM NaCl + 0.86 mM CaSO4 with or without added phosphate (0.5 or 1 mg of P L(-1)) and silicate (10 or 20 mg of Si L(-1)) at pH 6.5. Iron(II,III) hydroxycarbonate green rust (or simply, carbonate green rust) and magnetite were the major iron corrosion products identified with X-ray diffraction for the separated fractions (5 and 1 min sedimentation and residual). The presence of carbonate green rust was confirmed by scanning electron microscopy (hexagonal morphology) and FTIR-photoacoustic spectroscopy (interlayer carbonate stretching mode at 1352-1365 cm(-1)). X-ray photoelectron spectroscopy investigation revealed the presence of predominantly As(V) at the surface of corroded iron particles despite the fact that the feeding solution in contact with Peerless iron contained more As(III) than As(V) as a result of a preferential uptake of As(V) over As(III) by the Elizabeth City sediment. Extraction of separated corrosion products with 1.0 M HCI showed that from 86 to 96% of the total extractable As (6.9-14.6 g kg(-1)) was in the form of As(V) in agreement with the XPS results. Combined microscopic and macroscopic wet chemistry results suggest that sorbed As(III) was partially oxidized by the carbonate green rust at the early stage of iron corrosion. The column experiments suggest that either carbonate green rust is kinetically favored or is thermodynamically more stable than sulfate green rust in the studied Peerless iron corrosion systems.

  2. Methodological considerations of acoustic playbacks to test the behavioral significance of call directionality in male northern elephant seals (Mirounga angustirostris)

    NASA Astrophysics Data System (ADS)

    Holt, Marla M.; Insley, Stephen J.; Southall, Brandon L.; Schusterman, Ronald J.

    2005-09-01

    While attempting to gain access to receptive females, male northern elephant seals form dominance hierarchies through multiple dyadic interactions involving visual and acoustic signals. These signals are both highly stereotyped and directional. Previous behavioral observations suggested that males attend to the directional cues of these signals. We used in situ vocal playbacks to test whether males attend to directional cues of the acoustic components of a competitors calls (i.e., variation in call spectra and source levels). Here, we will focus on playback methodology. Playback calls were multiple exemplars of a marked dominant male from an isolated area, recorded with a directional microphone and DAT recorder and edited into a natural sequence that controlled call amplitude. Control calls were recordings of ambient rookery sounds with the male calls removed. Subjects were 20 marked males (10 adults and 10 subadults) all located at An~o Nuevo, CA. Playback presentations, calibrated for sound-pressure level, were broadcast at a distance of 7 m from each subject. Most responses were classified into the following categories: visual orientation, postural change, calling, movement toward or away from the loudspeaker, and re-directed aggression. We also investigated developmental, hierarchical, and ambient noise variables that were thought to influence male behavior.

  3. Batch effects correction improves the sensitivity of significance tests in spectral counting-based comparative discovery proteomics.

    PubMed

    Gregori, Josep; Villarreal, Laura; Méndez, Olga; Sánchez, Alex; Baselga, José; Villanueva, Josep

    2012-07-16

    Shotgun proteomics has become the standard proteomics technique for the large-scale measurement of protein abundances in biological samples. Despite quantitative proteomics has been usually performed using label-based approaches, label-free quantitation offers advantages related to the avoidance of labeling steps, no limitation in the number of samples to be compared, and the gain in protein detection sensitivity. However, since samples are analyzed separately, experimental design becomes critical. The exploration of spectral counting quantitation based on LC-MS presented here gathers experimental evidence of the influence of batch effects on comparative proteomics. The batch effects shown with spiking experiments clearly interfere with the biological signal. In order to minimize the interferences from batch effects, a statistical correction is proposed and implemented. Our results show that batch effects can be attenuated statistically when proper experimental design is used. Furthermore, the batch effect correction implemented leads to a substantial increase in the sensitivity of statistical tests. Finally, the applicability of our batch effects correction is shown on two different biomarker discovery projects involving cancer secretomes. We think that our findings will allow designing and executing better comparative proteomics projects and will help to avoid reaching false conclusions in the field of proteomics biomarker discovery. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Environmental Assessment and Finding of No Significant Impact: The Nevada Test Site Development Corporations's Desert Rock Sky Park at the Nevada Test Site

    SciTech Connect

    N /A

    2000-03-01

    The United States Department of Energy has prepared an Environmental Assessment (DOE/EA-1300) (EA) which analyzes the potential environmental effects of developing operating and maintaining a commercial/industrial park in Area 22 of the Nevada Test Site, between Mercury Camp and U.S. Highway 95 and east of Desert Rock Airport. The EA evaluates the potential impacts of infrastructure improvements necessary to support fill build out of the 512-acre Desert Rock Sky Park. Two alternative actions were evaluated: (1) Develop, operate and maintain a commercial/industrial park in Area 22 of the Nevada Test Site, and (2) taking no action. The purpose and need for the commercial industrial park are addressed in Section 1.0 of the EA. A detailed description of the proposed action and alternatives is in section 2.0. Section 3.0 describes the affected environment. Section 4.0 the environmental consequences of the proposed action and alternative. Cumulative effects are addressed in Section 5.0. Mitigation measures are addressed in Section 6.0. The Department of Energy determined that the proposed action of developing, operating and maintaining a commercial/industrial park in Area 22 of the Nevada Test Site would best meet the needs of the agency.

  5. Methodology, results, and significance of an unsaturated-zone tracer test at an artificial-recharge facility, Tucson, Arizona

    USGS Publications Warehouse

    Graham, D.D.

    1989-01-01

    A tracer test conducted in 1987 at an artificial-recharge facility in Tucson, Arizona, indicates that solute movement through the poorly sorted stratified alluvial sediments in the unsaturated zone beneath a recharge basin takes place along preferential-flow paths. Movement of a tracer-laced pulse of reclaimed wastewater was monitored using pressure-vacuum lysimeters installed at depths that range from 11 to 45 ft below the bottom of the recharge basin. Tracer-breakthrough curves do not indicate a consistent relation between maximum tracer concentration and depth or between time of tracer breakthrough and depth. Apparent dispersion, as indicated by the slope of the rising leg of the tracer-breakthrough curve, shows no apparent relation with depth. In some cases, the tracer arrived earlier at deep sampling locations than at shallow ones. Velocity of solute flow ranged from 1.9 to 9.0 ft/day. Less interaction between recharge water and solid-phase materials in the unsaturated zone occurs under preferential-flow conditions than if flow occurred as a uniform wetting front. Flow of water through the unsaturated zone is concentrated into fingers or channels under preferential-flow conditions, and the renovating capability of soil is reduced because of the reduced surface area and reduced contact time in the biologically active part of the unsaturated profile. Chemical substances that normally would be decomposed by microbial activity or sorbed by sediment particles can move through the unsaturated zone and cause groundwater contamination under preferential-flow conditions. (USGS)

  6. The Case for Use of Simple Difference Scores to Test the Significance of Differences in Mean Rates of Change in Controlled Repeated Measurements Designs

    ERIC Educational Resources Information Center

    Overall, John E.; Tonidandel, Scott

    2010-01-01

    A previous Monte Carlo study examined the relative powers of several simple and more complex procedures for testing the significance of difference in mean rates of change in a controlled, longitudinal, treatment evaluation study. Results revealed that the relative powers depended on the correlation structure of the simulated repeated measurements.…

  7. Significant Discrepancies between the Wechsler Adult Intelligence Scale--Revised and the Woodcock-Johnson Psycho-Educational Battery, Part II: Tests of Achievement with a College Population.

    ERIC Educational Resources Information Center

    Salvia, Shawn Amig; Salvia, John

    1986-01-01

    Significant differences were found between college freshmen science (N=50) and nonscience (N=50) majors who were administered the Wechsler Adult Intelligence Scale--Revised (WAIS-R) and the Woodcock-Johnson Psycho-Educational Battery, Part II: Tests of Achievement. (Author/CB)

  8. The Case for Use of Simple Difference Scores to Test the Significance of Differences in Mean Rates of Change in Controlled Repeated Measurements Designs

    ERIC Educational Resources Information Center

    Overall, John E.; Tonidandel, Scott

    2010-01-01

    A previous Monte Carlo study examined the relative powers of several simple and more complex procedures for testing the significance of difference in mean rates of change in a controlled, longitudinal, treatment evaluation study. Results revealed that the relative powers depended on the correlation structure of the simulated repeated measurements.…

  9. Optimization of Deep Drilling Performance - Development and Benchmark Testing of Advanced Diamond Product Drill Bits & HP/HT Fluids to Significantly Improve Rates of Penetration

    SciTech Connect

    Alan Black; Arnis Judzis

    2005-09-30

    This document details the progress to date on the OPTIMIZATION OF DEEP DRILLING PERFORMANCE--DEVELOPMENT AND BENCHMARK TESTING OF ADVANCED DIAMOND PRODUCT DRILL BITS AND HP/HT FLUIDS TO SIGNIFICANTLY IMPROVE RATES OF PENETRATION contract for the year starting October 2004 through September 2005. The industry cost shared program aims to benchmark drilling rates of penetration in selected simulated deep formations and to significantly improve ROP through a team development of aggressive diamond product drill bit--fluid system technologies. Overall the objectives are as follows: Phase 1--Benchmark ''best in class'' diamond and other product drilling bits and fluids and develop concepts for a next level of deep drilling performance; Phase 2--Develop advanced smart bit-fluid prototypes and test at large scale; and Phase 3--Field trial smart bit--fluid concepts, modify as necessary and commercialize products. As of report date, TerraTek has concluded all Phase 1 testing and is planning Phase 2 development.

  10. Prognostic significance of electrical alternans versus signal averaged electrocardiography in predicting the outcome of electrophysiological testing and arrhythmia-free survival

    NASA Technical Reports Server (NTRS)

    Armoundas, A. A.; Rosenbaum, D. S.; Ruskin, J. N.; Garan, H.; Cohen, R. J.

    1998-01-01

    OBJECTIVE: To investigate the accuracy of signal averaged electrocardiography (SAECG) and measurement of microvolt level T wave alternans as predictors of susceptibility to ventricular arrhythmias. DESIGN: Analysis of new data from a previously published prospective investigation. SETTING: Electrophysiology laboratory of a major referral hospital. PATIENTS AND INTERVENTIONS: 43 patients, not on class I or class III antiarrhythmic drug treatment, undergoing invasive electrophysiological testing had SAECG and T wave alternans measurements. The SAECG was considered positive in the presence of one (SAECG-I) or two (SAECG-II) of three standard criteria. T wave alternans was considered positive if the alternans ratio exceeded 3.0. MAIN OUTCOME MEASURES: Inducibility of sustained ventricular tachycardia or fibrillation during electrophysiological testing, and 20 month arrhythmia-free survival. RESULTS: The accuracy of T wave alternans in predicting the outcome of electrophysiological testing was 84% (p < 0.0001). Neither SAECG-I (accuracy 60%; p < 0.29) nor SAECG-II (accuracy 71%; p < 0.10) was a statistically significant predictor of electrophysiological testing. SAECG, T wave alternans, electrophysiological testing, and follow up data were available in 36 patients while not on class I or III antiarrhythmic agents. The accuracy of T wave alternans in predicting the outcome of arrhythmia-free survival was 86% (p < 0.030). Neither SAECG-I (accuracy 65%; p < 0.21) nor SAECG-II (accuracy 71%; p < 0.48) was a statistically significant predictor of arrhythmia-free survival. CONCLUSIONS: T wave alternans was a highly significant predictor of the outcome of electrophysiological testing and arrhythmia-free survival, while SAECG was not a statistically significant predictor. Although these results need to be confirmed in prospective clinical studies, they suggest that T wave alternans may serve as a non-invasive probe for screening high risk populations for malignant ventricular

  11. Prognostic significance of electrical alternans versus signal averaged electrocardiography in predicting the outcome of electrophysiological testing and arrhythmia-free survival

    NASA Technical Reports Server (NTRS)

    Armoundas, A. A.; Rosenbaum, D. S.; Ruskin, J. N.; Garan, H.; Cohen, R. J.

    1998-01-01

    OBJECTIVE: To investigate the accuracy of signal averaged electrocardiography (SAECG) and measurement of microvolt level T wave alternans as predictors of susceptibility to ventricular arrhythmias. DESIGN: Analysis of new data from a previously published prospective investigation. SETTING: Electrophysiology laboratory of a major referral hospital. PATIENTS AND INTERVENTIONS: 43 patients, not on class I or class III antiarrhythmic drug treatment, undergoing invasive electrophysiological testing had SAECG and T wave alternans measurements. The SAECG was considered positive in the presence of one (SAECG-I) or two (SAECG-II) of three standard criteria. T wave alternans was considered positive if the alternans ratio exceeded 3.0. MAIN OUTCOME MEASURES: Inducibility of sustained ventricular tachycardia or fibrillation during electrophysiological testing, and 20 month arrhythmia-free survival. RESULTS: The accuracy of T wave alternans in predicting the outcome of electrophysiological testing was 84% (p < 0.0001). Neither SAECG-I (accuracy 60%; p < 0.29) nor SAECG-II (accuracy 71%; p < 0.10) was a statistically significant predictor of electrophysiological testing. SAECG, T wave alternans, electrophysiological testing, and follow up data were available in 36 patients while not on class I or III antiarrhythmic agents. The accuracy of T wave alternans in predicting the outcome of arrhythmia-free survival was 86% (p < 0.030). Neither SAECG-I (accuracy 65%; p < 0.21) nor SAECG-II (accuracy 71%; p < 0.48) was a statistically significant predictor of arrhythmia-free survival. CONCLUSIONS: T wave alternans was a highly significant predictor of the outcome of electrophysiological testing and arrhythmia-free survival, while SAECG was not a statistically significant predictor. Although these results need to be confirmed in prospective clinical studies, they suggest that T wave alternans may serve as a non-invasive probe for screening high risk populations for malignant ventricular

  12. The Triphenyl Tetrazolium Chloride (Uroscreen) Test Alone and in Combination with the Gram Smear as a Screening Procedure for Significant Bacteriuria in Hospital Patients

    PubMed Central

    Hnatko, S. I.

    1966-01-01

    Of 725 specimens of urine examined by the triphenyl tetrazolium chloride (TTC) [Uroscreen], pour plate and calibrated loop procedures, 30% yielded bacterial colony counts greater than 100,000/ml.; a 100% correlation was obtained among the three methods. Of 539 urine specimens containing more than 100,000 bacteria/ml., 517 (94.06%) gave a positive TTC test. Because of the high correlation between the TTC test and bacterial quantitative counts, the method of TTC in conjunction with smears was adopted as a routine procedure. Specimens which were TTC-negative and smear-negative were discarded. Of 1227 specimens from hospital in-patients and 349 outpatients, 369 urines showed significant bacteriuria (337 from hospital in-patients and 32 from outpatients). There was complete correlation between the TTC test and smear. Of 337 isolations, 27 (8.02%) gave a negative TTC test but a positive smear. PMID:20328583

  13. Score test variable screening

    PubMed Central

    Zhao, Sihai Dave; Li, Yi

    2015-01-01

    Variable screening has emerged as a crucial first step in the analysis of high-throughput data, but existing procedures can be computationally cumbersome, difficult to justify theoretically, or inapplicable to certain types of analyses. Motivated by a high-dimensional censored quantile regression problem in multiple myeloma genomics, this paper makes three contributions. First, we establish a score test-based screening framework, which is widely applicable, extremely computationally efficient, and relatively simple to justify. Secondly, we propose a resampling-based procedure for selecting the number of variables to retain after screening according to the principle of reproducibility. Finally, we propose a new iterative score test screening method which is closely related to sparse regression. In simulations we apply our methods to four different regression models and show that they can outperform existing procedures. We also apply score test screening to an analysis of gene expression data from multiple myeloma patients using a censored quantile regression model to identify high-risk genes. PMID:25124197

  14. The Effectiveness of Noninvasive Biomarkers to Predict Hepatitis B-Related Significant Fibrosis and Cirrhosis: A Systematic Review and Meta-Analysis of Diagnostic Test Accuracy

    PubMed Central

    Xu, Xue-Ying; Kong, Hong; Song, Rui-Xiang; Zhai, Yu-Han; Wu, Xiao-Fei; Ai, Wen-Si; Liu, Hong-Bo

    2014-01-01

    Noninvasive biomarkers have been developed to predict hepatitis B virus (HBV)-related fibrosis owing to the significant limitations of liver biopsy. Those biomarkers were initially derived from evaluation of hepatitis C virus (HCV)-related fibrosis, and their accuracy among HBV-infected patients was under constant debate. A systematic review was conducted on records in PubMed, EMBASE and the Cochrane Library electronic databases, up until April 1st, 2013, in order to systematically assess the effectiveness and accuracy of these biomarkers for predicting HBV-related fibrosis. The questionnaire for quality assessment of diagnostic accuracy studies (QUADAS) was used. Out of 115 articles evaluated for eligibility, 79 studies satisfied the pre-determined inclusion criteria for meta-analysis. Eventually, our final data set for the meta-analysis contained 30 studies. The areas under the SROC curve for APRI, FIB-4, and FibroTest of significant fibrosis were 0.77, 0.75, and 0.84, respectively. For cirrhosis, the areas under the SROC curve for APRI, FIB-4 and FibroTest were 0.75, 0.87, and 0.90, respectively. The heterogeneity of FIB-4 and FibroTest were not statistically significant. The heterogeneity of APRI for detecting significant fibrosis was affected by median age (P = 0.0211), and for cirrhosis was affected by etiology (P = 0.0159). Based on the analysis we claim that FibroTest has excellent diagnostic accuracy for identification of HBV-related significant fibrosis and cirrhosis. FIB-4 has modest benefits and may be suitable for wider scope implementation. PMID:24964038

  15. Significant increase of IGF-I concentration and of IGF-I/IGFBP-3 molar ratio in generation test predicts the good response to growth hormone (GH) therapy in children with short stature and normal results of GH stimulating tests.

    PubMed

    Smyczynska, Joanna; Hilczer, Maciej; Stawerska, Renata; Lewinski, Andrzej

    2013-01-01

    Insulin-like growth factor-I (IGF-I) generation test has been introduced for the assessment of growth hormone (GH) sensitivity, however, its significance in predicting growth response to GH therapy has also been brought up. The molar ratio of IGF-I to its binding protein-3 (IGFBP-3) determines IGF-I bioavailability. Evaluation of usefulness of IGF-I and IGFBP-3 generation test in predicting the effectiveness of rhGH therapy in children with short stature. The analysis comprised 60 children with short stature, normal results of GH stimulating tests but decreased IGF-I secretion. In all the patients, GH insensitivity was excluded on the basis of IGF-I and IGFBP-3 generation test. Next, GH therapy was administered and height velocity (HV), together with IGF-I and IGFBP-3 secretion, was assessed every year, during 3 years. The comparative group consisted of 30 children with partial GH deficiency (pGHD). Both IGF-I secretion and IGF-I/IGFBP-3 molar ratio increased significantly during generation test (p<0.05) and - further - during GH therapy (however insignificantly), together with at least doubling of pretreatment HV. There was no significant difference between the studied group of patients and children with pGHD. Significant increase of IGF-I in generation test speaks for GH therapy effectiveness in short children, despite normal results of GH stimulating tests.

  16. The effect of hearing impairment in older people on the spouse: development and psychometric testing of the significant other scale for hearing disability (SOS-HEAR).

    PubMed

    Scarinci, Nerina; Worrall, Linda; Hickson, Louise

    2009-01-01

    The effects of hearing impairment on the person with the impairment and on their significant others are pervasive and affect the quality of life for all involved. The effect of hearing impairment on significant others is known as a third-party disability. This study aimed to develop and psychometrically test a scale to measure the third-party disability experienced by spouses of older people with hearing impairment. The Significant Other Scale for Hearing Disability (SOS-HEAR) was based on results of a previous qualitative study investigating the effect of hearing impairment on a spouse's everyday life. Psychometric testing with 100 spouses was conducted using item analysis, Cronbach's alpha, factor analysis, and test-retest reliability. Principal components analysis identified six key underlying factors. A combined set of 27 items was found to be reliable (alpha = 0.94), with weighted kappa for items ranging from fair to very good. The SOS-HEAR is a brief, easy to administer instrument that has evidence of reliability and validity. The SOS-HEAR could serve as a means of identifying spouses of older people with hearing impairment in need of intervention, directed towards either the couple or the spouse alone.

  17. Use of the ThinPrep® Imaging System does not alter the frequency of interpreting Papanicolaou tests as atypical squamous cells of undetermined significance

    PubMed Central

    Thrall, Michael J; Russell, Donna K; Bonfiglio, Thomas A; Hoda, Rana S

    2008-01-01

    Background Automated screening of Papanicolaou tests (Pap tests) improves the productivity of cytopathology laboratories. The ThinPrep® Imaging System (TIS) has been widely adopted primarily for this reason for use on ThinPrep® Pap tests (TPPT). However, TIS may also influence the interpretation of Pap tests, leading to changes in the frequency of various interpretive categories. The effect of the TIS on rates of TPPT interpretation as atypical squamous cells of undetermined significance (ASC-US) is of concern because any shift in the frequency of ASC-US will alter the sensitivity and specificity of the Pap test. We have sought to determine whether automated screening of TPPT has altered ASC-US rates in our institution when compared with manual screening (MS) of TPPT. Methods A computerized search for all ASC-US with reflex Human Papillomavirus (HPV) testing over a one-year-period (7/1/06 to 6/30/07) was conducted. Cases included both TPPT screened utilizing TIS and screened manually. HPV test results for both groups were recorded. Pertinent follow-up cervical cytology and histology results were retrieved for the period extending to 11/30/07. Automated screening was in clinical use for 10 months prior to the start of the study. Results Automated screening was performed on 23,103 TPPT, of which 977 (4.23%) were interpreted as ASC-US. Over the same period, MS was performed on 45,789 TPPT, of which 1924 (4.20%) were interpreted as ASC-US. Reflex HPV testing was positive for high risk (HR) types in 47.4% of the TIS cases and 50.2% of MS cases. Follow-up cervical dysplasia found by colposcopy was also distributed proportionally between the two groups. Cervical intraepithelial neoplasia (CIN) was found on follow-up biopsy of 20.1% of the TIS cases (5.2% CIN 2/3) and 21.2% of MS cases (5.1% CIN 2/3). None of these differences were statistically significant. Conclusion Use of the ThinPrep® Imaging System did not appreciably change ASC-US rates or follow-up reflex HPV

  18. The significance of matrix effects on the measurement of lactate dehydrogenase (LD) activity using Kodak dry slide technology in the Ontario Laboratory Proficiency Testing Program.

    PubMed

    Hill, S A; Heathcote, J C; McQueen, M J

    1990-04-01

    A recent lactate dehydrogenase (LD) survey of the Laboratory Proficiency Testing Program (LPTP) of Ontario showed interlaboratory coefficients of variation ranging from 6.5% to 40% for five lyophilized vials on the 12 Kodak analyzers. All the LPTP survey samples had similar protein and LD isoenzyme electrophoretic patterns which remained unchanged after reconstitution and storage for 5 days at 4 degrees C, although the total LD activities fell. Four Ektachem 700 analyzers were subsequently tested using LPTP material and no difference in LD activity between instruments or between two LD slide lot numbers was shown. Generation 9 slides gave higher LD activities than generation 10 on all the reconstituted lyophilized proficiency testing samples. There was no significant difference between slide generations when 19 liquid human sera were analyzed, indicating that the variability on LPTP samples was due to a matrix effect. Definition of the matrix effect of lyophilized proficiency testing material is essential before any proficiency testing program can use such material to reflect analytical performance on patient specimens.

  19. Significance of a negative exercise thallium test in the presence of a critical residual stenosis after thrombolysis for acute myocardial infarction

    SciTech Connect

    Sutton, J.M.; Topol, E.J. )

    1991-04-01

    After thrombolytic therapy for acute myocardial infarction, increasing emphasis is placed on early submaximal exercise testing, with further intervention advocated only for demonstrable ischemia. Although significant residual coronary artery lesions after successful thrombolysis are common, many patients paradoxically have no corresponding provokable ischemia. The relation between significant postthrombolytic residual coronary artery disease and a negative early, submaximal exercise thallium-201 tomogram was studied among 101 consecutive patients with uncomplicated myocardial infarction and at least 70% residual stenosis of the infarct artery. A negative test occurred in 49 (48.5%) patients with a mean 88% residual infarct artery stenosis. Further characteristics of the group were as follows: mean time to treatment was 3.1 hours; mean age was 54 +/- 10 years; 80% were male; 47% had anterior infarction; 39% had multivessel disease; mean left ventricular ejection fraction was 53 +/- 14%; and mean peak creatine kinase level was 3,820 +/- 3,123 IU/ml. A similar group of 52 (51.5%) patients, treated within 3.3 hours from symptom onset, with a mean postthrombolysis stenosis of 90%, had a positive exercise test. Characteristics of this group were as follows: age was 58 +/- 10 years; 92% were male; 56% had anterior infarction; 40% had multivessel disease; and mean left ventricular ejection fraction was 54 +/- 15%. The peak creatine kinase level associated with the infarction, however, was lower: 2,605 +/- 1,805 IU/ml (p = 0.04). There was no difference in performance at exercise testing with respect to peak systolic pressure, peak heart rate, or time tolerated on the treadmill between the two groups. By multivariate logistic regression, only peak creatine kinase level predicted a negative stress result in the presence of a significant residual stenosis.

  20. Optimization of Deep Drilling Performance--Development and Benchmark Testing of Advanced Diamond Product Drill Bits & HP/HT Fluids to Significantly Improve Rates of Penetration

    SciTech Connect

    Alan Black; Arnis Judzis

    2003-10-01

    This document details the progress to date on the OPTIMIZATION OF DEEP DRILLING PERFORMANCE--DEVELOPMENT AND BENCHMARK TESTING OF ADVANCED DIAMOND PRODUCT DRILL BITS AND HP/HT FLUIDS TO SIGNIFICANTLY IMPROVE RATES OF PENETRATION contract for the year starting October 2002 through September 2002. The industry cost shared program aims to benchmark drilling rates of penetration in selected simulated deep formations and to significantly improve ROP through a team development of aggressive diamond product drill bit--fluid system technologies. Overall the objectives are as follows: Phase 1--Benchmark ''best in class'' diamond and other product drilling bits and fluids and develop concepts for a next level of deep drilling performance; Phase 2--Develop advanced smart bit--fluid prototypes and test at large scale; and Phase 3--Field trial smart bit--fluid concepts, modify as necessary and commercialize products. Accomplishments to date include the following: 4Q 2002--Project started; Industry Team was assembled; Kick-off meeting was held at DOE Morgantown; 1Q 2003--Engineering meeting was held at Hughes Christensen, The Woodlands Texas to prepare preliminary plans for development and testing and review equipment needs; Operators started sending information regarding their needs for deep drilling challenges and priorities for large-scale testing experimental matrix; Aramco joined the Industry Team as DEA 148 objectives paralleled the DOE project; 2Q 2003--Engineering and planning for high pressure drilling at TerraTek commenced; 3Q 2003--Continuation of engineering and design work for high pressure drilling at TerraTek; Baker Hughes INTEQ drilling Fluids and Hughes Christensen commence planning for Phase 1 testing--recommendations for bits and fluids.

  1. Functional (13)C-urea and glucose hydrogen/methane breath tests reveal significant association of small intestinal bacterial overgrowth in individuals with active Helicobacter pylori infection.

    PubMed

    Enko, Dietmar; Kriegshäuser, Gernot

    2017-01-01

    Helicobacter pylori infection is considered to alter the bacterial flora in the upper gastrointestinal tract. This study aimed at investigating the presence of small intestinal bacterial overgrowth (SIBO) in patients with active H. pylori infection assessed by functional breath testing. A total of 109 outpatients, who were referred for the H. pylori(13)C-urea breath test ((13)C-UBT) by general practitioners and specialists, were also tested for the presence of SIBO by the glucose hydrogen (H2)/methane (CH4) breath test (HMBT). A detailed anamnesis was carried out about the history of H. pylori infection, eradication therapies, proton pump inhibitor intake, and comorbidities. In total, 36/109 (33.0%) patients had a positive H. pylori(13)C-UBT, and 35/109 (32.1%) patients had a positive glucose HMBT, the latter being indicative of SIBO. Interestingly, individuals with a positive H. pylori(13)C-UBT were significantly more often associated with a positive glucose HMBT (p=0.002). Cohen's κ measuring agreement between the (13)C-UBT and the glucose HMBT was 0.31 (confidence intervals: 0.12-0.50) (p=0.001). Altogether, 19 of 54 (35.2%) patients, who had completed up to four eradication therapies, were diagnosed with SIBO by HMBT. H. pylori infection was found to be significantly associated with the presence of SIBO as determined by functional breath testing. In addition, SIBO rates appeared to have increased after completed eradication therapies. However, further longitudinal studies are warranted to fully elucidate the relationship and treatment modalities of coincident H. pylori infection and SIBO. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  2. A new direction for prenatal chromosome microarray testing: software-targeting for detection of clinically significant chromosome imbalance without equivocal findings

    PubMed Central

    Bint, Susan; Irving, Melita D.; Kyle, Phillipa M.; Akolekar, Ranjit; Mohammed, Shehla N.; Mackie Ogilvie, Caroline

    2014-01-01

    Purpose. To design and validate a prenatal chromosomal microarray testing strategy that moves away from size-based detection thresholds, towards a more clinically relevant analysis, providing higher resolution than G-banded chromosomes but avoiding the detection of copy number variants (CNVs) of unclear prognosis that cause parental anxiety. Methods. All prenatal samples fulfilling our criteria for karyotype analysis (n = 342) were tested by chromosomal microarray and only CNVs of established deletion/duplication syndrome regions and any other CNV >3 Mb were detected and reported. A retrospective full-resolution analysis of 249 of these samples was carried out to ascertain the performance of this testing strategy. Results. Using our prenatal analysis, 23/342 (6.7%) samples were found to be abnormal. Of the remaining samples, 249 were anonymized and reanalyzed at full-resolution; a further 46 CNVs were detected in 44 of these cases (17.7%). None of these additional CNVs were of clear clinical significance. Conclusion. This prenatal chromosomal microarray strategy detected all CNVs of clear prognostic value and did not miss any CNVs of clear clinical significance. This strategy avoided both the problems associated with interpreting CNVs of uncertain prognosis and the parental anxiety that are a result of such findings. PMID:24795849

  3. OPTIMIZATION OF DEEP DRILLING PERFORMANCE--DEVELOPMENT AND BENCHMARK TESTING OF ADVANCED DIAMOND PRODUCT DRILL BITS & HP/HT FLUIDS TO SIGNIFICANTLY IMPROVE RATES OF PENETRATION

    SciTech Connect

    Alan Black; Arnis Judzis

    2004-10-01

    The industry cost shared program aims to benchmark drilling rates of penetration in selected simulated deep formations and to significantly improve ROP through a team development of aggressive diamond product drill bit--fluid system technologies. Overall the objectives are as follows: Phase 1--Benchmark ''best in class'' diamond and other product drilling bits and fluids and develop concepts for a next level of deep drilling performance; Phase 2--Develop advanced smart bit-fluid prototypes and test at large scale; and Phase 3--Field trial smart bit-fluid concepts, modify as necessary and commercialize products. As of report date, TerraTek has concluded all major preparations for the high pressure drilling campaign. Baker Hughes encountered difficulties in providing additional pumping capacity before TerraTek's scheduled relocation to another facility, thus the program was delayed further to accommodate the full testing program.

  4. Detection of coronary artery disease in postmenopausal women: the significance of integrated stress imaging tests in a 4-year prognostic study.

    PubMed

    Becker, Michael; Hundemer, Anne; Zwicker, Christian; Altiok, Ertunc; Krohn, Thomas; Mottaghy, Felix M; Lente, Christina; Kelm, Malte; Marx, Nikolaus; Hoffmann, Rainer

    2015-03-01

    The present prospective study investigated whether a combined approach integrating two different stress imaging modalities may improve the diagnostic accuracy and prognostic impact of non-invasive coronary artery disease (CAD) tests in postmenopausal women. In women non-invasive tests for detecting CAD are less accurate than in men, leading to a high proportion of unnecessary coronary angiographies (CAs). 424 consecutive postmenopausal women (mean 61 ± 7 years, mean Reynolds Risk Score 13 ± 3 %) with symptoms suggestive of CAD were prospectively included and followed up for 4 ± 1 years. Each patient underwent CA, stress cardiovascular magnetic resonance (CMR) by adenosine, dobutamine stress echocardiography (DSE) and single-photon emission computed tomography (SPECT) within 7 ± 3 days. Anatomically obstructive coronary artery disease (≥50 % diameter stenosis) was present in 157 women (37 %). The combination of two stress imaging modalities significantly increased the positive predictive values (PPV) to 90 ± 3, 88 ± 3 and 87 ± 2 % for CMR/DSE, DSE/SPECT and CMR/SPECT, respectively. For patients with negative combined test results, the survival analysis showed a 4-year cumulative event-free survival rate of 96-97 % for all combinations. This new approach is cost effective due to the resulting reduction in unnecessary CAs (with potential side effects and corresponding therapies) as well as reducing hospitalization time. In symptomatic postmenopausal women, combination of two negative stress imaging results significantly increases the PPV for detection of CAD and excludes future cardiovascular events with high accuracy. This approach may be applied to improve the prognostic precision of non-invasive CAD tests and to avoid unnecessary CAs.

  5. A puzzle form of a non-verbal intelligence test gives significantly higher performance measures in children with severe intellectual disability.

    PubMed

    Bello, Katrina D; Goharpey, Nahal; Crewther, Sheila G; Crewther, David P

    2008-08-01

    Assessment of 'potential intellectual ability' of children with severe intellectual disability (ID) is limited, as current tests designed for normal children do not maintain their interest. Thus a manual puzzle version of the Raven's Coloured Progressive Matrices (RCPM) was devised to appeal to the attentional and sensory preferences and language limitations of children with ID. It was hypothesized that performance on the book and manual puzzle forms would not differ for typically developing children but that children with ID would perform better on the puzzle form. The first study assessed the validity of this puzzle form of the RCPM for 76 typically developing children in a test-retest crossover design, with a 3 week interval between tests. A second study tested performance and completion rate for the puzzle form compared to the book form in a sample of 164 children with ID. In the first study, no significant difference was found between performance on the puzzle and book forms in typically developing children, irrespective of the order of completion. The second study demonstrated a significantly higher performance and completion rate for the puzzle form compared to the book form in the ID population. Similar performance on book and puzzle forms of the RCPM by typically developing children suggests that both forms measure the same construct. These findings suggest that the puzzle form does not require greater cognitive ability but demands sensory-motor attention and limits distraction in children with severe ID. Thus, we suggest the puzzle form of the RCPM is a more reliable measure of the non-verbal mentation of children with severe ID than the book form.

  6. Development and validation of a nomogram based on clinical factors and standard laboratory tests for prediction of clinically significant liver fibrosis in chronic hepatitis C virus infection.

    PubMed

    Sagrini, Elisabetta; Ardoino, Ilaria; Marano, Giuseppe; Gianstefani, Alice; Orlandini, Alessandra; Sebastiani, Giada; Donati, Gabriele; Cucchetti, Alessandro; Pelosi, Guido; Ferrari, Carlo; Alberti, Alfredo; Biganzoli, Elia; Piscaglia, Fabio; Bolondi, Luigi

    2013-12-01

    Staging liver fibrosis in chronic viral hepatitis C (HCV) patients is essential for prompting surveillance and treatment. The aim of this study was to develop a nomogram, on the basis of simple clinical and laboratory variables, to predict three clinically significant stages of fibrosis (nil-mild, moderate, advanced/cirrhosis), using histology as reference, and to compare its performance with that of FibroTest, a widely used noninvasive fibrosis score. Nomograms are graphical representations of a mathematical formula, used as predictive tools. The study retrospectively recruited 406 HCV patients undergoing liver biopsy. Nomogram was developed in a training set of 252 patients and tested in a validation set of 154 patients. Histology was staged according to the Metavir system. Fibrosis stages were subgrouped as follows: advanced fibrosis/cirrhosis (F3/F4, 24%), nil-mild (F0/F1, 36%), and moderate (F2, 40%). Age at biopsy, aspartate aminotransferase, γ-glutamyl transpeptidase, albumin, platelet count, and prothrombin activity formed the basis for the so-called Fibro-Nomogram, which, in one graphical representation, estimates probability for different stages of fibrosis. Areas under the receiver-operating characteristic curves for advanced fibrosis/cirrhosis were similar for training (0.86) and validation sets (0.87). For nil-mild fibrosis, area under the receiver-operating characteristics were 0.81 and 0.79. Compared with FibroTest, Fibro-Nomogram performed slightly better at predicting severe fibrosis (F3/F4) with positive likelihood ratio (LR+) 5.07 (95% confidence interval 3.08-8.37) versus LR+ 3.82 (95% confidence interval 2.56-5.71) for FibroTest. For nil-mild fibrosis, the two tests showed limited but comparable performances. In HCV patients, Fibro-Nomogram, an inexpensive and readily available predictive tool, could enable clinicians to interpret patients' profile, concurrently stratifying patients into three clinically relevant probability categories with

  7. Clinical Significance of an HPV DNA Chip Test with Emphasis on HPV-16 and/or HPV-18 Detection in Korean Gynecological Patients.

    PubMed

    Yeo, Min-Kyung; Lee, Ahwon; Hur, Soo Young; Park, Jong Sup

    2016-07-01

    Human papillomavirus (HPV) is a major risk factor for cervical cancer. We evaluated the clinical significance of the HPV DNA chip genotyping assay (MyHPV chip, Mygene Co.) compared with the Hybrid Capture 2 (HC2) chemiluminescent nucleic acid hybridization kit (Digene Corp.) in 867 patients. The concordance rate between the MyHPV chip and HC2 was 79.4% (kappa coefficient, κ = 0.55). The sensitivity and specificity of both HPV tests were very similar (approximately 85% and 50%, respectively). The addition of HPV result (either MyHPV chip or HC2) to cytology improved the sensitivity (95%, each) but reduced the specificity (approximately 30%, each) compared with the HPV test or cytology alone. Based on the MyHPV chip results, the odds ratio (OR) for ≥ high-grade squamous intraepithelial lesions (HSILs) was 9.9 in the HPV-16/18 (+) group and 3.7 in the non-16/18 high-risk (HR)-HPV (+) group. Based on the HC2 results, the OR for ≥ HSILs was 5.9 in the HR-HPV (+) group. When considering only patients with cytological diagnoses of "negative for intraepithelial lesion or malignancy" and "atypical squamous cell or atypical glandular cell," based on the MyHPV chip results, the ORs for ≥ HSILs were 6.8 and 11.7, respectively, in the HPV-16/18 (+) group. The sensitivity and specificity of the MyHPV chip test are similar to the HC2. Detecting HPV-16/18 with an HPV DNA chip test, which is commonly used in many Asian countries, is useful in assessing the risk of high-grade cervical lesions.

  8. The significance of mouse liver tumor formation for carcinogenic risk assessment: results and conclusions from a survey of ten years of testing by the agrochemical industry.

    PubMed Central

    Carmichael, N G; Enzmann, H; Pate, I; Waechter, F

    1997-01-01

    A survey was performed on the results of 138 carcinogenicity studies conducted in various mouse strains by the agrochemical industry over the period 1983-1993. Data for liver tumor incidence, liver weight, and histopathology were collected along with data on genotoxicity. Studies were judged positive or negative for liver tumor formation on the basis of apparent dose response, malignancy, and difference from historical control values using a weight of evidence approach. Thirty-seven studies were judged to be positive for liver tumorigenicity in one or both sexes. There was no evidence showing an influence of the mouse strain and the duration of the study on the proportion of positive studies. Although 8 of the chemicals tested in the 138 studies were positive in the Ames test, only one of these was judged positive for carcinogenicity. Only 6 of the 37 positive chemicals had any other reported positive genotoxicity findings. A clear relationship between hepatomegaly at 1 year after exposure and a positive tumorigenic outcome at 18 months or 2 years after exposure was demonstrated. Whereas the average relative liver weight of top dose animals was 110% of control in negative studies, it was 150% in positive studies. Likewise, very few negative studies demonstrated significant pathological findings after 1 year, whereas the majority of positive studies had significant liver pathology. The implications of these findings for extrapolation to humans are discussed. Images p1196-a Figure 1. A Figure 1. B Figure 1. C Figure 1. D Figure 2. A Figure 2. B Figure 2. C Figure 2. D Figure 3. Figure 3. Figure 4. Figure 4. PMID:9370513

  9. Evaluating the effective numbers of independent tests and significant p-value thresholds in commercial genotyping arrays and public imputation reference datasets.

    PubMed

    Li, Miao-Xin; Yeung, Juilian M Y; Cherny, Stacey S; Sham, Pak C

    2012-05-01

    Current genome-wide association studies (GWAS) use commercial genotyping microarrays that can assay over a million single nucleotide polymorphisms (SNPs). The number of SNPs is further boosted by advanced statistical genotype-imputation algorithms and large SNP databases for reference human populations. The testing of a huge number of SNPs needs to be taken into account in the interpretation of statistical significance in such genome-wide studies, but this is complicated by the non-independence of SNPs because of linkage disequilibrium (LD). Several previous groups have proposed the use of the effective number of independent markers (M(e)) for the adjustment of multiple testing, but current methods of calculation for M(e) are limited in accuracy or computational speed. Here, we report a more robust and fast method to calculate M(e). Applying this efficient method [implemented in a free software tool named Genetic type 1 error calculator (GEC)], we systematically examined the M(e), and the corresponding p-value thresholds required to control the genome-wide type 1 error rate at 0.05, for 13 Illumina or Affymetrix genotyping arrays, as well as for HapMap Project and 1000 Genomes Project datasets which are widely used in genotype imputation as reference panels. Our results suggested the use of a p-value threshold of ~10(-7) as the criterion for genome-wide significance for early commercial genotyping arrays, but slightly more stringent p-value thresholds ~5 × 10(-8) for current or merged commercial genotyping arrays, ~10(-8) for all common SNPs in the 1000 Genomes Project dataset and ~5 × 10(-8) for the common SNPs only within genes.

  10. Significance Testing Needs a Taxonomy: Or How the Fisher, Neyman-Pearson Controversy Resulted in the Inferential Tail Wagging the Measurement Dog.

    PubMed

    Bradley, Michael T; Brand, Andrew

    2016-10-01

    Accurate measurement and a cutoff probability with inferential statistics are not wholly compatible. Fisher understood this when he developed the F test to deal with measurement variability and to make judgments on manipulations that may be worth further study. Neyman and Pearson focused on modeled distributions whose parameters were highly determined and concluded that inferential judgments following an F test could be made with accuracy because the distribution parameters were determined. Neyman and Pearson's approach in the application of statistical analyses using alpha and beta error rates has played a dominant role guiding inferential judgments, appropriately in highly determined situations and inappropriately in scientific exploration. Fisher tried to explain the different situations, but, in part due to some obscure wording, generated a long standing dispute that currently has left the importance of Fisher's p < .05 criteria not fully understood and a general endorsement of the Neyman and Pearson error rate approach. Problems were compounded with power calculations based on effect sizes following significant results entering into exploratory science. To understand in a practical sense when each approach should be used, a dimension reflecting varying levels of certainty or knowledge of population distributions is presented. The dimension provides a taxonomy of statistical situations and appropriate approaches by delineating four zones that represent how well the underlying population of interest is defined ranging from exploratory situations to highly determined populations. © The Author(s) 2016.

  11. Consomic mouse strain selection based on effect size measurement, statistical significance testing and integrated behavioral z-scoring: focus on anxiety-related behavior and locomotion.

    PubMed

    Labots, M; Laarakker, M C; Ohl, F; van Lith, H A

    2016-06-29

    Selecting chromosome substitution strains (CSSs, also called consomic strains/lines) used in the search for quantitative trait loci (QTLs) consistently requires the identification of the respective phenotypic trait of interest and is simply based on a significant difference between a consomic and host strain. However, statistical significance as represented by P values does not necessarily predicate practical importance. We therefore propose a method that pays attention to both the statistical significance and the actual size of the observed effect. The present paper extends on this approach and describes in more detail the use of effect size measures (Cohen's d, partial eta squared - η p (2) ) together with the P value as statistical selection parameters for the chromosomal assignment of QTLs influencing anxiety-related behavior and locomotion in laboratory mice. The effect size measures were based on integrated behavioral z-scoring and were calculated in three experiments: (A) a complete consomic male mouse panel with A/J as the donor strain and C57BL/6J as the host strain. This panel, including host and donor strains, was analyzed in the modified Hole Board (mHB). The consomic line with chromosome 19 from A/J (CSS-19A) was selected since it showed increased anxiety-related behavior, but similar locomotion compared to its host. (B) Following experiment A, female CSS-19A mice were compared with their C57BL/6J counterparts; however no significant differences and effect sizes close to zero were found. (C) A different consomic mouse strain (CSS-19PWD), with chromosome 19 from PWD/PhJ transferred on the genetic background of C57BL/6J, was compared with its host strain. Here, in contrast with CSS-19A, there was a decreased overall anxiety in CSS-19PWD compared to C57BL/6J males, but not locomotion. This new method shows an improved way to identify CSSs for QTL analysis for anxiety-related behavior using a combination of statistical significance testing and effect

  12. Significant heat sensitivity increase detected in various types of diabetes mellitus patients by Akabane test for use of management of diabetic patients.

    PubMed

    Muzhikov, Valery; Vershinina, Elena; Belenky, Vadim; Muzhikov, Ruslan

    2016-01-01

    In order to assess patterns of heat sensitivity thresholds in patients with diabetes mellitus, the Akabane test was carried out on patients with insulin dependent diabetes mellitus (IDDM) (250 men and 309 women) and patients with noninsulin dependent diabetes mellitus (NIDDM) (158 men and 227 women). For comparison, a group of healthy subjects made up of 116 men and 277 women was also used. As soon as we revealed the influence of factors of pathology with a high significance level and gender and the interaction "gender*pathology", all the results are described separately for groups of men and women and for groups with IDDM and NIDDM. Simple effects of paired comparisons between healthy subjects, IDDM and NIDDM in groups of men and women, as well as comparisons between the profiles of men and women with IDDM and NIDDM showed significant differences between ACs in healthy subjects and those with each type of diabetes. The most significant differences are seen in the AC connected with the digestive system (SP pancreas channel), LR (liver channel), ST (stomach channel), GB (gall bladder channel). Thus, we revealed characteristic pattern of acupuncture channels (AC) lesions inherent to diabetes pathology, i.e. most vulnerable in diabetes ACs, being compromised in dependence from such factors, as type of diabetes, hyper or hypoglycemia, and from gender. The main value of the method lies in the fact that we observe the entire food chain from food ingestion to the utilization of carbohydrates with the opportunity to assess the activity of each organ and its regulatory contribution. On the basis of the body's response, an individual selection of medicines can be made, and by evaluating the individual biorhythms it is possible to determine the optimal time of administration.

  13. Evolutionary significance of geographic variation in a plumage-based foraging adaptation: an experimental test in the slate-throated redstart (Myioborus miniatus).

    PubMed

    Mumme, Ronald L; Galatowitsch, Mark L; Jabłoński, Piotr G; Stawarczyk, Tadeusz M; Cygan, Jakub P

    2006-05-01

    Geographic variation in the plumage pattern of birds is widespread but poorly understood, and in very few cases has its evolutionary significance been investigated experimentally. Neotropical warblers of the genus Myioborus use their contrasting black-and-white plumage to flush insect prey during animated foraging displays. Although previous experimental work has demonstrated that white plumage patches are critical to flush-pursuit foraging success, the amount of white in the plumage shows considerable interspecific and intraspecific geographic variation. We investigated the evolutionary significance of this geographic variation by experimentally decreasing or increasing the amount of white in the tail of slate-throated redstarts (Myioborus miniatus comptus) from Monteverde, Costa Rica, to mimic the natural extremes of tail pattern variation in this species. In addition to measuring the effects of plumage manipulation on foraging performance, we performed field experiments measuring the escape response of a common insect prey species (an asilid fly) using model redstarts representing four different Myioborus plumage patterns. Our experiments were designed to test four hypotheses that could explain geographic variation in plumage pattern. Compared to controls, experimental birds with reduced-white tails that mimic the plumage pattern of M. miniatus hellmayri of Guatemala showed significant reductions in flush-pursuit foraging performance. In contrast, the addition of white to the tail to mimic the plumage pattern of M. miniatus verticalis of Bolivia had no significant effect on foraging performance of Costa Rican redstarts. In field experiments with asilid flies, model redstarts simulating the plumage of M. miniatus comptus of Costa Rica and M. miniatus verticalis of Bolivia elicited greater responses than did models of other Myioborus taxa with either less or more white in the plumage. The results of our experiments with both birds and insects allow us to reject

  14. Significant lexical relationships

    SciTech Connect

    Pedersen, T.; Kayaalp, M.; Bruce, R.

    1996-12-31

    Statistical NLP inevitably deals with a large number of rare events. As a consequence, NLP data often violates the assumptions implicit in traditional statistical procedures such as significance testing. We describe a significance test, an exact conditional test, that is appropriate for NLP data and can be performed using freely available software. We apply this test to the study of lexical relationships and demonstrate that the results obtained using this test are both theoretically more reliable and different from the results obtained using previously applied tests.

  15. Relationship Between the Presence of Eczema Herpeticum and the Significance of Clinical and Laboratory Tests in Korean Children With Atopic Dermatitis

    PubMed Central

    Kim, Kohwoon; Kang, Junseok; Won Kim, Sung; Sung, Myongsoon

    2016-01-01

    Background Eczema herpeticum (EH) is a herpes simplex virus (HSV) infection superimposed on atopic dermatitis (AD). Objectives The aim of this study was to evaluate the relationship between clinical features and laboratory tests, including skin cultures, total IgE, eosinophil count, eosinophil cationic protein, and 25-hydroxyvitamin D3 (25-(OH)D3), in Korean children with AD according to the presence of EH. Patients and Methods We enrolled 380 patients aged 6 months to 18 years who were admitted to Busan St. Mary’s hospital from January 2012 to December 2014. All 380 subjects were divided into two groups: the control and the AD group. The AD group was further divided into two subgroups: EH+ and EH-. Results The male gender was related to the presence of EH (odds ratio of 2.56; 95% confidence interval, 1.19 - 5.53, P = 0.01), but age and 25-(OH)D3 levels were not. After adjusting for age, gender, and 25-(OH)D3, no significant relationship was found between total IgE, eosinophil cationic protein or eosinophil count levels and the presence of EH. The relationship between positive skin cultures and the presence of EH was significant (P < 0.001) and the presence of methicillin-resistant Staphylococcus aureus (MRSA) was also related to the development of EH (OR, 0.19; 95% CI, 0.04 - 0.92, P = 0.03). Conclusions We conclude that while male gender, positive skin culture results, and the presence of MRSA are factors influencing EH, serum 25-(OH)D3 levels are not associated with EH in Korean AD children. PMID:27713812

  16. Co-Educational Tutorial Classes and Their Significance on Gendered Test Scores of Wollo University Students: A Before-After Analyses

    ERIC Educational Resources Information Center

    Gidey, Mu'uz

    2015-01-01

    This action research is carried out in a practical class room setting to devise an innovative way of administering tutorial classes to improve students' learning competence with particular reference to gendered test scores. A before-after test score analyses of mean and standard deviations along with t-statistical tests of hypotheses of second…

  17. A resampling-based Markovian model for automated colon cancer diagnosis.

    PubMed

    Ozdemir, Erdem; Sokmensuer, Cenk; Gunduz-Demir, Cigdem

    2012-01-01

    In recent years, there has been a great effort in the research of implementing automated diagnostic systems for tissue images. One major challenge in this implementation is to design systems that are robust to image variations. In order to meet this challenge, it is important to learn the systems on a large number of labeled images from a different range of variation. However, acquiring labeled images is quite difficult in this domain, and hence, the labeled training data are typically very limited. Although the issue of having limited labeled data is acknowledged by many researchers, it has rarely been considered in the system design. This paper successfully addresses this issue, introducing a new resampling framework to simulate variations in tissue images. This framework generates multiple sequences from an image for its representation and models them using a Markov process. Working with colon tissue images, our experiments show that this framework increases the generalization capacity of a learner by increasing the size and variation of the training data and improves the classification performance of a given image by combining the decisions obtained on its sequences.

  18. Resampling-Based Gap Analysis for Detecting Nodes with High Centrality on Large Social Network

    DTIC Science & Technology

    2015-05-22

    Hiroshi Motoda4,5 1 Department of Integrated Information Technology, Aoyama Gakuin University, Kanagawa, Japan ohara@it.aoyama.ac.jp 2 School of...Administration and Informatics, University of Shizuoka, Shizuoka, Japan k-saito@u-shizuoka-ken.ac.jp 3 Department of Electronics and Informatics, Ryukoku...University, Shiga, Japan kimura@rins.ryukoku.ac.jp 4 Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan 5 School of

  19. Correcting the optimal resampling-based error rate by estimating the error rate of wrapper algorithms.

    PubMed

    Bernau, Christoph; Augustin, Thomas; Boulesteix, Anne-Laure

    2013-09-01

    High-dimensional binary classification tasks, for example, the classification of microarray samples into normal and cancer tissues, usually involve a tuning parameter. By reporting the performance of the best tuning parameter value only, over-optimistic prediction errors are obtained. For correcting this tuning bias, we develop a new method which is based on a decomposition of the unconditional error rate involving the tuning procedure, that is, we estimate the error rate of wrapper algorithms as introduced in the context of internal cross-validation (ICV) by Varma and Simon (2006, BMC Bioinformatics 7, 91). Our subsampling-based estimator can be written as a weighted mean of the errors obtained using the different tuning parameter values, and thus can be interpreted as a smooth version of ICV, which is the standard approach for avoiding tuning bias. In contrast to ICV, our method guarantees intuitive bounds for the corrected error. Additionally, we suggest to use bias correction methods also to address the conceptually similar method selection bias that results from the optimal choice of the classification method itself when evaluating several methods successively. We demonstrate the performance of our method on microarray and simulated data and compare it to ICV. This study suggests that our approach yields competitive estimates at a much lower computational price.

  20. Numerical study identifying the factors causing the significant underestimation of the specific discharge estimated using the modified integral pumping test method in a laboratory experiment.

    PubMed

    Sun, Kerang

    2015-09-01

    A three-dimensional finite element model is constructed to simulate the experimental conditions presented in a paper published in this journal [Goltz et al., 2009. Validation of two innovative methods to measure contaminant mass flux in groundwater. Journal of Contaminant Hydrology 106 (2009) 51-61] where the modified integral pumping test (MIPT) method was found to significantly underestimate the specific discharge in an artificial aquifer. The numerical model closely replicates the experimental configuration with explicit representation of the pumping well column and skin, allowing for the model to simulate the wellbore flow in the pumping well as an integral part of the porous media flow in the aquifer using the equivalent hydraulic conductivity approach. The equivalent hydraulic conductivity is used to account for head losses due to friction within the wellbore of the pumping well. Applying the MIPT method on the model simulated piezometric heads resulted in a specific discharge that underestimates the true specific discharge in the experimental aquifer by 18.8%, compared with the 57% underestimation of mass flux by the experiment reported by Goltz et al. (2009). Alternative simulation shows that the numerical model is capable of approximately replicating the experiment results when the equivalent hydraulic conductivity is reduced by an order of magnitude, suggesting that the accuracy of the MIPT estimation could be improved by expanding the physical meaning of the equivalent hydraulic conductivity to account for other factors such as orifice losses in addition to frictional losses within the wellbore. Numerical experiments also show that when applying the MIPT method to estimate hydraulic parameters, use of depth-integrated piezometric head instead of the head near the pump intake can reduce the estimation error resulting from well losses, but not the error associated with the well not being fully screened.

  1. Numerical study identifying the factors causing the significant underestimation of the specific discharge estimated using the modified integral pumping test method in a laboratory experiment

    NASA Astrophysics Data System (ADS)

    Sun, Kerang

    2015-09-01

    A three-dimensional finite element model is constructed to simulate the experimental conditions presented in a paper published in this journal [Goltz et al., 2009. Validation of two innovative methods to measure contaminant mass flux in groundwater. Journal of Contaminant Hydrology 106 (2009) 51-61] where the modified integral pumping test (MIPT) method was found to significantly underestimate the specific discharge in an artificial aquifer. The numerical model closely replicates the experimental configuration with explicit representation of the pumping well column and skin, allowing for the model to simulate the wellbore flow in the pumping well as an integral part of the porous media flow in the aquifer using the equivalent hydraulic conductivity approach. The equivalent hydraulic conductivity is used to account for head losses due to friction within the wellbore of the pumping well. Applying the MIPT method on the model simulated piezometric heads resulted in a specific discharge that underestimates the true specific discharge in the experimental aquifer by 18.8%, compared with the 57% underestimation of mass flux by the experiment reported by Goltz et al. (2009). Alternative simulation shows that the numerical model is capable of approximately replicating the experiment results when the equivalent hydraulic conductivity is reduced by an order of magnitude, suggesting that the accuracy of the MIPT estimation could be improved by expanding the physical meaning of the equivalent hydraulic conductivity to account for other factors such as orifice losses in addition to frictional losses within the wellbore. Numerical experiments also show that when applying the MIPT method to estimate hydraulic parameters, use of depth-integrated piezometric head instead of the head near the pump intake can reduce the estimation error resulting from well losses, but not the error associated with the well not being fully screened.

  2. Evaluation of a significantly shorter version of the Farnsworth-Munsell 100-hue test in patients with three different optic neuropathies.

    PubMed

    Nichols, B E; Thompson, H S; Stone, E M

    1997-03-01

    We tested the hypothesis that a subset of the Farnsworth-Munsell 100-hue test (FM-100) would be a sensitive, specific, and practical means of monitoring color vision in patients with chronic optic nerve disorders. We retrospectively analyzed the records of 1,113 patients affected with optic neuritis (ON), Graves' ophthalmopathy with suspected optic neuropathy, or idiopathic intracranial hypertension with suspected optic neuropathy (IIH). One hundred six records of patients showed that an FM-100 had been performed (23 ON, 46 Graves', 37 IIH). Forty additional patients were studied prospectively (11 ON, 17 Graves', 12 IIH). The sensitivity and specificity of all possible 21 chip subtests were compared against the same statistics for the entire test. We found that for these three optic nerve disorders, a test consisting of chips 22-42 had nearly the same sensitivity and specificity as the entire test when compared with the clinical diagnosis. At 90% specificity, the ratio of sensitivities of the short version to the original version of the test were IIH, 53%/45%; optic neuritis, 85%/79%; and Graves', 67%/70%. The majority of the clinical value of the test can be achieved in one fourth of the original examination time.

  3. A significantly lower potency observed for the 3rd WHO International Standard for Parvovirus B19V DNA with the cobas TaqScreen DPX test.

    PubMed

    Pisani, G; Cristiano, K; Fabi, S; Simeoni, M; Marino, F; Gaggioli, A

    2016-08-01

    In the context of the Official Medicines Control Laboratories plasma pool testing for Parvovirus B19 DNA, we use the cobas TaqScreen DPX test. When we re-evaluated this method using the 3rd B19 DNA WHO IS at the final concentration of 4 log IU/mL, we observed a titre lower than expected, i.e. 3.79 log IU/mL. Therefore, we further investigated the accuracy of the DPX test. The following B19V DNA materials were tested by using both the DPX test and an in-house real-time PCR: The 1st, 2nd and 3rd WHO ISs for B19V DNA The Non WHO B19V DNA Reference Material for NAT The Biological Reference Preparation B19 virus DNA for NAT testing, batch 1 . The DPX test showed a good accuracy for all B19V DNA materials with the exception of the 3rd WHO IS for B19V DNA. In fact, an underestimation of about 38% was observed for all dilutions of this standard with respect to the nominal titre. With the B19V in-house real-time PCR, all four materials proved to be well calibrated against the 1(st) WHO IS for B19V DNA, used as external standard curve. In this study, we demonstrated that the DPX test underestimates the B19V DNA content of the 3rd WHO IS for B19V DNA and that this is not due to an incorrect potency assigned to the standard but, most probably, to a mismatch between the primers/probe and the sequence of the target region in the 3rd WHO IS for B19V DNA. © 2016 International Society of Blood Transfusion.

  4. Exploring Differential Effects across Two Decoding Treatments on Item-Level Transfer in Children with Significant Word Reading Difficulties: A New Approach for Testing Intervention Elements

    ERIC Educational Resources Information Center

    Steacy, Laura M.; Elleman, Amy M.; Lovett, Maureen W.; Compton, Donald L.

    2016-01-01

    In English, gains in decoding skill do not map directly onto increases in word reading. However, beyond the Self-Teaching Hypothesis, little is known about the transfer of decoding skills to word reading. In this study, we offer a new approach to testing specific decoding elements on transfer to word reading. To illustrate, we modeled word-reading…

  5. Exploring Differential Effects across Two Decoding Treatments on Item-Level Transfer in Children with Significant Word Reading Difficulties: A New Approach for Testing Intervention Elements

    ERIC Educational Resources Information Center

    Steacy, Laura M.; Elleman, Amy M.; Lovett, Maureen W.; Compton, Donald L.

    2016-01-01

    In English, gains in decoding skill do not map directly onto increases in word reading. However, beyond the Self-Teaching Hypothesis, little is known about the transfer of decoding skills to word reading. In this study, we offer a new approach to testing specific decoding elements on transfer to word reading. To illustrate, we modeled word-reading…

  6. Performance of a Cartridge-Based Assay for Detection of Clinically Significant Human Papillomavirus (HPV) Infection: Lessons from VALGENT (Validation of HPV Genotyping Tests)

    PubMed Central

    Geraets, Daan; Cuzick, Jack; Cadman, Louise; Moore, Catherine; Vanden Broeck, Davy; Padalko, Elisaveta; Quint, Wim; Arbyn, Marc

    2016-01-01

    The Validation of Human Papillomavirus (HPV) Genotyping Tests (VALGENT) studies offer an opportunity to clinically validate HPV assays for use in primary screening for cervical cancer and also provide a framework for the comparison of analytical and type-specific performance. Through VALGENT, we assessed the performance of the cartridge-based Xpert HPV assay (Xpert HPV), which detects 14 high-risk (HR) types and resolves HPV16 and HPV18/45. Samples from women attending the United Kingdom cervical screening program enriched with cytologically abnormal samples were collated. All had been previously tested by a clinically validated standard comparator test (SCT), the GP5+/6+ enzyme immunoassay (EIA). The clinical sensitivity and specificity of the Xpert HPV for the detection of cervical intraepithelial neoplasia grade 2 or higher (CIN2+) and CIN3+ relative to those of the SCT were assessed as were the inter- and intralaboratory reproducibilities according to international criteria for test validation. Type concordance for HPV16 and HPV18/45 between the Xpert HPV and the SCT was also analyzed. The Xpert HPV detected 94% of CIN2+ and 98% of CIN3+ lesions among all screened women and 90% of CIN2+ and 96% of CIN3+ lesions in women 30 years and older. The specificity for CIN1 or less (≤CIN1) was 83% (95% confidence interval [CI], 80 to 85%) in all women and 88% (95% CI, 86 to 91%) in women 30 years and older. Inter- and intralaboratory agreements for the Xpert HPV were 98% and 97%, respectively. The kappa agreements for HPV16 and HPV18/45 between the clinically validated reference test (GP5+/6+ LMNX) and the Xpert HPV were 0.92 and 0.91, respectively. The clinical performance and reproducibility of the Xpert HPV are comparable to those of well-established HPV assays and fulfill the criteria for use in primary cervical cancer screening. PMID:27385707

  7. Performance on the Luria-Nebraska Neuropsychological Test Battery-Children's Revision: A Comparison of Children with and without Significant WISC-R VIQ-PIQ Discrepancies.

    ERIC Educational Resources Information Center

    Gilger, J. W.; Geary, D. C.

    1985-01-01

    Compared the performance of 56 children on the 11 subscales of the Luria-Nebraska Neuropsychological Battery-Children's Revision. Results revealed significant differences on Receptive Speech and Expressive Language subscales, suggesting a possible differential sensitivity of the children's Luria-Nebraska to verbal and nonverbal cognitive deficits.…

  8. Detection of anti-U3-RNP/fibrillarin IgG antibodies by line immunoblot assay has comparable clinical significance to immunoprecipitation testing in systemic sclerosis.

    PubMed

    Peterson, Lisa K; Jaskowski, Troy D; Mayes, Maureen D; Tebo, Anne E

    2016-04-01

    The aim of this study was to evaluate the performance and clinical relevance of a commercially available line immunoblot assay (LIA) for detecting anti-U3-RNP/fibrillarin (anti-U3-RNP), against immunoprecipitation (gold standard). This study involved a multi-ethnic cohort of 1000 American systemic sclerosis (SSc) patients and 50 healthy controls. Antinuclear antibodies and centromere antibodies were detected by indirect immunofluorescent antibody test, anti-topo I by immunodiffusion and anti-RNAP III by ELISA. The presence of anti-U3-RNP in select serum samples was detected by immunoprecipitation (IP) and LIA. By IP, U3-RNP antibody was detected in 75 (7.5 %) patients with SSc. Overall agreement between LIA and IP was very good (κ = 0.966). Analytic sensitivity and specificity of the U3-RNP LIA was 100 and 94.7 %, respectively. Clinical features associated with positivity for the anti-U3-RNP antibody include diffuse cutaneous SSc and increased prevalence of renal crisis, consistent with previous studies that used IP. Testing for U3-RNP antibodies is only performed by a small number of laboratories due to the complexity of both performance and interpretation of the IP. LIA is faster and less complex than IP. Excellent agreement between IP and LIA demonstrates that LIA is an acceptable and attractive alternative to IP for anti-U3-RNP detection.

  9. [Clinical significance of fractional exhaled nitric oxide combined with in vitro allergen test in identifying children at a high risk of asthma among those with recurrent wheezing].

    PubMed

    Hou, Wei-Peng; Wang, Ya-Jie; Qiao, Li-Hong; Shen, Hui-Li

    2017-09-01

    To investigate the clinical value of combined determination of in vitro allergens and fractional exhaled nitric oxide (FeNO) in indentifying children at a high risk of asthma among those with recurrent wheezing. A total of 148 children with recurrent wheezing (0.5-6 years old) were enrolled as study subjects, and 80 healthy children who underwent physical examination were enrolled as the control group. Pharmacia UniCAP immunoassay analyzer was used to measure specific immunoglobulin E (sIgE). Nano Coulomb Nitric Oxide Analyzer was used to measure FeNO. The asthma predictive index (API) was evaluated. The recurrent wheezing group had a significantly higher proportion of children with positive sIgE than the control group [68.9% (102/148) vs 11.3% (9/80); P<0.05]. The recurrent wheezing group also had significantly higher levels and positive rate of FeNO than the control group (P<0.05). The overall positive rate of API in children with wheezing was 32.4%, and the API-positive children had a significantly higher FeNO value than the API-negative children (51±6 ppb vs 13±5 ppb; P<0.05). The detection rate of API was 40.2% (41/102) in positive-sIgE children and 50.1% (38/73) in FeNO-positive children, and there was no significant difference between these two groups. The children with positive sIgE and FeNO had a significantly higher detection rate of API (81.4%) than those with positive sIgE or FeNO (P<0.05). Combined determination of FeNO and in vitro allergens is more sensitive in detecting children at a high risk of asthma than FeNO or in vitro allergens determination alone and provides a good method for early identification, diagnosis, and intervention of asthma in children.

  10. Effect of GLP-1 and GIP on C-peptide secretion after glucagon or mixed meal tests: Significance in assessing B-cell function in diabetes.

    PubMed

    Guglielmi, C; Del Toro, R; Lauria, A; Maurizi, A R; Fallucca, S; Cappelli, A; Angeletti, S; Lachin, J M; Pozzilli, P

    2017-09-01

    The aim of the study was to investigate the different B-cell responses after a glucagon stimulation test (GST) versus mixed meal tolerance test (MMTT). We conducted GST and MMTT in 10 healthy people (aged 25-40 years) and measured C-peptide, gastric inhibitory peptide (GIP) and glucagon-like peptide-1 (GLP-1) at different time points after the administration of 1 mg i.v. glucagon for GST or a liquid mixed meal for MMTT. The GST stimulated C-peptide showed a mean increase of 147.1%, whereas the mean increase of MMTT stimulated C-peptide was 99.82% (Δincrease = 47.2%). Maximum C-peptide level reached with the MMTT was greater than that obtained with the GST (C-pept max MMTT = 2.35 nmol/L vs C-pep max GST = 1.9 nmol/L). A positive and linear correlation was found between the GST incremental area under the curve C-peptide and the MMTT incremental area under the curve C-peptide (r = 0.618, P = .05). After GST, there was no increment of GIP and glucagon like peptide-1 levels compared to baseline levels. A positive and linear correlation between GIP and C-peptide levels was observed only for the MMTT (r = 0.922, P = .008) indicating that in the GST, the C-peptide response is independent of the incretin axis response. Although the 2 stimulation tests may elicit a similar response in C-peptide secretion, B-cell response to MMTT depends on a functionally normal incretin axis. These results may have implications when investigating the B-cell response in people with diabetes and for studies in which stimulated C-peptide secretion is used as primary or secondary outcome for response to therapy. Copyright © 2017 John Wiley & Sons, Ltd.

  11. Results of in-situ biofouling control, and corrosion test at Punta Tuna, Puerto Rico and its significance on OTEC heater exchanger design

    SciTech Connect

    Sasscer, D.S.; Morgan, T.O.; Tosteson, T.R.

    1983-06-01

    Because Ocean Thermal Energy Conversion (OTEC) operates at a low thermodynamic efficiency, heat exchangers represent a major portion of the overall cost of an OTEC power plant. For this reason, the commercial viability of OTEC depends on the design of efficient and inexpensive heat exchangers which have an operational life expectancy of 20 to 30 years and which can be maintained at a high level of efficiency by the use of effective biofouling control. Summarized here are the results of experiments conducted by the Center for Energy and Environment Research of the University of Puerto Rico to: determine the nature of the biofilm which develops on heat exchanger surfaces exposed to running seawater, test the effectiveness of brush cleaning and chlorination in controlling biofouling on these surfaces and study the corrosion behavior of zinc protected aluminum alloys under OTEC conditions in an attempt to qualify them for use in low cost OTEC heat exchangers.

  12. Interim Guidance on the Treatment of Condensable Particulate Matter Test Results in the Prevention of Significant Deterioration and Nonattainment New Source Review Permitting Programs

    EPA Pesticide Factsheets

    This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

  13. [The significance of the results of crash-tests with the use of the models of the pedestrians' lower extremities for the prevention of the traffic road accidents].

    PubMed

    Smirenin, S A; Fetisov, V A; Grigoryan, V G; Gusarov, A A; Kucheryavets, Yu O

    The disabling injuries inflicted during road traffic accidents (RTA) create a serious challenge for the public health services and are at the same time a major socio-economic problem in the majority of the countries throughout the world. The injuries to the lower extremities of the pedestrians make up the largest fraction of the total number of the non-lethal RTA injuries. Most of them are responsible for the considerable deterioration of the quality of life for the participants in the accidents during the subsequent period. The objective of the present study was to summarize the currently available results of experimental testing of the biomechanical models of the pedestrians' lower extremities in the framework of the program for the prevention of the road traffic accidents as proposed by the World Health Organization (WHO, 2004). The European Enhanced Safety Vehicle Committee (EEVC) has developed a series of crash-tests with the use of the models of the pedestrians' lower extremities simulating the vehicle bumper-pedestrian impact. The models are intended for the assessment of the risk of the tibia fractures and the injuries to the knee joint ligaments. The experts of EEVC proposed the biomechanical criteria for the acceleration of the knee and talocrural parts of the lower limbs as well as for the shear displacement of the knee and knee-bending angle. The engineering solution of this problem is based on numerous innovation proposals being implemented in the machine-building industry with the purpose of reducing the stiffness of structural elements of the bumper and other front components of a modern vehicle designed to protect the pedestrians from severe injuries that can be inflicted in the road traffic accidents. The activities of the public health authorities (in the first place, bureaus of forensic medical expertise and analogous facilities) have a direct bearing on the solution of the problem of control of road traffic injuries because they are possessed of

  14. A significant component of ageing (DNA damage) is reflected in fading breeding colors: an experimental test using innate antioxidant mimetics in painted dragon lizards.

    PubMed

    Olsson, Mats; Tobler, Michael; Healey, Mo; Perrin, Cecile; Wilson, Mark

    2012-08-01

    A decade ahead of their time, von Schantz et al. united sexual selection and free radical biology by identifying causal links between deep-rooted physiological processes that dictate resistance to toxic waste from oxidative metabolism (reactive oxygen species, ROS), and phenotypic traits, such as ornaments. Ten years later, these ideas have still only been tested with indirect estimates of free radical levels (oxidative stress) subsequent to the action of innate and dietary antioxidants. Here, we measure net superoxide (a selection pressure for antioxidant production) and experimentally manipulate superoxide antioxidation using a synthetic mimetic of superoxide dismutase (SOD), Eukarion 134 (EUK). We then measure the toxic effect of superoxide in terms of DNA erosion and concomitant loss of male breeding coloration in the lizard, Ctenophorus pictus. Control males suffered more DNA damage than EUK males. Spectroradiometry showed that male coloration is lost in relation to superoxide and covaries with DNA erosion; in control males, these variables explained loss of color, whereas in EUK males, the fading of coloration was unaffected by superoxide and unrelated to DNA damage. Thus, EUK's powerful antioxidation removes the erosion effect of superoxide on coloration and experimentally verifies the prediction that colors reflect innate capacity for antioxidation. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  15. Validation of the MicroScan-96 for the species identification and methicillin susceptibility testing of clinical significant coagulase-negative staphylococci.

    PubMed

    Patteet, L; Goossens, H; Ieven, M

    2012-05-01

    An automated system, MicroScan WalkAway-96, in conjugation with Combo Pos® 28 panels, was validated for the identification and methicillin susceptibility of coagulase-negative staphylococci (CNS). The performance of this system was evaluated on 428 CNS. Identification results were compared using a validated in-house method. Methicillin susceptibility was compared with oxacillin MIC testing and the presence of the mecA gene by PCR (in-house real-time method). The MicroScan system correctly identified 94.6% of the staphylococci (405 out of 428). 3.5% of the strains (15 out of 428) were not correctly identified. 1.9% of the isolates (8 out of 428) were correctly identified with a low probability. Identification of Staphylococcus warneri and Staphylococcus lugdunensis was determined with the least accuracy. Microscan combines both oxacillin and cefoxitin for determination of the methicillin susceptibility result. Correlation between this result and the mecA method was 97.6%. Correlation with the oxacillin MIC method was also 97.6%. Fourteen isolates showed a discrepant result, 8 were reported to be resistant in mecA-negative strains, 2 were reported false-susceptible in mecA positive strains and 4 strains showed a discrepant result with oxacillin MIC, but not with mecA determination. The automated system can be considered a simple and reliable method for identification and methicillin susceptibility of CNS.

  16. Exploring Differential Effects Across Two Decoding Treatments on Item-Level Transfer in Children with Significant Word Reading Difficulties: A New Approach for Testing Intervention Elements

    PubMed Central

    Steacy, Laura M.; Elleman, Amy M.; Lovett, Maureen W.; Compton, Donald L.

    2016-01-01

    In English, gains in decoding skill do not map directly onto increases in word reading. However, beyond the Self-Teaching Hypothesis (Share, 1995), little is known about the transfer of decoding skills to word reading. In this study, we offer a new approach to testing specific decoding elements on transfer to word reading. To illustrate, we modeled word-reading gains among children with reading disability (RD) enrolled in Phonological and Strategy Training (PHAST) or Phonics for Reading (PFR). Conditions differed in sublexical training with PHAST stressing multi-level connections and PFR emphasizing simple grapheme-phoneme correspondences. Thirty-seven children with RD, 3rd – 6th grade, were randomly assigned 60 lessons of PHAST or PFR. Crossed random-effects models allowed us to identify specific intervention elements that differentially impacted word-reading performance at posttest, with children in PHAST better able to read words with variant vowel pronunciations. Results suggest that sublexical emphasis influences transfer gains to word reading. PMID:28596701

  17. Targeted Resequencing and Systematic In Vivo Functional Testing Identifies Rare Variants in MEIS1 as Significant Contributors to Restless Legs Syndrome

    PubMed Central

    Schulte, Eva C.; Kousi, Maria; Tan, Perciliz L.; Tilch, Erik; Knauf, Franziska; Lichtner, Peter; Trenkwalder, Claudia; Högl, Birgit; Frauscher, Birgit; Berger, Klaus; Fietze, Ingo; Hornyak, Magdolna; Oertel, Wolfgang H.; Bachmann, Cornelius G.; Zimprich, Alexander; Peters, Annette; Gieger, Christian; Meitinger, Thomas; Müller-Myhsok, Bertram; Katsanis, Nicholas; Winkelmann, Juliane

    2014-01-01

    Restless legs syndrome (RLS) is a common neurologic condition characterized by nocturnal dysesthesias and an urge to move, affecting the legs. RLS is a complex trait, for which genome-wide association studies (GWASs) have identified common susceptibility alleles of modest (OR 1.2–1.7) risk at six genomic loci. Among these, variants in MEIS1 have emerged as the largest risk factors for RLS, suggesting that perturbations in this transcription factor might be causally related to RLS susceptibility. To establish this causality, direction of effect, and total genetic burden of MEIS1, we interrogated 188 case subjects and 182 control subjects for rare alleles not captured by previous GWASs, followed by genotyping of ∼3,000 case subjects and 3,000 control subjects, and concluded with systematic functionalization of all discovered variants using a previously established in vivo model of neurogenesis. We observed a significant excess of rare MEIS1 variants in individuals with RLS. Subsequent assessment of all nonsynonymous variants by in vivo complementation revealed an excess of loss-of-function alleles in individuals with RLS. Strikingly, these alleles compromised the function of the canonical MEIS1 splice isoform but were irrelevant to an isoform known to utilize an alternative 3′ sequence. Our data link MEIS1 loss of function to the etiopathology of RLS, highlight how combined sequencing and systematic functional annotation of rare variation at GWAS loci can detect risk burden, and offer a plausible explanation for the specificity of phenotypic expressivity of loss-of-function alleles at a locus broadly necessary for neurogenesis and neurodevelopment. PMID:24995868

  18. The scratch test for identifying the lower liver edge is at least as accurate as percussion and is significantly more effective for young trainees-a randomised comparative trial.

    PubMed

    Huelsen, Alexander; Fischer, Jesse; Hegarty, Justin; Ashcroft, Anna; Frampton, Christopher Ma; Barclay, Murray L

    2016-12-02

    Clinical examination of the liver requires experience to achieve accuracy. The scratch test is a simple technique to identify the lower liver edge and enhance liver palpation, and may be easier for trainees. We aimed to evaluate the accuracy of the scratch test compared to percussion at different levels of medical training. Eight examiners, from trainee intern to consultant level, were randomised to scratch or percussion testing, followed by liver palpation, on 50 subjects. Later, each examiner performed the alternative test on each subject. Confidence with each test was rated 0-3 (unsuccessful-very confident). Ultrasound scan (US) was performed as a reference for liver location. Ultrasound revealed 33/50 (66%) of livers extended below the right costal margin in the midclavicular line during quiet respiration (range 0.5-16cm). Of these, 33, 87% and 76% were identified within 2cm of the US location using scratch and percussion tests, respectively (p>0.05) for all examiners, but with significantly greater accuracy for the scratch test in young trainees (91% v 75%; p=0.016). Ability to palpate the liver was not different following either test. The training effect was assessed by comparing the accuracy results of the first 25 with the last 25 examined subjects, revealing a significant increase in accuracy with percussion from 71% to 85% (p=0.038) compared to no change with the scratch test (88% and 86%). Examiner confidence in the test result was significantly higher using the scratch test versus percussion, average confidence scores being 2.2 versus 1.8 (p<0.001), with a greater difference in the young trainee group at 2.4 versus 1.7 (p<0.001). The scratch test was at least as accurate as percussion overall in identifying the lower liver edge and significantly more accurate for the young trainees. The scratch test requires less training and in addition, all examiners and especially the young trainees were significantly more confident in their findings using the

  19. Lack of Statistical Significance

    ERIC Educational Resources Information Center

    Kehle, Thomas J.; Bray, Melissa A.; Chafouleas, Sandra M.; Kawano, Takuji

    2007-01-01

    Criticism has been leveled against the use of statistical significance testing (SST) in many disciplines. However, the field of school psychology has been largely devoid of critiques of SST. Inspection of the primary journals in school psychology indicated numerous examples of SST with nonrandom samples and/or samples of convenience. In this…

  20. Power Differences among Tests of Combined Significance.

    ERIC Educational Resources Information Center

    Becker, Betsy Jane

    Power is an indicator of the ability of a statistical analysis to detect a phenomenon that does in fact exist. The issue of power is crucial for social science research because sample size, effects, and relationships studied tend to be small and the power of a study relates directly to the size of the effect of interest and the sample size.…

  1. Significant issues and changes for ANSI/ASME OM-1 1981, part 1, ASME OMc code-1994, and ASME OM Code-1995, Appendix I, inservice testing of pressure relief devices in light water reactor power plants

    SciTech Connect

    Seniuk, P.J.

    1996-12-01

    This paper identifies significant changes to the ANSI/ASME OM-1 1981, Part 1, and ASME Omc Code-1994 and ASME OM Code-1995, Appendix I, {open_quotes}Inservice Testing of Pressure Relief Devices in Light-Water Reactor Power Plants{close_quotes}. The paper describes changes to different Code editions and presents insights into the direction of the code committee and selected topics to be considered by the ASME O&M Working Group on pressure relief devices. These topics include scope issues, thermal relief valve issues, as-found and as-left set-pressure determinations, exclusions from testing, and cold setpoint bench testing. The purpose of this paper is to describe some significant issues being addressed by the O&M Working Group on Pressure Relief Devices (OM-1). The writer is currently the chair of OM-1 and the statements expressed herein represents his personal opinion.

  2. The significance of repeat testing in Turkish blood donors screened with HBV, HCV and HIV immunoassays and the importance of S/CO ratios in the interpretation of HCV/HIV screening test results and as a determinant for further confirmatory testing.

    PubMed

    Acar, Ali; Kemahli, Sabri; Altunay, Husnu; Kosan, Erdogan; Oncul, Oral; Gorenek, Levent; Cavuslu, Saban

    2010-06-01

    The purpose of this study was to investigate the intra-assay correlations amongst initial reactive and repeat screening results used in enzyme immunoassays (EIAs) for hepatitis B virus (HBV), hepatitis C virus (HCV) and HIV in blood donors. This study evaluated the value of using the power of the signal to cut-off (S/CO) ratio index for confirming anti-HCV/HIV reactive screening results, thereby touching upon the utility of S/CO indices in determining whether further confirmatory testing was necessary. Screening test results of the 72,695 blood donors were evaluated over a 1-year period. Correlation analysis among each initial test and retests was done by Pearson r test. Appropriate S/CO values to determine the need of the confirmation testing was investigated by ROC analyses. EIA intra-assay correlations were of statistical significance and were determined as follows: 0.948 for anti-HCV, 0.827 for anti-HIV and 0.948 for HBsAg. The threshold S/CO ratio values which predicted more than 95% of the confirmation test result were 3.8 for HCV and 5.6 for HIV. We were able to demonstrate a strong level of intra-assay correlation amongst EIAs, thereby eliminating the need for repetition of the screening test. Hence, we suggest that repeat screening should only be limited to HBV and HIV tests with low EIA S/CO ratios. Thus, using the power of the S/CO ratio in determining the need for HCV confirmation testing can be a cost-effective measure, especially if the S/CO value is >or=3.8.

  3. Assessing the Significance of Cohort and Period Effects in Hierarchical Age-Period-Cohort Models: Applications to Verbal Test Scores and Voter Turnout in U.S. Presidential Elections

    PubMed Central

    Frenk, Steven M.; Yang, Yang Claire; Land, Kenneth C.

    2014-01-01

    In recently developed hierarchical age-period-cohort (HAPC) models, inferential questions arise: How can one assess or judge the significance of estimates of individual cohort and period effects in such models? And how does one assess the overall statistical significance of the cohort and/or the period effects? Beyond statistical significance is the question of substantive significance. This paper addresses these questions. In the context of empirical applications of linear and generalized linear mixed-model specifications of HAPC models using data on verbal test scores and voter turnout in U.S. presidential elections, respectively, we describe a two-step approach and a set of guidelines for assessing statistical significance. The guidelines include assessments of patterns of effects and statistical tests both for the effects of individual cohorts and time periods as well as for entire sets of cohorts and periods. The empirical applications show strong evidence that trends in verbal test scores are primarily cohort driven, while voter turnout is primarily a period phenomenon. PMID:25392566

  4. Assessing the Significance of Cohort and Period Effects in Hierarchical Age-Period-Cohort Models: Applications to Verbal Test Scores and Voter Turnout in U.S. Presidential Elections.

    PubMed

    Frenk, Steven M; Yang, Yang Claire; Land, Kenneth C

    2013-01-01

    In recently developed hierarchical age-period-cohort (HAPC) models, inferential questions arise: How can one assess or judge the significance of estimates of individual cohort and period effects in such models? And how does one assess the overall statistical significance of the cohort and/or the period effects? Beyond statistical significance is the question of substantive significance. This paper addresses these questions. In the context of empirical applications of linear and generalized linear mixed-model specifications of HAPC models using data on verbal test scores and voter turnout in U.S. presidential elections, respectively, we describe a two-step approach and a set of guidelines for assessing statistical significance. The guidelines include assessments of patterns of effects and statistical tests both for the effects of individual cohorts and time periods as well as for entire sets of cohorts and periods. The empirical applications show strong evidence that trends in verbal test scores are primarily cohort driven, while voter turnout is primarily a period phenomenon.

  5. The highly selective 5-hydroxytryptamine (5-HT)2A receptor antagonist, EMD 281014, significantly increases swimming and decreases immobility in male congenital learned helpless rats in the forced swim test.

    PubMed

    Patel, Jignesh G; Bartoszyk, Gerd D; Edwards, Emmeline; Ashby, Charles R

    2004-04-01

    We examined the effect of the highly selective 5-hydroxytryptamine (5-HT)(2A) receptor antagonist 7-[4-[2-(4-fluoro-phenyl)-ethyl]-piperazine-1-carbonyl]-1H-indole-3-carbonitrile HCl (EMD 281014) in congenital learned helpless male rats in the forced swim test. The administration of EMD-281014 (0.3-30 mg/kg i.p.) to congenital learned helpless rats dose-dependently and significantly (at 10 and 30 mg/kg) decreased immobility and increased swimming compared to vehicle-treated animals. Thus, EMD 281014 produces effects in the forced swim test resembling those of antidepressants.

  6. Prospective evaluation of the Hybrid Capture 2 and AMPLICOR human papillomavirus (HPV) tests for detection of 13 high-risk HPV genotypes in atypical squamous cells of uncertain significance.

    PubMed

    Halfon, Philippe; Trepo, Elisabeth; Antoniotti, Gilles; Bernot, Catherine; Cart-Lamy, Philippe; Khiri, Hacène; Thibaud, Didier; Marron, Jean; Martineau, Agnès; Pénaranda, Guillaume; Benmoura, Dominique; Blanc, Bernard

    2007-02-01

    The use of high-risk human papillomavirus (hrHPV) testing as an adjunct to cervical cytology in population-based screening programs is currently based on DNA hybridization and PCR assays. The aim of this study was to prospectively assess the diagnostic performance of the Hybrid Capture 2 test (HC2; Digene Corporation) in comparison with that of the recently developed PCR-based AMPLICOR HPV test (Roche Molecular Systems) for the detection of 13 hrHPV types. A reverse line blot hybridization assay (Innogenetics) was used as an internal reference standard in discordant cases. Two hundred seventy-one patients with atypical squamous cells of uncertain significance (ASCUS) in cervical samples underwent hrHPV testing. The chi-square test was performed to compare respective proportions. Totals of 160/271 (59%) and 156/271 (58%) were found to be positive for hrHPV with HC2 and AMPLICOR, respectively. Concordant results were obtained for 235 (86.7%) of the 271 samples (kappa statistic, 0.73 +/- 0.04). Considering types 26, 53, and 66 as oncogenic types, negative predictive values (NPVs) of HC2 and AMPLICOR were 92.8% and 87.8%, respectively (difference was not significant), and their respective accuracies were 94.8% and 91.9% (difference was not significant). Considering types 26, 53, and 66 as not oncogenic, the respective HC2 and AMPLICOR NPVs were 92.8% and 97.4% (difference was not significant), and accuracy was significantly higher for the AMPLICOR assay (95.9% versus 90.8% for HC2) (P<0.05). For ASCUS samples, the NPV was 92.8% for HC2 testing and might be compromised if the copy number of HPV DNA was low. The NPV was 97.4% for the AMPLICOR assay and might be compromised if HPV types 26, 53, and 66 were considered oncogenic. The accuracy of these two assays is good and is compatible with routine clinical use in the triage of ASCUS cases.

  7. Effects of dependence in high-dimensional multiple testing problems

    PubMed Central

    Kim, Kyung In; van de Wiel, Mark A

    2008-01-01

    Background We consider effects of dependence among variables of high-dimensional data in multiple hypothesis testing problems, in particular the False Discovery Rate (FDR) control procedures. Recent simulation studies consider only simple correlation structures among variables, which is hardly inspired by real data features. Our aim is to systematically study effects of several network features like sparsity and correlation strength by imposing dependence structures among variables using random correlation matrices. Results We study the robustness against dependence of several FDR procedures that are popular in microarray studies, such as Benjamin-Hochberg FDR, Storey's q-value, SAM and resampling based FDR procedures. False Non-discovery Rates and estimates of the number of null hypotheses are computed from those methods and compared. Our simulation study shows that methods such as SAM and the q-value do not adequately control the FDR to the level claimed under dependence conditions. On the other hand, the adaptive Benjamini-Hochberg procedure seems to be most robust while remaining conservative. Finally, the estimates of the number of true null hypotheses under various dependence conditions are variable. Conclusion We discuss a new method for efficient guided simulation of dependent data, which satisfy imposed network constraints as conditional independence structures. Our simulation set-up allows for a structural study of the effect of dependencies on multiple testing criterions and is useful for testing a potentially new method on π0 or FDR estimation in a dependency context. PMID:18298808

  8. Declinol, a Complex Containing Kudzu, Bitter Herbs (Gentian, Tangerine Peel) and Bupleurum, Significantly Reduced Alcohol Use Disorders Identification Test (AUDIT) Scores in Moderate to Heavy Drinkers: A Pilot Study

    PubMed Central

    Kushner, Steven; Han, David; Oscar-Berman, Marlene; William Downs, B; Madigan, Margaret A; Giordano, John; Beley, Thomas; Jones, Scott; Barh, Debmayla; Simpatico, Thomas; Dushaj, Kristina; Lohmann, Raquel; Braverman, Eric R; Schoenthaler, Stephen; Ellison, David; Blum, Kenneth

    2013-01-01

    It is well established that inherited human aldehyde dehydrogenase 2 (ALDH-2) deficiency reduces the risk for alcoholism. Kudzu plants and extracts have been used for 1,000 years in traditional Chinese medicine to treat alcoholism. Kudzu contains daidzin, which inhibits ALDH-2 and suppresses heavy drinking in rodents. Decreased drinking due to ALDH-2 inhibition is attributed to aversive properties of acetaldehyde accumulated during alcohol consumption. However not all of the anti-alcohol properties of diadzin are due to inhibition of ALDH-2. This is in agreement with our earlier work showing significant interaction effects of both pyrozole (ALDH-2 inhibitor) and methyl-pyrozole (non-inhibitor) and ethanol’s depressant effects. Moreover, it has been suggested that selective ALDH 2 inhibitors reduce craving for alcohol by increasing dopamine in the nucleus accumbens (NAc). In addition there is significant evidence related to the role of the genetics of bitter receptors (TAS2R) and its stimulation as an aversive mechanism against alcohol intake. The inclusion of bitters such as Gentian & Tangerine Peel in Declinol provides stimulation of gut TAS2R receptors which is potentially synergistic with the effects of Kudzu. Finally the addition of Radix Bupleuri in the Declinol formula may have some protective benefits not only in terms of ethanol induced liver toxicity but neurochemical actions involving endorphins, dopamine and epinephrine. With this information as a rationale, we report herein that this combination significantly reduced Alcohol Use Disorders Identification Test (AUDIT) scores administered to ten heavy drinkers (M=8, F=2; 43.2 ± 14.6 years) attending a recovery program. Specifically, from the pre-post comparison of the AUD scores, it was found that the score of every participant decreased after the intervention which ranged from 1 to 31. The decrease in the scores was found to be statistically significant with the p-value of 0.00298 (two-sided paired

  9. The clinical application of HPV E6/E7 mRNA testing in triaging women with atypical squamous cells of undetermined significance or low-grade squamous intra-epithelial lesion Pap smear: A meta-analysis.

    PubMed

    Yang, Li; Zhu, Yuanhang; Bai, Yang; Zhang, Xiaoan; Ren, Chenchen

    2017-01-01

    The aim is to evaluate the clinical application value and correlation with cervical lesions' progression of human papillomavirus (HPV) E6/E7 mRNA test in women with atypical squamous cells of undetermined significance (ASCUS/borderline) or low-grade squamous intraepithelial lesions (LSILs/mild dyskaryosis) cytological abnormalities. A meta-analysis was conduct by searching China National Knowledge Infrastructure (1979-2016), Wanfang Date (1998-2016), VIP (1989-2016), PubMed (1950-2016), Web of Science (1950-2016) and Elsevier Science Direct (1998-2016), for studies on effect of HPV E6/E7 mRNA detection in women with ASCUS/LSIL/dyskaryosis. Study selection and appraisal were conducted independently by three authors, according to inclusive and exclusive criteria. Then, a meta-analysis was performed using the RevMan4.2 software. The subgroups analysis was conducted according to women's initial HPV DNA test results. Six articles with a total of 1024 subjects were included in the study. It was concluded that a positive HPV E6/E7 mRNA tested result have a higher risk of progressing to CIN2+ in future 2 years than a negative result. The pooled relative risk (RR) is 3.08, (95% confidence interval [CI] = 1.57-6.07, P < 0.05). The same situation was also observed in the subgroup of HPV DNA tested positive group and HPV DNA tested unlimited group. The pooled RR value of the two subgroups was, respectively, 1.98, (95% CI = 1.19-1.19, P < 0.05) and 7.58, (95% CI = 3.64-3.64, P < 0.05). A positive HPV E6/E7 mRNA testing result suggested the women with ASCUS, or LSIL Pap smear was in a truly dangerous position, which is an adverse prognostic factor. It suggested that cervical lesions stay in a progressing status and these women should be referred for colposcopy and strengthen follow-up promptly. Whereas, women with a negative HPV E6/E7 mRNA testing result can increase follow-up interval, by comprehensively considering their situation, thus, avoiding unnecessary colposcopy and

  10. Indirect antiglobulin test-crossmatch using low-ionic-strength saline-albumin enhancement medium and reduced incubation time: effectiveness in the detection of most clinically significant antibodies and impact on blood utilization.

    PubMed

    Dinardo, C L; Bonifácio, S L; Mendrone, A

    2014-01-01

    Indirect antiglobulin test-crossmatch (IAT-XM) using enhancement media such as low-ionic-strength saline (LISS) and polyethylene glycol (PEG) usually requires 15 minutes of incubation. These methods are necessary when testing samples from blood recipients who have a higher risk of alloimmunization. In emergency situations, IAT-XM can be time-consuming and can influence presurgery routine, resulting in more red blood cell (RBC) units being tested and stored to avoid the transfusion of uncrossmatched ones. The objective of this study was to evaluate the performance of a LISS-albumin enhancer to intensify antigen-antibody reaction after 5 minutes of 37oC incubation and compare this performance with that of other enhancers, gel, and conventional tube testing. Second, the study evaluated the impact of this method's implementation in the C:T ratio (crossmatched to transfused RBC units) of a transfusion laboratory. Ninety serum samples containing alloantibodies of potential clinical significance were tested against phenotyped RBCs using four different methods: (1) tube with LISS-albumin enhancer (5 minutes of incubation), (2) tube with LISS-albumin and PEG (15 minutes of incubation), (3) gel, and (4) conventional tube method (60 minutes of incubation). In parallel, the study compared the C:T ratio of a tertiary-hospital transfusion laboratory in two different periods: 3 months before and 3 months after the implementation of the 5-minute IAT-XM protocol. The use of LISS-albumin with 5 minutes of incubation exhibited the same performance as LISS-albumin, PEG, and gel with 15 minutes of incubation. Conventional tube method results were equally comparable, but reactions were significantly less intense, except for anti-c (p = 0.406). Accuracy was 100 percent for all selected methods. After the implementation of the 5-minute IAT-XM protocol, the C:T ratio fell from 2.74 to 1.29 (p < 0.001). IAT-XM can have its incubation time reduced to 5 minutes with the use of LISS

  11. Spectral resampling based on user-defined inter-band correlation filter: C3 and C4 grass species classification

    NASA Astrophysics Data System (ADS)

    Adjorlolo, Clement; Mutanga, Onisimo; Cho, Moses A.; Ismail, Riyad

    2013-04-01

    In this paper, a user-defined inter-band correlation filter function was used to resample hyperspectral data and thereby mitigate the problem of multicollinearity in classification analysis. The proposed resampling technique convolves the spectral dependence information between a chosen band-centre and its shorter and longer wavelength neighbours. Weighting threshold of inter-band correlation (WTC, Pearson's r) was calculated, whereby r = 1 at the band-centre. Various WTC (r = 0.99, r = 0.95 and r = 0.90) were assessed, and bands with coefficients beyond a chosen threshold were assigned r = 0. The resultant data were used in the random forest analysis to classify in situ C3 and C4 grass canopy reflectance. The respective WTC datasets yielded improved classification accuracies (kappa = 0.82, 0.79 and 0.76) with less correlated wavebands when compared to resampled Hyperion bands (kappa = 0.76). Overall, the results obtained from this study suggested that resampling of hyperspectral data should account for the spectral dependence information to improve overall classification accuracy as well as reducing the problem of multicollinearity.

  12. Improving the performance of reflex Human Papilloma Virus (HPV) testing in triaging women with atypical squamous cells of undetermined significance (ASCUS): A restrospective study in a tertiary hospital in United Arab Emirates (UAE).

    PubMed

    Fakhreldin, Marwa; Elmasry, Karim

    2016-02-03

    Cervical cancer is the second commonest cancer in women worldwide. Infection with oncogenic types of human Papillomavirus (HPV) is the most important risk factor for developing cervical cancer. Reflex High risk HPV (HR-HPV) testing is of significant value in the assessment of Papanicolaou (Pap) smear results where ASCUS are identified. To improve the performance of reflex HR-HPV testing in triage of ASCUS and analyze the factors impacting it. In this study, we generated a database of 9641 women who had cervical smears collected during the study period from the cytopathology record in a large tertiary hospital in UAE. These included 297 smears with ASCUS diagnosis. All cases were retrospectively followed up with a mean duration of 2.44 years. We analyzed data according to the outcome based on several follow-up Pap smear analysis as the reference assessment. We detected HR-HPV infection in 17.9% of cases. 9.1% <25, 28.8% 25-34 and 62.1% ≥35 years old. HR-HPV prevalence was higher among premenopausal women (20.7%) compared to postmenopausal women (9.5%) (P-value=0.044). The rate of progression to high grade lesions was also higher (28.7%) in the premenopausal group compared to (12.8%) in the postmenopausal group. Reflex HPV testing had an overall sensitivity of 41.1%, specificity of 88.2%, positive predictive value (PPV) of 62.1%, and negative predictive value (NPV) of 75.9% in detection of cervical lesions. These figures were higher on combining premenopausal status and complaint of abnormal bleeding or discharge/itching (66.7%, 93.3%, 66.8% and 93.3% respectively). The sensitivity, specificity and NPV of reflex HPV testing in the triage of ASCUS cases can be more accurate in premenopausal women upon adding age group and presenting complaint as a triage item. This improves the performance of reflex HPV testing and the subsequent selection of high risk patients for colposcopy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. The VITRO Score (Von Willebrand Factor Antigen/Thrombocyte Ratio) as a New Marker for Clinically Significant Portal Hypertension in Comparison to Other Non-Invasive Parameters of Fibrosis Including ELF Test

    PubMed Central

    Hametner, Stephanie; Ferlitsch, Arnulf; Ferlitsch, Monika; Etschmaier, Alexandra; Schöfl, Rainer; Ziachehabi, Alexander; Maieron, Andreas

    2016-01-01

    Background Clinically significant portal hypertension (CSPH), defined as hepatic venous pressure gradient (HVPG) ≥10 mmHg, causes major complications. HVPG is not always available, so a non-invasive tool to diagnose CSPH would be useful. VWF-Ag can be used to diagnose. Using the VITRO score (the VWF-Ag/platelet ratio) instead of VWF-Ag itself improves the diagnostic accuracy of detecting cirrhosis/ fibrosis in HCV patients. Aim This study tested the diagnostic accuracy of VITRO score detecting CSPH compared to HVPG measurement. Methods All patients underwent HVPG testing and were categorised as CSPH or no CSPH. The following patient data were determined: CPS, D’Amico stage, VITRO score, APRI and transient elastography (TE). Results The analysis included 236 patients; 170 (72%) were male, and the median age was 57.9 (35.2–76.3; 95% CI). Disease aetiology included ALD (39.4%), HCV (23.4%), NASH (12.3%), other (8.1%) and unknown (11.9%). The CPS showed 140 patients (59.3%) with CPS A; 56 (23.7%) with CPS B; and 18 (7.6%) with CPS C. 136 patients (57.6%) had compensated and 100 (42.4%) had decompensated cirrhosis; 83.9% had HVPG ≥10 mmHg. The VWF-Ag and the VITRO score increased significantly with worsening HVPG categories (P<0.0001). ROC analysis was performed for the detection of CSPH and showed AUC values of 0.92 for TE, 0.86 for VITRO score, 0.79 for VWF-Ag, 0.68 for ELF and 0.62 for APRI. Conclusion The VITRO score is an easy way to diagnose CSPH independently of CPS in routine clinical work and may improve the management of patients with cirrhosis. PMID:26895398

  14. Metallographic autopsies of full-scale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN: II. Significant reduction of strand movement and strand damage in short twist pitch CICCs

    DOE PAGES

    Sanabria, Charlos; Lee, Peter J.; Starch, William; ...

    2015-10-14

    Prototype cable in conduit conductors (CICCs) destined for use in the Toroidal Field (TF) and Central Solenoid (CS) coils of the ITER experimental fusion reactor underwent severe cyclic loading in the SULTAN facility. Their autopsies revealed significant and permanent transverse strand migration due to the large Lorentz forces of the SULTAN test. The movement resulted in a 3 7% void fraction increase on the Low Pressure (LP) side of the longer twist pitch CICCs. However, short twist pitch conductors exhibited less than 1% void fraction increase in the LP side, as well as a complete absence of the Nb3Sn filamentmore » fractures observed in the longer twist pitch conductors. We report here a detailed strand to cable analysis of short and longer “baseline” twist pitch CICCs. It was found that the use of Internal Tin strands in the longer “baseline” twist pitch CICCs can be beneficial possibly because of their superior stiffness—which better resist strand movement—while the use of Bronze Process strands showed more movement and poorer cyclic test performance. This was not the case for the short twist pitch CICC. Such conductor design seems to work well with both strand types. But it was found that despite the absence of filament fractures, the short twist pitch CICC made from the Internal Tin strands studied here developed severe strand distortion during cabling which resulted in diffusion barrier breaks and Sn contamination of the Cu stabilizer during the heat treatment. Furthermore, the short twist pitch CICC made from Bronze Process strands preserved diffusion barrier integrity.« less

  15. Metallographic autopsies of full-scale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN: II. Significant reduction of strand movement and strand damage in short twist pitch CICCs

    SciTech Connect

    Sanabria, Charlos; Lee, Peter J.; Starch, William; Devred, Arnaud; Larbalestier, David C.

    2015-10-14

    Prototype cable in conduit conductors (CICCs) destined for use in the Toroidal Field (TF) and Central Solenoid (CS) coils of the ITER experimental fusion reactor underwent severe cyclic loading in the SULTAN facility. Their autopsies revealed significant and permanent transverse strand migration due to the large Lorentz forces of the SULTAN test. The movement resulted in a 3 7% void fraction increase on the Low Pressure (LP) side of the longer twist pitch CICCs. However, short twist pitch conductors exhibited less than 1% void fraction increase in the LP side, as well as a complete absence of the Nb3Sn filament fractures observed in the longer twist pitch conductors. We report here a detailed strand to cable analysis of short and longer “baseline” twist pitch CICCs. It was found that the use of Internal Tin strands in the longer “baseline” twist pitch CICCs can be beneficial possibly because of their superior stiffness—which better resist strand movement—while the use of Bronze Process strands showed more movement and poorer cyclic test performance. This was not the case for the short twist pitch CICC. Such conductor design seems to work well with both strand types. But it was found that despite the absence of filament fractures, the short twist pitch CICC made from the Internal Tin strands studied here developed severe strand distortion during cabling which resulted in diffusion barrier breaks and Sn contamination of the Cu stabilizer during the heat treatment. Furthermore, the short twist pitch CICC made from Bronze Process strands preserved diffusion barrier integrity.

  16. Comparison of Hybrid Capture II, Linear Array, and a Bead-Based Multiplex Genotyping Assay for Detection of Human Papillomavirus in Women with Negative Pap Test Results and Atypical Squamous Cells of Undetermined Significance

    PubMed Central

    Comar, Manola; Iannacone, Michelle R.; Casalicchio, Giorgia; McKay-Chopin, Sandrine; Tommasino, Massimo

    2012-01-01

    Many methods with different levels of analytical sensitivity and clinical specificity have been developed to detect the presence of high-risk (HR) types of the human papillomavirus (HPV) in cervical samples. The Hybrid Capture II (HC-II) assay is broadly used for primary screening. In addition, several HPV genotyping assays, based on PCR methods, display higher sensitivity than the HC-II and are also used in screening programs. We evaluated the performance of three HPV DNA tests, namely, the HC-II, the Linear Array (LA) HPV genotyping assay, and an HPV type-specific E7 PCR bead-based multiplex genotyping assay (TS-MPG) that is a laboratory-developed method for the detection of HPV, in 94 women with atypical squamous cells of undetermined significance (ASC-US) and in cytological samples from 86 women with a negative Pap test. The HPV prevalence with the TS-MPG assay was increased compared to the prevalence with the LA and HC-II assays. The HPV DNA prevalence in women with ASC-US was greater with the TS-MPG assay (46.2%) than with the LA (36.3%) and HC-II (29.7%) assays. The HPV DNA prevalence in the control group was greater with the TS-MPG assay (32.1%) than with the LA assay (10.7%). Two women with ASC-US who were HPV DNA negative by the HC-II and positive by the TS-MPG or/and LA assays had lesions that progressed to low-grade squamous intraepithelial and high-grade squamous intraepithelial lesions. This study shows that the TS-MPG assay exhibited higher analytical sensitivity than the LA and HC-II assays for the detection of HPV DNA, which reduces the potential to incorrectly identify a woman's HPV infection status. PMID:23035194

  17. Time series, periodograms, and significance

    NASA Astrophysics Data System (ADS)

    Hernandez, G.

    1999-05-01

    The geophysical literature shows a wide and conflicting usage of methods employed to extract meaningful information on coherent oscillations from measurements. This makes it difficult, if not impossible, to relate the findings reported by different authors. Therefore, we have undertaken a critical investigation of the tests and methodology used for determining the presence of statistically significant coherent oscillations in periodograms derived from time series. Statistical significance tests are only valid when performed on the independent frequencies present in a measurement. Both the number of possible independent frequencies in a periodogram and the significance tests are determined by the number of degrees of freedom, which is the number of true independent measurements, present in the time series, rather than the number of sample points in the measurement. The number of degrees of freedom is an intrinsic property of the data, and it must be determined from the serial coherence of the time series. As part of this investigation, a detailed study has been performed which clearly illustrates the deleterious effects that the apparently innocent and commonly used processes of filtering, de-trending, and tapering of data have on periodogram analysis and the consequent difficulties in the interpretation of the statistical significance thus derived. For the sake of clarity, a specific example of actual field measurements containing unevenly-spaced measurements, gaps, etc., as well as synthetic examples, have been used to illustrate the periodogram approach, and pitfalls, leading to the (statistical) significance tests for the presence of coherent oscillations. Among the insights of this investigation are: (1) the concept of a time series being (statistically) band limited by its own serial coherence and thus having a critical sampling rate which defines one of the necessary requirements for the proper statistical design of an experiment; (2) the design of a critical

  18. Choosing Outcomes of Significance.

    ERIC Educational Resources Information Center

    Spady, William G.

    1994-01-01

    Outcomes are high-quality, culminating demonstrations of significant learning in context. The High Success Network uses the "Demonstration Mountain" to differentiate among three major "learning zones" and six different forms of learning demonstrations that increase in complexity, generalizability, and significance, along with…

  19. Significant results: statistical or clinical?

    PubMed Central

    2016-01-01

    The null hypothesis significance test method is popular in biological and medical research. Many researchers have used this method for their research without exact knowledge, though it has both merits and shortcomings. Readers will know its shortcomings, as well as several complementary or alternative methods, as such the estimated effect size and the confidence interval. PMID:27066201

  20. Significance of periodogram peaks

    NASA Astrophysics Data System (ADS)

    Süveges, Maria; Guy, Leanne; Zucker, Shay

    2016-10-01

    Three versions of significance measures or False Alarm Probabilities (FAPs) for periodogram peaks are presented and compared for sinusoidal and box-like signals, with specific application on large-scale surveys in mind.

  1. Testing, Testing, Testing

    ERIC Educational Resources Information Center

    Coatney, Sharon

    2005-01-01

    Teacher-librarians and teachers said that testing is driving everything that they do. One elementary teacher said that her entire grade level had not been to the library all year because they did not have time because the testing is all consuming and dictating all they do in the classroom. The teacher-librarian at that school added there was…

  2. Significant natural areas

    Treesearch

    C. I. Millar; M. G. Barbour; D. L. Elliott-Fisk; J. R. Shevock; W. B. Woolfenden

    1996-01-01

    The Sierra Nevada Ecosystem Project mapped 945 areas in the Sierra Nevada of ecological, cultural, and geological significance. Theseareas contain outstanding features of unusual rarity, diversity, andrepresentativeness on national forest and national park lands. Morethan 70% of the areas were newly recognized during the SNEP project. Local agency specialists familiar...

  3. Significant Tsunami Events

    NASA Astrophysics Data System (ADS)

    Dunbar, P. K.; Furtney, M.; McLean, S. J.; Sweeney, A. D.

    2014-12-01

    Tsunamis have inflicted death and destruction on the coastlines of the world throughout history. The occurrence of tsunamis and the resulting effects have been collected and studied as far back as the second millennium B.C. The knowledge gained from cataloging and examining these events has led to significant changes in our understanding of tsunamis, tsunami sources, and methods to mitigate the effects of tsunamis. The most significant, not surprisingly, are often the most devastating, such as the 2011 Tohoku, Japan earthquake and tsunami. The goal of this poster is to give a brief overview of the occurrence of tsunamis and then focus specifically on several significant tsunamis. There are various criteria to determine the most significant tsunamis: the number of deaths, amount of damage, maximum runup height, had a major impact on tsunami science or policy, etc. As a result, descriptions will include some of the most costly (2011 Tohoku, Japan), the most deadly (2004 Sumatra, 1883 Krakatau), and the highest runup ever observed (1958 Lituya Bay, Alaska). The discovery of the Cascadia subduction zone as the source of the 1700 Japanese "Orphan" tsunami and a future tsunami threat to the U.S. northwest coast, contributed to the decision to form the U.S. National Tsunami Hazard Mitigation Program. The great Lisbon earthquake of 1755 marked the beginning of the modern era of seismology. Knowledge gained from the 1964 Alaska earthquake and tsunami helped confirm the theory of plate tectonics. The 1946 Alaska, 1952 Kuril Islands, 1960 Chile, 1964 Alaska, and the 2004 Banda Aceh, tsunamis all resulted in warning centers or systems being established.The data descriptions on this poster were extracted from NOAA's National Geophysical Data Center (NGDC) global historical tsunami database. Additional information about these tsunamis, as well as water level data can be found by accessing the NGDC website www.ngdc.noaa.gov/hazard/

  4. Composite Defect Significance.

    DTIC Science & Technology

    1982-07-13

    A12i 299 COMPOSITE DEFECT SIGNIFICANCE(U) MATERIALS SCIENCES 1/1 \\ CORP SPRING HOUSE PA S N CHATTERJEE ET AL. 13 JUL 82 MSC/TFR/1288/il87 NADC-80848...Directorate 30 Sensors & Avionics Technology Directorate 40 Communication & Navigation Technology Directorate 50 Software Computer Directorate 60 Aircraft ...instructions concerning commercial products herein do not constitute an endorsement by the Government nor do they convey or imply the license or right to use

  5. Significant event auditing.

    PubMed

    Pringle, M

    2000-12-01

    Significant event auditing has been described for 5 years and it is slowly gaining credibility as an effective method of quality assurance in British general practice. This paper describes what it is, what its background is, how it is done and whether it is effective. While it needs a positive team culture - and therefore may not suit every practice - where it is used it appears to be a useful adjunct to a clinical audit programme.

  6. Significance Analysis of Prognostic Signatures

    PubMed Central

    Beck, Andrew H.; Knoblauch, Nicholas W.; Hefti, Marco M.; Kaplan, Jennifer; Schnitt, Stuart J.; Culhane, Aedin C.; Schroeder, Markus S.; Risch, Thomas; Quackenbush, John; Haibe-Kains, Benjamin

    2013-01-01

    A major goal in translational cancer research is to identify biological signatures driving cancer progression and metastasis. A common technique applied in genomics research is to cluster patients using gene expression data from a candidate prognostic gene set, and if the resulting clusters show statistically significant outcome stratification, to associate the gene set with prognosis, suggesting its biological and clinical importance. Recent work has questioned the validity of this approach by showing in several breast cancer data sets that “random” gene sets tend to cluster patients into prognostically variable subgroups. This work suggests that new rigorous statistical methods are needed to identify biologically informative prognostic gene sets. To address this problem, we developed Significance Analysis of Prognostic Signatures (SAPS) which integrates standard prognostic tests with a new prognostic significance test based on stratifying patients into prognostic subtypes with random gene sets. SAPS ensures that a significant gene set is not only able to stratify patients into prognostically variable groups, but is also enriched for genes showing strong univariate associations with patient prognosis, and performs significantly better than random gene sets. We use SAPS to perform a large meta-analysis (the largest completed to date) of prognostic pathways in breast and ovarian cancer and their molecular subtypes. Our analyses show that only a small subset of the gene sets found statistically significant using standard measures achieve significance by SAPS. We identify new prognostic signatures in breast and ovarian cancer and their corresponding molecular subtypes, and we show that prognostic signatures in ER negative breast cancer are more similar to prognostic signatures in ovarian cancer than to prognostic signatures in ER positive breast cancer. SAPS is a powerful new method for deriving robust prognostic biological signatures from clinically annotated

  7. Significance of research.

    PubMed

    Kanpolat, Y

    2002-01-01

    The development of the central nervous system (CNS) in humans is the most important factor differentiating the human being from other species. Intelligence is the most important result of evolution of the CNS in humans. However, human intelligence is not a static factor, having evolved during the historical progression of cultural factors and educational systems. Since the Middle Ages, universities have been the most dominant open-society institutions to regulate intellectual influences, share scientific knowledge and values, and promote research in natural sciences. Research is particularly important in contemporary neurosurgery and neurological sciences with regard to the development of new techniques and testing of the acquired knowledge of the CNS. Research activities in neuroscience and neurosurgery have especially involved anatomical and functional aspects. However, advances in molecular biology and genetics have been remarkably effective in research activities in neurosciences. Such progress will help us to understand nature, environment and humans. Of course, research is now a domain of method, organisation and financial gain. The dedication, heroism and creativity which used to be the driving forces behind scientific research are now diminishing in value and are a source of controversy.

  8. Predicting significant torso trauma.

    PubMed

    Nirula, Ram; Talmor, Daniel; Brasel, Karen

    2005-07-01

    Identification of motor vehicle crash (MVC) characteristics associated with thoracoabdominal injury would advance the development of automatic crash notification systems (ACNS) by improving triage and response times. Our objective was to determine the relationships between MVC characteristics and thoracoabdominal trauma to develop a torso injury probability model. Drivers involved in crashes from 1993 to 2001 within the National Automotive Sampling System were reviewed. Relationships between torso injury and MVC characteristics were assessed using multivariate logistic regression. Receiver operating characteristic curves were used to compare the model to current ACNS models. There were a total of 56,466 drivers. Age, ejection, braking, avoidance, velocity, restraints, passenger-side impact, rollover, and vehicle weight and type were associated with injury (p < 0.05). The area under the receiver operating characteristic curve (83.9) was significantly greater than current ACNS models. We have developed a thoracoabdominal injury probability model that may improve patient triage when used with ACNS.

  9. Anthropological significance of phenylketonuria.

    PubMed

    Saugstad, L F

    1975-01-01

    The highest incidence rates of phenylketonuria (PKU) have been observed in Ireland and Scotlant. Parents heterozygous for PKU in Norway differ significantly from the general population in the Rhesus, Kell and PGM systems. The parents investigated showed an excess of Rh negative, Kell plus and PGM type 1 individuals, which makes them similar to the present populations in Ireland and Scotlant. It is postulated that the heterozygotes for PKU in Norway are descended from a completely assimilated sub-population of Celtic origin, who came or were brought here, 1ooo years ago. Bronze objects of Western European (Scottish, Irish) origin, found in Viking graves widely distributed in Norway, have been taken as evidence of Vikings returning with loot (including a number of Celts) from Western Viking settlements. The continuity of residence since the Viking age in most habitable parts of Norway, and what seems to be a nearly complete regional relationship between the sites where Viking graves contain western imported objects and the birthplaces of grandparents of PKUs identified in Norway, lend further support to the hypothesis that the heterozygotes for PKU in Norway are descended from a completely assimilated subpopulation. The remarkable resemblance between Iceland and Ireland, in respect of several genetic markers (including the Rhesus, PGM and Kell systems), is considered to be an expression of a similar proportion of people of Celtic origin in each of the two countries. Their identical, high incidence rates of PKU are regarded as further evidence of this. The significant decline in the incidence of PKU when one passes from Ireland, Scotland and Iceland, to Denmark and on to Norway and Sweden, is therefore explained as being related to a reduction in the proportion of inhabitants of Celtic extraction in the respective populations.

  10. Fungi producing significant mycotoxins.

    PubMed

    2012-01-01

    Mycotoxins are secondary metabolites of microfungi that are known to cause sickness or death in humans or animals. Although many such toxic metabolites are known, it is generally agreed that only a few are significant in causing disease: aflatoxins, fumonisins, ochratoxin A, deoxynivalenol, zearalenone, and ergot alkaloids. These toxins are produced by just a few species from the common genera Aspergillus, Penicillium, Fusarium, and Claviceps. All Aspergillus and Penicillium species either are commensals, growing in crops without obvious signs of pathogenicity, or invade crops after harvest and produce toxins during drying and storage. In contrast, the important Fusarium and Claviceps species infect crops before harvest. The most important Aspergillus species, occurring in warmer climates, are A. flavus and A. parasiticus, which produce aflatoxins in maize, groundnuts, tree nuts, and, less frequently, other commodities. The main ochratoxin A producers, A. ochraceus and A. carbonarius, commonly occur in grapes, dried vine fruits, wine, and coffee. Penicillium verrucosum also produces ochratoxin A but occurs only in cool temperate climates, where it infects small grains. F. verticillioides is ubiquitous in maize, with an endophytic nature, and produces fumonisins, which are generally more prevalent when crops are under drought stress or suffer excessive insect damage. It has recently been shown that Aspergillus niger also produces fumonisins, and several commodities may be affected. F. graminearum, which is the major producer of deoxynivalenol and zearalenone, is pathogenic on maize, wheat, and barley and produces these toxins whenever it infects these grains before harvest. Also included is a short section on Claviceps purpurea, which produces sclerotia among the seeds in grasses, including wheat, barley, and triticale. The main thrust of the chapter contains information on the identification of these fungi and their morphological characteristics, as well as factors

  11. Human Papillomavirus (HPV) DNA Triage of Women with Atypical Squamous Cells of Undetermined Significance with cobas 4800 HPV and Hybrid Capture 2 Tests for Detection of High-Grade Lesions of the Uterine Cervix

    PubMed Central

    Lapierre, Simon Grandjean; Sauthier, Philippe; Mayrand, Marie-Hélène; Dufresne, Simon; Petignat, Patrick; Provencher, Diane; Drouin, Pierre; Gauthier, Philippe; Dupuis, Marie-Josée; Michon, Bertrand; Ouellet, Stéphan; Hadjeres, Rachid; Ferenczy, Alex; Franco, Eduardo L.

    2012-01-01

    The triage of women with high-risk (HR) human papillomavirus (HPV)-positive smears for atypical squamous cells of undetermined significance (ASC-US) to colposcopy is now an integrated option in clinical guidelines. The performance of cobas 4800 HPV and that of Hybrid Capture 2 (HC2) for HR HPV DNA detection in cervical samples in PreservCyt were compared in 396 women referred to colposcopy for ASC-US. Of these, 316 did not have cervical intraepithelial neoplasia (CIN), 47 had CIN1, 29 had CIN2 or CIN3 (CIN2+), and 4 had CIN of unknown grade. HR HPV was detected in 129 (32.6%) and 149 (37.6%) samples with HC2 and cobas 4800 HPV, respectively (P = 0.15). The clinical sensitivities and specificities for detecting CIN2+ were 89.7% (95% confidence interval [CI], 72.8 to 97.2%) and 66.7% (95% CI, 61.7 to 71.3%) with cobas 4800 HPV and 93.1% (95% CI, 77.0 to 99.2%) and 72.2% (95% CI 67.4 to 76.5%) with HC2. The performance of cobas 4800 HPV was similar to that of HC2 for identifying women with ASC-US who would benefit the most from colposcopy. PMID:22301023

  12. Significances of Multimedia Technologies Training

    NASA Astrophysics Data System (ADS)

    Zhang, Fulei

    The use of multimedia technologies in education has enabled teachers to simulate final outcomes and assist s-tudents in applying knowledge learned from textbooks, thereby compensating for the deficiency of traditional teach- ing methods. It is important to examine how effective these technologies are in practical use. This study developed online learning-teaching resource platforms using Flash multimedia, providing interactive and integrated features in an easy-to-use user interface, in order to discuss Computer-Aided Drawing (CAD). The study utilized a teaching experiment with a non-equivalent pretest-posttest control group design to test and discuss students' professional cognition, operating skill cognition, and level of learning satisfaction during the learning process. No significant differences emerged between the groups in regards to professional cognition or operation skills cognition. However, a significant difference in learning satisfaction was noted, indicating that the coursework with multimedia Flash produced greater satisfaction than with traditional learning methods. Results are explained in detail and recommendations for further research provided.

  13. Testing the functional significance of microbial community composition.

    Treesearch

    Michael S. Strickland; Christian Lauber; Noah Fierer; Mark A. Bradford

    2009-01-01

    A critical assumption underlying terrestrial ecosystem models is that soil microbial communities, when placed in a common environment, will function in an identical manner regardless of the composition...

  14. The significance of mitochondrial toxicity testing in drug development.

    PubMed

    Dykens, James A; Will, Yvonne

    2007-09-01

    Mitochondrial dysfunction is increasingly implicated in the etiology of drug-induced toxicities. Members of diverse drug classes undermine mitochondrial function, and among the most potent are drugs that have been withdrawn from the market, or have received Black Box warnings from the FDA. To avoid mitochondrial liabilities, routine screens need to be positioned within the drug-development process. Assays for mitochondrial function, cell models that better report mitochondrial impairment, and new animal models that more faithfully reflect clinical manifestations of mitochondrial dysfunction are discussed in the context of how such data can reduce late stage attrition of drug candidates and can yield safer drugs in the future.

  15. 31 CFR 561.328 - Reduce significantly, significantly reduced, and significant reduction.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Reduce significantly, significantly reduced, and significant reduction. 561.328 Section 561.328 Money and Finance: Treasury Regulations... reduced, and significant reduction. The terms reduce significantly, significantly reduced, and significant...

  16. 31 CFR 561.328 - Reduce significantly, significantly reduced, and significant reduction.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Reduce significantly, significantly reduced, and significant reduction. 561.328 Section 561.328 Money and Finance: Treasury Regulations... reduced, and significant reduction. The terms reduce significantly, significantly reduced, and significant...

  17. Efficient approximation of P-value of the maximum of correlated tests, with applications to genome-wide association studies.

    PubMed

    Li, Qizhai; Zheng, Gang; Li, Zhaohai; Yu, Kai

    2008-05-01

    Genome-wide association study (GWAS), typically involving 100,000 to 500,000 single-nucleotide polymorphisms (SNPs), is a powerful approach to identify disease susceptibility loci. In a GWAS, single-marker analysis, which tests one SNP at a time, is usually used as the first stage to screen SNPs across the genome in order to identify a small fraction of promising SNPs with relatively low p-values for further and more focused studies. For single-marker analysis, the trend test derived for an additive genetic model is often used. This may not be robust when the additive assumption is not appropriate for the true underlying disease model. A robust test, MAX, based on the maximum of three trend test statistics derived for recessive, additive, and dominant models, has been proposed recently for GWAS. But its p-value has to be evaluated through a resampling-based procedure, which is computationally challenging for the analysis of GWAS. Obtaining the p-value for MAX with adjustment for the covariates can be even more time-consuming. In this article, we provide a simple approximation for the p-value of the MAX test with or without adjusting for the covariates. The new method avoids resampling steps and thus makes the MAX test readily applicable to GWAS. We use simulation studies as well as real datasets on 17 confirmed disease-associated SNPs to assess the accuracy of the proposed method. We also apply the method to the GWAS of coronary artery disease.

  18. Significance Alone Is Not Enough.

    ERIC Educational Resources Information Center

    Michalczyk, Alan E.; Lewis, Lloyd A.

    1980-01-01

    Thirty-three research articles based on t-tests, F-tests, or Pearson product-moment correlations selected from the "Journal of Medical Education" were examined for adequate research reporting. Nearly one-half did not report sufficient data or were found to have low power values. Guidelines for research reporting are discussed.…

  19. Sanitary Surveys & Significant Deficiencies Presentation

    EPA Pesticide Factsheets

    The Sanitary Surveys & Significant Deficiencies Presentation highlights some of the things EPA looks for during drinking water system site visits, how to avoid significant deficiencies and what to do if you receive one.

  20. [Preliminary identification of clinically significant Clostridium species].

    PubMed

    Balejová, Magda

    2010-06-01

    Preliminary identification of clinically significant Clostridium spp. is based on evaluating their microscopic and macroscopic morphology, Gram staining (Gram stain-positive structure of the bacterial wall), positive production of lecithinase, lipase and proteolytic activity on egg yolk agar, and simple chemical tests. If this preliminary identification is not sufficient, biochemical identification is performed, along with 16S-rRNA sequencing of the bacterial genome. The article comments on options of preliminary identification of clinically significant Clostridium spp.

  1. Can Educationally Significant Learning Be Assessed?

    ERIC Educational Resources Information Center

    Stolz, Steven A.

    2017-01-01

    This article argues that assessment is a central feature of teaching, particularly as a means to determine whether what has been taught has been learnt. However, I take issue with the current trend in education which places a significant amount of emphasis upon large-scale public testing, which in turn has exacerbated the…

  2. Significant New Alternatives Policy (SNAP)

    EPA Pesticide Factsheets

    These webpages provide information on EPA’s Significant New Alternatives Policy (SNAP) program which evaluates substitutes for ozone-depleting substances in major industrial use sectors. The SNAP program promotes a smooth transition to safer alternatives.

  3. Alternative Significant Contribution Approaches Evaluated

    EPA Pesticide Factsheets

    This Technical Support Document (TSD) discusses alternative approaches that EPA evaluated for defining emissions that constitute each upwind state’s significant contribution to nonattainment and interference with maintenance downwind.

  4. Astronomical Significance of Ancient Monuments

    NASA Astrophysics Data System (ADS)

    Simonia, I.

    2011-06-01

    Astronomical significance of Gokhnari megalithic monument (eastern Georgia) is considered. Possible connection of Amirani ancient legend with Gokhnari monument is discussed. Concepts of starry practicality and solar stations are proposed.

  5. Significant Decisions in Labor Cases.

    ERIC Educational Resources Information Center

    Monthly Labor Review, 1979

    1979-01-01

    Several significant court decisions involving labor cases are discussed including a series of decisions concerning constitutional protections afforded aliens; the First Amendment and national labor relations laws; and the bifurcated backpay rule. (BM)

  6. Significant Scales in Community Structure

    PubMed Central

    Traag, V. A.; Krings, G.; Van Dooren, P.

    2013-01-01

    Many complex networks show signs of modular structure, uncovered by community detection. Although many methods succeed in revealing various partitions, it remains difficult to detect at what scale some partition is significant. This problem shows foremost in multi-resolution methods. We here introduce an efficient method for scanning for resolutions in one such method. Additionally, we introduce the notion of “significance” of a partition, based on subgraph probabilities. Significance is independent of the exact method used, so could also be applied in other methods, and can be interpreted as the gain in encoding a graph by making use of a partition. Using significance, we can determine “good” resolution parameters, which we demonstrate on benchmark networks. Moreover, optimizing significance itself also shows excellent performance. We demonstrate our method on voting data from the European Parliament. Our analysis suggests the European Parliament has become increasingly ideologically divided and that nationality plays no role. PMID:24121597

  7. Significant Decisions in Labor Cases.

    ERIC Educational Resources Information Center

    Monthly Labor Review, 1979

    1979-01-01

    Several significant court decisions involving labor cases are discussed including a series of decisions concerning constitutional protections afforded aliens; the First Amendment and national labor relations laws; and the bifurcated backpay rule. (BM)

  8. Analysis to Quantify Significant Contribution

    EPA Pesticide Factsheets

    This Technical Support Document provides information that supports EPA’s analysis to quantify upwind state emissions that significantly contribute to nonattainment or interfere with maintenance of National Ambient Air Quality Standards in downwind states.

  9. Statistical Significance vs. Practical Significance: An Exploration through Health Education

    ERIC Educational Resources Information Center

    Rosen, Brittany L.; DeMaria, Andrea L.

    2012-01-01

    The purpose of this paper is to examine the differences between statistical and practical significance, including strengths and criticisms of both methods, as well as provide information surrounding the application of various effect sizes and confidence intervals within health education research. Provided are recommendations, explanations and…

  10. Status and Significance of Credentialing.

    ERIC Educational Resources Information Center

    Musgrave, Dorothea

    1984-01-01

    Discusses the current status, significance, and future of credentialing in the field of environmental health. Also discusses four phases of a Bureau of Health Professions (BHP) Credentialing Program and BHP-funded projects related to their development and implementation. Phases include role delineation, resources development, examination…

  11. The historical significance of oak

    Treesearch

    J. V. Thirgood

    1971-01-01

    A brief history of the importance of oak in Europe, contrasting the methods used in France and Britain to propagate the species and manage the forests for continued productivity. The significance of oak as a strategic resource during the sailing-ship era is stressed, and mention is made of the early development of oak management in North America. The international...

  12. Statistical Significance of Threading Scores

    PubMed Central

    Fayyaz Movaghar, Afshin; Launay, Guillaume; Schbath, Sophie; Gibrat, Jean-François

    2012-01-01

    Abstract We present a general method for assessing threading score significance. The threading score of a protein sequence, thread onto a given structure, should be compared with the threading score distribution of a random amino-acid sequence, of the same length, thread on the same structure; small p-values point significantly high scores. We claim that, due to general protein contact map properties, this reference distribution is a Weibull extreme value distribution whose parameters depend on the threading method, the structure, the length of the query and the random sequence simulation model used. These parameters can be estimated off-line with simulated sequence samples, for different sequence lengths. They can further be interpolated at the exact length of a query, enabling the quick computation of the p-value. PMID:22149633

  13. Which Reconstruction Results are Significant?

    DTIC Science & Technology

    1980-05-01

    other significant result is due to Tutte [17]. Tutte’s Theorem: The characteristic polynomial of a graph can be reconstructed. Equivalently, two...hypomorphic graphs must have the same characteristic polynomial . Several points should be noted concerning this theorem: 1. The derivative of the...characteristic polynomial is the sum of the char- acteristic polynomials of the vertex-deleted subgraphs. Thus the characteristic polynomials of hypomorphic

  14. Prognostic significance of double product and inadequate double product response to maximal symptom-limited exercise stress testing after myocardial infarction in 6296 patients treated with thrombolytic agents. GISSI-2 Investigators. Grupo Italiano per lo Studio della Sopravvivenza nell-Infarto Miocardico.

    PubMed

    Villella, M; Villella, A; Barlera, S; Franzosi, M G; Maggioni, A P

    1999-03-01

    The aim of this study was to evaluate the prognostic significance of the pressure-rate product (PRP) obtained during exercise stress testing and of its change from rest to maximal exercise (dPRP) in a population of survivors of acute myocardial infarction treated with thrombolytic agents. Survivors of acute myocardial infarction (n = 6251) from the GISSI-2 database, who underwent a maximal symptom-limited exercise test with either bicycle ergometer or treadmill, were followed up for 6 months. PRP and dPRP values were dichotomized (21,700, 11,600, respectively) and analyzed in a multivariate Cox model individually and simultaneously with other ergometric variables. Six-month mortality rate was 0.8% in the high PRP group and 2.0% in the low PRP group. Low PRP was an independent predictor of 6-month mortality rate (relative risk [RR] 1.97, 95% confidence interval [CI] 1.24 to 3.13). Patients with low dPRP had mortality rates higher than patients with high dPRP (2.1% vs 0.8%). At the multivariate analysis, low dPRP showed negative predictive value (RR 1.97, 95% CI 1.23 to 3.16). A further multivariate analysis was performed with PRP and dPRP, also adjusting for low work capacity, abnormal systolic blood pressure response to exercise, and symptomatic-induced ischemia. The results showed that low work capacity, low PRP, and symptomatic exercise-induced ischemia were still significantly associated with higher 6-month mortality rate (P =.04,.02, and.05; RR = 1.68, 1.71, and 1.78 respectively). PRP is a predictive index to assess prognosis in survivors of acute myocardial infarction treated with thrombolytic agents able to perform an exercise test after acute myocardial infarction, but its usefulness appears to be limited, considering that these patients were at low risk.

  15. Where boosted significances come from

    NASA Astrophysics Data System (ADS)

    Plehn, Tilman; Schichtel, Peter; Wiegand, Daniel

    2014-03-01

    In an era of increasingly advanced experimental analysis techniques it is crucial to understand which phase space regions contribute a signal extraction from backgrounds. Based on the Neyman-Pearson lemma we compute the maximum significance for a signal extraction as an integral over phase space regions. We then study to what degree boosted Higgs strategies benefit ZH and tt¯H searches and which transverse momenta of the Higgs are most promising. We find that Higgs and top taggers are the appropriate tools, but would profit from a targeted optimization towards smaller transverse momenta. MadMax is available as an add-on to MadGraph 5.

  16. PSD Significance Levels for Monitoring

    EPA Pesticide Factsheets

    This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

  17. Clinical significance of neonatal menstruation.

    PubMed

    Brosens, Ivo; Benagiano, Giuseppe

    2016-01-01

    Past studies have clearly shown the existence of a spectrum of endometrial progesterone responses in neonatal endometrium, varying from proliferation to full decidualization with menstrual-like shedding. The bleedings represent, similar to what occurs in adult menstruation, a progesterone withdrawal bleeding. Today, the bleeding is completely neglected and considered an uneventful episode of no clinical significance. Yet clinical studies have linked the risk of bleeding to a series of events indicating fetal distress. The potential link between the progesterone response and major adolescent disorders requires to be investigated by prospective studies. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  18. Significance of biofilms in dentistry.

    PubMed

    Wróblewska, Marta; Strużycka, Izabela; Mierzwińska-Nastalska, Elżbieta

    2015-01-01

    In the past decades significant scientific progress has taken place in the knowledge about biofilms. They constitute multilayer conglomerates of bacteria and fungi, surrounded by carbohydrates which they produce, as well as substances derived from saliva and gingival fluid. Modern techniques showed significant diversity of the biofilm environment and a system of microbial communication (quorum sensing), enhancing their survival. At present it is believed that the majority of infections, particularly chronic with exacerbations, are a result of biofilm formation, particularly in the presence of biomaterials. It should be emphasised that penetration of antibiotics and other antimicrobial agents into deeper layers of a biofilm is poor, causing therapeutic problems and necessitating sometimes removal of the implant or prosthesis. Biofilms play an increasing role in dentistry as a result of more and more broad use in dental practice of plastic and implantable materials. Biofilms are produced on the surfaces of teeth as dental plaque, in the para-nasal sinuses, on prostheses, dental implants, as well as in waterlines of a dental unit, constituting a particular risk for severely immunocompromised patients. New methods of therapy and prevention of infections linked to biofilms are under development.

  19. Public health significance of neuroticism.

    PubMed

    Lahey, Benjamin B

    2009-01-01

    The personality trait of neuroticism refers to relatively stable tendencies to respond with negative emotions to threat, frustration, or loss. Individuals in the population vary markedly on this trait, ranging from frequent and intense emotional reactions to minor challenges to little emotional reaction even in the face of significant difficulties. Although not widely appreciated, there is growing evidence that neuroticism is a psychological trait of profound public health significance. Neuroticism is a robust correlate and predictor of many different mental and physical disorders, comorbidity among them, and the frequency of mental and general health service use. Indeed, neuroticism apparently is a predictor of the quality and longevity of our lives. Achieving a full understanding of the nature and origins of neuroticism, and the mechanisms through which neuroticism is linked to mental and physical disorders, should be a top priority for research. Knowing why neuroticism predicts such a wide variety of seemingly diverse outcomes should lead to improved understanding of commonalities among those outcomes and improved strategies for preventing them.

  20. Public Health Significance of Neuroticism

    PubMed Central

    Lahey, Benjamin B.

    2009-01-01

    The personality trait of neuroticism refers to relatively stable tendencies to respond with negative emotions to threat, frustration, or loss. Individuals in the population vary markedly on this trait, ranging from frequent and intense emotional reactions to minor challenges to little emotional reaction even in the face of significant difficulties. Although not widely appreciated, there is growing evidence that neuroticism is a psychological trait of profound public health significance. Neuroticism is a robust correlate and predictor of many different mental and physical disorders, comorbidity among them, and the frequency of mental and general health service use. Indeed, neuroticism apparently is a predictor of the quality and longevity of our lives. Achieving a full understanding of the nature and origins of neuroticism, and the mechanisms through which neuroticism is linked to mental and physical disorders, should be a top priority for research. Knowing why neuroticism predicts such a wide variety of seemingly diverse outcomes should lead to improved understanding of commonalities among those outcomes and improved strategies for preventing them. PMID:19449983

  1. The adaptive significance of sexuality.

    PubMed

    Bremermann, H J

    1987-01-01

    The theory predicts that inbred strains of mice are susceptible to tumor viruses that have escaped immune recognition. The theory implies routine evolutionary extinction of asexual species and that existing parthenogenetic species would have to have evolved recently from sexually reproducing precursors. This could be tested by determining the amount of DNA divergence between parthenogenetic and related sexually reproducing species. In mammals and birds genetic substitutions occur at comparable rates, but the AIDS virus evolves about 10 million times more rapidly. This confirms the basic imbalance of rates of evolution between microparasites and metazoan hosts, which is fundamental to the theory. The organization of most eukaryotic genes into exons and introns facilitates the generation of variety of gene products, and the molecular mechanism is similar to the mechanism that generates antibody diversity in the immune response and antigenic variation in trypanosomes. It has been proposed that noncoding 'selfish' DNA is the ultimate sexually transmitted disease. If this were the case, then asexually reproducing species would have an added advantage. An alternative hypothesis is proposed: noncoding DNA could provide insertion sites for retroviruses that would prevent them from being transcribed and replicated and thus moderate their proliferation much as absorber rods moderate proliferation of neutrons in a nuclear reactor. Flowering plants have pollen selection mechanisms that enforce heterozygosity at one or more loci. It has been proposed that analogous sperm selection mechanisms exist in mammals. Such a process would account for observation of a mysterious excess molecular divergence between different strains of inbred mice.

  2. Pathological Significance of Mitochondrial Glycation

    PubMed Central

    Pun, Pamela Boon Li; Murphy, Michael P.

    2012-01-01

    Glycation, the nonenzymatic glycosylation of biomolecules, is commonly observed in diabetes and ageing. Reactive dicarbonyl species such as methylglyoxal and glyoxal are thought to be major physiological precursors of glycation. Because these dicarbonyls tend to be formed intracellularly, the levels of advanced glycation end products on cellular proteins are higher than on extracellular ones. The formation of glycation adducts within cells can have severe functional consequences such as inhibition of protein activity and promotion of DNA mutations. Although several lines of evidence suggest that there are specific mitochondrial targets of glycation, and mitochondrial dysfunction itself has been implicated in disease and ageing, it is unclear if glycation of biomolecules specifically within mitochondria induces dysfunction and contributes to disease pathology. We discuss here the possibility that mitochondrial glycation contributes to disease, focussing on diabetes, ageing, cancer, and neurodegeneration, and highlight the current limitations in our understanding of the pathological significance of mitochondrial glycation. PMID:22778743

  3. [Hypertriglyceridemia: concept and clinical significance].

    PubMed

    Hirano, Tsutomu

    2013-09-01

    Hypertriglyceridemia is a common lipid disorder as well as hypercholesterolemia. However clinical significance of hypertriglyceridemia is not fully understood because of its heterogeneous lipoprotein phenotypes and complex etiology. Severe hypertriglyceridemia increases the risk for pancreatitis, whereas mild or moderate hypertriglyceridemia may be a risk factor for cardiovascular disease. Patients with hypertriglyceridemia are usually accompanied by other cardiovascular related disorders, such as central obesity, type 2 diabetes, and liver steatosis. Ectopic fat accumulation is often seen in hypertriglyceridemic subjects and various organ injuries are developed by the lipotoxicity. Hypertriglyceridemia is strongly associated with remnant lipoprotein accumulation, increased small dense LDL, and low HDL-cholesterol. All these lipid abnormalities are recognized as cardiovascular risk factors. The pathophysiology of lipoprotein metabolism related to the hypertriglyceridemia is summarized in this brief review.

  4. The significance of small streams

    NASA Astrophysics Data System (ADS)

    Wohl, Ellen

    2017-09-01

    Headwaters, defined here as first- and secondorder streams, make up 70%‒80% of the total channel length of river networks. These small streams exert a critical influence on downstream portions of the river network by: retaining or transmitting sediment and nutrients; providing habitat and refuge for diverse aquatic and riparian organisms; creating migration corridors; and governing connectivity at the watershed-scale. The upstream-most extent of the channel network and the longitudinal continuity and lateral extent of headwaters can be difficult to delineate, however, and people are less likely to recognize the importance of headwaters relative to other portions of a river network. Consequently, headwaters commonly lack the legal protections accorded to other portions of a river network and are more likely to be significantly altered or completely obliterated by land use.

  5. Yawning and its physiological significance

    PubMed Central

    Gupta, Sharat; Mittal, Shallu

    2013-01-01

    Although yawning is a commonly witnessed human behavior, yet it has not been taught in much detail in medical schools because, until the date, no particular physiological significance has been associated with it. It is characterized by opening up of mouth which is accompanied by a long inspiration, with a brief interruption of ventilation and followed by a short expiration. Since time immemorial, yawning has been associated with drowsiness and boredom. However, this age old belief is all set to change as the results of some newer studies have pointed out that yawning might be a way by which our body is trying to accomplish some more meaningful goals. In this review, we have tried to put together some of the important functions that have been proposed by a few authors, with the hope that this article will stimulate the interest of newer researchers in this hitherto unexplored field. PMID:23776833

  6. Statistical significance versus clinical relevance.

    PubMed

    van Rijn, Marieke H C; Bech, Anneke; Bouyer, Jean; van den Brand, Jan A J G

    2017-04-01

    In March this year, the American Statistical Association (ASA) posted a statement on the correct use of P-values, in response to a growing concern that the P-value is commonly misused and misinterpreted. We aim to translate these warnings given by the ASA into a language more easily understood by clinicians and researchers without a deep background in statistics. Moreover, we intend to illustrate the limitations of P-values, even when used and interpreted correctly, and bring more attention to the clinical relevance of study findings using two recently reported studies as examples. We argue that P-values are often misinterpreted. A common mistake is saying that P < 0.05 means that the null hypothesis is false, and P ≥0.05 means that the null hypothesis is true. The correct interpretation of a P-value of 0.05 is that if the null hypothesis were indeed true, a similar or more extreme result would occur 5% of the times upon repeating the study in a similar sample. In other words, the P-value informs about the likelihood of the data given the null hypothesis and not the other way around. A possible alternative related to the P-value is the confidence interval (CI). It provides more information on the magnitude of an effect and the imprecision with which that effect was estimated. However, there is no magic bullet to replace P-values and stop erroneous interpretation of scientific results. Scientists and readers alike should make themselves familiar with the correct, nuanced interpretation of statistical tests, P-values and CIs. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

  7. Statistically significant relational data mining :

    SciTech Connect

    Berry, Jonathan W.; Leung, Vitus Joseph; Phillips, Cynthia Ann; Pinar, Ali; Robinson, David Gerald; Berger-Wolf, Tanya; Bhowmick, Sanjukta; Casleton, Emily; Kaiser, Mark; Nordman, Daniel J.; Wilson, Alyson G.

    2014-02-01

    This report summarizes the work performed under the project (3z(BStatitically significant relational data mining.(3y (BThe goal of the project was to add more statistical rigor to the fairly ad hoc area of data mining on graphs. Our goal was to develop better algorithms and better ways to evaluate algorithm quality. We concetrated on algorithms for community detection, approximate pattern matching, and graph similarity measures. Approximate pattern matching involves finding an instance of a relatively small pattern, expressed with tolerance, in a large graph of data observed with uncertainty. This report gathers the abstracts and references for the eight refereed publications that have appeared as part of this work. We then archive three pieces of research that have not yet been published. The first is theoretical and experimental evidence that a popular statistical measure for comparison of community assignments favors over-resolved communities over approximations to a ground truth. The second are statistically motivated methods for measuring the quality of an approximate match of a small pattern in a large graph. The third is a new probabilistic random graph model. Statisticians favor these models for graph analysis. The new local structure graph model overcomes some of the issues with popular models such as exponential random graph models and latent variable models.

  8. Polysaccharides: Occurrence, Significance, and Properties

    NASA Astrophysics Data System (ADS)

    Bemiller, James N.

    Polysaccharides are properties present significance in all living organisms where they carry out one or more of their diverse functions. While there is no specific category or definition of a complex polysaccharide, most are structurally complex. Polysaccharides contain 1-5 different monosaccharide (sugar) units. The different sugar units may have different anomeric configurations and/or be joined by different glycosidic linkages. Polysaccharides may be linear or branched. Branches may be short saccharide units on a linear backbone or the molecule may have a branch-on-branch structure; in either case, the branches may be isolated or clustered. Polysaccharides may contain non-carbohydrate groups. Esters or cyclic acetal groups, when present, can be removed by appropriate treatments. All polysaccharides are polydisperse, i. e., are present in a range of molecular weights rather than having a single molecular weight. Most are polymolecular, i. e., differ in fine structure from molecule to molecule. So most polysaccharides can be said to be structurally complex. They may be attached to protein molecules or to other polysaccharide molecules. They are solvated by water. Most dissolve in aqueous systems, especially if they are alkaline. Polysaccharides can be depolymerized by acids and heat, specific enzymes, and high pH systems following oxidation. Their hydroxyl groups can be esterified (acylated), etherified (alkylated), and oxidized. Amino groups can be acylated (and deacylated). Carboxyl groups can be converted into esters, amides, and amines. Structural modification makes the molecules even more complex and polymolecular and, perhaps, polydisperse.

  9. Clinical significance of monocyte heterogeneity.

    PubMed

    Stansfield, Brian K; Ingram, David A

    2015-01-01

    Monocytes are primitive hematopoietic cells that primarily arise from the bone marrow, circulate in the peripheral blood and give rise to differentiated macrophages. Over the past two decades, considerable attention to monocyte diversity and macrophage polarization has provided contextual clues into the role of myelomonocytic derivatives in human disease. Until recently, human monocytes were subdivided based on expression of the surface marker CD16. "Classical" monocytes express surface markers denoted as CD14(++)CD16(-) and account for greater than 70% of total monocyte count, while "non-classical" monocytes express the CD16 antigen with low CD14 expression (CD14(+)CD16(++)). However, recognition of an intermediate population identified as CD14(++)CD16(+) supports the new paradigm that monocytes are a true heterogeneous population and careful identification of specific subpopulations is necessary for understanding monocyte function in human disease. Comparative studies of monocytes in mice have yielded more dichotomous results based on expression of the Ly6C antigen. In this review, we will discuss the use of monocyte subpopulations as biomarkers of human disease and summarize correlative studies in mice that may yield significant insight into the contribution of each subset to disease pathogenesis.

  10. Determining Semantically Related Significant Genes.

    PubMed

    Taha, Kamal

    2014-01-01

    GO relation embodies some aspects of existence dependency. If GO term xis existence-dependent on GO term y, the presence of y implies the presence of x. Therefore, the genes annotated with the function of the GO term y are usually functionally and semantically related to the genes annotated with the function of the GO term x. A large number of gene set enrichment analysis methods have been developed in recent years for analyzing gene sets enrichment. However, most of these methods overlook the structural dependencies between GO terms in GO graph by not considering the concept of existence dependency. We propose in this paper a biological search engine called RSGSearch that identifies enriched sets of genes annotated with different functions using the concept of existence dependency. We observe that GO term xcannot be existence-dependent on GO term y, if x- and y- have the same specificity (biological characteristics). After encoding into a numeric format the contributions of GO terms annotating target genes to the semantics of their lowest common ancestors (LCAs), RSGSearch uses microarray experiment to identify the most significant LCA that annotates the result genes. We evaluated RSGSearch experimentally and compared it with five gene set enrichment systems. Results showed marked improvement.

  11. Astrobiological Significance of Chemolithoautotrophic Acidophiles

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena V.; Hoover, Richard B.

    2003-01-01

    For more than a century (since Winogradsky discovered lithoautotrophic bacteria) a dilemma in microbiology has concerned life that first inhabited the Earth. Which types of life forms first appeared in the primordial oceans during the earliest geological period on Earth as the primary ancestors of modem biological diversity? How did a metabolism of ancestors evolve: from lithoautotrophic to lithohetherotrophic and organoheterotrophic or from organoheterotrophic to organoautotrophic and lithomixotrophic types? At the present time, it is known that chemolithoheterotrophic and chemolithoautotrophic metabolizing bacteria are wide spread in different ecosystems. On Earth the acidic ecosystems are associated with geysers, volcanic fumaroles, hot springs, deep sea hydrothermal vents, caves, acid mine drainage and other technogenic ecosystems. Bioleaching played a significant role on a global geological scale during the Earth's formation. This important feature of bacteria has been successfully applied in industry. The lithoautotrophs include Bacteria and Archaea belonging to diverse genera containing thermophilic and mesophilic species. In this paper we discuss the lithotrophic microbial acidophiles and present some data with a description of new acidophilic iron- and sulfur- oxidizing bacterium isolated from the Chena Hot Springs in Alaska. We also consider the possible relevance of microbial acidophiles to Venus, Io, and acidic inclusions in glaciers and icy moons.

  12. Astrobiological Significance of Chemolithoautotrophic Acidophiles

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena V.; Hoover, Richard B.

    2003-01-01

    For more than a century (since Winogradsky discovered lithoautotrophic bacteria) a dilemma in microbiology has concerned life that first inhabited the Earth. Which types of life forms first appeared in the primordial oceans during the earliest geological period on Earth as the primary ancestors of modem biological diversity? How did a metabolism of ancestors evolve: from lithoautotrophic to lithohetherotrophic and organoheterotrophic or from organoheterotrophic to organoautotrophic and lithomixotrophic types? At the present time, it is known that chemolithoheterotrophic and chemolithoautotrophic metabolizing bacteria are wide spread in different ecosystems. On Earth the acidic ecosystems are associated with geysers, volcanic fumaroles, hot springs, deep sea hydrothermal vents, caves, acid mine drainage and other technogenic ecosystems. Bioleaching played a significant role on a global geological scale during the Earth's formation. This important feature of bacteria has been successfully applied in industry. The lithoautotrophs include Bacteria and Archaea belonging to diverse genera containing thermophilic and mesophilic species. In this paper we discuss the lithotrophic microbial acidophiles and present some data with a description of new acidophilic iron- and sulfur- oxidizing bacterium isolated from the Chena Hot Springs in Alaska. We also consider the possible relevance of microbial acidophiles to Venus, Io, and acidic inclusions in glaciers and icy moons.

  13. [The significance of antiphospholipid antibodies].

    PubMed

    Fojtík, Z

    2004-04-01

    Antiphospholipid antibodies (APLA) present very heterogeneous groups of antibodies which can significantly influence processes on different levels of coagulation cascade depending on effects of phospholipid surfaces on blood coagulation. This usually leads to a particular level of thrombophylia. Clinical syndrome accompanying positive APLA, such as antiphospholipid syndrome, was defined by clinical and laboratory symptoms. This clinical syndrome can be a primary syndrome, if other disorders with ability to induce generation of antibodies can be excluded, or a secondary syndrome. The most often in cases of systemic tissue disease. APLA can be divided according to the presence of lupus anticoagulant and anticardiolipin antibodies. According to a definition lupus anticoagulants are antibodies able to inhibit and prolong in vitro one or more blood clotting processes dependent on phospholipid surfaces. Anticardiolipin antibodies are antibodies measured by ELISA method with cardiolipin used as an antibody. Findings show that some APLA are directed against proteins bound to phospholipid surfaces. Main cofactor proteins include beta 2-GPI and prothrombin. Because of their heterogeneous specificity, APLA are directed against negative phospholipids or proteins bound to phospholipid surfaces and have important pathophysiology role in development of antiphospholipid syndrome.

  14. Detection of significant protein coevolution.

    PubMed

    Ochoa, David; Juan, David; Valencia, Alfonso; Pazos, Florencio

    2015-07-01

    The evolution of proteins cannot be fully understood without taking into account the coevolutionary linkages entangling them. From a practical point of view, coevolution between protein families has been used as a way of detecting protein interactions and functional relationships from genomic information. The most common approach to inferring protein coevolution involves the quantification of phylogenetic tree similarity using a family of methodologies termed mirrortree. In spite of their success, a fundamental problem of these approaches is the lack of an adequate statistical framework to assess the significance of a given coevolutionary score (tree similarity). As a consequence, a number of ad hoc filters and arbitrary thresholds are required in an attempt to obtain a final set of confident coevolutionary signals. In this work, we developed a method for associating confidence estimators (P values) to the tree-similarity scores, using a null model specifically designed for the tree comparison problem. We show how this approach largely improves the quality and coverage (number of pairs that can be evaluated) of the detected coevolution in all the stages of the mirrortree workflow, independently of the starting genomic information. This not only leads to a better understanding of protein coevolution and its biological implications, but also to obtain a highly reliable and comprehensive network of predicted interactions, as well as information on the substructure of macromolecular complexes using only genomic information. The software and datasets used in this work are freely available at: http://csbg.cnb.csic.es/pMT/. pazos@cnb.csic.es Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  15. Glacial marine sedimentation: Paleoclimatic significance

    SciTech Connect

    Anderson, J.B.; Ashley, G.M.

    1991-01-01

    This publication resulted from a symposium held during the 1988 Annual Meeting of the Geological Society of America. Many, but not all, contributors to the symposium have papers in this volume. This Special Paper consists of 14 chapters and a Subject/Geographic index. Each chapter has is own list of references. The papers cover a wide range of modem climate/ ocean environments, including papers on glacial marine sediments from Antarctica, the fiords of Alaska, and sediments from the Canadian High Arctic. In addition, three papers discuss [open quote]old[close quotes] glacial marine records (i.e., pre-Tertiary), and one paper discusses the Yakataga Formation of the Gulf of Alaska which is a Miocene-to-late-Pleistocene sequence. The last chapter in the book includes a survey and summary of the evidence for the paleoclimatic significance of glacial marine sediments by the two editors, John Anderson and Gail Ashley. It is worth noting that Anderson and Domack state in the Foreword that there is a considerable variation in terminology; hence they employ a series of definitions which they urge the other authors to employ. They define and explain what they mean by [open quotes]polar ice cap,[close quotes] [open quote]polar tundra (subpolar),[close quotes] and [open quotes]temperate oceanic and boreal[close quotes] in terms of the dominant glacial and glacial marine processes. Although one might quarrel with the terminology, the broad differences between these three glaciological regimes are indeed fundamental and need to be sought in the geological record. The flavor of the volume can be judged by some of the chapter titles. Contributions on Antarctica include a paper by Anderson and other entitled [open quote]Sedimentary facies associated with Antarctica's floating ice masses[close quotes] and a companion paper by Anderson and Domack which deals with the extremely complex glacial marine facies (13 facies are delimited) in McMurdo Sound, Antarctica.

  16. Accretionary orogens: definition, character, significance

    NASA Astrophysics Data System (ADS)

    Cawood, P. A.; Kroener, A.; Windley, B. F.

    2003-04-01

    Classic models of orogens involve a Wilson cycle of ocean opening and closing with orogenesis related to continent-continent collision. Such models fail to explain the geological history of a significant number of orogenic belts throughout the world in which deformation, metamorphism and crustal growth took place in an environment of on-going plate convergence. These belts are termed accretionary orogens but have also been refereed to as non-collisional orogens, Pacific-type orogens, Turkic-type and exterior orogens. Accretionary orogens evolve in generally curvilinear belts comprising dominantly mafic to silicic igneous rocks and their sedimentary products and accumulated largely in marine settings. They are variably deformed and metamorphosed by tectono-thermal events aligned parallel to, and punctuating, facies trends. Accretionary orogens form at sites of subduction of oceanic lithosphere and consist of magmatic arcs systems along with material accreted from the downgoing plate and eroded from the upper plate. Deformational features include structures formed in extension and compressive environments during steady-state convergence (arc/backarc vs. accretionary prism) that are overprinted by short regional compressive orogenic events. Orogenesis takes place through coupling across the plate boundary with strain concentrated in zones of mechanical and thermal weakening such as the magmatic arc and back arc region. Potential driving mechanisms for coupling include accretion of buoyant lithosphere (terrane accretion), flat slab subduction, and rapid absolute upper plate motion over-riding the downgoing plate. The Circum-Pacific region provides outstanding examples of accretionary orogens. The Pacific formed during breakup of Rodinia in the Neoproterozoic and has never subsequently closed, resulting in a series of overall ocean-ward younging orogenic systems that have always faced an open ocean, yet have been the sites of repeated tectono-thermal events and

  17. Gastric siderosis: patterns and significance.

    PubMed

    Marginean, Esmeralda C; Bennick, Michael; Cyczk, Jan; Robert, Marie E; Jain, Dhanpat

    2006-04-01

    Recently, we encountered 2 cases of diffuse iron deposition in gastric antral and fundic glandular epithelium, which in 1 patient eventually led to the diagnosis of hemochromatosis. Gastric mucosal siderosis (GS) has previously been described in hemochromatosis patients, alcoholics, and in association with iron medications. However, the prevalence of various patterns of iron deposition in the gastric mucosa and their clinical significance have not been studied in detail. The 2 index cases mentioned above and 500 additional consecutive gastric biopsies examined over a period of 8 months at our institution were stained for iron by the Prussian blue method. In addition, all patients with genetic hemochromatosis diagnosed by liver biopsy in our department between 1998 and 2003 who also had gastric biopsies were identified from the surgical pathology files and included in the study (n = 3). The location of iron deposition [stromal cells (endothelium, fibroblasts, macrophages), glandular epithelium, or extracellular] was recorded and subjectively graded as 1+ to 3+ according to the severity of deposition within the mucosa. Relevant histologic changes (inflammation, presence of H. pylori, ulceration) and clinical features were reviewed. Three patterns of GS were identified: A) "nonspecific GS" with predominant iron deposition in the stromal cells including macrophages, and focally in epithelium; B) "iron-pill gastritis" with often mild gastritis and reactive gastropathy type changes, and mostly extracellular deposition with focal stromal cells and epithelial deposition; and C) predominant deposition in antral and fundic glandular epithelium. Of the 500 cases studied, a total of 18 (3.6%) cases were found to have GS. Of these 18 cases, 11 (2.2%) showed pattern A, 4 (0.8%) showed pattern B, and 3 (0.6%) showed pattern C. The GS in patterns A and B was always focal or patchy (1+ to 2+), whereas in pattern C it was generally diffuse and strong (2+ to 3+). A history of oral

  18. Astrobiological Significance of Microbial Extremophiles

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena V.; Hoover, Richard B.

    2007-01-01

    The microflora of the cryosphere of planet Earth provides the best analogs for life forms that might be found in the permafrost or polar ice caps of Mars, near the surface of the cometary nuclei, or in the liquid water beneath and the ice crusts of icy moons of Jupiter and Saturn. The importance of study alkaliphilic microorganisms for astrobiology was enhanced by the findings of abundant carbonates and carbonate globules rimmed with possibly biogenic magnetites in association with the putative microfossils in the ALH84001 meteorite. Although the ALH84001 "nanofossils" were to small and simple to be unambiguously recognized as biogenic, they stimulated Astrobiology research and studies of microbial extremophiles and biomarkers in ancient rocks and meteorites. Recent studies of CI and CM carbonaceous meteorites have resulted in the detection of the well-preserved mineralized remains of coccoidal and filamentous microorganisms in cyanobacterial mats. Energy Dispersive X-ray Analysis has shown anomalous biogenic element ratios clearly indicating they are not recent biological contaminants. This paper reviews microbial extremophiles in context of their significance to Astrobiology. The study of halophilic microorganisms was started from work with saline soils and lakes, and one of the record of good growth for Haloferax mediterranei was shown at 30 percent NaC1. Although alkali-tolerant nitrifying bacteria had previously been reported, the first described alkaliphilic microorganism was the bacterium Streptococcus faecalis. Halophilic and alkaliphilic forms are relevant to conditions that might be found in closed impact basins and craters on Mars filled with evaporite deposits. The first obligately acidophilic bacterium described was Acidithiobacillus ferrooxydans (formally Thiobacillus ferrooxidans). Later thermophilic lithotrophic acidophiles were found, and the hyperacidophilic moderately thermophilic species of the genus Picrophilus were found to grow at negative p

  19. Astrobiological Significance of Microbial Extremophiles

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena V.; Hoover, Richard B.

    2007-01-01

    The microflora of the cryosphere of planet Earth provides the best analogs for life forms that might be found in the permafrost or polar ice caps of Mars, near the surface of the cometary nuclei, or in the liquid water beneath and the ice crusts of icy moons of Jupiter and Saturn. The importance of study alkaliphilic microorganisms for astrobiology was enhanced by the findings of abundant carbonates and carbonate globules rimmed with possibly biogenic magnetites in association with the putative microfossils in the ALH84001 meteorite. Although the ALH84001 "nanofossils" were to small and simple to be unambiguously recognized as biogenic, they stimulated Astrobiology research and studies of microbial extremophiles and biomarkers in ancient rocks and meteorites. Recent studies of CI and CM carbonaceous meteorites have resulted in the detection of the well-preserved mineralized remains of coccoidal and filamentous microorganisms in cyanobacterial mats. Energy Dispersive X-ray Analysis has shown anomalous biogenic element ratios clearly indicating they are not recent biological contaminants. This paper reviews microbial extremophiles in context of their significance to Astrobiology. The study of halophilic microorganisms was started from work with saline soils and lakes, and one of the record of good growth for Haloferax mediterranei was shown at 30 percent NaC1. Although alkali-tolerant nitrifying bacteria had previously been reported, the first described alkaliphilic microorganism was the bacterium Streptococcus faecalis. Halophilic and alkaliphilic forms are relevant to conditions that might be found in closed impact basins and craters on Mars filled with evaporite deposits. The first obligately acidophilic bacterium described was Acidithiobacillus ferrooxydans (formally Thiobacillus ferrooxidans). Later thermophilic lithotrophic acidophiles were found, and the hyperacidophilic moderately thermophilic species of the genus Picrophilus were found to grow at negative p

  20. What State Tests Test.

    ERIC Educational Resources Information Center

    McGee, Glenn W.

    What the Illinois Goal Assessment Program (IGAP) test actually tests and the consequences of these tests for funding decisions were studied with a random sample of 100 school districts in the Cook County suburbs of Chicago. Eighth-grade IGAP scores for reading were obtained from the state report card, a document prepared by each school district…

  1. Test Architecture, Test Retrofit

    ERIC Educational Resources Information Center

    Fulcher, Glenn; Davidson, Fred

    2009-01-01

    Just like buildings, tests are designed and built for specific purposes, people, and uses. However, both buildings and tests grow and change over time as the needs of their users change. Sometimes, they are also both used for purposes other than those intended in the original designs. This paper explores architecture as a metaphor for language…

  2. Assessing the significant others of chronic pain patients: the psychometric properties of significant other questionnaires.

    PubMed

    Sharp, T J; Nicholas, M K

    2000-11-01

    Contemporary reviews of psychological models of chronic pain have favoured behavioural and cognitive-behavioural formulations. These have often assumed that pain behaviours are maintained by environmental reinforcers. One of the most commonly hypothesized sources of reinforcement has been patients' significant others. Further, it has often been recognized that significant others may also be affected by pain behaviours and that they may experience changes in their lifesyles and in their mood as a consequence of living with someone who has pain. Somewhat surprisingly, relatively little clinical research has been published investigating significant others and their relationships with pain patients. Among other things, one of the limiting factors has been the lack of measurement tools available for assessing the relevant variables thought to be important with regards to significant others (such as their responses to, and perceptions of, chronic pain). This study attempted to remedy this situation by developing and testing the psychometric properties of a number of questionnaires specifically designed for significant others of chronic pain patients. The questionnaires have been selected to assess both significant others' (behavioural and cognitive) responses to pain as well as the extent to which pain impacts on their lives. Although not all of the questionnaires were found to possess equally strong psychometric properties, the availability of several solid measures opens the way for more empirical analyses of significant others and their interactions with chronic pain patients.

  3. Nonpowder firearms cause significant pediatric injuries.

    PubMed

    Veenstra, Michelle; Prasad, Jai; Schaewe, Heather; Donoghue, Lydia; Langenburg, Scott

    2015-06-01

    We hypothesize that nonpowder firearms cause significant injuries in children, often requiring intervention. We have noted a difference in demographics of children presenting with injuries from nonpowder firearms compared with patients injured by powder firearms. We reviewed our institution's experience with patients with nonpowder firearm injuries to evaluate these aspects. A retrospective chart review was completed for all patients with a firearm injury from 2003 through February 2013 to a pediatric urban Level I trauma center. Patients were excluded if they were 18 years of age or older or readmitted. Demographics, injury circumstances, interventions, and outcomes were reviewed for 303 patients. The χ test and analysis of variance were completed with a statistical significance of p < 0.05. There were 57 nonpowder firearm injuries and 246 injuries from other firearms. Injuries occurred from BB, pellet, and paintball guns. Treatment included computed tomography scan in 39 patients, three bedside procedures, one angiography, and operative intervention in 25 patients. The most common injury locations were the eye (n = 37), head (n = 7), and neck (n = 6). Children injured by nonpowder firearms were less likely to be female (p = 0.04), more likely to be white (p < 0.01), and less likely to be injured in a violence-related event (p < 0.01). Nonpowder firearms can cause severe pediatric injuries requiring operative intervention and significant radiographic exposure from computed tomography scans. Prevention and education are important in decreasing this risk in the pediatric population and should be targeted to a different population than powder firearm prevention. Epidemiologic study, level V.

  4. Titanium Honeycomb Panel Testing

    NASA Technical Reports Server (NTRS)

    Richards, W. Lance; Thompson, Randolph C.

    1996-01-01

    Thermal-mechanical tests were performed on a titanium honeycomb sandwich panel to experimentally validate the hypersonic wing panel concept and compare test data with analysis. Details of the test article, test fixture development, instrumentation, and test results are presented. After extensive testing to 900 deg. F, non-destructive evaluation of the panel has not detected any significant structural degradation caused by the applied thermal-mechanical loads.

  5. Test Less - Test Right

    DTIC Science & Technology

    2011-05-17

    Large software product development & testing – Extensive Database & Business Analytics experience  Co-authored 2 books on DB2 and Business ... Intelligence  Frequent speaker at Midrange system conferences  Strategic thinking and execution with completeness of visions http://www.linkedin.com/in

  6. Clinical significance of autoantibodies in autoimmune hepatitis.

    PubMed

    Liberal, Rodrigo; Mieli-Vergani, Giorgina; Vergani, Diego

    2013-10-01

    The accurate diagnosis and classification of autoimmune hepatitis (AIH) rely upon the detection of characteristic autoantibodies. Positivity for anti-nuclear (ANA) and/or anti-smooth muscle (SMA) autoantibodies defines AIH type 1 (AIH-1), whereas anti-liver kidney microsomal type 1 (anti-LKM1) and/or anti-liver cytosol type 1 (anti-LC1) define AIH type 2 (AIH-2). ANA and SMA, and less commonly anti-LKM1, have also been detected in de-novo autoimmune hepatitis developing after liver transplantation, a condition that may affect patients transplanted for non-autoimmune liver disease. The diagnostic autoantibodies associated with AIH-1 are also detected in the paediatric AIH/sclerosing cholangitis overlap syndrome, referred to as autoimmune sclerosing cholangitis (ASC). ASC, like adult primary sclerosing cholangitis, is often associated with atypical perinuclear anti-neutrophil cytoplasmic autoantibodies (p-ANCA), although p-ANCA are also detected in other autoimmune liver diseases. These associations highlight the necessity for simple and prompt diagnostic autoantibody testing, and the requirement for the accurate interpretation of the results of the tests in the clinical context. Fine-mapping of antigenic autoantibody targets has facilitated the development of rapid molecular assays that have the potential to revolutionise the field if properly standardised and when used in combination with classical immunofluorescence. Despite their diagnostic significance, the pathogenic role of the various autoantibodies and the mechanisms by which they can potentially inflict damage onto the liver cell remain a topic for further research.

  7. Posttonsillectomy taste distortion: a significant complication.

    PubMed

    Goins, Michael R; Pitovski, Dimitri Z

    2004-07-01

    Tonsillectomy is among the most commonly performed procedures. As with any surgery, head and neck surgeons must be aware of possible complications and their potential affects. At our smell and taste center, we have been referred several patients in a 6-month period with the complaint of taste distortion after tonsillectomy. We report in this article a patient that complains of taste distortion after a right tonsillectomy for unilateral tonsillar hypertrophy. A prospective study documenting taste distortion after tonsillectomy using clinical, subjective, and objective evaluation. The clinical course of a patient with taste distortion after a tonsillectomy is described. The gustatory function was investigated by conducting electrogustometry and spatial taste testing. Threshold measurements were determined at three left- and three right-side tongue regions: 1) the tongue tip region (innervated by the chorda tympani branch of the facial nerve), 2) the lateral margin of the tongue (anterior to the foliate papillae), and 3) the posterior tongue region (innervated by the lingual branch of the glossopharyngeal nerve). After a complete clinical evaluation and taste testing, it was found that the patient suffered an injury to the right lingual branch of the glossopharyngeal nerve. The close anatomic relationship between the palatine tonsil and lingual branch of the glossopharyngeal nerve makes the nerve vulnerable during tonsillectomy. This injury has caused the patient to suffer ageusia to the right posterior one third of the tongue, compensated by a contralateral phantogeusia (phantom taste) with clinical dysgeusia. The phantogeusia was abolished by application of anesthetic to the area where the phantom was perceived. We propose that the phantogeusia is the result of release-of-inhibition in the contralateral glossopharyngeal nerve. Taste distortion (including, phantogeusia and dysgeusia) after tonsillectomy is rarely reported as a complication but has a significant

  8. Test plan :

    SciTech Connect

    Dwyer, Stephen F.

    2013-05-01

    This test plan is a document that provides a systematic approach to the planned testing of rooftop structures to determine their actual load carrying capacity. This document identifies typical tests to be performed, the responsible parties for testing, the general feature of the tests, the testing approach, test deliverables, testing schedule, monitoring requirements, and environmental and safety compliance.

  9. Assessing statistical significance in causal graphs

    PubMed Central

    2012-01-01

    Background Causal graphs are an increasingly popular tool for the analysis of biological datasets. In particular, signed causal graphs--directed graphs whose edges additionally have a sign denoting upregulation or downregulation--can be used to model regulatory networks within a cell. Such models allow prediction of downstream effects of regulation of biological entities; conversely, they also enable inference of causative agents behind observed expression changes. However, due to their complex nature, signed causal graph models present special challenges with respect to assessing statistical significance. In this paper we frame and solve two fundamental computational problems that arise in practice when computing appropriate null distributions for hypothesis testing. Results First, we show how to compute a p-value for agreement between observed and model-predicted classifications of gene transcripts as upregulated, downregulated, or neither. Specifically, how likely are the classifications to agree to the same extent under the null distribution of the observed classification being randomized? This problem, which we call "Ternary Dot Product Distribution" owing to its mathematical form, can be viewed as a generalization of Fisher's exact test to ternary variables. We present two computationally efficient algorithms for computing the Ternary Dot Product Distribution and investigate its combinatorial structure analytically and numerically to establish computational complexity bounds. Second, we develop an algorithm for efficiently performing random sampling of causal graphs. This enables p-value computation under a different, equally important null distribution obtained by randomizing the graph topology but keeping fixed its basic structure: connectedness and the positive and negative in- and out-degrees of each vertex. We provide an algorithm for sampling a graph from this distribution uniformly at random. We also highlight theoretical challenges unique to signed

  10. HIV Testing

    MedlinePlus

    ... antibody tests, combination or fourth-generation tests, and nucleic acid tests (NAT). HIV tests may be performed on ... retested 3 months after your possible exposure. A nucleic acid test (NAT) looks for HIV in the blood. ...

  11. Pinworm test

    MedlinePlus

    Oxyuriasis test; Enterobiasis test; Tape test ... diagnose this infection is to do a tape test. The best time to do this is in ... lay their eggs at night. Steps for the test are: Firmly press the sticky side of a ...

  12. Liquid Rocket Engine Testing

    NASA Technical Reports Server (NTRS)

    Rahman, Shamim

    2005-01-01

    Comprehensive Liquid Rocket Engine testing is essential to risk reduction for Space Flight. Test capability represents significant national investments in expertise and infrastructure. Historical experience underpins current test capabilities. Test facilities continually seek proactive alignment with national space development goals and objectives including government and commercial sectors.

  13. Quantifying the Clinical Significance of Cannabis Withdrawal

    PubMed Central

    Allsop, David J.; Copeland, Jan; Norberg, Melissa M.; Fu, Shanlin; Molnar, Anna; Lewis, John; Budney, Alan J.

    2012-01-01

    Background and Aims Questions over the clinical significance of cannabis withdrawal have hindered its inclusion as a discrete cannabis induced psychiatric condition in the Diagnostic and Statistical Manual of Mental Disorders (DSM IV). This study aims to quantify functional impairment to normal daily activities from cannabis withdrawal, and looks at the factors predicting functional impairment. In addition the study tests the influence of functional impairment from cannabis withdrawal on cannabis use during and after an abstinence attempt. Methods and Results A volunteer sample of 49 non-treatment seeking cannabis users who met DSM-IV criteria for dependence provided daily withdrawal-related functional impairment scores during a one-week baseline phase and two weeks of monitored abstinence from cannabis with a one month follow up. Functional impairment from withdrawal symptoms was strongly associated with symptom severity (p = 0.0001). Participants with more severe cannabis dependence before the abstinence attempt reported greater functional impairment from cannabis withdrawal (p = 0.03). Relapse to cannabis use during the abstinence period was associated with greater functional impairment from a subset of withdrawal symptoms in high dependence users. Higher levels of functional impairment during the abstinence attempt predicted higher levels of cannabis use at one month follow up (p = 0.001). Conclusions Cannabis withdrawal is clinically significant because it is associated with functional impairment to normal daily activities, as well as relapse to cannabis use. Sample size in the relapse group was small and the use of a non-treatment seeking population requires findings to be replicated in clinical samples. Tailoring treatments to target withdrawal symptoms contributing to functional impairment during a quit attempt may improve treatment outcomes. PMID:23049760

  14. The measure and significance of Bateman's principles.

    PubMed

    Collet, Julie M; Dean, Rebecca F; Worley, Kirsty; Richardson, David S; Pizzari, Tommaso

    2014-05-07

    Bateman's principles explain sex roles and sexual dimorphism through sex-specific variance in mating success, reproductive success and their relationships within sexes (Bateman gradients). Empirical tests of these principles, however, have come under intense scrutiny. Here, we experimentally show that in replicate groups of red junglefowl, Gallus gallus, mating and reproductive successes were more variable in males than in females, resulting in a steeper male Bateman gradient, consistent with Bateman's principles. However, we use novel quantitative techniques to reveal that current methods typically overestimate Bateman's principles because they (i) infer mating success indirectly from offspring parentage, and thus miss matings that fail to result in fertilization, and (ii) measure Bateman gradients through the univariate regression of reproductive over mating success, without considering the substantial influence of other components of male reproductive success, namely female fecundity and paternity share. We also find a significant female Bateman gradient but show that this likely emerges as spurious consequences of male preference for fecund females, emphasizing the need for experimental approaches to establish the causal relationship between reproductive and mating success. While providing qualitative support for Bateman's principles, our study demonstrates how current approaches can generate a misleading view of sex differences and roles.

  15. Exercise oscillatory ventilation: Mechanisms and prognostic significance

    PubMed Central

    Dhakal, Bishnu P; Lewis, Gregory D

    2016-01-01

    Alteration in breathing patterns characterized by cyclic variation of ventilation during rest and during exercise has been recognized in patients with advanced heart failure (HF) for nearly two centuries. Periodic breathing (PB) during exercise is known as exercise oscillatory ventilation (EOV) and is characterized by the periods of hyperpnea and hypopnea without interposed apnea. EOV is a non-invasive parameter detected during submaximal cardiopulmonary exercise testing. Presence of EOV during exercise in HF patients indicates significant impairment in resting and exercise hemodynamic parameters. EOV is also an independent risk factor for poor prognosis in HF patients both with reduced and preserved ejection fraction irrespective of other gas exchange variables. Circulatory delay, increased chemosensitivity, pulmonary congestion and increased ergoreflex signaling have been proposed as the mechanisms underlying the generation of EOV in HF patients. There is no proven treatment of EOV but its reversal has been noted with phosphodiesterase inhibitors, exercise training and acetazolamide in relatively small studies. In this review, we discuss the mechanistic basis of PB during exercise and the clinical implications of recognizing PB patterns in patients with HF. PMID:27022457

  16. Statistical Significance of Clustering using Soft Thresholding

    PubMed Central

    Huang, Hanwen; Liu, Yufeng; Yuan, Ming; Marron, J. S.

    2015-01-01

    Clustering methods have led to a number of important discoveries in bioinformatics and beyond. A major challenge in their use is determining which clusters represent important underlying structure, as opposed to spurious sampling artifacts. This challenge is especially serious, and very few methods are available, when the data are very high in dimension. Statistical Significance of Clustering (SigClust) is a recently developed cluster evaluation tool for high dimensional low sample size data. An important component of the SigClust approach is the very definition of a single cluster as a subset of data sampled from a multivariate Gaussian distribution. The implementation of SigClust requires the estimation of the eigenvalues of the covariance matrix for the null multivariate Gaussian distribution. We show that the original eigenvalue estimation can lead to a test that suffers from severe inflation of type-I error, in the important case where there are a few very large eigenvalues. This paper addresses this critical challenge using a novel likelihood based soft thresholding approach to estimate these eigenvalues, which leads to a much improved SigClust. Major improvements in SigClust performance are shown by both mathematical analysis, based on the new notion of Theoretical Cluster Index, and extensive simulation studies. Applications to some cancer genomic data further demonstrate the usefulness of these improvements. PMID:26755893

  17. Pharmacogenomic Testing

    MedlinePlus

    ... Primary care providers Specialists Getting covered Research Basic science research Research in people ... screening Diagnostic testing Direct-to-consumer genetic testing Newborn screening Pharmacogenomic testing ...

  18. Predictive Testing

    MedlinePlus

    ... Primary care providers Specialists Getting covered Research Basic science research Research in people ... screening Diagnostic testing Direct-to-consumer genetic testing Newborn screening Pharmacogenomic testing ...

  19. NGST Optical Testing

    NASA Technical Reports Server (NTRS)

    Keski-Kuha, Ritva

    1999-01-01

    An Integrated Product Team (IPT) was formed to develop a detailed optical test methodology for testing of the Next Generation Space Telescope (NGST) mirrors and the optical system on the ground. Optical testing is a significant cost driver therefore the testing has to be planned in detailed fashion early. This paper will discuss the preliminary metrology test plan at the mirror component and telescope system level. Instrumentation, facilities and schedule will also be addressed.

  20. Trypsinogen Test

    MedlinePlus

    ... name: Immunoreactive Trypsinogen Related tests: Chymotrypsin ; Sweat Test ; CF Gene Mutation Testing All content on Lab Tests ... of some newborn screening programs to screen for cystic fibrosis (CF) . It may be used in conjunction with ...

  1. Pregnancy Tests

    MedlinePlus

    ... Us Home A-Z Health Topics Pregnancy tests Pregnancy tests > A-Z Health Topics Pregnancy test fact ... To receive Publications email updates Enter email Submit Pregnancy tests If you think you may be pregnant , ...

  2. Ham test

    MedlinePlus

    Acid hemolysin test; Paroxysmal nocturnal hemoglobinuria - Ham test; PNH - Ham test ... BJ. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures . 6th ed. Philadelphia, PA: Elsevier ...

  3. TAXONOMICALLY SIGNIFICANT COLOR REACTIONS OF BREVIBACTERIUM LINENS

    PubMed Central

    Grecz, Nicholas; Dack, Gail M.

    1961-01-01

    Grecz, Nicholas (University of Chicago, Chicago, Ill.), and Gail M. Dack. Taxonomically significant color reactions of Brevibacterium linens. J. Bacteriol. 82:241–246. 1961.—Brevibacterium linens was observed to give characteristic color reactions with certain bases and acids. An intensive carmine-red color appeared immediately after addition of a drop of 5 n sodium hydroxide, 5 n potassium hydroxide, and saturated barium hydroxide. A light carmine-red was given by lithium hydroxide, and a light orange-red with a milky suspension of calcium hydroxide. No discernible color change was given with weak bases such as ammonium hydroxide, aniline, and pyridine. A characteristic salmon-pink color was produced when B. linens was rubbed with a glass rod in a drop of glacial acetic acid or filter paper; a brick-red color was produced with aniline under these conditions. With syrupy phosphoric acid a green color appeared within 3 to 4 min which turned blue after approximately 3 hr. The blue color was stable for several days. On the basis of these color reactions, B. linens could be distinguished from other microorganisms possessing yellow-orange pigmentation, i.e., Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus flavus, Micrococcus citreus, Mycobacterium phlei, Sarcina lutea. Therefore, these color changes may be used for the identification of B. linens. Original isolates of B. linens from cheese were tested by these spot reactions and all presumptive identifications could be subsequently confirmed by conventional methods. Blue and green colors appeared in all yellow-orange chromogens treated with sulfuric, perchloric, and hydrochloric acids and hence these colors were not specific for B. linens. PMID:13708147

  4. Taxonomically significant color reactions of Brevibacterium linens.

    PubMed

    GRECZ, N; DACK, G M

    1961-08-01

    Grecz, Nicholas (University of Chicago, Chicago, Ill.), and Gail M. Dack. Taxonomically significant color reactions of Brevibacterium linens. J. Bacteriol. 82:241-246. 1961.-Brevibacterium linens was observed to give characteristic color reactions with certain bases and acids. An intensive carmine-red color appeared immediately after addition of a drop of 5 n sodium hydroxide, 5 n potassium hydroxide, and saturated barium hydroxide. A light carmine-red was given by lithium hydroxide, and a light orange-red with a milky suspension of calcium hydroxide. No discernible color change was given with weak bases such as ammonium hydroxide, aniline, and pyridine.A characteristic salmon-pink color was produced when B. linens was rubbed with a glass rod in a drop of glacial acetic acid or filter paper; a brick-red color was produced with aniline under these conditions. With syrupy phosphoric acid a green color appeared within 3 to 4 min which turned blue after approximately 3 hr. The blue color was stable for several days. On the basis of these color reactions, B. linens could be distinguished from other microorganisms possessing yellow-orange pigmentation, i.e., Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus flavus, Micrococcus citreus, Mycobacterium phlei, Sarcina lutea. Therefore, these color changes may be used for the identification of B. linens. Original isolates of B. linens from cheese were tested by these spot reactions and all presumptive identifications could be subsequently confirmed by conventional methods. Blue and green colors appeared in all yellow-orange chromogens treated with sulfuric, perchloric, and hydrochloric acids and hence these colors were not specific for B. linens.

  5. Physiological Significance of Network Organization in Fungi

    PubMed Central

    Simonin, Anna; Palma-Guerrero, Javier; Fricker, Mark

    2012-01-01

    The evolution of multicellularity has occurred in diverse lineages and in multiple ways among eukaryotic species. For plants and fungi, multicellular forms are derived from ancestors that failed to separate following cell division, thus retaining cytoplasmic continuity between the daughter cells. In networked organisms, such as filamentous fungi, cytoplasmic continuity facilitates the long-distance transport of resources without the elaboration of a separate vascular system. Nutrient translocation in fungi is essential for nutrient cycling in ecosystems, mycorrhizal symbioses, virulence, and substrate utilization. It has been proposed that an interconnected mycelial network influences resource translocation, but the theory has not been empirically tested. Here we show, by using mutants that disrupt network formation in Neurospora crassa (Δso mutant, no fusion; ΔPrm-1 mutant, ∼50% fusion), that the translocation of labeled nutrients is adversely affected in homogeneous environments and is even more severely impacted in heterogeneous environments. We also show that the ability to share resources and genetic exchange between colonies (via hyphal fusion) is very limited in mature colonies, in contrast to in young colonies and germlings that readily share nutrients and genetic resources. The differences in genetic/resource sharing between young and mature colonies were associated with variations in colony architecture (hyphal differentiation/diameters, branching patterns, and angles). Thus, the ability to share resources and genetic material between colonies is developmentally regulated and is a function of the age of a colony. This study highlights the necessity of hyphal fusion for efficient nutrient translocation within an N. crassa colony but also shows that established N. crassa colonies do not share resources in a significant manner. PMID:22962278

  6. Clinical colour vision tests.

    PubMed

    Dain, Stephen J

    2004-07-01

    The structure and function of the available and significant clinical colour vision tests are reviewed in the light of the needs in the clinical examination of congenital and acquired colour vision deficiencies. The tests are grouped and described as pseudo-isochromatic plates, arrangement tests, matching tests and vocational tests. The colorimetric constructions of the test types are described and the efficiency of their performance and usefulness discussed. Recommendations are made for basic and extended test batteries, when examining of congenital and acquired colour vision deficiencies in the consulting room.

  7. FINANCIAL MANAGEMENT SERVICE: Significant Weaknesses in Computer Controls Continue

    DTIC Science & Technology

    2002-01-01

    FISCAM ).5 During the interim years, we focus our testing on the FISCAM areas that we have determined to be at greater risk for computer control...general control areas defined in FISCAM at multiple FMS data centers. Page 6 GAO-02-317 FMS Computer Controls Table 1: Areas Where Significant General...in the FISCAM . During the interim years, we focus our testing on the FISCAM areas that we have determined to be at greater risk for computer control

  8. 48 CFR 2110.7003 - Significant events.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Significant events. 2110..., AND OTHER PURCHASE DESCRIPTIONS Contract Specifications 2110.7003 Significant events. The contractor is required to inform the contracting officer of all significant events....

  9. 48 CFR 2110.7003 - Significant events.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Significant events. 2110..., AND OTHER PURCHASE DESCRIPTIONS Contract Specifications 2110.7003 Significant events. The contractor is required to inform the contracting officer of all significant events....

  10. 48 CFR 2110.7003 - Significant events.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Significant events. 2110..., AND OTHER PURCHASE DESCRIPTIONS Contract Specifications 2110.7003 Significant events. The contractor is required to inform the contracting officer of all significant events....

  11. 48 CFR 2110.7003 - Significant events.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Significant events. 2110..., AND OTHER PURCHASE DESCRIPTIONS Contract Specifications 2110.7003 Significant events. The contractor is required to inform the contracting officer of all significant events....

  12. 48 CFR 2110.7003 - Significant events.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Significant events. 2110..., AND OTHER PURCHASE DESCRIPTIONS Contract Specifications 2110.7003 Significant events. The contractor is required to inform the contracting officer of all significant events....

  13. 40 CFR 1508.27 - Significantly.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Significantly. 1508.27 Section 1508.27 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY TERMINOLOGY AND INDEX § 1508.27 Significantly. Significantly as used in NEPA requires considerations of both context and intensity: (a) Context. This...

  14. Creating Significant Learning Experiences across Disciplines

    ERIC Educational Resources Information Center

    Levine, Laura E.; Fallahi, Carolyn R.; Nicoll-Senft, Joan M.; Tessier, Jack T.; Watson, Cheryl L.; Wood, Rebecca M.

    2008-01-01

    The purpose of this study was to use Fink's (2003) taxonomy of significant learning to redesign courses and assess student learning. Significant improvements were found across the semester for students in the six courses, but there were differences in which taxa showed improvement in each course. The meta-analysis showed significant, positive…

  15. 23 CFR 630.1010 - Significant projects.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Significant projects. 630.1010 Section 630.1010 Highways... PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1010 Significant projects. (a) A significant project is one that, alone or in combination with other concurrent projects nearby is anticipated to cause...

  16. 23 CFR 630.1010 - Significant projects.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Significant projects. 630.1010 Section 630.1010 Highways... PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1010 Significant projects. (a) A significant project is one that, alone or in combination with other concurrent projects nearby is anticipated to cause...

  17. 23 CFR 630.1010 - Significant projects.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Significant projects. 630.1010 Section 630.1010 Highways... PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1010 Significant projects. (a) A significant project is one that, alone or in combination with other concurrent projects nearby is anticipated to cause...

  18. 23 CFR 630.1010 - Significant projects.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Significant projects. 630.1010 Section 630.1010 Highways... PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1010 Significant projects. (a) A significant project is one that, alone or in combination with other concurrent projects nearby is anticipated to cause...

  19. 23 CFR 630.1010 - Significant projects.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Significant projects. 630.1010 Section 630.1010 Highways... PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1010 Significant projects. (a) A significant project is one that, alone or in combination with other concurrent projects nearby is anticipated to cause...

  20. Creating Significant Learning Experiences across Disciplines

    ERIC Educational Resources Information Center

    Levine, Laura E.; Fallahi, Carolyn R.; Nicoll-Senft, Joan M.; Tessier, Jack T.; Watson, Cheryl L.; Wood, Rebecca M.

    2008-01-01

    The purpose of this study was to use Fink's (2003) taxonomy of significant learning to redesign courses and assess student learning. Significant improvements were found across the semester for students in the six courses, but there were differences in which taxa showed improvement in each course. The meta-analysis showed significant, positive…

  1. On Statistical Testing.

    ERIC Educational Resources Information Center

    Huberty, Carl J.

    An approach to statistical testing, which combines Neyman-Pearson hypothesis testing and Fisher significance testing, is recommended. The use of P-values in this approach is discussed in some detail. The author also discusses some problems which are often found in introductory statistics textbooks. The problems involve the definitions of…

  2. Collaborative Testing

    PubMed Central

    Nafziger, Rita; Meseke, Jamie K.; Meseke, Christopher A.

    2011-01-01

    Purpose: With increased focus on student preparation for high-stakes licensure exams, there is more interest in alternate forms of content delivery and assessment. This interest has focused on factors within the learning environment that may impact student's course performance and program progress. In this project, the impact of the method of group determination (random assignment vs. student selection) on student performance in a neuroanatomy course within a collaborative testing environment is examined. Methods: The course performance of two cohorts (cohort one: randomized grouping = 80; cohort two: student-selected grouping = 82) were compared. All students completed weekly quizzes within collaborative groups, while completing unit exams individually. The mean sum of both the quiz scores and examination scores were compared. Results: While the two groups differed (Wilks' lambda = 0.211; F = 53.541; df = 10,143; p < .05), no pattern was evident among the assessments (ie, one group did not differ significantly on all quizzes or examinations). In overall quiz performance, the randomized groupings scored significantly higher than the student-selected groups (F = 112.252; df = 1152; p < .05) while no difference was noted relative to overall exam scores (F = 2.672; df = 1152; p > .05). Conclusions: While the collaborative testing paradigm has been shown to be a valuable learning tool, no differences are apparent in the course performance between students in randomly assigned groups compared to those in student-selected groups. The very nature of random groups may have encouraged students to be proficient in all of the material, whereas students who were allowed to choose their groups may have divided the material among themselves and not become individually proficient in all concepts. PMID:21677868

  3. Laboratory Tests

    MedlinePlus

    Laboratory tests check a sample of your blood, urine, or body tissues. A technician or your doctor ... compare your results to results from previous tests. Laboratory tests are often part of a routine checkup ...

  4. Susceptibility Testing

    MedlinePlus

    ... Testing ; MRSA ; Fungal Tests ; Sputum Culture ; Stool Culture ; Gram Stain ; Body Fluid Analysis ; Pleural Fluid Analysis ; Pericardial ... to Get Tested? As follow up to a positive bacterial or fungal culture ; when you have an ...

  5. Lipase Test

    MedlinePlus

    ... known as: LPS Formal name: Lipase Related tests: Amylase , Trypsin , Trypsinogen At a Glance Test Sample The ... lipase is most often used, along with an amylase test , to help diagnose and monitor acute pancreatitis . ...

  6. Hardness testing

    SciTech Connect

    Not Available

    1987-01-01

    This technical manual is a handbook dealing with all aspects of hardness testing. Every hardness testing method is fully covered, from Rockwell to ultrasonic hardness testing. Specific hardness testing problems are also discussed, and methods are offered for many applications. One chapter examines how to select the correct hardness testing method. A directory of manufacturers, distributors and suppliers of hardness testing equipment and supplies in the United States and Canada is also included. The book consist of eight chapters and an appendix. It discusses common concepts of hardness, and the theories and methods of hardness testing. Coverage includes specific hardness testing methods - Brinell, Rockwell, Vickers, and microhardness testing; and other hardness testing methods, such as scleroscope, ultrasonic, scratch and file testing, and hardness evaluation by eddy current testing.

  7. Test Madness

    ERIC Educational Resources Information Center

    Hedrick, Wanda B., Ed.

    2007-01-01

    There's accountability and then there's the testing craze an iatrogenic practice that undermines real learning. Hedrick documents the negative effects of testing, giving teachers another weapon in their arsenal against mindless preparation for high-stakes tests.

  8. Thyroid Tests

    MedlinePlus

    ... the thyroid, a computerized tomography (CT) scan, or nuclear medicine tests, to diagnose and find the cause ... is having the scan for other health problems. Nuclear medicine tests. Nuclear medicine tests of the thyroid ...

  9. Test Madness

    ERIC Educational Resources Information Center

    Hedrick, Wanda B., Ed.

    2007-01-01

    There's accountability and then there's the testing craze an iatrogenic practice that undermines real learning. Hedrick documents the negative effects of testing, giving teachers another weapon in their arsenal against mindless preparation for high-stakes tests.

  10. Stool Tests

    MedlinePlus

    ... For Kids For Parents MORE ON THIS TOPIC E. Coli Giardiasis Yersiniosis Stool Test: Bacteria Culture Stool Test: ... Stool Test: Ova and Parasites (O&P) Diarrhea E. Coli Contact Us Print Resources Send to a Friend ...

  11. Understanding Magnetic Anomalies and Their Significance.

    ERIC Educational Resources Information Center

    Shea, James H.

    1988-01-01

    Describes a laboratory exercise testing the Vine-Matthews-Morley hypothesis of plate tectonics. Includes 14 questions with explanations using graphs and charts. Provides a historical account of the current plate tectonic and magnetic anomaly theory. (MVL)

  12. Understanding Magnetic Anomalies and Their Significance.

    ERIC Educational Resources Information Center

    Shea, James H.

    1988-01-01

    Describes a laboratory exercise testing the Vine-Matthews-Morley hypothesis of plate tectonics. Includes 14 questions with explanations using graphs and charts. Provides a historical account of the current plate tectonic and magnetic anomaly theory. (MVL)

  13. Historic tests

    NASA Image and Video Library

    2012-08-16

    Two large-engine tests were conducted simultaneously for the first time at Stennis Space Center on Aug. 16. A plume on the left indicates a test on the facility's E-1 Test Stand. On the right, a finger of fire indicates a test under way on the A-1 Test Stand. In another first, both tests were conducted by female engineers. The image was taken from atop the facility's A-2 Test Stand, offering a panoramic view that includes the new A-3 Test Stand under construction to the left.

  14. Intraoperative medications associated with hemodynamically significant anaphylaxis.

    PubMed

    Freundlich, Robert E; Duggal, Neal M; Housey, Michelle; Tremper, Tyler T; Engoren, Milo C; Kheterpal, Sachin

    2016-12-01

    To facilitate the identification of drugs and patient factors associated with hemodynamically significant anaphylaxis. Using an existing database containing complete perioperative records, instances of hemodynamically significant anaphylaxis were identified using a physiologic and treatment-based screening algorithm. All cases were manually reviewed by 2 clinicians, with a third adjudicating disagreements, and confirmed cases were matched 3:1 with control cases. Intraoperative medications given in instances of hemodynamically significant anaphylaxis and patient risk factors were compared with control cases. University of Michigan Hospital, a large, tertiary care hospital. All adult patients undergoing surgery between January 1, 2004, and January 5, 2015. None. Incidence of hemodynamically significant anaphylaxis during anesthesia. Patient risk factors and intraoperative medications associated with hemodynamically significant anaphylaxis. Hemodynamically significant anaphylaxis occurred in 55 of 461 986 cases (1 in 8400). Hemodynamically significant anaphylaxis occurred in 52 patients, with 1 patient experiencing 3 instances and another patient 2 instances. Only 1 drug was associated with an increased risk of hemodynamically significant anaphylaxis: protamine (odds ratio, 11.78; 95% confidence interval, 1.40-99.26; P=.0233). No category of drugs was associated with increased risk. Of patient risk factors, only personal history of anaphylaxis was associated with an increased risk (odds ratio, 77.1; 95% confidence interval, 10.46-567.69; P=<.0001). Postoperative follow-up and evaluation of patients were low at our institution. A serum tryptase level was sent in only 49% of cases, and 41% of levels were positive, an overall positive rate of 20% of cases. Following instances of hemodynamically significant anaphylaxis, only 29% of patients were seen and evaluated by an allergist at our institution. Hemodynamically significant anaphylaxis is a rare complication of

  15. Significant Reading Experiences of Superior English Students.

    ERIC Educational Resources Information Center

    Whitman, Robert S.

    1964-01-01

    Superior high school students (975 finalists in the NCTE Achievement Awards Program) were surveyed to find what one book was most significant to each of them in their high school experiences, and the reason for the significance. In response to questionnaires, the students cited 416 different titles, 72% of which were novels. The top 10 books were…

  16. Significance of selected lineaments in Alabama

    NASA Technical Reports Server (NTRS)

    Drahovzal, J. A.; Neathery, T. L.; Wielchowsky, C. C.

    1974-01-01

    Four lineaments in the Alabama Appalachians that appear on ERTS-1 imagery have been geologically analysed. Two of the lineaments appear to have regional geologic significance, showing relationships to structural and stratigraphic frameworks, water and mineral resources, geophysical anomalies, and seismicity. The other two lineaments are of local geologic significance, but, nevertheless, have important environmental implications.

  17. 32 CFR 1280.3 - Significant changes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Significant changes. 1280.3 Section 1280.3 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS INVESTIGATING AND PROCESSING CERTAIN NONCONTRACTUAL CLAIMS AND REPORTING RELATED LITIGATION § 1280.3 Significant...

  18. 32 CFR 1280.3 - Significant changes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Significant changes. 1280.3 Section 1280.3 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS INVESTIGATING AND PROCESSING CERTAIN NONCONTRACTUAL CLAIMS AND REPORTING RELATED LITIGATION § 1280.3 Significant...

  19. The Vernier Caliper and Significant Figures.

    ERIC Educational Resources Information Center

    Oberhofer, E. S.

    1985-01-01

    Misconceptions occur because the caliper is often read with the same significant figures as a meter stick; however, the precision of the vernier caliper is greater than the precision of a meter stick. Clarification of scale reading, precision of both tools, and significant figures are discussed. (JN)

  20. Measuring Clinical Significance in Rehabilitation Research

    ERIC Educational Resources Information Center

    Johnson, Erica K.; Dow, Christian; Lynch, Ruth T.; Hermann, Bruce P.

    2006-01-01

    Measurement of clinically significant change is critical for rehabilitation research because it can enhance the credibility of rehabilitation efforts and guide evidence-based practices. The practical appeal of clinically significant change is that it can bridge research and clinical practice by focusing on individual rather than group differences.…

  1. 32 CFR 651.39 - Significance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... for evaluating regional economic impacts under NEPA. This system is mandated, as Army policy, for use... proposed action may or will result in significant impacts to the environment, an EIS is prepared to provide more comprehensive analyses and conclusions about the impacts. Significant impacts of...

  2. 40 CFR 1508.27 - Significantly.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... areas. (4) The degree to which the effects on the quality of the human environment are likely to be highly controversial. (5) The degree to which the possible effects on the human environment are highly... significant impact on the environment. Significance cannot be avoided by terming an action temporary or...

  3. 32 CFR 1280.3 - Significant changes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 6 2013-07-01 2013-07-01 false Significant changes. 1280.3 Section 1280.3 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS INVESTIGATING AND PROCESSING CERTAIN NONCONTRACTUAL CLAIMS AND REPORTING RELATED LITIGATION § 1280.3 Significant...

  4. 32 CFR 1280.3 - Significant changes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Significant changes. 1280.3 Section 1280.3 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS INVESTIGATING AND PROCESSING CERTAIN NONCONTRACTUAL CLAIMS AND REPORTING RELATED LITIGATION § 1280.3 Significant...

  5. 32 CFR 1280.3 - Significant changes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Significant changes. 1280.3 Section 1280.3 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS INVESTIGATING AND PROCESSING CERTAIN NONCONTRACTUAL CLAIMS AND REPORTING RELATED LITIGATION § 1280.3 Significant...

  6. 40 CFR 1508.27 - Significantly.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., significance would usually depend upon the effects in the locale rather than in the world as a whole. Both short- and long-term effects are relevant. (b) Intensity. This refers to the severity of impact... both beneficial and adverse. A significant effect may exist even if the Federal agency believes that...

  7. 40 CFR 1508.27 - Significantly.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., significance would usually depend upon the effects in the locale rather than in the world as a whole. Both short- and long-term effects are relevant. (b) Intensity. This refers to the severity of impact... both beneficial and adverse. A significant effect may exist even if the Federal agency believes that...

  8. Evolution of the Significant Figure Rules

    ERIC Educational Resources Information Center

    Carter, Ashley R.

    2013-01-01

    Today, almost all introductory physics textbooks include standardized "rules" on how to find the number of significant figures in a calculated value. And yet, 30 years ago these rules were almost nonexistent. Why have we increased the role of significant figures in introductory classes, and should we continue this trend? A look back at…

  9. 7 CFR 3015.93 - Significant developments.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Significant developments. 3015.93 Section 3015.93... § 3015.93 Significant developments. Events may occur between the scheduled performance reporting dates... assistance needed to resolve the situation. (b) Favorable developments which enable meeting time schedules...

  10. 7 CFR 3015.93 - Significant developments.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Significant developments. 3015.93 Section 3015.93... § 3015.93 Significant developments. Events may occur between the scheduled performance reporting dates... assistance needed to resolve the situation. (b) Favorable developments which enable meeting time schedules...

  11. 7 CFR 3015.93 - Significant developments.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Significant developments. 3015.93 Section 3015.93... § 3015.93 Significant developments. Events may occur between the scheduled performance reporting dates... assistance needed to resolve the situation. (b) Favorable developments which enable meeting time schedules...

  12. 7 CFR 3015.93 - Significant developments.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Significant developments. 3015.93 Section 3015.93... § 3015.93 Significant developments. Events may occur between the scheduled performance reporting dates... assistance needed to resolve the situation. (b) Favorable developments which enable meeting time schedules...

  13. 7 CFR 3015.93 - Significant developments.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Significant developments. 3015.93 Section 3015.93... § 3015.93 Significant developments. Events may occur between the scheduled performance reporting dates... assistance needed to resolve the situation. (b) Favorable developments which enable meeting time schedules...

  14. 32 CFR 651.39 - Significance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 4 2012-07-01 2011-07-01 true Significance. 651.39 Section 651.39 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Environmental Assessment § 651.39 Significance. (a) If...

  15. 32 CFR 651.39 - Significance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 4 2014-07-01 2013-07-01 true Significance. 651.39 Section 651.39 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Environmental Assessment § 651.39 Significance. (a) If...

  16. 32 CFR 651.39 - Significance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 4 2013-07-01 2013-07-01 false Significance. 651.39 Section 651.39 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Environmental Assessment § 651.39 Significance. (a) If...

  17. 45 CFR 1351.1 - Significant terms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 4 2012-10-01 2012-10-01 false Significant terms. 1351.1 Section 1351.1 Public... SERVICES BUREAU RUNAWAY AND HOMELESS YOUTH PROGRAM Definition of Terms § 1351.1 Significant terms. For the... herself from home or place of legal residence without the permission of his or her family. (l) Short-term...

  18. Earth observations and photography experiment: Summary of significant results

    NASA Technical Reports Server (NTRS)

    El-Baz, F.

    1978-01-01

    Observation and photographic data from the Apollo Soyuz Test Project are analyzed. The discussion is structured according to the fields of investigation including: geology, desert studies, oceanography, hydrology, and meteorology. The data were obtained by: (1) visual observations of selected Earth features, (2) hand-held camera photography to document observations, and (3) stereo mapping photography of areas of significant scientific interest.

  19. Spectroscopic probes of vibrationally excited molecules at chemically significant energies

    SciTech Connect

    Rizzo, T.R.

    1993-12-01

    This project involves the application of multiple-resonance spectroscopic techniques for investigating energy transfer and dissociation dynamics of highly vibrationally excited molecules. Two major goals of this work are: (1) to provide information on potential energy surfaces of combustion related molecules at chemically significant energies, and (2) to test theoretical modes of unimolecular dissociation rates critically via quantum-state resolved measurements.

  20. 15 CFR 970.701 - Significant adverse environmental effects.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REGULATIONS OF THE ENVIRONMENTAL DATA SERVICE DEEP SEABED MINING REGULATIONS FOR EXPLORATION LICENSES... effects of deep seabed mining which cumulatively during commercial recovery have the potential for significant effect. These three effects also occur during mining system tests that may be conducted under...

  1. Estimation of significance thresholds for genomewide association scans

    PubMed Central

    Dudbridge, Frank; Gusnanto, Arief

    2008-01-01

    The question of what significance threshold is appropriate for genomewide association studies is somewhat unresolved. Previous theoretical suggestions have yet to be validated in practice, whereas permutation testing does not resolve a discrepancy between the genomewide multiplicity of the experiment and the subset of markers actually tested. We used genotypes from the Wellcome Trust Case-Control Consortium to estimate a genomewide significance threshold for the UK Caucasian population. We subsampled the genotypes at increasing densities, using permutation to estimate the nominal P-value for 5% family-wise error. By extrapolating to infinite density, we estimated the genomewide significance threshold to be about 7.2 × 10−8. To reduce the computation time, we considered Patterson's eigenvalue estimator of the effective number of tests, but found it to be an order of magnitude too low for multiplicity correction. However, by fitting a Beta distribution to the minimum P-value from permutation replicates, we showed that the effective number is a useful heuristic and suggest that its estimation in this context is an open problem. We conclude that permutation is still needed to obtain genomewide significance thresholds, but with subsampling, extrapolation and estimation of an effective number of tests, the threshold can be standardized for all studies of the same population. PMID:18300295

  2. Statistical Significance and Effect Size: Two Sides of a Coin.

    ERIC Educational Resources Information Center

    Fan, Xitao

    This paper suggests that statistical significance testing and effect size are two sides of the same coin; they complement each other, but do not substitute for one another. Good research practice requires that both should be taken into consideration to make sound quantitative decisions. A Monte Carlo simulation experiment was conducted, and a…

  3. 15 CFR 970.701 - Significant adverse environmental effects.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... REGULATIONS OF THE ENVIRONMENTAL DATA SERVICE DEEP SEABED MINING REGULATIONS FOR EXPLORATION LICENSES... effects of deep seabed mining which cumulatively during commercial recovery have the potential for significant effect. These three effects also occur during mining system tests that may be conducted under...

  4. CSG test

    NASA Image and Video Library

    2011-09-15

    E-2 Test Stand team members at Stennis Space Center conducted their first series of tests on a three-module chemical steam generator unit Sept. 15. All three modules successfully fired during the tests. The chemical steam generator is a critical component for the A-3 Test Stand under construction at Stennis.

  5. Testing Services

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Trace Laboratories is an independent testing laboratory specializing in testing printed circuit boards, automotive products and military hardware. Technical information from NASA Tech Briefs and two subsequent JPL Technical Support packages have assisted Trace in testing surface insulation resistance on printed circuit board materials. Testing time was reduced and customer service was improved because of Jet Propulsion Laboratory technical support packages.

  6. RPR test

    MedlinePlus

    ... more specific test for syphilis, such as FTA-ABS . The FTA-ABS test will help distinguish between syphilis and other ... Elsevier Saunders; 2015:chap 239. Read More FTA-ABS test VDRL test Review Date 9/10/2015 ...

  7. Complexity and significance in computer simulations of physiological systems.

    PubMed

    Kootsey, J M

    1987-06-01

    Complexity in a theoretical model may or may not be associated with a high level of arbitrariness, depending on how the model is constructed. In this paper I use examples from cardiac electrophysiology to illustrate two techniques for maintaining significance in complex simulations. First, the approaches of analysis and synthesis are compared as methods of constructing models of complex systems. When a model is constructed by synthesis of known principles, facts, and subunits, it may have any degree of complexity without losing significance; the same is not true for analysis models. Significance can also be maintained by assembling a limited model to test a specific hypothesis of mechanism.

  8. Composite Testing

    DTIC Science & Technology

    2007-01-01

    Impact Test Matrix for Each Team Impact Tests Qty. Reqd. Per Team Dimensions Steel- GFRP Hybrid Specimen 3 40” x 12” GFRP Control...5: Tension Test Specimen Details Table 2: Tension Test Matrix for Each Team Tension Tests Qty. Reqd. Per Team Dimensions Steel- GFRP Hybrid...Specimen 6 12” L x 1-2” W GFRP Control Specimen 3 12” L x 1-2” W Numerical Modelling A detailed numerical model

  9. Quantifying edge significance on maintaining global connectivity

    PubMed Central

    Qian, Yuhua; Li, Yebin; Zhang, Min; Ma, Guoshuai; Lu, Furong

    2017-01-01

    Global connectivity is a quite important issue for networks. The failures of some key edges may lead to breakdown of the whole system. How to find them will provide a better understanding on system robustness. Based on topological information, we propose an approach named LE (link entropy) to quantify the edge significance on maintaining global connectivity. Then we compare the LE with the other six acknowledged indices on the edge significance: the edge betweenness centrality, degree product, bridgeness, diffusion importance, topological overlap and k-path edge centrality. Experimental results show that the LE approach outperforms in quantifying edge significance on maintaining global connectivity. PMID:28349923

  10. The Real World Significance of Performance Prediction

    ERIC Educational Resources Information Center

    Pardos, Zachary A.; Wang, Qing Yang; Trivedi, Shubhendu

    2012-01-01

    In recent years, the educational data mining and user modeling communities have been aggressively introducing models for predicting student performance on external measures such as standardized tests as well as within-tutor performance. While these models have brought statistically reliable improvement to performance prediction, the real world…

  11. Fostering significant learning in graduate nursing education.

    PubMed

    Marrocco, Geraldine F

    2014-03-01

    Faculty who want to energize graduate students with creative classes that lead to long-lasting learning will benefit by designing course objectives, learning activities, and assessment tools using Fink's taxonomy of significant learning and Wiggins's insights on performance-based or educative assessments. Research shows that course designs relying on content-driven lectures and written examinations do not promote significant learning among adult learners. This article reviews six types of significant learning using Fink's taxonomy and examines Wiggins's "backward" approach to designing courses using performance-based assessments that gauge true learning and learning that promotes a lasting change. When designing courses, educators should ask: "What do I really want students to get out of this course?" The answers will direct the design of objectives, learning activities, and assessment tools. Designing graduate courses using Fink's taxonomy and Wiggins's backward approach can lead to significant learning to better prepare nurse practitioners for the future of health care. Copyright 2014, SLACK Incorporated.

  12. SRS Process Facility Significance Fire Frequency

    SciTech Connect

    Sarrack, A.G.

    1995-10-01

    This report documents the method and assumptions of a study performed to determine a site generic process facility significant fire initiator frequency and explains the proper way this value should be used.

  13. Statistical significance of the gallium anomaly

    SciTech Connect

    Giunti, Carlo; Laveder, Marco

    2011-06-15

    We calculate the statistical significance of the anomalous deficit of electron neutrinos measured in the radioactive source experiments of the GALLEX and SAGE solar neutrino detectors, taking into account the uncertainty of the detection cross section. We found that the statistical significance of the anomaly is {approx}3.0{sigma}. A fit of the data in terms of neutrino oscillations favors at {approx}2.7{sigma} short-baseline electron neutrino disappearance with respect to the null hypothesis of no oscillations.

  14. Building stones can be of geoheritage significance

    NASA Astrophysics Data System (ADS)

    Brocx, Margaret; Semeniuk, Vic

    2017-04-01

    Building stones have generally been assigned values according to their cultural, aesthetic, and rarity significance, amongst other criteria, but they also may have geoheritage significance. This is akin to the geoheritage significance ascribed to minerals and fossils housed as ex situ specimens in museums. We proffer the notion that building stones can be of geoheritage value particularly where they comprise permanent buildings, they illustrate significant windows into the history of the Earth, and they can be visited as an ex situ museum locality (e.g., the "Blue Granite" of Iceland) for education as part of building-stone tours. For some rocks the quarries that supplied the building stone are no longer in existence and hence the building stones provide the only record of that type of material; for other rocks, the building stone may illustrate features in the lithology no longer present in the quarry itself (e.g., rare and large xenoliths). Building stones are particularly significant as they are often polished and manifest structures, fabrics, and textures not evident in outcrop. We illustrate here examples of building stone of geoheritage significance using Australian and International examples. Australian designated stones could include the "Sydney Sandstone" or "Victorian Bluestone". For international examples, there is the famous "Carrara Marble" in Italy and the widely known "Portland Limestone" from southern England, the latter having been utilized for St Pauls Cathedral in London and the UN building in New York City.

  15. Evolution of the Significant Figure Rules

    NASA Astrophysics Data System (ADS)

    Carter, Ashley R.

    2013-09-01

    Today, almost all introductory physics textbooks include standardized "rules" on how to find the number of significant figures in a calculated value. And yet, 30 years ago these rules were almost nonexistent. Whyhave we increased the role of significant figures in introductory classes, and should we continue this trend? A look back at the evolution of significant figures over the last 300 years, from Newton to Millikan to modern authors, sheds some light on their purpose moving forward. While there is much discussion for and against their use, especially in chemistry, a review of earlier versions of the rules suggests that we have lost some items of value, most notably, a significant figure rule for angles. In addition, we have lost the emphasis that the significant figure rules were designed to calculate an approximate (not exact) precision. Now that the significant figure rules are ingrained into our introductory physics sequence, we would be wise to reiterate that these are just general "rules of thumb."

  16. Surface wettability plays a significant role in gecko adhesion underwater

    PubMed Central

    Stark, Alyssa Y.; Badge, Ila; Wucinich, Nicholas A.; Sullivan, Timothy W.; Niewiarowski, Peter H.; Dhinojwala, Ali

    2013-01-01

    Although we now have thousands of studies focused on the nano-, micro-, and whole-animal mechanics of gecko adhesion on clean, dry substrates, we know relatively little about the effects of water on gecko adhesion. For many gecko species, however, rainfall frequently wets the natural surfaces they navigate. In an effort to begin closing this gap, we tested the adhesion of geckos on submerged substrates that vary in their wettability. When tested on a wet hydrophilic surface, geckos produced a significantly lower shear adhesive force (5.4 ± 1.33 N) compared with a dry hydrophilic surface (17.1 ± 3.93 N). In tests on an intermediate wetting surface and a hydrophobic surface, we found no difference in shear adhesion between dry and wet contact. Finally, in tests on polytetrafluoroethylene (PTFE), we found that geckos clung significantly better to wet PTFE (8.0 ± 1.09 N) than dry PTFE (1.6 ± 0.66 N). To help explain our results, we developed models based on thermodynamic theory of adhesion for contacting surfaces in different media and found that we can predict the ratio of shear adhesion in water to that in air. Our findings provide insight into how geckos may function in wet environments and also have significant implications for the development of a synthetic gecko mimic that retains adhesion in water. PMID:23576727

  17. Surface wettability plays a significant role in gecko adhesion underwater.

    PubMed

    Stark, Alyssa Y; Badge, Ila; Wucinich, Nicholas A; Sullivan, Timothy W; Niewiarowski, Peter H; Dhinojwala, Ali

    2013-04-16

    Although we now have thousands of studies focused on the nano-, micro-, and whole-animal mechanics of gecko adhesion on clean, dry substrates, we know relatively little about the effects of water on gecko adhesion. For many gecko species, however, rainfall frequently wets the natural surfaces they navigate. In an effort to begin closing this gap, we tested the adhesion of geckos on submerged substrates that vary in their wettability. When tested on a wet hydrophilic surface, geckos produced a significantly lower shear adhesive force (5.4 ± 1.33 N) compared with a dry hydrophilic surface (17.1 ± 3.93 N). In tests on an intermediate wetting surface and a hydrophobic surface, we found no difference in shear adhesion between dry and wet contact. Finally, in tests on polytetrafluoroethylene (PTFE), we found that geckos clung significantly better to wet PTFE (8.0 ± 1.09 N) than dry PTFE (1.6 ± 0.66 N). To help explain our results, we developed models based on thermodynamic theory of adhesion for contacting surfaces in different media and found that we can predict the ratio of shear adhesion in water to that in air. Our findings provide insight into how geckos may function in wet environments and also have significant implications for the development of a synthetic gecko mimic that retains adhesion in water.

  18. Meaning reconstruction in bereavement: sense and significance.

    PubMed

    Hibberd, Rachel

    2013-08-01

    Recently there has been growing empirical and theoretical attention to the role of meaning in grief along with increased recognition of the need for more sophisticated definitions of meaning. The present article highlights philosophical issues inherent in the study of meaning and grief reviews the place of meaning in current theories of grief and provides a brief overview of the ways that meaning has been operationalized by grief researchers, including sense-making, benefit finding, identity change, and purpose in life. It is argued that, in our focus on the ways mourners make sense of loss, we have neglected an important aspect of meaning: life significance. Life significance is the felt perception that some aspect of one's life experience "matters." The construct is explored as a potentially important outcome of bereavement; mourners may lose life significance along with their lost loved one, or they may develop new avenues to life significance as they confront mortality and rebuild shattered worldviews. Related literature, such as appreciation of life as a facet of posttraumatic growth, is surveyed for clues as to the role of life significance in grief. Suggestions for future study are offered.

  19. Significance of Lead Residues in Mallard Tissues

    USGS Publications Warehouse

    Longcore, J.R.; Locke, L.N.; Bagley, George E.; Andrews, R.

    1974-01-01

    Tissues of adult, lead-dosed mallards that either died or were sacrificed were analyzed for lead. Lead levels in brains, tibiae, and breast muscle of ducks that died and in tibiae of ducks that were sacrificed increased significantly from dosage until death. Lead in the heart, lung, and blood from sacrificed ducks decreased significantly from dosage until death. Lead concentrations in tissues from ducks in the two groups were not significantly different except for the liver, kidney, and lung. Average lead levels in the livers and kidneys of ducks that died were significantly higher than those in ducks that were sacrificed. The mean concentration of lead in the lungs of the ducks sacrificed was significantly higher than the mean level in the lungs of ducks that died. Measurements of the lead concentrations in this study, when compared with lead levels reported in the literature for avian and non-avian species, showed that arbitrary diagnostic levels indicating lead poisoning could be set. In mallard ducks, lead levels exceeding 3 ppm in the brain, 6 to 20 ppm in the kidney or liver, or 10 ppm in clotted blood from the heart indicated acute exposure to lead.

  20. Potassium test

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003484.htm Potassium test To use the sharing features on this ... enable JavaScript. This test measures the amount of potassium in the fluid portion (serum) of the blood. ...